Acceptance type: Oral

9

An Introduction: Institutional framework to implement Antarctic governance based on best available science

Professor Akiho SHIBATA

Kobe University PCRC, Kobe, Japan

Abstract

Article 10 of the Madrid Protocol (1991) mandates the ATCM, when defining general policies for the comprehensive protection of the Antarctic environment and adopting measures for the implementation of the Protocol, to “draw… upon the best scientific and technical advice available”. Article IX of the CCAMLR (1980) also mandates its Commission in giving effect to the objective and principles of the Convention to formulate and adopt conservation measures “on the basis of best scientific evidence available”. The general principle that Antarctic governance be based on best available science (BAS) seems to be well established. However, its implementation and practical operationalization of the principle continues to raise controversies. These controversies are compounded by unique decision-making process in the Antarctic Treaty System based on consensus.

This brief introductory presentation will first analyze a few recent cases in the ATCM/CEP where the implementation and/or interpretation of BAS was an element of the difficulties in obtaining consensus amongst the Consultative Parties. Second, this presentation will examine the institutional and procedural mechanisms established and being evolved within the ATCM/CEP, focusing on the role of SCAR in such mechanisms, their original objective had been precisely to effectively operationalize the above principle. Finally, through such examination, this presentation seeks to suggest some of the root causes of the recent difficulties in effectively implementing the principle of Antarctic governance based on BAS.

12

Temperature sensing proteins expressed in Antarctic fish across species pairs independently re-adapted to temperate waters

Julia York¹, Leyla Cardenas², Christina Cheng-De Vries¹

¹University of Illinois Urbana-Champaign, Urbana, USA. ²Universidad Austral de Chile, Valdivia, Chile

Abstract

Antarctic notothenioid fishes have adapted to their frigid, stable thermal environment over more than 15 million years. Previous work has uncovered temperature dependent activity of proteins expressed in sensory tissue in Antarctic species, but recent findings in mammals highlight the contributions of other tissues, such as skin, in generating thermosensory responses. These responses are key for fish behavioral thermoregulation with implications for reproduction, distribution, metabolism, and disease. Here, we compare transcriptomic expression of proteins involved in thermosensation across peripheral sensory tissue, central sensory tissue, skin, and gill with non-thermosensing nervous and somatic issues in notothenioid fishes. We investigated changes in both structural and regulatory evolution to ask how thermosensory protein expression changes between tissues. Further, we compare species adapted to Antarctic temperatures (between -2 and +2°C) with congeneric species that have escaped the Southern Ocean and re-adapted to temperate waters around Chile and New Zealand (8-10°C) to provide multiple, recent, and independent evolutionary comparisons. Expression is assessed using third generation (long-read) sequencing technologies in parallel with increasingly available, high-quality genome datasets.

13

A new proxy for detection surface environmental variations by using infrasound waves in the coastal area of the Lützow-Holm Bay, East Antarctica

Dr. Masaki Kanao¹, Mr. Takahiko Murayama²

¹National Institute of Polar Research, Tokyo, Japan. ²Japan Weather Association, Tokyo, Japan

Abstract

Time-space variations of infrasound source locations were studied for three years in 2018-2020 by using a combination of two local arrays in the Lützow-Holm Bay region (LHB), East Antarctica. The local arrays deployed at two coastal outcrops clearly detected temporal variations in frequency content as well as propagating directions during the whole three years. Many infrasound sources were detected and majority of them revealed to be located between northward and north-westward directions viewed from the arrays. These source events are generated within the Southern Indian Ocean and the northern part of LHB with frequency content of few seconds; that is the “microbaroms” originated from oceanic swells. From austral summer to fall seasons, in contrast, many infrasound sources orientation are determined to be north-eastward direction. These sources might be related to the effects of katabatic winds in the continental coastal area. Furthermore, several sporadic occurring infrasound events during wintering seasons had predominant frequency content of few Hz, which were clearly higher than those of the microbaroms. Based on a comparison with sea-ice and glacier distribution form MODIS satellite images, these high-frequency sporadic sources could be cryo-seismic signals associated with cryosphere dynamics near the local arrays. In these regards, infrasound wave could be a useful proxy for monitoring surface environment involving meteorological variations in the coastal area of Antarctica.

14

Sharing the data and metadata under FAIR principle by the National Antarctic Data Center in Japan

Dr. Masaki Kanao

National Institute of Polar Rsearch, Tokyo, Japan. Research Organization of Information and Systems, Tokyo, Japan

Abstract

Polar Environmental Data Science Center (PEDSC) of the Joint Support-Center for Data Science Research (DS), the Research Organization of Information and Systems (ROIS) has a responsibility to manage, share and publish data from Japanese research activities in polar regions as the National Antarctic Data Center (NADC), in tight collaboration with the National Institute of Polar Research (NIPR). Data policy of PEDSC was established in February 2007, based on the requirements of the Standing Committee on Antarctic Data Management (SCADM) of the Scientific Committee on Antarctic Research (SCAR). From the era of International Polar Year (IPY2007-2008), a significant number of multi-disciplinary data have been compiled and published. These collected data and metadata have a linkage with the Global Change Master Directory (GCMD), the Polar Information Commons (PIC) at the IPY, together with several data centres in the World Data System (WDS). Involving data activities of SCAR and the International Arctic Science Committee (IASC), tight linkages of data sharing and publication among the Asian Forum for Polar Sciences (AFoPS) countries has been operating. In this presentation, a brief history of polar data management under FAIR principle is introduced relating PEDSC activities, focusing on data/metadata sharing, multi-disciplinary interoperable databases, international collaboration among global data committees, data publication and citation, as well as the publication into data journal (Polar Data Journal).

15

Uniqueness of the Photosynthetic and Hydraulic Ecophysiological Traits of Antarctic Vascular Plants

Uniqueness of the Photosynthetic and Hydraulic Ecophysiological Traits of Antarctic Vascular Plants Pedro Flores Branttes¹, Patricia Sáez², Francisca Fuentes², Valentina Vallejos¹, Leon Bravo², Lohen Cavieres¹, Jeroni Galmés³

¹Universidad de Concepción, Concepción, Chile. ²Universidad de la Frontera, Temuco, Chile. ³Universitat de les Illes Balears, Mallorca, Spain

Abstract

Deschampsia antarctica and Colobanthus quitensis are the only two vascular plant species that have successfully colonized the extreme climatic conditions of Antarctica. In addition to being widely distributed across almost the entire Maritime Antarctica from 62°S to 68°S, there are also reports of their presence along the Andes Mountain range up to 56°S. Under Antarctic conditions, these plants exhibit morphological and biochemical characteristics adapted to stressful environmental conditions such as freezing, drought, nutrient scarcity, and intense radiation. They also display strongly xerophytic leaf adaptations with thick and lignified cell walls. This results in a substantial reduction in CO2 conductance during photosynthesis, compensated by a Rubisco highly specific for CO2. Therefore, the photosynthetic performance of Antarctic plants is predominantly governed by diffusion components associated with gm, along with biochemical determinants linked to the kinetic traits of Rubisco. Despite extensive knowledge of the physiological traits of Antarctic vascular plants, gaps persist regarding the uniqueness of these features. Specifically, it remains unclear whether these physiological traits are solely determined by the Antarctic climate, making them unique to species growing in Antarctica, or if they are also present in populations outside Antarctica or in phylogenetically related species inhabiting similarly hostile climates. The objective was to compare the photosynthetic and hydraulic characteristics of Antarctic vascular plant populations with those of related species growing in subantarctic and Antarctic environments. Evaluations included anatomical features, photosynthetic functional traits (gs, gm, vmax), and hydraulic characteristics (Kleaf, hydraulic diameter, vein architecture) in plants cultivated in chambers under different thermal regimes. Acknowledgments: FONDECYT 1211231; ANILLO ACT210038.

23

Antarctic Governance: Bridging the Nexus of Science and Law in International and Indian Antarctic Act, 2022

Mr Chinmay Kumar Patra

Space Applications Centre ISRO, Ahmedabad, India

Abstract

Antarctica necessitates a delicate balance between scientific exploration and legal frameworks, as this equilibrium is crucial for preserving the pristine environment for the next generation. This research scrutinizes the evolving Antarctic governance through the lens of the enacted Indian Antarctic Act, 2022 whose objective is to demilitarise Antarctica and discuss the use of Antarctica for peaceful purposes. The study explores the intricate interplay between the Antarctic Treaty System and India's domestic legislation, shedding light limited to permitted area of Antarctica to India. The paper critically assesses the effectiveness of these global instruments in facilitating international collaboration in scientific research while addressing environmental concerns. A comparative analysis of various chapters of the act is the core of the research, juxtaposing India's Antarctic legislation with that of other Antarctic stakeholders, aiming to ensure conservation of Antarctic marine living resources and eliminate activities such as mining or illegal practices. The study delves into the unique characteristics of Indian Antarctic Act, 2022, highlighting its distinctive approach to regulating scientific activities, such as issuing permits for introducing non-native animals and plants into Antarctica, permitting the introduction of microscopic organisms, overseeing waste disposal, and regulating discharge into the sea. As Antarctica grapples with contemporary challenges such as climate change and resource exploitation, the paper evaluates the adaptive capacity of Indian Antarctic Act, 2022, considering how the Indian legislation responds to emerging geopolitical considerations, thereby shaping India's role in the global Antarctic governance. In conclusion, the research paper synthesizes the intricate relationships between science and law in Antarctic governance, providing a comprehensive understanding of the Indian perspective by extending the jurisdiction of Indian courts to Antarctica. The findings serve as a foundation for policymakers, researchers, and stakeholders interested in India's role in the sustainable management of Antarctica.

24

Cultural Engagement in the Frozen Frontier: Exploring Artistic and Cultural Activities in the Indian Scientific Expedition at Bharati Research Station

Mr Chinmay Kumar Patra¹, Mr Sahal Mohammed M.N.², Dr. Neeraja Balakrishna³, Mr Mohit Kumar Sharma⁴

¹Space Applications Centre ISRO, Ahmedabad, India. ²ISRO Telemetry Tracking and Command Network, Bengaluru, India. ³Sri Atal Bihari Vajpayee Medical College and Research Institute, Bengaluru, India. ⁴Council of Scientific and Industrial Research - IPU, New Delhi, India

Abstract

Antarctica, an expanse of scientific inquiry, provides a unique setting for the intersection of culture and exploration. This research delves into the cultural activities undertaken during Indian scientific expeditions at the Bharati Research Station, offering a comprehensive analysis of how the human spirit thrives in this extreme and isolated environment. Cultural heritage is a crucial aspect of an expedition which encompasses a collection of elements that come together to create a subconscious and elusive Antarctic experience. This experience highlights the collaborative efforts of scientific and logistics personnel, forming a cultural tapestry that transcends the scientific mission. An exploration of cultural activities encompasses a variety of expressions, including the celebration of Indian festivals, national and international days, musical programs, photography competition, videography competition, movie production, paintings, etc. The study, based on 14 months of qualitative statistical data, illustrates how participants with limited resources engage in cultural activities to produce works that capture the challenges of isolation. It also explores the camaraderie among expedition members, scrutinizing its impact on the well-being and cohesion of members during the dark winter. Moreover, the study assesses the influence of cultural activities on the formation of a distinct Antarctic identity within the global scientific community. Participating in cultural activities is crucial for shaping the human mind, offering a powerful outlet for self-expression, emotional exploration, and fostering mental well-being. In conclusion, the research paper synthesizes the multifaceted dimensions of cultural activities, exemplified by artistic expressions such as movie production for the Winter International Film Festival of Antarctica (WIFFA), organization of a master chef competition, and the utilization of social media to promote art during the 42nd Indian scientific expedition. The findings provide valuable insights for future expeditions and underscore the importance of cultural engagement in fostering a rich and inclusive Antarctic exploration experience.

28

Swarm Robotics: A New Approach for Antarctic Scientific Exploration

Mr. Rogelio Morales¹, Mr. José Zambrano², Mr. Frank Villahermosa²

¹Agencia Bolivariana para Actividades Espaciales, Caracas, Venezuela, Bolivarian Republic of. ²Minister of Science and Technology, Caracas, Venezuela, Bolivarian Republic of

Abstract

Antarctica represents a major challenge for scientists in terms of exploration, research, and understanding. It's one of the harshest places on Earth, which makes effective Antarctic exploration and study very difficult. Under these circumstances, robotic platforms represent a valid tool for the in-depth study and understanding of the continent, offering a variety of capabilities for air, surface, and underwater scenarios. However, the development of these robotic missions is essentially a risky and difficult activity that often coexists with the uncertainty and adverse conditions of remote operations in one of the coldest, driest, and windiest environments, with no options for help or rescue. In this sense, to increase the chances of survival and scientific mission success, swarm robotic systems are proposed as a new approach for Antarctic scientific exploration. Swarm robotics is a field of research in artificial intelligence responsible for the development of new organization and coordination mechanisms, decentralized and distributed, of robotic entities with relatively simple structures that develop intelligent collective behavior through their interaction with other entities and their environment to solve complex tasks. All these characteristics provide a robust and reliable platform that allows the exploration of the continent on a new scale and scope. However, it also presents new challenges for managing high levels of complexity in communications and networks, control and navigation systems, and data management. In addition, Antarctica could provide a potential analog environment and testbed for future platforms for robotic space exploration. Finally, three robotic prototypes have been proposed as Autonomous Exploration Units (AEU) for Antarctic conditions. These include Gavilán-X for airborne exploration, Bachaco-X for legged surface exploration, and Kotúa-X for underwater exploration. The rationale behind their design has been the subject of careful study and analysis.

29

Euphausiids Unveiled: Comprehensive Study of E. superba, E. crystallorophias and E. triacantha Diet – a DNA metabarcoding and Stable isotope approach.

Camila Cataldo-Mendez^1,2,3, Associate Professor Kerrie Swadling^1,2, Dr Alison Cleary⁴, Dr Leonie Suter³, Dr Christine Weldrick^1,2

¹Institute for Marine and Antarctic Studies, Hobart, Australia. ²Australian Antarctic Partnership Program, Hobart, Australia. ³Australian Antarctic Division, Hobart, Australia. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

Krill species play an important role in the East Antarctic ecosystem and have historically been studied predominantly for their economic importance, with Antarctic krill (Euphausia superba) given the most attention regarding their dietary preferences. However, this study expands our understanding by including two lesser-studied krill species: crystal krill (Euphausia crystallorophias) and tri-spined krill (Euphausia triacantha).

Species were collected in overlapping distributions/stations, offering the opportunity to investigate whether different krill species either compete for resources or exhibit distinct dietary preferences when coexisting in the same geographical area. This study uses a combination of methods to examine the diets of Antarctic euphausiids. DNA metabarcoding analysis, performed on stomach samples, provides a snapshot of their diet at the time of capture, while stable isotope analysis on muscle tissue sheds light on the origin of resources used for growth. Additionally, this approach yields valuable trophic information, including trophic position, niche width, and the extent of dietary overlap among species.

Notably, this research marks the first investigation of E. superba specimens captured on the seafloor, representing a significant milestone in the field. Preliminary findings indicate that when E. superba and E. crystallorophias overlap in their habitats, they have a dietary shift, evidentiate by changes in trophic position. This study enhances our comprehension of the complex interplay between krill species and their interactions within the East Antarctic ecosystem, offering critical insights into their ecological roles and resource utilization.

39

Psychological Wellbeing, Emotion Rulation, and Resilience of Indian expeditioners inAntarctica: Longitudinal lnvestigation

Professor Azizjuddin Khan

Indian Institute of Technology Bombay, India, Mumbai, India

Abstract

The present study is an extension of author's previous work. Wintering in Antarctica environment is quite challenging for the expeditioners. There are physical, psychologicaland socialchallenges. However, Human is quite adaptive. Expeditioners attempt to face challenges posed by dyanamic and extrement environemnt of Anyarctica. However, there is a constant challenge to the health and welling being of individual. The aim of the study was to investigate psychological well being, resilence and emotion regulation during long term stay in Antarctica. The data was collected during January 2021 (N=19), June 2021(N=1and December 2021(N=17) from Bharatistation, Antar,ljic, a. Three questionna, namely Psychological well being (PSW), emotional regulation, and Resilence were administered. The data was analysed using 3 x 6 mixed analysis variance with condittion as between and psychological wellbeing as within subject variable A 3x2 mixed analysis variance with condition as between subject and emotion regulation as within subject variatt,and 3 x3 mixed analysis variance with condition as between subject and Resilence as within subject variable. The results showed that all main effects were significant, and some interactions were also significant. Psychological well being {F (5, 255) = 27.78, <0.001},condition {F (2, 51) =3.09 <0.05, and interaction between psychological well being and condition was {F (10, 255) = 2.15, <0.021} was significant. During the beginning of the stay, emotion was low as compared to middile or end of the expedition. Similarly. results revealed that psycholgical well being and resilence was reported quite favourable during beginning and end of the expedition. The present investigation has strong bearing on future exped itioners for their well-being during wintering 1n Antarctica. One of the flaws of the study could that only questionnaires were used for the data collection which can be taken care by future studies by using laboratory based investigation.

40

Antarctic benthic ecological change

Dr Huw Griffiths¹, Dr Vonda Cummings², Dr Anton Van de Putte^3,4, Dr Rowan Whittle¹, Dr Catherine Waller⁵

¹British Antarctic Survey, Cambridge, United Kingdom. ²National Institute of Water and Atmospheric Research, Wellington, New Zealand. ³Royal Belgian Institute for Natural Sciences, Brussels, Belgium. ⁴Université Libre de Bruxelles, Brussels, Belgium. ⁵University of Hull, Hull, United Kingdom

Abstract

The seafloor around Antarctica is home to a diverse and highly endemic community that evolved in near-isolation and freezing temperatures. These cold-adapted species are under threat from local and global drivers, including warming, acidification and changes to the cryosphere. This Review summarises knowledge of Antarctic benthic ecological change. The nature of change varies with location, depth and community type, with the greatest changes observed in the shallows of West Antarctic Peninsula. These include the emergence of newly exposed coastline (leading to new habitats) and decreased sea ice and increased iceberg scour and turbidity, causing regional increased mortality rates and decreased diversity, primary production, carbon storage and spatial competition. The magnitude and extent of these changes is projected to increase in the future, with tipping points in physiological limits, primary productivity and competition likely to be reached before the end of this century. These changes will impact overall ecosystem health, stability and uniqueness of Antarctic benthic ecology, resulting from a homogenisation of communities as endemic cold water species shrink in range and cosmopolitan species shift southwards. The extent of benthic change is poorly understood, and primarily limited to a handful of shallow water taxa, necessitating the use of new and emerging technologies to fill geographic, bathymetric, seasonal and taxonomic gaps.

41

Centennial variability of the southern hemisphere westerly winds and of the southern annular mode over the past millennia

Hugues Goosse

Université catholique de Louvain, Louvain-la-Neuve, Belgium

Abstract

Many observational evidences suggest large shifts in the position and strength of the southern hemisphere westerly winds (SHWW) at the centennial timescale over the past millennia, or of the strongly related Southern Annular Mode (SAM). However, no consistent view has emerged up to now on the timing of those variations and their spatial extent. It is thus difficult to determine when shifts actually occurred and if the suggested changes in the SHWW are regional features or if they are consistent across all longitudes. One additional issue is that climate models are in general not able to reproduce such large centennial variations in the SHWW. The goal of this presentation is to review existing evidence of SHWW variations based on different types of records influenced by local wind conditions such as those from trees, glaciers and lakes as well as from multiproxy reconstructions. The inter-hemispheric gradient of ¹⁴C in atmospheric CO₂, which are also strongly influenced by the SHWW, will provide an additional large-scale constraint. The periods that may be characterized by a shift in the SHWW will be identified and the potential origin of the discrepancies between records discussed.

42

Role of atmospheric and oceanic processes in the variability of Antarctic sea ice extent over the period 1958-2023

Hugues Goosse¹, Quentin dalaiden¹, Feba Francis¹, Bianca Mezzina¹, Ryan Fogt²

¹Université catholique de Louvain, Louvain-la-Neuve, Belgium. ²Ohio University, Athens, USA

Abstract

The Antarctic sea ice extent has displayed several regime shifts over the past 65 years. Consistent lines of evidence indicate a decline in Antarctic sea ice extent from 1958 to 1978, which precedes the availability of continuous satellite observations. Subsequently, there was a significant sea ice expansion over 1979–2015 before the large drop observed in the past few years that led to record lows. The origin of those shifts and contrasting trends are analyzed here using a new reconstruction of atmospheric temperature, sea level pressure and sea ice extent spanning the period 1958-2023. The reconstruction employs a data assimilation method that combines long simulations and large ensembles performed with climate models with long-term station-based records of temperature and sea level pressure at high latitudes of the Southern Hemisphere. The reconstruction is thus totally independent from sea ice extent observations that are used as validation, showing the good performance of the method. The sea-ice-ocean model NEMO is then driven by an atmopsheric forcing derived from this reconstruction over the period 1958-2023. In contrast to previous reconstructions and estimates, reconstructing simultaneously the atmospheric circulation, temperature, and then driving a sea ice ocean model with a forcing based on this reconstruction ensures compatibility among the variables and thus a more straightforward dynamical interpretation. Our results indicate that no single atmospheric circulation mode could be simply related to the regime shifts in sea ice extent trends. However, the covariance structure of the temperature strongly varies across periods, with more homogenous temperature anomalies for the early and recent periods and a more complex spatial pattern for the years 1979–2015. The ocean and sea ice integrate this atmospheric forcing leading to the observed trends.

43

The Political Power of Common Heritage in Antarctic Governance Debates

Dr Peder Roberts

University of Stavanger, Stavanger, Norway

Abstract

This paper explores the political life of the concept of "common heritage of humankind" in debates over Antarctic natural resource governance. The common heritage concept was first mentioned in negotiations over the UN Convention on the Law of the Sea (UNCLOS) in 1958. The Maltese diplomat Arvid Pardo pushed the principle from the late 1960s precisely because he felt it could help to reverse inequalities in economic and political power between developed and developing states, and while Pardo was disappointed with its lack of prominence, the concept did make it into the final convention in 1982. Would this concept be applicable to the emerging discussions about a minerals governance regime in Antarctica? Legal opinions tended to be negative, but I argue that the political value of the common heritage concept persisted independent of its precise legal applicability, because it highlighted a more fundamental injustice within the ATS. Critiques of the system's lack of accountability to the world as a whole resonated with wider concerns over economic justice held by the Group of 77 developing states. Yet ATS membership cut across traditional divides between the global north and the global south, and arguments comparing the ATS to colonialism proved more difficult to sustain than elsewhere in the world. Abandoning the Convention on the Regulation of Antarctic Mineral Resources Activities and introducing the Protocol on Environmental Protection (the Madrid Protocol) allowed ATS members to claim continued legitimacy while preventing further economic injustice: a pie with no slices cannot be divided unequally.

46

Antarctica in Chilean schools: Inclusion of new narratives and the use of technology in the educational curriculum. Insights and challenges

Antarctica in Chilean schools: Inclusion of new narratives and the use of technology in the educational curriculum. Insights and challenges Nadia Politis, Antarctica in Chilean schools: Inclusion of new narratives and the use of technology in the educational curriculum. Insights and challenges Julieta Orlando, Antarctica in Chilean schools: Inclusion of new narratives and the use of technology in the educational curriculum. Insights and challenges Emanuel Sotelo

BASE Millennium Institute of Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago, Chile

Abstract

Currently, Antarctica is not considered in Chile's educational curriculum. Despite some efforts to include topics such as climate change and history in the classroom, there is no public policy that officializes its inclusion, despite the scientific evidence that places Antarctica as a key element for ecosystems. A scenario that creates challenges for teachers, their students, and also student teachers. Future teachers.

Through initiatives such as the "BASE Educational Public Policy Notebooks", the "Augmented Antarctic Reality (AAR)" project, and the training of future teachers in Antarctic issues, the "Schools and Teaching Unit of the BASE Millennium Institute" aims to share its experience working with educational institutions.

The introduction of the tool " Educational Planning" , the exchange of experiences with teachers, and the inclusion of digital technologies to create narratives adapted to each Chilean educational environment The inclusion of the tool "Educational Planning", the exchange of experiences with teachers, and the inclusion of digital technologies to create narratives adapted to each Chilean educational environment (variable and dissimilar in each region and neighborhood) are part of the efforts led by an interdisciplinary group of professionals… What do teachers think? What are their needs? What do they need to know about Antarctica? These are some of the questions that seek to add new approaches and answers.

47

In situ preservation in the South Shetland Islands: the "lifespan" of archaeological remains below the 60th parallel south

Gerusa de Alkmim Radicchi

UFMG, Belo Horizonte, Brazil

Abstract

The presentation aims to show a methodology related to the understanding of the in situ preservation state of the materials left by seal hunters from the earlier decades of the 19th century in Antarctica. These remains are found in high concentration at archaeological sites on the South Shetland Islands, especially on the Byers Peninsula (Livingston Island). Based on the study of open data libraries available on the Antarctica environment, including soil characterization, climate, human presence, biodiversity, and the sort of archaeological artifacts already excavated (bones, metals, textiles, leathers, ceramics, etc.), the methodology can perform a basic pre-diagnosis about the transformation of these records by the environment and throughout time.

The proposal has been developed within the scope of the Laboratory of Antarctic Studies in Human Sciences (LEACH-UFMG, Brazil) in the last few years. LEACH has the largest collection of archaeological remains found in hunting shelters resulting from the 19th century in the South Shetland Islands and has been in charge of projects for mapping, excavating, and studying the sites for more than ten years.

We do not intend to exhaust the answers about the natural transformation process of archaeological remains in Antarctica or present a methodology based on physicochemical analyses that, in most cases, are not easily available to human sciences actors. Instead, we are proposing a quite friendly and innovative set of steps that can equip professionals and researchers to understand the condition in which the sealers' artifacts have been found in the archaeological context, to apply it to the archaeological studies, to the collection conservation, and to make decisions on the management of sites, and for planning further excavations.

48

Frontiers of Space Weather Research: The Role of AASWO in Antarctic Monitoring

Dr. Adriana Maria Gulisano^1,2,3, Dr. Sergio Dasso^2,3,4, Eng. Lucas Tomás Rubinstein^2,5, Tech. Omar Areso², Eng. Matías Hernán Pereira², Lic. Noelia Ayelén Santos⁴, Lic. Christian Gutiérrez^4,2

¹Instituto Antártico Argentino/Dirección Nacional del Antártico, Buenos Aires, Argentina. ²CONICET, Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio, grupo LAMP, Buenos Aires, Argentina. ³Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, Buenos Aires, Argentina. ⁴Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias de la Atmósfera y los Océanos, grupo LAMP, Buenos Aires, Argentina. ⁵Universidad de Buenos Aires, Facultad de Ingeniería, Departamento de Electrónica, Laboratorio de Acústica y Electroacústica, Ciudad Autónoma de Buenos Aires, Argentina

Abstract

The Argentinean Antarctic Space Weather Observatory (AASWO) is at the forefront of advancing the understanding of space weather phenomena. Established in February 2019, the first AASWO node operates a state-of-the-art space weather laboratory at the Argentinean Antarctic Marambio base. This facility, constructed and maintained by the Argentine Space Weather Laboratory (LAMP, 'Laboratorio Argentino de Meteorología del esPacio'), houses various instruments including a cosmic ray detector, magnetometers, and a meteorological station. Crafted to endure the formidable Antarctic conditions, the laboratory boasts robust infrastructure engineered to withstand extremely low temperatures and the high winds prevalent in the region . Its advanced systems include redundant power sources utilizing gel batteries, materials resistant to Antarctic conditions, and precise GPS time stamping for data records. Real-time data acquisition ensures timely transmission of information to LAMP servers located in our headquarters in Buenos Aires, facilitating the provision of operational space weather products through the LAMP web portal. In furthering its mission, AASWO is expanding its network of space weather laboratories. A new facility is currently under installation at another Argentinean base within the Antarctic Circle, the San Martín Laboratory, its second node. This expansion project is being carried out during the Austral Summer Campaign 2024. By strategically situating these laboratories in Antarctica, AASWO aims to fill critical measurement gaps in space weather monitoring coverage at high latitudes. Discussions are currently ongoing regarding the integration of data acquired by the Cherenkov detectors into the NMDB (Neutron Monitor Database)following thorough testing and calibration procedures. This integration will provide a significant benefit to the scientific community at large, ensuring broader access to valuable data and enhancing collaboration across research efforts.

50

Ice shelf-polynya interaction on Antarctic coast and a next generation observing platform

Dr. Weifeng Zhang¹, Dr. Catherine Walker¹, Dr. Michael Jakuba¹, Dr. Rubao Ji¹, Dr. Yun Li², Dr. Ted Maksym¹, Yilang Xu¹

¹Woods Hole Oceanographic Institution, Woods Hole, USA. ²Univ. of Delaware, Newark, USA

Abstract

This study examines the interaction between Antarctic coastal polynyas and neighboring ice shelves with cavities underneath. It focuses on the processes of i) wintertime polynya destratification affecting ice shelf basal melt through changing intrusion of cold dense water into the ice shelf cavity and ii) the dynamics of ice shelf melt affecting springtime restratification in polynyas. The influence of winds, air temperature, initial stratification, ice tongue, and coastal geometry on wintertime polynya destratification are analyzed. The influences of different meltwater sources, i.e., sea ice melt, ice shelf basal melt, and ice shelf surface runoff, on the springtime near-surface restratification in the polynya water column are quantified. An ice-shelf/sea-ice/ocean coupled high-resolution numerical model and fundamental principle-based scaling analysis are used together to characterize the de/re-stratification dynamics in polynyas and their interaction with ice shelves in various configurations. This work stresses the key role of small-scale polynya processes and their interaction with ice shelves, and calls for a new generation of observing system that can systematically capture temporal and spatial variability of the local interactive processes. For that, a new concept of Self-deploying Autonomous Mooring System (SAMS) is proposed to be deployed in ice shelf cavities and nearby polynyas. Together with mobile observing platforms, SAMS is to characterize long-term and large-scale variabilities of the interactive processes between Antarctic coastal ocean and ice shelves and to quantify the impact of large-scale atmospheric and oceanic processes on Antarctic ice shelf melt.

52

A study into the insulative effects of snow on flat roofs under extreme conditions.

Prof Rich Fitton, Mr Grant Henshaw

University of Salford, manchester, United Kingdom

Abstract

Research centres in extreme climates should be well insulated, provide good levels of thermal comfort and have minimal impacts on the natural environment. Generally, these metrics are modelled and are taken as fact. However, research over many years has illustrated a performance gap between buildings as modelled at the design stage and the performance of the same buildings as measured once built in terms of heat loss through elements. In cold climates snow has been shown in past studies to provide a layer of insulation that can help reduce thermal transmission. Snow also has very dynamic characteristics during the changes that occur from onestage of it life cycle to another (eg, ice, snow, slurry, sludge). A study being carried out at the Energy House 2 Research Facility at the University of Salford, Manchester, using a set of large climatic chambers will create real snow on the roof the complete, contained test house and in the chamber and cycle the snow load through a range of temperatures. Measurements are taken of surface/air temperature and heat flux to determine the measured U-value of the flat roofed structure at different points in the degredation of the snow load. The research presents a real and dynamic view of the insulating effects of snow on a flat roof that can then be used to help calibrate energy models of polar research bases.

58

The unique challenges and opportunities of recognizing the Rights of Antarctica

Professor Alejandra Mancilla, Dr Patrik Baard

University of Oslo, Oslo, Norway

Abstract

At the time of writing, an Antarctic Declaration is being drafted by an international interdisciplinary group, which defines Antarctica as an “indivisible, autonomous and self-regulating community of inter-dependent beings that has a unique presence and spirit, and plays a vital and indispensable role in maintaining conditions conducive to the flourishing of life on Earth”. Starting from this, the Declaration proposes—among other things—to give Antarctica legal status and the right to be represented on an equal footing with other states in international fora. While the Declaration’s advocates see it as a new step in the recognition of Rights of Nature globally (based on the concept of the intrinsic value of nonhuman natural entities), there are important differences between these cases. In this article, we examine the commonalities and differences between Rights of Nature elsewhere and Rights of Antarctica, and some particular challenges for the latter. We then explore the possibility of a “piecemeal approach” that would give rights to parts of Antarctica (for example, some Specially Protected Areas), and suggest why, despite some advantages, this would be overall inadvisable. We conclude that accepting the Rights of Antarctica requires further conceptual and legal innovation from Rights of Nature elsewhere. At the same time, it would constitute a unique opportunity for international law and maybe even a model from which domestic legislatures could also draw, particularly regarding the choice of representatives for nonhuman natural entities.

60

Modes of climate variability as drivers of macronutrient variability in the Southern Ocean

Dr. Thiago Monteiro¹, Dr. Sian F. Henley², Dr. Ricardo C.G. Pollery³, Dr. Carlos R.B. Mendes¹, Dr. Mauricio M. Mata¹, Dr. Virginia M. Tavano¹, Dr. Carlos A.E. Garcia¹, Dr. Rodrigo Kerr¹

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²The University of Edinburgh, Edinburgh, United Kingdom. ³Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Macronutrients are critical to supporting strong biological carbon uptake and storage in the Southern Ocean. Temporal variability in macronutrient concentrations is an important factor in several coupled ocean-atmosphere processes. Here, we demonstrate that the Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO) play a key role in driving the interannual variability of macronutrient concentrations along the northern Antarctic Peninsula during summer. In years of positive SAM, the dissolved inorganic nitrogen (DIN) concentration can increase significantly by up to 5.54 ± 0.56 μmol kg⁻¹, silicic acid by up to 28.12 ± 3.98 μmol kg⁻¹ and phosphate by up to 0.61 ± 0.07 μmol kg⁻¹ compared to years of negative SAM. On the other hand, in years of positive ENSO, the concentration of DIN can decrease by up to –3.90 ± 0.86 μmol kg⁻¹, silicic acid by up to –8.95 ± 3.82 μmol kg⁻¹ and phosphate by up to –0.11 ± 0.11 μmol kg⁻¹, compared to years of negative ENSO. Both SAM and ENSO drive changes in macronutrient concentrations through their influence on Dense Shelf Water and Circumpolar Deep Water, water masses that control diverse biogeochemical processes in the Southern Ocean. These findings are fundamental to improving our understanding of the natural variability in macronutrient biogeochemistry and identifying potential changes due to global climate change.

63

Rethinking Antarctica: Artistic Interventions and Ontological Explorations

Dr Alejandra Perez

Universidad de Valparaíso, Valparaíso, Chile

Abstract

In recent years, there has been a growing interest in redefining Antarctica beyond conventional
representations of the sublime and the imperceptible. This presentation is informed by a comprehensive investigation into artistic responses to Antarctica, drawing on interdisciplinary approaches and philosophical frameworks to challenge traditional perceptions of the region. The ”Oceanic Turn” has sparked critical discourse against colonial impositions and disciplinary boundaries, emphasizing the need for nuanced understandings of maritime cultures. Central to this discourse is the concept of the ”Ontology of Ice,” which transcends singular characteristics to encompass biotic, technological, and geophysical dimensions. Building upon Immanuel Kant’s Critique of Judgment, this research in practice, focuses on rendering aesthetic responses to Antarctica beyond normative representations of the sublime and the imperceptible. It is based on a decade of fieldwork in polar and sub-polar areas.
The Kantian concept of the sublime is explained and devised into art works and then tested
through concepts such as translation, transduction, infection and representation, using hacking
methodologies. Technical methods include Free Libre Open Source software, infrared photog-
raphy, sound recordings, and bio-sensing proxies, among others. These methods facilitate a
multi-sensory and multi-dimensional engagement with Antarctic landscapes. Specific outputs of
this investigation include ”Antarctic Sound Cartography”, a series of recordings of Very Low Fre-
quencies recorded in Base Prat, South Greenwich Island in 2009, it also includes ”Sensor Masa” a sensing array of bread dough and micro voltage amplifier to enable access to imperceptible changes in the environment. Through experimental hacking practices, the research supports the hypothesis that Antarctica can be represented beyond the sublime, emphasizing the importance of interrupting conventional spectacles. The significance of artistic interventions in reimagining Antarctica underscores the potential for interdisciplinary collaborations to enrich our understanding of the region by challenging normative representations and embracing comprehensive investigation into the ontological status of Antarctica.

65

Taming a ‘fuzzy beast’? Stakeholder perspectives on Antarctic science-policy knowledge exchange practices in New Zealand

Natasha Gardiner^1,2, Neil Gilbert¹, Daniela Liggett¹

¹Gateway Antarctica, University of Canterbury, Christchurch, New Zealand. ²Antarctica New Zealand, Christchurch, New Zealand

Abstract

Evidence-based decision-making is a core tenet of the Antarctic Treaty System (ATS), which requires multidirectional knowledge exchange (KE) among science and policy actors at multiple scales. However, effectively mobilising and using scientific knowledge within policy and decision-making practices is not always straightforward and there has been a broader shift in discourse away from linear science-policy arrangements, towards co-production alternatives. Studies on the Antarctic science-policy interface to date have largely focused on the international perspective, but the ways in which KE practices are arranged domestically plays an important role in meeting the knowledge, information, management, and governance needs of the various policy bodies of the ATS. While there are formal mechanisms that help to facilitate science-policy interactions at the international scale, the pathways that connect Antarctic research and policy communities domestically are less obvious and uniquely different across the Antarctic Treaty Parties. This presentation shares the findings of a study that aimed to explore domestic stakeholder perspectives regarding Antarctic KE using New Zealand (NZ) as a case study. We convened two workshops involving over 60 NZ Antarctic stakeholders in 2021 that aimed to explore the various elements of NZ’s Antarctic science-policy interface and identify barriers or drivers for success, including future opportunities. Three key themes were identified including (1) a desire to move beyond the linear model towards more collaborative ways of working, (2) an ‘inclusivity-exclusivity’ paradox of an informal social network and small community in NZ, and (3) a need for strengthened domestic policy leadership. This study contributes to our understanding of Antarctic KE practices by shedding light on several important elements that should be considered in any attempts to understand or improve future KE practices in NZ or within the domestic settings of other Antarctic Treaty Parties that are interested in fostering science-policy success.

66

Practitioners’ perspectives on the enablers and barriers to successful Antarctic science-policy knowledge exchange practices

Natasha Gardiner^1,2, Daniela Liggett¹, Neil Gilbert^1,3, Christopher Cvitanovic^4,5

¹Gateway Antarctica, University of Canterbury, Christchurch, New Zealand. ²Antarctica New Zealand, Christchurch, New Zealand. ³Constantia Consulting Limited, Christchurch, New Zealand. ⁴School of Business, University of New South Wales, Canberra, Australia. ⁵Centre for Marine Science and Innovation, University of South Wales, Canberra, Australia

Abstract

Multilateral environmental governance regimes like the Antarctic Treaty System (ATS) are pivotal in addressing today’s wicked transboundary socio-ecological problems and central to their success is the facilitation of constructive knowledge exchange (KE) between research and policymaking communities. Consequently, the literature is now ripe with studies that aim to uncover the elements that drive or hinder KE successes across diverse environmental governance settings. Yet, in the Antarctic context, the KE practices that comprise Antarctic science-policy interfaces (SPI) remain empirically under examined. Here we contribute by exploring the perspectives of 31 Antarctic practitioners to develop our understandings of successful KE practices in the policy contexts of the Antarctic Treaty Consultative Meetings (ATCM) and the Committee for Environmental Protection (CEP). By adopting a reflexive thematic analysis, we identify 11 enablers and 9 barriers to KE success that are overlapping, interconnected and complex. In the face of pervasive barriers, such as the often overshadowing effect of politics, a deficiency of KE incentives and large-scale wicked policy problems, certain Antarctic institutions and practitioners portray strong boundary spanning expertise, which despite the many challenges identified, serves to facilitate KE in support of evidence-informed decision-making. However, the extent to which boundary spanners are influential in their leadership varies and while acknowledging that influential leadership is an important enabler for success, we raise several questions regarding the potentially unexplored assumptions that underpin current KE practices. As Antarctic practitioners share a desire to foster inclusive, iterative and multidirectional science-policy dialogues among other identified improvements, harnessing reflexivity and humility within these processes will be critically important for ensuring that existing asymmetries or inequities are not reinforced under the guise of improved ways of working.

67

Measuring the performance of Antarctic Treaty decision-making

Natasha Gardiner^1,2, Neil Gilbert^1,3, Daniela Liggett¹, Michael Bode^4,5

¹Gateway Antarctica, University of Canterbury, Christchurch, New Zealand. ²Antarctica New Zealand, Christchurch, New Zealand. ³Constantia Consulting Limited, Christchurch, New Zealand. ⁴School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia. ⁵Securing Antarctica's Environmental Future, Brisbane, Australia

Abstract

Agreements reached at the Antarctic Treaty Consultative Meetings (ATCMs) are among the primary means for addressing Antarctic conservation and environmental protection issues. However, contemporary scholars are becoming increasingly critical of how responsive Antarctic decision-making is to pressing environmental challenges in the region. Here, we showcase the use of mixed-methods research approaches to address complex Antarctic governance questions that have implications for biodiversity and conservation outcomes. In doing so, we assess Antarctic Treaty decision-making performance by measuring the rate and diversity of decision-making over the last six decades. Our analyses show that the average number of agreements reached per ATCM have increased over this period. However, while the diversity of Antarctic topics discussed at ATCMs has remained consistently high, the diversity of topics on which legally binding agreements are adopted has significantly declined. Over the last three decades, Antarctic issues – including those of highest priority – are more commonly addressed through non-binding soft law agreements. A range of exogenous and endogenous factors likely contribute to the observed trends, including an expansion of Antarctic Treaty membership, institutional constraints, the complex array of Antarctic governance issues and the shifting dynamics of the prevailing global order. While it is plausible that our findings reflect the natural evolution of a dynamic governance institution that is responding to new pressures, we instead suggest that our results highlight a concerning shift in the nature of decision-making over the Antarctic Treaty System’s (ATS) lifespan. Soft law is beneficial in some cases but its overuse serves to diminish the accountability for, and transparency of, actions taken by the Parties. We conclude that this increasing preference for soft law is misaligned with the rise in human activities and climate change impacts in the region, as well as the Parties’ obligations and commitments as set out by the instruments under the ATS.

73

State dependent ice-sheet resonance under Cenozoic and future climates

Prof. Nicholas Golledge¹, Prof. Richard Levy^2,1, Prof. Tim Naish¹, Prof. Rob McKay¹, Dr. Dan Lowry², Prof. Stephen Meyers³, Dr. Nicholas Sullivan³, Prof. Peter Clark⁴, Dr. Michael Weber⁵, Dr. Georgia Grant²

¹Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ²GNS Science, Lower Hutt, New Zealand. ³University of Wisconsin–Madison, Madison, USA. ⁴College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, USA. ⁵Institute for Geosciences, University of Bonn, Bonn, Germany

Abstract

Inferences of ice-sheet change through geological time rely on paleoenvironmental proxies, such as sea level indicators for ice volume or changes in sedimentary sequences to infer ice margin fluctuations. Yet the accuracy of these inferences depends on the presumed constancy of the generative mechanism. Here we show, using an ensemble of epoch-scale ice sheet simulations, that the directionality of change in ice volume, extent, and calving flux is dependent on the background state of the climate. Supporting our model with geological examples we demonstrate that under cold climate states with strong ocean forcing, such as the Late Pleistocene, ice advanced during cold phases and retreated as the climate warmed. Asymmetric cycles arose as a consequence of solid-Earth feedbacks. However, under warmer states such as the mid-Miocene Climate Optimum, ice sheet growth was instead associated with warmer atmospheric conditions due to increased snowfall, and asymmetry was absent. Transient runs show that when the ice sheet switches from one of these modes to the other, harmonic responses arise at timescales of half the forcing frequency. These findings provide mechanistic explanations for changing periodicity, phasing, and asymmetry of ice sheet responses over million-year timescales, and also suggest that ice sheet behaviour under a future, warmer, climate may be radically different from present.

74

A paradigm shift in Antarctic glaciology?

Prof. Nicholas Golledge¹, Prof. Nancy Bertler^2,1, Prof. Peter Clark³, Dr. Gavin Dunbar¹, Dr. Feng He⁴, Dr. Sally Lau⁵, Prof. Richard Levy^2,1, Dr. Dan Lowry², Prof. Tim Naish¹, Prof. Jan Strugnell⁵, Prof. Eric Wolff⁶

¹Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ²GNS Science, Lower Hutt, New Zealand. ³College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, USA. ⁴Center for Climatic Research, University of Wisconsin-Madison, Madison, USA. ⁵James Cook University, Townsville, Australia. ⁶Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom

Abstract

Nearly forty years ago, geophysical evidence from Antarctica revealed that parts of the ice sheet moved as a result of coupling between glacier ice and deformable sediments beneath it. This 'paradigm shift in glaciology' (Boulton, 1996) led to the now widely-accepted view of Antarctica as a highly responsive component of the Earth system. However, when it comes to reconstructing the geometry of the Antarctic Ice Sheet during periods of the past, models and empirical reconstructions typically conform with another well-accepted but by no means well-tested paradigm: that a smaller-than-present ice sheet must also be associated with smaller-than-present ice shelves. Here we present a model of the Last Interglacial Antarctic Ice Sheet that exhibits an ice geometry at odds with this idea - loss of West Antarctica despite stability of the Filchner-Ronne and Ross ice shelves. This configuration arises from two competing mechanisms. WAIS collapse results from oceanic warming in the Amundsen Sea Embayment that triggers dynamic thinning and grounding-line retreat. However, cooler-than-present water in the Ross and Weddell seas enables persistance of the two ice shelves. Grounded ice is lost, therefore, whilst floating ice is preserved. This unusual configuration seems to go against traditional thinking, but is consistent with geological and genomic evidence of large-scale ice sheet retreat despite ocean/atmosphere temperatures similar to today. It also implies persistent floating ice surrounding ice rises such as Berkner Island in the Weddell Sea and Roosevelt Island in the Ross Sea. Analyses of ice cores from these locations will test the modelled geometry: if the simulated configuration is supported by the available evidence, it advocates for a 'paradigm shift' in which ice shelf and ice sheet response to climatic forcings are decoupled from one another. By implication, predictions of future Antarctic ice sheet change will be less straightforward than some current models imply.

78

Short-term time-series observations of phytoplankton light-absorption and productivity in Prydz Bay, coastal Antarctica

Dr. Sarat Tripathy¹, Dr. Anvita Kerkar², Mr. Sunil Padhi¹, Dr. Sudarsanarao Pandi¹, Dr. Sabu Prabhakaran¹, Dr. Amit Sarkar³

¹National Centre for Polar and Ocean Research (NCPOR), Vasco-Da-Gama, India. ²Portland State University, Portland, USA. ³Kuwait Institute for Scientific Research Centre, Shuwaikh, Kuwait

Abstract

The optical properties of coastal Antarctic waters are complex due to the dynamic hydrography influenced by melt-water intrusion that changes nutrient, thermohaline, and optically active substances (OAS) regimes. Studies on bio-optical variability and its implications on phytoplankton productivity (PP) are scanty in coastal polar regions. On this backdrop, time-series measurements (72h @6h interval) of bio-optical properties such as phytoplankton biomass (chlorophyll-a), absorption (a_ph), and total suspended matter (TSM) concurrently with PP were measured to understand their interplay and variability in relation to the ambient physicochemical settings in the under-sampled Prydz Bay, coastal Antarctica. Results indicated thermohaline stratification in the bay, presumably resulting from the influx of less saline melt-water from the nearby glaciers and low wind activity. The persistent occurrence of sub-surface chlorophyll maximum (SCM) below the stratified layer emphasized the light-acclimatization response of the shade-adapted phytoplankton. Comparatively, more TSM in surface waters than deeper layers indicated glacial melt influence; however, the sunlit depth was relatively stable, indicating less movement of water mass and/or less variability in OAS in the studied location. An inverse relationship between chlorophyll-a and chlorophyll-specific a_ph (a*_ph) manifested the ‘pigment package effect’ in the prevailing phytoplankton community, implying restrained light-absorption efficiency, which leads to lower PP. Compared to chlorophyll-a, the a_ph was a better proxy for explaining PP variability. The absence of nutrient limitation was conducive to micro (large) phytoplankton growth. Phytoplankton size-classes (micro, nano, and pico) derived using the B/R ratio (a_ph at Blue (443 nm)/Red (676 nm) region) confirmed the predominance of larger (micro) phytoplankton that are more susceptible to package effect thereby have implications on reduced PP potential of this polar marine ecosystem.

80

Gains and impacts, or a balance? Exploring spatiotemporal patterns linking scientific and environmental indicators in the greater McMurdo Dry Valleys

T. Kristin Wilson

School for Science in Society, Victoria University of Wellington, Wellington, New Zealand. Te Pūnaha Matatini, Centre of Research Excellence for Complex Systems, Auckland, New Zealand

Abstract

A key challenge on a human-dominated planet is to account for the relationships between people and nature (Pascual et al., 2023; Plumwood, 2002; Schlüter et al., 2020). In Antarctica, the interests of scientific research and environmental protection have been explicitly linked since the adoption of the Protocol on Environmental Protection to the Antarctic Treaty in 1991 (Secretariat of the Antarctic Treaty, 1991). The relationship between these interests is often expressed in two different stewardship goals, as ‘scientific gains versus environmental impacts’ or as a ‘balance’ (for example, Chignell et al., 2021; Hughes et al., 2023). Understanding the relationship between scientific and environmental interests is particularly important in sensitive ice-free areas (Brooks et al., 2019). To better inform sustainable governance goals this interdisciplinary research employs a social-ecological systems approach (Berkes and Folke, 1998; Biggs et al., 2021) to explore the spatiotemporal patterns linking scientific and environmental indicators across the greater McMurdo Dry Valleys region between 1903 and 2022. Three new datasets are used as indicators of scientific and environmental values. These are then characterised, mapped, and compared using statistical and geospatial analyses. This research explores the degree to which the relational definitions of ‘scientific gains versus environmental impacts’ or ‘balance’ can be empirically observed in the landscape of the Dry Valleys and how these indicators align with explicit environmental values held in Antarctica (Secretariat of the Antarctic Treaty, 1991). By adopting a complex systems based sustainability approach (Biggs et al., 2021), this research joins two approaches, science of science and human footprint, which are typically investigated in isolation (for example, Ji et al., 2014; Leihy et al., 2020) and contributes to addressing the under-representation of Antarctica in the field of social-ecological systems research (De Vos et al., 2019).

81

Twenty-thousand-year lag between deglaciation and peat formation on sub-Antarctic Marion Island attributed to climate and sea level change

Prof Werner Nel¹, Prof Dominic Hodgson², Prof David Hedding³, Dr Alex Whittle², Dr Elizabeth Rudolph⁴

¹University of Fort Hare, Alice, South Africa. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of South Africa, Johannesburg, South Africa. ⁴University of the Free State, Bloemfontein, South Africa

Abstract

Radiocarbon dating of basal peats has been a key factor in determining minimum ages for deglaciation on sub-Antarctic islands. On Marion Island, peat bogs dominate the landscape below 300 m.a.s.l., and palynological assessments of peat cores have been used to assess the vegetation history and succession rates as well as the sensitivity of the indigenous flora to climatic change. Initiation of peat on the sub-Antarctic islands signifies a major landscape change which has previously been linked to the retreat of glaciers. Here we test this hypothesis by comparing previously published and new basal peat ages from Marion Island with cosmogenic isotope dates for deglaciation, and local and regional palaeo-environmental changes. Results show that, in common with other sub-Antarctic islands, peat initiation occurred after the Antarctic Cold Reversal (15-13 ka) and through the early Holocene climate optimum. This substantially post-dates cosmogenic isotope evidence for deglaciation which shows that the areas where the peatlands dominate were ice-free from the start of MIS 2 (~31 ka). This suggests that environmental conditions controlled peat initiation rather than deglaciation. Regional climatic proxies show that during and after MIS 2, extremely low temperatures, extensive sea ice conditions and depressed sea surface temperatures together with lower sea levels at an island scale could have maintained conditions unfavourable for peat initiation at their current locations. On Marion Island, the significant lag of ~20k years between the timing of deglaciation and peat formation indicate that the use of peat basal ages as a proxy for the minimum age of deglaciation in the sub-Antarctic should be used with extreme caution.

85

Links between large-scale circulation variability and coastal polynya dynamics in the Ross Sea sector during Winter

Ms Girija Kalyani Burada¹, Dr James Renwick¹, Dr Adrian McDonald²

¹Victoria University of Wellington, Wellington, New Zealand. ²University of Canterbury, Christchurch, New Zealand

Abstract

Ross Sea coastal polynya variability in winter is identified in an EOF analysis of high-resolution passive microwave estimates of sea-ice concentration. Observed patterns of sea-ice variations are related to surface regional extreme winds from the ERA5 reanalysis to understand local effects and to 500hPa geopotential heights to capture relationships with the large-scale hemispheric flow. We find the local Ross Sea extreme winds are strongly linked to the extra-tropical atmospheric circulation. Each of the three polynyas in the region (Ross Sea, Terra Nova Bay, and McMurdo Sound) responds differently to the position of large-scale circulation patterns. There is evidence of increases/decreases in the polynya area associated with specific modes, particularly the Amundsen Sea Low and changes in the Ross Ice Shelf Air Stream wind patterns. These findings provide a causal pathway between large-scale modes and their modulation of small-scale sea-ice processes within the various polynya.

88

Who speaks for the ice? News representations of Antarctica matter.

Linda Hunt

University of Tasmania, Hobart, Australia

Abstract

There are many ways of knowing and understanding Antarctica from afar, as has been shown in previous scholarship in the humanities and social sciences (Nielsen & Philpott 2018; Roberts, Howkins & Watt 2016). The threat of climate change and growing geopolitical tension have reinvigorated public and media interest in the continent. But the role of news media in public engagement with the Antarctica has been largely overlooked. This is a significant gap in research about a critical global location. News media play a crucial role in constructing social and environmental issues (Couldry and Hepp 2008, Hansen 2015), and news is the public’s main source of scientific information (Jamieson, Kahan & Scheufele 2017; Rose Guenther & Froehlich 2016). This news coverage does not happen in a vacuum – there are political, social, cultural, and economic factors at play. News reporting about Antarctica is made more challenging because of its geographical isolation and the logistics involved in travelling to the site where news is happening. The influence of news media in public engagement with Antarctica is a key concern, as is the content of news stories. My research into Australian news representations of the continent has shown that science is not the driver of public engagement. Instead, the experiences of Australians working in Antarctica, and the infrastructure that supports them, is the focus of news stories. Heroic era tropes of brave and adventurous expeditioners persist, and Antarctica is predominantly framed as an occupied territory rather than a fragile, threatened continent. This paper argues for greater consideration of news media’s role in communicating the continent and the threats it faces, along with further examination of the cultural and structural challenges faced by news media to tell the most pressing stories about Antarctica and its role in the fate of the planet.

93

Study of the year-round thermohaline evolution along and beneath the Ross Ice Shelf using Argo floats.

Prof. Pierpaolo Falco¹, Dr. Naomi Krauzig¹, Dr. Pasquale Castagno², Dr. Angela Garzia^3,1, Dr. Riccardo Martellucci⁴, Prof. Yuri Cotroneo⁵, Dr. Daniela Flocco⁶, Dr. Milena Menna⁴, Dr. Annunziata Pirro⁴, Dr. Elena Mauri⁴, Dr. Francesco Memmola¹, Dr. Cosimo Solidoro⁴, Dr. Massimo Pacciaroni⁴, Dr. Giulio Notarstefano⁴, Prof. Giorgio Budillon⁵, Prof. Enrico Zambianchi⁵

¹Marche Polytechnic University of Ancona, Ancona, Italy. ²University of Messina, Messina, Italy. ³Sapienza University, Rome, Italy. ⁴National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ⁵Parthenope University, Naples, Italy. ⁶Univesity of Naples Federico II, Naples, Italy

Abstract

The Ross Ice Shelf (RIS) floats above the southern sector of the Ross Sea, creating a cavity that is critical for ocean-ice interactions. This area is characterised by the formation of Ice Shelf Water (ISW), the coldest ocean water mass, and the intrusion of Antarctic Surface Water, the main driver of frontal melting and ice shelf calving, the predominant cause of ice shelf thinning and ice discharge, which directly affects global sea level.

In this presentation we will show unprecedented thermohaline observations from unconventionally programmed Argo floats deployed along the RIS front in the austral summer from 2020 to 2023.

Their measurements provided the first year-round observations of water column changes in crucial areas of the RIS, such as the polynya. We estimated a volume of 0.1 to 0.4 Sv of High Salinity Shelf Water, precursor of the ISW and the Antarctic Bottom Water. From temperature and salinity profiles we calculated the ocean heat content (on average 5x108 Jm-2), the basal melt rate (ranging between 0.6 and 1.6 m) and finally the freshwater content (summer values up to 10 cm). Taken together, these measurements point to crucial phenomena, some of them only described in theory.

94

15 Years’ Presence of the Non-Native Fly Trichocera maculipennis in Antarctica: Current Insights and Future Prospects

Dr. Hugo Benitez^1,2,3, Dr. Tamara Contador^1,3, Dr. Katarzyna Tołkacz⁴, Dr. Sanghee Kim⁵, Dr. Mónica Remedios-De León⁶, Dr. Claudia Maturana^1,3, Mr. Jordan Hernandez^7,1,2, Ms. Melisa Gañán^1,3, Dr. Peter Convey^8,1,9,3

¹Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ²Universidad Católica del Maule, Talca, Chile. ³Cape Horn International Center (CHIC), Puerto Williams, Chile. ⁴Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. ⁵Division of Life Sciences, Korea Polar Research Institute, Incheon, Korea, Republic of. ⁶Entomology Section, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ⁷Cape Horn International Center (CHIC), Santiago, Chile. ⁸British Antarctic Survey (BAS), Natural Environment Research Council, Cambridge, United Kingdom. ⁹Department of Zoology, University of Johannesburg, Auckland Park, South Africa

Abstract

The presence of non-native invasive species is impacting ecosystems globally, including the remote islands surrounding Antarctica and the fringes of the continent itself. Members of the dipteran genus Trichocera are widespread in the Northern Hemisphere, particularly in boreal regions. Two members of the genus are established in parts of Antarctica with the first, T. regalationis, probably introduced to sub-Antarctic South Georgia during the whaling era of the early twentieth century. The second, T. maculipennis, has also been established on the sub-Antarctic Kerguelen archipelago for many years, but the first publication recording its presence in maritime Antarctica was in 2013, reporting records of the species on King George Island, between the first observation of an isolated individual in 2006 near the Chilean airfield Frei followed by its repeated establishment in the sewage system of the Uruguayan Artigas Station. Despite several eradication efforts, T. maculipennis is still present in various stations and in surrounding natural habitats and is also now known to have colonized Puerto Williams on the Magellanic sub-Antarctic Navarino Island. Recently, a consortium of researchers from the Millenium Institute of Antarctic and Subantarctic Biodiversity, Instituto Antártico Chileno, Instituto Antártico Uruguayo, the Institute of Biochemistry and Biophysics of Polish Academy of Sciences, South Korean polar research institute and the British Antarctic Survey have developed a research plan to investigate the pattern of genetic, genomic and morphometric adaptations of these flies that may have facilitated their invasion of the South Shetland Islands and also shape their future trajectory and ecosystem impacts in Antarctica. In this presentation we review the current state of knowledge and discuss likely future developments in this terrestrial invasion, highlighting lessons and future research priorities required to at least minimize future spread of the species beyond its already wide distribution on the ice-free peninsulas of King George Island.

95

How much plastic is in the air? A quantitative intercomparison of common microplastic analysis methods and new observations from Northern Victoria Land

Alex Aves¹, Anna MacDonald², Sebastian Naeher³, Dusan Materic⁴, Holly Winton⁵, Deonie Allen², Perry Davy³, Sally Gaw¹, Laura Revell¹

¹School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand. ²Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, United Kingdom. ³GNS Science, Lower Hutt, New Zealand. ⁴Department of Analytical Chemistry, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany. ⁵Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand

Abstract

Microplastics are an emerging contaminant of concern that are widespread in the environment, including remote places such as Antarctica. The presence of microplastics in the air presents new challenges to understand their movement through and between environmental matrices and the potential impacts on ecosystem health. While the number of studies reporting airborne microplastics is rapidly increasing, a lack of standardised methods is apparent. Comparing different studies to understand the global microplastic distribution is difficult and, in some cases, impossible due to differences in sampling methodology and analysis, which may result in largely different estimates of microplastics in the environment. Here we present an inter-laboratory comparison which was undertaken to understand the uncertainties and errors associated with common analytical methods for measuring airborne microplastics. A set of samples collected using a high-volume air sampler were analysed by micro-Fourier transform infrared spectroscopy (µFTIR), micro-Raman spectroscopy (µRaman), fluorescence microscopy, pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and thermal desorption – proton transfer reaction – mass spectrometry (TD-PTR-MS). The findings inform how future airborne microplastic studies using different analytical methods should be interpreted, and this knowledge has then been applied to snow and air samples collected from Northern Victoria Land, Antarctica. The findings further our understanding of microplastic abundance, movement and accumulation in the Antarctic and the potential exposure of these unique ecosystems.

96

Understanding the Role of Atmospheric Drivers in the Unprecedented Antarctic Sea Ice Loss of February 2022

Ms Juhi Yadav^1,2, Dr Avinash Kumar¹, Dr Rahul Mohan¹

¹National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco-da-Gama, Goa, India. ²Department of Marine Geology, Mangalore University, Mangalore, India

Abstract

The expansion and recession of sea ice in the Antarctic exhibit regional and temporal asymmetries. While sea ice extent (SIE) experienced a decade-long increase until 2015, recent years have shown a decline in SIE since satellite records began. This study aims to investigate the atmospheric drivers and climate fluctuations behind the lowest SIE record observed in February 2022. The study assumes that this record low resulted from shifts in atmospheric patterns that began in September 2021. In February 2022, there was a marked historic low of 2.16 × 10⁶ km², 43% below the mean extent of previous February months in the satellite era. However, the second-lowest SIE occurred from November 2021 to January 2022. The regional analyses highlight significant sea ice changes in the Weddell Sea, Ross Sea, and Bellingshausen/Amundsen Seas (ABS) sectors. The record-low SIE can be attributed to the intensified Amundsen Sea Low (ASL) pressure center and the positive phase of the Southern Annular Mode (SAM), which altered pressure and wind patterns across Antarctica. Warm northerly winds predominated in regions contributing to decreased SIE, while wind-driven sea ice drift towards the north led to increased sea ice elsewhere. Additionally, this study analyzed the Polar Cap Height (PCH), indicating the strength of the stratospheric polar vortex and the polarity of SAM. This study provides valuable insights for comprehending the dynamics for Antarctic sea ice recession, thereby contributing to a deeper understanding of their broader impact on global climate patterns.

102

Modelling the age-depth relationship and basal conditions using radar horizons at Dome C

Ailsa Chung¹, Frédéric Parrenin¹, Robert Mulvaney², Luca Vittuari³, Massimo Frezzotti⁴, Antonio Zanutta³, Olaf Eisen^5,6

¹Université Grenoble Alpes, Grenoble, France. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Bologna, Bologna, Italy. ⁴University Roma Tre, Rome, Italy. ⁵Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Bremerhaven, Germany. ⁶Universität Bremen, Bremen, Germany

Abstract

The Beyond EPICA - Oldest Ice project aims to extract an ice core which contains a paleoclimatic record covering the past 1.5 Ma from Little Dome C in Antarctica. While searching for a suitable drill site, multiple radar surveys were conducted in the Dome C region. We have developed a 2.5D flow model that is constrained by horizons traced in these surveys. We interpolate and extrapolate the age-depth relationship using these horizons to investigate the Beyond EPICA drill site and surrounding areas.

The simplicity of our 2.5D numerical integration scheme results in an efficient computation time allowing us to use inverse methods to determine an average accumulation rate over the past 800 ka, a mechanical ice thickness and the Lliboutry thinning parameter which describes the shape of vertical velocity profile. The inverted mechanical ice thickness allows us to infer either a basal melt rate or the thickness of a layer of stagnant basal ice.

The model shows that the EDC-LDC flow line is dominated by melting on in the upstream sections, and further downstream, there is a thick layer of stagnant ice over the LDC mountainous bedrock relief. Our results show to what extent the Beyond EPICA - Oldest Ice drill site is affected by horizontal flow from upstream at the dome and the implications for the age-depth profile of the ice core currently being drilled. The deepest, oldest ice at the drill site, comes from 10-15 km upstream. However, the differences between the model and observations cannot be fully explained by horizontal flow. This model approach could be readily applied to other areas of Antarctica using internal ice sheet structure radar data collected by the AntArchitecture SCAR action group.

105

Anthropology's Lens on Health and Well-being in Isolated and Confined Extreme Environments: Insights from Antarctica and Beyond

Dr Susie Pottier

University of Western Australia, Perth, Australia

Abstract

Until now, studies on well-being, adaptation, and the impact of isolation on interpersonal relations and group dynamics in Antarctica have primarily been conducted by physicians, psychologists, or psychiatrists. This presentation aims to delineate the potential contributions of anthropology, both fundamental and applied, to understanding and enhancing the lived experiences, social structures, and health outcomes of individuals in these extraordinary landscapes.

This discussion delves into diverse anthropological dimensions, such as the impact of cultural diversity, hierarchical relationships, and ceremonial practices on the psychological examination of human responses, adaptability, and well-being within isolated and confined environments, such as Antarctica and outer space. Specifically, our study centers on the winter crew stationed in Adélie Land (TA70), complemented by valuable insights gathered from former winterers at Dumont d’Urville and other research stations.

In the multidisciplinary effort made by scientists to gain a more holistic approach to human on the White Continent, the various branches of anthropology offer distinctive contributions to medical science. Social anthropology provides insights into socio-cultural factors related to the environment or physical/psychological symptoms, while the anthropology of science facilitates the examination of medical practices, including medical management, ethical considerations, and the utilization of innovative approaches.

By bridging disciplines and perspectives, this research seeks to not only shed light on the intricate dynamics of human life in extreme environments but also to propose actionable strategies for enhancing the well-being and resilience of individuals and communities in these challenging conditions.

106

"Monographs Are Outdated": Bridging Past and Future Through the Exploration of New Methodological Frontiers and Anthropological Paradigm Shifts in Antarctica

Dr Susie Pottier

University of Western Australia, Perth, Australia

Abstract

Scientists engaged in Antarctic research, whether in the life sciences, glaciology, or the social sciences, face challengses between the long process of access to fieldwork and its rapidly evolving nature. The ice is melting, numerous species face extinction threats, while the realm of individuals engaged in art, tourism, public engagement, and research stations continues to expand. This presentation examines the challenges of scientific conception and production, emphasizing the need for innovative methodologies through the lens of social anthropology.

This article aims to explore the relevance of tools such as monographs or long-term ethnography, whose applications are often hindered by the remoteness and isolation of the field. Additionally, it investigates new paradigms that hold promise for the anthropology of the future and new ways of living in an increasingly extreme climate. The convergence of past and future presents an opportunity to contemplate the possibilities within interdisciplinary realms and foster participatory research encompassing not only various scientific domains but also individuals directly impacted, residing and working within the stations and beyond.

Drawing from extensive fieldwork experiences, as well as numerous discussions with people closely or remotely involved with the White Continent, this article proposes several approaches to the future of the social sciences in Antarctica, reflecting on the inclusivity, applicability, and responsibility of researchers towards this icy changing environment.

109

Traveling Ionsopheric disturbances origin and propagation observed by GPS dTEC maps: case study of global ionosphere electrodynamics during geomagnetically disturbed periods.

Mr Chukwuma Anoruo¹, Prof Yuichi Otsuka², Prof Nneka Okeke¹, Prof Chukwudi Okpala¹

¹University of Nigeria, Enugu, Nigeria. ²Nagoya University, Nagoya, Japan

Abstract

Travelling Ionospheric Disturbances (TIDs) are the ionospheric manifestation of internal Atmospheric Gravity Waves (AGWs), detected as plasma density ﬂuctuations that propagate through the ionosphere with velocities and amplitudes that could depend on the source. This study expand the understanding of the dominant global-energy distribution and momentum transfer mechanisms in the ionosphere and thermosphere due to LSTIDs, and systems that rely on models based predictions of ionospheric radio-wave propagation physics. We employ threshold criteria for amplitude oscillation > 0.1 TECU, horizontal wavelength > 1000 Km, period of oscillation > 30 min, and horizontal phase velocity > 300 m/s to analyze 23, April 2012; 19, February 2014 and 17, March 2015 geomagnetic storms derived from global GNSS of GEONET. To determine the horizontal phase velocity and propagation direction of LSTIDs, we employ TEC as function of time and horizontal distance in the meridional and zonal directions (keogram), and considering time series of global dTEC maps at 5 min intervals. We observe LSTIDs from 14 h UT to 20 h UT on 17 March with speed of 524 m/s and with wavelength of 1218 Km in the American sector, showing a time difference in the Brazilian sector and does not seem to appear in other sectors during the global-energy distribution and therefore experience damping when crossing to other sectors. Also, the propagation and features of LSTIDs in most cases seem not to depend strongly on storms.

Keywords: TID, global energy input, horizontal distance, GNSS

110

Multi-year variation of near-surface ozone at Zhongshan Station, Antarctica

Biao Tian¹, Minghu Ding¹, Davide Putero², Chuanjin Li³, Dongqi Zhang¹, Jie Tang¹, Xiangdong Zheng¹, Lingen Bian¹, Cunde Xiao⁴

¹Chinese Academy of Meteorological Sciences, Beijing, China. ²National Research Council of Italy, Turin, Italy. ³State Key Laboratory of Cryospheric Science, Lanzhou, China. ⁴Beijing Normal University, Beijing, China

Abstract

With the support of the Chinese National Antarctic Research Expedition, near-surface ozone (O₃) was continuously monitored at Zhongshan Station (ZOS) (69◦ 22′ 12′′ S, 76◦ 21′ 49′′ E, 18.5 m above sea level) in East Antarctica from 2008 to 2020. The seasonal and diurnal variability of near-surface O₃ at ZOS were investigated. O₃ enhancement events (OEEs) were frequently observed in the warm season (OEEs in January accounted for 23.0% of all OEEs). The OEEs at ZOS were related to the photochemical reaction processes under the influences of O₃ and solar radiation in the stratosphere and synoptic-scale air mass transport from coastal areas (Princess Elizabeth Land, Wilkes Land, and Queen Mary Land), as evidenced by the recorded wind speed, solar shortwave irradiance, and total column ozone data and the computed potential source contribution function and concentration-weighted trajectory models. The results computed by the tool Stratosphere-to-Troposphere Exchange Flux indicated that stratosphere-to-troposphere transport had no direct impact on OEEs at ZOS. Therefore, synoptic-scale air mass transport is the main cause of OEEs in Antarctica, which is consistent with previous studies. Unlike OEEs at inland Antarctic stations, which are mainly affected by air mass transport from inland plateaus, OEEs at ZOS, a coastal station, are mainly affected by air mass transport from coastal land in East Antarctica.

117

Extreme warm events in the South Orkney Islands, Southern Ocean: Compounding influence of atmospheric rivers and föhn conditions

Dr Hua Lu, Dr Andrew Orr, Prof. John King, Mr Tony Phillips, Dr Ella Gilbert, Mr Steve Colware, Dr Thomas Bracegirdle

British Antarctic Survey, Cambridge, United Kingdom

Abstract

Extreme warm events in the South Orkney Islands (SOIs) are investigated using synoptic observations from Signy and Orcadas stations for 1947–1994 and 1956–2019 respectively. Defining the extremes as temperatures exceeding the 95th percentile of the temperature distribution, we reveal the characteristics and associated drivers of the warm events, especially the top 10 events in both summer and winter. At both stations, extreme warm events often involve a combined effect of atmospheric rivers (ARs) and localised föhn warming, with distinct characteristics due to the station locations relative to Coronation Island, the largest and highest island of the SOIs. For example, warm events at Signy are warmer (by an average of around 3°C) than the corresponding concurrent temperatures at Orcadas. The number of warm events per year has significantly increased over the record periods at both stations, which could potentially impact ecosystems by increasing melting of snow and ice. Extreme warm events at Signy are dominated by föhn warming in combination with ARs originating from the Southern Atlantic Ocean, where warm, moisture-rich air is rapidly advected towards the islands by enhanced northerly winds. By contrast, the Orcadas warm extremes involve both warm-air advection and föhn warming associated with enhanced northwesterlies/westerlies with ARs originating in the Pacific Ocean that travel across the Drake Passage. Simulation of one of the top 10 warm events for Signy station using a 1-km grid spacing configuration of the atmosphere-only UK Met Office Unified Model is used to disentangle the role of local versus large-scale forcing. We find that the majority of the warming can be attributed to föhn effects for the case study. These results demonstrate the complexity of Antarctic temperature extremes.

118

Developing a 3D Virtual Museum for Non-Formal Education

Silvia Dotta¹, Sandra Freiberger-Affonso¹, Fabiana Costa¹, Juliana Braga¹, Monica Petti²

¹Federal University of ABC, Santo André, Brazil. ²Oceanographic Institute of University of São Paulo, São Paulo, Brazil

Abstract

Museums play a crucial role in the dissemination of scientific knowledge and non-formal education. However, they require a significant investment for maintenance and operation. Despite numerous collections of biotic and non-biotic materials existing in Brazilian research institutions, these resources are often inaccessible to the public. Therefore, we started the development of a 3D virtual museum with the main objective of democratizing access to a collection of Antarctic marine organisms housed at the Oceanographic Institute of the University of São Paulo (ColBIO). This collection has specimens of animals sampled since the first Brazilian Antarctic Expedition in 1982/83. The first version of the museum will showcase 18 animals from a simplified Antarctic food, encompassing phytoplankton, invertebrates, fishes, birds, and mammals. The chosen theme, "trophic web", was selected to make the museum useful by teachers across various levels, favouring the reuse of the 3D objects produced. This study details the construction process of the virtual museum employing methodologies for 3D object production. The 3D Virtual Museum on Antarctic Sciences will provide two access options: the first allows users to download and 3D print the objects, while the second offers online interactive access. Through the latter, users can manipulate objects, rotating them along all directions of the XYZ axis. Antarctic animal models were created using sculpt modelling and photogrammetry. A comparative analysis of the processes revealed insights into production time, required resources, technical and artistic knowledge, software usability, results precision, and each method's scalability and malleability. As a result, we concluded that combining sculpt modelling – a slower process demanding artistic and technical knowledge – with photogrammetry – a faster and easier method to apply – favour large-scale production.

120

The shift of sea ice mass balance in the Ross Sea caused by atmospheric forcings

Hongjie Xie¹, Younghyun Koo², Stephen Ackley¹

¹University of Texas at San Antonio, San Antonio, USA. ²Lehigh University, Bethlehem, USA

Abstract

In the austral summers of 2022 and 2023, the Antarctic sea ice extent (SIE) recorded historic minimums in a row, followed by exceptionally low SIE during the corresponding autumns and winters. Although the recent warming in the Southern Oceans is primarily responsible for such negative anomalies of SIE, anomalous atmospheric circulation events can also play a role, particularly in the Ross Sea and Bellingshausen/Amundsen Seas (ABS), with the occurrence of the intensified Amundsen Sea Low (ASL). Besides the changing SIE, such atmospheric anomaly events could also cause the re-distribution of ice thickness and sea ice deformation (i.e., formation of pressure ridges). Therefore, we examine the spatiotemporal changes in the sea ice thickness and sea ice deformation in the Ross Sea from 2019 to 2023 using NASA’s ICESat-2 satellite altimeter data. The ice thickness of level ice, surface roughness, and areal fraction of pressure ridges are all retrieved from the ICESat-2 ATL10 sea ice product and compared for different years. We find that there was a significant transition of sea ice mass balance in the Ross Sea from 2019-2020 to 2021-2023: (1) the inflow of thick ice from the Amundsen Sea to the Ross Sea has dramatically decreased in the period of 2021-2023; (2) sea ice in the eastern Ross Sea was less deformed in the same period. The strong ASL circulation in spring could have driven such an abrupt shift of sea ice thickness distribution in the Ross Sea. This implies that ICESat-2 data analysis on the changing sea ice and pattern would provide critical information to better understand the coupled atmosphere-ocean-sea ice systems and dynamics.

124

Retrospective modelling of air impacts in Antarctica: a case study Larsemann Hills

Prof. Sergey Kakareka, Dr. Sviatlana Salivonchyk

Institute for Nature Management of the National Academy of Sciences of Belarus, Minsk, Belarus

Abstract

In the late 19^th and early 20^th centuries, construction of the first stations began in Antarctica. This process accelerated during the International Geophysical Year (1957/1958). Currently, about 70 year-round and seasonal stations from 29 countries operate in Antarctica. Human impact on the natural environment of Antarctica may seem insignificant in absolute terms compared to levels in more inhabited areas of the Earth; however, given the extreme sensitivity and vulnerability of Antarctic natural systems, its levels may exceed acceptable (critical) thresholds. But quantitative assessment of levels and trends of anthropogenic impact levels due to operations in Antarctica are scarce.

The presentation is devoted to the assessment of atmospheric air impacts in the oases of the Larsemann Hills, East Antarctica. The performed studies made it possible for the first time to estimate the emission of pollutants from the operation of diesel generator sets from all scientific stations located in the Larsemann Hills during the period of development of the oasis, starting from the construction of the first scientific station in 1986. It is shown that SO₂ emissions decreased significantly in 2019 compared to peak values in 1990, which was due to a significant decrease of the sulfur content in fuel. Surface air pollution by SO₂, NO₂, CO, PM₁₀ and black carbon (BC) using the AERMOD dispersion model are characterized. It is revealed that the most significant emission health impact is due to increase of surface concentrations of NO₂. Deposition fluxes of PM₁₀ and BC are estimated. Modeling of BC deposition allowed to make draft estimates of soot concentration in the snow of the area and resulting radiative forcing climatic effects.

Proposed approaches can be used to assess the cumulative impacts of ongoing and planned activities on the environment in the Antarctic Treaty area.

126

Widening participation in Polar Science: The Diversity in UK Polar Science Initiative (DiPSI)

Mx Pilvi Saarikoski¹, Dr Huw Griffiths¹, Dr Beatrix Schlarb-Ridley¹, Dr Sammie Buzzard², Professor Martin Siegert³, Jane Rumble⁴

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of Northumbria, Newcastle upon Tyne, United Kingdom. ³University of Exeter, Exeter, United Kingdom. ⁴Foreign, Commonwealth & Development Office, London, United Kingdom

Abstract

For almost 200 years since its discovery, visitors to Antarctica were overwhelmingly white men. The Diversity in UK Polar Science Initiative was conceived and funded by the UK Foreign, Commonwealth and Development Office (FCDO) Polar Regions Department. Starting from a position of relative ignorance in terms of the demographics and experience of minorities within the UK polar science community, DiPSI set about quantifying the makeup of the existing community, identifying underrepresentation of ethnic minorities, disabled people and the LGBTQIA+ community. The ambition for this initiative has been to deliver a more diverse and inclusive future for UK polar science – a future that reflects the diversity in British society today. To work towards this, the initiative had planned key areas of impact with projects, advocating engagement across the UK polar community to encourage conversations around present culture and values and to highlight the need for action to address the lack of diversity.

DiPSI established a wide range of products including the flagship Polar Horizons programme, an EDI 101 training programme, targeted work experience and paid internship opportunities, a community guide on inclusive behaviours, race and socioeconomic background impact surveys, online seminar programme, and a calendar of polar interest and inclusion dates. DiPSI serves as an example of what can be done with cross-organisational leadership and suitable investment of time and money to address inherited inequality, whilst emphasising that short term measures do not equate to long term progress.

129

Glacier chronologies for Marine Isotopic Stages 3 and 2 from the southern Indian Ocean: evidence from ³⁶Cl CRE dating on the Kerguelen and Marion islands

Dr Elizabeth Rudolph¹, Ms Joanna Charton², Prof David Hedding³, Prof Vincent Jomelli², Prof Werner Nel⁴, Dr Irene Schimmelpfennig², Dr Deborah Verfaillie²

¹Afromontane Research Unit, Department of Geography, University of the Free State, Bloemfontein, South Africa. ²Aix Marseille Université, Aix-en-Provence, France. ³University of South Africa, Florida, South Africa. ⁴University of Fort Hare, Alice, South Africa

Abstract

It is increasingly apparent that there is variability across the Southern Hemisphere in the nature and timing of glaciations throughout the Quaternary. The sub-Antarctic islands and their terrestrial records are particularly useful to constrain glacial oscillations across the Southern Ocean and provide insight into regional palaeo-climate change. We provide a regional summary for the southern Indian Ocean from glacial histories at the Kerguelen Archipelago (49°S; 69°E) and Marion Island (46°S; 37°E). We use 91 ³⁶Cl cosmic-ray exposure ages from moraine boulders, erratics and bedrock samples to reconstruct a consolidated chronology for Marine Isotopic Stages 3 and 2 with ages spanning from ~63 ka to 17 ka ago. Preliminary moraine ages from Marion Island suggest glacier culminations at ~60.6 ka and ~51.4 ka. While evidence for these advances is still absent from Kerguelen, a synchronous glacier culmination is observed at ~42 ka on both islands. This implies that the more extensive ice limits may have been reached at the transition between MIS 4 (~70-60 ka) and MIS 3 (~60-27 ka), and at the very beginning of the MIS 3 period. On both islands bedrock (~48 ka-17 ka) and erratic exposure ages (~63 ka-20 ka) are used to interpret synchronous periods of slow, continuous deglaciation with intermittent ice stand stills. The retreat pattern continuous throughout the global LGM (26.5-19 ka) except for two localities on Kerguelen showing culminations at ~21 ka and 19 ka. Similar culminations are not found on Marion. We recognize SSTs, sea ice extent and the latitudinal position of the Southern Westerly Wind belt and oceanic fronts as key drivers of the region’s climate. Additionally, we hypothesize that local physiographic and topographic factors significantly control equilibrium line altitudes and, thus, ice accumulation due to their influence on air temperature and precipitation regimes.

131

A Robust Energy Advising System Leveraging Machine Learning in Antarctica

Dr Natasha Nigar¹, Dr Muhammad Kashif Shahzad²

¹University of Engineering and Technology, Lahore, Pakistan. ²Power Information Technology Company, Lahore, Pakistan

Abstract

Antarctica's harsh and remote environment necessitates innovative approaches to energy management to ensure sustainability and efficiency. This research introduces a pioneering energy advising system designed for Antarctica, incorporating machine learning algorithms to optimize energy consumption in extreme conditions. The system utilizes load forecasting to enhance the efficiency of energy infrastructure. By continuously learning from historical data and real-time conditions, the proposed system provides dynamic insights and recommendations for optimal energy usage. The results show that Random Forest accurately predicts energy consumption. The application of machine learning in this context aims to address the unique challenges of Antarctica, contributing to a more sustainable and resilient energy ecosystem in this hard and environmentally sensitive region.

134

Protecting Antarctica’s terrestrial biodiversity: Assessing the coverage of McMurdo Dry Valley’s freshwater ecosystems in the protected area network

Anna Wright¹, Dr. Cassandra Brooks¹, Dr. Adrian Howkins², Dr. Stephen Chignell³, Dr. Michael Gooseff¹

¹University of Colorado, Boulder, USA. ²University of Bristol, Bristol, United Kingdom. ³University of British Columbia, Vancouver, Canada

Abstract

The McMurdo Dry Valleys (MDV), Antarctica’s largest ice-free region, hosts unique terrestrial Antarctic ecosystems, with biodiversity habitats concentrated in the aquatic environments and surrounding soils. Despite this region being a hub of scientific activity, management of the MDV and the creation of the MDV Antarctica Specially Managed Area (ASMA) in 2004 by the U.S. and New Zealand, along with the 1991 Protocol on Environmental Protection to the Antarctic Treaty, have been largely successful in protecting the environment from impacts of human presence. Today, with long-term human presence within the MDV, increasing human activity across the continent, and freshwater ecosystems being subject to environmental change that may affect important biodiversity habitat, the effectiveness of current protections needs to be examined within the context of biodiversity conservation. This study uses a geospatial analysis of MDV current protected areas, streams and lakes, research camps, and tourist sites to assess how the current protections will likely hold against future threats, identify under-protected areas, and outline steps and needs for future protection of biodiversity habitat. Within the MDV ASMA there are five smaller Antarctic Specially Protected Areas (ASPAs). Only one ASPA contains a lake: ASPA 123 Barwick and Balham Valleys, and only two contain streams: ASPA 123 Barwick and Balham Valleys and ASPA 131 Canada Glacier. No ASPAs are designated or managed for the ASPA value of “representative examples of major terrestrial, including glacial and aquatic, ecosystems”, and with <2% of streams protected and <7% of lakes and ponds protected by additional measures beyond those included in the 1991 Protocol on Environmental Protection, the MDV region falls short of the global goals for freshwater protection. Amongst calls for expansion and restructuring of the ASPA network, the MDV has the opportunity to be at the forefront again and increase the protection of Antarctic freshwater ecosystems.

136

Soil Biological and Biogeochemical Changes During Succession after Glacial Retreat

Dr. Becky Ball¹, Dr. Angelica Casanova Katny², Dr. Sarah Eppley³, Dr. Hannah Prather⁴, Dr. Todd Rosenstiel³, Zoie Yetley³

¹Arizona State University, Phoenix, USA. ²Temuco Catholic University, Temuco, Chile. ³Portland State University, Portland, USA. ⁴Reed University, Portland, USA

Abstract

Glacier retreat resulting from climate change is leading to expansion of ice-free areas in Antarctica. This is particularly true in the South Shetland Islands of the Antarctic Peninsula, which has experienced rapid warming over recent decades. Primary succession occurs in these newly exposed areas as vegetation establishes, ultimately driving future soil community structure and biogeochemical processes. Despite advances in understanding plant-soil interactions in the Arctic, the mechanisms of primary succession in terrestrial Antarctica are poorly understood. To explore how inter-specific variation in plant functional types influences soil biogeochemistry, soil functioning, and soil communities in Antarctica, we are measuring the plant-soil relationships during glacial retreat and vegetative expansion on the Antarctic Peninsula. We will share results from a combination of (1) chronosequence transects from receding glaciers; (2) a manipulative transplant experiment; and (3) a geographic survey of plant-soil samples along the Antarctic Peninsula. We demonstrate how pioneer vegetative species arriving in early-succession sites begin to alter the soil microbial and invertebrate community and associated biogeochemical properties and soil CO₂ flux. We also describe the role of keystone late-succession species to significantly increase biological abundance and associated flux rates. Understanding these relationships are critical to understanding how plant functional group diversity and abundance, which are changing in a greening Antarctica, impact soil communities and processes.

142

An extensive unique open ocean polynya in the central Weddell Sea, Antarctica in December 1980

Dr. Babula Jena¹, Professor John Turner², Ms T. Reeves Francois², Dr. C Holmes², Dr. T. C. Harrison², Dr. T Phillips², Prof. Z Wang³

¹National Centre for Polar and Ocean Research, Goa, India. ²British Antarctic Survey, Cambridge, United Kingdom. ³Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China

Abstract

Polynyas are regions of open water found within sea ice cover that directly influence the ocean and atmospheric circulations, the marine ecosystem, and biogeochemical cycles. Satellite observations show that the Weddell and Maud Rise polynyas first appeared in the 1970s and frequently reoccurred after 2016. We investigate an undocumented extensive open ocean polynya that developed in the central region of the Weddell Sea in December 1980 on the edge of the multi-year sea ice off the east coast of the Antarctic Peninsula. The polynya was first apparent on satellite imagery on 8 December 1980 and expanded until 26 December, with its largest areal extent attained being the same size as France. It is still the largest polynya observed in the central Weddell Sea in the satellite era, contributing significantly to the 1981 Weddell Sea sea ice extent minimum of 0.793 × 106 km2, which was the second lowest on record. We studied the physical mechanism for forming this unique polynya, including the occurrences during the 1970s and post-2016.

143

Pedagogical evaluation of the 3D simulation Antarctica: Witness of Time in the context of scientific education in Brazilian schools

PhD Sandra Freiberger-Affonso, PhD Sílvia Dotta

Universidade Federal do ABC, Santo André, Brazil

Abstract

The 3D digital simulation “Antarctica: witness of time”, is a learning object (LO) that aims to contribute to the teaching of general concepts of climate change through the presentation of the geological history of Antarctica. It was developed supported by Vygotsky's sociointeractionist theory, to be used in the classroom in interdisciplinary contexts, so that students have subsidies that help them in the formation of a scientific culture, as an educational practice. However, after the development of digital educational objects, which involve numerous areas of knowledge, there is a lag in the process of validating and systematizing them: the pedagogical evaluation stage. This step, in general, is neglected in the development processes of this type of LO and requires systematization according to the learning approach that supports its development.

In this research, we adopted the Intera methodology for the development of LO Simulation, the last stage of which is the Pedagogical Assessment, in order to verify whether the LO meets the learning requirements. We carried out the pedagogical evaluation of the 3D simulation to find out if and how it contributes with learning about polar sciences and other school subjects. We applied qualitative research with high school and higher education students and teachers, after using 3D simulation. As a result, we identified the effectiveness of the learning object 3D simulation and the need to describe educational guidelines that contribute to the production of other LO and mainly that contribute to the inclusion of the theme Antarctica and Climate Change in the school curriculum, using technologies to mediate learning.

144

Understanding the Geospace Environment from Antarctica with Autonomous Instrumentation Networks: Interdisciplinary and International Research Advances

Michael Hartinger^1,2, Bob Clauer³, Zhonghua Xu³, Shane Coyle³, Joseph Baker³, Mervyn Freeman⁴, James Weygand², Dogacan Ozturk⁵, Hyomin Kim⁶, Kristina Collins¹, Michelle Salzano¹, Ingrid Cnossen⁴, Terry Wilson⁷, Michael Bentley⁸, Anna Willer⁹

¹Space Science Institute, Boulder, USA. ²UCLA, Los Angeles, USA. ³Virginia Tech, Blacksburg, USA. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵University of Alaska, Fairbanks, USA. ⁶NJIT, Newark, USA. ⁷Ohio State University, Columbus, USA. ⁸Durham University, Durham, United Kingdom. ⁹DTU Space, Lyngby, Denmark

Abstract

Geospace system dynamics can affect our technological infrastructure, for example by inducing damaging electrical currents in the power grid, heating the upper atmosphere and altering satellite orbits, and affecting GPS signals. In principle, the Northern and Southern Hemispheres are electromagnetically connected by Earth’s magnetic field, but this coupling varies in time and space, leading to inter-hemisphere asymmetries in the high-latitude geospace system where impacts are typically greatest. Thus, simultaneous Arctic and Antarctic measurements are crucial for testing our understanding and prediction of geospace dynamics. During recent years, many autonomous measurement systems have been deployed at remote strategic locations in the Antarctic to enable investigations of inter-hemisphere symmetry properties through interdisciplinary collaborations in the USA and internationally. In this presentation, we provide an update on these efforts and the research investigations that they have enabled, highlighting several examples of international and interdisciplinary collaborations: north-south hemisphere asymmetries in ionospheric electrical currents and upper atmosphere heating, data sharing across disciplines to study multi-scale upper atmosphere/ionosphere phenomena during the 2021 Antarctic eclipse, and adapting sonification and mixed reality tools to overcome challenges identifying complex but repeatable geomagnetic disturbance signals. We also discuss challenges in deploying and maintaining autonomous systems as well as future opportunities that address these challenges via inter-disciplinary collaborations.

146

Population ecology of two deep-sea cup coral (likely Family: Caryophilliidae) morphotypes from the Powell Basin, Antarctica

Tasnuva Ming Khan^1,2,3, Huw Griffiths², Andrea Manica¹, Rowan Whittle², Emily Mitchell^1,3

¹University of Cambridge, Cambridge, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³University Museum of Zoology, Cambridge, United Kingdom

Abstract

Drivers of the spatial structure of Antarctic benthic ecosystems are scale-dependent. While large scale factors, such as sea ice cover and extent, and temperature, which operate on tens to hundreds of kilometre scales, are well studied, fine, centimetre scale interactions between organisms and their environment are presently not well understood. We use high resolution seabed photographs taken by the Ocean Floor Observation and Bathymetry System (OFOBS) during the RV Polarstern cruise PS118, to investigate the spatial dynamics of the highly abundant cup corals in the rocky substrates of the Powell Basin. These cup corals, likely of the order Caryophilliidae, have stony corallites and coloured tentacles, usually a pale pink or orangey-red (referred hereafter “pink corals” and “red corals”). We identified 36 photographs with high abundance of cup-corals, which consisted of 3431 pink corals and 1545 red corals across the 36 photographs. The coral morphotypes form both sympatric communities, where both species coexist, and allopatric communities, where either species is (near) absent. We used Spatial Point Process Analysis (SPPA) to infer the processes underlying the cup coral spatial patterns between and within each coral morphotype. We found that patterns of aggregation and segregation, both within and between morphotypes, operate at differing spatial scales between the allopatric and sympatric communities. We hypothesize that the morphotypes respond differently to variations in seabed topography and geomorphology, driving the spatial distribution of these corals.

150

Aurora ripples - a visual ionospheric emissions when auroral plasma sweeping through atmosphere

Dr Bin Li

Polar Research Institute of China, Shanghai, China

Abstract

Based on the multi-scale statistical observations from antarctic Zhongshan station, a rippling aurora-like optical phenomena was observed near the poleward boundary of the aurora. The lack of red emission and extremely small scale indicated the aurora ripple is not likely been the result of the electron or ion perception along the magnetic field line. Through the statistical results of appearance location, fine scale structures and the consistence to the theoretical predication, the Aurora ripple is believed to be mainly caused by the plasma gradient drift instability around aurora. Dreyer et al described this phenomena as Fragmented aurora-like emissions, considering the patterns of emergence and progression associated with this phenomenon, we suggest to name it as "Aurora ripples". This designation is inspired by the visual resemblance of the phenomenon to rippless formed when a paddle moves through a lake, signifying the interaction of auroral plasma with the atmosphere.

151

Southern Ocean Ice Prediction system version 1.0 (SOIPS v1.0): Aiming at support ship navigation in the Antarctic sea ice zone

Dr. Fu Zhao¹, Dr. Xi Liang¹, Dr. Zhongxiang Tian¹, Dr. Ming Li¹, Dr. Na Liu¹, Dr. Chengyan Liu²

¹National Marine Environmental Forecasting Center, Beijing, China. ²Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China

Abstract

An operational synoptic-scale sea ice forecasting system for the Southern Ocean, namely Southern Ocean Ice Prediction System (SOIPS), has been developed to support ship navigation in the Antarctic sea ice zone. Practical application of the SOIPS forecasts had been implemented for the 38th Chinese National Antarctic Research Expedition for the first time. The SOIPS is configured on an Antarctic regional sea-ice‒ocean‒ice-shelf coupled model and an ensemble-based Localized Error Subspace Transform Kalman Filter data assimilation model. Daily near-real-time satellite sea ice concentration observations are assimilated into the SOIPS to update sea ice concentration and thickness in the 12 ensemble members of model state. By evaluating the SOIPS performance on forecasting sea ice metrics in a complete melt-freeze cycle from October 1, 2021 to September 30, 2022, this study shows that the SOIPS can provide reliable Antarctic sea ice forecasts. In comparison with the OSISAF data, annual mean root mean square errors of the sea ice concentration forecasts at leading time of up to 168-hour are lower than 0.19, and the integrated ice-edge errors of sea ice forecasts in most freezing months at leading times of 24-hour and 72-hour maintain around 0.5 × 10⁶ km² and below 1.0 × 10⁶ km², respectively. With respect to the scarce ICESat-2 observations, the mean absolute errors of the sea ice thickness forecasts at leading time of 24-hour are lower than 0.3 m, which is in range of the ICESat-2 uncertainties. Specifically, the SOIPS has a promised capacity in forecasting sea ice drift, both in magnitude and direction. The derived sea ice convergence rate forecasts have a high potential in supporting ship navigation on local fine scale.

152

Protecting Antarctica: creating a balance between preservation and tourism

Ms Lea Kannar-Lichtenberger

JLL BelleBear Foundation, Sydney, Australia

Abstract

Protecting Antarctica will use Lea Kannar-Lichtenberger's contemporary art practice to examine the impact of the tourist, both as an individual and in groups. As an artist/traveller/observer, Kannar-Lichtenberger utilizes her past (2017) and more recent (2023) self-funded Antarctic research expeditions to consider the visitor's engagement with the fragility of Antarctica. Her observations and responses utilize the artist's lens to develop a visual discourse. She explores humanity's impact whilst raising questions about the dilemma surrounding preservation versus the tourism juggernaut.

This paper will consider how artworks and conceptual art can engage with the community about science and initiate broader discussions. Kannar-Lichtenberger will use her visual and written creative works to shed light on how tourists and tour companies explore and exploit this fragile environment. Through artworks such as her thermal imaging video installation, Footprints – Convergence Penguin Highway 2023, Kannar-Lichtenbergers opens a window into the relationship between history, the tourist, and the local wildlife. Her research and artworks raise questions, relating but not limited to, how pre-emptive adversarial thinking is engaged with the current biosecurity of the area concerning 'Bird flu' and 'Invasive species', as it tries to work in tandem with the tourist's expectations.

Kannar-Lichtenberger's research considers the underlying aspects of tourism, revealing how much these practices can be seen to reinforce the global impact of climate change and the Anthropocene.

154

Organic matter remineralization and nutrient regeneration in the Indian sector of southern ocean: implications on nutrient dynamics and ocean biological pump

Dr. Melena A. Soares, Dr. R.K. Mishra, Dr. V. Venkataramana, Dr. P. Sudarsanarao, Dr. P. Sabu, Dr. N. Anilkumar, Dr. Rahul Mohan

National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco da Gama, Goa, India

Abstract

Southern ocean is very important in the global ocean biogeochemistry and as a net source of nutrients supply via circulation and watermass interactions, that link the global oceans. Small climatic variations in the Southern ocean can produce pronounced biogeochemical responses in this oceanic regime. The current study was carried out to understand the various factors contributing to organic matter remineralization across the fronts of the Indian sector of the southern ocean, its impact on nutrient dynamics and associated biogeochemical processes of the ocean biological pump. To address this, seawater samples were collected from across the fronts of the Indian sector of the Southern Ocean and analyzed for various physico-chemical and biological variables. The results from the chemical variables and statistical analysis implied a significant spatial variability in the extent of remineralization, contributing to the nutrient dynamics especially via regenerated nutrients. The recycling of nutrients due to organic matter remineralization was considerably higher in the subtropical waters, however, varied temporally. Additionally, the findings ascertain the role of water masses on the nutrient dynamics and biological community structure, impacting the efficiency of the biological pump via organic matter export and/or remineralization. It was evident that the factors controlling the organic matter transformation, remineralisation and nutrient dynamics in the photic waters and below the photic depth varied considerably. Besides, front specific factors like eddies, water mass intrusion and sea-ice cover or melting significantly contributed to the changing nutrient variability and dependent biogeochemical processes, impacting the biological pump. Thus, changes in the ocean temperature, ice-melt, stratification, etc., as a response to changing climate, can trigger a chain of events influencing the biogeochemical processes and the efficiency of the biological pump in the Southern ocean.

155

What drives zooplankton assemblages in the coastal waters of Eastern Antarctica during sea ice melting season?

Dr Vankara Venkataramana¹, Dr R.K. Mishra¹, Dr Melena A. Soares¹, Dr P. Sabu¹, Dr A. Sarkar², Dr Rahul Mohan¹

¹National Centre for Polar and Ocean Research; Ministry of Earth Sciences, Vasco-da-Gama, India. ²Kuwait Institute for Scientific Research, Safat, Kuwait

Abstract

The East Antarctic coastal region is extremely significant and well-known as a critical reference point for tracking the effects of climate change on ocean dynamics. It is previously believed that the east Antarctic ice sheet was more stable than the west Antarctic Peninsula, but there has recently been concern that east Antarctica may be more susceptible to temperature rise. Zooplankton studies in the coastal waters of eastern Antarctica (Indian Ocean sector) have received less scientific attention than the western Antarctica. To address the shortfall of information, we investigated the role of hydrodynamics on vertical structure of zooplankton until 1000m, by using a standard multiplankton sampler (mouth area: 0.25m²; mesh size: 200 µm). Relatively, the neritic zone had a shallower mixed layer than the Ice-free domain. The recorded temperature in the neritic zone was quite unusual and had never been recorded previously. This abnormal temperature did not impact the zooplankton biovolume and numerical abundance much in the neritic zone. Freshening of the surface water prevented both phytoplankton and zooplankton biomass in the seasonal ice zone, resulting in high zooplankton biovolume and diversity in the subsurface layer. The high zooplankton biovolume in the neritic zone and ice-free zone was likely caused by no sea ice melting and high phytoplankton biomass (Chl-a). Calanoids and cyclopoids composed the majority of the overall zooplankton biovolume, accounting for more than 81% of the total zooplankton count. Calanus simillimus and Calanus australis are important in the oceanic region, where Stephos longipes is an indicator species in the shelf region. We hypothesised that the sea surface warming, declining sea ice, reduced salinity, food availability and water masses alter the structure and function of zooplankton composition in the study area. Consequently, these changes are likely to have a significant impact on the biogeochemical process in coastal Antarctica.

156

Impacts of the Long-term Atmospheric Trend on the Seasonality of Antarctic Sea Ice

Dr. Fu Zhao¹, Dr. Xi Liang¹, Dr. Zhongxiang Tian¹, Dr. Chengyan Liu², Dr. Xichen Li³, Dr. Yun Yang⁴, Dr. Ming Li¹, Dr. Na Liu¹

¹National Marine Environmental Forecasting Center, Beijing, China. ²Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China. ³Institute of Atmospheric Physics, Beijing, China. ⁴Beijing Normal University, Beijing, China

Abstract

The sea ice cover has experienced substantial changes in Antarctica in the past decades, yet its responses to the long-term trend of the local atmosphere are still not clear. With the aid of an Antarctic coupled sea ice-ocean-ice shelf model, the sea ice seasonality in response to the long-term trend of the local atmospheric forcing has been quantified based on a sea ice budget analysis. Significantly spatial variabilities have been found in the Antarctic sea ice in response to the long-term trend of the local atmospheric forcing. The sea ice area and volume decrease in the Weddell Sea and increase in the Ross Sea throughout the year. In the Amundsen-Bellingshausen Seas sector, the sea ice area decreases from December to June and increases from July to November, while the sea ice volume decreases throughout the year. In the Indian-Western Pacific Oceans sector, the sea ice area decreases from January to May and increases from June to December, while the sea ice volume increases throughout the year. The long-term trend of the local atmospheric forcing modulates the sea ice loss in the melting period mainly through modifying the ice-ocean heat flux over the ice base, while it governs the sea ice growth in the freezing period by the combined effects of the ice-ocean heat flux and the atmosphere-ocean heat flux. Although the trend of the surface wind can also lead to distinct variations by the local sea ice convergence/divergence, the integrated contributions over the basin scale are relatively small.

157

Three-year atmospheric seeing monitoring at Dome A, Antarctica

Prof Zhaohui Shang¹, Prof Bin Ma², Prof Yi Hu¹, Prof Michael Ashley³, Dr Xu Yang¹

¹National Astronomical Observatories, CAS, Beijing, China. ²Sun Yat-sen University, Zhuhai, China. ³University of New South Wales, Sydney, Australia

Abstract

The nighttime seeing at Dome A was initially measured by KL-DIMM in 2019, revealing free-atmosphere seeing with a median value of 0.31 arcseconds for 31% of the time at a height of 8 meters. KL-DIMM was serviced in 2023 and 2024, with data collection currently ongoing for the third year. The distribution of the seeing measurements appears to be consistent and we will present the statistics of both night-time and daytime seeing data from the three years. In addition, based on the finding of a strong correlation in the 2019 daytime data between the seeing values and the meteorological parameters from KLAWS, we investigate if this correlation also exists during nighttime and try to better understand the turbulence at Dome A. Possible annual variations of seeing and their implications for astronomical observations will be discussed.

162

Assessing distribution and sources of regulated versus emerging contaminants in Admiralty Bay, Antarctic Peninsula.

MSc Letícia Costa¹, MSc María de la Luz Salvador², PhD Marina Pintado-Herrera², PhD César Martins³, PhD Rafael Lourenço³, PhD Tatiane Combi¹

¹Universidade Federal do Paraná, Pontal do Paraná, Brazil. ²Uniservidad de Cádiz, Cádiz, Spain. ³Universidade de São Paulo, São Paulo, Brazil

Abstract

Despite being the most remote area on the planet, the Antarctic continent faces increasing anthropogenic pressures, as evidenced by the detection of different groups of regulated contaminants in the region, including persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs). More recently, emerging contaminants (ECs) have been investigated and detected in Antarctica, indicating that new types of contaminants are being introduced in this pristine environment. This study provides an updated analysis of POPs, PAHs, and ECs in surface sediments from Admiralty Bay, Antarctica Peninsula. Samples (n=17) were extracted using an accelerated solvent extraction system and analyzed using gas chromatography coupled to a triple-quadrupole mass spectrometer. Regulated pollutants were higher in the Martel inlet, suggesting local human activities (e.g., logistical activities, wastewater discharge) as potential sources. Σ₁₆PAHs were found in concentrations ranging from 2.6 to 617.4 ng g^-1, while Σ₅PCBs were at significantly lower levels (≤0.5 ng g^-1). Notably, ECs, including UV filters homosalate (0.3 to 251.3 ng g^-1) and octocrylene (0.7 to 93.8 ng g^-1), were detected near research stations in Ezcurra and Martel inlets. The organophosphate flame-retardant tri (2-chloro-1-methylethyl) phosphate (0.1 to 87.4 ng g-1) and the fragrance galaxolide (0.2 to 55.0 ng g-1) were also detected in these two inlets. These findings suggest that the levels of ECs are likely associated with the larger human occupation and continuous operation of research stations, in contrast to the Mackelar inlet, where considerably lower contaminant concentrations were observed. This study contributes with updated data on traditional pollutants, which show a decreasing trend in comparison to previous data. Additionally, the presence of ECs was reported for the first time in Admiralty Bay, highlighting the need for ongoing monitoring and further investigation into the environmental behavior and impacts of these contaminants in remote areas.

163

Southern Ocean deep-sea food-webs: a look into the structure, the benthopelagic coupling and the influence of environmental conditions

José P. Queirós^1,2, Dr Philip R. Hollyman^2,3, Dr Mark Belchier², Dr José C. Xavier^1,2

¹University of Coimbra, Marine and Environmental Sciences Centre (MARE)/ Aquatic Research Network (ARNET), Coimbra, Portugal. ²British Antarctic Survey (BAS), Natural Environmental Research Council (NERC), Cambridge, United Kingdom. ³School of Ocean Sciences, University of Bangor, Bangor, United Kingdom

Abstract

Food-webs are determinant for the functioning and structure of marine ecosystems. The Southern Ocean food-web is traditionally presented as short and dominated by an Antarctic krill surplus. Recent studies proved the existence of alternative pathways, with other krill, fish, and cephalopod species linking primary producers to top-predators. However, these studies mostly focused in the pelagic and coastal environments. Here, we present the results of the geographical variation of the poorly known deep-sea food-web structure on the Scotia Sea (from South Georgia (SG) to South Sandwich Islands (SSI)), and food-web interannual variability at SSI, using stable isotopes and fatty acids techniques. Results show that deep-sea food-webs have five trophic-levels, with both Antarctic (Dissostichus mawsoni) and Patagonian (D. eleginoides) toothfish as the top predators in the SSI, but with the Bigeye grenadier (Macrourus holotrachys) occupying the highest trophic position at SG. All these food-webs have a fourth trophic level mainly composed by fish and a third trophic level by cephalopods and crustaceans. Our results suggest that deep-sea food-webs including both pelagic and benthic/demersal organisms are longer than coastal and pelagic food-webs in the Southern Ocean. At SSI the benthopelagic coupling happens mainly from the third (pelagic) to the fourth trophic level (benthic/demersal), though at SG a mix of both pelagic and benthic species in both trophic levels were found, suggesting a continuous exchange between the pelagic and benthic/demersal components of the food-web. Changes in the food chain length across three consecutive years at SSI related with the net primary productivity, with the longest food-web being found in the year with highest productivity. Longer food-webs are less stable and recover slower from perturbations. Therefore, increasing productivity with climate change may increase the vulnerability of deep-sea benthopelagic communities in the Southern Ocean.

165

Unveiling Unattended Narratives: Chilean Artists' Representation of Antarctica Beyond Colonial Narratives

Dr Alejandra Pérez

Universidad de Valparaíso, Valparaíso, Chile

Abstract

In recent years, there has been a growing interest among artists worldwide in exploring different representations of Antarctica. The majority of the discourse surrounding Antarctic art has been dominated by colonial narratives of grandeur and heroism, overshadowing the diverse and nuanced perspectives that artists from different cultural backgrounds bring to the table. In this presentation, we aim to shed light on the works of Chilean artists who have actively sought to challenge these predominant narratives and represent unattended subjects of the Antarctic region.

Drawing on the works of Chilean artists such as Fernando Prats, Francisca García, Allan Jeffs, and Alejandra Perez, this presentation will showcase a diverse range of artistic interpretations of Antarctica. These artists, through their unique perspectives and artistic mediums, have delved into themes such as environmental conservation, more-than-human perspectives, and the human impact on the Antarctic landscape. By doing so, they offer a fresh and alternative view of Antarctica that transcends the traditional notions of the sublime.

Furthermore, this presentation will contextualize the works of Chilean artists within the broader landscape of international Antarctic art. By examining the contributions of artists from around the world who are similarly challenging conventional narratives, we aim to highlight the richness and complexity of artistic representation in the Antarctic context. Through an exploration of these diverse artistic voices, we hope to inspire dialogue and critical reflection on the multiple dimensions of Antarctica as a subject of artistic inquiry.

166

Increasing synchronization of Antarctic and global climate since the Mid Pleistocene Transition

Michael E. Weber¹, Ribana Roscher², Axel Timmermann³, Peter U. Clark⁴, Kyung-Sook Yun³, Nicholas R. Golledge⁵, Yasmina M. Martos⁶, Mehmet E. Karaesmen⁷, Yi Zhong⁸

¹Institute for Geosciences, Department of Geochemistry and Petrology, University of Bonn, Bonn, Germany. ²Institute of Geodesy and Geoinformation, University of Bonn, Bonn, Germany. ³Center for Climate Physics, Institute for Basic Science, Busan, Korea, Republic of. ⁴College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, USA. ⁵Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ⁶NASA Goddard Space Flight Center, Greenbelt, USA. ⁷Institute for Geosciences, University of Bonn, Bonn, Germany. ⁸Southern University of Science and Technology, Shenzhen, China

Abstract

As an integral part of Earth’s climate system the Antarctic Ice Sheet (AIS) impacts global sea level, and interacts with large-scale climate and the carbon cycle on a variety of timescales. So far, due to a lack of long and continuous records of AIS variability on orbital timescales (19-405 thousand years), it has remained difficult to unravel the complex interplay between the AIS, ocean, atmosphere, and biogeochemical cycles and their response to Milanković cycles. Using high-resolution sediment core data from Iceberg Alley in the Southern Ocean, in combination with climate and ice-sheet model simulations, we show that around 1.5 million years ago (Ma), Southern Ocean productivity, dust, sea-ice and sea-surface temperature started to synchronize with orbitally-paced global climate change. Subsequently, by around 0.9 Ma, inferred variations in AIS volume from iceberg-rafted debris variability, began to vary in unison with indicators of global climate, and by 0.4 Ma the entire ice-ocean-atmosphere system was locked into an orbital rhythm. The lack of strong Milanković signals prior to 0.9 Ma indicates sensitivity thresholds for the Southern Ocean carbon cycle and the AIS, with the increasing amplitude of CO₂ variations after the Mid-Pleistocene Transition likely being the major driver for the synchronization.

167

Multiple tipping points destabilizing the Antarctic Ice Sheet during the last and the penultimate glacial termination

Michael E. Weber¹, Nicholas R. Golledge², Chris J. Fogwill³, Chris S.M. Turney^4,5, Zoë A. Thomas^4,5, Natalya Gomez⁶, Laurie Menviel⁷

¹Institute for Geosciences, Department of Geochemistry and Petrology, University of Bonn, Bonn, Germany. ²Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ³School of Water, Energy and Power, Cranfield University, Cranfield, United Kingdom. ⁴Earth and Sustainability Science Research Centre, School of Biological Earth and Environmental Sciences, University of New South Wales, Sydney, Australia. ⁵ARC Centre of Excellence in Australian Biodiversity and Heritage, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia. ⁶Department of Earth and Planetary Sciences, McGill University, Montreal, Canada. ⁷Climate Change Research Centre, University of New South Wales, Sydney, Australia

Abstract

Emerging ice-sheet modeling suggests once initiated, retreat of the Antarctic Ice Sheet (AIS) can continue for centuries. Unfortunately, the short observational record cannot resolve the tipping points, rate of change, and timescale of responses. Iceberg-rafted debris data from a deep ocean core in Iceberg Alley – the central gateway for Antarctic iceberg routing in the Soctia Sea – identifies eight retreat phases of the AIS after the Last Glacial Maximum between ~19 ka and ~9 ka. Each of these Antarctic Ice-Sheet Discharge (AID) events destabilized the AIS within a decade and then contributed to global sea-level rise for centuries to a millennium. Re-stabilization then occurred equally rapidly within a decade or two. This dynamic response across multiple tipping points of the AIS is supported by empirical evidence from a West Antarctic blue ice record of ice-elevation drawdown >600 m during three such AID events related to globally recognized deglacial meltwater pulses, and by a step-wise retreat up to 400 km across the Ross Sea shelf. Independent ice-sheet modeling confirms that calving and grounding line retreat co-vary on decadal scales today and that the total modelled deglacial AIS mass loss mimics the IBRD flux rate in Iceberg Alley, with the most discernable tipping points for AIS re-stabilization. Ongoing work on new sites from Iceberg Alley, obtained during International Ocean Drilling Project Expedition 382, also indicates multiple AIS tipping points across the penultimate glacial termination following Marine Isotopic Stage 6. Combined, these findings are consistent with a growing body of evidence suggesting the recent acceleration of AIS mass loss may mark the begin of another prolonged period of ice sheet retreat and substantial global sea-level rise.

169

From a Frozen Continent to a Hot Diplomatic Agenda. The Changing Status of Antarctica in Global Governance Talks.

Dr Ana Flávia Barros-Platiau^1,2,3, Dr Jorge Barros⁴, Dr Fábio Henrique Granja e Barros⁵

¹University of Brasília, Brasília, Brazil. ²Superior Defence College, Brasília, Brazil. ³Earth System Governance network, Utrecht, Netherlands. ⁴Retired from the University of Brasilia, Brasília, Brazil. ⁵Federal Accounting Court, Brasília, Brazil

Abstract

Antarctica has been explored and described as a very far and dangerous place (land and sea) since more than 200 years ago. It is also considered a continent upon which sovereignty claims have been frozen, while a governance framework was set by the 1959 Treaty. Since then, it has been established that human activities and voting rights at the ATCM depend directly on the development of scientific research and the diplomatic priorities of member states. Therefore, the Antarctic regime has been developed as if Antarctica could be separated from the rest of the Planet and the United Nations governance. Consequently, CRAMRA, CCAMLR and the Madrid Protocol were shaped after long negotiation meetings. Therefore, this paper focuses on tracing the process of the changing status of Antarctica: from a frozen continent to the centre of the diplomatic agenda due to the role of the scientific community and their reports. The "white world" (Shankar et al, 2019) is now The main claims are: i) Antarctica cannot be detached from the climate change issue, as the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate stated (DeConto et al, 2021); ii) There is a recent US-China/Russia geopolitical shift that brings new light to Antarctica research priorities, and iii). The status of Antarctica changed in four dimensions: scientific, economic, geopolitical and diplomatic. In this context, what are the implications of the rapidly changing global governance on the status of Antarctica? We contend that Antarctica is a diplomatic priority only for some members, but it needs to be a priority for all. Also that the Antarctica agenda needs to be inextricably connected to other minilateral and multilateral regimes, concerning climate change and the ocean. As a result, the ATS regime needs to be updated to respond to this new diplomatic status.

170

Assessing efficacy in MPA design decisions using a bespoke and interactive fisheries management tool

Dr Oliver Hogg

Cefas, Lowestoft, United Kingdom

Abstract

Large marine protected areas (LMPAs) represent one of the main strategic options for achieving international targets on mitigating biodiversity loss and ensuring habitat protection. Many LMPAs incorporate some multi-use elements within their design, such as provisions for managed fisheries. This adds complexity to MPA design, requiring prioritisation of spatial closures to ensure design efficacy. Using a subantarctic island case study, here we present a novel, bespoke and interactive ‘risk tool’. The tool utilises historic fisheries data and longline fisheries-mounted camera systems to quantify the ecosystem impacts of current longline fishing and simulates the change in risk profile of fishing displacement resulting from potential MPA redesigns on associated species and ecosystems.

172

Soil microbial communities in Larsemann Hills, East Antarctica: environmental controls and human-induced effects

Ivan Alekseev¹, Elena Grek^1,2

¹Arctic and Antarctic Research Institute, Saint Petersburg, Russian Federation. ²State Hydrological Institute, Saint Petersburg, Russian Federation

Abstract

Ice-free areas cover only about 0.1% of Antarctica and are characterized by harsh environmental conditions. However, these regions provide diverse conditions for soil-forming process having various physical and geochemical properties resulting different conditions for living organisms. Relatively little attention has been shown towards soil microbial communities, although they could serve to enhance our knowledge on life adaptation strategies under such harsh environmental conditions. Our study is aimed at determining existing soil microbial communities, their interrelations with soil parameters as well as the influence of human activities in Larsemann Hills, East Antarctica. The soil microbiome was investigated at different locations using 16 S rRNA gene pyrosequencing. The taxonomic analysis of the soil microbiomes revealed 12 predominant bacterial and archeal phyla - Proteobacteria, Actinobacteria, Acidobacteria, Chroloflexi, Gemmatimonadetes, Verrucoms. microbia, Planctomycetes, Bacteroidetes, Armatimonadetes, Firmicutes, Cyanobacteria, Thaumarchaeota. Some specific phyla have been also found in sub-surface horizons of soils investigated, providing additional evidence of crucial role of gravel pavement in saving the favorable conditions for both soil and microbiome development. Moreover, our study also revealed that some bacterial species might be introduced into Antarctic soils by human activities. We also assessed the effect of different soil parameters on microbial community in harsh environmental conditions of Eastern Antarctica. pH, carbon and nitrogen, as well as fine earth content were revealed to be the most predictors of soil bacterial community composition. The results of this study could be used could be potentially useful for the purposes of environmental risk assessment and effective conservation of fragile Antarctic ecosystems. This study has been supported by the grant of the Russian Scientific Foundation, project № 24-27-00361.

179

Ice Floe Characterisation using a Ship-based Camera Technique

Dr Sebastien Delaux¹, Dr Peter McComb¹, Ms Sally Garrett²

¹Oceanum Ltd, New Plymouth, New Zealand. ²Defence Science and Technology, New Zealand Defence Force, Auckland, New Zealand

Abstract

A ship-based optical sensing technique to detect and measure individual ice floe objects has been developed as part of radar performance trials conducted by Defence Science and Technology, New Zealand Defence Force. The trials were undertaken during a resupply voyage by HMNZS Aotearoa to McMurdo Base Antarctica during February 2022.

A standard SnapIT fishing vessel monitoring camera was fitted to the upper bridge deck of the ship, with the bow and starboard side in the field of view. Images were recorded at 15hz and 1920x1080 pixel size. Discretisation of the individual ice floes in the footage was made from georeferenced polygons. The video was first subsampled to 1Hz and orthorectified using location and measured ship motions. In each subsequent image, floe locations were estimated by first identifying ice pixels using a threshold and then grouping them into coherent structures following an approach similar to Zhang and Skjetne (2014). The final ice floe polygons were extracted using a machine learning-based segmentation approach.

The method shows a detection limit of around 2m, with best efficacy up to about 3/10th ice. At higher ice densities the segmentation routines were less effective. The technique allows a measurement swath of 250m to be made, and the post processing defines all objects with size (area, length and width). Floe size distributions and densities (in tenths) as well as drift speed and direction can be readily derived.

While the method was developed for the New Zealand Defence Force radar trials, it offers a simple but effective way for any ship of opportunity to make useful and highly quantitative observations of sea ice. This concept was tested during the 2024 season on the RV Laura Bassi, and further voyage opportunities will be used in the 2025 season. The code base developed in this work is openly available.

188

The CLIVAR/CliC/SCAR Southern Ocean Region Panel: present and future actions

MSc Alvaro Scardilli^1,2, Dr Channing Prend³

¹CLIVAR/CliC/SCAR Southern Ocean Regional Panel, Buenos Aires, Argentina. ²Servicio de Hidrografía Naval, Buenos Aires, Argentina. ³University of Washington, Seattle, USA

Abstract

The Southern Ocean Region Panel (SORP) works as an Expert Group within CLIVAR and aims to coordinate the discussion and communication of scientific advances in climate variability and change in the Southern Ocean and its ice-ocean interactions with Antarctica. As part of this mission, SORP also has a protagonist role in the development of research or education projects and dissemination of knowledge.

SORP is co-sponsored by the World Climate Research Programme’s Climate and Ocean: Variability, Predictability and Change (CLIVAR) and the Climate and Cryosphere (CliC) projects, and SCAR, advising those bodies on progress, achievements, new opportunities and impediments in internationally coordinated Southern Ocean research.

SORP activities are focused on facilitating progress in assessing climate variability and predictability of the ocean-atmosphere-ice system of the Southern Ocean, provide scientific and technical input into international research coordination, monitor and evaluate progress in Southern Ocean research, enhance interaction between the meteorology, oceanography, cryosphere, geology, biogeochemistry and paleoclimate communities with an interest in the climate of the Southern Ocean, and work with relevant agencies on the standardization, distribution and archiving of Southern Ocean observations.

SORP achieves these goals in 2023 and 2024 by conducting or participating in the following projects:

SOFIA: CLIVAR Southern Ocean Freshwater release model experiments Initiative task team.

PROS4SORP Seminars: quarterly virtual seminar series ‘Presenting Recent Ocean Science for the Southern Ocean Regional Panel’.

CLIVAR Exchange Special Issue: entitled "Highlighting Ocean Research, Data and Networks of Antarctic Programs", will showcase SO research being undertaken by emerging Antarctic programs and/or researchers originally from countries without a well-established Antarctic program.

ICTP-SORP-NORP Summer School and Workshop on Polar Climates: this activity will emphasize the interactions between the cryosphere, ocean and atmosphere within polar regions. Both Arctic and Antarctic regions will be discussed by leading experts who will highlight similarities and differences between these regions.

192

Sleep in Antarctica: a tale of two cities and four seasons.

Prof Nathalie Pattyn^1,2, Prof Martine Van Puyvelde¹, Dr Jeroen Van Cutsem¹, Prof Olivier Mairesse³, Mrs Amélie Rolinat^2,1, Dr Nicholas van den Berg^1,2, Prof Guido Simonelli^2,4, Dr Céline Dupin⁵, Dr Evangelos Kaimakamis⁵, Dr Greig Lawson⁶, Prof Igor Mekjavic⁷, Dr Jérémy Rabineau⁸

¹Royal Military Academy, Bruxelles, Belgium. ²Université de Montréal, Montréal, Canada. ³Vrije Universiteit Brussel, Bruxelles, Belgium. ⁴CIUSSS NIM, Montreal, Canada. ⁵TAAF, Paris, France. ⁶British Antarctic Survey, Cambridge, United Kingdom. ⁷Jozef Stefan Institute, Ljubljana, Slovenia. ⁸Université Libre de Bruxelles, Bruxelles, Belgium

Abstract

According to the literature, sleep disturbances are worse in the Antarctic winter, the period of isolation and constant darkness (latitude dependent). This is confirmed by results on much larger samples from Arctic regions. However, there is still no consensus on the causal mechanisms, and there is a lack of investigations during the period of constant illumination.

The current project investigated sleep (through polysomnography and sleep diaries) and its circadian regulation (through saliva sampling of cortisol and melatonin) during summer, winter, and either spring or autumn in two different stations (Halley VI and Dumont d’Urville), for two full seasons in each station. To disentangle the effect of time on station, cultural context and the effect of seasonality, summer measurements were divided in “first summer” measures and “second summer” measures.

The results show the same sleep disturbances for both summer and winter when it was measured after more than 6 months on site. When summer measurements were recorded after 1 month on site, the results paint a slightly different picture: sleep onset latency is similarly disturbed, but the amount of slow wave sleep and sleep efficiency are less affected; crew members spend less time in bed and report less subjective sleepiness and fatigue. A melatonin phase delay was present at all seasons in all groups. Several interesting differences show up between stations, underscoring the importance of the cultural context. These results underscore that there is more to sleep in Antarctica than a disturbed photoperiodicity: the duration of time-on-station has a major effect on the psychophysiological adaptation. Overall, the present results show the need for a specific support to personnel from both summer and winter campaigns in terms of sleep and fatigue management.

193

Pre- and post-LGM grounding line oscillations reconstructed from the Ross Bank Paleo-Ice Rise in Ross Sea, Antarctica

Dr. Philip Bart¹, Matthew Danielson¹, Ben Lindsey¹, Dr. Lindsay Prothro², Dr. Amy Leventer³, Dr. Ryan Venturelli⁴, Dr. Wojciech Majewski⁵

¹Louisiana State University, Baton Rouge, USA. ²Texas A&M University-Corpus Christi, Corpus Christi, USA. ³Colgate University, Hamilton, USA. ⁴Colorado School of Mines, Golden, USA. ⁵Institute of Paleobiology PAS, Warsaw, Poland

Abstract

The West Antarctic Ice Sheet (WAIS) experienced significant oscillations in thickness and extent during Pleistocene climates cycles. During the post-LGM, for example, the Ross Sea grounding line retreated more than 1000 kilometers from the continental shelf edge before re-advancing over 200 km to its current location (e.g., Venturelli et al., 2023). Here we reconstruct WAIS advance and retreat at Ross Bank, a broad shallow area in central Ross Sea, that was formerly an important ice rise for the Ross Ice Shelf (RIS). During NBP2302/03, we acquired several cores from the crest of Ross Bank. The cores show that an extensive sand-rich residual glacial marine sediment on the bank crest is highly fossiliferous. We radiocarbon dated marine macrofossils, including coral and barnacle plates. A cluster of older radiocarbon ages (n=14) indicates that the bank was free of grounded ice until at least 38,000 ± 870 years BP (uncorrected). These older dates from Ross Bank are generally agree with a relatively late advance of the WAIS during the LGM (Emslie et al. 2007). The younger cluster of radiocarbon ages (n=16) indicates that grounded ice had begun to retreat from the bank by 7990 ± 30 years BP (uncorrected). The younger dates are consistent with prior retreat of grounded ice from the adjacent basins (e.g., Prothro et al., 2020). These findings show that 1) shallow banks provide useful information for paleoclimate reconstructions and 2) that Ross Bank was a long-lived, ice-rise pinning points that partly controlled WAIS extent during the pre- and post-LGM.

201

The Ross Ice Shelf cavity in the new coupled model Polar-SKRIPSv2

Dr Alena Malyarenko^1,2, Dr Alexandra Gossart², Mr Nikhil Hale², A Prof Yoshihiro Nakayama³

¹University of Canterbury | Te Whare Wānanga o Waitaha, Ōtautahi | Christchurch, New Zealand. ²Te Puna Pātiotio | Antarctic Research Centre, Te Herenga-Waka Victoria University of Wellington, Wellington, New Zealand. ³Institute of Low-Temperature Science, Hokkaido University, Sapporo, Japan

Abstract

We have developed the first fully coupled regional model Polar-SKRIPSv2 for the Ross Sea. We use the Polar-SKRIPSv2 as published in Gossart et al. (In Prep). This coupled model uses the MITgcm model of the ocean, and the Polar version of the Weather and the Weather Research and Forecasting Model (PWRF). Our model is unique in conserving energy and can operate at the regional scale, making it the best tool to study mesoscale processes in the Ross Sea and make predictions on how variability of local wind jets above the continental shelf can impact the salinity and temperature of the ocean, and thus global thermohaline circulation.

In this presentation, we will show a case study for the present day (forced by reanalysis) and future simulations (forced by ACCESS-ESM1.5). We focus on the sea ice production, heat and mass fluxes in the polynyas, and show how those change in the future simulations. We also show the changes in the cavity conditions.

202

Does the vehicle shape the ride: An investigation of the population structure of grenadier fish (Macrourus whitsoni )and parasitic copepod

Mr Vahid Sepahvand¹, Dr Clare Adams², Dr Grant Duffy¹, Dr Ludovic Dutoit³, Professor Miles Lamare¹, Professor Ceridwen Fraser¹

¹Marine Science Department, University of Otago, Dunedin, New Zealand. ²Ministry for Primary Industries, Wellington, New Zealand. ³Department of Zoology, University of Otago, Dunedin, New Zealand

Abstract

The population genetic structure of marine species is influenced by a range of factors, including geological history and physical oceanography. However, there is limited understanding of the driving forces of parasite population structure. The general consensus is that parasite genetic structure usually resembles that of the host, as host dispersal is thought to facilitate parasite dispersal. To investigate if a host–parasite pair (the fish Macrourus whitsoni and its parasitic copepod Lophoura sp.) exhibits comparable population genetic structure across the Ross Sea, we characterised the population structure of both species using single nucleotide polymorphism data generated by Genotyping-by-Sequencing at broad (> 100s of km) and regional scale (100s of kms) resolution. We hypothesised that host and parasite would show drastically different genetic structures as they differ in their capacity to disperse during their independent pelagic larval stages. We expected environmental factors including local and large-scale currents and glacial-interglacial cycles to have an impact on the distribution of genetic diversity in hosts and parasites. Our preliminary analysis on the fish host M. whitsoni showed fairly homogeneous population structure, however we require additional samples of the fish as well as samples of parasite copepod to conduct comprehensive analyses. Our findings nonetheless provide exciting insights into connectivity of marine species in the Ross Sea, demonstrating the power of genomic approaches that can assist with monitoring and assessing the effectiveness of the Ross Sea region Marine Protected Area

208

The Troll Observing Network (TONe): A contribution to improving observations in the data-sparse region of Dronning Maud Land, Antarctica

Dr. Christina A. Pedersen¹, Birgit Njåstad¹, Dr. Wenche Aas², Prof. Elin Darelius³, Dr. Sebastien Descamps¹, Stig Flått¹, Dr. Tore Hattermann¹, Dr. Stephen R. Hudson¹, Prof. Wojciech J. Miloch⁴, Simen Rykkje¹, Dr. Johannes Schweitzer⁵, Dr. Rune Storvold⁶, Stein Tronstad¹

¹Norwegian Polar Institute, Tromsø, Norway. ²NILU, Kjeller, Norway. ³University of Bergen, Bergen, Norway. ⁴University of Oslo, Oslo, Norway. ⁵NORSAR, Kjeller, Norway. ⁶NORCE Norwegian Research Center AS, Tromsø, Norway

Abstract

Long-term observations from Antarctica are limited both in space and time and vast areas of the continent currently lack any form of sustained observation systems. The existing observations are mainly taking place around the permanent research stations, which are focused on the peninsula and at the coast. The Norwegian Troll research station is located in Dronning Maud Land, in a data sparse region, 200 km from the coast on the slope to the Antarctic plateau. In this region, at and around Troll research station, a consortium of Norwegian and international partners is currently establishing a sustained state-of-the-art, multi-platform, multi-disciplinary observing network – the Troll Observing Network (TONe).

TONe encompasses eight dedicated observatories, a remotely piloted aircraft system (RPAS) and a well-structured data management system. The observatories will collect and make available data on climate, atmospheric and oceanic processes, ice sheet dynamics and its influence on sea level rise, and the marine ecosystems. The RPAS service will in a cost-efficient manner enable the collection of a wide variety of data over the region with a limited environmental footprint. The data system will allow for a broad and free access to all data to the wider international science community.

We would like to see the TONe initiative as part of a joint effort for improving access to sustained societally relevant long-term observations from Antarctica. By sharing information about the observing system and the shared service, we would like to invite the wider research community to work with us and utilize the data and service to advance our understanding of the climate and environmental change we are facing today.

210

Citizen Science as a Catalyst for Sustainable Antarctic Tourism: Insights from Antarctica21's Onboard Program

Catalina Ovando Arias

Antarctica21, Punta Arenas, Chile

Abstract

Antarctica stands as a crucial frontier for scientific inquiry , offering unique insights into the Earth's ecosystems and climate systems. As human activity increadingly impacts this pristine environment, understanding and mitigating these effects become paramount. However, conducting research in Antarctica is inherently challenging and costly, necessitating innovative approaches to gather data effectively. Partnering with tour operators presents a promising avenue for bridging this gap, facilitating scientific exploration while engaging and educating tourists about the region's ecological significance.

This proposal underscores the indispensable role of citizen science in advancing sustainable Antarctica tourism, laveraging Antarctica21's onboard programs as a case study. By integrating various citizen science initiatives into its expedition, Antarctica21 has empowered passengers to actively contribute to scientific research and environmental monitoring efforts. Programs such as FjordPhyto, Happywhale, and NASA Globe Clouds, offer participants immersive opportunities to collect data and deepen their understanding of Antarctica's ecosystems.

A central focus of this study is to highlight the transformative impact of citizen science experiences on participants. Through firsthand engagement in scientific research activities, tourists not only gain valuable insights into the region's ecological dynamics but also become advocates for sustainable tourism practices. By fostering interdisciplinary collaboration between tourism operators, scientific institutions, and local stakeholders, these initiatives pave the way for informed conservation efforts and responsible tourism practices in Antarctica.

By showcasing Antarctica21's pioneering efforts in citizen science, this case study aims to inspire dialogue and collaboration towards a more sustainable future for Antarctic tourism, grounded in scientific inquiry and public engagement.

This revision emphasizes the crucial role of science in understanding and mitigating the impacts of human activities in Antarctica, highlighting the importance of partnership between tour operators and scientific institutions for effective research and conservation efforts.

212

ACTIVE LAYER THERMAL PROFILE DIFFERENCES BETWEEN SYNGENETIC AND EPIGENETIC PERMAFROST, CAPE WELCHNESS, DUDEE ISLAND, ANTARCTICA

Geólogo Adrián Silva Busso¹, Geólogo Aitor Ormazabal²

¹Instituto Antartico Argentino, San Martín, Argentina. ²Universidada Buenos Aires, Buenos Aires, Argentina

Abstract

Cape Wellchness is located on the west coast of Dundee Island, in the northeastern sector of the Antarctic Peninsula. This site is uncovered by ice, but largely covered by glacial and glacio-fluvial deposits of Holocene age that rest on the sediments of the Gustav Group and the Trinity Group. Syngenetic and epigenetic cryounits have been detected. The lateral moray eel is syngenetic and has a high ice content between 40-85% depending on the orientation of its slopes. The lowland plain is one of the most widespread epigenetic units and has an ice content that increases in depth between 6% - 16% (Silva Busso y Moreno Merino, 2024). In order to detect the thawing depth of the active layer, two CALM-type boreholes have been installed in both cryounits, where a garland of 5 thermometers (Wire-iButton thermometers) located every 0.2 m between the depths of 0.2 and 1.00 m was installed. These devices took temperature data every hour during 03/06/2022 to 01/24/2023 with an accuracy of +/-0.25°C. The information from the thermometers was reviewed and it was detected that in the CALM-morena station the 0°C isotherm is located at 0.8m throughout the summer, which indicates that the thawing effectively reaches 0.6m depth. The CALM-Low Plain station has an isotherm of 0°C, at 1.00m throughout the summer, which indicates that the thawing effectively reaches 0.9m. This information makes it possible to interpret different active layer thawing conditions for different cryounits, an important factor in guiding active layer monitoring and understanding the heat distribution between different cryounits in permarost.

Silva Busso, A., and Moreno Merino L. 2024. Permafrost and Hydrogeology of Quaternary deposits at Cape Wellchness, Dundee Island, Antarctica. Antarctic Science (in press).

213

Addressing Equality, Diversity and Inclusion from within the Scientific Committee on Antarctic Research

Mx Pilvi Saarikoski¹, Dr Adriana Gulisano^2,3,4, Dr Jilda Caccavo^5,6, Dr Inga Beck⁷

¹British Antarctic Survey, Cambridge, United Kingdom. ²Departamento de Ciencias de la Atmosphera, Instituto Antarctico Argentino, Buenos Aires, Argentina. ³Institute for Astronomy and Space Physics (IAFE), CONICET-UBA, Buenos Aires, Argentina. ⁴Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, Buenos Aires, Argentina. ⁵Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Paris, France. ⁶Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques, LOCEAN/IPSL, UPMC-CNRS-IRD-MNHN, Sorbonne Université, Paris, France. ⁷Scientific Committee on Antarctic Research, Cambridge, United Kingdom

Abstract

The Scientific Committee on Antarctic Research (SCAR) created a scoping group in 2020 to begin discussions on how to approach issues of equality, diversity, and inclusion (EDI) in SCAR and the wider Antarctic research community. The key suggestion to SCAR representatives from the scoping group was to establish a SCAR EDI Action Group (AG) to address EDI challenges. The remit of the Action Group is to improve understanding of EDI challenges within the context of SCAR, and translate that understanding into activities and actions to improve accessibility and representation within Antarctic research. The SCAR EDI AG was approved in 2021 and began operating in May 2021. In our talk, we present the SCAR EDI AG organisation, goals, completed and planned activities, as well as outlooks for further conversation with the community.

215

AN INDIVIDUAL-BASED MODEL (IBM) OF ANTARCTIC KRILL (EUPHAUSIA SUPERBA) SWIMMING BEHAVIOUR: FROM EXPERIMENTAL OBSERVATIONS TO A WORKING MODEL

Dr Nicole Hellessey¹, Dr Nicholas Record¹, Dr David Fields¹, Dr David Murphy², Dr Kuuvat Grayev², Ms Carlyn Scott², Prof Marc Weissburg³

¹Bigelow Laboratories for Ocean Sciences, East Boothbay, USA. ²University of South Florida, Tampa, USA. ³Georgia Institute of Technology, Atlanta, USA

Abstract

Antarctic krill (Euphausia superba) are vital to the Southern Ocean ecosystem, with their swarming behaviours key to their ability to forage and avoid predators. Knowing how environmental drivers change krill swarming behaviour to predict their distribution and abundance for ecosystem models and fisheries management is key. An Individual-Based Model (IBM) was created for krill based on experimental observations taken at a range of different flows (0, 0.6, 3, 5.9 and 8.9 cm s^-1), light (surface and 100 m depth) and chemical cue (chlorophyll – a positive attractant and guano – a negative attractant) conditions. 3-dimensional tracks of krill were collected via video analysis and used to generate the distributions and correlations seen within the model. A Random Forest model was used on each of the swimming behaviour parameters (e.g., velocity, bimodal swimming, turn angles, edge effects, and pitch) to find which environmental variables had the biggest effect on each aspect of krill behaviour. A flat torus IBM was generated and ground-truthed to the observed data in control conditions before each environmental variable was added and the model expanded to include additional individuals and their interactions (such as nearest neighbour distance). The IBM will be scaled up and overlaid onto oceanographic models to predict krill swarming behaviour and dynamics. This is the first time that krill behaviour has been used to look at the dynamics and swarm structure of krill. Our IBM will greatly improve current ecosystem models and fisheries management decisions in the Southern Ocean.

219

Information and disinformation on Antarctica’s fate, 1948-1958:Perceptions from Chilean diplomat Mario Rodríguez

Dr. Consuelo Leon

Centro de Estudios Hemisfericos y Polares, Vina del Mar, Chile

Abstract

The decision-making process regarding Antarctica, during the first decade of the cold war, was not easy to handle for Chilean authorities. At that time, there was not much reliable information about the international projects for the frozen continent, which -at least in part- was understood as an integral part of Chile’s national territory.

During this period, the Chilean Ministry of Foreign Affairs had to take into consideration some important factors: first, the armed forces’ viewpoint, which, to an important extent, was represented by figures such as General Ramón Cañas and Admiral Rafael Santibáñez; second, the advice of international law experts who were part of the same Ministry; third, the ups and downs of domestic and regional politics during the consolidation of the cold war; and fourth, the opinions of Chilean diplomats who, from abroad, tried to assert their views. Of particular interest is Mario Rodríguez, ambassador to the United States, whose thinking deserve a deeper analysis. His perspectives, as well as those by other Chilean diplomats in the foreign service, seem not to have been understood among the country’s authorities which, possibly, explains the decisions made in 1959.

This work is based on American and Chilean official documents and aims to analyze the perceptions and suggestions made by Mario Rodríguez during his tenure as Chilean Ambassador to the United States

220

Antarctic and Greenland ice sheets 'weather' versus 'climate' timescales of variability from days to millennia

Prof Edward Hanna

University of Lincoln, Lincoln, United Kingdom

Abstract

The variability of the Antarctic and Greenland ice sheets occurs on various timescales and crucially influences sea-level rise; however, substantial uncertainties remain concerning future ice-sheet mass changes. Here we examine the extent to which short-term fluctuations and extreme glaciological events reflect the ice sheets’ long-term evolution and ongoing response to climate change. Short-term (decades or less) variations in atmospheric or oceanic conditions can trigger amplifying feedbacks that make the ice sheets more sensitive to climate change. For example, variability in ocean-induced and atmosphere-induced melting can trigger ice thinning, retreat and/or collapse of ice shelves, grounding-line retreat, and help accelerate ice flow. The Antarctic Ice Sheet is particularly vulnerable to increased melting and ice sheet collapse induced by warm ocean currents, and this effect could be enhanced with increased climate variability. Greenland has experienced notably high and low melt anomalies in the last few decades, especially since 2012, highlighting the influence of increased interannual climate variability on extreme glaciological events and ice-sheet evolution. Failing to adequately account for such variability may can result in biased projections of multi-decadal ice mass loss. Therefore, future research priorities are improving climate and ocean observations and models, and developing sophisticated ice sheet models that are directly constrained by observational records and can capture ice dynamical changes across various timescales. These critical research efforts are supported by the World Climate Research Programme's Climate and Cryosphere project in collaboration with SCAR and other international partners.

221

The importance of dispersal when considering population dynamics of a long-lived seabird, the emperor penguin.

Ms Rose Foster-Dyer¹, Dr David Iles², Dr Stephanie Jenouvrier³, Dr Sara Labrousse⁴, Dr Leonardo Salas⁵, Dr David Ainley⁶, Mr David Ortega⁷, Ms Lise Viollat³, Dr Gerald Kooyman⁸, Dr Barbara Wienecke⁹, Dr Paul Ponganis⁸, Dr Peter Fretwell¹⁰, Dr Phil Trathan¹⁰, Dr Christophe Barbraud¹¹, Dr Carolynne Hultquist¹, Dr Michelle LaRue¹

¹University of Canterbury, Christchurch, New Zealand. ²Canadian Wildlife Service, Ottawa, Canada. ³Woods Hole Oceanographic Institute, Woods Hole, USA. ⁴Sorbonne University, Paris, France. ⁵Point Blue Conservation, Petaluma, USA. ⁶HT Harvey & Associates, Los Gatos, USA. ⁷Univeristy of Minnesota, Minnesota, USA. ⁸Scripps Oceanographic Institute, La Jolla, USA. ⁹Australian Antarctic Division, Hobart, Australia. ¹⁰British Antarctic Survey, Cambridge, United Kingdom. ¹¹CEBC, Villiers en Bois, France

Abstract

Emperor penguin (Aptenodytes forsteri, EMPE) populations in the Ross Sea are known to fluctuate considerably interannually, though the cause of these fluctuations is largely unknown. To understand the drivers of EMPE population dynamics in the Ross Sea, we assessed population sizes at each of the seven colonies over a ~14-year period (2005-2018) using very-high resolution satellite imagery, aerial counts and a Bayesian state space approach. We employed a generalised additive modelling approach to assess the growth rates of each colony against an array of biotic (e.g., rate of change within different radii (100km–1100km) and colony size) and abiotic (e.g., fast ice persistence, SIC anomalies, ENSO and SAM) covariates to determine the drivers of population change. We also assessed patterns of covariation that may indicate inter-colony dispersal. We found increasing populations at Capes Crozier (R² = 0.88, P <0.001, Estimate = 60.22) and Colbeck (R² = 0.32, P = 0.03, Estimate = 265.2), and decreasing at Beaufort Island (R²= 0.59, P <0.001, Estimate = -16.93). The best-fit model combined both abiotic and biotic factors and included regional winter sea ice concentration anomalies, 1-year lagged ENSO, and the rate of change at colonies within 1100km (the maximum distance between any colony pair in the Ross Sea; adj. R² 0.803, dev. expl. 83.1%, AICc -344.16). We found model performance increased considerably when the rate of change at surrounding colonies was included (Abiotic only best-fit: R²adj. 0.355, dev. expl. 41.8%, AICc -243.66). Our findings highlight the importance of considering beyond a single colony to accurately assess population change. We postulate that Ross Sea EMPE populations may display less site fidelity than previously suggested, possibly choosing breeding location based on a variety of factors and temporarily dispersing interannually across the region.

222

Subglacial Conditions Beneath the Central Flow Line of Thwaites Glacier: Wetness and Roughness

Dr Felipe Napoleoni¹, Dr Alex M. Brisbourne², Dr. Rebecca Schlegel³, Dr. Julien A. Bodart¹, Ms Helen Ockenden¹, Prof. Robert G. Bingham¹

¹University of Edinburgh, Edinburgh, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Tübingen, Tubingen, Germany

Abstract

International collaborative efforts have yielded crucial insights into the subglacial conditions beneath the central flow line of the Thwaites Glacier. This research aims to enhance our understanding of how the ice sheet, on a broader scale, flows from the higher regions of the continent towards the margins. The acquired information not only sheds light on the complex processes within the ice column at a more detailed scale but also provides fundamental insights into the dynamic ice flow over key regions in Antarctica. These regions, exemplified by the Thwaites Glacier, are anticipated contributors to short-to-midterm sea-level rise. In this presentation we present new perspectives on the subglacial conditions of the Thwaites Glacier's central flow line. We will also delve into aspects such as subglacial hydrology and internal deformation of the ice column. Furthermore, the discussion will explore the implications of this newfound knowledge for the improvement of ice sheet numerical models and the reduction of uncertainties in sea-level rise projections.

224

Variable and homogeneous selection simultaneously shape microdiverse bacteria in an Antarctic wetland complex

María Victoria Quiroga¹, James C. Stegen², Gabriela Mataloni³, Don Cowan⁴, Pedro H. Lebre⁴, Angel Valverde⁵

¹Instituto Tecnológico de Chascomús (CONICET-UNSAM); Escuela de Bio y Nanotecnologías (UNSAM), Buenos Aires, Argentina. ²Pacific Northwest National Laboratory, Ecosystem Science Team, Richland, WA, USA. ³Instituto de Investigación e Ingeniería Ambiental (IIIA, CONICET-UNSAM), San Martín, Argentina. ⁴Centre for Microbial Ecology and Genomics (CMEG), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa. ⁵Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA), Consejo Superior de Investigaciones Científicas (CSIC), Salamanca, Spain

Abstract

Eco-evolutionary processes shaping Antarctic microbial communities are driven by selection pressures imposed by Antarctica’s extreme environmental conditions. A previous study of the bacterial assemblages in a complex of small wetlands (Cierva Point Wetland Complex - CPWC) revealed that they are shaped by strong homogeneous selection, but did not identify either which phylogenetic clades were submitted to those selection processes or the ecological strategies allowing them to thrive in such extreme conditions. Here, we approached these questions by applying the phyloscore and feature-level βNTI indexes coupled with phylofactorization. In this way, bacterial monophyletic clades subjected to homogeneous (HoS) and heterogenous (HeS) selection were detected. Remarkably, only the HoS clades showed high relative abundance across all samples and signs of putative microdiversity. Most amplicon sequence variants (ASVs) within each HoS clade clustered into a unique 97% sequence similarity operational taxonomic unit (OTU) and inhabited a specific environment type (i.e., lotic, lentic, or terrestrial). Our findings suggest that microdiversification leads to sub-taxa niche differentiation, with putative distinct ecotypes (i.e., groups of ASVs) adapted to a given environment type. We hypothesize that HoS clades thriving in the CPWC have phylogenetically conserved traits that accelerate their rate of evolution, which facilitate microdiversification through enabling rapid adaptation to strong, spatio-temporally variable selection pressures. Remarkably, both selection processes appear to operate simultaneously but on different ecological levels of organization, with homogeneous selection detected at the community level, and variable selection influencing microdiversity at the population level. Our study highlights the importance of simultaneously assessing biodiversity patterns at taxa and sub-taxa levels to understand the eco-evolutionary processes shaping CPWC microbial communities. Also, as it is unknown whether other systems experience this dynamics, it calls for comparable studies elsewhere in Antarctica.

226

Entrained water in basal ice suppresses radar bed-echo power at the active subglacial lakes of Whillans Ice Plain, West Antarctica

Benjamin Hills¹, Matthew Siegfried¹, Dustin Schroeder²

¹Colorado School of Mines, Golden, USA. ²Stanford University, Palo Alto, USA

Abstract

The hundreds of subglacial lakes which underlie the Antarctic ice sheet are important for understanding glaciological processes such as basal lubrication and ice dynamics as well as subglacial hydrological processes such as biogeochemical cycling and discharge of freshwater and sediment into the ocean. These subglacial lakes have been mapped across the continent primarily through two observational methods, radio-echo sounding (RES) and surface deformation. At sites where both observations are coincident, the datasets provide conflicting interpretations about the ice-bed interface. With a single exception, “active” subglacial lakes identified by surface deformation of the overlying ice do not display the expected flat, bright, and specular bed reflection in RES data as is characteristic of "non active" or "stable" lakes (e.g., Lake Vostok). This discrepancy between observations suggests that our physical understanding of Antarctic subglacial hydrology, especially beneath fast-moving ice streams and outlet glaciers, remains incomplete. Here, we use data from an airborne RES campaign that surveyed a well-characterized group of active subglacial lakes on lower Mercer and Whillans ice streams to explore the inconsistency between the two observational techniques. In particular, we test hypotheses of increased scattering and englacial attenuation due to the presence of an active subglacial lake system that could suppress the reflected bed-echo power for RES observations in these locations. Based on our results, we argue that entrained water in the basal ice is both scattering and attenuating the radar echo, making the lake echoes on average dimmer than the grounded non-lake regions of the survey. We argue that this phenomenon is unique to active subglacial lakes, where pressurization associated with the filling and/or draining of a lake forces water into the basal ice.

228

Variability in Antarctic krill transport pathways in the Atlantic sector of the Southern Ocean: Results from high resolution model simulations.

Cian Kelly^1,2, Ingrid Ellingsen², Ragnhild L. Daae², Morten O. Alver¹

¹NTNU, Trondheim, Norway. ²SINTEF Ocean, Trondheim, Norway

Abstract

Antarctic krill (Euphausia superba) play a crucial role in the Southern Ocean ecosystem where they are an important prey item for marine predators such as marine mammals and fish, form dense swarms that forage and graze on phytoplankton, and produce large, fast sinking fecal pellets that contribute to the biological pump. Understanding the transport patterns of Antarctic krill is key to forecasting changes in distribution and abundance in a rapidly warming environment.

As part of the SFI Harvest project (https://sfiharvest.no/) at NTNU and SINTEF we are developing an individual-based model of Antarctic krill in the Southern Ocean. The individual-based model is coupled to an ocean model called SINMOD that simulates currents, temperature, salinity and ice dynamics in the Atlantic Sector of the Southern Ocean. The model is run with a time step of 4 minutes, comprised of a regular grid with cells of 4000 x 4000m resolution and 41 depth layers, depending on surface elevation, where layers are thicker at depth than at the surface.

The objective of the work is to study dominant transport pathways in the region and resolve how both abiotic and biotic factors can influence these pathways. Early simulations indicate topographic steering is central in determining transport in these regions. There is relatively high connectivity between the Antarctic Peninsula (a key spawning region and source of Antarctic krill) and the South Orkney Islands. However, there is relatively low connectivity between both these regions and South Georgia, which is known as a net sink for Antarctic krill. A key question surrounds the origin and drivers of interannual variability in South Georgia krill biomass. Another is the impact of diel vertical migration on dominant pathways between these regions.

229

Direct expansion convectively-isolated radiant heating panels for Antarctic thermal comfort

Dr. Eric Teitelbaum

AIL Research, Inc., HOPEWELL, USA

Abstract

In the warming world, a need for thermal refuge from a heat stress inducing environment is becoming increasingly important. An all-radiant approach to this need has been developed, whereby radiant cooling provided by chilled surfaces isolated from the warm and often humid air can efficiently remove heat from occupants to create the sensation of thermal comfort in otherwise overly hot environments. The most recent embodiment of this project is a direct expansion radiant cooler, whereby a large flat plate evaporator is chilled, rejecting heat back to the air much like a refrigerator.

In the Antarctic, there is an opportunity for the same technology to work in reverse--a direct expansion, convectively isolated all-radiant heater to act as a spot heater to improve thermal comfort sensations in environments where the air temperature cannot be maintained at thermally acceptable conditions. The use of a thermally transparent membrane that enables radiant heat transfer but eliminates convective heating of the air by isolating the hot, flat plate condenser, can efficiently source heat from the air or sun (when available) and radiantly heat occupants.

In this study, Antarctic operation of this novel heat pumping system will be modeled to demonstrate comfort ranges of the technology. Based on the authors' expanded psychrometrics framework, independent manipulation of air temperature and radiant temperature is parameterized, and used to characterize the performance of the generated thermal environment over a range of Antarctic heat sourcing temperatures.

235

Assessing Availability and Potential Toxicity of Trace-element Contaminants in Permafrost Soils from two Antarctic Ecosystems (Deception and Livingston Islands)

Catarina Louro¹, Henrique Zilhão^1,2, Rodrigo Dias^1,3, Susana Sousa Gomes⁴, Maria Fátima Araújo^4,5, Gonçalo Vieira², Rute Cesário¹, Rodrigo Costa³, João Canário¹

¹Centro de Química Estrutural, Institute of Molecular Sciences, Department of Chemical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal. ²Centro de Estudos Geográficos, Laboratório Associado TERRA, Instituto de Geografia e Ordenamento do Território, Universidade de Lisboa, Lisbon, Portugal. ³iBB—Institute for Bioengineering and Biosciences and i4HB—Institute for Health and Bioeconomy, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal. ⁴Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Lisbon, Portugal. ⁵Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Lisbon, Portugal

Abstract

Chemical and biological characterisation of Antarctic permafrost soils remains insufficiently studied. To bridge these knowledge gaps, soil samples from the active layer down to the permafrost table were collected in Deception and Livingston islands, South Shetlands archipelago (Maritime Antarctica). The aim of this work was to characterize the trace-element content, their chemical availability, and potential toxicity related with microbial transformations. For that, samples were digested with a mixture of acids for contaminant content (e.g. arsenic, cadmium, mercury) and sequential extractions were used to investigate their chemical availability. To assess the toxicity potential of these samples, their genetic material was extracted and submitted to 16S rRNA gene sequencing, and PCR detection of As and Hg methylation genes (arsM and hgcAB, respectively), which may contribute to increase (Hg to methylmercury) or decrease (As to dimethylarsenic) toxicity. Results showed relatively higher concentrations of total mercury and arsenic in Deception Island, possibly due to the existence of active volcanic sources. Data from the sequential extractions point to the presence of contaminants that are easily released with changes of pH commonly found near active fumaroles (e.g. Ni), or changes in redox potential due to the percolation of water (e.g. As). These indicate possible niches for microbially-mediated Hg and As methylation in the studied soils. This hypothesis will be addressed via molecular characterization of the microbiomes in the analysed samples.

The present work shows that thawing permafrost might potentially impact these ecosystems, especially considering the mobilisation of elements and the increased toxicity, posing potential environmental risks to Maritime Antarctica wildlife.

240

New insights into the Weddell Sea ecosystem applying a quantitative network approach

Dr Tomás Ignacio Marina¹, Dr Leonardo A. Saravia^1,2, Dr Susanne Kortsch³

¹Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina. ²Universidad Nacional de Tierra del Fuego (UNTDF), Ushuaia, Argentina. ³University of Helsinki, Hanko, Finland

Abstract

Network approaches can shed light on the structure and stability of complex marine communities. In recent years, such approaches have been successfully applied to study polar ecosystems, improving our knowledge on how they might respond to ongoing environmental changes. The Weddell Sea is one of the most studied marine ecosystems outside the Antarctic Peninsula in the Southern Ocean. Yet, few studies consider the known complexity of the Weddell Sea food web, which in its current form comprises 490 species and 16 041 predator–prey interactions. Here we analysed the Weddell Sea food web, focusing on the species and trophic interactions that underpin ecosystem structure and stability. We estimated the strength for each interaction in the food web, characterised species position in the food web using unweighted and weighted food web properties, and analysed species’ roles with respect to the stability of the food web. We found that the distribution of the interaction strength (IS) at the food web level is asymmetric, with many weak interactions and few strong ones. We detected a positive relationship between species median IS and two unweighted properties (i.e. trophic level and the total number of interactions). We also found that only a few species possess key positions in terms of food web stability. These species are characterised by high median IS, a middle to high trophic level, a relatively high number of interactions, and middle to low trophic similarity. In this study, we integrated unweighted and weighted food web information, enabling a more complete assessment of the ecosystem structure and function of the Weddell Sea food web. Our results provide new insights, which are important for the development of effective policies and management strategies, particularly given the ongoing initiative to implement a marine protected area (MPA) in the Weddell Sea.

241

Team Polar: Developing an electric and autonomous vehicle for safer Antarctic research

Ignacio Becerra Osorio^1,2, Uko Pallum^3,2, Mick Schüssel^1,2, Cas van Hees^1,2

¹Eindhoven University of Technology, Eindhoven, Netherlands. ²Team Polar, Eindhoven, Netherlands. ³Eindhoven University of Technology, EIndhoven, Netherlands

Abstract

Team Polar is a student team from Eindhoven University of Technology (TU/e) with members from different majors and countries. The team is developing an autonomous and self-sufficient vehicle for Antarctic researchers to help facilitate research in dangerous and inaccessible areas. This development is done in collaboration with advisors from the industry to encourage the implementation of novel technologies.

The team’s first prototype rover, called the Ice Cube, underwent its first test in the Norwegian snow in January 2023. The team is currently working on a second prototype to further develop the cold-climate operation abilities of the vehicle which will eventually lead to a modular vehicle that can aid researchers by autonomously carrying out measurements for them in the vicinity of several hundred kilometers of a research station. In order to demonstrate this technology, the team is in the work of setting up a collaboration agreement with an Antarctic research organization and the development of the rover is being tailored towards their intended application area.

The new rover will have autonomous capabilities based on sensor input and algorithms. The algorithms determine the optimal route of the vehicle between points based on the Reference Elevation Model of Antarctica (REMA) with a GPS module. Cameras, ground penetrating radar, and a lidar sensor will be implemented to find obstacles and adjust the route of the rover.

The team is looking for experts in the field of cold-climate engineering to aid us in our development, and welcome new ideas on how our vehicle might provide value to the polar research community.

242

Team Polar: Developing an electric and autonomous vehicle for safer Antarctic research

Ignacio Becerra Osorio^1,2, Mick Schüssel^1,2, Uko Pallum^1,2

¹Eindhoven University of Technology, Eindhoven, Netherlands. ²Team Polar, Eindhoven, Netherlands

Abstract

The team’s first prototype rover, called the Ice Cube, underwent its first test in the Norwegian snow in January 2023. The team is currently working on a second prototype to further develop the cold-climate operation abilities of the vehicle that will eventually lead to a modular vehicle that can aid researchers by autonomously carrying out measurements for them in the vicinity of several hundred kilometers of a research station. In order to demonstrate this technology, the team is in the work of setting up a collaboration agreement with an Antarctic research organization and the development of the rover is being tailored towards their intended application area.

The new rover will have autonomous capabilities based on sensor input and algorithms. The algorithms determine the optimal route of the vehicle between points based on the Reference Elevation Model of Antarctica (REMA) with a GPS module. Cameras, a ground penetrating radar and a lidar sensor will be implemented to find obstacles and adjust the route of the rover.

The team is looking for experts in the field of cold-climate engineering to aid us in our development, and welcome new ideas on how our vehicle might provide value to the polar research community.

244

The effects of life stage on Antarctic krill faecal pellet attenuation

Ms Anona Griffiths¹, Dr Angus Atkinson², Dr Simeon Hill³, Dr Emma Cavan¹

¹Imperial College London, London, United Kingdom. ²Plymouth Marine Laboratory, Plymouth, United Kingdom. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Antarctic krill have a huge biomass which underpins their significant contribution to the Southern Ocean’s biological carbon pump. However, there is a gap in knowledge on the relative importance of different life stages. Here, we address this by assessing the impact of life stage (larvae, juveniles postlarvae, and adults) on krill particulate organic carbon (POC) flux in the form of faecal pellets, exuviae and carcasses. We conducted lab-based experiments which revealed differences in average sizes, sinking rates and attenuation of pellets among different life stages. We then combined these results with literature estimates of intermoult period and larval exuviae masses to produce life-stage-specific estimates of POC flux. Our research highlights spatial variability in POC flux processes across South Georgia, the South Orkney Islands, and the Western Antarctic Peninsula, related to differences in the abundance of the three life stages. By combining POC flux estimates, attenuation estimates and ocean dynamics, we provide estimates of the amount of krill carbon that is sequestered for >100 years. Our evaluation of the impact of krill life history on long-term carbon storage will help to identify the locations to prioritise for protection.

246

Antarctic Wetlands conceptualization and characterization for better protecting key biodiversity hotspots

Valeria Casa¹, María Victoria Quiroga², Paulina Fermani³, Yanina Sica¹, Ruben D Quintana¹, Marcela M Libertelli⁴, Gabriela Mataloni¹

¹Instituto de Investigación e Ingeniería Ambiental - IIIA, UNSAM, CONICET, 3iA, San Martín, Argentina. ²Instituto Tecnológico de Chascomús (CONICET-UNSAM); Escuela de Nano y Biotecnologías (UNSAM), Chascomús, Argentina. ³Laboratorio de Microbiología Ambiental (CESIMAR-CONICET/IBIOMAR-CONICET), Puerto Madryn, Argentina. ⁴Departamento de Biología de los Predadores Tope, Coordinación Ciencias de la Vida, Instituto Antártico Argentino, San Martín, Argentina

Abstract

Wetlands are ecosystems wherein the temporary or permanent presence of water renders biogeochemical fluxes different from those of terrestrial and freshwater ones, and forces the biota to adapt to such variable conditions. These particular ecosystem structure and functioning have generated a distinct paradigm for their study, conservation and management. Wetlands are distributed worldwide, including Antarctic ecoregions. Indeed, some ecosystems in McMurdo Dry Valleys, Byers Peninsula and Soya Coast were properly named as wetlands, but mostly analysed under limnological paradigms.

Although globally recognised as biodiversity hotspots and key providers of ecosystem services, fast degradation and disappearance of wetlands prompted the Ramsar Convention as the Intergovernmental treaty for their conservation. Still, as this requires contracting national parties to make sovereign management decisions on protected areas, the Antarctic Treaty System precludes nomination of Ramsar-protected Antarctic wetlands. Nor does the Madrid Protocol include them among the ecosystems meriting nomination of Antarctic Specially Protected Areas (ASPAs).

Cierva Point is located within ASPA Nº134, so nominated due to its exceptional biodiversity. Its topographically complex North face is dominated by a plethora of small wetlands. During 2017-2018 we geolocated 66 wetlands and classified them into nine types. Then we analysed the contribution of the wetland type, geomorphological site properties (location, exposure, dominant substrate, influence of penguin colonies) and physical-chemical features to their environmental characterization through two Principal Component Analyses. Although the variables selected in each PCA explained a high percentage of the variance, the resulting ordinations were different and neither grouped wetlands of the same type. Rather, distinct combinations of these features define Cierva Point as a wetland mosaic hosting a rich environmental diversity expressed as a biodiversity hotspot. As the ecological complexity and uniqueness of wetlands largely explains their outstanding diversity, we recommend the specific paradigms pertaining them be embraced in their future study and conservation.

250

Music, sound and well-being among members of the 1^st Japanese Antarctic Expedition

Seira Duncan¹, Dr. Rupert Summerson²

¹International Arctic Science Committee, Akureyri, Iceland. ²University of Melbourne, Melbourne, Australia

Abstract

The past decade has seen a growing interest in music and sound pertaining to the Antarctic (Hince et al 2015; Philpott 2013) and the importance of music in sustaining well-being in Antarctica (Smith 2020; Giles 2015; Watson 2015; Adams 2010). Barring Summerson (2015), little attention has been paid to non-Western experiences of music and sound in Antarctica as well as to the impacts of music and sound on the well-being of an expedition crew. This paper explores the musical and sonic experiences and related emotions of the members of the 1^st Japanese Antarctic Expedition outlined in musician Keiichi Tada’s diary (Tada 1912). References to silence, sound, poetry and music – of which there are many – are analysed in relation to comments and observations of the crew made by Tada. Additionally, he commented on natural soundscapes in the Antarctic and wrote poetry and music on board (including songs written overnight to boost team morale). There is ample mention of a gramophone with which the crew listened to traditional Japanese music and a shakuhachi (a Japanese bamboo flute) which Tada frequently practiced in the evenings. One section named Gramophone damaged recounts the moment the mainspring was damaged, followed by Tada’s personifying commentaries that ‘our only comforter is injured’, it ‘sustained a life-threatening injury’ and ‘retired’ until it was repaired in New Zealand. Tada continues that ‘we the gramophone crew were despondent and the gramophone was a major comforter for us the past two years’. Tada’s description of music as the only comforter is reflected in other social interactions on the expeditions. As such, this paper aims to contribute to existing research on primarily Western experiences of music and sound in Antarctica and to highlight the historical and potential roles of music and sound on the well-being of Antarctic researchers.

251

Wildlife from space: state-of-the-art AI approaches to identifying and counting polar wildlife in remotely sensed imagery.

Dr Peter Fretwell¹, Dr Ellen Bowler¹, Ms Penny Clarke^1,2, Dr Connor Bamford¹, Ms Tara Cunningham^1,2, Ms Holly Houliston^1,3, Dr Hannah Cubaynes¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of Edinburgh, Edinburgh, United Kingdom. ³Cambridge University, Cambridge, United Kingdom

Abstract

Over the last ten years, there has been an increasing use of remotely piloted aircraft systems and satellite remote sensing platforms to monitor polar wildlife. The large volumes of data collected by such platforms necessitate the use of machine learning to automate the process of finding and counting wildlife in the imagery. There are several distinct on-going research projects led by the British Antarctic Survey (BAS) that deal with automated counting of a range of polar predators including penguins, whales, walrus, albatrosses, and seals. Several projects involve training neural networks to identify and count individual animals in imagery, using a range of frameworks such as YOLO, DINO,CO-DETR and UNet. These projects face similar problems of sparse and variable training data, and implementing pipelines to run very large datasets through bespoke processing methodologies. Other foci include the application of spectral classifiers on multi-temporal Sentinel-2 and PlanetLabs data to identify walrus haul-out sites and emperor penguin colonies. These two research streams often return data of variable quality and inconsistent temporal usability, from which ecological information must be subsequently extracted by applying a variety of bias, shifts and statistical processes.

The Wildlife from Space Centre at BAS is in a unique position, collaborating internally with BAS biologists, statistical ecologists, remote sensing experts and the AI lab, and externally with a number of UK universities, research groups and NGO’s including the Alan Turing Institute and the AI4ER and SENSE centres for doctoral training. This collaborative approach and strong links with many international partners in Antarctica and over a wider global context allowing BAS to bring world-leading skills and unrivalled expertise in wildlife remote sensing into a broader sphere. Here we present an overview of the current machine learning projects and showcase a number of specific examples on whales, seals, walrus, penguins and albatrosses.

252

_{A fifteen-year assessment of emperor penguin populations in the region from the Bellingshausen Sea to the Weddell Sea, based on VHR satellite imagery.}

Dr Peter Fretwell¹, Dr Phil Trathan², Ms Aliaksandra Skachkova³, Dr Connor Bamford³, Dr Jaume Forcada³

¹Cambridge, Cambridge, United Kingdom. ²University of Southampton, Southampton, United Kingdom. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Recent analyses of emperor penguin populations from pan-Antarctic VHR satellite imagery (LaRue et al 2024) have shown a reduction in numbers between 2009 and 2018, when colonies become visible to satellites in the Antarctic spring. Here we extend the record to 2023 for the sixteen colonies located between 0° and 90° West for which we have consistent data. This provides a 15-year record and includes the recent period of rapid sea ice decline in the region, as well as the long-term decline reported previously. Our new record shows an overall decline in emperor numbers with a distinct downturn after 2018.

The accuracy of satellite estimates has been questioned in recent work, highlighting that supervised classification methods give poor quality population data. This results from the variability in huddle density which can be environmentally driven, or differences in adult attendance due to the timing of the imagery in comparison to breeding phenology. However, for most colonies, satellite remote sensing remains the only viable method of monitoring. Satellite archives exist for most of the known breeding sites, albeit in some cases with only a limited number of suitable images. Here we compare area of penguins, rather than estimated population and report the results of 194 satellite assessments in this sector over the 15 year period. We show that despite highly variable data, a statistically significant negative trend exists in the numbers of emperor penguins. Finally, we look to future technological improvements in monitoring emperor penguins using remote sensing, suggesting three possible alternative methodologies.

255

The breeding distribution and habitat use of the snow petrel (Pagodroma nivea), the world’s most southerly breeding vertebrate

Ms Josie Francis¹, Dr Ewan Wakefield¹, Dr Stewart Jamieson¹, Dr Dominic Hodgson², Dr Richard Phillips², Dr Colin Southwell³, Dr Louise Emmerson³, Dr Peter Fretwell², Dr Michael Bentley¹, Dr Erin McClymont¹

¹Durham University, Durham, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³Australian Antarctic Division, Kingston, Australia

Abstract

Knowledge of the spatial distribution of many polar seabird species is incomplete due to logistical difficulties of accessing remote breeding locations. Here, we compile a new database of published and unpublished records of all known snow petrel Pagodroma nivea breeding sites. We quantify local environmental conditions at these sites by appending indices of climate and substrate, and at the regional scale by appending sea-ice conditions within accessible foraging areas between 1992-2021. Snow petrels are now reported at 456 breeding sites across Antarctica and the subantarctic islands. We present a new global population estimates based on 222 sites where population data is available and estimate a minimum of ~77,400 breeding pairs. Breeding sites are close to the coast and research stations, the latter suggesting sampling bias. The median distance to the November sea ice edge (breeding season sea-ice maximum) is 430 km. Locally, most breeding pairs are located in cavities on high-grade metamorphic rocks. The most extreme (low) summer temperatures are at the most inland sites, and the highest temperatures at their northern breeding limit. Breeding location and cavity selection is likely controlled most importantly by suitable breeding substrate availability within sustainable distance of suitable foraging habitat. Within this range, cavities may then be selected based on local conditions such as cavity size and aspect. Our database will allow formal analyses of habitat selection, and provides a baseline against which to monitor future changes in the distribution of snow petrels in response to climate change.

260

Are microbes awake during the polar night? An integrated metabarcoding, metagenomics, infrared imaging study

Patricia Valdespino-Castillo^1,2,3, Ricardo Mercado-Juárez¹, Lucas Ruberto⁴, Walter Mac Cormack⁴, Luisa Falcón¹, Martin Merino-Ibarra¹, Rocío Alcántara-Hernández¹, Hoi-Ying Holman³

¹Universidad Nacional Autónoma de México, Mexico City, Mexico. ²Agencia Mexicana de Estudios Antárticos, Mexico City, Mexico. ³Lawrence Berkeley National Laboratory, Berkeley, USA. ⁴Universidad de Buenos Aires, Buenos Aires, Argentina

Abstract

Maritime and Peninsular Antarctica have one of the highest warming rates on the planet. Temperature rise impacts biodiversity, as well as ecological and biogeochemical functions. Microbes are the most diverse component of the Antarctic ecosystems. They control the flux of matter and energy in these low-temperature, low-nutrient ecosystems. Because unpredictable and severe weather, Antarctic research has focused on the summer, and our knowledge is limited regarding processes occurring during the darkest, coldest season, called the Polar Night.

We integrated metabarcoding, metagenomics, and infrared imaging to study inland microbial mats, which typically develop in streams and ponds during summertime.

Our results show that the diversity of summer microbial mats is high and activity during the polar night is constrained to a few microbial taxa. The metabolic potential differences are particularly marked between autotrophs and heterotrophs and relate to both cellular structure and function pathways. Infrared imaging results show structural and chemical differences between well-developed and early-stage ice-covered microbial mats. By understanding how Antarctic microbes respond and adapt to environmental change, we aim to help predict and mitigate the effects of Global Change.

262

Early onset of the Antarctic Cold Reversal as captured in the RICE ice core

Prof Nancy A.N. Bertler^1,2, Prof. Ed J. Brook³, Prof. Jeffrey P. Severinghaus⁴, Dr. Ruzica Dadic⁵

¹Victoria University of Wellington, Wellington, New Zealand. ²GNS Science, Lower Hutt, New Zealand. ³Oregon State University, Corvallis, USA. ⁴Scripps Institution of Oceanography, La Jolla, USA. ⁵WSL Institute for Snow and Avalanche Research, Davos, Switzerland

Abstract

The Roosevelt Island Climate Evolution (RICE) project recovered a 763.4 m deep ice core to bedrock from Roosevelt Island, at the northern edge of the Ross Ice Shelf. The ice at Roosevelt Island is grounded 210m below sea level and accumulates in situ, with the Ross Ice Shelf flowing around the rise.

Comparison of the modern RICE isotope data with meteorological records suggest that the record is representative of the temperature variability in the Ross Sea Region, the Ross Ice Shelf and western West Antarctica. In addition, the analysis shows that the RICE record is particularly sensitive to changes in regional sea-ice extent and low and mid latitude climate drivers, in particular to the combined effects of the El Niño Southern Oscillation, the Pacific Decadal Oscillation and the Southern Annular Mode¹.

Here, we show gas, isotope, geochemical and physical properties data spanning the past 65 ka and discuss reconstructions of environmental conditions and ice dynamics. The age model is based on synchronization of CH₄ and δ¹⁸Oatm records with the WAIS Divide Ice Core². High resolution CH₄ and δ¹⁵N records support analysis of precise interhemispheric phasing of events.

Our data suggest that the Ross Sea region entered conditions of the Antarctic Cold Reversal that preceded the onset Bólling Transition by ~125 years and precedes the WDC ARC onset by ~300 years. We interpret this early onset to reflect a change in atmospheric conditions that led to a reduction in snow accumulation and early, regional isotopic cooling and explore impacts on ocean currents, regional sea-ice extent, and ice sheet dynamics.

263

Dust Deposition Modulates Southern Ocean Phytoplankton Physiology and Carbon Export

Dr Jakob Weis^1,2, Dr Peter Strutton^1,2,3, Dr Zanna Chase^1,3, Dr Christina Schallenberg^4,5, Dr Andrew Bowie^1,5

¹UTAS, Hobart, Australia. ²CLEX, Hobart, Australia. ³ACEAS, Hobart, Australia. ⁴CSIRO, Hobart, Australia. ⁵AAPP, Hobart, Australia

Abstract

Southern Ocean productivity is seasonally limited by the micronutrient iron. Windblown mineral dust, a significant source of bio-available iron, has been shown to support a considerable portion of Southern Ocean productivity. However, the effect of dust-derived iron fertilisation on phytoplankton communities, key drivers of the biological carbon pump, and export production dynamics remains poorly understood. We investigated the impact of dust-iron on phytoplankton communities and carbon sequestration in the iron-limited Southern Ocean. Using bio-optical observations from BGC-Argo floats, we examined the effects of dust-iron addition on phytoplankton productivity, community structure, and carbon export dynamics. We found that increased dust deposition correlates with increased chlorophyll, particulate organic carbon (POC) and cellular pigmentation (chl:POC) in the mixed layer, indicating enhanced photosynthetic activity by phytoplankton and a shift towards diatom-dominated communities consistent with iron fertilisation. We also identified a basin-wide correlation between dust deposition and annual export production (AEP), corroborating the idea that enhanced dust deposition during glacial periods contributed to lower atmospheric CO₂ concentrations. Furthermore, regional variations in AEP were linked to subsurface iron sources, emphasising the complex interplay between atmospheric and oceanic iron inputs. These results suggest that dust-iron fertilisation not only enhances phytoplankton productivity but may also increase the efficiency of carbon export, potentially facilitating long-term oceanic carbon sequestration. This work highlights the important role of dust-derived iron in shaping the Southern Ocean's biogeochemical cycles and highlights the need for further research to understand the mechanistic links between dust deposition, phytoplankton responses, and carbon export.

264

Proposed exploration of Subglacial Lake Qilin in East Antarctica

Prof Pavel Talalay

Jilin University, Changchun, China. China University of Geosciencies, Beijing, China

Abstract

In the middle of the 2010s, interpretation of radio-echo sounding revealed a series of subparallel, narrow, and long subglacial canyons in Princess Elizabeth Land, East Antarctica, which individually extend to 545 km in length and are up to 10 km wide. The existence of a large subglacial lake in one of the canyons was suggested on the basis of subglacial hydraulic flatness, elevated basal reflectivity, and high basal specularity. The lake is estimated approximately 42 km in length and 370 km² in area, making it one of the largest subglacial lakes in Antarctica. The lake is overlain with an average ice thickness of about 3,600 m. The estimated maximal water thickness from gravity inversion in the central part of the lake is ~240 m. The measured ice temperature at the surface is about -41°C. Subglacial Lake Qilin was chosen as a candidate for exploration because the lake is (a) logistically accessible through Chinese scientific field operations (~600 km from the Chinese Zhongshan Station); (b) thought to be isolated, potentially for hundreds of thousands of years and may provide unique information about the microbial evolution, the past climate of the Earth and the formation of the ice sheet; (c) representative of many other continental interior deep subglacial Antarctic lakes, in terms of pressure and temperature conditions. The concept of the proposed exploration is based on the deep clean hot water drilling system that recently is considered as the most environmental friendly access technology. We also consider to test alternative option for subglacial exploration – RECoverable Autonomous Sonde (RECAS) that allows to drill ice downward and upward and to sample subglacial water while the subglacial lake remains isolated from the surface.

266

Testing the resilience, physiological plasticity and mechanisms underlying upper temperature limits of Antarctic marine ectotherms.

Dr simon morley¹, Prof Amanda Bates², Prof Melody Clark¹, dr elaine Fitzcharles¹, Ms Rebecca Smith¹, Ms Rose Stainthorp³, Prof Lloyd Peck¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of Victoria, Victoria, Canada. ³National Oceanography Centre, Southampton, United Kingdom

Abstract

Antarctic marine ectotherms live in the constant cold and are characterised by limited resilience to elevated temperature. Here we tested three of the central paradigms underlying this resilience. Firstly, we assessed the ability of 8 species, from 7 classes representing a range of functional groups, to survive, for 100 to 303 days, at temperatures 0 to 4 °C above previously calculated long-term temperature limits. Survivors were then tested for acclimation responses to acute warming and acclimatisation, in the field, was tested in the seastar O. validus collected in different years, seasons and locations within Antarctica. Finally, we tested the importance of oxygen limitation in controlling upper thermal limits. We found that four of 11 species studied were able to survive for more than 245 days (245 – 303 days) at higher than previously recorded temperatures, between 6 and 10 °C. Only survivors of the anemone Urticinopsis antarctica did not acclimate CT_max and there was no evidence of acclimatisation in O. validus. We found species-specific effects of mild hyperoxia (30 % oxygen) on survival duration, which was extended (2 species), not changed (4 species) or reduced (1 species), re-enforcing that oxygen limitation is not universal in dictating thermal survival thresholds. Thermal sensitivity is clearly the product of multiple ecological and physiological capacities, and this diversity of response needs further investigation and interpretation to improve our ability to predict future patterns of biodiversity.

269

Sub-ice geology, deep crustal structures, and lithosphere-cryosphere interactions at the western margin of the West Antarctic Rift System, North Victoria Land, from comprehensive analysis of combined geophysical and geological data

Antonia Ruppel¹, Maximilian Lowe^2,3, Andreas Läufer¹, Laura Crispini⁴, Nikola Koglin¹, Frank Lisker⁵, Jörg Ebbing⁶

¹Federal Institute for Geosciences and Natural Resources, Hannover, Germany. ²NERC British Antarctic Survey, Cambridge, United Kingdom. ³University of Edinburgh, Edinburgh, United Kingdom. ⁴University of Genova, Genova, Italy. ⁵University of Bremen, Bremen, Germany. ⁶Kiel University, Kiel, Germany

Abstract

Extensive magmatic activity over considerable time scales, with regional variations in magnitude and extent, is indicated by near-surface geological observations along the western margin of the West Antarctic Rift System (WARS). Late Neoproterozoic to early Paleozoic and mid-Paleozoic magmatic rocks are related to long-lasting convergence along the paleo-Pacific active continental margin of East Gondwana. Mafic intrusive and extrusive magmatism occurred during the Jurassic, associated with the breakup of Gondwana. Cenozoic plutonic and volcanic activity associated with the formation of the WARS occurs in an area characterized by enhanced geothermal heat flux, as indicated by Curie depth estimates. These findings support tomographic interpretations suggesting a thermal anomaly beneath the Transantarctic Mountains, which has influenced magmatic activity and is one of many factors that must be considered with regard to future Antarctic Ice Sheet (AIS) stability.

We present a new 3D crustal model of the western continental margin of the WARS based on joint inversion of magnetic and gravity data using “Variation of Information” algorithm incorporated in the academic software JIF3D. Analysis of regional data combined with a single inversion of a high-resolution airborne magnetic survey in a key region of the western rift margin allows a more reliable interpretation of subsurface structures. Geological field observations and ground susceptibility measurements validate the modelled results and allow the differentiation of magnetic source bodies, their assignment to individual tectonic events with magmatic activities, as well as the assignment of possible deformation sequences along major fault zones. The combination of high-resolution geophysical data and geological evidence allows the creation of a subsurface model and its link to lesser-known regions of the western rift margin. With its present-day sharp glaciated topography, this region forms a distinct boundary, delimiting the AIS in its hinterland and blocking the lateral ice flow towards the Ross Sea.

270

Antarctica soils works as a sink of atmospheric carbon in global warming scenario

Dr. Danilo Mello¹, MSc. Cássio Moquedace¹, MSc. Clara Baldi¹, Sr. Lucas Silva¹, Sr. Miguel Mendes², Dr. Márcio Francelino¹, Dr. Tiago Ferreira², Dr. José Demattê², Dr. Carlos Schaefer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade de São Paulo, Piracicaba, Brazil

Abstract

The dynamics of Soil Organic Carbon stocks (SOC stocks) in Maritime Antarctica (MA) and the Antarctic Peninsula (AP) in response to climate change scenarios remain uncertain. This understanding can reveal whether Antarctic soils and permafrost will act as a carbon sink or source. In this context, our objective was to predict the dynamics of SOC stocks, considering the projected temperature increases of 1.5°C (SSP1-2.6 scenario) as outlined by the Intergovernmental Panel on Climate Change (IPCC) for the 0-30cm soil layer. To achieve this, we utilized the largest dataset, comprising 3,500 soil samples collected in the field. Initially, we calculated the SOC stock for all samples by utilizing data on soil bulk density, soil organic carbon content, and soil thickness. Subsequently, we employed climate data from Chelsea under SSP1-2.6 scenario, net primary production, incorporated topographic variables, and applied ML techniques in our predictive model. Our results demonstrated a 27.7% increase (1.75 Teragrams) in SOC stock values compared to the present (0.50 Teragrams) with a temperature increment of 1.5°C in the most optimistic SSP scenario, with prediction performance greater than 0.50 considering Lin’s Concordance Correlation Coefficient. The increase in SOC stocks is driven by elevated precipitation rates and rising temperatures. Consequently, there is an expected expansion of ice-free areas, leading to a higher rate of colonization by plant communities. The establishment and growth of these plant communities are foreseen to contribute organic carbon to the soil. In conclusion, our results reveal that the ice-free areas of MA and the AP will act as a carbon sink, considering a temperature increase of 1.5°C (SSP 1-2.6 scenario), particularly within the 0-30cm soil layer.

272

Patagonian toothfish: demography, spawning and population structure over 25 years of the fishery at South Georgia

José Abreu^1,2, Philip R. Hollyman^2,3, C. C. G. Bamford², José C. Xavier^1,2, C. Darby⁴, Richard A. Phillips², Martin A. Collins²

¹University of Coimbra, Marine and Environmental Sciences Centre/ Aquatic Research Network, Department of Life Sciences, Coimbra, Portugal. ²British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom. ³School of Ocean Sciences, College of Natural Sciences, Bangor University, North Wales, United Kingdom. ⁴Centre for Environment, Fisheries and Aquaculture Sciences, Pakefield Road, Lowestoft, Suffolk, United Kingdom

Abstract

Patagonian toothfish (Dissostichus eleginoides) support valuable fisheries across the Southern Ocean under the management of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The fishery at South Georgia (CCAMLR sub-area 48.3) accounts for 26% of the catch of this species in the Southern Ocean over the last 25 years. Within this context, this presentation will: i) examine the effects of exploitation and changes in management of the fishery on biological traits of Patagonian toothfish, ii) provide an updated assessment of spawning dynamics, and iii) discuss the biological implications of these findings considering the current fisheries management regime. Our results show considerable spatial and temporal variability in the mean size of fish in the catch, but no evidence of a systematic decrease during the 25-year period. We also show that the changes in mean size of fish is linked to recruitment. Catch per unit effort (CPUE) dropped from 1997 to 2010, increased from then until 2017, and returned subsequently to values typical of the mid-2000s to mid-2010s. Spawning peaks in July, and occurs along the shelf-break of South Georgia, with spawning hotspots detected at Shag Rocks, midway along both the northern and southern shelf breaks, and at the eastern end of the main island. These results illustrate the role of management regulations (including depth restrictions and benthic closed areas) in limiting the impacts of commercial exploitation on this long-lived fish, which has an important role as the largest benthic predator in subantarctic ecosystem in the Southern Ocean.

273

AGATA: Antarctic Geospace and ATmosphere research - the Programme Planning Group approved by SCAR

Dr Lucilla Alfonsi¹, Prof Wojciech J. Miloch², Dr Nicolas Bergeot³

¹ROME, ROME, Italy. ²University of Oslo, Oslo, Norway. ³Royal Observatory of Belgium, Bruxelles, Belgium

Abstract

Uncaptioned visual

AGATA (Antarctic Geospace and ATmosphere research) is a new established Programme Planning Group approved by SCAR (Scientific Committee on Antarctic Research) to propose a new Scientific Research Programme (SRP) after more than 10 years from the previous initiative on similar topics. The proposed SRP will aim to gather the scientific communities working on polar regions to answering the outstanding scientific questions within atmospheric and space physics over polar regions:

How are different atmospheric layers coupled in the polar regions?
How does the upper polar atmosphere respond to increased geomagnetic activity, including energy transfer from space?
How does the whole polar atmosphere impact short- and long-term climate variations?

As the central role of the polar regions in understanding the coupling between the magnetosphere and the neutral and the ionized atmosphere (ionosphere), answering these questions will not only have implications on the understanding of processes in the polar atmosphere, but it will also greatly improve our understanding of the global atmospheric dynamics, thus contributing to the development of large-scale whole atmosphere and climate models.

AGATA will bring together communities which investigate the polar atmosphere and geospace, with a particular focus on Antarctica, but also with a bi-polar perspective. AGATA will be a coordinated, worldwide effort to monitor, investigate and better understand the physics of the polar atmosphere and the impact of the Sun-Earth interactions on the polar regions. AGATA will take advantage of existing and planned instrumentation in Antarctica, but also in the Arctic and satellite-based observations, and it will aim for coordinated research efforts and data exchange. AGATA will also be important for sciences that depend on the removal and mitigation of negative effects of the atmosphere on their observations (such as, e.g., radio astronomy and geodesy). To learn more you can visit the AGATA web pages: www.scar.org/science/agata/home/

274

Extreme compound events triggered by an atmospheric river in the Antarctic Peninsula during mid-austral winter 2023: Observational evidence and climatic implications

Deniz Bozkurt^1,2, Jorge F. Carrasco³, Raúl R. Cordero⁴, Francisco Fernandoy⁵, Álvaro G. Gómez⁶, Benjamín Carrillo³, Bin Guan⁷

¹Universidad de Valparaíso, Valparaíso, Chile. ²Center for Climate and Resilience Research (CR)2, Santiago, Chile. ³Universidad de Magallanes, Punta Arenas, Chile. ⁴Universidad de Santiago de Chile, Santiago, Chile. ⁵Universidad Nacional Andrés Bello, Viña del Mar, Chile. ⁶Universidad de Chile, Santiago, Chile. ⁷University of California, Los Angeles, USA

Abstract

Recent research has extensively analyzed summertime atmospheric river (AR) events in the Antarctic Peninsula (AP) using ground-based and atmospheric observations. However, a significant gap remains in understanding the occurrence and impacts of ARs during the Antarctic winter. This study focuses on an extraordinary warming event in the AP from 1 to 3 July 2023, utilizing data from in-situ winter observations and ERA5 reanalysis. On 2 July, the Frei station in the northern AP recorded an anomalous daily maximum near-surface air temperature of 2.7°C, significantly exceeding historical averages and indicating a substantial warming event. Radiosonde observations between 2 and 3 July showed a considerable rise in the freezing level to about 650 meters, contrasting sharply with the approximately 30 meters observed before the event. Concurrently, liquid precipitation was recorded, as corroborated by ERA5 data, leading to notable rain-on-snow and melt events. These events were captured in photographic evidence, marking the first observed instance of rainfall during the Antarctic winter. Synoptically, the event was characterized by a distinct trough over the Bellingshausen Sea and a pronounced northwest-southeast oriented blocking ridge from the southwestern Atlantic to the Weddell Sea. This configuration led to a dipole-like pressure pattern around the AP, fostering the development of a north-to-south oriented AR that transported warm, moisture-laden air from continental South America and the southeast Pacific towards the AP. Long-term winter trends indicate a strengthening of this pattern, resulting in increasingly pronounced northerly winds over the AP. Statistical analysis demonstrates a strong correlation between the strengthened dipole pattern and both increased AR frequency and warm temperature anomalies in the northern AP. This study highlights the critical need for more comprehensive in-situ winter observations as these are essential to fully capture the spectrum of AR impacts and to deepen our understanding of their influence in the region.

275

Antarctic seabirds as indicators of climate change: Science, Challenges and the Future

Prof. José Xavier^1,2, Prof. Richard Phillips², dr José Abreu^1,2, dr Lucas Bastos^1,3, Prof Charlotte Havermans^3,4, dr José Queirós^1,2, Prof. Akinori Takahashi⁵

¹University of Coimbra, MARE-UC, DCV, Coimbra, Portugal. ²British Antarctic Survey, Cambridge, United Kingdom. ³Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ⁴University of Bremen, Bremen, Germany. ⁵National Institute of Polar Research, Tokyo, Japan

Abstract

The Antarctic is arguably one of the regions that is most affected in the world by climate change. This presentation aims to: (1) review the effects of climate change on Antarctic seabird populations, (2) review recent advances in identification of prey (cephalopods and crustaceans) in the diet of Antarctic seabirds, and (3) discuss potential future consequences of climate change for Antarctic seabirds and strategies for their conservation related to the Antarctic Treaty. Climate change can affect Antarctic seabirds in various ways, not only through direct effects on the abundance, distribution and population dynamics of prey resources, but also because of concomitant changes in fishing activities, pollution, invasive species at breeding colonies and disease. For example, several Antarctic seabird species (grey-headed and black-browed albatrosses at South Georgia, king penguins at Crozet Islands) have shown shifts in diet, distribution or foraging behaviour in response to variation in the distribution and availability of prey in surrounding waters as a consequence of climate change. Guides for the identification of cephalopods and crustaceans from the Southern Ocean have been updated, and recent research shows the advantages of DNA-based methods for identifying cephalopods in predator diet, while providing new insights into their biology. In the future, the success of conservation policies for the Antarctic region will depend on more engagement between ecologists and policy makers to better account for the effects of climate change on Antarctic seabirds in relation to other threats, under a Antarctic Treaty context. Monitoring of the ecology and population status of seabirds is essential for understanding their roles in ecosystems, and adaptive management (e.g., regular monitoring of MPAs, flexible MPA boundaries) will be important for addressing future changes and ensuring the best outcomes for conservation.

280

Digital technologies in archeology and alternative ways of constructing stories about the Antarctic occupation (19th century)

Dr. Maria Jimena Cruz¹, Dr. Andrés Zarankin², Dr. Alex Martire³, Dr. Melisa A. Salerno¹

¹Multidisciplinary Institute of History and Human Sciences (IMHICIHU-CONICET), Buenos Aires, Argentina. ²Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil. ³Federal University of Rio Grande (FURG), Rio Grande, Brazil

Abstract

Since 2009, the Laboratory of Antarctic Studies in Human Sciences (LEACH) based at the Federal University of Minas Gerais (UFMG, Brazil) has conducted extensive research in Antarctic archaeology, notably through the "White Landscapes" project with the aim to understand human strategies involved in Antarctica's occupation. Unlike conventional narratives centered on "important men," this investigation sheds light on the often overlooked contributions of ordinary actors in the incorporation of this continent to the modern world.

Utilizing multidisciplinary approaches, the project delves into a diverse array of sources, ranging from material remains to written records. Through this comprehensive analysis, we challenge prevailing archaeological paradigms, presenting alternative narratives that reflect the complexity of Antarctic history.

In this presentation, we aim to discuss a new line of inquiry based on a digital approach to Public Archeology that is being developed in the project. This new path proposes the use and integration of digital technologies, such as video games, 3D scans and prints of artifacts, videos, visual records from drones, digital database and LEACH website as potential tools to engage with a wider audience and provide immersive experiences from a perspective based on the Digital Humanities. By leveraging these tools, we offer pluralistic perspectives that resonate beyond academic circles, fostering a more inclusive understanding of Antarctica's past.

By doing this, we aim to discuss how these efforts represent a paradigm shift in Antarctic archaeology, as we move away from linear narratives towards non-linear interpretations that capture the multifaceted nature of human experiences on the continent. Through the "White Landscapes" project, we aim to rewrite the conventional understanding of Antarctica's history, emphasizing the agency of diverse actors and challenging the dominant discourse. Ultimately, our research contributes to a more nuanced and inclusive portrayal of Antarctica's past, enriching our understanding of this unique and remote region.

285

Variability in Boundary Layer Stability Across Antarctica

Prof. John Cassano¹, Dr. Mckenzie Dice²

¹University of Colorado, Boulde, USA. ²University of Colorado, Boulder, USA

Abstract

Often the Antarctic boundary layer is described in terms of persistent, strong temperature inversions and strong static stability but some studies have highlighted the fact that weaker stability can occur frequently, even during the austral winter. Here, we analyze multiple years of radiosonde observations from three coastal (McMurdo, Syowa and Neumayer) and two continental interior (South Pole and Dome C) sites to characterize the range of boundary layer stability present on a seasonal basis across the Antarctic continent.

The artificial neural network data analysis technique known as self-organizing maps (SOMs) is used to objectively identify 30 boundary layer potential temperature profiles, at each site, that span the range of stability conditions observed. The results from this analysis reveal that strong stability dominates at the interior sites while coastal sites experience a wider range of stability conditions. This analysis also reveals that weaker stability near the surface is often capped by enhanced stability aloft, above the boundary layer.

Based on the SOM-identified potential temperature profiles thresholds of potential temperature gradient were selected to classify near surface stability ranging from near neutral to very strongly stable and stability aloft ranging from weakly stable to very strongly stable. These thresholds were then used to identify 20 stability regimes defined by both near surface and aloft stability. These thresholds were applied consistently to all five study sites allowing for a direct comparison of the frequency of different boundary layer stability regimes on a seasonal basis and across the continent. Finally, near surface wind speed and downwelling longwave radiation were compared across all of the stability regimes to identify wind and radiation conditions associated with varying stability. A comparison of the stability regime frequencies across the five study sites and the wind and radiation associated with each stability regime will be presented.

287

The role of education and outreach at the Antarctic Treaty Consultative Meetings: is science being used enough?

Prof. José Xavier^1,2, dr Dragomir Mateev³, Prof. Annick Wilmotte⁴, dr Andrea Aguirre⁵, dr Julie Jupe², dr Sonia Ramos-García⁶, dr José Abreu^1,2, dr Juan Alfonso⁷, Dr Renuka Badhe⁸, Dr Inga Beck⁹, dr Robert Bialik¹⁰, dr Andreia Carvalho¹¹, Dr Mihaela Cotta¹², Dr Anne Choquet¹³, Prof Silvia Dotta¹⁴, Dr Anna Fioretti¹⁵, Dr Lisolomzi Fikizolo¹⁶, Dr Johanna Grabow⁹, Dr Eoghan Griffin⁹, dr Hugo Guímaro^1,2, dr Patrícia Fialho¹⁷, dr Joana Fragão^1,2, Dr Louise Huffman¹⁸, dr Chaerin Jung¹⁹, dr Chandrika Nath⁹, Prof Burcu Ozsoy²⁰, Dr Jean de Pomereu²¹, Dr José Queirós^1,2, Dr José Seco^1,2, Dr Hyoung Shin¹⁹, dr Florica Toparceanu^12,22, Dr Ramcharan Vijayaraghavan²³, dr Marta Espirito-Santo^11,24, Dr Mike Sparrow²⁵, Dr Anoop Tiwari²⁶, dr Sophie Weeks²¹, Dr Kevin Hughes²

¹University of Coimbra, MARE-UC, DCV, Coimbra, Portugal. ²British Antarctic Survey, Cambridge, United Kingdom. ³Bulgarian Antarctic Institute, Sofia, Bulgaria. ⁴University of Liège, Liège, Belgium. ⁵Chilean Antarctic Institute, Punta Arenas, Chile. ⁶Comité Polar Español, Ministerio de Ciencia, Innovación y Universidades, Madrid, Spain. ⁷Centro de Oceanología y Estudios Antárticos, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela, Bolivarian Republic of. ⁸European Polar Board, Den Haag, Netherlands. ⁹Scientific Committee on Antarctic Research, Cambridge, United Kingdom. ¹⁰Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland. ¹¹Agrupamento de Escolas Professor Ruy Luís Gomes, Almada, Portugal. ¹²National Commission for Antarctic Research of the Romanian Academy, Bucharest, Romania. ¹³l'Institut Universitaire Européen de la Mer (IUEM), Université de Bretagne Occidentale, Brest, France. ¹⁴Universidade Federal do ABC, Santo André, São Paulo, Brazil. ¹⁵Istituto di Scienze Polari, Padova, Italy. ¹⁶Department of Forestry, Fisheries and the Environment, Cape Town, South Africa. ¹⁷European School of Varese, Varese, Italy. ¹⁸Ice Drilling Program, Dartmouth College, Hanover, USA. ¹⁹Korea Polar Research Institute, Incheon, Korea, Republic of. ²⁰TUBITAK Marmara Research Center, Istanbul Technical University, Istanbul, Turkey. ²¹Scott Polar Research Institute, University of Cambridge, Cambridge, United Kingdom. ²²Stefan S. Nicolau Institute of Virology, Romanian Academy, Bucharest, Romania. ²³Polar Educators International, ARCUS, Fairbanks, USA. ²⁴Instituto Superior de Lisboa e Vale do Tejo, ISCE, Lisbon, Portugal. ²⁵World Climate Research Division, Science and Innovation Department, World Meteorological Organization, Geneva, Switzerland. ²⁶National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Goa, India

Abstract

The Antarctic Treaty, signed in 1959, recognizes the Antarctic Treaty area as a region for peaceful purposes, promoting international scientific cooperation and environmental protection. Fostering education and outreach on the Antarctic region is important to inform stakeholders of the relevance of region, such as allowing scientific and educational awareness of this fragile environment, environmental stewardship, climate change education, historical/cultural significance, policy and advocacy, public engagement and inspire future generations while promoting international, interdisciplinary and collaborative research. In order to assess the relevance of education and outreach (E&O) activities about the Antarctic Treaty, recognized at the Antarctic Treaty Consultative Meetings (ATCM) and its Committee for Environmental Protection (CEP), we examine I) the amount of the number of ATCM papers submitted on E&O since 1961, II) the key topics and the target audiences detailed in papers submitted to the ATCM on E&O and III) potential challenges on E & O in the future at the ATCMs. Since the Antarctic Treaty was signed, a total of 216 ATCM papers on E&O have been produced. The number of papers has increased substantially since the mid-1990s. “Science” (76.9%) and “Wildlife/Biodiversity/Environment” (75.5%) were the most addressed topics in these papers, while “Public” (81.0%) and those attending “Schools” (69.0%) are the main target audiences. “Science” in ATCM papers increased c. 120-fold from 1961-1997 to 2015-2023, while ATCM papers discussing engagement with the “Public” increased c. 40-fold during the same period. “Climate change” was first mentioned in 2006 and the number of papers per year increased 4-fold by 2015-2023. This study shows increasing interest in E&O through time, addressing key topics to relevant audiences related to the Antarctic region. Emerging topics (e.g., Equity, Diversity and Inclusion) and the engagement of early career professionals and educators should be made a priority.

296

Earliest historical record of microplastics in Antarctica and influence of feeding mode on textile fiber intake by deep-sea benthic invertebrates

Dr. Gabriel Stefanelli Silva¹, Dr. Pâmela Friedemann¹, MSc. Beatriz Rocha de Moraes¹, Dr. Rômulo Ando¹, Dr. Lúcia Campos², Dr. Mônica Petti¹, Dr. Craig Smith³, Dr. Paulo Sumida¹

¹Universidade de São Paulo, São Paulo, Brazil. ²Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. ³University of Hawai’i at Mānoa, Honolulu, USA

Abstract

Studies on the extent of pollution, especially in remote areas, are crucial to conservation efforts. Following the advent of global plastic production in the mid-1900s, inefficient recycling and waste management policies have resulted in microplastics (<5 mm) being found in all studied oceanic environments. In this work, we provide information on the ingestion of textile fibers by benthic invertebrates sampled along the shelf of the Antarctic Peninsula, between 212 and 805 m depth. Studied organisms are deposited in biological collections spanning 30 years of research efforts, over the period of 1986 to 2016. A total of 85 fibers were found following analysis of 169 specimens. Seven fibers were identified as microplastics, with polymers encompassing polyamide, polycarbonate, polyester, polyethylene terephthalate, polysulfone, and synthetic rubber. We report the earliest documented record of microplastics in Antarctica, ingested by Boreomysis sp. mysids caught in 1986. Out of the 15 species studied, 13 had fibers within their gut content, or 31.36% of individuals. The highest fiber ingestion rates were recorded in the sea cucumbers Heterocucumis steineni (n=5) (100%), Molpadia violacea (n=6) (83.33%), and Scotoplanes globosa (n=4) (75%). The number of ingested fibers had a tendency to be higher in deposit and suspension feeders compared to predators, indicating a historical occurrence of textile debris in the sediment and water column of the world’s most remote continental margin. Our results renew concerns regarding human impact on this supposedly pristine environment. Lastly, we emphasize the importance of biological collections and archives, and the extensive efforts of curators and researchers in providing precious environmental insights even decades after sampling.

301

The forgotten nearshore: the complexities of protecting coastal marine ecosystems

Dr Oakes Holland^1,2, Dr Justine Shaw^1,2, Dr Jonathan Stark^3,4

¹Queensland University of Technology, Brisbane, Australia. ²Securing Antarctica's Environmental Future, Brisbane, Australia. ³Australian Antarctic Division, Kingston, Australia. ⁴Securing Antarctica's Environmental Future, Kingston, Australia

Abstract

Shallow coastal marine regions of Antarctica are very rare, small in size, and disconnected. At the same time, they are subject to terrestrial and marine threats and often coincide with human infrastructure. Despite this nexus of threatening processes, the ecosystems receive very little formal protection. Their smaller size makes them suitable candidates for protection under the Antarctic Specially Protected Area framework, however very few marine based ASPAs currently exist. Here, we explored the current state of nearshore protections and identify the complexities that arise when trying to designate ASPAs with marine components.

304

Penguins and particles: an important source of climate-relevant aerosol in Antarctica

Matthew Boyer¹, Lauriane Quéléver¹, Zoé Brasseur¹, Barry McManus², Scott Herndon², Mike Agnese², Dave Nelson², Rob Roscioli², Frederik Weis³, Sergej Sel³, Doug Worsnop², Aki Virkkula⁴, Eija Asmi⁴, Giselle Marincovich⁵, Francisco Quarin⁵, Mikko Sipilä¹

¹University of Helsinki, Helsinki, Finland. ²Aerodyne Research Inc., Billerica, USA. ³Palas GmbH, Karlsruhe, Germany. ⁴Finnish Meteorological Institute, Helsinki, Finland. ⁵Servicio Meteorológico Nacional, Buenos Aires, Argentina

Abstract

Aerosol particles influence the surface energy budget through cloud formation, and hence are relevant for climate. The sources of aerosol in Antarctica, however, are poorly constrained, which limits our ability to predict the climate response as the Antarctic environment warms.

In the remote Antarctic atmosphere, aerosol sources are limited. New particle formation (NPF) has a demonstrated role in Antarctic aerosol production (Jokinen et al., 2018; Quéléver et al., 2022). The gases involved in NPF, such as sulfuric acid, methanesulfonic acid, iodic acid, and ammonia, come from local ecosystem processes. However, direct observations of these gases are limited.

Herein, we present observations of NPF in the summertime Antarctic atmosphere from Marambio station, including the first highly sensitive online measurements of ammonia. Our measurements provide comprehensive characterization of NPF events, including the concentration of relevant gases, the chemistry of the growing clusters, and the size distribution of particles and ions > 1nm. We also measured cloud condensation nuclei (CCN) concentrations and cloud droplet number size distributions, which allows us to link NPF and growth with cloud formation processes.

We characterized the key sources of aerosol precursor vapors, especially ammonia. We found that penguin/bird colonies are significant source of ammonia, whereas the ocean is not. Our results also identify that the chemical mechanism of NPF is dominated by sulfuric acid and ammonia. We observe enhancement in particle formation rates with ammonia mixing ratios as low as 100 ppt. Using a specific case study, we are able to link regional NPF to enhanced CCN concentrations as well as subsequent fog/cloud formation.

Our results demonstrate the fundamental role of ecosystem processes in cloud formation over coastal Antarctica. Since the Antarctic environment is rapidly changing, and penguin populations may decline, this represents a potential feedback to cloud formation processes that affect the regional climate.

305

First focused geological sampling beneath the East Antarctic Ice Sheet

Dr. German Leitchenkov^1,2, Prof. Pavel Talalay^3,4, Dr. Ilnur Abdrachmanov¹, Dr. Nan Zhang³, Dr. Da Gong³, Mr. Yunchen Liu³, Dr. Yazhou Li⁴, Mr. Yuchen Sun⁵, Mr. Mstislav Vorob'ev⁶, Mr. Damir Khalimov⁷, Dr. Bing Li⁴, Dr. Vladimir Lipenkov⁷

¹Institute for Geology and Mineral Resources of the World Ocean, St.-Petersburg, Russian Federation. ²St.-Petersburg State University, St.-Petersburg, Russian Federation. ³Jilin University, Changchun, China. ⁴China University of Geosciences, Beijing, China. ⁵China University of Geosciences, Beijing, Christmas Island. ⁶Institute of Geography, Moscow, Russian Federation. ⁷Arctic and Antarctic Research Institute, St.-Petersburg, Russian Federation

Abstract

Targeted bedrock sampling was carried out on Princess Elizabeth Land (30 km south of the coast, at 69.585591S; 76.385165E) by drilling through a 545 m thick ice. The borehole was drilled using a new, modified version of the cable-suspended Ice and Bedrock Electromechanical Drill (IBED) designed by the Jilin University (China) and under a joint scientific project between VNIIOkeangeologia, Jilin University and China University of Geosciences (Beijing). The drill site is located on the axis of a high-amplitude linear magnetic anomaly that runs parallel to the coast for more than 500 km from Princess Elizabeth Land to Mac.Rosbertson Land. The nature of this anomaly remained unclear, but it is thought to be related to the suture zone between Proterozoic terrains formed during the Neoproterozoic amalgamation of the Rodinia supercontinent. Based on visual field identification, the 48 cm long core is presented by metamorphosed mafic rocks. The magnetic susceptibility of the sample is about 0.05 SI and this high value confirms that similar rocks produce a prominent magnetic anomaly. In the next Antarctic season, borehole geophysical logging will be conducted including temperature measurements for GHF calculations. In addition to new geological insights, several surprising results are being obtained that may change our view of the behavior of the East Antarctic Ice Sheet. First, the thickness of the basal ice is much thinner (0.17 m) than it was expected. Second, the basal ice is solidly frozen to the bedrock and measured temperature at the bottom of the borehole (-4.5°C) is far below pressure melting point, although numerical models predict melting at this site. This means that the base of the Antarctic ice may be colder than currently thought, and that ice flow and thermal models should be carefully reviewed.

306

Exploring the Unseen: developing a benthic monitoring program using ROVs in the West Antarctic Peninsula from the MS Roald Amundsen - A win-win for tourism and science

Manuel Novillo^1,2, Charlotte Kirchner³, Giulia Spadoni³, Christina Hess³, Andrew Lowther⁴, Elling Deehr Johannessen⁴, Federico Riet Sapriza⁵, Emily Baxter³, Tudor Morgan⁶, Verena Meraldi³

¹Instituto de Diversidad y Ecología Animal (IDEA-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ³HX | Hurtigruten Expeditions, London, United Kingdom. ⁴Norwegian Polar Institute, Tromso, Norway. ⁵Vida Silvestre, Montevideo, Uruguay. ⁶HX | Hurtigruten Expeditions, London, Switzerland

Abstract

Monitoring vulnerable marine ecosystems in the Antarctic is becoming increasingly difficult; rising costs associated with ship-based research programs, decreased research vessel availability and limited research funding are challenging the research community to develop new ways of providing important information to environmental managers. One avenue that has recently shown great promise is embedding scientific research into activities undertaken by the tourism industry. Expedition vessels operate with fixed itineraries, offering a unique opportunity to study remote, inaccessible regions, while also providing significant education and outreach opportunities to travelers.

A pilot project funded by the Hurtigruten Foundation in collaboration with HX | Hurtigruten Expeditions (HX) in the West Antarctic Peninsula (WAP), was conducted to evaluate using Remotely Operated Vehicles (ROV) to monitor candidate Antarctic notothenioid (icefish) spawning grounds. During two voyages on MS Roald Amundsen, 16 deployments of the Blueye Pioneer ROV were carried out from a zodiac to depths of 10 to 120m across several fjords and bays of the WAP as an operational and methodological trial. Eleven sites were surveyed resulting in ~9 hours of footage. Passengers were also invited to actively engage in the research by participating in ROV deployments, onboard lectures, and workshops, fostering a deeper understanding of rarely seen Antarctic ecosystems and their conservation importance.

Outcomes from the pilot study will be used to enhance and refine the development of a monitoring program for the spawning grounds of fish, historically overexploited taxa whose current status is unknown. Additional habitat suitability modelling efforts are underway to create a candidate list of sites for further survey effort. Ultimately the goal is to demonstrate to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), that through collaboration with the Antarctic tourist industry it is feasible to maintain a scientific monitoring program for a key group of krill-eating predators.

316

Historical sites and monuments as an interface for our understanding of history. An example of Russian heritage in Antarctica

Historical sites and monuments as an interface for our understanding of history. An example of Russian heritage in Antarctica Pavel Filin

Peter the Great Museum of Anthropology and Ethnography (the Kunstkamera) Russian Academy of Sciences, Saint-Petersburg, Russian Federation

Abstract

According to cognitive psychologist Donald Hoffman, who used a computer interface metaphor to describe our sensory perceptions of the world, cultural heritage objects can be envisioned as an interface for our understanding of historical events, similar to archive icons on a desktop. The Russian list of historical sites and monuments (HMS) includes eight sites, six of which were registered during the USSR era, and the last two in post-Soviet Russia. All the Soviet-era objects reflect the early years of the USSR's active involvement on the continent during the 1950s and 60s. The Pole of Inaccessibility station (HMS-4), now rarely visited, bears interesting significance. Apart from its inherent value, it also carries an ideological component – a bust of Lenin was placed on the building's roof. This object exemplifies a shift in perception over time. The ideological weight that was crucial for state ideology in the 1950s has diminished, yet it remains a significant symbol of Antarctica's historical phase. HMS 7 (Khmara' stone), 8 (Shcheglov's monument), and 9 (Cemetery on Buromsky Island) honor those who perished during Antarctica exploration. HMS 10 (Observatory of the Soviet Oasis station), is a relic from the mid-1950s, marking the initial stage of the USSR's work in East Antarctica. HMS 11 Heavy tractor and HMS 88 Professor Kudryashov's drilling complex at Vostok station; HMS 92 Heavy tractor "Harkovchanka represent technological achievements – all-terrain vehicles used for extensive crossings of the continent and a drilling rig yielding unique climatic data. These technics mirror distinct perceptual frames – while the former symbolize Soviet modernity and human triumph over nature, the latter reflects a "green agenda". A comprehensive analysis of the Russian objects' "file system" reveals their relation to peak moments linked to the USSR and Russia's exploration of Antarctica – including initial expeditions, human casualties, technological advancements, and the environmental focus.

319

Anthropological implications for Antarctic colonization from the geoarqchaeologial discoveries on the 'fat derived char concretion'

Dr Luís Assis

University od Federal District - UnDF, Brasília, Brazil

Abstract

In anthropology, the approach to object designs has driven debates about human adaptation to environments, cultural distinctiveness and distribution, and the nature of the technical function in establishing traditions. The 'fat derived char concretions', so-called the 'Antarctic Sealers Coal - ASC' stresses all of these themes.

Can the ASC be understood as a 'technical object' indicating human-environment modulations? If so, the ASC postulates doubts about the scope of past sealers' homeostasis and the impact its domestic process of making and use has on the capitalist exploration of the workforce and natural resources.

As long as concretions very similar to the ASC are to be found in other 'crio-landscapes' worldwide, what does ASC says, in terms of an antarctic human identity, or cultural differentiation process? Can the ASC be considered a material culture of a specific antarctic culture; or it is just a technique borrowed from the outside in the same capitalist icy venture? To annex the Antarctic to the World System, didn't the 'System' itself, produce the necessary 'culture of annexation' within the Antarctic (colonialities), not just from out there (colonialisms)?

Finally, if the classical Maussian proposal assumes techniques as the 'effective traditional act', how to understand tecnogenetic impacts on the environment, if not as a derived technical 'waste system'? To the extent that ASC (i) currently concentrates the same amount of carbon as ornithogenic soils and, yet, (ii) hosts natural-like keratinophilic soil activity - after just two human occupation events, one to three centuries ago -; maybe we found the Antarctic ancestral pollution nexus, very much corrspondant to the 'Great Acceleration'. Functional action, thought of in this way, displaces the classic interest in classificatory systems and social organization as a point of departure of a functional analysis, repositioning function in the ecology of performances. The unintended consequences of technical activities are 'Traditions'?

324

Unlocking Antarctica: Building an open access, accessible satellite data platform

Dr Alix Post, Kimberlee Baldry, Jonathan Mettes, Alex Bradley, Norman Mueller

Geoscience Australia, Canberra, Australia

Abstract

Satellite data over Antarctica provides a vast resource spanning decades for observing critical changes in the cryosphere, ecosystems and oceans. However, our ability to observe Antarctica systematically at a continental scale is constrained by difficulties accessing, storing and pre-processing satellite imagery prior to analysis. Factors such as cloud masking, reflectivity, prolonged periods of darkness, changes in atmospheric water vapour, aerosols and signal scattering mean that corrections applied to satellite data in other regions and in existing global products aren’t fully applicable to Antarctic conditions. To overcome these challenges, Geoscience Australia is developing Digital Earth Antarctica. This platform will improve access to corrected continental scale satellite data through use of Open Data Cube technology, providing open access to analysis ready time-series data that has been corrected and validated for Antarctic conditions. Optical data will initially include Landsat and Sentinel-2 collections, while Sentinel-1 will be pre-processed for access to synthetic aperture radar backscatter and interferometric data. Synthetic aperture radar (SAR) data over Antarctica overcomes the challenges of sustained observing during periods of cloudiness and darkness, and in Interferometric Wide swath mode can be used to detect changes in surface topography over time (InSAR).

This presentation will provide an overview of Digital Earth Antarctica’s planned processing pipelines to produce analysis ready optical and SAR data and the wealth of opportunities that will be unlocked to observe, monitor and understand Antarctic systems.

326

Extending the collaborative Fishing Vessel Ocean Observing Network (FVON) to vessels operating in Antarctic waters

Dr Peter McComb¹, Dr Christopher Cusack², Dr Patrick Gorringe³, Dr Naoki Hirose⁴, Dr Julie Jakoboski⁵, Dr Veronique Lago⁶, Dr Michela Martinelli⁷, Dr George Maynard⁸, Dr Hassan Moustahfid⁹, Carles Castro Muniain¹⁰, Dr A. Miguel Piecho-Santos¹¹, Prof Moninya Roughan⁶, Dr João de Souza¹², Cooper Van Vranken¹³

¹Oceanum, New Plymouth, New Zealand. ²Environmental Defense Fund,, San Francisco, USA. ³Swedish Meteorological and Hydrological Institute, Norrköping, Sweden. ⁴Kyushu University, Fukuoka, Japan. ⁵MetService, Raglan, New Zealand. ⁶University of New South Wales, Sydney, Australia. ⁷Institute of Marine Biological Resources and Biotechnology, National Research Council (CNR-IRBIM), Ancona, Italy. ⁸NOAA, Northeast Fisheries Science Center, Woods Hole, USA. ⁹US Integrated Ocean Observing System (US IOOS), Silver Spring, Maryland, USA. ¹⁰Ocean Data Network, Inc., Portland, USA. ¹¹IPMA-Portuguese Institute for the Sea and the Atmosphere, Lisbon, Portugal. ¹²Fondazione CMCC -Euro-Mediterranean Center on Climate Change, Lecce, Italy. ¹³Ocean Data Network, Inc, Portland, USA

Abstract

FVON is dedicated to facilitating cost-effective collection of surface and subsurface coastal and ocean observations, with focus on the pivotal role that fishing vessels can play to monitor essential ocean variables and enhance our understanding of the fundamental dynamical ocean processes. The network has gained recognition as an action ofthe United Nations Decade of Ocean Science, noting the critical significance of integrated multidisciplinary observations to support ocean-related monitoring and climate-informed management. FVON has applied for endorsement under the Global Ocean Observing System as an emerging observing network, and Australia’s Integrated Marine Observing System has created a Southern Hemisphere FVON data centre.

Existing observational platforms provide limited subsurface coverage, especially in shelf seas with depths below 1000m, and have limited cost-efficiency for scalable deployment. By exploring unique contributions for data collection from fishing (and other vessels) of opportunity, the role of FVON is to fill gaps and provide complementary datasets, particularly for variables like depth profiles of temperature and salinity.

Because FVON technologies and methodologies are maturing, barriers to entry have been significantly lowered for countries, industries and communities to establish their own Networks. This includes cost-effective high-quality sensors, FAIR/CARE data agreements, data-processing and standards aligned with international best practice, data science workflows, and distribution for third-party use (e.g. Global Telecommunication Service).

FVON’s objectives are to foster collaborative data collection and democratise global ocean observations. The presentation offers an Antarctic focus to the worldwide FVON initiatives (including a successful early Southern Ocean pilot), ongoing sensor development, the latest methodologies, data types, and some downstream use-cases. The goal is to encourage the science community about new opportunities for data collecting from fishing and other vessels of opportunity, as well as how to connect with the FVON team and gain access to their expertise.

336

Anthropic disturbance to the Antarctic permafrost: a case study of an airstrip construction

Dr Stefano Ponti, Prof Mauro Guglielmin

University of Insubria, Varese, Italy

Abstract

Recent climate change affects permafrost conditions worldwide in cold areas. In Continental Antarctica this trend is not clear although in the last years the active layer thickness (ALT) has increased with an almost stable air temperature trend. The remoteness of the environment and the Antarctic Treaty do not host a permanent population but the great scientific interest for this environment leads to an intense anthropogenic impact on the landscape in confined small areas around the scientific stations. It is for this reason that large engineering constructions rise scientific interest, especially in our study area located in Boulder Clay (Northern Victoria Land, Antarctica). Here, we want to highlight the effects of the construction of an airstrip on an ice-cored moraine till in cryotic conditions. In particular, we treat the effects on the ALT on: a) the surroundings of the airstrip, prior and post the construction and b) the modified surface layer of the airstrip compared to the original morainic deposit. We based our analyses on field data (thermistors), ground thermography and satellite images to gather a dataset of ground temperatures, snow cover distribution and thermo-physical properties of the ground surface. Linear regressions and ANOVA analyses showed that the airstrip produced negligible impacts on the surroundings both in terms of ALT and snow cover frequency. However, the reworked surface of the airstrip statistically demonstrated a different contribution of the surface energy balance components compared to the morainic till. As a result, the modified energy balance drives to an increase of ALT through the Stefan’s equation modelling. Therefore, if the current trend of climatic parameters is maintained, possible consequences are expected on the stability of the construction, especially due to the melting of the underlaying buried ice.

341

Quantifying Microplastic Concentration in Invertebrates from Three Antarctic Fjords

Ms. Natalie Simmons¹, Dr. David Barnes², Dr. James Scourse³, Dr. Justine Whitaker⁴, Ms. Tristyn Garza⁵, Dr. Alexis Janosik¹

¹University of West Florida, Pensacola, USA. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Exeter, Penryn, United Kingdom. ⁴Nicholls State University, Thibodaux, USA. ⁵University of Florida, Gainsville, USA

Abstract

Microplastics, small pieces of plastic measuring less than five millimeters, have spread to all ecosystems, even the Southern Ocean around Antarctica. In particular, microplastics have been found contaminating water in emerging fjords, inlets created by deglaciation, along the Antarctic Peninsula. Some of the fjordic sample sites are amongst the youngest marine environments in the Southern Ocean only having been exposed for years to decades by glacial retreat. Potential risks to organisms from microplastic exposure include issues with feeding, endocrine disruption, and exposure to adsorbed toxins, all of which can lead to lower fecundity and survivability. Antarctic communities are unique and dominated by invertebrates, such as polychaetes, sponges, ascidians, mollusks, crustaceans, and echinoderms. The objective of this study was to quantify microplastics in invertebrates from the Western Antarctic Peninsular fjords. Invertebrates were collected during 2017 and 2020 from three fjords via a mini Agassiz trawl to quantify microplastic concentrations and identify polymer composition using Micro-ATR-FTIR. The most common polymers were polypropylene, polycarbonate, polyamide, and polystyrene. Additionally, differences between microplastic concentration and feeding mechanisms were investigated. Microplastic presence was significantly higher in the invertebrate organisms sampled compared to controls (p < 0.001), but feeding mechanism was not found to be a predictor of microplastic bioaccumulation. Microplastics concentrations in invertebrates differed between fjords in 2017 (p = 0.010) but not in 2020. Complementing previous research on microplastics in fjordic water, this study reveals new evidence of microplastics in fjordic inhabitants.

346

Deconvoluting aerosol black carbon footprint in the Northern Antarctic Peninsula

Dr Newton de Magalhães

Rio de Janeiro State University, Rio de Janeiro, Brazil

Abstract

Black carbon is a short-lived aerosol that once deposited on snow and ice surfaces can accelerate melting by absorbing solar radiation. The negative effects of black carbon in accelerating glacier melting have been observed in various regions of the world: the European Alps, the Himalayas, the Andes Mountain range, and especially in the Arctic. For the Arctic, the International Maritime Organization (IMO) has been discussing how to reduce black carbon emissions from ships, and regulatory laws are under debate. Meanwhile, for the South Pole, limited discussions have been addressed about the impacts of black carbon on the Antarctic environment. A significant increase in black carbon flux has been observed in the Antarctic Peninsula over the years. Previous studies attributed sources and impacts of rBC in the northern Antarctic Peninsula (nAP) region by investigating long-range atmospheric transport from South Hemisphere biomass burning, or by assessing impacts from local tourism and research activities. Here we used very high-resolution measurements of refractory black carbon (rBC) in a firn core collected near the northern tip of the Antarctic Peninsula, as well as satellite measurements, modeling, burned area data and tourism statistics, to assess the combined impacts of both long-range transported rBC and locally emitted rBC from maritime tourism during the period 2003 to 2008. Our findings suggest that during spring and winter, rBC concentrations primarily reflected South American and South African burning, respectively, while summer rBC concentrations were related primarily to maritime tourism. Model results for the summer of 2007/2008 corresponding to the first boom in Antarctic tourism suggest a 0.4% albedo reduction which potentially resulted in enhanced ice melt of up to 206 g m^-2 day^-1. Our findings emphasize the urgency of assessing rBC and other emissions from shipborne tourism in the Antarctic Peninsula region and their effects on the environment such as enhanced ice melt.

348

Trophic Coupling and Zooplankton Distribution Dynamics Across the Water Column: Insights from a 20-Hour Experiment in the Bransfield Strait, Northern Antarctic Peninsula

MSc Letícia Baldoni¹, BSc Raul Costa¹, PhD Vanessa Agostini², PhD Carlos Mendes¹, PhD Erik Muxagata¹

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Regenera Moléculas do Mar, Porto Alegre, Brazil

Abstract

The Bransfield Strait is significantly influenced by water masses from surrounding regions, making it essential for understanding the impacts of climate change. The rapid warming and sea-ice decline reported in recent decades affected marine ecosystems and trophic levels, particularly evident in shifts in phytoplankton composition and zooplankton abundance. Understanding meso- and macrozooplankton distribution and composition in this area is vital for elucidating their role in carbon export and interactions with phytoplankton, explaining local-scale responses to oceanographic dynamics and trophic interactions. This study analyzes meso- and macrozooplankton composition and vertical distribution alongside phytoplankton communities during a 20-hour observation period in February 2017 at a fixed station in the central basin of the Bransfield Strait. Additionally, it evaluates krill and salp feeding behavior through the composition of phytoplankton pigments in their fecal pellets. Water temperature and salinity data revealed variations in the upper 100 meters, with two distinct adjacent water masses identified. Small cryptophytes dominated the phytoplankton community. At the same time, meso- and macro-zooplankton were mainly comprised of salps and copepods, with Salpa thompsoni and Metridia gerlachei being the most abundant species, respectively. Diel vertical distribution of zooplankton showed higher copepod abundances in deeper layers (100-500 m) and salps prevalent near the surface (0-100 m). Community composition varied significantly with depth, including an ontogenetic migration in calanoid copepods during the nocturnal period, when the abundance of S. thompsoni decreased at the surface, indicating a reverse migration behavior. Zooplankton fecal pellets from krill and salp experiments suggested grazing activity, highlighting the selective feeding behavior of krill. These findings highlight the potential implications of differences in salps abundance at different depths for zooplankton community structure and the local ecosystem in the Bransfield Strait region.

350

Prevention, control and management of H5N1 avian influenza in Antarctica: its regulation under the Antarctic Treaty System and comparative domestic law

Dr. Luis Valentín Ferrada^1,2, Giovannina Sutherland^1,2, Catalina Sepúlveda^1,2, María Jesús Maibe^1,2

¹Millennium Institute BASE, Santiago, Chile. ²Universidad de Chile, Santiago, Chile

Abstract

Highly pathogenic avian influenza H5N1 (HPAI) is an extremely contagious viral disease with high levels of mortality in birds and marine mammals, which can be transmitted through contact with respiratory secretions or feces. Recently, on February 24, 2024, two infected skuas were found near the Antarctic base "Primavera".

This is a biosecurity emergency that puts the entire Antarctic environment in danger and requires a unified response by the States, being a practical manifestation of the challenges faced by the Antarctic Treaty System to achieve joint regulation.

During the XLV ATCM (Helsinki, 2023) and especially in the report presented by the Committee for the Protection of the Environment (CEP), the potential risks of HPAI proliferation in Antarctica and its effects were warned, advising the Parties to share national experiences and promote preventive procedures through each program. However, no applicable measures were adopted in this area and suggestions for protocols came from organizations participating in an advisory capacity.

Although some countries have made progress in these matters as reported in the XLV ATCM (United States, WP 3/2023; Chile, IP 122/2023; South Korea, IP 23 rev.1 /2023; United Kingdom, IP 30/2023; IAATO, IP 52/2023; and SCAR/IAATO/COMNAP, IP 101/2023), they advance independently in the determination of restrictions. Thus, to date, a series of domestic regulations have been generated that deal with the prevention, control and management of HPAI in the Sixth Continent, which from different objectives and interpretations are in charge of a transversal matter such as the protection of the Antarctic environment. What should be the best mechanism to regulate? Could the multiplicity of biosecurity protocols imply any risk in the manage of this contingency? Our objective is to answer these questions from the comparison of domestic law of different countries, among them, Chile.

359

Biodiversity informatics for Antarctic environmental conservation

Professor Steven Chown¹, Professor Melodie McGeoch¹, Dr Rachel Leihy^1,2

¹Monash University, Melbourne, Australia. ²Arthur Rylah Institute, Melbourne, Australia

Abstract

Antarctica is the only continent set aside as a natural reserve devoted to peace and science, with environmental protection mandated through the Protocol on Environmental Protection to the Antarctic Treaty. The continent's surrounding sub-Antarctic islands enjoy similarly high levels of protection, as does the Southern Ocean under the Convention on the Conservation of Antarctic Marine Living Resources, though with rational use being included in the definition of conservation. The extent to which these legal protections succeed depends on high-quality biodiversity knowledge, for status and trends of indigenous species, and for the same information with respect to Invasive Alien Species (IAS), along with understanding of the pressures on the region. Yet such information is remarkably fragmentary, and its route into the policy environment less than straightforward. In consequence, whether that best available data, information, and knowledge are accessible to decision-makers, practitioners, and the public for the region is not certain. In this presentation, current progress in resolving these challenges is laid out, including the way in which progress in the Antarctic region may inform and be informed by developments elsewhere. We use Invasive Alien Species (or Non-Native Species in Protocol Language) biodiversity informatics data as a specific example, illustrating the success of policies reflected in these data.

361

On a Rock and in a Hard Place: Women, Science and Extreme Environments

Ms Vandana Singh

Victoria University of Wellington, Wellington, New Zealand

Abstract

Autobiographies and biographies have contributed enormously to the feminist history of science, making women scientists visible, and helping to mainstream their voices. They provide useful insights into the lives, times, experiences, struggles and achievements of the scientists and bring their stories to the forefront. But while many accounts and biographies, especially of ‘explorers’, aimed at popular readership, and often to fund further explorations, highlight the drama in scientific field work in remote places – the daring, the courage, the stoicism and valour in the face of unmitigated physical hardship – science is often prodding everyday work when what you wear, what gear you carry, how well your helmet fits, how easy it is to urinate, how to cope with (or how to control) your periods plays an important role in how efficiently you are able to do your research. These issues can also sometimes literally make a difference between life and death. I am writing a biography of women scientists working in remote, extreme and physically challenging locations, including Antarctica, that will hone into their lived experience. I aim to capture the minutiae of everydays of women scientists – the grandiose as well as the drab elements that determine how enriching your work is, how much you want to come to work and continue to work in the field, and how fulfilled and satisfied you feel with your work when you look back to the day, the week, the month, the year gone by. In this paper, based on my PhD in progress, I use biographical writings, oral histories and interviews to explore the experiences of women scientists working in Antarctica and to make connections with the experiences of women scientists working in other remote, extreme and physically challenging places such as high seas and deep sea (particularly the Southern Ocean), outer space, caves (and mines), forests, tree canopies, and glaciers.

363

Consequences of extended ozone depletion and reduced snow and ice cover for Antarctic biota

Professor Sharon Robinson^1,2, Dr Laura Revell³, Dr Roy Mackenzie^4,5, Dr Rachele Ossola⁶

¹Securing Antarctica’s Environmental Future, University of Wollongong, Wollongong, Australia. ²School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ³School of Physical and Chemical Sciences, University of Canterbury, Canterbury, New Zealand. ⁴Cape Horn International Center CHIC, Universidad de Magallanes, Puerto Williams, Chile. ⁵Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems BASE, Santiago, Chile. ⁶Department of Chemistry, Colorado State University, Fort Collins, USA

Abstract

Stratospheric ozone is critical for shielding the biosphere against ultraviolet-B (UV-B) radiation and has been damaged in recent decades by the release of anthropogenic gases. The ozone layer is expected to recover before the end of the 21st century, however a hole continues to appear over Antarctica each year. Ozone depletion usually peaks between September and October, when fortunately, most Antarctic terrestrial vegetation and soil biota is frozen, dormant, and protected under snow cover. Similarly, much marine life is protected by sea ice cover. This means that if ozone depletion primarily occurs in early Spring, most biota will be protected from the increased UV-B radiation. However, in recent years, ozone depletion has persisted into the austral summer. Early summertime ozone depletion is concerning since high incident UV-B radiation coincident with snowmelt and emergence of vegetation will mean more exposure for biota. The start of summer is also peak breeding season for many animal species, thus extreme UV-B radiation (UV index up to 14) may come at a vulnerable time in their life cycle. Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV-B exposure of Antarctic biota, through earlier ice and snowmelt. These combined stressors could result in regime shifts in marine and terrestrial environments. Antarctic field research conducted decades ago tended to study UV impacts in isolation and more research, that considers combined climate impacts and the true magnitude and timing of current UV exposure, is needed.

366

CCAMLR’s progress toward a network of Southern Ocean Marine Protected Areas

Dr. Cassandra Brooks

University of Colorado Boulder, Boulder, USA

Abstract

Marine protected areas (MPAs) are an increasingly popular management tool for conserving biodiversity. In line with global targets, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has been working towards adopting a network of Southern Ocean MPAs for more than 20 years. Extensive science, outreach, and diplomacy has underpinned these efforts, and the process has at times moved slowly given that CCAMLR makes all decisions based on consensus. In 2009, CCAMLR adopted its first MPA south of the South Orkney Islands. Then in 2016, CCAMLR adopted the world’s largest MPA in the Ross Sea, Antarctica. Four additional MPAs remain under negotiation in the East Antarctic, western Antarctic Peninsula, western Weddell Sea and eastern Weddell Sea region. Some of these proposals have been under negotiation for more than 10 years, however, CCAMLR has not been able to achieve consensus on any new MPAs since 2016 due to a myriad of complex issues. These include: difficulties negotiating during the Covid-19 pandemic; ongoing geopolitical tensions, especially due to the ongoing war in Ukraine; and conflicting economic interests. Despite these difficulties, the majority of CCAMLR Member States have demonstrated a commitment to moving forward on a network of Southern Ocean MPAs. These Members have continued to engage in scientific and diplomatic efforts related to Southern Ocean MPAs, and MPA proposals have had an increasing number of Member State proponents over time. Further, CCAMLR’s two existing MPAs have been actively managed, including through research and monitoring by many Member States. This talk will close by sharing some of the ongoing research and monitoring efforts in the Ross Sea region MPA, including moving towards building a collaborative international research community. These efforts demonstrate that Southern Ocean MPAs can be both highly protected and well-managed, providing a potential framework for other international ocean areas.

367

Polar Atmosphere Lidar Observation System at Zhongshan Station, Antarctica

Wentao Huang¹, Rui Wang¹, Xiangcai Chen¹, Chao Ban², Fuchao Liu³, Weilin Pan², Zhangjun Wang⁴, Hongqiao Hu¹, Huigen Yang¹

¹Polar Research Institute of China, Shanghai, China. ²Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China. ³Wuhan University, Wuhan, China. ⁴Institute of Oceanographic Instrumentation, Shandong Academy of Sciences, Qingdao, China

Abstract

The polar regions are key parts of the global general circulation of Earth’s atmosphere with unique phenomenon and processes, and the main entrances for the energy and particles of solar wind entering geospace. Chinese Zhongshan Station (69°22’24”S, 76°22’40”E) in Antarctica locates near the shore of the continent and at the unique cusp latitude. Considering as an ideal place for polar atmopshere observation and research, the Polar Research Institute of China developed and deployed a Polar Atmosphere Lidar Observation System (PALOS) at Zhongshan Station, which is a synthetic lidar observation system covering all layers of neutral atmosphere and the first of its kind in Antarctica.

In PALOS, a Sodium (Na) resonance fluorescence Doppler lidar is established in 2019 to observe the Mesosphere and lower Thermosphere, which is capable of measuring the horizontal winds, temperature and Na number density around 75-110 km for both day and night. A pure rotation Raman lidar, a Rayleigh/Mie scattering lidar module and a coherent Doppler wind lidar are installed in 2020, which measure troposphere-stratosphere-mesosphere temperature and boundary layer wind. The deployment and the operation of PALOS are mostly supported by Chinese National Antarctic Research Expedition (CHINARE), and thousands of hours of observation data have already been accumulated, which can be used to investigate the basic characteristics of the polar atmosphere, the thermal/dynamic processes in middle and upper atmosphere, etc. With coordinated observation, silmutaneously observed temprature profiles can cover most part of the neutral atmosphere. In mesopause region, active sporadic and thermospheric Na layers associated with the activites of sporadic E layers (Es) and aurora have been observed. Continouse horizontal winds and temperature data covering mutiple days also reveals strong atmospheric wave activities above Zhongshan Station.

370

Bedmap3: a project synopsis and look at future outputs.

Dr Peter Fretwell, Dr Hamish Pritchard, Dr Alice Fremand, Dr James Kirkham

British Antarctic Survey, Cambridge, United Kingdom

Abstract

We present a synopsis of recent Bedmap3 outputs and discuss current and future initiatives linked to the SCAR Bedmap3 project. These include, firstly, publication of the Bedmap3 dataset; 80+ million geospatial data points of bed elevation and associated information collected by the Antarctic geophysical community over the last 60 years and made accessible using the FAIR data principles. These data are available through the new SCAR Bedmap3 data portal (https://bedmap.scar.org/) and include standardized information from 270+ surveys from 50+ international partners associated with the Bedmap3 project.

Secondly, we present the Bedmap3 gridded products describing the surface elevation, ice-thickness and the seafloor and subglacial bed elevation of Antarctica south of 60° S. Bedmap3 incorporates and adds to all of the post-1950s datasets previously used for Bedmap1 and Bedmap2, including 84 new aerogeophysical surveys by 15 data providers that represent an additional 52 million data points and 1.9 million line kilometres of measurement. These latest data have filled major gaps particularly in East Antarctica, including the South Pole and Pensacola basin, Dronning Maud Land, Recovery Glacier and Dome Fuji, Princess Elizabeth Land, plus the Antarctic Peninsula, West Antarctic coastlines, and the Transantarctic Mountains. Our newly defined Bedmap3 grounding line product similarly consolidates multiple recent mappings of this spatially varying boundary.

Finally, we introduce two ongoing Bedmap3 initiatives; Bedmap3 ice flow drainage and subglacial hydrology mapping, using the new gridded products to investigate catchments and reverse slopes, and the Bedmap3 Map, a new double sided map showcasing the Bedmap3 project.

372

Evolution of Rock Glaciers in Jhelum basin, J&K, India

Mr ZAHID MAJEED

Geological Survey of India, Srinagar, India

Abstract

The Kashmir Himalayas are witnessing glacier shrinkage and melting, especially evident in the Pir Panjal Mountain Range (PPMR). Field observations reveal well-preserved remnant glacial landforms of past glaciation, characterized by distinct features such as paired lateral moraines, proglacial lakes, wide U-shaped valleys, glacial polishing, and striated pavements etc. Notably, the emergence of rock glaciers stands out as a significant indicator of shrinking glaciers in this region mostly of glaciogenic in nature. Rock glaciers, consisting of a mix of angular rock debris and ice, exhibit lobate or tongue-like formations and are commonly found in high mountain environments. Through field investigations and high-resolution satellite data analysis, over 200 rock glaciers covering approximately 51 km2 have been identified. These landforms are mapped from 3700 masl to 4550 masl, with surface slopes ranging from 11° to 27°, predominantly located on the northern face of the PPMR. Their dynamic nature, attributed to ice flow deforming the rock debris, is evident from distinctive surface topography resembling lava flow patterns. Permafrost features such as patterned ground and gelifluction lobes, observed mainly above 4000 meters observed during fieldwork, further indicate the presence of permafrost in the region. The study suggests that most rock glaciers have evolved from receding glaciers of the Jhelum Basin confined to cirques and smaller glaciers transitioning into rock glaciers. Understanding the spatial distribution and characteristics of rock glaciers, along with their hydrological significance, is crucial for assessing long-term water availability in the basin. The observed climatic trends, marked by increasing temperatures likely contribute to glacier recession, increasing debris cover and the formation of rock glaciers through enhanced ablation and reduced snow accumulation. As climate-driven glacier recession persists, the transition may change more glaciers into rock glaciers and significance of rock glaciers is expected to escalate, underscoring the need for continued investigation and monitoring.

374

Modelling the Patagonian Ice Sheet and its palaeoclimatic controls through the last glacial cycle

Ms María-Paz Lira¹, Dr Stewart Jamieson¹, Dr Michael Bentley¹, Dr Juan-Luis García², Dr Robert McCulloch^3,4

¹Durham University, Durham, United Kingdom. ²Pontificia Universidad Católica de Chile, Santiago, Chile. ³University of Edinburgh, Edinburgh, United Kingdom. ⁴Centro de Investigación en Ecosistemas de la Patagonia, Coyhaique, Chile

Abstract

Geochronology records from the former Patagonian Ice Sheet (PIS) show an asynchrony between different outlets for the maximum ice extents through the last glacial cycle. In general terms, the ice maxima in northern and southern Patagonia occurred during MIS3 but in central Patagonia, most of the geochronology indicates ice maxima during MIS2, contemporaneous with the global Last Glacial Maximum. Reasons for this asynchrony are unclear, but it is most likely related to changes in climatic factors, such as the shifting of the Southern Westerly Winds (SWW) and associated precipitation in response to Antarctic sea-ice expansion. There is agreement that the SWW have a northward displacement during cold periods but the movement pattern is not clearly known, as some refer to a migration of the SWW core, while others believe that the core expands northwards. Understanding the past climatic conditions would provide insight into the timing of PIS growth and decay.

Here,we report the results of modelling the ice sheet, using PISM, through the last glacial cycle. We created a set of palaeoprecipitation scenarios based on proxy data evidence, and we use the model to test the PIS response to these scenarios. We produce an ice sheet model that fits well with evidence for the past ice extent at the Local LGM and during deglaciation. From our simulations, we suggest that the core of the SWW had an expanded configuration and that the northern position of the SWW core fluctuated through the last glacial cycle. These past precipitation configurations played an important role in the asynchrony of the PIS during the last glacial cycle. However, topographic differences such as in ice surface elevation in the northern, central and southern PIS are also crucial in the evolution of mass balance change and local glacier response.

375

The Elephant in the Room? An Analysis of the carbon footprint of tourism activities in Antarctica

Dr. Daniela Cajiao¹, Dr. Johnny Aase^2,3, Dr. Javier Benayas⁴, Dr. Machiel Lamers¹, Ph.D student Anisja Obermann¹, Dr. Pablo Tejedo⁴, Dr. Marisol Vereda⁵, Dr. Bas Amelung⁶

¹Environmental Policy Group, Wageningen University and Research, Wageningen, Netherlands. ²University of Tasmania, Hobart, Australia. ³Norwegian Defence University College, Oslo, Norway. ⁴Universidad Autonoma de Madrid, Madrid, Spain. ⁵Universidad Nacional Tierra del Fuego, Ushuaia, Argentina. ⁶Earth Systems and Global Change Group, Wageningen University and Research, Wageningen, Netherlands

Abstract

Cruise and aircraft operations constitute the main transportation modes to access Antarctica and both are known to be very carbon-intensive. The first evidence of Antarctic tourism’s carbon footprint was provided by Amelung & Lamers (2007), Farreny et al. (2011), and later Li et al. (2022). These calculations prompted the debate about the allegedly positive contribution of Antarctic tourism in the creation of ‘Antarctic ambassadors’ and the role of tourism in the conservation of the continent (Vila et al., 2016). Since the first carbon calculations, the number of tourists has more than tripled, itineraries have expanded further South, and modalities and activities have diversified (IAATO, 2023). During this time tour operators have also implemented more efficient and sustainable operations, for example through the introduction of new and more fuel-efficient vessels.

We aim to present an up-to-date estimate and discussion of the carbon footprint of Antarctic tourism in the context of Environmental Stewardship while also introducing a more comprehensive method for calculating emissions produced by tourism operations. Our calculations consider two operational components: 1. during the Antarctic journey, corresponding to the cruising stage in Antarctica, and 2. beyond the Antarctic journey concerning the travel to arrive at the gateway city of departure. We include all Antarctic gateway cities and the main tourism modalities (i.e., cruise only, cruise with landings, and air-cruise).

We expect our findings (work in progress) could inform discussions and decision-making, including the significance of managing growth and diversification, the relevance of environmental impact assessment, and the appropriateness of promoting the ambassador concept. From a methodological perspective, we expect our methodology could enable further carbon calculations at other destinations. Our results will also contribute to the broad debate concerning the significance of tourism's carbon footprint under a climate emergency period, the role of self-regulation, and Environmental Stewardship in the Antarctic.

376

Marine productivity changes in the Ross Sea Polynya (Antarctica) during the last 500 years as inferred from diatom assemblages

Lorena Rebolledo¹, So-Young Kim², Bárbara Montecinos³, Práxedes Muñoz⁴, Jeong-Hoon Kim²

¹Chilean Antarctic Institute (INACH), Punta Arenas, Chile. ²Korea Polar Research Institute (KORI), Incheon, Korea, Republic of. ³Universidad de Magallanes, Punta Arenas, Chile. ⁴Universidad Católica del Norte, Coquimbo, Chile

Abstract

The Ross Sea polynya is one of the most productive regions of the Southern Ocean sustaining a rich marine fauna. We analyzed total amounts of diatoms, opal, organic carbon, nitrogen and magnetic susceptibility in two cores recovered in 2021 from the Ross Sea during RV ARAON Expedition ANA11, in order to investigate past variations of marine primary productivity in the Ross Sea polynya. Two short cores – core 54 (length: 35 cm) located in the northern part of the polynya and core 59 (length: 45 cm) located at a coastal site – show sedimentation rates ranging between 0.07 and 0.08 cm yr^-1, estimated by the ²¹⁰Pb dating technique. Core 54 showed a good preservation of diatoms than Core 59, which was characterized by higher amounts of diatom remains below 20–35 cm with high values of magnetic susceptibility. Core 59 may infer more terrigenous inputs and fragmentation by erosion. We reconstructed sea-ice condition based on the ratios of Eucampia antarctica (terminal versus intercalary valves), Fragilariopsis curta/F. cylindrus, F. kerguelensis, where high values of these ratios are known to indicate stronger marine sea-ice condition. We speculate that core 54 was influenced by stronger sea-ice condition between 1600–1850 AD, possibly related to the Little Ice Age (LIA) – a regionally colder period followed by abrupt modern-era warming since 1850 AD. The observed higher diatom productivity during the cold LIA periods is the likelihood of more efficient polynya condition favoring diatom growth, tentatively associated with intensified katabatic winds and Amundsen Sea low (ASL). Comprehending such linkages requires further in-depth interpretations of physical-biological coupling processes in the Ross Sea polynya environments, as well as sufficient age control.

377

Wild Wild South Shetlands: The Case of King George Island, a new tourism hub?

Dr. Daniela Cajiao¹, Dr. Andrey Todorov², Dr. Erik Molenaar², Dr. Machiel Lamers¹

¹Environmental Policy Group, Wageningen University and Research, Wageningen, Netherlands. ²Netherlands Institute for the Law of the Sea, Utrecht University, Utrecht, Netherlands

Abstract

Human uses in Antarctica are intensifying and diversifying. Around 10000 scientists and 117.000 tourists visited Antarctica during the season 2023-2024 (IAATO, 2023, BAS 2024). Research and tourism are concentrated in the South Shetlands islands where most facilities are located (ATS, 2024). Both operations are strongly intertwined, frequently relying on the same infrastructure and facilities. King George Island (KGI) has become an important hub for fly & cruise operations, as the airstrip ‘Teniente R. Marsh’ facilitates access for tourists and researchers to Antarctica. Approximately 85% of the total passengers are tourists while the remaining 15% correspond to researchers and logistical staff (pers. comm. Chilean Civil Aviation, 2024). As operations on KGI grow, there will be a need for more logistical support and infrastructure, while entailing an increasing human pressure on the surrounding land and marine areas. From a legal perspective, due to the unresolved question of territorial sovereignty in Antarctica, there is considerable uncertainty on which States may or should exercise jurisdiction over their research stations and infrastructure as well as the legal basis for such jurisdiction. This presentation explores the complexity of balancing conservation, socio-economic and other rights, interests, and obligations of stakeholders operating in KGI, under the unique international law setting in Antarctica. During the 2023-2024 season, we conducted participant observation and interviews with key stakeholders on KGI to understand the interrelationships of state and non-state operators, the issue of activities’ diversification, and the shared use of facilities. We expect that this analysis could spark a broader debate among the scientific community, managers, and policy-makers concerning how best to respond to the fly & cruise developments on KGI and elsewhere from a regulatory perspective, as this could represent a significant shift in the way tourism and research are being conducted in Antarctica.

385

Understanding the interrelationship of environmental biogeochemistry and microbial community dynamics in the intertidal geothermal ecosystems of Deception Island, Antarctica

Dr. Aparna Banerjee^1,2, Dr. Alexis Castillo², Dr. Alexander Galán², Dr. Paris Lavin^3,4, Dr. Alex Echeverría², Prof. Rajesh Sani⁵, Dr. André Antunes⁶, Prof. Victor Parro⁷, Prof. Gustavo Cabrera⁸

¹Instituto de Ciencias Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Talca, Chile. ²Centro de Investigación de Estudios Avanzados del Maule, Vicerrectoría de Investigación Y Postgrado, Universidad Católica del Maule, Talca, Chile. ³Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile. ⁴Centro de Investigación en Inmunología y Biotecnología Biomédica de Antofagasta, (CIIBBA), Universidad de Antofagasta, Antofagasta, Chile. ⁵Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology,, Rapid City, USA. ⁶State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Taipa-Macau SAR, China. ⁷Centro de Astrobiología (CSIC-INTA), Madrid, Spain. ⁸Universidad San Sebastián Campus Las Tres Pascualas, Facultad de Ciencias Para el Cuidado de la Salud, Concepción, Chile

Abstract

Deception Island is an active volcano in Bransfield Strait, north to Antarctic Peninsula. It is one of the two active volcanoes in Antarctica where a history of eruptions are observed. The restless caldera is a volcanic complex with several geothermally heated grounds and fumaroles in intertidal zone. Polyextremophilic ecosystem of Deception Island is unique, harbouring high bacterial diversity compared to other similar ecosystems on planet Earth, rendering huge biotic potential. The polyextreme conditions of the geothermally heated ecosystems here survive hypersalinity, extreme pH, high temperature during temperature extreme, UV irradiation, and several metal enrichments, offering a broad range of adaptations to the bacteria ensuing production of bioactive secondary metabolites, including polysaccharides. The geochemistry and environmental spatial variability indicate Whaler´s Bay to be rich in nutrients like phosphate and nitrate, while Pendulum Cove has relatively anoxic environment with the presence of nitrite, silicate, and greenhouse gas N₂O. Greenhouse gases CH₄ and CO₂ are also recorded high in Crater 70 and Obsidiana, respectively. The profiling of major and minor elements indicated element enrichment in geothermally heated grounds and fumaroles. The microbial community dynamics profiling shows a clear separation into three groups, where geographically separated Irizar Lake-Fumarole Bay and Kroner Lake-Whaler´s Bay share somewhat similar microbial communities. While the study sites having temperatures>50°C have higher phylum abundance of Cyanobacteria, the higher the temperature, the more archaeal communities are present. For survival against extreme factors, the water and sediments from the geothermally heated study sites also indicate the presence of biofilm matrix. In conclusion, the interrelationship of environmental biogeochemistry and microbial community in Deception Island intertidal geothermal ecosystems is unique, rendering several bioactive compound production possibilities. The unique site also calls for a microbial conservation approach in an era of climate change. We are thankful to INACH RT_24-21 for funding.

387

Observing blue ice areas using remote sensing, deep learning, and field-based methods

Veronica Tollenaar^1,2, Harry Zekollari^2,3,4,1, Raul R. Cordero⁵, Fernanda Cabello⁵, José Jorquera⁵, Devis Tuia⁶, Marc Rußwurm⁷, Benjamin Kellenberger⁸, Stef Lhermitte^9,10, Maaike Izeboud¹⁰, Frank Pattyn¹

¹Laboratoire de Glaciologie, Université libre de Bruxelles, Brussels, Belgium. ²Department of Water and Climate, Vrije Universiteit Brussel, Brussels, Belgium. ³Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Zurich, Switzerland. ⁴Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland. ⁵Universidad de Santiago de Chile, Av. Bernardo O’Higgins, Santiago, Chile. ⁶Environmental Computational Science and Earth Observation Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Sion, Switzerland. ⁷Laboratory of Geo-information Science and Remote Sensing, Wageningen University, Wageningen, Netherlands. ⁸Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA. ⁹Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium. ¹⁰Department of Geosciences & Remote Sensing, Delft University of Technology, Delft, Netherlands

Abstract

Whereas most of Antarctica is covered by snow, ~1% of its surface exposes blue ice. These blue ice areas are of scientific interest, as they can harbor meteorite concentrations and old ice. However, blue ice areas also enhance mass loss at the surface (e.g., surface melt) through their low albedo compared to surrounding snow. Therefore, it is important to locate blue ice areas and monitor their evolution in a warming climate.

Here, we present a new blue ice area map based on multi-sensor and multi-temporal satellite observations. To generate the map, diverse satellite data, including images and products from MODIS, RADARSAT-2, and TanDEM-X are combined using deep learning. To this end, we rely on a property of neural networks: in the absence of perfect labels, neural networks can learn underlying patterns of so-called ‘noisy’ labels before adapting to the particular errors of individual scenes during later training epochs. The new blue ice area map of Antarctica shows that blue ice covers ca. 140,000 km², of which ca. 50% is located within 20 km of the grounding line.

In the grounding zone, it is essential to understand the interaction between solar radiation, blue ice, and the surface mass balance (e.g., melt) to determine the future stability of the ice sheet. Some of these measurements can be obtained through remote sensing, but there is a need for ground validation. We undertook first steps towards monitoring and understanding these processes during a fieldwork campaign to Union Glacier, in the Ellsworth mountains, where we performed diverse measurements, including shortwave and longwave radiation, albedo (ground-based and UAV-based), and water isotopes of blue ice samples to identify melt and refreezing.

388

Unraveling microbially-mediated iron and sulfur cycles in surface sediments of Potter Cove, a climate change hotspot

Dr. Graciana Willis-Poratti^1,2,3, Lea C. Wunder^3,4, Dr. David A. Aromokeye³, Dr. Tim Richter-Heitmann^3,4, Dr. Susann Henkel⁵, Dr. Susana Vazquez^2,6, Dr. Walter Mac Cormack^1,6, Dr. Michael W. Friedrich^3,7

¹Instituto Antártico Argentino, San Martin, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina. ³Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany. ⁴Max Plank Institute for Marine Microbiology, Bremen, Germany. ⁵Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ⁶Instituto de Nanobiotecnología (NANOBIOTEC) UBA-CONICET, FFYB, Universidad de Buenos Aires, Buenos Aires, Argentina. ⁷MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany

Abstract

Coastal sediments from the West Antarctic Peninsula receive significant amounts of metal oxide-rich fine-grained material washed away by glacial meltwater due to the ongoing climate change. The impact of the warming and progressive glacier retreat on the iron and sulfur cycles and the related microbial community in coastal sediments is poorly investigated. We studied the microbial community composition based on amplicon 16S rRNA gene sequencing in relation to geochemical parameters in surface sediments from Potter Cove (Isla 25 de Mayo/King George Island, South Shetland Island, Antarctica). Nine sites were investigated regarding their relative location to the glacier terminus and the discharge of surficial meltwater streams into the cove. Glacier front (GF) sediment samples show a broader ferruginous zone down to > 25 cm depth (Fe²⁺ up to 100 µM), compared to sediments located more distantly or influenced by surficial meltwater streams, where Fe²⁺ concentrations were higher (up to 800 µM) but became rapidly depleted at approximately 10 cm depth. The highest relative abundance of known iron-reducing microorganisms, mainly the family Sva1033, was found in sites close to the GF with up to 16% of total sequences. This clade was previously described as dissimilatory iron reducers in other permanently cold sediments. Sulfate concentrations decreased gradually over depth at some sites, suggesting ongoing sulfate reduction despite an apparent dominance of iron reduction. Known sulfate-reducing microorganisms (Desulfobulbales, Desulfobacterales) had a relative abundance as high as 30%, even at GF sites. Our study provides the first detailed characterization of microbial communities in Potter Cove sediments and their link with geochemical processes across the cove. This knowledge is critical in the context of increasing global warming in the West Antarctic Peninsula and allows us to better predict future environmental effects, particularly those related to organic matter mineralization and subsequent CO₂ release.

391

Relations between soils, vegetation types and active layer thickness at Signy Island

Nicoletta Cannone^1,2, Francesco Malfasi^1,2, Stefano Ponti^1,2, Alessandro Longhi^1,2, Peter Convey³, Mauro Guglielmin^1,2

¹Insubria University, Varese, Italy. ²Climate Change Research Center, Como, Italy. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Maritime Antarctica ecosystems are strongly affected by climate change impacts on active layer thickness (ALT), soil parameters, carbon cycle and vegetation, which could led to positive feedback on climate forcing. Changes in plant distribution due to climate change would directly affect the abiotic compartment. In this frame, the interaction between the soil and vegetation needs to be better investigated.

The main aims are to describe the soils of Signy Island (South Orkneys) with special reference to their types, physical and chemical characteristics, relations with ALT and vegetation at local scale. For this purpose, 28 sampling sites were selected all over the island according to topography and geological conditions, on different surface cover types and elevations.

At each site, a trench of at least 50 cm of depth was described and sampled. Soil temperature profile was recorded through a portable thermistor. Vegetation type, species composition and abundance were recorded in 22 sites on 1x1m plots, subjectively based as close as possible to the soil trenches and with comparable physiognomy and micro-topography. Soil samples were physicochemically characterized by analysis of water content, pH, electrical conductivity, total organic carbon were used to classify the soil according to US Soil Taxonomy. The assessment of nutrient contents was also carried out.

Soils were classified as Gelisols, belonging to Haplorthel (12), Haploturbel (15), Argiorthel (1) suborders, with mean total vegetation coverage between 67% and 80%. Haplorthels develope under a wider range of vegetation types, whereas Argiorthels with fruticose lichens and moss cushions only. Between the two most widespread soil types, pH, conductivity and LOI don’t show any significant differences, whereas nutrient contents show a wider variability in Haplorthels. Conversely, ALT shows a wider variability in Haploturbels, reaching values from 49 to 205 cm, with an overall mean value of 114 cm.

396

Investigating the drivers of abrupt Antarctic sea ice decline

Mr Chun Yin Chan¹, Dr Mark England¹, Dr James Screen¹, Dr Thomas Bracegirdle², Dr Ed Blockley³, Dr Caroline Holmes²

¹University of Exeter, Exeter, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³Met Office, Exeter, United Kingdom

Abstract

Antarctic sea ice cover experienced an abrupt decline in 2016, transitioning from a record maximum state to a record minimum state. However, the drivers of this rapid retreat are currently not well understood. Therefore, it is difficult to determine whether this signals the start of a long term melting trend, as has been long anticipated by climate models, or is an isolated episode of internal climate variability. In this study, we utilise the CMIP6 archive to understand if internal climate variability could be responsible for this Antarctic sea ice anomaly, and if so what the primary atmospheric and oceanic drivers are. This involves examining composites of the tropical teleconnections, subsurface ocean heat content, and high latitude atmospheric variability preceding extreme Antarctic sea ice anomalies in CMIP6 simulations. The primary objective is to elucidate the multifaceted factors influencing these extreme events, specifically addressing the 2016-2017 sea ice retreat, with lessons for 2023’s extreme Antarctic sea ice state. Initial results indicate that such events are possible in the absence of anthropogenic emissions in some climate models, although the occurrences are considered rare. We also show that using the limited observed record alone will underestimate the interannual variability of the Antarctic sea ice cover and therefore overestimate how rare such an anomaly would be. In fact, if we extend the observed record further back using statistical reconstructions, rapid declines of sea ice extent occurred in the early and mid 20th century. Our results highlight the importance of internal climate variability in the Southern high latitudes and advance our understanding of the drivers and predictability of Antarctic sea ice changes. We discuss the implications of this work for 2023’s record Antarctic sea ice anomaly.

399

Fossils that tell the story of Antarctica: A visit to the southernmost paleontological collection in the world.

Mrs Héctor Mansilla-Vera, Ms. Cristine Trevisan, Ms. Leslie Manríquez, Mrs Marcelo Leppe

Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

The Chilean Antarctic Institute, or INACH, houses a unique treasure trove of the past in Punta Arenas: the Paleobiology Laboratory. Within its specially conditioned spaces lies the Paleontological Collection of Antarctica and Patagonia (CPAP). This remarkable collection safeguards and facilitates the study of fossils originating from both the Antarctic territory and the southern of Patagonia.

Following strict protocols set by the National Monuments Council (CMN), the CPAP meticulously safeguards fossils from some of Antarctica's most challenging locations. These include Vega and Seymour Island in the remote James Ross Basin, as well as Snow, Livingston, Nelson, and King George Island in the South Shetland Islands, all part of the Antarctic Peninsula.

This includes everything from tiny marine invertebrates to ancient land plants, with the addition of fascinating remains of vertebrates. Notably, these fossils span the Mesozoic and Cenozoic eras, offering a remarkable record of biodiversity and a glimpse into the engrossing story of how life on Earth evolved during this period.

Uniquely in Chile, the CPAP stands as the sole space dedicated to the specialized study of Antarctica's paleontological history. This perfect alignment with the International Antarctic Treaty underscores the vital role of scientific knowledge gleaned through research

403

ITS_LIVE Version 2: A new generation of glacier observations

Chad Greene¹, Alex Gardner¹, Mark Fahnestock², Joseph Kennedy², Yang Lei³, Maria Liukis¹, Luis Lopez⁴, Johan Nilsson¹, Ted Scambos⁴, Forrest Williams⁵

¹Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA. ²University of Alaska Fairbanks, Fairbanks, USA. ³California Institute of Technology, Pasadena, USA. ⁴University of Colorado, Boulder, USA. ⁵California Institute of Technology, Fairbanks, USA

Abstract

The NASA MEaSUREs ITS_LIVE project has provided a decades-long record of ice sheet surface elevation observations and global glacier velocity estimates since 2018. We now present the first major update to the ITS_LIVE data suite, which includes a fully reprocessed velocity record, new cloud optimization, new ice-sheet calving front and surface elevation time series, and a host of new tools for working with the data. Velocity image pairs have been generated from all available optical and radar images acquired by the Landsat and Sentinel satellites, and advancements to the autoRIFT processing algorithm have resulted in higher precision, lower noise velocity measurements that bring a new level of detail to our understanding of global glacier movement. ITS_LIVE Version 2 supports fully cloud-based workflows, and in this talk we introduce the online tools we have developed to help cloud-curious users get started.

404

Greening Antarctica: the role of moss functional traits in ecosystem processes and climate interactions

Zoie Yetley¹, Scott Kiel¹, Becky Ball², Sarah Eppley¹, Todd Rosenstiel¹

¹Portland State University, Portland, USA. ²Arizona State University, Phoenix, USA

Abstract

Terrestrial biomes play an important role in regulating local and global climate feedback systems, a role that becomes increasingly critical as climate change accelerates. Maritime Antarctica, a region at the forefront of climate change, is experiencing rapid expansion of the terrestrial biome on newly exposed rocks after glacial retreat. Mosses dominate Antarctic flora, yet many of their functional roles within the ecosystem are far from understood. Previous studies in the Arctic have shown that mosses strongly influence ecosystem processes through abiotic and biotic interactions. This study investigates moss functional traits and their roles in ecosystem processes across a successional gradient on King George Island, Antarctica. From intensive plant sampling at three distinctive successional sites along Collins Glacier, we assessed five functional traits: nutrient accumulation, albedo, water-holding capacity, thermal conductivity, and decomposition. Our results reveal patterns of inter- and intra-specific variation in functional traits – in three dominant moss species across successional stages. Preliminary results show strong species-specific variation in albedo between Polytrichastrum alpinum and Sanionia uncinata, with low intraspecific variation among successional stages. These results begin to provide a conceptual framework for understanding plant functional roles across glacial succession in Antarctica and lend a better understanding to the effects of Antarctic greening and the driving forces of Antarctic climate systems.

406

Remnants of Eoarchean crust in the Napier Complex, East Antarctica

Prof. Monika A. Kusiak¹, Prof. Simon A. Wilde², Dr Daniel J. Dunkley¹, Prof. Martin J. Whitehouse³, Prof. Simon J. Harley⁴, Dr Anthony I.S. Kemp⁵, Dr Chris Fisher⁵, Dr Piotr Król¹, Dr Keewook Yi⁶

¹Institute of Geophysics Polish Academy of Sciences, Warsaw, Poland. ²Curtin University, Perth, Australia. ³3. Swedish Museum of Natural History, Stockholm, Sweden. ⁴University of Edinburgh, Edinburgh, United Kingdom. ⁵University of Western Australia, Perth, Australia. ⁶6. Korea Basic Science Institute, Ochang, Korea, Republic of

Abstract

The Napier Complex of East Antarctica is predominantly composed of ancient gneisses metamorphosed locally at ca. 2.8 Ga and more widely at ca. 2.5 Ga during an ultra-high temperature (UHT) event. Eoarchean remnants are present in the Napier Complex of Enderby Land in the western Tula Mountains and also in Kemp Land, with protolith ages up to 3.75 Ga. However, rare zircon in felsic orthogneiss records ages approaching 4.0 Ga at Mount Sones and Gage Ridge in the Tula Mountains; at Mount Jewell, Budd Peak and Mount Ryder east of the Tula Mountains; and at Aker Peaks in adjacent Kemp Land. Little is known about the relationship between these isolated outcrops of Eoarchean crust and their full extent is currently unknown. The Eoarchean protoliths from the Tula Mountains can be classified into two geochemical types, depleted and undepleted in Y-HREE-Nb-Ta. Depletion in Y-HREE-Nb-Ta likely resulted from high-pressure melting of basaltic crust, whereas low-pressure melting generated the undepleted granitoids. There is evidence of re-melting and recycling of crustal components throughout the Archean involving a range of sources and processes, and there is no simple correlation between geochemical type and age. The identification of Eoarchean crust at localities up to 300 km apart from Enderby Land into Kemp Land, indicates that ancient crust is widespread throughout the Napier Complex. Most likely, the Napier Complex is a composite of diverse crustal components that were assembled at ca. 2.5 Ga during the HT event.

Research conducted within grants UMO2021/43/B/ST10/03161 to DJD and RES-SE- SEP-SL-61901-1 to SAW.

407

Recent record-strong deepening of the Amundsen Sea Low: regional impacts and links to tropical variability

Kyle Clem¹, Vincent Favier², Ryan Fogt³, Benjamin Pohl⁴, Jonathan Wille⁵

¹Victoria University of Wellington, Wellington, New Zealand. ²Université Grenoble Alpes, Grenoble, France. ³Ohio University, Athens, USA. ⁴Université de Bourgogne Franche-Comté, Dijon, France. ⁵ETH Zurich, Zurich, Switzerland

Abstract

During the past decade, the Amundsen Sea Low (ASL) deepened at a record-strong and statistically significant rate during austral spring and summer. Associated with these circulation changes has been significant and record-strong warming across the Antarctic Peninsula region, marking a dramatic shift from the cooling observed there during the previous decade. Here we investigate what may have caused such rapid and unprecedented circulation changes, which, despite occurring over a short time period, can have longer-lasting effects on the coupled ice-ocean-atmosphere-biosphere system including jeopardizing ice-shelf stability. We focus on the role of recent large-scale atmospheric circulation changes, including the El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM). We find recent decadal trends in ENSO and SAM were strong and consistent with inducing ASL deepening, but these respective trends were not unprecedented. Instead, we find recent ENSO activity has featured unusual patterns of anomalous tropical convection, particularly over the South Pacific Convergence Zone, which has intensified the ENSO teleconnection over the South Pacific and strengthened the combined ENSO/SAM forcing of the ASL. These results suggest relatively subtle shifts in tropical dynamical forcing can have major impacts on regional Antarctic decadal climate variability.

409

Variability in embryo size of Antarctic krill: Implications for spawning grounds and recruitment

Professor Kim Bernard¹, Dr Robin Ross², Dr Langdon Quetin²

¹Oregon State University, Corvallis, USA. ²University of California Santa Barbara, Santa Barbara, USA

Abstract

Although Antarctic krill is one of the most abundant species on Earth, its populations are at risk from the combined effects of climate change and exploitation. There is evidence that krill populations in the Southwest Atlantic sector of the Southern Ocean have contracted southward over the last 90 years potentially caused by the southward relocation of their spawning grounds. Understanding the mechanisms leading to the shift in spawning grounds is critical for improving predictions of future krill populations. An important concept behind our knowledge of Antarctic krill spawning grounds is the assumption that krill embryos sink ~700 m before hatching, necessitating spawning over the deeper waters of the shelf break or over canyons and troughs on the shelf. However, the embryo-larva descent-ascent model used to determine this assumes a mean embryo starting diameter of 620µm. When larger embryos are applied to the model, hatching occurs near the surface. Using a long-term Antarctic krill egg production dataset (1993-2008) containing measurements of female krill and the embryos they produced, we investigated the inter-annual variability in the relationships of both the embryo starting diameter and batch size to female body length, as well as their impact on subsequent krill recruitment the following year. We used these data to develop empirical formulae that can be applied to models of the early life history of Antarctic krill to assist in the identification of spawning grounds. Our findings shed new light on the potential locations of krill spawning grounds and drivers of recruitment success.

412

Speaking up for albatross: Advocating for conservation through a museum exhibition

Dr Adele Jackson^1,2,3, Hatesa Seumanutafa¹

¹Canterbury Musuem, Christchurch, New Zealand. ²University of Canterbury, Christchurch, New Zealand. ³University of Tasmania, Hobart, Australia

Abstract

Albatross are facing crisis - population declines due to human activity are driving many species ever closer towards extinction. Yet, in many cultures, albatross are venerated as ‘creatures of legend, of poetry and of dreams.’¹ Attitudes towards albatross can be communicated through, and influenced by, their representation in art and in material culture. It follows that museums are well-placed to advance public understanding of albatross and to advocate for their conservation. This presentation focuses on preliminary research to develop a museum exhibition examining human relationships with albatross of the Southern Ocean. We describe a range of meanings and ideas associated with albatross found in the arts and in material culture; we discuss possibilities for the curation of such material into an exhibition to support public engagement and understanding of conservation imperatives; and we outline plans for a qualitative investigation of public responses to evaluate the exhibition’s success.

¹Roy, Jones and Fritter (2018) Albatross: Their world, their ways. Firefly Books, USA

416

Warming in the interior of East Antarctica driven by the change in the Southern Oceanic frontal zone

Mr. Naoyuki Kurita¹, Dr. Takao Kameda², Dr. Hideaki Motoyama³, Dr. Naohiko Hirasawa³, Mr. David Mikolajczyk⁴, Mr. Lee Welhouse⁴, Ms. Linda Keller⁴, Mr. George Weidner⁴, Dr. Matthew Lazzara⁴

¹Nagoya University, Nagoya, Japan. ²Kitami Institute of Technology, KItami, Japan. ³National Institute of Polar Research, Tachikawa, Japan. ⁴University of Wisconsin–Madison, Madison, USA

Abstract

East Antarctica has shown little warming in recent decades, in stark contrast to the warming trends observed in the Antarctic Peninsula and West Antarctica. However, the available observations are currently sparse and of short duration, and changes in surface air temperature (SAT) in the East Antarctic interior remain uncertain. Here we present a 30-year long temperature record for Relay Station in the interior of Dronning Maud Land (DML). The observations have been corrected, and the missing observations have been estimated using the corrected temperature data from the ERA5 reanalysis. The record shows a statistically significant warming trend of 0.5 °C/decade over the period 1993 – 2022. The strong warming during the warm season (from October to the following March) is the main reason for this trend. The interannual variability of warm-season temperatures is consistent with negative/positive pressure anomalies over the East Antarctica, as is the positive/negative phase of SAM. However, the warming is in the opposite direction to the SAM trend, which has shifted into its positive phase. The temperature increase is due to warm air advection from the anticyclonic circulation over the Southern Ocean (SO), which is associated with a weakening of the westerly jet stream. The westerly jet is anchored around the Southern Oceanic Frontal Zone (SOFZ), which has strong sea surface temperature (SST) gradients. Recent warming of the subtropical Indian Ocean (SIO) has resulted in the SOFZ to expand northwards, leading to a northward shift of the westerly jet. These changes are accompanied by increased anticyclonic circulation over the SO. Since warming over the SIO is primarily attributed to human-induced greenhouse gas influences, a continued increase in SAT in the East Antarctic interior is likely to be an early sign of global warming.

417

The Denman Terrestrial Campaign: an intensive, interdisciplinary science initiative to study a region of concern

Professor Nerilie Abram¹, the Australian Centre for Excellence in Antarctic Science²

¹The Australian National University, Canberra, Australia. ²The Australian Centre for Excellence in Antarctic Science, Tasmania, Australia

Abstract

Denman Glacier is a region of East Antarctica that may be particularly vulnerable to a warming climate. This sub-glacial basin has an extremely deep bed, has thinned and accelerated its ice loss in recent decades, and holds enough ice to raise global sea levels by around 1.5 metres if it fully destabilises. While it is understood that Denman Glacier is a region of concern, very few observations exist to be able to fully quantify and prepare for the risks posed by Denman Glacier in a warming world. During the 2023/24 Antarctic Summer the Australian Antarctic Program undertook a major interdisciplinary campaign to study the climatic, oceanographic, glaciological, and geological history and present-day characteristics of the Denman Glacier region. This presentation will summarise the achievements and preliminary findings of the research teams working through the Australian Centre for Excellence in Antarctic Science to better understand the Denman Glacier. The Denman Terrestrial Campaign also serves as an example of the value of interdisciplinary, multi-agency science campaigns to rapidly gather vast amounts of information for regions of concern in Antarctica.

419

Emerging tipping point elements in Antarctica

Professor Nerilie Abram^1,2, Dr Ariaan Purich^3,4, Professor Matthew England^5,6, Dr Felicity McCormack^3,4, Professor Dana Bergstrom⁷, Dr Tessa Vance⁸

¹The Australian National University, Canberra, Australia. ²Australian Centre for Excellence in Antarctic Science, Canberra, Australia. ³Monash University, Clayton, Australia. ⁴Securing Antarctica's Environmental Future, Clayton, Australia. ⁵The University of New South Wales, Sydney, Australia. ⁶The Australian Centre for Excellence in Antarctic Science, Sydney, Australia. ⁷The University of Wollongong, Wollongong, Australia. ⁸The University of Tasmania, Hobart, Australia

Abstract

Many parts of the Earth’s climate system are thought to be susceptible to rapid, irreversible and self-perpetuating change if warming exceeds their tipping point threshold. Established tipping elements mostly involve Northern Hemisphere components, and particularly the Arctic where climate warming is occurring at 3–4 times the global average. Here we assess the evidence for emerging tipping point elements in Antarctica by drawing together paleoclimate, observational and simulation data. These potential Antarctic tipping elements have previously been uncertain due to short observational records with large interannual variability and uncertainties in modelling the Antarctic and Southern Ocean system. We find that recent rapid sea ice declines around Antarctica rival the magnitude and climate amplification impact of Arctic sea ice losses, and that the circumpolar coherence of recent Antarctic sea ice changes point to a regime shift that is outside of expected natural variability. Similarly, new observations and improved model simulations for Antarctic Bottom Water formation indicate that a marked slowdown in this component of meridional overturning circulation is already underway, and may occur more rapidly than slowdown of the Atlantic Meridional Overturning Circulation. In addition to the well-established risk of West Antarctic Ice Sheet collapse, and more recently identified risks to East Antarctic subglacial basins, our findings point to multiple vulnerable tipping elements in the Antarctic climate system under even moderate levels of warming, with global consequences. Some biological tipping points in the Antarctic system are also expected to be linked to physical tipping elements, including rapid and irreversible loss of Emperor penguin populations and juvenile krill populations, while tipping elements in other Antarctic species or ecosystems may arise through the cumulative impacts of multiple human-caused pressures.

423

Monitoring Climate Impact on Permafrost in the Antarctic Peninsula: A 13-Year Study

Doctor Roberto Michel¹, Doctor Rafael Siqueira², Doctor Márcio Francelino², Doctor Thiago Pereira³, Doctor Carlos Schaefer²

¹Universidade Estadual de Santa Cruz, Ilhéus, Brazil. ²Universidade Federal de Viçosa, Viçosa, Brazil. ³Universidade Estadual de Minas Gerais, Frutal, Brazil

Abstract

Polar and subpolar regions featuring permafrost are widely recognized for their exceptional sensitivity to climate change. In the Antarctic Peninsula, there has been a notable warming trend of approximately 3.4 °C since the 1950s. In Hope Bay, in the northern Antarctic Peninsula, the evolution of ice-rich permafrost is as an indicator of recent climate change. The region has undergone rapid transformations, with the development of thermokarst in areas occupied by permafrost. This abstract presents a 13-year thermal monitoring (Feb 2011 to Jan 2024) of a sandy loam Haploturbels located at 150 m a.s.l. Daily average air temperature ranged between −26.1°C and 20.17°C with an average of −4.70°C during the studied period. Overall, 2022 was the warmest year, with mean air temperature of −2.90°C against −6.08°C in 2012. There was a correlation between air temperature and soil temperature along all monitored depth. Maximum monthly averages were recorded in 2013, 2015, 2016 and 2020 (8.78°C, 7.30°C, 9.19°C and 8.85°C at 5 cm). At the bottom of the profile (100 cm) maximum yearly averages occurred in 2016, 2022 and 2023 (-2.77°C, -2.56°C and -2.96°C) and maximum monthly averages were recorded in 2012, 2016, 2020 and 2023 (1.77°C, 1.85°C, 2.36°C and 2.03°C). The sum of the positive average daily temperatures did not exceed 9.0°C days in 2014 at the bottom of the profile (100 cm), reaching 49.4 °C days in 2022 and 70.2°C days in 2023. The freezing degree-days expressed the opposite tendency, −1589.8 in 2014, −1001.2°C in 2022 and -1158.5 in 2023. The active layer thickness varied considerably and reached its maximum between February and March every year. The calculated thawing depth reached minimum of 118cm in 2014 and maximum 200cm March 2022.

424

Progressive unanchoring of Antarctic ice shelves since 1973

Dr Bertie Miles, Prof Rob Bingham

University of Edinburgh, Edinburgh, United Kingdom

Abstract

Mass loss of the Antarctic Ice Sheet has been driven primarily by the thinning of the floating ice shelves that fringe the ice sheet, reducing their buttressing potential and causing land ice to accelerate into the ocean. Observations of ice-shelf thickness change by satellite altimetry stretch back only to 1992 and previous information about thinning remains unquantified. However, extending the record of ice-shelf thickness change is possible by proxy, by measuring the change in area of the surface expression of pinning points—local bathymetric highs on which ice shelves are anchored. Here we measure pinning-point change over three epochs spanning the periods 1973–1989, 1989–2000 and 2000−2022, and thus by proxy infer changes to ice-shelf thickness back to 1973–1989. We show that only small localized pockets of ice shelves were thinning between 1973 and 1989, located primarily in the Amundsen Sea Embayment and the Wilkes Land coastline. Ice-shelf thinning spreads rapidly into the 1990s and 2000s and is best characterized by the proportion of pinning points reducing in extent. Only 15% of pinning points reduced from 1973 to 1989, before increasing to 25% from 1989 to 2000 and 37% from 2000 to 2022. A continuation of this trend would further reduce the buttressing potential of ice shelves, enhancing ice discharge and accelerating the contribution of Antarctica to sea-level rise.

427

Metaverso Antártico: depicting Antarctic research and climate change through a videogame and virtual reality world.

Doctor Victor Fajnzylber

Universidad de Chile, XRLABS Transdisciplinary laboratory of virtual reality, videogames and emerging technologies, Santiago, Chile

Abstract

Metaverso Antárctico is a novel exploration adventure video game with science fiction elements and a solid scientific basis. Our game was created and produced by XR-LABS (Transdisciplinary Laboratory of Virtual Reality, Video Games, and Emerging Technologies at the University of Chile), with the advice of specialized researchers in biodiversity, conservation, and Antarctic governance. The first step in the development process was an expedition to the Weddell Sea where we recorded images and sounds, which inspired in the design of the game's landscapes and environments. Then, we selected a pool of 24 Antarctic species and conducted interviews with 14 Antarctic scientists specialized in those species.

The goal of the game is to study the adaptation of Antarctic flora and fauna to climate change. The video game has 3D format and a "Low poly" visual style. The player can explore on foot, dive, take samples on the floor and underwater, and interact with scientists, crossing seven different ecosystems: coastal rocks, green Antarctic, fresh water, sea ice, intermareal, marine bed, and pelagic area. We introduced an imaginary scan technology, which allows player to take samples of living species with a non-invasive method --reinforcing the ideas of respect and preservation of these ecosystems--.

Throughout this Antarctic world, the player can find previous researcher's diaries, which allow them to understand their research agendas for each ecosystem. We created a futuristic architecture with submerged laboratories to study underwater fauna in natural conditions. Finally, we combine the experience of a single player game with multiplayer online virtual reality.

Metaverso Antarctico gives us the opportunity to discuss the ways in which we can represent Antarctic research and the challenges of climate change through cinematographic and audiovisual arts.

428

High-resolution Mapping of Blue Ice on the White Continent

Dr. Shridhar Jawak^1,2, Dr. Alvarinho Luis³, Mr. Prashant Pandit^4,5, Mr. Sagar Wankhede^2,6, Prof. Dr. Peter Convey^7,8, Dr. Peter Fretwell⁷

¹The Climate and Environmental Research Institute NILU, Kjeller, Norway. ²Manipal Academy of Higher Education, Manipal, India. ³National Centre for Polar and Ocean Research (NCPOR), Vasco Da Gama, India. ⁴University of Trento, Trento, Italy. ⁵Institute for Earth Observation, Eurac Research, Bolzano, Italy. ⁶Parvatibai Chowgule College of Arts and Science, Margao, India. ⁷British Antarctic Survey, Cambridge, United Kingdom. ⁸University of Johannesburg, Johannesburg, South Africa

Abstract

Covering approximately 1% of the area of Antarctica (140,000 km²), blue ice areas (BIAs) are essential for understanding surface processes on the ice sheet. Around 17 dedicated studies were published between 1990 and 2023 which focus on blue ice mapping applications. Of these, only six attempted a continent-wide approach. None of these studies used very high-resolution (VHR) data. The mapping resolution achieved by existing methods varies from 30-200 m. The present study introduces a precise method for mapping BIAs at 2m resolution by leveraging very high-resolution WorldView-2 satellite imagery. The customized normalized-difference blue-ice index (NDBI) approach introduced by this study outperforms existing methods, providing a refined map for the Schirmacher Oasis region as an exemplar. The total BIA area in the study region is estimated to be 106.87 km². The present study’s results were validated using qualitative visual interpretation and thorough quantitative ground-truthing in field expeditions. Through this customized NDBI approach, VHR satellite data significantly enhances the accuracy and stability of BIA mapping. The method's superior performance is evident in its lower misclassification rate compared to target detection, spectral processing and pixel-wise supervised feature extraction approaches. The customized NDBI approach yields an average root mean square error (RMSE) of 654.48 ± 58.26 m², showcasing its robustness. The refined BIA map can contribute to improved mass balance estimates, facilitating studies on ice shelf stability, and supporting scientific missions seeking meteorites or ancient ice. Our findings not only offer a crucial tool for future polar research but also establish a robust methodology for mapping blue ice in challenging Antarctic terrains.

429

Analyzing Soil Thermal Dynamics in Patterned Ground Antarctic Permafrost: Keller Peninsula

Doctor Rafael Siqueira¹, Doctor Roberto Michel², Doctor Márcio Francelino¹, Doctor José Alexandre Demattê³, Doctor Danilo Mello¹, Doctor Carlos Schaefer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Estadual de Santa Cruz, Ilhéus, Brazil. ³Universidade de, São Paulo, Brazil

Abstract

The cryosphere stands out as one of the Earth's most sensitive components to climate change. In this context, permafrost holds significance as a crucial terrestrial element recognized for its extreme sensitivity to climate warming. Consequently, alterations in permafrost conditions will lead to profound changes in the Earth System. The goal of this abstract was to characterize the soil thermal conditions, along with its interannual variability from Feb 2011 to Dec 2023 at Keller Peninsula, King George Island, Maritime Antarctica, where six soil temperature probes were installed at varying depths (10, 30, and 80 cm) within both the polygon center and border (patterned ground) of a Turbic Lithic Cryosol (62° 05’ 09’’S, 58° 24’ 28’’W, 90 m a.s.l.). The soil thermal regime exhibited mean annual soil temperatures consistently below 0 °C (generally fluctuating around -1.5°C at all layers); being lower in 2011 and 2012. Differences below 0.2 °C were noted between consecutive soil layers (10–30 and 30–80 cm). Temperatures were warmer during 2018, 2021, 2022 and 2023. Soil temperatures were higher in the polygon border compared to the polygon center at 10 and 30 cm, with slight differences in the winter. The estimated active layer thickness varied considerably, minimum of 10 cm in 2014, 2016 and 2017; maximum of 98 cm in 2021 and 2023; for the rest of the studied period the deepest sensor had maximum temperatures around the freezing point indicating the presence of permafrost shallower then the 80 cm soil layer (in both polygon border and center). The absolute temperature difference between center and border were 0.29°C, 0.17°C and 0.07°C for the consecutive depths; the center presenting less amplitude and greater resistance in temperature change. The studied profile showed great variation in active layer thickness thus great response to climate variations.

430

Life on Antarctic nunataks: a multidisciplinary approach

Ana Aramburu¹, Leopoldo G. Sancho¹, José Raggio¹, David S. Pescador¹, Núria Beltrán-Sanz¹, Ana Pintado¹, Asunción de los Ríos²

¹Faculty of Pharmacy, Complutense University of Madrid, plaza Ramón y Cajal s/n, 28040, Madrid, Spain. ²Department of Biogeochemistry and Microbial Ecology, National Museum of Natural Sciences (MNCN-CSIC), c/Serrano 115 dpdo, E-28045, Madrid, Spain

Abstract

In Antarctica, habitats available for colonization are scarce due to the vast coverage of glaciers and permanent snow. However, ice-free rocky outcrops that emerge from glaciated areas -known as nunataks- provide ecological niches and constitute reservoirs of biodiversity since they served as glacial refugia during the Last Glacial Maximum. The cryptogams and lithobiont microorganisms that dominate these unique enclaves are strongly tied to their surrounding climatic conditions, which makes them particularly susceptible to the threat posed by different drivers of change. Studying the structure of these communities, understanding their responses to environmental factors, and determining their ecological boundaries is crucial to evaluate the current and potential impact of global change. We hereby present a multidisciplinary insight into the role of nunataks on terrestrial Antarctic ecology through the lens of cryptogamic and microscopic organisms from a prominent nunatak (449 m.a.s.l.) on Livingston Island combining microclimate, functional ecology, and biodiversity. Environmental conditions of the main topographical aspects of the nunatak were monitored year-long by a network of 14 microsensors. Photosynthetic activity of an Antarctic moss and lichen was evaluated by chlorophyll a fluorescence techniques and gas exchange experiments to assess their ecophysiological optimums and ranges of tolerance to ambient alterations. Cryptogamic vegetation was identified using morphological taxonomy and molecular strategies. A metabarcoding approach was implemented to characterize bacterial and fungal lithobionts from various microhabitats. Our ecophysiological studies hint that cryptogamic communities may be subjected to environmental filtering. The epilithic flora presents a remarkably high percentage of endemic lichens. Preliminary results suggest that there are distinct patterns of microbial colonization amongst the studied plots. Differences found in the microenvironmental conditions could be responsible for the dissimilarities detected at both bacterial and fungal community structures. It becomes evident that Antarctic nunataks host a vast hidden taxonomical and functional diversity awaiting to be unveiled.

432

Glacier movements in lower Taylor Valley during and following the Ross Sea I glaciation

Michael Stone¹, Dr Brent Goehring², Dr Peter Doran¹

¹Louisiana State University, Baton Rouge, USA. ²Los Alamos National Laboratory, Los Alamos, USA

Abstract

During the Ross Sea I glaciation, the Ross Ice Sheet (RIS) advanced along the Victoria Land coast, grounding in the mouths of several of the McMurdo Dry Valleys (MDV). This RIS advance is hypothesized to coincide with the retreat of alpine glaciers in the MDV. In Taylor Valley, a MDV blocked by the RIS during the last glacial stage, multiple hypotheses exist for how far into the valley the ice sheet extended. Some hypothesize that the RIS remained grounded at the mouth of the valley, while others propose that it advanced westward, penetrating deeper into the valley. Here, we examine physical evidence supporting the westward advance of the RIS beyond the mouth of Taylor Valley. We also present physical evidence suggesting that some of Taylor Valley's alpine glaciers advanced during the Ross Sea I glaciation. Exposure ages from in situ ¹⁴C cosmogenic radionuclide samples collected from RIS drift and end moraines beyond the termini of two modern alpine glaciers support our interpretations of the physical evidence. Based on these data, we present an updated hypothesis for Taylor Valley’s history during the last glacial stage. During the Ross Sea I glaciation, the RIS advanced westward into Taylor Valley, coinciding with the advance of Crescent Glacier on the south wall of the valley. The RIS then retreated, exposing its drift in lower Taylor Valley prior to ~32 ka. During or following this retreat, Canada Glacier on the north wall of Taylor Valley advanced, reworking the RIS drift. Crescent and Canada Glaciers then retreated toward their modern extent beginning ~24 ka and 13.5 ka, respectively.

435

Large ensemble simulations of Antarctic extreme seasons under 20th and 21st century climate change

Dr Tom Bracegirdle¹, Dr Thomas Caton Harrison¹, Dr Caroline Holmes¹, Dr Hua Lu¹, Dr Patrick Martineau², Mr Tony Phillips¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan

Abstract

Extreme seasons (climate extremes) are of particular relevance to impacts, as they can produce accumulated effects on, for example, surface melt of ice shelves and penguin breeding. There is a gap in knowledge on how extreme seasons may change over Antarctica and the Southern Ocean under future climate forcing scenarios, with Antarctica not included in the IPCC AR6 WG1 Chapter 11 on extremes. In this presentation, available large ensemble datasets in the Coupled Model Intercomparison Phase 6 (CMIP6) archive were used to provide the first multi-variate overview of the evolution of extreme seasons over Antarctica and the Southern Ocean during the 20^th and 21^st centuries, with projections following medium-to-high radiative forcing scenarios (SSP2-4.5 and SSP3-7.0 forcing experiments). The variables assessed were near-surface temperature, surface precipitation rate and near-surface westerly wind. The results show significant differences between simulated changes in background mean climate and changes in low (10^th percentile) and high (90^th percentile) extreme seasons. Regional winter warming is most pronounced for cold extremes, particularly over or near to areas of climatological 20^th century sea ice cover. In summer there are more pronounced increases in high extremes in precipitation and westerly wind during the ozone hole formation period (late 20^th century) affecting coastal regions and in particular the Antarctic Peninsula. At sub-polar latitudes (between 50 and 60 degrees South) there is an approximately 20% reduction in the range of summer season wind extremes. Potential mechanisms/processes responsible for these differences will be discussed.

444

Short-term interannual variation in macroalgal communities on the Western Antarctic Peninsula

Dr. Charles Amsler¹, Ms. Margaret Amsler¹, Dr. Andrew Klein², Dr. James McClintock¹

¹University of Alabama at Birmingham, Birmingham, AL, USA. ²Texas A&M University, College Staton, TX, USA

Abstract

There are numerous reports from the past five decades of macroalgal abundance in the undersea forests they dominate along the northern portion of the Western Antarctic Peninsula (WAP). However, there is little information about short-term variation in macroalgal abundance or in community structure. We recorded three replicate videos of vertical transects between 5 m and 40 m at each of four sites separated by <30 km near Anvers Island in 2019 and 2023, with two of the sites also recorded in 2020. At one site, only two of the transects were repeated in 2023. Total macroalgal cover increased between 2019 and 2023 in all 11 individual transects sampled in both years, with increases in brown, overstory macroalgal cover also in 10 of the transects. The understory red macroalgal cover decreased in all eight transects sampled both years at three sites – probably in part due to being beneath the increased overstory – but increased at the other site. There were no significant differences between total, brown, or red macroalgal cover between 2019 and 2020 in the two sites sampled then. Nonparametric, multivariate analyses of the communities identified significant differences in the macroalgal assemblages between all sites and between 2019 and 2023 at three of the sites but there were no significant differences in the macroinvertebrate assemblages across sites or years. Combined percent cover and quadrat biomass sampling enabled estimations of macroalgal biomass changes from the video data. The increases between 2019 and 2023 were substantial because they were primarily from increases in the large overstory browns. Sea ice concentrations were decreasing substantially across this time interval and could be a causal factor in the increased macroalgal cover and biomass. If so, it is likely that similar increases could have occurred across much of the WAP.

445

An investigation on the boreal summer moisture transport from the Antarctic to the Arctic and its relationship with the Indian summer monsoon

Dr. Suchithra Sundaram^1,2, Dr. Latha G¹, Dr. Deepa R³, Dr. Clare Eayrs⁴

¹National Institute of Ocean Technology, Chennai, India. ²WOSA, Department of Science and Technology, New Delhi, India. ³Independent Researcher, Louisiana, USA. ⁴Korea Polar Research Institute, Incheon, Korea, Republic of

Abstract

Atmospheric moisture transport is a crucial component of the Earth’s hydrological cycle, and the atmospheric branch of the water cycle is built upon by the moisture transport from oceans to continents via evaporation over oceans and precipitation over continents. An example of such a process is the Indian summer monsoon. This study investigates whether (i) the atmospheric and oceanic circulation changes over the Antarctic region contribute to the Southern Ocean moisture transport to the Indian monsoon region and (ii) the large-scale atmospheric circulation associated with the Indian summer monsoon influences the moisture transport to the Northern Hemispheric polar region.

An analysis of multiple datasets based on observational, reanalysis and satellite sources were carried out for seventy years (1951-2020). Preliminary analysis of rainfall (All India rainfall data (0.25° x 0.25°) from India Meteorological Department), atmospheric circulation (zonal and meridional wind, specific humidity, sea level pressure data (2.5° × 2.5°), from the National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis), and sea surface temperature (HadISST; 1° × 1° developed at Met Office Hadley Centre for Climate Research) show that many of the strong Indian summer monsoon years were accompanied by moisture transport originating from 38°S - 45°S and 50°E-75° E and it has observed that the moisture transport extends to high latitudes of Artic through the Peninsular India. Anomalous cooling of sea surface temperature is observed over the Subtropical High region of the Indian Ocean, indicating the need for further investigation into the Antarctic Oscillation’s influence on the initiation of moisture transport over the identified location. The study proposes a physical mechanism explaining a teleconnection linking the polar regions, where the Indian summer monsoon plays an important role.

Keywords: Indian Summer Monsoon, Moisture Transport, Teleconnection, Antarctic Oscillation, Subtropical High

446

Marine non-indigenous species arrival in Antarctica: investigating propagule pressure load and dispersion patterns associated to maritime traffic and seaweed rafts through modelisation approaches

PhD(c) Hélène Dubrasquet¹, Dr. David Donoso^2,3, Dra. Andrea Pinones⁴, Dra. Arlie McCarthy⁵, Ms William Lafarge⁶

¹Instituto de Ciencias Ambientales y Evolutivas (ICAEV), Facultad de Ciencias, Universidad Austral de Chile (UAch)., Valdivia, Chile. ²Instituto Milenio Biodiversidad de Ecosistemas Antárticos y subAntárticos (MIBASE), Santiago, Chile. ³Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. ⁴Instituto de Ciencias Marinas y Instituto de Ciencias Marinas y Limnológicas (ICML), Facultad de Ciencias, Universidad Austral de Chile (UAch)., Valdivia, Chile. ⁵Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany. ⁶Pôle Géomatique et Environnements Marins, Centre IFREMER de Brest, Plouzané, France

Abstract

For 33 million years, marine species living in Antarctic waters have been isolated from the rest of the Southern Ocean by deep continental shelfs and the presence of the Antarctic Circumpolar Current (ACC). However, climate change increasingly modifies local oceanographic conditions that allow subantarctic waters to breach the ACC and potentially bring with it non indigenous species (NIS) with cold-water affinities, while the increase of ice-free zone in the Antarctic intertidal will allow them to settle. It is expected that the number of species with cold-water affinities (i.e, subantartic, or with a bipolar or arctic distribution) that will reach and settle in Antarctica will raise in the following years, especially in the Western Antarctic Peninsula (WAP) where climate change is the fastest and human activities is the highest. In this work, we used GIS and the Regional Oceans Modeling System (ROMS) model to investigate the dispersion patterns and estimate propagule pressure load associated with maritime traffic and seaweed rafts at regional (throughout the WAP) and local scale (in previously identified vulnerable hot-spots for NIS arrival) using Ulva spp as model species. We released particles simulating Ulva spp propagules drift during a three summer months (January-February-March) experiment (when maritime traffic is the highest) with an interval of 15 days between each release event. We hypothesized that local oceanographic conditions define the main pathways and characteristics (residence time, exportation rate and number) of propagule at local and regional scale. We also hypothesized that propagule pressure estimates calculated in identified vulnerable hot-spots are higher when considering maritime traffic compared with natural transport through seaweed rafts, given the intensity of maritime traffic in the WAP. Our work provides the first numerical estimates for propagule pressure in the WAP considering the local oceanographical context, widening the application of modeling approaches to answer current biological questions.

448

Unique Antarctic stromatolites reveal diverse taxa and metabolic complexity: implications for the early evolution of life

PhD Lara Vimercati

Natural History Museum of London, London, United Kingdom. University of Colorado at Boulder, Boulder, USA

Abstract

Lake Untersee is a perennially ice-covered lake located in Queen Maud Land, Antarctica. This habitat serves as an ecological analog of early Earth and other worlds in our solar system characterized by thick permanent ice covers, such as Enceladus and Europa and even ancient ice-covered lakes on Mars. This unique environment supports a vast system of mat morphologies: pinnacles, flat mats and modern, large conical stromatolites. While pinnacles and flat mats are common throughout other Antarctic ecosystems, large complex cones are the first report of such structures in a modern environment. These stromatolites consist of a top pigmented layer of photosynthetic Cyanobacteria covering a soft structure of alternating laminations of sediment and microbial organic matter. These modern cone structures are extremely intriguing as Lake Untersee is the only environment on Earth where they have been found to date. We reconstructed metagenome-assembled genomes (MAGs) from bacterial phyla inhabiting pinnacle and cones that grow adjacently under the same conditions, including many rarely observed phyla. Microbial structures are inhabited by distinct communities with an abundant cyanobacterium Microcoleus defining cone-shaped structures and Elainellacea increasing in pinnacle-shaped structures suggesting cyanobacteria influence mat morphologies. We identified sharp partitioning from upper to lower mat layers in community composition and metabolic potential including abundance of photosynthetic pathways in the upper light-receiving laminae of the mat, and heterotrophic pathways in the lower layer. Metagenomic analysis shows that Lake Untersee is the first Antarctic Lake with substantial ammonia oxidising Nitrospiracea and amoA genes in benthic microbial mats. Genomic capacity for recycling is prevalent across MAGs, highlighting the importance of nutrient scavenging in ultra-oligotrophic environments. The next step we are working on is the generation of metatranscriptomes of several layers of conical stromatolites and pinnacles, which will allow to identify which microbial components are active and which genes of the community are expressed.

449

Recent Antarctic Sea Ice Extremes in the Historical Context of the 20th Century

Dr. Ryan Fogt

Ohio University, Athens, USA

Abstract

Antarctic sea ice has been behaving in dramatic ways in the last decade. After nearly 30 years of slow and steady growth in total Antarctic sea ice, record low extents were reached in 2017, 2022, and 2023. In 2023 alone, Antarctic sea ice was well below average for nearly the entire year, continuously setting records since its minimum in February, and advancing much slower than normal during the austral autumn and winter. While the current events appear extreme in the satellite observations, these records only reliably extend back until around 1979, making it challenging to truly understand the historical significance of these recent events. This talk will analyze these events, including the change from maximum in 2014 to minimum in 2017, and the 2022 and 2023 record lows, in the context of monthly and seasonally resolved Antarctic sea ice (both extent and concentration) reconstructions starting in the early 20th century. The large reconstruction ensembles enable a much wider understanding of the significance of these recent extremes in a much larger sample, better helping to determine if Antarctic sea ice is entering a new regime that it has not seen in the last 120 years. Impressively, the reconstructions indicate that recent changes are exceptional even in the context of over a million possible Antarctic sea ice states since the 20th century.

450

Phytoplankton as the crucial driver modulating CO₂ flux dynamics in different subregions of the Northern Antarctic Peninsula.

Pedro Senger¹, Raul Costa¹, Thiago Monteiro¹, Rodrigo Kerr¹, Tiago Dotto², Afonso Ferreira³, Eduardo Secchi¹, Carlos Rafael Borges Mendes¹

¹Universidade Federal do Rio Grande (FURG), Rio Grande, Brazil. ²National Oceanography Centre, Southampton, United Kingdom. ³Universidade de Lisboa, Lisboa, Portugal

Abstract

The Southern Ocean is responsible for over a third of the global dioxide carbon (CO₂) sequestration by the ocean, playing a key role in driving global biogeochemistry. Recent studies have pointed out that some phytoplankton functional groups along with non-biological drivers increase the CO₂ sink in the Southern Ocean over the seasons. In addition, it has also been appointed the inversely proportion between the chlorophyll-a (a measure of phytoplankton biomass) and the CO₂ flux (ΔpCO₂). The Northern Antarctic Peninsula (NAP), which has been experiencing drastic changes on ecosystems, sea ice and ocean dynamics, is considered one of the main gateways to the Southern Ocean. The NAP marine system is a diverse region featuring a range of oceanic and coastal ecosystems with complex hydrographic and biogeochemistry patterns. Considering the different areas along the NAP, we subdivided it into six subregions (Gerlache and Bransfield straits, coastal and oceanic Weddell, Drake Passage, and Bellingshausen influenced waters) in this study, analysing the contribution of phytoplankton on CO₂ fluxes. For that, we utilized both biological (phytoplankton community composition by HPLC-CHEMTAX approach) and physical-chemical data (e.g., macronutrients, temperature, ΔpCO₂). All subregions showed that the biology was the crucial driver modulating CO₂ flux dynamics. However, some subregions expressed more effect of phytoplankton (e.g., coastal Weddell and Bransfield Strait) than others (e.g., oceanic Weddell), acting as CO₂ sink areas, mainly associated with the high values of chlorophyll-a and a dominance of diatoms. An exception was observed for the Gerlache Strait, where the high chlorophyll-a values associated with a dominance of cryptophytes also contributed for the negative ΔpCO₂values. These results show as different phytoplankton community composition may drive different CO₂ fluxes among subregions along the NAP, increasing the knowledge about diatoms and cryptophytes on CO₂ uptake.

451

Frontal Ablation trends of the Manso Glacier, Monte Tronador

Licenciate Lautaro Clavero, Dr. Lucas Ruiz

IANIGLA-CONICET, Ciudad de Mendoza, Argentina

Abstract

Due to frontal ablation, calving glaciers show a more complex reaction to climate change than land-terminating glaciers. This is a significant challenge for assessing and forecasting ice mass loss from regions characterized by calving glaciers like Antarctica or the Patagonian Andes.

Here, we assess the role of frontal ablation in the mass change of Manso Glacier, one of the most voluminous glaciers of the Northern Patagonia Andes. To achieve this, we developed a method that calculates frontal ablation by segmenting the glacier front into a series of fluxgates and integrating them. This strategy allows us to differentiate areas of the glacier front that are advancing, stagnant, or retreating. The method requires flow line vectors, velocity grids, glacier extent masks, ice thickness, and surface elevation change data. Surface velocities were generated using feature tracking with Landsat 8 and Sentinel 2 optical images.

Since 2013, we have observed an increase in the calving speed of the glacier, reaching its maximum in 2019. However, since 2020, the frontal ablation rate has remained high because the front is at a thick section of the glacier, particularly on the southern margin of the glacier tongue. Between 2017 and 2022, frontal ablation represented 47% of the total ice mass lost, and both surface velocity changes and frontal change velocity control the frontal ablation rates.

Finally, our novel method has proved beneficial to monitoring the frontal ablation of medium-sized glaciers, and we hope it could help disentangle the mass loss by frontal ablation for major glaciers as well.

455

China’s Evolving Role in Antarctica: A Case Study in International Geopolitics

Rose Leeger^1,2, Dr. Nengye Liu³, Dr. Kevin Hughes⁴, Dr. Cassandra Brooks^1,2

¹University of Colorado Boulder, Boulder, USA. ²Institute of Arctic and Alpine Science (INSTAAR), Boulder, USA. ³Singapore Management University, Singapore City, Singapore. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

China is a newer member in a historically largely western driven institution of the Antarctic Treaty System (ATS). Signed in 1959 by the 12 original signatory Parties, the Antarctic Treaty now has 56 parties, with China signing in 1985. The governance of Antarctica is unique, as the Antarctic Treaty area is largely governed by consensus through the ATS. Designation of protected areas must be uniformly managed and decided upon by the Consultative Parties. Rapid geopolitical and environmental changes inherently influence the establishment and management of protected areas. China has been working towards increasing its engagement and voice worldwide, and this includes in Antarctic governance. As a Party with an increasing presence and increasing engagement in Antarctic affairs, China’s actions have provoked a variety of responses from other Antarctic Treaty Consultative Parties’. To understand China’s evolving role in the ATS, meeting reports (ATCM, CEP) and policy papers were analyzed to understand China’s increasingly vocal engagement in annual meetings, as well as timelines for different protected areas proposed. Parties’ responses are derived from the same sources, and we investigated how China’s engagement and response did or did not differ from that of other Parties. The increasing vocalization and expression of divergent views of China has raised anxieties within the West as concern on the shifting powers could influence international law and order. China, and other emerging actors, provide a new perspective than the original 12 signatories Parties, and geopolitics play a major role in protected area establishment. However, for the sake of Antarctic biodiversity and conservation measures, multi-party collaboration must be prioritized to decrease the effects of geopolitical influences.

466

Severe 21st-century ocean acidification in Antarctic Marine Protected Areas

Cara Nissen^1,2, Nicole Lovenduski¹, Cassandra Brooks¹, Mario Hoppema², Ralph Timmermann², Judith Hauck²

¹University of Colorado Boulder, Boulder, USA. ²Alfred Wegener Institute, Bremerhaven, Germany

Abstract

Antarctic coastal waters are home to several established or proposed Marine Protected Areas (MPAs) supporting exceptional biodiversity. Despite being threatened by anthropogenic climate change, uncertainties remain surrounding the future ocean acidification (OA) of these waters. Here we present 21st-century projections of OA in Antarctic MPAs under four emission scenarios using a high-resolution ocean–sea ice–biogeochemistry model with realistic ice-shelf geometry. By 2100, we project pH declines of up to 0.36 (total scale) for the top 200m. Vigorous vertical mixing of anthropogenic carbon produces severe OA throughout the water column in coastal waters of proposed and existing MPAs. Consequently, end-of-century aragonite undersaturation is ubiquitous under the three highest emission scenarios. Given the cumulative threat to marine ecosystems by environmental change and activities such as fishing, our findings call for strong emission-mitigation efforts and further management strategies to reduce pressures on ecosystems, such as the continuation and expansion of Antarctic MPAs.

467

21st-century environmental change decreases habitat overlap of Antarctic toothfish (Dissostichus mawsoni) and its prey

Cara Nissen¹, Jilda Caccavo^2,3, Anne Morée⁴

¹University of Colorado Boulder, Boulder, USA. ²LSCE/IPSL, Gif-sur-Yvette, France. ³LOCEAN/IPSL, Paris, France. ⁴University of Bern, Bern, Switzerland

Abstract

Antarctic toothfish are a commercially exploited upper-level predator in the Southern Ocean. As many of its prey, the ectothermic, water-breathing Antarctic toothfish is specifically adapted to the temperature and oxygen conditions present in the high-latitude Southern Ocean. Additionally, the life cycle of Antarctic toothfish critically depends on sea-ice dynamics and the transport of individuals with prevailing current systems between habitats with different prey distributions. To assess the impact of 21^st-century climate change on potential interactions of Antarctic toothfish and its prey, we here employ the extended Aerobic Growth Index (AGI), which quantifies the effect of ocean temperature and oxygen levels on a species' growth and health. We quantify changes in predator-prey interactions by a change in viable habitat overlap as obtained with the AGI. As environmental data, we use future projections for four emission scenarios from a model specifically designed for applications on and near the Antarctic continental shelf. For the two highest-emission scenarios, we find that warming and deoxygenation in response to climate change cause a subsurface decline of up to 40% in viable habitat overlap of Antarctic toothfish with important prey species, such as Antarctic silverfish and icefish. Acknowledging regional differences in the decline of viable habitat overlap, our results demonstrate that warming and deoxygenation alone could significantly perturb predator-prey interactions in the high-latitude Southern Ocean. As changing sea-ice conditions, circulation patterns and ocean acidification will additionally impact different life stages of high-latitude species to a varying degree, our findings highlight the need for a better quantitative understanding of cumulative climate-change impacts on Antarctic species to better constrain future ecosystem impacts of climate change.

468

A Regime Shift on Weddell Sea Continental Shelves with Local and Remote Physical and Biogeochemical Implications is Avoidable in a 2°C Scenario

Cara Nissen^1,2, Ralph Timmermann², Mario Hoppema², Judith Hauck²

¹University of Colorado Boulder, Boulder, USA. ²Alfred Wegener Institute, Bremerhaven, Germany

Abstract

Tipping points in the Earth system describe critical thresholds beyond which a single component, part of the system, or the system as a whole changes from one stable state to another. In the present-day Southern Ocean, the Weddell Sea constitutes an important dense-water formation site, associated with efficient deep-ocean carbon and oxygen transfer and low ice-shelf basal melt rates. Here, a regime shift will occur when continental shelves are continuously flushed with warm, oxygen-poor offshore waters from intermediate depth, leading to less efficient deep-ocean carbon and oxygen transfer and higher ice-shelf basal melt rates. We use a global ocean–biogeochemistry model including ice-shelf cavities and an eddy-permitting grid in the southern Weddell Sea to address the susceptibility of this region to such a system change for four twenty-first-century emission scenarios. Assessing the projected changes in shelf–open-ocean density gradients, bottom-water properties, and on-shelf heat transport, our results indicate that the Weddell Sea undergoes a regime shift by 2100 in the highest-emission scenario, SSP5–8.5, but not yet in the lower-emission scenarios. The regime shift is imminent by 2100 in the scenarios SSP3–7.0 and SSP2–4.5, but avoidable under the lowest-emission scenario SSP1–2.6. While shelf-bottom waters freshen and acidify everywhere, bottom waters in the Filchner Trough undergo accelerated warming and deoxygenation following the system change, with implications for local ecosystems and ice-shelf basal melt. Additionally, deep-ocean carbon and oxygen transfer decline, implying that the local changes ultimately affect ocean circulation, climate, and ecosystems globally.

469

Making the headlines: media representations of ice sheets and sea level rise between 2013 and 2023.

Dr Katie Marx¹, Professor Rebecca Priestley², Professor Elizabeth Leane¹

¹University of Tasmania, Hobart, Australia. ²Victoria University of Wellington, Wellington, New Zealand

Abstract

Broadscale support for the type of climate action necessary to avoid extreme sea level rise from Antarctic ice melt will depend on an engaged and informed public. Most people, however, will never visit Antarctica in person and rely upon cultural texts, including news reports, to understand the Southern Polar region. To strengthen global engagement with issues such as Antarctic ice melt, we need to understand the role these cultural texts play in shaping public knowledge and opinion. In this paper we bring a broad humanities and social sciences perspective to examine representations of the Antarctic ice sheets, and the relationships between Antarctic ice melt and sea-level rise, in news media, with a focus on representations of ice sheet instabilities and climate-ice sheet tipping points.

Our mixed methods analysis of Anglophone news headlines from the last decade (2013 to 2023) will identify how the relationship between Antarctic ice sheets and sea levels is depicted in the media and how this depiction has changed over time. Preliminary results show an increase in news coverage in the last decade, along with increasing prevalence of words such as ‘melting,’ ‘collapse’, and ‘accelerating’. We will present on these findings through this paper, with a view to commenting on how researchers can best leverage media coverage to strengthen public engagement on issues relating to Antarctica and climate change.

470

Whaling, colonialism, and ideas for a legal framework in the Antarctic in 1940

Dr Ursula Rack

Gateway Antarctica, School of Earth and Environment, University of Canterbury, Christchurch, New Zealand

Abstract

At the beginning of World War Two, a PhD student in international law in Germany discussed in his dissertation the issue with claiming countries in the Antarctic and explored ways to create a legal framework to manage the processes of land entitlements. One of the reasons to claim land on the Southern continent was industrial whaling. Germany had plans to claim land for their own whaling enterprises, but it never materialised. When this PhD was published, Argentina and Chile not even had laid their claims. However, Norway just claimed a part of the Antarctic before the German Schwabenland Expedition arrived in 1939, which had the same intention on that land.

This paper will focus on the historical developments discussed in this particular PhD, and its attempt to introduce legal frameworks to govern the Antarctic with its claiming practices. We do not know how the PhD author, Hans Georg Baare-Schmidt, reacted to the development of the Antarctic Treaty. However, his study shows first attempts towards an international law that could be seen as an idea of the Antarctic Treaty. Baare-Schmidt worked as a lawyer in Germany and died in 2010.

471

Sharing and accessing Antarctic Data through the US Antarctic Program Data Center (USAP-DC)

Frank O. Nitsche, Kirsty Tinto, S. Isabel Cordero, Alex Strong, Ngoc B. Truong

Lamont-Doherty Earth Observatory of Columbia University, Palisades, USA

Abstract

Availability and findability of existing data is key: for reuse of the data; for open, reproducible science; and, for enabling data comparison, compilations and analysis of historical developments. This is especially true for Polar Regions, where logistical challenges and rapid changing environments often result in unique datasets.

The US Antarctic Program Data Center (USAP-DC) is a data hub and repository funded by the US National Science Foundation. We are committed to supporting researchers in their data needs, to preserving valuable Antarctic data, and to making these data findable, accessible, interoperable, and reusable. USAP-DC is a repository for any data collected or created as part of the US Antarctic Program, but also links to datasets at other repositories through dedicated project pages for NSF awards and projects.

Datasets are hosted with extensive metadata and are shared through multiple avenues to maximize findability. This includes free-text and map-based search interfaces and a browser on the USAP-DC website. In addition, we offer a REST API for machine access to the metadata. We also share metadata and dataset links through multiple metadata catalog services including the Antarctic Metadata Directory (AMD), DataONE, and Polar Federated Search while also enabling other search engines to harvest schema.org information directly from our dataset pages.

Recently, we developed a dataset metric to provide better feedback for users to improve the FAIRness of their data submissions. We plan to further improve metadata and dataset standards through collaboration with different user communities by providing updated guidance and templates for dataset submission.

473

Searching for larval habitats of Trichocera maculipennis on King George Island

Dr Andrey Przhiboro

Zoological Institute of the Russian Academy of Sciences, St Petersburg, Russian Federation

Abstract

The invasive winter fly Trichocera maculipennis (Diptera: Trichoceridae) has colonised seven stations on King George Island, the South Shetland Islands. Larval habitats of this species include terrestrial wet and semiaquatic organic-rich substrates. The known populations of T. maculipennis on King George Island inhabit mostly sewage treatment plants, but potential establishment of the species in natural Antarctic habitats may be catastrophic as saprophagous larvae can greatly alter the existing environment. During the 2019/2020 season, I conducted a survey to locate larval habitats of T. maculipennis in anthropogenic habitats (indoor and outdoor) of Bellinshausen Station and to assess the presence of this species immatures in selected natural habitats on Fildes Peninsula, King George Island, and on surrounding islets. The population of T. maculipennis (larvae, pupae, adults) was found in one indoor site of Bellinshausen Station but no specimens or traces were found in other indoor and outdoor sites of the station, including the places where it occurred in previous seasons. To ascertain if established populations already exist in natural ecosystems, twelve different-type organic-rich wet habitats situated in ten localities were examined for the presence of immatures or traces/remains of T. maculipennis. Based on published data and own observations on the larval bionomics of this species, I searched the habitats potentially most attractive and suitable for the development of larvae. Four sites examined were situated near Bellingshausen Station, while the others were several kilometers away from any station. No specimens or remains were found in any habitats and localities. My preliminarily conclusion is that there is no evidence for the establishment of T. maculipennis in natural habitats of King George Island. The laboratory tests confirmed that the larvae of T. maculipennis from Bellinshausen Station are able to complete development in organic-rich substrates from natural habitats of the island, indicating the risk of their colonisation.

476

Artists in Antarctica: Curating and Celebrating Artistic Creativity in a Frozen Land

Dr Patrick Shepherd

University of Canterbury, Christchurch, New Zealand

Abstract

2023 saw the publication of Artists in Antarctica: Creativity in a Frozen Land by Massey University Press. The book contextualises the broad topic of Antarctic Arts through the work of 36 New Zealand artists who have headed to Antarctica as part of Antarctica New Zealand’s various artists and community programmes, providing an illustrated narrative that links the scientific/natural landscape with art. It also adds to the discussion around the value that Art has in representing Antarctic issues and New Zealand’s relationship with the continent.

Artists in Antarctica also includes commentaries by the artists about their experiences down on “The Ice”, as well as the artistic challenges and insights into the creative processes used in producing these artworks, examining the particular arts practices of the individual artists and the impact this unique experience has had on their work generally.

This paper traces the project from inception to publication and identifies the key aspects of curating and celebrating the work of such a diverse range of artists, as well as summarising some of the general themes arising from the artist interviews.

Shepherd, P. (Ed.). (2023). Artists in antarctica. Massey University Press.

477

Herbarium and living mosses as rich archives of past Antarctic microclimates

Dr Melinda Waterman^1,2, Professor Barbara Bollard^1,2, Professor Angelica Casanova-Katny^2,3, Professor Gustavo Zúñiga^2,4, Professor Margaret Barbour^2,5, Dr Quan Hua^2,6, Professor Sharon Robinson^1,2

¹School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ²Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, Australia. ³Facultad de Recursos Naturales, Universidad Católica de Temuco, Wollongong, Australia. ⁴Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile. ⁵School of Science, University of Waikato, Hamilton, New Zealand. ⁶Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia

Abstract

Monitoring continental and maritime Antarctic terrestrial ecosystems is increasingly important as they face an uncertain future due to changes in climates at various scales. Linking changes in health and biodiversity to climate is difficult as weather records are sparsely distributed, limited to a few decades or less, or simply do not exist. Additionally, many coastal ice-free areas rich in biodiversity are too far away from the locations of ice-core records and have unique microclimates. Hence, there is substantial need for climate proxies for areas where this biodiversity lives.

Restricted to the limited ice-free areas, mosses dominate the terrestrial plant-life of the frozen Antarctic landscape and are home to diverse communities of invertebrates and microorganisms. As resilient plants with simple structures, mosses can capture and preserve long-term records of their immediate microclimate as chemical signatures in their tissues. We discuss how mosses provide a temporal and spatial history of their local microclimates and growth rates through preserved chemical signatures.

We show that fresh and herbarium moss specimens have considerable potential as climate proxies. Living and herbarium moss cores provide high-resolution archives, at annual to decadal scales, of at least 100 years. By subsampling from herbarium specimens collected over 30 years ago, we have expanded our rich dataset to several remote sites and eras. Our results reveal that old-growth moss forests in various specially protected areas (ASPAs) and sites near research stations have experienced rapid drying. Applying these measures to samples collected from more coastal sites may allow us to determine how extensive changes in climate are across Antarctica. As well as determining the impacts of recent disturbance from stations, this work will help to identify terrestrial sites, including ASPAs, that are at risk in order to inform critical conservation efforts in a rapidly changing environment.

478

When Science Cannot Contain Politics, the Law Should Prevail! Recent conundrum regarding Antarctic Treaty Consultative Party Status

Professor Akiho SHIBATA

Kobe University PCRC, Kobe, Japan

Abstract

At the 2023 Antarctic Treaty Consultative Meeting (ATCM) held in Helsinki, Finland, a secret plenary meeting was held to discuss one of the most controversial agenda items of this meeting: an acknowledgment of Consultative Party status of two Contracting Parties to the Antarctic Treaty, namely Belarus and Canada. After an extensive and "acrimonious" consultation, both applications were rejected/postponed. The Final Report languages indicate there were politics involved in the Consultative Status acknowledgment process, one explicit (Ukraine war) and another implicit (non-change of positions by China and Russia). The Belarusian and Canadian cases were the second and third requests in which the new guidelines as provided in Decision 2 (2017) on the procedures to be followed with respect of Consultative Party status were applied. Shockingly, all three including Venezuela in 2018 have failed to achieve the status so far.

Originally, Decision 2 (2017) on the Consultative Party acknowledgment procedure with its criteria for "substantial scientific research activity there (in Antarctica)" as provided in Art IX (2) of the Antarctic Treaty was expected to provide objectivity and foreseeability in the Consultative Party acknowledgment procedure. However, the above recent cases suggest uncertainties, prolongation and potential politicization of the said procedure, which is a serious concern for Antarctic national programmes and policy-makers eager to effectively participate in the Antarctic governance based on the Rule of Law.

In light of these worrisome practice, this paper first re-affirms the relevant texts of the Antarctic Treaty and the original rationale of the Consultative Party acknowledgement criteria and procedure; second, in light of such reaffirmation, critically examines the recent practice focusing on Decision 2 (2017); and, finally, provides some policy suggestions for future course of actions to address this conundrum.

480

Distinct spatio-temporal patterns in microeukaryote phytoplankton communities revealed along the nearshore Antarctic Peninsula (61S- 68S)

Allison Cusick¹, Martina Mascioni^2,3, Alaina Smith¹, Christian Johnson^1,4, Chase James¹, Anesse Pinpokintr¹, Hong Zheng⁴, Andrew Allen^1,4, Maria Vernet¹, Rick Reynolds¹

¹Scripps Institution of Oceanography, La Jolla, USA. ²Universidad Nacional de La Plata, la plata, Argentina. ³consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires, Argentina. ⁴James Craig Venter Institute, la jolla, USA

Abstract

The nearshore regions of the Antarctic Peninsula remain relatively under sampled in capturing complete seasonal phytoplankton community dynamics due to sampling variations, limited access, and harsh environmental conditions. This study, conducted between 2017 and 2022 along the Antarctic Peninsula (61°S-68°S), analyzes molecular samples collected through the citizen science initiative FjordPhyto, and examines micro- and nano-eukaryote community structure across 32 sites within four distinct geographical regions between the months of November and March. The total of 271 surface net seawater samples collected result in a large Antarctic protist-focused molecular dataset (18Sv9). We report on seven photosynthetic groups: diatoms, dinoflagellates, small flagellates, cryptophytes, haptophytes, rhodophytes, and green algae. Through cluster analysis, three distinct assemblages were identified, predominantly characterized by high relative read abundances of either Porosira_sp., Geminigera_cryophila, or diverse mixed-diatom taxa. These recurrent communities exhibited characteristic diversity and succession patterns across four years, occurring in particular locations and particular times either early- mid- or late- season. High frequency of sampling revealed higher diversity in Antarctic photosynthetic protists than previously reported. Species evenness, richness and community diversity estimated with the Shannon Index were characteristic of each of the communities and exhibited significant variability depending on location and month sampled. Although cryptophytes had a widespread distribution and dominated one of the three communities, more than eighty percent of the samples were dominated by either of the two communities of diatoms. The findings underscore distinct community compositions that consistently characterize this region and offer a comprehensive seasonal overview of microeukaryote dynamics, aiding in the understanding of the role of primary producers in coastal ecosystems. This analysis paves the way for further exploration of the environmental drivers and ecological integration, advancing knowledge of biodiversity and biogeography in polar regions.

483

The JH bands imaging of Antarctic InfraRed Binocular Telescope (AIRBT) from Dome A in 2024

Bin Ma¹, Yi Hu², Zhaohui Shang², Michael Ashley³

¹Sun Yat-sen University, Zhuhai, China. ²National Astronomical Observatories, CAS, Beijing, China. ³University of New South Wales, Sydney, Australia

Abstract

Dome A, Antarctica is recognized as a superb site for infrared observations, thanks to its extremely dry and cold conditions. To take advantage of it, we have developed Antarctic InfraRed Binocular Telescope (AIRBT). It consists of two identical optical tubes, each with a diameter of 15 cm, and two InGaAs cameras with J, H filters, respectively. Following comprehensive testing, AIRBT was deployed at Dome A in January 2023, and was maintained in January 2024. Since then, it has been monitoring the sky remotely and automatically. The depth of 3-second exposures approaches 7.7 (6.8) mag in J (H) band during polar day in February, then extends to 12 (10) mag in J (H) band during twilight in March. Here we will describe the observations and data collected by AIRBT from Dome A in 2024, alongside presenting the preliminary results. By photometry, we aim to search for variable stars, and transients, as well as to measure the infrared sky brightness at Dome A.

484

The Best Available Science paving the way for Integrative Negotiation: a situational analysis of ASPA 178

PhD Candidate Marco Volpe

University of Lapland, Rovaniemi, Finland

Abstract

The Best Available Science (BAS) refers to utilising the most reliable, up-to-date, scientifically sound information and evidence to inform decision-making. Antarctic Special Protected Areas (ASPAs) are proposed by one or multiple parties and, upon scientific-informed knowledge informing decision-making, are negotiated and managed by parties. In this context, BAS not only enhances negotiators’ effectiveness, but also represents a source of power during negotiations. ASPAs are mostly regarded as valuable mechanisms to foster international scientific cooperation, however, they also represent an element of territoriality, which is often associated with national interests and a potential threat to reach successful outcomes.

The negotiation process is a key moment of balancing interests and reaching mutual benefits, and the outcome is dependent on the party’s acceptance/rejection/interest. Distributive Negotiation maximises each of the parties' share at the expense of the other party, it includes an adversarial position focusing on dividing resources and results in a win-lose or zero-sum negotiation. Integrative Negotiation aims to reach mutual gain by identifying shared interests and creating mutual benefits resulting in a zero-sum game.

China's dynamism in the polar regions and the increasing funding dedicated to polar science have raised scepticism about China’s long-term intentions among polar stakeholders.

Against this background, the study focuses on ASPA 178, which was recently negotiated between China, Italy and South Korea. The study investigates how BAS paves the way for the conflict-lowering potential of integrative negotiation shaping ASPA 178 creation and it is based on semi-structured interviews with scientists and diplomats involved in the negotiation. Situational analysis is used to depict actors and to gain knowledge about the interdependence and power relations between groups and actors involved.

485

International Rules for Antarctic Tourism: Current Situation, Trend Analysis and Countermeasures

Mr Shuangjian Li, Ms. Ao Yu

National Marine Data and Information Service, Tianjin, China

Abstract

With the rapid development of the global economy and the significant improvement of human living standards, the spiritual and cultural needs of residents of all countries are increasing, and the unique charm of Antarctic tourism has become a new hot spot of global consumption. Especially after the COVID-19 epidemic, the Antarctic tourism market has ushered in a recovery boom, and the number of tourists in the 2023-2024 Antarctic tourism season has exceeded 110,000, surpassing the highest level before the epidemic.As the number of Antarctic tourists continues to surge, the Antarctic ecological environment is facing unprecedented pressure, and it is more urgent than ever to formulate and improve international rules for Antarctic tourism activities. At present, the international governance of Antarctic tourism has realized the combination of hard law and soft regulations, building on the principles of the Antarctic Treaty and the Protocol on Environmental Protection, the basic rules and institutional framework based on ATCM measures, resolutions and IAATO industry regulations. However, there are still institutional drawbacks, which can not meet the needs of standardized management of Antarctic tourism. In light of the special realities of Antarctic tourism governance, Antarctic tourism management should be promoted from three aspects: the improvement of internal policies and regulations of the parties to the Antarctic Treaty, the establishment of international communication platforms and the formulation of specific guidelines for the Antarctic region, so as to jointly improve the global governance rules system for Antarctic tourism.

492

Antarctic tectonic boundaries reviled by multiscale lithospheric heterogeneity

Lu Li¹, Alan Aitken^1,2

¹School of Earth Sciences, The University of Western Australia, Perth, Australia. ²The Australian Centre for Excellence in Antarctic Science, Perth, Australia

Abstract

Antarctica has a unique location as the keystone of former Gondwana. Beneath its icy surface lies a geologically complex yet poorly understood continent. To advance our understanding of supercontinent evolution and Antarctica's tectonic history, it's essential to map the lithospheric heterogeneity. Benefiting from recent continental-scale geophysical data compilations, a series of models has been generated to represent this lithospheric heterogeneity. This includes information on sedimentary basins, basement structure, variations in crustal density and thickness, as well as the thermal and compositional structures of the lithosphere. A multiscale linear analysis method has been applied to identify potential boundaries across different scales. These identified lithospheric domain boundaries enhance our understanding of the continent's deep structure. Joint analyses of the lithospheric structure indicate that inherited Precambrian structures and their rheological contrasts controlled the continent's response during the breakup of Gondwana.

493

Triangulating for the human: the material record and a digital future

Mr Ieuan Hopkins¹, Dr Elizabeth Lewis Williams², Ms Angela Posada-Swafford³

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of East Anglia, Norwich, United Kingdom. ³Independent, Miami Beach, USA

Abstract

The British Antarctic Survey archive is a uniquely comprehensive and detailed account of British scientific endeavour in Antarctica from the 1940’s to the present day. Expressed in textual, visual and audio form, in analogue and digital, the archive contains formal and informal records ranging from personal correspondence to scientific data. The collection metrics suggest the archives’ size: 1.1 linear kilometres, 170m³ and 52,000 catalogue entries. But these figures do not convey the vast meshwork of intersecting pathways and individual stories contained within the archive which spring to life when you access them.

Take a single traverse route on one of the first surveying expeditions – a journey measured on a human scale. There are employment records for the men on the expedition, personal artefacts and letters, dog cards for the sledging team, field notes and triangulation figures. Photographs show what the men were seeing when they had their feet on the ice, at a particular moment in time; maps produced after their return illustrate their journey from above, the satellite perspective, details of triangulation points carefully marked and coded. What the map does not reveal is the human experience, the rhythms of work, the impact of the weather – and what it meant to be seeing this erstwhile pristine, hostile, beautiful environment for the first time.

This presentation will look at two different expeditions, a long-distance survey journey by dog sledge in the mid-20th Century and a personal account of the last Antarctic flight of NASA’s Operation IceBridge as it passed the torch to the ICESat-2 satellite. We will consider some of the implications of satellite surveys, and increasing digitisation, for the material archive, and open a conversation about reducing our carbon footprint whilst at the same time preserving a human perspective on Antarctica.

497

Antarctic ice shelves at risk of collapse by mid-century

Dr. Yaowen Zheng, Prof Nicholas Golledge, Dr. Alexandra Gossart

Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand

Abstract

Antarctic Surface melt has been identified as a crucial factor menacing ice shelf stability (Rott et al. 1996, van den Broeke 2005, Trusel et al. 2015) through mechanisms of hydrofracturing (Lai et al. 2020). Projections have shown that the magnitude of surface melt will increase and the melt extent will be widespread (Trusel et al. 2015, Gilbert & Kittel 2021). However, the distribution of future melt is not well known at high spatial resolutions, which limits the accurate estimation of surface water availability over the ice shelf areas that contain fractures (Lai et al. 2020), are vulnerable to hydrofracturing (Lai et al. 2020), and provide buttressing effects (Fürst et al. 2016). Here, we present 100-meter projections of AIS surface melt under the latest IPCC AR6 SSPs 1-2.6, 2-4.5, 3-7.0, and 5-8.5 scenarios. These projections are generated from an empirically-calibrated and spatially-parameterized Positive Degree-Day (PDD) model that incorporates 100-meter topographic variability to downscale forcing temperature fields. We show that the effects of high-resolution topographic variability can produce local temperature corrections of a similar magnitude to global temperature warmings under the highest greenhouse gas emissions scenarios at the century-end (Arias et al. 2021). We find that the Larsen-C, Shackleton, Thwaites, and Totten ice shelves will all be at high risk of collapse in this century due to increased surface melt if emissions follow the SSP3-7.0 pathway. However, CMIP6 GCMs currently only identify Larsen-C as being at risk. We further calculate the trajectories of latitudinal melt migration and show that the melt trajectories are dependent on climate change mitigation, and that SSP1-2.6 is likely the only emissions pathway under which future AIS surface melt is stabilized.

500

Largest Adélie population of the Antarctic Peninsula Region now under protection

Fritz Hertel¹, Osama Mustafa², Christian Pfeifer², Marie-Charlott Ruemmler²

¹German Environment Agency, Dessau-Rosslau, Germany. ²Think Ltd, Jena, Germany

Abstract

According to the Environmental Protocol to the Antarctic Treaty, protected areas in the Antarctic can be designated according to various categories. There are currently 76 so-called Antarctic Specially Protected Areas (ASPA), predominantly terrestrial areas that prioritise the conservation of certain values. The Treaty Parties have committed themselves to establish a coherent network of representative protected areas and have also repeatedly recognised that the current set of ASPA is still inadequate. The most recent addition dates from 2024 and is the first to be the result of a German initiative, with the USA as a co-proponent. This is ASPA Danger Islands, an archipelago at the tip of the Antarctic Peninsula consisting of seven islands of different sizes. The reasons for its designation as a protected area are manifold and range from the conservation of scientific to aesthetic values. The Area is characterised by its outstanding biodiversity, with the Adélie penguin playing the leading role among the at least ten seabird species that breed there. With more than 750,000 breeding pairs, it is home to the largest known colony of this species in the entire Antarctic Peninsula Region. And this population is also subject of scientific interest. It is, for example, not yet understood why such a huge Adélie colony is situated so far north compared to other Adélie colonies of similar sizes. To answer this and other questions, various studies which includes a monitoring of the local bird population of the Area are envisaged. Further investigations on the penguin foraging areas should complete first insights. In addition, future studies should also provide a picture of the Area’s vegetation. The overall aim of the new conservation status is to protect the outstanding terrestrial life from disruptive influences, while at the same time ensuring further scientific exploration of the Area.

501

Monitoring for impacts: is CCAMLRs Ecosystem Monitoring Program fit-for-purpose?

Professor Andy Lowther¹, Dr Chris Oosthuizen², Dr Stefan Schoombie², Mr Angus Henderson³, Dr Federico Sapriza⁴, Dr Manuel Novillo^5,6, Mr Elling Johannessen¹, Dr Ulf Lindstrøm⁷, Dr Bjørn Krafft⁸

¹Norwegian Polar Institute, Tromsø, Norway. ²University of Cape Town, Cape Town, South Africa. ³University of Tasmania, Tasmania, Australia. ⁴Independent Researcher, Montevideo, Uruguay. ⁵Instituto de Diversidad y Ecología Animal (IDEA-CONICET),, Cordoba, Argentina. ⁶Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Buenos Aires, Argentina. ⁷Institute of Marine Researrch, Tromsø, Norway. ⁸Institute of Marine Research, Bergen, Norway

Abstract

Fishing is widely regarded as one of the most important direct drivers of change in marine ecosystems the past century, impacting structure, function, and biodiversity. In the Antarctic, the fishery for Antarctic krill is the largest by volume, currently harvesting approximately 450,000 tonnes each year. Historical, unregulated catches of krill in the late 1970s prompted the establishment of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) in 1982 under the Antarctic Treaty System as a structured mechanism to prevent overfishing and potentially negative effects on the ecosystem. In 1989, CCAMLR established its Ecosystem Monitoring Program (CEMP), designed to detect and record significant changes in critical marine ecosystem components, and distinguish between ecosystem changes driven by fishing and environmental variability. The program is currently active in 13 locations around Antarctica monitoring eight selected indicator species consisting of breeding adult penguins, adult female Antarctic fur seals and their pups and three species of flying seabirds. Despite considerable improvements to our understanding of how the ecosystem functions and the technologies available for conducting monitoring, the indices monitored have not changed since CEMPs inception. We present published research on three members of the air-breathing krill predator guild currently not considered within CEMP (nonbreeding adult penguins, adult male Antarctic fur seals and baleen whales); and place their life histories in the context of contemporary fishing patterns. We show how neglecting these key components of the marine ecosystem will almost certainly impact how CEMP indices can be related back to the processes they were originally designed to detect. Finally, we offer commentary on potential reasons why CEMP has failed to evolve over the preceding three decades, and present recent scientific work developing cost effective and modern monitoring approaches that may help improve CEMP relevance and make it fit-for-purpose.

502

DueSouth & Polardex: Enhancing Collaborative Fieldwork in the Southern Ocean & Polar Regions

Dr Julia Bach¹, Alyce Hancock¹, Griffith Couser², Renuka Badhe²

¹Southern Ocean Observing System (SOOS) hosted by IMAS/UTAS, Hobart, Australia. ²European Polar Board (EPB), The Hague, Netherlands

Abstract

Polar research necessitates efficient collaboration and logistical support. DueSouth, hosted by the European Polar Board’s infrastructure and logistics planning and discovery tool, Polardex, facilitates collaboration by connecting researchers with potential collaborators and sharing field plans. It enables researchers to find partners for data collection expeditions in the Southern Ocean and polar research stations.

DueSouth serves as a vital tool for aligning polar field campaigns reaching "beyond the borders" of traditional boundaries. Through DueSouth, scientists can identify who is going where, when, and what activities they will undertake, fostering interdisciplinary collaboration across geo, physical, and biological sciences. By providing a platform to share upcoming field plans, DueSouth contributes to shaping future initiatives and addressing the comprehensive challenges inherent in polar field campaigns.

This abstract highlights DueSouth's role in advancing fieldwork efficiency, minimizing environmental impact, and maximizing scientific outcomes, in line with the session's aim to cultivate collaboration and innovation in large-scale international initiatives.

The platform is freely accessible to all at https://polardex.org/due-south.

Uncaptioned visual

503

Crabeater seals post sea-ice maximum on the Western Antarctic Peninsula – insights gained from leveraging both aerial and satellite surveys.

Dr Connor Bamford¹, Dr Peter Fretwell¹, Dr Dan Costa², Dr Jaume Forcada¹, Dr Michael Tift³, Dr Luis Huckstadt⁴

¹British Antarctic Survey, Cambridge, United Kingdom. ²University College Santa Cruz, Santa Cruz, USA. ³University North Carolina Wilmington, Wilmington, USA. ⁴University of Exeter, Falmouth, Cornwall, United Kingdom

Abstract

Crabeater seals (Lobodon carcinophaga) are the most abundant seal species on the Western Antarctic Peninsula, with over 1.8 million individuals. Despite their namesake, they rely on krill for more than 88% of their diet, making them significant krill consumers in the Southern Ocean. Crabeater seals serve as ecosystem sentinels, with their distribution reflecting krill population changes. As with much of this ecosystem, their populations are inextricably linked to the ebb and flow of the seasonal sea ice. Since 1978, the sea ice maximum grew annually until a peak in 2014. Subsequent years have seen dramatic reductions, with 2023 marking the lowest sea ice year on record, indicating a potential new ecosystem state, typified by reduced sea ice. Yet the impact of these changes on crabeater seals remains unstudied.

Year-round habitation within the pack-ice makes data collection challenging. This has led to a deficit on this species’ population status. Here we outline preliminary findings from a joint USA and UK project, which aims to produce regional density and abundance estimates for crabeater seals. We leverage data form both aerial surveys flown in 2015 and 2023, alongside Very-High-Resolution (VHR) satellite imagery surveys spanning 2020 to 2023. We use both manual observations and automated procedures from a re-trained version SealNet 2.0, a composite machine learning model designed to identify pack-ice seals, to estimate abundance. Initial results of the 2023 aerial survey analysed, suggest that observed crabeater seal density (1.07 per km²) is half of what was observed in 2015 (2.14 per km²). Worryingly, these estimates are also lower, by an order of magnitude, than what was modelled for the Western Antarctic Peninsula two decades ago (10.9 per km²). With these surveys, we offer both temporal and latitudinal insights into how crabeater seal populations have changed over this period of decreasing sea ice.

506

Recent changes in Antarctic sea ice cover from 2016 to 2023 using satellite observations, Argo floats, and model reanalysis

Ms. Kshitija Suryawanshi^1,2, Dr. Babula Jena¹, Dr. Bajish C.C.³

¹National Centre for Polar and Ocean Research, Ministry of Earth Sciences (Govt. of India), Vasco-Da-Gama, Goa, India. ²Department of Marine Geology, Mangalore University, Mangalore, India. ³Institute of Climate Change Studies, Kottayam, India

Abstract

The sea ice cover is used as one of the indicators of polar environmental change affecting the albedo, ocean-atmosphere exchange of carbon, ocean-atmosphere circulation, ecosystems within the cryosphere. The Antarctic sea ice extent (SIE) has been steadily declining since the spring 2016, as opposed to consistent growth (1.95% decade^-1from 1979 to 2015) in the satellite era. The SIE has reached record lows in 2017, 2022, and 2023. From spring 2016, the satellite-based SIE remained consistently lower than the long-term mean, with the trend dropping to 0.42% decade^-1 from 1979 to 2023. Recently, the SIE dropped to a record low in January 2023, February 2023, and from May-October 2023 which were 11 to 40% below the long-term mean value. The present analysis reveals that the observed decrease in SIE from 2016 to 2023 resulted from a combination of factors, including the intensification of atmospheric zonal waves linked to ENSO event variability, increased poleward transport of warm-moist air, and anomalous warming in the Southern Ocean. While the decrease in sea ice in spring 2016 occurred corresponding to the transitional climate shift from IPO- (Interdecadal Pacific Oscillation, 2000-2014) to IPO+ (2014-2016), the decline after 2016 occurred in a dominant IPO- and Southern Annular Mode (SAM+). Our research using various coupled model intercomparison project phase-6 models showed a consistent decrease in ensemble-mean SIE from 1979 to 2023. The model trend closely resembles the recent decreasing trend in SIE from satellite observations since 2016, indicating a potential shift towards warmer climatic conditions.

516

Zoobenthic fauna distribution in an Antarctic fjord area under glacier retreat

Dr. Camila Neder^1,2, Dr. Kestin Jerosch³, Hendrik Pehlke³, Dr. Luciana Torre^1,2, Dr. Ricardo Sahade^1,2

Abstract

The West Antarctic Peninsula faces a significant increase in temperature and anthropogenic carbon emissions, affecting its marine and terrestrial biodiversity. Species Distribution Models (SDMs) are essential tools for assessing habitat suitability and predicting the responses to these changing conditions. In the coastal fjord ecosystem Potter Cove, glacier retreat exposed new ice-free areas altering the environment through meltwater input and sediment runoff. This research aims to predict the actual distribution of Antarctic zoobenthos in this changing coastal ecosystem and to analyze potential zoobenthic assemblage compositions in areas strongly affected by glacier retreat. Analysis of eight benthic taxa distributions reveals distinct habitat types within a maximum area range of approximately 1.5 km in length. About 60% of the study area (equivalent to 5.45 km²) is estimated to be suitable for zoobenthic occurrence. Interpretation of binary transformation thresholds reveals taxa-specific environmental preferences, wherein lower threshold values indicate broader habitat extensions. This suggests potential coexistence in glacier-influenced areas. This study emphasizes the significance of interdisciplinary approaches in understanding benthic responses to environmental shifts resulting from climate change in the Antarctic coastal ecosystem. It highlights the necessity for ongoing long-term research and the development of conservation and management strategies to address the continuing environmental shifts effectively.

520

Measuring and modeling functional moat area in perennially ice-covered Lake Fryxell, Antarctica

Michael Stone¹, Dr Mark Salvatore², Dr Hilary Dugan³, Madeline Myers⁴, Dr Peter Doran¹

¹Louisiana State University, Baton Rouge, USA. ²Northern Arizona University, Flagstaff, USA. ³University of Wisconsin - Madison, Madison, USA. ⁴Queen's University, Kingston, Canada

Abstract

The perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica are an important reservoir of liquid water in an arid and largely frozen environment. During the austral summer, the grounded margins of the lake-ice covers melt from the bottom up, forming a “moat” of thinned ice and liquid water around the lake edges. Moats serve as an interface between lake, soil, and stream ecosystems. Regions where liquid moat waters breach the surface or are covered by a transparent skin of ice are called functional moats. Functional moat area varies from year to year, causing annual changes in light availability for moat communities. Functional moat area may also affect the rate of exchanges between the lake waters and the atmosphere, the influence of wind-driven mixing in the moats, and may help control lake edge evaporation rates. To better understand this annual variation, we establish a record of annual functional moat area change for Lake Fryxell in Taylor dry valley. Using multiple satellite images, we manually measure, and also test semi-automated approaches for estimating, Lake Fryxell’s functional moat area. The manual measurements show functional moat area varying annually between ~3 and ~13% of the total lake area in images captured during January and February. The semi-automated approaches consistently underestimate the manual record by ~2% relative to the total lake area. This may be due to differences between the spatial resolution of images analyzed in the various methods. Using the manual record, we develop an index model based on readily available climate data that allows functional moat area to be predicted beyond the limits of our satellite-based record.

521

Reduced resistance to invasive herbivores in Antarctic Deschampsia antactica

Professor Kari Saikkonen

University of Turku, Turku, Finland

Abstract

Climate change is predicted to facilitate polewards shifts of species geographic ranges and thereby shape native biodiversity and ecosystem functions in Polar regions. Currently the Antarctic hosts only two endemic vascular plant species, Deschampsia antarctica and Colobanthus quitensis. The species were distributed from Patagonia to western Antarctic Peninsula in the Holocene or Late Pleistocene. Since then the Antarctic populations have evolved in virtually herbivore-free space compared to their Patagonian ancestors.

We tested if D. antactica plants collected from Patagonia and Antarctica differ in their resistance to a generalist herbivore, the bird cherry oat aphid (Rhopalosiphum padi). The field-collected plants were grown in a greenhouse at the Botanic garden of University of Turku, Finland, in 2022 and 2023. In the well replicated experiment, 64 plants in total were placed in four aphid treatment and control insect rearing cages to test aphid preference and plant tolerance to herbivory. Four weeks later plants were harvested and frozen, aphids were counted, and the number of tillers and dry mass of plants were recorded. Aphids clearly preferred the Antarctic to Patagonian plants (p = 0.028) and the damage of Antarctic plants tended to be stronger compared to Patagonian ones (p = 0.055). The survival and growth of the Antarctic and Patagonian plants did not differ in the absence of the aphids.

These results revealed the reduced resistance of D. antactica to herbivores during the colonization history of the species in Antarctica, and suggest that the Antarctic genotypes may become extinct within their current ranges as a result of climate change and the invading species. Invading herbivores can consume endemic D. antactica plants, and Patagonian genotypes and novel plant species with higher resistance to herbivores can hybridize or outcompete endemic D. antactica.

525

Quantifying the value of Antarctic polynyas on the ecosystem from phytoplankton to penguins

Dr. Alice DuVivier¹, Dr. Kristen Krumhardt¹, Dr. Laura Landrum¹, Zephyr Sylvester², Dr. Marika Holland¹, Dr. Stephanie Jenouvrier³, Dr. Bilgecan Sen³, Dr. Francesco Ventura³, Dr. Christian Che-Castaldo⁴, Dr. Sara Labrousse⁵, Marthe Vienne⁵, Lucie Bourreau⁵, Dr. Michelle LaRue⁶, Dr. Cassandra Brooks²

¹NSF NCAR, Boulder, USA. ²University of Colorado Boulder, Boulder, USA. ³Woods Hole Oceanographic Institute, Falmouth, USA. ⁴Stony Brook University, Stony Brook, USA. ⁵L'OCEAN, Paris, France. ⁶University of Canterbury, Christchurch, New Zealand

Abstract

The Southern Ocean is one of the fastest changing regions on the planet and an emerging resource frontier for fisheries. In polar regions, coastal polynyas – open water areas along the coast bordered high regions with higher sea ice concentration – are “hot spots” of high biological productivity, yet polynyas remain both unprotected and understudied. Antarctic polynyas are locations of high primary productivity and frequent use by upper trophic predators throughout the year. This work seeks to understand the ecological importance of small-scale polynyas across trophic levels, and how this may change over time with the changing climate. To better quantify the ecological value of polynya regions, we present a novel synthesis that integrates satellite sea ice observations, data from Earth system model projections of phytoplankton productivity, krill growth, and fish biomass in tandem with habitat usage by southern elephant seals and demographic projections of emperor penguin and Adelie penguin populations. We find that primary and secondary production is elevated in polynya regions compared to the overall seasonal sea ice zone, and polynya areas are frequently visited by southern elephant seals. Previous work has found that distance to polynyas can be important for emperor and Adelie penguin colony size. In our analysis, we incorporate the number of penguins from demographic projections, that can access nearby polynyas. We merge these findings to a quantifiable metric that can be used to inform Southern Ocean conservation, including the development of marine protected areas.

527

A comprehensive study of the life history traits of Trematomus newnesi (Pisces, Notothenioidei) from the South Shetland Islands

Dr. Manuel Novillo^1,2, Dr. Eugenia Moreira^1,3,4, Dr. Mariano Elisio^1,5,6, Dr. Gustavo Macchi^1,5,6, Dr. Esteban Barrera-Oro^1,7, Dr. Mario La Mesa⁸

¹Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ²Instituto de Diversidad y Ecología Animal (IDEA-CONICET), Córdoba, Argentina. ³Instituto Antártico Argentino (IAA), Buenos Aires, Argentina. ⁴Laboratorio de Biología Funcional y Biotecnología (BIOLAB) - UNCPBA-CICBA - INBIOTEC-CONICET, Azul, Buenos Aires, Argentina. ⁵Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Mar del Plata, Argentina. ⁶Instituto de Investigaciones Marinas y Costeras (IIMyC), Mar del Plata, Argentina. ⁷Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN), Buenos Aires, Argentina. ⁸National Research Council (CNR), Institute of Polar Sciences (ISP), Bologna, Italy

Abstract

Understanding the life history traits of Antarctic fish species is crucial for effective management and conservation efforts purposes. This study provides a comprehensive evaluation of the reproductive dynamics and age-growth characteristics in Trematomus newnesi, a common notothenioid species in the High-Antarctic zone. Field observations conducted in Potter Cove, South Shetland Islands, revealed significant variations in photoperiod and water temperature from November to March, with water temperatures reaching a peak in mid-December. Gonadal morphology showed an exponential increase in gonadosomatic index in females and males from November to March, indicating ovarian and testicular development. Sex steroid plasma levels, particularly testosterone (T) and estradiol (E₂), showed significant variations, with elevated levels observed during late vitellogenesis, suggesting the proximity of final maturation and spawning. Age estimation through otolith readings provided a range of ages up to five years old for both sexes. Comparison with previous studies on T. newnesi from other Antarctic areas highlighted similarities and differences in reproductive patterns and growth parameters, respectively. Our study suggests that temperature fluctuations, in conjunction with photoperiod, may act as triggers for reproductive events in T. newnesi starting in early autumn at Potter Cove. The environmental cues and reproductive data indicate that Potter Cove might serve as a spawning ground for T. newnesi. Likewise, larval hatching was estimated to occur from early to mid-August, suggesting an egg incubation period of four months. Overall, this study provides insights into the reproductive dynamics and life history traits of T. newnesi, as a valuable contribution for appropriate management and conservation of Antarctic fish populations.

528

Unveiling the Riches of the Frozen South: The SCAR Antarctic Biodiversity Portal

Dr. Anton Van de Putte^1,2, Ms. Yi-Ming Gan¹, Mr Charlie Plasman¹

¹Royal Belgian Institute of Natural Sciences, Brussels, Belgium. ²Université Libre de Bruxelles, Brussels, Belgium

Abstract

The Antarctic region's extensive and varied ecosystems provide valuable knowledge on life in harsh conditions. However, scattered and often inaccessible data present a challenge for researchers, policymakers, and the public. The SCAR Antarctic Biodiversity Portal (biodiversity.aq) supports this by providing a centralised platform for publishing, discovering, accessing, and using Antarctic biodiversity data.

Biodiversity.aq provides extensive access to marine and terrestrial biodiversity information. Users get access to more than 6.6 million instances from different data suppliers, which include information on species distribution, abundance, and environmental factors published in line with the FAIR principles.

The portal empowers researchers by offering advanced search functionalities, the ability to download data in standardised forms that comply with international standards such as Daawincore, and an inventory of online tools for data publication, cleaning and analysis. Additionally, identification keys and links to external databases further enrich the user experience.

Biodiversity.aq is an important resource for conservation and management initiatives, in addition to its research function. The portal facilitates informed decision-making by offering crucial information about the distribution and status of Antarctic species.

The SCAR Antarctic Biodiversity Portal promotes worldwide collaboration, scientific discovery, and sustainable management of the unique Antarctic ecosystem by providing free and open access to biodiversity data compliant with the FAIR, CARE and TRUST principles.

531

Weddell Sea Observatory of Biodiversity and Ecosystem Change - WOBEC - An international collaborative effort

Dr. Anton Van de Putte^1,2, Dr. Karley Campbell³, Ms. Claire Christian⁴, Dr. Hauke Flores⁵, Dr. Heike Link⁶, Dr Sebastien Moreau⁷, Susa Niiranen⁸, Prof. Chiara Papetti⁹, Dr. Fokje Schaafsma¹⁰, Prof Jacqueline Stefels¹¹, Dr Józef Wiktor¹²

¹Royal Belgian Institute of Natural Sciences, Brussels, Belgium. ²Université Libre de Bruxelles, Brussels, Belgium. ³UiT The Arctic University of Norway, Tromsø, Norway. ⁴Antarctic and Southern Ocean Coalition, Washington, DC, USA. ⁵Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany. ⁶UNIVERSITAET ROSTOCK, Rostock, Germany. ⁷NORSK POLARINSTITUTT, Tromsø, Norway. ⁸Stockholm University, Stockholm, Sweden. ⁹University of Padova, Padova, Italy. ¹⁰Wageningen Marine Research, Den Helder, Netherlands. ¹¹Rijksuniversiteit Groningen, Groningen, Netherlands. ¹²Institute of Oceanology Polish Academy of Sciences, Gdansk, Poland

Abstract

The Eastern Weddell Sea (EWS) is a vulnerable habitat that is greatly affected by climate change, impacting its physical characteristics, biodiversity, and ecosystem operations. The distinct variety of biodiversity and ecosystems in Southern Ocean habitats is under serious threat from climatic scenarios outlined by the Intergovernmental Panel on climate Change (IPCC), which have worldwide impacts on the well-being of humans and economics. The EWS may be on the verge of shifting from a period of relative stability to a new phase characterised by a decline of sea ice. The Weddell Gyre displays indications of ocean acidification, freshening, and changes in nutrient levels.

Regular monitoring of the EWS ecosystem is necessary in order to determine the baseline of current status of biodiversity and ecosystem functioning, enabling stakeholders to implement suitable protection and mitigation strategies. It is crucial for the timely execution of the Weddell Sea Marine Protected Area (WSMPA), which is considered for establishment by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).

Here, we present the Biodiversa+ Project Weddell Sea Observatory of Biodiversity and Ecosystem Change (WOBEC). The objective is to create a proficient monitoring framework to assess change and differentiate trends from natural variability in the EWS. WOBEC will advance multiscale biodiversity monitoring by integrating modern technology and computational advancement into a common framework of observation parameters, protocols, and sampling schemes. It will also contribute to harmonising monitoring standards globally and identify new goals for polar research.

535

Non-Invasive Surveillance and Evolutionary Insight into Siadenovirus among Antarctic Penguins

BSc. Irene Ferreiro^1,2, MSc. Rodrigo Arce^1,2, MSc. Joaquín Hurtado^1,2, MSc. Fabián Aldunate^1,2, MSc. Paula Perbolianachis^1,2, MSc. Diego Simón^1,2, PhD. Gonzalo Moratorio^1,2,3, PhD. Pilar Moreno^1,2,3, PhD. Juan Cristina¹

¹Laboratorio de Virología Molecular, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Laboratorio de Evolución Experimental de Virus, Institut Pasteur de Montevideo, Montevideo, Uruguay. ³Centro de Innovación en Vigilancia Epidemiológica, Institut Pasteur Montevideo, Montevideo, Uruguay

Abstract

Avian siadenoviruses infect diverse terrestrial and aquatic birds worldwide. Antarctica hosts several avian species that are susceptible to siadenovirus infection, such as penguins and South Polar skuas. However, the presence, diversity and transmission of these viruses in Antarctic birds are poorly understood due to limited surveillance and sequence data. In this study, we performed a non-invasive surveillance of avian siadenoviruses using fecal samples collected from waterbirds at King George Island (part of the South Shetland Islands, Antarctica) from late January to mid-February 2023. PCR, sequencing, and phylogenetic analysis were used to investigate the occurrence, genetic diversity, and evolutionary relationships of these viruses in this unique environment. The results of these studies confirmed the presence of siadenoviruses in penguins living along the southeastern coast of King George Island. Distinct viral strains, specific to each penguin species studied were found, suggesting limited interspecies transmission and a complex viral ecosystem within Antarctic bird populations. This study is the first to non-invasively detect siadenoviruses in Antarctic penguins, opening a new avenue for viral research. This approach not only sheds light on viral dynamics, but also contributes to the conservation of Antarctica's unique wildlife and biodiversity, especially in the face of increasing global warming.

538

The earliest glacial communities from the Cenozoic of Antarctica

Dr Rowan Whittle¹, Professor John Smellie², Dr Fernanda Quaglio³, Dr Anne Flink¹, Dr Alex Burton-Johnson¹

¹British Antarctic Survey, CAMBRIDGE, United Kingdom. ²University of Leicester, Leicester, United Kingdom. ³Universidade Federal de São Paulo, Sao Paulo, Brazil

Abstract

The sea floor (benthic realm) is the most biodiverse part of the modern-day Southern Ocean. It is unique compared to the rest of the world, being dominated by immobile suspension-feeding creatures. Benthic communities elsewhere normally have large numbers of burrowing organisms, and mobile predators and prey. Many Antarctic benthic organisms are stationary; therefore, they are vulnerable to activities such as fishing and the invasion of predatory groups due to climate change or human introduction. How the biodiversity and stability of modern Southern Ocean benthic ecosystems is maintained today is unknown. We are studying the evolution of Southern Ocean communities to identify the conditions under which they evolved and give an indication of environmental conditions which are necessary for their maintenance. In Antarctica, the earliest known Cenozoic glacial communities are from Oligocene deposits of the King George Island (northwest tip of Antarctic Peninsula 61.9°S). The geological formations on this island provide a unique window into Southern Ocean glacial sea floor communities ~ 26 Ma. Glacial evidence comes from the presence of dropstones, striated rocks, and diamictites. Communities are dominated by epifaunal suspension feeding organisms. Pectenid bivalves and brachiopods occur in large aggregations in shallow water deposits. There are very few predatory groups preserved. This research forms part of a larger effort to document community change under different temperature regimes through the Cenozoic in order to understand the evolution of modern Antarctic communities. This will increase ability to predict the effects of anthropogenic climate change on these unique communities.

542

Nexus and fulcrum: an exploration of the role of poetry and the poetry workshop in polar science communication

Dr Elizabeth Lewis Williams¹, Dr Jennifer Freer²

¹University of East Anglia, Norwich, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom

Abstract

Humphrey Davy, the electrochemical pioneer who identified elements of the periodic table, wrote poetry, sometimes even in the laboratory; Percy Bysshe Shelley, the Romantic poet who penned ‘Ode to the West Wind,’ used to conduct chemical experiments in his study. The perceived separation of poetry and science is comparatively recent and artificial. Both disciplines rely on close observation and precise expression to develop and convey understanding. They also both require the application of different types of measure: mathematical, rhythmic, relational. Looking at particular poems by poets writing about Antarctic science, this presentation will consider how different poetic forms might open up ways of thinking which allow for embodied responses to the research subject; the way haiku requires a distillation of complex ideas into concrete images, for example, or how a ‘poetry of fact’ can contain both empirical observation and emotion.

This presentation will build on previous work by science communicators such as Sam Illingworth and Gregory Johnson to demonstrate the capacity of poetry, and of the poetry workshop, to enable creative responses to research, to promote dialogue and wellbeing, and to develop resources. Creating poetry requires active engagement with the subject. We will consider the workshop as a meeting place or pivot point, where people with different backgrounds can come together to write poetry, and from which both poems and process can be employed in future science communication. The presentation will include reflections by the ecologist Jen Freer on her experience of participating in poetry workshops, both at the British Antarctic Survey and as part of the science network JETZON. It will also look at some examples of poetry communication projects, such as Project Communication Haiku and the SciBards. The presentation will end with a reading of poems that have emerged from workshop participants.

544

Challenges, needs and proposed solutions for better supporting everyone in our polar early career researcher community

Mariama C. Dryák-Vallies^1,2, Anne U. Gold², Bradley Markle³

¹Polar Science Early Career Community Office, Boulder, CO, USA. ²Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA. ³Institute of Arctic and Alpine Research, Department of Geological Sciences, University of Colorado Boulder, Boulder, CO, USA

Abstract

The polar regions are experiencing rapid, dramatic impacts due to climate change that require innovative and transdisciplinary solutions, which in turn require a well-supported and connected interdisciplinary community of scientists. The Polar Science Early Career Community Office (PSECCO) aims to foster exactly such a diverse, international, and multidisciplinary network of scientists early in their careers. Over the past two years PSECCO has asked early career researchers (ECRs) what they view as challenges, issues and gaps in support relevant to ECRs. We found that challenges to polar ECRs can be broken down into three main categories: 1) challenges in making and sustaining connections within and across the polar community; 2) challenges in accessing resources and trainings relevant to ECR growth; 3) a need for cultural change across the polar sciences to build welcoming and accessible community spaces. Here, we discuss some of what is and is not being addressed of those issues within the polar sciences, and present potential solutions to those challenges that can be spearheaded by members of the community. We investigate the potential benefit of using ‘Collective Impact’ and ‘Community of Practice’ frameworks to do this work. The Collective Impact framework is an exercise of bringing people together from across polar science disciplines and positionalities to achieve social change in a structured way and ‘Communities of Practice’ would entail bringing polar scientists together regularly who are working towards a common goal to learn alongside one another in creating welcoming and inclusive polar science community spaces for all. With these proposed solutions and practices in mind, people individually within their institutions and community organizations like the PSECCO, can and do play an important role in bolstering the polar ECR community, ultimately enhancing their contributions to polar science to help work towards solutions to the global climate crisis.

548

Counterspace capabilities within the Antarctic Treaty System: Uncovering the emerging hazard from space technologies for the principle of peaceful uses of Antarctic territory and its governance.

Mg. Victoria Valdivia

ESPI, Santiago, Chile

Abstract

The development of technologies associated with the exploration and utilization of outer space has rapidly evolved, giving rise to new dual-use technologies critical for the safety of space-based missions. This development represents a significant factor in the geopolitical dynamics of the international system. Given its natural characteristics and proximity to polar orbits, the Antarctic territory has become an ideal location for the deployment of these novel capabilities, many of which fall under the category of "counterspace capabilities," challenging the principles of the Antarctic Treaty System (ATS), particularly its ban on the placement of any weapons within the continent.

Emerging evidence suggests that as incentives for space conflict increase, there is a high probability of observing the deployment of such capabilities in Antarctic operations and activities in the near future, thereby challenging international principles and governance in Antarctica.

This research addresses the gray areas between the ATS and the Outer Space Treaty concerning dual-use technologies such as outer space capabilities. The hypothesis of this study is that these gray areas contribute to the emerging hazards associated with outer space interstate conflicts, potentially extending them to Antarctic operations. Using a method of comparative case analysis, this exploratory research will delve into counterspace capabilities in Antarctica, providing valuable guidelines to prevent the militarization of space in Antarctica and contribute to reinforcing the peaceful uses of the continent.

Due to its novelty, this research will contribute to the academic understanding of Antarctic phenomena and frontier research, offering new perspectives on the challenges facing the future governance of Antarctica.

550

Assessing Antarctic Marine Biodiversity and Invasive Species Using eDNA Metabarcoding

Dr. Carla Ximena Salinas¹, Dr. Sook-Young Lee², Dr. Sung Mi Cho², Dr. Seunghyun Kang², Dr. Sanghee Kim²

¹Instituto Antártico Chileno, Punta Arenas, Chile. ²Korea Polar Research Institute, Incheon, Korea, Republic of

Abstract

The use of eDNA metabarcoding has been shown to be a successful approach in accurately capturing the diversity of marine ecosystems. In this context, the objectives of this study are to assess the biodiversity of marine organisms in an Antarctic Specially Protected Area located in South Bay, Doumer Island, using eDNA techniques, and to evaluate the use of this technique for monitoring potential invasive species. Seawater samples were taken aboard a pneumatic boat at four sampling stations near the Chilean Antarctic scientific base Yelcho (64.9° S, 63.6° W). Subsequently, they were filtered, prepared, and DNA was extracted in the laboratory. The results of this study expand the record of Antarctic marine species for South Bay, identifying new species. Regarding potentially invasive species, this study has detected several non-Antarctic species in South Bay. Our results suggest that the eDNA technique is an effective method of assessing marine biodiversity and invasive species in Antarctica. However, eDNA still presents some weaknesses that need to be considered. Reference DNA databases for Antarctic species are incomplete, which hinders the accurate identification of species from their eDNA. Therefore, more research is needed to strengthen the databases and thus to improve taxonomic descriptions. We conclude that eDNA is a valuable tool to assess and monitor biodiversity in Antarctica, particularly in the Antarctic Specially Protected Areas, and for the monitoring of potentially invasive species.

561

How the weather may have affected the fate of Shackleton's Endurance

Dr Ryan Fogt¹, Ms. Ashlee Ziegler¹, Dr. John King², Dr. Julie Jones³

¹Ohio University, Athens, USA. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Sheffield, Sheffield, United Kingdom

Abstract

The sinking of the Endurance in the Weddell Sea led by Ernest Shackleton presented one of the most well-known cases of survival and heroism throughout all of Antarctic history. The ship entered the Antarctic region in early summer 1914, and soon became stuck in the Weddell Sea sea ice. Unfortunately, the ship was never freed from the ice, and eventually was crushed and sank to the bottom. It was recently discovered on the bottom of the Weddell Sea in 2022.

While the story has been told of the survival of the crew and the heroic voyage across the Drake Passage in a small lifeboat, the role of the weather leading to this dramatic outcome has been less investigated, especially in a longer-term historical context. In this talk, we will pair together information from nearby stations, reconstructions of Antarctic sea ice and pressure, and contemporary reanalyses to understand what role the weather in 1914-1915 in this region may have played in the trapping and eventual destruction of the Endurance. These longer climate histories will be compared to the detailed meteorological measurements made on or near (after it was no longer safe to stay on board) the Endurance for a new retelling of an age-old tale.

570

Calving glaciers in Patagonia and the Antarctic Peninsula; common problems and future research strategies

Dr Andres Rivera¹, Dra Maria Gabriela Lenzano², Dr Esteban Lannutti^2,3, Dr Luis Lenzano⁴, Dr Michal Petlicki^5,6

¹Department of Geography, University of Chile, Santiago, Chile. ²Geomatics Andean Lab, Argentine Institute of Nivology, Glaciology and Environmental Sciences (IANIGLA)-CONICET, Mendoza, Argentina. ³National Technological University, Mendoza Regional Faculty, Mendoza, Argentina. ⁴International Center of Earth Sciences, UNCuyo, Mendoza, Argentina. ⁵Department of Geography, Universidad de Concepcion, Concepcion, Chile. ⁶Jagiellonian University, Krakow, Poland

Abstract

After Antarctica, the Patagonia Icefields (PI) are the largest ice mass in Southern Hemisphere. The main glaciers of the PI are calving into fjords or lakes, where local topography (especially the bathymetry), is playing an important role controlling glacier dynamics accelerating glacier retreats. Many of the Antarctic Peninsula glaciers are also calving into fjords and experiencing, in many cases, strong retreats. The glaciers in both regions share some characteristics, since they have very high snow accumulation rates, and in general, well-defined ice basins with a surrounding rugged topographies determining ice flows. In some other cases, the Peninsula’s glaciers are sharing a plateau similar to the biggest glaciers in the PI that are flowing from flat high altitude areas. Among the main differences between both regions are melting and ice velocities, both much higher in the PI. However, in response to climatic changes, especially the ongoing warming trends in the Peninsula, glacier melting is expected to increase. Modelling future glacier responses needs a much strong research especially nearby glacier fronts including bathymetric, dynamics and oceanographic/limnological studies. In recent years we have researched the ice-lake/fjords interactions in several Patagonian glaciers, including the western calving glaciers of the Northern Icefield, several freshwater calving glaciers in the eastern margin of Southern Patagonia Icefield and tidewater calving glaciers in Cordillera Darwin. Here we will present some of our results in Patagonia compared to changes experienced by calving glaciers in King George Island and the Antarctic Peninsula. The bathymetric data in front of the Peninsula’s glaciers are much more restricted than in Patagonia, but among the compared glaciers we have found a similar dependency on local bathymetries. Much more in situ data are needed for addressing the future evolution of these glaciers. A robust research strategy will be proposed for addressing these scientific problems.

574

Origin of increasing soil gas carbon emissions in Taylor Valley, Antarctica

Prof Gary Wilson^1,2, Dr Livio Ruggiero^3,4, Dr Valentina Romano⁴, Dr Alessandra Sciarra⁴, Dr Fabio Florindo⁴, Dr Adriano Mazzini⁵, Dr Jacob Anderson⁶, Mr Massimiliano Ascanti⁴, Mr Jackson Beagley⁶, Prof Sabina Bigi⁷, Mr Thomas Brakenrig⁸, Dr Giancarlo Ciatoli⁹, Mr Robert Dagg⁶, Ms Lucy Davidson⁶, Dr Federico Fischanger¹⁰, Dr Richard Hardie¹¹, Dr Graham Leonard², Prof Claudio Mazzoli¹², Prof Valerio Olivetti¹², Prof Raffaele Sassi¹², Dr Maria Chiara Tartarello⁷, Ms Rachel Worthington⁶

¹University of Waikato, Hamilton, New Zealand. ²GNS Science, Wellington, New Zealand. ³Italian Institute for Environmental Protection and Research, Rome, Italy. ⁴National Institute of Geophysics and Volcanicology, Rome, Italy. ⁵University of Oslo, Oslo, Norway. ⁶University of Otago, Dunedin, New Zealand. ⁷Sapienza University of Rome, Rome, Italy. ⁸GNS Science, Wairakei, New Zealand. ⁹Institute of Environmental Geology and Geoengineering, Rome, Italy. ¹⁰Geostufi Astier S.r.l., Livorno, Italy. ¹¹Department of Internal Affairs, Wellington, New Zealand. ¹²University of Padua, Padua, Italy

Abstract

Contemporary studies conducted in northern polar regions reveal that permafrost stability plays an important role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emission, both from physical and microbiological processes. The potential impact of greenhouse gas release from Antarctica is now also being investigated. In Antarctica, the McMurdo Dry Valleys comprise 10% of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit from lower mean temperatures. Here we present the combined results of extensive soil gas analyses, shallow electrical resistivity, and deep electrical resistivity tomography surveys. Analytical results reveal the presence of significant concentrations of CH₄, CO₂ and He (up to 18,447 ppmv, 34,400 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increasing CO₂ flux rates (estimated CO₂ emission in the study area of 21.6 km² ≈ 15 tons day^-1). Resistivity data identify a 50-100m thick highly resistive surface layer across the valley underlain by conductive layers between 50-100 m, 300-350 m and 600-650 m in-turn separated by resistive layers. The combined dataset reveals a broad brine system in Taylor Valley, implying multi-tiered groundwater circulation separated by frozen ground. The distribution of the gas anomaly, when compared with geophysical investigations, implies the gas originates from the deeper brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These newly obtained data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emission from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms.

575

Antarctica: all to lose

Ms Lea Kannar-Lichtenberger

JLL Foundation - Studios, Sydney, Australia

Abstract

This paper will explore the artist's role in creating awareness about the human impact on and in Antarctica. Interdisciplinary artist Lea Kannar-Lichtenberger will examine how the dissemination of her Antarctic research and creative art practice has impacted her audiences around Australia. Through various media that use (but are not limited to) thermal imaging, sound, ice installations, photography, drawing and poetry, she will examine the artist's role in the discourse of environmental protection.

As an artist/traveller/observer, Kannar-Lichtenberger utilises her past (2017) and more recent (2023) self-funded Antarctic research expeditions to consider the visitor's engagement with the fragility of Antarctica. Antarctica: all to lose will explore how her series of solo exhibitions across Australia (2017-2023) has engaged and impacted audiences.

Kannar-Lichtenberger will delve into the audience's response to the various media exhibited, individually and as a whole. Through an analysis of published reviews, onsite public engagements, and audience reaction, she will examine this exhibition series to create a broad understanding of the resulting viewer impact. This examination will be invaluable for the creation of future artworks to increase public engagement with a view to influencing travel behaviour.

576

Ice elevation changes in the interior of the West Antarctic Ice Sheet by comparing in situ GPS and remotely sensed LiDAR data

Dr Andres Rivera¹, Dra Maria Gabriela Lenzano², Dra Paulina Vecaflor², Dr Luis Lenzano³, Mr Jorge Hernandez⁴, Dr Felipe Napoleoni⁵, Dr Ricardo Jaña⁶, Dr Jorge Arigony⁷

¹Department of Geography, Universidad de Chile, Santiago, Chile. ²Geomatics Andean Lab, Argentine Institute of Nivology, Glaciology and Environmental Sciences (IANIGLA)-CONICET, Mendoza, Argentina. ³International Center of Earth Sciences, UNCuyo, Mendoza, Argentina. ⁴Instituto Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, Chile. ⁵University of Edinburgh, Edinburgh, United Kingdom. ⁶Instituto Antartico Chileno, INACH, Punta Arenas, Chile. ⁷Universidad Federal do Rio Grande, Porto Alegre, Brazil

Abstract

The ice divide between the glaciers flowing to the Amundsen Sea Embayment Area, considered the most vulnerable region of Antarctica, and those flowing to the Weddell Sea, has been subject of numerous geophysical surveys carried out in recent decades along oversnow traverses, discovering a complex subglacial topography and hydrology with some subglacial lakes. During these field campaigns dating from 2006 to 2017, an extended network of GPS measurements were obtained, showing a smooth and relatively flat surface topography, except along the valleys connecting the high plateau where the ice divide is located, and the outflow glaciers such as Union or Minnesota. At the high plateau several mass balance parameters were also observed including snow accumulation from stake heights, and in a couple of sites, snow/firn shallow cores. These very valuable, accurate and unique in situ data sets are compared to remotely sensed ICESat and Cryosat data, in order to obtain elevation changes. Moreover, the GPS and DGPS measurements are compared with available DEMs. In general, the study area is having very little changes with slightly positive values among the Weddell sea side and very minor negative in the Amundsen Sea Area which is consistent with the values previously estimated for example by Nilsson et al., 2022 (https://doi.org/10.5194/essd-14-3573-2022). However, our main interest is detecting local elevation changes related to possible volume variations experienced by subglacial lakes such as SLE (79ºS / 90º30'W) and SLC (79º15'S / 87º34'W). Up to now, we were not able to detect vertical changes associated to these subglacial lakes, suggesting a stable hydrological system. Apart from discussing our results, we will present a new strategy for a much and better glacier research in this region of Antarctica.

580

Discrepancies between morphological and molecular diversity in an Antarctic nematode

Abigail Borgmeier, Byron Adams

Brigham Young University, Provo, UT, USA

Abstract

Eudorylaimus is one of five nematode genera that are found in the Antarctic Dry Valleys. Despite being one of only a handful of nematode taxa present in the region, there have been a limited number of studies characterizing the diversity of Eudorylaimus in the Dry Valleys. It is possible that there is more than one species present within the Dry Valleys after examining the degree of molecular diversity within the genus in Antarctica. The first objective of this study is to examine the degree of molecular diversity within Antarctic Eudorylaimus as compared with other Eudorylaimus species within the Eudorylaimus phylogeny. The second objective of this study is to resolve the Eudorylaimus genus phylogeny to find evidence for which Eudorylaimus taxa is sister to the Antarctic Dry Valleys Eudorylaimus species. All available Eudorylaimus sequences from GenBank and the Barcode of Life Datasystems (BOLD) were downloaded. The COI mitochondrial genes, 28S genes, and the 18S small ribosomal subunit genes of any species of Eudorylaimus were downloaded and included in the dataset. Eudorylaimus specimens were collected from the McMurdo Dry Valley region and the 18S and COI loci were sequenced. Following phylogenetic analysis using maximum likelihood trees, the Antarctic Eudorylaimus clade shows that there is very low genetic diversity within Antarctic Eudorylaimus taxa, even though these taxa are from distant locations. There is a large divergence between Antarctic Eudorylaimus and all other Eudorylaimus species, making it impossible to determine the sister taxa to Antarctic Eudorylaimus without further sampling. While there is high morphologic variation within this region, there is low genetic variation within the selected loci, making it unique compared to other Antarctic nematodes with high genetic variation and population structure.

582

An unprecedented season for sea ice: a view from the ocean

Natalie Robinson^1,2, Brett Grant¹, Ollie Twigge¹, Craig Stewart¹, Greg Leonard³, Ken Ryan²

¹NIWA, Wellington, New Zealand. ²Te Herenga Waka, Wellington, New Zealand. ³University of Otago, Dunedin, New Zealand

Abstract

The 2022 Antarctic sea ice growth season was unprecedented in the satellite era, including what was, at that time, the lowest pan-Antarctic September extent on record. In McMurdo Sound the fast ice cover formed and re-formed several times until the end of August, when a stable cover was finally established – four months later than usual. This local effect was driven by a series of southerly storms that drove extreme activity of the McMurdo Sound and Ross Sea polynyas. As a result, new sea ice growth occurred locally throughout the winter, driving deep and persistent brine rejection events. ‘Blowdown’ events 2-3 times larger than in a typical year were also observed, although these were associated with temperature signals that originated near the seafloor and progressed upwards through the water column. Here we present 24 months of new ocean data from southern McMurdo Sound captured with a novel seafloor-mounted mooring, along with synchronous Argo data from the Ross Sea continental shelf. We use the atypical signals of the 2022 growing season to identify possible pathways, timescales, and mechanisms of connection between the High Salinity Shelf Water formation region of the Ross Sea Polynya and our mooring site in Haskell Strait – which is the western gateway to the Ross Ice Shelf ocean cavity.

583

RESURGENCE OF ANTHROPOGENIC INFLUENCE IN FOOD WEB DYNAMICS OF THE ROSS SEA

Dr David Ainley¹, Dr Virginia Morandini², Dr Leo Salas³, Dr Nadav Nur⁴, Dr Jay Rotella⁵, Ms Kerry Barton⁶, Dr Phil Lyver⁶, Dr Kimberly Goetz⁷, Dr Michelle LaRue⁸, Dr Rose Foster-Dyer⁸, Dr Claire Parkinson⁹, Dr Kevin Arrigo¹⁰, Dr Gert van Dijken¹⁰, Dr Roxanne Beltran¹¹, Dr Stacy Kim¹², Dr Cassandra Brooks¹³, Dr Gerald Kooyman¹⁴, Dr Paul Ponganis¹⁵, Dr Fiona Shanhun¹⁶, Dr Dean Anderson⁶

¹H.T. Harvey & Associates, Los Gatos, CA, USA. ²Fundación Migres, Cádiz, Spain. ³Point Blue Conservation Science, Petaluma, USA. ⁴Point Blue Conservation Science, Petaluma, CA, USA. ⁵Montana State University, Bozeman, MT, USA. ⁶Landcare Research NZ, Lincoln, New Zealand. ⁷National Ocean & Atmospheric Administration, Seattle, WA, USA. ⁸University of Canterbury, Christchurch, New Zealand. ⁹NASA Space Flight Center, Greenbelt, MD, USA. ¹⁰Stanford University, Stanford, CA, USA. ¹¹University of California, Santa Cruz, CA, USA. ¹²Moss Landing Marine Laboratories, Moss Landing, CA, USA. ¹³University of Colorado, Boulder, CO, USA. ¹⁴University of California, San Diego, CA, USA. ¹⁵University of California, San Deigo, CA, USA. ¹⁶Environment Canterbury, Christchurch, New Zealand

Abstract

Most of the Ross Sea has been designated a marine protected area (MPA), proposed “to protect ecosystem structure and function.” To assess effectiveness, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) selected Adélie (Pygoscelis adeliae) and emperor (Aptenodytes forsteri) penguins, Weddell seals (Leptonychotes weddellii), and Antarctic toothfish (Dissostichus mawsoni), as ecosystem change ‘indicator species.” Stable for decades, penguins and seal populations increased during 1998-2018 to surpass historical levels, indicating that change in ecosystem structure and function is underway. We review historical impacts to population trends, decadal data sets of ocean climate, and fishing pressure on toothfish. Statistical modeling for Adélie penguins and Weddell seals indicates that variability in climate factors and cumulative extraction of adult toothfish may explain these trends. These mesopredators, and adult toothfish, all prey heavily on Antarctic silverfish (Pleuragramma antarcticum). Toothfish removal may be altering intraguild predation dynamics, leading to competitive release of silverfish, and contributing to penguin and seal population changes. Despite decades of ocean/weather change, increases in indicator numbers around Ross Island only began once the toothfish fishery commenced. The rational use, ecosystem-based viewpoint promoted by CCAMLR regarding toothfish management needs re-evaluation in the context of the Ross Sea Region MPA.

584

Remote pathways of ocean heat transport toward the Antarctic Ice Sheet

Channing Prend^1,2, Graeme MacGilchrist³, Andrew Thompson²

¹University of Washington, Seattle, USA. ²California Institute of Technology, Pasadena, USA. ³University of St Andrews, St Andrews, United Kingdom

Abstract

Antarctic Ice Sheet (AIS) mass loss contributes significantly to global mean sea level rise. Therefore, understanding the mechanisms that control AIS melt rates is of critical importance to plan for the effects of climate change. Transport of warm Circumpolar Deep Water (CDW) into ice shelf cavities is known to be a primary source of heat driving AIS melt. This CDW originates in the Antarctic Circumpolar Current (ACC) and is brought onto the continental shelf by small-scale physical processes such as eddies and tidal rectification. Onshore CDW transport is not spatially uniform, however, and its regional variations are often invoked to explain the different hydrographic regimes that persist on the Antarctic continental shelf. While cross-shelf heat fluxes are certainly an important part of the story, less focus has been placed on the offshore processes that bring CDW from the ACC to the shelf break. Here, we use Lagrangian particle release experiments in an ocean model to investigate the pathways by which CDW moves toward the continental slope, which is a necessary precursor to the cross-shelf exchange that has been studied in more depth. We show that these offshore pathways may play an important role in setting the continental shelf properties. Namely, the different shelf regimes are associated with distinct timescales and degrees of modification that CDW undergoes along its route to the shelf break. This is important context through which to understand regional and temporal variations in continental shelf heat content, which in turn, has implications for basal melting of ice shelves and future sea level rise.

585

Remotely sensing a decade of change in the McMurdo Dry Valleys: Mapping spatial and temporal trends in ecosystem properties in Fryxell Basin

Eric Sokol¹, John Barrett², Michael Gooseff³, Paul Knightly⁴, Joseph Levy⁵, Sarah Power², Mark Salvatore⁴, Khum Thapa-Magar³, Morgan Wood²

¹National Ecological Observatory Network, Battelle, Boulder, USA. ²Virginia Tech, Blacksburg, USA. ³University of Colorado, Boulder, USA. ⁴Northern Arizona University, Flagstaff, USA. ⁵Colgate University, Hamilton, USA

Abstract

Cyanobacteria-dominated microbial mats provide the base of polar desert food webs. Through field-based observations, the McMurdo Dry Valleys Long Term Ecological Research (MCM LTER) program has demonstrated how microbial mat biomass can respond to long-term climate trends. Following an anomalous melt year in 2002, there was an increase in the biomass of black microbial mats dominated by Nostoc spp. (Gooseff et al. 2017). Here, we provide a landscape-scale perspective by examining trends in black mat areal coverage, soil gravimetric water content (GWC), and snow cover in Fryxell Basin in Taylor Valley. We analyzed 21 high resolution (~ 4-8 m²) multispectral images captured by WorldView satellites during 2009-2019 between October and February. Raster data products for each of the variables of interest were derived for each date for an area of interest (AOI) focusing on the terrestrial landscape. We used previously published algorithms using unmixing models based on spectral end-members collected in the field to create the derived data products (Salvatore et al., 2020, 2021, 2023). Our AOI represents primarily terrestrial polar desert and stream channel ecosystems below 200m elevation.

Across all imagery, the detectable black mat coverage was typically 0.2% (min = 0.03%, max 0.7%) of the AOI. We observed an expansion of detectable areal coverage of black mats from 2009-2019 (Adj. R² = 0.42, p = 0.001). GWC also showed a weak positive trend (Adj. R² = 0.27, p = 0.015) when only including imagery after melt had begun (after Dec 8). Snow cover showed a seasonal decreasing trend (Adj. R² = 0.29, p = 0.007), but no inter-annual trend. These observations demonstrate how remote imagery provides a landscape scale perspective on long-term trends documented by the MCM LTER. Specifically, an increase in soil moisture and black mat coverage in the landscape over the last decade.

586

Geologic Controls on Ice Sheet Dynamics in Wilkes Land: A Multi-Scale Analysis

Dr Mareen Loesing^1,2, A/Prof Dr Alan Aitken^1,2, A/Prof Dr Hélène Seroussi³, Prof Dr Joerg Ebbing⁴, Dr Lu Li²

¹Australian Centre of Excellence for Antarctic Science, The University of Western Australia, Perth, Australia. ²School of Earth Sciences, The University of Western Australia, Perth, Australia. ³Thayer School of Engineering, Dartmouth College, Hanover, USA. ⁴Department of Geosciences, Kiel, Germany

Abstract

Wilkes Land holds a key role in Gondwanan tectonics and for studying the influence of geological boundary conditions on the East Antarctic ice sheet. Despite its significance, this vast region remains one of the Earth's major geological blind spots, lacking fundamental knowledge. Australia, as a former tectonic neighbour of East Antarctica, serves as a valuable geological reference point and a well-covered base for validating established methods.
Using a combination of statistical and self-affine fractal interpolation methods can be helpful to gain a comprehensive understanding of how geological factors influence ice sheet dynamics across multiple scales. This involves integrating diverse data sources such as geophysical and geological datasets to map the geothermal regime and bed conditions. We seek correlations and relationships to predict realistic sub-glacial boundary conditions in Antarctica, facilitating both up- and downscaling of the spatial variability into large scale ice sheet models.
This multi-faceted approach aims to enhance our understanding of the required resolution and the complex interplay between geological conditions in ice sheet modelling, identifying the scales at which future data collection efforts are needed.

587

Ionospheric effects propagation from Antarctica towards the American continent during a moderate geomagnetic storm

Yamila Daniela Melendi^1,2, Marcos Paz^3,2, Trinidad Duran¹, Benjamin Urra⁴, Manuel Bravo⁴, Lorenzo De Pasquale⁵, Danny Scipión⁶, Jorge Namour^3,7,2, Maria Graciela Molina^2,7,3,8

¹IFISUR-CONICET, Bahía Blanca, Argentina. ²Tucumán Space Weather Center(TSWC), Tucumán, Argentina. ³FACET-UNT, Tucumán, Argentina. ⁴Centro de Instrumentación Científica, Universidad Adventista de Chile, Chillán, Chile. ⁵Universidad Tecnológica Nacional, Bahía Blanca, Argentina. ⁶Radio Observatorio de Jicamarca, Instituto Geofísico del Perú, Lima, Peru. ⁷UNT-CONICET, Tucumán, Argentina. ⁸Istituto Nazionale di Geofísica e Vulcanología (INGV), Roma, Italy

Abstract

The impact of changes in the composition of the thermosphere over the Antarctic sector resulting from geomagnetic storms can have significant effects on atmospheric dynamics and the ionosphere at various latitudes, highlighting the complex interconnection of different components of the Geospace. In particular, we analyze these complex mechanisms and their effects from the polar to the equatorial ionosphere using a multi-instrument approach.

Between February 26th and March 1st, 2023 a moderate geomagnetic storm caused disturbances throughout the ionosphere. To establish a longitudinal variation of the phenomenon, critical frequency of the F2 layer (foF2) was analyzed using data obtained by three ionosondes located in Tucumán, Argentina (27.0° S; 65.5° W, low-latitude station TUC), Bahía Blanca, Argentina (38.7° S; 62.3° W, mid-latitude station BB) and Jicamarca, Perú (11.7° S; 76.8° W, equatorial station). Results show a negative ionospheric storm for BB and TUC stations with a one-hour difference in onset time, and a positive ionospheric storm observed only at TUC station.

To attribute a physical explanation to the negative ionospheric storm, the relationship between O/N2 was studied by analyzing Global UltraViolet Imager maps, a spatial scanning ultraviolet spectrograph designed to measure the composition and temperature profiles of the MLTI region, as well as its auroral energy inputs, looking for changes in the thermospheric conditions. As a result, a decrease in the O/N2 ratio was evidenced during the day of the geomagnetic storm, observing a displacement from the South Pole (Antarctic region) towards the South American sector. By adding data that allow for comparison and reinforce the hypothesis, we analyzed vTEC maps derived from GNSS data, focusing on the Antarctic continent and South America.

In further studies, we plan to add data from other instruments in high latitude (e.g. Antarctic sector) and mid-latitude to enhance the coverage of the meridional sector in the Southern hemisphere.

595

An integrated, scale-appropriate, and data-driven approach to understanding the future of Antarctic terrestrial ecosystems in a warming climate

Assoc. Prof. Charles Lee¹, Marte Hofsteenge², Gabrielle Koerich³, Eva Nielsen³, Tamara Pletzer², Dr Jono Conway⁴, Prof. Nick Cullen², Dr Hanna Meyer⁵, Maite Lezama Valdes⁵, Prof. Peyman Zawar-Reza³, Assoc. Prof. Marwan Katurji³

¹University of Waikato, Hamilton, New Zealand. ²University of Otago, Dunedin, New Zealand. ³University of Canterbury, Christchurch, New Zealand. ⁴NIWA, Lauder, New Zealand. ⁵University of Münster, Münster, Germany

Abstract

The availability of liquid water is a key requirement for Antarctic vegetation, and elevated air temperatures linked to anthropogenic CO₂ are projected to increase meltwater generation from Antarctic glaciers, directly impacting the volume and distribution of liquid water in adjacent ice-free areas. A spatially explicit understanding of increased meltwater generation at biologically relevant scales under climate change scenarios is, therefore, foundational for evidence-based projections of future Antarctic terrestrial ecosystem functionality and biogeography. The New Zealand Antarctic Science Platform constructed a novel vertically integrated and multidisciplinary approach that starts with regional climate model outputs and ends with spatially explicit projections of vegetation distribution patterns at the basin level. Our approach incorporates

dynamic geo-statistical downscaling of climate projections;
translation of climatic patterns across the atmospheric boundary layer;
first-principle modelling of supraglacial melt, constrained with high-frequency eddy-covariance measurements;
mechanistic modelling of surface hydrological processes and patterns, validated using very-high-resolution airborne infrared imagery;
process-informed modelling of vegetation occurrence driven by meltwater availability; and
ultra-high-resolution aerial multispectral and hyperspectral baseline mapping of key vegetation habitats to understand natural variability and rate of change.

In this presentation, we report the current status of critical components within this ambitious project and highlight our next steps toward their integration. We argue that Antarctic vegetation can serve as a definitive indicator of meltwater presence, which is often too ephemeral and subtle to be detected using even in situ instrumentation. Our work will enable evidence-based attribution of changes in the physiology, composition, and spatial extent of these cold-adapted and slow-growing vegetations to environmental change resulting from elevated atmospheric CO₂ concentrations.

597

The Evolving Biogeography Register: machine-learning-assisted identification, extraction, and synthesis of Antarctic biogeographical knowledge

Assoc. Prof. Charles Lee¹, Augusto Pellegrinetti², Alejandra Verde Jirón³, Michael Meredyth-Young⁴, Fraser Morgan⁵

¹University of Waikato, Hamilton, New Zealand. ²Independent, Fiumicino, Italy. ³Scientific-a, Brinklaan, Netherlands. ⁴Antarctica New Zealand, Christchurch, New Zealand. ⁵Manaaki Whenua Landcare Research, Auckland, New Zealand

Abstract

To understand what Antarctic ecosystems may look like following environmental changes driven by a warming climate, it is necessary to have a systematic and comprehensive understanding of the extant biodiversity and biogeography. Despite the enormous body of information that exists across journal articles, book chapters, and gray literature such as student theses and institutional reports, there are no taxonomically and spatially comprehensive sources of Antarctic biogeographical knowledge. As part of the New Zealand Antarctic Science Platform, we designed and implemented an informatic pipeline that retrieved more than 250,000 potentially relevant articles using expert-approved broad search terms from full-text search engines. Natural language processing, data structuring, and machine learning were then applied to the retrieved articles to identify those containing relevant information (i.e., spatially explicit occurrence of taxonomically resolved biological species). We then used a combination of supervised and unsupervised machine learning algorithms to extract biogeographical knowledge for the Ross Sea region from almost 5,000 PDFs of relevant articles as well as manually identified knowledge of biological and ecological processes to aid the construction of ecological models.

With annotations by experienced researchers and a consensus-based annotation process, we achieved greater fidelity than conventional workflows for collating biogeographical information, and the incorporation of machine learning enabled us to identify and extract information that would have otherwise taken many person-years. The compiled information is likely the most comprehensive body of knowledge on Antarctic biodiversity and biogeography in existence, and it will form the basis of our projection for ecosystem change using process-based ecological modeling and predictions of environmental attributes downscaled from regional climate models. We are working to expand this ‘Evolving Biogeography Register’ to the whole of Antarctica and other targeted taxa, and we welcome solicitations for collaborations to utilize this novel data set and capability.

598

Hauwai-20: An autonomous biological sampler for year-round biological collection and oceanographic measurements under Antarctic sea ice

Prof. Craig Cary¹, Darryn Collier², Eric Jackson², Andrew Mahon³, Assoc. Prof. Charles Lee¹, Prof. Sandy Morrison¹, Prof. Ian Hawes³

¹University of Waikato, Hamilton, New Zealand. ²Cellula Robotics Ltd., Vancouver, Canada. ³University of Waikato, Tauranga, New Zealand

Abstract

Sea ice is essential in supporting the primary production critical for the polar marine food web. The seasonal extent of Antarctic sea ice has recently undergone a dramatic decline, and we know little about how such changes may propagate through marine ecosystems. The composition and structure of the critical sympagic community are unknown during most of the year since our access has been largely restricted to the Austral spring and summer. The few hard-won winter datasets available reinforce the importance of ice-associated processes. Year-round sampling of the sea ice would provide an essential data set to better understand how the community might respond to environmental change. Supported by the Antarctic Science Platform, Hauwai-20 was designed and built for year-round under-ice sampling through a collaboration between University of Waikato and Cellula Robotics. The name ‘Hauwai’ was gifted by a senior Māori linguist and represents a linkage between Māori knowledge (mātauranga Māori) indigenous to Aotearoa and cutting-edge Antarctic science.

The sampler is moored on the seafloor, and an integrated winch raises a float head containing the sample intake, CTD, altimeter, camera, fluorometer, and PAR sensors. The upwards-facing altimeter positions it just under the sea ice for sampling. An ADCP mounted to the sampler on the sea floor provides continuous real-time current data to assure optimal float head deployment. The sampler can take up to 150 discrete samples stored in sealed pucks. Each puck contains up to three filters with user-selectable pore sizes from 0.22 to 1000 μm. A displacement pump pulls a user-defined volume through the filters, then a preservative is injected into the puck before it is sealed. The flow path is sterilized between samples. The sampler can operate via a power-and-data cable from shore or autonomously with a built-in battery pack, with the former enabling remote operation from off-continent locations.

599

Atmospheric blocking-driven unprecedented extreme warming over East Antarctica in March 2022

Prof. Minghu Ding¹, Dr. Sai Wang¹, Prof. Cunde Xiao²

¹Chinese Academy of Meteorological Sciences, Beijing, China. ²Beijing Normal University, Beijing, China

Abstract

Recently, Antarctic seems to be experiencing rapid climatic changes and frequent climate extremes, such as a sudden decrease in sea ice extent since 2016 and the new highest air temperature record at Esperanza station in the Antarctic Peninsula in February 2020. South Pole is also proved in a warming trend during the past decades (Clem et al. 2020). Antarctica seems to be entering a new era of frequent extreme events, and the climate extremes in Antarctica have been gaining increasing attention recently. On 18^th March, 2022, a sudden and drastic increase in surface air temperatures was observed in Dome C. This unprecedented extreme warming event attracted worldwide attention. In this manuscript, we shed light on the governing mechanisms accounting for this unprecedented extreme warming event and revealed for the first time that the blocking high over the Wilkes Land is the optimal circulation accounting for the occurrence of extreme warming events over Dome C during the past 40 years. Moreover, we found that a stronger blocking-driving poleward flow may cause a warmer extreme event. Around March 18, 2022, the currently strongest circulation driven by the blocking over the Wilkes resulted in the unprecedented extreme warming event over Dome C. However, There is no evidence on increasing of warming events.

600

Making connections: piloting an Antarctic artists and writers program in South Africa

Dr Charne Lavery¹, Associate Professor Jean Brundrit²

¹University of Pretoria, Pretoria, South Africa. ²University of Cape Town, Cape Town, South Africa

Abstract

South Africa has an established research presence in the Southern Ocean, on two sub-Antarctic islands and on the continent of Antarctica. However, this very important activity is contained within scientific structures and does not form part of the broader South African imagination. This pilot project aims to shift ideas and information about the Antarctic, subantarctic and Southern Ocean environments, in their connection to South Africa and Africa. It aims to do so by gathering and analysing existing Antarctic creative work, and creating conditions for generating new writing and artwork.

Antarctica and the Southern Ocean is geographically remote and therefore does not feature in most South Africans’ experience. The pilot project plans to address that by providing opportunities for artists and writers to be immersed in this environment and to draw from this experience to produce creative works. It will conduct feasibility studies about the potential for a longer term programme, particularly given the constrained resources of the South African science project. Alternative venues and means for generating creative responses may need to be put in place due to the limited berths available on the ship and bases. The project will also explore some of the creative works that have already been produced with a view to making connections between them, and laying the groundwork for future artistic and scholarly production.

The project will provide relevant data for other Antarctic programmes in the Global South who operate with limited resources, and could contribute to promoting transformation, in terms of race, class and gender, in Antarctic activities.

At this moment of climate crisis and change, the arts can play a crucial role in conveying information as well as the addressing questions of emotion and value. This is particularly important as Africa is predicted to be the continent worst affected by climate change.

601

Using a statistical framework to detect ecological regime shifts in Antarctica.

MR John Lyons

QUT, Brisbane, Australia

Abstract

Detecting ecological regime shifts is crucial for understanding and managing the impacts of environmental changes on ecosystems. The significance of this research lies in its potential to provide warnings of ecological changes, better understanding of species, and help detect where possible regime shifts will occur in the future.

This study focuses on utilizing a statistical framework to identify regime shifts in Antarctica, a region highly vulnerable to climate change. The proposed statistical framework leverages time-series data to identify abrupt and significant changes in ecological variables. By analyzing ecological datasets, potential regime shifts can be detected by identifying periods of abrupt change. The methodology incorporates techniques such as the STARS test, a widely used non-parametric approach, and Nearest Neighbour test, a spatial statistical technique to pinpoint abrupt changes in time-series data.

By investigating the relationship between the tipping points and changes in temperature, precipitation, and wind patterns, I hope to uncover potential drivers responsible for the observed ecological changes.

I have trialled this framework on a large collection of penguin data provided by the MAPPPD project to highlight possible regime shifts. We have detected 3 areas of regime shifts in penguin colonies around Antarctica. By understanding the drivers and locations of these shifts, effective conservation and management strategies can be developed to mitigate their impacts.

604

Cross-Boundary Awareness and Mitigation Strategies: Assessing Indonesian Public Engagement with Antarctic Microplastic Pollution

Ms Sahnaz Vivinda Putri¹, Mr Rifaldy Fajar²

¹Department of Management, International University Semen Indonesia, Gresik, Indonesia. ²Computational Biology Laboratory, Yogyakarta State University, Sleman, Indonesia

Abstract

The escalating threat of climate change to Antarctic and Southern Ocean environments has brought microplastic pollution to global attention. Despite Indonesia's distance from polar regions, as the world's largest archipelagic nation, it significantly contributes to marine plastic pollution. This study examines Indonesian public awareness, concern, and engagement with Antarctic microplastic pollution, exploring perceptions and motivations for mitigating these global challenges. Combining quantitative and qualitative methods, this research undertakes a comprehensive analysis of Indonesian perceptions towards Antarctic microplastic pollution. A systematic literature review identifies gaps in public knowledge and engagement strategies. A nationwide online survey (n=1,200) assesses public awareness, concern levels, and willingness to engage in pollution reduction practices, using stratified sampling to ensure demographic representation. Additionally, in-depth interviews with 40 environmental activists, policymakers, and academics provide nuanced insights into international environmental engagement. Logistic regression analysis explores predictors of awareness and engagement, with results presented alongside 95% confidence intervals and significance levels set at p<0.05. Initial findings indicate that only 17.6% (CI 16.4-18.8%) of surveyed Indonesians are aware of Antarctic microplastic pollution. However, among those aware, concern for its environmental impact is notably high (mean score of 8.2 on a 10-point scale, CI 7.9-8.5), yet only 5.2% (CI 4.6-5.8%) report active involvement in pollution reduction practices or advocacy. Logistic regression identifies education level, environmental activism, and social media use as significant predictors of awareness and engagement. Interviews underscore a gap between global environmental concerns and local action, highlighting social media's potential in bridging this divide. This study reveals a significant but limited awareness and engagement among Indonesians regarding Antarctic microplastic pollution, emphasizing the need for innovative outreach efforts to bridge geographical and psychological distances. Enhancing global environmental stewardship through social media and community-based initiatives could amplify efforts to combat microplastic pollution, contributing to the preservation of Antarctic and Southern Ocean environments.

605

An integrated approach to marine plankton and micro-nekton capture and research at the Australian Antarctic Division

Mr Rob King¹, Mr Steve Whiteside¹, Dr So Kawaguchi¹, Mr Michael Murphy², Mr Jia Wei Tan³, Dr Brian Winship³, Dr Christopher Chin³, Dr Michael Woodward³

¹Australian Antarctic Division, Kingston, Australia. ²Alto Consulting Engineers, Brisbane City, Australia. ³Australian Maritime College, Launceston, Australia

Abstract

Determining the physiological tolerance and the behavioural and life history plasticity of marine plankton and micro-nekton to climate change, ocean acidification and other stressors is essential for the development of models seeking to predict future ecosystem scenarios in the Southern Ocean. The ability of such models to make reliable ecosystem projections depends on both the quality of the data inputs and the diversity of species included. Such studies therefore rely on a broad array of specimens being routinely captured and then maintained in perfect condition such that the data generated from manipulative experiments is meaningful. In the past, nets have been relied upon to collect specimens but these, unfortunately, damage many specimens, particularly the gelatinous plankton. To resolve this the Australian Antarctic Division is developing an integrated approach to the collection of plankton and micro-nekton utilising a vessel-integrated wet well for gentle specimen capture and containerised aquaria for experimentation and transport at sea which interface directly with a shore based research aquarium facility. The shore based facility will enable long term live specimen research after the voyage and will enhance the opportunities to conduct collaborative research with international phyla experts. Such collaborations will be critical to accelerating progress with key phyla and closing life cycles in the laboratory, thereby enabling research on all life stages. This presentation will describe the integrated system and the anticipated timeline to full operational capability along with examples of capture from ice algae communities, plankton, krill and juvenile fish.

606

Late Quaternary dynamics of the Cook and Ninnis glacial system (East Antarctica): new insights from continental margin geophysical data

dr Laura De Santis, Flavio Accaino, Daniela Accettella, Florence Colleoni, Andrea Cova, Lorenzo Facchin, Fabrizio Zgur

National Institute of Oceanography and Applied Geophysics OGS, Sgonico, Italy

Abstract

The sector of the East Antarctic Ice Sheet that terminates in the Cook Ice Shelf and Ninnis Glacier drains most of a large marine ice sheet covering the Wilkes Subglacial Basin, whose ice volume is equivalent to 3-4 m of global sea level rise. Long-term climate projections and multiproxy studies of ice and sediment core records suggest that the retreat of the ice sheet in this area, which is considered currently stable, could be triggered by the intrusion of warm ocean water in the future.

The Italian Survey 2022 of the Programma Nazionale delle Ricerche in Antartide (PNRA) used the icebreaker L. Bassi to map two systems of canyons and hills at the mouth of the presumed glacial valleys in front of the Cook and Ninnis glaciers. The combination of geomorphologic, seismic, oceanographic and sedimentary data (see also abstract from Torricella) allowed the identification of a variety of processes active on the seafloor today and in the late Quaternary, indicating past instability of the continental margin. The information obtained supports previous hypotheses on ice sheet sensititivity to past warming and helps to reconstruct the dynamics of different glaciers in relation to paleoclimatic and ocean circulation changes.

613

Limited benefits of increased spatial resolution for sea ice in HighResMIP simulations

Dr. Julia Selivanova¹, Dr. Doroteaciro Iovino¹, Prof. Marcello Vichi^2,3

¹CMCC Foundation - Euro-Mediterranean Center on Climate Change, Bologna, Italy. ²Department of Oceanography, University of Cape Town, 7701, Rondebosch, Cape Town, South Africa. ³Marine and Antarctic Research centre for Innovation and Sustainability (MARIS), University of Cape Town, 7701, Rondebosch, Cape Town, South Africa

Abstract

State-of-the-art coupled climate models struggle to accurately simulate historical variability and trends of Antarctic sea ice, impacting their reliability for future projections. Increasing horizontal resolution in models is expected to improve the representation of coupled atmosphere-ice-ocean processes at high latitudes. Here, we examine the historical changes in Antarctic sea ice area and volume in HighResMIP simulations against satellite datasets and ocean reanalyses with the objective to assess the benefits of increased spatial resolution. Our results show no considerable improvements in the main essential climate variables of Antarctic sea ice using finer horizontal resolutions reduced to 0.25º in the ocean and 50 km in the atmosphere. Limited improvements are reported in the simulation of historical trends in sea ice area known to be negatively biased during the satellite observational period. These improvements are nevertheless model dependent, and we associate them to the use of model components with more refined parameterizations of sea-ice physics. Given the high computational cost of climate-scale simulations at increased spatial resolution, we advocate prioritizing enhancements in sea-ice physics and the interactions among model components in coupled climate simulations.

617

Seasonal variability in trophic ecology interactions among juvenile notothenioid fish species in the South Shetland Islands: an integrative approach

Dra. Eugenia Moreira^1,2, Dr. Manuel Novillo³, Dr. Esteban Barrera-Oro⁴

¹Instituto Antártico Argentino, CABA, Argentina. ²Laboratorio de Biología Funcional y Biotecnología (BIOLAB), INBIOTEC-CONICET, UNCPBA-CICPBA, UNCPBA, Facultad de Agronomía, Azul, Argentina. ³Instituto de Diversidad y Ecología Animal (IDEA), CONICET, Cordoba, Argentina. ⁴División Ictiología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia- MACN-CONICET, CABA, Argentina

Abstract

Although extensive research has been conducted on the trophic ecology of many cryonotothenioid species, little attention has been given to the juvenile fraction of their populations. Particularly, the inter-annual variation of the diet composition and feeding habits of the youngest notothenioid stages has been poorly explored. This study analysed the trophic ecology of 755 specimens from five notothenioids species (Notothenia rossii, Notothenia coriiceps, Nototheniops nudifrons, Trematomus newnesi and Harpagifer antarcticus), collected in the inshore waters of Potter Cove, South Shetland Islands, during four consecutive sampling seasons from 2008 to 2012. The stomach-content analysis, using the IRI % and the Amundsen et al. (1996) methods, provided data on feeding habits and trophic niche breadth. Our findings suggest that the species are demersal and benthophagous, with a generalized feeding strategy. They primarily prey on demersal-benthic amphipods, mainly from the genus Gondogeneia and Oradarea, as well as on other epibenthic invertebrates associated with macroalgal beds. Significant differences were observed in the diet of all species between sampling periods, and ontogenetically, only in N. rossii and T. newnesi. Based on the estimated trophic levels, the juvenile cryonotothenioids were identified as secondary consumers. Ambush feeding was the predominant feeding behaviour in all species, with grazing also observed in N. rossii and N. coriiceps. By comparing our findings on the youngest juvenile stages of the fish community with literature information on the trophic ecology of the largest juvenile and adult stages of the same species at Potter Cove, we identified both differences and similarities. Additionally, we performed a biomarkers analysis for N. rossii and N coriiceps to compare and complement the information arisen from conventional methods, highlighting the strengths and weaknesses of the different techniques. The combined use of conventional methods and trophic biomarkers is essential for understanding trophic interactions.

618

Climate controls on water isotopes in Antarctic precipitation - insights from innovative water tracers in ECHAM6

Qinggang Gao^1,2, Louise C. Sime², Martin Werner³, Alison J. McLaren²

¹University of Cambridge, Cambridge, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³Alfred Wegener Institute, Bremerhaven, Germany

Abstract

We present new work that improves our understanding of the controls on Antarctic precipitation and ice core records. This is critical for gaining insights into polar changes. The work relies on our implementation of innovative water tracing diagnostics in an atmospheric general circulation model (Gao et al. 2024). These tracers provide new precise information on moisture source locations and properties of Antarctic precipitation. Heavy precipitation in Antarctica is sourced by longer-range moisture transport: it comes from 2.9° more equatorward sources compared to the rest of precipitation, averaged over Antarctica. Precipitation during negative phases of the Southern Annular Mode (SAM) also comes from more equatorward moisture sources by 2.4° averaged over Antarctica than precipitation during positive SAM phases, likely due to amplified planetary waves during negative SAM phases. The results support the conventional practice of interpreting deuterium excess in Antarctic precipitation in terms of source sea surface temperature, without concerning source relative humidity relative to sea surface temperature, source 2 m relative humidity, and source 10 m wind speed. Moisture source properties exhibit stronger correlations with the logarithmic definition of deuterium excess than the classical linear definition of deuterium excess. There is no added value to include δD for the reconstruction of source temperature in addition to deuterium excess. Nevertheless, we highlight the uncertainties in the quantitative relationship between deuterium excess and source temperature due to the parameterisation of supersaturation conditions in mixed clouds and post-depositional effects. Overall, the novel water tracing diagnostics enhance our understanding of the controlling factors of Antarctic precipitation and ice core water isotope records.

Gao Q., Sime L. C., McLaren A. J., Bracegirdle T. J., Capron E., Rhodes R. H., Steen-Larsen H. C., Shi X., and Werner M., 2024, Evaporative controls on Antarctic precipitation: an ECHAM6 model study using innovative water tracer diagnostics, The Cryosphere

620

Ionospheric Total Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

Dr Juan Carlos Valdes-Abreu^1,2, Dr Marcos Díaz^1,2, Dr Manuel Bravo³, Mrs Yohadne Stable-Sánchez^1,2

¹Space and Planetary Exploration Laboratory (SPEL), Faculty of Physical and Mathematical Sciences, University of Chile, Santiago, Chile. ²Department of Electrical Engineering, Faculty of Physical and Mathematical Sciences, University of Chile, Santiago, Chile. ³Centro de Instrumentación Científica, Universidad Adventista de Chile, Chillan, Chile

Abstract

This is one of the first papers to study the ionospheric effects of two solar eclipses that occurred in South America and Antarctica under geomagnetic activity in different seasons (summer and autumn) and their impact on the equatorial ionization anomaly (EIA). The changes in total electron content (TEC) during the 15 February 2018 and 30 April 2022 partial solar eclipses will be analyzed. The study is based on more than 390 GPS stations, Swarm-A, and DMSP F18 satellite measurements, such as TEC, electron density, and electron temperature. The ionospheric behaviors over the two-fifth days on both sides of each eclipse were used as a reference for estimating TEC changes. Regional TEC maps were created for the analysis. Background TEC levels were significantly higher during the 2022 eclipse than during the 2018 eclipse because ionospheric levels depend on solar index parameters. On the days of the 2018 and 2022 eclipses, the ionospheric enhancement was noticeable due to levels of geomagnetic activity. Although geomagnetic forcing impacted the ionosphere, both eclipses had evident depletions under the penumbra, wherein differential vertical TEC (DVTEC) reached values <−40%. The duration of the ionospheric effects persisted after 24 UT. Also, while a noticeable TEC depletion (DVTEC∼−50%) of the southern EIA crest was observed during the 2018 eclipse (hemisphere summer), an evident TEC enhancement (DVTEC > 30%) at the same crest was seen during the eclipse of 2022 (hemisphere autumn). Swarm-A and DMSP F18 satellite measurements and analysis of other solar eclipses in the sector under quiet conditions supported the ionospheric behavior.

621

Investigating Environmental Influences on Soil Microbial and Animal Diversity in Victoria Land

Dr. Fabiana Canini¹, Prof. Luigimaria Borruso², Prof. Solveig Tosi³, Dr. Marta Eleonora Elisabetta Temporiti³, Prof. Laura Zucconi^1,4

¹Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy. ²Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen, Bolzano, Italy. ³Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy. ⁴Institute of Polar Sciences, National Research Council of Italy, Messina, Italy

Abstract

Victoria Land, located in the Ross Sea area, contains a diverse range of ecosystems that have remained largely untouched by human activity. Each ecosystem is identified by its unique soil type, including both arid and humid soils. The innermost valleys typically contain arid soils, while the lower-lying areas, such as those near lakes and transient glacial melt streams known as hyporheic zones, are predominantly humid soils that are primarily inhabited by cyanobacteria. During the summer months, these hyporheic soil areas become hotspots for biological activity and play a crucial role in providing organic matter to adjacent arid soils through processes such as aeolian dispersion, as well as the erosion, transportation, and deposition of melt streams. Conversely, soils situated far from lakes or melt streams lack significant aggregation, exhibit poor moisture retention capacity, and lack substantial sources of organic matter. Microbial activity in these areas is severely limited. Despite numerous studies contributing to understanding the diversity within these unique ecosystems, our knowledge regarding the factors influencing microbial diversification and interactions among different community members remains limited. To address this gap, soil samples were collected from 11 localities spanning the entirety of Victoria Land, including both areas adjacent to water sources and those distant from them. A DNA metabarcoding approach was employed to characterize the diversity of bacteria, fungi, and metazoans in these soil samples. While bacterial diversity remained relatively high across all studied localities, the fungal and metazoan components of the communities were strongly limited. Furthermore, the diversity and composition of these three biological compartments were compared across various research sites and soil types. This comparison was then related to their respective compositions and different edaphic parameters, aiming to provide new insights into the primary abiotic and biotic factors driving microbial diversification within these ecosystems.

623

Major Haemorrhage and Tranexamic acid in the Polar environment- Best Practice vs Deliverability: Intravenous vs Oral Administration.

Dr Matthew Warner, Dr Jonathon Lowe

British Antarctic Survey Medical Unit, Plymouth, United Kingdom

Abstract

There are published data demonstrating that the use of Tranexamic Acid (TXA) in Major Haemorrhage (for example secondary to Trauma) leads to reduction in mortality; the outcome of which is that TXA is now routinely recommended and administered within the medical community.

The data suggest that early intravenous bolus follow by an infusion provides the best outcomes. However, how does this translate into a polar environment? It is recognised common issues are that intravenous access may not be feasible, drugs and infusions may freeze, even if there was the medical resource available to undertake these procedures. It should also be acknowledged that there is often a significant delay between time of incident and arrival of or to trained medical assistance.

With pharmacological support it has been determined that the pharmacodynamics of TXA is favourable for relatively rapid oral absorption, and there should be relatively rapid bioavailability if TXA is chewed.

Thus in response, the British Antarctic Survey Medical Unit has instigated the use of oral TXA to be chewed at the point of injury (if able). TXA tablets are now carried as part of Immediate Aid Packs which are designed to deliver early and basic airway support, haemorrhage control and analgesia- administered by non-medical colleagues who have had appropriate training.

This change is expected to give patients who suffer major haemorrhage a significantly reduced time of administration and thus biological benefit over the previous approach, which required a patient to be in a suitable environment and with suitably skilled personnel to be able to deliver TXA via an intravenous route.

636

Deciphering the microbiota of Cryptopygus antarcticus and its relationship to the bacterial community of the surrounding soil

PhD Alexis Gaete¹, Daniel E. Palma¹, Cristian Arenas¹, Samuel E. Jara¹, PhD Mauricio González¹, PhD Jacquelinne J. Acuna², PhD Francisco P. Chavez¹, PhD Andres E. Marcoleta¹, PhD Milko A. Jorquera², PhD Veronica Cambiazo¹

¹Universidad de Chile, Santiago, Chile. ²Universidad de la Frontera, Temuco, Chile

Abstract

Cryptopygus antarcticus is a native species in Antarctic Peninsula with ecological relevance in soils, such as organic decomposition and nutrient cycling. This species could be the first to colonize thawed soils, dispersing microorganisms through its endomicrobiota. In this work, we characterize the diversity and functional potential of the microbiota of C. antarcticus and its relationship with the surrounding soil and uncolonized soils. Three sites were defined on King George Island and 12 samples of springtails and surrounding soil were collected. In addition, uncolonized soil was collected near the Ecology glacier. Taxonomic diversity was analyzed by Illumina sequencing of the V4 region of the 16S rRNA gene and taxonomic assignment by Nanopore sequencing of the V1-V9 region. Functional characterization of the bacterial communities was performed with the FAPROTAX tool. The number of observed amplicon sequence variants (ASVs) and the estimated richness for the soil microbiota were significantly higher compared to the springtail microbiota. A small number of ASVs, assigned to Proteobacteria, Bacteroidota and Actinobacteriota, were shared between the springtail microbiota and the surrounding soil or uncolonized soil. However, the dominant taxa associated with C. antarcticus differed from the soil microbiota and among springtail samples. The most abundant ASVs corresponded to representatives of the genera Rickettsia, Alistipes and Akkermansia. In the microbiota of springtails, intestinal functions, manganese oxidation, fumarate reduction, plastic and hydrocarbon degradation were predominant, while in the surrounding and uncolonized soil, functions related to ammonium oxidation, nitrification and oxidation of organic compounds were predominant. The functions of nitrite reduction, nitrogen fixation and other nitrogen cycle processes were shared in all samples. The microbiota of springtails inhabiting King George Island differ in taxonomy, alpha, beta diversity and metabolic prediction with respect to the surrounding soil microbiota, however, surrounding soils and uncolonized soils do not show significant differences.

639

Quantifying photosynthetic biomass in Taylor Valley, Antarctica, and modeling habitat suitability in a changing climate

Mark Salvatore¹, John Barrett², Michael Gooseff³, Eric Sokol⁴, Khum Thapa Magar³, Peter Doran⁵, Byron Adams⁶, Joseph Levy⁷, Sarah Power², Morgan Wood², Anna Wright³

¹Northern Arizona University, Flagstaff, AZ, USA. ²Virginia Tech, Blacksburg, VA, USA. ³University of Colorado Boulder, Boulder, CO, USA. ⁴Battelle, National Ecological Observatory Network, Boulder, CO, USA. ⁵Louisiana State University, Baton Rouge, LA, USA. ⁶Brigham Young University, Provo, UT, USA. ⁷Colgate University, Hamilton, NY, USA

Abstract

Over the past decade, improvements in remote sensing technologies and techniques have enabled the monitoring of photosynthetic biomass over space and time in the remote McMurdo Dry Valleys (MDV) of Antarctica. Microbial mat and moss communities have been previously recognized as important components of the Antarctic ecosystem for nearly half a century, yet the ability to detect and monitor these communities has been historically limited by several factors, including the small spatial scales and patchiness of these communities across the landscape as well as the challenges and constraints of conducting field work in the Antarctic. With the availability of high-resolution multispectral remote sensing data, however, we are now able to holistically study the distribution and drivers of photosynthetic activity, particularly in the context of other environmental variables.

In this presentation, we will summarize these recent efforts and provide updated photosynthetic biomass estimates for Taylor Valley, Antarctica. We will also discuss the spatial and temporal variability observed throughout the decade of available high-resolution remote sensing data and our attempts to understand the environmental drivers of photosynthetic activity throughout the MDV. In combination with meteorological station and stream gage data from throughout the region, machine learning algorithms allow us to better constrain the environmental drivers of photosynthetic activity and to make educated predictions based on future climate projections. The MDV are expected to get warmer and wetter under a warming global climate, potentially resulting in frequent rainfall in the MDV where rain has only been recorded on a few occasions. Our efforts enable the long-term monitoring of photosynthetic activity and broader ecosystem processes throughout the MDV, and allow us to make data-driven predictions based on a new understanding of the environmental drivers of these communities.

640

Planning and management of touristic and recreational activities under the Antarctic Treaty System – now and into the future

Ms Hubertha Wichers

University of Canterbury, Christchurch, New Zealand

Abstract

Concerns about the environmental impacts of tourism are widely published in the scholarly literature. In contrast, recreation by National Antarctic Programmes (NAPs) receives very little attention. Article 3 of the Protocol on Environmental Protection to the Antarctic Treaty requires all activities conducted in the Antarctic Treaty area to consider the protection of the Antarctic environment. Recommendation XV-5 (1989) specifically requires environmental monitoring of recreational activities.

In this presentation, I will discuss the results of a study that evaluated the environmental impact assessments (EIAs) prepared by 41 NAPs and 34 tourism operators and aimed at understanding how tour operators and NAPs consider the environment and manage touristic and recreational activities. In addition to the document analysis of EIAs, a survey of recreational activities at Scott Base and a small number of semi-structured interviews offered a richer understanding of how recreational and touristic activities are managed via different regulatory mechanisms – both hortatory and binding.

My research findings indicate that, generally, tourism EIAs and regulatory mechanisms for tourism are well-developed by tour operators, supported by the International Association of Antarctica Tour Operators. However, only three EIAs prepared by NAPs considered recreation at all, and only one of these comprehensively addressed recreation. The lack of environmental consideration regarding recreational activities engaged in by NAP staff may result in unanticipated environmental impacts that could cause reputational damage to NAPs.

While the challenge for tour operators will be to manage their collective and cumulative environmental impacts, the challenge for NAPs will be to take a more comprehensive and pan-programmatic approach to assessing the environmental impacts of their activities in the first place. I will conclude by offering suggestions on how such challenges can be addressed in the future.

642

Sensitivity of surface winds in coastal Antarctica to configuration of the regional Met Office Unified Model

Dr Thomas Caton Harrison¹, Dr Thomas Bracegirdle¹, Dr Adrian Lock², Dr Hua Lu¹, Dr John King¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²Met Office, Exeter, United Kingdom

Abstract

Antarctic coastal surface winds are closely linked to ocean circulation, ice sheet stability, sea ice and local ecosystems. As a result, these regional winds have global importance. We investigate the sensitivity of surface winds to atmospheric model configuration and physics in a representative and well-observed sector of east Antarctica encompassing the Mawson coast and Prydz Bay.

The Met Office Unified Model (MetUM) is run in a one-way nested setup using grid spacing of 4, 12 and 40 km. Simulations are performed across a selection of 10 months, 5 from austral summer and 5 from austral winter. The realism of the MetUM is evaluated using surface, upper-air and satellite observations. Modifications to various ill-constrained parameterised processes are tested, including stable boundary layer turbulence, sub-grid orography, sea ice roughness and air-sea exchange.

Compared with a control simulation, the largest impacts on surface winds result from enhancing the standard deviation of the sub-grid orography and from switching to a sea ice roughness parameterisation which gives much higher roughness lengths over marginal ice (as used in HadGEM3-GC3.1). Stable boundary layer parameterisation affects the depth of the offshore coastal low-level jet. Impacts are highly regionally varied, with polynya-forming winds off Cape Darnley especially sensitive to the range of tests. Coastal surface winds are affected most by the sensitivity tests during boreal winter. The results underscore the wide range of physical processes which need to be constrained over the coastal margins for faithful characterisation of surface winds.

648

Exploring the carbon benefit of protecting the Southern Ocean: assessing a large-scale marine reserve in the Ross Sea

Elizabeth Francis¹, Dr Emma Cavan², Dr Matthew Savoca³, Dr Cassandra Brooks¹

¹The University of Colorado, Boulder, USA. ²Imperial College London, London, United Kingdom. ³California Marine Sanctuary Foundation, Monterey, USA

Abstract

Marine protected areas (MPAs) can support climate change adaptation and mitigation by reducing stressors and conserving blue carbon ecosystems that sequester and store carbon within ocean and coastal ecosystems. Most research on blue carbon has been focused on coastal marine ecosystems with a limited understanding of how MPAs can contribute to open ocean carbon sinks. Building upon the recognized role of MPAs in climate mitigation, this study proposes a framework to incorporate open-ocean pelagic carbon processes in MPAs, using the Ross Sea region MPA as a case study. First, we estimate the carbon sequestration of whales, phytoplankton, and krill in the larger Southern Ocean and then in the Ross Sea region. We show that the Southern Ocean and the Ross Sea act as a powerful carbon sink that has the potential to store and sequester more carbon than traditional coastal blue carbon projects. MPA managers should consider how to quantify and protect existing sequestration pathways in pelagic ecosystems. Based on our results, we propose a framework to estimate pelagic blue carbon sequestration, implement blue carbon protection, monitoring strategies, and governance and institutional frameworks. Our framework aims to provide a guide for researchers, policymakers, MPA managers, and practitioners on potential pathways to integrate open ocean blue carbon into MPA management. Despite the complexity of marine carbon systems, this approach can advance our understanding of carbon processes and effective MPA management for climate change mitigation.

652

The spatial extent of temperature trends and extreme events across Antarctica for the period 2003-2021

Eva Bendix Nielsen, Dr Marwan Katurji, Prof. Peyman Zawar-Reza

University Of Canterbury, Christchurch, New Zealand

Abstract

Understanding air temperature trends and the spatial distribution of extreme events across Antarctica are highly important for assessing the impact on both the physical and biological systems across the continent. Previous studies have provided useful information from automatic weather station records for identifying such trends and events, however, this only provides knowledge about a certain location, influenced by local processes and terrain. Spatial information about Antarctic regional temperature extremes and the associated weather patterns influencing their variability are lacking.

This study presents a spatial analysis of temperature trends and extremes across Antarctica for the period 2003-2021. Antarctica was clustered into 12 climate regions using austral summer and annual mean temperature trends from satellite derived near-surface air temperature product AntAir ICE. All inland climatic regions show an overall warming and with the exception of the Ross Sea Region, an overall cooling is present in the coastal clusters. In agreement with other studies the Antarctic Peninsula had the largest significant cooling trend of -0.12 C°/Yr in the annual mean trend, and the largest significant warming trend was found of 0.08 C°/Yr for the austral summer and 0.07 C°/Yr for the annual mean for the Ross Sea cluster covering coastal Victoria Land.

Extreme temperature event was derived based on the spatial extent of the cluster exceeding the 95^thpercentile of the austral summer temperature record. Using an atmospheric circulation reanalysis product the synoptic weather patterns related to these extreme events were investigated and the spatial distribution of each warming event was identified. This study provides insights into the spatial distribution and the impact of atmospheric circulation on its regional climates. Meridional flow onto the coastline from a blocking high led to localised warming within a single cluster whereas the presence of a large inland high caused widespread warming across multiple clusters.

653

Comparison of the September total ozone column during Antarctic SSW events and the non-SSW conditions

Ruixian Yu¹, Dr Yu Shi¹, Prof Gennadi Milinevsky^1,2,3, Dr Asen Grytsai⁴, Dr Volodymyr Reshetnyk⁴, Dr Oleksandr Evtushevsky⁴, Dr Andrew Klekociuk^5,6

¹Jilin University, Changchun, China. ²National Antarctic Scientific Center, Kyiv, Ukraine. ³Main Astronomical Observatory of NAS of Ukraine, Kyiv, Ukraine. ⁴Taras Shevchenko National University of Kyiv, Kyiv, Ukraine. ⁵University of Adelaide, Adelaide, Australia. ⁶Australian Antarctic Division, Kingston, Australia

Abstract

Antarctica is a unique geographical environment characterized by minimal human activity impact and extremely sensitive to global climate change. Due to the ozone hole appearing over Antarctica since the mid-1980s, it is significant to study the temporal and spatial characteristics of the total ozone column in the region to understand regional and global atmospheric changes. One of the most dramatic events in the spring in Polar Regions is sudden stratospheric warming (SSW), which strongly impacts the stratosphere and provides valuable information. This study explored the association between SSW events and ozone content over Antarctica. We use Multi-Sensor Reanalysis data to study total ozone variations in Antarctica in September. We use ozone data from nine Antarctic and sub-Antarctic stations: Amundsen-Scott, Rothera, Faraday/Vernadsky, Neumayer, Syowa, Zhongshan, Davis, Dumont d'Urville, and the Macquarie, located at the South Pole, the edge regions of Antarctica and at sub-Antarctic. The time range 1979–2022 is used for the study ozone values variations, when three prominent SSW events occur in 1988, 2002 and 2019. We analyze September average ozone values for these nine stations for each SSW year and non-SSW years. The years with less developed stratosphere warmings are examined as well. It is clear that the ozone level in Antarctica in SSW years is significantly higher than that in non-SSW years. However, total ozone variations significantly depend on the station's location, the variable shape of the stratospheric polar vortex, and its location relative to the South Pole. The trend and variations in total ozone may lead to or serve as a precursor to the occurrence of SSW. Because it is evident that human activity can impact the atmosphere composition and ozone layer, whether the frequency of occurrence of SSWs in Southern and Northern polar regions is affected by human activities remains to be studied.

654

Estimation of water contribution from rock glaciers in the Hurtado River sub-basin, Coquimbo region, Chile

Ms(c) Felipe Fuentes¹, Sr. Cristobal Machuca¹, Sr. Luis López¹, Srta. Elizabeth Molina¹, Sra. Paula Olea¹, Srta. Cecilia Donoso¹, Sr. Miguel Ortiz¹, Ms(c) Roberto Nicolas Merino¹, Phd Oriol Monserrat², Phd Ivo Fustos³, Phd Benjamin Robson⁴

¹Sernageomin, Santiago, Chile. ²Thecnological Center of Telecommunications of Catalunyan, Barcelona, Spain. ³University of La Frontera, Temuco, Chile. ⁴University of Bergen, Bergen, Norway

Abstract

To estimate the water contribution of the cryoforms, the methodology used in this project consists of the use of recent technologies such as the use of drones to create high-resolution 3D models, in combination with Differential GPS equipment to adjust the models. at centimetric error resolutions, to be able to compare the models obtained with an approximate time difference of 1 year, in order to obtain the difference in volume in the rock glaciers, and thus correlate the equivalent water that melted in these bodies with the estimates of equivalent water that would be present in the rock glaciers of the Hurtado River sub-basin. These results are accompanied by Geological and Geomorphological cartography for the study area, as well as hydrogeochemical analysis (major, minor and trace elements) and stable isotopes. Samples were taken mainly in supraglacial lagoons, estuaries, a glacier and precipitation collectors. In addition, five gravimetric profiles were carried out, which allowed estimating the thickness of the cryoforms, as well as an analysis of satellite images, using the methodology of differential radar interferometry with permanent scatterers (DInSAR and PSI) to determine the magnitude and speed of displacement of cryoforms.

Finally, the combination of the techniques used has allowed us to estimate the water contribution of the cryoforms, which corresponds to 31.98 l/s per year of contribution from the El Ternero Alto, Quebrada Amarilla rock glaciers and the El Volcán mountain glacier, which is equivalent to 18% of the recharge of the water balance of the Hurtado River sub-basin

657

Integrated Sub-Ice Shelf Observations Beneath Dotson Ice Shelf, West Antarctica

Clare Eayrs¹, Jisung Na¹, Choon-Ki Lee¹, Won Sang Lee¹, Seung-Tae Yoon², Anna Wählin³, Keith Nicholls⁴, David Holland⁵

¹Korea Polar Research Institute, Incheon, Korea, Republic of. ²Kyungpook National University, Daegu, Korea, Republic of. ³University of Gothenburg, Gothenburg, Sweden. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵New York University, New York, USA

Abstract

Modified Circumpolar Deep Water reaching the grounding line under ice shelves plays a crucial role in basal melt and impacts sea level rise by modulating the rate of ice flow into the ocean. The ocean currents below the ice shelves play a dominant role in controlling the temporal and spatial variabilities of ice shelf melt rates. However, the pathways and transformation of water arriving at the grounding zone from the continental shelf are rarely observed and, therefore, poorly understood.

In January 2022, we installed a mooring using a Hot Water Drill to collect the first-ever time series of observations in the ice shelf cavity underneath Dotson Ice Shelf, West Antarctica. During a return in 2024, data was retrieved, and the mooring was refurbished. Our dataset comprises a 5-day time series of currents and water properties (from three nodes located at the ice base, ~100 m from the ice base, and ~700 m from the ice base) and a 2-year time series of water properties at 100 m below the ice shelf. These continuous data are complemented by two spatial snapshots taken from under-ice-shelf AUV missions in January 2022 and January 2024, providing a unique comparative perspective on the sub-ice-shelf cavity conditions.

By integrating our high-resolution mooring and AUV data with broader-scale reanalysis datasets, we provide a comprehensive view of the factors influencing water masses beneath the Dotson Ice Shelf. Our study provides lessons for advancing under-ice shelf observation techniques and contributes to a broader understanding of ice-ocean interactions and their implications for ice shelf stability and global sea level rise.

660

Does Antarctic and Southern Ocean Temperature Affect Indian Monsoon - A Paleoclimatic Perspective

Dr Manish Tiwari, Dr Vikash Kumar

National Centre for Polar and Ocean Research, Vasco-da-Gama, India

Abstract

Most of humanity lives in the monsoon-dominated tropics and sub-tropics, while the maximum effect of recent climate change is happening in the polar regions. This raises the critical question - Does polar climate variability affect monsoons? Short-term observations suggest high-latitude areas affect monsoons but miss low-frequency variability. Paleoclimatic records can help study such low-frequency relationships and offer insight into teleconnections when the earth was in a fundamentally different climate state. Most studies focus on northern high latitudes, overlooking the southern hemisphere's role. To fill this lacuna, we studied the relationship between the South Asian summer monsoon and temperatures of Antarctica and the Southern Ocean on multi-centennial to multi-millennial timescales. We identified the periods of high and low summer monsoon activity by studying oxygen and carbon isotopic ratios of two foraminifera species from a sediment core from the southwestern tropical Indian Ocean spanning the last interglacial and parts of the previous two glacial periods (187 to 41 thousand years before present). We find coherent changes in cross-equatorial summer monsoon flow and Antarctic temperatures: warm (cold) conditions in Antarctica were linked to weak (strong) monsoons. It appears that millennial-scale variability in the southern high latitude region significantly modulates sub-orbital variance of cross-equatorial monsoon flow by influencing temperatures in the tropical Indian Ocean, possibly through isopycnal subduction of high latitude waters. To test this further, we reconstructed the SST from the Indian Sector of the Southern Ocean using trace element ratio analysis of microfossils from marine sediment during the past ~40,000 years. Using this proxy data along with a paleoclimate model (LOVECLIM) data, we find that the SST of the mid-latitudes of the Indian sector of the Southern Ocean controlled the long-term variability of the Indian summer monsoon; colder SST is related to stronger summer monsoon.

663

Application of the YOLOv6 model to automatically count Antarctic shag nests on aerial images

Robert Bialik¹, Katarzyna Fudala¹, Andrew Cusick², Piotr Storożenko², Jędrzej Świeżewski², Joanna Kaleta³, W. Chris Oosthuizen⁴, Christian Pfeifer⁵

¹Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. ²Appsilon, Data for Good, Warsaw, Poland. ³Warsaw University of Technology, Warsaw, Poland. ⁴University of Cape Town, Cape Town, South Africa. ⁵ThiNK, Jena, Germany

Abstract

The Antarctic shag (Leucocarbo bransfieldensis), which has 175 colonies in Antarctica, is known to be a trigger species for 24 of 205 Important Birds and Biodiversity Areas (IBAs) in Antarctica. Our team has been regularly monitoring 6 of the colonies of Antarctic shags located around King George Island at Shag Rock, Turret Point, and Cape Melville and three on unnamed islands using drones since 2019. Two locations (Shag Rock, Cape Melville) were chosen to train the object detection model based on the YOLO architecture and to identify nests on the obtained orthomosaic. To validate the model performance during training, three orthomosaics of Turret Point were used. Our dataset of 6 colonies was used to test whether the resulting model correctly counts nests separated in time. These data were supplemented with orthomosaics from 5 other colonies, one located on Nelson Island (Harmony Point) and four from the northwestern part of King George Island, and all these data were used to test whether the obtained model correctly counted nests that were separated in space. We confirmed that F1 >0.95, which indicates that the proposed model based on the obtained drone images can provide reliable and fast estimates of the number of shag nests. The abundance results for each colony are presented. The results of all tests are also discussed. A website will be presented where the full model code, data and trained model are available to allow full reproducibility of the results. We have shown that machine learning provides a solution to simplify the processing of aerial photographs and allows researchers to analyse larger areas to search for new shag colonies, but we also see opportunities to apply the same model to assess the abundance of, for example, chinstrap penguins, which are seen in the same mosaics that we analysed.

665

Ice and subglacial bedrock drilling project at Princess Elizabeth Land, East Antarctica

Professor Nan Zhang¹, Professor Pavel Talalay^1,2, Professor German Leitchenkov³, Associate professor Da Gong¹, Engineer Yunchen Liu¹, Associate professor Yazhou Li², Doctor Yuchen Sun², Doctor Ilnur Abdrachmanov³, Doctor Mstislav Vorob’ev⁴, Engineer Damir Khalimov³, Associate professor Bing Li², Professor Vladimir Lipenkov⁵

¹Polar Research Center, Institute for Polar Science and Engineering, College of Construction Engineering, Jilin University, Changchun, China. ²China University of Geosciences (Beijing), Beijing, China. ³Institute for Geology and Mineral Resources of the World Ocean, St.Petersburg, Russian Federation. ⁴Institute of Geography of the Russian Academy of Sciences, Moscow, Russian Federation. ⁵Arctic and Antarctic Research Institute, St.Petersburg, Russian Federation

Abstract

Study of subglacial geological environment is a frontier scientific issue of Antarctic research. In 2023, the joint scientific project between Jilin University, China University of Geosciences (Beijing) and VNIIOkeangeologia has been established with the main purpose to study subglacial geology and dynamics of the northwestern part of Princess Elizabeth Land, East Antarctica. The project includes penetrating through Antarctic Ice Sheet and recovering bedrock sample suitable for geological investigations. In the 2023-2024 summer season, the joint research team which consisted of 5 CHINARE and 3 RAE members penetrated through 545 m thick ice sheet by using cable-suspended Ice and Bedrock Electromechanical Drill (IBED) designed by Jilin University and obtained 0.48 m long subglacial bedrock sample. This is the deepest bedrock borehole in East Antarctica up to now. The drilling site was located in the central part of high-amplitude, linear magnetic anomaly. According to the different depth of the formation, different drilling modules were used to adapt to the formation characteristics in snow, firn, glacier ice, brittle ice, and basal ice. The report introduces the progress and performance of ice and subglacial bedrock drilling. The field technical experience is summarized, the causes of the problems and the treatment methods are analyzed.

666

New changes for the Ross Sea Region: the opening up of the fifth Chinese Antarctic Research Station --Qingling

Dr. Yanyan Shan

Polar Research Institute of China, Shanghai, China. Shanghai Maritime University, Shanghai, China

Abstract

On February 7, 2024, Chinese Qingling Station was officially opened at the Ross Sea coastal area of East Antarctica during the 40th Chinese National Antarctic Research Expedition (CHINARE). Qingling Station is China's fifth Antarctic research station and the first to face the Pacific sector. It will conduct multi-sphere and multidisciplinary observation, monitoring, and scientific research in atmospheric environment, basic marine environment, and biological ecology. Once operational, the station is expected to accommodate 80 personnel during the summer season and 30 personnel for overwintering. The Ross Sea region was first discovered by Captain James Clark Ross in 1841. After that it experienced histories of explorers, whalers and territorial claims. Nowadays, Ross Sea region is a significant hub for polar science, with research stations from New Zealand, United States, Germany, Italy, Russia and South Korea. This research aims to evaluate the performance of the Ross Sea region in multi-dimensions under the Antarctic Treaty System, and discuss what kind of geopolitical and governance changes will China's arrival bring.

668

Update on the High-Energy Universe from IceCube

w Jim Madsen

UW-Madison, Madison, USA

Abstract

The IceCube Neutrino Observatory captures light from particles produced from cosmic ray and neutrino interactions to explore the high energy universe. An array of 5160 light sensors has transformed a cubic kilometer of South Pole ice at depths between 1.5 and 2.5 kilometers into a versatile instrument seeing neutrinos with energies that span more than 10 orders of magnitude. IceTop, a square kilometer surface array directly above the in-ice array, serves as a veto for identifying neutrino events and enables a range of cosmic ray science. The annual data set includes roughly 10¹¹ cosmic ray events, 10⁵ neutrinos created by cosmic ray interactions in the Earth's atmosphere, and from astrophysical sources, hundreds of neutrinos of which dozens can be individually identified at the highest energies (>100 TeV). An overview of recent results from each of these data channels will be provided. These include identifying the first steady-state high energy neutrino sources---NGC1068 and the Milky Way Galaxy---and significant advances in measuring the flavor composition of the astrophysical neutrino flux. The large atmospheric neutrino flux and improvements in event selection and reconstruction are producing competitive results for neutrino oscillation parameters and leading limits on the existence of sterile neutrinos. Cosmic ray flux, composition and anisotropy measurement are also progressing. A summary of how these successes motivate the low-energy IceCube Upgrade underway and IceCube-Gen2, a high energy extension in the planning stage, will be given.

671

New high-resolution bathymetry of a future marginal zone of Thwaites Glacier, West Antarctica?

Robert G. Bingham¹, Helen Ockenden¹, Julien A. Bodart², Felipe Napoleoni¹, Rebecca Schlegel³, Andrew M. Smith⁴, Alex M. Brisbourne⁴, International Thwaites Glacier Collaboration GHOST Team⁵

¹University of Edinburgh, Edinburgh, United Kingdom. ²University of Bern, Bern, Switzerland. ³University of Tübingen, Tübingen, Germany. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵GHOST Team, Germany, United Kingdom, USA

Abstract

Thwaites Glacier, identified as West Antarctica’s weakest underbelly, holds an estimated 65 cm of potential global sea-level rise, and is already experiencing dramatic thinning and retreat in its lower reaches. These phenomena have motivated an international consortium of researchers – the International Thwaites Glacier Collaboration – to focus a programme of field-data acquisition on the glacier ultimately to inform modelling projections of the catchment’s future. Two of the key inputs required to improve modelling projections are the shape and rheology of the ice-sheet bed, which formed the focus of the GHOST (Geophysical Habitat of Subglacial Thwaites) project’s programme of geophysical measurements on Thwaites Glacier in the austral seasons 2022/23 and 2023/24.

We present here a new high-resolution view of the bed underlying a 10 km x 80 km patch of Thwaites Glacier sounded by high-frequency ground-penetrating radar (the British Antarctic Survey’s DEep-LOoking Radio Echo Sounder; DELORES). The surveyed site is located from 70 – 150 km upstream of the grounding zone but, crucially, immediately upstream of a feature, GHOST Ridge, which marks a potential point of stability under projected grounding-zone retreat and is also the upstream limit of the highly crevassed terrain that forms the glacier’s lowest reach.

The results show a highly variable and mixed subglacial terrain and we highlight the following. 1) The subglacial landscape is characterised in part by a network of channels which appear fluvial in form and largely match predicted hydrological pathways draining subglacial lakes from upstream; 2) the mesoscale shape of the landscape matches well with its predicted form inverted from the satellite-derived surface elevation and velocity fields; and 3) the basal reflectivity is highly variable, reflecting both the likelihood of a mixed sediment/rock bed and the persistent challenges of incorporating basal slipperiness accurately into modelling parameterisations.

673

An extreme value theory perspective on large iceberg calving events

Dr. Emma MacKie¹, Dr. Joanna Millstein²

¹University of Florida, Gainesville, USA. ²Colorado School of Mines, Golden, USA

Abstract

Large iceberg calving events have become frequent occurrences in Antarctica in recent years, motivating the need to accurately project future calving events. Because the physics is incompletely resolved, data-driven and machine learning approaches are essential for informing projections and improving our understanding of calving processes. However, conventional data science methods are designed to be most effective on the middle of the distribution (i.e. small and medium sized calving events) and have limited predictive capabilities for predicting extreme events. We address this issue by modeling calving events using extreme value statistics (EVS), which is specifically designed to model extreme events. This analysis shows that the likelihood of large calving events has not increased in recent decades. The framework presented here delivers a statistically robust method of estimating large iceberg calving occurring in the absence of a physically-based model. This approach could be built upon to consider physical relationships.

677

Puck-based data transmission using adaptive radio modems for through-ice communications

Victoria Siegel¹, William Stone¹, Veronica Guerrero¹, Jacob Sahli², Albin Gasiewski², Brian Pease¹, Miriam Alexander¹, John Harman³, Corey Hackley³, John Naglak¹, Justin Smith¹

¹Stone Aerospace, Del Valle, USA. ²University of Colorado Boulder, Boulder, USA. ³Scale Free Solutions, Fort Ashby, USA

Abstract

The NASA-funded PARTI-Pucks project advanced through-ice communication technology for a subsurface mission on Jupiter’s moon, Europa, focusing on radio transceivers as a backup communication system. The project evaluated three communication designs: UHF, MF/HF, and HF. Lower RF frequencies are more effective in imperfect ice, especially in colder conditions. VHF/UHF is optimal for Europa’s upper brittle ice layers due to minimized interference from Jupiter's emissions and less attenuation. Deeper in the ice column, warmer ice attenuates VHF/UHF transmission, but MF/HF frequencies persist. The project's goal is to design communication systems optimized for ice depth. In areas with dominant Jupiter noise, VHF/UHF pucks are recommended. As pucks go deeper and the noise decreases, the focus shifts to MF/HF or HF designs.

The MF/HF Dipole Antenna design consists of two insulated wires embedded in a tether. This unusual “end fire” mode uses a quasi-static E field that drops off as distance squared in free space. An in-air test was conducted from a hot air balloon to confirm that this electric field was actually present at 1 km distance at the strength shown in simulations. A circular patch antenna was designed in the VHF/UHF spectrum to optimize puck surface area and thickness. It features orthogonally positioned probes for circular polarization. Simulation software ensured consistent performance in air and ice, and a dielectric matching layer was added to address potential inconsistencies. A crossed-loop antenna was developed in the HF spectrum from 7/8" ferrite rods, forming a 10” by 10” cross. This design, using a 90-degree phase shift network, achieves up/down circular polarization optimized for a 5MHz RF signal. The UHF patch and HF crossed-loop antennas are set for testing through approximately 500 meters of glacier ice in Longyearbyen, Svalbard in March 2024.

680

“How benthic communities respond to environmental gradients in the West Antarctic Peninsula”

Lea Katz¹, Tasnuva Ming Kahn², Henri Robert³, Emily Mitchell², Bruno Danis¹, Camille Moreau¹

¹Université Libre de Bruxelles, Brussels, Belgium. ²University of Cambridge, Cambridge, United Kingdom. ³EMC2, Brussels, Belgium

Abstract

Ecosystems from the Western Antarctic Peninsula (WAP) are challenged by some of the most rapid environmental changes recorded on the planet, especially regarding ice-related processes such as regression in the yearly extent of sea ice, glacier retreats and ice shelves collapsing. These events intensify the already steep environmental gradients present in the WAP, at different spatial scales. To capture responses of benthic communities, we first need to understand what processes structure these communities, at different spatial scales. In this study, we used Bayesian Network Inference (BNI) to delineate the structure of ecosystems, more specifically which are the key taxa in the benthic community’s dynamics, what are the environmental factors that influence directly or indirectly the presence of certain functional/taxonomic groups, and finally, determine what causal relationships exist between all these parameters. Field work in the WAP was carried out using an agile research platform (RV Australis) which allowed us to deploy a Remotely Operated Vehicle (ROV), to generate underwater imagery in shallow areas. The sampling effort followed a nested design, to allow comparing results at various spatial scales. In each image, all organisms were annotated, as well as their size, along with substrate granulometry and algae cover. Other environmental parameters such as depth, water column characteristics and distance to glacier, were recorded in a synchronized manner and added to the analysis. Results showed striking differences in dominant trophic and taxonomic groups, and algae cover, across the different stations and sub-stations. BNI Analysis outlined some key players that could explain these spatial heterogeneities. As expected, the parameters “granulometry” and “presence of parameter" and “distance to glacier” seem to be in a central position in our small-scale model networks, meaning at the scale of a bay.

681

Developing a high-throughput genetic method to elucidate the diversity and abundance of zooplankton from Southern-Ocean Continuous Plankton Recorder (CPR) collections

Georgia Pollard¹, Dr. Matt Pinkerton², Prof. Mary Sewell³, Prof. Moira Décima⁴, Prof. Charles Lee¹, Karen Robinson⁵, Dr. Svenja Halfter², Prof. Craig Cary¹

¹University of Waikato, Hamilton, New Zealand. ²National Institute of Water and Atmospheric Research, Wellington, New Zealand. ³University of Auckland, Auckland, New Zealand. ⁴4University of California, San Diego, La Jolla, USA. ⁵National Institute of Water and Atmospheric Research, Christchurch, New Zealand

Abstract

Zooplankton play essential roles in food webs and biogeochemical cycling in the Southern Ocean. Given the anticipated impacts of climate change, such as warming, ocean acidification, and sea ice reduction, a greater understanding of zooplankton community baseline dynamics is critical to detect shifts, design ecosystem monitoring, and establish ecosystem conservation. Continuous Plankton Recorders (CPRs) are deployed from vessels while underway to enable wide-ranging, long-term, and cost-effective zooplankton collection across the Southern Ocean. However, zooplankton sample processing has traditionally relied upon morphological identification, which requires significant time and specialized expertise, frequently resulting in under-processing and under-analysis of samples. CPR-collected specimens are also often damaged, hindering morphological identification. High-throughput genetic techniques, based on polymerase chain reaction (PCR), can improve the speed and accuracy of analysis. PCR primers effectively targeting areas of high DNA sequence variability across taxa are also essential to reduce the need for group-specific primer sets. To address inconsistent sequence data availability for Southern-Ocean species, we developed a universal DNA extraction protocol and tested multiple primer sets targeting the COI gene and the full 18S ribosomal RNA operon using Sanger and Nanopore sequencing. The protocols were optimized across 9 phyla covering 120+ taxa. Using bongo net and underway specimens identified by a taxonomic expert, we generated reference sequences that will populate a publicly available, Southern-Ocean-specific database and be used to further fine-tune the identification process. This project considers how to address reference sequence database gaps and how to optimize genetics workflows for whole-community zooplankton research questions. Our goal is to develop a high-throughput genetic CPR pipeline. Upon completion, this genetic method should have broad utility, applicable across sampling methodologies and throughout the Southern Ocean.

682

Seismic activity and hazard in Antarctica

Jesus Galindo-Zaldivar¹, Javier Almendros², Simone Cesca³, Masaki Kanao⁴, Rob Larter⁵, Anya Reading⁶, Alessandro Vuan⁷, Douglas A. Wiens⁸

¹Dpto. Geodinámica, University of Granada, Granada, Spain. ²Instituto Andaluz de Geofísica, University of Granada, Granada, Spain. ³GFZ German Research Centre for Geosciences Potsdam, Potsdam, Germany. ⁴National Institute of Polar Research, Tokyo, Japan. ⁵British Antarctic Survey, Cambridge, United Kingdom. ⁶School of Natural Sciences, University of Tasmania, Hobart, Australia. ⁷OGS, National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ⁸Department of Earth and Planetary Sciences, Washington University, St Louis, St Louis, MO, USA

Abstract

Despite its predominantly low seismic activity, Antarctica experiences seismic events primarily driven by tectonic movements near plate boundaries and glacial seismotectonics. Seismicity associated with active plate boundaries is concentrated in regions surrounding the Antarctic Peninsula, Victoria Land, and offshore areas. The largest earthquakes recorded in the region, of Mw 8.1 magnitude, struck the Southern Ocean in 1998 and 2021, the last one resulted in a small tsunami. Additionally, volcanic activity, notably at Mount Erebus and Deception Island, contributes to seismicity. Particularly noteworthy is the Bransfield Strait, exhibiting the highest seismic activity due to the separation of the South Shetland block from the Antarctic Peninsula. This back-arc extension is associated with subduction along the South Shetland trench and sinistral motion between the Scotia and Antarctic plates. Seismicity near the South Orkney Islands is related to strike-slip motion along the Scotia/Antarctic plate boundary, while in Victoria Land, Ross Island, Queen Mary Land and Adélie Land, seismic activity is associated with geological boundaries and glacial processes.

The seismic stations facilitate the characterization of seismic events. Nevertheless, gaps in station coverage necessitate further deployment to enhance detection capabilities. Seismic hazard assessment in Antarctica needs to consider factors such as earthquake magnitude, depth, geological structure, and statistical estimates of the expected ground motion. The seismic risk is influenced by population density, infrastructure quality, and secondary hazards such as landslides and tsunamis. The vulnerability of Antarctic infrastructures to seismic events is particularly pronounced in coastal regions. This underscores the critical importance of developing comprehensive multi-risk hazard analyses that consider not only seismic risks but also other potential threats. Such analyses should evaluate tsunami effects and develop early-warning systems, allowing for proactive measures to protect essential infrastructure. Overall, enhancing seismic monitoring, research, and risk assessment is crucial for safeguarding Antarctic infrastructure and personnel against seismic hazards.

687

Advancements in Bi-directional Cryobot Technology for Antarctica and Beyond

Veronica Guerrero¹, William Stone¹, Victoria Siegel¹, Alberto Lopez¹, Kristof Richmond¹, Ephraim Lanford¹, Bartholomew Hogan¹, Scott Lelievre¹, Justin Smith¹, Nathan Wright¹, John Naglak¹, Antonella Wilby¹, Samuel Weinberg¹, Chris Flesher¹, Neal Tanner¹, James Ralston¹, Mimi Alexander¹, Josh Moor¹, Rachel Price¹, John Harman², Krista Myers²

¹Stone Aerospace, Austin, USA. ²Scale Free Solutions, Fort Ashby, USA

Abstract

The drive to explore beneath the icy surfaces of Earth and the Solar System's icy moons, such as Europa and Enceladus, fuels the advancement of innovative technologies for deep ice drilling. Among these, the Thermal High-voltage Ocean-penetrator Research platform (THOR) and the Vertical Motion Control System (VMCS) offer capabilities for controlled, autonomous penetration through ice and the potential for probe retrieval.

THOR marks a leap forward in cryobot technology, featuring a Closed-Cycle Hot Water Drill (CCHWD) and the novel HOTSHOT heating system. Unlike passive thermal probes, CCHWD doubles the melting efficiency and is also able to penetrate through polar glacial debris. HOTSHOT's design, which allows for resistive heating of conducting fluids under high-voltage, low-current conditions, achieves power densities up to 600 kW/liter. This innovation is key for cryobot missions in environments where nuclear power is not an option. When measured against traditional hot water drills, THOR matches penetration rates with a significantly reduced logistical footprint.

The VMCS project, aimed at future integration with THOR, is a control system for managing the cryobot's vertical navigation capabilities. The deployed trailing tether provides vehicle stability and navigation through obstacles such as voids or water-filled cavities. This bi-directional capability is pivotal for Earth's analog missions, improving the sustainability and impact of Antarctic expeditions by enabling the recovery of valuable probes. VMCS has undergone validation on a testbench, focusing on tether management and stability during descent and ascent, and the current focus is on developing reliable spooling controls for tethers that are both thin (millimeter-sized) and long (kilometer-long) during simulated tension events.

The integration of VMCS with the research platform THOR indicates a significant advancement in the field of ice exploration, setting the stage for groundbreaking interdisciplinary research that spans from Earth's polar regions to the icy moons of the Solar System.

694

Features of the heat balance of snow-ice covers of natural and artificial origin

Features of the heat balance of snow-ice covers of natural and artificial origin Boris Ivanov^1,2, Features of the heat balance of snow-ice covers of natural and artificial origin Andy Bezgreschnov³, Features of the heat balance of snow-ice covers of natural and artificial origin Sergey Poliakov³, Features of the heat balance of snow-ice covers of natural and artificial origin Ekaterina Zotova³, Features of the heat balance of snow-ice covers of natural and artificial origin Nikolay Rudenko³, Features of the heat balance of snow-ice covers of natural and artificial origin Vladislav Punko^3,4

¹Arctic and Antarctic Research Institute, Санкт-Петербург, Russian Federation. ²Saint-Petersburg State University, Saint-Petersburg, Russian Federation. ³Arctic and Antarctic Research Institute, Saint-Petersburg, Russian Federation. ⁴LLS GEOSKAN, Санкт-Петербург, Russian Federation

Abstract

Experimental studies of the characteristics of the heat balance of snow-ice covers of natural and artificial origin were carried out in the area of the runway of an ice airfield on an ice dome in the area of the Russian Antarctic Progress station. Measurements of the short- and long-wave components of the radiation balance, the vertical thermal and radiation structure of the upper radiation-active layer of the ice dome, vertical conductive heat fluxes, snow density and snow stratification were carried out. Vertical turbulent heat fluxes were carried out in the surface layer of the atmosphere using gradient observations. Surface albedo was estimated by unmanned aerial vehicle and ground-true measurements. A comparison of the above values was made by the example of natural and artificial surfaces (runway).

695

Pools and Streams: Flows of Heat and Cold through a Polar Base

Emeritus Professor Susan Roaf¹, Professor Manuel Guedes²

¹Heriot Watt University, Edinburgh, United Kingdom. ²Instituto Superior Técnico, Lisbon, Portugal

Abstract

The quest for achieving Net Zero Bases on Antarctica is highly dependent on how well buildings on bases perform in thermally and functionally, and the amount of energy needed to operate them. This paper presents the findings of a short study undertaken in 2020 of the thermal performance of the living quarters of the Chilean research base, Julio Escudero, on King George Island, Antarctica. The research methods used included a walk-around photographic record of the spaces, a thermal comfort survey of occupants noting their clothing, posture, environmental conditions and comfort perceptions. Measured temperatures over two weeks to shed light on the thermal interactions between climate, building and occupants. A thermal imaging survey highlighted the different ways in which cold penetrated the structures and spaces of the building. A follow-up study in February 2024 studied used monitoring and thermal imaging surveys to explore in more detail the flows and pooling of heat and cold in common spaces. The results of the study were revelatory in identifying the hitherto invisible thermal pathways within the structure, construction and services of the building and resulting from behaviours within it. Heat leakage and wastage resulting from the design and operation of the building led to significant increases in energy usage and greenhouse gas emissions from the base. Designers from warmer, richer and more energy abundant regions may have little understanding of the importance of the patterns of such flows and pooling of heat and cold indoors leading to designs for space and structures that are inappropriate for the extreme Antarctic climate where energy use in, and emissions from buildings are of increasing concern. The paper concludes with suggested actions at the design, refurbishment and operation stages of living and indoor working spaces to improve the thermal performance of bases.

696

Exploring the relationship between STEVE and SAID during three events observed by SuperDARN

Dr Eduardo Perez Macho

Penn State University, State College, USA

Abstract

The phenomenon known as Strong Thermal Emission Velocity Enhancement (STEVE) is a narrow optical structure that may extend longitudinally for thousands of kilometers. Initially observed by amateur photographers, it has recently garnered researchers’ attention. STEVE has been associated with a rapid westward flow of ions in the ionosphere, known as subauroral ion drift (SAID). In this work, we investigate three occurrences of STEVE, using data from one of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) ground-based all sky imager (ASI) located at Pinawa and from the Super Dual Auroral Radar Network (SuperDARN). This approach allows us to verify the correlation between STEVE and SAID, as well as analyze the temporal variation of SAID observed during STEVE events. Our preliminary results suggest that the SAID activity starts before STEVE, and the magnitude of the westward flow decreases as STEVE progresses towards the end of its optical manifestation.

701

Once Upon a Time, in the cold southern Antarctic continent… a scientific fairy tale was written for ocean literacy

Dr. Camila Neder^1,2, Valentina Cherry³, Dr. Rebecca Borges^4,5

¹Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Cs. Exactas Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina. ³Facultad de Cs. Exactas Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Córdoba, Argentina. ⁴Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany. ⁵Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

Abstract

"You don't know what you've got until it's gone"... they say. In a world where understanding scientific concepts is crucial for informed decision-making, effective communication about biodiversity conservation, ecosystem adaptation, and climate change mitigation is critical. The project Once Upon a Time... a Scientific Fairy Tale (OUAT) attempts to bridge the gap between scientific research and public understanding by presenting scientific knowledge in an accessible and engaging manner, particularly targeting children and educators of diverse backgrounds. Marine researchers, illustrators, and educators from diverse cultural backgrounds merge storytelling with science to craft a valuable resource for ocean literacy. OUAT helps to make science accessible across languages for local audiences worldwide and to captivate young minds while enhancing interest in science and its impacts in everyday life. In this study, we showcase the pedagogical aspects of one of the fairy tales about climate change and the Antarctic environment contrasting storytelling with traditional ways of presenting scientific information to younger audiences, such as regular lectures at school. The power of storytelling lies in its ability to contextualize complex concepts and evoke emotional connections. Plumi’s story transports the reader to the soft bottom of Antarctica, with the take-home message of biodiversity responses as distribution shifts or possible losses in response to glacier retreat and increased carbon emissions. By simple terms such as “chocolate river”, the audience integrates scientific concepts such as sediment & meltwater run-off as environmental shifts in responses to climate change, as well as identifying potential threats of species distribution by giving character names that connect to their biological features. OUAT educates inspiring curiosity and empathy towards the natural world by providing excellent tools for home and schools, where educators can enhance their teaching methodologies and motivate participation in STEM. OUAT demonstrates the transformative potential of storytelling in science communication. Happy reading!

702

Sidewall borehole thermal ice corer for glaciers and ice sheets

Xianzhe Wei¹, Pavel Talalay¹, Yazhou Li², Xiaopeng Fan¹, Da Gong¹, Gaoli Zhao³

¹Jilin University, Changchun, China. ²China University of Geosciences (Beijing), Beijing, China. ³Zhengzhou University, Zhengzhou, China

Abstract

To retrieve samples of thin horizontal layers of tephra, basal ice and shearing zones from the existent borehole in glaciers and ice sheets, a kind of sidewall thermal ice corer (STIC) is proposed. Being deployed in drilled ice boreholes of 135-170 mm in diameter, STIC could drill into sidewall of parent hole under maximum rate of penetration of 2 m/h to get approximately 500 mm long ice core samples with diameter of more than 25 mm. Besides retrieving of the core samples, STIC can be used also for installation into the borehole wall temperature, deformation and other sensors. The STIC consists of a driven unit, a bending core barrel and a thermal melting coring head. Bending core barrel stored in drill body could reach out through the wall of drill and push melting coring head installed on end of it into borehole wall. The bending core barrel is flexible and driven by motor on top of the drill for advance and return. Ice core is cut by catchers, broken into pieces by bending core barrel, stored in the drill body and taken to surface together with the whole system by surface winch. To provide high coring precision and degree of freedom, a camera is installed to monitor the targeted depth and a rotating of the structure. In appropriate cases, extra turning motor could be added into the corer design enabling coring tool to drill towards targeted azimuth. The report presents first testing results of STIC in laboratory and also emphasizes further improvements and plans.

708

Deep dives with Chinstrap Penguins: machine learning as a tool to identify prey-capture events from animal-borne data loggers

Dr Stefan Schoombie¹, Dr Lorene Jeantet^2,3,4, Dr Marianna Chimienti⁵, Dr Grace Sutton⁶, Professor Pierre Pistorius⁷, Dr Emmanuel Dufourq^2,3,4,8, Professor Andy Lowther⁹, Dr Chris Oosthuizen¹

¹University of Cape Town, Cape Town, South Africa. ²National Institute for Theoretical and Computational Sciences, Stellenbosch, South Africa. ³African Institute for Mathematical Sciences, Cape Town, South Africa. ⁴Stellenbosch University, Stellenbosch, South Africa. ⁵Centre D’Études Biologiques de Chizé, La Rochelle, France. ⁶La Trobe University, Melbourne, Australia. ⁷Nelson Mandela University, Port Elizabeth, South Africa. ⁸Research and Innovation Centre, Kigali, Rwanda. ⁹Norwegian Polar Institute, Tromsø, Norway

Abstract

Advances in bio-logging technology continually open new opportunities to increase our understanding of animal foraging behaviour. However, quantifying foraging success remains challenging in marine predators such as penguins that forage while diving at sea. Developing new monitoring approaches to estimate prey consumption rates of krill-dependent penguin populations are crucial to aid ecosystem management in the Southern Ocean.

The combined use of bird-borne video loggers and inertial measurement units (IMUs) have shown promise in detecting individual prey captures in free ranging penguins. Previous studies in krill-feeding Adélie penguins attached IMUs to the head and back of penguins, and used thresholds of head-only acceleration as a signal of prey capture events. We used data from single, back-mounted accelerometer-depth loggers (rather than combinations of tags) and neural networks with multiple layers (deep learning) to identify individual prey captures of Antarctic krill (Euphausia superba) in chinstrap penguins.

We fitted 96 chinstrap penguins at two locations in the South Orkney Islands archipelago with loggers recording video, depth and tri-axial accelerometry. We describe an open-source toolbox developed to synchronize and visualize data from all collected sources. The video data were used to identify individual prey capture events (PCE), matched with accelerometer data then used to train two established deep learning models to predict PCE in the absence of video data. We show that both deep learning models were well suited to predict PCE, but balancing of the data beforehand was necessary. Our method can be used on other penguin species to provide more accurate information on prey consumption rates for much longer periods than currently possible with video loggers. Importantly, as our approach is likely transferrable across penguin species and captures data through relatively inexpensive tri-axial accelerometry devices, it is also likely to be a cost-effective means to improve and update current marine ecosystem monitoring efforts.

709

Characterizing the temporal variability in the spatial distribution of suitable habitat for microbial mats in Fryxell basin in the McMurdo Dry Valleys, Antarctica

Khum Thapa-Magar¹, Eric Sokol², Michael Gooseff¹, Mark Salvatore³, John Barrett⁴, Joseph Levy⁵, Paul Knightly³, Sarah Power⁶, Morgan Wood⁷

¹University of Colorado, Boulder, Colorado, USA. ²NEON, Battelle, Boulder, Colorado, USA. ³Northern Arizona University, Arizona, USA. ⁴Virginia Tech University, Blacksburg,Virgina, USA. ⁵Colgate University, Newyork, USA. ⁶Virginia Tech University, Blacksburg, Virginia, USA. ⁷Virginia Tech University, Blacksburg, Virgina, USA

Abstract

Remote sensing tools offer incredible potential to monitor spatial and temporal trends in biodiversity. Specifically, satellite-based platforms can provide relatively high-frequency, spatially explicit data sets over a long time period that can be used for ecological monitoring. In this study, we used a time series of high-resolution multispectral imagery for species distribution modeling (SDM) process and characterized the annual and seasonal variability of the distribution of black microbial mat habitat in Fryxell Basin of McMurdo Dry Valleys in Antarctica. To run SDM models, we ran spectral unmixing models on surface reflectance data from WorldView & imagery to create a timeseries of spatially explicit species occurrence records. Then, we employed additional spectral unmixing and classification techniques to derive environmental variables, including snow cover and soil moisture, from the same imagery. Additionally, we included three time-invariant topographical variables to account for spatial heterogeneity: elevation, slope, and aspect. We then fit SDMs to generate a time series of habitat suitability maps for black microbial mats. Temporal variability in the habitat suitability maps shows significant inter-annual and seasonal variation in hotspots for mats. Specifically, expected hotspots of mat occurrence based on habitat suitability was concentrated around the Lake Fryxell, edges of glaciers, and edges of ephemeral streams. Interestingly maps of suitable microbial mat habitat showed high inter-annual variability in the high elevation regions surrounding Fryxell Basin. Water-related environmental variables like soil-moisture appear to be the primary predictor variables for black mat distribution.This study provides an important view of annual differences in key ecological properties and their relationship to observed black mat habitats. In addition, we provide the groundwork for automated temporal species distribution models using remotely observed data and highlight the importance of temporal aspects in species distribution modeling for better monitoring of the organisms and predicting their suitable habitat with changing climate scenarios.

712

The US State Department and Antarctica during the government of Jimmy Carter, 1977-1981

Mr Nelson Llanos

Universidad de Playa Ancha, Valparaiso, Chile. Centro de Estudios Hemisfericos y Polares, Viña del Mar, Chile

Abstract

Transition from détente to a more intense confrontation between Washington and Moscow characterized the global context during late 1970s and early 1980s. In the Antarctic sphere also arose new issues that could impact the Antarctic Treaty System. Some of them were a growing international pressure for the exploitation of mineral resources and the existing tension between Chile and Argentina due to a border dispute that involved territories and maritime spaces near the frozen continent. Considering the implications that these new challenges could have for Washington, this paper analyses the US State Department’s role in Antarctic politics during the administration of James Earl Carter Jr. By examining official documentation issued by the Department (reports, correspondence, memorandums) this work specifically aims to identify and understand the main concerns and interests of the US government regarding Antarctica and the southern seas between 1977 and 1981.

714

Ancient diversification in extreme environments: Exploring the historical biogeography of the Antarctic winged midge Parochlus steinenii (Diptera: Chironomidae).

Dra Claudia Maturana¹, Dra. Tamara Contador^2,3, Dr. Felipe Simoes⁴, Dr. Moises Valladares^5,6, MSc Melisa Gañán^2,3,7, Dr. Claudio González-Wevar^8,9, Dr. Elie Poulin¹, Dr. Chester Sands⁴, Dr. Peter Convey⁴

¹Instituto Milenio BASE, Santiago, Chile. ²Instituto Milenio BASE, Puerto Williams, Chile. ³Centro Internacional Cabo de Hornos, Puerto Williams, Chile. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Laboratorio de Biología Evolutiva, Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. ⁶Grupo de Biodiversidad y Cambio Global (GBCG), Departamento de Ciencias Básicas, Universidad del Bío-Bío, Chillán, Chile. ⁷FEHM-Lab (Freshwater Ecology, Hydrology and Management), Departamento de Biología Evolutiva, Ecología i Ciencias Ambientales, Facultad de Biología, Universidad de Barcelona, Barcelona, Spain. ⁸Instituto de Ciencias Marinas y Limnológicas (ICML), Centro FONDAP IDEAL, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ⁹Instituto Milenio BASE, Valdivia, Chile

Abstract

The terrestrial fauna of Antarctica consists of a limited number of species, notably insects, small crustaceans and other micro-invertebrates. Over long periods of evolutionary isolation, these organisms have developed varying degrees of tolerance to multifaceted environmental stresses. Parochlus steinenii, commonly known as the Antarctic winged midge, stands out as one of the only two insect species native to Antarctica. Distributed across three biogeographic regions, southern South America and the Falkland/Malvinas Islands, sub-Antarctic South Georgia and the Maritime Antarctic South Shetland Islands, this midge raises questions about the temporal isolation of its populations and their divergence. Employing mitochondrial and nuclear genetic markers, we conducted phylogeographic and demographic analyses on 151 individuals of P. steinenii obtained across the three main biogeographic regions including the Magellan sub-Antarctic Ecoregion (MSE) of southern South America, the sub-Antarctic Island of South Georgia (SG) and the South Shetland Islands within the Maritime Antarctic (MA). Our data support the diversification of P. steinenii during the mid-Pleistocene around 1.46 Mya. This period included a branching event between a clade containing only specimens from the MSE and a clade containing individuals from a broader range of locations including the SSI and SG. Based on intraspecific phylogeographic and demographic inferences, we detected strong evolutionary divergence between the three main biogeographic regions. We also detected a signal of population growth during the deglaciation process in SSI and SG, contrary to the pattern seen in the MSE. The different demographic and phylogeographic histories between the sampled biogeographic regions could arise since MA and SG experienced a strong genetic bottleneck due to a reduction in population size during the last glacial period, while the MSE maintained a significant effective population size. The high level of divergence detected between MSE and the remaining biogeographic regions supports the hypothesis of a speciation process in P. steinenii.

715

Spatiotemporal evolution of sea ice and its teleconnections with large-scale climate indices over Antarctica

Ms Swathi M, Dr Avinash Kumar, Dr Rahul Mohan

National Centre for Polar and Ocean Research, Vasco Da Gama, India

Abstract

Sea ice variability patterns in Antarctica are highly influenced by several large-scale ocean-atmospheric oscillations. We have demonstrated the influence of large-scale ocean-atmospheric oscillations on sea ice variability in Antarctica using statistical and wavelet coherence methods. Over the past 42 years (1979-2020), the total extent of Southern Ocean sea ice extent has expanded, while the sea ice extent (SIE) of the Amundsen-Bellingshausen Sea (ABS) has decreased. Based on our analysis, El Nino Southern Oscillation (ENSO) has a greater impact on variation in the Antarctic sea compared to other parameters such as Indian Ocean Dipole (IOD) Southern Annular Mode (SAM), and Interdecadal Pacific Oscillation (IPO). A wavelet coherence analysis (WCA) of ENSO and SIE in various sectors revealed an out-of-phase correlation between the Indian Ocean and the Ross Sea, revealing a decrease in SIE with a positive phase of ENSO. The influence of SAM on sea ice variability has expanded in recent years and is now more significant than the influence of ENSO in these sectors. It has been observed that the SAM index and SIE are associated with a dipole pattern, with more ice in the Ross Sea and less ice in the Weddell Sea. We have also observed changes in sea ice characteristics following the phase shift of IPO from positive to negative after the 1990s. Given the widespread global impacts of climate change on Antarctic sea ice, we could underscore the importance of understanding the interplay between large-scale climate indices and sea ice for predicting and adapting to climate change.

717

A new perspective: Using environmental data collected from Animal-Borne Instruments (ABI) deployed on central-place foragers to investigate long-term trends in the coastal Southern Ocean environment

Dr Luis Huckstadt^1,2, Dr Rachel Holser², Daniel Skeats¹, Dr Theresa Keates², Dr Christophe Guinet³, Prof Mark Hindell⁴, Dr Clive McMahon⁵, Dr Andrea Pinones⁶, Dr Michael Goebel²

¹University of Exeter, Penryn, United Kingdom. ²University of California Santa Cruz, Santa Cruz, USA. ³CNRS, Chize, France. ⁴University of Tasmania, Hobart, Australia. ⁵IMOS Animal Tagging, Sydney, Australia. ⁶Universidad Austral de Chile, Valdivia, Chile

Abstract

Coastal ocean environments have been identified as regions that, despite their biological importance and high susceptibility to anthropogenic activities, remain data-deficient due to the difficulties that traditional oceanographic sampling platforms have to operate in these high-energy systems. The processes that dominate coastal waters are particularly complex in high latitudes, where ice (sea ice and land glaciers/ice sheets) and persistent high winds play a determinant role in the structure and dynamics of these environments. Oceanographic data are routinely collected by diving air-breathing species outfitted with animal-borne instruments (ABI) used as Lagrangian sampling platforms. However, ABI deployed on central-place foragers that come back to a colony can help fill a crucial gap in coastal observations as multiple individuals sampling a relatively small section of the coastal oceans can be seen as Eulerian sampling platforms. We focus on two large sets collected in the South Shetland Islands (Western Antarctic Peninsula) by Antarctic fur seals (1997 – 2014, n = 497) and Kerguelen Island (Indian sector of the Southern Ocean) by Southern elephant seals (2008 – 2019, n = 123). All data were georeferenced using the manufacturer’s GPE3 light-based geolocation State Space Model algorithm (Wildlife Computers, USA) and diving depths were zero-offset corrected. The data were binned in 0.25° of latitude and longitude and daily, weekly and yearly average temperature and light intensity vertical profiles were calculated. Finally, these datasets were used to assess multi-scale variability and trends in temperature of the water column, mixed layer depth, and light penetration. This is the first step in a potential long-term, multinational effort to create a platform to formally incorporate these ‘ghost’ datasets into the Southern Ocean observations toolset.

719

Ecological processes underlying climate-driven shifts in Antarctic benthic assemblages

Biol. María Piotto^1,2, Dr. Teresa Morán-López^3,4, Dr. Leonardo A. Saravia^5,6, Dr. Cristian Lagger^1,2, Biol. Luciana A. Ferrero^1,2, Dr. Carla de Aranzamendi^1,2, Dr. Camila Neder^1,2, Dr. Ricardo Sahade^1,2

¹Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina. ³Departamento de Biología de Organismos y Sistemas (Universidad de Oviedo), and Instituto Mixto de Investigación en Biodiversidad (Universidad de Oviedo-CSIC- Principado de Asturias), Oviedo, Spain. ⁴Grupo de Ecología Cuantitativa, INIBIOMA-CONICET, Universidad Nacional del Comahue, Bariloche, Argentina. ⁵Laboratorio de Ecología y Sistemas Complejos, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Centro Austral de Investigaciones Científicas (CADIC), Ushuaia, Argentina. ⁶Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur, Ushuaia, Argentina

Abstract

Climate-driven factors as ice-scouring and sediment discharge affect coastal ecosystems of the Antarctic Peninsula. Both factors vary with Climate Change altering the structure of benthic communities. In 1998, after a peak in sedimentation rates, benthic assemblages of Potter Cove (South Shetland Islands) shifted from an ascidian-dominated towards a mixed one. To infer the underlying assembly mechanisms, we analysed temporal trends of the benthic community using joint species models. Genera’s occupancy and their cover when present were obtained from photo transects performed at 15-20 m and 25-30 m in 1994, 1998 and 2009. Both variables were modelled as a function of the depth and the year, and the phylogeny and functional traits of the genera. The traits included were: habitat use (epibenthic vs. interphase-epibenthic), feeding strategy (filter feeders vs. non-filter feeders), and reproductive strategy (brooder vs. broadcaster). Frequent ascidians like Molgula sp., Corella antarctica and Ascidia challengeri, decreased its occupancy (on average 4.56 times) and cover when present (1.38 times) from 1994 to 2009. In contrast, Malacobelemnon daytoni became more widespread (2.93 times) and abundant (1.17 times). Regarding other guilds, Ophionotus victoriae and Serolis sp. increased their occupancy, similarly to many rare species (80 % of them). Shifts in assemblage composition were more intense in deep than in shallow areas and were mediated by traits. Filter feeders were the most widespread organisms in 1994, whereas in 2009 non-filter feeders became more common. Additionally, the impact of reproductive strategies and habitat use on the structure of the assemblages weakened over time. Beyond measured traits, the phylogenetic signal was high. Our results evidence a decreasing occurrence and cover of filter feeders in deep areas, which are being colonized by non-filter feeders. Furthermore, the reduced effect of the other traits on the assemblage structure suggests a deepening of shallower communities as a consequence of Climate Change.

722

Simultaneous modelling of horizontal and vertical movement patterns of Humpback whales in the Southwest Atlantic and Southern Oceans

Luis Bedriñana-Romano^1,2,3, Alexandre Zerbini^4,5, Artur Andriolo^6,5, Federico Sucunza⁵

¹Centro Ballena Azul, Valdivia, Chile. ²Centro de Investigación Oceanográfica COPAS Coastal, Universidad de Concepción, Concepción, Chile. ³Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile. ⁴Cooperative Institute for Climate, Ocean and Ecosystem Studies, University of Washington and Marine Mammal Laboratory Alaska Fisheries Science Center/NOAA, Seattle, USA. ⁵Instituto Aqualie, Juiz de Fora, Brazil. ⁶Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil

Abstract

Diving metrics derived from biologging are increasingly available for many marine mammal species, thus complementing behavioral assessments on their horizontal paths. In rapidly changing ecosystems such as the Southern Ocean, understanding complex behavioral responses to environmental shifts is paramount for understanding possible population-level effects. Here we use data from satellite-linked tags with diving profilers deployed in 11 humpback whales from 2017-2023. A two-step hierarchical movement modelling approach was implemented to account for imperfect observation, path regularization, and behavioral state estimation for all whales simultaneously (first step). This yielded behavioral state estimations and true location estimates at observed and user-defined regular time intervals, along with posterior distributions that can be used to recalculate locations placed on land or other known barriers to movement. After this, the effect of environmental variables was simultaneously assessed on horizontal behavioral state switching probability and diving metrics, maximum dive depth (MDD) and dive duration (DD), explicitly accounting for behavioral state context and interindividual variation (second step). Pareto smoothed importance-sampling leave-one-out cross-validation (PSIS-LOO) was used for purposes of model checking and model comparison. Model outputs were used to generate three-dimensional predictions on how whales use their feeding grounds around South Georgia, the South Sandwich Islands, and surrounding waters. The effect of environmental variables on MDD and DD of individual humpback whales varied depending on their horizontal behavioral state. Our preliminary results provide a modelling framework that takes advantage of a “divide and conquer” modelling strategy. Major computational demands are conducted once (first step) with outputs that can be used in diverse subsequent model structures, integrate a diverse array of biologging data, and straightforward procedures for alternative model evaluation.

725

Unravelling Cenozoic climate evolution of the Antarctic Peninsula

Karlos G. D. Kochhann^1,2, Leslie M. E. Manríquez³, Rodrigo M. Guerra^1,4, Gerson Fauth^1,2, Bruna C. Schneider², Rodrigo S. Horodyski², Alessandra S. Santos¹, Lilian M. Leandro¹

¹Technological Institute for Paleoceanography and Climate Change (itt OCEANEON, UNISINOS University), São Leopoldo, Brazil. ²Geology Graduate Program, UNISINOS University, São Leopoldo, Brazil. ³Laboratorio de Paleobiología de Antártica y Patagonia, Instituto Antártico Chileno, Punta Arenas, Chile. ⁴Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil

Abstract

Cenozoic climate evolved from a greenhouse climate state, punctuated by hyperthermal events, to an icehouse state, with permanent glaciation of Antarctica. However, it is still unknown how regional climate of the Antarctic Peninsula, and palaeoceanographic settings of its surrounding shallow seas, responded to these events, which are mostly recognized in deep ocean sedimentary archives. Here we present high-resolution geochemical and paleontological records of shallow marine sedimentary strata exposed on the Antarctic Peninsula. These records are interpreted in the framework of well-constrained age models, and span the Paleocene to Eocene interval on Seymour Island, and the Oligocene time interval on King George Island. We mostly used high-resolution sediments elemental ratio records measured with x-ray fluorescence, such as Fe/K (hydroclimate and weathering intensity proxy), Zr/Rb (sediments grain size proxy) and Ca/Fe (terrigenous input versus carbonate production proxy), to reconstruct paleoenvironmental settings. During Paleocene global warming events, our records suggest the occurrence of drier hydroclimate conditions, and/or reduced chemical weathering intensity, over the Antarctic Peninsula. This trend is supported by palynological records of pollens and spores across selected stratigraphic intervals, and it was particularly clear for the Late Danian Event (LDE), a set of hyperthermal events that occurred between 62.6 and 62.0 Ma. Currently, we are applying the same proxies along Eocene and Oligocene sedimentary successions to reconstruct regional climate across the transition from the greenhouse to the icehouse climate state. [PROANTAR: 442676/2018-2]

726

Antarctica and Africa: Extractive Pasts, Climate Futures

Dr Charne Lavery

University of Pretoria, Pretoria, South Africa

Abstract

This paper presents part of a handbook chapter, synthesizing aspects of the limited but significant research and cultural production on the relationship between Antarctica and Africa. The paper discusses firstly southern Africa’s history as a base for whaling and oil exploration in Antarctic waters, and secondly the two continents’ conjoined futures in a time of climate change, showing how these extractive pasts and climate futures are connected. The first part considers the use of geological pasts, in particular the Gondwana supercontinent, in both resource debates and political imaginaries, as well as the ways in which South Africa’s whaling history is referenced in novels like Laurens van der Post’s The Hunter and the Whale and Zakes Mda’s The Whale Caller. The second part is focused on the representation, in recent South African speculative fiction, of the southmost African coastlines submerged as a result of the melting of Antarctic glacier ice. Mohale Mashigo’s short story, “Floating Rugs”, and Alistair Mackay’s It Doesn’t Have to be This Way portray the southern African coastline as swamped by rising seas, while drawing connections between Africa and Antarctica through other species on the one hand and proximity on the other. The paper forms part of the background research for the South African Antarctic Artists and Writers pilot programme.

729

An invading ecosystem engineer, the potential impacts of the fly Eretmoptera murphyi in the maritime Antarctic

Prof Peter Convey^1,2,3,4, Dr Jesamine Bartlett⁵, Dr Scott Hayward⁵

¹British Antarctic Survey, Cambridge, United Kingdom. ²Department of Zoology, University of Johannesburg, Johannesburg, South Africa. ³MI-BASE Biodiversity of Antarctic and Sub-Antarctic Ecosystems, Santiago, Chile. ⁴CHIC Cape Horn International Center, Puerto Williams, Chile. ⁵School of Biosciences, University of Birmingham, Birmingham, United Kingdom

Abstract

Around 15 species of non-native plants and invertebrates are currently known to be established in the maritime Antarctic. Amongst these the flightless and parthenogenetic chironomid midge, Eretmoptera murphyi, palaeoendemic to sub-Antarctic South Georgia, was accidentally introduced to maritime Antarctic Signy Island during the 1960s. After two to three decades of persistence, since the mid-1990s its local distribution has expanded rapidly. The detritivorous larvae inhabit moss peat, a common habitat on the island, and currently have a two-year life cycle. Population densities approach 100,000 ind. m^-2, with biomass considerably greater than the entire native micro-invertebrate community. Decomposition is currently a rate limiting process in the maritime Antarctic; rates achieved in the presence of high densities of E. murphyi larvae are almost an order of magnitude greater than those achieved by the entire native invertebrate community. The presence of the species leads to a three- to five-fold increase in available nitrate in soils. Distribution modelling indicates that E. murphyi is already capable of considerably expanding its regional distribution. Larval salinity tolerance may facilitate transfer via local marine currents in the South Orkney and South Shetland Islands and western Antarctic Peninsula. Effective biosecurity measures are required to ensure that further human-assisted transfer both on Signy Island and beyond is avoided.

730

Collaboration in the Face of Current Geopolitics and Conflict

Prof Peter Convey

British Antarctic Survey, Cambridge, United Kingdom. Department of Zoology, University of Johannesburg, Johannesburg, South Africa. MI-BASE Biodiversity of Antarctic and Sub-Antarctic Ecosystems, Santiago, Chile. CHIC Cape Horn International Center, Puerto Williams, Chile

Abstract

The sheer geographic scale, environmental extremes, costs and practicality drive the need for collaboration in the polar regions, especially Antarctica. This collaboration is required across continental and trans-oceanic scales and traditional disciplinary boundaries. On top of this, the extreme demand and competition for funding means that today’s science has to be ‘globally relevant’. The central role of the polar regions in the Earth System is well appreciated, and collaboration has been integral to large-scale research in Antarctica in the ‘scientific era’ since the 1957/8 International Geophysical Year, never more so than today! In both polar regions, large multi-institute, multi-nation and multi-disciplinary initiatives are the norm, although collaborations come in all shapes and sizes. However, in an era of short-term funding and career uncertainty, finding out how to become involved, and then to stay involved, can be daunting to those early in their careers. Understanding the ‘landscape’, at local, national and international scales, within which researchers, their institutions and communities operate is a key and career-spanning element of developing successful and influential collaborations. In both Arctic and Antarctic, increasingly complex and negative geopolitical forces have come to prominence in recent years and, sadly, science is not the main driver. However, science (through ‘science diplomacy’) has always provided a means of circumventing some of the higher level politics. This presentation will give a personal perspective, based on three decades of working in polar research and particularly within the international SCAR community, of the importance of and opportunities for productive and long-term interactions.

731

Reconsidering Antarctic Marine Bioprospecting Governance in Light of the BBNJ Agreement

Hope Elizabeth Tracey

University of Waterloo, Waterloo, Canada

Abstract

Marine bioprospecting in the Southern Ocean has attracted considerable attention due to the unique genetic resources thriving in its extreme environments. In the absence of an explicit regulatory framework for marine bioprospecting under the Antarctic Treaty System (ATS), Antarctic marine bioprospecting has been loosely governed by default rules from various international legal agreements such as the United Nations Convention on the Law of the Sea, the Convention on Biological Diversity, and the Agreement on Trade-Related Aspects of Intellectual Property Rights. This arrangement has created a complex regulatory landscape [regime complex] for Antarctic marine bioprospecting, characterized by stability despite normative fissures concerning benefit-sharing, resource ownership, intellectual property, data-sharing, the science-commerce interface, and environmental protection. Stability has been maintained through ambiguity, as there has been no substantial external or internal pressure for the Antarctic Treaty Consultative Parties (ATCPs) to take definitive positions on key interpretive questions. However, in 2023, the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement was reached, containing explicit provisions concerning the governance of activities surrounding marine genetic resources. The BBNJ, unlike other legal agreements, takes clear stances on interpretive questions related to marine bioprospecting, challenging the ambiguity that the ATCPs have relied upon for stability in this governance area. Instead of seeking to harmonize regulatory requirements and processes, the ATCPs have instead sought to isolate themselves from international legal developments, affirming that the ATS is the “appropriate framework” for managing marine bioprospecting in the region. The objective of this presentation is to analyze existing ATS provisions and their compatibility/divergence with the principles and objectives of the BBNJ Agreement, initiating a seemingly avoided conversation about harmonizing these two governance regimes to ensure the conservation and sustainable use of Antarctic resources.

733

Expedition VRctica: Engaging Rural and LatinX Communities in Polar Research

Associate Professor Kevin Ponto¹, Director David Gagnon¹, Dr. Jim Madsen¹, Dr. Monae Verbeke², Resaercher Ross Tredinnick¹, Assistant Professor Diego Roman¹

¹UW-Madison, Madison, USA. ²Inst. for Innov. Learning, Beaverton, USA

Abstract

We describe an ongoing project to work with rural librarians, bilingual science communicators, polar scientists, and a technical team to create a series of five bilingual virtual reality (VR) experiences, engaging users as polar explorers of exotic and extreme environments to enhance STEM understanding and appreciation. Each of the five VR experiences will focus on a different area of research, using the captivating Arctic and Antarctic environments as a central theme to convey science. VR is a particularly powerful and apt approach, making it possible to visit places that most cannot experience first-hand while also learning about the wide range of significant research taking place in polar regions. The first experience, Discover IceCube, takes users on a magical journey from the South Pole, site of the IceCube Neutrino Observatory, to a black hole that is the source of the high energy neutrino detected by IceCube. The second, Waddle, a Penguin’s Tale, allows users to assume the identity of a penguin to playfully experience the challenges and triumphs of life in Antarctica. The third, which is in the testing phase, has users travel to a remote weather station in Antarctica to perform maintenance and repairs while learning about the goals of the research. We report on outcomes of these virtual reality applications and their potential as a vehicle for promoting informal learning and on our experiences in engaging diverse communities. Following in the theme of open science, we will also share the data produced by these experiences, inviting secondary analysis.

735

Wintertime Antarctic krill swarms offer elevated energy density to predators in the Gerlache Strait

Rachel Kaplan, Dr. Kim Bernard, Abby Tomita

Oregon State University, Corvallis, USA

Abstract

During winter along the Western Antarctic Peninsula (WAP), Antarctic krill (Euphausia superba) move inshore to shelter under sea ice and access food resources in protected bays and fjords. In the productive Gerlache Strait, predators including fish, seals, penguins, and whales rely upon krill to build their own energy reserves for the sparse winter season. In this study, we investigated the quality of wintertime Antarctic krill as prey by integrating active acoustic survey data (Simrad EK80), mid-water trawl samples, and caloric analysis to quantify krill abundance, swarm biomass, and the energy density of swarms in the Gerlache Strait during June 2022. These data reveal the broad spatial distribution and high densities of Antarctic krill within the Gerlache Strait and surrounding bays, as well as important characteristics of fine-scale swarm structures formed by krill in these areas (i.e. swarm height, horizontal length, depth within the water column depth, etc.). Integrating trawl-derived Antarctic krill length frequencies and caloric measurements allow quantification of the winter calories, i.e. the energy density, available to krill predators in the Gerlache Strait. Winter is an under-studied time of year in the WAP region, and Antarctic krill and their predators are experiencing increased pressure from both anthropogenic climate change and concentrated inshore krill fishing during this time. Our findings shed light on the winter ecology of this essential ecosystem link in the WAP region, resolve key metrics for estimating predator diet and energetics, and provide information that can be used in ecosystem-based management efforts for both Antarctic krill and their predators.

739

Evolution of the Princess Elizabeth Land, East Antarctica: a collation of heavy minerals and detrital zircons across marine sediments, moraines, and exposed sedimentary outcrops

Dr MAYURI PANDEY¹, MR AKASH PANDEY¹, DR DEVSAMRIDHI ARORA², DR RASHMI GUPTA¹, PROF NARESH PANT^3,4

¹BANARAS HINDU UNIVERSITY, Varanasi, India. ²UNIVERSITY OF ALLAHABAD, PRAYAGRAJ, India. ³NATIONAL CENTRE FOR POLAR AND OCEAN RESEARCH, GOA, India. ⁴UNIVERSITY OF DELHI, NEW DELHI, India

Abstract

Geophysical techniques have revealed the topography and structure of the Gamburtsev Subglacial Mountains (GSM) present in the interior of the Princess Elizabeth Land (PEL) sector. The history and composition of these mountains are deduced from the isotopic and geochemical analyses of zircon found in exposed rocks, morainal deposits and offshore sediments from present and past drainage systems originating from the GSM, particularly within the Lambert Rift.

Detrital zircons retrieved from offshore sediments, morainal samples, and exposed rock formations from PEL display a significant age range, spanning from 3100 Ma to 2750 Ma, 2450 Ma, 2100 Ma, and 890–700 Ma, with subsequent intervals of 700–575 Ma. This variability suggests a complex depositional history characterized by multiple stages and diverse sources contributing to the detrital zircons. This comprehensive review collates published data as well as novel data generated from heavy minerals and detrital zircons across marine sediments, moraines, and exposed outcrops to enhance our understanding of provenance evolution in the PEL Sector. The GSM emerged as the principal source for sediment transportation, particularly during the Gondwana formations and subsequent periods. However, the transportation from GSM is not justified for a few locations with older detrital zircons for interpretations of sedimentary basins. The extensive extent of the Indo-Australo-Antarctic suture (IAAS) adds complexity to understanding the depositional conditions within the interior of the PEL sector. It remains uncertain whether the presence of IAAS and GSM indicates a simultaneous event or if they are associated with different tectonic events. The amalgamation of detrital zircon age data and heavy mineral compositions enhances the robustness of sedimentary record interpretations, elucidating the influence of tectonic and climatic forces that have sculpted the Princess Elizabeth Land Sector over time. This review highlights the recent advancements in understanding the "source-to-sink" connection of the GSM and IAAS to PEL.

744

Farther In, Farther Out… And Almost There—engaging project communications and staying nimble during a deep-field Antarctic science expedition

Marlo Garnsworthy^1,2, Ceridwyn Roberts³

¹University of Nebraska, Lincoln, Lincoln, USA. ²Icebird Studio, Wellfleet, USA. ³Ceridwyn Science Communication, Wellington, New Zealand

Abstract

Capturing, engaging, and motivating a broad, diverse audience—including policymakers, interested parties, the next generation, and the general public—with easily understood, scientifically accurate, and compelling information about Antarctic melting is an enormous challenge. It’s an exciting challenge for a tiny team responsible for communications and education/outreach for an international scientific drilling project—one that takes place 1,000 kilometers from Scott Base & McMurdo Station, a cutting-edge mission with uncertain first-season outcomes due to the groundbreaking nature of the project. Add an unexpected level of live communications capabilities and lots of video material from our deep-field site, which had us almost there with the team in real time!

In this standalone follow-up to our SCAR SC-HASS 2023 presentation Farther In, Farther Out—Reaching the World with a Multi-faceted Outreach Strategy, we explore our Communications and Education & Outreach strategy for SWAIS2C (Sensitivity of the West Antarctic Ice Sheet to 2° Celsius). This highly ambitious, international, multi-expedition scientific drilling project aims to understand whether the success of the Paris Climate Agreement will prevent the collapse of the Ross Ice Shelf. Now, after our first drilling season, we discuss how the comms team stayed nimble and adapted to enhanced communications capabilities, as well as the challenges and triumphs of sharing cutting-edge science at an Antarctic deep-field site. What worked best for communications with the on-ice team? What best engaged the public and the media? What exciting material are we working on as our next season approaches?

745

Correlation between Antarctic sea ice variability in the Weddell Sea, South Atlantic Subtropical High and precipitation in Brazil

Msc Rafael César Silva Silva¹, Professor Francisco Eliseu Aquino²

¹Centro Polar e Climático, INCT da Criosfera, Geography, Graduate Program in Geography, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Centro Polar e Climático, INCT da Criosfera, Geography, Graduate Program in Geography, Universidade Federal do Rio Grande do Su, Porto Alegre, Brazil

Abstract

Antarctic sea ice is the portion of the Southern Ocean that remains frozen, and its variability is an important component of the region's ocean-atmosphere interaction. Frozen seawater around the Antarctic continent inhibits heat exchange, potentially affecting westerly winds and precipitation in remote regions through teleconnections. In this study, observed data on sea ice concentration (SI) in the Weddell Sea (60°W to 20°S) and mean sea level pressure (MSLP) obtained through reanalysis in the climatological region of the South Atlantic Subtropical High were used (SASH, located at 38° S to 20° S and 38° W to 10° E) and precipitation observed via satellite in Brazil (74°W to 34°W and 34°S to 5°N) for Empirical Orthogonal Function analysis (EOF). Analyzing during the months of September, October, and November (austral winter, months of greatest SI extension) in the years 1981 to 2022, the first and second principal components of the SI in the Weddell Sea have a negative correlation with the third principal component of the MSLP of SASH (-0.44 and -0.38) and with the first and second principal components of precipitation in Brazil (-0.31 and -0.34). The first two normalized SI principal components were used to select the years of high and low SI concentration in the Weddell Sea. In years of low (high) concentration, we have negative precipitation anomalies in the north and center (south) of Brazil, while we have negative (positive) MSLP anomalies in the southern branch of SASH. These results indicate that SI concentration anomalies are part of the variability of the Southern Ocean and may have the capacity to affect systems that distributes precipitation in Brazil.

746

Southern Ocean Observing System for sustained and coordinated observations in a changing world

Dr Alyce Hancock¹, Dr Sian Henley², Dr Irene Schloss³, Dr Julia Bach¹

¹Southern Ocean Observing System (SOOS), Hobart, Australia. ²University if Edinburgh, Edinburgh, United Kingdom. ³Instituto Antártico Argentino, Centro Austral de Investigaciones Científicas, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina

Abstract

Over the last decade, significant efforts have been undertaken to enhance our understanding of the Southern Ocean and its impacts on the Earth system. However, this region remains one of the most poorly observed regions on Earth, and there are many uncertainties in estimates of future states and the flow on consequences for the Earth system. This chronic lack of observations was highlighted in a recent community statement released from the SOOS Symposium 2023, calling for a sustained and coordinated Southern Ocean observing system to provide an understanding for current conditions, inform predictions of future states, and support policies and regulations for the benefit of society. The Southern Ocean Observing System (SOOS) is a coordinating body established in 2011 to enhance and ensure the delivery of Southern Ocean data across nations, organisations, programmes, and stakeholders, and to provide the infrastructure for organisation of community networks to develop sustained observing systems and syntheses of existing Southern Ocean datasets. To achieve the SOOS mission and to focus scientific efforts, 5-year strategies were developed by the Southern Ocean community which are outlined in the SOOS Science and Implementation Plan. The long-term vision for SOOS is to have a coordinated multidisciplinary program integrating cutting-edge autonomous platforms and novel approaches with traditional observing techniques to readily deliver “essential” data to stakeholders, including real-time information.

747

Population genomics of Antarctic toothfish: exceptions to panmixia

Dr. Jilda Alicia Caccavo^1,2, Dr. Larissa Souza Arantes^3,4, Dr. Camila Junqueira Mazzoni^3,4

¹Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France. ²Laboratoire d'Océanographie et du Climat Expérimentations et Approches Numériques, LOCEAN/IPSL, UPMC-CNRS-IRD-MNHN, Sorbonne Université, Paris, France. ³Berlin Center for Genomics in Biodiversity Research, Berlin, Germany. ⁴Leibniz Institute for Zoo and Wildlife Research, Department of Evolutionary Genetics, Berlin, Germany

Abstract

Antarctic toothfish (Dissostichus mawsoni) are top fish consumers and key prey species for whales and seals throughout the Southern Ocean. In addition to their importance to bentho-pelagic ecosystems, they support the most lucrative fishery in the Antarctic, worth hundreds of millions of US dollars annually. Precautionary management of the fishery by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) requires knowledge of toothfish population dynamics.

The last several years have seen a blossoming interest in Antarctic toothfish population dynamics, with several international teams contributing research to test life-history connectivity hypotheses. Using reduced-representation genomics methods, in addition to traditional genetics methods involving nuclear and mitochondrial markers, these studies have largely supported the null hypothesis of pamixia across regional and circumpolar scales.

In this presentation, I will share preliminary results of a recently completed, multi-year study combining reduced-representation with the pioneering use whole-genome resequencing methods to understand Antarctic toothfish population structure on in the Weddell Sea and on a circumpolar scale. While our research largely supports the hypothesis of a single, panmictic metapopulation of Antarctic toothfish throughout the Southern Ocean, notable exceptions to this result will be explored, including indications of population heterogeneity between cohorts, indicative of changes in gene flow over time.

750

How Climate Genomics can help predict distribution shifts in Southern Ocean species exposed to environmental change

Dr. Jilda Alicia Caccavo^1,2, Dr. Francesco d’Ovidio², Dr. Marion Gehlen¹

Abstract

Antarctica is experiencing climate change impacts at a rapid clip, resulting in warming trends and increased environmental variability. Estimating the ecological impact of climate change is an unprecedented challenge that drives the emergence of novel cross-disciplinary studies. Recently, the potential for genomics to address climate change impacts on species has come to the fore. This burgeoning field, referred to as climate genomics, combines genomics with environmental data to identify spatially heterogeneous adaptation and genetic structure patterns to understand and predict species distributions. In this presentation, I will introduce the main tools of climate genomics, genotype-environment association (GEA), and genetically-informed species distribution modelling (gSDM), and how we are applying these to understand climate change impacts on Antarctic toothfish (Dissostichus mawsoni). Antarctic toothfish are a commercially exploited top predator in the Southern Ocean, whose early-life stages are vulnerable to the environmental perturbations caused by climate change due to their strong association with sea ice and life history connectivity via surface circulation. In addition to providing critical data to inform the long-term management of Antarctic toothfish, this work develops an innovative, cross-disciplinary approach to studying the ecological impacts of climate change on Southern Ocean species.

752

What environmental factors are driving genomic adaptation in Antarctic toothfish?

Dr. Jilda Alicia Caccavo^1,2, Dr. Francesco d’Ovidio², Dr. Marion Gehlen¹

Abstract

Antarctic toothfish (Dissostichus mawsoni) are a commercially exploited top predator in the Southern Ocean. Their early-life stages are vulnerable to the environmental perturbations caused by climate change due to their strong association with sea ice and life history connectivity via surface circulation. The emerging field of climate genomics provides us with tools to understand the extent to which toothfish may be undergoing adaptive processes in their genome in response to a changing environment. Through the use of genotype-environment association, we can associate markers of functional variation in the genome, proxies of adaptation, with pertinent environmental variables. Given the particular vulnerability of early-life stages, we chose environmental variables that would most likely influence early-life survival of toothfish, including sea surface temperature, sea-ice concentration, salinity, chlorophyll-a concentration, and surface water velocities. Furthermore, because only samples of toothfish adults are available, we approximated early-life exposure by estimating birth years and using data from the environmental variables of interest from those years. In this presentation, I will share preliminary results on the environmental factors linked to adaptive processes in the genome of toothfish, as well as how we intend to use these data to model current and future distributions.

754

Climate change and tsunami vulnerability. Orcadas Argentinian base, Laurie Island, South Orkneys

Lic. Alejandro Emmanuel Celli

Servicio Geológico Minero Argentino, Buenos Aires, Argentina

Abstract

The Argentinian base Orcadas is the oldest permanent base in Antarctica, been in continuous operation for the last 120 years. It is stablished at about 3 meters above sea level in a tectonically complex zone, where the six plates converge. This makes it prone to receiving tsunamis from multiple sources. The largest recorded event occurred in 2003, caused by a Mw 7.6 seism 10 km deep and 75 km ENE from the base. Most of the energy was dissipated by the sea ice surrounding the island, reaching the coast with a very low intensity. Similar situations have occurred over time, with sea ice acting as a good protection for most time of the year. This is evidenced by the fact that the base has not suffered any damage throughout its history.

However, in recent years the duration of sea ice has been significantly reduced, appearing to be a general trend, generating concern about the vulnerability of the base.

In this situation, a geological and geomechanical study was proposed in order to select a suitable site for a shelter that could be accessed in case of a tsunami warning.

The results suggest the feasibility of building a safe shelter for all staff at any time of the year. However, the poor internet connectivity, particularly during the summer, when the population increases significantly, along with the likelihood of sea ice melting, inhibits the immediate implementation of a reliable early warning system with real-time response capabilities, given the proximity of potential sources.

Therefore, as an alternative measure, the relocation of the dormitories to an elevated site, at least during periods without sea ice, has been considered. This decision, not free of logistical complications, highlights the complexity of decision-making in an environment where difficulties have existed, but tsunamis have not been one of them.

755

Sensitivity of climate and ocean circulation to West Antarctic Ice Sheet extent in past interglacials

Dr Elizabeth Keller^1,2, Dr Stefan Jendersie², Prof Nicholas Golledge², Prof Richard Levy^1,2, Frank Mackenzie²

¹GNS Science, Lower Hutt, New Zealand. ²Victoria University of Wellington, Wellington, New Zealand

Abstract

Earth system models often have difficulty reproducing the warmth of past interglacials, particularly at the polar regions. CO₂ concentrations and orbital configurations do not by themselves reproduce regional climate for interglacial periods such as Marine Isotope Stage (MIS) 5e, 11, and 31. In particular, simulated sea surface temperatures in the Southern Ocean are often cooler than proxy records would suggest. The West Antarctic Ice Sheet (WAIS) extent is a key source of uncertainty. Here we use an intermediate complexity model, UVic ESCM, to simulate three different climate/orbital forcings (pre-industrial, MIS 31 / 1.07 Ma, mid-Pliocene warm period / 3.2 Ma), each with three different ice sheet configurations (present-day, WAIS absent, and an in-between state) and compare to paleoclimate ice core and sediment proxy data to evaluate their consistency. Model outputs are then used as boundary conditions for high-resolution regional ocean model simulations with ROMS to explore in more detail the impact of differences in climate and ice sheet extent on circulation around the Antarctic continent. Changes in ice sheet extent alone result in Southern Ocean surface warming in some sectors but overall cooling of the water column at depth. Global meridional overturning circulation (MOC) is also affected, demonstrating that changes in ice sheet extent have unexpected global implications. These experiments offer insight into the sensitivity of global and regional temperatures and ocean circulation to the interactions among atmospheric CO₂ concentration, orbital forcing, and Antarctic ice sheet extent.

757

Plausible Last Interglacial Antarctic ice sheet changes do not fully explain Antarctic ice core water isotope records

PhD Huiling Zou^1,2,3, Dr Louise Sime², Professor Nancy Bertler¹, Dr Liz Keller¹, Professor Eric Wolff⁴

¹Victoria University of Wellington, Wellington, New Zealand. ²British Antarctic Survey, Cambridge, United Kingdom. ³GNS Science, Wellington, New Zealand. ⁴University of Cambridge, Cambridge, United Kingdom

Abstract

Antarctic ice cores can help determine ice mass loss from the Antarctic Ice Sheet (AIS) during past warm periods. We compile Last Interglacial (LIG) δ¹⁸O measurements from eight Antarctic cores. The preindustrial to 127 ky and peak LIG East Antarctic core-mean differences are +1.5 ‰ and +3.3 ‰. Comparing these ice core data to new isotope-enabled LIG simulations, which explore three plausible LIG AIS elevation and extent scenarios, show that these simulations tend to capture less than 10% of the coremean differences. Although our plausible AIS change simulations do not fully explain the core-mean East Antarctic water isotope changes, they do explain some of the intercore geographical patterns of LIG δ¹⁸O changes. This work demonstrates that LIG simulations likely need to include the influences of reduced Antarctic sea ice, a warmer Southern Ocean, and resultant shifts in vapour source regions to produce a more satisfactory core-mean match to core data.

760

Increased awareness of the importance of hydrogeology and groundwater in Antarctica

Dr. Rogier Westerhoff¹, Dr. Simon Cox², Dr. Jess Hillman³, Dr. Sarah Seabrook⁴

¹GNS Science, Wairakei, New Zealand. ²GNS Science, Dunedin, New Zealand. ³GNS Science, Wellington, New Zealand. ⁴NIWA, Wellington, New Zealand

Abstract

Recent research has revealed the potentially significant role of groundwater in critical environmental and climate processes in Antarctica. Yet awareness is low and key details remain unclear, with a severe lack of underpinning data to constrain the origin of water, flow pathways across the Antarctic continent, and global influence on sea level rise.

In association with the development of an Antarctic water cycle diagram (see abstract by Cox et al. 2024), we determine where and how groundwater processes are playing a significant role. Key research questions largely fall under four main themes of: ice sheet dynamics, carbon cycling, ecosystem function, and the global water cycle/balance.

Key research questions, each with a sub-topics list, are:

How significant is the groundwater and solutes component of the Antarctic water budget?
How will climate change impact groundwater processes, and the impact of groundwater on Antarctica’s critical processes?
How do we derive water balance, fluxes and flows that include groundwater with best acceptable uncertainties in Antarctic catchments?

We propose that this research be framed through the overarching question: "What is the capacitance of Antarctica to generate, store and circulate groundwater and could this be significant in the context of local impacts and global sea level rise?" This would encompass questions such as: What happened when freezing conditions last started on the continent? What water and solute volumes, if any, do we expect to be released when the temperatures on the continent increase? Where will this occur?

Addressing the many hydrogeological unknowns that still require discovery, and their limited awareness, we propose to set up a SCAR Action group ‘Developing a continent-wide overview of groundwater and hydrogeology’. This group should aim to compile existing, and obtain new and novel, data and models, facilitating research to respond to these research questions.

761

Aq2: A refined geothermal heat flow map of Antarctica from multivariateobservables for application to ice sheet modelling

Tobias Stål^1,2, Felicity S. McCormack^3,4, Anya M. Reading^1,2, Magued Al-Aghbary^5,6, Jacqueline A. Halpin^7,2, Derrick Hasterok⁸, Mareen Lösing^9,10, Jason L. Roberts¹¹, Hélène L. Seroussi¹², Ross J. Turner^1,2, Joanne M. Whittaker^7,2

¹School of Natural Sciences (Physics), University of Tasmania, Hobart, Australia. ²Australian Centre for Excellence in Antarctic Science (ACEAS), Hobart, Australia. ³School of Earth, Atmosphere & Environment, Monash University, Clayton, Kulin Nations, Australia. ⁴Securing Antarctica's Environmental Future (SAEF), Clayton, Kulin Nations, Australia. ⁵Institute of Geophysics and Geoinformatics, TU Bergakademie, Freiberg, Germany. ⁶Geophysical Laboratory, Centre d’Etudes et de Recherche de Djibouti, Djibouti, Djibouti. ⁷Institute for Marine and Antarctic Studies, Hobart, Australia. ⁸Department of Earth Sciences, University of Adelaide, Adelaide, Australia. ⁹School of Earth Science, Perth, Australia. ¹⁰Australian Centre for Excellence in Antarctic Science (ACEAS), Perth, Australia. ¹¹Australian Antarctic Division, Kingston, Australia. ¹²Dartmouth Collague, Hanover, NH, USA

Abstract

Geothermal heat can play a crucial role in ice sheet basal processes, potentially influencing the stability of the interior regions of the Antarctic Ice Sheet. Historically, Significant discrepancies exist in various models due to method choices and available data. However, recent advancements in multivariate analysis and empirical methods have helped reconcile these differences, resulting in more consistent outcomes that now serve as reliable inputs for ice sheet models. Despite this progress, challenges persist, with some areas still exhibiting significant uncertainty. Notably, the resolution of the heat flow map is a key factor in understanding how basal melt affects ice sheet dynamics.

Aq2 is a heat flow model based on multivariate input data tailored specifically for consistent continental-scale Antarctic investigations. This model not only aids in refining ice sheet simulations but also enhances our comprehension of subglacial geology. Developed using the empirical similarity approach, it incorporates 18 updated observables and an improved weighted reference database. Compared with Aq1, Aq2 leads to significantly reduced uncertainty and improved robustness. The model resolution is refined using a forward approach to redistribute the heat transfer to a 0.5 x 0.5 km grid.

The model is shared as an open-source resource in interoperable formats, complete with uncertainty metrics and accessible code for reproduction.

763

Exploring the impacts of the details of simulating early life stage behavior on Antarctic krill connectivity across the West Antarctic Peninsula

Ms Zephyr Sylvester¹, Dr. Kim Bernard², Dr. Mike Dinniman³, Dr. Cassandra Brooks¹, Dr. Sally Thorpe⁴

¹University of Colorado Boulder, Boulder, USA. ²Oregon State University, Corvallis, USA. ³Old Dominion University, Norfolk, USA. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

To examine the movement of larval Antarctic krill (Euphausia superba) between and within key spawning areas of the West Antarctic Peninsula (WAP), we are modeling Lagrangian drifters to simulate transport pathways during early life stages. The simulated drifters are embedded within a 1.5-km horizontal resolution updated regional WAP implementation of the Regional Ocean Modeling System (ROMS). The model includes tidal forcing, and has 24 vertical terrain-following layers, dynamic sea ice and simulates interactions between floating ice shelves and the underlying waters. The drifters include simplistic behavior of the early life stages of krill including the initial descent/ascent cycle, diel vertical migration (DVM), variable embryo sizes, and advection with simulated sea ice velocity (instead of ocean velocity) under certain conditions. High resolution models enable more detailed investigations of the mechanisms associated with this transport. Here, we explore the sensitivity of transport pathways on and near the continental shelf to (i) the vertical rates in the initial descent based on embryo size, and (ii) the timing of the introduction of sea ice advection. The results are compared to the same experiments run on a circumpolar scale, 5 km resolution ROMS model. Winters with extensive sea ice cover have been linked to high post-larval recruitment the following spring, which suggests that sea ice plays an important role in larval overwinter survival. This work explores the potential connections between spawning grounds and overwinter habitats to better elucidate our understanding of larval abundance along the WAP. We elaborate on implications for krill connectivity, including how the Commission for the Conservation of Antarctic Marine Living Resources might consider krill connectivity in their ongoing efforts for their revised krill fishery management approach and krill stock hypothesis.

764

Baseline records of sea ice and phytoplankton in the Ross Sea Marine Protected Area: biomarker evidence from marine and ice cores over the past 200 years

Holly Winton¹, Emma de Jong¹, Angela Bahamondes-Dominguez², Xavier Crosta³, Johan Etourneau³, Caroline Holmes⁴, Alison Ming⁵, Sebastian Naeher⁶, Peter Nichols⁷, Osamu Seki⁸, John Turner⁴

¹Victoria University of Wellington, Wellington, New Zealand. ²Center for Advanced Studies in Arid Zones, Coquimbo, Chile. ³University of Bordeaux, Bordeaux, France. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵University of Cambridge, Cambridge, United Kingdom. ⁶GNS Science, Wellington, New Zealand. ⁷CSIRO, Hobart, Australia. ⁸Hokkaido University, Hokkaido, Japan

Abstract

Dramatic and unpredictable changes in sea-ice over the last decade have been compounding the still poorly quantified impacts on phytoplankton. The past 200 years provide a critical ecological baseline of natural variability in phytoplankton and sea-ice microalgae in the Ross Sea Marine Protected Area (RSMPA) to contextualise recent change. A few decades of satellite imagery track sea-ice and phytoplankton biomass, but satellite imagery cannot tell the whole story. Phytoplankton biomass and their composition change seasonally, and in response to changing sea-ice conditions. Information on how sea-ice conditions drove seasonal phytoplankton blooms beyond the satellite era can be extracted from well-dated marine and ice core records.

We present a novel approach to reconstructing past sea-ice and phytoplankton change using ice core biomarkers. Fatty acids and their carbon isotopes (δ¹³C-C16 fatty acids) measured in an array of ice cores surrounding the RSMPA reflect seasonal changes in phytoplankton blooms and their composition (diatoms and Phaeocystis antarctica) in proximal polynyas. We compare the phytoplankton biomarkers to sea-ice trends in the Ross Sea over the past 200 years from independent records of ice core water isotopes and a new sediment record based on sea-ice diatoms and highly branched isoprenoid hydrocarbons (HBI) biomarkers from the SW Ross Sea. The general trend of sea-ice change in the Ross Sea agrees between records, whereby sea-ice cover increased from 1880 to 1950, declined between 1950 and 1990, and subsequently increased. However, fatty acid and HBI biomarkers reveal spatial variability in the Ross Sea likely related to seasonal changes in individual polynyas. This highlights the need for a spatial array of ice core fatty acid records in the RSMPA to provide baseline constraints on sea-ice and marine phytoplankton blooms, to advance knowledge of the natural state of the RSMPA ecosystem, and to improve our understanding of regional climate variability.

766

A new underwater vehicle (Glider) for studying the oceanographic characteristics in the Subantarctic and Antarctic zone

Lorena Rebolledo¹, Francisco Santa Cruz¹, César Cárdenas^1,2, Juan Pablo Jorquera³, Lucas Krüger^4,2

¹Chilean Antarctic Institute (INACH), Punta Arenas, Chile. ²Instituto Milenio Base, Santiago, Chile. ³Servicio Hidrográfico y Oceanográfico de la Armada Chilena (SHOA), Valparaíso, Chile. ⁴Chilean Antarctic Institute (INACH), Santiago, Chile

Abstract

The glider is an autonomous, unmanned underwater vehicle utilized for gathering oceanographic data in remote locations. It offers a cost-effective solution with extended operational durations, typically lasting at least 30 days depending on sensor configurations and battery endurance.

The Chilean Antarctic Institute (INACH) and the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA) have approved a proposal for the acquisition of an autonomous underwater glider, funded by the Chilean Research and Development Agency (ANID) through FONDEQUIP. Equipped with a suite of sensors including CTD, oxygen sensor, fluorometer-turbidity, and ADCP, the glider will be initially deployed in Subantarctic waters of the Magellan Strait in December 2024, with subsequent deployments planned for the Antarctic region during the 2026 season.

The glider will offer invaluable support to researchers participating in the Chilean Antarctic Science Program (PROCIEN) and projects focused on Antarctic oceanography, ecology of top predators, and fisheries. We welcome researchers from other Antarctic National Programs interested in collaborating on projects related to ecology and oceanography.

772

New ice core proxy for reconstructing past wind variability in the Pacific sector of the Southern Hemisphere Westerly Wind belt

Dr Dieter Tetzner, Dr Elizabeth Thomas, Dr Claire Allen

British Antarctic Survey, Cambridge, United Kingdom

Abstract

The Southern Hemisphere Westerly Winds play a critical role in the global climate system by modulating the upwelling and the transfer of heat and carbon between the atmosphere and the ocean. Since observations started, the core of the westerly wind belt has increased in strength and has contracted towards Antarctica. It has been proposed that these deviations are among the main drivers of the observed widespread warming in West Antarctica. However, the lack of long-term wind records in the Southern Hemisphere mid-latitudes hinders our ability to assess the wider context of the recently observed changes.

Here, we present multiple records of diatoms preserved in a set of ice cores retrieved from the Antarctic Peninsula and Ellsworth Land region, Antarctica. The diatom abundances and species assemblages from these ice cores represent the regional variability in wind strength and atmospheric circulation patterns. We use this novel proxy to produce an annual reconstruction of winds in the Pacific sector of the Southern Hemisphere Westerly Wind belt over the last 400 years. This wind reconstruction allows tracking changes in the strength and position of the westerly winds during the Little Ice age and exploring the link between the recent increase in wind strength, greenhouse gases and ozone depletion in the atmosphere.

773

The first firn core from the Cordillera Darwin Icefield: Assessing the preservation of paleoenvironmental information.

Dr Dieter Tetzner¹, Dr Elizabeth Thomas¹, Dr Claire Allen¹, Dr Amy Mcguire², Dr Delia Segato³, PhD (c) Dorothea Moser¹, Dr Francisco Fernandoy⁴, Dr Camilo Rada⁵

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of Leeds, Leeds, United Kingdom. ³University of Venice, Venice, Italy. ⁴Universidad Andres Bello, Vina del Mar, Chile. ⁵Universidad de Magallanes, Punta Arenas, Chile

Abstract

In recent decades, glaciers have been shrinking worldwide in response to increasing surface temperatures, contributing significantly to sea level rise. The impact of climate change on glaciers has been widely observed along the entire South American Andes, but particularly in the icefields of Patagonia and Cordillera Darwin. Despite their relevance, only the icefields from Patagonia have been widely studied. The Cordillera Darwin icefield has remained mostly uncharted.

The Cordillera Darwin icefield is located in an isolated region in the southernmost mountain range in the South American Andes. In 2020, as part of a National Geographic funded expedition, we drilled the first ice core in this icefield. This shallow depth ice core provides unprecedented records from this region. Here we present our results applying several analytical methods, including: continuous flow analysis (CFA), laser ablation inductively-coupled plasma mass spectrometry (LA-ICPMS), scanning Electron Microscopy (SEM), High-resolution ion chromatography (IC), cavity-ring down spectroscopy (δD and δ18O), line scanning, and microfocus X-ray computer tomography. These results allow us to assess the potential of the ice from this icefield to hold records of past environmental variability. Firn analyses are complemented with back trajectory analyses and climate reanalyses to track aerosol/moisture sources and to determine how exposed the icefield has been to surface melt conditions, respectively. Our results confirm paleoenvironmental records can be retrieved from the icefield high-elevation sites which are currently threatened by increasing surface air temperatures.

777

Did the Ronne ice shelf suddenly retreat during the Last Glacial-Interglacial Transition? New evidence from diatoms preserved in ice cores

Dr Dieter Tetzner¹, Dr Elizabeth Thomas¹, Dr Claire Allen¹, Professor Eric Wolff²

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of Cambridge, Cambridge, United Kingdom

Abstract

Recent modelling studies suggest significant mass loss and rapid collapse of the West Antarctic Ice Sheet (WAIS) has occurred in the past, making recent predictions that anthropogenic warming could lead to a loss of the WAIS in the next few centuries particularly alarming. However, major uncertainties exist regarding the past and future stability of the WAIS and its ice shelves. To better predict the fate of the WAIS under future warming scenarios, we must first determine how stable is the ice sheet and its ice shelves in response to forcings. This can be achieved by using accurate paleoclimatic records during past climate transitions.

The Last Glacial-Interglacial Transition (LGIT), 20,000-6,000 years ago, is an ideal period to assess the relationship between climate, ice sheets and sea level. Recent results from Skytrain ice core suggest the Ronne ice shelf, the second largest ice shelf in Antarctica, presented a considerable retreat during the early Holocene, in response to the changing environmental conditions.

Here, we present a 25-year resolution diatom record from the Skytrain ice core during the LGIT. The diatom diversity in Antarctic ice cores closely represents the proximity of the nearest open water source. Antarctic coastal domes present diatom assemblages dominated by locally sourced sea ice species. This contrasts with the diatom diversity observed at inland sites, which are dominated by open ocean species indicating long-range transport. We use these characteristic signatures to track past changes in the proximity of the nearest open water source, providing new evidence to support the proposed sudden retreat of the WAIS during the LGIT, causes and timing.

781

Extinction risk assessment for the Antarctic Flora: The Antarctic plant red list initiative.

DR Paulo Camara^1,2, DR Eduardo Amorim³, Srta Brenda Emerick¹, Bsc. Maria Clara Laydner¹, DR Micheline Silva¹

¹Universidade de Brasilia, Brasilia, Brazil. ²Universidade Federal de Santa Catarina, Florianopolis, Brazil. ³Jardim Botanico do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Red lists are the results of risk assessments that highlight species with the greatest potential for extinction. They are tools used to inform and influence political and legislative decision-making at national or international levels; stimulate research and monitoring; programs for species and/or habitats; monitor the state of biodiversity and the state of the environment; regulate the development and exploitation of natural resources; target geographic areas for conservation planning; increase public awareness of human impacts on biodiversity; and assist in defining priorities for the allocation of conservation resources. The Antarctic flora, comprising approximately 116 mosses, 27 liverworts, and two native angiosperms, has yet to undergo assessment regarding its risk of extinction. This is particularly crucial given that climate change impacts the region, escalating human activities (including tourism), and the constant threat of invasive species, all serve as primary pressures on the local biodiversity. Additionally, the likely ineffective protection of Antarctic plant species, coupled with its flora consisting of endemism and rarities, poses significant challenges to species conservation. Our objective is to compile an updated list of Antarctic flora alongside their conservation status, adhering to the criteria and categories outlined by the IUCN. So far, seven bryophyte species have been evaluated: Coscinodon lawianus (LC), Schistidium lewis-smithii (DD), S. steerei (DD), S. leptoneurum (DD), S. deceptionense (DD), Roaldia revoluta (VU), and Bryum pseudotriquetrum (VU). These findings represent the first steps in assessing the extinction risk for Antarctic flora and emphasize the urgent need to gather more information on Antarctic species to ensure comprehensive and robust risk assessments.

783

Estimating net community production in Antarctic sea ice

Laura Dalman^1,2, Florian Deman³, Klaus Meiners^2,4,5, David Thomas⁶, Sophie Bestley^1,2, Matt Corkill¹, Bruno Delille⁷, Agneta Fransson⁸, Alexander Fraser², Julie Janssens⁹, Delphine Lannuzel^1,5, Sebastien Moreau⁸, Christina Schallenberg^2,9, Jean-Louis Tison¹⁰, Martin Vancoppenolle¹¹, Pier van der Merwe¹, François Fripiat¹²

¹Institute for Marine and Antarctic Studies, Hobart, Australia. ²Australian Antarctic Program Partnership, Hobart, Australia. ³Vrije Universiteit Brussel, Brussels, Belgium. ⁴Australian Antarctic Division, Department of Climate Change, Energy, the Environment and Water, Kingston, Australia. ⁵Australian Centre for Excellence in Antarctic Science, Hobart, Australia. ⁶Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, Finland. ⁷Unité d’océanographie chimique, FOCUS, Université de Liège, Liège, Belgium. ⁸Norwegian Polar Institute, Tromsø, Norway. ⁹Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart, Australia. ¹⁰Université Libre de Bruxelles, Brussels, Belgium. ¹¹Laboratoire d'Océanographie et du Climat (LOCEAN), Institut Pierre-Simon Laplace (IPSL), Paris, France. ¹²Department of Geosciences, Environment and Society, Université Libre de Bruxelles, Brussels, Belgium

Abstract

Antarctic sea ice is one of the largest ecosystems on Earth, most of which consists of annual pack ice, which contains various habitats for sea-ice algae to grow and fix carbon dioxide into biomass. Sea-ice biogeochemical models suggest that Antarctic pack ice contributes to a small but significant fraction of the primary production in the ice-covered area of the Southern Ocean. Actual measurements of primary production in Antarctic sea ice remain scarce and an observational estimate of primary production has not been revisited in over 30 years. A historical ice core dataset of particulate and dissolved organic carbon from 362 ice cores sampled between 1989 and 2019 was used to place observational constraints on sea-ice net community production. Our estimate of 26.8-32.2 Tg C year^-1 accounts for 13-15% of the total primary production in the Antarctic sea-ice zone, and is in remarkable agreement with model estimates.

784

Exploring the Icy Depths: Macroplastics Across South Shetland Islands

Engineer Karen Portilla^1,2, Doctor Franco Teixeira de Mello³, Master Elizabeth Velarde¹, Master Tania Oña¹, Master Santiago Cabrera¹, Master Gabriel Jácome¹, Engineer Verónica Condo-Espinel⁴, Master Evelyn Krojmal³, Master Barbara Barbara De Feo³, Doctor Gissell Lacerot³, Proffesor Janna Asselman⁵, Proffesor Colin Jansen⁵, Doctor Juan Pablo Lozoya³

¹Grupo de Investigaciones Antárticas (GIAN), Universidad Técnica del Norte, Ecuador, Ibarra, Ecuador. ²Carrera de Recursos Naturales Renovables, Facultad en Ciencias Agropecuarias y Ambientales (FICAYA), Universidad Técnica del Norte, Ibarra, Ecuador. ³Centro Universitario Regional del Este (CURE), Universidad de la República, Maldonado, Uruguay. ⁴Laboratorio de Microplásticos (SHOIAR), Instituto Oceanográfico y Antártico de la Armada, Guayaquil, Ecuador. ⁵Environmental Toxicology Unit-GhEnt ToxLab, Ghent University, Ghent, Belgium

Abstract

Plastic pollution, ranging from macroplastics to microplastics, has become ubiquitous across our planet, extending its reach to even the most remote areas, such as Antarctica. To assess the prevalence of macroplastics (items> 5mm) on South Shetland Island, samples were collected systematically from several areas of the islands of Greenwich, Robert, Barrientos, and Dee. The survey covered beaches and rocky areas during February-March 2023. Based on transect surveys along the coast (10 m width/person), sampling points (5 m radius surface) were defined by the naked eye detection of at least one plastic debris. Plastics were quantified, measured, weighted, and classified based on CCAMLR marine debris categories supplemented by an additional subcategory, fragmented plastic. During our study, 569 macroplastics items were collected, with Greenwich yielding 399, Robert 71, Dee 96 and Barrientos 3. Fragmented plastic emerged as the predominant subcategory, accounting for 32% in Greenwich, 82% in Robert and 38% in Dee. Styrofoam appeared as the second common item, accounting for 22% in Greenwich, 13% in Robert and 9% in Dee. Both fragmented plastic and Styrofoam were absent from Barrientos. These items subcategories varied in size from 0.3 to 235 cm. Other items, such as bags, cups, lids, straws, open ropes, and open strapping bands were also found. Barrientos exhibited the lowest microplastic density with 0.1 items/100m², while Dee recorded the higher density with 6.4 items/100 m². Greenwich and Robert displayed 1 and 1.5 items/100 m², respectively. The varying densities of macroplastics among the islands suggest differences in local environmental factors, waste management practices, and human activities influencing pollution levels. These findings highlight the urgent need for targeted interventions to mitigate macroplastic pollution in the studied islands. Furthermore, continued monitoring and research efforts are essential for understanding the dynamics of plastic pollution and informing conservation initiatives to preserve ecosystem health

786

Unprecedented changes at Perito Moreno Glacier. What do they mean?

Dr. Lucas Ruiz¹, Dr. Pierre Pitte¹, Dr. Antoine Rabatel², Dr. Etienne Berthier³, Dr. Mariano Masiokas¹, Mg. Lidia Ferri¹, Ing. Juan Cruz Ghilardi Truffa¹, Lic. Lautaro Clavero¹

¹IANIGLA, Mendoza, Argentina. ²IGE, Grenoble, France. ³OMP LEGOS, Toulouse, France

Abstract

Climate change is affecting all regions of the planet. In the Patagonian Andes, the Southern Patagonian Ice Field, the largest body of ice in the Southern Hemisphere outside Antarctica, lost mass between 2000 and 2020 at one of the fastest rates in the world. However, not all the glaciers of the ice field behave similarly.

The Glacier Perito Moreno (GPM) has remained stable since 1917, when its front came into contact with the Magellan Peninsula, after an advance of more than 1 km in the early 20th century. Since then, GPM has had an oscillatory behavior, advancing and generating the blockage of the Tempanos channel and the spectacular breaks that have made it world-famous. Between 2000 and 2020, different studies agree that the glacier was close to equilibrium. However, since 2020, a significant retreat was observed on the northern margin of its front.

To understand the processes behind the Perito Moreno glacier's mass changes between 1976 and 2023, we modeled ice and snow melting and snow accumulation, computed frontal ablation, and parametrized its morphological changes. We calibrate the model with previous and novel ablation and accumulation measurements.

On average, the annual mass change between 1976 and 2023 was neutral. However, between 2015 and 2023, the longest period of high mass loss rates of the last 47 years developed. In the last 47 years, Snow accumulation controls the interannual variation of the mass balance, while surface ablation dominates over frontal ablation.

Considering climate change and the regional context, this is likely the beginning of a retreat phase typical of calving glaciers. Nevertheless, the GPM is still grounded at the Magellan Peninsula; thus, it cannot be ruled out that it will advance again. To better understand what will happen in the coming years, it is vital to continue monitoring the glacier.

794

Micro-topography matters for mosses: centimetre-scale climates as drivers of change

Doctor Krystal Randall^1,2, Doctor Melinda Waterman^1,2, Doctor Michael Ashcroft², Professor Paulo Camara³, Professor Gustavo Zuniga⁴, Distinguished Professor Sharon Robinson^1,2

¹Securing, Antarctica's Environmental Future, University of Wollongong, Wollongong, Australia. ²School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ³Departamento de Botânica, Universidade de Brasilia, Asa Norte, Brazil. ⁴Laboratorio de Fisiología y Biotecnología Vegetal, Universidad de Santiago de Chile, Santiago, Chile

Abstract

Mosses are the dominant terrestrial plant life in ice-free areas of Antarctica. Much like miniature forests, Antarctic mosses support a rich diversity of invertebrates and microorganisms that make up Antarctica’s most biodiverse terrestrial ecosystems. Their growth and productivity are constrained by physiological thresholds of temperature, water, and solar radiation, which vary at different spatial scales. Antarctic moss turfs display highly variable micro-topography over centimetre scales. Changes in moss health over recent decades also appear to be occurring at these same scales. However, the underlying environmental drivers of these moss health changes are poorly understood, making it difficult to predict how these ecosystems will respond to future change and inform conservation efforts.

Antarctic mosses show little adaptation of photosynthetic physiology to the cold Antarctic climate, with photosynthetic temperature optimums closely resembling adaptation to a much warmer climate. Being short-statured and typically forming communities of densely packed shoots, Antarctic mosses are well adapted to maximise heat accumulation and reduce heat losses when sunlight is available, contributing to their survival and productivity on the frozen continent. Their ability to generate leaf-level climates that differ from ambient conditions presents a challenge for remote biological monitoring, as meteorological data do not represent the climate that mosses and their co-inhabitants experience.

We compare the spatial structure of moss microclimates over landscape (10-100’s of metres) and micro-topographic (1-10’s of centimetres) scales, to determine the relative influence of topography and micro-topography on leaf-level climates and moss physiology. We demonstrate that temperature ranges over centimetres can vary as much as normally expected across kilometres of mountainous elevation elsewhere on the globe; showing that centimetre-scale micro-topography has a disproportionately large impact on leaf-level climate and subsequent ecology. Additionally, we present a model of leaf-level climates for use in remote biological monitoring of terrestrial communities and conservation decision making.

796

Creative Antarctica: Australian Artists and Writers in the Far South

Dr Adele Jackson^1,2, Prof Elizabeth Leane¹, Dr Carolyn Philpott¹, Dr Hanne Nielsen¹, Dr Miranda Nieboer², Prof Philip Samartzis³, Dr Sean Williams⁴, Dr Martin Walch¹, Mr William Fox⁵

¹University of Tasmania, Hobart, Australia. ²University of Canterbury, Christchurch, New Zealand. ³RMIT, Melbourne, Australia. ⁴Flinders University, Adelaide, Australia. ⁵Centre for Art + Environment, Nevada Museum of Art, Reno, USA

Abstract

Works of art and literature can question our presumptions, engage our emotions, and inspire us to think innovatively about our relationship with the Antarctic region. Australia, a nation with close historical, geographical, and political connections to Antarctica, has a comparatively long record of supporting creative arts practitioners to experience the continent. However, to date there has been no large-scale critical or curatorial response to this history and no in-depth analysis of the best models for future efforts.

The Australian Research Council funded project “Creative Antarctica” aims to use a combination of cultural analysis, curatorial response and qualitative interview-based research to produce the first comprehensive history and analysis of Australians’ creative responses to Antarctica across all forms of art. Here, we report on the project’s first stage, in which we have constructed a database of over a hundred Australian creative artists and writers who have visited Antarctica for professional purposes, on over 150 separate residencies. From this, we have conducted questionnaires and semi-structured interviews with fifty of these artists and writers to determine what factors contribute to a successful Antarctic residency.

In this presentation, we will report on what we have learned from these interviews, including interviewees’ emphasis on the amount of ice-time and more post-residency support and publicity. We anticipate that our findings will have implications for the way in which future Antarctic arts residencies are selected, structured and promoted. 

797

Research Study for the Design of an Analog Space Mission on Operational Safety and Adaptability to Extreme Environments in Antarctica.

César Gómez CESAR GOMEZ

Fuerza Aerea Colombiana, Bogotá, Colombia

Abstract

The objective of the project is to design an operational safety methodology for space analog missions in Antarctica, and physiological adaptability to the extreme environment. We sought to understand the challenges and risks associated with analog space missions in Antarctica, as well as to design safety protocols and adaptability strategies. Lack of direct experience in analog environments limited understanding of crucial factors influencing safety and performance in hostile situations.

This project addressed this gap by comprehensively analyzing Analog Space Missions such as the Colombian Aerospace Force's THOR and ATLAS missions, examining operational risks, and designing safety protocols and adaptability strategies.

The methodology comprised a series of specific objectives, including analyzing the context and its risks, designing safety protocols, developing adaptability strategies, and continuously evaluating the effectiveness of protocols and strategies through simulations. Several activities were carried out involving testing of biomedical equipment, communication devices, measurement of physiological variables, implementation of adaptability strategies to evaluate and improve the designed protocols and strategies, based on the analysis of analogous space missions and their protocols.

The results of this research are essential to optimize operational safety as part of space mission training in analog environments, improve human adaptability, establish logistical and operational profiles, expand knowledge in extreme environments, contribute significantly to understanding the challenges in analog space environments, and lay the foundation for the future. The interdisciplinary nature of this project, involving fields such as engineering, telecommunications, robotics and health sciences including sports science and aerospace medicine, ensures a comprehensive and effective approach to address the challenges associated with space exploration in extreme environments.

Colombian Airforce Video

798

Collaboration, Ambition, Diversity and Community – core values of the Securing Antarctica’s Environmental Future program

Dr Diana King^1,2, Distinguished Professor Sharon Robinson^1,2, Jodie Weller³, Dr Ilva Sporne⁴, Professor Kerrie Wilson⁴, Hannah Jay⁵, Dr Justine Shaw⁴, Professor Michael Bode⁴, Professor Steven Chown³

¹Securing Antarctica’s Environmental Future (SAEF), University of Wollongong, Wollongong, Australia. ²Environmental Futures Research Centre, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ³Securing Antarctica's Environmental Future, Monash University, Melbourne, Australia. ⁴Securing Antarctica's Environmental Future (SAEF), Queensland University of Technology, Brisbane, Australia. ⁵Independent Consultant, Melbourne, Australia

Abstract

Securing Antarctica’s Environmental Future (SAEF) is an Australian Research Council Special Research Initiative in Excellence in Antarctic Science (ARC SRIEAS) that brings together 158 members across 25 organisations, both national and international, to deliver its interdisciplinary Antarctic research program.

SAEF has a fundamental commitment to equity, diversity and inclusion.

In response to the various EDI issues faced by our members, SAEF has developed a suite of policies and procedures to implement best practice solutions. From gender equity, to implementing specific EDI funding rounds for SAEF workshops, to leadership mentoring, as well as additional field training and field safety procedures, SAEF is working proactively to address the EDI issues faced by those working in the Antarctic research space.

We are proud to showcase our actions and look forward to learning from others across SCAR to implement best practice.

799

Teleconnections between ENSO, SAM and PSA in precipitation anomalies in Southeastern South America

Dr. Pedro Valente^1,2,3, Dr. Francisco Eliseu Aquino^1,2,3, MSc. Andressa Marcher^1,2, Dr Venisse Schossler^1,2, Dr. Jefferson Simões^1,2

¹Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Universidade Federal do Rio Grande do Sul / INCT da Criosfera, Geography, Porto Alegre, Brazil. ³Graduate Program in Geography, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Abstract

Climate variability modes tend to influence and alter precipitation patterns around the world. The present work observed the temporal and spatial influence of the Pacific – South America (PSA), Southern Annular Mode (SAM) and El Niño – Southern Oscillation (ENSO) on precipitation anomalies that occurred in Southeastern South America (SESA) from 1951 to 2020. We used CRU precipitation reanalysis data (version 4.05), with 0.5°x0.5° resolution and ERA5 for geopotential height, zonal and meridional wind. Firstly, SESA was divided with cluster analysis in three sectors: Argentinean, Uruguayan and Brazilian. SESA temporal analyses were generated by finding structural breaks with Alexanderson’s Standard Normal Homogeneity Test. Then, to investigate changes in anomalies intensity and frequency, wavelet transform was applied. It was found structural breaks in Argentinean sector between 1965 and 1984. Also, Brazilian sector revealed a structural break during 1982 El Niño episode. Then, it was noticed that PSA and SAM patterns modified its behaviors between 1984/85, when PSA (SAM) index intensified its negative (positive) tendency. After this change (1982-1985), SESA precipitation anomalies started to exhibit higher values when compared to the beginning of the observed period, reaching almost 3 standard deviations above average. Wavelet also revealed an increment of both frequency and intensity in anomalies after 1985 in Argentinean and Brazilian sectors. The inversion in PSA/SAM index has contributed to PSA behave inversely proportional to precipitation anomalies in the three SESA sectors, increasing positive anomalies in up to 60 mm. Uruguayan region precipitation anomalies oscilled when related with PSA index. Since 1986, southernmost Brazil demonstrated negative relation between PSA and positive precipitation anomalies. The inflection point in the time series indicates that the intensification of PSA's role in precipitation variability in the study area is influenced by SAM and ENSO.

800

Shackleton and Scott: Cultural Heritage Sites in Antarctic Polar Cruise Tourism

Dr Elizabeth Nyman, Dr Jenna Lamphere

Texas A&M University, Galveston, USA

Abstract

In this paper, we examine the role in polar history and maritime heritage sites in modern day polar cruising. From G Adventures’ “Spirit of Shackleton” cruise to Swoop’s “Ross Sea Discovery: In Scott & Shackleton's Footsteps,” the opportunity to visit prominent locations visited by Antarctic polar explorers of the past is marketed on modern cruise voyages to Antarctica and the southern islands. We analyze the texts and/or images in the marketing of these cruise opportunities in Antarctica, why these stories still drive people, and the impact of this kind of tourism on the fragile maritime cultural heritage across the Falklands/Malvinas, South Georgia Islands, and the Antarctic. This paper thus covers how the modern cruise industry allows for a connection to history by its passengers while still protecting the material culture left behind for those and future visitors to see.

801

Cryospheric Cap Degradation as a Mechanism for Antarctic Seep Emergence

Dr Sarah Seabrook^1,2, Prof Cliff Law^1,3, Dr Andrew Thurber⁴, Dr Yoann Ladroit^5,6, Dr Vonda Cummings¹, Dr Leigh Tait¹

¹NIWA, Wellington, New Zealand. ²Victoria University of Wellington, Wellington, New Zealand. ³University of Otago, Wellington, New Zealand. ⁴Oregon State University, Oregon, USA. ⁵Kongsberg Discovery, Horten, Norway. ⁶University of Tasmania, Hobart, Australia

Abstract

The climate sensitivity and significance of subsurface fluid and greenhouse gas reservoirs have received attention in the Arctic and paleoscience. Yet, the presence of these features in Antarctica and their contribution to global methane and the carbon cycle remains enigmatic. We report the discovery of extensive and emergent seafloor seeps, some initiated within the last decade, that are releasing climate-reactive fluids and gases in the coastal Ross Sea. Emission of methane in these shallow waters would expedite transfer to the atmosphere, as reported at other shallow global seep systems. While the origin, driving mechanisms, and environmental consequence of these emerging Antarctic seep systems remain uncertain, we postulate that the emergent seepage results from cryospheric cap degradation initiating new fluid flow pathways, liberating subsurface fluids and gases. This mechanism is inherently climate-sensitive, may be widespread around the Antarctic Continent, and have potential for positive feedback processes. We raise the discussion of whether the emergence of these seep sites represents the crossing of a local, or regional, tipping point with potentially profound local and global implications as the climate continues to rapidly warm.

803

Long-term variability of phytoplankton community reveals a tipping point towards high primary production by the nano-sized fraction in Marian Cove, West Antarctic Peninsula

Dra. Andrea Corredor-Acosta¹, Dra. Andrea Piñones^1,2,3,4, Dr. Gonzalo S. Saldías^5,6,7, Dra. Eun-Jin Yang⁸, Dra. Misa Jeon^8,9, Dr. Sung-Ho Kang⁸, Dr. José L. Iriarte^1,10

¹Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile. ²Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ³Centro de Investigación Oceanográfica COPAS-COASTAL, Universidad de Concepción, Concepción, Chile. ⁴Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems - BASE, Valdivia, Chile. ⁵Departamento de Física, Facultad de Ciencias, Universidad del Bío-Bío, Concepción, Chile. ⁶Centro de Investigación Oceanográfica COPAS COASTAL, Universidad de Concepción, Concepción, Chile. ⁷Instituto Milenio en Socio-Ecología Costera (SECOS), Santiago, Chile. ⁸Ocean Division department, KOPRI, Korean Polar Research Institute, Incheon, Korea, Republic of. ⁹Department of Biological Sciences and Bioengineering, Inha University, Incheon, Korea, Republic of. ¹⁰Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile

Abstract

A twenty-four years in situ time series (January 1998 to December 2021) of surface total and size-fractionated (micro- and nano-phytoplankton) Chlorophyll-a (Chl-a) was analyzed in order to evaluate the primary productivity in terms of phytoplankton biomass in the West Antartic Peninsula over the last decades. The results show a tipping point in the Chl-a concentration and phytoplankton size structure characterized by two distinct periods. An increase of the total Chl-a concentration mainly by the nanophytoplankton fraction was observed during the second period (2006-2021), in contrast with a main contribution by the micro-sized fraction in the first period (1998-2005). These variations of the phytoplankton size structure were observed during the austral spring-summer seasons, finding that the increase of the Chl-a by the microphytoplankton were shifted towards the end of summer, whereas, the Chl-a by the nanophytoplankton displayed a steady increase, reaching their maximum values in early summer over the last years. This interannual change seems to respond to a joint dynamic between the intensification of the north-westerly winds, years with high sea ice concentration during the late winter and lower concentration of silicate in the water column during the second period.

804

Destruction of Sand-Wedge Polygons in Antarctica: a method to track the physical footprint of human activities

Dr Andrew Klein, Mr. Brad Jennings

Texas A&M University, College Station, USA

Abstract

Less than 0.5% of Antarctica is ice-free yet these areas are disproportionately impacted by human activities. Recent studies have found that over 80% of all Antarctic Station infrastructure has been constructed within these ice-free areas. Construction and associated activities can negatively impact the permafrost features found in these areas. Sand-wedge polygons are a ubiquitous periglacial feature throughout the ice-free lowlands of McMurdo Sound, Antarctica. This study examines how the destruction of these polygonal pattered ground features visible in aerial photographs and satellite images can be used to map the spatial extent of human impact in Antarctica using examples at McMurdo Station and established field camps in the McMurdo Dry Valleys. Operations at McMurdo Station, which has supported US scientific activities across the Antarctic continent since the late 1950s, have significantly reduced the extent of sand-wedge polygons in the area surrounding the station and have served to document the increasing extent of physical disturbance at the station over its history. Following McMurdo’s establishment in 1956-57 patterned ground has been reduced from at least 2 km² to under 0.5 km² kilometers. Mapping the presence or absence of sand-wedge polygons near stations and other sites impacted by human activities, although imperfect, is one of a small number of approaches that can be used to successfully document changes in the station’s footprint of physical disturbance through time. Efforts to employ machine learning (ML) approaches to automate the mapping of these features are being explored.

806

From the heroic age to the present day: Challenges and Historical-legal analysis of discrimination against women in Antarctic scientific exploration and research

Camila Barrientos Soto

Antarctic Youth Coalition Foundation, Punta Arenas, Chile. APECS CHILE, Punta Arenas, Chile

Abstract

Years ago in the so-called "heroic age of Antarctic exploration" the white continent became the destiny and longing of brave men, who performed unimaginable feats, but what did women do in this historical period?

Women were not called "heroes" much less "explorers", in fact legally they did not have the right to voice, nor suffrage, or even to manage their assets, they lacked freedom and their adventurous spirit was concurred by their destiny.

Currently, biases have decreased notoriously and the signatory countries of the Antarctic Treaty have shown concern for eradicating the historical discrimination that women have suffered, in fact 55 of the 56 states are also party to the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW), equivalent to 98.21%. However, despite the multiple political-legal efforts, in the areas related to science, technology, mathematical engineering (STEM) there are still important gaps between men and women, an important issue to examine, because the science has become the central axis of Antarctic policy.

My presentation aims to analyze the historical-legal evolution of women's rights in the areas related to STEM at a general level and Antarctic science in particular, as well as what are the legal challenges we face, in addition to making visible what would be the most effective ways to address this systematic problem, since it is important to consider that although we are facing a problem of a global nature, in turn, each country has different ways of understanding and addressing discrimination and gender perspective. All this considering that in the context of Antarctic scientific research, other types of biases and discrimination can be evidenced that studies at the general level have not managed to realize.

808

In Extremis – Culturing the Unique Microbial Diversity of Antarctica’s Geothermal Refugia

Dr. Stephen Noell¹, Mr. Caleb Rosen², Dr. Charles Lee¹, Prof. Matthew Stott³, Prof. Slava Epstein⁴, Prof. Ian McDonald¹

¹University of Waikato, Hamilton, New Zealand. ²University of Southern California, Los Angeles, USA. ³University of Canterbury, Christchurch, New Zealand. ⁴Northeastern University, Boston, USA

Abstract

Antarctica is known to be a hotspot for endemic biota. This is especially true of the biota inhabiting the southernmost active volcano in the world: Mt. Erebus, located on Ross Island. DNA sequencing-based analyses of the microbial communities inhabiting geothermally heated soils on Mt. Erebus have revealed that the topsoil is mostly dominated by globally cosmopolitan microbes, with increasingly endemic microorganisms just a few centimetres into the soil. A highly taxonomically novel species of the order Nitrososphaeria dominates the soils of Tramway Ridge, the largest geothermal site on Mt. Erebus. This species appears to be incapable of ammonia oxidation, generally considered a defining feature of this order. Although DNA sequence data provides valuable information about community composition and functional potential, culturing remains the gold standard for exploring novel physiologies and metabolic pathways. As part of the Multidisciplinary Analysis of Geothermal Microbes in Antarctica (MAGMA) project, we aim to culture and characterize some of the unique and potentially endemic microbes of Mt. Erebus, especially this novel Nitrososphaeria species. Towards this goal, we applied a variety of culturing methods to isolate microbes from subsurface soils (2 meters depth) collected via drilling at two sites on Mt. Erebus: Tramway Ridge and Western Crater. Among the culturing methods used, we deployed our high-temperature application of the in situ culturing device, the i-chip. This novel device, termed the hi-chip, can withstand maximum temperatures of 75℃ for months-long incubations, with resulting cultures recovered in a high-throughput manner. Our first field season has resulted in >400 cultures, with the hi-chip resulting in ~65% success rate per well vs. ~25% success rate per well for traditional liquid culturing. Ongoing efforts are characterizing this wealth of potentially novel microbial cultures.

812

Advancing observations in near-shore and terrestrial regions with ANTOS.

Vonda Cummings

National Institute of Water and Atmospheric Research, Wellington, New Zealand

Abstract

The SCAR Expert Group ‘Antarctic Near-shore and Terrestrial Observing System’ (ANTOS; established in 2016) aims to develop a trans-continental, biologically focused comprehensive and coordinated Antarctic-wide observation system to identify and track environmental variability and change. Essential to assessing and interpreting biological change in the Antarctic (and elsewhere) are observations of biologically relevant environmental parameters. The goal is to use this data to understand the complexities of the drivers of variability and change, across different spatial and temporal scales. In ANTOS we have designed long term observation systems for use in the terrestrial and nearshore marine regions around Antarctica and the Subantarctic, including instrumentation arrays for in situ monitoring of environmental variables, a central web database for real-time data and protocols for baseline biodiversity assessments. This presentation will describe the progress we have made towards a circum-Antarctic terrestrial and coastal marine network.

813

Heatwaves and rapid freezing: does micro-topography influence how often Antarctic mosses exceed temperature thresholds?

Doctor Krystal Randall^1,2, Doctor Xiaotian Zheng^1,3, Doctor Juan Sandino Mora^4,5, Distinguished Professor Sharon Robinson^1,2

¹Securing, Antarctica's Environmental Future, University of Wollongong, Wollongong, Australia. ²School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ³School of Mathematics and Applied Statistics, University of Wollongong, Wollongong, Australia. ⁴Securing, Antarctica's Environmental Future, Queensland University of Technology, Wollongong, Australia. ⁵Centre for Robotics, Queensland University of Technology, Brisbane, Australia

Abstract

Mosses are the dominant plant life in Antarctica, enduring extreme climate conditions to survive. Their growth and productivity are typically limited by low temperatures and drought. However, Antarctic mosses are well adapted to maximise heat accumulation and reduce heat losses when sunlight is available, facilitated through their densely packed turf structure. This enables them to warm to 20-30 ºC above ambient air temperatures, thereby facilitating photosynthesis. While this strategy contributes to their survival and productivity, it may become detrimental during heatwave events by causing them to exceed their high temperature thresholds, resulting in cellular damage.

Antarctic mosses change from green to red under physiological stress. After prolonged stress and/or cellular damage they may reach a tipping point where they become moribund, turn grey and are no longer able to photosynthesise. Changes in moss health toward this tipping point are visually apparent over very fine scales and are related to micro-topography. Micro-topography also governs leaf-level climates in moss beds, such that mosses living in different micro-topographic positions experience very different climate extremes. Mosses on micro-topographic ridges may undergo multiple rapid freeze-thaw cycles per day with the potential to cause cellular damage, while at the same time, mosses a few centimetres away in micro-topographic valleys steadily remain at temperatures above 0 ºC.

Using observational data and modelling techniques, we examine the role of micro-topography for mosses exceeding temperature thresholds and reaching physiological tipping points under heatwave and rapid freezing conditions. We show how fine-scale spatial information can be used to predict tipping points in these communities. As moss cover can be extensive in ice-free areas and play a wider role in insulating underlying soils from temperature change, we discuss how these tipping points affect surface albedo and heat exchange, with flow-on effects for underlying soil temperatures and soil microbial communities.

815

Penguins as vectors for contaminant transport in pristine Antarctic environments

Ms. Megan Reaves¹, Dr. Sally Gaw¹, Dr. Tanya O'Neill², Dr. Fiona Petchey², Dr. Michelle LaRue¹, Dr. Claudine Stirling³, Dr. Malcolm Reid³, Mr. David Barr³

¹University of Canterbury, Christchurch, New Zealand. ²University of Waikato, Hamilton, New Zealand. ³University of Otago, Dunedin, New Zealand

Abstract

Antarctica has been viewed as pristine however, contaminants sourced from local- (e.g., research stations, tourism, commercial fishing) and global- (e.g., mining, agricultural practices, industrial processes) scale human activities have been detected throughout Antarctica. Globally sourced pollutants are transported to Antarctica through long-range atmospheric transport (LRAT), ocean circulation, and biological transportation. It is well known that seabirds function as vectors for pollutants, but there is minimal research evaluating the role Antarctic penguins play in the biotransportation of contaminants. This project aims to determine if Adélie penguins act as vectors by transferring contaminants, specifically plastics, ΣDDT (pesticide), polycyclic aromatic hydrocarbons (PAHS), and metals, between oceanic and terrestrial Antarctica. Secondly, we aim to determine if by returning to the same site each breeding season, Adélie penguins form a natural archive for contaminant levels, revealing fluctuations in contaminants since the nest was established. We used ¹⁴C and ²¹⁰Pb dates to determine the age profiles of the penguin nests from Cape Bird and Cape Hallett, and lead isotope ratios (^204-208Pb) were calculated in one nest profile from Cape Bird to determine shifts in lead sources over time. Here we present the chronologies for 18 elements (Al, As, Cd, Ce, Cs, Co, Cr, Cu, Fe, Hg, Mn, Ni, P, Pb, Se, Sr, Zn, and Zr) in Adélie penguin nests. We observed fluctuations in lead concentrations and isotope ratios corresponding to shifts in anthropogenic and natural lead sources.

817

Coastal benthic communities as sentinels of changing Antarctic environments.

Vonda Cummings¹, Leigh Tait², Jack Massuger³, Lily Pryor Rogers², David Bremner⁴, Ollie Twigge¹, Peter Marriott¹

¹National Institute of Water and Atmospheric Research, Wellington, New Zealand. ²National Institute of Water and Atmospheric Research, Christchurch, New Zealand. ³Australian Institute of Marine Science, Cape Cleveland, Australia. ⁴National Institute of Water and Atmospheric Research, Hamilton, New Zealand

Abstract

Coastal ecosystems are shaped by conditions and pressures at the boundary between terrestrial and open ocean systems, and in the Antarctic they experience perhaps the most variable conditions of all Antarctic marine ecosystems. Coastal benthic communities can be excellent sentinels of change, as they respond to warming, freshening and acidification of seawater, and their composition is often highly correlated with sea ice conditions that are a major driver and responder to climate change. We present the results of a depth stratified (10 - 80 m deep) sampling campaign that aimed to characterise benthic communities and habitats at 10 locations in the coastal Ross Sea, using high resolution remotely operated vehicles and advanced analytical techniques. We describe patterns in benthic flora and fauna and their links to sea ice conditions (e.g. length of cover and timing of breakout), including the sensitivity of some benthic species and the general resilience of others. We also highlight the locations we have selected as sentinels for ongoing long term observations. These will be used to detect and interpret benthic community responses to, and better understand the implications of, environmental change in the highest latitude seas on Earth.

829

Response of a seasonal ice free lake-climate interactions reconstructed from organically synthesized proxies

Dr Mahesh Badnal, Mr Avirajsinh Jadav, Dr. Rahul Mohan

National Centre for Polar and Ocean Research, Goa, India

Abstract

The Larsemann Hills is a major ice-free coastal oasis along the continental margin of East Antarctica and is host to over 150 lakes. The sedimentary sequences that have accumulated in these lakes record changes in local ice sheet extent, relative sea level, lake level changes, productivity and climate-related shifts. These changes can be reconstructed using inorganic and organic proxies. In this study, we reconstruct lake level changes over the last 1600 year BP from a 60 cm radiocarbon dated sediment core from Discussion Lake, Broknes Peninsula of Larsemann Hills. We employed multiple proxies (diatom assemblages, transfer function, elemental concentration and isotopic variation of carbon and nitrogen from bulk sedimentary organic matter and pigments) to reconstruct past environmental such as productivity variation, lake level changes, source of organic matter etc. Stauroforma inermis, Psammothidium abundans and Diadesmis perpusila are the most abundant diatom species while the former two exhibits opposite variation. The lake level changes estimated by transfer function exhibit significant variation during late Holocene. Scytonemin shows anti-correlation to lake level where lower (higher) lake level exhibits higher (lower) scytonemin percent. Similarly, increasing (decreasing) lake level enables D. perpusilla (a subaerial specie) to diminish (flourish). Chlorophyll display covariance with diatom abundance indicating productivity patterns. Also, the TC% is consistently above 16% suggesting a high productivity throughout the down-core. The C/N ratio consistently exhibit > 18 indicating significant input of terrestrial organic matter from the catchment suggesting a consistent seasonal ice-free lake during austral summer. The d¹⁵N exhibits values which are closer to the atmospheric values while one episode intense denitrification is noted at 222 yr BP while d¹³C shows enriched values indicating a well-mixed lake with exchange of gases between the atmosphere and the lake. Neoglacial Cooling dynamics are well recorded in this high-resolution short sediment core.

830

Public Engagement with Antarctic Research: Creating a Research Agenda

Dr Katie Marx¹, Professor Elizabeth Leane¹, Dr Karen A. Alexander²

¹University of Tasmania, Hobart, Australia. ²Heriot-Watt University, Orkney, United Kingdom

Abstract

Most humans will never experience the Antarctic directly, but instead form their attitudes towards the region from indirect sources such as media. With Antarctica facing many threats – not least the impact of climate change – governments, national programs and ENGOs are eager to garner public sentiment towards the continent’s protection. What people know and think about Antarctica is complicated and difficult to measure, varying with factors such as gender, education, age and location. Nonetheless, some trends can be tentatively identified. In particular: public knowledge of Antarctica is relatively low, and people who know more about the continent are more likely to care about it. This points to a need for the Antarctic sector to understand and develop its own capacity to deliver public engagement programs in a coordinated and measurable way.

One step in this direction has been the formation of the Public Engagement with Antarctic Research Action Group within the Scientific Committee on Antarctic Research (SCAR). A key initiative of this group was a survey delivered to members of the Antarctic sector that examined the barriers and enablers that members encountered when conducting engagement work within their own regions and organisations.

In this presentation, we report on the results of this survey. We identify several key barriers that are currently constraining the sector’s ability to engage the public, including a lack of resourcing, a lack of collaboration, and a perceived undervaluing of the skillset required to conduct engagement work within Antarctic organisations. Combined, these results reinforce the importance of engagement work and highlight the need for a cohesive global engagement strategy across the Antarctic sector.

831

Going Under Cover: Interdisciplinary, International Collaboration for Accessing Under Ice

Dr BRITNEY Schmidt

Cornell University, Ithaca, USA

Abstract

“Major technological needs may require pooling of resources for greatest effect. Partnerships, sharing of facilities and technologies, and coordination of efforts maximise return on investments and reduce impacts on the environment.” –COMNAP ARC

Over the past ten years, our team has developed under ice vehicles and instrumentation for deep ice environments. These modular systems are designed to minimize footprint while adapting to the highest priority science, which has also enabled co-developing international and interdisciplinary projects. We have been honored to work in programs managed by the United States Antarctic Program (USAP), Antarctica New Zealand (ANZ), the British Antarctic Survey (BAS), and Norwegian Polar Institute (NPI) through support from multiple US, international and private funding sources. The vast majority of this work has been conducted via hot water drilling through international collaboration leveraging BAS-heritage designs.

Many of the highest priority science targets across Antarctic science require access below ice—be it grounded or floating. From measuring melt rates in the warming ocean to uncovering isolated ecosystems in subglacial lakes, these deep horizons require expanded opportunities for getting under the ice, necessitating collaboration. At the same time, access missions can be resource intensive and thus optimizing the trade space between science value, resource utilization, and logistical requirements is crucial and yet complex to achieve across agencies.

I will share some lessons learned from developing technologies for use in collaborative campaigns, and highlights of working across necessarily international and interdisciplinary programs. Since deep access is necessary for a growing number of questions, I will also discuss expanding availability of access drills. With these experiences as the backdrop, I will comment on some barriers to increased international collaboration and how they might be breached, such as aligning proposal cycles, logistical timelines, and removing institutional silos that make navigating international projects overhead intensive.

833

Rethinking Antarctic Sealing elephanting industry (19th Century). Exploring new historical sources

Dr. Melisa A. Salerno¹, Dr. Maria Jimena Cruz¹, Dr. Andrés Zarankin²

¹Multidisciplinary Institute of History and Human Sciences (IMHICIHU-CONICET), Buenos Aires, Argentina. ²Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil

Abstract

During the 19th century, a global industry focused on the exploitation of marine mammals developed in the South Shetlands (Antarctica). The sealing industry involved a global market where the skins of fur seals were sought for the production of fashion goods, while the oil of elephant seals was used for lighting, and the production of machine lubricants, among other things. For over two decades, the "White Landscapes" project, led by Dr. Andrés Zarankin, has been studying the material remains at multiple sealing sites in Livingston Island. Although important information has shed light on several aspects of the sealing industry, research has generally treated sealing and elephant sealing activities and their production processes collectively. This presentation aims to delve deeper into the distinct importance of each activity, recognizing that while both were often conducted by the same ships, information regarding Antarctic elephant sealing production remains scarce. For this, we propose to consider under-explored documents in Antarctic sealing industry studies, more specifically, ship’s outfitting lists, which consisted in lists of various items that vessels were required to carry. They were usually published by merchants of products such as clothing, ship supplies, sails, navigation instruments, among others.

By doing this, we aim to reflect on the potential of this type of document to enhance understanding of the Antarctic elephant seal oil production process in the South Shetland Islands during the 19th century. Specifically, we will discuss how analysis of these documents can provide insights into different phases of oil production, how they differ from fur production, and their archaeological visibility, refining interpretations of sites analyzed by the project.

We will discuss this potential through an analysis of the provisioning list of the ship Golden West, which journeyed to the Shetland Islands in 1873 for the purpose of elephant seal oil production.

834

Polar tropopause modulation by planetary waves based on radiosonde observations

Dr. Rui WANG¹, Prof. Kaiming Huang²

¹Polar Research Institute of China, Shanghai, China. ²Wuhan University, Wuhan, China

Abstract

Using radiosonde observations at high latitudes, we study the features of planetary waves (PWs)propagation from the troposphere to the stratosphereand their direct effect onthe polar tropopause.The observation indicates that thetropopauseis frequently modulated by PWs. The opposite quasi-periodical variation between the tropopauseheight and temperature superimposes on their seasonal trends. Because of deep modulation by the intense PW activity, the amplitudes of tropopause height and temperature oscillations can attain about 2 km and 8 K, respectively.The temperature perturbation of PWs is rather weak in the tropopause region, and shows a phase reversal after penetrating the tropopause region, while the opposite is true for the zonal and meridional wind perturbations. The unique characteristic of the phase reversal in the temperature perturbation causes the modulation of tropopause height and temperature with an opposite oscillation at the PW period.

835

Mediating Antarctica: how tour operators support and influence tourists’ relationship with the far south

Prof Elizabeth Leane, Dr Katie Marx

University of Tasmania, Hobart, Australia

Abstract

Recent years have seen both a growth in the number of tourists visiting Antarctica and a diversification of the activities offered by Antarctic tour operators, prompting an increase in scholarly and public discourse relating to the ethics and impacts of polar travel. Within this context, tour operators are required to facilitate a meaningful experience that will ideally transform guests into Antarctic ambassadors, while at the same time catering to a diverse array of needs in an ecologically sensitive, high-risk environment. In this paper we present the results of a two-year research partnership between the University of Tasmania and Intrepid Travel that was designed to examine how operators’ mediating role can combine with direct experience to forge meaningful connections with Antarctica that benefit tourists, operators and the polar environment. Over the 2022-23 and 2023-24 southern austral seasons, members of our research team travelled with Intrepid Travel on four voyages to the Antarctic Peninsula, engaging in in-situ observation and conducting multiple semi-structured interviews with over 100 guests and staff.

At the time of writing, we are in the middle of our second field season, so our findings are not yet available. In this presentation, we will report on our results. In particular, we anticipate reporting on 1) guests’ perceptions of the ‘ambassador’ concept promoted by IAATO as well as related barriers to ambassadorship that they raised and 2) the balance between guests’ need for mediation and support versus their desire for unmediated experience. We hope to make recommendations about ways in which operators can adjust their mediation strategies in response to these findings.

843

Spatial and temporal variations of snow and vapour isotopic composition across the East Antarctic Plateau

Dr Mathieu Casado¹, Dr Adriana Bailey², Dr Christophe Leroy-Dos Santos¹, Dr Elise Fourre¹, Dr Vincent Favier³, Dr Cécile Agosta¹, Dr Christoph Kittel³, Dr Laurent Arnaud³, Mr Frédéric Prié¹, Dr Pete Akers⁴, Dr Alexandre Cauquoin⁵, Mrs Leoni Janssen⁶, Dr Barbara Stenni⁷, Dr Giuliano Dreossi⁷, Dr Andrea Spolaor⁷, Dr Joel Savarino³, Dr Martin Werner⁸, Dr Amaelle Landais¹

¹LSCE, Paris, France. ²University of Michigan, Ann Arbor, USA. ³IGE, Grenoble, France. ⁴Trinity College, Dublin, Ireland. ⁵University of Tokyo, Tokyo, Japan. ⁶Uni, Paris, France. ⁷Ca'Foscari University, Venise, Italy. ⁸Alfred Wegener Institute, Bremerhaven, Germany

Abstract

Water isotopes are a tracer of hydrological processes and a paleoclimate proxy from ice core records. The isotopic signal is acquired throughout the hydrological cycle, from the evaporation over the ocean, during each precipitation event, and during post-deposition processes, in particular due to isotopic exchanges between the snow and the moisture in the atmosphere. Due these multiple contributions, the isotopic paleothermometer – or the relationship between isotope ratios in ice and local temperature, on which past climatic reconstructions are based – was only empirically calibrated. Yet, different isotope-to-temperature relationships are obtained spatially in surface snow and temporally in precipitation. Here, we monitor the vapour isotopic composition on a traverse across East Antarctica, as well as at two fixed locations, at the coastal site of Dumont D’Urville and the inland station of Concordia. We show that the isotope-to-temperature relationship is inherently different using vapour isotopic composition temporally and spatially across the East Antarctic Plateau due to fundamental differences in the variations of the rainout fraction across time and space. Since the Rayleigh distillation predicts parallel evolution of vapour and precipitation isotopic composition, our results can be directly transferred to the interpretation of the isotopic signal in ice core records.

845

Consensus in the absence of best available science in times of change: Conservation Measure 24-04

Katharina Heinrich

Arctic Centre, University of Lapland, Rovaniemi, Finland

Abstract

The lack of sufficient scientific data, an argument used by states in international fora discussing the protection and preservation of international marine areas, has repeatedly hindered consensus building in the establishment and designation of conservation measures. This argument is linked to the inherent uncertainty of science, especially concerning future predictions in historically under-researched areas that have only recently been subject to increased accessibility, such as the Polar Regions. While concepts such as best available science (BAS) and the precautionary approach aim to address and embrace uncertainty, data paucity often remains a core obstacle to environmental regulation. This also applies to CCAMLR, where, in some instances, it contributed to difficulties of consensus-building, ultimately hindering the establishment of conservation measures. However, in times of exacerbating climate change impacts and increased awareness of the dynamics of marine ecosystems and the cryosphere, an adequate way that reflects temporal and spatial dynamics to respond to changes is needed. For that, effective consensus-building is a pivotal factor. With the development of conservation measure 24-04 on the establishment of special areas for scientific study in newly exposed marine areas following ice-shelf retreat or collapse, the parties to CCAMLR recognized the impacts of climate change and ecosystem dynamics impacting marine habitats and closed a designated area for purely scientific activities.

Against this background, the presentation aims to explore the aspects of CM24-04 and its relevance for consensus-building in the absence of sufficient scientific data to protect vulnerable areas. As such, the process will be brought in line with and examined against other endeavors for consensus-building, the argument of the insufficiency of scientific data, and its interrelation with each other in regard to conservation efforts in the Southern Ocean under CCAMLR.

846

Global endemism of birds increases from north to south

Matthias Dehling, Steven Chown

SAEF, Monash University, Melbourne, Australia

Abstract

Areas of endemism are highly valuable for conservation because they harbour irreplaceable diversity: species, ecological functions, or evolutionary lineages that are found in few other places. Current approaches to identifying global endemism hotspots are, however, typically biased by methodological idiosyncrasies. Entire regions, especially low-richness areas in the southern hemisphere, such as Antarctica, are commonly excluded from global analyses, and commonly used endemism metrics are highly correlated with local species richness which does not reflect irreplaceability, potentially compromising analytical outcomes and reducing their conservation utility. Yet the extent of these biases have not been assessed, leaving in doubt conservation actions seeking to secure irreplaceability. Here we therefore combined the most recent datasets on avian breeding ranges, functional traits, and phylogeny, and an endemism metric that is independent of richness, to study global patterns of irreplaceability. We unveil global patterns that differ substantially from previous assessments, revealing striking differences between the hemispheres. In the northern hemisphere, endemism declines polewards, whereas the pattern is reversed in the southern hemisphere, resulting in an overall global increase of endemism from north to south. This pattern—consistent for all facets of diversity—results from the smaller and less continuous available landmass in the southern hemisphere, resulting in narrower ranges and reduced overlap in the composition of assemblages. The global distribution of endemism is thus substantially misapprehended, drawing conservation attention away from key areas of irreplaceability. The higher prevalence of irreplaceable, range-restricted species in southern hemisphere avian communities also suggests that they are more vulnerable to the climate crisis, as the limitation and discontinuity of available habitat likely impedes range shifts.

848

LGM’s Fingerprint: Unveiling Ice Sheet Retreat and Terrestrial Change in East Antarctica (29 kyr Lake Record)

Dr. Cheryl Noronha-D'Mello¹, Dr. Mahesh Badnal¹, Dr. Rahul Mohan¹, Mr. Godwin Neppo², Dr. Pooja Ghadi²

¹National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences, Vasco da Gama, Goa, India. ²School of Earth, Ocean and Atmospheric Sciences, Goa University, Taleigao, Goa, India

Abstract

The stability of the East Antarctic ice sheet is crucial for global sea levels and terrestrial environments. Despite its resilience, even minor fluctuations in the ice sheet can have profound impacts. The Larsemann Hills offer insights into East Antarctica's glacial history since the Last Glacial Maximum (LGM), revealing diachronous retreat patterns. Critical gaps persist in understanding ice sheet dynamics, especially during key periods like the LGM and subsequent deglaciation, crucial for understanding their terrestrial implications. This study presents findings of a 29 kyr sediment core record of lake LH73, near the continental ice sheet, employing environmental magnetism and sediment geochemistry (XRF) to probe ice sheet extent, lake evolution, and terrestrial weathering history. Our analysis reveals nuanced environmental signals spanning the Last Glacial Period (LGP) to the Holocene delineated into three key facies: (i) Ice Sheet proximal settings to the lake (29 to 11.8 kyr BP) where dominant mechanical weathering prevailed with minor ice sheet advances coinciding with cold climatic events (post-AIM3 warming, LGM, and Antarctic Cold Reversal), evident through increased magnetic concentration, coarse grain size and weathering indices, (ii) Deglaciation: Initiated by the early Holocene optimum, fostered chemical weathering, and biogenic productivity in the lake. However, a remnant ice lobe dammed the lake, raising water level, supported by Mg/Ca ratios consistent with reconstructed lake levels. (iii) Post-Ice Dam Collapse (7 kyr BP) indicated by the sudden decrease in magnetic concentration and grain size, alongside reduced biogenic productivity and a lowered chemical index of alteration. The lake stabilized after 5 kyr BP devoid of ice sheet influence and increased chemical weathering in the catchment, suggested prolonged ice-free conditions. The ice sheet retreat from 11.8 to 7 kyr BP, in line with previous findings, probably led to a significant reduction in ice loading, potentially affecting the relative sea level.

849

Investigating the Stability of the Denman Shackleton Ice Shelf System, East Antarctica

Dr Sarah Thompson¹, Dr Katie Miles², Dr Madelaine Rosevear³, Dr Duanne White⁴

¹University of Tasmania, Hobart, Australia. ²University of Lancaster, Lancaster, United Kingdom. ³University of Melbourne, Melbourne, Australia. ⁴University of Canberra, Canberra, Australia

Abstract

The Denman Glacier in East Antarctica drains a large area of the East Antarctic Ice Sheet, containing enough ice to raise global sea levels by ~1.5 m. The glacier system is currently stabilised by the Shackleton Ice Shelf and the floating tongues of the Scott and Denman Glaciers. During the 2023/24 Antarctic summer season, we used hot water drilling and geophysical techniques to examine key processes which could affect the future stability of the Denman system.

A combination of ground penetrating radar and seismic was used to investigate the structure of larger areas of the floating system, illustrating significant differences in thickness, but also in fracturing and folding of the ice.

A hot water drilled borehole on the Shackleton-Denman margin was logged with video and an optical televiewer, revealing frequent refrozen ice layers/infiltration ice in the firn and high levels of frazil ice throughout the borehole water column. Borehole video logs before and after drilling through to the ocean showed that the water level in the borehole rose 8.1 m (32.6 m to 24.5 m below ice surface).

Repeat CTD profiles through the ocean from the ice base (180 mbsl) to the seafloor (1055 mbsl) revealed a distinctive three-layer ocean structure, where the deepest layer was a ~300m-thick layer of modified Circumpolar Deep Water (mCDW). A ~500m thick layer of Ice Shelf Water (mCDW cooled and freshened through basal melting) occupied the middle of the water column, while the uppermost layer had a different, fresher, origin and was 0.1 degrees above the local freezing temperature, indicating that basal melting is expected. The presence of a thick mCDW layer at depth suggests connectivity between the ocean cavity and the continental shelf via a trough and highlights the potential vulnerability of the Denman-Shackleton region to ocean heat.

850

Sastrugi - The story of Antarctic sea ice retold

Mr Sean Chua^1,2, Dr Diana Chester³, Dr Petra Heil^1,2

¹Australian Antarctic Division, Kingston, Australia. ²Australian Antarctic Program Partnership, Hobart, Australia. ³University of Sydney, Newcastle, Australia

Abstract

There is a vast place on this Earth

Where the icescape meets the frozen sea

There was one place thought left on Earth

Where man thought that air and water were clean.

The Antarctic and the surrounding ocean are a vast icescape elusive to larger mankind, albeit critical to the regional to global climate and ecosystems. Sastrugi, a project that combines the techniques of sonification, field recording, and musique concrète, crafts captivating and immersive soundscapes that narrate the poignant tale of vanishing sea ice in the Southern Ocean. In the face of a record-breaking year for Antarctic sea ice in 2023, this project is timely and a vital testament to the Earth’s ever-changing climate. The work bridges the chasm between scientific knowledge and the everyday audience, granting access to the Antarctic and Southern Ocean, places that remain both integral yet inaccessible for most people. By transforming data and field recordings into auditory experiences, Sastrugi engages individuals and helps them connect with these regions. We explore sonification of a range of sea-ice data as well as different sound recordings to interpret the icy environment and provide a new perspective of the changes and pressures the system is under. This project not only celebrates the natural wonders of the Antarctic and the Southern Ocean but also underscores the urgency of understanding and addressing the global issue of melting ice. Through art and science, we aim to foster a profound connection between the audience and Antarctica.

851

The Indian Summer Monsoon - Southern Ocean teleconnection during glacial-interglacial periods.

Ms Sharmila Sherin, Dr Manish Tiwari, Dr Vikash Kumar

National Centre for Polar & Ocean Research, Vasco da Gama, India

Abstract

Previous studies suggest a dominant northern hemisphere control of the Indian Summer Monsoon (ISM) on a millennial to suborbital timescale. We have generated Sea Surface Temperature (SST) records for the last 70 kyrs from a sediment core in the equatorial Indian Ocean (SK375-GC01) and explored the oceanic and atmospheric teleconnections between the Indian Sector of the Southern Hemisphere (ISSH) and the ISM on millennial and suborbital timescales. These findings were compared with benthic δ13C records from the equatorial Pacific, Atlantic, and Indian Oceans to assess the impact of the Antarctic Intermediate Water (AAIW) on tropical climate dynamics. We have generated Southern Annular Mode (SAM) signals for the last deglacial period and Marine Isotope Stage 3 (MIS3), using transient climate models, and compared them with Asian monsoon signals, revealing characteristic patterns that indicate positive and negative millennial-scale phases within the SAM. These phases align with periods of weakened and strengthened monsoon events and warming (cooling) of the southern midlatitude, respectively, showcasing an atmospheric teleconnection between the southern extra-tropics and the Asian monsoon on millennial timescales, mediated by the southern midlatitude. The study suggests a tangible link between suborbital and millennial climate variability in the southern extra-tropics and the ISM, facilitated by the ocean tunnel maintained by AAIW and an atmospheric bridge connected by the southern mid-latitudes. The results of our study provide further support for these proposed driving mechanisms, indicating an independent influence of the hemispheres in collectively driving the Asian monsoon variability on millennial to suborbital timescales.

Keywords: Indian Summer Monsoon, Southern Annular Mode, Marine Isotope Stage, Antarctic Intermediate Water.

852

Coastal ice core site identified in Dronning Maud Land, Antarctica: Potential for high-resolution climate reconstructions back to LGM

Dr Vikram Goel¹, Dr Carlos Martin², Dr Kenichi Matsuoka³, Dr Bhanu Pratap¹, Dr Geir Moholdt³, Mr Rahul Dey¹, Dr Laluraj C M¹, Dr Meloth Thamban¹

¹National Centre for Polar & Ocean Research, Goa, India. ²British Antarctic Survey, Cambridge, United Kingdom. ³Norwegian Polar Institute, Tromso, Norway

Abstract

The coast of Dronning Maud Land (DML), facing the Southern Ocean's Atlantic sector, is primarily characterized by the Weddle Gyre, allowing for strong connections between the atmosphere, the Southern Ocean and the global ocean circulation. A high-resolution ice core record from coastal DML spanning the Holocene would help reconstruct the climate variability of the region and the Southern Ocean. Ice-rise summits, with negligible horizontal ice advection and substantial surface mass balance, are considered ideal sites for such ice cores. During the 2021–22 Austral summer, we surveyed two similarly sized (~900 km²) ice rises at 16° E, near the eastern edge of the Lazarev Ice Shelf. Kupol Verbljud (VER) is an isle situated at the calving front, and Kamelryggen (KAM) is a promontory landward of VER. Deep-radar survey reveals ice thicknesses of 560 m under VER’s summit and 525 m under KAM’s summit. We find KAM’s summit region better suited for a long ice core than VER, given its gentler bed slope and simpler ice stratigraphy. Surface mass balance obtained using dated reflectors from shallow radar surveys shows consistent spatial patterns over recent decades. We use a simplified 1-D map view age-depth model and consider ice flow as a combination of two extreme cases: diverging divide flow and shear-dominated flank flow. We determine the flow combination that best reproduces the observed englacial radar stratigraphy and use it to estimate the age of ice. Our findings suggest that KAM is a promising location for obtaining a high-resolution LGM ice core record of climate variability in coastal DML. We found an ice coring site over KAM’s summit with expected ~20 kiloyear-old ice 80 m above the bed at 3 years per centimetre resolution.

853

An Integrated Atmosphere-Sea Ice-Ocean-Ecosystem Observing System for the Ross Sea to the Far East Antarctic Region RSfEAR

Dr Petra Heil^1,2, Dr Craig Stevens^3,4, Dr Clare Eayrs⁵, Dr Won Sang Lee⁵, Prof Pierpaolo Falco⁶, Prof Hyoung Chul Shin⁵, Dr Simon Alexander^1,2, Prof Wolfgang Rack⁷

¹Australian Antarctic Division, Kingston, Australia. ²Australian Antarctic Program Partnership, Hobart, Australia. ³National Institute for Water and Atmospheric Research, Wellington, New Zealand. ⁴University of Auckland, Aukland, New Zealand. ⁵Korea Polar Research Institute, Incheon, Korea, Democratic People's Republic of. ⁶Università Politecnica delle Marche, Ancona, Italy. ⁷University of Canterbury, Christchurch, New Zealand

Abstract

Antarctica and the Southern Ocean occupy key roles in driving and moderating the Earth system, however knowledge of cross-disciplinary connections remains incomplete, especially around its coastal margins. The Antarctic and Southern Ocean are also some of the most data sparse regions globally, both with regard to process studies as well as sustained observations. With a number of international initiatives (UN Ocean Decade, Antarctica InSync, 5th International Polar Year) ramping up, our focus is on oceanic, sea-ice, atmospheric and biogeochemical drivers in the joint Ross Sea- far East Antarctic Region (RSfEAR). RSfEAR spans a large longitudinal range (110oE – 150oW) and encompasses numerous potential “tipping point” contributors, including glacial ice sheets or the polar ocean albedo cycle. At a regional scale, glacial ice shelves and polynyas promote sea-ice growth and underpin diverse and rich marine and terrestrial ecosystems, while atmospheric rivers and glacial runoff destabilize the coupled system. We focus on this large region as it also contains geographic sectors often considered separately, both in terms of science and operationally. Against the backdrop of recent dramatic change in the Earth system, which appears amplified in the polar regions, we derived a functional design for a future integrated ocean–sea ice–atmosphere observing system informed by recent case studies. Our focus is on themes of: i) regional setting, ii) gap analysis, iii) feasible observing strategies, iv) future observing system design, and v) needs and implications for stakeholders broadly.

854

Spatial and temporal variability of phytoplankton composition and environmental parameters in the Pacific sector of the Southern Ocean

Dr Wee Cheah¹, Professor Andrew McMinn², Dr Simon Wright², Dr F. Brian Griffiths³

¹Universiti Malaya, Kuala Lumpur, Malaysia. ²University of Tasmania, Hobart, Australia. ³CSIRO, Hobart, Australia

Abstract

This study investigates changes in surface (<10 m) physico-chemical and phytoplankton composition measured along a transect over 10 years in the Pacific sector of the Southern Ocean (40-70°S, 130-160°E). Sea surface temperature and salinity values were high in the Subtropical Zone (STZ) and mostly decreased southward. Salinity was very constant in the Polar Frontal Zone (PFZ) region with seasonal and interannual variability less than 0.1. Nitrate, phosphate and silicic acid concentrations increased southward with the lowest values in the STZ. An increase in nitrate and phosphate was observed in the Sub-Antarctic Zone (SAZ) and reached maximum values in the Southern Zone (SZ). In contrast, silicic acid concentrations were low (< 3 uM) in the SAZ, with values greater than 5 uM only observed in the PFZ. Chlorophyll concentrations were moderate (> 0.1 mg/m3) in the STZ and SZ, but low in the PFZ. Microphytoplankton were abundant in the STZ, low in the SAZ and increased southward reaching a peaked (> 80%) south of the AZ. In contrast, there was an opposite trend in the distribution of nanophytoplankton, which had a maximum abundance in the SAZ. Picophytoplankton were abundant in the STZ but decreased southward. Photochemical quantum efficiency of photosystem II (Fv/Fm) varied across oceanic zones, delineated by the fronts. Similar to the trend of the microphytoplankton, high Fv/Fm values were observed in the STZ and AZ and low in the SAZ and PFZ.

855

Basal Roughness of the Princess Elizabeth Land, East Antarctica: Relationship with Subglacial Geomorphological Features and Ice Flow

Prof. Xueyuan Tang^1,2, Dr. Kun Luo³

¹Key Laboratory of Polar Science, MNR, Polar Research Institute of China, Shanghai, China. ²School of Oceanography, Shanghai Jiao Tong University, Shanghai, China. ³The Institute for Interdisciplinary and Innovate Research, Xi’an University of Architecture and Technology, Xi’an, China

Abstract

Basal roughness is a crucial parameter for quantifying subglacial geomorphological landforms which offers key insights into glacial geomorphic environments and ice sheet dynamics. Princess Elizabeth Land (PEL) in East Antarctica covers approximately 15% of the Antarctic ice sheet. However, to date, understanding the relationship between subglacial landscape and ice flow in the PEL has remained limited. In this study, we used airborne ice radar data from the Chinese National Antarctic Research Expedition (CHINARE) during the first five austral seasons and publicly available AGAP-North data to calculate a two-parameter spectral roughness index of the subglacial topography. We analyzed the relationship between the spatial distribution of basal roughness and the speed and direction of ice velocity, while classifying the regional roughness results into four different combinations. We find that the subglacial environment in the PEL is more intricate than that previously reported. The area near Polar Record Glacier is characterized by locally rough geomorphology but fast ice flow. The beds of PEL in slow ice flow area are characterized by both rough and flat landforms. Low-lying basins situated in the interior are of considerable interest because they may be characterized by preglacial active erosional landscapes.

856

Study on long-term stratified meteorological conditions for astronomy at Dome A

Dr Yi Hu¹, Prof Zhaohui Shang¹, Dr Bin Ma², Prof Michael Ashley³

¹National Astronomical Observatories, CAS, Beijing, China. ²Sun Yat-sen University, Zhongshan, China. ³University of New South Wales, Sydney, Australia

Abstract

We present long-term stratified meteorological data from multiple-layer automated weather stations, KLAWS and KLAWS-2G. Both facilities are automated weather stations with multiple temperature sensors and anemometers from 2 m to 14 m at elevations. The data spans from 2011 to 2023, a total of 60 months. By analyzing the data, we find that a strong temperature inversion (TI, temperature gradient could reach up to 7°C/m at 4 m) exists just above the ground surface for 50% or more of the time at all elevations. The average wind speed at 4 m is around 4.0 m/s, and the wind speed is seldom larger than 10.0 m/s. The strong TI and moderate wind lead to a stable atmosphere and a shallow boundary layer, above which we could obtain superb free-atmospheric (FA) seeing. Comparing monthly median values of temperature, TI, and wind speed in different years, we find the climate at Dome A exhibits annual variation. Finally, by correlating simultaneous data from KLAWS-2G and KL-DIMM, we find that the FA seeing (i.e., < 0.3 arc second) prefers the existence of strong TI. Therefore, the data from KLAWS are essential for understanding atmospheric turbulence and seeing at Dome A.

857

Microbial diversity and dissolved carbohydrates in the euphotic zone of the Indian sector of Southern Ocean during austral summer

Dr. Bhaskar Parli, Dr. Alok Sinha, Mr. Rantim Bhattacharjee, Dr. Sarat Tripathy, Dr. Anilkumar N, Dr. Rahul Mohan

National Centre for Polar and Ocean Research (NCPOR), Vasco da Gama, India

Abstract

During the 10^th Indian Southern Ocean (ISO) Expedition held during the austral summer of 2018, seawater samples for metagenomic diversity were collected from surface, Deep Chlorophyll maxima (DCM) and 200 m at 8 stations- 2 near Kerguelen islands (KW1 & KW2), 2 in Prydz Bay (PB1 & PB2), and 4 along the 57°E meridional in different fronts (Polar Front-PF, Sub-Antarctic Front-SAF, Southern Sub-Tropical Front-SSTF, and Sub-Tropical Front-STF). In addition, a suite of samples for nutrients, dissolved oxygen, chlorophyll a, total organic carbon (TOC), dissolved monosaccharides and carbohydrates (MCHO and DCHO), and bacterial abundance (TBA) were also collected.

A venn plot of the OTU distribution showed that 16.2% was common in all depths while 24% was unique to both surface and DCM. The OTUs unique to the base of the photic depth constitute upto 13.3%. Distinct differences in the dominant microbial phyla were evident. At Class level, alpha-Proteobacteria was dominant in all the stations and all depths, while gamma-Proteobacteria were found only in SAF and KW waters at DCM and 200 m. Cyanobacteria were largely restricted to SAF, SSTF and STF waters but did not have any specific depth preference. At order level, the SAR-11 clade was observed in all stations and all depths; it’s contribution as high as 85% at DCM in PB2 and PF. Rhodobacterales were second most predominant group in polar waters (upto SAF) followed by SAR324 marine clade and Flavobacteriales. Alpha-diversity (Chao-1) indices of the bacterial community at order-level showed greater species richness at DCM (depth-wise) and in SAF, SSTF, and STF stations (spatially). The Principle Component Analyses showed that Rhodobacterales, Flavobacteriales, Enterobacteriales, and SAR-202 clade were closely associated with TOC, MCHO, and DCHO, while distribution of SAR-11 clade and Actinomarinales were influenced by temperature and salinity. Microbial diversity in ISO was influenced by organic carbon composition and hydrography.

859

Features of Extreme Precipitation at Progress Station, Antarctica

Dr. Lejiang Yu

Polar Research Intitute of China, Shanghai, China

Abstract

Observed daily precipitation data were used to investigate the characteristics of precipitation at Antarctic Progress Station and synoptic patterns associated with extreme precipitation events during the period 2003–16. The annual precipitation, annual number of extreme precipitation events, and amount of precipitation during the extreme events have positive trends. The distribution of precipitation at Progress Station is heavily skewed with a long tail of extreme dry days and a high peak of extreme wet days. The synoptic pattern associated with extreme precipitation events is a dipole structure of negative and positive height anomalies to the west and east of Progress Station, respectively, resulting in water vapor advection to the station. For the first time, we apply self-organizing maps (SOMs) to examine thermodynamic and dynamic perspectives of trends in the frequency of occurrence of Antarctic extreme precipitation events. The changes in thermodynamic (noncirculation) processes explain 80% of the trend, followed by the changes in the interaction between thermodynamic and dynamic processes, which account for nearly 25% of the trend. The changes in dynamic processes make a negative (less than 5%) contribution to the trend. The positive trend in totalcolumn water vapor over the Southern Ocean explains the change of thermodynamic term.

860

Long term monitoring of aeolian processes, features and saltation thresholds on sub-Antarctic Marion Island.

Mr Abuyiselwe Athandile Nguna

University of Fort Hare, Cape Town, South Africa

Abstract

¹Abuyiselwe. A. Nguna

¹Department of Geography and Environmental Science, University of Fort Hare, 1 King Williamstown Road, Alice, 5700, South Africa

Abstract

This study investigates aeolian land features, specifically mega ripples and deflation hollows, on sub-Antarctic Marion Island. These conspicuous features for the cold and wet sub-Antarctic region allude to the crucial role of aeolian processes in this region, and understanding their dynamics is crucial. We conducted experiments at two major aeolian study sites on Marion Island: Mesrug, a vegetation-free area with unconsolidated volcanic material, and Santa Rosa, located at the base of a scoria cone. The research involved deploying various instruments to collect data on wind speed and direction, ambient air temperature, rainfall, air pressure, as well as wind-aspirated sediment traps to capture saltating and suspended sediments within the boundary layer. Our findings reveal that both study sites represent deflation features, with sediments leaving the system more than accumulating within it. To assess the rate of sediment transfer, we employed the ¹³⁷caesium technique, a geochemical tracing method known for its high affinity for fine particles, relatively long half-life, ease of measurement, and well-defined temporal fallout pattern. Our findings provide insights into aeolian sediment transport dynamics, complementing existing approaches. By labelling soil particles with ¹³⁷caesium, we determined the extent and sources of soil loss. In conclusion, the study provides valuable insights into aeolian features and soil erosion processes on Marion Island, contributing to the broader understanding of these critical environmental phenomena.

Key word: ¹³⁷Ceasium, fallout, mega ripples, deflation hollows

863

Recent trends in West Antarctic surface melt linked to central Pacific SST and SPCZ

Dr. Pranab Deb¹, Prof. David Bromwich², Dr. Andrew Orr³, Dr. Kyle Clem⁴, Arnab Sen¹

¹IIT Kharagpur, Kharagpur, India. ²Byrd Polar and Climate Research Center, Columbus, USA. ³British Antarctic Survey, Cambridge, United Kingdom. ⁴Victoria University of Wellington, Wellington, New Zealand

Abstract

We report an increasing trend in surface melting over several West Antarctic ice shelves since the late 1990s during austral summer (December-January-February or DJF), using satellite measurements of surface melt and output from MetUM simulations (at a spatial resolution of 12 km). Significant positive trends were detected over Ross and Sulzberger ice shelves, Pine Island and Thwaites glaciers, as well as over a large part of Marie Byrd Land during DJF, 1998-2018. During this period, an increasing trend in geopotential height anomalies over the coastal West Antarctica led to an increasing trend in northerly wind over the coastal ice shelves leading to excessive surface melting. In contrast, these ice shelves experienced a decreasing trend in surface melting during DJF, 1979-1996, primarily driven by a positive trend in the Southern Annular Mode. Our analysis shows that melt indices are closely tied to sea surface temperature and outgoing longwave anomalies over the central Pacific and South Pacific Convergence Zone via Rossby wave teleconnection. Our analysis suggests that the shift in trend across the late 1990s is linked to the shift in Interdecadal Pacific Oscillation in the late 1990s.

864

First RINGS surveys in Antarctica 1: Establishing the primary ring in Dronning Maud Land

Dr. Daniel Steinhage¹, Dr. Steven Franke², Dr. Kenichi Matsuoka³, DML/EL RINGS Project Members⁴

¹Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany. ²Tübingen University, Tübingen, Germany. ³Norwegian Polar Institute, Tromsø, Norway. ⁴See the membership list, ,, Norway

Abstract

The first RINGS surveys in Antarctica were conducted in Dronning Maud Land (DML) and Enderby Land (EL) coastal regions as a joint effort of 10 nations in the 2023-24 field season. These two regions are characterised by relatively dense data in the western DML, sparse data in the eastern DML and the largest single data gap in EL. Here we report on our surveys in the western DML, which were carried out with the Alfred Wegener Institute's Polar6 aircraft based at Troll Research Station and Princess Elisabeth Antarctica. The top priority of this season, which we achieved, is to complete the primary ring - a simplified grounding line - which is located slightly inland from the current grounding line and has a simple geometry that can be followed by aircraft. We also carried out surveys along a landward ring, about 5 km inland from the primary ring. Our initial analysis found a highly variable bed topography that was not previously known, highlighting the need for further RINGS surveys in this region.

DML/EL RINGS project members (alphabetical order of nations): Jason Roberts, Lenneke Jong, Robb Clifton (Australian Antarctic Division), Frank Pattyn (Universite Libre de Bruxelles), Alain Hubert (International Polar Foundation, Belgium), Sun Bo, Cui Xiangbin (Polar Research Institute of China), Olaf Eisen, Graeme Eagles (Alfred Wegener Institute, Germany), Vikram Goel, Yogesh Ray (National Center for Polar and Ocean Research, India), Masahiro Minowa, Shin Sugiyama (Hokkaido University), Takeshi Tamura (National Institute of Polar Research, Japan), Geir Moholdt, Sven Lidstrom, John Guldahl (Norwegian Polar Institute), Chuma Phamoli (South African National Antarctic Programs), Arjen Stroeven (Stockholm University, Sweden), Jamin Greenbaum (Scripps Institution of Oceanography, University of California), Duncan Young, Don Blankenship (University of Texas Institute of Geophysics, USA)

865

Simulations of the Yield Functions of Semi-Leaded Neutron Monitor Latitude Surveys

Dr. Achara Seripienlert¹, Asst. Prof. Dr. Waraporn Nuntiyakul²

¹National Astronomical Research Institute of Thailand (NARIT), Chiang Mai, Thailand. ²Chiang Mai University, Chiang Mai, Thailand

Abstract

Cosmic rays are highly energetic particles from space. When cosmic rays hit the Earth's atmosphere, they produce cascades of subatomic particles. A large portion of these particles are neutrons which can be detected using a neutron monitor either at a fixed location or on a ship. Shipborne neutron monitors have an advantage in that they can measure particles over a wide range of cutoff rigidity by conducting a latitude survey. In Thailand, we assembled the Changvan neutron monitor, a mobile NM64-type monitor consisting of three units of ¹⁰BF₃ gas-filled proportional counters – only two of which are surrounded by lead. We made two expeditions (2018 and 2019 survey years) with the Changvan from Shanghai to Antarctica and back. To achieve the primary objective of this work, which is to determine the energy-dependent effective area (yield function) of Changvan's leaded and unleaded counters through Monte-Carlo simulations for comparison with the latitude survey data, we used various atmospheric profiles in the simulations. This approach allowed us to examine their effect on the differential response function (DRF) and subsequently compare these findings with the DRF derived from actual data in 2019. This comparison was made for both the leaded edge counters and the unleaded middle counter, all of which are located within the same reflector. Additionally, we simulated count rates of the neutron monitor, generated by various types of atmospheric secondary cosmic rays that reach ground level within specific kinetic energy bins for both unleaded and leaded counters.

868

Baited Remote Underwater Video Systems (BRUVS) for Antarctic biodiversity monitoring

dr simon morley¹, Dr Kim Galvez², Dr Damon Stanwell-Smith³, Mr Jason Hayden², Dr Brandi Revels², Prof Jessica Meeuwig⁴

¹British Antarctic Survey, Cambridge, United Kingdom. ²Viking Expeditions, Basel, Switzerland. ³Viking Expeditions, Cambridge, United Kingdom. ⁴University of Western Australia, Perth, Australia

Abstract

Climate change impacts on the ecosystems along the Western Antarctic Peninsula (WAP) need to be monitored to predict targets for conservation and potential tipping points that will drive ecosystem change. The reduced availability and increased cost of running research vessels has driven the search for technological solutions that allow monitoring and reduce its environmental footprint. Baited remote underwater video systems (BRUVS) are one such innovation for monitoring benthic and mid-water life. Deployed from small vessels and non-destructive, BRUVS create novel opportunities for biodiversity surveys. The UK government funded Blue Belt program has supplied BRUVS to most UK overseas territories, including the British Antarctic Territory, as part of their GOWAN (Global Ocean Wildlife Analysis Network) initiative. BRUVS are also a significant component of Viking Expedition’s polar monitoring program. The combined data helps to build a WAP-scale understanding of the drivers of benthic assemblages. We report on the first results from BRUVS deployed within Marguerite Bay (by BAS from Rothera research station at 67°S) and throughout the Peninsula by Viking (62.5^oS-68^oS). The results demonstrate the well documented wasp-waste, top-down control of the food-web, with large predatory fish being replaced by birds and mammals. Clear differences were also found between locations that can be correlated with latitude, differences in habitat and ice cover. We also discuss the deployment of mid-water BRUVS for monitoring the pelagos and how this could become part of the regular monitoring program.

869

Trends in Southern Ocean phytoplankton iron stress, primary production and bloom phenology

Dr Sandy Thomalla^1,2, Dr Thomas Ryan-Keogh¹, Dr Sarah Nicholson¹, Dr Marie Smith^3,4, Prof Alessandro Tagliabue⁵, Prof Pedro Monteiro⁶

¹Southern Ocean Carbon-Climate Observatory (SOCCO), CSIR, Cape Town, South Africa. ²Marine and Antarctic Research Centre for Innovation and Sustainability, University of Cape Town,, Cape Town, South Africa. ³Coastal Systems and Earth Observation Research Group, CSIR, Cape Town, South Africa. ⁴Department of Oceanography, University of Cape Town, Cape Town, South Africa View author publications, Cape Town, South Africa. ⁵Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom. ⁶School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa

Abstract

Climate change is eliciting widespread adjustments to the physical and chemical environment of the oceans, which affects the distribution and seasonal cycle of phytoplankton primary production (NPP). This in turn impacts ecosystem function and the transfer of carbon, energy and nutrients through food webs with complex feedbacks on ocean biogeochemistry and climate. By applying a number of NPP algorithms to 25 years of remote sensing data we show that almost two thirds of the Southern Ocean is typified by significant negative trends in production. Moreover, we provide evidence of a significant multi-decadal increase in phytoplankton iron stress (from in situ BGC-Argo and ship-based platforms) that could potentially be a cause. Concomitant with these declines in NPP are significant shifts in the amplitude, timing, duration and characteristics of variability of phytoplankton seasonal blooms. Investigating relationships between observed trends and prominent climate drivers highlights regional sensitivities and the complexities of multiple interacting aspects of a changing climate. The majority of these trends differ to those currently being predicted by earth system models, suggesting that they may be underestimating ongoing change in the Southern Ocean, a region where the biological carbon pump is considered to be particularly important. Adjustments of this magnitude at the base of the food web can de-synchronise energy transfer to higher trophic levels, threatening ecosystem services and impacting global climate by altering natural CO₂ uptake.

872

Tectonic Evolution of Albany-Fraser – Wilkes Land orogenic belt during the Mesoproterozoic stage of Rodinia growth

Nikita Borovkov¹, Dr. science Nikolay Alexeev², Igor Kamenev³

¹All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean" (FSBI "VNIIOKEANGEOLOGIA"), Saint-Petersburg, Russian Federation. ²Institute of Precambrian Geology and Geochronology of the Russian Academy of Sciences, Saint-Petersburg, Russian Federation. ³Polar Marine Geosurvey Expedition, Saint-Petersburg, Russian Federation

Abstract

The area of Wilkes Land in East Antarctic is the sufficient part of an Mesoproterosoic orogenic belt expanding from Australia (Albany-Fraser) to East Antarctic (Wilkes Land). The orogen is commonly considered as a result of multi-stage convergence of Mawson and Gauler craton from one side and South Australian (including hidden cratons, i. e. microcontenents) craton from another side. That orogenic evolution included both ocean-ocean and ocean-continent subduction phase continuing to final continent-continent collision at ca. 1190 Ma. The Antarctic part of the orogen is well exposed and provide information for a reconstructions of geodynamic evolution and, particularly, enables to discover different phases of the evolution. We collected several samples both from Bunger Hills area (especially from south-east part) and such areas as Obruchev Hills, Jhones Nunatak, Possetion Nunatak, Harrison Cape, Stratkona mauntains. On this samples collection we perfomed geochemical, isotope geochemical (Sm-Nd, Rb-Sr) and geochronological (U-Pb, zircon, SHRIMP) studies including also T, P – pass calculation. As a result, we obtained Albany-Fraser – Wilkes Land orogenic belt continuation towards south-west, to Obruchev Hills, Jhones Nunatak, Possetion Nunatak, Harrison Cape, until the Stratkona mauntains. Study on zircons indicated the common ages for both Australian and Antarctic (including Bunger Hills area, Obruchev Hills, Johnes, Possetion, Harrison escarpments and Stratkona Mountains) counterparts: ca. 2600-2700 Ma, inherited zircon crystallization (orthogneisses protholiths), 1600-1700 Ma, crystallization of orthogneisses, 1200 – 1150 Ma – metamorphism, multistage (both granulitic zircon grains and metamorphi overgrowths), 1140-1150 Ma, orthopyroxene granitoids intrusions. Obtained petrochronology enables to prove the presence of Step I and Step II of Albany-Fraser orogeny within Antarcic counterpart and also to continue the Albany-Fraser – Wilkes Land orogenic belt deep inside East Antarctic platform structure.

875

Improved Modeling of Polar Electron Energy Flux: Using Temporal Convolutional Networks and Integrated Gradients for Model Interpretability

Dr. Simon Bouriat, Prof. Mathieu Barthélémy

IPAG, Grenoble, France

Abstract

Auroras are the witness of geomagnetic activity and a direct consequence of geomagnetic storms. Impacts of these phenomena on satellites and on the ground can be substantial, ranging from spacecraft charging to disturbances in radio and GPS signals, as well as risks to electrical power networks.

Our study introduces the latest results of a temporal convolutional network (TCN) to model and forecast polar electron energy flux, using Defense Meteorological Satellite Program data and solar wind data from OMNIWeb. Both the Mean Squared Error (MSE) and Tail Weighted Loss functions were employed.

The use of TCN, an architecture considered more unconventional, in space weather had not been explored previously and validates the existence of a multitude of options beyond the conventional recurrent networks for time series forecasting. While LSTMs generally outperform RNNs, their effectiveness diminishes as historical sequences used lengthen, leading to increased complexity and reduced performance. While several tests with fully-connected neural networks (FCNNs) showed similar results than with a TCN, the latter provides more opportunities in the analysis of longer temporal spans. It allows analyzing the entire historical dataset for a single prediction. Here, we arbitrarily kept a 30-minute limit in the past to validate a proof of concept, but will increase it in further studies.

Furthermore, we integrated TCNs with an explainability AI (XAI) technique called integrated gradients (IG) to enhance interpretability. This method allows us to precisely identify which solar wind characteristics within long historical sequences influenced outcomes measured by DMSP in LEO and first results are encouraging.

In the end, both our FCNNs and TCNs outperformed the OVATION Prime model, showing around 20% improvement in Mean Absolute Error (MAE) and 60% in Root Mean Square Error (RMSE). Using the tail weighted loss function significantly improved our results on extreme and rare values but degraded them overall.

876

Autumn leaves: coastal organic carbon settling fluxes in the fall equal the intense summer energy pulse, is climate change at play?

Dr Enrique Isla¹, Prof. Humberto González^2,3, Dr. Eduardo Menschel⁴

¹Instituto de Ciencias del Mar-CSIC, Barcelona, Spain. ²Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Punta Arenas, Chile. ³Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ⁴Corporación Regional de Investigación y Desarrollo Cooperativo, Centro de Investigación en Ecosistemas de la Patagonia, CIEP, Valdivia, Chile

Abstract

Autumnal settling particle fluxes were studied in the Antarctic coastal zone. The study revealed that the organic carbon (e.g., energy) flux exported from the euphotic zone towards the seabed equals the magnitude of the summer pulse when typically, >95% of the Antarctic annual flux develops. The pelagic energy flux was accompanied with centric and pennate diatoms (together >98% of the observed total microplankton cell flux) and euphausiid faecal pellets, which together comprised most of the biogenic particles (and biogenic silica) collected in the sediment trap used in the Doumer Island’s South Bay (DISB), Gerlache Strait. Our results strongly suggest that the most important drivers of the unusual seasonal extension observed for the settling particle export were reduction in sea ice extent, increasing glacier melting and an extended productive period. The present study shows that ongoing environmental warming makes the autumnal biogenic settling particle production near shore more intense than the amounts typically observed off shore, implying a larger atmospheric carbon drawdown, energy supply for the local benthos and organic matter export to offshore waters. The observed microalgae community composition in the sediment trap collections demonstrate that the projected shift from diatoms to cryptophytes projected for a warmer western Antarctic Peninsula offshore waters is not taking place in the near-shore DISB yet. This study may provide a baseline for Antarctic coastal biogenic particle flux studies under the ongoing warming environmental conditions and remarks the need for long-term ecological observations, especially in the absence of historical observations. The present study is a succesful example of Antarctic International scientific cooperation.

879

“Passive Acoustic Networks for Monitoring Marine Mammal Occurrence and Anthropogenic Impact in Antarctic and Subantarctic Regions"

Dr Diego Filún^1,2, Dr Ricardo Giesecke^3,2, Dr Ilse van Opzeeland^1,4

¹Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI), Bremerhaven, Germany. ²Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ³Universidad Austral de Chile (UACH), Valdivia, Chile. ⁴Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany

Abstract

Passive acoustic monitoring (PAM) is a crucial tool in the study of marine mammal populations and environmental dynamics in remote and challenging regions such as the Southern Ocean and sub-Antarctic areas. Our study presents preliminary results from the implementation of an underwater acoustic monitoring network deployed throughout the Weddell Sea, Antarctic Peninsula and Southern Patagonia.

The first objective of this study is to investigate the presence, behavior and distribution patterns of marine mammals in these regions, in addition to monitoring key environmental variables. The second objective of this study is to assess the anthropogenic impact on marine mammals in these remote regions. By detecting and quantifying anthropogenic contributions such as marine traffic, seismic exploration, and industrial activities to local soundscapes, we will assess how these impact acoustic habitats and distribution patterns. By deploying autonomous hydrophones at strategic locations, we are collecting extensive data sets that capture acoustic signatures of marine mammals as well as contextual soundscape data.

Analysis of data recorded in Antarctic and sub-Antarctic areas so far revealed significant temporal and spatial variations in marine mammal vocalizations, indicative of seasonal migrations, breeding activities, and foraging behavior. In addition, environmental parameters such as water temperature, salinity, ice cover and oceanographic currents were simultaneously monitored to assess their influence on marine mammal distribution patterns and soundscape characteristics.

The results of this comprehensive PAM study provide valuable information on the ecological dynamics of the ecosystems that connect the Weddell Sea and Antarctic Peninsula to southern Patagonia, a missing link that will help to more holistically inform conservation and management strategies.

881

Mud, boulders and bird vomit: using glacial geology and biology to constrain Antarctic ice sheet models

Professor Mike Bentley¹, Professor Dominic Hodgson², Dr Andrew Hein³, Dr Steven Binnie⁴

¹Durham University, Durham, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³Edinburgh University, Edinburgh, United Kingdom. ⁴University of Cologne, Cologne, Germany

Abstract

Determining the past size of ice sheets matters for a range of reasons including understanding sea level contributions, the forcing mechanisms responsible for ice sheet change, and for correction of the satellite gravimetric data recording contemporary ice sheet mass balance that are affected by glacial isostatic adjustment (GIA).

Here we report a multi-disciplinary study in the Coats Land-DML region of East Antarctica to improve our understanding of ice load history in this key sector. We combine glacial geology, geochronology, GPS and seismometer deployment, and modelling to improve GIA corrections and thus reducing the uncertainties in ice sheet mass balance. We have mapped and sampled the glacial geological record of ice sheet fluctuations on a transect of nunatak sites stretching ~900 km from the Heimefrontfjella (74° 30’S) to the Whichaway nunataks (81° 30’). The glacial geomorphology is a consistent pattern of landforms and glacial deposits, which record a glacial (ice loading) history of the region that we have dated using two independent approaches of cosmogenic Be-10 surface exposure dating and by radiocarbon dating of stomach oil deposits (preserved stratigraphic deposits of proventricular stomach oil from snow petrels, Pagodroma nivea). The independent approaches provide remarkably consistent and complementary approaches to ice history and provides constraints for our ice sheet modelling.

We report an ensemble of continent-wide ice sheet models that are scored against geological data. Exploring the characteristics of the highest-scoring ensemble members highlights some key features of deglacial behaviour including a relatively narrow range of past excess ice volumes at the LGM, Holocene retreat behind present-day grounding lines with commensurate volume minima, and readvance behaviours. The comparison also allows us to identify areas where more geological data would have high constraining power for ice sheet models.

884

Variability of the structure and intensity of gravity currents in the Antractic coastal polynya areas

Mikhail Molchanov, Pavel Golovin, Ivan Chistiakov

State Scientific Center of the Russian Federation the Arctic and Antarctic Research Institute, Saint-Petersburg, Russian Federation

Abstract

An analysis of the results of modeling the development of the density structure of the dynamics of Antarctic shelf waters in the shelf-slope region is carried out in the entire geophysical range of extreme weather conditions for the formation and existence of polynyas in the Antarctic, which contribute to the intensification of the shelf water formation. For this purpose, the small-scale non-hydrostatic model Fluidity-ICOM is used. Estimates of salt flows (buoyancy) were obtained for various types of ice formation - static in polynyas covered with young ice, and intra-water - dynamic (the most effective) in an open water polynyas. Depending on the increase in the intensity of the dense shelf water formation and the increase in the speed of their spread, three flow regimes along the continental slope have been identified: non-wave - or subcritical; vortex and wave - or supercritical (fast). The obtained estimates of the propagation speeds of density currents and the density difference at their boundaries coincide with the data of field measurements. Estimates of the volumetric (Q_v) and specific of shelf water flows on the continental slope near the area of the cape Darnley polynya in the Prydz Bay were obtained, which make it possible to assess the possible contribution of cascading dense shelf waters to the formation of bottom waters under different flow regimes. The accuracy and correctness of the estimates of volumetric and specific flows is ensured by the small-scale discreteness of calculations, using the non-hydrostatic Fluidity-ICOM model and taking into account the events of increasing the intensity of shelf water formation in an open water polynyas. A significant underestimation of Q_v was revealed with increasing spatial step of calculations spatial step in numerical experiments. Increasing spatial step by a factor of 4 leads to an underestimation of Q_v by ~30%.

885

The influence of growth dynamics of sea ice, and the resulting crystal/physical structure, on the mechanical properties of sea ice

Dr. Tokoloho Rampai^1,2, Prof. Doru Lupascu³

¹Department of Chemical Engineering, University of Cape Town, Cape Town, South Africa. ²Marine and Antarctic Research for Innovation and Sustainability, University of Cape Town, Cape Town, South Africa. ³Institute for Material Science, University of Duisburg-Essen, Essen, Germany

Abstract

While the Arctic regions have been the subject of scientific investigations on the material properties of sea ice since the early 20th century, the study of Antarctic Sea ice as a material has received relatively less attention. In the Southern Hemisphere, the knowledge of sea ice properties is mostly related to the surroundings of the Antarctic bases, and therefore temporally connected to the summer period when they attain the largest occupancy with several cruises. A seasonal perspective on Antarctic Sea ice is only available for the western Weddell Sea and the Antarctic Peninsula, due predominantly to the autumn and winter Polarstern cruises in the 80’s and early 90’s.

Sea ice properties vary drastically with location, due to the dependency on oceanic and meteorological conditions. Thus, sea ice sampling and the determination of its physical and mechanical properties needs to be undertaken over the full season and across the largest spatial region that is practically feasible. In addition, there is great difficulty in assessing the individual variables that contribute to the sea ice dynamics in the field, such as crystal structure, relative porosity volume (brine and air), and biological constituents (EPS), owing to the complexity and short-term variability of the Antarctic Sea ice. Therefore, there is a need to perform year-round experiments in the laboratory to simulate Antarctic conditions and manufacture artificial sea ice. This will allow measurements of the relevant variables in controlled studies and refinement of methodologies that can be used in the field.

886

Mercury over Southern Africa and the Southern Ocean

Dr Lynwill G Martin¹, Prof Suzanne Fietz², Mr Victor Mugabe1²

¹SA Weather Service, Cape Town, South Africa. ²University of Stellenbosch, Stellenbosch, South Africa

Abstract

Sources, distribution and speciation of mercury remain to be explored in many areas of the world, especially in the Southern Hemisphere. The aim of the project presented here is to better understand factors driving the distribution of mercury over and in the Southern Ocean. Here we will present atmospheric mercury observations from three recent (2022-2023) research expeditions into the oceans south of South Africa in winter (June/July/August). We will link these observations with atmospheric mercury data from ground-based monitoring sites in southern Africa, other Southern Hemisphere marine observations, as well as concentrations in the surface ocean along the transects. We will discuss future plans and extend our invitation for collaboration.

888

The South African Polar Research Infrastructure (SAPRI) - Enhancing long-term observations of South Africa’s polar region through seamless access to research infrastructure.

Miss Rabia Mathakutha^1,2, Prof Juliet Hermes^1,2, Dr Tamaryn Morris^1,2, Dr Anne Treasure^1,3, Mrs Anche Louw^1,4, Miss Riesna R. Audh^1,2, Mr Abuyiselwe Nguna^1,2, Mr Yinhla Shihlomule^1,2, Mr Errol Julies^1,2

¹South African Polar Research Infrastructure (SAPRI), Cape Town, South Africa. ²South African Environmental Observation Network (SAEON), Cape Town, South Africa. ³Stellenbosch University, Stellenbosch, South Africa. ⁴South African Environmental Observation Network (SAEON), Stellenbosch, South Africa

Abstract

Established in 2021, the South African Polar Research Infrastructure (SAPRI) aims to ensure the coordination of South African marine and polar research and provide seamless access to existing and new research infrastructure required to develop and enhance long-term observations (LTO) of the polar region that South Africa is custodian to. The establishment of SAPRI is motivated by the recognition of several challenges and opportunities in the South African polar science community. Despite strengths such as scientific excellence and international recognition, the community is fragmented and lacks adequate resources for climate and ecosystem science, particularly in terms of technology, skills, and the use of infrastructure. SAPRI aims to address these issues by integrating, coordinating and strengthening South African polar science, thereby enhancing local and international partnerships and scientific impact within the broader context of the Southern Hemisphere polar region.

Hosted by the South African Environmental Observation Network (SAEON), SAPRI forms part of the national network of long-term environmental observation platforms for coordinated resource use. To address the multiplicity of polar disciplines, SAPRI takes a holistic approach by creating a unified yet distributed infrastructure. Under SAPRI, marine and polar research is enabled and supported through four Integrated Facilities (IFs). These IFs bring together different research infrastructures with common objectives and logistical needs. One is dedicated to data management and societal benefits. Three research-related IFs will ensure the sustainability of LTO on land and ocean, seafloor, atmosphere and space, while innovating to bring new opportunities for ice-related research in Africa through the simulation of the Antarctic and sub-Antarctic environment.

Through collaborative efforts and strategic planning, SAPRI aims to ensure the continuation of current initiatives while promoting new ones. SAPRI seeks international collaborations and knowledge exchange to contribute to a holistic earth system science approach for long-term monitoring.

889

Mapping Southern Wildlife: The SCAR DistAnt Repository

Charlie Plasman¹, Assoc. Prof. Ben Raymond², Anton Van de Putte^1,3, Dr. Bree Woods⁴, Benjamin Merkel⁵, Salome Fabri-Ruiz⁶, Dr. Matt Pinkerton⁷

¹Institute of Natural Sciences, Brussels, Belgium. ²Australian Antarctic Division, Hobart, Australia. ³Marine Biology Laboratory, Free University of Brussels, Brussels, Belgium. ⁴Institute for Marine and Antarctic Studies, Hobart, Australia. ⁵Akvaplan Niva, Tromsø, Norway. ⁶French Research Institute for Exploitation of the Sea, Plouzané, France. ⁷National Institute of Water and Atmospheric Research, Auckland, New Zealand

Abstract

Ecological modeling plays a pivotal role in understanding and managing ecosystems, particularly in remote regions such as Antarctica and the Southern Ocean. Modeling outputs have the potential to cross-fertilize new research studies, as prey models can relevantly inform work on predators, but also to bring new insights into conservation planning. However, accessing and utilizing model outputs from those areas has been challenging to date due to data fragmentation and differences in publishing practices.

To address this issue, we present a repository and associated software tools designed to streamline access to a diverse collection of ecological model outputs from Antarctica and the Southern Ocean. These biological/ecological layers (e.g. species distribution models or similar) will be published via cloud-friendly frameworks to enable efficient use in interactive apps and scientific workflows.

Driven by the SCAR EG-ABI group but supported and enabled by the research community, this initiative undertakes the pressing need for accessible and comprehensive ecological data for the region. The repository will continue to expand through time as we actively collate additional layers. Our goals are to help researchers to efficiently access ecological data, foster better collaboration and scientific understanding, and finally, contribute to informed decision-making in Antarctica and the Southern Ocean.

893

Australian Antarctic Space Analog- a new extreme environment medicine research collaboration

Dr John Cherry¹, Dr Gary Strangman², Dr Emmanuel Urquieta Ordonez³, Dr Jeff Ayton¹

¹Australian Antarctic Division, Hobart, Australia. ²Massachusetts General Hospital, Translational Research Institute of Space Health, Charlestown, USA. ³Baylor College of Medicine, Translational Research Institute Space Health, Houston, USA

Abstract

Australia has conducted expeditions to the Antarctic for more than a century. The Australian Antarctic Division (AAD) maintains three Antarctic winter research stations (Casey, Davis and Mawson) and one sub-Antarctic research station on Macquarie Island. During the summer months the research stations have populations between 30 and 100 expeditioners and over the Antarctic winter the populations reduce to 15 to 35 expeditioners who are physically isolated from the outside world for up to nine months. The isolation experienced by our expeditionary teams, coupled with unique Australian generalist skills in rural and remote medicine, has facilitated the development of an advanced medical model to support expeditioners within the Australian Antarctic Program through the Centre for Antarctic, Remote and Maritime Medicine (CARMM) partners.

The Polar Medicine Unit of the Australian Antarctic Division has had an operational and research collaboration with the National Aeronautics and Space Administration (NASA) since 1993 which has facilitated scientific and operational studies examining human risks associated with spaceflight. Our collaborations with international partners have resulted in research studies relevant to human spaceflight in fields of immunology, psychology, remote monitoring, medical diagnostics, behavioural health, photobiology, virology and epidemiology.

The Polar Medicine Unit of the Australian Antarctic Division has recently committed to a new research collaboration with the Baylor College of Medicine, Translational Research Institute for Space Health (TRISH). This partnership will provide opportunities to undertake relevant space health research and innovation utilising the Australian Antarctic Program in collaboration with TRISH informing the safety and well-being of both Antarctic expeditions and those planning for long duration exploratory space missions.

Initial research and medical technology demonstrations will be discussed.

The Australian Antarctic Division is a division of the Australian Government Department of Climate Change, Energy, the Environment and Water (DCCEEW) coordinating the Australian Antarctic Program.

894

The effectiveness of health assessment for selecting participants of Japanese Antarctic Research Expedition (JARE）

MD GIICHIRO OHNO¹, Mr SOICHIRO KANEKO², MD HIROMICHI MACHIDA²

¹Hokkaido Teuri clinic, Haboro-cho, Japan. ²National Institute of Polar Research, Tachikawa, Japan

Abstract

Purpose: Medical screening system of JARE is evaluated if it is preventing severe diseases in Antarctica.

Method: JARE dispatches approximately 80 people including winter-over team to Antarctica every year. Medical tests are basic examination items plus examinations of psychiatry and dentistry, upper GI endoscope etc. For those over 50 years old, head MRI, chest CT etc. are added. Women will undergo uterine and breast cancer screenings and pregnancy test.

The Judgment Committee consists of 10 members including 8 doctors. Health checks begin one year before departure. The　results of examinations are evaluated each candidate individually in meetings 7 times a year, 2-3 hours each and several rotating meetings.

In 202X, the number of candidates were 90. One third were determined suitable at the first medical evaluation. Two thirds had been put on hold and became suitable after additional treatments: seeing a doctor (internal medicine 38, dentistry 24, and ophthalmology, urology, surgery, psychiatry, gynecology, dermatology and otolaryngology), 18 additional tests, 7 starting medication, 4 surgical operations, 2 colon polypectomies, and 12 preparing medicine for whole Antarctic period.

The rating of unsuitability was 3.3%. Over the past five years, 16 cases were unsuitable showing 5 malignancies, 4 cardiovascular diseases, 3 gastrointestinal diseases, 2 cerebrovascular diseases, 1 renal disease and psychiatric disease.

Results: The number of medical consultations during the wintering period is 4.5 times per person per year. In the 65 expeditions to date, dead case was one who suffered an accident. There were 6 medical evacuations: 2 traumas, renal failure, arrhythmia, visual impairment and hyperthyroidism. There were no ischemic heart diseases, cerebrovascular disorders nor gastrointestinal bleedings.

Conclusion: JARE's medical screening system contributes to exclude high-risk candidates and to prepare for those with illnesses to continue receiving necessary treatment in Antarctica. It prevents deadly diseases in Antarctica.

898

Animating Antarctica, Motivating the World—harnessing today’s most powerful creative medium in Antarctic outreach and science communication

Marlo Garnsworthy^1,2, Kevin Pluck³

¹Icebird Studio, Wellfleet, USA. ²Pixel Movers & Makers, Wellfleet, USA. ³Pixel Movers & Makers, Christchurch, New Zealand

Abstract

With a constant barrage of media at our fingertips and many pressing global and local issues ever competing for attention, capturing policymakers/stakeholders, the general public, and young people with easily understood, scientifically accurate, and engaging information is particularly challenging. Retaining the attention of an overwhelmed, media-saturated populace and spurring them into action is even more difficult. But in looking at the success of video-friendly social media platforms, viral videos, and memorable public service announcements, it’s hard to disagree that, in 2024, no medium has as much power and as broad a reach as short-form video. This medium can be experienced easily, immediately, and repeatedly. An engaging video is rapidly disseminated around the world, can be used in multiple situations (such as educational settings), and endures in minds and hearts.

We—an author/illustrator and a software engineer, both of us science communicators— examine how we combine scientific data, art, poetry/writing, animation, and music to create compelling videos and other materials that can be shared on social media, used in educational and outreach settings, and simply enjoyed. We share our creative and technical process for three animations we produced for the documentary film The Lake at the Bottom of the World, other creative polar science communication projects, and our work-in-progress for the SWAIS2C project and beyond. This presentation provides concrete examples of our visual storytelling, data visualization, animation, and videography that we have used successfully to inform and engage broad audiences with Antarctic issues.

900

Unlocking Antarctic Biodiversity with GBIF: A cloud-based taxonomic approach

Charlie Plasman¹, Yi-Ming Gan¹, Anton Van de Putte^1,2, Dr. Johnathan Kool³

¹Institute of Natural Sciences, Brussels, Belgium. ²Marine Biology Laboratory, Free University of Brussels, Brussels, Belgium. ³Australian Antarctic Division, Hobart, Australia

Abstract

Given the rich diversity of species uniquely adapted to the Antarctic ecosystem, effective taxonomic classification and database management are crucial for informed scientific research, conservation strategies and environmental management. Here, we demonstrate how open data hosted on cloud platforms by the Global Biodiversity Information Facility (GBIF) can improve our understanding of this region's biodiversity by automating the identification of Antarctic species.

We introduce an open and reproducible workflow for taxonomic analysis, leveraging interactive computing environments such as JupyterLab and cloud data services like Google BigQuery. This streamlined process allows us to effectively identify species presence in the Antarctic/Southern Ocean region and evaluate representation across well-known databases/checklists. By harnessing at every step the power of unique identifiers for taxa and capitalizing on the accessibility and cost-effectiveness of GBIF cloud data exports, we significantly reduce technical barriers for this type of work.

Our study aims to establish a scalable framework for efficiently integrating occurrence and taxonomic data, offering valuable insights and potentially unveiling new discoveries in Antarctic biodiversity. Through seamless integration into the Register of Antarctic Species, new identified Antarctic taxa contribute to a deeper understanding of the region's ecological richness.

902

A data system for the Southern Ocean

Dr Antonio Novellino¹, Dr Petra ten Hoopen², Dr Anton Van de Putte³, Dr Alyce Hancock⁴, Dr Julia Bach⁴, SOOS Data Management Sub-Committee⁴

¹ETT Solutions, Genoa, Italy. ²British Antarctic Survey, Cambridge, United Kingdom. ³Royal Belgian Institute of Natural Sciences, Brussels, Belgium. ⁴Southern Ocean Observing System (SOOS), Hobart, Australia

Abstract

The Southern Ocean connects the world’s ocean basins and acts as a sensitive indicator of oceans’ health. Researchers and data professionals from more than 50 countries are part of the Southern Ocean Observing System (SOOS), which facilitates the collection and delivery of essential observations on dynamics of Southern Ocean systems. This collaborative community aims to develop an interoperable data ecosystem that serves a multitude of scientific disciplines and, with a minimum of centralised funding, depends on the generosity and cooperation of a broad community.

At the centre of the Southern Ocean data system is SOOSmap - a portal for well curated and standardised datasets of key circumpolar interest, which draws on the infrastructure of EMODnet Physics. It provides not just access to datasets but also a very visible way to identify gaps in observing and data sharing efforts in the Southern Ocean. In this presentation we will offer familiarisation with the portal, tips how to use its features, a guide how to discover data and how to share new data products with SOOSmap.

904

Near surface drainage networks in Antarctic margins revealed by surface-based radar mapping

Dr Duanne White^1,2, Dr Ian Goodwin^3,2

¹University of Canberra, Canberra, Australia. ²Australian Centre for Excellence in Antarctic Science, Canberra, Australia. ³University of New South Wales, Sydney, Australia

Abstract

Ice marginal hydrologic networks are an increasingly important process affecting Antarctic mass balance, either directly, or via interactions with the structure and dynamics of the ice sheet. Surface melt and drainage networks are receiving increasing attention through satellite-based observations. However, these techniques are unable to detect englacial channels, which remain poorly documented in Antarctica.

Using Ground Penetrating Radar, we delineated near surface and englacial drainage structures observed in two different East Antarctic land-terminating ice margins – a snow covered margin at Law Dome, and a blue ice region adjacent to Bunger Hills. In contrast to airborne radar, ground based observations were able to resolve detailed ice structure and hydrology with limited noise, even in complex topography of the ice margin.

In this presentation, we will describe the distribution of two distinct drainage types located in the study area: a widespread array of near-surface channels, and a deeper, focussed drainage network. We will discuss the influence of subglacial topography on the distribution of both sets of these channels, the potential links with subglacial outburst floods previously observed in this region, and implications for evolution of these drainage networks in a warming world.

905

A reality? Field research on “giant underwater curtains” and legal issues potentially raised during early phase of Antarctic mega-engineering projects to slow ice-sheet melting

Professor Akiho SHIBATA¹, Dr. Jeffery McGEE²

¹Kobe University PCRC, Kobe, Japan. ²Law School/IMAS, University of Tasmania, Hobart, Australia

Abstract

The West Antarctic Ice Sheet (WAIS) is among the most-at-risk planetary climate tipping points. Its irreversible collapse would contribute up to 5 meters to global average sea-level rise. There is a growing scientific debate about whether the WAIS could be stabilised through certain mega-engineering projects, such as giant underwater curtains (Nature, 17 January 2024) to stop or slow ice sheet collapse. The Pine Islands, Thwaites, and Totten areas have been identified as potential outlet glacier systems for these proposals, including research and field experiments. As yet there is no settled terminology for these proposals, which have been invariably called “glacial geoengineering”, “radical adaptation” and “ice sheet conservation”. The fact of different terminologies are used for these fantastic ideas on mega-engineering projects testifies to the uncertain and controversial status they occupy in current Antarctic governance debates.

This paper is an initial attempt to identify some of the intricate and complex legal issues potentially raised by these proposals, focusing on their modelling and early field research phases, before an actual project development phase would start. According to the proponents, those early phases would not raise any legal or ethical problems in the Antarctic context because (i) those activities are guaranteed by freedom of scientific research under the Antarctic Treaty System and the Law of the Sea (ii) there are no usual sovereigns or indigenous peoples from whom a permission would be required. This paper examines these claims and whether these proposals would in any event be consistent with the foundational principles of transparency, peer-review and good faith on which the effectiveness of the Antarctic governance depends. This paper will also examine the legal potential of an evolutionary interpretation of the Madrid Protocol which is on its face is premised on the “comprehensive protection of the Antarctic environment and dependent and associated ecosystem”.

907

Overview of the COVID-19 Pandemic Planning and Response in the Australian Antarctic Program and lessons for future human infectious disease risk planning

Dr Catherine Oermann, Dr John Cherry, Dr Clive Strauss, Dr Jeff Ayton

Australian Antarctic Division, Hobart, Australia

Abstract

The COVID-19 Pandemic challenged health services and policy makers, health systems and individual's health and well-being across Nations and did not spare their National Antarctic Programs.

Australian Antarctic Program COVID-19 responses have been comprehensive, aligning where possible with Australian public health and occupational medicine settings. The austere medical environment and limited sophistication of medical support available across Antarctic programs, in the face of a new and rapidly changing infectious disease risk, required novel targeted and layered responses to ensure the health and well-being of participants where prevention and medical treatment options were unknown and limited.

With increased medical knowledge, experience, readily available vaccination, and increasing immunity, the medical response and policy settings have been adapted to the changing risk profiles.

Impact of the introduction of infectious disease, such as COVID-19 and other respiratory illness, in the small isolated confined populations of Australia's Antarctic Program have been highlighted across the Austral summer seasons since pandemic onset.

Lessons are drawn that will inform ongoing medical, operational and science planning for future seasons and the risk and response to emerging, or known, infectious disease.

909

Precise GNSS positioning with low-cost technology: Case studies from Antarctica

Holly Still, Hamish Bowman, Robert Odolinski, Christina Hulbe, David Prior

University of Otago, Dunedin, New Zealand

Abstract

Field observations of glacier flow velocities are often acquired with costly 'survey-grade' GNSS (global navigation satellite systems) positioning devices, priced at thousands of USD. The high cost poses a barrier to the widespread deployment of GNSS networks, especially in remote polar environments where power consumption and logistical challenges further complicate their installation. Low-cost, open-source, mass-market GNSS technology presents a promising alternative, offering comparable precision at a fraction of the cost (a few hundred USD).

This study examines the reliability and positioning performance of two networks of low-cost u-blox GNSS receivers installed at contrasting field sites in the Ross Sea region of Antarctica: Priestley Glacier (November 2022) and the northern McMurdo Ice Shelf (January 2024). We also conduct experiments to compare the precision of low-cost u-blox systems and co-located survey-grade Trimble R10 systems under both stationary (on land) and kinematic (on flowing ice) conditions. Multi-GNSS (GPS, GLONASS, Galileo, BeiDou, and QZSS), dual-frequency observations are processed using the open-source software RTKLIB. At both field sites, the low-cost and survey-grade systems yielded almost identical error magnitudes when observing horizontal and vertical ice motion. The low-cost u-blox system is capable of centimetre-level horizontal precision (RMS error < 2 cm) over medium baseline (20 to 30 km) kinematic-positioning scenarios. Our work emphasises that competitive and reliable low-cost GNSS systems are readily available and we encourage the application of this technology for cost-effective glacier and ice-shelf monitoring.

910

Identification of viral communities in a terrestrial transect across several ice-free regions of Antarctica

Rafael Gonzalez-Serrano^1,2, Sergio Sanchez-Carrillo¹, María del Carmen Fernández-Moyano¹, Ian R. McDonald^3,4, Stephen Craig Cary^3,4, Antonio Alcami¹

¹Centro de Biología Molecular Severo Ochoa - CSIC, Madrid, Spain. ²University of Alicante, San Vicente del Raspeig, Spain. ³International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton, New Zealand. ⁴Te Aka Matuatua—School of Science, University of Waikato, Hamilton, New Zealand

Abstract

Viruses are the most abundant members of microbial communities. They influence microbial mortality and the evolution of the microbes they infect, food web dynamics, biogeochemical cycles, or even greenhouse gas emissions in the case of viruses present in permafrost. Although most studies on viral communities come from marine systems, there is growing evidence of the enormous relevance of viruses in terrestrial ecosystems and of their implications in a changing world.

Viral metagenomic studies indicate that most of the viruses present in soil ecosystems are unknown. This gives us an idea of the enormous diversity of these microorganisms and the lack of knowledge we have about them, especially in Antarctic terrestrial ecosystems, places of special interest for the study of microorganisms due to their particular physicochemical conditions.

Here we present a metagenomic approach to identify the presence of DNA and RNA viruses found in extremely low-biomass Antarctic ecosystems. The main objective of the study was to analyze the viral diversity present in an Antarctic transect spanning different ice-free regions of Antarctica, from the Northern Victoria Land to remote areas of the Central Transantarctic Mountains passing through the McMurdo Dry Valleys.

Using electron microscopy, we identified a great diversity of prokaryotic viruses belonging to the Caudovirales order, including several tailed phages with typical myoviral and siphoviral morphologies, as well as phages with elongated capsids.

Analysis of the sequencing data indicates the presence of a greater number of contigs belonging to ssDNA and dsDNA viruses than to RNA viruses. We will identify many viral representatives that are specific to each region of the transect, and also viruses that may be present in more than one region along the transect, which would suggest connectivity between different ice-free regions, some of which are separated by thousands of kilometers.

913

Impacts of the opening of the Drake Passage on the Cenozoic global change

Prof. Liang Gao¹, Prof. Junling Pei², Dr. Chenguang Zhu¹, Prof. Zhenyu Yang³, Prof. Yue Zhao¹

¹Key Laboratory of Polar Geology and Marine Mineral Resources (China University of Geosciences (Beijing)), Ministry of Education, Beijing, China. ²State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, China. ³College of Resources, Environment and Tourism, Capital Normal University, Beijing, China

Abstract

Significant changes have occurred on Earth throughout the Cenozoic period, including the reorganization of plates, the opening and closing of critical seaways, variations in ocean circulation, and long-term cooling. However, part of the reason for the incomplete understanding of the relationships between these events is the challenge of identifying the critical area that can control the processes on the Earth's surface. Drake Passage is one of the most important gateways, although its role in Cenozoic global change remains disputed. This study investigates Cenozoic oceansphere and atmosphere data and reconstructs the Phoenix plate subduction process and back-arc extension history of the Drake Passage. Then, together with numerical modeling, the relationship between the tectonics of the Drake Passage and the coeval ocean and climate change is explored. When the passage deepens during back-arc extension, the Antarctic circumpolar current gets stronger. Meanwhile, the global ocean circulation weakens on a larger scale above ~3500 m, whereas it strengthens on a smaller scale below this depth. Stronger deep water disrupt the ocean bottom, oxidizing ¹²C-rich organic materials and releasing more ¹²C into the ocean. This reaction causes a decrease in the benthic δ¹³C (¹³C/¹²C). The oxygen in the deep ocean is also reduced by the oxidation of organic materials. The weakened ocean circulation could let more carbon be sequestered in the abyssal ocean. Furthermore, the deepening of the Drake Passage corresponds to stronger continental weathering, which should be induced by higher temperatures and precipitation in the Northern Hemisphere. Therefore, both these two processes can lead to declining atmospheric CO₂ and long-term cooling after ~50 Ma.

This study was supported by the Natural Science Foundation of China (NSFC) (41930218, 42076223, 42322607).

915

Improving Weather Forecasting Models and Environmental Services in Antarctic and Southern Ocean Regions

Victoria Heinrich¹, Associate Professor Daniela Liggett², Professor Kimberley Norris¹

¹University of Tasmania, Hobart, Australia. ²University of Canterbury, Christchurch, New Zealand

Abstract

In the remote and high-risk environments of the Antarctic and Southern Ocean (ASO), weather forecasts, based on numerical weather prediction (NWP) models, are critical for operational planning and inform decision-making to ensure the human and environmental safety and operational efficiency (e.g., for National Antarctic Programs, tourism, fishing, aviation, shipping and emergency services). However, forecasts and NWP models are poorer and less reliable in ASO regions than elsewhere in the world, and little is known about service usability and reliability, or people’s decision-making processes, information use and knowledge requirements. Cross-disciplinary scholarly research that examines such knowledge and information requirements as well as decision-making processes across different sectors and users is scant. Our transdisciplinary research aims at addressing these gaps in knowledge.

We employed a mixed-methods approach, involving an online survey and workshop to elicit expert opinions across diverse stakeholder communities (e.g., academics, researchers, operators, weather, ice and ocean services information users and decision-makers) on priorities for improving NWP coupled modelling and forecasting services to better meet user needs. This presentation will discuss our findings. Our research participants have knowledge and expertise in ASO regions, NWP, weather, ocean, ice and climate forecasting services and their provision, or activities and operations. The survey examines participant’s perceptions, critical spatial and temporal scales, decision-making, challenges, priorities and recommendations for improvements. It is important to improve ice thickness, sea ice and wind information, and address observational data and data deserts, model performance and verification.

This research will be used in developing community consensus around the current state and future directions of coupled modelling, and understanding how environmental forecasting in ASO regions can be improved in line with user, operator and forecaster knowledge requirements. Findings will progress environmental services in ASO regions increasingly affected by climate change, and thereby improve operational efficiency and human and environmental safety.

916

How good science and engagement informs the best ASPA management plans

Dr Barbara Bollard¹, Ms Ceisha Poirot², Dr Neil Gilbert³, Mr Ashray Doshi¹, Ms Rachel Innes², Dr Melinda Waterman¹, Dr Diana King¹, Dr Jane Wasley⁴, Dr Johanna Turnbull¹, Dr Len Gillman⁵, Dr Sharon Robinson¹

¹University of Wollongong, Wollongong, Australia. ²Antarctica New Zealand, Christchurch, New Zealand. ³Constantia Consulting, Christchurch, New Zealand. ⁴Australian Antarctic Division, Hobart, Australia. ⁵Lennard Gillman Consulting, Auckland, New Zealand

Abstract

A review of the management plan for Antarctic Specially Protected Areas (ASPAs) should be initiated at least every five years as outlined in Article 6, 3 of Annex V to the Protocol on Environmental Protection to the Antarctic Treaty. Reviews should consider the best available scientific information about these important locations, to inform the management provisions outlined in the management plan. Here we showcase examples where scientific data is used to inform management provisions to continue to protect the values of these important sites and how collaboration between environmental managers and scientists can ensure these management plans are well informed, relevant, and as useful as possible for those accessing these sites. Our examples include: 1) a long term monitoring program established in ASPA 135 in the Windmill Islands, East Antarctica which shows significant changes in species composition and plant health since 2000; 2) dating and stable isotope studies which reveal drying trends since the 1960s and how these compare with mosses outside of ASPAs; and 3) the use of remotely piloted aerial systems (RPAS) to produce state of the art maps of vegetation and historic values to support better site management by precisely illustrating the values to be protected for Botany Bay (ASPA 154), Canada Glacier (ASPA 131), Cape Bird (ASPA 116), North-east Bailey Peninsula (ASPA 135) and Clark Peninsula (ASPA 136). We will demonstrate how planning and engagement in preparation for these reviews can lead to both excellent science and best practice management review and decision making.

918

Investigating the dynamics and exchanges across the ice-ocean interface in artificial sea ice

Miss Safiyyah Moos^1,2, Dr Francois Fripiat³, Dr Jean-Louis Tison³, Dr Marcello Vichi^4,2, Dr Anne de Wit⁵, Dr Tokoloho Rampai^1,2

¹Department of Chemical Engineering, The University of Cape Town, Cape Town, South Africa. ²Marine and Antarctic Research Centre for Innovation and Sustainability, Cape Town, South Africa. ³Laboratoire de Glaciologie, Université libre de Bruxelles, Brussels, Belgium. ⁴The Department of Oceanography, The University of Cape Town, Cape Town, South Africa. ⁵Nonlinear Physical Chemistry Unit, Université libre de Bruxelles, Brussels, Belgium

Abstract

Understanding the interactions at the ice-water interface and the exchanges taking place across it is of highest relevance to constrain the large variability observed in Antarctic sea ice.

Dynamic in-situ analysis of ice-water exchanges is difficult due to logistics of measurements, difficulty in isolating external variables and performing high-resolution small-scale investigations over time. Additionally, most field-based techniques rely on sampling full ice cores, which only provide postmortem investigation on the final sea ice sample, instead of continuous data of the dynamics during the sea ice growth process. Laboratory-based artificial sea ice experiments are approximations of the realistic system but allows to perform controlled studies on the exchange features. This study presents experiments from a quasi-2D Hele Shaw cell system in a temperature-controlled sub-zero environment to investigate the convective dynamics associated with sea ice desalination. The small-scale nature of the experiments allows for a high spatial resolution and high-frequency monitoring.

Temperature and impedance are measured to investigate the ice and the convective dynamics in the underlying water at varying initial conditions. Experiments are conducted at temperatures between -5°C and -20°C at varying precooling temperatures to evaluate the effect of temperature on the convection during sea ice growth. The temperature of the water before freezing and the latent heat effects resulting from the freezing of water are seen to increase the temperature fluctuations experienced within the water column below the ice. These temperature fluctuations are linked to the convective effects experienced within the underlying water and can be used to quantitatively investigate convection to support a visual investigation into sea ice dynamics within the quasi-2D system. The temperature and impedance measurements are further used to evaluate the bulk salinity and solid fraction of the ice, which provides an indication on the effect of freezing temperature changes on sea ice desalination.

925

Temperature trends in the Pacific sector of the Southern Ocean

Antonino Ian Ferola¹, Yuri Cotroneo¹, Giorgio Budillon¹, Pasquale Castagno², Pierpaolo Falco³, Giannetta Fusco¹, Enrico Zambianchi¹, Giuseppe Aulicino¹

¹University of Naples Parthenope, Naples, Italy. ²University of Messina, Messina, Italy. ³Marche Polytechnic University, Ancona, Italy

Abstract

In this study we use a 29-year time series of summer Expendable Bathythermographs data collected along the New Zealand-Antarctica 'chokepoint' of the Antarctic Circumpolar Current to analyse the temperature variability of the surface and intermediate layers of the Southern Ocean from 1994 to 2023. Results unveils a significant warming in the northern Antarctic Circumpolar Current flank of the Southern Ocean, while areas south of the Polar Front experience no significant temperature trends. Moreover, we investigated the temperature trends within the primary water masses that characterize the Antarctic Circumpolar Current, providing more details of the warming portrait of the Southern Ocean section under study. Results reveal strong warming trends of approximately 0.27°C/decade and 0.13°C/decade respectively for Sub Antarctic Mode Water and Antarctic Intermediate Water over the study period. Even though data points are just a few, it is worth underlining that over the last ten years this trend results strongly rising. Conversely, Antarctic Surface Water and Circumpolar Deep Water show negligible and/or not significant trends. These results highlight the importance of monitoring ocean temperature variations in Antarctica and their consequences on ice dynamics, crucial for understanding and predicting the future of global climate and sea level rise.

928

Sri Lanka - Correlation between Sri Lanka, N. Mozambique and Antarctica in Gondwana

Dr Geoffrey H. Grantham¹, Dr. Sanjeewa Malaviarachchi², Ms Henriette Ueckermann¹, Dr. Bruce Eglington³, Dr. Linda Iaccheri⁴, Dr Prassana Dharmapriya², Dr Jan.D. Kramers¹, Dr Georgy Belyanin¹

¹University of Johannesburg, Johannesburg, South Africa. ²University of Peradeniya, Peradeniya, Sri Lanka. ³University of Saskatchewan, Saskatoon, Canada. ⁴University of the Witwatersrand, Johannesburg, South Africa

Abstract

Sri Lanka (SL) is positioned next to N. Mozambique and Dronning Maud Land, Antarctica (DML), before Gondwana breakup, in a position requiring ~90⁰ clockwise rotation with the Vijayan Complex (VC, SL) being correlated with the Nampula Terrane (NPT, N. Mozambique). The suture between the NPT and Namuno Terrane (NMT) to the N. is correlated with that between the VC and Highland Complexes (HC,SL). No lithological continuity is seen between the VC and Lutz-holm Bukta (LB) in DML.

Lithologies and structures in the VC and NPT show migmatitic tonalitic and granitic gneiss with shallow to intermediate dipping planar fabrics. The VC fabric show top-to-the-east geometry (top-to-the-S in Gondwana). The planar and linear data suggest transpressional deformation.

Field characteristics and geochemical comparisons between the VC and NPT show the granitoid gneisses are similar to the Mocuba and Culicui Suites of the NPT. The structural geometries of the HC and VC, rotated ca. 90⁰ are comparable to those from northern Mozambique from the NMT and NPT.

Comparisons of U-Pb zircon geochronology show the ages of the NPT and VC are similar; as are data from the Monapo Klippen (MK,NPT), Kataragama Klippen (KK,VC), HC, LB and parts of the NMT comparable. Comparisons of Ar-Ar biotite and hornblende ages from the NPT and VC and LB areas are broadly comparable.

Comparison of radiogenic isotope data (Sr, Nd) from the NPT and klippen with data from the VC and Katargama Klippe are mostly similar.

Available lithological, structural, isotopic and geochronological data consequently support correlations between the VC with the NPT of northern Mozambique and its extensions via the Barue Complex, N. Mozambique to the Maud Belt of western DML, Antarctica. Similarly, petrologic metamorphic P-T paths, isotopic and geochronological data from KK and MK support correlation with the HC, LB and broader central DML.

935

Memories in white: New evidence about the indigenous presence in Antarctica

Diego Aguirrezábal¹, Bruno Gentile¹, Gaspar González², Michael González³, Gonzalo Moyano⁴, Pastor Fábrega-Álvarez⁵, Ximena Senatore⁶

¹Universidad de la República, Montevideo, Uruguay. ²Expedición Pangea, Maldonado, Uruguay. ³Instituto Antártico Uruguayo, Montevideo, Uruguay. ⁴Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina. ⁵Instituto de Ciencias del Patrimonio- Consejo Superior de Investigaciones Científicas, Santiago de Compostela, Spain. ⁶Universidad de Alicante, Alicante, Spain

Abstract

Over the last few years, with the “Antarctic Archaeology The Last Horizon” Project -, we have sought to contribute to the construction of new narratives that help analyze the cultural complexity of Antarctic history. By reinterpreting socio-historical aspects based on new archaeological information, we have made significant progress, mainly by consolidating evidence indicating that the first steps of our species on this continent may have marked the beginning of a process of dialogue and the production of a Landscape in material, social, and symbolic terms. The most recent work conducted in 2024 at the Tómbolo 2 site (Fildes Peninsula, South Shetlands Is.) has allowed us to advance this process far beyond what was expected. The material evidence found there strongly suggests indigenous presence in camps linked to the exploitation of seals from the early 19th century and the use of indigenous-specific knowledge and techniques for resource management in that landscape. This is represented not only in the systematic repurposing and recycling of fragments of English glass bottles as tools but also in the use of local lithic resources to make specific instruments for the tasks carried out there. Linked to this new line of analysis, we have been able to record the different stages of manufacturing these instruments, locating the sources of raw materials, the debris generated during the manufacturing process, and cores and tools at different stages of utilization. This evidence presents a set of new challenges related to the construction of a new Antarctic history. The incorporation of indigenous societies, not only associated with the sealer camps but in the management of various elements of the landscape, requires more comprehensive approaches that allow for the analysis of the human occupation process in Antarctica from a multicultural and multi-ethnic perspective.

939

Mass balance of Antarctica from GRACE, CryoSat and ICESat

Prof Rene Forsberg¹, Ms Barbara Jenny¹, Dr Nicolaj Hansen²

¹DTU Space, Lyngby, Denmark. ²Danish Meteorological Institute, Copenhagen, Denmark

Abstract

Understanding the long-term changes of the Antarctic ice sheet has global climate significance, especially on long term global and regional sea level rise predictions. We present results of current satellite-derived ice sheet mass change time series using satellites GRACE, GRACE-FO, CryoSat and IceSat, covering now a 22 year time span. The GRACE time series shows the ongoing acceleration of mass loss, mainly from the West Antarctica and Peninsula regions, with major glaciers in East Antarctica now also starting to lose mass. The mass change results are are confirmed both for the entire ice sheet, as well as on basin scales, by satellite altimetry in combination with firn density and surface mass models derived from new HIRHAM meteorological models, in an integrated inversion. We also confirm recent changes using the GRACE-FO laser ranging instrument, showing the potential og future satellite missions such as GRACE-B and NGGM to continue monitoring of Antarctica mass loss.

941

ROCK GLACIERS IN THE ANDES OF CHILE AND ARGENTINA: A NON-PERMAFROST CASE

MSc. Eneko Beriain^1,2, Ing. Ashley Apey¹, MSc. Felipe Ugalde¹, PhD. Gino Cassasa^1,3, PhD. Kenji Yoshikawa⁴, PhD. Cedomir Marangunic¹

¹Geoestudios, Las Vertientes, Chile. ²GEOnomadic, Pucón, Chile. ³University of Magallanes, Punta Arenas, Chile. ⁴University of Alaska Fairbanks, Fairbanks, USA

Abstract

In this contribution we present evidence of rock glaciers (RGs) in the Andes of Chile and Argentina which shows that they are located outside the permafrost environment and, generally, at lower elevation. Drilling surveys performed on RGs in Chile shows the presence of an ice-rich (>80% in volume) internal core, which supports a glacigenic and thus non-permafrost origin, having evolved from debris-covered glaciers, process currently ongoing.

Using available inputs (global permafrost models of Gruber 2012 -G2012- and Obu et al., 2019 – O2019); ERA-5 meteorological reanalysis data; and national glacier inventories), a statistical analysis is performed to estimate the number of RGs within higher permafrost probability areas.

The sample of RGs includes both inventoried in Chile and Argentina between 30ºS and 37ºS. A selection of RGs larger than 0.5 hectares was made to avoid the possibility of considering relict RGs with insignificant ice content. The total sample is 8011 RGs whereas the selected sample is 251 RGs.

In general, a low correlation is observed when comparing the spatial distribution of permafrost probability with RGs. Considering a probability index >0.75 for each model, according to O2019, permafrost occurs in 41% of the total RG sampled area and 48% of the selected RG area, whereas according to G2012 permafrost occurs in only 4% and 6% of the sampled and selected areas, respectively.

Based on ERA-5 data, the -2˚C and -4˚C mean annual air temperature (MAAT) isotherms were calculated, representing good indicators of permafrost occurrence. For the 1961-1990 period (G2012 model), 44% and 18% of the RGs are below the -2˚C and -4˚C MAAT isotherms, respectively, whereas for 2000-2016 (O2019 model), the numbers diminish to 40% and 15%, respectively.

According to both models analyzed, a large proportion (>50%) of RGs are located outside permafrost areas, supporting therefore a glacigenic origin.

943

Responses of Sanionia uncinata to climate change in Maritime Antarctica: soil moisture as a determinant

Dr Gustavo E. Zúñiga^1,2,3, Dr Melinda J. Waterman^4,5, Dr Marisol Pizarro^1,2, Dr Rodrigo A Contreras¹, Dr Angelica Casanova-Katny⁶, Dr Sharon A. Robinson^4,5

¹Universidad de Santiago de ChileSantiago, Santiago, Chile. ²Centro para el Desarrollo de la Nanociencia y la Nanotecnología, Santiago, Chile. ³Securing Antarctica’s Environmental Future, USACH, Santiago, Chile. ⁴School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia. ⁵Securing Antarctica’s Environmental Future, Univewrsity of Wollongong, Wollongong, Australia. ⁶Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile

Abstract

Antarctic vegetation is changing at an accelerated rate due to climate change affecting the region. As a result of warming and ice melting in the Maritime Antarctic mosses are expanding onto wet soil, while in dry areas there is a reduction in growth. Our group has studied the effect of climate change on Antarctic mosses over the last 6 years. During this period, we have recorded environmental variables, such as air and soil temperature, UV-B radiation levels and biochemical and molecular responses in populations of the moss Sanionia uncinata growing on Ardley Island and near Collins Harbour, King George Island, South Shetlands.

Our results show for the first time that warming and UV-B radiation levels have little effect on the development of S. uncinata, while soil moisture is affecting this moss, which although tolerant to desiccation, is showing a decrease in its cover. In humid places, S. uncinata develops biochemical and molecular strategies that allow it to cope with the increase in temperature and UV-B radiation in recent years. Among the most important biochemical responses, we have documented an increase in the activity of antioxidant enzymes, which maintains the oxidative status of the moss, while at the molecular level there is an accumulation of compounds capable of filtering UV-B radiation.

Together, these results suggest that S. uncinata possesses physiological plasticity to acclimate to a changing climate. However, water availability remains a critical environmental factor that will determine its survival in a scenario of sustained warming.

946

Cooling the coldest continent: The 4 December 2021 Total Solar Eclipse over Antarctica

Dr René Garreaud^1,2, Deniz Bozkurt^3,2

¹Universidad de Chile - Department of Geophysics, Santiago, Chile. ²Center for Climate and Resilience Research, Santiago, Chile. ³Chile

Abstract

Solar eclipses are impressive astronomical events attracting the curiosity of the people from ancient times. On average, a total solar eclipse (TSE) occurs every 18 months somewhere on Earth, but a given location experiences a TSE every 380 years. Given the marked and varied effects of solar eclipses on near-surface and free-tropospheric atmospheric conditions, there is a mounting body of literature describing the meteorological effects of solar eclipses and contrasting them against modeling results. Relatively few studies have been conducted on the Southern Hemisphere (SH), and only one TSE (23 November 2003) has been described over Antarctica.

On December 4th, 2021, the moon blocked the sun over the high latitudes of the SH, with the path of totality arching from the Weddell Sea to the Amundsen Sea, thus producing a ~2-min TSE over the Ronne-Filchner ice shelf and Ellsworth land at the base of the Antarctic peninsula. In this work, we present high-resolution meteorological observations at Union Glacier base, the only settlement under the path of totality. These observations were complemented with meteorological records from 47 of stations across Antarctica, where obscuration varied from 100 to 40%. Notably, the largest cooling (up to 5°C) during the eclipse was found over the East Antarctica dome while many other sectors see no change in temperature. A simple radiative model partially captures this disparate temperature change if the cloud cover is prescribed. To further diagnose the effect of the eclipse on surface meteorology we ran multiple pairs of simulations (eclipse enable and disable) using the Polar WRF model. The overall pattern and magnitude of the simulated cooling agree well with the observations and reveal that, in addition to the solar radiation deficit and cloud cover, low-level winds and the height of the planetary boundary layer are key determinants of temperature changes.

952

Impact of climate change on snowmelt on the Antarctic Peninsula during heatwaves using pseudo-global warming simulations

Dr. Sergi González-Herrero¹, Mr. Michael Matějka², Dr. Kamil Laska², Dr. Michael Lehning¹

¹WSL Institute for the Snow and Avalanche Research (SLF), Davos, Switzerland. ²Masaryk University, Brno, Czech Republic

Abstract

Snow and glacier melt over the Antarctic Peninsula (AP) predominantly occur during brief heatwave events in summer season. These events are expected to increase due to climate change. Existing of surface melt have largely relied on relatively coarse-resolution models, which are not able to discern on small snowfields and ice caps over AP islands. Here we introduce high-resolution simulations using CRYOWRF, a coupled version of the Weather Research and Forecasting Model (WRF) with the snow model SNOWPACK. The objective of this study is to quantify the impact of the climate change influence over the snowpack melting during a heatwave event over James Ross Island in the Antarctic Peninsula and to identify the primary drivers that increases the snowmelt. To analyze the thermodincamic impact of global warming on these events we use the pseudo-global warming approach. In this method, the melting event between 12 and 24 Desember 2022 is simulated with the current initial conditions as a control run and with the initial conditions modified by the “delta” change with the SSP2-4.5 and SSP5-8.5 climate scenarios from a CMIP6 global climate models ensemble. Quantification of the role of global warming is achieved by subtracting the control run from the PGW simulations. The results offer a quantitative insight into the impact of global warming on a heatwave melting events and its impact for the snowpack melt bridging the gap between atmosphere and snow processes at high-resolution.

954

Microplastics and their interaction with zooplankton in an Antarctic Lake: a perspective with environmental concentrations and presence of biofilm

Evelyn Krojmal¹, Juan Pablo Lozoya¹, Franco Teixeira de Mello¹, Barbara De Feo¹, Miguel González-Pleiter², Gissell Lacerot¹

¹Centro Universitario Regional del Este, Maldonado, Uruguay. ²Facultad de Ciencias, Universidad Autonoma de Madrid, Madrid, Spain

Abstract

Plastic pollution in aquatic ecosystems causes enormous concern due to its rapid dispersion and persistence in the environment. The Antarctic system is not exempt from this global issue, with macro and microplastics already detected in various ecosystem matrices. These include sea ice associated with glaciers, organisms like birds, meltwater streams, beaches, marine sediment, and marine-coastal waters. This presence poses a significant threat to the environment and its fragile fauna. However, there is no study in antarctic lakes nor zooplankton experimentation with environmental concentrations of their habitat. Understanding the sources and magnitude of this threat in the Antarctic remains a significant challenge, with the generation of fundamental information identified as a priority. In this study we assessed environmental microplastics (MPs) densities, and the ingestion and survival rates of Antarctic limnic zooplankton experimentally exposed to irregular MPs in different conditions (i.e. concentrations, presence of biofilm). Limnic water samples were taken in 2023 with a Surber net in the entering and leaving of the lake. The shape, color, size, and density of MPs were analyzed with a stereomicroscope, and the polymeric composition with a micro-FTIR. MPs were detected in all samples (densities between 0.18-0.86 items.m3), with fibers always being more abundant than fragments (>80%,) except once in the entering (50%) where only 2 fibers sets were detected. The most common polymers were PES, PET, and acrylic. Branchinecta gaini and Boeckella poppei were the model organisms which were obtained from Uruguayan and Ionospheric Lakes, both located in the Fildes Peninsula (King George Island, 62º11´4´´S; 58º51´7´´W). Our results confirmed MPs ingestion in both organisms, in general with low grazing rates. This study offers fundamental insights that directly contribute to the objectives and challenges of the Antarctic Treaty System.

955

Relevant biological processes in penguin molecular evolution revealed by pleiotropy effect analysis

PhD. Felipe Avello-Duarte^1,2, PhD. Luis Pertierra², PhD. Pablo Razeto-Barry³, PhD. Juliana Vianna^4,2, PhD. Elie Poulin^1,2

¹Facultad de Ciencias, Universidad de Chile, Santiago, Chile. ²Instituto Milenio BASE, Santiago, Chile. ³IFICC, Santiago, Chile. ⁴Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile

Abstract

The Antarctic continent has been consistently characterized as a natural laboratory to study unique evolutionary histories and processes. Within these histories, penguin evolution is a fascinating example of diversification and adaptation in Antarctic and sub-Antarctic ecosystems exhibiting a unique way of living among extant birds. The genomic changes involved in their evolution are of special interest to better understand the way genes contribute to those adaptations by means of their participation in relevant biological processes. Evolutionary modeling suggests that meaningful information about a biological process can be obtained by the examination of the relation between the pleiotropy and molecular evolutionary rate of the genes involved in the process. Significant correlation between both variables can reveal the historic changes in the fitness landscape of the species, which can be used to detect meaningful biological processes that can be obscured or dismissed by classic selection signal studies. This approach makes use of the bias that pleiotropy incorporates into the molecular evolutionary rate variation among coding sequences to reveal hidden selected biological processes. Here we implement a genome-wide analysis of 18 penguin species, measuring the pleiotropy and molecular evolutionary rate of all detected coding sequences, which gives us a descriptive insight into the distribution of these variables across penguin genes. Using this methodology multiple biological processes meaningful for the evolution of different penguin genera were found. Injury healing and equilibrium was found for Eudyptes, starvation response and glucose metabolism in Aptenodytes, circulatory and neural development for Pygoscelis, and learning and glycosylation processes in Spheniscus, among others. Additionally, we use environmental data from their marine and terrestrial distributions to correlate changes in functionality with ecological variation. This investigation offers not only novel applications of theoretically born genomic tools, but also new insights into penguin history and adaptation.

961

Space climate in the ionosphere over the Antarctic Peninsula as deduced from the ionospheric sounding at the Akademik Vernadsky station

Dr Andriy Zalizovski^1,2,3, Mgr Volodymyr Lisachenko², Dr Oleksandr Koloskov^1,2,4, Prof Yuri Yampolski², Dr Sergiy Kashcheyev², Mgr Bogdan Gavrylyuk^1,2, Dr Andriy Sopin^1,2, Mgr Oleg Budanov², Dr Anton Kashcheyev⁴, Dr Oleksandr Bogomaz^1,5

¹National Antarctic Scientific Center of Ukraine, Kyiv, Ukraine. ²Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine. ³Space Research Centre of the Polish Academy of Sciences, Warsaw, Poland. ⁴University of New Brunswick, Fredericton NB, Canada. ⁵Institute of Ionosphere, Kharkiv, Ukraine

Abstract

Akademik Vernadsky Ukrainian Antarctic station (hereinafter Vernadsky) is located at the Antarctic Peninsula area (geographic coordinates: 65.15 S, 64.16 W) in proximity to the center of the Weddell Sea ionospheric anomaly. This is also why a behavior of the ionosphere over the Vernadsky represents a significant point of interest. Vertical ionospheric sounding is conducted there almost continuously since the late 1950-s when the British Base F operates here. The IPS-42 ionosonde manufactured in Australia has been operating since 1983, when the station had a name Faraday. The station was transferred from Great Britain to Ukraine and renamed to Vernadsky in 1996. Since 2017, a portable Doppler ionosonde developed and manufactured collaboratively by the Abdus Salam Centre for Theoretical Physics (ICTP, Italy), University of New Brunswick (UNB, Canada) and Institute of Radio Astronomy of the National Academy of Sciences of Ukraine (IRA NASU) is operating at the Vernadsky in conjunction with IPS-42. In 2022, a passive position with a new antenna system was installed 400 m from the active one, enabling the distinction of O- and X- polarization modes in the signals reflected from the ionosphere. Furthermore, the passive position of the ionosonde was successfully tested on board the research vessel Noosfera during her navigation in the Drake Passage and along the Antarctic Peninsula in 2022 and 2024, and from Antarctic Peninsula to Cape Town in 2023. Ionospheric observations at Vernadsky enable the analysis of long-term, climatic changes in the ionosphere over the Antarctic Peninsula. Our current study focuses on analyzing climate changes in ionospheric parameters and their responses to solar and geomagnetic activity. We will report the details of long-term changes in the ionosphere based on the data of vertical sounding at the Vernadsky across different seasons for almost three solar cycles.

963

Exploring the Linkages between Antarctic Sea Ice and Indian Summer Monsoon

Dr Sheeba Chenoli^1,2, Dr. Siti Syairah Atiqah Azhar², Prof Azizan Abu Samah¹

¹Dept of Geography, Universiti Malaya, Kuala Lumpur, Malaysia. ²National Antarctic Research Center, Kuala Lumpur, Malaysia

Abstract

We investigate the connection between Antarctic sea ice extent variability within the Indian Ocean sector and Indian summer monsoon rainfall. Specifically, we examine the relationship influenced by the Mascarene High. Our analysis covers the period from 1979 to 2013, employing a combination of reanalysis, satellite, and in-situ observation data. Through empirical orthogonal function (EOF) and correlation analyses, we find significant correlations between the sea ice extent (SIE) during April-May-June (AMJ) and summer monsoon rainfall over the Peninsular India region during June-July-August-September. Notably, the first and third modes of principal component (PC1 and PC3) of SIE in the Indian Ocean sector during AMJ exhibit notable associations with the second mode of principal component (PC2) of Indian summer monsoon rainfall. Analysis of reanalysis data highlights that variations in SIE in the Indian Ocean sector trigger meridional wave train responses across the Indian Ocean for both principal component modes. Positive (negative) anomalies in SIE, as depicted by first and third EOFs (EOF1 and EOF3), correspond to the strengthening (weakening) of the Polar, Ferrel, and Hadley cells, thereby influencing convective activity over Indian latitudes. Consequently, weaker (stronger) convective activity during low (high) sea ice phase years results in reduced (increased) rainfall over the region. Additionally, we observe a weaker (stronger) polar jet during low (high) sea ice phases.

964

Plastic debris on the shores of Hope Bay: stranded testimony of the historical occupation in the northern Antarctic Peninsula

JuanPablo Lozoya¹, Miguel González-Pleiter^2,3, Gissell Lacerot¹, Bárbara De Feo¹, Evelyn Krojmal¹, Carlos Edo⁴, Francisca Fernández Piñas^2,3, Roberto Rosal⁴, Franco Teixeira de Mello¹

¹Centro Universitario Regional del Este (CURE), Universidad de la República, Maldonado, Uruguay. ²Department of Biology, Faculty of Science, Universidad Autónoma de Madrid, Madrid, Spain. ³Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain. ⁴Department of Chemical Engineering, University of Alcalá, Madrid, Spain

Abstract

Plastic pollution is a clear environmental threat in the Antarctic Treaty Area (ATA), generating growing scientific and management concerns. However, available information on the distribution and composition of plastic debris in the ATA remains limited and incomplete and mostly based on opportunistic sampling over time and space. Although permanent human presence in Antarctica dates to the end of World War II, its exponential increase in recent decades could be one of the main causes of plastic pollution in such a remote area. This would be related to scientific, logistic and tourism activities as the main local sources of plastic waste, but also to the historical evolution of waste disposal and management in Antarctica. In 2023, we assessed the density, morphology, polymeric composition (ATR-FTIR), and spatial distribution of plastic debris on the coast of Hope Bay (north Antarctic Peninsula). Based on transect surveys along the coast (10 m width/person), sampling points (5 m radius surface) were defined by the naked eye detection of at least one plastic debris. Plastics were quantified, measured, weighted, and classified based on CCAMLR marine debris categories. About 3,800 items were collected in more than 90 sampling points, with densities increasing near current and historic infrastructures and decreasing towards remote and more pristine areas. The most striking presence was historical plastic debris, such as old sledge dog food containers, eyeglasses, toothbrushes, and electrical devices. These results are a clear testimony of the implications of plastic pollution over time, including the micro and nanoplastics they may generate.

967

Ocean circulation and bathymetry controls on the presence of a biological hotspot at the northern Antarctic Peninsula

Dr Andrea Pinones^1,2,3,4, Paula Amador-Veliz¹, Albert Palomino^1,2,4, Dr. Lucas Kruger^5,4, Francisco Santa Cruz⁵, Dr. Andy Lowther⁶, Dr. Luis Hückstadt⁷, Michael Dinniman⁸, David Donoso^1,4

¹Austral University of Southern Chile, Valdivia, Chile. ²IDEAL Center, Valdivia, Chile. ³COPAS-COASTAL, Concepcion, Chile. ⁴Millenium Institute BASE, Santiago, Chile. ⁵INACH, Punta Arenas, Chile. ⁶Norwegian Polar Institute, Tromsø, Norway. ⁷University of Exeter, Exeter, United Kingdom. ⁸Center for Coastal Physical Oceanography - Old Dominion University, Norfolk, USA

Abstract

Harmony Point in the South Shetland Islands is a region that hosts a diverse number of marine predators and has been previously defined as a biological hotspot. This study explores the role of ocean circulation and bathymetry in the formation and maintenance of a localized area of rich biological production. Harmony Point is off a submarine canyon that connects the area north of the SSI to the Bransfield Strait. During summer 2022 Weddell seals and chinstrap penguins were instrumented with SRDL-CTD and GPS tags respectively. Additionally, during 2023 Weddell seals were instrumented with fluorescence CTDs. The habitat utilization of the 2 species was compared to ocean circulation patterns. To estimate ocean circulation, a high-resolution (1.5 km) model that included tidal dynamics was implemented for the Antarctic Peninsula using the Regional Ocean Modeling System (ROMS). Advection, ocean retention and dispersion from the hotspot at Harmony Point were estimated using Lagrangian particle simulations. The effect of the bathymetry was explored by running simulations using an improved ocean depth and comparing the change in ocean circulation afterward. The results showed that when bathymetry was improved there was formation of regions of ocean recirculation with high kinetic energy that were consistent with the habitat utilized by Weddell seals and chinstrap penguins. Lagrangian simulations showed that Harmony Point receives inputs primarily from the Bransfield Strait and that tidal currents were strong and influenced the transport of particles across the study region. These results provide insights into the dynamical mechanisms that contribute to the formation and maintenance of biological hotspots in the north Antarctic Peninsula.

969

Modeling Pygoscelis penguin demography without banding data

Clare Flynn¹, Ignacio Juarez Martínez^2,3, Tom Hart³, Heather Lynch¹

¹Stony Brook University, Stony Brook, USA. ²Oxford University, Oxford, United Kingdom. ³Oxford Brookes University, Oxford, United Kingdom

Abstract

There is a paucity of data of Adélie (Pygoscelis adeliae), gentoo (P. papua), and chinstrap (P. antarctica) penguin demography on the Antarctic Peninsula and South Shetland Islands because of the lack of banding studies. Our project uses reproductive success calculated from an extensive time-lapse camera network and from published literature, as well as census counts of nests and chicks, to estimate age-specific demographic parameters (i.e. survival, breeding propensity, and breeding success) for each of the three Pygoscelis species. Using age-structured state space models and approximate Bayesian computation methods, we show that we can estimate the vital rates of populations with varying degrees of success. The use of time-lapse cameras to study pygoscelid penguin colonies has become more widespread, so in this study we report on the extent of how useful camera traps are for informing these demography models. We also do a spatial analysis of the demographic vital rates produced by the models to evaluate the degree of spatial autocorrelation of each parameter for each species. These methods are a promising new way of understanding demography without the use of flipper bands, and the results give novel insights into the amount of spatial autocorrelation of survival, breeding propensity, and breeding success rates among Pygoscelis penguin populations.

971

The recent decline and future evolution of a caldera-filling glacier near Pucón

Jan Erik Arndt¹, Marcelo Somos², Alvaro Cruces², David Farias¹, Mario Lillo¹, Hongjie Xie³, Alfonso Fernández¹

¹Universidad de Concepción, Concepción, Chile. ²Universidad de la Fronterra, Temuco, Chile. ³University of Texas San Antonio, San Antonio, USA

Abstract

Sollipulli Volcano, located at about 39° S in the Chilean Andes, is one of only few sites worldwide where a caldera is filled by glacier ice. After retreat of its last glacier tongues, today the glacier is located entirely within the caldera (diameter of about 4 km), with a nearly constant elevation of about 2100 m. Available data suggest a maximum ice thickness of approximately 750 m, making it the deepest measured body of ice in Chile north of the Patagonian Ice Fields, thus harboring a vast amount of freshwater. Glaciers in the southern Andes are generally undergoing fast retreat in recent decades which results in reduced freshwater storage, contribution to sea-level rise, and to formation of glacial lakes, implying the risk of glacial lake outburst floods (GLOFs). For the glacier on Sollipulli, however, no detailed glaciological study has been conducted, despite its unique geometry, size and location.

We used remote sensing data and field measurements to reveal the mass balance evolution of Sollipulli glacier in the last decades. While the glacier was already losing mass in the 2000 – 2015 period, our results show a nearly two-fold increase in melt rates since then, resulting in more than 60-m glacier thinning during the 21st century. This increasing melt coincides with observations of late summer snow absence on the entire glacier, which indicates that the equilibrium line altitude has risen above the maximum glacier surface altitude. We discuss the future fate of the caldera-filling glacier with a focus on its special geometry, including implications for downstream freshwater supply and the hazard potential of newly forming lakes.

975

Pygoscelis penguin colonies occupy differing oceanographic and terrestrial niches

Katherine Gallagher¹, Rachael Herman¹, Katherine Walton², Michael Dinniman³, Heather Lynch¹

¹Stony Brook University, Stony Brook, USA. ²University of California Berkeley, Berkeley, USA. ³Old Dominion University, Norfolk, USA

Abstract

Pygoscelis penguins interact with both terrestrial and marine environments, especially during the austral summer when they raise their chicks. Accessible bare rock spaces serve as locations for penguins to build colonies and successfully raise chicks while the surrounding marine environment serves as the foraging grounds for adult birds. Penguins must be able to navigate through the waters around their colonies to forage for Antarctic krill (Euphausia suberba), their primary prey during the austral summer. Krill, whose distributions are driven partially by the surrounding physics and partially by their behaviors, must also be plentiful in the waters surrounding the colonies to support foraging penguins. Here, we test the hypothesis that terrestrial and oceanographic variables can describe habitat suitability for Pygoscelis penguins along the West Antarctic Peninsula (WAP) during the austral summer and hypothesize that dynamic oceanographic variables (krill, currents, sea ice) are the major drivers of habitat suitability for these species. We built habitat suitability models using logistic regressions using a variety of datasets. Model performance was high (Area Under the Curve > 0.85) across all species. While jackknife analysis suggests that terrestrial elevation is the single most important variable for some species, variables such as spring sea ice extent, prey persistence, and nearshore current velocities also were major contributors to the model across the Peninsula. At individual locations, oceanographic variables comprised of approximately 45-50% of the total predictive terms for Adelie and chinstrap penguins, and as much as 60% for gentoo penguins. Different oceanographic variables made up most of this oceanographic term for different species, suggesting that the species select for different oceanographic niches near breeding colonies. Understanding the major habitat suitability drivers for Pygoscelis penguins today will help us understand how habitat suitability will change in future climate conditions.

977

Quantifying Potential Marine Debris Sources and Potential Threats to Penguins on the West Antarctic Peninsula

Katherine Gallagher¹, Megan Cimino², Michael Dinniman³, Heather Lynch¹

¹Stony Brook University, Stony Brook, USA. ²University of California Santa Cruz, Santa Cruz, USA. ³Old Dominion University, Norfolk, USA

Abstract

Marine pollution is becoming ubiquitous in the environment. Observations of pollution on beaches, in the coastal ocean, and in organisms in the Antarctic are becoming distressingly common. Increasing human activity, growing tourism, and an expanding krill fishing industry along the West Antarctic Peninsula all represent potential sources of plastic pollution and other debris (collectively referred to as debris) to the region. However, the sources of these pollutants from point (pollutants released from discrete sources) versus non-point (pollutants from a large area rather than a specific source) sources are poorly understood. We used buoyant simulated particles released in a high-resolution physical ocean model to quantify pollutant loads throughout the region. We considered non-point sources of debris from the Antarctic Circumpolar Current, Bellingshausen Sea, Weddell Sea, and point source pollution from human activities including tourism, research, and fishing. We also determined possible origins for observed debris based on data from the Southern Ocean Observing System and Palmer Long-Term Ecological Research program. Our results indicate that point source pollution released in the coastal Antarctic is more likely to serve as a source for observed debris than non-point sources, and that the dominant source of pollution is region-specific. Penguin colonies in the South Shetland and Elephant Islands had the greatest debris load from point sources whereas loads from non-point sources were greatest around the southernmost colonies. Penguin colonies at Cornwallis Island and Fort Point were exposed to the highest theoretical debris loads. While these results do not include physical processes such as windage and Stokes Drift that are known to impact debris distributions and transport in the coastal ocean, these results provide critical insights to building an effective stratified sampling and monitoring effort to better understand debris distributions, concentrations, and origins throughout the West Antarctic Peninsula.

979

The Polar Lodge: a Resilient Temporary Shelter in Antarctica

Emeritus professor Susan Roaf¹, Professor Manuel Guedes²

¹Heriot Watt University, Edinburgh, United Kingdom. ²Instituto Superior Técnico, Lisbon, Portugal

Abstract

In 2019 The Polar Lodge 2 team of the Portuguese Propolar organisation constructed a temporary, portable shelter on a rocky promontory at Collins Bay on Kind George Island, Antarctica. Designed to test exactly how resilient a temporary structure can be, it was based on the form and timber structure of a Mongolian Yurt, and used three skins, two external and one suspended internal lining of innovative materials. The aim of the project was to learn more on how to design for the extreme cold and wind conditions on the site and to provide a safe refuge for people from all stations working in the field in the area. Originally hoped to stand for twelve months it las remarkably lasted over five years with minimal damage to the inner two linings although the external Dyneema cloth was damaged in an extreme storm in late 2023. This has allowed the thermal performance of the tent to be monitored during three field work periods in 2019, 2020 and 2024. This presentation covers the history, construction, and data recorded in the field and will discuss the lessons learnt over the five years of the project about resilient design in Antarctica. These were often unanticipated and included new insights into the form, materials, design, construction and siting of the tent at both its design, its fabrication and its building stages. This paper outlines the main steps in that design learning and the unique partnership between ProPolar, Heriot Watt University and INACH who provided the Escudero base and the Logistics for the project that enabled the project to succeed.

981

Long-Range Wireless Networks for Ineternet of Extreme Things

Huicheol Shin¹, Seungjae Baek¹, wooyong Lee², Keunyoung Kim², Younggyun Kim³, Sunggoo Cho⁴, junghwan yoon⁵

¹Korea Institute of Ocean Science and Technology, Busan, Korea, Republic of. ²ETRI, Daejeon, Korea, Republic of. ³WIZNOVQ, Seongnam, Korea, Republic of. ⁴SMK, anyang, Korea, Republic of. ⁵FHT, Daejeon, Korea, Republic of

Abstract

Accessing environmental data from remote areas in Antarctica is crucial for understanding its unique ecosystems and climate. In this work, we propose the implementation of a long-range wireless network to facilitate data collection from regions with limited human access, supporitng the concept of internet of extreme things (IoET). We have developed communication equipment for wireless transmission of collected environmental data and for remote control of unmanned exploration robots in Antarctica. Since each equipment is installed in locations with limited access, we have developed IoET device and gateway for data collection, storage and power control, as well as large capacity battery suitable for extreme environment. Consquently, each device can be powered on/off according to user requirements, enabling prolonged operation. The developed equipment is deployed at three control points: Jang Bogo station, Mount Melbourne, and Browning Pass. Each control point acts as a relay, transmitting data collected from nearby observation stations to server at jang Bogo station. The communication distances between Browning Pass and Mount Melbourn, and between Mount Melbourn and Jang Bogo station, are 50km and 35km, respectively. By establishing a reliable long-range communication network covering these distances, we demonstrate the feasibility of utilizing long-range wireless networks for IoET applications in Antarctica, thereby enhancing environmental monitoring and scientific research in challenging environments.

984

Biogeochemical influence on glacier meltwater composition during summer in coastal Antarctica

Dr. Gautami Samui^1,2, Dr. Runa Antony^1,3, Ms. Aritri Sanyal¹, Dr. Meloth Thamban¹

¹National Centre for Polar and Ocean Research, Vasco, India. ²Savitribai Phule Pune University, Pune, India. ³GFZ German Research Centre for Geosciences, Potsdam, Germany

Abstract

Glacier meltwater discharge into fjords in coastal Antarctica during summer raises questions about the potential downstream effects of the associated release of organic carbon and nutrients. We present chemical changes in supraglacial meltwater over 30 days of austral summer, along a 1.2 km transect, starting from the ice cap margin in Larsemann Hills and traversing through a melt pool and cryoconite holes before discharging into the fjord. The elapsed time of isolation of cryoconite hole from the surrounding hydrological systems (Δt), estimated using the Cl¯ concentration revealed that the cryoconite holes in this region are hydrologically connected and contribute to the meltwater discharge in the region. Dissolved organic matter (DOM) in the cryoconite hole water contained more humic content (UV-humic and visible-humic) than protein (tyrosine). Meltwater-sediment interactions contributed to enhanced concentrations of Ca²⁺ and K⁺, which was supported by high concentrations of both the ions in the cryoconite sediments. The melt pools, due to higher residence time of meltwater, supported greater sediment dissolution and microbial activity (primary production rate: 2.96 mgC L^-1 d^-1), resulting in high concentrations of dissolved organic carbon and nutrients like iron (Fe) compared to the flowing streams in the transect. Presence of micronutrients like Fe in the meltwater is attributed to dissolution of Fe-rich minerals like biotite in the glacier supraglacial sediment. DOM composition in the meltwater shifted from high molecular weight and protein-like (tyrosine) to low molecular weight and humic-like as the summer progressed. Overall, glacier discharge is estimated to transport 3.82 kg km^-2 a^-1of dissolved Fe and 53.2 kg km^-2 a^-1 of organic matter to the coastal Antarctic fjords. Thus, glacier meltwater discharge could have important biogeochemical implications for downstream ecosystems like fjords.

986

Patterns of air mass incursions from Southern Ocean play a role on microbial dispersions into West Antarctic Ice Sheet

Amanda Bendia¹, Renato Romano¹, Julio Moreira¹, Emanuele Kuhn¹, Juliana Ferreira¹, Sérgio Gonçalves Jr.², Camila Signori¹, Natascha Bergo¹, Egberto Pereira², Heitor Evangelista², Vivian Pellizari¹

¹Oceanographic Institute at University of São Paulo, São Paulo, Brazil. ²State University of Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

The cryosphere microbiomes are mostly inoculated by airborne microorganisms, which can accumulate year by year over the accreted snow. In Antarctica, the large-scale aeolian dispersion patterns remain unclear, especially throughout the interior of the continent. Due to the past evidence of sea salt aerosols passing across the Antarctic Peninsula (AP) to the interior of the West Antarctic Ice Sheet (WAIS), our study hypothesized that, likewise, marine microorganisms could be long-range transported through the Antarctic troposphere. For this purpose, we constructed an excavated 2m-depth pit named “Criolab’ in the surroundings of the Brazilian Criosfera1 module (over the WAIS) to collect snow and firn samples for microbial diversity analysis, together with snow and airborne microparticle measurements and air masses backward trajectories modelling. We found a discontinuous profile of microbial taxa abundances and diversity, which is likely a result of the air mass back trajectories changes that carried microorganisms from distinct Antarctic sources during an estimated period of 4 years. Our study indicates that different marine groups, such as SAR11, Idiomarina, and Nitrosopumilus, are shared between the WAIS snow and AP seawater communities, suggesting they are long-range transported over Antarctica. Considering their low and interspersed abundances, we postulate a pre- and post-depositional selection in the face of the extreme atmosphere and cryosphere conditions. Our observations have profound implications for the understanding of the aeolian dispersion patterns over Antarctica, indicating the importance of the marine microbiomes in seeding the interior of the continent.

988

Ecotourism in the Polar regions (Arctic and Antarctic): A Post-Pandemic Approach for Global Environmental Sustainability

DR. DROUPTI YADAV

Assistant Professor and Coordinator, Environmental Science and Technology & IIRS, ISRO Outreach Network Centre, SLSBT, Chhatrapati Shahu Ji Maharaj University,, Kanpur, Uttar Pradesh, India

Abstract

In the global scenario after post pandemic the pressure on the north and south poles accelerated due to the fast growing population, industrialization and urbanization. Among all the techsavy and nature loving behaviour of the human beings posed much pressure in the polar regions too. In-spite of various types of disasters (like natural and anthropogenic) remoteness, extreme weather conditions, and climatic vulnerability of polar ecosystems these regions are famous for iconic landscapes with natural beauty, diverse wildlife, and natural and cultural heritage, hold immense appeal for ecotourists seeking authentic and immersive experiences with lots of joy and satisfaction. The pristine and fragile ecosystems of the North and South Poles present unique opportunities and challenges for ecotourism development in theses extre event areas. These strategies encompass sustainable tourism planning, stringent environmental regulations, community involvement, and visitor environmnental education awarness.

Furthermore, leveraging Remote Sensing and GIS technology and digital technology for virtual tourism experiences can complement physical visits up to some extent, reducing ecological footprints while expanding accessibility and inclusivity. Indigenous communities in polar regions play a vital role as custodians of ancestral lands and invaluable repositories of ecological wisdom. Empowering indigenous peoples in ecotourism decision-making processes fosters cultural preservation and social equity. Moreover, public- private-partnerships between governments, non-governmental organizations, tour operators, and scientific institutions are essential for implementing effective ecotourism strategies and monitoring. By integrating scientific research, conservation efforts, and tourism development, stakeholders can ensure that ecotourism in polar regions contributes to biodiversity conservation, ecosystem, climate resilience, and local livelihoods. By harmonizing economic wellness with ecological balance and social well-being, ecotourism can foster a deeper appreciation for polar environments and inspire collective action to preserve these pristine wilderness areas for future generations.

Keywords: Ecotourism, Sustainable Development, Environment, Conservation, Management, RS & GIS Technology

989

Comparative Study of the annular and partial solar eclipse of 29 April 2014 over Antarctica and Australian sectors

Dr. Pramod Kumar Purohit, Dr Roshni Atulkar, Dr Bhupndrae Malvi

National Institute of Technical Teachers' Training and Research (NITTTR), Bhopal - 462002, M.P., India, Bhopal, India

Abstract

On April 29, 2014, an annular and partial solar eclipse was seen across Antarctica and Australia. We have examined the ionospheric reaction to this solar eclipse event in our work. To determine the changes in several ionospheric parameters during the solar eclipse event over Australia and the Antarctic area, we have conducted an extensive investigation. In this study, we selected four Australian stations: Brisbane (27.5° S, 152.9° E), Canberra (35.3° S, 149.1° E), Hobart (42.9° S, 147.3° E), and Perth (31.955° S, 115.859° E), as well as one Antarctic station, Mawson (70.6455° S, 131.2573° E). We investigated variations in the E and F ionospheric layers using ground-based measurements from these stations. Based on our investigation, we discovered that at all four Australian sectors, the critical frequencies of sporadic E (foEs) and F (foF2) layers decreased while the value of foF2 increased at Antarctica during the eclipse. Simultaneously, there was also a rise in these layers' corresponding heights (ℎ′ Es, ℎ′ F2).

Keywords: Critical frequency (foF2), sporadic 𝐸, ionospheric parameters, Annular solar eclipse.

991

ANTARCTIC FISH Harpagifer antracticus AS CLIMATE CHANGE SENTINEL

PhD Luis Vargas-Chacoff^1,2,3, PhD Kurt Paschke^4,3,5, Ms Daniela Nualart^1,2,3, PhD Jorge M. Navarro^1,3, PhD Steve McCormick⁶, PhD Pedro Guerreiro⁷

¹Instituto de Ciencias Marinas y Limnológicas, U. Austral de Chile, Valdivia, Chile. ²Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantártico (BASE),, Santiago, Chile. ³Centro Fondap IDEAL, Valdivia, Chile. ⁴Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantártico (BASE),, Puerto Montt, Chile. ⁵Instituto de Acuicultura, Sede Puerto Montt, Universidad Austral de Chile, Puerto Montt, Chile. ⁶Department of Biology, University of Massachusetts, Amherst, Massachusetts, Massachusetts, USA. ⁷Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal

Abstract

The climate change is modifying the temperature, the IPPC (2022) and some research projected increase of the temperature from 1 to 8 °C within the next 100 years as response of the climate change. It will cause increases in temperature of the oceans, and especially in Antarctic as stable area. Also, as consequences of increasing temperature in Antarctic or high latitudes will be producing melting of iceberg called “freshening”, and it will be producing changes of the salinity of sea water. Some authors described mean of intertidal temperatures ranged from –4 to +11.8°C in Rothera Research Station (Adelaide Island, Antarctic Peninsula) and other authors in 2018 reported temperatures up to 3 °C for shallow benthic environments in King George Island, which could be affecting at invertebrates and fish. The Harpagifer antarcticus called the spiny plunderfish is an Antarctic notothenioid fish, they are small (7–15 cm standard length) and benthic fishes generally characterized by narrow and shallow bathymetric ranges that inhabits shallow waters (0-20 m), also characterized for being a stenothermic species and constitutes an important trophic resource for Antarctic coastal fish. The aim of this study was evaluate the several abiotic variables on physiology of H. antarcticus as sentinels of climate change. Our results show us that H. antarcticus is affected by variables as temperature, salinity and hypoxia, also stimulant as LPS and POLY:C, and the combined effects of temperature with salinity and stimulants. As conclusion H. antarcticus is a good sentinel specie of climate change. Funding and support: Fondap-Ideal 15150003 and ANID-Millennium Science Initiative Program-Center ICM-ANID ICN2021_002; Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantártico (BASE), PROPOLAR-Programa Polar Português, Project Antarctic-D-Light.

992

Spatial and temporal variations of Antarctic microbial interactions - a study at the western Antarctic Peninsula

Dr. Swan Li San Sow¹, Dr. Henk Bolhuis¹, Dr. Jeremy J. Rich², Prof. Michael P. Meredith³, Prof. Hugh W. Ducklow⁴, Prof. Linda Amaral-Zettler^1,5,6, Dr. Julia C. Engelmann¹

¹NIOZ Royal Netherlands Institute for Sea Research, Den Burg, Netherlands. ²University of Maine, Walpole, USA. ³British Antarctic Survey, Cambridge, United Kingdom. ⁴Columbia University, New York, USA. ⁵University of Amsterdam, Amsterdam, Netherlands. ⁶Marine Biological Laboratory, Woods Hole, USA

Abstract

The Southern Ocean is a critical region of the oceanic overturning circulation that supports global nutrient recirculation and primary production. Coastal waters that surround the Antarctic continent feature rich marine ecosystems and are highly productive yet strongly influenced by seasonality and inter-annual variability. The western Antarctic Peninsula (WAP) has exhibited rapid changes in oceanographic conditions leading to shifts in productivity and microbial community composition. To better predict the implications of temporal variability and future climate change conditions on the microbial community composition, productivity, and community resilience, we explored the inter- and intra-domain interactions between microbes, and microbial-environmental interactions from ~198 surface water samples (3.0 µm and 0.2 µm sequentially filtered biomass fractions). The samples encompass all seasons from two time-series sites at the WAP (Palmer and Rothera) that span a climate gradient. Using high-throughput amplicon sequence datasets, we predicted bacterial and microbial eukaryotic community interactions using a causal (directional) network reconstruction approach. We found seasonal variations in community composition patterns and interactions, with unique seasonal patterns observed at each site. Overall, bacterial-bacterial interactions were dominant. The ratio of other intra- and inter-domain interactions were variable across sampling sites and size fractions, with some of the strongest interactions involving SAR11 clade II, dinoflagellate Prorocentrum sp., Phaeocystis antarctica and multiple groups of parasitic Syndiniales. Temperature was observed to have strong effects on the Palmer community, while salinity and silicate played more dominant roles in influencing the Rothera community further south. These findings provide significant insights towards better understanding the interactions and assembly processes of the WAP microbes throughout the year.

994

Modelling the Southern Patagonia Icefield at the end of the Little Ice Age

Dr. Ilaria Tabone^1,2, Dr. Johannes Fürst¹, Dr. Marius Schaefer³, Prof. Dr. Matthias Braun¹

¹Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany. ²Universidad de Concepción, Concepción, Chile. ³Universidad Austral de Chile, Valdivia, Chile

Abstract

Covering approximately 13000 km2, the Southern Patagonia Icefield (SPI) is the largest ice body of the Southern Hemisphere, second only to the Antarctic Ice Sheet. Estimates from radar interferometry suggest that the SPI has lost mass at a rate of 12 Gt/yr for the decade 2000-2012, representing the largest contribution from Southern Andes to sea-level rise. Overall, information from trimlines and terminal moraines suggests that the mass loss has markedly increased since the Little Ice Age (LIA). This is associated with asynchronous and spatially-heterogeneous past area changes, indicating an overall glacier retreat of 15-20% from the maximum LIA extent. Modelling efforts are therefore crucial to identify the main drivers of such an extensive mass loss, allowing to separate the role of ice dynamics from surface ablation in this centennial recession. Here we present a preliminary modelling experiment to simulate the SPI at the end of the LIA. To this end, we use the three-dimensional, thermomechanically coupled ice-flow model Yelmo. This model has been successfully applied to both the Antarctic and the Greenland ice sheets, and it is here applied for the first time to a temperate icefield. The model is embedded with a high order solver, suitable for fast flowing glaciers, and it is coupled to a glaciostatic adjustment scheme, to account for glacial uplift. Specific attention is given to the calibration of the basal friction and the calving laws, being crucial to describe, respectively, the glacier basal conditions and the dynamic mass loss from the numerous glaciers ending in fjords/lakes. The results presented here are the basis for a long centennial run spanning from the end of the LIA to the present.

1001

McMurdo Dry Valleys Stream Hydrologic Response to Annual Climate Variability

Prof Michael Gooseff¹, Anna Wright¹, Jared Collins¹, Kathleen Welch¹, Prof Peter Doran², Prof Diane McKnight¹

¹University of Colorado Boulder, Boulder CO, USA. ²Louisiana State University, Baton Rouge, LA, USA

Abstract

Streams integrate processes occurring within their catchments, and in the glacial meltwater streams of the McMurdo Dry Valleys (MDVs), Antarctica, streamflow magnitude and duration are directly influenced by source glacier conditions (i.e., albedo and surface roughness) and meteorological conditions that generate melt. MDV streams flow for 6-12 weeks during the austral summer, and are important vectors of liquid water, energy, and biogeochemical solutes to closed basin lakes on the valley floors. Each day they experience a “flood wave” of meltwater, the timing of which is dictated largely by the daily pattern of solar exposure on the source glacier and channel hydraulics. Streamflow increases its solute load as water moves downstream due to dissolution of surface salts early in the flow season, and rapid weathering of streambed sediments throughout the flow season. Streambed sediments (within the hyporheic zone) also serve to store and regulate stream nutrient fluxes. Here we evaluate the responses of streamflow dynamics and chemistry in response to climatic forcing over 20+ years of record in streams across the MDVs.

1002

Role of upper ocean processes on the Formation of extreme warming events in the Antarctic Sea during 2016-2017

Dr. Arnab Mukherjee¹, Mr. Ananthu Pradeep^1,2

¹National Centre for Polar and Ocean Research (NCPOR), Vasco Da Gama Goa, India. ²CSIR - National Institute of Oceanography, Goa, India

Abstract

This study discusses the seasonal and interannual variability of sea surface temperatures (SST) and sea ice concentration (SIC) of the Antarctic Sea during the summer season. The study utilizes a coupled ocean sea-ice model called the Modular Ocean Model of version 5 with Sea Ice Simulator (MOMSIS) and Advanced Very High-Resolution Radiometer (AVHRR) data. The Antarctic Sea has been divided into five sectors, which include the Weddell Sea (WS), Indian Ocean (IO), Pacific Ocean (PO), Ross Sea (RS), and Bellingshausen and Amundsen Seas (BS).

Using both AVHRR and MOMSIS, it has been observed that a strong increase of SST and decrease of SIC in the WS during summertime 2016 is strongly dominated by seasonal variability compared to interannual. However, a strong increase of SST in the BS sector is strongly dominated by interannual variability compared to seasonal. In the other three sectors, the role of both seasonal and interannual variability is significant.

A mixed-layer heat budget analysis was carried out to understand how thermodynamic processes influence variations in SST. It has been noted that the destructive interference between a strong increase of atmospheric heat fluxes and a decrease of oceanic vertical entrainment significantly influences the record increase of mixed layer temperature rate during summertime 2016. Also, a weak but significant increase of ocean horizontal advection has been observed during the summertime of 2016 compared to other years.

1003

Techno-economic analysis of renewable energy generation at the South Pole

Dr. Amy Bender^1,2, Susan Babinec¹, Ian Baring-Gould³, Nate Blair³, Xiangkun Li³, Ralph Muehleisen¹, Dan Olis³, Silvana Ovaitt³

¹Argonne National Laboratory, Lemont, USA. ²KICP, University of Chicago, Chicago, USA. ³National Renewable Energy Laboratory, Golden, USA

Abstract

Renewable energy sources are widely recognized for their ability to provide affordable, reliable energy with reduced environmental impact. We present a techno-economic analysis for implementation of a hybrid renewable energy system at the South Pole, which is home to the Amundsen-Scott South Pole station and a wide-range of scientific experiments. Currently, South Pole station power is supplied by diesel generators and the complex and costly transport of the required fuel. Transitioning to locally-available renewable energy sources presents an opportunity to reduce both negative economic and environmental impacts. We explore a tailored model of resource availability and economics at this site for solar photovoltaics, wind turbine generators, lithium-ion energy storage, and long-duration energy storage in different combinations with and without existing diesel generation. We present the results of this study as well as ongoing work to move towards a conceptual design of a hybrid renewable energy system.

1004

Features of two Ice Sheet Surface warming events in coastal Dronning Maud Land, East Antarctica

Ms Gayathri EM^1,2, Dr Laluraj CM¹, Dr Satheesan K³, Dr Kenichi Matsuoka⁴, Dr Mahalinganathan Kanthanathan¹, Dr Thamban Meloth¹

¹National Centre for Polar & Ocean Research, Goa, India. ²Goa University, Goa, India. ³Cochin University of Science and Technology, Kerala, India. ⁴Norwegian Polar Institute, Tromsø, Norway

Abstract

Over Antarctica, extreme atmospheric warming events have received wide attention due to their importance in surface melting and stability of ice shelves. However, there are few studies of the impact of these atmospheric warming events on the surface and subsurface regime of Antarctica and especially, coastal Dronning Maud Land (cDML). The relationship between near-surface air temperature (T2m) and ice sheet surface temperature (ISST) is not uniform and is dependent on several meteorological conditions like cloud cover and wind speed. Here, we examine two Ice Sheet Surface Warming (ISSW) events with different meteorological conditions over cDML using a borehole temperature record from an ice core (71.5°S, 10.25°E) during the spring of 2015 and 2017. The first event was associated with strong surface easterly winds and high snow accumulation, resulting in T2m warming of ~ 20 °C and ISSW of ~ 11 °C in nine days, where ISSW was attributed to high downward longwave radiation and overlying warmer air as a result of warm air advection from a cyclone. Here, the T2m led by two days with a maximum depth of heat penetration up to 80 cm below the surface. The second event resulted in a T2m warming of ~ 15 °C and ISSW of ~ 5 °C in six days, during strong southeasterly winds without any precipitation, where warming was associated with turbulent mixing from strong, dry and anomalously warm winds from the interior. In this case, the T2m and ISST warmed together with maximum depth of heat penetration up to 60 cm below the surface. The ISSW events can have significant impact on the surface ice conditions with signals penetrating well below the surface. The increase in the duration and frequency of these events in a global warming scenario might alter the physical state of the ice sheet in the future.

1011

Enhancing Telemedical Support in Antarctica Using Extended Reality Technology

Eojin Yi^1,2, Kibeom Yun^2,3, Jinho Jheong^2,4, Il Kim⁵, Jong-Won Hong*^2,6

¹aSSIST University, Seoul, Korea, Republic of. ²Korean Society of Polar Medicine, Seoul, Korea, Republic of. ³Wooridul Green International Hospital, Jeju, Korea, Republic of. ⁴National Medical Center, Seoul, Korea, Republic of. ⁵SurgicalMind, Co. Ltd., Seoul, Korea, Republic of. ⁶Yonsei University College of Medicine, Seoul, Korea, Republic of

Abstract

This study pioneers the development of a remote medical consultation and mentoring using Extended Reality (XR) technology to tackle the extreme challenges faced in the extreme and isolated conditions of the Antarctic. Focused on enhancing medical support quality and safety, the project employs XR to facilitate rapid and effective emergency and medical crisis responses. Initial efforts included developing XR technologies for polar medical emergencies and creating a virtual patient hologram model. The next research phases focused on extending application through field experiments on the Antarctic and advancing XR for comprehensive collaborations. Key achievements encompass adding-on the emergency response protocols and exploring the user's experience, including utilizing Starlink for better connectivity in remote areas. Ultimately, the project aims to introduce a real-time XR-based medical consultation system for the polar regions and other remote conditions such as aerospace, military, and marine medicine.

1012

Manifestations of Political Ecology in Antarctic Environmental Discourse

Giovannina Sutherland

Millennium Institute Biodiversity Institute of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile. Universidad de Chile, Santiago, Chile

Abstract

The Antarctic Continent is a territory dedicated to peace and science. Since the signing of the Antarctic Treaty in 1959, a legal regime has been established that aims at environmental protection and international cooperation. How does the human being relate to nature in this political and legal context?

Political ecology attempts to address the interaction between humans and nature from a perspective of domination, highlighting that power relations determine environmental uses, historically inspired by the exploitation of the natural environment. These are undoubtedly principles that currently do not align with the Antarctic Treaty System. However, new theoretical approaches have emerged from anthropology that complement political ecology and analyze this relationship through the use of practices and discourses as tools for environmental negotiation to obtain power. Genzon argues that human-environment relationships are historically and discursively formed through politics and symbolic instruments. Under this logic, what does the concept of nature mean in the political discourse of the Antarctic Treaty System? How do these practices relate to the soft power of the Antarctic Treaty Parties?

Like these, a series of questions arise around the manifestation of political ecology in Antarctica, challenging us to understand that there are as many interpretations of nature as there are states and societies integrated into the legal regime, and prompting us to identify the existence of power structures in environmental protection discourses.

1013

Evaluating microsleep opportunities for penguins around tourist activities: An exploration with behavior observation data

Yu-Fai Leung¹, Daniela Cajiao², Pablo Tejedo³, Javier Benayas³

¹North Carolina State University, Raleigh, USA. ²Wageningen University and Research, Wageningen, Netherlands. ³Universidad Autónoma de Madrid, Madrid, Spain

Abstract

At the last (2022) SCAR Open Science Conference, we reported results from our study on penguins' behavioral responses to simulated tourist activities, including talking sound, viewing distance, and movement speed. We conducted 106 replicates of passive and active human presence treatments. We found that active human presence consistently triggered significantly higher responses of strong vigilance behavior, and that responses varied between species (Cajiao et al., 2022). In the same study, we also collected data on penguins’ “rest and comfort” (R&C) behavior. The recent work by Libourel et al. (2023) has inspired us to conduct further examination of our data set from the perspective of microsleeps. Using electroencephalographic (EEG) methods, Libourel et al. (2023) found that chinstrap (Pygoscelis antarcticus) penguins took microsleeps of 4 seconds on average, for more than 10,000 times each day. This opportunistic sleeping ability is essential for maintaining their vigilance against predators and other threats. Using our behavior observation dataset (Cajiao et al., 2022), we are exploring a new interpretation of penguins’ R&C behavior as their “best opportunities” to engage in microsleep. We are currently analyzing our dataset to identify proportions and frequencies of R&C behavior segments that are 4 seconds, 8 seconds, and 16 seconds, representing three different levels of microsleep opportunities (MO) (i.e., a 4-second microsleep event can occur in 100%, 50% or 25% of each R&C segment at the three opportunity levels, respectively). In this presentation, we will describe our evaluation method and compare MO’s across simulated tourist activities (talking loud, standing, crouching), viewing distances, and species (Pygoscelis antarcticus and Pygoscelis papua). We believe that our results will provide insights into how tourist activities may affect penguins through microsleep opportunities, and how behavior observation data can complement sophisticated physiological and EEG studies in evaluating penguins’ well-being at popular visitor sites.

1017

BRAZILIAN ANTARCTIC ARCHIVES: WHAT THE INSTITUTIONS KEEP IN THEIR HEARTS?

Dr Gulherme Lopes da Cunha^1,2, Dr Carlos Henrique Tomé³, Dr Ana Flávia Barros-Platiau^4,2, Dr Fábio Albergaria Albergaria de Queiroz², Dr Paulo Câmara^4,2

¹Superior War College, Rio de Janeiro, Brazil. ²Superior Defense College, Brasília, Brazil. ³Federal Senate, Brasília, Brazil. ⁴University of Brasilia, Brasilia, Brazil

Abstract

Brazil does not have territorial claims in Antarctica, although the issue has been at stake in the past. Moreover, the country hesitated before accessing the Antarctic Treaty. Since its first participation in the Antarctic Treaty Consultative Meetings (ATCM), Brazil has had a rather cautious attitude. To what extent does Brazilian participation in Antarctic System bodies adhere to domestic institutional architecture and agency? And how does this adherence affect Brazilian diplomacy and scientific output? This paper seeks to answer this double question based on archives from federal institutions in Brasília and Rio de Janeiro: the Ministries of Foreign Affairs (MRE/DMAE), Defense (MD/SECIRM), and Science, Technology and Innovations (MCTI/CGOA); National Congress; and the Superior War College (ESG). The focus is on the political aspects of the decision-making process at the highest political level (diplomacy and geopolitics). Records and other institutional matters are crucial for the method of process tracing, which involves revisiting official history to retrieve the pieces of the puzzle of Brazilian participation in three Antarctic institutions: the Antarctic Treaty Consultative Meeting (ATCM), Scientific Committee on Antarctic Research (SCAR), and the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). After consulting archives from 2019 to 2024, our main finding is that although Brazil has a clear and decades-old Antarctic policy (POLANTAR) complemented by other federal instruments, the national architecture and agency should be improved to comply with Brazilian priorities, notably concerning climate change. Other findings are: i) The ESG played a key role in the initial phases of Antarctic debates in Brazil; ii) The selected ministries are the most relevant ones; (iii) Brazilian participation varies according to political periods, federal funding and the three Antarctic bodies aforementioned; and (iv) recently, the National Congress gained importance due to the need for funding from the scientific community.

1018

Fine mode aerosols in the Antarctic Peninsula: inter-annual variability and extremes

Eija Asmi¹, Giselle Marincovich², Francisco Quarin², German Pérez Fogwill¹, Pasi Aalto³, Lauriane Quéléver³, Mikko Sipilä³, Aki Virkkula¹

¹Finnish Meteorological Institute, Helsinki, Finland. ²Servicio Meteorológico Nacional, Buenos Aires, Argentina. ³Institute for Atmospheric and Earth System Research, Helsinki, Finland

Abstract

Antarctic cloud formation is climatically very important, yet a poorly understood and characterised process. Aerosol particles affect the cloud formation, life span and physical properties. Depending on the aerosol particle number, size and chemical characteristics, the cloud micro-physical processes and climatic properties can change drastically. Therefore, understanding the baseline aerosol characteristics in the Antarctic atmosphere as well as their extreme values, tricked by external factors such as large-scale meteorology or anthropogenic influences, is of major importance.

We began aerosol measurements in the Argentinean Antarctic station Marambio in January 2013. The observed inter-annual properties of the course mode aerosols have been previously presented (Asmi et al., 2018). Here, we focus on the fine mode (< 1µm) aerosol properties – specifically the aerosol number size distribution measured by a differential mobility particle sizer (DMPS). We have analysed eight years of consecutive size distribution data to reveal the typical concentrations and modal characteristics of the aerosols in Marambio. In addition, we focus on specific events with exceptionally low or high particle concentrations, as compared to the seasonal baseline values. We analyse to what extent the air mass origin, aerosol transport processes and the local meteorological conditions impact the boundary layer aerosol variability.

The main contributor to extreme high number concentrations, when local pollution is neglected, are the new particle formation events. They occur at all seasons but are particularly frequent in summer. Yet, the relative abundance of different aerosol sizes remains rather stable throughout the seasons. Atmospheric temperature and the sea ice processes both correlate with aerosol characteristics. Intrusion of warm, continental air masses also brings aerosols.

Our results provide the basic understanding on aerosol characteristics and behaviour that helps further studies of Antarctic aerosol-cloud interactions and aerosol-climate feedback processes around the Antarctic Peninsula.

1019

Empires, Borders, Impasse: An excessive history of Southern Ocean Governance

Vani Sreekanta

Helmholtz Institute for Functional Marine Biodiversity, Oldenburg, Germany. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany

Abstract

At a time of extraordinary planetary crisis, and after more than two decades of discussions on the Marine Protected Areas in the Southern Ocean (the principal tool of spatial conservation), discussions remain at an impasse. These bordered regimes of management have been difficult to get over the line. This presentation traces the historical dynamics, excessive to the planned zones of conservation, that underscore the logics of contemporary approaches to Marine Governance in the Southern Ocean. By deploying the novel framework of Excess (Peters and Steinberg 2019), to think with the Ocean – its ebbs and flows – which exceed notions of bounded control, this presentation critically examines conservation discourses across spatio-temporal scales.. Using following as a method, this presentation traces the linkages between the empire forests of the imperial British Raj and contemporary Southern Ocean conservation mechanisms to highlight the often-invisible entrenchment of terrestrial imaginaries. Through the telling of a global yet discursively constrained story of the conservation project at the intersection of science, commerce, and empire, this presentation calls for the centering of other imaginations of oceanic spaces. The presentation follows two converging routes: The first delves deep into the historical origins of nature conservation and how bordering has shaped contemporary intergovernmental regimes and control. The second shifts paradigms to examine “western” histories of marine governance and finds itself again in the same place - conservation through international regimes and control through borders.

The flow isn’t always linear, evident, or consistent in form, yet a rhythmic reproduction of power paradigms persists with consequences for the entire planet. This presentation calls for more equitable, and relational marine governance.

1022

THE ROLE OF A FÖHN EVENT IN GLACIER MELT RATES

Carla Puigdomenech¹, Liliana Margonari^2,1,3, Arturo Huber¹, Sebastián Marinsek¹

¹Instituto Antártico Argentino, Buenos Aires, Argentina. ²CONICET, Buenos Aires, Argentina. ³Universidad de Buenos Aires, Buenos Aires, Argentina

Abstract

During the last days of February of 2024, higher positive-degree temperatures and strong winds were registered in different weather stations across the Eastern Antarctic Peninsula. In Vega Island, the analysis of the data of an automated weather station (AWS) located near Bahía del Diablo glacier, showed an increase of ~10 °C above the mean summer temperature and northwesterly winds that reached a speed of 100 km/h during 60 hours (from 27-02-2024 11:00 UTC to 29-02-2024 23:00 UTC). These characteristics, added to a decrease of 15% in humidity, allowed the event to be classified as Föhn.

To quantify the magnitude of the event, data from automatic weather stations located at Matienzo Station (64°58'34"S 60°04'11" W) and in front of Crane glacier (65°18'45"S 62°17'50" W) in Larsen B embayment were analyzed. At Matienzo, a mean temperature of 6.4°C and 57% of humidity during the 28-29 of February was observed. Likewise, the weather station at Crane glacier showed a mean temperature of 6°C and 48% of humidity for the same period. Two days later, a significant temperature drop and increased humidity were observed in both places (Matienzo Station: -2.3°C and 79% of humidity and Crane station: -0.2°C and 79% of humidity).

Annual mass balance is obtained yearly for the Bahía del Diablo glacier using the glaciological method. In order to study the local effects on the mass balance during a Föhn event, we measured the stakes placed across the glacier before and after the event. A loss of around 15cm w.e. of thickness was observed in all the glacier surface from the 25th of February to the 2nd of March. Moreover, the weather and glaciological observations collected present a strong case for the role of föhn winds in the glacial melt rates.

1023

Tracing the Origins of Antarctic Periwinkles: A Molecular Perspective on Laevilacunaria Evolution

Phd(c) Sebastián Rosenfeld^1,2, Phd Claudia Maturana^3,2, Phd Hamish G. Spencer⁴, Phd Thomas Saucède⁵, Phd Paul Brickle⁶, Msc Paula Vidal¹, Phd Moisés Valladares^7,8, Phd Elie Poulin¹, Phd Claudio González-Wevar^1,9,10

¹Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ²Cape Horn International Center (CHIC), Omora Ethnobotanical Park, Universidad de Magellan, Puerto Williams, Chile. ³Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (MI-BASE), Santiago, Chile. ⁴Department of Zoology, University of Otago, Dunedin, New Zealand. ⁵Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6, boulevard Gabriel, 21000, Dijon, France. ⁶South Atlantic Environmental Research Institute, Ross Road, Port Stanley, Falkland Islands (Malvinas). ⁷Laboratorio de Biología Evolutiva, Departamento de Ecología, Facultad deCiencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. ⁸Grupo de Biodiversidad y Cambio Global (GBCG), Departamento de CienciasBásicas, Universidad del Bío‑Bío, Chillán, Chile. ⁹Instituto de Ciencias Marinas y Limnológicas (ICML), Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. ¹⁰Centro de Investigación en Dinámicas de Ecosistemas de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile., Valdivia, Chile

Abstract

The high latitude littorinids include three intertidal and subtidal genera: Laevilitorina Pfeffer 1886, Pellilitorina Pfeffer 1886 and Laevilacunaria Powell 1951. Laevilacunaria comprises 3 shallow-benthic periwinkle species which live around in sub-Antarctic and Antarctic islands of Kerguelen, Crozet, South Georgia, South Orkneys, South Shetlands, extending to the Antarctic Peninsula.This genus is characterized by a life cycle without planktotrophic larvae, and all species of this genus inhabit shallow rocky shores where they may be associated with macroalgae. Thus, this genus represents a very interesting biogeographical model since one species has a wider distribution compared to the others despite the absence of a dispersive larval stage. To understand the origin, systematic, and timing of diversification of Laevilacunaria in the SO, we performed multi-locus molecular phylogenetic reconstruction, species-delimitation analyses, divergence-time estimations, and taxonomical revision. We analysed the three species of Laevilacunaria throughout their entire distribution using three mitochondrial markers (cox1, 12S and 16S) and one nuclear marker (28S rRNA) for phylogenetic reconstruction. We recovered the worldwide phylogeny of the family Littorinidae (167 taxa), and the monophyly of the subfamily Littorininae (Laevilitorina + Laevilacunaria). Also, our results showed that the genus Laevilacunaria and Laevilitorina are not monophyletic, since the species Laevilacunaria bennetti would not form a clade with the other species of Laevilacunaria (L. antarctica and L. pumilio) and would be more related to the species of Laevilitorina that inhabit the Strait of Magellan and Antarctic Peninsula. Additionally, our data suggested that the most recent common ancestor of Laevilacunaria would have occurred during the Palaeogene, followed by much more recent diversification processes during the Pliocene-Pleistocene. Overall, our study integrates molecular and morphological data with biogeographic context, improving our understanding of evolutionary processes in this ecologically important region.

1024

An Early Career Researcher-driven multidisciplinary approach to address future challenges for the Ross Sea

PhD student Simone Di Palma¹, PhD student Angela Garzia², Post-doc Svenja Halfter³, Post-doc Naomi Krauzig⁴, PhD student Nancy Lucà⁵, Post-doc Jasmin McInerney³, PhD student Andrea Molino¹, PhD student Georgia Pollard⁶, PhD student Alessandro Ciro Rappazzo⁷, Post-doc Alina Madita Wieczorek³

¹Department of Science and Technology, University of study of Naples Parthenope, Naples, Italy. ²Department of Civil, Constructional and Environmental Engineering, Sapienza University, Rome, Italy. ³National Institute of Water and Atmospheric Research, Wellington, New Zealand. ⁴Department of Life and Environmental Sciences, Marche Polytechnic University & CoNISMa, Ancona, Italy. ⁵Ca’ Foscari University, Venice Mestre, and ‘’Parthenope’’ University of Naples, Venice, Italy. ⁶University of Waikato, Hamilton, New Zealand. ⁷Ca’ Foscari University, Venice Mestre, and Institute of Polar Sciences, National Research Council (CNR-ISP), Messina, Italy

Abstract

The Ross Sea region is recognised as a crucial area for global climate regulation and a biodiversity hotspot, and serves as a natural laboratory for studying the interconnected effects of climate change on marine ecosystems. This study highlights the vital role of Early Career Researchers (ECRs) in driving forward multidisciplinary research collaborations and innovative strategies for sustained observations and monitoring of the Ross Sea. We aim to enhance the understanding of the physical, chemical, and biological processes critical for global climate regulation and biodiversity conservation by pooling international efforts and resources. Through the lens of the Ross Sea, we discuss the importance of collaborative planning, occurring logistical challenges, and the integration of diverse methodologies essential for effective long-term monitoring. Furthermore, we address the pressing need for sustained funding and support for ECRs, advocating for long-term career stability and the adoption of FAIR data principles to foster global collaboration and knowledge exchange. By showcasing the successful coordination of national monitoring programs and the potential for a "network of networks," this effort underscores the power of international cooperation in bridging observational gaps and enhancing collective responses to climate change and biodiversity loss. This study contributes to the ongoing dialogue on sustainable future strategies, emphasising the Ross Sea's role in informing global climate models and conservation policies. By fostering closer collaboration and knowledge exchange, we aim to inspire future initiatives and networks that support comprehensive and cost-efficient monitoring efforts, ultimately aiding in the global pursuit of climate mitigation and adaptation.

1025

Substantial Antarctic sea-ice loss can contribute to increased occurrence of strong El Niño

Prof. JIPING LIU¹, Dr. Zhu Zhu²

¹School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, China. ²Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

Abstract

Current global climate models project that Antarctic sea ice extent will decrease substantially by the end of this century associated with increasing greenhouse gas forcing. However, it is unknown whether substantial Antarctic sea-ice loss has the potential to influence the frequency of strong El Niño events. Using coupled model experiments, we show that in response to projected nearly half reduction of Antarctic sea ice by the end of this century, the occurrence of strong El Niño is increased by half, as measured by gradient-based indices that remove the mean tropical Pacific warming induced by Antarctic sea-ice loss. However, the projected ice-free Antarctic under a quadrupling of CO₂does not lead to much further increase in the occurrence of strong El Niño. By comparing our coupled model experiments with the greenhouse warming experiments, we show that about two third of the increase of strong El Niño might be associated specifically with Antarctic sea-ice loss. Further experiments that separate Antarctic sea-ice loss and greenhouse gas forcing indicates that substantial decrease in Antarctic sea ice might play an important role in leading to more frequent strong El Niño events.

1029

Atmospheric Drivers of record-breaking low and high temperature events registered at Carlini Station (South Shetlands, Antarctica)

MSc. Alfredo J Costa¹, Dr. Gabriel E Silvestri^2,3, Dra. Ana Laura Berman^2,3

¹Instituto Antártico Argentino (IAA/DNA), San Martín, Provincia de Buenos Aires, Argentina. ²Centro de Investigaciones del Mar y la Atmosfera (CIMA/CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina. ³Instituto Franco-Argentino para el Estudio del Clima y sus Impactos (UMI IFAECI/CNRS-CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina

Abstract

This work aims to analyze atmospheric conditions leading to the record-breaking low and high near-surface air temperatures, for the 1985-2023 period, registered at Carlini Argentine Antarctic Station located in 25 de Mayo (King George) island in the South Shetland Archipelago, to the northwest of the Antarctic Peninsula. The coldest event took place between 23 and 26 July 1994, with a low record-breaking temperature of -27.3°C while the warmest event occurred during 7 and 8 February 2022 reaching a high record-breaking temperature of +13.6°C. Surface observations and atmospheric reanalysis (NCEP/NCAR and ERA5) are used to investigate the drivers of these extreme temperature events. The associated large-scale atmospheric circulation patterns evidence an easterly (northerly) flow which may favor conditions for the occurrence of the coldest (warmest) extreme event. Furthermore, extended sea ice may have played a relative role for the development of the extreme cold temperatures. On the other hand, a noticeable wind speed maximum upstream of the study region may have played a relative role for the development of the extreme warm event through the occurrence of a foehn effect to the south of the Arctowski icefield where Carlini Station is located.

1034

Advancing oceanographic biogeochemical data management towards FAIR compliance with AI potential

Dr Mohamed Adjou^1,2, Ms Joana Beja³

¹ISEN Engineering School, KLaIM-L@BISEN, Brest, France. ²University of Brest, IUEM-UAR3113, Plouzané, France. ³Flanders Marine Institute. Flanders Marine Institute (VLIZ), Oostende, Belgium

Abstract

While machine-generated data from marine sensors come with consistent pre-defined metadata, the logging of marine biological or biogeochemical sample data often involves human processing, leading to free-text descriptions provided as (raw) metadata. We propose here perspectives to optimise data management and better meet FAIR principles by leveraging AI and robust marine metadata norms, aiding from data originators to data managers in efficient annotation. We present a framework for interactive data validation prior to sharing through dedicated repositories, aligning with other data collections, and simplifying the archiving process. This will be facilitated primarily through the application of Natural Language Processing (NLP), aimed at identifying metadata, especially for the wide range of conventional and less common biogeochemical data (substances, matrices, etc.). While the marine biological community already uses tools like GBIF's Integrated Publishing Toolkit (IPT) and the Darwin Core (and its various extensions) respectively. The framework presented in this abstract complements these practices by assisting data providers in submission processes, maintaining FAIRness, and improving interoperability with minimal resource costs terms of human and computational resources.

1036

Foehn winds alter surface dynamics on several ice shelves in Dronning Maud Land

Anirudha Mahagaonkar^1,2, Geir Moholdt¹, Quentin Glaude³, Thomas V. Schuler²

¹Norwegian Polar Institute, Tromsø, Norway. ²University of Oslo, Oslo, Norway. ³University of Liège, Liège, Belgium

Abstract

The attribution of several rapid melt events to the warm and dry downslope mountain winds, known as foehn winds, on Antarctic Peninsula ice shelves (e.g., on Larsen C Ice Shelf) has drawn attention to their significant potential implications, emphasizing the necessity for a comprehensive understanding of this phenomena. Here, for the first time, we show spatiotemporal occurrences of foehn over ice shelves in Dronning Maud Land, East Antarctica, using a high-resolution simulation (5 km) from the regional climate model MAR. These foehn winds are caused by ice rises and promontories acting as topographic barriers to the coastal easterlies, raising lee-side surface temperatures substantially (up to 16°C) with respect to the wind side. Among ice shelves with frequent foehn occurrences (15-30% days/year), Riiser Larsen Ice Shelf was most affected with an average 2.1 ± 1.1°C rise in near-surface temperature during these events. Other regions with frequent foehn occurrences include (in the order of warming induced) Ekström, Roi Baudouin, Muninisen and Nivlisen ice shelves. Significant correlation (r = 0.96, n = 5) between the average temperature rise and the height of the topographic barrier indicates strong dependence of the warming potential of foehn winds on the height of ice rises and promontories. Seasonally, foehn events are more frequent during the extended winter months (February – November), with only 0.5-6.2% occurring during the summer months December and January, limiting the direct impact of foehn on surface melting. However, foehn winds in winter may erode surface snow/firn, deplete firn air content, and set the stage for melting to occur as summer approaches. Except for Ekström Ice Shelf, we find that areas with high foehn occurrence coincide with areas of meltwater ponding in summer, highlighting the potential role of foehn in the development and evolution of supraglacial lakes in parts of East Antarctica.

1042

What a colorful pole: ecology of snow algae blooms in Antarctica

Dr Daniela Soto^1,2, Dr Ivan Gomez^3,2, Dr Pirjo Huovinen^3,2

¹Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia,, Valdivia, Chile. ²Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ³Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile

Abstract

Snow algae blooms are complex microbial communities dominated by green microalgae and bacteria. These communities colonize snowfields during the melting season worldwide and change the snow coloration, reduce albedo and in turn exacerbate snow melting. In Antarctica, during their progression, the assembly of these microbial communities occurs under harsh environmental conditions and a variable nutrient content due to fast snow melting. However, the content of nutrients such as nitrate, ammonium, phosphate, and organic carbon does not play a major role in structuring the microbial community. In contrast, “environmental filtering” might be regarded as one of the mechanisms influencing the assembly of microbial communities in snow algae blooms.

Data obtained from the temporal study of snow algae microbial communities from early stages to colorful blooms in Antarctica revealed that the bacterial composition is governed by selective forces. In contrast, the eukaryotic community assembly is governed by stochastic processes. Selective mechanisms include environmental filtering that selects cold adapted microorganisms while stochastic processes include dispersal limitations and drift. Considering the ubiquitous presence of some snow algae species our results and model propose that the transition from green vegetative cells to red dormant propagules is a key factor in snow algae ecology because it allows the successful in situ reestablishment of algal communities and their dispersion across distant geographical sites. Overall, our results display novel aspects of snow algae ecology, incorporates, and interprets data over years of study and propose a model that can be used to generate further hypotheses regarding the environmental constraints influencing the establishment of snow algae communities.

1047

Evaluating drivers of marine animal mass mortality events recorded in bone piles in the Falkland Islands

Kit Hamley¹, Dulcinea Groff²

¹University of Maine, Orono, USA. ²University of Wyoming, Laramie, USA

Abstract

Southern Ocean biota face numerous threats in their terrestrial breeding environments and the ocean where they feed. At the boundary of the sub-Antarctic frontal zone, the Falkland Islands are a biodiversity hotspot in the western South Atlantic Ocean with a long history of human pressure on the landscape. Degraded, former peatlands in the Falkland Islands have led to the discovery of unique landscape features called ‘bone piles’. The bone piles assemblages are primarily made up of southern sea lions (Otario flavescens) and rockhopper penguins (Eudyptes chrysocome), however recent excavations also revealed southern elephant seals (Mirounga leonina), striated caracara (Phalcoboenus australis) and other seabirds. Recent excavations and radiocarbon dating of O. flavescens bones revealed time patterning that suggests the deaths may have occurred as pulses across time rather than continuous accumulations over thousands of years. Clustering of O. flavescens ages occur at 1,200 calibrated years before 1950 (cal yr BP) and 600 cal yr BP. The bone piles provide an opportunity to test hypotheses about what can lead to pulses of colony extinctions such as mass mortality events related to marine resources, epizootic events, abrupt climate change, extreme events, wildfire, or human impacts. By examining charcoal from peat records, dietary stable isotopes from bones representing multiple species, the archaeological context of the bone piles, and regional climate records, we have begun to disentangle possible drivers of these mortality events. The bone piles represent unique snapshots of marine animals in time that provide valuable clues about the human and the direct and indirect impacts of climate change on sensitive ecosystems in the Southern Ocean.

1052

Frosty resilience: unveiling the silent battle of Antarctic plants in response to extreme environmental challenges

PhD Renato Giliberti, Dr. Elisabetta Bizzarri, PhD Silvia Proietti, Prof. Carla Caruso, PhD Laura Bertini

Dept. of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy

Abstract

Recent alterations in global environmental conditions due to climate change are severely testing resilience and resistance of living organisms, particularly threatening those evolved in ecological niches characterized by prohibitive conditions. Maritime Antarctica is the only place of the White Continent which hosts two endemic vascular plants, Colobanthus quitensis and Deschampsia antarctica, whose ability to react to (a)biotic stresses mainly depends on their reactions to local environmental variables. Thus, the study of their metabolic reprogramming induced by different local stressors will help scientists gain a comprehensive understanding of their physiological responses and predict ecosystem developments. To this end, a differential gene expression analysis was carried out in C. quitensis plants grown at three different sites in King George Island. Going from Site1 to 3, increasing distance from the sea, altitude and exposure to strong winds were recorded.

This study shows that environmental factors can actively influence several plant molecular pathways involved in both development and stress response, also emphasizing that Site2 conditions are less stressful. Mainly, the phenylpropanoid pathway, which produces phenolic compounds that helps plants mitigate oxidative stress and adapt to a variety of environmental challenges, such as salinity, drought, and severe temperatures, was found over-expressed in this site. In addition, several genes related to carbohydrate metabolism and fatty acid degradation were over-expressed, confirming that plants growing in Site2 are characterized by more active metabolic processes. Finally, many differential expressed genes were related to plant microbe-interaction suggesting that plants growing in Site2 are able to counteract biotic stresses by activating the immune response. Overall, this work highlights that one of the three sites shows more favorable environmental conditions than the other two, both in terms of plant resilience and greater stress resistance capabilities, thereby enabling plants to better respond to ongoing climate change.

1053

How close are the Magellan mussels to invade the Southern Ocean under current conditions and projected warming sceneries?

Dr Jorge Navarro^1,2, Dr Leyla Cárdenas^3,2, M.Sc. Alejandro Ortiz², Dr. Luis Vargas Chacoff^1,2, B.Sc. María Araya¹, Dr. Zambra López-Farrán²

¹Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile., Valdivia, Chile. ²Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ³Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile

Abstract

Marine mussels are common members of subtidal and intertidal communities and distributed throughout all continents of the world, except the Antarctic. The physiological capacity to withstand a wide range of conditions can be correlated with a species’ invasive potential. Exploring this capacity in mussel’s species from Magellan region might allow to understand their ability to resist the thermal conditions that currently occur or are foreseen to occur in Antarctica in the future due to climate change.

The aim of this study was to determine the limits of survival of two Magellan species of mussels, Mytilus chilensis and Aulacomya atra, under current Antarctic conditions and those projected under climate change. These assessments were used to define the mussel’s potential for establishment in the Antarctic region. Experimental mussels of both species were exposed to four treatments: −1.5 °C (Antarctic winter), 2 °C (Antarctic summer), 4 °C (Antarctic projected) and 8 °C (control) for 80 days and a physiological approach was used to investigate the mussel’s response.

Similar responses were obtained in both species. The reduced feeding rate and the negative scope for growth, for a large part of the exposure period at −1.5 °C, suggests that Antarctic winter temperatures represents a physiological and environmental barrier to both species to settle in the Antarctic. However, although M. chilensis and A. atra are not able to withstand the current thermal conditions of Antarctica, future warming scenarios are very likely to weaken these physiological barriers. These results strongly suggest that the Western Antarctic Peninsula could become part of the distribution range of these two Magellan mussel species, dispersal favored especially by increased shipping activity across the Southern Ocean.

Funding was provided by Center FONDAP-IDEAL 15150003 awarded by ANID Chile.

1054

Toward identifying Antarctic petrel (Thalassoica antarctica) population differentiation

Kate Blackwell¹, Andrea Elvheim², Dr. Shripathi Bhat², Dr. Kim Præbel², Dr. Sébastien Descamps³, Dr. Heather Lynch¹, Dr. Arnaud Tarroux⁴

¹Stony Brook University, Stony Brook, USA. ²University of Tromsø, Tromsø, Norway. ³Norwegian Polar Institute, Tromsø, Norway. ⁴Norwegian Institute for Nature Research, Tromsø, Norway

Abstract

Antarctic Southern Ocean ecosystems are expected to be strongly affected by climate change in the coming decade, and Antarctic petrels are well-suited for use as indicators of the ecosystems’ changing state. They are in fact one of the indicator species used in the Commission for the Conservation of Antarctic Marine Living Resources’ (CCAMLR) Ecosystem Monitoring Program. With an estimated total abundance of 10‐20 million individuals, the Antarctic petrel is believed to be among the most numerous of Southern Ocean seabird species, and one of the few to span the entirety of the Antarctic. Already, recent declines in the species’ reproductive success (by more than 50% in some areas over the past 30 years) are hypothesized to stem from climate change. Understanding these declines, however, requires a clearer picture of the Antarctic petrel’s large-scale population structure. To begin to assess whether Antarctic petrels are a single panmictic population spanning the entirety of Antarctica or if migration barriers create separate breeding populations, we have developed a reference genome for a female and a male Antarctic petrel and identified whole-genome single nucleotide polymorphism (SNPs) in samples collected from two nesting sites located ca. 100 km apart in Dronning Maud Land (DML). DML Antarctic petrels’ genomic history was characterized by estimating effective population size over time via MiSTI (Migration and Split Time Inference), inbreeding and heterozygosity-fitness correlations. Understanding the Antarctic petrel's population structure has direct implications for the species’ conservation management– population structure is a prerequisite for the Scientific Committee on Antarctic Research and CCAMLR to define conservation units for this species and incorporate them into the design of protected areas– and our understanding of the impacts of large-scale climate change across the Antarctic Southern Ocean.

1057

Assessment of ICESat-2 Ice Surface Elevations in Antarctica based on Multi-sensor Ground Observations

Professor Gang Qiao^1,2, Mr. Hongwei Li^1,2, Mr. Youquan He^1,2, Mr. Yuanyuan Gu^1,2, Professor Tong Hao^1,2, Professor Rongxing Li^1,2

¹Center for Spatial Information Science and Sustainable Development Applications, Tongji University, Shanghai, China. ²College of Surveying and Geo-informatics, Tongji University, Shanghai, China

Abstract

The new photon-counting laser altimetry satellite ICESat-2 was successfully launched and has collected data since 2018 with an unprecedented ice surface elevation accuracy of 2-4 cm. The ICESat-2 mission team has conducted a validation campaign and stated that the data in the flat Antarctic interior met the design requirements. This campaign to validate ICESat-2 data went over a large part of the flat interior of Antarctica along 88°S. However, it should have gone over more of the lower-latitude interior and coastal regions as well to get a full picture of the elevation of different parts of the Antarctic. In this study, we designed and implemented a series of validation campaigns at multiple sites (CHINARE traverse and research stations, multiple coastal sites near Nansen and Rose_point ice shelves). Along with the GNSS and UAV tools, the system had optical corner cube retroreflectors (CCRs) and retroreflective target sheets (RTSs), which were used to test the accuracy of single-photon elevation. The design of this assessment system fully considers orbit accuracy and footprint size, as well as Antarctic expedition conditions. We developed suitable assessment algorithms tailored to the characteristics of ICESat-2 and different sensors. We completed the first systematic evaluation of ICESat-2 along the CHINARE traverse. Overall, the validation results show that the elevation accuracy of the ATL06 is 1.5±9.1 cm along the CHINARE traverse and is accurate to 3.1±8.6 cm as estimated by using UAV-DEM. The elevation of the ATL03 photons has an offset of 1.8 cm from CCRs and is accurate to 2.5±2.7 cm, as estimated by using RTSs. In addition, based on the UAV-DEM, we also evaluated the accuracy of the orbit positioning (2.2-5.8 m). The validation results demonstrate that the estimated ICESat-2 elevations are accurate to 1.5-3.1 cm in East Antarctica.

1058

Intra‐season variations in distribution and abundance of humpback whales in the West Antarctic Peninsula using cruise vessels as opportunistic platforms

Mr Elling Deehr Johannessen¹, Dr Martin Biuw², Dr Ulf Lindstrøm^2,3, Ms Victoria Marja Sofia Ollus³, Dr Lucía Martina Martín López⁴, Dr Kalliopi C. Gkikopoulou⁵, Dr Chris Oosthuizen⁶, Dr Andrew Lowther¹

¹Norwegian Polar Institute, Tromsø, Norway. ²Institute of Marine Research, Tromsø, Norway. ³UiT The Arctic University of Norway, Department of Arctic and Marine Biology, Tromsø, Norway. ⁴Asociación IPAR Perspective para el desarrollo sostenible y divulgación científica IPA, El Allende Llanes, Spain. ⁵Sea Mammal Research Unit, School of Biology, Scottish Ocean Institute, University of St Andrews, St Andrews, United Kingdom. ⁶Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa

Abstract

Fine‐scale knowledge of spatiotemporal dynamics in baleen whale distribution and abundance throughout the Western Antarctic Peninsula (WAP) is sparse yet essential in understanding competition with other top predators such as pinnipeds and penguins. Unfortunately, collecting these data is becoming more difficult due to reduced capacity of national research platforms, increasing costs and reduced funding. Herein, we trial tourist vessels as platforms of opportunity throughout the austral summer of 2019/2020 as a viable way to collect data on cetacean distribution and abundance. We use traditional design‐based line transect methodology and spatial density surface hurdle models fitted using a set of physical environmental covariates to estimate the spatiotemporal dynamics of humpback whales in the area. We show a rapid increase in humpback whale abundance in the Bransfield and Gerlache Straits through December, reaching a stable abundance by mid‐January. The distribution of whales appeared to change from a patchier distribution in the northern Gerlache Strait to a significantly concentrated presence in the central Gerlache and southern Bransfield Straits, followed by a subsequent dispersion throughout the area by mid summer. Abundance estimates agreed well with previous literature, increasing almost threefold between 2000 and 2020. From an ecosystem perspective, a whale population recovering from historical exploitation is likely to modify competitive dynamics within the krill-dependent predator guild. In addition, the suite of additional stressors (e.g. climate warming) facing marine predators in the WAP presents a complex challenge to disentangle what can be directly and effectively managed. To fully understand the current and future effects of such a stressed system, understanding the ecological impact of recovering baleen whale populations which exploit the Antarctic requires prioritization in future work.

1059

Molecular phylogeny and divergence time estimations in Siphonaria (Gastropoda: Siphonaridae) across its distribution in the sub-Antarctic.

Mr Marcelo López-Orellana^1,2,3, Dr Hamish Spencer⁴, Dr Kirsten Donald⁴, Mg. Sc. Sebastían Rosenfeld², Dr. Elie Poulin^2,5, Dr. Claudio González-Wevar^6,2,3

¹Universidad Austral de Chile, Valdivia, Chile. ²Instituto Milenio BASE, Santiago, Chile. ³Centro Fondap IDEAL, Valdivia, Chile. ⁴Department of Zoology, University of Otago, Dunedin, New Zealand. ⁵Departamento de Ciencias Ecológicas, Universidad de Chile., Santiago, Chile. ⁶Instituto de Ciencias Marinas y Limnológicas (ICML), Valdivia, Chile

Abstract

The sub-Antarctic region located between the Subtropical Convergence and the Antarctic Polar Front includes several Southern Ocean (SO) provinces. The presence of remote and geographically distant islands influenced by the Antarctic Circumpolar Current (ACC), make this region an excellent area for biogeographical studies. Across the sub-Antarctic, the pulmonate genus Siphonaria includes several species, two of them (S. lateralis and S. fuegiensis) are broadly distributed between South America and Macquarie Island. Two nominal species of Siphonaria (S. innominata and S. stewartiana) are found in New Zealand sub-Antarctic Islands. Here, we assessed biogeographical patterns in Siphonaria across the sub-Antarctic. Phylogenetic reconstructions using mtDNA markers and divergence time estimations revealed three distinct species-level clades among New Zealand's sub-Antarctic specimens. One of them, corresponds to S. stewartiana and two different species were found within S. innominate individuals. This diversity is closely associated to S. lateralis and S. fuegiensis and differs from those found in New Zealand North and South Islands. Interestingly, a specimen of S. fuegiensis was found at Snares Island, extending the range of this species into the New Zealand sub-Antarctic province. Divergence time estimations suggest that the separation of the sub-Antarctic species of Siphonaria occurred around 4.0 Ma (3.0 to 8.0 Ma). Following this, Siphonaria diversified during the Pliocene and Pleistoecene in New Zealand sub-Antarctic Islands reflecting the role of Quaternary glacial cycles over the biogeography of the genus. Similar patterns to those recorded in Siphonaria are also being found in the bull kelp genus Durvillaea. Species like S. fuegiensis and S. lateralis exhibit broad sub-Antarctic distributions while species in New Zealand Islands appear to be more restricted endemics. This suggests that akin to Durvillaea, Siphonaria species in the sub-Antarctic New Zealand region might found refuge during glacial periods, triggering allopatric speciation processes.

1060

Polar Sleep: Understanding Circadian Challenges and Gender Dynamics

M. Nicolas Van den Berg^1,2,3, Mrs Amélie Rolinat^4,2,3, M. Xavier Next², M. Guido Simonelli^4,3, Mrs Nathalie Pattyn²

¹University of Montréal, department of medecine, Montréal, Canada. ²Royal Military Academy, department of human adaptation, Brussels, Belgium. ³CEAMS Centre d’Etudes Avancées en Médecine du Sommeil, Sacré Coeur hospital, Montréal, Canada. ⁴University of Montréal, department of medicine, Montréal, Canada

Abstract

Context: Disturbances to sleep and circadian rhythms are prevalent in polar environments, particularly when overwintering. Such disturbances include poor sleep quality, sleep fragmentation, seasonal depression, and altered hormone secretion due to lack of day-night cycles. Studies often attribute these sleep disturbances to extreme latitude and seasonality, yet multiple confounding variables have not been ruled out. Specifically, Antarctic crews lack intergenerational isolation experience, in contrast to Arctic residents who encounter the same seasonal disturbances yet are permanent habitants of their environment. Further, sex differences might explain differences in sleep adaptation to these polar environments. We aim to 1) unravel whether sleep disturbances in Antarctica should be attributed to latitude, lived experience, or their interaction; and 2) explore how sleep disturbances in Antarctica and in the Arctic vary by sex.

Methodology: Participants (n=40, matched by sex and age with our existing Antarctica database) will be recruited in Northern Norway during winter and summer solstices. At both seasons, participants will undergo one night of polysomnography, and will provide saliva sampling during a 24-hour period to assess circadian changes in cortisol and melatonin. Actigraphy will continuously monitor sleep-wake activity for 14 days, alongside subjective state reports of sleep quality and mood, and trait questionnaires of psycho-social-environmental factors.

Results: We anticipate that Arctic participants will have a better quality of sleep than Antarctic expeditioners. Regarding sex differences, women will have more nighttime awakenings, phase advanced core body temperature and melatonin rhythms, as well as a shorter intrinsic circadian period compared to men. Bayesian network analysis should show that a lower socio-economic level and a higher isolated environment will further impact sleep.

Discussion: This study will provide evidence on the various factors affecting sleep quality, which can be leveraged to improve adaptability in polar and extreme environments.

1061

The Fragility of the Encounter from the Subantarctic to Antarctica.

Ms Paola Vezzani

Cape Horn International Center, Punta Arenas, Chile

Abstract

To speak of fragility suggests a condition that makes living beings, human and non-human, and ecosystems vulnerable. If we talk of encounters, we can think of the encounters between people, cultures, and diverse living beings in a given place. We can also think of the encounter within our mind, for example, finding or losing in memory. The fragility of the encounter, a more poetic than concrete concept, will be the guiding thread to refer to a group of 4 works, two in public spaces in Chile and Finland. The beautiful and delicate sub-Antarctic and Antarctic ecosystems inspire all of them. Also, with these works, it is possible to allude to the fragility of humanity in the scenario of climate change and loss of biodiversity. Human beings are not isolated from nature. On the contrary, it participates in the web of life on Earth.

The artworks that I will share are made in steel plate, hand cut, and it is possible to recognize trees; whales that are also islands or become forests; ships built with textures that are both maps and vegetation; a lighthouse that, through the openwork wefts in its metal body, lets the inner light through and suggest a forest. As a symbol, the lighthouse invites us to think of a better future made possible by conserving and restoring ecosystems.

I use a delicate weft cut into the steel plate to depict Antarctic landscapes to suggest from emblematic fauna to microscopic life underwater.

As an artist, I seek to convey an invitation to the general public to learn about the reality of Antarctica and the Subantarctic territory and, through emotion, feel the fragility of these places and how vulnerable they can be after encountering human beings.

1062

Using citizen science as a tool to assess Antarctic pack ice seal distributions and habitat preferences in a changing climate

Alyssa Scott¹, Dr. Michael Tift¹, Dr. Dan Costa², Dr. Luis Huckstadt³

¹University of North Carolina Wilmington, Wilmington, USA. ²University of California Santa Cruz, Santa Cruz, USA. ³University of Exeter, Penryn, United Kingdom

Abstract

Atmospheric, oceanographic, and sea ice conditions in the Antarctic are rapidly shifting due to global climate change. Such changes are likely causing a shift in the population dynamics of the dominant prey species, Antarctic krill, which can then lead to fluctuations in the distribution and population of higher-trophic level predators. Across the Southern Ocean, a research gap exists regarding current pinniped species distributions and their links to environmental drivers. Addressing such questions is important to understanding how the pinniped community will respond to the dramatic climatic changes already taking place. The rise in Antarctic visitor numbers over the past decade, coupled with the accessibility of mobile technology such as cell phones and cameras, has presented an opportunity for Antarctic tourists, naturalists, and researchers to capture high-quality marine wildlife images, videos, and location data. Moreover, the widespread use of social media has allowed people to rapidly share and coalesce images of marine wildlife via online networks and citizen science websites. Thus, the increased ability for volunteer citizen scientists to participate in data collection has made citizen science an increasingly important ecological tool. Using a citizen science-derived sightings database spanning over 30 years, this study aims to model the relationship between environmental covariates and the species richness and spatio-temporal distributions of the crabeater seal (Lobodon carcinophaga), leopard seal (Hydrurga leptonyx), Weddell seal (Leptonychotes weddellii), Ross seal (Ommatophoca rossii), and Antarctic fur seal (Arctocephalus gazella) along the Western Antarctic Peninsula. Here we demonstrate how citizen science and modeling can be used to evaluate the distribution and success of remote species, as well as become a highly applicable and useful tool in marine conservation.

1063

Ten years of the Introduction to Antarctic Research Summer school: the next generation of Uruguayan polar researchers.

Dr. Juan Cristina¹, Dr. Demot Antoniades², Dr. Susana Castro-Sowinski¹, Dr. Fernanda Cerdá¹, Dr. Gabriela Eguren¹, Dr. Erna Frins³, Dr. Eduardo Manta⁴, Dr. Gonzalo Moratorio¹, Dr. Pilar Moreno¹, Dr. Rodrigo Ponce de León¹, Dr. Bettina Tassino¹, Dr. Ana Silva¹, Dr. Odile Volonterio¹

¹Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Centre d'Études Nordiques (CEN), Université Laval, Quebec, Canada. ³Facultad de Ingeniería, Universidad de la República, Montevideo, Uruguay. ⁴Facultad de Química, Universidad de la República, Montevideo, Uruguay

Abstract

The main objective of the School of Introduction to Antarctic Research of Facultad de Ciencias, Universidad de la República, Uruguay, is to stimulate the interest of young undergraduate students in Antarctic research. This school is designed for students from different backgrounds who may choose Antarctic research as an option for their curriculum. On the other hand, this school aims to contribute to a university educational program in all fields of Antarctic research as well as to stimulate young scientists to join Antarctic research projects. This is one of the main curricular activities at the higher education level carried out at the Uruguayan Base Científica Antártica Artigas (BCAA) and, to our knowledge, is the only field school focused on Antarctic research for undergraduate university students worldwide. Before applying for the school, the students must complete the “Introductory to Antarctic Research course” at Facultad de Ciencias. This course is a one semester theory course that covers all areas of Antarctic research. Field and lab activities are then held at BCAA, in a multidisciplinary approach by a team of eight professors of different disciplines. The didactic methods applied by the school prioritize active learning and problem solving centered around each student. In its 2014, 2016 and 2018 editions, the School of Introduction to Antarctic Research took place for a total of 70 students in biology, biochemistry, human biology, natural resources, and geology. The fourth edition, programmed for the 2024/2025 campaign, will add students from physics, chemistry and anthropology. In addition to joint field activities, the students were divided into different lab modules, including physics, chemistry, chronobiology, aquatic ecosystems, climate evolution, microbiology and invertebrate diversity and biogeography. The results obtained from activities at the BCAA are presented by students upon their return to Uruguay in order to obtain the corresponding credits for their degrees.

1067

Antarctic education outside Antarctica. Transdisciplinary teaching experience in research on Antarctic issues in a secondary school

Doctora Claudia Soto García¹, Profesora Constanza Abarca Ramos², Profesora Rosa Paulsen Encalada², Profesora Valentina Valdivia Ortiz³

¹Universidad Católica Silva Henríquez, Santiago, Chile. ²Colegio Bicentenario Antártica Chilena, Santiago, Chile. ³Universidad de Barcelona, Barcelona, Spain

Abstract

Transdisciplinary dialogue is relevant for the development of knowledge and learning beyond the disciplines, allowing the study of complex problems such as environmental issues, which impact sensitive and distant ecosystems for most of the population: ecosystems such as the Antarctic, which are crucial for global biogeochemical balance. Thus, the need arises to make it visible, especially at school, to raise awareness among students about the planetary effect of their habits and behaviors, later carrying this learning into their adult lives. This communication relates a pedagogical experience and shows the results of a case study that implements and evaluates a transdisciplinary research strategy on Antarctic issues with high school students from the Colegio Antártica Chilena, located in Santiago de Chile. The objectives were: 1) To guide, with teachers from the humanistic and scientific area, six groups of students in the development of research projects on Antarctic topics; 2) To evaluate results of: conceptual knowledge integrated from the humanistic and scientific area, in relation with Antarctic and environmental themes; emotional and cognitive skills; and pro-environmental behavior. Data collection was carried out by applying interviews and questionnaires to students, written works of their research, teachers' stories about their experience, and class observation diaries. A qualitative content analysis was carried out using Atlas ti software. From this analysis, the results show progress in the integration of disciplinary areas in terms of scientific methodology, critical-reflective writing and reading; the motivation towards Antarctic issues; the development of cognitive skills such as teamwork, perseverance, and organization; emotional in terms of empathizing with Antarctic problems and with the diversity present in their investigative teams. Finally, it is necessary to strengthen students' scientific theoretical knowledge, which requires more in-depth prior instruction.

1068

Antarctic School Fair: 20 years of collaborative science at the secondary school level

Andrea Peña, Reiner Canales, Jessica Paredes, Constanza Jiménez

Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

Understanding Antarctica as a continent of the future means not only accepting its potential to transform and determine the future of the planet, but also the challenge of communicating this relevance to those who will be responsible for its protection: the next generations.

For this reason, stimulating motivation and interest in understanding and protecting this territory among young people from an early age has been an objective that INACH has systematically addressed. The Antarctic School Fair for 20 years has led thousands of high school students to ask questions about Antarctica and to seek science-based answers with the help of their teachers.

According to Oppliger, et al. (2019), "science fairs increase motivation for science, interest in pursuing a scientific career, and decrease perceptions of scientific complexity in high school students, regardless of gender and socioeconomic level." In addition, several pedagogical methodologies state that learning based on experience and project development emotionally engages young people in the learning process and enhances collaboration, critical thinking, and communication (Villanueva, et al. 2022), essential transversal skills for the new generations.

The difference between this Fair and others that exist in the country and the world, besides its theme focused on the White Continent, is that it opens the possibility of two spaces that are inaccessible under normal conditions for a Chilean high school student: The winners have the opportunity to travel to Antarctica and to have a first-hand experience of the scientific work of real researchers.

The international cooperation inherent in Antarctic activity has also been a protagonist in the development of the Fair during its 20 years.

1069

Life in the Afterlife: Exploring Shallow Chemosynthetic Microbial Communities on Whale Carcasses in Admiralty Bay, King George Island.

Rebeca Graciela Matheus Lizárraga, Francielii Vilela Peres, Amanda Gonçalves Bendia, Augusto Miliorini Amendola, Vivian Helena Pellizari

University of São Paulo, São Paulo, Brazil

Abstract

Whale carcasses that reach the seafloor act as energy and carbon reservoirs, constituting hotspots of high microbial diversity. Their decomposition fosters the growth of chemosynthetic microorganisms, which are simultaneously crucial as the foundation of the food web and highly sensitive to environmental factors. Research on these communities is scarce and largely restricted to the deep ocean, which differs markedly from vulnerable shallow and polar regions. Anticipated to exhibit unique characteristics influenced by their environmental contexts, these communities are the focus of this first exploration in the Antarctic region, which aims to characterize the diversity of the biofilm-forming prokaryotic community resulting from a whale-fall experiment. This research is particularly crucial as the Antarctic region faces significant glacier melting, which could impact microbial communities and their ecological roles. Vertebra, intervertebral discs, and knuckle bones samples were fixed in landers, deployed at a 27m depth in Admiralty Bay, King George Island, and 16S rRNA gene was sequenced from the biofilm formed during a year. Different substrates exhibited no significant differences in species richness (Chao1) or diversity (Shannon) indices, but were responsible for microbial community clustering based on Bray-Curtis distance (p=0.03). Vertebral samples were dominated by sulfate-reducing Desulfomonadia (30%) and fermentative Clostridia (14%), while vertebral disc samples showed a prevalence of Gammaproteobacteria (25%) and Bacteroidia (18%), both known for breaking down complex organic compounds. Knuckle bone samples were primarily characterized by Clostridia (38%) and Bacteroidia (26%). Unlike previous whale fall studies in the deep Southwest Atlantic Ocean, which identified sulfate-reducing Deltaproteobacteria and extremophile Epsilonproteobacteria as dominant, our results showed different prevailing microbial groups. This likely reflects not only environmental distinctions between sites but variations in specific anchoring spots. This study sheds light on Antarctic whale fall microbial communities, revealing polar chemosynthetic environment dynamics and guiding future research on their response to environmental changes.

1070

Legal aspects related to harassment and criminal conduct in Antarctica

Dr./ ECR Paola Barros-Delben^1,2,3,4, Dr. Agnieszka Skorupa⁵, Dr. Guilherme Lopes da Cunha⁶, Studant/ ECR Luis Felipe da Silva Mathias¹, Dr. Cláudio Macedo de Souza¹, Dr. Roberto Moraes Cruz¹

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²APECS-Brazil, Belo Horizonte, Brazil. ³South of Brazil University, Palhoça, Brazil. ⁴Polar Sapiens, Florianópolis, Brazil. ⁵University of Silesia, Katowice, Poland. ⁶Escola Superior de Defesa, Brasília, Brazil

Abstract

The risk of harassment increases in polar regions, especially those areas that are considered complex jurisdictional contexts and “lawless land”. The interest in understanding the consequences of harassment in Antarctica and prevention measures motivated Brazil to propose a response protocol and in 2023 an accusation of harassment that occurred in Antarctica was judged and 2 military personnel were condemned. The objective of this work is to describe legal aspects related to the issue of harassment and criminal conduct in Antarctica and future perspectives on risk reduction. Exploratory and prospective study based on interviews and observations recorded in field activities, following 60 to 120 people on five missions to Antarctica (2014-2018), added to an online retrospective survey (n=14), and legal analysis about specificities of countries with Antarctica operations. Combating harassment in polar regions, especially in Antarctica, is faced with restrictions on legal action against harmful conduct, however, it is an important discussion theme, especially since 2019. The underreporting of victims, especially women, is notorious. Men are also subject to harassment in Antarctica, and violence is intensified by: the perception of impunity, high availability of alcohol and substance abuse, absence or insufficient training in interpersonal skills, and encouragement of reporting, fear, and shame. Initiatives to prevent moral harassment in polar regions are growing and the proposed guidelines show promise in raising awareness of behaviors and their repercussions, highlighting different conceptions about violence in Brazil, Poland and in comparison with other countries in America and Europe, both in terms of psychological outcomes for victims, as legal and legal as possible.

1076

Atmospheric forcings of cold and heat waves registered at Carlini Station in the South Shetlands, Antarctica

MSc. Alfredo J Costa¹, Dr. Gabriel E Silvestri^2,3, Dra. Ana Laura Berman^2,3

¹Instituto Antártico Argentino (IAA/DNA), San Martin, Provincia de Buenos Aires, Argentina. ²Centro de Investigaciones del Mar y la Atmosfera (CIMA/CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina. ³Instituto Franco-Argentino para el Estudio del Clima y sus Impactos (UMI IFAECI/CNRS-CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina

Abstract

This work aims to study the frequency of temperature extremes registered at Carlini Argentine Antarctic Station at 25 de Mayo (King George) island in the South Shetlands, to the northwest of the Antarctic Peninsula (AP) for the period 1994-2023. For this analysis, we consider monthly indices about annual frequency of: (a) extreme (10^th or 90^th percentile) daily minimum (Tmin) and maximum (Tmax) temperature, (b) sequences of at least 3 consecutive days with extreme Tmin or Tmax, and, finally, (c) sequences of at least 3 consecutive days with the joint occurrence of extreme Tmin or Tmax, namely, cold and heat waves. Results show the lack of linear trends in the mentioned indices. Surface meteorological observations, atmospheric reanalysis (NCEP/NCAR and ERA5) and air parcel trajectories from the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT) are used to investigate the drivers for the occurrence of cold and heat waves. The associated large-scale atmospheric circulation patterns evidence a northerly flow during the occurrence of heat waves, some of them amplified by a local foehn effect. On the other hand, a south/southeasterly cold air flow is associated to the occurrence of cold waves with air trajectories coming from Southern AP or the Weddell Sea.

1078

Polar Access Drill Enabling light Logistics Implementation for Exploration and Science (Polar-ADELIES)

Dr Britney Schmidt, Polar ADELIES Team

Cornell University, Ithaca, USA

Abstract

Among the top priorities of the international Antarctic science community is accessing deep ice: grounding zones sensitive to climate change and subglacial lakes where unique and underexplored remote ecosystems thrive. Frontier challenges like these require focused development not always achievable by individual science programs. This is particularly critical in Antarctica since capital to develop community resources is limited and key design choices can place logistical restrictions on future science and resource allocation, leading to growing cost or missed opportunity. Polar-ADELIES is a hot water drill (HWD)concept leveraging heritage designs from the British Antarctic Survey and WISSARD programs to enable smart, deep access drilling to achieve interdisciplinary science. Without infrastructure like Polar-ADELIES, we are at risk that the highest priority work envisioned by the community (e.g., COMNAP ARC) may not be realized. Very few small HWDs and no scalable/deep HWDs exist in the US, putting the science community at risk of a decade or more without access to subglacial environments that represent frontier interdisciplinary science.

Polar-ADELIES would consider flexible power, communications, and other interfaces (for example with winches and terminations) to monitor borehole conditions for drilling and science. The interdisciplinary science goals require a range of in situ and ex situ physical and biogeochemical measurements, some of which could be deployed and monitored through the drilling interface, including: hydrography; direct collection of bulk water (~1-10L at discrete depths, or pumping samples to the surface); in situ water filtration systems to concentrate particulates and cells; and subglacial sediment sampling via wireline coring. Deployment of cameras and autonomous/remotely operated vehicles is a frontier that will be enabled. Developing such a drill along with our international partners would enable the US to contribute cutting edge technological advancements to hot water drilling, helping reduce both cost and risk of drilling operations.

1082

Biogeographical patterns in the genus Laevilitorina (Gastropoda: Laevilitorininae) across its distribution in different provinces of the Southern Ocean

Dr. Claudio González-Wevar^1,2,3, Mg. Sc. Sebastián Rosenfeld², Dr. Claudia Maturana², Dr. Julia Saravia^2,3, Dr. Nicolás Segovia⁴, Dr. Thomas Saucède⁵, Dr. Nerida Wilson⁶, Dr. Paul Brickle⁷, Dr. Hamish Spencer⁸, Dr. Elie Poulin^2,9

¹Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ²Instituto Milenio BASE (Biodiversidad de Ecosistemas Antárticos y Subantárticos, Santiago, Chile. ³Programa Fondap IDEAL, Valdivia, Chile. ⁴Facultad de Ciencias del Mar, Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile, Coquimbo, Chile. ⁵Biogéoscience, Université de Bourgougne, Dijon, France. ⁶University of Western Australia, Perth, Australia. ⁷South Atlantic Environmental Research Institute (SAERI), Port Stanley, Falkland Islands, United Kingdom. ⁸Department of Zoology, University of Otago, Dunedin, New Zealand. ⁹Departamento de Ciencias Ecológicas, Universidad de Chile, Santiago, Chile

Abstract

Antarctic littorinids includes three genera of small nearshore benthic marine gastropods: Laevilitorina, Laevilacunaria and Pellilitorina. The genus Laevilitorina comprises 25 nominal species distributed in southern South America, the Antarctic Peninsula, Australia, New Zealand and sub-Antarctic islands of the Southern Ocean (South Georgia, Marion, Crozet, Kerguelen, Heard, Macquarie, Campbell, Antidodes, Auckland, Bounty). Laevilitorina species exhibit low dispersal potential with benthic protected development and most of them are narrow endemics. In this study we performed multi-locus phylogenetic reconstructions, species delimitation analyses and divergence time estimations in Laevilitorina across its distribution in South America, the Antarctic Peninsula, sub-Antarctic islands of the Southern Ocean and New Zealand. Molecular results recognized at least nine different species within the nominal species L. caliginosa. Contrarily, the Antarctic species L. antarctica, L. claviformis and L. umbilicata are conspecifics. We clearly distinguished evolutionary lineages from different biogeographical provinces analyzed. In southern South America we recognized eight different species of Laevilitorina. Three of them (L. magellanica, L. pepita, L. fueguina) are currently found in the Strait of Magellan, two in Cape Horn (L. caliginosa, L. hicana) and three species (L. latior and two new species) in the Falkland/Malvinas Islands. The species L. venusta expands its distribution between the Antarctic Peninsula and Macquarie Island. Three different species were recorded in New Zealand sub-Antarctic Islands (L. delli, L. bifasciata, L. aucklandica) while a fourth new species was found in New Zealand South Island. Biogeographical patterns reflect the important role of plate tectonic vicariance together with recent long-distance dispersal events. This study represents the most detailed integrative study of Laevilitorina across its distribution in different provinces of the Southern Ocean and reveals an unforeseen diversity across this region.

1088

Detection of anthropogenic noise pollution as a possible chronic stressor in Antarctic Specially Protected Area No. 150, Ardley Island

M.S Maximiliano Anzibar Fialho¹, Dr. Martín Rocamora^2,3, Dr. Lucía Ziegler⁴

¹Instituto de Física, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Instituto de Ingeniería Eléctrica, Facultad de Ingeniería, Universidad de la República, Montevideo, Uruguay. ³Music Technology Group, Universidad Pompeu-Fabra, Barcelona, Spain. ⁴Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional Este, Universidad de la República, Montevideo, Uruguay

Abstract

The worldwide increase in anthropogenic noise due to human expansion and intervention in ecosystems, has generated an increase research regarding the effects of noise on wildlife and the functioning of natural systems. Antarctica, considered an isolated, well preserved environment, is increasingly experiencing the effects of human activities and their impacts. In particular, Fildes Peninsula is a logistic hub acting as a gate to the Antarctic Peninsula. At the same time, it possesses some key wilderness values, so monitoring human activities is particularly important. The use of sound to monitor Antarctic environments has almost been limited to marine ecosystems, mainly for studying the influence of ship traffic or underwater construction. However, research on the effects of anthropogenic noise in terrestrial environments has lagged behind.

In this work, we aimed to study the incidence of a specific anthropogenic noise source on Ardley Island (ASPA 150). By analyzing recordings from continuous sound monitoring devices, we quantified the presence of the noise of a power generator in the ASPA soundscape, and developed a simple detection algorithm that enables us to rapidly identify recordings with significant levels of noise from the source. By cross-validating it with meteorological and perceptual data (PCC = 0.63±0.12) we found that, with certain wind conditions, the power generator is clearly audible from the ASPA (Fig. 1) which could potentially represent a harmful impact to wildlife. These results must raise awareness on the possible impacts on the local fauna, since it's already documented that species found in these regions are behavioral modulated by noise. We consider this kind of study should be considered for a proper management of ecological stressors in the ASPA.

1091

Latitudinal Gradients and Vertical Connectivity in the Scotia Sea Microbiome

Dr. Mireia Mestre^1,2,3, Dr. Camila Fernández^3,4,5, Dr. Beatriz Diez⁶, Dr. Jesse McNichol^7,8, Dr. Jed Fuhrman⁷, Dr. Ramiro Logares⁹, Dr. Bjørn A. Krafft¹⁰, Dr. Juan Höfer¹¹

¹National Museum of Natural Sciences (MNCN-CSIC), Madrid, Spain. ²IDEAL Center, Austral University from Chile (UACh), Valdivia, Chile. ³COPAS-Coastal Center, University of Concepción (UdeC), Concepción, Chile. ⁴University of Concepción (UdeC), Concepción, Chile. ⁵Laboratory of Microbial Oceanography, CNRS UMR7621, Banyuls sur Mer, France. ⁶Pontifical Catholic University of Chile (PUC), Santiago, Chile. ⁷University of Southern California (USC), Los Ángeles, USA. ⁸Saint Francis Xavier University (StFX), Antigonish, Canada. ⁹Institute of Marine Sciences, Barcelona, Spain. ¹⁰Institute of Marine Research (IMR), Bergen, Norway. ¹¹Pontifical Catholic University of Valparaíso (PUCV), Valparaíso, Chile

Abstract

Little is known about the species diversity of microscopic plankton and their distribution patterns within the Southern Ocean. In this study, we conducted a latitudinal transect in the Scotia Sea, from the South Georgia Islands (North) to the South Orkney Islands (South), including eight oceanographic stations. At each station, seawater samples were taken at depths from the surface to 1000 m and were fractionated by size (0.2-3.0; 3-20; 20-200 µm). Subsequently, the diversity of prokaryotes (including Bacteria and Archaea) and unicellular eukaryotes in each sample was determined by metabarcoding. The primary objective was to describe how microbial diversity changes latitudinally and throughout the water column. The results showed that the abundance of prokaryotes decreased from north to south, whereas that of eukaryotes increased. Only a small percentage of the surface microbial species reached the deep ocean (<13% of the species and <25% of the sequences). A drastic decrease in microbial vertical connectivity, together with strong changes in community composition, was detected during the transition from epipelagic to mesopelagic waters (100-200 m). We also found that the vertical connectivity decreased gradually from the northern to southern latitudes. In summary, the Scotia Sea is characterized by a low microbial connection along the water column, which in turn may indicate a low vertical transport of particles

1092

Progress and future plan of Chinese scientific drilling in Antarctica

Professor Youhong Sun

China University of Geosciences, Beijing, Beijing, China

Abstract

Scientific drilling in Antarctica is the only one method for obtaining samples from glacial ice and subglacial environments and deploying scientific observation instruments in ice and subglacial environments. China has developed the shallow ice core drills since the late 1980s. After more than 30 years of development, polar scientific drilling technology in China has made significant progress. The armored cable type deep ice core drill jointly developed with Japan has been successfully applied in the Dome A deep ice core scientific drilling project, and currently the borehole reached the depth of 803 m. The Antarctic subglacial drilling rig has completed trial drilling and application in the Dalk Glacier, Antarctica. In the 2023/2024 Antarctic season, 545 m ice cores and 0.48 m subglacial bedrock cores were successfully recovered. The original Antarctic subglacial lake recoverable autonomous sonde was developed to obtain environmental-friendly subglacial lakes samples. In the 2021/2022 Antarctic season, the field drilling test of this system was completed at the Dalk Glacier, Antarctica, with a total penetration of 517 m drilled down and returned back to the ice surface. The report also presents recent progress of Antarctic Qilin Subglacial Lake Scientific Drilling Project, the future planned Antarctic Gamburtsev Subglacial Mountain Scientific Drilling Project, and the discussion of the feasibility of restarting the Dome A deep ice core scientific drilling project.

1093

What’s fun got to do with it? Engaging the public in Antarctic Science

Hayley Kwasniewski, Rose Leeger, Ivory Carpenter, Dr. Cassandra Brooks

University of Colorado, Boulder, USA

Abstract

From harboring critically important species to regulating the climate of our planet, Antarctica is foundational to life on Earth. However, there is a disconnect between Antarctica and everyday life. Perhaps due to Antarctica’s remote nature and an understandable “out-of-sight, out-of-mind” bias, it is difficult for scientists to communicate how important this region is to global well-being. The need for public awareness feels even more pressing as anthropogenic activities severely impact global ecosystems, especially the particularly sensitive Antarctic region. Research has shown that sharing dire information can lead to climate fatigue and distress, which have the potential to hinder actionable steps. How can Antarctic scientists inspire the public to care about the continent without instilling debilitating fear or anxiety? Here, we share several examples of public engagement that focus on the fun, awe-inspiring aspects of Antarctica, and share insights into how we present Antarctic research. Engagements include family events, public talks, youth science competitions, and out-of-the-box social media strategies delivered to audiences of U.S. elementary school students and families, middle and high schoolers, college students, adults, and senior citizens. We will present metrics on engagement activities, such as number of participants, interactions on social media, post-event follow-ups, observations, and anecdotal experiences. While we acknowledge we have not reached a global audience, we hope that our insights are adaptable elsewhere and for other audiences. Foundationally, we find that targeting our stories to the audience, leaning into the magic of Antarctica, and inspiring others to get outside their comfort zones, especially early career scientists, aids in the creation of deep learning and engagement, leaving the audience more aware and appreciative of Antarctica’s ecological and climatological significance.

1094

Unraveling Unexpected Solar Wind-Magnetosphere-Ionosphere Coupling: A Case Study of Extreme Subauroral Ion Drifts during quiet geomagnetic conditions

Bea Gallardo-Lacourt^1,2, Yukitoshi Nishimura³, Larry Kepko¹, Emma Spanswick⁴, Eric Donovan⁴, D. Megan Gillies⁴, David Knudsen⁴, Jonathan Burchill⁴, Victor Pinto⁵, Jeremy Kuzub⁶

¹NASA/GSFC, Greenbelt, MD, USA. ²CUA, Washington DC, USA. ³Boston University, Boston, USA. ⁴University of Calgary, Calgary, Canada. ⁵Universidad de Santiago, Santiago, Chile. ⁶Jufa Intermedia, Halifax, Canada

Abstract

Unprecedentedly quiet geomagnetic conditions, colloquially referred to as 'The Day the Solar Wind Disappears,' have been observed in the past, offering valuable insights into how the magnetosphere and ionosphere respond to minimal driving forces. These episodes have been instructive in understanding the dynamics of these critical Earth-space interactions.

In recent years, heightened interest has emerged in investigating extreme electric fields and flows within the subauroral ionosphere, spurred by the discovery of a unique optical phenomenon in the night sky named STEVE (Strong Thermal Emission Velocity Enhancement). Although sharing visual similarities with auroral emissions, STEVE possesses distinctive characteristics. Traditionally associated with active conditions and prolonged substorm expansion phases, existing literature posits that substorms play a pivotal role in creating the conditions conducive to subauroral ion drifts and flow enhancements.

This presentation unveils an unexpected observation: a specific STEVE event characterized by extreme subauroral ion drift conditions, occurring independently of a substorm, during periods akin to "when the solar wind disappears." This case study poses new questions into the drivers of subauroral dynamics and the impact of solar wind-magnetosphere coupling on ionospheric responses.

1095

Evidence of trans-APF long-distance dispersal in a nearshore marine invertebrate in the Southern Ocean

Dr. Claudio González-Wevar^1,2,3, Dr. Julia Saravia^2,3, Dr. Valentina Bernal², Dr. Nicolás Segovia⁴, Dr. Sebastián Rosenfeld², Dr. Claudia Maturana², Dr. Thomas Saucède⁵, Dr. Paul Brickle⁶, Dr. Hamish Spencer⁷, Dr. Elie Poulin^2,8

¹Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ²Instituto Milenio BASE (Biodiversidad de Ecosistemas Antárticos y Subantárticos), Santiago, Chile. ³Centro Fondap IDEAL, Valdivia, Chile. ⁴Facultad de Ciencias del Mar, Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile, Coquimbo, Chile. ⁵Biogéoscience, Université de Bourgougne, Dijon, France. ⁶South Atlantic Environmental Research Institute (SAERI), Port Stanley, Falkland Islands, United Kingdom. ⁷Department of Zoology, University of Otago, Dunedin, New Zealand. ⁸Departamento de Ciencias Ecológicas, Universidad de Chile, Santiago, Chile

Abstract

Long-distance dispersal (LDD) represents a main biogeographic mechanism in the Southern Ocean. Several groups of marine invertebrates exhibit evidence of LDD but most of the examples have been recorded around the Antarctic continent and among sub-Antarctic provinces. Although occasional LDD occurred over long (evolutionary) timescales across the Antarctic Polar Front, there is little evidence of ongoing gene flow across this barrier. Molecular studies suggest that there is almost no evidence of successful biological dispersal into the Antarctic from lower latitudes and vice versa. In a recent study conducted in the littorinid genus Laevilitorina, the species L. venusta showed a broad distribution in Antarctic and sub-Antarctic provinces. Species of Laevilitorina are very abundant in rocky bottom ecosystems and exhibit benthic protected development without free-living larval stages. Here, we performed population-based molecular analyses including more than 586 individuals from 17 localities across the species’ distribution. In general, L. venustashowed medium levels of genetic diversity with a short genealogy and several dominant haplotypes. General patterns of population structure showed the presence of six different genetic groups: 1) maritime Antarctic including Signy Island; 2) South Georgia; 3) Marion; 4) Crozet; 5) Kerguelen and 6) Macquarie Island. Interestingly, each of the sub-Antarctic islands here analyzed represents a different genetic group. Moreover, we found evidence of bi-directional and asymmetrical gene flow in L. venusta between Antarctic and sub-Antarctic provinces. This Laevilitorina species represents one of the first confirmed example of a near-shore marine benthic invertebrate found in both Antarctic and geographically distant sub-Antarctic ecosystems. Considering the reproductive mode in Laevilitorina LDD mediated by rafting seems to represent a key mechanism in L. venusta.

1097

Antarctic nematode genetic structure reflects historical climate disturbances and geomorphic barriers

Abigal Jackson¹, Steven Leavitt¹, Dorota Porazinska², Diana Wall³, Thomas Powers⁴, Timothy Harris⁵, Byron Adams¹

¹Brigham Young University, Provo, USA. ²University of Florida, Gainesville, USA. ³Colorado State University, Fort Collins, USA. ⁴Universithy of Nebraska, Lincoln, USA. ⁵University of Nebraska, Lincoln, USA

Abstract

Historical climate disturbances, such as glacial cycling and fluctuating stream, lake, and sea levels, have a profound influence on the distribution and evolutionary trajectories of Antarctic terrestrial species. Antarctic invertebrates, including the ubiquitous sentinel nematode species Scottnema lindsayae, are particularly sensitive to climate disturbances. We tested hypotheses associated with the historical geographic and population genetic structure of this species as it occurs across the McMurdo Dry Valleys (MDVs) of Antarctica. To reconstruct the influence of climate disturbance and ecological conditions on this species, partial mitochondrial cytochrome c oxidase I (COI) gene sequences were sequenced and analyzed from individual S. lindsayae collected from sites across the MDVs reflecting opposing gradients of climate disturbance during the Last Glacial Maximum (LGM). We found that populations were strongly demarcated by geomorphic barriers, with distinct haplotypes associated with valleys except among valleys that experienced glacial advance and retreat during the LGM. Our work shows that contemporary populations of these animals are strongly structured by prior climate history and reinforced by subsequent ecological conditions. Such findings can be useful for understanding the processes that shape the distribution and abundance of these ecologically important animals and interpreting long-term monitoring of demographic shifts in response to changing climate trends in the McMurdo Dry Valleys.

1098

Revisit Gamburtsev subglacial mountains in East Antarctica: a new perspective for machine learning-based automatic prediction of subglacial water bodies

Prof. Tong Hao, Miss Qian Ma, Miss Chen Lv

Tongji University, Shanghai, China

Abstract

Over ten years ago, the Gamburtsev subglacial mountains (GSMs) in East Antarctica were under the spotlight of worldwide glaciologists after the AGAP project was conducted. With the dense grid of radar echo sounding (RES) survey data, various groups have claimed a massive number of subglacial water bodies (SWBs) exist within the valleys of the mountains. However, they were identified by manually evaluating the reflectivity anomalies, which inevitably introduced subjective errors. With the fast development of machine learning (ML) technologies, researchers have started to use such data-driven methods to reevaluate the accuracy of manual labelling of SWBs. However, these types of automatic methods are always facing the issue of data imbalance, which means that the number of training samples in each class is unequal or with tremendous differences. This is particularly the case for SWBs prediction since they normally occupy a rather small fraction of the basal topography, and it can often lead to an ill prediction if the training is not properly defined. In this study, we propose a novel ML method that combines the Artificial Bee Colony (ABC) optimization algorithm with a stacking ensemble model to automatically predict SWBs in the GSMs. Our method first extracts and utilizes several key features from RES data, and then the ABC algorithm selects the optimum ensemble learning model, as well as the most suitable base learner and meta-learner for the following stacking fusion, which is then utilized for SWBs prediction. Experimental results successfully demonstrate its superiority over previous approaches, mitigating the common parameter threshold dependence and achieving high prediction accuracy despite the severe imbalance issue of RES data. Furthermore, this study presents an inventory of subglacial lake candidates across the GSMs, with a total of 72 new subglacial lake candidates with lengths ranging from 308 m to 31,376 m having been predicted.

1099

The untapped potential of crowdsourcing to support research in the polar regions: assessing the impact of citizen science on tourist vessels.

Verena Meraldi¹, Emily Baxter¹, Tudor Morgan¹, Elizabeth Leane²

¹HX | Hurtigruten Expeditions, London, United Kingdom. ²University of Tasmania, Hobart, Australia

Abstract

Citizen science’s (CS) popularity and use in scientific research has increased over recent years. Literature reports that CS can promote positive change; enhance public knowledge, understanding, and awareness of environmental issues; and amplify conservation efforts.

Accessibility to polar regions is limited and expensive. CS monitoring is an important cost-effective alternative to conventional programs where funding and infrastructure are unavailable, allowing for greater spatial and/or temporal coverage, including geographical areas that remain under-researched. With resources from other traditional platforms (i.e. research vessels and funding) decreasing, research institutions are capitalizing on private sector tourism as a ‘crowdsourcing’ data collection alternative, with the added benefit of passenger participation and education.

HX’s Science & Education Program focuses on broadening guests’ understanding of the Antarctic and Southern Oceans ecosystems and climate change impacts. On our voyages, tourists become active participants in data collection through an immersive educational onboard program and on-site interaction with researchers. During the 2023-24 season we allocated over 1600 cruise nights and welcomed 80+ researchers from collaborating institutions on our vessels. Guests contributed more than 23,000 data submissions to over 20 different CS projects globally in 2023. However, HX represents approximately 8% of the polar expedition cruising industry. The full potential for future partnerships to tap into these vast resources as an industry is yet to be realized.

To better understand this potential and to evaluate the longer-term effect of participation in CS on guests, HX carried out a research project in partnership with UTAS during 2022 and 2023. While analysis is still ongoing, preliminary results from semi-structured interviews with over 70 guests on three HX vessels suggest that guests saw CS activities, and the Science & Education program more generally, as a core part of their experience, and many returned with a heightened sense of the fragility of the region.

1100

Exploring the Future of Coastal Antarctic Snow Algae in a Warming Climate

Associate Professor Alia Khan¹, MS Student Colby Rand¹, Professor Raul Cordero², Senior Scientist Ted Scambos³, Professor Heidi Dierssen⁴, Post-Bac Student Molly Adshead¹

¹Western Washington University, Bellingham, USA. ²Universidad De Santiago de Chile, Santiago, Chile. ³University of Colorado - Boulder, Boulder, USA. ⁴University of Connecticutt, Groton, USA

Abstract

Rapid and persistent climate warming in the Western Antarctic Peninsula is likely resulting in intensified snow-algae growth and an extended bloom season in coastal areas. The presence of snow algae blooms enhance the absorption of solar radiation by snow and ice surfaces. This positive feedback creates a measurable radiative forcing, which can have immediate local and long-term regional impacts on albedo, snow melt and downstream ecosystems. This 5-year project is investigating the spatial and temporal distribution of snow algae, black carbon and dust across the Western Antarctica Peninsula region, their response to climate warming, and their role in regional snow and ice melt. Data is being collected across multiple spatial scales from in situ field measurements and sample collection to high resolution multi-spectral satellite imagery. Ground measurements are informing development and application of novel algorithms to map algal bloom extent through time using 0.5-3m spatial resolution multi-spectral satellite and 1 - 3 cm UAV imagery. These time-series data then inform bio-albedo feedbacks, which are used to calculate instantaneous and interannual radiative forcing calculations to assess impacts of snow algae on regional snow melt. Quantifying the spatiotemporal growing season of snow algae will increase our ability to model their impact on snow melt, regional climate warming and ice-free expansion in the Antarctic Peninsula region.

1101

Ice shelf rifts: A multi-decade record of propagation and topographic change at the feature scale

Dr. Catherine Walker¹, Dr. Brad Lipovsky², Mr. Chancelor Roberts³, Ms. Caroline Needell⁴, Dr. Helen Fricker³, Dr. Ashley Morris²

¹Woods Hole Oceanographic Institution, Woods Hole, MA, USA. ²University of Washington, Seattle, WA, USA. ³UCSD Scripps Institution of Oceanography, La Jolla, CA, USA. ⁴Massachusetts Institute of Technology, Cambridge, MA, USA

Abstract

Ice shelf rifts are the precursors to iceberg calving, one of the main mechanisms of mass loss from the Antarctic Ice Sheet. Ice shelf retreat, and in some cases total collapse, is inherently tied to accelerated ice shelf rift propagation. Rift propagation in and of itself is a complex process, and it is not clear yet what the drivers of the rift evolution lifecycle are. Rifts can be monitored over long (months to decades) timescales to better understand the forces controlling iceberg calving. An existing catalog of Antarctic-wide ice shelf rift propagation behavior, published in 2013, contains one decade (2002-2012) of data based on medium-resolution (250 m), daylight-only imagery from two sensors. The ever-increasing satellite record is now long enough to develop a set of multi-decadal observations of ice shelf rifts. Here, we present multi-sensor observations of the propagation activity and related 3D morphology evolution of ice shelf rifts over their lifecycle. This updated catalog is enabled both by enhanced visible imagery resolution (~1-30 m, Worldview, Sentinel, and Landsat imagery) across multiple missions to facilitate better revisit times and higher temporal coverage (daily to bi-weekly vs. seasonal), including over the wintertime, in addition to topographic information over active and dormant rifts from the ICESat and ICESat-2 laser altimeters. Our updated ice shelf rift observation catalog enables a holistic analysis of ice shelf rifts on the Antarctic-wide scale over a period of at least two+ decades (2000-2023), and in some places, up to 50 years using the Landsat archive. This updated catalog of rift activity will help to study the ice shelf rift lifecycle and how those relate to environmental changes over time. This product also enables the ability to compare future changes in ice shelf rifting and thereby quantify the effects of external climate forcings on ice shelf retreat.

1103

Development of a laboratory simulation for freeze-thaw of aeolian sediments in glacial systems

Denise Mondragon¹, Dr. Ruth Heindel², Dr. Susan Welch³, Dr. Anna Bergstrom⁴, Dr. Melisa Diaz^3,1

¹Department of Geography, University of Colorado, Boulder, Boulder, USA. ²Environmental Studies Department, Kenyon College, Gambier, USA. ³School of Earth Sciences, The Ohio State University, Columbus, USA. ⁴Department of Geoscience, Boise State University, Boise, USA

Abstract

Glacial systems are vital for supplying trace metals, nutrients, and weathering products to proglacial and marine ecosystems. While previous research has largely focused on subglacial and proglacial systems, less attention has been given to weathering processes in the most upstream sources: snow and supraglacial ice. Aeolian sediments on glaciers and snowbanks have a lower albedo than snow and can generate meltwater under high solar irradiance. However, meltwater can refreeze around sediment grains during cloudy days, obstructed sunlight, or when the sun sets, resulting in a freeze-thaw process. It remains unclear whether chemical or physical weathering dominates in releasing nutrients for downstream ecosystems during this process.

This study presents a robust methodology to simulate freeze-thaw processes in natural glacial environments, involving initial wetting followed by multiple freeze-thaw cycles. Aeolian sediments from Antarctica's McMurdo Dry Valleys were used for validation. Analysis revealed significant differences in major ion, nutrient, and metal concentrations between initial wetting and specific freeze-thaw cycles (1, 5, 10, 30, 60). For instance, phosphorus concentrations consistently increased with each cycle, particularly evident in samples from Explorer’s Cove, which is composed of younger and mafic tills. Similarly, silica exhibited an increase from cycle 1-30 but decreased at cycle 60. In contrast, nitrate + nitrite displayed a unique trend, decreasing or remaining relatively stable in subsequent cycles before rising again in cycle 60 for some sites. Additionally, iron concentrations were significantly higher during the initial leach at each site and remained less than 0.01µmol/g during each cycle after that.

This research underscores the significance of freeze-thaw processes in understanding physical weathering dynamics in glacial environments, especially regarding nutrient release mechanisms for downstream ecosystems. The methodology marks the beginning of many future studies on freeze-thaw weathering, offering the potential for deeper insights into how chemical and physical processes shape glacial environments.

1107

Diseñar en blanco. A collective approach to Architecture and Dwelling in Antarctica.

Dr Victoria Nuviala Antelo^1,2, Architect Violeta Nuviala Antelo¹

¹Universidad de Buenos Aires, Buenos Aires, Argentina. ²Casa de Velázquez & MIAS, Madrid, Spain

Abstract

Since 2019, the interdisciplinary research team 6044SUR has devoted its efforts to the design and construction of Archive SUR, a collaborative virtual platform dedicated to the study of Architecture, Dwelling and Habitat in Antarctica. This platform aims not only to promote research in the field of Antarctic architecture, but also to shed light on everyday life in Antarctica through the multiple experiences of different people who have travelled to Antarctica as part of scientific, logistic, and commercial activities.

As part of this collaborative platform, the research team has developed a series of engagement activities with Argentine universities. The first of these activities was an internship programme “Mapping Architecture” developed jointly with the University of Buenos Aires, where advanced undergraduate students were invited to contribute to the production of the Antarctic Architecture Catalogue. The programme consisted of 10 virtual encounters that took place during the semester. While three of these meetings were dictated by specialists from around the world in a wide range of polar disciplines, the rest of the meetings were dedicated to sharing progress, doubts, and debates about the research process on Antarctic architecture. The second activity was a Workshop dedicated to the design of Antarctic architecture, called "Diseñar en Blanco", where students and early career architects were invited to design their own scientific facility. This workshop was developed as part of the SCAR Fellowship "Mapping Memories..." and took place at the University of Buenos Aires, where a total of 30 students participated in micro-conferences and a design workshop.

The aim of this presentation is to present the progress made within the Intern Research Program “Mapping Architecture” and the architectural projects produced during the Design Workshop “Diseñar en blanco”, with the intention of exploring potential future lines of engagement with Latin American Universities.

1110

Long-Term Monitoring of Antarctic Benthos through Photogrammetry: Automated Organism recognition and Library Development

Ms. Alice Guzzi^1,2, Dr. Massimiliano Corsini³, Dr. Fabio Menna⁴, Dr. Erica Nocerino⁵, Dr. Fabio Remondino⁴, Ms. Asia Mantovan¹, Mr. Daniel De Alexandris¹, Dr. Stefano Schiaparelli^1,2, Dr Gaia Pavoni⁶

¹Department of Earth, Environmental and Life Sciences (DISTAV) - University of Genoa, Genoa, Italy. ²Italian National Antarctic Museum (MNA, section of Genoa), Genoa, Italy. ³Visual Computing Lab ISTI-CNR, Pisa, Italy. ⁴3D Optical Metrology (3DOM) Unit, Bruno Kessler Foundation (FBK), Trento, Italy. ⁵Department of Humanities and Social Sciences - University of Sassari, Sassari, Italy. ⁶Institute of Information Science and Technologies "Alessandro Faedo" - CNR Research Area of Pisa, Pisa, Italy

Abstract

Antarctic benthic ecosystems support a unique fauna characterized by high levels of diversity and endemism. Despite their ecological significance, these communities remain relatively understudied, and essential aspects of their ecology, such as spatial variability, remain poorly understood. The challenging combination of remoteness and harsh environmental conditions further complicates our understanding of these unique ecosystems.

The lack of time-series information hinders our understanding of temporal variation in ecological communities, emphasizing the need for baseline data for detecting natural or anthropogenic changes. However, conducting long-term monitoring in polar regions is logistically demanding and costly. Recent technological advancements have enabled non-destructive methodologies for studying benthic dynamics and spatial patterns. These include improved underwater optical recording systems, optimization of image sampling and mapping techniques for 3D reconstructions, and development of software for benthic imagery analysis. Photographic or video sampling allows permanent records for comprehensive image analyses, reducing underwater time and expertise needed for species identification.

The primary aim of this research is to establish a comprehensive library of Antarctic benthic organisms using photogrammetry software, thereby expediting identification and reducing manual classification efforts. By integrating photogrammetry and automated organism recognition, this study aims to develop a sustainable long-term monitoring system for Antarctic benthic ecosystems. This approach has the potential to enhance our understanding of dynamic changes in these ecosystems over time, facilitating informed conservation and management strategies in response to environmental challenges.

1111

Life history of Antarctic toothfish in the Ross Sea: implications for fish ecology and fisheries

Hayley Kwasniewski¹, Rose Leeger¹, Clare Gallagher¹, Dr. Ashley McKenzie¹, Dr. Jennifer Devine², Dr. César Cárdenas³, Francisco Santa Cruz³, Dr. Arthur Devries⁴, Dale Maschette^5,6, Dr. Cassandra Brooks¹

¹University of Colorado, Boulder, USA. ²NIWA (National Institute of Water and Atmospheric Research Ltd), Port Nelson, New Zealand. ³Instituto Antarctico Chileno (INACH), Punta Arenas, Chile. ⁴University of Illinois, Champaign, USA. ⁵University of Tasmania, Hobart, Australia. ⁶IMAS (Institute for Marine and Antarctic Studies), Kingston, Australia

Abstract

Accurate life history information, including age and growth, is a necessary component of sustainable fisheries management. Commercial fishing for Antarctic toothfish, Dissostichus mawsoni (the top fish predator in the Southern Ocean), in the Ross Sea commenced in 1997, under the management of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Currently up to 12 member countries fish in the Ross Sea each austral summer, collectively removing roughly 3000 tonnes annually, although catch limits have varied over time. Previous studies suggest that these bentho-pelagic fish have long lifespans (~40 years) with relatively slow growth rates and inhabit waters down to over 2000 meters. Notably, fishing can change life history parameters of fished species, including age and size at maturation. Using a time series for Antarctic toothfish in the Ross Sea (2,000+ samples from 1980-2023), we investigate the toothfish’s life history parameters during this period. This study uses otoliths, calcium carbonate “ear stones” that, similar to tree trunk rings, deposit annual layers over the course of a fish’s life. Fish ages were estimated by sectioning and reading the otoliths using established protocols for toothfish. Age and growth parameters were calculated using a von Bertalanffy growth function, including growth rates and longevity. We then tested for statistically significant differences in parameters. Changes in life history over time will be presented, revealing insights into life history and population dynamics for Antarctic toothfish in the Ross Sea region. Plans for further life history connectivity work is discussed, including age and growth parameters for fish caught by fishing vessels in other regions of the Southern Ocean. In addition to age and growth, we will present on future work involving the chemical analysis of otoliths to evaluate life history connectivity hypotheses for Antarctic toothfish.

1112

PRESERVING ANTARCTICA FOR PLANETARY SUSTAINABILITY: THE IMPACT OF GELO NA BAGAGEM INSTITUTE

Francyne Elias-Piera

Instituto Gelo na Bagagem, São Paulo, Brazil

Abstract

The “Gelo na Bagagem” (Ice in the Luggage) Institute emerged in 2019 as an Antarctic education and entertainment platform, aiming to disseminate knowledge about polar science in an accessible and enjoyable manner. Over time, it has expanded its reach, impacting more than 10,000 individuals and creating a community engaged in environmental issues and aware of the relevance of preserving Antarctica for the survival of humanity and the planet. Gradually, the Institute evolved into a non-governmental organization with well-defined purposes: biodiversity conservation, awareness of climate change, promotion of scientific research, and advocacy for environmental protection. Through courses, lectures, and audiovisual resources shared on platforms like YouTube and Instagram, the organization has reached diverse audiences of different ages and genders, contributing to increased environmental awareness. The Institute's innovative methodological approach, based on videos, live broadcasts, and social media posts, has proven effective in engaging the public and teaching about Antarctica. Moreover, the initiative has had positive impacts on formal education, with teachers incorporating the content into their classrooms and students showing greater interest and improved academic performance. “Gelo na Bagagem” has also contributed to the training of new researchers and scientists, providing internships and opportunities for students interested in studying Antarctica. On the global stage, the organization acts as an advocate for Antarctica preservation, promoting marine protected areas, and pressing for responsible environmental policies. Raising awareness of Antarctica's importance and the impact of climate change is crucial for developing a comprehensive vision of sustainability. The success of the “Gelo na Bagagem” Institute underscores the importance of educational programs and media initiatives to disseminate knowledge about environmental issues and engage society in sustainable actions. Preserving Antarctica emerges as a global priority, and the Institute plays an active role in defending this unique ecosystem vital for planetary sustainability.

1114

Analysis of the structure and dynamics of pioneer benthic communities in Terra Nova Bay (Ross Sea, Antarctica) using the Autonomous Reef Monitoring Structures (ARMS)

Ms. Valentina Cometti^1,2, Dr. Matteo Cecchetto^2,3, Dr. Stefano Schiaparelli^2,3

¹University of Siena, Siena, Italy. ²Italian National Antarctic Museum (MNA), Genoa, Italy. ³University of Genoa, Genoa, Italy

Abstract

The Southern Ocean has unique environmental conditions compared to other areas of the world, making it a key area for the analysis of future biodiversity changes. The peculiarities of this polar ecosystem have played an important role in structuring marine biodiversity, being characterized by high levels of endemism, ecological and cryptic diversity. Overall, available data on the development and dynamics of benthic communities have shown a marked sensitivity to anthropogenic and climatic changes, indicating a profound impact at both the community and species levels. However, these studies have rarely been conducted with reproducible and standardised techniques, limiting our understanding of these changes in both space and time. Here, we present the application of Autonomous Reef Monitoring Structures (ARMS) to study pioneer benthic communities’ development. Each ARMS consists of 10 stacked PVC plates with a 1 cm space to allow colonization on both surfaces. These structures are characterized by a simplified design, allowing researchers to use more advanced technologies, such as High Throughput Sequencing and photo-analysis to study of colonising organisms. The ARMS were deployed at 25 metres of depth near the Italian research station Mario Zucchelli in Terra Nova Bay (Ross Sea) and recovered after 1, 2, 3 and 5 years, respectively. The panels were disassembled, photographed, and the species identified to the lowest taxonomic level possible. Each photograph was analysed using photo analysis software, highlight differences in community composition and structure between increasing years of deployment. These structures represent the first of their kind to be deployed in Antarctica, providing a fundamental tool for the study of benthic communities, and establishing a baseline against which future population dynamics can be compared.

1121

Development of a miniaturized software-defined ice-penetrating radar system for UAV-borne deployment

Thomas Teisberg¹, Dr. Dustin Schroeder¹, Dr. Jamin Greenbaum²

¹Stanford University, Stanford, CA, USA. ²Scripps Institute of Oceanography, La Jolla, CA, USA

Abstract

Ice-penetrating radar is among the most scalable instruments for collecting sub-surface measurements, including bed topography, basal reflectivity, englacial stratigraphy, and other englacial properties. Unfortunately, collecting IPR data from crewed airborne platforms is expensive and logistically challenging. Uncrewed aerial vehicles (UAVs) are emerging as promising low-cost tools for collecting airborne geophysical measurements. Beyond simply reducing cost, UAV-borne sensors may be deployed with minimal logistical overhead, allowing field teams to respond to changing conditions with targeted measurements, and are well-suited to automated repeat flights to collect time-series measurements.

Quadcopter-borne impulsive radar systems are proving to be valuable tools for logistics and scientific uses on mountain glaciers. Polar ice sheets, where higher bandwidth measurements are desired to better image englacial layers and deeper penetration is required, present new challenges for UAV-borne IPR instruments. Additionally, the larger spatial scale of the Antarctic Ice Sheet makes longer-range fixed-wing UAV systems particularly compelling.

We present insights and data from the development and testing of a miniaturized chirped (coherent) ice-penetrating radar system designed for use with small to medium-size fixed-wing UAVs. The IPR system, built upon flexible open-source code, has been tested on a 2 meter wingspan fixed-wing UAV over two deployments in Greenland and is being designed for use with larger UAVs that can be deployed from icebreakers for investigations of grounding zones around Antarctica.

1126

Physical processes we need to understand to envision responsible sea-level rise interventions

Prof Brent Minchew^1,2, Prof Colin Meyer^3,2

¹Massachusetts Institute of Technology, Cambridge, MA, USA. ²Arête Glacier Initiative, Cambridge, MA, USA. ³Dartmouth College, Hanover, NH, USA

Abstract

The past year has seen a surge in the number of ideas for how we might actively manage Antarctic contributions to sea-level rise. These ideas have received considerable attention in the media, governments, and scientific and philanthropic communities. Naturally, this rapidly evolving discussion has attracted enthusiasm and concern, both of which are important. These reactions highlight the need for a deeper understanding of the relevant physics, ethics, ecology, governance, and more. Here, we focus on some of the physical processes we need to understand to improve projections of sea-level rise and to envision responsible interventions aimed at slowing rates of sea-level rise. We posit that improving projections and understanding the efficacy of intervention are two sides of the same coin, the same questions framed in different ways. Our discussion will focus on the physical processes that allow glaciers to slip rapidly over their beds and help set the sensitivity of the West Antarctic Ice Sheet to warming ocean and atmospheric temperature. We will pay special attention to the deformation of glacier beds and the evolution of subglacial hydrological systems. We will highlight research areas that are primed for development and outline early plans to address these research needs through a new nonprofit, Arête Glacier Initiative.

1130

Tracking Biomass Mobilization in Ice-Covered Antarctic Lakes

Marisol Juarez Rivera¹, Tyler Mackey¹, Dawn Sumner²

¹University of New Mexico, Albuquerque, USA. ²University of California, Davis, Davis, USA

Abstract

Perennially ice-covered lakes in the McMurdo Dry Valleys (MDV) of Antarctica are sources of biomass to the surrounding soils, which are among the most organic poor on earth (0.01 to 0.03 wt% OC). Biomass export in these closed-basin lakes is driven by buoyant remobilization of benthic microbial mats from shallow gas supersaturated zones under the ice cover. Bubbles nucleate on the mats, and with sufficient buoyancy mats float, freeze onto the ice, and are exported through ice ablation. This biomass remains unaccounted for in current organic carbon cycling models for the MDV, which assume net transport from the soils and streams to the lakes. This discrepancy arises because we have few constraints on the mechanism, timing, and rates of biomass export from the lakes. Without these constraints it is difficult to assess the extent of biomass transport or predict how biomass export will respond to climate change. We demonstrate that the depth range supporting mat mobilization (liftoff zone) can expand or shrink over time, leading to potential changes in the mass of exported biomass. During our 2022-2023 field campaign to Lake Fryxell, we documented the thinnest ice-cover on record, and an expanded liftoff zone with a doubling in the surface area with liftoff mat. The liftoff zone expanded into deeper waters, mobilizing a new region of thicker, multi-year growth mats relative to mats within the typical liftoff zone, increasing the amount of mobilized biomass. The δ¹³C of liftoff mats decreases with depth, is distinct from mats growing along the moats and within the streams and could be used to track their surface dispersal. Exceptional years of mat export are hypothesized to have the most significant impact on nutrient export to soil communities; variability in mat liftoff may thus play a role in the MDV ecosystem response to changing climate.

1132

Foregrounding geodiversity in landscape ecology studies: insights from the sub-Antarctic

Dr Daniela Monsanto¹, Prof David Hedding², Ms Sandra Durand², Ms Shilpa Parbhu¹, Mr Matthew Adair¹, Dr Arsalan Emami-Khoyi¹, Prof Peter Teske¹, Prof Peter Convey^3,1, Prof Bettine Jansen van Vuuren¹

¹University of Johannesburg, Johannesburg, South Africa. ²University of South Africa, Florida, South Africa. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Biodiversity patterns are shaped by the interplay between geodiversity (i.e., geological diversity) and organismal characteristics. Superimposing genetic structure onto landscape heterogeneity (i.e., landscape genetics) can help to disentangle their interactions and better understand population dynamics. Previous studies on the sub-Antarctic Marion Island have highlighted the importance of landscape and climatic barriers in shaping spatial genetic patterns, and the value of these islands as natural laboratories for studying fundamental concepts in biology. Here. we assess the fine-scale spatial genetic structure of the springtail, Cryptopygus antarcticus travei, which is endemic to Marion Island (one of the Prince Edward Archipelago islands) in tandem with high-resolution topographical and geological data. Using a species-specific suite of microsatellite markers and a fine-scale sampling design incorporating landscape complexity, we explore genetic patterns overlaid onto high-resolution digital surface models and surface geology data across two one-kilometre sampling transects. Genetic patterns across the landscape closely track terrain ruggedness data (viewed from the perspective of the study species) in concert with landscape discontinuities and barriers to gene flow identified at a scale of a few meters. Our data confirm that the island’s geodiversity plays an important role in shaping intraspecific patterns of genetic diversity. This study illustrates that fine-scale genetic patterns in soil arthropods are markedly more structured than anticipated, given the homogeneity of the vegetation complexes characteristic of the island at the scale of tens to hundreds of meters. By considering and incorporating the complexity of fine-scale and high-resolution geodiversity into our study, we were able to explain much of the observed spatial genetic patterns. Our results not only foreground geodiversity as a driver of spatial complexity but, more widely, hold implications for the conservation and management of the sub-Antarctic islands.

1136

Evaluating Population and Individual-Level Trophic Ecology in Leopard Seals Over Time

Emily Sperou¹, Dr. Douglas Krause², Dr. Renato Borras-Chavez^1,3, Dr. Patrick Charapata⁴, Dr. Daniel Costa⁵, Dr. Daniel Crocker⁶, Dr. Kerri Smith⁷, Dr. Michael Goebel⁵, Dr. Carolina Bonin Lewallen⁸, Dr. Sarah Kienle¹

¹Department of Biology, Baylor UniversityBaylor University, Waco, USA. ²Antarctic Marine Living Resources Program, Ecosystem Science Division, National Oceanic and Atmospheric Administration (NOAA) Fisheries, La Jolla, USA. ³Center of Applied Ecology and Sustainability (CAPES), Department of Ecology, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile. ⁴Environmental Fisheries Science Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA), Seattle, USA. ⁵Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, USA. ⁶Department of Biology, Sonoma State University, Rohnert Park, USA. ⁷Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, USA. ⁸Department of Marine and Environmental Science, Hampton University, Hampton, USA

Abstract

Leopard seals (Hydrurga leptonyx) are Antarctic apex predators that play important roles in the structure and function of the Southern Ocean food webs. Quantifying intraspecific variability and individual specialization in their resource use is challenging due to the solitary nature of leopard seals and limited available data. We analyzed longitudinal profiles of δ¹³C and δ¹⁵N in leopard seal whiskers, comprising of 2,211 segments from 46 whiskers collected from 34 individual seals. A subset of whiskers (n = 19) were repeat whisker samples from seven seals collected over 2-4 years. Timestamp analysis revealed whiskers contained an average of 99.5 ± 52 days of growth and ranged from 19 to 286 days. At the population level, we found males and females had a low level of overlap in isotopic niche space (15-21%). Isotopic niche variation between sexes was primarily driven by differences in δ¹⁵N (trophic position), with a larger isotopic dietary niche width for females (range: 6.96 - 16.16‰) than males (range: 6.49 – 12.51‰). The between-individual variability in both δ¹⁵N (58%) and δ¹³C (53%) was higher compared to the within-individual variability (42% and 47%, respectively), highlighting substantial overall specialization within the leopard seal population, with most individuals categorized as foraging specialists (57% δ¹⁵N, 58% δ¹³C), followed by intermediates (28% δ¹⁵N, 37% δ¹³C) and generalists (13% δ¹⁵N, 6% δ¹³C). Our analysis of inter-annual variability among our repeat individuals suggests that while certain individuals consistently maintained their dietary isotopic space over time, others exhibited annual changes in their isotopic signatures, including transitions observed from foraging specialists to generalists and conversely. Overall, these findings emphasize the importance of considering changes at the individual-level in foraging ecology of Antarctic apex predators to refine our understanding of their role within Southern Ocean food webs.

1137

Carbon flow web model for the inner and outer Beagle Channel (Sub-Antarctica) during springtime

Dr Tomás Ignacio Marina¹, B.Sc. Iara D. Rodríguez², Dr Dick van Oevelen³, Dr Karline Soetaert³

¹Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina. ²Universidad Nacional de General Sarmiento (UNGS), Los Polvorines, Argentina. ³Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, Netherlands

Abstract

The Beagle Channel (BC) constitutes a unique sub-Antarctic coastal ecosystem connecting the Pacific and Atlantic oceans at the southern tip of South America. It is also considered a spatially variable atmospheric CO2 sink. The presence of sills in the BC originates micro-basins which favour the formation of particular biological niches in terms of nutrients, primary production and planktonic communities. Here we developed a mass-balanced carbon flow model for the pelagic ecosystem of BC for the spring season, focusing on two contrasting sites: the inner and outer channel to the west and east of the Mackinlay Strait, respectively. For this, we used a single model for both study sites since the structure of the pelagic community is similar in both sectors of the BC. In order to reflect the differences among sites, we parameterized the model according to each case, inner and outer, mostly considering empirical data gathered during the binational Argentine-Chilean campaign carried out in 2019. The model comprises ten compartments representing the key components of the pelagic community of the BC (e.g., phytoplankton, microzooplankton (67-200 μm), mesozooplankton (200-20000 μm), ichthyoplankton).

Our results show important quantitative differences in the carbon sources produced within the pelagic ecosystem (autochthonous), such as phytoplankton, and that imported (allochthonous), such as terrestrial input, between the inner and outer BC. Noteworthy, benthic resuspension provides as much carbon as the allochthonous source to the pelagic ecosystem in both sites. Overall, these preliminary results suggest a differential energy flow pattern during spring in the inner and outer BC pelagic ecosystems.

1140

Quantarctica version 4

Dr. Kenichi Matsuoka¹, Mr. Anders Skoglund¹, Dr. Daniela Cajiao², Dr. Alex Fraser³, Dr. Benjamin Hills⁴, Dr. Rachel Leihy^5,6, Prof. Daniela Liggett⁷, Mr. Anirudha Mahagaonkar¹, Mr. Yngve Melvær¹, Dr. Sebastien Moreau¹, Dr. Yoshihiro Nakayama⁸, Prof. Peter Neff⁹, Dr. Brice Noel¹⁰, Dr. Guy Paxman¹¹, Dr. Mattia Poinelli^12,13, Prof. Catherine Ritz¹⁴, Dr. Antonia Ruppel¹⁵, Dr. Mirko Scheinert¹⁶, Dr. Elisa Seyboth¹⁷, Mr. Stein Tronstad¹, Prof. Luke Trusel¹⁸

¹Norwegian Polar Institute, Tromsø, Norway. ²Wageningen University & Research, Wageningen, Netherlands. ³University of Tasmania, Hobart, Australia. ⁴Colorado School of Mines, Golden, USA. ⁵Arthur Rylah Institute for Environmental Research, East Melbourne, Australia. ⁶Securing Antarctica's Environmental Future, Monash University, Clayton, Australia. ⁷University of Canterbury, Christchurch, New Zealand. ⁸Hokkaido University, Sapporo, Japan. ⁹University of Minnesota, Minneapolis, USA. ¹⁰University of Liège, Liège, Belgium. ¹¹Durham University, Durham, United Kingdom. ¹²University of California, Irvine, Irvine, USA. ¹³Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA. ¹⁴Université Grenoble Alpes, Grenoble, France. ¹⁵Federal Institute for Geosciences and Natural Resources, Hannover, Germany. ¹⁶Technical University of Dresden, Dresden, Germany. ¹⁷University of Pretoria, Hatfield, South Africa. ¹⁸Pennsylvania State University, State College, USA

Abstract

While open data is a fundamental principle of SCAR's data policy, and data sharing increasingly becomes a cultural norm in science, significant challenges persist in fully leveraging its potential. To address these challenges within the SCAR community, the Norwegian Polar Institute has maintained Quantarctica (http://www.npolar.no/quantarctica) since 2012. This presentation highlights the new version 4 of Quantarctica, which encompasses scientific data, satellite imagery, topographic data, and base maps covering up to 40S. Scientific datasets are curated by theme editors for broader relevance, empowering users to explore beyond their expertise with confidence. High-resolution imagery and topographic data are processed to maintain integrity while ensuring reasonable file sizes. Simple and detailed basemaps, primarily sourced from the Antarctic Digital Database, offer varying levels of detail. The entire system is self-contained for use in remote environments. We present the new Quantarctica version 4 including the latest datasets, share insights from its development, and discuss the future trajectory of this vital resource.

1141

Understanding the risk of marine invasions in the Sub-Antarctic through vessel biofouling.

Dr Siobhan Vye¹, Sue Gregory², Dr Mark Belchier², Dr Simon Morley², Dr Paul Brickle¹

¹SAERI, Stanley, Falkland Islands (Malvinas). ²Government of South Georgia and the South Sandwich Islands, London, South-Georgia and the South Sandwich Islands

Abstract

Vessel biofouling is one of the leading vectors for marine non-native species introductions. However, the risk of species introductions associated with vessel biofouling is dependent on the level and type of biofouling present, which in turn is influenced by factors including operating profile, voyage history, and maintenance regimes. The maritime area of South Georgia and the South Sandwich Islands (SGSSI) is frequented by a range of vessels including fishing, passenger, expedition and research. To better understand the trends in biofouling on vessels visiting SGSSI, hull surveys were opportunistically completed on a range of vessels that entered the SGSSI maritime zone in 2023/24. Further data on operating profile, voyage history and vessel maintenance were collected through questionnaires. Data informed a basic assessment of risk, helped identify key risk indicators and provided learnings on methodology for monitoring and evaluating biofouling management in challenging remote environments. Furthermore, we analysed global case studies of biofouling management policies to consider the applicability, feasibility and likely effectiveness of different components if implemented in the remote sub-antarctic. In this talk, we present the overarching findings of the project, and discuss some of the challenges & opportunities identified in managing the risk of marine invasions through biofouling in the remote sub-antarctic.

1143

Motivational aspects of wintering in polar stations

MSC Alicja WALOTEK¹, Dr. Agnieszka Skorupa¹, Dr. Paola Barros-Delben^2,3

¹University of Silesia,, Katowice, Poland. ²Federal University of Santa Catarina, Florianópolis, Brazil. ³APECS-Brazil, Belo Horizonte, Brazil

Abstract

This investigation was based on the experience of people from 10 different countries working at polar stations. The common characteristics faced by expeditioners at the stations are exposure to an isolated, confined, and extreme environment (ICE) and challenges and barriers to health, safety, and human performance, leading to questions about the motivation to carry out tasks, especially in the polar winter. The objective of this work was to understand the motivation to complete the mission at a polar station in winter. There were 22 women and 64 men responding. The qualitative study considered the theory of grounded motivation for analyzing responses to the questionnaires. In total, 56 categories were detailed, grouped by 17 main themes. The most frequent categories in participants' responses about motivation were: challenge and adventure (n=36); unique experience (n=16) and work performance (n=15). Differences in consistent responses between explorers from different countries, who have had experience at polar stations in Antarctica and the Arctic, and between military and civilian personnel and men and women, were also discussed. The work aims to understand the motivations for polar work and optimize selection and preparation processes for expeditioners, providing better conditions for their stay, especially in winter.

1144

A new estimate of Antarctic geothermal heat flux heterogeneity derived from aeromagnetic data

Fausto Ferraccioli¹, Jonathan Ford¹, Ben Mather², Egidio Armadillo³, Rene Forsberg⁴, Joerg Ebbing⁵, Karsten Gohl⁶, Graeme Eagles⁶, Chris Green⁷, Javier Fullea⁸, Massimo Verdoya³

¹National Institute of Oceanography and Applied Geophysics-OGS, Trieste, Italy. ²School of Geosciences, University of Sydney, Sydney, Australia. ³DISTAV- Università di Genova, Genova, Italy. ⁴National Space Institute, Technical Institute of Denmark, Lyngby, Denmark. ⁵Christian-Albrechts-Universität Kiel, Kiel, Germany. ⁶Alfred Wegener Institute, Bremerhaven, Germany. ⁷University of Leeds, School Earth and Environment, Leeds, United Kingdom. ⁸Universidad Complutense de Madrid, Madrid, Spain

Abstract

Assessing geothermal heat flux (GHF) heterogeneity is critical, as it influences Antarctic ice sheet flow and subglacial melting patterns and hydrology, and it is related to crustal and lithospheric structure, composition, and heat production. Despite its key importance GHF heterogeneity remains poorly constrained in Antarctica due the paucity of direct measurements and different results arising from different geophysical estimates.

Here we present and analyse a new aeromagnetic anomaly compilation to help re-assess Antarctic GHF heterogeneity. We imaged prominent regions of enhanced GHF along the coast of the Amundsen Sea Embayment, in agreement with independent seismological estimates and distinct thermal anomalies within the West Antarctic Rift System (WARS) beneath the Byrd Subglacial Basin. Linear rift related anomalies are also imaged beneath the Siple Coast ice streams and active subglacial lake districts.

In East Antarctica, our new estimates over the Wilkes Subglacial Basin indicate significantly lower GHF compared to most sectors of the WARS. This suggests that if Mesozoic to Cenozoic extension affected the WSB, it mostly occurred at upper crustal levels rather than the modifying the lithosphere, in general agreement with relatively sparse seismological evidence. An intriguing region of enhanced GHF in Dronning Maud Land could arise from lithospheric thinning, perhaps associated with late-Pan African age delamination processes, or it could reflect thermal anomalies related to passive margin formation during Gondwana break up.

Other GHF anomalies underlie the Dome C and Dome A subglacial lake regions. These could relate to anomalously high intracrustal heat production within the Precambrian basement and/or to ill-constrained reactivation of the structural architecture within the basement.

1152

Characterising Von Kármán Vortex Streets over the Sub-Antarctic Prince Edward Islands

Prof Ian Meiklejohn, Ms Camilla Kotze, Dr Fabio Correa, Dr Anne Lemahieu

Rhodes University, Grahamstown, South Africa

Abstract

Von Kármán Vortex Streets are commonly seen in the wake of the Prince Edward Islands (46° 54'S, 37°45'E). They are poorly documented over the entire Sub-Antarctic. Knowledge about the physical and atmospheric conditions in which these Atmospheric Vortex Streets (AVSs) are being formed is essential to elucidate the impacts of wind, specifically, the link between wind direction/strength and biological diversity. We built a database of AVS observations from Marion and Prince Edward Islands to model their formation's atmospheric parameters and prerequisite conditions. The database compiled 432 observations of atmospheric patterns, including roll vortices and AVSs, from May 2012 to September 2019 by analysing MODIS and VIIRS satellite imagery and collecting upper atmospheric data from balloon soundings. Chi-squared tests were conducted to test the association between temperature inversions and the formation of atmospheric patterns, including AVSs. Wind roses were used to identify the predominant wind direction. A binary logistic regression model was run to understand better how AVSs form. While AVSs formed under all wind directions, the dominant winds affecting the Prince Edward Islands are from the west and southwest. The dominant northwesterly winds recorded by the Marion Island weather station are most likely the result of island-wind effects. Our research showed that the most determinant predictor variables in forming AVS were the altitude of temperature inversions and the wind shear between 1 500 m and 3 000 m. Without exception, all von Kármán Vortices were preceded by cold fronts. They form when temperature inversions are below the summits of the Islands in calm conditions where little wind shear exists above the prerequisite inversion. Roll vortices form when the inversion is close to the summit altitude of the respective islands. We also contend that the genetic diversity of invertebrates on Marion Island may be partly due to wind effects.

1155

Possible links between an intense Spread-F event at a low latitude station, a geomagnetic storm and multiple substorms: a case of study

Maria Graciela Molina^1,2,3, Yamila Melendi^1,4,5, Bea Gallardo-Lacou^6,7, Paz Marcos¹, Lourdes Ruesjas¹

¹Tucuman Space Weather Center (TSWC), Facultad de Ciencias Exactas y Tecnologia (FACET), Universidad Nacional de Tucuman (UNT), Tucuman, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Tucuman, Argentina. ³Istituto Nazionale di Geofisica e Vulanologia, Rome, Italy. ⁴Departamento de Física - UNS, Bahia Blanca, Argentina. ⁵Instituto de Física del Sur (CONICET-UNS), Bahia Blanca, Argentina. ⁶NASA Goddard Space Flight Center,, Washington DC, USA. ⁷Catholic University of America, Physics Department, Washingtong DC, USA

Abstract

The magnetosphere exhibits, almost constantly, large or small perturbations such as storms, substorms, and other types of geomagnetic activity, that impact the ionospheric system. In this work, we analyze the possible relationship between ionospheric spread-F occurrence at a low latitude ionospheric station, the development of a severe geomagnetic storm, and a sequence of intense substorms.

The onset of the geomagnetic storm was observed on March 23rd at 08:00 UT, the Dst index showed a main phase that reached -163 nT on March 24th at 02:00 UT followed by a 5 days recovery phase. In addition, the auroral electrojet indices showed several consecutive intense substorms, with the SME index reaching values exceeding 2000 nT.

We observed an intense spread-F event in Tucumán ( 27° S; 65,5° W), a low latitude station located under the southern crest of the Equatorial Ionization Anomaly. The spear-F is a signature of small scale perturbations in the ionosphere, often linked to equatorial plasma bubbles originating in the equatorial region.

In our case study, the spread-F is observed post-sunset and persisting throughout the night and into the daytime, in concordance with the recovery phase of the geomagnetic storm. Notably, the occurrence of the intense spread-F was predominantly aligned with the expansion phase of the substorms observed during the event.

This study is preliminary, and we plan to add further analysis, data, and instruments, as solar activity increases. Consequently, we anticipate having more events to study in the future.

1158

Pleistocene-Holocene oceanography and glacial dynamics in Cranton Bay, Amundsen Sea, West Antarctica

Marianne G. Heberlein¹, Rebecca L. Totten², Rodrigo A. Fernández¹

¹Universidad de Chile, Santiago, Chile. ²University of Alabama, Tuscaloosa, USA

Abstract

Ice mass loss from the Amundsen Sea sector of the West Antarctic Ice Sheet has accelerated dramatically during the last century, directly contributing to increasing rates of sea-level rise. Advection of Circumpolar Deep Water (CDW) onto the continental shelf has been identified as one of the main drivers of ice loss in the Amundsen Sea Embayment. Scientific efforts to understand the magnitude and rates of CDW influence on glacier dynamics have mainly focused on large ice streams, such as Pine Island and Thwaites glaciers. However, the role of smaller basin and outlets of the ice sheet, which provide independent signals of climate and oceanographic changes in the region, are vastly understudied.

Here we present results on the analyses of sediment cores collected during two expeditions of the RV/IB Nathaniel B. Palmer (NBP 19-02 and NBP 20-02) by the International Thwaites Glacier Collaboration’s Thwaites Offshore Research team. The cores serve as archives of the oceanographic and glacial history of Cranton Bay, a shallow embayment located north of Pine Island Glacier. Using a multi-proxy approach, including magnetic susceptibility, grain size, stable isotopes, and diatom assemblage and abundance, the past glacimarine environments and oceanographic conditions in the bay are studied. Radiocarbon ages from benthic foraminifera document deglaciation by 13,000 years ago. Preliminary results indicate advection of offshore water into Cranton Bay, bringing diatoms with offshore/open water affinity during the Mid to Late Holocene. This suggests variable influence of CDW through time. The presence of a polynya in Cranton Bay today is also reflected in the sea-ice affinity diatoms of the more recent sediment. Further analysis of chemical and lithological proxies will elucidate glacial and climatic changes with varying oceanographic conditions throughout the Holocene.

1159

Antarctic Telehealth: Overcoming Isolation for Mental Health

MSc. Gabriel Lins^1,2, PhD. Jairo Werner^3,4,2, B.Sc. Thales Schaefer^4,2, MSc. Mauricio Dos Reis^4,2

¹Universidade Federal de Pernambuco, Recife, Brazil. ²SaúdeAntar - Brazilian Antarctic Program, Rio de Janeiro, Brazil. ³Universidade Federal Fluminense, Rio de Janeiro, Brazil. ⁴Instituto de Pesquisa Heloisa Marinho, Rio de Janeiro, Brazil

Abstract

In Antarctica where isolation is evident and support is scarce, mental health challenges among researchers are a pressing concern. Our project aims to address this issue head-on by developing and implementing a tele-health system tailored to the unique needs of those stationed on remote Antarctic islands.

Studies have indicated that up to 70% of individuals stationed in Antarctica experience symptoms of depression and anxiety during their time on the continent. Yet, the traditional healthcare model struggles to reach these remote locations effectively, leaving researchers vulnerable and unsupported.

To confront this issue, over the last 5 years, we have collected data using a self-assessment questionnaire on mental state, mood and sleep, developed by the group. These data provided valuable insights and early intervention opportunities. However, recognizing the need for a more comprehensive and tailored approach, based on the analysis of data already collected in recent years, we are now in the process of developing our own digital monitoring system that will ideally work, on one hand, online with tele-health system, and on the other hand, offline with questionnaires and chats to accompany and monitor users’ mental health.

This application harnesses the power of artificial intelligence, with the aim to provide an advanced support that adapts to the unique needs and challenges faced by researchers in Antarctica. Although overcoming the logistical challenges of bringing reliable internet connectivity has been no small feat, we have made a significant progress in ensuring continuous communication channels through strategic partnerships with satellite providers and innovative technological solutions.

By providing real-time support and monitoring, we not only aim to improve the mental well-being of researchers in Antarctica but to create a replicable tele-health system that transcends geographical barriers, offering vital support to those in need, regardless of their location or conditions.

1160

Scientific Literacy about Antarctic Sciences through Inclusive and Digital Scientific Outreach

Flávia Sasso Brandão¹, Silvia Cristina Dotta²

¹Universidade Tecnológica Federal do Paraná, Ponta Grossa, Brazil. ²Universidade Federal do ABC, Santo André, Brazil

Abstract

Scientific-Technological Literacy seeks to democratize access to scientific knowledge, enabling society to actively participate in scientific-technological development. There are several ways to promote Scientific Literacy, including Antarctic Polar Science through science communication.

The growing interest in polar regions is driven by the urgency to understand the effects of global climate change, especially relevant for Brazil due to its proximity to Antarctica. However, there is a lack of literature on Scientific Literacy in Polar Sciences, particularly in Antarctica, in the context of science communication, facing significant challenges in ensuring comprehensive inclusion, especially of people with disabilities.

In view of this, the Antarctic research group, InterAntar, in collaboration with a master's student from the Federal Technological University of Paraná, UTFPR, developed short videos based on the book “Antarctica, Arctic and Climate Change”, addressing 101 questions about Polar Sciences and their relationship with Brazil. The videos are made in LIBRAS (Brazilian Sign Language), Audio Description and Subtitles to include people with hearing and visual impairments and other disorders such as ADHD, CAPD, Autism and others. The videos are disseminated through social networks, allowing greater digital dissemination and aiming to transmit knowledge in an accessible way, which has had a positive impact on engagement and interaction with the public.

The initiative to produce accessible videos about Polar Sciences, especially aimed at including people with disabilities, represents a significant advance in promoting Scientific Literacy and the democratization of scientific knowledge. This innovative and inclusive approach opens doors for broader and more reflective participation by society in understanding and raising awareness about scientific issues, especially those related to climate change and polar sciences.

1167

Potential Effects of Climate Change on the reproductive success of Salpa thompsoni and Euphausia superba: a circumpolar estimation using Individual-Based Models

Javier Babbonney Valenzuela¹, PhD Andrea Piñones^2,3,4,5, PhD Ricardo Giesecke^2,3, PhD Mireia Mestre^6,3,4, PhD Juan Höfer^7,3

¹Programa de Magister en Oceanografía, Escuela de Ciencias del Mar, Facultad de Ciencias del Mar y Geografía, Pontificia Universidad Católica de Valparaíso, PO Box 2360007, Valparaíso, Chile. ²Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ³Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ⁴Centro de Investigación Oceanográfica COPAS COASTAL, Universidad de Concepción, Concepción, Chile. ⁵Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Las Palmeras 3425, Ñuñoa, Santiago, Chile. ⁶Departamento Biogeoquímica y Ecología Microbiana. Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain. ⁷Escuela de Ciencias del Mar, Facultad de Ciencias del Mar y Geografía, Pontificia Universidad Católica de Valparaíso, PO Box 2360007, Valparaíso, Chile

Abstract

The effects of Climate Change are already evident in the Southern Ocean, impacting the biota and influencing marine ecosystem functioning. Rising seawater temperature and CO₂leveles, along with changes in phytoplankton biomass (chlorophyll), are affecting the life cycle of two key zooplankton species, Euphausia superba (krill) and Salpa thompsoni (salp), resulting in opposing effects on embryo survival rates. We implemented an individual-based model (IBM) for each species incorporating the effects of temperature, CO₂ and chlorophyll-a concentration on embryo survival rate. Those IBMs were used to assess the reproductive success, measured by clutch size, of both species under present (2015 - 2020), mid-century (2045-2050) and end of the century (2095 - 2100) scenaris. The scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) were generated using an ensemble of eight Earth System Models associated with CMIP6 and three potential increase/decrease scenarios for chlorophyll-a. Result showed that Krill reproductive success significantly decreased at a circumpolar level by the end of the century under all scenarios, whereas salp reproduction improves especially at higher latitudes. Changes in reproductive success by mid-century were smaller than those by the end of the century, but they showed the same pattern in both species. These results suggest that in roughly 30 years, a decrease in krill reproduction success and an increase in salp reproduction could lead to a transition towards a salp-dominated pelagic ecosystem in certain regions of the Southern Ocean, this shift is likely to impact the functioning of these marine ecosystems.

1168

Difficulties for researchers at the beginning of their careers who make up APECS-Brasil

Dr. Paola Barros Delben¹, Raphael Fernandes Vieira², MSc Janayna de Medeiros Galvão³, Dr. Maria Jimena Cruz⁴, Dr. Amanda Leal da Silva⁵, MSc Taluany Silva do Nascimento⁶, Dr. Renan Costa de Lima⁷

¹Universidade Federal de Santa Catarina (UFSC, Brazil), Florianópolis, Brazil. ²Universidad Nacional de La Plata (UNLP, Argentina), La Plata, Argentina. ³Universidade Federal Fluminense (UFF, Brazil), Niterói, Brazil. ⁴Multidisciplinary Institute of History and Human Sciences (IMHICIHU, Argentina), Buenos Aires, Argentina. ⁵Associação de Pesquisadores Polares em Início de Carreira (APECS, Brazil), Porto Alegre, Brazil. ⁶Universidade Federal de Pernambuco (UFPE, Brazil), Recife, Brazil. ⁷Universidade Federal do Rio Grande (FURG, Brazil), Rio Grande, Brazil

Abstract

Early career polar researchers face challenges in carrying out their studies. Among the difficulties in their training and qualifications are those specific to the socio-cultural context of their country of origin, added to the natural barriers for students and young researchers. The Commission of early-career polar researchers in Brazil, APECS-Brazil, has sought to understand the profile of its community in favor of strategies to improve conditions for research and training. Objective: To identify the main difficulties for researchers at the beginning of their careers who make up APECS-Brasil. Method: Data collection through a questionnaire to 28 respondents in March 2023. Results: 48,6% declared that they have an not advanced level of English, 72,4% not advanced Spanish, languages most widespread in academia, and 65,5% state that the non-native language prevented or reduced opportunities for academic/professional work, being that 13,8% have already needed interpreters to present their results to peers. Also, 89,7% reported that they have already lost opportunities in polar research or in presenting work because they did not have the financial means to cover the costs, and 55,2% have already refused opportunities even though they knew they would receive a refund, as they did not have the immediate means to bear the costs. In addition to these data, it is observed that there are challenges related to age (27,6%) limiting opportunities. Conclusion: The main difficulties identified in this study were financial and linguistic, although issues of gender and age also permeate the problems faced by early career researchers in Brazil. Investments that expand the areas of activity, with simultaneous translation at events, or promotion of work translations and training in foreign languages, as well as the understanding that the expression “start of a career” in Brazil needs to be expanded, are important measures to solve the issues discussed.

1170

The non-evolution of cooperation: the influence of economic interests in the exclusion of the bioprospecting agenda from the International Antarctic Regime

Postgraduate student/Researcher Bruno Andrade Teixeira^1,2, Teacher/Researcher Iara Costa Leite^1,2

¹Universidade Federal de Santa Catarina, Florianópolis, Brazil. ²Programa de Pós-Graduação em Relações Internacionais, Florianópolis, Brazil

Abstract

International Political Economy theories suggest that decisions related to cooperation or non-cooperation may be linked to the degree of technological development of countries in certain economic sectors and their relative position in the international market. Based on such theories, we depart from the following research question: is there a correlation between the abdication of some States in issuing positions on bioprospecting in Antarctica and interests related to biotechnology-related economic sectors operating from their territories? The methodology was hypothetico-deductive and relied on qualitative and quantitative data. The indicators related to the dependent variable were based on countries' positioning regarding Antarctic bioprospecting, whereas indicators related to the independent variable relied on scientific and technological capacity. The latter were investigated at a macro level (innovation system), meso level (biotechnological sector), and micro level (production of Antarctic patents). Our results indicate that States heavily involved in Antarctic bioprospecting do not tend to take a stance on the issue. Non-positioning was taken as an indicator of efforts to exclude the bioprospecting agenda from the Antarctic regime, considering that countries that do not take a position benefit from the non-regulation. It was also identified that countries with a high innovation index, medium biotechnological potential, and a low number of Antarctic patents tend to take a stance on the issue, possibly linked to the search for greater knowledge of Antarctic genetic resources. Finally, countries with low innovation potential and few Antarctic patent registrations also advocate for regulation, also possibly seeing it as a mechanism to access knowledge produced by other countries, though one can question to which extent this knowledge can be absorbed in contexts marked by scarce domestic innovation networks. The non-regulation surrounding Antarctic bioprospecting indicates that some actors have more power than others to define the direction of the Antarctic regime by excluding certain agendas.

1174

Detecting signals of adaptive selection of an invasive versus a native springtail on sub-Antarctic Marion Island

Miss Shilpa Parbhu¹, Dr Arsalan Emami-Khoyi¹, Dr Charlene Janion-Scheepers^2,3, Prof Peter Teske¹, Prof Peter Convey^4,1,5, Prof Bettine Jansen van Vuuren¹

¹University of Johannesburg, Johannesburg, South Africa. ²University of Cape Town, Cape Town, South Africa. ³Iziko Museums of South Africa, Cape Town, South Africa. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Biodiversity of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile

Abstract

Springtails are important soil-dwelling microarthropods with a global distribution. They play a role in nutrient cycling and are commonly used as bioindicators of ecosystem health. The collembola Isotomurus maculatus and Folsomotoma marionensis are our study organisms. Isotomurus maculatus has a natural distribution that includes Europe and North America, with some individuals present in the Western Cape, South Africa, while F. marionensis is endemic to sub-Antarctic Marion Island. Isotomurus maculatus was introduced to Marion Island in the late 1970s and is an invasive species on the island. On Marion Island, there are no endemic vertebrate herbivores, but springtails, invertebrate herbivores, are abundant and, therefore, fulfil the role of herbivory, making them an ecologically important group on the island. Since I. maculatus is native to regions that are hot and dry, how did this springtail adapt to a cold and harsh environment such as that on Marion Island? We aimed to answer this by conducting a comparative study, identifying possible signals of adaptive selection, by sequencing the transcriptome of I. maculatus and F. marionensis under different thermal conditions. We applied a comparative transcriptomic approach to identify signals from genes and metabolic pathways involved in local adaptation to pinpoint the biochemical mechanisms that facilitate adaptation to Marion Island. The genomic basis of adaptation in invasive species is not well understood, therefore, the implications of this study are far-reaching as it will help to inform the management of invasive species.

1178

Antarctic Space Analogue Based on Health and Medical Issues in the Global Exploration Roadmap by the the International Space Exploration Coordination Group

Eojin Yi*^1,2, Joowoong Park³, Kyunghwan Kim^4,5, Woo Seok Choi⁶

¹aSSIST University, Seoul, Korea, Republic of. ²Korean Society of Polar Medicine, Seoul, Korea, Republic of. ³Korea Aerospace Research Institute, Daejeon, Korea, Republic of. ⁴MoonLeap Space System Inc., Seoul, Korea, Republic of. ⁵German Aerospace Center (DLR), Köln, Germany. ⁶Keyu Internal Clinic, Daejeon, Korea, Republic of

Abstract

As human space exploration steps further into deep space through the Artemis mission and Moon to Mars project, the importance of healthcare and medical considerations in space is increasingly emphasized. We review the health and medical issues included in the Global Exploration Roadmap (GER) by the International Space Exploration Coordination Group (ISECG). Among the critical technologies listed, parallels between Antarctic expeditions and space missions arise in medical support, behavioral performance, health risks management, life support system, and crew health management. It could be connected the experiences of medical issues encountered during Antarctic missions to the health management strategies for long-duration spaceflights and missions. By applying these 'Antarctic insights,' we could propose a basic framework for related health issues in long-duration spaceflight, habitat design, and crew welfare, and so on.

*This analysis not only highlights the importance of interdisciplinary applications in tackling the challenges of human space exploration but also underlines the Antarctic experience as an useful analogue model for deep space missions.

1181

Permafrost and Active Layer Monitoring in the Ahlmanryggen and Jutulsessen regions of Western Dronning Maud Land.

Prof Ian Meiklejohn¹, Dr Christel Hansen², Mr Nicholas Foxon¹

¹Rhodes University, Grahamstown, South Africa. ²University of Pretoria, Pretoria, South Africa

Abstract

In much of Antarctica, the geomorphology provides a template, or habitat, for biodiversity at various spatial scales from the micro- to landform scales. Globally, permafrost has been recorded to be warming (Biskaborn et al. 2019). Current climate warming thaws the uppermost permafrost in many regions and creates feedback in the global climate system. This project established monitoring sites in the Antarctic to develop regional understanding of changes in permafrost temperature, active layer processes, as well as biological and climate interactions.

At seven nunataks, point-specific measurements were made of ground temperature, moisture and soil movement rates between 2007 and 2018. The active layer varies in depth from less than 20 cm in the interior of the Ahlmanryggen at altitudes above 1000m to greater than 60cm at locations near the coast (e.g. Robertskollen), at altitudes below 400m. The mean annual ground temperature in the study area ranges from -8.7°C at the coast to -17.9°C, at over 1 200 masl in the interior. A great deal of variability exists between study sites. Annual ground thermal minima are more variable than the maxima. Elsewhere in the Antarctic, permafrost degradation and thickening of the active layer, particularly in the Antarctic Peninsula.

The recorded temperature data were supplemented by MODIS and VIIRS optical and infrared imagery that showed that synoptic-scale weather conditions affected active-layer temperatures, particularly in the second half of summer (in December and January). Increased snow cover from 2015 is contended to have contributed to slightly cooling ground temperatures. It is not immediately clear if the observed trends represent short-term variations or if they signify long-term warming. However, when considered together with ice-mass balance studies and sea-ice trends, it is most likely that the trends observed from borehole data in Western Dronning Maud Land are part of content-wide or global warming system.

1182

Ice Lens Formation in Antarctic ice shelves

Marcelo Marambio^1,2, Shelley MacDonell³, Nelson Moraga², Irina Rogozhina^1,4

¹Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile. ²Universidad de La Serena, Departamento de Ingeniería Mecánica, La Serena, Chile. ³Waterways Centre for Freshwater Management, University of Canterbury and Lincoln University, Christchurch, New Zealand. ⁴Norwegian University of Science and Technology, Department of Geography, Trondheim, Norway

Abstract

In the context of climate change, it is essential to understand variations in the external factors that can alter the thermal and structural balance of ice shelves, leading to their destabilization and potential collapses. These changes can increase the overall density and thus the weight of ice shelves due to changes in the air-ice-liquid relationship inside their structure and impose additional strain on zones of pre-existing weaknesses, resulting in development of fractures and iceberg calving.
The objective of this work is to identify main drivers of the loss of thermal equilibrium in Antarctic ice shelves through a combination of numerical modeling of their internal composition and ice core measurements, using the Müller ice shelf in the Antarctic Peninsula as an example. In this light, we use a new finite volume model, including liquid-solid phase transition, to analyze how changes in the atmospheric factors have impacted the internal properties of the ice shelf over recent years. The model ensemble is driven by the ERA5 and RACMO atmospheric forcing to account for uncertainties in the meteorological data.
The results of the model ensemble are then compared with Müller ice shelf ice core stratigraphy data and contrasted by the outputs from an independent energy and mass balance model. Here we present a detailed analysis of the available energy fluxes for surface melting, evolution of surface temperature and internal ice shelf regimes, and reconstruction of ice lens formation and distribution. A thick lens predicted by the developed model coincides in size and position with the largest ice lens in the ice core, being caused by a high energy level before extraction (2017 - 2018). In addition, the greatest thickness of the ice lens is directly related to the highest energy level recorded in the summer of 2019 - 2020.

1186

Impact of increasing warm weather events on penguin reproductive behaviour across the Antarctic Peninsula

Cláudia Ribeiro¹, Irina Gorodetskaya², José Xavier³, Claudio Durán-Alarcón², Lucas Krüger⁴

¹University of Porto, Porto, Portugal. ²Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Matosinhos, Portugal. ³Marine and Environmental Sciences Centre (MARE) – University of Coimbra, Coimbra, Portugal. ⁴Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

Polar regions are experiencing increased warming due to climate change, which represents a significant environmental concern. This climatic shift presents major consequences to key regional climate variables, such as snow cover and sea ice, which are essential for the local ecosystems. Anomalous events, such as rainfall and surface melt, are threats to native wildlife, particularly penguins, since chicks' feathers, once wet, provide little insulation, leaving the young penguins in danger of freezing to death. The extreme warm event witnessed in the Antarctic Peninsula in February 2022 serves as a critical case study for assessing the impact of extreme weather events on penguin populations. This presentation focuses on the impact of rainfall and surface melt in the western Antarctic Peninsula on penguin breeding success, particularly contrasting the years with extreme events with the climatological data since 1950. Preliminary analysis shows a decrease in the breeding success of Adélie and Emperor penguins, which were previously found to be dependent on rainfall at other locations. In contrast, Gentoo and Chinstrap penguins show an increase or unclear trends. Understanding the impact of warm weather events on penguin population dynamics may help us predict the consequences of environmental shifts for different species of penguin, with implications for conservation planning and ecosystem management.

1189

Revealing unnoticed passengers: Monitoring antarctic trajectory ship hulls as species transports and their detection by eDNA

Dra Zambra López-Farrán¹, Juan Pablo Rodríguez^2,3, Francisco Bahamonde^3,2, Dr. Luis Miguel Pardo^1,4, Dra. Victoria Suescún¹, Valeria Prieto¹, Dr. Andrés Mansilla^2,3, Dr. Jorge Navarro^1,4, Dra. Leyla Cárdenas^1,5

¹Research Center Dynamics of High Latitude Marine Ecosystems (IDEAL), Universidad Austral de Chile, Valdivia, Chile. ²Universidad de Magallanes, Antarctic and Subantarctic Marine Ecosystems Laboratory, Punta Arenas, Chile. ³Cape Horn International Center for Global Change Studies and Biocultural Conservation (CHIC), Universidad de Magallanes, Punta Arenas, Chile. ⁴Institute of Marine and Limnological Sciences, Universidad Austral de Chile, Valdivia, Chile. ⁵Institute of Environmental and Evolutionary Sciences, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile

Abstract

The introduction of invasive species in Antarctica, both terrestrial and marine, is one of the most concerning issues for the conservation of the Antarctic ecosystem. Usually, the introduction of non-native species is associated with anthropogenic activities, because they facilitate dispersion into new geographic zones. Over the past few decades, activities such as fisheries, tourism, and scientific research have significantly increased in both maritime and terrestrial Antarctica. This surge has resulted in numerous ships and airplanes entering Antarctica, thereby providing more opportunities for non-native species to invade the continent. The combination of increase in anthropogenic activity and rising environmental and maritime temperature in Antarctica elevates the likelihood of introduction and settlement of invasive exotic species. Therefore, the aim is to identify the species that are transported attached to the hulls of ships bound for Antarctica and to determine the biofouling community present on ships transiting the Southern Ocean. Samples were collected from ships with Antarctic itineraries before, during, and after their visits to Antarctica. Videos recordings were utilized to assess fouling-biofouling coverage, while macroscopic organisms and environmental DNA (eDNA) samples were obtained from vessels to identify the transported organisms. In stern, fouling coverage ranged between 0 (No visible fouling. Hull entirely clean) to 5 (Very heavy fouling. Diverse assemblages covering most of the visible hull surfaces). In stern, before arriving in Antarctica, green and brown Algae were identified, whereas during Antarctica, green and brown algae, amphipods, copepods, bivalves and diatoms were identified. For eDNA analysis, COI and 18S markers were amplified. Metabarcoding analysis revealed a in community composition between before and during antarctica; however, the community remained similar between during and after antarctica. Although these findings are preliminary, they underscore the importance of monitoring and characterizing the biofouling process in the Southern Ocean. Funding and support: Fondap-IDEAL 15150003

1193

Investigative study of Black Carbon Aerosol concentration variation at Indian Research Station – Bharati, Antarctica

Mr. Satyajit Singh Saini¹, Dr. Anand Kumar Singh²

¹Indian Institute of Technology Roorkee, India, Roorkee, India. ²National Centre for Polar and Ocean Research, Goa, India

Abstract

Earth’s atmosphere has been deeply impacted because of the disturbance in its heat budget caused by radiative forcing, and one of the prime contributors is black carbon (BC). Aeolian processes transport it to a long-range and it reaches the coasts and inlands of Antarctica. To achieve the Sustainable Development Goals of United Nations, it becomes very crucial to monitor the concentration variations of BC in the pristine and sensitive environment of Antarctic continent over a long-term to study the implication of aerosol and the variability in its concentration. For measurement of the BC aerosol, an AE-33 aethalometer of Magee Scientific is operational on a regular basis since starting of austral summer of the year 2018-19 at the Indian Antarctic Station Bharati which is located at 69^o 24.41’S & 76^o11.71’E. The Antarctic summer season marks the increased activity at Bharati and neighboring stations Zhongshan, Progress and Law Base summer station. Additional to it, at least three supply vessels in the close vicinity of aerosol observatory contribute to an increased concentration level of BC. This work highlights the changes in the BC concentration, particularly the diurnal and seasonal variations. Emphasis has been given to understand the effects of local anthropogenic activities in the Larsemann Hills area during the austral summer season. Also, the long-range transport from patagonia region was studied and solar zenith angle was considered for being a probable driver.

1194

Distribution of some locally rare moss species in the Argentine Islands - Kyiv Peninsula region, western Antarctic Peninsula

Hanna Yevchun¹, Jerzy Smykla², Ivan Parnikoza^1,3

¹State Institution National Antarctic Scientific Center, Kyiv, Ukraine. ²Institute of Nature Conservation, Krakow, Poland. ³Institute of Molecular Biology and Genetics, Kyiv, Ukraine

Abstract

Biodiversity hotspot is one of the criteria for identifying representative areas for better practices of biodiversity protection. This is especially true for protecting the areas with important or unusual assemblages of species in the Antarctic Peninsula, which is particularly vulnerable to climate change impacts. There are 66 species and one variety of mosses currently known for western coast of the Antarctic Peninsula (Ochyra et al., 2008). Some information has accumulated on the distribution of rare mosses in many Antarctic regions including the Argentine Islands - Kyiv Peninsula region, although there is no survey that would systematize existing data on this topic.

Here we present a survey of published data on distribution of some (22) rare moss species in the area of the Argentine Islands - Kyiv Peninsula, a boundary between the northern and central biogeographic regions of the western Antarctic Peninsula, which makes it special in terms of edge effects. We systematized data from databases and publications, and identified rare moss species hotspots. The rarity of species was defined according to their respective entire-Antarctic frequency, following Ochyra et al. (2008). We found out that all 22 species analyzed were very rare/rare in the abovementioned region, although only three of them were considered very rare/rare in the entire Antarctic, while other were either “occasional” (13.6% of studied species), “frequent” (31.8%), or “common” (40.9%). Analysis of herbarium specimen databases has identified four hotspots in the diversity of those rare mosses that have already been processed: Cape Tuxen, Darboux Island, Petermann Island and Galindez Island, with nine, eight, five and four of rare moss species records respectively. Further studies of the distribution of rare species of mosses would help facilitate the identification of valuable Antarctic areas and develop best polices of their protection, including through creating Antarctic Specially Protected Areas.

1196

Troll Observing Network Drone Service

Dr. Rune Storvold¹, Stig Flått², Dr. Kenichi Matsuoka², Andreas Tøllefsen¹, Dr Stian Solbø¹, Dr Christina Pedersen²

¹NORCE Norwegian Research Centre, Tromsø, Norway. ²Norwegian Polar Institute, Tromsø, Norway

Abstract

The emergence of drones has given scientists a new powerful tool for efficient data collection with a small environmental footprint. The first use of drones for science in Antarctica started almost 20 years ago. Since then, drone technology has undergone a rapid development and matured. Still, we are far from exploiting its full potential. Challenges are still the remote and harsh environment faced in Antarctica and the lack of international regulation in particular for larger drones operating over long distances.

TONe (Troll Observing Network) is an infrastructure project funded by Research Council Norway consisting of eight science observatories and a drone service that will extend the geophysical and environmental data collection capabilities in Dronning Maud Land. The drone service will have Remotely Piloted Aircraft Systems with a range of about 1000 km and endurance up to 10 hours. In addition smaller electric multirotor and fixed wing drones will be deployed as part of the service. The drone service is set up to support research projects through data collection with advanced instrumentation that ordinary research projects otherwise would not be able to conduct on their own. Yearly deployments serving multiple projects will reduce costs for individual projects as well as reducing risk through the use of professional drone operators with experience of conducting drone operations in polar environments.

The drone systems are adaptable to different research needs, and will be equipped with basic meteorological sensors, hyperspectral imager, aerial camera, broadband radiometers, and VHF and microwave radar sounding systems to support the Troll Integrated Cloud Observatory, Fimbulisen Ice Shelf Observatory, Seabird Monitoring Observatory and the Ocean Moored Observatory. The service is set up to support research projects needing airborne data in Dronning Maud Land region. The plan is to start deployments at the Troll Station starting in the 2026/27 season.

1199

Journey to Antarctic Literacy: Transforming Scientific Papers in Storybooks for Effective Climate Change Communication

Dr. Elaine Alves dos Santos, professor Heitor Evangelista

Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Given the climate emergency, it becomes urgent to organize and implement effective scientific communication. Scientific communication needs to be reliable and simple. Scientists need to communicate in a way that an 8-year-old child can understand.

In this way, we wrote a children's book inspired by scientific papers containing content such as the association of Climate Change and Antarctica, the concept of atmospheric rivers, and a subtle approach to scientific denialism; as well as presenting Antarctic fauna.

To translate scientific language into accessible, fun, exciting, and engaging language, we used literary writing resources such as the Hero's Journey. The hero's journey is a narrative concept developed by mythologist Joseph Campbell, which describes a common structure found in many epic and mythological stories around the world. This structure has been widely used in the creation of books and movies. It was a pleasurable challenge to insert scientific content to meet the twelve steps of the Hero's Journey.

The book tells the story of a missing petrel that had been carried away by stronger winds than its wings could handle and, disoriented, had to change its route. This is a true case because this petrel was sighted at the Criosfera1 remote laboratory (https://www.criosfera1.com/)/Brazilian Antarctic Program (84°S,79°29'39"W, 1250 m A.S.L.) on December 11, 2022. While the petrel was missing, the petrels in the nest murmured: those who believed in climate change worried about Will and suspected he was in danger, and those who did not believe said that the Petrel just wanted to cause trouble and become popular in the nest. With this context, we can subtly emphasize the concept of scientific denialism, which needs to be combated. There are paragraphs that entertain and educate. The book is under review and will be published in English and Portuguese versions.

1200

Early Career Researchers as ambassadors of Polar Literacy: the importance of education and outreach

José Abreu^1,2,3, José P. Queirós^1,2,3, Céline Rodrigues^1,4, Débora Carmo¹, Diana Rodrigues¹, Diogo Francisco^1,2, Graça S. Nunes^1,5, Laura Lopes^1,2, Lucas Bastos^1,2,6, Márcia Dias¹, Maria Soares^1,7, Mariana Molinari^1,8, Mariana Quitério^1,2, Ricardo S. Matias^1,8,9, Rita Quelha^1,8, Santiago Villalobos^1,10, Sara Lopes-Santos^1,2, Hugo R. Guímaro^1,2,3, Joana Fragão^1,2,3

¹Association of Polar Early Career Scientists, Portugal, Portugal. ²University of Coimbra, MARE - Marine and Environmental Sciences Centre/ARNET – Aquatic Research Network, Department of Life Sciences, Coimbra, Portugal. ³British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, CB3 0ET, Cambridge, United Kingdom. ⁴Faculty of Social and Human Sciences, NOVA University, UNL, Lisboa, Portugal. ⁵Faculty of Sciences, University of Lisbon - MARE - Marine and Environmental Sciences Centre, Lisboa, Portugal. ⁶Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, D-27570, Bremerhaven, Germany. ⁷Departamento Ciências da Vida, Universidade de Coimbra, Coimbra, Portugal. ⁸ICBAS, School of Medicine and Biomedical Sciences, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal. ⁹CIIMAR, Interdisciplinary Centre for Marine and Environment Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal. ¹⁰University of Akureyri, Akureyri, Iceland

Abstract

Among the global climate challenges that we face as a species (e.g. changes in circulation patterns, warming, acidification), one critical issue that emerges is the disinformation of the general public about polar regions, their importance and the ongoing climate change impacts. Currently, these topics and the downturns associated with, have never been so much mentioned in daily news (i.e.: newspapers, tv, debates, forums, etc.) and social media. Yet, the real knowledge or perception of the society regarding these issues remains uncertain. Within this context Early Career Researchers (ECRs) can play a crucial role in enhancing education and outreach activities about polar regions, bridging these gaps. They are vital contributors to scientific development and a fundamental part to combat misconceptions. In this presentation we aim to highlight work performed by ECRs from APECS Portugal during the International Polar Weeks in schools (since 2009), institutes and forums, annual workshops to university students, and the use of social media to, disseminate science and evaluate the potential of this platform to evaluate public knowledge and shape future generations. Furthermore, we will present the results of a questionnaire that APECS Portugal has been running to test the knowledge of the public and students, about the Arctic, Antarctic, and the role of Portugal in polar research. It also collected the public view on how information is transmitted in social media platforms. The results revealed a general belief and recognition of climate change as a global emergence and a lack of knowledge about the true impacts and characteristics of polar regions. In addition we want to showcase the importance of the scientific, educational, and outreach activities conducted by ECRs and emphasise their role as ambassadors of accurate knowledge.

1202

A long-lived, proglacial refugium at Lake Joyce, Antarctica

Tyler Mackey¹, Sasha Leidman²

¹University of New Mexico, Albuquerque, USA. ²Rutgers University, New Brunswick, USA

Abstract

Antarctic ice-covered lakes of the McMurdo Dry Valleys contain productive microbial communities with microinvertebrate assemblages, but lack larger invertebrates – with one intriguing exception. The cyclopoid copepod Diacyclops joycei has been found in Lake Joyce, a small perennially ice-covered proglacial lake in Pearse Valley, southern Victoria Land, but in no other similar lakes regionally that would appear to provide suitable habitat. The lakes of the McMurdo Dry Valleys are documented to have fluctuate in size over past millennia in response to climate change, and a possible explanation for the current distribution of D. joycei is that this is a relic of a previously more widespread population.

In this contribution we explore the water sources and bathymetry of Lake Joyce to assess its potential as a refuge for D. joycei. The key requirement is a mechanism that allowed suitably fresh, year-round liquid water to persist through previous climate-driven hydrologic cycles. Lake Joyce has glacier contact for its full water column, with brackish waters (~7.8 PSU) abutting Taylor Glacier at maximum lake depths. Brackish water δ²H and δ¹⁸O values suggest that they originated as evaporatively concentrated lake margin waters that accumulated in the deep lake due to hyperpycnal flows rather than being a relic of higher salinity at lower lake levels. Fresh water sourced from glacier melt may have further maintained a suitable freshwater Diacyclops habitat through changes in regional climate since the retreat of large glacial paleolakes that rendered nearby moraine- or bedrock-dammed lakes too saline. These results suggest that persistent ice-dammed lakes may provide refugia for freshwater organisms in arid periods of low habitat connectivity.

1206

Deciphering microbial biogeography and diversification in the Southern Ocean: Key insights from marine metaorganisms.

Dr Guillaume Schwob^1,2,3, MSc Mélanie Delleuze^1,2,4, MSc Sebastián Rosenfeld^1,2, Dr Nicolás I. Segovia^5,6, Dr Claudio González-Wevar^7,8, Dr Thomas Saucède⁹, Dr Paul Brickle¹⁰, Dr Karin Gérard^11,12, Dr Elie Poulin^1,2,3, Dr Léa Cabrol¹³, Dr Julieta Orlando^1,2

¹Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ²Department of Ecological Sciences, Faculty of Sciences, University of Chile, Santiago, Chile. ³Institute of Ecology and Biodiversity, Santiago, Chile. ⁴Marine Biology Lab, CP160/15, Université Libre de Bruxelles (ULB), Brussels, Belgium. ⁵Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile. ⁶Instituto Milenio en Socio-ecología Costera (SECOS),, Coquimbo, Chile. ⁷Institute of Marine Sciences and Limnology (ICML), Faculty of Science, Universidad Austral de Chile, Valdivia, Chile. ⁸Research Center Dynamics of High Latitude Marine Coastal Ecosystems Fondap IDEA IDEAL, Universidad Austral de Chile, Valdivia, Chile. ⁹Biogeosciences, UMR 6282, University Bourgogne Franche-Comté, CNRS, EPHE, Dijon, France. ¹⁰South Atlantic Environmental Research Institute, Stanley, Falkland Islands (Malvinas). ¹¹Laboratory of Antarctic and Subantarctic Marine Ecosystems, Faculty of Sciences, University of Magallanes, Punta Arenas, Chile. ¹²Cape Horn International Center,, Puerto Williams, Chile. ¹³Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France

Abstract

The intricate evolutionary dynamics between metaorganisms and their microbiomes is a burning topic in microbial biogeography, shaping microbial spatial distributional patterns and evolutionary trajectories. Detecting specific host-microbe interactions and assessing whether they lead to co-diversification suffer multiple drawbacks, including complex host microbial communities, multiple environmental driving factors, poorly-resolved host population structures, and extensive evolutive timescales among hosts. While co-diversification is thoroughly explored on land, marine studies in logistically challenging regions like the Southern Ocean (SO) are scarce. Yet, this region hosts a variety of recently diverged macroorganisms with well-studied phylogeographic structures, providing valuable models for understanding the role of hosts in microbial biogeography and diversification processes.

Through a conglomerate of studies, we leverage various natural systems consisting of distinct invertebrates and vertebrate host genera: the sea urchin Abatus, the limpet Nacella, and the plunderfish Harpagifer. These models represent nine species distributed across three provinces of the SO structured by two oceanographic features: the Patagonia and Kerguelen islands connected by the Antarctic Circumpolar Current, and the West Antarctic Peninsula isolated by the Antarctic Polar Front. We combined community-wide surveys of microbiomes using 16S metabarcoding and intra-OTU microdiversity analyses, enabling robust estimations of phylogeographic and migration parameters, as well as fine-scale distributional and phylogenetic congruence patterns.

Our results bridge the gap between microbial and macrobial ecology by revealing strong congruency between distribution patterns at the population level, shaped by the same oceanographic structures and ecological processes, and by the specialization degree of the bacterial taxa. We also report co-phylogeny signals at microdiversity resolution between predominant bacterial symbionts and host phylogenies, indicating an intimate symbiotic relationship and shared evolutionary history with hosts. We propose that the relatively recent diversification of marine macroorganisms across the SO may have led to the diversification of their bacterial symbionts, exhibiting patterns mirroring the host phylogeny.

MI-BASE ICN2021_002

1207

Recent temperature trends and implications for biodiversity in Antarctica’s ice-free bioregions

Eva Bendix Nielsen, Gabrielle Koerich, Dr Marwan Katurji

University of Canterbury, Christchurch, New Zealand

Abstract

Changes in air temperature within ice-free regions, which host most of Antarctica terrestrial biodiversity, have significant influence on species distributions and community composition by affecting the temporal availability of meltwater. These areas sometimes span less than 1 km, thereby making them highly effected by local processes. Availability of high resolution climate data becomes thus crucial to understand localised changes.

Here, we present a spatial analysis of temperature trends and changes in degree days for the ice-free areas of Antarctica for 2003-2021. With a focus on the 16 Antarctic Conservation Biogeographic Regions, we use the satellite derived near-surface air temperature product AntAir ICE with a 1km grid resolution to investigate these changes. Our data shows a positive austral summer trend for 12 out of the 16 bioregions. A significant annual mean warming trend is observed in the Ellsworth Mountains (ACBR 11) and South Victoria Land (ACBR 9) with the latter being 0.08 °C/Yr. Central South Antarctic Peninsula (ACBR 3) is experiencing significant cooling of -0.05 °C/Yr. Diversity metrics reveal that ACBR 3 and 9 are amongst the most biodiverse bioregions, contrasting with ACBR 11, which exhibits the lowest diversity. However, sampling bias in Antarctica are significant, and the Peninsula and Victoria Land have numerous scientific surveys and stations, contributing to more comprehensive biodiversity records. In contrast, the Ellsworth Mountains remain largely understudied, resulting in a notable gap in biodiversity knowledge. Our findings underscore two critical points: i. The regions within ACBR 3 and 9 exhibit promising potential as sentinel sites for investigating biota responses to both warming and cooling trends; ii. There is substantial risk of overlooking significant biological changes in Ellsworth Mountains due to the lack of data for this region. This underscores the urgency of addressing this knowledge gap to better preserve the likely unique biota of ACBR 11.

1208

Fit for an emperor: are icebergs key to colony size and stability for emperor penguins?

Dr. Michelle LaRue¹, Ms. Monique Nixon¹, Dr. Leo Salas², Dr. Nadav Nur², Ms Rose Foster-Dyer¹, Ms Alexandra Strang¹, Mr Arek Aspinwall¹, Ms Emilija Reuter¹, Ms Alexa Hasselman¹, Ms Georgia Gwatkin¹, Ms Shanae Kirk¹, Dr Clare Adams³, Dr Sharon Stammerjohn⁴, Dr David Ainley⁵

¹University of Canterbury, Christchurch, New Zealand. ²Point Blue Conservation Science, Petaluma, USA. ³Victoria University of Wellington, Wellington, New Zealand. ⁴University of Colorado Boulder, Boulder, USA. ⁵HT Harvey & Associates, Los Gatos, USA

Abstract

Emperor penguin colonies occur mostly on land-fast sea ice and are evenly-spaced around Antarctica, indicating that intraspecific competition affects their distribution. However, emperor penguin colonies range in size from mere dozens to >25,000 birds with large variation in inter-annual colony counts, including presumed complete absences (i.e., no birds showing up to breed). We assess the effect of fine-scale drivers of nesting habitat stability. Specifically, we hypothesized that emperor penguin colony presumed absence would be correlated with fine-scale habitat features, such as numbers and sizes of icebergs within ~20 km of the colony, which would anchor fast ice habitat in place. We suspect that smaller colonies and presumed absences will be more likely associated with more variable iceberg presence. We searched for, counted, and categorized by size, the icebergs at all known emperor penguin colonies (discovered prior to 2015; n = 60) for the entirety of the satellite record that overlapped colony locations (2002-2023), and compared iceberg characteristics to fast ice region, colony type (e.g., windward bay, ice shelf), presumed absence and colony size. We found most presumed absences within the Bellingshausen and Amundsen Seas, which in the absence of capes and islands depend most icebergs; and these regions had few, but not fewest, icebergs. Antarctic-wide, presumed absences were highest in colonies situated on land and on ice shelves. Data from this study will add detail to future studies and help us to understand how the different colonies may respond to their changing environment.

1209

Revealing climate-driven adaptations, phylogeography, population structure, and phenological dynamics of Parochlus steinenii, the winged Antarctic midge in Antarctic and Sub-Antarctic ecosystems

Tamara Contador^1,2,3, Melisa Gañan^1,2,4,3, Claudia Maturana^1,2,3, Hugo Benítez^5,1,2, Brenda Riquelme^1,2,3, Katherine Chavez^1,2,3, Carolina Pérez Troncoso^1,2,3, Javier Rendoll^1,2,3, Karin Gerard^1,2, Peter Convey^6,1,2,7

¹Millenium Institute of Antarctic and Subantarctic Biodiversity (BASE), Santiago, Chile. ²Cape Horn International Center, Puerto Williams, Chile. ³Laboratorio Wankara de Ecosistemas Subantárticos y Antárticos, Universidad de Magallanes, Puerto Williams, Chile. ⁴FEHM-Lab (Freshwater Ecology, Hydrology and Management), Departamento de Biología Evolutiva, Ecología i Ciencias Ambientales, Facultad de Biología, Universidad de Barcelona, Barcelona, Spain. ⁵Laboratorio de Ecología y Morfometría Evolutiva, Centro de Investigacion de Estudios Avanzados del Maule, Universidad Catolica del Maule,, Talca, Chile. ⁶British Antarctic Survey, Cambridge, United Kingdom. ⁷Department of Zoology, University of Johannesburg, Johannesburg, South Africa

Abstract

Antarctic and sub-Antarctic regions provide invaluable insights into the impacts of climate change on ectothermic organisms' evolutionary history, distribution, ecology, and phenology. Within these ecosystems, the terrestrial fauna is represented by small invertebrates, notably including only two native insect species: the winged Antarctic midge, Parochlus steinenii, and the wingless Belgica antarctica. While the winged midge thrives in the maritime Antarctic and extends its range to the sub-Antarctic islands of South Georgia and southern South America, B. antarctica is endemic to Antarctica. Our research focuses on comprehensively understanding the adaptations of the winged midge to both current and anticipated climate-driven changes across various ecological scales. Specifically, we investigate phylogeographical patterns, population structure and density, habitat preferences and phenological patterns of P. steinenii in the South Shetland Islands, austral Chile, and South Georgia. Our findings reveal marked genetic diversity and structure across the midge's distribution, with notable divergence between South America and Antarctica/South Georgia dating back to the mid-Pleistocene (~1.4 Ma). Population analyses using microsatellites conducted on samples from multiple lakes show distinct genetic clusters, highlighting both localized gene flow and isolated populations. Presently, P. steinenii occupies ice-free lakes and rivers at sea level in Antarctica and South Georgia, whereas in South America, it is restricted to high mountain ecosystems. Adults are mainly found in shallow lake margins, although population densities exhibit regional and microhabitat variability driven by physico-chemical parameters, particularly thermal patterns. In the maritime Antarctic, its lifecycle spans up to four years, contrasting with a one-year lifecycle in southern Chile, highlighting its sensitivity to thermal variations. P. steinenii emerges as a sentinel species for climate change, with potential implications for its distribution, population connectivity, and phenological dynamics. Understanding these dynamics is crucial for predicting and mitigating the broader ecological impacts of thermal change at different scales in Antarctica.

1210

Advances in antarctic environmental monitoring: The LEMA network as a tool for studying the effects of global climate change on the Antarctic Peninsula and its surroundings.

MSc(c) Sebastián Alfaro Gómez^1,2, MSc(c) Pamela Maldonado Venegas^1,2, Bastián Oyarce Vejar³, Cristofer Huenchumán Aguayo³, Ricardo Faúndez Alcalde³

¹Centro de estudios Avanzados en Zonas Áridas (CEAZA), La Serena, Chile. ²Centro de Investigación GAIA Antártica (CIGA UMAG), Punta Arenas, Chile. ³Instituto Antártico Chileno (INACH), Punta Arenas, Chile

Abstract

The government of Chile, through the Chilean Antarctic Institute (INACH), has implemented an extensive and robust environmental monitoring network over the past three years, deployed across the Antarctic Peninsula, South Shetland Islands, and Union Glacier. The Latitudinal Network of Multiparametric Stations in Antarctica (LEMA) represents a state-driven, permanent initiative that provides meteorological, oceanographic, and glaciological data measured in situ in the Antarctic territory to the scientific community and the general public. This program aligns with the National Antarctic Policy, contributing to the understanding of the effects of global climate change in the Antarctic Peninsula and its surroundings.

Currently, the network comprises 13 automatic monitoring stations, whose installation and periodic maintenance are made possible through a coordinated effort among various institutions of the country (INACH, Meteorological Directorate of Chile and Armed Forces). The stations have been designed for rapid deployment, capable of withstanding adverse climatic conditions, and are energy-autonomous, recording and transmitting data even during the winter season.

The LEMA network began its trial phase with four stations installed during the 2022 summer campaign. During its first year of operation, some sensors and the power system experienced failures, which were addressed in subsequent Antarctic campaigns, resulting in the installation of nine additional multiparametric stations (Figure). By its third year, the network operates efficiently, transmitting data every six hours to a public web platform for visualization and data download (www.redsensoresinach.cl).

INACH provides the LEMA network with a robust computational infrastructure, instrumentation laboratory, and a team of monitoring experts, ensuring the operational continuity of the network. With over a year of uninterrupted measurements in Antarctica, the LEMA network has recorded extreme meteorological events (e.g. heatwaves) in previously unmonitored areas, providing relevant and novel information to the international scientific community.

Uncaptioned visual

Figure: AWS installation on South Shetland Islands, Antarctica. Source: Bastián Oyarce (INACH), 2024.

1212

Seven years of ionospheric scintillation monitoring using software-defined radio receiver in Antarctica

Rayan Imam¹, Lucilla Alfonsi¹, Luca Spogli^1,2, Claudio Cesaroni¹, Iman Ebrahimi Mehr³, Alex Minetto³, Fabio Dovis³

¹Upper Atmosphere Physics and Radiopropagation Unit, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy. ²SpacEarth Technology, Rome, Italy. ³Department of Electronics and Telecommunications, Politecnico di Torino, Torino, Italy

Abstract

Since 2016, a custom-built software-defined radio (SDR) receiver has been monitoring ionospheric scintillations affecting Global Navigation Satellite Systems (GNSS) signals at SANAE IV station (71°40′22″S, 2°50′26″W, geomagnetic dipole latitude 66°45′S). These scintillations occur when the GNSS trans-ionospheric signals pass through irregularities in the plasma density of the ionosphere. The use of such technology, i.e. SDR, gives high flexibility and control over the scientific measurements’ acquisitions and processing, which commercial receivers usually lack.

The monitoring system is composed of the SDR working in parallel with a commercial GNSS scintillation monitoring receiver. The two receivers share the same antenna and thus receive identical GNSS signals. The two receivers independently monitor the ionosphere and log their recordings continuously in ionospheric scintillation monitoring records containing the amplitude and phase scintillation indexes estimated by the two receivers, available at a 1-minute cadence, in addition to other higher rate raw data collections.

In this work, we process all the 1-minute data in the period 2016-2019 characterized by low solar activity. We compare the two receivers’ performances by comparing the scintillation climatological maps obtained from each receiver independently. We sort the maps according to geomagnetic conditions. We analyse the differences in the estimated indexes, and comment on the occurrences of significant deviations in the indexes estimated by the two receivers. Finally, we draw conclusions about the importance of using SDR technologies for ionospheric scintillation monitoring for scientific purposes as well as for operational space weather monitoring.

1217

Areas of Ecological Significance for Southern Ocean nekton

Dr James Grecian¹, Dr Jennifer Freer², Dr Simeon Hill², Prof Richard Phillips², Dr Ryan Reisinger³, Dr Louise Sime², Dr Rahul Sivankutty², Dr Ewan Wakefield¹, Prof Stephen Willis¹, Dr Jose Xavier^2,4, Dr Jie Zhang⁵, Prof Erin McClymont¹

¹Durham University, Durham, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Southampton, Southampton, United Kingdom. ⁴University of Coimbra, Coimbra, Portugal. ⁵Institute of Zoology, Chinese Academy of Sciences, Beijing, China

Abstract

Nekton are the cornerstone of the Southern Ocean ecosystem. They transport and cycle nutrients while also supporting huge populations of marine vertebrates. However, the Southern Ocean ecosystem is changing rapidly, with dramatic reductions in sea ice, and increasing temperatures and winds. This is leading to poleward redistributions and major changes in population sizes of many species. Here, we estimate the environmental niche of 40 nekton species (fish, krill and cephalopods) using an ensemble of four different approaches to species distribution modelling. We develop a new bioregionalization for nekton and identify key biodiversity areas for the nekton community. These are compared with important bioregions identified previously for large marine predators (including whales, seals and seabirds). We explore the extent to which key biodiversity areas for nekton are included in the network of existing and proposed marine protected areas, and where additional protection would be warranted. We then consider the potential redistribution of the nekton community by projecting distributions under two different Shared Socioeconomic Pathways, representing plausible trajectories of societal development at the end of the century. Projected distributional shifts in the nekton community will likely have major implications for nutrient cycling, lead to trophic cascades, and restructure Southern Ocean ecosystems.

1218

Utilising a decade of data to explore the spatial and temporal variability of Antarctic krill around the South Orkney Island archipelago.

Dr Jennifer Freer¹, Dr Victoria Warwick-Evans¹, Dr Georg Skaret², Dr Sophie Fielding¹, Dr Bjorn Krafft², Dr Phillip Trathan¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²Institute of Marine Research, Bergen, Norway

Abstract

Understanding the processes driving the distribution and abundance of Antarctic krill (Euphausia superba) is necessary for implementing a new management framework for the krill fishery. Here, we present a novel distribution model of krill within CCAMLR Statistical Subarea 48.2. The model is the first to utilise a ten-year time series of acoustic transects within an important krill fishing area surrounding the South Orkney Islands archipelago. Such data allow for a dynamic approach to habitat modelling that captures inter-annual environmental variability and facilitates valuable projections of krill density and distribution for years when no survey took place (e.g., 2021).

This presentation will highlight two key findings from the work. First, results show annual krill density to be sensitive to prevailing conditions in the Weddell Sea (sea ice and frontal positions), which in turn vary with Southern Annual Mode. While these linkages have been explored via theoretical models, our results provide novel empirical evidence for their support. Secondly, we show that very high spatial overlap exists between krill hotspots, krill predator foraging areas and fisheries activity. This analysis is an essential element of an ecological risk assessment to identify how to distribute krill catch limits within a new management strategy.

Overall, this paper will contribute i) a novel model for Antarctic krill within the South Orkney Islands and south Scotia Sea, ii) insights into the interactions between climate, oceanography and zooplankton ecology, iii) quantification of human-predator-prey interactions that have implications for ecosystem management and conservation.

1219

The Ellsworth Mountains in the reconstruction of Pangea, Pannotia, and Rodinia

Professor Ian Dalziel, Dr Patricia Dickerson, Dr Staci Loewy

The University of Texas at Austin, Austin, Texas, USA

Abstract

The puzzling physical and geological isolation of the Ellsworth Mountains in West Antarctica was first pointed out by the late James Schopf of The United States Geological Survey in the late 1960s. He suggested on stratigraphic grounds that they had originated along the Transantarctic margin of the East Antarctic craton somewhere north of the Pensacola Mountains. Three separate paleomagnetic studies have confirmed this hypothesis, which is also supported by restoration of the latest Paleozoic Gondwanide fold belt contrary to a recent interpretation of detrital zircon data. Restoration using the fold belt places the Ellsworth-Whitmore (EWM) crustal block of West Antarctica outboard the Coats Land margin of the East Antarctic craton in a reconstruction of the southern, Gondwana, portion of the Phanerozoic supercontinent Pangea. As the Coats Land crustal block of East Antarctica has been identified as a probable detached fragment of Laurentia, the part of the basement of the EWM block exposed in the adjacent Haag Nunataks was also likely of Laurentian origin as supported by lead isotope data. A recent study postulated that identification of a Cryogenian microdiorite in the southern Ellsworth Mountains reflects opening of an ocean basin between the EWM block and Laurentia at that time, a hypothesis that is difficult to reconcile with the position of Laurentia with respect to the South American cratons during the early Paleozoic. An alternative hypothesis is that the microdiorite formed part of the Neoproterozoic rift system in present-day eastern and southern Laurentia. That would mean the EWM formed part of the hypothetical short-lived Pannotia supercontinent combining Laurentia and the newly formed Gondwana at the end of the Precambrian. The basement of the Ellsworth Mountains would have been part of the Grenville-Namaqua-Natal-Maud orogen that sutured Laurentia and the Kalahari craton during the amalgamation of Rodinia at the end of the Mesoproterozoic.

1221

Glacier meltwater transport and pathways along the Beagle Channel

Dr. Jacobo Martin¹, Dr. Jens Meyerjürgens², Dr. Facundo Barrera¹, Dr. Jochen Wollschläger²

¹Laboratory of Oceanography, CADIC-CONICET, Ushuaia, Argentina. ²Institute for Chemistry and Biology of the Marine Environment Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany

Abstract

Global warming is expected to have a more pronounced effect on polar and subpolar regions compared to other areas. In particular, glacier retreat in fjords and other high-latitude estuarine systems will likely result in enhanced freshwater inputs to these areas, with complex implications for ecosystems and hydrodynamics. Changes in meltwater inputs will likely alter vertical stratification and strongly influence surface hydrodynamics, vertical connectivity within the water column, flushing times, and dissolved oxygen concentrations. Furthermore, light availability will also be impacted directly due to high loads of particulate material transported with the meltwater and potentially indirectly by phytoplankton blooms triggered by increased nutrient input. Therefore, understanding the pathways of meltwater in high-latitude regions is essential for assessing impacts on marine ecosystems and hydrodynamics. The Beagle Channel, an interoceanic passage at the southernmost tip of South America, sustains rich and fragile ecosystems that depend on the interplay, distribution, and mixing of marine water masses and continental inputs, including glacier meltwater.

Here, we present a unique dataset of optical and hydrographic measurements along the Beagle Channel extending into the southern Atlantic that can contribute towards an understanding of the fate of the meltwater in this area. Based on optical underway radiometric observations, glacier meltwater could be tracked and the gradients characterized. Backscatter intensity data from moorings can then be used to provide insights into the seasonal variability and the thickness of surface meltwater plumes. The transport of this meltwater along the Beagle Channel will be elucidated by the trajectories of surface drifters and historical current-meter datasets. Data from the Global Drifter Database are used to describe the dispersion and propagation of glacial meltwater in the southern Atlantic Ocean.

1223

13 years of variable height-changes of Gould, Siple, and Shirase coast ice streams from CryoSat-2 altimetry

Dr. Matthew Siegfried¹, Wilson Sauthoff¹, Dr. Dustin Schroeder²

¹Colorado School of Mines, Golden, USA. ²Stanford University, Stanford, USA

Abstract

Observations and modeling over the past decade have shown that ice streams and outlet glaciers in West Antarctica can change on timescales from minutes to millennia, which complicates both the separation of internally driven, dynamic variability from externally forced secular trends and the impact of these changes on ice-freshwater-ocean processes. Current methods for analyzing ice-sheet change from surface-height data rely on the assumption that the time evolution of an ice-sheet surface will follow a prescribed functional form, then leverage additional datasets to identify drivers of change. Here, we apply an alternate method for quantifying and analyzing ice-sheet surface-height variability, where we apply no a priori assumptions for data reduction, then employ spatial statistical methods to identify patterns of change. Using thirteen years (2011-2023) of CryoSat-2 synthetic aperture radar-interferometric mode altimetry data, we investigate over a decade of change at Gould, Siple, and Shirase coast ice streams (Mercer, Whillans, Kamb, Bindschadler, and MacAyeal), identify modes of surface-height variability, and attribute these characteristic spatial patterns of height-change anomalies to potential drivers. We also explore the implications of the surface-height variability we observe on the dynamic subglacial hydrological systems that underlie these ice streams. We suggest that, with spatially dense, temporally continuous, and high spatial resolution (<1 km2) surface height observations from the on-going CryoSat-2 and ICESat-2 missions, statistical methods for height-change analysis, in conjunction of model perturbation experiments, will enable more robust identification of the drivers of ice-sheet change and linked implications for subglacial hydrological and ice-freshwater-ocean processes.

1225

Space Weather Ionospheric Network Canada

Dr Chris Watson¹, Dr Thayyil Jayachandran¹, Dr. Anton Kashcheyev¹, Dr David Themens^2,1, Dr Richard Langley¹, Dr Anthony McCaffrey¹, Dr Torsten Reuschel¹, Dr Karim Meziane¹, Dr Abdelhaq Hamza¹, Dr Alex Koloskov¹, Mr Richard Chadwick¹, Mr Philippe Trottier¹

¹Unversity of New Brunswick, Fredericton, Canada. ²University of Birmingham, Birmingham, United Kingdom

Abstract

Space Weather Ionospheric Network Canada (SWINCan) is a pan-Canadian remote sensing network that provides continuous, real-time ionospheric monitoring spanning polar, auroral, and sub-auroral regions in the northern hemisphere. SWINCan is an expansion and modernization of the Canadian High Arctic Ionospheric Network (CHAIN), operated by the Radio and Space Physics Laboratory (RSPL) at the University of New Brunswick (UNB) and currently one of the world’s largest ionospheric observation networks. SWINCan operates 28 global navigation satellite system (GNSS) scintillation monitors and 10 high frequency (HF) ionosonde sounders for near-real-time ionospheric monitoring, and is currently undergoing a major expansion to 128 GNSS systems and 20 HF sounders by 2026. This expansion includes development of specialized, next-generation modular ionospheric sounder (MODIS) systems to replace current ionosondes, which take advantage of the latest developments in software defined radio and signal processing technology. SWINCan capitalizes on Canada’s geographic expanse and proximity to the northern magnetic pole, which provides a unique natural laboratory for the fundamental study of solar-terrestrial interactions. This network will observe the multi-scale structure and dynamics of the high-latitude ionosphere with unprecedented detail, providing essential measurements to resolve the internal and geospace coupling processes that drive this complex behaviour. Current and future SWINCan stations have magnetic conjugate points spanning the Antarctica Peninsula to the south pole, in close proximity to several Antarctica research stations including GNSS and ionosonde systems. This enables interhemispheric studies of ionospheric structure and dynamics and can provide further insight into the relevant physical processes at play. Details of the SWINCan network and prospective interhemispheric observations will be discussed.

1227

Ice on the Move: What observing the underside of Antarctica’s ice shelves now can tell us about future sea level rise

Dr Peter Washam¹, Dr Britney Schmidt¹, Veronica Hegelein¹, Matthew Meister¹, Dr Frances Bryson¹, Dr Enrica Quartini¹, Daniel Lein¹, Dr Peter Davis², Dr Tore Hatterman³, Dr Keith Nicholss², Dr Craig Stevens⁴, Dr Christina Hulbe⁵, Dr Huw Horgan⁶

¹Cornell University, Ithaca, USA. ²British Antarctic Survey, Cambridge, United Kingdom. ³Norwegian Polar Institute, Tromso, Norway. ⁴NIWA, Wellington, New Zealand. ⁵University of Otago, Dunnedin, New Zealand. ⁶ETH, Zurich, Switzerland

Abstract

Earth’s cryosphere represents one of the fastest changing ecosystems on the planet. Increasing oceanic and atmospheric temperatures are accelerating ice melt and discharge into the ocean, with mass loss from Greenland and Antarctica projected to raise sea level by up to 0.78 meters by 2100. While this projection is dramatic, individual marine-terminating glaciers will contribute to sea level rise differently, as a result of the degree of oceanic and atmospheric forcing they encounter. Focusing strictly on ocean forcing, Earth’s marine-terminating glaciers experience a wide range of melting and freezing regimes that result from the ocean temperature, salinity, current speeds, and pressure. In this talk, we present four years of ice and ocean observations collected in Antarctica with the underwater vehicle Icefin. These cutting-edge observations provide information of how the ice and ocean interact in multiple settings from the warm-based, rapidly-melting and changing Thwaites Glacier to the cold-based, slowly melting and stagnant Kamb Ice Stream, and the variable Fimbul Ice Shelf. The results illuminate a fascinating coupled system where variations in ocean properties interact with small-scale ice slopes to drive melting and freezing over a range of magnitudes. This provides necessary information that can be integrated into models to improve sea level rise projections. I encourage everyone who is curious about this topic to attend my talk. Don’t worry there will be plenty of cool videos!

1228

Quantifying bed elevation uncertainty and mapping out spatial variabilities beneath the Antarctic Ice Sheet

Dr Calvin Shackleton, Dr Kenichi Matsuoka

Norwegian Polar Institute, Tromsø, Norway

Abstract

Constraining bed elevations beneath the Antarctic Ice Sheet is crucial for investigating the subglacial environment as well as estimating current and future ice mass loss. Quantifying uncertainty in contemporary knowledge of subglacial topography can identify key data gaps and could facilitate targeted field surveys. Here, we use geostatistical simulation algorithms to produce bed topography grids with realistic roughness simulated between survey profiles based on nearby measurements. Ensemble analyses of simulated bed at the outlet of Recovery Glacier and near Dome Fuji map out the spatial variability and quantify uncertainty in bed elevations, which is influenced by distance from measurements but also basal roughness. We derived an empirical relationship to suggest survey spacing requirements needed to constrain uncertainty within a specified tolerance level. We upscaled this methodology and simulated bed topography in Dronning Maud Land and are currently simulating an ensemble for the entire Antarctic Ice Sheet margin. Simulated bed facilitates uncertainty-constrained predictions of subglacial phenomena such as water routing, locations of subglacial water outlets, and geothermal heat flow, as well as mapping out and quantifying topographic uncertainty which can help to plan future radar campaigns.

1229

Expressions and importance of Antarctic grounding line pinning

Dr. Lauren Miller¹, Dr. Leigh Stearns², Dr. Kiya Riverman³, Ms. Maya Weiss¹

¹University of Virginia, Charlottesville, USA. ²University of Kansas, Lawrence, USA. ³University of Portland, Portland, USA

Abstract

Mass loss of the Antarctic Ice Sheet is largely caused by changes in the grounding line, the most downstream location where glacial ice contacts with the underlying terrain (i.e., bed) before floating in the ocean. Many processes and conditions at grounding lines and, more expansively, grounding zones are largely unresolved, such as their evolving shape and positionality and controls of such. Specifically, physical bed conditions, such as topography, slope, roughness, and substrate composition, play a role in dictating grounding-line location; yet these properties can vary on spatial scales shorter than glacier catchments. We ask, in lieu of high-resolution data of bed conditions across the continent and using publicly available glaciological data, what empirical observations are associated with or indicative of glacier and ice stream grounding lines and do grounding line conditions indicate different styles of pinning where pinning might exist? We explore the entire contemporary Antarctic grounding line and find that glaciers and ice streams, defined by lateral drag inflection points, occur generally on beds that are less rough than non-glacier and non-ice stream grounding lines. Additionally, the distribution of height-above-buoyancy (HAB) for glaciers and ice streams mirrors that of non-glacier and non-ice stream grounding lines. The majority of glacier and ice stream grounding lines occur on beds between -1200 m and 0 m with HAB values of between 0 m and 40 m; values outside these ranges are statistically considered outliers. We use a variety of metrics to explore potential pinning points and glaciological expressions of pinning at glacier and ice stream grounding lines, finding that observable bed-induced pinning is relatively rare and that retreat from pinning points results in minimal changes to force balance ratios, with implications for the commonality of marine-ice sheet instability.

1230

A review on Pinnipeds’ foraging ecology and their overlap with fisheries in the Western Antarctic Peninsula and Scotia Arc

PhD Renato Borras-Chavez¹, Emily S. Sperou¹, Kevin Lester², Francisco Santa Cruz³, PhD César A. Cárdenas^3,4, PhD Lucas Krüger^3,4

¹Department of Biology, Baylor University, Waco, USA. ²Oceanic Ecology Research Group, Monterey, USA. ³Departamento Científico, Instituto Antártico Chileno, Punta Arenas, Chile. ⁴Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile

Abstract

In recent decades, the krill fishery has increased its spatial and temporal concentration in certain areas of the Western Antarctic Peninsula and the Scotia Arc (Area 48), hence increasing the risk of competition with Southern Ocean pinnipeds (SOPs) feeding predominantly on the same resources. Although we have known the diet of SOPs for decades, our understanding of spatial utilization, foraging behavior, and niche overlap is recent and/or limited. This review accounts for: 1) an update of the current information available on SOPs diet, foraging behavior, and spatial distribution in Area 48, 2) an assessment of the spatiotemporal overlap of SOPs foraging grounds with fishing grounds, 3) principal threats and knowledge gaps that may impact pinniped foraging behavior, and 4) implications for the proposed Marine Protected Area for this sector, known as the Domain 1 MPA (D1MPA). Overall, past and present Antarctic fisheries’ resources account for most of the diet of these pinnipeds, especially krill. We found a significant overlap between fishing hotspots and SOPs foraging areas with a potential functional overlap (e.g. indirect competition) which varied among species. Additionally, evidence suggests that SOPs are responding to changes in krill distribution by expanding their range away from coastal areas and to southern sectors of Area 48.

Furthermore, we discuss important knowledge gaps that limit our ability to accurately evaluate the impact of fisheries on the foraging ecology of SOPs. Shifts of SOPs and fisheries distribution should be addressed during the Harmonisation Process that CCAMLR will conduct this year. Finally, maintaining long-term monitoring of predator populations and incorporating the updated data from this review into the D1MPA proposal is critical to enhance conservation efforts of Southern Ocean Pinnipeds.

1231

Shared values and guiding principles for RINGS Action Group

Dr. Marie Cavitte¹, Dr. Jamin Greenbaum², Prof. Peter Neff³, Dr. Kenichi Matsuoka⁴, Prof. René Forsberg⁵, Dr. Tom Jordan⁶, Dr. Geir Moholdt⁴, Dr. Felicity McCormack⁷, Dr. Kirsty Tinto⁸, Prof. Xiangbin Cui⁹, Dr. Fausto Ferraccioli¹⁰

¹Université catholique de Louvain, Louvain, Belgium. ²Scripps Institution of Oceanography, San Diego, USA. ³University of Minnesota, St. Paul, USA. ⁴Norwegian Polar Institute, Tromsø, Norway. ⁵Technical University of Denmark, Lyngby, Denmark. ⁶British Antarctic Survey, Cambridge, United Kingdom. ⁷Monash University, Clayton, Australia. ⁸University of Columbia Lamont doherty observatory,, Palisades, USA. ⁹Polar Research Institute of China, Shanghai, China. ¹⁰Institute of Oceanography and Applied Geophysics, Trieste, Italy

Abstract

RINGS Action Group facilitates multidisciplinary, international collaborations to fill data gaps in Antarctic Ice Sheet margin mainly using airborne surveys, and to better estimate the Antarctic contribution to global sea-level rise. To foster professionalism within the group, we have developed shared values and guiding principles throughout discussion in two in-person workshops and online discussions (https://scar.org/~documents/route%3A/download/6031). RINGS Action Group has committed to the principles of Equality, Diversity, and Inclusion, ensuring a positive collaborative experience and promoting a sense of community where mutual respect and support are paramount. Upholding these shared values and adhering to the guiding principles serve as primary criteria for project endorsement within RINGS, alongside considerations of scientific significance and relevance. In this presentation, we outline the shared values and guiding principles that define the RINGS Action Group's approach. Additionally, we share our experiences, practices, and lessons learned in fostering professionalism and collaboration within the RINGS Action Group.

1233

Recurrence analysis of Antarctic ice core records at multiple temporal scales

Béatrice Désy¹, Prof Nicholas Golledge², Prof Markus Luczak-Roesch^1,3

¹Victoria University of Wellington, Wellington, New Zealand. ²Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ³Te Pūnaha Matatini Centre for Research Excellence in Complex Systems, Auckland, New Zealand

Abstract

Antarctic ice core records provide invaluable insights about the global climate of the past, in particular about its fluctuations at many different time scales. Yet, many climate models smooth out or average over small scale fluctuations, and there are relatively few methods that bridge the gap between large scale climate patterns and other shorter events. In this talk, I will introduce a new method of interrogating palaeoclimate records based on detecting recurring events of various duration. Events can be any pattern in the time series, and the recurrences are defined using a robust distance measure and a principled statistical test. The output is a network of relationships between moments in time where the record fluctuates in similar ways, which suggests similar underlying processes happening at different epochs and time scales.

Our method is agnostic in the sense that it is does not depend on a model, requires minimal assumptions about the underlying processes that generated the proxy data, and necessitates next to no tuning, interpolating, or binning of the raw time series. This is especially profitable for ice core data, since we can make the most of these rich data despite uneven temporal sampling, and compare different proxies over the same time period. Using it on the EPICA ice core record, we find that it provides unique insights into the natural time scales of recurrences in the global climate system. Furthermore, we use a machine learning algorithm to characterise the type of events that recurs, which paves the way to relating them to underlying physical processes and associated models.

1237

Hemispheric asymmetry in solar wind driving

Dr Stefan Lotz¹, Mr Gellért Le Roux²

¹SANSA, Hermanus, South Africa. ²Stellenbosch Univesity, Stellenbosch, South Africa

Abstract

The coupling between the solar wind and magnetosphere system is complex and its effects are seen at various spatio-temporal scales.

Due to the asymmetric geomagnetic field the reaction to solar wind drivers, and therefore the coupling between the solar wind and the magnetosphere-ionosphere-thermosphere system, is similarly asymmetric.
In order to quantify the assymmetric coupling we utilise methods based in information theory to measure the entropy transfer from the solar wind to the geomagnetic field over a number of events.

Transfer entropy is derived from Granger causality and yields a way to measure the non-linear transfer of information between systems and the associated time lag between the cause and effect. In this paper we present the first result of this kind, based on a large set of solar wind and conjugate geomagnetic field observations. We distinguish between latitude regions, focusing on high latitudes, but showing results from low latitude regions for comparison. Furthermore we show the difference in coupling time signatures for different types of solar wind drivers.

1242

From the Bottom Up: Enhancing Educational Partnerships between Antarctic Emergency Medical Providers and Arctic Security Professionals

Dr. Michele Devlin, Dr. Jose Da Cruz

US Army War College, Carlisle, USA

Abstract

As the southern and northern polar regions warm three or more times faster than anywhere else on earth, geopolitical interest is expanding in both the Arctic and Antarctica. Climate change and new technologies are increasing the number of tourists, scientific researchers, security and emergency response professionals, support personnel, and others in these once remote areas of the world who may be in need of emergency medical care in extreme environments. Antarctica has had a long history of serving as the one of the globe’s premier locations for training personnel involved in disaster response, emergency care, and remote area medicine in extreme cold environments. Ironically, however, many security professionals involved today in military medicine, indigenous circumpolar care, and other health services in the Arctic rarely know of the polar and remote area medical expertise located in Antarctica. This disconnect exists despite the similarities in medical challenges in both polar regions, which can include new epidemiological patterns due to climate change, mental health concerns over isolation, limited availability of tertiary care, low human density, the tyranny of distance, new infectious diseases, and other realities. This presentation discusses opportunities for health organizations to learn mutually from the northern and southern polar regions, build health education and training partnerships between these extreme areas, and enhance the engagement of Arctic public safety and security professionals with their emergency medical response and support unit peers in Antarctica.

1244

Extreme sea surface temperature events in Maxwell Bay: detecting winter Marine Heatwaves and Marine Cold Spells in the last 2 decades.

Octavio Mercado-Peña^1,2, Dr Andrea Piñones^2,3,1,4, Paula Amador-Véliz², Dr José Garcés-Vargas^2,3, Dr Álvaro González-Reyes^3,5, Dr Juan Höfer^3,6, Dr Luis Pardo^2,3, Dr Nelson Valdivia^2,3

¹Centro de Investigación Oceanográfica COPAS-COASTAL, Concepción, Chile. ²Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ³Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ⁴Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago, Chile. ⁵Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, Chile. ⁶Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile

Abstract

The Southern Ocean plays a fundamental role in the uptake and storage of global ocean heat, concentrating between 60 to 90% of heat exchange processes associated with global warming. As it lacks continental barriers like other oceans, atmospherics and oceanic phenomena tend to impact the Antarctic continent more extensively, with the Antarctic Peninsula (AP) being one the most affected areas.

One of the extreme events that have significantly impacted the AP and received increased attention lately is marine heatwaves (MHW), their frequency and duration have experienced a significant increase since the early 20^th century. Although less prominent, marine cold spells (MCS) are also relevant in this context. Both phenomena consist of prolonged periods of low or high sea temperatures anomalies, with evaluation and classification largely based on defining reference thresholds (percentiles 10 and 90, respectively) compared to historical ocean temperature data.

The objective of this study is to quantify and characterize winter MHW and MCS events that have occurred in the last two decades in Maxwell Bay, Antarctic Peninsula. For this purpose, sea surface temperature data from the OSTIA-SST product (0.05°x0.05°) were analyzed, implementing a methodology based on percentile calculations and a 30-year climatology. The results showed a sustained increase in the frequency and duration of MHW, and a significant absence of MCS from the year 2016 onwards. Additionally, a possible relationship was identified between the decrease in sea ice concentration trends and the increase in sea surface temperature trends in the bay during periods consistent with the absence of MCS.

These results provide feedback on what other authors have observed, who have identified changes in sea ice extents since 2015 and trends in ocean temperature in the SO.

1246

Monitoring plankton and hydrography in Potter Cove: observing a changing system during 30 years

Dr Irene R. Schloss^1,2,3, Dr Kerstin Jerosh⁴, Dr Marcelo Hernando⁵, Dr Gastón Almandoz⁶, Ms Julieta Antoni⁶, Ms Gabriela Tosonotto¹, Dr Gustavo Ferreyra²

¹Instituto Antártico Argentino, Buenos Aires, Argentina. ²Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina. ³Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina. ⁴Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ⁵Comisión Nacional de Energía Atómica and CONICET, Buenos Aires, Argentina. ⁶División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina

Abstract

Antarctic ecosystems are experiencing significant environmental changes, leading to shifts in hydrography, plankton abundance, and community composition, potentially affecting the entire food web. Since the early 1990s, the Coastal Ecology Programme of the Argentinian Antarctic Institute, in collaboration with the Alfred Wegener Institute in Bremerhaven, Germany, has been monitoring coastal hydrography and plankton dynamics. Over nearly 30 years, observations at Potter Cove (25 de Mayo/King George Island, South Shetlands) revealed notable transformations, such as the retreat of the surrounding Fourcade Glacier, and its evolution from a tidal to a land-terminated glacier in 2016, coinciding with a consistent rise in temperature. In addition, Potter Cove phytoplankton, characterized by sparse abundances and occasional microphytoplankton blooms during colder seasons in the decades between the early 1990’s and 2010, evidenced a shift occurring post-2010, marked by more frequent and abundant phytoplankton blooms. However, in warmer-than-average years of the last decade, the plankton community composition skewed toward nanosized phytoplankton, including species typical of Subantarctic regions. These findings underscore the necessity for ongoing monitoring and research to comprehend the implications of a warming climate on Antarctic ecosystems. In this sense, in January 2024, as part of the ROMA (Argentinian Network for Observations of Coastal Marine Systems), an automated coastal station was deployed in Potter Cove to gather hydrographic and meteorological data. Similarly, a station with additional sensors for chlorophyll and oxygen concentrations has been operational since 2023 in the Beagle Channel, a Subantarctic coastal area, augmenting our understanding of oceanic changes. During the next year, two Lander moorings will be deployed at 30 m depth in both sites, to collect data on salinity, temperature, dissolved oxygen, chlorophyll, and currents. These initiatives are pivotal for bridging data and knowledge gaps and advancing our comprehension of oceanic shifts.

1247

Coastal Extreme Events: Oceanographic conditions and ocean-atmospheric coupling during Marine Heatwaves in Maxwell Bay, Antarctic Peninsula

Paula Amador-Véliz¹, Dr. Andrea Piñones^1,2,3,4, Octavio Mercado-Peña^3,1, Dr. José Garcés-Vargas^1,2, Dr. Álvaro González-Reyes^5,2, Dr. Juan Höfer^6,2, Dr. Nelson Valdivia^1,2, Dr. Luis Miguel Pardo^1,2

¹Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ²Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ³Centro de Investigación Oceanográfica COPAS-COASTAL, Concepción, Chile. ⁴Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ⁵Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, Chile. ⁶Escuela Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile

Abstract

In recent decades, Antarctica has experienced an increase in extreme climate events with important consequences such as increased sea surface temperature (SST), melting of glaciers and changes in the marine ecosystem. Greatest increases in SST have been recorded during the austral summer, some of them associated with the impact of marine heat waves (MHWs), these events are characterized by being anomalous increases in SST that last for at least 5 days and exceed the reference threshold (90th percentile) constructed with 30 year records. In recent years, a significant increase in the frequency of these MHWs has been observed, which indicates the need for the scientific community to know the implications that these events may have on the water column and how Antarctic ecosystems are threatened.

This study aims to identify the MHWs in Maxwell Bay from 2017 to 2024 based on reanalysis data validated with temperature data at 10 m depth. To study the possible implications on the water column, austral summer CTD observations within the bay and atmospheric conditions were analyzed. Twelve MHW were identified during the austral summer, with 4 of these events corresponding with the oceanographic campaigns carried out during January of each year. Two possible triggering mechanisms were identified, an atmospheric component that would result in a significant increase in temperature in the first 10 m of the water column and another advective component, which would be displacing warm waters, altering hydrographic conditions up to 80 m deep.

The results obtained in this study have implications for the marine ecosystems that inhabit coastal regions, accustomed to relatively small temperature ranges. Our study advances the understanding of the impact of marine heat waves and their effect on coupled interactions between the atmosphere and the ocean.

1252

A new Eocene skeleton from Seymour Island reshapes our understanding of fossil penguin anatomy

Dra. Carolina Acosta Hospitaleche^1,2,3, Lic. María Alejandra Sosa^2,4, Lic. Martín de los Reyes^2,5, Lic. Mauricio Bigurrarena Ojeda²

¹Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ²División Paleontología Vertebrados, Museo de La Plata, La Plata, Argentina. ³Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina. ⁴Universidad Nacional de La Plata, La Plata, Argentina. ⁵Instituto Antártico Argentino, San Martín, Argentina

Abstract

The Seymour/Marambio Island in West Antarctica features an almost complete Tanethian- Bartonian-Rupelian? sequence, renowned for its fossiliferous content. Among vertebrates, penguins are notably abundant and diverse, with fourteen species identified from the Eocene of Antarctica. However, the majority of the known remains consist of disarticulated and isolated bones. Recently, a significant discovery was made, a nearly complete skeleton belonging to a medium sized penguin was found in the uppermost Superior Allomember (Bartonian) of the Submeseta Formation (James Ross Basin) in the locality DPV 13/84. It comprises the complete synsacrum with the pelvis still attached, several ribs, both scapulae, left coracoid, furcula, nine cervical vertebrae, two cervicothoracics, six thoracics, five free caudals, left and right wings (humeri, radii, ulnae, partial carpometacarpi, wing phalanges), left and right legs (femora, patellas, tibiotarsi, tarsometatarsi, fifteen pedal phalanges including three unguals, portions of the mandible with the articular end, bill, quadrate, and other bone fragments, and gastroliths recovered from the synsacrum area. Based on the anatomy of the tarsometatarsus, this specimen could be attributed either to Delphinornis arctowskii or the larger Archaeospheniscus wimani, species only known through their tarsometatarsi. This new specimen represents the most complete fossil penguin skeleton discovered in Antarctica to date, offering a unique opportunity to reassess previous taxonomic assignments based on the size and expected robustness proportions. This newfound skeleton not only enriches our understanding of the skeletal anatomy and paleobiology of Eocene Antarctic species but also challenges preconceptions regarding the size of various skeletal elements.

1254

On the relationship between mesoscale cellular convection and meteorological forcing over the Southern Ocean

Professor Francisco Lang^1,2, Professor Steven Siems², Dr. Yi Huang³, Tahereh Alinejadtabrizi²

¹Universidad de Concepcion, Concepcion, Chile. ²Monash University, Melbourne, Australia. ³The University of Melbourne, Melbourne, Australia

Abstract

Mid- and high-latitude oceans are covered by extensive areas of marine boundary layer clouds. Over the Southern Ocean (SO), these clouds significantly contribute to the regional energy budget. Passive satellite observations have revealed that these clouds are often organized into mesoscale cellular convection (MCC). A convolutional neural network model, utilizing Himawari-8 geostationary satellite observations, identifies two idealized classes of MCC clouds: open and closed. Our analysis shows that open MCC clouds are distributed relatively uniformly over the SO storm track in mid-latitudes, while closed MCC clouds predominantly appear in the Southeast Indian Ocean, with a second concentration along the storm track. The ocean polar front, as derived from ERA5 sea surface temperature gradients, aligns with the southern boundaries of both MCC types. Along the storm track, both types of MCCs commonly occur in post-frontal, cold air masses. The hourly classification of closed MCC reveals a pronounced daily cycle, peaking in the late night to early morning. Seasonally, this diurnal cycle of closed MCC intensifies during the summer months, December through February (DJF). In contrast, open MCC exhibits almost no diurnal variation.

1259

Responses of phytoplankton assemblages to changes in salinity and temperature: a synthesis of the results since 2010

Dr Irene Schloss^1,2,3, Dr Marcelo Hernando⁴, Dr Maité Latorre², Dr Clara Iachetti², Ms Julieta Antoni⁵, Dr Julieta Antacli^6,7, Dr Marleen De Troch⁸, Dr Gastón Almandoz⁵

¹Instituto Antártico Argentino, Buenos Aires, Argentina. ²Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina. ³Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina. ⁴Comisión Nacional de Energía Atómica and CONICET, Buenos Aires, Argentina. ⁵División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina. ⁶Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Ecología Marina, Córdoba, Argentina. ⁷Instituto de Diversidad y Ecología Animal (IDEA - CONICET), Córdoba, Argentina. ⁸Ghent University, Department Biology, Marine Biology, Ghent, Belgium

Abstract

Antarctic ecosystems are undergoing significant changes in environmental conditions, leading to alterations in plankton community composition, which may, in turn, impact the entire food web. In Potter Cove (25 de Mayo/King George Island, South Shetlands), we have conducted hydrography and plankton composition studies for approximately 30 years. These studies involve monitoring changes in phytoplankton assemblages and their responses to changing environmental variables both in situ and through experimental approaches, particularly focusing on seawater temperature and salinity. Over several summer seasons, we conducted multiple sets of microcosm experiments, simulating salinity decreases equivalent to those observed near the coasts affected by glacier melting and water temperature increases of +3 to 4 °C. Here, we present a synthesis of the primary outcomes of over a decade of experimental work. Our results consistently demonstrate that the stress response of organisms, measured through various indicators such as lipid damage and changes in lipid composition, determines the species best adapted under global warming scenarios. In most instances, nanoplankton-sized cells were able to adapt to the stress and dominated phytoplankton assemblages by the end of the experiments. The final composition of the assemblages was highly dependent on the composition at the time of perturbation application. Furthermore, in one experiment conducted in 2016, a temperate species dominated the microcosms where the temperature had been increased. Interestingly, blooms of this species were correlated with high natural temperature summers in the cove's water. In conclusion, our long-term studies in Potter Cove underscore the intricate relationship between changing environmental conditions and plankton community dynamics. These findings highlight the importance of continued monitoring and research efforts to better understand and mitigate the impacts of climate change on Antarctic ecosystems.

1264

Meltwater-driven buoyant upwelling revealed by expendable ocean sensors deployed by helicopter throughout the Thwaites Glacier Tongue, West Antarctica

Dr. Jamin S. Greenbaum¹, Dr. Seung-Tae Yoon², Dr. Jisung Na³, Dr. Clare Eayrs³, Prof. Anna Wåhlin⁴, Dr. Choon-Ki Lee³, Dr. Tyler Pelle¹, Dr. Elizabeth Fine¹, Dr. Matthew Mazloff¹, Prof. Christine Dow⁵, Dr. Sukyoung Yun³, Dr. Won Sang Lee³

¹Scripps Institution of Oceanography, La Jolla, USA. ²Kyungpook National University, Daegu, Korea, Republic of. ³Korea Polar Research Institute, Inchean, Korea, Republic of. ⁴University of Gothenburg, Gothenburg, Sweden. ⁵University of Waterloo, Waterloo, Canada

Abstract

Intrusions of warm ocean water are known to drive melting beneath ice shelves in the Amundsen Sea Sector of the West Antarctic Ice Sheet. However, numerical ocean circulation models are presently unable to reproduce peak melt rates estimated from satellite altimetry missions, a problem currently limiting our ability to accurately predict future glacier retreat. Progress in addressing this discrepancy has been slow due to the difficulty of observing ocean conditions within ice shelf cavities. The collapse of the Thwaites Glacier Tongue (TGT), the western half of Thwaites’ floating ice shelf, resulted in a 1040 square kilometer area separated by full thickness rifts containing mélange of varying thickness. On a series of helicopter flights in early 2022 we discovered areas as small as 10 square meters where only a thin (less than 2 cm) layer of sea ice blocked access to the ocean below. After developing a modified approach for deploying Airborne expendable Conductivity, Temperature, Depth sensors, we acquired eighteen full depth profiles throughout the TGT on helicopter flights in 2022 and 2024. Using these profiles, we show that meltwater-driven upwelling draws otherwise stratified deep warm water into contact with floating ice. We use new model results as evidence that subglacial freshwater enters Thwaites’ cavity in the area where melt rates are highest. We propose that the resulting upwelling contributed to the collapse of the TGT between 2012 and 2016 and has since allowed warm water to drive additional melt inside full thickness rifts, suggesting a positive feedback mechanism inherent to ice shelves overlying warm ocean cavities. Although only direct sampling can definitively discriminate subglacial freshwater from iceberg melt, the new profiles show that subglacial freshwater forcing cannot be ruled out, highlighting a critical uncertainty in our process understanding of Thwaites’ melt and likely other marine-terminating glacier systems.

1265

Shotgun metagenomics reveals microbial biogeochemical cycling in two amictic lakes in the McMurdo Dry Valleys of Antarctica

David Robinson, Jade Lawrence, Dr. Cristina Takacs-Vesbach

University of New Mexico, Albuquerque, USA

Abstract

The lakes of the McMurdo Dry Valleys (MDVs) offer a unique environment to study microbial communities. Perennial ice-cover prevents wind driven mixing and the water columns are chemically and biologically stratified providing stable niches for diverse bacterial populations. However, as temperatures are expected to increase in this region, thinner ice cover and greater hydrologic input could alter the microbial community structure and function of the lakes. We used shotgun metagenomics combined with biogeochemical data to link specific taxa to their functions and identify relationships with their specific physical and chemical drivers. We assembled 431 bacterial metagenome assembled genomes (MAGs) from 31 different phyla across multiple depths in Lakes Bonney and Fryxell. We identified taxonomic and metabolic differences for carbon, nitrogen, and sulfur cycling among the depths and lakes in our study. The patterns of environmental variables and microbial functional diversity illustrate the central role that microbial communities have in the overall productivity of these lakes. Overall, our study shows the need for incorporating microbial metagenomics into the study of MDV lakes, especially with the threat of climate change being expected to alter the physical and chemical drivers of the lakes.

1267

New light on glacial terminations and recoveries ; Multiscale recurring events analysis of Antarctic ice core records

Béatrice Désy¹, Prof Nicholas Golledge², Prof Markus Luczak-Roesch^1,3

Abstract

Seemingly random and abrupt climate transitions might be a fundamental characteristic of most climate systems, as can be observed in many time series obtained from Antarctic ice core and marine sediment records. Yet, the properties of such transitions are seldom captured by traditional climate models, which often smooth out or average over most small scale-fluctuations. In this talk, I introduce a new method of interrogating palaeoclimate records based on detecting recurring climate events. Events can be any pattern in the time series, and the recurrences are defined using a robust distance measure and a principled statistical test. The output is a network of relationships between moments in time where the record fluctuates in similar ways. This suggests similar underlying processes happening at different epochs and time scales, without having to predict and capture them within a model. The applications of our method to the study of regime shifts and abrupt changes are manifold. Namely, when investigating the EPICA ice sheet record with this lens, we can characterise glacials and interglacials in terms of types of events at various scales, which is different from observing the same physical system operating at a different average temperature. We also study agnostic signatures of early warning signals and recovery from an abrupt change in terms of the average time that separate recurring events, independently of the nature or shape of these events. Our approach is complementary to other data-driven early warning signals in that it looks at the global properties of the time series without having to reduce it to its statistical properties.

1268

Exploring hydrographic properties around the South Shetland Islands: Insights from Pinniped Sensors.

Ms. Natalia Cisternas¹, Dra. Andrea Piñones^2,3,4,5, Dr. Oscar Pizarro^6,7, Dr. Manuel Castillo¹, Dr. Christian Reiss⁸, Dr. Douglas Krause⁸

¹University of Valaparaiso, Valparaiso, Chile. ²Austral University of Southern Chile, Valdivia, Chile. ³IDEAL Center, Valdivia, Chile. ⁴COPAS COASTAL, Concepcion, Chile. ⁵Millennium Institute BASE, Santiago, Chile. ⁶Department of Geophysics, University of Concepcion, Concepcion, Chile. ⁷Millennium Institute of Oceanography, Concepcion, Chile. ⁸Antarctic Ecosystem Research Division, Southwest Fisheries Science Center (NOAA), La Jolla, USA

Abstract

The South Shetland Islands (SSI) constitute a highly productive area, characterized by uneven bathymetry and temporal variations in sea ice concentration. Combined with inputs of water from the Weddell Sea, Bellingshausen Sea, Drake Passage, Bransfield Strait, and Gerlache Strait, the combination of these water masses characteristics lend the region its fcomplexity. The main objective of this research was to analyze the temporal and spatial variability of hydrographic conditions in the vicinity of the SSI, along with identifying their primary drivers. To conduct this analysis, data collected from CTD-SRDL attached to Weddell seals and leopard seals as part of the AMLR program were utilized.

The spatial distribution of observations revealed four regions where the dive data was concentrated. Thermohaline properties and changes in different water masses in the study area were analyzed within each of these regions. To interpret this variability, sea ice concentration was also analyzed using satellite information and reanalysis data, along with wind data and in-situ atmospheric temperature from the meteorological stations at the Chilean bases Eduardo Frei and Arturo Prat.

The results showed that intra-seasonal variability in hydrographic conditions was mainly associated with the dives of pinnipeds and particularly focused on the north and south of Livingston Island. During winter, sea ice concentration emerged as a dominant factor in the dynamics of both ocean temperature and salinity. Additionally, during fall, atmospheric temperature correlates better with changes in ocean temperature. Interannual variability was also observed, associated with the Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO).

Finally, the conditions analyzed emphasized the importance of understanding the physical processes of the ocean, where sea ice plays a crucial role in the dynamics of this Antarctic coastal ecosystem inhabited by pinnipeds.

1270

The international PAGINA project to realise the Pan-Arctic GNSS INfrastructure for Atmospheric and Space Weather Science

Dr. Vincenzo Romano¹, Dr. Claudio Cesaroni¹, Prof. Thayyil Jayachandran², Dr. Krsti Kauristie³, Dr Sara Mainella¹, Dr. Carlo Marcocci¹, Dr. Emanuele Pica¹, Dr. Luca Spogli¹, Dr. Massimo Viola¹

¹Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy. ²University of New Brunswick, Fredericton, Canada. ³Finnish Meteorological Institute, Helsinki, Finland

Abstract

The PAGINA (Pan-Arctic GNSS INfrastructure for Atmospheric Science) project is funded by the Italian Arctic program. PAGINA aims to fill the existing gap of observing GNSS systems and related ICT platforms over the Arctic region by gathering the GNSS information acquired at Svalbard, Finland, Greenland, and Canada. The unprecedented effort represents the unique infrastructure capable of monitoring and investigating the northern polar atmosphere utilizing high-rate GNSS data. The novelty stands in the integration of different data sources managed by INGV (Svalbard and Greenland), UNB (Canada) and FMI (Finland), creating a bi-continental infrastructure. The e-infrastructure will be based on the existing eSWua (electronic Space Weather upper atmosphere) data management system to facilitate the data management and accessibility in an FAIR approach. eSWua ia a data infrastructure working since 2006 also with Antarctic data. PAGINA is a case study as international scientific collaboration can bring advantage in building common infrastructure for data sharing for the scientific and industrial community for space weather applications. In this paper we will present the state of the art of the PAGINA project, its perspectives and future development. The paper wants also to stimulate the discussion on potential collaboration on space weather studies and infrastructures for polar regions.

1272

Ecophysiological responses of Antarctic vascular plants to in situ and controlled laboratory warming conditions.

Dr. León Bravo¹, Dr. Dariel López¹, Dr. Olman Gómez¹, Valentina Vallejos^1,2, Dr. Patricia Sáez^1,3, Dr. Lohengrin Cavieres^2,3

¹Universidad de La Frontera, Temuco, Chile. ²Universidad de Concepción, Concepción, Chile. ³Instituto de Ecología y Biodiversidad, Concepción, Chile

Abstract

Regional warming in the Antarctic Peninsula has been identified as the second fastest globally. This area boasts the highest biological diversity in Antarctica, making it crucial to understand the effects of warming on its biosphere. The colonization of Maritime Antarctic by two vascular plant species, Deschampsia antarctica and Colobanthus quitensis, underscores the significance of studying the consequences of warming on these unique plant species. Warming not only directly affects temperature but also leads to increased evapotranspiration, a factor yet to be adequately addressed in Antarctica. Higher temperatures induce changes in leaf morphology, promoting plant growth and reproduction. However, this may result in heightened vulnerability to severe stress events. To investigate this hypothesis, we compared plants exposed to warming using open top chambers (OTC) near Arctowski Station and conducted controlled laboratory experiments. Plants subjected to warming exhibited increased growth and reproductive traits, although there was a trend towards reduced freezing tolerance it is not enough to jeopardize plant survival. Additionally, warming plants displayed enhanced thermal stability and dehydration tolerances. Laboratory experiments revealed a stronger response to nocturnal warming than diurnal warming, with reduced expression of cold acclimation genes. This is consistent with the asymmetric warming predicted by climatic models.

In the field, both diurnal and nocturnal warming only slightly increased vulnerability to stochastic frosts, although freezing tolerance remained below the lowest temperatures experienced before snow cover. Evidence is inconclusive regarding the vulnerability of Antarctic plants to warming. Despite promoting growth and population expansion, warming has not rendered these plants vulnerable, assuming snow coverage continues to provide protection, but late snow fall, or earlier snow thawing may compromise these species if nocturnal warming promotes cold deacclimation in these plant species.

Acknowledgments: Fondecyt1201824; INACH FR 02_20; INACH RT-18_18; Fondecyt 1211231; ACT 210038.

1273

Turbulent fluxes in the austral summers of 2020/2021 and 2021/2022 on Penguin Island, Antarctica.

Dr Marcelo Santini¹, Dr Luciano Pezzi¹, Dr Celina Rodrigues¹, Dr Mylene Cabrera¹, Dr Luciana Lima¹, Tiffany Mendonça¹, MSc Dayanis Montero¹, MSc Gabriel Münchow²

¹National Institute for Space Research, São José dos Campos, Brazil. ²Rio Grande do Norte Federal University, Natal, Brazil

Abstract

The polar regions are considered the most vulnerable area in the world due to climate change. This fact motivates continuous data sampling to monitor the environmental changes occurring in this climate system. A micrometeorological tower was installed in the austral summers of 2020/2021 and 2021/2022 to measure turbulent fluxes on Penguin Island, in a region overlooking the Bransfield Strait. This tower provides a better understanding of the interaction processes between the coastal surface and the atmospheric boundary layer in the South Shetland Islands region. In addition to the turbulent fluxes of latent and sensible heat, momentum, and CO2, atmospheric variables such as wind speed and direction, air temperature, relative humidity, atmospheric pressure and incident solar radiation were also collected. The highest average magnitudes of sensible and latent heat fluxes were observed in the summer of 2021/2022 when compared to the summer of 2020/2021. Sensible heat fluxes varied on average between 1.9 and 1.2 W/m² and latent heat fluxes varied between 35.7 and 22.3 W/m². The CO2 flux was dominantly negative in the two summers sampled, acting on average more intensely in the first summer (-5.2 μmol/m².s) when compared to the second period (-4.4 μmol/m².s). These results are very important, as in addition to quantifying the exchanges between the surface and the atmosphere, they allow us to produce information needed to verify numerical simulations for this region.

1277

QIceRadar: A Tool for Accessing and Visualizing Georeferenced Radargrams in QGIS

Laura Lindzey

University of Washington Applied Physics Laboratory, Seattle, USA

Abstract

QIceRadar is a NSF-funded project that aims to make ice penetrating radar data more FAIR (Findable, Accessible, Interoperable, Reusable). Currently, it is challenging to access the wealth of airborne ice penetrating radar data that has been collected over Antarctica. These valuable surveys have been performed by independent teams of scientists, using bespoke and constantly evolving radar systems. The resulting radargrams are stored across many national data centers and are released using often-incompatible data formats. As a result, there is significant technical effort required for a researcher to simply locate, download and view these data, providing a barrier to their use.

QIceRadar attempts to lower this barrier by developing tools compatible with the open-source QGIS ecosystem. QGIS is already broadly used by the polar research community, thanks in part to the popularity of the Quantarctica and QGreenland data compilations. First, we improve findability by providing an index of known radar transects as a geopackage database, offering drag-and-drop compatibility with QGIS. Next, we improve interoperability via a QGIS plugin that works in concert with the database to assist researchers in downloading available radargrams and then viewing them in geographical context. QIceRadar supports radargram formats used by major field programs that have publicly released their data (including BAS, CReSIS, and UTIG) along with a handful of formats used by smaller surveys. These tools will be publicly released in August 2024, and we look forward to community feedback.

We present the motivation for developing QIceRadar and demonstrate its functionality, followed by an overview of the current state of Antarctic data coverage and radargram availability. We also discuss features of data repositories that contribute to data accesibility for tools like this, as well as how radargram data formats impact often-requested features in QIceRadar.

1278

Investigating the dynamics of kelp-associated bacterial microbiomes in Antarctic and subantarctic environments

Dr Phoebe Chapman, Professor Ceridwen Fraser

Department of Marine Science, University of Otago, Dunedin, New Zealand

Abstract

Host-associated microbiomes (i.e. the community of microbes living on or within a given organism), play crucial roles in shaping physiological processes within their host organisms, influencing immunity, metabolism, and growth. In marine ecosystems, these microbial communities are particularly exposed to environmental influences, with changing climates and extreme weather events potentially driving shifts in microbial community composition.

While Antarctica has long been considered isolated, kelp rafts originating from populations further north are known to reach Antarctic shores. Despite the inability of permanent kelp populations to establish in Antarctic environments thus far, climate change may facilitate colonisation in the future. The successful establishment of kelp populations in Antarctica hinges not only on the suitability of local climatic conditions, but also on the persistence or adaptation of their microbiomes, without which the health of the plant is likely to deteriorate.

Our study aims to characterise and compare the bacterial microbiomes associated with macroalgae (Durvillaea antarctica and Macrocystis pyrifera) across various sites throughout the Southern Ocean. Through the collection of kelp swab and tissue samples from subantarctic islands and Antarctia, we seek to compare and track bacterial community composition between these sites using 16S amplicon sequencing and host genomics. Additionally, we will determine the influence of the environment on kelp microbiomes using concurrently collected environmental samples. By doing so, we aim to provide insights into the stability of bacterial communities associated with kelp and the potential for kelp rafts to transport or adapt their microbial communities for new locations.

Our findings hold significance for understanding potential future changes in Antarctic ecosystems resulting from climate change and shed light on the mechanisms underlying microbial community dynamics in marine environments.

1279

Dental specializations of Antarctodon sobrali (Mammalia, Astrapotheria) from the Eocene of West Antarctica: proxies of paleoenvironmental and phylogenetic inferences

Dr. Javier N. Gelfo^1,2,3, Dr. Guillermo López^2,3

¹CONICET, La Plata, Argentina. ²División Paleontología de Vertebrados, Museo de La Plata, La Plata, Argentina. ³Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina

Abstract

Today, the lack of land vertebrates in Antarctica is linked to limited liquid water availability and a biome with insufficient primary productivity to sustain these communities. However, warmer climates during the Late Cretaceous and early Eocene, combined with the Antarctic Peninsula's terrestrial connection to South America and Australia, enabled significant vegetation cover, facilitating the development of diverse communities of terrestrial birds and mammals. Notably, Paleogene levels of La Meseta and Submeseta formations on Seymour (Marambio) Island in the James Ross Basin have yielded significant assemblages of terrestrial vertebrates. The Eocene fossil record from these formations showcases the apex of the West Weddellian Biogeographic Province in Antarctica. It predates the complete extinction of land vertebrates on the continent, which resulted from widespread deterioration of terrestrial ecosystems, possibly induced by climate changes associated with tectonic events such as the final Gondwana break-up. The Paleogene land mammals of West Antarctica exhibit a rich diversity, featuring marsupials and placentals with affinities with those from the Paleogene from South America. Among them are larger species ranging from 50 kg to half a ton, including Sparnotheriodontidae and Astrapotheria ungulates. New dental specimens recovered from the lower coquina levels of the Cucullaea I Allomember within the La Meseta Formation (Telm 4) and found at DPV 2/84 and IAA 2/16 localities, shed light on several aspects of the lower dentition of the endemic Antarctic Astrapotheria, Antarctodon sobrali. Main features such as brachyodonty, vertical Hunter-Schreger bands, reinforcement of enamel thickness, and postvallid columns below the protolophid indicate specialized browsing adaptations, consistent with the fossil record of dense Nothofagus-Araucaria type forests. An entoconid changes through different loci, from a postentolophid to a truly "notoungulate" transverse entoconid in the last molar. This character suggests a close phylogenetic affinity with Trigonostylopidae astrapotheres, previously interpreted as a paraphyletic group.

1282

Filling the Gaps: The ISOBatA Project's Approach to Underway Bathymetric Surveying in Antarctic Research

Ms. Daniela Accettella¹, Dr. Marco Cuffaro², Dr. Paolo Diviacco¹, Prof. Alessandra Savini³, Dr. Fabrizio Zgur¹, G. M. Ferrante¹

¹OGS - National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ²CNR-IGAG National Research Council of Italy, Rome, Italy. ³Milano Bicocca University - Dept. Of Earth and Environmental Sciences (DISAT), Milan, Italy

Abstract

In an era of rapid climate change, the comprehension of the Antarctic ice sheet dynamics is critical to understanding sea level rise and oceanographic phenomena. Despite the compelling need for detailed bathymetric data for these studies, only 25% of the ocean seafloor has been mapped so far. Based on the experience of the ISOBatA project, supported by the Italian National Antarctic Research Program (PNRA), we offer a glimpse into the potential and challenges of optimized underway bathymetric data acquisition during Antarctic expeditions.

The principal aim of the ISOBatA project was to collect bathymetric and magnetometric data along the transit routes of the Italian icebreaker Laura Bassi, focusing on previously unsurveyed regions. Using existing metadata, including the International Bathymetric Chart of the Southern Ocean (IBCSO), Italian core area sites, and seismic SDL (Seismic Data Library) lines, we strategically selected areas of scientific interest. This approach not only maximized the efficiency of data acquisition but also fostered collaboration and knowledge sharing between research initiatives. By allocating project-dedicated time to reduce speed and navigate along specific routes, the project significantly enhanced the quantity, quality, and scientific value of the dataset.

Our findings show a variety of geomorphic processes that contribute to shape the seafloor in the Southern Ocean. Among others, submarine landforms created by ice-seafloor interactions that formed curvilinear and spiral-like incisions are widespread on the shelves, indicating the effect of tidal and geostrophic currents in driving icebergs' drift.

Even though data is sometimes collected under less-than-optimal conditions, due to operational constraints, high ship speed, and/or unfavorable weather conditions, strategic data collection while underway remains crucial. An improved understanding of the Southern Ocean and its evolution in the context of global climate impacts depends on the critical role of international collaborative efforts, including the sharing of strategies and practices.

1287

The Climate Feedback Loop: Amino Acid Metabolism's Effect on GHG Emissions in Antarctic Soils

Dr Carolina Merino

Universidad de La Frontera, Temuco, Chile

Abstract

Global warming accelerates the microbial decomposition of soil organic matter (SOM) in Antarctic ecosystems, highlighting the need to better understand its implications on greenhouse gas (GHG) emissions including CO₂, N₂O, and CH₄. These gases contribute to global warming in a positive feedback loop. However, current estimates of the magnitude and form of these emissions present significant uncertainties, partly due to the oversimplified representation of geochemical constraints on microbial decomposition in biogeochemical models. This study investigates how amino acid metabolism influences GHG emissions in soils of King George Island's Fildes Peninsula, particularly in areas recently exposed by the retreat of the Collins and Nelson glaciers (0 to 50 years post-retreat). We hypothesize that microbial activities driven by redox conditions and physicochemical parameters regulate GHG emissions through amino acid catabolism and anabolism. The methodology used includes soil sampling throughout chronosequences, microcosm experiments with oxygen fluctuations (oxic-anoxic-redox conditions), stable isotope analysis, X-ray diffraction, and Mössbauer spectrometry, in addition to microbial sequencing to correlate soil physical properties and GHG. The results showed that GHG emissions increased significantly in soils with higher aromatic amino acid breakdown (oxygen >5%). N₂O emissions margins (13.1 to 40.3 μg N₂O g⁻¹ soil) are linked to nitrification and denitrification activity, with higher levels observed at sites with significant amounts of aliphatic amino acids and anoxic conditions at glacier. CH₄ emissions (24.6 to 64.5 μg CH₄ g⁻¹ soil) were highest in areas with high water saturation, while CO₂ emissions were uniformly distributed but increased with temperature and the availability of labile substrates near the coast. Stable isotopes indicated that aromatic and aliphatic amino acid catabolism considerably increased the substrate pool for N₂O and CH₄ generation. The findings demonstrate that amino acid metabolism by soil microorganisms is an important driver of GHG emissions in Antarctic soils under redox conditions influence biogeochemical cycles.

1288

Cryptic paths of Gondwana-forming collisional orogenic belts revealed in East Antarctica

Fausto Ferraccioli^1,2, Graeme Eagles³, Bruce Eglington⁴, Joachim Jacobs⁵, Guochao Wu⁶, Joerg Ebbing⁷, Rene Forsberg⁸, Tom Jordan², Alexander Golynsky⁹, Chris Green¹⁰

¹National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ²NERC/British Antarctic Survey, Cambridge, United Kingdom. ³Alfred Wegener Institute, Bremerhaven, Germany. ⁴University of Saskatchewan, Saskatoon, Canada. ⁵University of Bergen, Department of Earth Science, Bergen, Norway. ⁶Second Institute of Oceanography, Hangzhou, China. ⁷Christian-Albrechts-Universität Kiel, Kiel, Germany. ⁸echnical University of Denmark, Lyngby, Denmark. ⁹VNIIO, St Petersburg, Russian Federation. ¹⁰University of Leeds, School Earth and Environment, Leeds, United Kingdom

Abstract

East Antarctica is the least understood continent involved in the assembly of Gondwana, a key stage in the global supercontinent cycle. Seismological and gravity imaging reveal thick crust stretching from Dronning Maud Land to the Gamburtsev Subglacial Mountains. Major crustal thickening is interpreted here as associated with the collision of India and East Antarctica during Gondwana assembly. Geological and geophysical research has revealed key aspects of the collisional East African-Antarctic Orogen. However, the paths of other orogens such as the Kuunga Orogen in the ice sheet covered interior of East Antarctica have remained difficult to investigate, making it particularly challenging to understand the processes leading to Gondwana assembly.

Here we present a new satellite-conformed aeromagnetic anomaly compilation that includes data collected between the interior of Dronning Maud Land and South Pole, together with airborne and satellite gravity imaging and seismological and geological constraints that provide tantalising new views into different crustal provinces, cratons and orogens in interior East Antarctica. We propose that a suture zone, partially exposed in the Shackleton Range, crosses the continent linking to major fault systems in the Gamburtsev Province and potentially in Princess Elisabeth Land.

We suggest that accretion of continental ribbons, accreted island arc superterranes and several microcontinents need to be considered in addition to the larger Australo-Antarctic, Indo-Antarctic and Afro-Antarctic continents, when attempting to disentangle the processes of Gondwana assembly in East Antarctica from Edicaran to Cambrian times.

1289

Assessing long-term warming impacts on Antarctic soil microbial communities and exploring the microbiome transplantation for ecological restoration.

Dr. Kattia Núñez-Montero¹, Prof David Madariaga-Troncoso¹, Prof León Bravo²

¹Universidad Autónoma de Chile, Temuco, Chile. ²Universidad de La Frontera, Temuco, Chile

Abstract

The Antarctic ecosystem, characterized by its extreme conditions and vulnerability to climate change, provides a unique and invaluable model for studying the impacts of global warming on terrestrial ecosystems. Utilizing this pristine environment to investigate the effects of long-term simulated warming on soil microbial communities offers unparalleled insights into the fundamental processes driving ecosystem responses to climate change. Given the global significance of soil ecosystems in regulating climate, water cycles, and biodiversity, understanding and preserving the integrity of these systems in the face of climate change is paramount. Therefore, in response to the urgent need for sustainable management strategies to combat the effects of climate change on soil ecosystems, our research project, investigates the impact of increased temperatures on the microbial communities within Antarctic soils and explores the innovative approach of microbiome transplantation as a remediation strategy. Using in situ Open-Top Chambers (OTCs) to simulate long-term warming conditions, our study has successfully characterized the alterations in microbial communities over periods of 5 and 10 years of exposure to increased temperatures, revealing significant shifts in microbial composition due to elevated temperatures. These findings underscore the sensitivity of soil microbial ecosystems to climate change and highlight the potential for long-lasting impacts on soil health and ecosystem services. Building on these insights, our project has pioneered developing and evaluating a microbiome transplantation protocol to restore the disturbed soil microbiomes to their original, unperturbed states. This approach offers a novel method for mitigating the adverse effects of climate change on soil ecosystems and provides a model for enhancing soil resilience and function through targeted microbial interventions. We hope that this Antarctic model contributes to our knowledge of polar soil ecosystems and informs global efforts towards sustainable environmental management and climate change mitigation.

1290

Antarctica as a Space Analogue - Utilising Opportunities in Remote Practice to Inform in the Space Domain

Dr Jonathon Lowe^1,2, Dr Matthew Warner¹

¹British Antarctic Survey Medical Unit, Plymouth, United Kingdom. ²Academic Department of Military Emergency Medicine, Birmingham, United Kingdom

Abstract

The provision of healthcare across the Antarctic continent offers a unique opportunity to inform how we may be required to deliver healthcare during prolonged space missions.

Given the nature of Antarctica, operating at extreme reach in what can be described as a resource poor environment, is a direct parallel to providing healthcare in space when we consider the limitations to payload, options for evacuation and timelines to receiving care back on Earth.

In order to better understand this parallel and the lessons it may teach us, the authors have started to enhance the level of care they can provide remotely through a number of means, not limited to telemedicine and the potential for augmented reality - enabling UK clinicians a providers view of clinical cases and directly overseeing procedures in realtime. This enables those with different training backgrounds to support deployed clinicians as well as providing expert advice without needing to deploy forward. It may also permit the holding of patients at reach for greater periods, again simulating a prolonged space mission without scope to return to Earth immediately.

Other lessons are being learnt with the forward deployment of novel equipment. When considering a limited capacity for medical payload being sent on any space mission, the rationalisation of medical equipment carried into the deep field is allowing the authors to understand where changes can be made that provide both safety as well as capacity for the carriage of other resources. This is a development on previously presented work looking at modernising deployed healthcare capabilities and healthcare infrastructure.

The utilisation of Antarctica for research and training should always consider the parallels that can be drawn between space and aviation medicine - particularly when analysing medical risk, capabilities at reach and forward deployment of equipment.

1291

Can we really use design-free hydroacoustic data from fishing vessels as a cat’s paw to assess Antarctic krill abundance and distribution off the South Orkney Islands?

Dr. Jose Antonio Canseco Rodriguez¹, Dr. Edwin Niklitschek², Dr. Georg Skart³

¹Instituto Español de Oceanografia, Cadiz, Spain. ²I~mar, Puerto Montt, Chile. ³Institute of Marine Research, Bergen, Norway

Abstract

Euphausia superba is an Antarctic species of great economic and ecological importance whose management requires accurate and precise abundance and distribution estimates. Such estimates are difficult to achieve given the remoteness, wide distribution and large spatio-temporal variability of the krill. Acoustic data collected on board krill fishing vessels during normal fishing operation has a great potential to enhance such abundance and distribution estimates. In the present work we hypothesize that design-free hydroacoustic data collected during regular fishing operations can be used to produce abundance and distribution estimates with similar accuracy and precision than design-based scientific surveys. We produced and compared distribution and abundance estimates produced using either design-free hydroacoustic data collected during regular fishing operations or design-based data from scientific surveys conducted off the South Orkney Islands during summer 2017 and 2019. Following a Bayesian geostatistical We tested different auto-correlation structures and selected the most informative models following a Bayesian geostatistical approach. The comparison included the means and coefficients of variation of the probability of presence, conditional density and relative abundance index estimates. In 2017, the mean RAI estimated using design-free data (94 421 m²; CV: 14%) were ~50% higher than the estimated with design-based data (60 232 m²; CV: 42%), both within the fishing area. In 2019, mean RAI estimated using design-free data (509 413 m² CV: 6%) was ~5-fold higher than the one obtained using design-based data (113 654 m²; CV: 33%) in the same area. Design-free RAI estimates were highly sensitive to extrapolating the inference area from fishing to the high-density sub-area. Despite observed differences in mean estimates, both methods identified similar areas of high presence and density of E. superba north and north-west of the South Orkney Islands. The 2017 estimate from design-free data was probably affected by a larger dispersion of krill, and a less observed effective area during regular fishing operations. Bias and uncertainty related to design-free data were reduced when parallel or orthogonal transects were applied although orthogonal transects yielded results with increased accuracy as they were only 21% lower and 0.02% higher than the true value in 2017 and 2019, respectively. Our results show that despite using state-of-the-art methods for processing and analyzing design-free, acoustic data collected by the fishing fleet, it still yielded unreliable RAI estimates making a design-based approach necessary.

1297

Intrinsic value in Antarctica: three case studies to explore the challenges

Dr Rupert Summerson

Independent scholar, Canberra, Australia

Abstract

Despite the flaws in the Madrid Protocol and the apparent lack of interest from Antarctic Treaty Consultative Parties in implementing its provisions, it remains the best hope for protecting the Antarctic environment. High in the list of its provisions (Article 3) is the protection of the intrinsic value of Antarctica, which should be “a fundamental consideration in the planning and conduct of all activities in the Antarctic Treaty area”. Protection of the intrinsic value is coupled with the protection of the wilderness and aesthetic values, which are conventionally considered as anthropocentric instrumental values but can, I believe, be demonstrated to be equally well considered as intrinsic values. Aesthetic judgements are disinterested judgments (sensu Kant) and cannot therefore be instrumental. Given that wilderness is the antithesis of human presence, it is an appropriate candidate for intrinsic value, on condition that the wilderness is protected for its own sake, not for instrumental reasons.

Intrinsic value is however a difficult and controversial concept. The idea that nature should be valued for itself flies in the face of human self-belief. Ultimately however, nature is often only really valued when it is under threat. In order to test how the intrinsic values of Antarctica could be protected, three case studies will be presented: the Lemaire Channel in the Antarctic Peninsula, the Vestfold Hills in eastern Antarctica and the sea ice zone. The protection of the intrinsic value of each presents its own challenges. The Lemaire Channel is very popular with tourists, the Vestfold Hills has a history of over 60 years of human activities and impacts and the sea ice zone is under threat from climate change. By examining how these can be valued intrinsically, the protection of the intrinsic value of Antarctica can hopefully be advanced.

1299

Airborne mapping of South Pole Basin and the southern Gambertsev Subglacial mountains from an old ice perspective: results of the COLDEX airborne program.

Duncan Young¹, John Paden², Megan Kerr¹, Shivangini Singh¹, Shravan Kaundinya², Shuai Yan¹, Alejandra Vega González^3,4, Jamin Greenbaum⁵, Dillon Buhl¹, Gregory Ng¹, Michelle Koutnik⁶, TJ Fudge⁶, Nicholas Holschuh⁷, Thomas Richter¹, Scott Kempf¹, Donald Blankenship¹, Edward Brook⁸

¹University of Texas Institute for Geophysics, Austin, USA. ²University of Kansas, Lawrence, USA. ³University of Puerto Rico Mayagüez, Mayagüez, USA. ⁴University of Virginia, Charlottesville, USA. ⁵Scripps Institute for Oceanography, Austin, USA. ⁶University of Washington, Seattle, USA. ⁷Amherst University, Amherst, USA. ⁸Oregon State University, Corvallis, USA

Abstract

The Center for Oldest Ice Exploration (COLDEX) is a US initiative funded to search for climate records over the last 5 million years, including locating sites for an accessible continuous ice core going back 1.5 million years. As part of this effort, COLDEX has mapped the southern flank of Dome A, East Antarctica using an instrumented Basler, including dual frequency radar observations of the ice sheet and ice bed, as well as potential fields measurements across two field seasons. The system included both the UTIG VHF MARFA radar system operating at 52.5-67.5 MHz, as well as a new large UHF array from CReSIS operating at 687.5-747.5 MHz MHz. One result of this was a survey explicitly designed around ice sheet flow lines. While prior work had sampled the region at lithospheric scales, the COLDEX survey had two components - the first was to map the region at crustal scales, and the second was to map subareas at ice sheet scales. Immediate observations include an extensive basal unit and strong discontinuity in englacial stratigraphy that runs across the survey area and appears correlated with changes in bed interface properties. The airborne campaign will be used to inform follow up ground campaigns to understand processes relevant for old ice preservation.

1301

Evidence of amino acids preference by iron(III)-reducing bacterial communities on iron oxide minerals after the glacier retreated in sub-Antarctic areas

Dr Carolina Merino¹, Dr Ignacio Jofre¹, Dr Francisco Najera¹, Dr Michaela Dippold²

¹universidad de La Frontera, Temuco, Chile. ²Universitat Tuebingen, Tuebingen, Germany

Abstract

First-stage glacial retreat soils are rich in iron (Fe) oxides. Ferrihydrite, goethite, hematite, and magnetite are iron oxides that preferentially generate ferrous iron (Fe(II)) without oxygen. In emerging ecosystems, iron cycling and microorganism respiration depend on this reduction mechanism. Different degrees of crystallinity of iron oxides may indicate their functions in soil genesis and geochemical development. To partially oxidize soil organic carbon (SOC) for catabolic processes, our study suggests that microbes prefer to reduce poorly crystalline iron oxide phases rather than their crystalline counterparts. Crystalline Fe oxides obtain terminal electrons, allowing anaerobic bacteria to thrive in low-nutrient settings. Our hypothesis was that Fe(III)-reducing bacteria (IRB) catabolism of anaerobic carbon and amino acids is controlled by the reduction of more crystalline minerals in early soil development after glacial retreat. We catalyzed dissolved organic carbon (DOC) oxidation in microcosm liquid incubations at 5 °C under controlled anaerobic conditions. Adding isolate IRB from polar and subpolar soils to amorphous and crystalline Fe oxides and 18 L-amino acids. We measured CO₂, Fe(II), and microbial cell development. At the start and end of incubation, we measure amino acid consumption. Iron-reducing bacteria increased sterilized soil CO₂ emissions, with magnetite enrichments producing twice as much CO2 as ferrihydrite. Similar emissions from goethite and hematite. The greatest increase in Fe(II) production was 362% in magnetite with tyrosine. Our findings indicate that Geobacter spp. preferentially use aromatic amino acids for anabolic growth and utilize DOC catabolism for energy, with iron reduction playing a critical role in both processes. These microbes' intricate utilization of resources shows their adaptation to the Sub-Antarctic's changing environment

1303

A role for exercising in Antarctica: a report of Brazilian Human biology research

Dra. Michele Moraes¹, MS Ygor Martins², MS Mateus Rumão³, MS Nathalia Garcia⁴, Gabriel Santana², Dr. Thiago Mendes^2,3,4, Dra. Rosa Arantes¹

¹Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ²Postgraduate Program in Medicine and Health, Universidade Federal da Bahia, Salvador, Brazil. ³Postgraduate Program in Science and Health, Universidade Federal do Maranhão, São Luis, Brazil. ⁴Postgraduate Program Physical Education, Universidade Federal do Maranhão, São Luis, Brazil

Abstract

Fieldwork in Antarctica's natural environment imposes moderate to high-intensity physical demand while different isolated, confined, and extreme (ICE) conditions of permanence in Antarctica (camps, ships, and stations) can affect hormonal axes, metabolic systems, sleep pattern regulation, and neurocognition. Exercise is an intervention that can improve the aerobic capacity for coping with physical effort and has the potential to mitigate some of the psychophysiological adverse effects of ICE. Herein, we summarize our results from almost a decade of Medicine and Human Physiology research in Antarctica and our perspective on performance and physical training in this context. For the camps, we highlight the 'training effect' through fieldwork for individuals with the lowest initial aerobic capacity in the groups, with increases to values close to 40 mlO₂.kg^-1.min^-1 (i.e., between ‘fair’ and 'good') lasts until the expedition's return. Compared to a camp, the total displacement in a day is up 70% lower on the ship (1.16±0.36km/day); thus, physical exercise can contribute to an active routine. On two expeditions where we conducted physical training on the ship, we observed improvements in aerobic fitness, body composition, cardiac autonomic control, and cognitive performance in the training group. Furthermore, physical exercise can be a strategy to minimize changes during the period on board. We also highlight an initial experience of our group with monitoring the activity pattern by actigraphy over a year with individuals wintering in a research station, which will contribute to understanding the times in which the physical exercise intervention could be further relevant to avoid sedentary behaviour. Therefore, physical training has emerged as a central topic of MEDIANTAR's interest once it is one of the most prominent interventions to promote health benefits during an expedition to Antarctic ICE and beyond.

Funded by CNPq/MCTI/CAPES/FNDCT/PROANTAR: [442645/2018-0] and [440932/2023-8]; and CNPq/MCTI [408740/2023-0].

1308

Beneath Thin Ice: Evaluating the Influence of Contrasting Sea Ice Dynamics on Coastal Planktonic Communities Using Desalination Plant Filters

Dr. Matteo Cecchetto^1,2, Prof. Isabella Moro³, Ms. Valentina Cometti^2,4, Mrs. Marco Grillo^2,4, Dr. Diego Fontaneto⁵, Prof. Gentile Francesco Ficetola⁶, Dr. Sanghee Kim⁷, Dr. Young Wook Ko⁷, Prof. Stefano Schiaparelli^1,2

¹Department of Earth, Environmental and Life Science, University of Genoa, Genoa, Italy. ²Italian National Antarctic Museum, University of Genoa, Genoa, Italy. ³Department of Biology, University of Padova, Padova, Italy. ⁴Department of Physical Sciences, Earth, and Environment, University of Siena, Siena, Italy. ⁵Water Research Institute, National Research Council of Italy, Verbania Pallanza, Italy. ⁶Dipartimento di Scienze e Politiche Ambientali, University of Milan, Milan, Italy. ⁷Department of Polar Life Sciences, Korea Polar Research Institute, Incheon, Korea, Republic of

Abstract

Altered sea ice dynamics are expected to be one of the most important factors influencing future biological communities in the Southern Ocean. This is particularly true for the Antarctic plankton, whose composition is characterized by an intrinsic extreme dynamism, highly linked to the seasonal fluctuations of the sea ice. In order to unravel the consequences of changing sea ice dynamics, frequent sampling activities need to be adopted with the concurrent shift of planktonic communities, often occurring within weeks or days. However, the unfavourable weather conditions that can be experienced in Antarctica pose a well-known challenge to the application of such biological monitoring investigations.

Here we show the usefulness of desalination plants as monitoring tools to assess the diversity and community succession of coastal planktonic communities under varying sea ice conditions. We present a case study investigating the succession of planktonic communities during two austral summers showing different sea ice dynamics (2018-2019 and 2021-2022). Molecular data were extracted from the 25 µm filters of the desalination plant operating at Mario Zucchelli Italian research station (Ross Sea), with an average sampling frequency of 3 days, from November to February of each summer. The seawater facing the intake pipe of the desalination plant experienced contrasting dynamics in the two years due to the unusually late break-up and drifting of the sea ice observed in the 2021-2022 period. Nonetheless, the desalination plant continuously operated in both years, thus recording the development of communities facing these different conditions.

By taking advantage of built-in logistic desalination facilities and standardizable molecular techniques, this sampling methodology allows us to overcome the difficulties of standard sampling procedures and provide a clear spectrum of the influence that the seasonal advance and retreat of sea ice, including its trend and extreme events, has on coastal planktonic communities.

1310

Subantarctic conservation success : what’s the science telling us?

Dr Justine Shaw

Securing Antarctica’s Environmental, QUT Future, Brisbane, Australia

Abstract

Subantarctic islands are some of the last true wilderness on the planet. Home to many threatened species, endemic species and aggregations of hundreds of thousands seabirds and seals. Most of the islands are World Heritage Areas that have fascinated scientists for decades. With such high conservation value it is critical we manage these islands effectively. We explore how are faring, what has the science taught us about our conservation efforts to date ?

We examine invasive species impacts, subsequent management and quantify the response across the region. We examine threatened species population trajectories and review current management.

We synthesis conservation science across the region and identify how science informing this. We identify areas for further research and management action

1313

Antarctic snow algae - physiology and diversity

Dr Matthew Davey

SAMS, Oban, United Kingdom

Abstract

Snow algae are found in snowfields across cold regions of the planet, forming highly visible red and green patches below and on the snow surface. In Antarctica, they contribute significantly to terrestrial net primary productivity due to the paucity of land plants, but our knowledge of these communities is limited. Here we provide descriptions of the metabolic and species diversity of green and red snow algae communities from southern (Rothera, Ryder Bay) and northern (South Shetland Islands) locations along the Antarctic Peninsula during our field work from 2014 to the present day at Robert Island. Green communities were protein‐rich, had a high chlorophyll content and contained many metabolites associated with nitrogen and amino acid metabolism. Red communities had a higher carotenoid content and contained more metabolites associated with carbohydrate and fatty acid metabolism. We will also present information on the photosynthetic and respiration rates these snow algae communities produce over a season (NCER net carbon exchange rate, ER ecosystem respiration, GEP gross ecosystem photosynthesis) using gas exchange IRGA techniques, and how these values compare to rates in other nearby moss and grass species. We will discuss logistics of sampling and data collection in remote regions for metabolomic studies and our current phylogenetic and morphological analysis of new isolates. These data show the complexity and variation within snow algae communities in Antarctica and provide valuable insights into the contribution they make to ecosystem functioning. (Davey et al 2019, Grey et al 2020, 2021) https://snowalgae.org/.

1314

Italian Marine Observatory in the Ross Sea – MORSea

PhD Pasquale Castagno¹, Professor Pierpaolo Falco², Professor Yuri Cotroneo³, Leonardo Langone⁴, Professor Giorgio Budillon³

¹University of Messina, Messina, Italy. ²Marche Polytechnic University, Ancona, Italy. ³University of Napoli Parthenope, Napoli, Italy. ⁴Institute of Polar Sciences - National Council of Research (CNR-ISP), Bologna, Italy

Abstract

The Ross Sea is a crucial region for the Earth's climate, contributing to about 25% of the Antarctic Bottom Water (AABW), originating from Dense Shelf Water (DSW) produced on the continental shelf. Changes in the properties of the AABW affect the global ocean, influencing stratification, sea level, heat content, and the carbon cycle. Understanding the long-term variability in the physical properties of the Ross Sea DSW and its controlling factors is crucial for assessing AABW fluctuations. Recent studies show significant changes in oceanographic parameters, ice cover, and biogeochemical processes in the Ross Sea. The Marine Observatory in the Ross Sea (MORSea), funded by the Italian National Antarctic Research Program (PNRA) since 2009, has a network of five moorings in the western Ross Sea that have been active since 1995. Two moorings are located in the Terra Nova Bay polynya, where the DSW forms, and three are located near the shelf break in the Drygalski, Joides, and Glomar Challenger basins, where the exchange with the open ocean water occurs. Since 1995, MORSea has collected a 30-year time series of temperature, salinity, and ocean current measurements. Besides instruments used to measure the physical properties of the ocean, MORSea moorings are also equipped with sediment traps to estimate the annual and interannual variability of vertical particle fluxes. In addition, the moorings were also used as platforms for passive and active acoustic in-situ monitoring of biological activities. An echo sounder was installed to study zooplankton, while passive acoustic monitoring instruments were deployed to observe marine mammals. Since 1995, MORSea also includes ship-of-opportunity activities such as XBTs and thermosalinograph temperature and salinity measurements along the New Zealand-Antarctic 'chokepoint' of the Antarctic Circumpolar Current. In collaboration with ARGO-ITALY, the observatory has also deployed floats and drifters in the Southern Ocean and the Ross Sea.

1315

DNA Barcode Completeness of Antarctic Eukaryotes: a Broad Assessment for the Identification of Knowledge Gaps

Dr. Matteo Cecchetto^1,2, Mis. Alice Guzzi^1,2, Prof. Stefano Schiaparelli^1,2

¹Department of Earth, Environmental and Life Science, University of Genoa, Genoa, Italy. ²Italian National Antarctic Museum, University of Genoa, Genoa, Italy

Abstract

The Southern Ocean and Continental Antarctica are characterized by a unique biota that adapted to millions of years of peculiar environmental conditions. The ongoing climatic changes, occurring within human timeframes, are expected to induce major shifts in these biological communities, compelling the adoption of advanced technologies, such as High Throughput Sequencing, allowing rapid and accurate assessments. However, their application is hindered by a variety of constraints, the foremost being the limited DNA Barcode completeness, i.e. the representativeness of species on public DNA repositories. The recent application of such technologies in Antarctica, coupled with the lack of exhaustive biodiversity data, enhances this issue, prompting the need for a thorough evaluation of knowledge gaps.

Here, we present the first assessment of DNA barcode completeness for Antarctic eukaryotes, quantifying the gap between species occurrences and genetic information availability. This is performed for both the terrestrial and marine environments, through data mining of taxonomic names assembled from the Register of Antarctic Species and the Global Biodiversity Information Facility, on the major public repositories of genetic sequences, such as the National Center for Biotechnology Information and the Barcode of Life Data Systems. The results are presented for all major eukaryotes taxa and the most frequently adopted genetic markers (i.e. COI, 18S, and ITS). A special focus on Metazoa reveals the existence of discrepancies in the barcode completeness of different taxa, with major groups still being overlooked. The limited representativeness of Antarctic species on public DNA repositories is further evidenced by the usefulness of small national biological collections, providing a higher percentage of publicly unrepresented species.

The ability to quantify the gap between biodiversity species lists and DNA sequence availability allows for a proper definition of future research priorities and provides a baseline for monitoring future invasive species through DNA techniques.

1320

Design and Deployments of Antarctic Submersible ROV Icefin for Subglacial Observations and Mapping

Matthew Meister, Dr. Frances Bryson, Daniel Lein, Dr. Peter Washam, Dr. Enrica Quartini, Veronica Hegelein, Jorge Coppin-Massanet, Dr. Britney Schmidt

Cornell University, Ithaca, USA

Abstract

Technological advancements have led to an increase of the ability to map Antarctica and understand the properties and movement of ice sheets from airborne surveys. Underneath the ice, however, we can glean even more insight into the processes happening beneath the glaciers, as well as the biology that exists in these remote locations. To this purpose, we developed Icefin, a remotely or autonomously operated vehicle (ROV/AUV), to be deployed through boreholes in Antarctica. Icefin is designed to be modular and portable to enable remote field deployments, as well as operate in the extreme environment of low temperatures, extreme depth, and unknown terrain. Its modularity allows it to carry a variety of science packages, including a custom water sampler, a custom instrument for measuring frazil ice, and a mapping sonar that can be used facing either the seafloor or ice surface to create a bathymetric map from under the ice. Communicating through a 4.5 km fiber optic tether, operators can see live data from the vehicle, including oceanographic measurements such as conductivity, temperature, pressure, and dissolved oxygen; as well as live sonar and camera imagery. As it is remotely operated, this information can be used to investigate areas of high interest, such as finding glacier grounding lines, probing the ice-ocean interface, or even capturing imagery of wildlife. Since its beginning in 2014, Icefin has been refined into a capable and reliable platform for science, and completed more than 50 dives in Antarctica, including deployments on the Ross Ice Shelf, Thwaites Glacier, and the Fimbul Ice Shelf. We present here the current design - the fourth revision - of Icefin, how it is deployed, and how its design enables sensing and mapping in remote areas underneath glaciers in Antarctica.

1324

Mud pellets in sediment cores from beneath the Ross Ice Shelf: markers of subglacial drainage and grounding line retreat.

Ms Linda Balfoort, Dr Gavin Dunbar, Dr Cliff Atkins

Victoria University of Wellington, Wellington, New Zealand

Abstract

Mud pellets have been described from glaciomarine sediments in several locations around the world. However, their genesis remains enigmatic because the processes that creates the pellets has not been physically observed. Here, we describe mud pellets from the HWD-2b core recovered from beneath the Ross Ice Shelf in Antarctica. Based on our core data and published literature, we consider the processes likely involved in their formation and provide a sedimentation model in the context of ice shelf retreat. The pellets occur within massive mud and interbedded sands and muds overlying consolidated subglacial diamictite. They comprise small (~1-5 mm) subrounded clasts with blocky to ellipsoidal form. The pellets are soft, low-density, structureless sandy mud, and display a distinct primary grainsize mode at ~3µm, and a subordinate mode at ~110µm.

The regional distribution of the mud pellet deposits is patchy but observed in several cores recovered from underneath the ice shelf. In the context of sub glacial and ice shelf environments, we suggest that initial mud deposition occurred within subglacial lakes at the ice-bed interface where fine sediment is able to settle out of suspension. Mud pellets are then produced by episodes of rip-up erosion and entrainment of consolidated mud beds where flows exceed 0.16m s-1, followed by rapid redeposition. This could occur either through channelised sub-glacial drainage events or by tidal currents or tidal pumping as the grounding line retreats over the mud deposits, accounting for their stratigraphic occurrence overlying subglacial diamictite. The patchiness of mud pellet occurrence in the Ross Sea may reflect highly localised and intermittent reworking of subglacial lake sediments. Further analysis of mud pellets may provide useful insights for interpreting and constraining sub glacial and grounding line sedimentation.

1325

Art Diplomacy for Antarctica

Mr John Weller

Only One, New York, USA

Abstract

As darkness filled a cold February night in the heart of Moscow, 8-foot-high photographs of Antarctica stood illuminated, stretching nearly 100m down the walkways of Tverskoy Boulevard, two kilometers from the Kremlin. The exhibition showcased the work of John Weller, Paul Nicklen, Cristina Mittermeier, and an early-career photographer from Moscow. Interpretive panels highlighted the history of Russian involvement in the Antarctic, climate change, natural history, and the rationale for marine protected areas. The illuminated images were so beautiful, so powerful, and so out of place that they stopped almost every passerby in their tracks.

There is something in those stark landscapes and profound creatures that crosses language and culture. It cuts clean through to a childlike wonder of the world, and leaves the heart and mind open to a story. A toddler with wide eyes in her father’s arms pointed a grey woolen glove at an image of Adelie penguins climbing a graceful curve of ice. A group of teenage girls looked at a whole exhibit, pulling each other along from image to image and giggling amongst themselves. Some visitors went around twice, reading everything and studying the photographs in silence. Some came back again the next day. Tverskoy Boulevard is one of the most popular places for walking in Moscow. The exhibition was be seen by more than 200,000 people from February 8 to March 8, 2020.

Recounting anecdotes from 20 years of using art to bring the story of the Antarctica and the Southern Ocean to audiences across the globe, John Weller will illustrate from his experiences the critical importance of photography, writing and filmmaking in building a global audience for Antarctica and Antarctic science, and in building diplomatic bridges that result in progress.

1329

Microbial Secondary Metabolites along Natural Gradients: Sentinels of Environmental Change in an Antarctic polar desert

Jill Mikucki¹, Lesley Ann Giddings², Jacob Shaffer¹, Robert Samples², Riko Mukoyama², Ross Virginia³

¹University of Tennessee, Knoxville, USA. ²Smith College, Northampton, USA. ³Dartmouth College, Hanover, USA

Abstract

The Antarctic McMurdo Dry Valleys (MDV) are poised for change due to climate warming. In the MDV, hydrologic connectivity, mediated by meltwater dynamics originating either from glacier or lake ice, permafrost, or snow patch melting, drives distinct gradients of moisture, salinity, and other geochemical parameters in soils, streams and lakes. These gradients can alter the expression of biosynthetic genes involved in microbial metabolism. Because the MDV experiences limited anthropogenic inputs and hosts natural geochemical gradients, it is an ideal site for studying the natural abundance, accumulation, and ecological functions of microbial secondary metabolites. Secondary metabolites are small, structurally diverse, organic molecules produced by microorganisms in response to ecological stimuli that help microorganisms navigate change. The specific role of these metabolites in an ecological context are poorly understood, thus elucidating these functions could provide more rapid molecular indicators of changing ecosystems than shifts in community structure alone. For example, increasing the biosynthesis of osmoprotectants, such as ectoine, may help manage pH and salt stress and increasing antibiotic production may enable microbes to better compete for changes in nutrient availability. Using direct measurements, comparative genomics (metagenomics and metatranscriptomics), and metabolomics we can determine the genetic underpinnings of secondary metabolite production and then validate the production of specific metabolites under changing conditions. Here we report progress towards characterizing microbial secondary metabolism in the MDV using both archived natural samples and microcosms prepared with ecologically relevant isolates grown under varied in situ geochemical conditions. We observe distinct metabolite responses to environmental stressors such as pH, solar radiation salinity and nutrients. The overarching goal is to exploit microbial chemical fingerprints as an ecological “gauge” that rapidly monitors microbial community response to changing environmental conditions.

1334

The Antarctic Society: The Nested Nature of South America’s Antarctic Identity

Dr Ignacio Cardone, Dr Nicolás Terradas

Pontifical Catholic University of Peru, Lima, Peru

Abstract

The idea of the Antarctic peninsula as an extension of the American continent has been proposed since the early 20th century, first as the “Antártida Americana” and later as the “Antártida Sudamericana,” promoting a sense of connection and belonging. Originally promoted by Argentina and Chile, this idea progressively gained traction in other South American countries and is still powerful today, albeit not entirely uncontested. Through a reinterpretation of the concept of international society employed by the English School of International Relations, this paper develops the idea of "nested societies" as a multiplicity of superposed societies and advances the idea of a South American "Antarctic Society" as a historical political construction that has combined with other international societies. Through a historical inquiry, the paper first traces the constitution of a complex of nested international societies in which the South American “Antarctic Society” is inserted, and then describes its development through the use of primary sources. In conclusion, the paper suggests that the concept of nested societies is valuable for analyzing a complex of international identities and that a South American "Antarctic society" was constituted through a long and complicated historical process that articulated its interaction with other international societies, thus revealing that what the Antarctic politics literature has typically framed as contradictory dynamics are actually the result of the nested nature of a complex of international identities.

1336

The Role of the Meeting of Administrators of Latin-American Antarctic Programmes (RAPAL) in institutionalising South-America cooperation in Antarctica

Dr Ignacio Cardone

Pontifical Catholic University of Peru, Lima, Peru

Abstract

South-American cooperation in Antarctica dates back to the early 20th century, and was institutionalised in the “Reunión de Administradores de Programas Antárticos Lationamericanos” (RAPAL), preceding the creation of the Council of Managers of National Antarctic Programs (COMNAP). However, the actual impact of RAPAL on promoting coordination and cooperation in South-American Antarctic operations remains unclear. Drawing on archival material and interviews, this paper seeks to assess the actual impacts of RAPAL, the institutional mechanisms facilitating cooperation, and the main assets and obstacles for South-America Antarctic cooperation, both generally and within RAPAL specifically. To date, our findings suggest that RAPAL has been successful in establishing coordination mechanisms and rationalizing resources beyond what individual parties could have achieved independently. In addition, RAPAL has facilitated the exchange of best practices and served as a forum for discussing pertinent issues among South-American partners. On the other hand, RAPAL has lacked a more fixed institutional structure and has been susceptible to domestic political circumstances that hindered its effectiveness.

1339

Life History and Foraging Efficiency: Implications for breeding success in Wandering Albatrosses on Marion Island

Ms Danielle Keys^1,2, Dr Chris Oosthuizen^2,3, Prof. Peter Ryan⁴, Prof. Pierre Pistorius^1,2

¹DST/NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Institute for Coastal and Marine Research, Nelson Mandela University, Gqeberha, South Africa. ²Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Gqeberha, South Africa. ³Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa. ⁴FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa

Abstract

Seabirds are long-lived species that face trade-offs between growth, survival, somatic maintenance, and reproduction. When foraging conditions are poor in adverse environmental conditions, many adult seabirds prioritize their own survival over that of their offspring, resulting in lowered breeding success rates. Changes in seabird breeding success thus can help us understand how environmental conditions and life-history constraints will influence population dynamics. Our study focused on the Wandering albatross (Diomedea exulans) from Marion Island, investigating how changes in foraging efficiency (i.e., foraging behaviour and foraging performance) affect breeding success at both individual and population levels. We combined data from daily observations during incubation and chick rearing over three breeding seasons (2007 – 2009) with fine-scale GPS tracking data (1998, 2009, 2013, 2014, 2016 – 2021; seasons n = 10). This allowed us to estimate foraging trip duration from colony observations as well as assess foraging behaviour and performance (i.e., foraging trip duration, mean and maximum distance travelled, flight speed, and home range) using GPS data. Using Generalized Linear Mixed-Effects Models, we evaluated the impact of foraging efficiency on hatching success, brood success, and fledging success of chicks. Interestingly, the foraging trip duration did not impact the success of the individual chicks, but years with longer average foraging trips correlated with lower population breeding success rates. Additionally, when birds spent less time resting and commuting at sea, and more time foraging, they had higher breeding success rates. However, we found little additional evidence indicating that other factors significantly influenced breeding success. By unravelling the complex relationship between foraging efficiency and breeding success, our study enhances our understanding of how a long-lived species' responses shape its population dynamics. Addressing underlying environmental factors is crucial in combating the decline in breeding success of this species.

1340

Optimising UAS protocols for Vegetation Monitoring in Antarctica: Key Insights and Case Studies from the Windmill Islands, and Bunger Hills

Juan Sandino^1,2, Matthew Swan³, Julian Galvez-Serna², Narmilan Amarasingam^1,2, Ashray Doshi⁴, Krystal Randall^4,5, Sharon A. Robinson^4,5, Barbara Bollard^4,5, Felipe Gonzalez^1,2

¹Securing Antarctica's Environmental Future, QUT, Brisbane City, Australia. ²QUT Centre for Robotics, QUT, Brisbane City, Australia. ³Research Engineering Facility, QUT, Brisbane City, Australia. ⁴Securing Antarctica's Environmental Future, UoW, Wollongong, Australia. ⁵School of Earth, Atmospheric and Life Sciences, UoW, Wollongong, Australia

Abstract

Monitoring vegetation in Antarctica requires innovative approaches that outperform traditional field methods for precise environmental monitoring. In this presentation, we will showcase the use of unmanned aerial systems (UAS) for ecological surveys of Antarctic vegetation in the Windmill Islands and Bunger Hills in East Antarctica. We have optimised UAS protocols and integrated advanced remote sensing techniques with artificial intelligence (AI) to process complex drone imagery.

Antarctica's vegetation, including moss, lichen, and cyanobacteria, serves as a key indicator of environmental change and presents unique challenges for conservation and research due to its sensitivity to climate variability. To address these challenges, we have developed a scalable workflow that leverages the precision of drones equipped with multispectral and hyperspectral sensors. This approach enables us to generate detailed, high-resolution vegetation maps, facilitating accurate assessments of their distribution.

Our study shows the effectiveness of AI models in improving vegetation mapping accuracy using UAS data. By leveraging custom spectral indices and derived features from key wavelengths (404, 480, 560, 655, 678, 740, 888, and 920 nm), our models achieve detection accuracies exceeding 85% for moss and lichen. This approach can be scaled up with satellite imagery for macro-scale analyses, providing an alternative to traditional mapping techniques. Moreover, our method minimises the need for comprehensive ground truth data, addressing the challenges of accessibility and environmental impact in Antarctic locations, in particular, for vegetation mapping in Bunger Hills. This workflow not only enhances the accuracy of vegetation maps but also ensures minimal disturbance to the environment during field practices.

1347

License to krill: an AI biogeophysical model to forecast krill in the Antarctic Peninsula.

Mr Danilo Astorga^1,2, Mr Octavio Mercado², Miss Yanara Morgunovsky^1,2, Mr Cristian Cofré^3,4, Ms Matilde Rivas^5,6, Mr Dantes Arduam⁷

¹Instituto de Ciencias Marinas y Limnologicas, UACh, Valdivia, Chile. ²Laboratorio de Procesos Acoplados Biofísicos, Valdivia, Chile. ³Instituto de Ciencias Fisicas y Matematicas UACh, Valdivia, Chile. ⁴Instituto de Informática, UACh, Valdivia, Chile. ⁵Instituto Milenio Fundamentos de los Datos, Valdivia, Chile. ⁶Universidad de Chile, santiago, Chile. ⁷Universidad Austral de Chile, Valdivia, Chile

Abstract

Recently awarded with the second place in the 8th Ocean Hackaton in France, this interdisciplinary study seeks to predict the population dynamics of Antarctic krill (Euphausia superba) in the Antarctic Peninsula. An artificial intelligence model based was developed using standardized sampling from KRILLBASE, bathymetry and projected environmental data. The model was elaborated based on machine learning models such as vector machine, Radon forest regression and XGbost. The environmental data was obtained from Copernicus marine service and includes monthly sea surface temperature, salinity, chlorophyll-a, and kinetic energy for the summer months. The environmental data was obtained from Copernicus Marine Service from December to February (Austral Summer). The abundance and distribution of the krill sampling and environmental factors were used as input files to train the AI model. Finally, the AI model was run with the SSP585 scenario from CMIP6, forecasting the distribution and abundance of krill over the Antarctic Peninsula. This information was finally deployed on a web interface overlayed with management units for an easy understanding and use of the information. The final model explained 0.59 of the variability of Krill on the Antarctic Peninsula,with a combination of Sea Surface Temperature and chlorophyll-a as main predictors. While these are promising results, this predictive AI model is still in development and can be further improved by acquiring more data and processing power. This is one of the firsts developed application of Artificial Intelligence models forecasting krill behaviour in Antarctica, providing insights of the benefits and challenges of applying this new technology in Antarctic studies.

1348

Siliceous microfossil response to the Cretaceous-Paleogene extinction event: the influence of volcanism and meteorite impact on the Seymour Island biostratigraphic record

Jason Coenen¹, David Harwood¹, Thomas Tobin²

¹University of Nebraska-Lincoln, Lincoln, NE, USA. ²The University of Alabama, Tuscaloosa, AL, USA

Abstract

The Cretaceous-Paleogene (K-Pg) boundary is well known because of the catastrophic mass extinction event that impacted climate and biological diversity. Seymour Island, located at the northeastern tip of the Antarctic Peninsula, includes outcrops of Maastrichtian to Danian marine strata that contain rich and diverse fossil records. Previous work highlighted this site as an important area for studying detailed records of K-Pg evolution and extinction of siliceous microfossils. With recent observations highlighting the potential influence of Deccan volcanism in addition to the meteorite impact driving extinctions, it is essential to examine this section to understand how the polar oceans responded during this significant event in Earth’s history. To better understand the response of siliceous communities to these events, material from the Polar Rock Repository(OSU) and Burke Museum(UW) were analyzed.

We present a record of siliceous microfossils and their response to previously identified geochemical events from two intervals at Seymour Island. Interval 1 is ~70 meters below the K-Pg (~150 ka before), and Interval 2 is near the transition from the Lopez de Bertendo Formation to the Sobral Formation. Interval 1 highlights a response in the marine diatom community with increased resting spore abundance at the inferred end of a pulse of Deccan volcanism ~40 m below the K-Pg. Interval 1 highlights the influence Deccan volcanism or change in surface water nutrient availability from local sources may have had on nutrients for siliceous communities and their response in this high-latitude marine shelf setting. Interval 2 following the K-Pg highlights the survival of most diatom taxa with minimal loss of marine diatom taxa. Diatom resting spores increase in dominance above the K-Pg and occur with a unique silicoflagellate assemblage, suggesting an environmental perturbation at the transition to the Sobral Formation. Future work will increase sample resolution to resolve these responses further.

1351

Unlocking the Potential of Polar Orbiting Satellites: The Impact on Polar Observation and Mapping by the Reference Elevation Model of Antarctica (REMA) and the Polar Geospatial Center (PGC)

Cathleen Torres Parisian, Cole Kelleher, Kelsey Zimmerman

Polar Geospatial Center, University of Minnesota, St. Paul, USA

Abstract

Polar orbiting satellites have revolutionized our ability to observe and map the Antarctic environment, particularly through initiatives managed by the Polar Geospatial Center (PGC). The collaboration between the PGC, U.S. National Geospatial-Intelligence Agency (NGA), the U.S. National Science Foundation (NSF), and other institutions have facilitated the generation of high-resolution digital surface models (DSMs) for polar regions, including the Reference Elevation Model of Antarctica (REMA). These products leverage commercial optical satellite imagery, advanced photogrammetry software, and high-performance computing to provide continental wide, time-dependent elevation data with unprecedented detail. Additionally, the absence of aircraft requirements simplifies data collection in remote and high-latitude areas.

The REMA dataset offers comprehensive coverage, enabling researchers to observe and measure topographic changes over time, may provide corrections for a wide range of remote sensing processing activities, such image orthorectification and interferometry, and provide constraints for geodynamic and ice flow modeling, mapping of grounding lines, and surface processes. REMA also provides a powerful new resource for field logistics planning. Strengths of this initiative includes the use of multiple polar-orbiting satellites, automation, and high-performance computing, allowing for rapid and extensive terrain generation available for free to the public through 2032.

However, challenges persist, including the presence of clouds and shadows, and limited accuracy without ground control points. Despite these limitations, the DEM products provide invaluable insights into the Antarctic environment and serve as critical resources for a wide range of scientific and environmental applications.

Moving forward, continued advancements in remote sensing technologies and data processing techniques promise to enhance the utility and accuracy of satellite surveys, furthering our understanding of the dynamic Antarctic landscape and its responses to environmental changes. This talk will highlight the significant improvements in data quality, production methodology, temporal availability, and outlook for future REMA improvements and releases.

1352

Intra- and interspecific transfer of microplastics by feeding and predation in seabirds of the Fildes Peninsula, King George/25 de Mayo Island, Antarctica

Dr. Franco Teixeira de Mello¹, Barbara De Feo¹, Evelyn Krojmal¹, Dr. Juan Pablo Lozoya¹, Gissell Lacerot¹, Anja Russ², Dr. Christina Braun²

¹Centro Universitario Regional del Este (CURE), Universidad de la República, Maldonado, Uruguay. ²nstitute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Str. 159, 07743, Jena, Germany

Abstract

Plastic pollution is a global issue affecting marine-coastal systems worldwide, including remote areas like Antarctica, where the presence of plastics and microplastics (MPs, <5 mm) resulting from human activities has been documented both on the continent and in the surrounding sea. Aquatic fauna are vulnerable to this pollution, experiencing various negative interactions, such as ingestion, often due to confusion with their prey. Observations indicate that surface-feeding seabirds, like procellarids (e.g., petrels), ingest and accumulate more plastic waste than those feeding underwater. Moreover, there is evidence of MPs being transferred to their chicks during feeding. In Antarctica, brown skuas (Stercorarius antarcticus lonnbergi) have been observed preying on various species of Procellariiforms, suggesting the potential transfer of MPs through predation. This study aimed to assess the consumption and transfer of MPs from three petrel species (Oceanites oceanicus, Fregetta sp., and Pachyptila sp.) to brown skuas, as well as the subsequent transfer of MPs to O. oceanicus chicks. Skua pellets were collected near identified nests at Fildes Peninsula, while dead chicks were opportunistically collected at Potter Peninsula. Analysis of skua pellets containing identifiable petrel species and the stomach contents of chicks revealed that 31% of the pellets contained primary MPs fragments of various colours and shapes. The pellets containing O. oceanicus as prey had the highest MPs concentration, primarily polyethylene and polypropylene. Furthermore, 89% of chicks analyzed contained MPs, with the accumulation of MPs increasing as the chicks matured. These findings underscore the different pathways through which MPs are transferred within seabird communities, highlighting their exposure and vulnerability to this type of pollution in Antarctica.

1356

Genomics windows into the diversity adaptations and evolution of Antarctic life.

Professor Alison Murray¹, Professor Rauri Bowie², Dr. Patrick Chain³, Professor Allyson Hindle⁴, Dr. Bin Hu³, Professor Rachael Morgan-Kiss⁵, Professor Rachel O'Neill⁶, Professor Tatiana Rynearson⁷, Professor Oscar Schofield⁸, Professor Arvind Varsani⁹, Professor Jill Wegrzyn⁶

¹DRI, Reno, USA. ²University of California, Berkeley, Berkeley, USA. ³Los Alamos National Laboratory, Los Alamos, USA. ⁴University of Nevada, Las Vegas, USA. ⁵Miami University, Oxford, USA. ⁶University of Connecticut, Storrs, USA. ⁷University of Rhode Island, Narragansett, USA. ⁸Rutgers University, New Brunswick, USA. ⁹Arizona State University, Tempe, USA

Abstract

Life in Antarctica and the Southern Ocean is particularly susceptible to climate change as many Antarctic ecosystems lie at critical thresholds (e.g., temperature, nutrients, light) where shifts in ecological balance are threatened. Understanding how Antarctic organisms and assemblages acclimate and adapt to climatic shifts is essential in conservation efforts, including forecasting critical changes in the carbon cycle and food webs. Likewise, understanding cascading impacts such as ocean stratification, loss of sea ice, introductions of nonpolar species, shifts in species community dynamics, among many others is paramount. The blueprints of evolutionary history and the potential of organisms, assemblages, and communities to adapt to environmental change can be deciphered through their genomes, and in the ways that their transcriptomes, proteomes and epigenomes respond to pervasive stressors and infection pressures. With a technology-enabled suite of ‘omics tools, scientists are primed to address key questions that will transform our understanding of life inhabiting diverse continental and oceanic Antarctic ecosystems. The USA life sciences research community conducted a workshop in the northern hemisphere Fall 2022 to build a sustainable, networked scientific community to engender ideas that will serve as the foundation for an initiative that will hone scientific knowledge and support significant advances in understanding diversity, adaptation and survival across Antarctic life. As part of this effort, we investigated the current state of Antarctic genomes and metagenome sequenced. This has helped frame an understanding of the impacts of this rich information on Antarctic population diversity, genome evolution and adaptive features, as well as identify taxonomic and ecosystem gaps. These results are intended to catalyze the next steps in formulating a plan for the USA and the international Antarctic life sciences community to partner through imagining an ‘omics-informed future to foster scientific understanding and decision-making of Antarctic ecosystems and the life that thrives in them.

1357

Preliminary genetic analysis of moss species and its relationship with recently deglaciated areas in Southern Patagonia and Fildes Peninsula, Maritime Antarctica

Dr Ingrid Hebel¹, Karol Kinzel¹, Estefania Jofre¹, Dr Ricardo Jaña², Dr Gino Casassa¹

¹University of Magallanes, Punta Arenas, Chile. ²Chilean Antarctic Institut, Punta Arenas, Chile

Abstract

Climate change increasingly lead more glacier melting and it is a global concern of the impact of warming trend. Numerous studies about the relationship between glaciers retreat and vegetation succession have been carried out on glaciers in Alaska, Scandinavia, Alpine regions, and sub-Antarctic regions (Chapin & Korner 1994; Frenot et al. 1998; Vetaas 1997; Whittaker 1993), but there is little data about the genetic structure of colonized ice-free areas. The ecological role of moraines for storage, collection and transport is not well understood. Also, the founder effect in the newly established populations can be dramatically affected at the glacier fronts by glacier fluctuations (Mizuno 2005; Yang et al. 2008). Moreover, there is a big concern among researchers, not only because of the damage that climate change and anthropic activities can do; but also because of the colonization by no native and invasive species in the new ice-free areas, influencing genetic pollution and introgression following hybridization (Ellstrand & Schierenbeck 2000; Potts et al. 2003; Soltis 2013). Thus, the importance of establishing the genetic origin of the colonization in these new ice-free areas represents a challenge and a duty for conservation efforts. Therefore, this work aims to characterize moss species through a phylogenetic approach in recently deglaciates areas on two glaciers at Southern Patagonia, as well as, on Fildes Peninsula in Maritime Antarctica, to determine the plant colonization tendencies between 2005 and 2017 on the new ice-free areas. Our study showed that colonization came mostly from genotypes developed inside of southern Patagonia and maritime Antarctica. Exotic genome or higher genotypic (dis)similarity was not observable. We support the presence of a haplotype living in the southern part of Tierra del Fuego because of the particular abiotic condition surrounded by glaciers that facilitated the settlement of these species in the neighbors’ ice-free areas.

1358

Recent regime transition of East Antarctic shelf seas

dr Laura Herraiz Borreguero¹, Prof Alberto Naveira Garabato², Dr Oana dragomir²

¹CSIRO, Hobart, Australia. ²National Oceanographic Center-University of Southampton, Southampton, United Kingdom

Abstract

Uncertainties in future global sea-level rise projections to 2100 are driven by the unknown response of the Antarctic Ice Sheet to climate change. The ocean plays a significant role in current Antarctic ice sheet mass loss, and it will continue to do so in the future. The response of the ocean to increased glacial freshwater source is unknown. However, the changes within the Antarctic marginal are starting to show in the observational record in East Antarctica. Here, Vincennes Bay has shown the first evidence that a regime transition from a cold shelf, dominated by cold Dense Shelf Water and representative of large areas of the East Antarctic marginal seas, to a warm shelf, dominated by warm Circumpolar Deep Water and representative of the West Antarctic marginal seas. Here we show further evidence of hydrographic and circulation changes observed in other parts of East Antarctica; And we discuss the role of the difference sources of freshwater in explaining the causes for such a transition.

1361

Divergent behavioral and physiological strategies drive differential performance of two common Trematomids under climate change stressors

Amanda Frazier, Dr Milica Mandic, Andrew Naslund, Dr Kenneth Zillig, Dr Anne Todgham

University of California, Davis, Davis, USA

Abstract

Due to uncurbed anthropogenic CO₂ emissions, polar ecosystems are experiencing ocean warming (OW) and ocean acidification (OA) at the fastest rates on Earth. Antarctic species are thought to be especially unprepared for rapid environmental change, as they evolved in extremely stable and isolated environments for 10-14 million years. Elucidating interspecific physiological and behavioral capacities is critical to inform our predictions on potential Antarctic community and ecosystem shifts in future oceans. This study examined the physiological and behavioral strategies of Trematomus bernacchii and Trematomus pennellii, two of the most abundant benthic fishes in the near-shore shelf ecosystem, under co-occurring OW and OA stressors. Physiological metrics included resting metabolic rate to understand resting energy requirements and Fulton’s condition factor as a proxy for energy stores; together, describing each species’ energetic status. Behavioral metrics included the novel tank test to understand exploratory activity and the novel object test to assess anxiety. To date, T. bernacchii have been studied in greater detail than other benthic Trematomids and have been treated as the representative of the Trematomus genus. However, there is evidence that T. pennellii may have a higher capacity to cope with warming than T. bernacchii. Based on the existing literature, we predicted that T. pennellii have a higher capacity than T. bernacchii to cope with co-occurring OA and OW. This is significant, as T. bernacchii are more abundant in the ecosystem and may be at risk of niche compression under climate change. Thus, in future oceans, T. bernacchii may be the loser, while the underdog fish T. pennellii may be the winner.

1363

Cosmic microwave background measurements from the South Pole

Dr. Amy Bender^1,2, SPT Collaboration³, CMB-S4 Collaboration³

¹Argonne National Laboratory, Lemont, USA. ²KICP, University of Chicago, Chicago, USA. ³-, -, USA

Abstract

The remarkably transparent and stable atmospheric conditions and excellent support of the U.S. Antarctic program have made the South Pole a premier site on Earth for conducting ultrasensitive measurements of the faint anisotropy of the cosmic microwave background (CMB). Early CMB measurements from the South Pole revealed the make-up of the universe and discovered the polarization anisotropy, helping to establish the widely accepted ΛCDM cosmological model. Ever more sensitive experiments with the 10-meter South Pole Telescope and the BICEP/Keck telescopes have led to the discovery of distant clusters of galaxies, early dusty star forming galaxies, and world-leading constraints on primordial gravitational waves. This talk will review latest results from the South Pole Telescope, focusing particularly on those from the currently observing SPT-3G camera and future plans. I will also introduce the planned CMB-S4 experiment, which builds on the technology and success of the polar CMB program, which will conduct a transformative survey from the South Pole.

1367

GEODETIC MASS BALANCE OF 8 GLACIERS IN THE CENTRAL ANDES OF CHILE

Dr Gino Casassa^1,2, Dr Cedomir Marangunic¹, Mr Ashley Apey¹, Mr Felipe Ugalde¹, Ms Martina Toledo¹, Ms Helena Valenzuela¹, Mr Cristian Peralta¹, Dr Inés Dussaillant³, Dr Christian Sommer⁴, Dr Matthias Braun⁴

¹Geoestudios, San José de Maipo, Chile. ²University of Magallanes, Punta Arenas, Chile. ³University of Zurich, Zurich, Switzerland. ⁴Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany

Abstract

Independent calculations of glacier mass balance can be provided by the glaciological and geodetic methods. The glaciological method relies on point measurements of the surface mass balance, at seasonal or annual timescale, while the geodetic method computes surface elevation differences at high spatial resolution, to assess the total mass balance, including surface, internal, and basal mass balances, typically over a period of several years or decades. In this contribution, we present results of geodetic mass balances for 8 glaciers (2 rock glaciers, 2 debris-covered glaciers, and 4 debris-free glaciers) at Yerba Loca basin, located 30 km NE of Santiago, in the central Chilean Andes, based on a unique set of annual airborne LiDAR surveys for the period 2012-2022 (except 2013), in addition to a 1996 photogrammetric survey. Elevation differences (dh/dt) based on 1 m spatial resolution DEMs were computed for the 8 glaciers, and converted to mass balance values based on estimated ice densities of 0,85 g/cm3 (Huss, 2013), with thickness change uncertainties less than 10 cm/y. Mass balance values range from a minimum of –2.8 m/y for the debris-free glacier Paloma Este to a maximum of +7 cm/y for the “58” rock glacier (Marangunic et al., 2021). 95% of the annual mass balances are negative, attributed to long-term climate warming in the region, and reduced precipitation due to the megadrought that has affected a major part of Chile since 2010. To assess the performance of the satellite products, the high-resolution LiDAR results are compared with dh/dt data published from ASTER optical satellite data of Dussaillant et al. 2019 and Hugonnet et al. 2021; and TerraSAR TanDEM-X radar satellite data of Braun et al. 2019 for the same area in Yerba Loca basin.

1369

International Principles and Procedures for Antarctic Place Names

Cole Kelleher

Polar Geospatial Center, Saint Paul, USA

Abstract

Antarctic place names have long been a part of the legacy of national Antarctic programs and today, more than ever, are important for identification, orientation, positioning and

navigation, providing an essential reference system for logistical operations

(including search and rescue measures), management, environmental investigation

and protection, scientific research, culture, tourism, and preservation of heritage.

They facilitate the exchange of information in the field, in scientific publications and in

administrative measures of the Antarctic Treaty System. Place names also reflect

the history of exploration of the continent.

Antarctica has no single overarching naming authority. Historically each signatory nation's naming authority established its own principles and policies in regards to Antarctic place names. In many cases, this approach has resulted in Antarctic features having multiple names, the mistranslation of Antarctic place names, and ambiguity and confusion around the current use of Antarctic place names. To help align Antarctic place naming across international Antarctic programs, SCAR's Standing Committee on Antarctic Geographic Information (SCAGI) developed the International Principles and Procedures on Antarctic Place Names which have been published by SCAR. These principles and procedures provide signatory nations with a framework for standardized, consistent, and accurate place naming practices in the Antarctic. In 2023, the United Nations Group of Experts on Geographic Names (UNGEGN) endorsed these principles and procedures. In this presentation, a detailed overview of the International Principles and Procedures for Antarctic Place Names will be provided along with additional resources signatory nations and their respective naming authorities may reference when naming new features in the Antarctic.

1370

The representation of South Americans in Anglophone Antarctic fiction

Dr Pablo Wainschenker¹, Professor Elizabeth Leane²

¹Gateway Antarctica, University of Canterbury, Canterbury, New Zealand. ²School of Humanities, University of Tasmania, Hobart, Australia

Abstract

Recent scholarship has examined the representation of Antarctica in both Anglophone and Hispanophone fiction, noting the similarities and differences between the two and showing the complexity of the relationship between these perspectives. Underneath the surface, Anglophone and Hispanophone Antarctic narratives rely on assumptions not always shared across languages.

In this exploratory work, we build on this scholarship by examining what happens when Anglophone novelists writing about Antarctica depict South American characters. Focussing on novels published in the period since the signing of the Antarctic Treaty that include prominent South American characters, we ask a series of questions: How do representations of South Americans in English language fiction change over the last decades, if at all? To what extent do these depictions repeat or challenge pre-existing national stereotypes? And how are these representations informed (or not) by the broader geopolitics of Antarctica?

With this presentation, we aim to enrich our understanding of the intersecting imaginary worlds of Antarctic narratives, prompting reflection on the influence of cultural assumptions within these literary realms.

1375

Application of satellite imagery to identify silica-rich rock for future cosmogenic nuclide exposure dating in remote unvisited areas of Antarctica

Mr Jonathan Adams^1,2, Dr Philippa J Mason¹, Dr Stephen J Roberts², Dr Dylan H Rood¹, Prof John L Smellie³, Dr Joanne S Johnson²

¹Imperial College London, London, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Leicester, Leicester, United Kingdom

Abstract

Rock outcrops protruding above the ice surface in Antarctica (nunataks) can provide direct geologic evidence for past ice sheet fluctuations through the measurement of concentrations of cosmogenic nuclides that accumulate in their surfaces once the rock is exposed. Felsic lithologies, typically pale in colour and dominated by quartz, feldspars, and micas, are suitable for exposure age dating since quartz is the often-preferred target mineral for extraction of cosmogenic isotopes which make deglacial reconstructions possible. The geology of rock outcrops in Antarctica are, however, often sparsely mapped and many exposures are challenging to access. Satellite-based spectral mapping offers an effective way to characterise the geology of large areas of exposed rock rapidly and safely in regions where it is logistically challenging to conduct fieldwork, enabling a preliminary characterisation of an area’s suitability for eventual targeted retrieval of cosmogenic nuclide samples.

Here we assess the potential of multispectral remote sensing using both the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and very high-resolution Worldview-3 (WV-3) imagery to distinguish felsic from mafic rock outcrops at visible-near infrared (VNIR) and shortwave infrared (SWIR) wavelengths. At Mount Murphy, a remote site in West Antarctica, we identify four dominant rock types from our spectral mapping: granites, gneisses, basalt and fragmental hydrovolcanic rocks. Image derived spectral profiles of these four rock types were used as input for spectral classification and lithological mapping of the Mount Murphy site. Supervised classification results indicate that WV-3 performs well at differentiating felsic from mafic rock types and that ASTER imagery, while coarser in resolution, can also achieve satisfactory results, and could therefore be used in concert with more targeted WV-3 image acquisitions. Overall, our results demonstrate the potential of spectral mapping and classification using WV-3 and ASTER datasets to identify and characterise suitable sites for future cosmogenic nuclide sampling campaigns.

1376

South American Antarctic Utopias

Dr Pablo Wainschenker

Gateway Antarctica, University of Canterbury, Christchurch, New Zealand

Abstract

Recent scholarship has retrieved a little-known Antarctic utopia published in the Spanish language in the late nineteenth century. This exploratory paper builds on this finding and expands it by examining other utopian and dystopian South American Antarctic narratives. Comparing these works with non-Antarctic utopias in contemporary Hispanophone narrative, the paper asks: what is the role of South American Antarctic utopias in Latin American fiction? What do these texts tell us about the relationship between South America and the southernmost continent? Is there any relationship between these imaginary visions and classic polar utopias in Anglophone narratives?

1382

The mass balance record of the Martial Este Glacier (Tierra del Fuego, Argentina) shows behavior connections with glaciers in the Antarctic Peninsula Region.

Prof. Rodolfo Iturraspe, Mg. Adriana Urciuolo

Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina

Abstract

We report on the findings of a 24-year monitoring program of the Martial Este glacier, one of the three main bodies of the Martial glacier, situated in Tierra del Fuego, Argentina, at the northern shore of the Beagle Channel, near Ushuaia city. The Martial Este is representative of the small local glaciers that have retreated to the headwaters of their respective cirques. In the context of a general recessive behavior, changes on the Martial Este mass balance tendency have been identified. The prevailing negative trend of -450 mm/a^-1, which had persisted at least since 1984, gave way to a steady and somewhat positive state (-69 mm a^-1) during the 2006-2016 period. Following that, there was a resumption of the negative glacier behavior with a -643 mm a^-1 trend. This stable period involved a succession of positive and negative balances and the occurrence of surpluses of +930mm and +543mm in 2009-2010 and in 2013-2014 respectively. Between 2006 and 2016, there was a rise in the annual precipitation and a decrease in temperature throughout the temperate semester (October to March), with persistent snowfall on the glacial environment, mostly during the summer months (December-February). A significant relationship is observed when these results are compared to mass balances published by the World Glacier Monitoring Service for the Johnsons, Hurd, and Bahía del Diablo glaciers, located in the area of the Antarctic Peninsula. This agreement is especially evident in the highly positive and negative years, indicating that the occurrence of well-defined temperature and humidity events respond, north and south of the Drake Passage to similar climatic drivers. On the other hand, this glaciers response and the Southern Annular Modem Index comparison does not show a suitable agreement for the specified decadal timeframe.

1385

Contrasting the effect of geographical distance, ocean currents and environmental variation in population connectivity of Harpagifer antarcticus along Maritime Antarctica

Dra. Valentina Bernal-Durán¹, David Donoso^1,2, Dra. Andrea Piñones^1,3,4, Per Jonsson⁵, Dra. Laura Benestan⁶, Dr. Mauricio Landaeta^7,8, Javier Naretto⁹, Dr. Claudio Gonzalez-Wevar^1,3, Dra. Pilar Haye^10,11,12, Dr. Elie Poulin¹, Dr. Nicolas Segovia^10,11

¹Instituto Milenio Biodiversidad de Ecosistemas Antárticos y subAntárticos (MIBASE), Santiago, Chile. ²Pontificia Universidad Católica de Valparaíso, Valparaiso, Chile. ³Instituto de Ciencias Marinas y Limnológicas (ICML) y Centro FONDAP IDEAL, Universidad Austral de Chile, Valdivia, Chile. ⁴Centro COPAS COASTAL, Universidad de Concepción, Concepción, Chile. ⁵Department of Marine Sciences, Tjärnö Marine Laboratory, University of Gothenburg, Strömstad, Sweden. ⁶Institut Français de Recherche pour l’Exploitation de la Mer, Centre du Pacifique, Vairao, Tahiti, French-Polynesia. ⁷Laboratorio de Ictiología e Interacciones Biofísicas (LABITI), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile. ⁸Centro de Observación Marino para Estudios de Riesgos del Ambiente Costero (COSTA-R), Universidad de Valparaíso, Viña del Mar, Chile. ⁹Costa Humboldt, Puerto Varas, Chile. ¹⁰Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile. ¹¹Instituto Milenio en Socio-ecología Costera (SECOS), Coquimbo, Chile. ¹²Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile

Abstract

Geographical distance, ocean currents and environmental variability could represent barriers for individual exchange between local populations. Determining the influence of these factors on population connectivity is essential for the biodiversity conservation and population persistence, also considering the global change effects in marine ecosystems. Besides, spatiotemporal heterogeneity in environmental variables can produce patterns of local adaptation, which could counteract the homogenizing effect of gene flow. Within Maritime Antarctica, the Western Antarctic Peninsula (WAP) and South Georgia Island (SGE) regions are separated by more than 1000 km, showing complex oceanographic dynamics and marked seasonality in environmental conditions (temperature, ice cover and primary productivity gradients). In this study, the fish Harpagifer antarcticus was used as model species to compare neutral and putatively adaptive genetic structure, and the effect of geographic distance, ocean currents and 32 environmental variables on population differentiation. For this, ~27.000 SNPs obtained from GBS, Lagrangian particle tracking model and seascape genomics methods were used. The neutral genetic structure showed a clear differentiation between WAP and SGE. An important effect of geographic distance on population structure was estimated, confirming a pattern of isolation by distance. The Lagrangian particle simulations showed areas of local retention inside the WAP and limitation for larval exchange between this region and SGE, generating dispersal barriers. Also, a significant effect of primary productivity and ice cover was estimated, which would be limiting population connectivity between WAP and SGE due to seasonal variations. Not enough evidence to suggest patterns of local adaptation, between the populations of H. antarcticus from WAP and SGE, was detected. Therefore, the observed genetic differentiation patterns would be reflecting limitations to gene flow, due to the effect of geographic distance, oceanographic currents and environmental variation which represent barriers to population connectivity for H. antarcticus.

1387

“A picture is worth more than a thousand words”: the visual aspects of communicating Antarctic science to the public.

Dr Gabriela Roldan¹, Mr Pablo Ruiz Teneb²

¹Gateway Antarctica, University of Canterbury, Christchurch, New Zealand. ²Instituto Antartico Chileno, Punta Arenas, Chile

Abstract

At the 2023 Antarctic Treaty Consultative Meeting, Treaty Parties adopted the Helsinki Declaration on Climate Change and the Antarctic. Among other points, Parties have committed to intensify efforts to communicate locally and globally the devastating effects of the climate crisis and the urgent need for prevention and mitigation plans. Treaty Parties are encouraged to rely on the science community for accurate information to advocate in this cause.

However, effectively communicating complex global science issues to different audiences requires a multidisciplinary approach. Science communication is often approached in oral and written forms, often including data visualizations and complicated graphs attempting to connect with the general public, non-specialist and specialist audiences alike in one message.

This paper discusses the role of graphic design in science communication to broader audiences. Visual language has proven to be a highly effective form of science communication, spanning across ages, gender, cultures and learning levels. However, the visual aspects of science communication are poorly understood; visual materials are typically treated as ad-on illustrations rather than being the core message. We present a summary of the work of a graphic designer and Antarctic science communicator who has worked in the field for more than a decade, and we advocate for the integration of visual and information design in communication, education and outreach efforts for the better understanding of Antarctica.

1390

A conversation starter on bird flu and the privilege of being human in Antarctica

Dr Gabriela Roldan

Gateway Antarctica, University of Canterbury, Christchurch, New Zealand

Abstract

The highly pathogenic strain of avian influenza H5N1, also known commonly as bird flu, was confirmed affecting Antarctic wildlife during the 2023-24 summer season. Worldwide, the contagious viral disease decimated wild bird populations, also affecting mammals. In November 2023, scientists from the British Antarctic Survey confirmed the virus had reached the bird and mammal populations of the sub-Antarctic South Georgia Island. It was a matter of when and not if, the deadly virus would spread into Antarctica’s shores.

The Antarctic science community had anticipated the spread of the deadly virus since the global panzootic was declared in 2021. Science monitoring projects, risk assessments protocols and guidelines were created and shared with all Antarctic actors, including National Antarctic Programmes and the tourism industry. Reporting on sightings of suspected and confirmed cases in the region were encouraged and collated by official agencies.

However, human activities in the Antarctic did not diminish, despite the potential impact this viral disease may have on the continent's wilderness value, one of the core values enshrined in the Antarctic Treaty System. Record number of tourists are expected to visit Antarctica in the current season, while science programmes continue with business as usual.

This paper argues over the moral, ethical and political aspects of human-animal relationships in Antarctica. It questions the conflicting scenario over the shared use of the Antarctic environment for the gains of scientific endeavours and recreational purposes.

1391

Resilient Responses: Dealing with power outages on O’Higgins Base

Resilient Responses: Dealing with power outages on O’Higgins Base Natalia Fierro

Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

As weather conditions in Antarctica become more extreme as a result of climate change and related factors it is important to learn from experience how better to deal with exceptional circumstances as they occur. This presentation covers a case study in February 2024 of responses to power outages at O’Higgins base from a first-hand account. The O’Higgins Base is one of the largest Chilean bases on Antarctica and is primarily a military base where some researchers are housed during their periods of field work. The military personnel are in charge of all operations there. During my visit as a scientific coordinator, there were several power outages in February 2024. The Captain commanding the base did not inform the research teams of what was happening regarding or why systems were failing. During energy outages the base was left without electricity, heating, cooking and hot water at a time when research teams were preparing their equipment to collect samples. This paper provides an account of how teams coped with the lack of energy. It covers issues of communications between personnel, behavioural responses to the emergency and includes discussions about how better the situation could have been covered from the point of view of building occupants and also from the side of those managing the problems that continued over the course of a whole weekend, in the cold. There were following intermittent power cuts and moments without energy and resolution involved the exchange of dialogues between the military and the researchers. A number of valuable lessons could be learnt from these experiences about longer term resilience of inhabitants of Antarctic bases including communications protocols to ensure that people are not left with no options to act, work and survive in the extreme climate of the region when such problems arise.

1392

Penguins in the wind: colony geomorphology as a link between weather and breeding success.

Albert Palomino-González^1,2,3, Dr. Andrea Piñones^1,2,4,3, Dr. Lucas Krüger^5,3, Dr. Virginia Morandini⁶, Dr. Josabel Belliure⁷, Dr Juli Broggi⁶, Suman Ghosh⁸, Elisa González⁹, Dr. Ángela Vázquez-Calvo¹⁰, Dr. Antonio Alcamí¹⁰, Dr. Andrew D. Lowther¹¹

¹Instituto De Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ²Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes, Valdivia, Chile. ³Millennium Biodiversity Institute of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile. ⁴Centro de Investigación Oceanográfica COPAS-COASTAL, Concepción, Chile. ⁵Instituto Antártico Chileno, Punta Arenas, Chile. ⁶Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain. ⁷Universidad de Alcalá, Alcalá de Henares, Spain. ⁸Technical University of Berlin, Berlin, Germany. ⁹Laboratorio de Biodiversidad Molecular, Pontificia Universidad Católica de Chile, Santiago, Chile. ¹⁰Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain. ¹¹Norwegian Polar Institute, Tromsø, Norway

Abstract

As mesopredators, penguins have long been considered indicators of change in the ecosystem. Chinstrap penguin colonies show a generalized decline in the Antarctic Peninsula, a region where climate is experiencing some of the highest rates of change. However, responses to climate change are complex and demographic variability can also occur at a local scale, concurrent to the trends observed regionally. In the case of the congeneric Adélie penguin, neighboring colonies have been reported to follow different or even opposed trends. The influence of geomorphology on nesting habitat quality has been suggested as a mechanism driving differing trends at a local scale, a hypothesis termed as landscape effect. Variables such as snow accumulation, exposure to wind and proneness to flooding are determined by the local geomorphology and are known to influence breeding success in penguins.

In this study, we aimed to test the landscape effect hypothesis in chinstrap penguin colonies of the northern Antarctic Peninsula. To do so, we monitored two breeding colonies in the South Shetland Islands: Harmony Point, on Nelson Island in 2022/23, and Vapour Col, on Deception Island in 2024. We estimated breeding success by performing nest and chick counts over drone-derived orthomosaics. Subcolony-specific terrain attributes, including aspect, steepness, flow accumulation and wind exposure were retrieved from 3D digital elevation models. Differences in breeding success between subcolonies were detected in both years. We then explored differences in terrain attributes, along with subcolony characteristics, and assessed the correlations with breeding success. Improving our understanding of local population dynamics in chinstrap penguins, including the effects of terrestrial factors, is essential for developing better population models of this indicator species.

1394

Multi-index analysis of ionospheric disturbances observed during space weather events over Antarctica

Dr. Giorgio Picanço¹, Anabella Urutti², Dr. Luciano Mendoza², Dr. Amalia Meza², Dr. Maria Paula Natali²

¹University of Vale of Paraíba (UNIVAP), São José dos Campos, Brazil. ²National University of La Plata (UNLP), La Plata, Argentina

Abstract

In this work, we present a study of the ionospheric disturbances observed over the Antarctic continent during two significant space weather events. To accomplish this, we analyzed data from two ionospheric indices: the Disturbance Ionosphere indeX (DIX) and the Rate of Change of Total Electron Content Index (ROTI). Specifically, we chose two marked events from Solar Cycle 24: an intense geomagnetic storm that occurred on March 17–18, 2015 (St. Patrick's Day geomagnetic storm) and a preceding geomagnetic substorm from March 10–13, 2015. Our results reinforce that the ionosphere can undergo disturbances at different levels resulting from a combination of internal and external physical processes. In this context, the DIX revealed the impact of disturbed electric fields during the intense geomagnetic storm, while ROTI data displayed significant irregularities during the storm's recovery phase. Meanwhile, the DIX showed changes in the plasma concentration during the substorm occurrence, whereas the ROTI indicated a different behavior concerning the polar region irregularities. We based these conclusions on the observed behavior of the indices before, during, and after the analyzed space weather events. Finally, we used supplementary data, such as interplanetary and geomagnetic indices, to support our analysis.

1395

Island Hopping Penguins: An Evolutionary Tale of Divergence and Adaptation Across Ocean Fronts

Dr Fabiola León^1,2,3, Msc Eduardo Pizarro^1,2,3, Dr Nicolas Lois⁴, Dr Maria Jose Frugone⁵, Dr Francesco Bonadonna⁶, Dr Phil Trathan⁷, DR Andrea Polanowski⁸, Dr Andrea Raya-Rey⁹, Dr Antje Steinfurth¹⁰, Dr Rauri Bowie¹¹, Dr Elie pulin^1,12, Dr Juliana Vianna^2,1,3,13,14

¹Instituto Milenio Biosiversidad de Ecosistemas Antárticos y Subantárticos, Santiago, Chile. ²Universidad Catolica de Chile, Santiago, Chile. ³Instituto Milenio CRG, Santiago, Chile. ⁴Instituto de Ecología Genética y Evolución de Buenos Aires, Buenos Aires, Argentina. ⁵Instituto Milenio CRG, Santiago, Chile. ⁶Univ Montpellier, Montpellier, France. ⁷British Antarctic Survey, Cambridge, United Kingdom. ⁸Australian Antarctic Division, Tasmania, Australia. ⁹Centro Austral de Investigaciones Científicas, Ushuaia, Argentina. ¹⁰University of Cape Town, Rondebosch, South Africa. ¹¹University of California, Berkeley, USA. ¹²Universidad de Chile, Santiago, Chile. ¹³Nucleo Milenio Lili, Santiago, Chile. ¹⁴Instituto para el Desarrollo Sustentable, Santiago, Chile

Abstract

Stepping stone oceanic islands are suitable landscapes models for comprehending population divergence, speciation, and rapid adaptation. Despite the absence of obvious barriers among islands, the cryptic constraints but also connectivities imposed by the ocean play a crucial role in shaping the dispersal of gene flow and thereby influencing spatial genetic variation. This diversity arises from a complex interplay of evolutionary mechanisms, including multiple founder effects, responses to diverse selective pressures, the exploitation of various ecological niches, and the acquisition of local adaptations. Rockhopper penguins Eudyptes chrysocome, E. filholi and E. moseleyi are distributed in islands with different sizes and degrees of isolation from the mainland or by an oceanic barrier such as the subtropical front (SF). In this study, we analyze the genomic diversity by evaluating population structure, gene flow patterns, signature of selection, and intra- and interspecific demography history of the three rockhopper species. For this, we resequenced genomes from 59 individuals from the three rockhopper species along with their distribution. We found that species are well delimited from each other with varying levels of intraspecific differentiation. We identified historical and ancestral demographic fluctuations discordant among species, all with gradual and progressive decreases in contemporary times. We detected introgression between Rochopper and Macaronis penguins. The results of Genotype Association Analysis suggest the existence of adaptively correlated SNPs with the temperature patterns and precipitation with the species. ⁤Positive selection analyses based on extended haplotype revealed signals of selection related to diving habits and response to hypoxia and thermoregulation. ⁤⁤Gene families expanding related to DNA methylation and wound repair were identified. ⁤⁤Our study unveils complex micro and macroevolutionary dynamics , including species delimitation,population structure, introgression, and adaptive genomic variation driven by environmental in subantarctic oceanic island elucidates not only past history but also on the current trajectory of Rockhopper linages.

1402

MECEM – a new Model for Elevation Change Estimation in Antarctica from ICESat-2 altimetric Data

Prof. Rongxing Li¹, Mr. Youquan He¹, Mr. Hongwei Li¹, Mr. Yuanyuan Gu¹, Ms. Guojun Li¹, Prof. Gang Qiao¹, Prof. Huan Xie¹, Prof. Tong Hao¹, Dr. Xiangbin Cui²

¹Center for Spatial Information Science and Sustainable Development and Applications, College of Surveying and Geo-informatics, Tongji University, Shanghai, China. ²Polar Research Institute of China, Shanghai, China

Abstract

We present results of our efforts in development of a new model for ICESat-2 data processing and its application in mass balance estimation in Antarctica. ICESat-2 carries a photon-counting laser altimeter with an unprecedented elevation accuracy of 2-4 cm. It is important to establish a new data processing model that can take advantage of this satellite for accurately estimating volumetric changes in Antarctica and associated contribution to global sea level rise. We introduce an innovative Multi-temporal Elevation Change Estimation Model (MECEM) that separates precipitation effects from topographic influences to eliminate their correlations and estimates the elevation change rates effectively through a spatio-temporal iterative procedure. The MECEM results are validated by using GNSS in-situ observations, snow stakes measurements, and airborne altimetric survey data. The results are also compared with those from Cryosat-2, ICESat, and other mission data. It is demonstrated that the model is capable of estimating small thickening of 1.8±0.1 cm yr^-1 in the Vostok subglacial lake region. Using ICESat-2 ATL06 data from 2019 to 2023, the model is proven to be effective in the estimation of elevation change rates in Antarctic basins of different characteristics. Our results show that an increase of 0.103±0.001 m yr^-1in thickening is found from 2017-2021 to 2019-2023 in Dronning Maud Land. Furthermore, an accelerated thinning by -0.12±0.035 m yr^-1 is witnessed from 2003-2019 to 2019-2023 in the fast-flowing Pine Island Glacial. With more ICESat-2 data acquired, the developed MECEM model can be applied for estimating the contribution of the entire Antarctic ice sheet to global sea level rise.

1406

Water/Log (extracts)

Dr Adrienne van Eeden-Wharton

University of Pretoria, Pretoria, South Africa

Abstract

This presentation of extracts from Water/Log, will centre on new creative work-in-progress produced during the annual takeover voyage to the research base at Marion Island in the southern Indian Ocean as part of the South African National Antarctic Programme. Water/Log is an ongoing body of site-responsive creative praxis focusing on the intertwined environmental histories linking the southern African coast and adjacent islands, the sub-Antarctic islands, and the South Atlantic, southern Indian and Southern oceans. It includes durational sound recordings, video and photography from sites associated with the historical exploitation of marine animals, many of which are now protected areas. This work goes beyond straightforward documentation and emphasises the embodied and affective experiences of being ‘at sea’ and ‘in the field’. Through a combination of prose, still images, and sound and video installation, I try to find ways of translating and ‘bringing home’ such experiences – creating the space for audiences to imaginatively engage with these environments, their fraught histories and increasingly vulnerable futures.

My (often-solitary) practice has been shaped by years of walking the shores of the southern African coast and adjacent islands. In this presentation, however, I will discuss what I have learned as a member of the research team for the African Antarctic Artist and Writers Programme pilot project – a unique opportunity for interdisciplinary conversation and collaboration.

1407

Learning from blood- and oil-soaked histories

Dr Adrienne van Eeden-Wharton

University of Pretoria, Pretoria, South Africa

Abstract

In this presentation, I will discuss the invaluable role that archival materials have played in helping me trace transoceanic modern whaling histories spanning the South Atlantic, Indian and Southern oceans – from the waters along the coasts of southern Africa to the sub-Antarctic and Antarctic whaling grounds. Primary sources include official telegrams and letters; accounting records, meeting minutes and annual reports; applications for permits and concessions; deeds of sale, lease agreements and insurance claims; newspaper clippings and industry-specific gazettes; ship logbooks, diaries and crew lists; charts and blueprints; personnel and accident registers; biological specimens and product packaging; photographs, films and ‘memorabilia’. Together with my own creative work in former sites of slaughter – environments which, too, are archives bearing marks of histories of exploitation and violence, sometimes all but invisible.

Highlighting not only rapid pelagic expansion and developments aimed at more efficient ‘catching’, ‘processing’ and ‘utilisation’ of cetacean bodies, but also the entanglement of the whaling industry in territorial claims, twentieth-century warfare and post-war international negotiations, archival materials give us a sense of the sprawling networks of capital, control and coerced labour that enabled slaughter at this vast scale. Following the development of early cetacean science alongside conservation regulations based on concepts like ‘rational exploitation’ and ‘stock management’ – aimed at protecting a highly profitable industry and the interests of nations and corporations – may help us come to terms with some of the complexities of contemporary ocean conservation and marine conservation biology.

1409

Understanding the variation within species in habitat utilization is important in assessing species' resilience to environmental disturbances.

Prof Daniel Costa¹, Prof Louis Huckstadt², Dr Rachel Holser¹

¹University of California, Santa Cruz, USA. ²University of Exeter, Penryn, United Kingdom

Abstract

Our understanding of species habitat utilization patterns is often limited to specific regions with limited data on species movement patterns. This is particularly problematic when animal tracks are obtained from a single colony or a section of the species range, hindering our ability to fully understand the within-species variability in patterns of species habitat utilization from such limited information. Here, we examine the pitfalls of this approach using a suite of large tracking data sets collected over the entire species range for four pinniped species: northern and southern elephant seals, crabeater seals, and Weddell seals. We found that species with very restricted diets, like crabeater seals, present the least variability in their habitat utilization patterns. In contrast, with generalist diets, species like elephant seals and Weddell seals exhibit large individual and site-specific plasticity over a larger range of habitats. Our study highlights how variable the movement patterns of animals are within a species. It highlights the importance of broad comparative studies of patterns of habitat utilization from across their species' entire geographic range.

1414

SLIDE – Southern Latitudes Island Dispersal Evaluation

Professor David Pearce¹, Dr Lucie Malard², Professor Julia Schmale³, Dr Janina Rahlff⁴, Mr Luke Cockerton¹, Professor Peter Convey⁵

¹Northumbria University, Newcastle upon Tyne, United Kingdom. ²University of Lausanne, Lausanne, Switzerland. ³EPFL, Sion, Switzerland. ⁴Friedrich Schiller University, Jena, Germany. ⁵British Antarctic Survey, Cambridge, United Kingdom

Abstract

The risks of invasions of remote ecosystems by new microorganisms is a major threat as they are likely to impact the diversity and function of resident communities and local ecosystems. In the Antarctic, aerial transport is the primary source of new biological inputs. Airborne communities are believed to be influenced by environmental and climatic conditions, which are already changing rapidly on a global scale, but especially in the Polar regions. Yet, the influence of climate change, weather patterns and environmental conditions on these airborne communities are still unclear. One of the key challenges in understanding these processes is the high heterogeneity and variability of airborne samples. Following the Antarctic Expedition (ACE), in which daily samples were taken around the Antarctic continent to provide spatial distribution of airborne microorganisms, a time series was conducted at one of the field sites (South Georgia), over a period of two weeks at both high and low altitude to establish daily variability between aerobiological sample sets. Results showed that although there was a high heterogeneity and variability within the sample sets, reliable patterns in the overall diversity could still be established, and hence single daily samples can still provide useful assessment of aerial diversity over spatial and temporal scales in the Antarctic.

1421

Life on the edge: resistance mechanisms to desiccation and re-wetting of two Antarctic Nostoc sp. strains from freshwater and terrestrial habitats

Dr. Valentina Savaglia^1,2,3, Dr. Beatriz Roncero-Ramos^3,1, Dr. Igor S. Pessi⁴, Dr. Annick Wilmotte¹, Prof. Elie Verleyen²

¹University of Liège, Liège, Belgium. ²University of Ghent, Ghent, Belgium. ³University of Sevilla, Sevilla, Spain. ⁴Finnish Environment Institute, Helsinki, Finland

Abstract

Filamentous heterocystous cyanobacteria belonging to the genus Nostoc are ecosystem engineers in dry and oligotrophic environments worldwide. In Antarctica, the genus is often a dominant member in both terrestrial and lacustrine habitats, yet little is known about its specific adaptations to thrive in both extremely dry and wet conditions, and during its dispersal between habitats. Here we studied the response to short-term desiccation exposure and rehydration of two Antarctic terrestrial (ULC180) and freshwater (ULC008) Nostoc strains sharing 97.7% of ANI similarity. We compared the concentration of different pigments and osmolytes (i.e. trehalose and sucrose), the photosynthetic efficiency as well as the differential gene expression after RNA-seq (Illumina NovaSeq 2x150 bp) between the controls (T0) and the different treatments (D = after 3h of desiccation; RW1 = after 10 min of rehydration; RW2 = 24h of rehydration; RW3 = 72h of rehydration). Both strains reacted to dehydration by accumulating sucrose, whereas trehalose was present in lower concentrations. Only the freshwater strain showed a recovery in chlorophyll a content after 72h of rehydration. Transcriptomic profiles showed that both strains protected their cells during dehydration by inducing stress-related genes, such as those for the production of carotenoids, trehalose and nitrogen fixation, but these were significantly up-regulated only in the terrestrial strain. The latter one responded with a higher number of up-regulated genes compared to the freshwater strain, including those necessary to protect the photosystem II from degradation (e.g. psbA2 gene), enabling a stronger resistance to dehydration of ULC180 compared to ULC008.

1431

A lightweight, high-power, ultra-wideband radar system for polar ice surveys

Drew Taylor¹, Prasad Gogineni¹, Brett Fraysher¹, Allain Rapadas¹, Shriniwas Kolpuke¹, Mishal Thapa¹, Omid Reyhanigalangashi¹, Abhishek Awasthi², Sameer Mulani¹, Changhyun Chung³, Joohan Lee³

¹University of Alabama, Tuscaloosa, USA. ²Paras Anti-drone Technologies, Navi Mumbai, India. ³Korea Polar Research Institute, Incheon, Korea, Republic of

Abstract

Radar ice sounding is critical in understanding ice sheet and bedrock structure, allowing further understanding of ice sheet behavior and composition. Collaborating with the Korea Polar Research Institute (KOPRI), the Remote Sensing Center at the University of Alabama has developed a lightweight, high-power, ultra-wideband radar designed for airborne surveys over the Antarctic ice sheet. This system will contribute to critical advancements in climate and climate change research.

The radar can operate over the 170-470 MHz frequency range at a peak transmit power of 1 kW. The system operates with a 32-element antenna array, with sixteen elements mounted under each platform wing. One subarray of 16 elements operates in switched mode as a transmit/receive array, and the other operates in receive-only mode. Each pair of two elements in the array is combined with a power divider/combiner, allowing the system to operate with eight individual channels, each with one transmit port and two receive ports. Modular channel design allows for in-flight swapping of channels, optimizing flexibility and downtime.

The radar system was installed in a Basler aircraft and flown over several lines near Dome Concordia station in December 2023. Despite weather and logistical challenges, which limited survey time to four days, over 3000 km of data were collected. The quick-look profile spans from surface to bed across the survey, showing the surface response, detailed bedrock, and well-defined internal layering. Further higher-level processing is underway and will be presented at the conference.

This presentation will discuss the project and radar system and the testing in the laboratory and during flight-worthiness certification in Canada. Results from these datasets and the data collection in Antarctica will be presented and discussed.

1433

Discovering Antarctica: Engaging audiences of all ages through an interdisciplinary approach in Ushuaia

Dr. Cristian Lorenzo^1,2, Dr. Daniel Martinioni^1,2, Dr. María Eugenia Raffi^1,2, Lic. Facundo Sota¹, Lic. Stefany Dayana Horta Franco³

¹Centro Austral de Investigaciones Científicas (CADIC) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ushuaia, Argentina. ²Instituto de Ciencias Polares, Ambiente y Recursos Naturales (ICPA) – Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur (UNTDF), Ushuaia, Argentina. ³Maestría en Estudios Antárticos – Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur (UNTDF), Ushuaia, Argentina

Abstract

Delegations in Antarctic forums are facing dilemmas concerning the area south of 60° South latitude, as it occurs with climate change that means alterations in the dynamics of ecosystems and has effects on the present and future of the Antarctic geopolitics. Scientists, working in Antarctic, are trying to answer questions in diverse disciplines and communicate findings through papers, books, and, in some cases, by informing diplomats. Although the role of diplomats and scientists are widely recognized as contributors, it is an opportunity to highlight the work done from bottom-up approaches into societies that add to the legitimacy of the Antarctic order. The objective of this presentation is to share the experiences of two initiatives that have been held in an Antarctic Gateway City (Ushuaia), aimed at adults and kids: The Antarctic Coffee and the Antarctic Science Club. The presentation will cover three analytical points: (1) Actions targeted to different audiences and ages, through different formats; (2) The theoretical framework associated with the learning process for different audiences; and (3) Historical contexts that offer insights into the opportunities, and challenges for implementing these initiatives. Our presentation encourages thinking about Antarctic science in non-formal education.

1435

The Antarctic Polar Front shapes prokaryotic and microeukaryotic communities across the Drake Passage, Southern Ocean.

MSc. Nayla Serey^1,2, Dr. Phyllis Lam³, Dr. Elie Poulin^1,2, Dr. Julieta Orlando^1,2, Dr. Léa Cabrol^2,4

¹University of Chile, Santiago, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ³University of Southampton - National Oceanography Centre Southampton,, Southampton, United Kingdom. ⁴Aix Marseille University, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France

Abstract

The Southern Ocean (SO) is structured by several oceanographic fronts, such as the Antarctic Polar Front (APF) and the Southern Boundary of the Antarctic Circumpolar Current (sBdyACC), that induce pronounced changes in seawater physicochemical characteristics and have been considered barriers to the dispersal of some organisms. However, high-resolution studies are needed to understand their effects on microbial diversity, especially across the Drake Passage, characterized by the shortest Antarctic/Subantarctic distance creating sharp environmental gradients. Here, we evaluated the effect of two major oceanic fronts of the SO on the distribution of prokaryotic and microeukaryotic communities across the Drake Passage between Subantarctic Patagonia and the Weddell Sea. Surface seawater samples (4L) were collected in December 2023 from 22 stations in triplicate (n=66) through the underway peristaltic pump and filtered on 0.22µm aboard ‘Le Commandant Charcot’ (Ponant Cie). Temperature, conductivity, salinity, pH, O₂, and CO₂ concentrations were continuously measured by a FerryBox system. The microbial communities were analyzed by sequencing 16S and 18S rRNA genes (Illumina-Miseq). Three homogeneous zones could be delineated based on their different physicochemical characteristics. Both prokaryotic and microeukaryotic communities showed a clear and consistent separation between the three zones, with different predicted functional profiles. Environmental parameters explained a larger fraction of microbial variability than geographic distances. Interestingly, the strongest community difference occurred between adjacent zones separated by the APF, rather than between the (geographically and environmentally) furthest zones. The main bacterial discriminant taxa were SAR11 and Planktomarina North of the APF, Ulvibacter and Cryomorphaceae in the transition between both fronts, and Polaribacter South of the sBdyACC. For microeukaryotes, Noelearhabdaceae, Phaocysteaceae, and Telonemia discriminated the same three zones. Network analysis suggests different prokaryote/microeukaryote interactions in each zone. In summary, the strong oceanographic fronts of the SO shape microbial community distribution, with important implications regarding nutrient and geochemical cycling.

ICN2021_002

1436

The BICEP Array Replacement Tower (BART): Polar Infrastructure Development Supporting Cosmic Microwave Background Research

Dr. Benjamin Schmitt

University of Pennsylvania, Philadelphia, PA, USA. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA

Abstract

Measurement of the polarized Cosmic Microwave Background (CMB) over the past few decades has enabled precision probes of the evolutionary history, composition, and dynamics of the primordial Universe. Next-generation CMB experiments will extend this scientific reach, allowing for tests of the inflationary theory of the early Universe, driven through constraints on the tensor-scalar ratio "r" via the search for primordial B-mode polarization. This includes the BICEP Array telescope program, which is targeting observation of B-modes at large angular scales, building on constraints already placed by the BICEP/Keck program. This talk will provide an overview of new infrastructure that is currently in development to ensure the sustainable extension of CMB research at the Amundsen-Scott South Pole Station - notably, the BICEP Array Replacement Tower (BART) project. BART is a straightforward evolution of existing infrastructure at the South Pole aimed at utilizing a limited footprint consistent with heritage facilities to extend experimental cosmology science operations at the South Pole. This discussion will highlight the current status of project design and fabrication, the opportunity for the deployment of a point-of-use photovoltaic energy system, and plans for future deployment. Finally, the talk will cover the lessons-learned from BART that can be applied to the broader development of scientific infrastructure operating at remote, high-altitude, low-temperature sites including in Polar environments and at sites in the Atacama Desert of Northern Chile, in line with current priorities of the global polar science community.

1437

TRIPLE-IceCraft – Electro-thermal drill to transport of scientific payloads for in-situ measurements in the ice and clean access to subglacial lakes

Clemens Espe¹, Jan Audehm², Jean-Pierre de Vera³, Marco Feldmann¹, Gero Francke¹, Mia Giang Do², Dirk Heinen², Fabian Schoettler¹, Christopher Wiebusch², Simon Zierke²

¹GSI - Gesellschaft für Systementwicklung und Instrumentierung mbH, Aachen, Germany. ²RWTH Aachen University Physics Institut III B, Aachen, Germany. ³Microgravity User Support Center (MUSC), Space Operations and Astronaut Training, German Aerospace Center (DLR),, Cologne, Germany

Abstract

Reaching and investigating water bodies beneath thick layers of ice is a major challenge. Whether it is subglacial lakes in the polar regions on Earth or the search for extraterrestrial life in our solar system. The TRIPLE project, initiated by the German Space Agency at DLR, is developing technologies for the exploration of such subglacial regions. This involves three main components: (i) A fast and retrievable melt probe for penetrating and analyzing the ice layer. (ii) A miniaturized autonomous underwater vehicle (nanoAUV). (iii) An astrobiological laboratory for the in-situ study of samples.

This contribution focuses on the development of the melting probe and discusses possible scientific instrumentations as a minimal invasive and clean access to study subglacial lakes. TRIPLE-IceCraft, the first prototype, for the technical feasibility was developed. It is designed for a drill depth of several hundred meters and a drilling velocity of 3-5 m/h. The probe includes a modular carrier system for transporting scientific payloads, with watertight pressure vessels, a winch module, and two melting heads equipped with electrothermal heating cartridges. Furthermore, the probe is retrievable since the cable is coiled inside the probe using an electric-motor-powered coil. The cable bears the weight of the probe and is additionally utilized for communication and power. To integrate arbitrary scientific payloads, payload modules with standardized interfaces for voltage supply and communication are provided.

During the 2023/24 Antarctic summer season, the TRIPLE-IceCraft melting probe was successfully tested on the Ekström Ice Shelf near the German research station Neumayer-Station III. A camera was integrated as scientific payload. As part of the test campaign, all systems were tested and several boreholes were drilled, the deepest of which was 52 m. During the tests, the probe demonstrated full capability to return to the surface solely using its own cable.

1439

Belgium at the Science-Policy interface in the Antarctic Treaty System: creation of a protected area for environmental and scientific values

Dr Annick Wilmotte¹, Dr Quinten Vanhellemont², Dr Valentina Savaglia^1,3,4, Mr Sam Lambrechts³, Prof. Anne Willems³, Prof. Elie Verleyen³, Dr Bjorn Tytgat³, Prof. Wim Vyverman³

¹University of Liège, Liège, Belgium. ²Institute of Natural Sciences, Brussels, Belgium. ³University of Ghent, Ghent, Belgium. ⁴University of Sevilla, Sevilla, Spain

Abstract

The Protocol on Environmental Protection of Antarctica designates this continent as a “natural reserve, devoted to peace and science”. Its Annex V describes the creation process of a network of ‘Antarctic Specially Protected Areas’ (ASPAs), and lists the values that the Parties to the Protocol should aim to protect, including outstanding environmental, scientific, historic, aesthetic or wilderness values.

Since 2009, Belgium operates a research station, Princess Elisabeth, in a mountainous inland region of Dronning Maud Land, East Antarctica, where air temperatures are always [SV1] negative. Most of the existing life forms are microbial, except few nesting birds (snow petrels and skuas), and are restricted to terrestrial microhabitats with suitable conditions (exposition to the sun, sheltering from katabatic winds, meltwater, stable bedrock). Thanks to the BelSPO projects ANTAR-IMPACT, BELDIVA and MICROBIAN, Belgian and international scientists have studied the molecular diversity, biogeography, and ecology of the prokaryotes and microeukaryotes in the soils, biofilms and crusts and started experimental work to mimic the impacts of climate change. A high biodiversity of microorganisms and invertebrates was observed, with endemic taxa, as well as large differences in communities geographically close but growing on different substrates. The need to protect the biological communities from anthropogenic disturbances, introduction of microbial taxa from other regions or other sites in the region, trampling and oversampling has driven the initiative of Belgium to propose a multi-site Antarctic Specially Protected Area (ASPA 197) in parts of the Eastern Sør Rondane Mountains (71°50’-72°S; 22°50’-23°50’E) including 7 ice-free areas. The ASPA site and its Management Plan were adopted in 2023: https://www.ats.aq/devph/en/apa-database/197.

1440

A mineral magnetic approach to reconstruct the marine-lacustrine transition phase from an East Antarctic Lake

Dr Anish Kumar Warrier¹, Mr Joju George Sebastian¹, Dr Mahesh Badnal², Ms Yamuna Sali A.S.¹, Mr Aviraj Singh², Dr Rahul Mohan²

¹Manipal Academy of Higher Education, Udupi, India. ²National Centre for Polar and Ocean Research, Vasco, India

Abstract

In this study, we present the environmental magnetic properties of a sediment core spanning the past 6.37 cal ka B.P. obtained from Stepped Lake, a coastal lake in Larsemann Hills, East Antarctica. The magnetic mineralogy is dominated by magnetically soft ferrimagnets. The lake was previously reported to be under marine influence during the mid-late Holocene and therefore based on diatom analyses, the core was divided into 3 zones. In zone 1 (6.37-3.07 cal ka BP), marine diatoms were dominant indicating that the lake was submarine. Magnetic concentration-dependent parameters c_lf, c_ARM, and SIRM show higher values, indicating colder conditions in the region. Magnetic grain size-dependent parameters, c_ARM/SIRM and c_ARM/c_lf show low values during this period, indicating the dominance of coarse magnetic grains. In zone 2 (3.07-1.75 cal ka BP), a mixture of marine and lacustrine diatoms is present suggesting that zone 2 represents a transition zone between marine and lacustrine conditions. c_lf, c_ARM, and SIRM can be seen reducing into zone 2. c_ARM/SIRM and c_ARM/c_lf also show an increasing trend during this period, indicating warmer conditions and finer magnetic grain sizes as compared to Zone 1. Zone 3 (1.75-0.25 cal ka BP) is marked by the dominance of lacustrine diatoms and represents a shift in the environmental conditions from marine to lacustrine. The values of c_lf, c_ARM, and SIRM show a sharp decrease, suggesting a shift to warmer conditions in the region. The magnetic grain size-dependent parameters c_ARM/SIRM and c_ARM/c_lf can be seen increasing into Zone 3, reflecting finer magnetic grain sizes. Between ~1.0 and 0.7 ka B.P. a pronounced decrease can be observed in the values of c_lf, c_ARM, and SIRM. This observation indicates a warming trend in the lake catchment during this period, coeval with the Medieval Climate Anomaly.

1442

Warming the Deep: visualizing Antarctic overturning circulation slowdown through printmaking

Skye Moret^1,2, Matthew Letzelter²

¹Northeastern University, Boston, USA. ²Willamette University, Portland, OR, USA

Abstract

As scientific evidence for the slowdown of Antarctic overturning circulation continues to mount, there is increasing need to visualize and share this urgent issue with an expanded, interdisciplinary audience. The majority of vertical ocean circulation discourse is exchanged within the form of academic texts and figures, offering few visual artifacts to engage the public with its drivers and ominous regional and global impacts. With the intention to visually reveal and review the components of an ocean phenomenon so hidden from communal discourse, we made a series of eight woodblock prints called ‘Warming the Deep.’ The series specifically explores four themes: the drivers and direct impacts of Antarctic overturning circulation slowdown, its impacts on food webs, the consequent effect on carbon dioxide uptake, and compounding feedback loops including ice sheet melt acceleration and sea level rise. The affordances of printmaking in the context of semi-global ocean circulation collapse are ample: visual rhetoric and aesthetics can articulate key compelling scientific insights, visual encoding of ocean dynamics can employ emotional qualities and rational form using enunciative and semiotic design considerations, and the use of a traditional, tangible, and reproducible media is an accessible way to approach awareness and understanding of a complex Antarctic issue. The combination of printmaking and Antarctic science brings to the public a renewed critical environmental consciousness that not only employs, but respects and illuminates the most valuable qualities of both science and art.

1444

The Ocean’s Role in Driving Antarctic Sea-Ice Changes, a Data/Model Investigation

Sharon Stammerjohn^1,2, Mike Dinniman³, Michael Cappola⁴, Carlos Moffat⁴, Ted Maksym⁵

¹Institute of Arctic and Alpine Research (INSTAAR), Boulder, USA. ²University of Colorado, Boulder, USA. ³Old Dominion University, Norfolk, USA. ⁴University of Delaware, Newark, USA. ⁵Woods Hole Oceanographic Institution, Woods Hole, USA

Abstract

Antarctic sea ice extent has exhibited recent remarkable and puzzling change, with record maxima in 2013-2015 followed by an Antarctic-wide abrupt sea-ice decrease in 2016 that continues to persist, with new consecutive record low sea ice observed in both 2022 and 2023. If this shift to reduced Antarctic sea-ice continues, it will have far-reaching implications both globally (ocean heat and carbon sequestration, sea-level rise) and regionally (ocean productivity, biogeochemical cycles, marine ecosystems). The recent reduced Antarctic sea-ice changes suggest a possible shift in the ocean, which is nonetheless difficult to assess given limited winter ocean observations within seasonal sea-ice zones. However, the west Antarctic Peninsula (WAP) region now has 28 years (1993-2020) of summer ocean observations made available by the Palmer Long-Term Ecological Research program, which can be used in tandem with satellite remote sensing observations of sea ice and an eddy-resolving ocean process model to investigate the ocean’s role in driving winter sea-ice changes. Through this data/model synthesis, we will test whether persistence in upper ocean thermal and/or stratification anomalies could drive longer-lasting ice-ocean anomalies from summer into autumn (e.g., ~Jan-May), or the re-emergence of ice-ocean anomalies in autumn (~Apr-Jun) as imparted in the previous spring (~Oct-Nov). Ocean persistence partially depends on the depth and heat content of the winter water layer and the strength of stratification at its base, and these factors will be assessed under different forcing conditions and on/offshelf ocean settings. In short, we will assess the degree of ocean persistence in driving Antarctic sea-ice variability and its subsequent effect on summer upper ocean properties as reported by Cappola et al (2024).

1446

Sea Ice as Modulator of Ocean-Ice Shelf Interactions

Sharon Stammerjohn^1,2, Pierre St-Laurent³, Ted Maksym⁴, Patricia Yager⁵, Robert Sherrell⁶

¹Institute of Arctic and Alpine Research (INSTAAR), Boulder, USA. ²University of Colorado, Boulder, USA. ³Virginia Institute of Marine Science, Gloucester Point, USA. ⁴Woods Hole Oceanographic Institution, Woods Hole, USA. ⁵University of Georgia, Athens, USA. ⁶Rutgers University, New Brunswick, USA

Abstract

Antarctica’s floating glacial ice shelves are focal points for grounded ice sheet export through calving and basal ice shelf melt. In the Amundsen Sea Embayment (ASE) there has been thinning of ice shelves and accelerated glacial losses, driven in large part by changes in the atmospheric and ocean circulation that in turn drive changes in the delivery of warm modified Circumpolar Deep Water to ice shelf cavities and grounding lines. The ASE is also distinguished by the Pine Island and Amundsen Sea polynyas, two areas of very high sea-ice production rates. These two polynyas are separated and heavily influenced by the Thwaites Glacier Tongue and its northward extension of icebergs cemented together by fast ice. This partially grounded northward ice obstruction is a physical barrier to both surface air-sea interactions and to ocean and sea ice circulation. While it has been shown that the marine icescape (inclusive of seasonal and multiyear sea ice, fast ice, and grounded and drifting icebergs) plays an important buttressing role in the stability of Antarctic ice shelves, here we investigate how the marine icescape in the ASE might also modulate ocean circulation and ocean heat delivery to ice shelf cavities. In this presentation, we address the role of seasonal sea-ice in driving variability in sea ice-ocean interactions and subsequently, ocean-ice shelf interactions in the ASE. For this analysis, we combine satellite observations of sea ice, ocean observations (including oxygen isotopes) from the ASE, and output from a regional 3D sea ice-ice shelves-ocean model to investigate the role of sea ice as modulator of ocean-ice shelf interactions. In a companion study (St-Laurent et al, 2024), the role of icebergs, ice tongues, and fast ice in modulating ocean-ice shelf interactions are additionally evaluated.

1449

Unraveling Antarctic Geopolitics: Who Shapes the Narrative on Conservation?

Dr. Cristian Lorenzo^1,2, Dr. Fernando Estenssoro³, Dr. Ana Seitz⁴

¹(1) Centro Austral de Investigaciones Científicas (CADIC) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ushuaia, Argentina. ²(2) Instituto de Ciencias Polares, Ambiente y Recursos Naturales (ICPA) – Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur (UNTDF), Ushuaia, Argentina. ³(4) Instituto de Estudios Avanzados (IDEA) – Universidad de Santiago de Chile (USACH), Santiago, Chile. ⁴(3) Instituto de Investigaciones en Ciencias Sociales (IDICSO) – Universidad del Salvador (USAL) / Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina

Abstract

Antarctic geopolitics frequently adopts a statocentric viewpoint, in which diplomats advocate for the representing nations categorized as Consultative or Non-Consultative Parties within the Antarctic Treaty framework while navigating the complexities of Antarctic governance. Their efforts towards the Antarctic Treaty System have been widely recognized. Additionally, science in the Antarctic region is a synonym for cooperation and provides insights for policymakers, informing decisions about preservation, conservation, and management. However, it is crucial to consider underexplored facets of Antarctic geopolitics. By situating the analysis at the domestic level, we want to draw attention to shared patterns and processes that might be missed in approaches to Antarctic geopolitics at a macro level of analysis. The source for this study draws on articles, reports, policy briefs, blog posts, opinion pieces, editorials, and audiovisual materials from non-governmental institutions (think tanks and environmental organizations) based in the United States and the United Kingdom. The study examines the period between 2016 and 2023, starting with the establishment of the Marine Protected Area in the Ross Sea by the Commission for the Conservation of Marine Living Resources in 2016 and ending with the Antarctic Treaty Consultative Meeting held in Helsinki (Finland) in 2023. We focus on the representations of challenges in the Antarctic region conservation, the concepts frequently used to frame their narratives, and how they think of possible solutions. Within a framework of discussion about politics and nature in Antarctica, this conference presentation seeks to shed light on the comprehension of connections between narratives on the conservation of nature in the Antarctic region and the representation of geopolitical interests.

1451

Snow isotopic composition at Vostok is dominated by summer temperature due to post-depositional modification

Alexey Ekaykin, Irina Alekhina, Anna Kozachek, Kirill Tchikhatchev, Natalia Tebenkova, Arina Veres, Vitaly Zarovchatsky

Arctic and Antarctic Research Institute, Saint Petersburg, Russian Federation

Abstract

An extensive dataset on isotopic composition of atmospheric precipitation, upper snow surface, atmospheric water vapor, as well the results of laboratory and field experiments is used to study the post-depositional changes in snow isotopic composition at Vostok Station (central East Antarctica). It is shown that the post-depositional processes, caused by diurnal cycle of moisture flux from atmosphere to snow and back, occur in summer season (December and January) and span the upper 15-20 cm of the snow thickness. Each annual stratum spends on average 2.5 years in this active layer of snow, during which period the deuterium concentration is increased by about 18 per mil, while the changes in deuterium excess are uncertain. Due to this, the initial temperature signal of the atmospheric precipitation’s isotopic composition is fully modified and replaced by a secondary signal related to the summer snow surface temperature. Possible implications for the deep ice core isotopic composition interpretation is discussed. The work is supported by Russian Science Foundation.

1453

Antarctic Law: A concept seeking for a comprehensive definition

Prof. Dr. Luis Valentín Ferrada

Universidad de Chile, Santiago, Chile. Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile

Abstract

Human activities in Antarctica and the surrounding seas are under the law. It is essential to ensure that the objectives established by the international community and the individual states concerning that area are met. This set of such legal rules and principles is called “Antarctic law”, the same name given to the academic discipline that studies it. The source of its norms is international law, but also domestic law. They cover a wide range of subjects and different sorts of legal rules. Although there have been domestic rules on Antarctica since the mid-19th century, and an international regime has been in place since the second half of the 20th century, there are not enough studies that attempt to understand this set of rules as a whole. Most academic work about Antarctic law only focuses on an international law perspective and considers the Antarctic Treaty System as something isolated. This presentation proposes and discusses a comprehensive definition of Antarctic law, analysing its complexity and revising the categories of rules considered. It seeks to give order and coherence to the norms that apply in the southern latitudes. We will review the rules of public international law in a broader sense, as well as those of domestic law, the issues of exercising jurisdiction, conflict of law and comparative legal studies. The possible integration of Antarctic law as part of polar law will also be analysed. The identification and precision of these categories of legal norms is a significant step forward in promoting their study coherently and orderly. It is an intellectual task essential for a better understanding of Antarctic governance. Knowing which rules govern human activities on the sixth continent and how they are interrelated and ordered will promote its better management.

1456

Ionospheric Plasma Irregularities in the Polar Regions

Prof. Wojciech Miloch, Gaute Holen, Daria Kotova, Yaqi Jin, Rinku Mishra, Nicholas Ssessanga

Department of Physics, University of Oslo, Oslo, Norway

Abstract

Geomagnetic activity controls to a large degree the dynamics of ionospheric plasma. In the polar regions the ionosphere is directly coupled to the magnetosphere and space plasma, and this dynamic coupling often is maninfested in plasma instabilities and turbulence. The resulting plasma irregularities impact the propagation of trans-ionospheric radio waves and can lead to scintillations in the received signal. Consequently, they can degrade communication or positioning with the Global Navigation Satellite Systems (GNSS), such as GPS or Galileo. Thus, ionospheric plasma irregularities at high latitudes are important aspects of the space weather system and their understanding is crucial for modeling of the state of the ionosphere and building capability for predicting and mitigating severe space weather effects in the polar regions.

We present recent case and statistical studies on plasma irregularities in the polar regions with the focus on Dronning Maud Land in Antarctica, but also in the context of interhemispheric studies with in-situ and remote measurements by sounding rockets and satellites. We consider the role of auroral particle precipitation and demonstrate that the strongest plasma irregularities can be related to the edges of the auroral oval. Results from recent climatological studies of the occurrence of irregularities and plasma variability based on the satellite data are also presented in the context of the space weather effects observed with the ground-based instruments. Finally, we discuss our ongoing initiatives which aim at developing models and forecasting services for the space weather effects in the polar regions, their status, challenges, and prospects.

Acknowledgments

This work has been supported by the European Union's Horizon 2020 research and innovation programme (ERC Consolidator Grant agreement No. 866357, POLAR-4DSpace).

1457

Bridging Polar Science and Public Engagement: Assessing the Impact of APECS Brazil's Initiatives

Raphael Fernandes Vieira¹, Dr Maria Jimena Cruz², Dr. Stephan Machado Dohms³, MSc Anna Beatriz Oaquim⁴, MSc Guilherme Afonso Kessler⁵, Dr Júlia Grohman Finger⁶, MSc Júlia Lorenz⁷, Dr Paola Barros Delben⁸

¹Universidad Nacional de La Plata (UNLP, Brazil), La Plata, Argentina. ²Multidisciplinary Institute of History and Human Sciences (IMHICIHU, Argentina), Buenos Aires, Argentina. ³Universidade Católica de Brasília (UCB, Brazil), Brasília, Brazil. ⁴Universidade do Estado do Rio de Janeiro (UERJ, Brazil), Rio de Janeiro, Brazil. ⁵Universidade Federal do Pampa (UNIPAMPA, Brazil), Bagé, Brazil. ⁶Associação de Pesquisadores Polares em Início de Carreira (APECS, Brazil), Porto Alegre, Brazil. ⁷Universidade Federal de Rio Grande do Sul (FURG, Brazil), Rio Grande, Brazil. ⁸Universidade Federal de Santa Catarina (UFSC, Brazil), Florianópolis, Brazil

Abstract

The Association of Polar Early Career Scientists (APECS) is a global organization committed to nurturing emerging leaders in Polar Science and Education while fostering connections among researchers worldwide. Central to APECS's mission is the dissemination of knowledge, with a specific emphasis on bridging the gap between Polar Research and the general public. This endeavor is achieved through a range of activities coordinated by each APECS's National Committees. Each of these committees are composed of polar researchers from different disciplines, stages in their research career and parts of their country, resulting in a very diverse and heterogeneous group of researchers.

This presentation aims to assess the contribution of the Brazilian National Committee of APECS towards making polar science more accessible to a broader audience. We will discuss several initiatives and efforts undertaken in recent years to enhance communication and accessibility in an inclusive manner. In order to do this, we will consider some examples of these initiatives. Initially, we will discuss the efforts and challenges that involve editing a journal containing information about polar research in an accessible language. Next, we will reflect on our experiences of establishing partnerships with affiliated APECS entities to extend our outreach beyond Brazil. Additionally, we will explore the organization of symposiums and events featuring simultaneous translation, which serve to democratize participation and ensure that polar research reaches everyone. Furthermore, we will delve into the organization of the International Polar Week (SPI), where we actively engage with educational institutions to connect with younger generations, thereby amplifying APECS's impact.

Through these initiatives and collaborative efforts, we aim to demonstrate that by fostering a deeper understanding and appreciation of polar science among diverse audiences, we can significantly advance our goal of promoting greater accessibility and inclusivity in polar science on a global scale.

1459

Confronting discrepancies between observed and simulated seasonal and regional Antarctic sea ice

Laura Landrum, Marika Holland, Alice DuVivier

National Center for Atmospheric Research, Boulder, USA

Abstract

Annually the Antarctic sea ice expands and contracts over an enormous range - gaining and losing roughly 15 million km² every year. In addition, satellite records of Antarctic sea ice concentrations show small yet significant increases in all seasons from 1979-2016 followed by record lows in 2022 and again in 2023. Climate model simulations of Antarctic sea ice are most often assessed on the basis of whether or not they adequately capture the climatology and trends of the integrated southern hemisphere (SH) sea ice extent (SIE) compared with those based on the satellite observations.

CMIP5 simulations of Antarctic Sea Ice were deemed of “low confidence” in the Intergovernmental Panel on Climate Change AR5 report due to extreme inter-model spread and overall inability of many models to adequately reproduce the mean, variability and trends in Antarctic sea ice seen in the observations (Collins et al., 2013). CMIP6 simulations show only small improvements, and the intermodal spread in annual mean cycle of Antarctic Sea Ice remains substantial (Roach et al., 2020). Several models simulate the observed climatology of SH SIE, yet they struggle to capture the observed trends.

Integrated SH SIE obscures the high regional and seasonal variability of Antarctic sea ice and sea ice trends. Antarctic sea ice trends, for example, differ not only in magnitude but also in sign in different regions and seasons. Curiously, climate models fail to capture the strong positive trends in sea ice in the Ross Sea, particularly during austral fall.

In this work we highlight model-observations Ross Sea ice discrepancies that persist across different models and model configurations and explore possible contributing mechanisms. We discuss possible implications for modeling support of the Ross Sea Marine Protected Area (MPA) monitoring and understanding.

1460

Digital science communication from Antarctica and Punta Arenas: Connecting with new audiences through transmedia storytelling and social media

Constanza Barrientos^1,2, Nadia Politis³, Elie Poulin³, Julieta Orlando³, Víctor Fajnzylber⁴

¹BASE Millennium Institute of Biodiversity of Antarctic and Subantarctic Ecosystems, Punta Arenas, Chile. ²Antarctic Youth Coalition Foundation, Punta Arenas, Chile. ³BASE Millennium Institute of Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago, Chile. ⁴FCEI: Faculty of Communication and Image Universidad de Chile, Santiago, Chile

Abstract

Chileans are increasingly informed by Social Medias, instead of the Media, reveals the latest "Digital News Report" of the Reuters Institute of the University of Oxford (2023). This change of habit highlights the need to adapt the communication of Polar Science to new formats and languages, a task that allows scientific journalism and work teams knowledgeable of the new trends. A challenge that has been developed by the BASE Millennium Institute through Instagram campaigns such as "This is my science", and the "Antarctic Metaverse" project.

The Science Communication campaigns on Instagram have allowed reaching a wider audience, with emphasis on women aged 18-30 years, increasing by more than 4.000 followers in a few weeks, with videos of more than 260 thousand reproductions. On the other hand, the "Antarctic Metaverse" project has developed an immersive space to communicate science, allowing users to interact with Antarctic science and its protagonists, in a virtual polar environment.

Can social networks and digital formats be effective tools for the communication of Antarctic knowledge? Are we facing passive users who receive knowledge, or do they demand greater spaces for interaction? Strengthening public awareness about Antarctic science, climate change and stories with a gender focus are part of the reflection that will be developed from the perspective of science journalism in Punta Arenas and Santiago at the height of the digital era.

1467

The microbial community assembly processes vary across time, space, and habitat, in Antarctic lakes.

PhD student Diego Ahumada^1,2, PhD Guillaume Schwob², PhD Julieta Orlando^1,2, PhD Lea Cabrol^2,3

¹University of Chile, Santiago, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ³Aix Marseille University, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France

Abstract

Antarctic ecosystems are affected by global warming at a faster and more intense rate than lower latitudes, leading to an expected increase of the number and surface of Antarctic lakes, considered as sentinels of climate change. Due to their crucial ecological roles, especially regarding greenhouse gas cycling, it is of prime importance to understand the assembly processes of lake microbial communities. Microbial assembly processes have been mainly evaluated from a spatial and environmental perspective so far. However, assessing the temporal dynamics of microbial assembly processes is still rare and challenging.

In this study, we examined the spatial and temporal dynamics of prokaryotic communities’ assembly in Antarctic lakes. Over four field campaigns during austral summers from 2017 to 2023, we collected 164 samples of water and sediment from 11 lakes in the Fildes Peninsula, King George Island, Maritime Antarctica. Bacterial communities were analyzed by sequencing the V4-V5 region of the 16S rRNA gene (Illumina MiSeq).

We observed that the main differences lie in the comparison between habitats, which exhibit distinctive prokaryotic community structures. In water habitat, physico-chemical variables such as temperature and organic matter play a key role in the variation of the prokaryotic community. Spatial dynamics (comparing lakes within the same year) had a greater impact than temporal dynamics (comparing years within the same lake) on community variation in both habitats. Sediment communities were characterized by a larger influence of dispersal limitation, while ecological drift was more important in water communities, consistently with the differential dispersal capacity of both habitats. Variable selection (i.e., environmental filtering) was the second dominant assembly process in both habitats, and its contribution increased when comparing different years in water. Investigating temporal changes in microbial community formation of Antarctic lakes provides a valuable baseline for understanding microorganisms' response to climate change.

1468

Improving Access to Climate Science Training: The World Climate Research Programme (WCRP) Academy and Climate and Cryosphere (CliC) Core Project

Dr Narelle van der Wel¹, Dr Edward Hanna², Dr Melissa Hart³, Dr Amy Lovecraft⁴, Dr Chris Lennard⁵, Dr Keith Alverson⁶, Dr Meghan Taylor⁶, Dr Ma. Laurice Jamero⁷, Ms Lora Batino⁷, Ms Anne-Lise Hadzopoulos¹

¹World Climate Research Programme, Geneva, Switzerland. ²University of Lincoln, Lincoln, United Kingdom. ³University of New South Wales, Sydney, Australia. ⁴University of Alaska Fairbanks, Fairbanks, USA. ⁵University of Cape Town, Cape Town, South Africa. ⁶CliC IPO, University of Massachusetts Amherst, Amherst, USA. ⁷Manila Observatory, Manila, Philippines

Abstract

The WCRP Academy is the research training advisory and coordination arm of the World Climate Research Program. It is the flagship activity for WCRP´s mission: “to develop, share, and apply climate knowledge that contributes to societal well-being” and works to equip current and future climate scientists with the knowledge, skills and attributes required to tackle the world’s most pressing and challenging climate research questions. In this presentation, we will introduce the Academy and our catalogue of climate science training, which collates in-house WCRP training activities and educational materials to the global science community.

Together with the WCRP Climate and Cryosphere (CliC) Core Project, we will present some of the upcoming training and both new and ongoing research and outreach initiatives that relate to Antarctica. From a CliC perspective, this includes the Ice Sheet Model Intercomparison Project for CMIP7 (ISMIP7), sea-ice/ocean research initiatives, Expert Group on Ice Sheet Mass Balance and Sea Level (ISMASS) efforts, such as a recent workshop/publication on cross-timescale variability of the ice sheets and their sensitivity to climate forcing, and an envisaged Antarctic Report Card. We will explain how the community can contribute to these efforts, and invite expert groups, academic and research institutions, government agencies and non-government organizations who provide climate science training and education to register as training providers and contribute to the Academy online training catalogue.

1469

Troll Ionospheric Observatory in Dronning Maud Land, Antarctica

Prof. Wojciech Miloch, Daria Kotova, Jonas Birkeland Carlsen, Bjørn Lybekk, Espen Trondsen

Department of Physics, University of Oslo, Oslo, Norway

Abstract

The uppermost part of Earth’s atmosphere is partially ionized, and it is thus in the plasma state. In the polar regions it is directly coupled to interplanetary space. Here the solar wind energy is transferred into the upper polar atmosphere, which leads to dynamical processes such as aurora, ionospheric instabilities, and turbulence. The state of the ionosphere in relation to geomagnetic activity is a part of a larger space weather system. Space weather effects can impact man-made infrastructure both in space and on the ground. Studying space weather effects has thus both fundamental and applied aspects. For example, development of space weather models and forecasting services is of importance for safety and operations in the polar regions. As the southern hemisphere is characterized by more irregularities in the ionospheric plasma density than the northern hemisphere, there is a need for monitoring and studying space weather phenomena and effects over Antarctica.

One of space weather observatories that allow for studies of the equatorward part of the auroral oval, as well as of the subauroral Antarctic ionosphere is Troll Ionospheric Observatory. The observatory was established in 2018 at the Norwegian Research Station Troll in Dronning Maud Land. We present results obtained with the measurements from Troll and complementary datasets from Antarctica, and we demonstrate that the expanding auroral oval as well as subauroral ionosphere can be characterized by significant irregularities in the plasma density. We also discuss the operational status of the observatory, as well as ongoing works related to commissioning of new instrumentation in the next Antarctic seasons, which are within the framework of Troll Observing Network (TONe). Synergy effects with other ionospheric observatories in Antarctica and in the Arctic are also discussed.

1470

Antarctic cyanobacterial diversity in the BCCM/ULC collection as useful and sustainable resource for research

Ms Maria Christodoulou¹, Dr Marcelo Vaz¹, Ms Alina Lequeux², Ms Haifaa Savora¹, Dr Luc Cornet¹, Dr Annick Wilmotte^2,1

¹BCCM/ULC culture collection, Liège, Belgium. ²University of Liège, Liège, Belgium

Abstract

On the Antarctic continent, Cyanobacteria represent key primary producers. They build extensive benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting adaptations to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, desiccation and other stresses. The genetic mechanisms of this resistance only start to unravel.

The BCCM/ULC public collection presently includes 140 Antarctic cyanobacterial strains and its catalogue is available on https://bccm.belspo.be/catalogues/catalogue-search?collection=ULC. An ISO9001 certificate was obtained for the public deposition and distribution of strains.

The purpose of this collection is to gather a representative sample of Antarctic cyanobacterial diversity from different biotopes (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.) and make it available for researchers to study its diversity, evolution, ecophysiology, and genomic make-up. This is particularly important, considering the emerging use of metagenomic approaches on environmental samples, where the comparison with well-characterized strain genome sequences is very useful. As a small piece of natural samples is sufficient to isolate a large number of strains, culture collections are a sustainable option to provide access to microbial biodiversity without the environmental costs of field trips and cumulative sample collections.

Lastly, we carried out a genomic study of two BCCM/ULC Antarctic strains assigned to the recently established genus Laspinema. The phylogenomic analysis showed that these strains together with the strain FRX01, which were collected from lakes of the McMurdo Ice Shelf or Dry Valleys. represent a new Laspinema species. Interestingly, genome mining showed that the Biosynthetic Gene Clusters found in the Antarctic strains are less diverse compared to their temperate relatives. A search of the functional genes detected 115 specific genes for the Antarctic Laspinema genus, but no function could be attached to them (dark matter), showing the need for better genetic knowledge.

1471

Monitoring Highly Pathogenic Avian Influenza: what can be considered as a “sentinel” for infectious diseases in the sub-Antarctic islands?

Keltoum Boumedjane

École des Hautes Études en Sciences Sociales (EHESS), PHD in anthropology, Paris, France. Centre d’Écologie Fonctionnelle et Évolutive (CEFE), interdisciplinary research in ecology, Montpellier, France

Abstract

Is the sub-Antarctic a good sentinel for Highly Pathogenic Avian Influenza (HPAI) viruses?

From sentinel species to sentinel spaces, we will explore the relevance of these conceptual frameworks from an anthropological perspective, based on two fieldworks with French disease ecologists in the French Austral Territories (austral summer 2021) and in the Falklands/Malvinas (austral summer 2022).

The panzootic H5Nx HPAI arrived in the sub-Antarctic region during the austral summer 2023. First detected in South Georgia, it then reached the Falklands/Malvinas, with the presence of the virus confirmed on several islands of both archipelagos. In February 2024, the first cases of HPAI were detected on the Antarctic continent.

HPAI surveillance and management is implemented at different scales, ranging from targeted animal species, to communities of actors of surveillance, to ocean-scale territories. In the context of HPAI spread through the Southern Ocean, efficient surveillance should focus on specific animal species, people communities and territories identified as epidemiological sentinels.

At the animal species scale, species with high risks of exposure to the virus, and potentially essential roles in its subsequent spread, have the potential to be good sentinels. Because of their foraging habits, scavenging birds such as skuas (Stercorarius spp.) are at high risk of exposure to pathogens circulating in both their mammalian and avian prey.

At the people community scale, the role of non-scientific human activities in epidemiological surveillance is often neglected. Farmers and private landowners cohabitating with wildlife are at the forefront of suspicious case detection in the Falklands/Malvinas, and wide-spread tourism makes it possible to extend the formal surveillance perimeter all over the Southern Ocean.

At the territory scale, the notion of “sentinel territory” applied to sub-Antarctic islands for HPAI would benefit from being discussed in comparison with the notion of a “model territory”, or as an Antarctic sentinel.

1473

The importance of books in your language in Antarctic education

Reiner Canales, Andrea Peña, Pablo Ruiz, Camila Buvinic, Harry Díaz

INACH, Punta Arenas, Chile

Abstract

The Chilean Antarctic Institute (INACH) has increased its book production over the last eight years, diversifying the topics and audiences it addresses. These publications aim to make Antarctic knowledge derived from the most recent scientific publications available, especially to the educational system, in a format and language suitable for each audience.

This was motivated by several factors:

The growing scientific production of the Chilean Antarctic Science Programme.
The low number of books in Spanish on Antarctic topics indicated the need to produce material in this language.
English publications on Antarctica, especially on historical topics, do not usually include information on the role of the gateway countries to the White Continent and their contribution to polar exploration and scientific expeditions.
INACH's interest in producing publications to assist in the plan to include Antarctica in Chile's curriculum.

Among the most recent books are the following.

"Visual Encyclopaedia of Antarctica". A comprehensive and easy-to-read overview of Antarctica, with abundant graphic material.

"Antarctic Science in Figures". The third book in the In Figures collection now focuses on the contributions of Chilean Antarctic science to polar knowledge.

"Little Antarctic Encyclopaedia". A large-format children's book with infographics on the continent's natural history, the Southern Ocean, the cryosphere, fauna and flora of the present and past, ecology, women's participation, etc.

All these books are available for free download at www.inach.cl, and are being distributed in many school libraries in Chile.

1478

Application of the Antarctic Treaty System and its related agreements in Domestic Law: A Case Study

Cristián Arroyo

Universidad de Chile, Santiago, Chile. Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile

Abstract

It is not common for Antarctic International Law to serve as the basis for a final judgment, let alone its ratio decidendi. For this reason, the ruling in case RIT GR-09-00021-2019, brought before the Tribunal Tributario y Aduanero de la Región de Magallanes y Antártica Chilena (in English: Tax and Customs Tribunal of the Magallanes and Chilean Antarctic Region), represents an extraordinary instance of the application of the Antarctic Treaty System and its related agreements in the operative part of the judgment. However, litigation in this matter could be a symptom of a larger conflict between Antarctic Law and Domestic Law.

This work not only analyzes the judgment of a specialized tribunal in tax and customs matters in harmony with a regional treaty but also the acquiescence of the Appeal Court, which is less specialized but of higher authority, regarding this technical decision. Furthermore, it examines how the ruling addresses a problematic issue - who ultimately determines the nationality of goods extracted within the territory of the United Nations Convention on the Law of the Sea (UNCLOS) - but also undertakes interpretative and unifying work from the perspectives of International Law, Commercial Law, Administrative Law, and Civil Law; taking into consideration technical elements of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR).

1479

HPAIV H5N1 2.3.4.4 in South Polar Skuas (Stercorarius maccormicki) in James Ross Island, Antarctica

Benjamin Bennett¹, Barbara Berazay¹, Gabriela Muñoz¹, Naomi Ariyama¹, Lucas Kruger², Marcelo Gonzalez², Victor Neira¹

¹University of Chile, Santiago, Chile. ²Instituto Antartico Chile, Punta Arenas, Chile

Abstract

Highly Pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b was the causal agent of stranding and mass mortality events of marine mammals and seabirds throughout all Americas since 2021, reaching the subantarctic region in late 2023. On February 26^th, 2024, the first influenza H5N1 clade 2.3.4.4b case was reported in the Antarctic continent, in 2 skuas (Stercorarius spp) at Primavera Cape. A couple of days later, on February 26^th, 2024, an event of unusual mortality of avian species on James Ross Island was informed to the Chilean Antarctic Institute (INACH) by researchers of Mendel Czech Republic base. INACH - FAVETUCHILE surveillance team collected samples from five South Polar Skuas found dead near a lake (63°47’55.3236’’S, 57°48’31.8060’’W), within a radius of 80 meters from the GPS location point. Another group of Skuas without any visible clinical signs attributable to HPAI was observed within the area A total of 6 samples of brain, air sacks, trachea, and a lymphatic node were collected and deposited in sampling tubes with an inactivating viral transport medium.

All samples were processed at the Chilean scientific base “Professor Julio Escudero”. Several rt RT-PCR reactions were performed to confirm the presence of HPAIV H5N1 2.3.4.4. All 6 samples from the 5 individuals were positive for the virus, confirming the presence of the strain on James Ross Island and the western side of the Antarctic peninsula. This fact may indicate that the infection is spreading among Antarctic wildlife, which in turn may generate more stranding and mortality events. At the time of this abstract's submission, sequencing efforts to genetically delineate the virus discovered in Antarctica are underway.

Partially funded by INACH RT_08-21 and Fondecyt 121151

1480

The role of gut microbiome in ecological niche differentiation, enabling the coexistence of two Antarctic echinoid species in the same habitat

MSc. Mélanie Delleuze^1,2,3, Dr. Guillaume Schwob^1,3,4, Dr. Julieta Orlando^1,3, Dr. Bruno Danis², Dr. Elie Poulin^1,3, Dr. Léa Cabrol^3,5

¹Universidad de Chile, Santiago, Chile. ²Université Libre de Bruxelles, Brussels, Belgium. ³Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (MI-BASE), Santiago, Chile. ⁴Instituto de Ecología y Biodiversidad (IEB), Santiago, Chile. ⁵Aix-Marseille CNRS, IRD, Mediterranean Institute of Oceanography (M.I.O.), Marseille, France

Abstract

Under the deterministic coexistence model, species with almost identical ecological niches cannot coexist since their intense competition would lead to their competitive exclusion. Syntopic species (i.e. species that occur in the same place at the same time) can gradually forge niche separation to reduce interspecific competition for resources. Niche separation relies on different patterns of resource use, such as diet and micro-habitat selection that allow them to coexist. The gut microbiota plays critical roles in host health and physiological functions and can confer host-specific capacities to occupy niches that would not otherwise be available.

Abatus agassizii and Schizocosmus abatoides are two genera of irregular sea urchins that coexist in the Fildes Bay in King George Island, Antarctica. Both species are burrowing deposit-feeders, they live and feed in the same sediment and are exposed to the same environmental conditions. Our objective is to determine the role of gut microbiota in allowing these two sea urchins to coexist in the same habitat. We studied the taxonomic composition and potential functions of the total (DNA-based) and active (RNA-based) gut microbiota through 16S rRNA gene sequencing (Illumina MiSeq), comparing the permanent and transitory fractions of the gut microbiota and the external sediment microbiota. Our results showed that although there was no discernible difference in the transitory gut microbiota between the two sea urchin species, A. agassizii and S. abatoides presented a significantly different permanent microbiota both in terms of composition, relative abundances, activity and predicted metabolic functions. Different bacterial phyla with distinct metabolic functions characterized the gut tissue microbiota of each sea urchin species.

These results suggest that specific gut bacterial lineages with differential metabolism might utilize environmental resources differently, providing a way to separate ecological niches between both species and allowing their coexistence in Fildes Bay, King George Island.

1481

40Ar/39Ar geochronology and geochemistry of Paulet Volcano: insights into the tectonic setting at the eastern Antarctic peninsula

Dr Luis E. Lara^1,2, Dr. Javier Reyes³, Mr. Diego González⁴

¹Universidad Austral de Chile, Valdivia, Chile. ²Instituto Milenio Ckelar Volcanes, Antofagasta, Chile. ³Independent Researcher, Santiago, Chile. ⁴Strabag-Zublin, Santiago, Chile

Abstract

Quaternary volcanism in the Antarctic peninsula is mostly located along the Bransfield strait and the Shetland islands. However, scattered stratovolcanoes have been recognized further southeast forming some alignments from what some rift systems have been inferred (Larsen and Prince Gustav rifts). Existence of the latter would be relevant to the present lithospheric structure and might be exerting control on the petrogenesis and magma ascent. However, the geophysical nature of these structures is not well understood, and the geochemical signature of the magmas still poorly constrained. We here report both 40Ar/39Ar geochronology and geochemical/isotopic data to show that Paulet Volcano erupted primitive alkaline magmas without a subduction signature during the Late Pleistocene and Holocene. The origin of these trachybasalts is related to an enriched mantle source with an OIB-like signature, similar to that of the James Ross Island Volcanic Group, comparable to that observed in the rear-arc domain of subduction systems, without need of a continental lithosphere involvement. Reappraisal of published geophysical data show that regional features can be reproduced without such a large-scale tectonic structures.

1483

Subglacial groundwater flow modulates the geothermal heat flux into the Antarctic Ice Sheet

Fiona Clerc, Jonathan Kingslake, Jacky Austermann, Roger Buck

Lamont-Doherty Earth Observatory, Palisades, NY, USA

Abstract

The flow of heat from the solid Earth to the base of the Antarctic Ice Sheet is a key boundary condition governing its evolution. Basal heat flow generates meltwater and lubricates the ice bed, allowing it to slide, but must be inferred from geophysical measurements of crustal or mantle temperatures. If subglacial groundwater is abundant in sedimentary basins found beneath the ice sheet, the convection of this groundwater may redistribute heat. We model the transport of heat by the flow of groundwater in subglacial sedimentary basins, and explore the conditions under which the heat flow felt by the base of the ice sheet differs from the geothermal heat flow inferred geophysically. We predict that in areas of high geophysically-inferred GHF, such as within the West Antarctic Rift System, the heating of groundwater at depth leads to density reductions in groundwater which are large enough to induce convection. The presence of widespread thermal convection cells implies important spatial and temporal variability in the heat flow felt by the ice sheet. Further, we model the effect of these convection cells on crustal temperatures. We find that over long timescales, thermal convection cools the upper crust, biasing downwards GHF maps derived from magnetic observations of the Curie depth. Finally, we consider the influence of ice sheet topography on horizontal heat advection. We find this effect is maximized at the ice sheet margins, and compare our predictions to heat flow measurements along the Antarctic continental shelf. In summary, we illustrate the complexity with which subglacial groundwater flow modifies the heat flux at the ice sheet base, and place into context geothermal heat flux measurements both at the continent- and local-scale at the ice sheet margin.

1486

INCREASED TEMPERATURES HAMPER THE ACUTE STRESS RESPONSE IN THE MARBLE ROCKCOD Notothenia rossii BY REDUCING INTERRENAL SENSITIVITY

Pedro M. Guerreiro^1,2, Sandra Silva¹, Bruno Louro¹, Alexandra Alves^1,3, Elsa Couto¹, Adelino V.M. Canario^1,2

¹CCMAR - Center of Marine Sciences, University of Algarve, Faro, Portugal. ²PROPOLAR - Portuguese Polar Program, Lisbon, Portugal. ³Yas SeaWorld Research & Rescue, Abu Dhabi,, UAE

Abstract

Temperatures in the Antarctic Ocean fluctuate between -1.9°C and 2°C. Antarctic fishes evolved in stable thermal conditions for over 20 million years, displaying structural and functional features resulting from adaptation or inherited from resilient ancestral species. Their ability to respond to increased temperature is uncertain. We aimed at evaluating the mechanism and capabilities of the HPI axis in the Antarctic fish Notothenia rossii in three sets of experiments.

Firstly we addressed the function of HPI using drugs involved in blockage or stimulation of cortisol release/action (saline, cortisol, dexamethasone, metyrapone, spironolactone, mifepristone) in fish kept at control or transferred to 6ᵒC. We then evaluated the amplitude and duration of the cortisol stress response following 4 groups of fish upon a standard stress test (SST: chasing + netting +1min air exposure). Finally, we tested the effects of prolonged thermal stress on the cortisol release in vivo and interrenal sensitivity in vitro, in fish acclimated to 2,5,8ᵒC for 10-days, before or after a SST.

After SST cortisol peaks between 1-4 hours and reduces to basal between 24-48 hours. Temperature influenced the cortisol response to SST. At higher temperatures cortisol levels in non-stressed group are as high as in fish subjected to SST. Interrenal sensitivity at high temperature showed little response to ACTH, suggesting low sensitivity and/or exhaustion, paralleled by changes in gene expression. Manipulation of the HPI-axis showed these fish to respond in a way similar to what has been reported in other fish families in temperate or tropical environments.

Supported by FCT grants PTDC/BIAANM/3484/2014 and UIDB/04326/2020. PROPOLAR-Programa Polar Português, project FISHWARM

1491

The scalar challenges of visually communicating Antarctic and Southern Ocean information

Skye Moret

Northeastern University, Boston, USA

Abstract

Current public mental models of climate-impacted ecosystems such as Antarctica and the Southern Ocean are constrained and influenced by information designed by communication professionals. Though design professionals are often commissioned to visualize these specific data stories, their expository content typically focuses on large regional or global geographic scales, disregarding potentially more emotionally engaging strategies at both smaller and temporally diverse scales. Likewise, formats of designed information range from domain expert-focused publications that communicate scientific measurements to human-centered design engagement for non-specialists that utilizes aesthetics and narrative to create salience and empathy. As design researchers and public engagement practitioners, it is critical that we begin to interrogate what specific information design affordances are being utilized, and at what scale, to advance Antarctic dialogue with a more cognitively intentional and human-centered approach. By encouraging information designers to examine where design can and should intervene to fill visualization gaps in the space of Antarctic and Southern Ocean knowledge exchange, this presentation offers a robust theoretical framework to produce more viscerally engaging visual communication at scales that matter to non-specialists.

1493

Patterns of genomic divergence during adaptive speciation and future projections in gentoo penguins.

Dr. Daly Noll^1,2,3,4, Dr. Jane Younger⁵, Dr. Luis R. Pertierra⁶, Dr. Michelle Greve⁶, Msc Eduardo J. Pizarro^2,3,4, Dr. Fabiola Leon^2,3,4, Dr. Debora Y. C. Brandt⁷, Dr Joshua Tyler⁸, Dr. Gemma Clucas⁹, Dr. Hila Levy¹⁰, Dr W. Brian Simison¹¹, Dr. Julie McInnes⁵, Dr. Pierre Pistorius¹², Dr. Céline Le Bohec^13,14,15, Dr. Francesco Bonadonna¹⁵, Dr. Phil N. Trathan¹⁶, Dr. Andres Barbosa¹⁷, Dr. Andrea Raya Rey^18,19,20, Dr. Gisele P.M. Dantas²¹, Dr. Rauri Bowie²², Dr. Elie Poulin^2,1, Dr. Juliana A. Vianna^2,3,4

¹Facultad de Ciencias, Universidad de Chile, Santiago, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ³Millennium Institute Center for Genome Regulation (CRG), Santiago, Chile. ⁴Laboratorio de Biodiversidad Molecular, Pontificia Universidad Católica de Chile, Departamento de Ecología, Facultad de Ciencias Biológicas, Santiago, Chile. ⁵Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia. ⁶Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa. ⁷Department of Integrative Biology, University of California, Berkeley, USA. ⁸Milner Centre for Evolution, University of Bath, Claverton Down, Bath, United Kingdom. ⁹Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, NY, USA. ¹⁰Office of Science and Technology Policy, Washington, DC, Chile. ¹¹Center for Comparative Genomics, California Academy of Sciences, San Francisco, USA. ¹²Centre of Excellence at the Percy FitzPatrick Institute for African Ornithology (11DST/NRF), Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa. ¹³Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France. ¹⁴Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco City, Monaco. ¹⁵CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Montpellier, France. ¹⁶British Antarctic Survey, Cambridge, United Kingdom. ¹⁷Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain. ¹⁸Centro Austral de Investigaciones Científicas – Consejo Nacional de Investigaciones Científicas y Técnicas (CADIC-CONICET), Ushuaia, Argentina. ¹⁹Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina. ²⁰Wildlife Conservation Society, Buenos Aires, Argentina. ²¹PPG in Vertebrate Biology, Pontificia Universidade Católica de Minas Gerais, Belo Horizonte, Brazil. ²²Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, USA

Abstract

One of the great challenges that must be faced in the climate change scenario is to be able to determine the adaptive potential of species. Species that show low signs of genetic diversity will be less likely to respond to future changes in their local environments and will therefore be at greater risk of extinction. In recent years, high levels of genetic divergence have been detected among gentoo penguins from distant regions, recording four evolutionary lineages distributed throughout the Southern Ocean. In this work, the complete genomes of 64 penguins were resequenced, and the degree of differentiation of the genomes was considered to answer different evolutionary questions. As we expected, high levels of neutral and adaptive differentiation were found between the genomes of penguins from distant colonies, suggesting that the 4 lineages have followed their evolutionary course in isolation and adapted to the climate and ecological conditions of their local habitats, identifying genes that favor their persistence in different environments of the Southern Ocean. Furthermore, our results suggest that the four gentoo penguins have different adaptive potential as a consequence of natural selection and historical processes that are reflected in the contrasting trajectories of their population sizes. The results of this work provide consideration for IUCN to locally assess the threats and potential risk of extinction of some of the gentoo penguin lineages.

1499

WILL PHOTOPERIOD AND TEMPERATURE ASYNCHRONY AFFECT THE PHYSIOLOGY OF THE ANTARCTIC SPINY PLUNDERFISH Harpagifer antracticus?

Pedro M. Guerreiro^1,2, Kurt Paschke^3,4,5, Daniela Nualart^6,7,5,4, Rita Costa¹, Joao Brazao¹, Adelino V.M. Canario^1,2, Stephen D. McCormick⁸, Luis Vargas-Chacoff^7,5,4

¹CCMAR - Center of Marine Sciences, University of Algarve, Faro, Portugal. ²PROPOLAR - Portuguese Polar Program, Lisbon, Portugal. ³Institute of Aquaculture, Universidad Austral de Chile, Puerto Montt, Chile. ⁴FONDAP Research Center: Dynamics of High Latitude Marine Ecosystems (IDEAL), Punta Arenas, Chile. ⁵Millennium Institute Biodiversity of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile. ⁶PhD Program in Aquaculture Sciences, Universidad Austral de Chile, Puerto Montt, Chile. ⁷Institute of Marine and Limnological Sciences, Universidad Austral de Chile, Valdivia, Chile. ⁸Department of Biology, University of Massachusetts, Amherst, USA

Abstract

Antarctica is characterized by rapid and extreme changes in daylight hours, also known as photoperiod, with winters with practically no light and summers with almost no night. Changes in daylight duration are a trigger for physiological signals for animals, including those in water such as fish, and these signals are often taken in combination with environmental temperature. Indeed, the photoperiod and temperature are usually the main signaling cues to control seasonality, one having an absolute annual consistency and the other small oscillations within a large variation, that modulate endocrine cascades leading to change. Here we aimed to evaluate how changes in Antarctic summer/winter photoperiod associated to temperature regimes impact the physiology of fish Harpagifer antarcticus. The animals collected in early January were subjected to a summer photoperiod “20 hours of light and 4 hours of darkness” or to a winter photoperiod “4 hours of light and 20 hours of darkness”, while keeping normal summer temperature 2-3°C and high temperature 5-6°C, and sampled at 9, 18 and 36 days after the onset of experimental photoperiods. Results show differences in feeding intake and enzymatic activity between species and photoperiods, and that photoperiod induce small changes in CTmax and metabolic rates in H. antarcticus. This appears to confirm the hypothesis that photoperiod modifies the seasonal physiology of fish, although further experiments with combinations of daylight variations and winter temperatures are warranted. It also remains to be studied which mechanisms are responsible for the transduction of the environmental cues into physiological modifications.

Funding and support: Fondap-Ideal 15150003 and ANID-Millennium Science Initiative Program-Center ICM-ANID ICN2021_002; Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantártico (BASE), PROPOLAR-Programa Polar Português, Project ANTARCTIC-D-LIGHT. FCT grants PTDC/BIAANM/3484/2014; UIDB/04326/2020.

1503

Vertical profiling radar observations of precipitation dynamics at King Sejong station, Antarctic Peninsula.

Dr. Claudio Durán-Alarcón¹, Dr. Irina Gorodetskaya¹, Dr. Sang-Jong Park², Dr. Vincent Favier³

¹Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Matosinhos, Portugal. ²Korea Polar Research Institute (KOPRI), Incheon, Korea, Republic of. ³CNRS, IRD, Grenoble INP Institute of Engineering, Université Grenoble Alpes, Grenoble, France

Abstract

This work presents the first findings from precipitation observations using a 24-GHz vertical profiling micro rain radar (MRR-PRO), deployed at the King Sejong Station (KSJ) in February 2023, located in the northern Antarctic Peninsula (AP). This dataset encompasses the first full-year of ongoing radar precipitation observations in this region. The MRR-PRO enables the acquisition of high-temporal (1 min) and high-vertical (50 m) resolution profiles of Doppler moments, including radar reflectivity (Ze) and vertical velocity (W), with a vertical extent of 6 km, covering the entire precipitation zone in the troposphere. This surpasses previous radar precipitation observations in Antarctica, such as those at Dumont d'Urville, Mario Zucchelli, Princess Elizabeth, and Vernadsky stations. Results show that less than 50% of the precipitation comes from altitudes above 2 km, altitude where Ze decreases towards the surface, indicative of the sublimation region. W exhibits a consistent pattern of around 1 m/s between 4 km and 500 m, with notable variations near the surface attributed to rainfall. Temporal variability analysis indicates that occurrence of intense precipitation events near the surface (Ze > percentile 90) exhibit significant fluctuations throughout the year, with no distinct seasonal patterns observed. This study conducts an in-depth analysis of phase transitions of precipitation, with a specific focus on the variability of the melting layer altitude, and a disaggregation of radar profiles based on thermodynamic phase, virga occurrence, seasons, and various meteorological conditions, in combination with in-situ meteorological data and radiosondes (February 2023 and 2024). The results will be compared with analogous datasets from other Antarctic stations and the Alps during winter. These preliminary findings offer valuable insights into the intricate dynamics and patterns of precipitation in the AP, underscoring the significance of detailed analysis of vertical profiling radar observations for comprehensive meteorological studies in the Antarctic region.

1505

Carbon sequestration in Antarctic Peninsula fjords under the influence of glacial retreat, Potter Cove as a model ecosystem

Diego Román Giménez^1,2, María Piotto^1,2, Luciana Torre^1,2, Camila Neder^1,2, Luciana Ferrero^1,2, Patrick Monien³, Ricardo Sahade^1,2

¹Instituto de Diversidad y Ecología Animal (IDEA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina. ³Alfred Wegener Institute (AWI), Bremerhaven, Germany

Abstract

The impact of climate change on the Antarctic cryosphere has led to the emergence of new available areas for primary production and benthic colonization, potentially resulting in increased atmospheric Carbon uptake and therefore, negative feedback to Climate Change. It has been suggested that Antarctic fjords could represent Blue Carbon areas, however there is scarce information about their potential for C sequestration. We analyzed total organic and inorganic Carbon (TOC and TIC) content and estimated its residence time along 36 cores extracted from Potter Cove (25 de Mayo Island, South Shetland Islands, Antarctica). Two cores were selected for ²¹⁰Pb isotope-based sediment dating technique for aging C horizons. GLMMs were used to detect changes in TIC and TOC along sediment depths and locations. We found TOC differed among areas, but it did not significantly vary with core length, suggesting very low remineralization over time. Instead, TIC values varied differently through core length and areas. Our findings suggest that Potter Cove soft bottom areas present a long-term Carbon burial efficiency. Despite Carbon accumulation is lower than the typical blue carbon ecosystems, it showed mean values of 9.36 +- 0.92 g m^-2 year^-1 with C stock 993 g^-2 accumulated over 100 years which is higher to other Antarctic areas in which this have been analyzed. Our results point out the importance of Antarctic fjords as C repositories with a high sequestration efficiency over long time periods, potentially exceeding centuries. Fjords can also host extensive macroalgal assemblages in hard bottoms with an extended value in C fixation that together with rich and abundant epibenthic faunal assemblages in soft bottoms, which fix and stabilize sediments, increasing C storage and immobilization, highlights the crucial role of Antarctic fjords as a Nature’s Contribution to People especially under the ongoing process of Climate Change.

1506

Likely repercussions of climate change on the unknown biodiversity of the Southern Ocean: The case of the gastropod Neobuccinum E. A. Smith, 1879

Phd Angie Diaz^1,2, Rosvita Gonzalez², Phd Pablo Guerrero^1,2

¹Universidad de Concepcion, Concepcion, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile

Abstract

The projected transformations in the Southern Ocean due to global warming are expected to impact its ecosystems, leading to changes in species distribution patterns. Particularly, benthic species with specific traits such as stenothermy, longevity, and slow generational turnover are likely to be more affected. Moreover, the increasing recognition of cryptic species in the Southern Ocean has prompted a re-evaluation of established biogeography, highlighting the need to better understand and describe the biodiversity of these vulnerable areas. Neobuccinum eatoni, a monotypic circum-Antarctic snail species extending into the subantarctic province (Kerguelen Archipelago), displays a wide bathymetric distribution (from 4 to ~2000 m). It is notable for its extensive distribution, particularly considering its direct intracapsular development. A phylogenetic approach was employed to investigate the evolutionary relationships among Antarctic and subantarctic populations of N. eatoni, assessing the influence of vicariance and dispersal processes on its biogeography, as well as modelling its potential future distribution under two climate change scenarios (IPCC RCP4.5 and RCP8.5). Distinct lineages were identified, including one isolated in Kerguelen and two divergent clades found in sympatry in the South Shetland Islands. The evolutionary scenario suggests the persistence of ancient lineages over time, with divergence processes likely followed by secondary contact, resulting in a complex of cryptic species. Future distribution projections under RCP8.5 indicate significant long-term changes, with a notable increase in proximity to the continent, while the Kerguelen Archipelago (type locality), Heard Island, and McDonald Islands are expected to face a 99% loss. These findings underscore the intricate evolutionary history of Neobuccinum and emphasize the risk of undiscovered biodiversity loss. Understanding these dynamics allows for anticipating future biogeographic shifts in the Southern Ocean and calls for conservation efforts targeting endemic species.

1507

Aerosol characterization at the Unión Glacier, Antarctica: Particulate matter concentration and size distribution

Prof. Dr. FRANCISCO CERECEDA¹, Dr. Maria F. Ruggeri¹, Dr. Gonzalo Barcaza¹, Ing. Agr. Ximena Fadic¹, Oceanogr. Nicolás Zelaya¹, Prof. Dr. Hans Moosmüller²

¹Centre for Environmental Tecnologies, Universidad Técnica Federico Santa María, Valparaíso, Chile. ²Division of Atmospheric Sciences, Desert Research Institute, Reno, USA

Abstract

Aerosol particles are major, short-lived climate forcers, because of their interaction with solar radiation, and the Antarctic is the most sensitive region in the world respect to radiative forcing and climatic effects. Due to Antarctic amplification, characterizing Antarctic aerosols is of great importance in the battle against climate change.

Here, we present preliminary results from an Antarctic field campaign conducted during the Austral summer of 2024 (INACH ECA60). For first time, concentrations of PM₁₀, PM_4.0, PM_2.5, PM_1.0, and size distribution of particulate matter between 0.25-35 um of aerodynamic diameter, were measured on the Union Glacier (UG), only 1000 km from the south pole, using an aerosol laser spectrometer (DUSTDECODER 11-D, DURAG GROUP-GRIMM, Germany). The instrument operated a flow rate of 2 L min⁻¹, and collected data every 6 s. The monitoring station was installed 1 km upwind from base camp and was powered with a 256 Wh autonomous battery (EcoFlow- River 2, EFR600, China) equipped with a photovoltaic panel to avoid possible contamination from combustion-based energy sources.

For one week of sampling, we measured average particulate matter (PM) mass concentrations of 0.075 and 0.183 ug/m³ for PM₁ and PM₁₀, respectively with concentration ranges of 0.004 to 0.60 ug/m³ for PM₁ and 0.006 to 19.5 ug/m³ for PM10. Moreover, only particles up to a size of 3.24 um in aerodynamic diameter were observed with the highest particle numbers at 0.25 um, accounting for 65% of the total number of particles measured. 99% of the measured particles were in the range of 0.25 to 1.42 um..

The average PM concentrations found in this study were lower than those found in other parts of the Antarctic including the Southern Ocean and the Antarctic coast, highlighting the low presence of aerosols and clean atmosphere of UG.

Acknowledgments: INACH RT_34-21, ACT-210021, FOVI-230167, Fondecyt-1221526

1512

PLANS FOR DEPLOYMENT OF IONOSPHERIC HF DOPPLER SOUNDING PROVIDING 3-D PARAMETERS OF ATMOSPHERIC GRAVITY WAVES AT THEIR HOTSPOT NEAR ANTARCTIC PENINSULA

Jaroslav Urbar¹, Jaroslav Chum¹, Dalia Obrazova¹, Jan Lastovicka¹, Andriy Zalizovski^2,3,4

¹IAP CAS, Prague, Czech Republic. ²Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Kharkiv, Ukraine. ³Space Research Centre of the Polish Academy of Sciences, Warsaw, Poland. ⁴National Antarctic Scientific Center of Ukraine, Kyiv, Ukraine

Abstract

Atmospheric gravity waves (GWs) represent an important wave mode that propagates at periods longer than about 5 min. GW enable the interaction, „coupling“ of the lower and upper atmosphere, influencing the dynamics of the region in which they dissipate. That causes perturbations in the ionosphere, which influence propagation of electromagnetic waves.

Multipoint Czech Continuous Doppler Sounding System (CDSS) allows monitoring the GW occurrence with individual reflection points corresponding to different sounding paths (transmitter-receiver pairs), its multifrequency option enables height-resolution as different frequencies are reflected simultaneously from different heights between ~150 and ~260 km, depending on ionospheric conditions which are monitored by the ionosonde.

Taking advantage of ionosonde operated at Akademik Vernadsky station, the actual reflections heights can be obtained. The Czech Republic is rebuilding Antarctic base at Nelson island (CZ*ECO Nelson), close to the gravity wave hotspot of the Drake strait, being at suitable distance (180 km) to original Czech Johann Gregor Mendel base for resolving the GW using multipoint CDSS transmitters. For the analysis of GW propagation it would be needed to install third transmitter at e.g. the Esperanza, Bernardo Higgins or nearby base, so we seek further collaboration for placement of device having as low as 5 Watts power requirement.

The HF Doppler ionospheric measurements can along with identification of medium scale wave activity provide also estimation of the level of the related GNSS positioning errors.

CDSS were deployed at several places in Europe and in South Africa, but are in operation also in areas with enhanced variability of low-latitude ionosphere (at crest of equatorial ionization anomaly) in northern Argentina and Taiwan.

1513

Rapid Assessments, Stark Realities: AI-Enhanced Multi-UAV Surveys Reveal Recent Declines in Adélie Penguin Numbers on Ross Island

Annie Schmidt¹, Kunal Shah^2,3, Mac Schwager³, Abram Fleishman⁴, Grant Ballard¹

¹Point Blue Conservation Science, Petaluma, USA. ²Figure AI, Sunnyvale, USA. ³Stanford University, Palo Alto, USA. ⁴Conservation Metrics, Santa Cruz, USA

Abstract

As the pace of global change accelerates, there is an increasing need for rapid assessment of related impacts on populations, even for those which are believed to be healthy. In this context, UAVs offer several advantages over traditional aerial surveys, including lower cost, ease of deployment, reduced risk to participants, and reduced disturbance to wildlife. In this study, we: 1) tested the feasibility of using a multi-UAV system to conduct regular surveys of large penguin colonies in Antarctica, 2) developed an automated workflow to increase the speed, efficiency, and precision of processing data from UAV surveys. We designed a multi-UAV path-planning method optimized to make the best use of limited flight time. We demonstrated the algorithm’s capabilities by using a team of drones to conduct multiple photographic surveys at three Adélie penguin colonies on Ross Island, Antarctica. The largest colony, which contains ~250,000 breeding pairs and spans over two kilometers, can now be surveyed at high resolution in under two hours. In contrast, previous human-piloted single-drone surveys of the same colony required nearly three days to complete. We constructed a workflow that generates a mosaicked image of the penguin colony, uses a trained convolutional neural network model to predict the number of penguins in the image, and applies post-prediction statistical corrections to generate a breeding population estimate. We provide estimates of the number of breeding pairs at all three colonies from 2019-2023, highlighting an alarming two-year decrease at Cape Crozier, a large colony that had been increasing steadily over the past 20 years.

1514

Toward an Antarctic phycopathology: description of wild pathosystems associated to Antarctic macroalgae from South Shetland islands.

Dr Pedro Murúa¹, Dr Liliana Muñoz¹, Mr Bastian Añasco¹, Mr Carlos Stange¹, Dr Yacine Badis², Dr Pieter van West³, Dr Claire Gachon⁴

¹Universidad Austral de Chile, Puerto Montt, Chile. ²UMR 8227, Station Biologique, Roscoff, France. ³University of Aberdeen, Aberdeen, United Kingdom. ⁴Muséum National d'Histoire Naturelle, Paris, France

Abstract

Antarctic biodiversity is one of the most unknown in the world, a situation that increases with less charismatic organisms, such as algal pathogens. Antarctic phycopathology is virtually non-existent in this region, both in biodiversity and in the availability of laboratory pathosystems. In this work we report new records of a plethora of pathogens that infect Antarctic macroalgae, from cryptic phaeoviruses and rotting bacteria to abundant green algal endophytes and protists, records obtained from a combination between direct diagnosis, sub-cultivation and DNA barcoding from specimens collected over three campaigns between 2022-2024. Interestingly, some of the most diseased organisms were the most common in the intertidal. In Urospora penicilliformis and Ulothrix spp. we found the first record of marine oomycete, as well as the first green algal chytrid for the region. Also infecting filamentous green algae, we found a bacterial pathogen that colonizes Urospora by overgrowing colonially, degrading the host's cell wall and forcing the host's cytoplasm out of the cell for digestion. The prevalence of these pathogens was highly variably temporally, with a significant increase towards the end of summer and where present in almost all areas sampled in King George and Nelson Islands, and with no significant variation among different populations' bathymetric distributions. In further studies we are comparing how similar are these members of the Antarctic macroalgal pathobiome with similar species from subantartic environments.

1516

Black Carbon Deposition, Snow Albedo, and Radiative Forcing in the Antarctic: Insights from Two Consecutive Field Campaigns in Different Locations

Prof. Dr. FRANCISCO CERECEDA¹, Dr. Maria F. Ruggeri¹, Dr. Gonzalo Barcaza¹, Chemist Franco Sandoval¹, Ing. Agr. Ximena Fadic¹, Prof. Dr. Hans Moosmüller²

¹Centre for Environmental Tecchnologies, Universidad Tecnica Federico Santa María, Valparaíso, Chile. ²Division of Atmospheric Sciences, Desert Research Institute, Reno, USA

Abstract

Black carbon (BC) deposition onto snow plays a crucial role in the Earth's energy balance and climate. Our study focuses on understanding the spatial and temporal distribution of BC in Antarctic snowpacks and its impact on surface albedo and radiative forcing (RF). We present findings from two consecutive Antarctica field campaigns conducted during the Austral summers of 2023 and 2024 (INACH ECA59 and ECA60).

Snow samples were collected and analyzed as described in Cereceda-Balic et al. The SNICAR model was employed to simulate snow albedo for observed BC concentrations, and to evaluate BC-induced RF.

During ECA59, snow samples were collected from multiple locations across the eastern sector of the Antarctic Peninsula (AP), including research bases, remote regions, and icebergs. BC concentrations ranged from 2.4 to 1157 ng g^-1, resulting in albedo reductions of up to 20% and instantaneous RF of up to 38 W m^-2. The recorded BC concentrations were higher than previously observed concentrations in the AP.

In ECA60, the focus shifted to Unión Glacier (UG), only 1000 km from the south pole. Snow samples collected near the research camp and away from it showed BC concentrations ranging from below our detection limit (0.5 ng g^-1 for clean snow) to 30.6 ng g^-1. This led to albedo reductions of up to 2.3% and instantaneous RF of up to 8.6 W m^-2. These findings agree with previous data from UG.

The observed variability in BC concentrations between the two locations and campaigns highlights the large spatial heterogeneity of Antarctic BC deposition and its effects on surface albedo and RF. Overall, our results underline the significant influence of BC deposition on snow albedo and RF in Antarctica, where monitoring and research are essential to better understand the implications of BC for regional climate change.

Acknowledgments: INACH RT_34-21, ACT-210021, FOVI-230167, Fondecyt1221526

1517

INTERNATIONAL COOPERATION ON THE ANTARCTIC CONTINENT: AN APPROXIMATION OF CRIMINAL LEGISLATION AGAINST SEXUAL HARASSMENT FOR THE PROTECTION OF SCIENTIFIC FREEDOM AT WORK.

Luis Felipe da Silva Mathias, Dr Claudio Macedo de Souza

UFSC, Florianopolis, Brazil

Abstract

The research aims to seek a methodology to approximate the criminal legislation of the signatory countries of the Antarctic Treaty System (ATS) to confront sexual harassment on the Antarctic continent, based on the principle of freedom of scientific research by the researchers in the workplace. This study is based on cases of violence and sexual harassment that have already occurred in Antarctica and is supported by the scope of Convention 190 of the ILO - International Labor Organization, which applies to all people in the world of work, regardless of their contractual status, including those who exercise the authority, functions and responsibilities of an employer. As a result, the problem gravitates around the need to face real cases of sexual harassment in the polar environment. As a result, the research project asks the following question: "How can the commitment to international cooperation for scientific research provided for in the ATS can incorporate the legal duty to protect researchers on the Antarctic continent from sexual harassment at work?" A solution to the problem is thus offered with the following preliminary answer: "A methodology aimed at harmonizing the criminal normativity that aims to harmonize the criminal legislation of the countries that are signatories to the ATS, based on the principle of the freedom of scientific research of the researcher in the work environment, offers the conditions for dealing with sexual harassment on the Antarctic continent. It is therefore assumed that the concept of harassment on the Antarctic continent will have to be broadened, given that violence at work can take various forms and cause physical, psychological, sexual and economic damage, as well as offending scientific freedom.

1518

Antarctica takes over the city: engaging the local community through an urban science festival

Dr Julia Saravia^1,2,3,4, Dr Valentina Bernal^3,4, Dr Leyla Cárdenas^5,2, Nadia Politis³, Constanza Barrientos^3,6, Marisol Barria⁷

Abstract

Science festivals provide an ideal space for scientists and the public to interact, especially when they are held outside institutions. Moreover, science festivals in public spaces help to engage broader audiences while giving the public the opportunity to have a flexible and personal experience. Although there are numerous science festivals in Chile, they are broad in scope, are oriented to school audiences and/or take place in regions that already have a certain Antarctic identity. Despite Chile’s long history in Antarctic science, of which a high proportion is conducted by scientists in Valdivia, the Valdivian public is not familiar with the research being done in their city. We therefore organized "Antártica en tu ciudad" (Antarctica in your city), the first Antarctic urban science festival aimed to bring awareness about Antarctic science, understanding of their processes as told by their protagonists, and thus arouse interest on Antarctic ecosystems in the local community. The activity involved the collaboration of several institutions, local authorities, and researchers at different stages of their careers. It consisted of an open-air fair on November 30, 2023, in the city center of Valdivia. The festival included 4 stands, 11 scientific posters, 1 interactive booth with Antarctic flora and fauna on display, 1 space for children and 1 mural with additional information. Well-known biological models served to attract attention (e.g., penguins, seals) and spark interest in lesser-known species (e.g., Notothenioid fish, Littorinid snails, algae). The audience ranged from early childhood to senior citizens. The spatial layout favored the permanence and circulation of attendees. A survey was conducted to measure impact, although the results are inconclusive. Possible alternatives are discussed, as well as strategies and recommendations for future events and locations. Funding: ANID Fondecyt Postdoctorado 3230234, ANID–Iniciativa Científica Milenio – ICN2021_002, FONDAP IDEAL 15150003.

1520

Comparing endolithic and edaphic microbial community diversities from Livingston Island and King George Island (South Shetland)

PhD Student Ignacio Gutiérrez-Cortés¹, MSc Student Karolay Montecinos^1,2, MSc Student Sharon Cablat^1,3, PhD Jean-Baptiste Ramond¹

¹Extreme Ecosystem Microbiomics & Ecogenomics Lab., Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. ²Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago, Chile. ³Université de Pau et des pays de l’Adour, Pau, France

Abstract

The Antarctic continent is polyextreme environment which limits the presence of higher organisms such as plants. As a result, Antarctic microorganisms and microbial communities are the main drivers of biogeochemical cycling. Antarctic microbial communities have developed various strategies to survive and even thrive in such harsh environment. One such strategy is the colonization of refuge niches such as the cracks, pores and/or fissures of rocks. These communities are known as endolithic communities where the colonized rocks provide notably with physical stability, thermal buffering, and protection against UV irradiation. Using 16S rRNA gene metabarcoding, we compared the microbial community diversities from rocks and soils originating from the same sites of two South Shetland Islands, i.e., Livingston Island and King George Island, to better understand the assembly of Antarctic edaphic and endolithic communities. These islands are 75 km distant. Our results suggest that globally endolithic communities are rather similar while the edaphic ones appear rather island dependent relatives to the physicochemiscal propeties. We conclude that local soil physicochemistries and climate are important factors to understand the structuring of Antarctic microbial communities. Furthermore, microorganisms to colonize rocks are subjected to extensive selection independently of the rock type.

1522

Disparate dispersal behavior of fledgling Adélie penguins from three colonies

Dr. Grant Ballard¹, Dr. Annie Schmidt¹, Dr. Amelie Lescroel¹, Dr. Sean Burcher², Dr. Katie Dugger^3,4, Dr. Megan Cimino^5,6

¹Point Blue Conservation Science, Petaluma, USA. ²Cellular Tracking Technologies, Rio Grande, USA. ³USGS, Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, USA. ⁴Dept. Fisheries Wildlife and Conservation Sciences, Oregon State University, Corvallis, USA. ⁵University of California Santa Cruz, Santa Cruz, USA. ⁶NOAA SWFSC Ecosystem Science Division, Santa Cruz, USA

Abstract

Several studies have implicated post-fledging survival as an important driver of Adélie penguin population dynamics, but juvenile seabirds are particularly difficult to study as they do not return to breeding colonies for several years post-fledging. In late Jan/Feb 2023, we deployed newly developed, transmitting GPS-TDR tags on 54 fledgling Adélie penguins on Ross Island at Cape Crozier (~250K breeding pairs) and Cape Royds (2.4K breeding pairs) in the Ross Sea. In Feb 2024, we deployed an additional 20 tags at Humble Island (~500 breeding pairs) in the West Antarctic Peninsula. These colonies have had different population trajectories over the past 50 years, with declines at Humble, relative stability at Royds, and increases at Cape Crozier. We have shown previously that, during the breeding season, prey is depleted near Crozier, but not at Royds. Over the first 30 days, fledglings from Crozier moved rapidly in a northeasterly direction and into pelagic waters, covering an average of 61 km per day. Fledglings from Royds stayed near the Victoria Land coast and moved only 25 km per day. Similarly, fledglings from Humble Island traveled an average of 30 km per day and stayed near land. Fledglings performed fewer and shallower foraging dives compared to adults over the same period but started to approximate adult dive behavior by the end of the first 30 days at sea. Tag attrition was higher for Royds and Humble Island fledglings over the first 30 days (70 - 75% lost) compared to Crozier fledglings (40% lost), suggesting higher early mortality rates of fledglings from the smaller colonies. While other explanations are certainly feasible, we hypothesize that a lack of competition for food near small colonies may lead to a trap whereby fledglings don’t disperse quickly enough to avoid depredation by leopard and fur seals.

1524

PROTECTION OF WHALES IN THE LIGHT OF THE ANTARCTIC TREATY SYSTEM

Catalina Gatica Fernández^1,2, Montserrat Peña Marambio^1,2

¹University of Chile, Santiago, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile

Abstract

This study analyzes whaling protection in the Antarctic Treaty System (ATS) context. Although the International Convention for the Regulation of Whaling (ICRW) was drafted before the ATS, there is a connection with that regime because many commercially exploited whale species inhabit territories under its protection. Although the ICRW seeks to regulate, but not prohibit, whaling and does not consider the environment in its regulations due to the context of its creation, it has evolved towards a conservation approach and the implementation of the moratorium on commercial whaling.

However, countries such as Japan, whose whaling activity is a subject of international legal disputes, have opposed these developments and even in 2018, Japan denounced the Convention. Nonetheless, certain provisions of the ATS, such as the environmental principles of the Protocol, could be applied to whaling activities.

In this context, although the Environmental Protocol expressly excludes from its scope whaling or fishing activities, it is currently feasible to recognize certain countries that, through their domestic legislation, have extended the general procedures of the ATS to such activities.

Even though there is a generalized opposition to whaling, it is feasible to assert that this attitude could change in the future, especially given the emergence of new subsistence needs and associated problems. In such a case, there would be no logical reason to exempt the whaling activities developed in areas covered by the Antarctic Treaty's Environmental Protocol from the environmental protection standards enshrined in it.

1525

Spatio-temporal comparison of gentoo penguin foods webs on Macquarie Island

Miss Georgia Mergard¹, Dr Julie McInnes¹, Professor Mary-Anne Lea¹, Dr Bruce Deagle², Professor Ben Raymond³

¹Institute for Marine and Antarctic Studies, Hobart, Australia. ²CSIRO, Hobart, Australia. ³Australian Antarctic Division, Hobart, Australia

Abstract

By depicting trophic interactions within food web networks, we can evaluate ecosystem structure, identify potential regime shifts, and infer an ecosystem's capacity to adapt to environmental stressors. Examining the diets of marine predators can serve as a means of evaluating the impact of environmental change on marine systems and potentially predicting future ecosystem states. DNA metabarcoding can provide high-resolution dietary data from land-based marine predators non-invasively. Ecological network analysis provides a quantitative framework for describing food web properties and deriving metrics that reflect structural and compositional shifts, feeding patterns, and ecosystem resilience. Using dietary data from marine predators on Macquarie Island, we aim to develop a molecular ecosystem monitoring framework that employs ecological network analysis to detect change. By constructing networks across a spatio-temporal gradient and deriving metrics that describe the structural and compositional shifts, we can establish a framework for evaluating changes in a species' diet, as well as the structural resilience of its food web. Despite the gentoo penguin (Pygoscelis papua) global population being stable, their breeding success on sub-Antarctic Macquarie Island is decreasing. This suggests that regionally specific change may be responsible for this population decline. As such, we use gentoo penguins as a case study, utilising ecological network analysis to assess regionally specific changes in their food web, specifically across breeding sites and seasons. Using dietary data derived from scat samples across six breeding seasons, we undertake an inter and intra annual comparison of network metrics, identify changes in network structure and determine whether structural changes correlate with fluctuations in gentoo penguin breeding success. We then use these findings to inform future studies by providing recommendations for the assessment of network metrics in investigating regionally specific changes in food web structure, facilitating the development of an ecosystem monitoring tool for sub-Antarctic Macquarie Island.

1526

Exploration of sub-glacial geology in the Antarctic continent from gravity regression analysis

Renata Constantino^1,2, Kirsty Tinto¹, Leonardo Uieda², Carla Braitenberg³

¹Lamont-Doherty Earth Observatory, Columbia University, New York, USA. ²Institute of Astronomy, Geophysics and Atmospheric Sciences, University of São Paulo, São Paulo, Brazil. ³University of Trieste, Department of Mathematics and Geosciences, Trieste, Italy

Abstract

The current understanding of sub-glacial geology in Antarctica is derived from numerous individual studies. One way to analyze it is by using information of the gravity field, which can help reveal and define the depth and geometry of density heterogeneities in the crust and upper mantle. Although there has been a significant increase in aerogeophysical investigation of the continent, satellite data still gives the opportunity to reveal geologic information from gravity signals on a continent-wide scale with uniform precision and resolution.

Regression analysis between satellite gravity and topography has been evaluated on a global scale but not focused on the Antarctic continent. The analysis has proved to efficiently isolate the signal of density inhomogeneities and also to guide the understanding the isostatic compensation mechanism. Here we run a regression analysis over the entire Antarctic continent using the Bouguer anomaly estimated from satellite gravity data and equivalent topography (i.e. the height or depth that the crust will assume in the absence of ice or water) assuming an Airy compensation mechanism. Interpretation of the regression coefficients can reveal density heterogeneities and/or a crust that is isostatically under/over compensated.

Preliminary results indicate that parts of southern Transantarctic Mountains, Marie Byrd land and the Peninsula are closely compensated according to the Airy model. Over East Antarctica, three areas are subject to investigation for possible unknown sedimentary basins. The results will be compared to a sedimentary basin likelihood map from Random Forest classification.

1528

Measuring Antarctic Sea Ice decadal variability using the Differing Data Distribution Index.

Iuri Gorenstein¹, Ilana Wainer¹, Mauricio Mata², Marcos Tonelli¹, Fernanda Marcello¹, Marina Noro dos Santos¹

¹Universidade de São Paulo, SÃO PAULO, Brazil. ²Universidade Federal do Rio Grande, Rio Grande, Brazil

Abstract

In the last decade, Antarctica’s Sea Ice Extent (SIE) has attained its maximum (2014) and minimum (2023) values, raising questions regarding the evolution of SIE variability. This work uses a probability density function and examines the mean and standard deviation of SIE distributions as a function of seasonality. A methodology previously used in Gorenstein et al., (2022), the Diferring Data Distribution Index (DDDI) is an alternative way to compare data distributions and analyze climate data. Unlike the traditional trend calculation, the DDDI methodology reveals the rate of change between two data distributions not necessarily connected in time. Examining the SIE data from the Southern Ocean and its seas, the distributions from 1983-1996, 1996-2009, and 2010-2023 are compared and their DDDIs are calculated and discussed.

1531

HSP70 gene expression and protein levels in two notothenioid fish under immunostimulation and thermal variation

Dr Julia Saravia^1,2,3, Dr Kurt Paschke^4,2,3, Dr Juan Pablo Pontigo⁵, Mg Daniela Nualart^1,6,3,7, Mg Carina Chipon⁸, Dr Jorge M Navarro^1,2, Dr CH Christina Cheng⁹, Dr Luis Vargas-Chacoff^1,2,3

¹Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ²Centro FONDAP de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Punta Arenas, Chile. ³BASE Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago, Chile. ⁴Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile. ⁵Laboratorio Institucional, Facultad de Ciencias de la Naturaleza, Universidad San Sebastián, Puerto Montt, Chile. ⁶Centro FONDAP de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ⁷Escuela de Graduados, Programa de Doctorado en Ciencias de la Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile. ⁸Laboratorio de Farmacología y Fisiopatología Pulmonar, Instituto de Farmacología y Morfofisiología, Universidad Austral de Chile, Valdivia, Chile. ⁹Department of Evolution, Ecology, and Behavior, University of Illinois, Urbana-Champaign, USA

Abstract

Heat shock proteins (HSPs) constitute a large and highly-conserved group of proteins. They have been studied extensively because of their critical role in avoiding protein damage from heat stress, but also for several less-mentioned functions, such as during the immune response. While the inducible Hsp70 members are greatly upregulated under thermal stress in a variety of organisms, it has been argued that this particular response would be absent for several if not all Antarctic notothenioid fish species. However, recent work shows that this may not be the case for the intertidal notothenioid fish Harpagifer antarcticus and its close relative H. bispinis. Adult fish of H. bispinis and H. antarcticus were collected from Punta Arenas (Chile) and Bahia Fildes (Antarctica) respectively and distributed as follows: injected with PBS (control), LPS (2.5 mg/kg) or Poly I:C (2mg/kg) and then submitted to 2, 5 and 8°C. After 7 days, samples of gills, liver and spleen were taken to evaluate the differential gene expression of HSP70 by real time PCR, and protein levels by Western Blot. Expression of the HSP70 gene was tissue specific in both species, being higher at higher temperatures in liver and gills, and higher at lower temperatures in spleen. We found no difference between immunostimulants, but temperature and the interaction between temperature and immunostimulants had a significant effect on the expression of HSP70. Preliminary analysis showed differences in protein levels among treatments, but these deviated from the pattern expected from gene expression. The results are discussed in the context of physiological stress associated with thermal variation and pathogen translocation due to climate change.

Funding: ANID Fondecyt Postdoctorado 3230234, Fondecyt de Iniciación 11230401, ANID–Iniciativa Científica Milenio – ICN2021_002, FONDAP IDEAL 15150003.

1534

Ecological parameters of bivalves from the La Meseta Formation (Seymour Island, Antarctica): response to environmental changes in the Eocene

Tamiris Morilla¹, Fernanda Quaglio²

¹University Federal of Triângulo Mineiro, Uberaba, Brazil. ²University Federal of São Paulo, São Paulo, Brazil

Abstract

Global cooling associated to glaciation records in the Antarctic occurred in the beginning of the Oligocene, which represents the last Greenhouse-Icehouse change on Earth. The La Meseta Formation comprises a record previously to this shift and is composed of a succession of sandstones and fine sediments deposited in alluvial, deltaic and marine off-shore environments during conditions of incise valley filling. The unit preserves rich macroinvertebrates, especially mollusc bivalves occurring in bioclast lenses and beds along the unit. These fossils were analysed according to ecological parameters related to temperature, substrate, bathymetry and guilds. By using modern representatives for definition these parameters, we used correspondence and squad analyses that resulted in high significance for the total values in two principal axes: temperature (95%) and geographic distribution (91,66%), however these are scattered when related to Telms. Bathymetry (62,1%) shows high correspondence between 250 meters deep and Telms 2,3 and 5, whereas guilds (61.8%) indicate suspensive mobile infaunal and facultatively mobile infaunal are associated to Telms 2,3,5 and 6. Regarding substrate (65,1%), finer sediments are more associated with bivalves in higher strata. Our results indicate that bathymetry, substrate and guilds are associated with upper Telms, and that temperature is not stratigraphically significative. This suggest that, at least for the La Meseta bivalves, change in the compositional fauna may reflect local environmental changes related to deepening towards the top of the unit, instead of global scale changes.

Keywords: Temperature; Substrate; Bathymetry; Facies control; Paleogene; Climate Changes.

1535

High spatio-temporal reconstruction of snow cover variability in Chilean southern Patagonia

Dr Francisco Aguirre^1,2, Dr Deniz Bozkurt^3,4, Dr Jorge Carrasco², Dr Tobias Sauter⁵, Dr Christoph Schneider⁵, Ms. Christie Vera⁶, Dr Ricardo Jaña⁷, Dr Gino Casassa²

¹School for Field Studies, Puerto Natales, Chile. ²Centro de Investigación Gaia Antártica (CIGA), Universidad de Magallanes, Punta Arenas, Chile. ³Center for Climate and Resilience Research (CR)2, Santiago, Chile. ⁴Departamento de Meteorología, Universidad de Valparaíso, Valparaiso, Chile. ⁵Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany. ⁶Universidad de Magallanes, Punta Arenas, Chile. ⁷Scientific Department, Chilean Antarctic Institute, Punta Arenas, Chile

Abstract

Climate change particularly affects cold regions, such as southern Patagonia, which has shown a significant decrease in snow cover in recent decades. This work implements a novel methodology for studying snow cover variability at a high spatial-temporal resolution that integrates three main processes applied to MODIS satellite (MOD09) products: (1) increase the spatial resolution data to 250 m using a spectral fusion technique; (2) a novel snow-cloud discrimination based on three different index (Normalized Difference Snow Index (NDSI); Melt-Area Detection Index (MADI); and Spectral Mixture Analysis (SMA)); (3) a daily spatio-temporal reconstruction of snow extent and its albedo signature using an endmember extraction and spectral mixture analyses. Snow reconstructions were performed in 6 main basins of the Chilean southern Patagonia, within low elevation (<1500 m a.s.l.) and mid-latitude locations: (1) Rio las Chinas basin (50.7171 °S, 72.7745 °W); (2) Río Ventisquero basin (51.4089 °S, 72.7943 °W); (3) Cerro Mocho basin (51.4916 °S, 72.6029 °W); (4) Sierra Dorotea basin (51.6024 °S, 72.4453 °W); (5) Río Penitente basin (52.2802 °S, 72.1723 °W); and (6) Brunswick basin (53.3204 °S, 71.2289 °W). These basins are important in terms of water supply to the population, livestock activities, and future development of facilities for winter sports. The snow cover reconstruction results for 2000-2023 show a significant decrease being more pronounced in the last period (2010-2020). Moreover, a significant drought has affected the area during the last 2 decades, which has contributed to snow cover decrease. However, more than changes in precipitation, the significant rise in winter temperatures, accompanied by melting pulses during the winter season, are detected and suggested as the main drivers of these changes. In future climate change scenarios, these trend are predicted to increase.

1536

Women of the ice: An oral history of female Antarctic scientists

Linda Hunt

University of Tasmania, Hobart, Australia

Abstract

Antarctic is a gendered space. Historic tropes of heroic white men battling the elements continue to feature in contemporary news coverage of the continent. Recent reviews of diversity, equity, and inclusion in national Antarctic programs in Australia and the United States have highlighted the marginalisation of women in this unique setting. The ‘Women of the Ice’ project seeks to shift the focus of Antarctic stories away from tales of adventure and exploration to stories that amplify the role of women in Antarctic science. By retelling the modern history of Antarctica through the experiences and achievements of women, this project can develop new understandings of the continent. This presentation discusses the need for a media project highlighting the contribution of women to the continent in both historical and contemporary times. It will also discuss the benefits offered by oral history as a method of research, and how this rich resource can be used in subsequent creative representations to reach a wider, general audience. By disrupting existing narratives, this project can elevate the voices of female scientists and their contribution to critical research about a place that has a key role in the fate of the planet.

1539

Zonal symmetry of the SAM and its impacts on sea levelin the South Atlantic Ocean

Dr Venisse Schossler^1,2, Dr Francisco E Aquino^1,2, MSC Rafael C Silva^1,2, Dr Jefferson C Simões^1,2, Dr Pedro T Valente^1,2, Bsc Pedro HR Lira^1,2

¹Centro Polar e Climático - Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²INCT da Criosfera, Porto Alegre, Brazil

Abstract

Global warming has modified the ocean-atmosphere interaction, causing sea level (SL) rise regionally. Due to the lack of long-term South Atlantic data, we study the relationships between the recent thirty years of satellite sea level anomalies (SLA-Copernicus) data (1993 - 2022) and the variability of atmospheric circulation over the South Atlantic. As the leading mode in the interannual variability of the low-level atmosphere in the Southern Hemisphere is the Southern Annular Mode (SAM), we observe these changes from of its positive trend in recent decades. We found positive SL tendency to 1993 – 2022, negative from 1993–2008 and positive from 2009–2022 (p-value < 0.01). So, we observe winds (10m u and v), mean sea level pressure (SLP) (ERA 5) and wind stress curl (FNMOC) in these three periods. There was an intensification of meridional winds towards the equator on the African coast and poleward on the South American coast. In the central-western region of the ocean the influence is lower, being negatively correlated with SLP. To the south of this region and in coastal areas the correlation is positive. The zonal winds are negative correlated with the SLP over South Atlantic, except for the equatorial region, were is positive correlated. Between the first and second period, this correlations get stronger. The SLP climatology represent the positive SAM index result (1.4) for the time series. The mean SAM index (Marshall 2003) is higher in the second period, reinforcing the South Atlantic anticyclone. The decadal spin up of the subtropical gyre associated to increase in SL, cited in the literature, results from the increased surface wind stress curl associated with an enhanced SAM and subtropical high.

1542

Climate change and extreme events associated with tropical-polar teleconnections in southeastern South America

Dr. Francisco Eliseu Aquino^1,2, Dr. Venisse Schossler¹, MSc Rafael César Silva^1,2, MSc RonaldoTorma Bernardo¹, Dr. Gabriel Selbach Hofmann^1,2, Dr. Pedro Teixeira Valente¹, Dr. Carolina Barnes Gramcianinov^3,1,2, PhD Jefferson Cardia Simões¹, MSc Isaias Ulman Thoen¹, UG Guilherme de Aquino Curia¹

¹Centro Polar e Climático, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500 - Building 43136 room 210 91501-970, Porto Alegre, Brazil. ²Graduate Program in Geography, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500 - Building 43113 room 208 91501-970, Porto Alegre, Brazil. ³Institute for Coastal Systems Analysis and Modeling, Helmholtz-Zentrum Hereon, Max-Planck, Geesthacht, Germany

Abstract

Global environmental changes motivate us to explore the extreme events and climate connections between Antarctica and the South America (SA). Other reasons for this are the migration of the subtropical atmospheric circulation towards the poles, caused by the expansion of the Hadley cell and the positive Southern Annular Mode (SAM) trend. We performed observations of meridional and zonal winds (m s^-1) and geopotential height (850, 500 and 200 hPa) and total rainfall (mm d^-1) from ERA5-ECMWF over the South Atlantic and SA between 1990 and 2023. It is notable the expansion of the Hadley cell and the increase of the zonal pressure gradient over SA in the past decade, not coincidentally, the period that contains the warmest years. Lastly, it is also necessary to connect that we identified that south of Brazil, a subtropical region, is sensible to explosive cyclones genesis (e.g. September/October 2016, June/July 2020) during years of intensified tropic-pole interactions and negative SAM. By investigating the precipitated water moisture source, through its isotopic composition, and the atmospheric characteristics of SA and Antarctica, we recognized hazards due to associated intense precipitation, two historic floods in Taquari river valley in 2023, windstorms and hail. When there is the presence of a South American Low Level Jet (SALLJ reaching 30 m s^-1) the humidity of the Amazon contributes markedly (δ18O reaching +1.05‰) in the intensification of these events. The coupling of the SALLJ to the jet streams (subtropical/polar jet), influenced by a zonal wave pattern 3 or greater, associated with the passage of a cold front, intensifies cyclogenesis, severe thunderstorms and other natural hazards. On other occasions, in the intense heat exchange between the Amazon and the Weddell/Bellingshausen seas, we observed extreme events associated with polar fronts/cyclones with a marked record of δ18O (-8.00‰) of Antarctic origin.

1549

Impacts of polar brine pond and active layer processes on supra-permafrost geochemical alteration and mineral development in xeric basins of Wright Valley (McMurdo Dry Valleys, Antarctica)

Dr. Zachary Murguía Burton¹, Dr. Janice Bishop², Dr. Peter Englert³, Dr. Christian Koeberl⁴, Dr. Everett Gibson⁵

¹Bates College, Lewiston, USA. ²SETI Institute, Mountain View, USA. ³University of Hawai‘i at Mānoa, Honolulu, USA. ⁴University of Vienna, Vienna, Austria. ⁵NASA Johnson Space Center, Houston, USA

Abstract

Less than 1% of Antarctica is free of perennial ice and snow cover. Nonetheless, at several thousand km² in size, Victoria Land’s McMurdo Dry Valleys (MDV) comprise the continent’s largest ice-free area, providing an exceptional opportunity to investigate water-limited geochemical processes in one of the coldest, driest environments on Earth. What’s more, although the Antarctic cryosphere has been the focus of extensive research effort, the study of permafrost-associated aqueous and geochemical processes in ice-free regions has received comparatively little attention. Accordingly, we focus our attention on a water-limited but hydrologically dynamic endorheic basin—hosting an ephemeral brine pond, shallow groundwater system, and permafrost within the upper meter of regolith—in the South Fork of MDV’s Wright Valley. We present results of spectroscopic, mineralogical, and geochemical analysis of a 24 cm-thick, supra-permafrost regolith profile to characterize chemical alteration products associated with the various aqueous processes intermittently active in this basin. Within this sediment profile, we document distinct mineralogical horizons: ~0–4-cm depths are characterized by salts; ~4–7-cm depths comprise a clayey layer of poorly crystalline aluminosilicates and iron oxides/hydroxides (plus notably elevated elemental concentrations); ~8–10-cm depths (and to a lesser extent, ~10–15-cm depths) are characterized by calcium sulfates; and ~15–24-cm depths (to top-permafrost) are generally characterized by salts. We suggest these stratified aqueous mineralogical assemblages preserve record of water cycling driven by numerous intermittent hydration (and evaporation) processes, including sublimation of surface meltwater, subsurface pooling of brine pond water at a silty aquiclude (the clayey interval), and active layer freeze-thaw cycling of permafrost meltwater, along with potential pooling of meltwater atop a permafrost aquiclude. Active layer and supra-permafrost aqueous processes may similarly impact geochemical cycling and mineralogical development of regolith in other ice-free areas of Antarctica, as well as permafrost regions globally.

1550

What are the ethical implications of opportunistic epidemiological surveillance in the tourism sector?

Keltoum Boumedjane

Abstract

With the threat of the Highly Pathogenic Avian Influenza (HPAI) virus having recently reached the sub-Antarctic and Antarctic regions, a program of opportunistic surveillance has been set up within the Southern Ocean luxury cruise network. If the methods used for the epidemiological surveillance and the reporting of suspected cases can be described as a citizen science -despite their modest effectiveness, aren't we here facing a form of cooperation that is renewing the ethical debate between science and tourism? Does this new form of collaboration present an opportunity or a risk of greenwashing?

In France, scientists' unease is palpable with the recent controversy over the cruise ship Commandant Charcot that is hosting opportunistic scientific campaigns. Cruise ship communication strategies emphasize the role of science ambassadors, while some scientists denounce the instrumentalization of research to improve the image of an industry that is still highly polluting, especially in a fragile environment.

As the cruise perimeter is wider than the conventional perimeter to which scientists have access in research bases, this initiative increases the wildlife monitoring area in remote and difficult-to-access locations. The tourist activity completes a geographical space that is fragmented in terms of research, while feeding the HPAI databases.

However, the cases reported are not always credible, and raise ethical questions about the reliability of sources and the recognition of all the parties involved in the information transmission chain. Indeed, a cormorant courtship was interpreted as a visible sign of neurological disorders characteristic of HPAI, revealing a lack of training in detecting the clinical signs of the disease. Furthermore, cases of suspected HPAI on a private island in the Falklands/Malvinas were not shared with the farmers living on the island, raising the question of how local populations are taken into consideration in the cross-border institutional dynamics of HPAI surveillance.

1552

Traveling in times of Highly Pathogenic Avian Influenza: a new form of biosecurity and disease surveillance commitment?

Keltoum Boumedjane

Abstract

From on-board disinfection stations -with the inevitable passage to footbaths, to boot-washing stations set up temporarily when landing, tourists and tourist operators are caught up in a network of mobile biosafety frontiers. While biosecurity protocols have been put in place on cruise ships to prevent the introduction of invasive alien species into the sub-Antarctic and Antarctic regions, the Highly Pathogenic Avian Influenza (HPAI) threat has given a new dimension to the rituals of sanitization.

The biosafety imaginary is no longer relegated to the dimension of the invisible, of introduced species too small to be perceived. The HPAI biosecurity can be seen in the new control exercised over gestures, with a series of prohibitions such as not sitting down or not putting anything on the ground during shore visits. In addition to complying with biosecurity protocols before and after a visit, the perimeter of responsibility seems to extend throughout the visit, with ordinary gestures now outlawed, resulting in a shift from a passive to an active form of health risk paradigm.

The active dimension of control is also to be found in the collective effort to monitor infectious diseases, by detecting and reporting suspicious mortalities or abnormal behavior in animals potentially affected by the HPAI virus. While this new type of cooperation in the tourism sector can be interpreted as a form of participatory science for a sustainable future, the results must be put into perspective. Between a lack of training, a failure to report within a useful timeframe or a lack of information relay, the quality of epidemiological surveillance from the tourism sector remains to be perfected in order to improve the HPAI monitoring database. Although suboptimal, this form of opportunistic surveillance can potentially extend detection zones, since the perimeter of cruise ships is wider than the perimeter of scientists.

1554

Drivers and characteristics of white capping during atmospheric river events affecting the Antarctic Peninsula

Alizée De Groodt^1,2, Paulo Avilez-Valente^1,2, Isabel Iglesias¹, Irina Gorodetskaya¹

¹Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Porto, Portugal. ²Faculty of Engineering, University of Porto, Porto, Portugal

Abstract

Atmospheric rivers (ARs) are long corridors of high amounts of moisture known for their important role in transporting heat and water vapour poleward. They often form and intensify over the Pacific Ocean and are linked with extreme weather events. As they move towards the Antarctic Peninsula (AP), ARs can cause various impacts, such as anomalous precipitation, surface melt, sea ice disintegration and large waves. Although ARs are associated with strong winds, few studies have focused on their impact on the dynamics of the upper ocean layer. Our study focuses specifically on the generation of large and steep waves that release significant amount of sea spray droplets into the atmosphere as the waves break, a process known as whitecapping. These droplets contain sea salt aerosols (SSA) that can significantly influence cloud and precipitation formation along the AR path. The wave model WAVEWATCH III was used to investigate the impact of the waves generated during an AR, which caused warmer air temperatures, rainfall, and increased wind speeds in the northern AP. The model is forced with hourly sea surface wind from ERA5, and hourly sea surface currents and sea ice cover from CMEMS. Multigrid simulations were performed with a large, coarse-resolution grid covering the entire Southern Ocean (30ºS to 80ºS, 0.5º 0.5º), and a finer grid (4’ 4’ resolution) over the AP and surrounding ocean (50ºS–72ºS, 90ºW–30ºW). Two sensitivity studies were analysed: one with climatological average sea ice cover; the other with anomalously low sea ice cover observed in February 2023. The most affected regions, in terms of wave steepness and whitecapping coverage and thickness, are identified. Our study provides insights on the drivers and characteristics of whitecapping, which is an important factor in the release of SSA and thus can influence cloud dynamics, ultimately impacting the warming of Antarctica.

1557

The Colors of the Astrolabe:Picturing the Spectral Blues of Glaciers during the French Exploration of Antarctica, 1837-1840

Ph.D. Candidate Delanie Linden

Massachusetts Institute of Technology, Cambridge, USA

Abstract

This lecture explores the international competition for polar exploration in the 1830s and 1840s that gave rise to a proliferation of brilliant botanical and glacier watercolors in the nineteenth century. On the eve of September 7, 1837,Captain Jules Dumont d’Urville and his team of artists, geologists, chemists, and military officials, among others, set sail out of the port of Toulon for the southern shores of South America, Antarctica, and islands of the Pacific. Throughout their three-year voyage, artists produced hundreds of paintings depicting colorfully exotic plants and sublime blue landscapes.

Yet, capturing the landscape of Antarctica—for the first time—posed a tremendous problem for French painters: the translucent forms of glacial landscapes challenged conventions of painting shadows and the illusion of three-dimensional form on canvas. In some cases, the visual observation of shadows was difficult; on other occasions, the penumbral hues were so brilliant, so blue, purple, and black, that artists were confounded by its variety. Moreover, the glacial topography was exceptionally bright, bewildering artists: How does one render the volume of hills and valleys, edges and smooth slopes, water and ice, when colorants of the same type: blue and blue, white and white, collide?

My presentation will focus on several paintings held in the Natural History Museum in Paris (Muséum nationale d’histoire naturelle, MNHN). Looking at artist journals as well as scientific notebooks produced during the sail of the Astrolabe in Antarctica, I will discuss how new inventions of the colorant blue in Paris helped painters to depict the spectral blues of glacial Antarctica.

1560

Impact of Heat Waves on thermal tolerance and metabolic physiology of Antarctic amphipods

Dr Kurt Paschke^1,2,3, Dr Luis Vargas-Chacoff^4,2,3, Daniela Nualart^5,2,3,4, Dr Stephen McCormick⁶, Dr Pedro Guerreiro^7,8, Dr Paulina Gebauer⁹, Dr Julia Saravia^2,3,4, Gabriel Lezana¹, Dr Jorge Navarro^4,2, Dr Carlos Rosas¹⁰

¹Institute of Aquaculture, Universidad Austral de Chile, Puerto Montt, Chile. ²FONDAP Research Center: Dynamics of High Latitude Marine Ecosystems (IDEAL), Punta Arenas, Chile. ³Millennium Institute Biodiversity of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile. ⁴Institute of Marine and Limnological Sciences, Universidad Austral de Chile, Valdivia, Chile. ⁵PhD Program in Aquaculture Sciences, Universidad Austral de Chile, Puerto Montt, Chile. ⁶Department of Biology, University of Massachusetts, Amherst, USA. ⁷Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal. ⁸PROPOLAR, Portuguese Polar Program, Universidade do Algarve, Faro, Portugal. ⁹Centro i~mar, Universidad de Los Lagos, Puerto Montt, Chile. ¹⁰Multidisciplinary Teaching and Research Unit UMDI-Sisal, Faculty of Sciences, Universidad Nacional Autónoma de México, Sisal, Mexico

Abstract

The projected temperature increase due to global change will not be gradual. Heat waves (HW) are increasingly frequent events that cause drastic changes in a few days. Antarctic intertidal and/or shallow subtidal organisms, such as the amphipods Paraceradocus miersi, Gondogeneia antarctica and Cheirimedon femoratus will be exposed more frequently to these HW. This study aims to evaluate these species' thermal tolerance and resilience against HW of different intensities. The animals were captured from the lower intertidal on King George Island, Antarctica; conditioned at 2,5,8 and 11°C (+3°C/d); kept for 5 days at each temperature; (sampling 1=“heat wave”) and then returned to 2°C (control) (-3°C/d)(sampling 2=“resilience”). After Routine oxygen consumption (QO2) measurements, individuals were frozen in liquid N2 for subsequent biochemical analysis. Hypoxia tolerance (Pcrit) was evaluated in another group of animals to estimate the individual oxygen supply capacity, alpha.

After 5 days under HW conditions, the animals increased their QO2 proportionally to the wave temperature up to 8°C, decreasing at 11°C, indicating a stressful condition (corroborated by 100% mortality at 11°C in G.antarctica). After the HW, the animals of the 5°C and especially 8°C treatments significantly reduced their QO2. Preliminary analysis showed that this reduction in energy supply capacity after HW, interpreted as the costs for Resilience, allowed us to estimate a temperature threshold. Moreover, these temperature values were correlated with the oxygen supply capacity, alpha.

The results show the high sensitivity of these animals to heat waves and low resilience, making them vulnerable to these global change events.

Acknowledgements: INACH; Funding: FONDECYT-1221623; FONDAP IDEAL 15150003; ANID–Iniciativa Científica Milenio – ICN2021_002

1562

Geobiology of Antarctic Subglacial Environments: An historical perspective

Professor Emeritus John Priscu¹, Professor Emeritus Chuck Kennicutt²

¹Montana State University, Bozeman, USA. ²Texas A&M, College Station, USA

Abstract

Antarctica is the highest, driest and coldest continent on earth. It holds 90% of our world’s ice and 70% of its freshwater. If the ice melts, sea level will rise about 60 m and inundate more than 12 million km² of land. The early explorers referred to it as a place devoid of life. The idea that the Antarctic ice sheet was lifeless persisted for more than 80 years, when the first explorers stepped foot on the continent. Recent research has now shown that huge river basins and some of our planet’s largest lakes exist beneath more than 4 km of Antarctic ice providing new information on the stability of the West Antarctic Ice Sheet and biodiversity on the continent. Collectively, these data reveal that subglacial aquatic ecosystems in Antarctica form the largest wetland on our planet. Given the isolated, dark and frigid conditions presented by this environment, we do not find cattails and red winged blackbirds, common to surface wetlands; instead, the environment is completely microbial. These organisms mine the energy in rocks and in relict marine sediments to obtain energy to support their existence, while at the same time mobilizing nutrients that fuel life in the coastal regions of Antarctica. Our presentation will present the history of subglacial exploration from the groundwork set by early SCAR working groups SALEGOS and SALE to the present day.

1563

Advancing Radio Astronomy: Site Characterization and Telescope Development in Antarctica for Epoch of Reionization Studies

Dr. Julian Rodriguez-Ferreira

Universidad Industrial de Santander, Bucaramanga, Colombia

Abstract

Antarctica offers ideal conditions for space observation due to its dry, cold, and stable atmosphere. This work is led by the Universidad Industrial de Santander, built on previous collaborations between Colombian universities such as, Universidad de Antioquia, and Universidad ECCI, as well as international collaborations with the Astro-Engineering and Microwave Laboratory of the Catholic University of the Santísima Concepción (LAIM-UCSC) and the Astronomy department at University of Concepción, expanding to international projects in continental and Antarctic territories as a part of the Colombian Antarctic Program (PAC), aims to establish a permanent Colombian base in Antarctica with an astronomical radio observatory, enabling the reception of radio signals from the Universe in a location with exceptional characteristics. Our research, spanning two Antarctic summer campaigns (2023 and 2024) at Capitan General Bernardo O'Higgins Riquelme Antarctic Station, involves measuring radio frequency interference (RFI), assessing soil electrical resistance, and installing a weather station for continuous monitoring in 2024. The project is a response to the Scientific Committee on Antarctic Research's (SCAR) prioritization of observing space and the Universe in Antarctica, acknowledging the continent's potential for contributing to understanding the early universe. We present here the 2023 and 2024 results to validate our low-frequency radio telescope for studying the reionization epoch of the Universe. This initiative has the main objective of field-testing a prototype radio telescope and characterizing the electromagnetic climate for future observatories. This research results include the quantified RFI noise occupancy in the radio spectrum, validation, and measurement system under Antarctic conditions and informed decisions on candidate sites for future observatories. The Antarctic expeditions, conducted in the 2023 and 2024 southern summers, lasted 2 months each, focusing on-site setup, scientific measurements, and equipment validation and finalized with the RFI measurement and first light of the low-frequency radio telescope in Antarctic conditions.

1568

Underwater with a hand lens: ecological sciences and environmental ethics to value freshwater biodiversity in sub-Antarctic and Antarctic ecosystems

Tamara Contador^1,2,3,4, Javier Rendoll-Cárcamo^1,2,3,4, Melisa Gañan^1,2,3,4,5, Brenda Riquelme^1,2, Katherine Chavez^1,2,3, Gabriel Muñoz^1,2,3, Jaime Ojeda Villarroel^1,4, James Kennedy^1,6, Peter Convey^7,2,1,8, Ricardo Rozzi^1,4,9

¹Cape Horn International Center (CHIC), Puerto Williams, Chile. ²Millennium Institute of Antarctic and sub-Antarctic Ecosystem (BASE), Santiago, Chile. ³Millennium Nucleus of Austral Invasive Salmonids, Concepción, Chile. ⁴Universidad de Magallanes, Punta Arenas, Chile. ⁵FEHM-Lab (Freshwater Ecology, Hydrology and Management), Departamento de Biología Evolutiva, Ecología i Ciencias Ambientales, Facultad de Biología, Universidad de Barcelona, Barcelona, Spain. ⁶Department of Biological Sciences, University of North Texas, Denton, USA. ⁷British Antarctic Survey (BAS), Cambridge, United Kingdom. ⁸Department of Zoology, University of Johannesburg, Johannesburg, South Africa. ⁹Department of Philosophy and Religion Studies, University of North Texas, Denton, USA

Abstract

Despite their impressive diversity and ecosystem relevance, insects are undervalued and rarely considered in conservation efforts, except for those that are medically or economically important. In terms of funding and effort, insect conservation research lags far behind vertebrate research, hampering the development of methodologies to better understand their conservation needs. This taxonomic bias has a severe limitation in that it only gives moral consideration to our closest evolutionary relatives, excluding the vast majority of other life forms on our planet. In this regard, the Field Environmental Philosophy (FEP) methodology (Cape Horn Center), provides a platform for the development of interdisciplinary approaches to contribute to biocultural conservation, combining ecological research and environmental ethics. We integrated ecological research, education, and environmental ethics over the last fifteen years through the FEP to promote and foster freshwater insect awareness, conservation, and valuing in the Magellanic sub-Antarctic ecoregion of southern Chile and in the maritime Antarctic, working particularly with insects widely distributed in sub-Antarctic streams and with the winged antarctic midge Parochlus steinenii (Diptera: Chironomidae), representing antarctic insects. Central to our approach is the presentation of robust long-term data elucidating the phenological patterns of these species, alongside the philosophical and ethical praxis derived from our work. This integration of empirical research and reflective practice provides a solid foundation for understanding the complex interactions between these insects and their environments, highlighting their intrinsic value and underscoring the urgency of their conservation. Through this work, we aim to catalyze a shift in conservation paradigms, advocating for a more inclusive recognition of biodiversity that encompasses the myriad forms of life on our planet. By instilling scientific inquiry within a multidisciplinary educational framework from the outset, our goal is to challenge and expand current conservation strategies to ensure a more equitable and ethical consideration of insect species worldwide.

1572

Has the International Polar Year learned it's lesson?

Ms Sophie Weeks^1,2, Mr Ramcharan Vijayaraghavan³, Ms Marta Espirito⁴

¹Scott Polar Research Institute, Cambridge, United Kingdom. ²Polar Educators International, Cambridge, United Kingdom. ³Polar Educators International, Chennai, India. ⁴Polar Educators International, Lisboa, Portugal

Abstract

In the run up to the 4th International Polar Year (IPY2007-08), all research proposals submitted to the International Polar Office (IPO) for endorsement were required to include opportunities for education and outreach. Some even placed learning and community engagement at the heart of their project.

Members of the IPO Education and Outreach Committee (EOC) not only established this precedent but also co-ordinated a programme of activities led by educators, scientists and members of the public that generated awareness of and enthusiasm for polar science beyond academia. This programme is described in several IPY papers 2009-2011 and revisited in a special education edition of Polar Record in 2019. It was heralded as ‘one of the largest global investments in science outreach to date’. So it is no surprise that grassroots networks of practice like the Association of Polar Early Career Scientists (APECS) and Polar Educators International (PEI) emerged, developed public engagement strategies and still continue to be essential outcomes of the 4th IPY.

This paper considers the research impact of the IPY through polar education , specifically tthe role of the PEI network and the wider benefit to the economy, society, culture, public services, health, the environment and quality of life, beyond academia. It presents how PEI supports educators preparing future generations for climate adaptation and resilience; connect researchers and educators, and grow Antarctic knowledge and understanding, embedding a better understanding of earth's systems. It asks why polar education, a significant, measurable example of research impact, is mostly voluntary, goes largely unrewarded and is regarded as an add-on by both the polar research and education community. Finally, through the lens of polar education and impact, it asks why should polar education have a role in the 5th IPY? And how and who will determine what it should be?

1574

Glacioeustacy versus plate tectonics: testing old paradigms about the South America-Antarctic-Oceania connection during the Cretaceous in the light of old and new palaeontological findings

Dr. Marcelo Leppe¹, Dr. Cristine Trevisan², Lic. Juan Pablo Pino³, Dr. Joseline Manfroi⁴, Dr. Leandro Martínez⁵, Dr. Alexander Vargas^3,6, MSc. Viviana Lobos⁷, Lic. Héctor Mansilla², Dr. Gerson Fauth⁸, Dr. Agustín Martinelli⁹

¹Nucleo Milenio EVOTEM, Punta Arenas, Chile. ²INACH, Punta Arenas, Chile. ³Universidad de Chile, Santiago, Chile. ⁴CIAHN Atacama, Atacama, Chile. ⁵Museo Histórico Regional, Neuquén, Argentina. ⁶Nucleo Milenio EVOTEM, Santiago, Chile. ⁷Consejo de Monumentos Nacionales, Santiago, Chile. ⁸UNISINOS, Sao Leopoldo, Brazil. ⁹Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina

Abstract

The Campanian-Maastrichtian interval (83.6 to 66.0 Mya) represents one of the most important questions regarding the biogeography and evolution of the Austral-Antarctic biota, but especially regarding the driving forces behind the emergence and disappearance of species, many of Gondwanan origin, that are in the fossil record or as survivors in the continents inheriting South Gondwana. This work discusses the importance of cooling events in the Campanian-Maastrichtian, in the context of the transition from a hyper-greenhouse world to a period of global climate cooling, in which significant negative carbon isotope anomalies (δ13C) occurred. The Late Campanian (LCE) and Campanian-Maastrichtian Boundary (CMBE) events mark the beginning of this trend and also mark the beginning of changes in the finicretaceous assemblages in Patagonia and Antarctica. Various factors, such as temperature changes, ocean circulation and the opening of the gateway, have been suggested as sources of these alterations, but no precise mechanism has yet been clearly delineated. Even less is known about their effect on climate and biota at high latitudes. Using the published record of plant and animal taxa in southern South America, the Antarctic Peninsula and Oceania for this interval, with significant new findings, we correlate known glacioeustatic events that could explain, beyond classical tectonic solutions, the complex patterns of species distribution, especially at localities in Chilean and Argentinean Patagonia and the Seymour/Marambio, James Ross, Vega and Nelson Islands in Antarctica, and analyse possible causes in the recently calibrated eruptive cycles of the Deccan Traps.

Acknowledgments:

FONDECYT Postdoctoral Grant N°3230319

Millenium Nucleus EVOTEM NCN2023_025

1575

The IceCube Upgrade at the South Pole

Michael DuVernois

University of Wisconsin, Madison, USA

Abstract

The IceCube Observatory at the South Pole has detected high energy neutrinos of cosmic origin, including point sources and unresolved Galactic and extragalactic source populations. The extensions to IceCube include the fully funded and under construction low energy, finely segmented extension of the detector (IceCube Upgrade) and a future high energy, high statistics next generation telescope using a mix of optical and radio detectors (IceCube-Gen2). We will focus on the science impacts along with the hardware and logistics of the Upgrade construction from the past season and the next two Antarctic working seasons (2024-25 & 2025-26).

1576

Distribution of terrestrial land surface covers in the northern Antarctic Peninsula region using reflectance spectroscopy

Dr. Thomas Schmid¹, Ms. Claudia Giménez-Poblador¹, Dr. Robert Milewski², Prof. Dr. Sabine Chabrillat^2,3, Dr. Stéphane Guillaso², Dr. Marta Pelayo¹, Dr. Tanya O'Neill⁴, Dr. Magaly Koch⁵, Dr. Jerónimo López⁶

¹CIEMAT Centro de Investigaciones Energéticas Medio Ambientales y Tecnológicas, Madrid, Spain. ²GFZ German Research Center for Geosciences, Potsdam, Germany. ³Leibniz University Hannover, Hannover, Germany. ⁴Waikato University, Hamilton, New Zealand. ⁵Boston University, Boston, USA. ⁶Universidad Autónoma de Madrid, Madrid, Spain

Abstract

Ice-free areas within the northern Antarctic Peninsula region lie, mainly near the coastlines, with a variety of terrestrial landforms formed by marine, glacial, periglacial and paraglacial landforms and processes. These areas are potential hotspots of biodiversity as there is a concentration of flora and fauna. Novel remote sensing data and improved techniques are useful for characterizing and monitoring these often inaccessible areas. The objective of this work is to determine the distribution of different terrestrial land surface covers of ice-free areas within the northern Antarctic Peninsula region using reflectance spectroscopy. This included: 1) updating the Northern Antarctic Peninsula Spectral Library (NAPSPEC), 2) extracting and interpreting spectral information from high spectral resolution satellite imagery and 3) obtaining a set of image derived endmembers for surface cover classifications of selected test sites. Detailed field observations and sample collection were obtained in different ice-free areas of the South Shetland Islands and the Danco Coast in the northwestern Antarctic Peninsula during four austral summers (2016-2017, 2017-2018, 2021-2022 and 2023-2024). Field spectroradiometry was carried out for selected field plots using an ASD FieldSpec3 full spectral range instrument (350 to 2500 nm). Hyperspectral data from the German Environmental Mapping and Analysis Program (EnMAP) was obtained for selected sites on Byers Peninsula (Livingston Island) and Cierva Point on the Danco Coast. Reference spectra from 38 plots were compiled to the existing NAPSPEC library. These included surface covers such as patterned ground, stone fields, rock outcrops, detrital deposits, moraine deposits, ice and snow cover and vegetation covers (mainly mosses and lichens). Image-derived endmembers were obtained from the EnMAP imagery for known test sites and were well identified and labelled using the reference spectra of NAPSPEC. These results are key in choosing a set of endmembers for the supervised classifier such as random forest.

1584

Clinical health status and biomonitoring of pollutants in adults living in Antarctica: a novel study

PhD Sandra Cortes¹, PhD Karla Pozo², PhD Petra Růžičková², PhD Petra Přibylová²

¹Pontificia Universidad Católica de Chile, Santiago, Chile. ²RECETOX. Masaryk University, Brno, Czech Republic

Abstract

The presence of persistent and non-persistent pollutants, some of them called endocrine disruptors (ED) are strongly associated with chronic diseases in human populations. The occurrence of environmental exposures to these pollutants has been well documented in several Chilean studies, on human exposure (PCB in milk, Arsenic in urine, Lead in the blood). The lack of baseline concentrations is one of the most important limitations for their use as biomarkers of exposure and for studying its changes according to specific early damage biomarkers. The main problem is to define whether exposure to low levels of a mix of contaminants using small samples is related to possible mechanisms responsible for ED-induced chronic diseases. A human biomonitoring pilot study in people exposed to a "pristine environment", as happens in the Chilean Antarctic, is an excellent strategy for establishing a baseline of ED and for understanding whether changes in the exposure biomarkers are related to health status. Furthermore, this initial examination of people exposed to Antarctica can contribute to a better understanding of the human metabolic status as a model of a “pristine environment”.

We propose the utility of follow-up studies carried out on adult people who must temporarily reside in Chilean Antarctica, which will allow an understanding of actual exposure levels of ED, define specific exposure sceneries, and identify possible early damage markers. A baseline measurement of the health status will be carried out on adult volunteers living in Antarctica. A panel of exposure and early damage markers will be evaluated from blood and urine samples. Exposure to contaminants will be evaluated in RECETOX.

The novel knowledge will be fundamental for programming new studies in the Antarctic and evaluating metabolic changes using new approaches, such as Exposomics, Metabolomics, and Proteomics tools.

1585

Outcomes of the SCAR Highly Pathogenicity Avian Influenza Monitoring Project

Dr Meagan Dewar

Federation University Australia, Berwick, Australia

Abstract

In preparation for the arrival of highly pathogenicity avian influenza (HPAI) into Antarctica, the Antarctic wildlife health network established the HPAI Monitoring project to monitor the movement and spread of the virus throughout the sub-Antarctic and Antarctic regions. Reports of unusual behaviour and mortality observed in species during the Austral season from National Programs, IAATO and local governments in the sub-Antarctic and Antarctica.

In October 2023, HPAI was first detected at Bird Island, in the sub-Antarctic region, and rapidly spread throughout South Georgia. Throughout the season, some signs of unusual behaviour were detected in species throughout the region, but it wasn’t until February that the first confirmed case was detected at Primavera station. This presentation will display the results of the monitoring database, showing the known movement and potential movement of the virus into the Antarctic region and the potential for the database to monitor the incursion and spread of other infectious diseases.

1588

Interaction between the atmosphere and surface on the Antarctic continent in summer period

Dr Irina Repina, Arseniy Artamonov

A.M. Obukhov Institute of Atmospheric Physics RAS, Moscow, Russian Federation

Abstract

In summer, turbulent heat fluxes are the main sources of heat entering the atmosphere for ice- and snow-free areas of Antarctica and, therefore, can contribute to more intense melting of snow and glaciers. Accordingly, ice-free areas of Antarctica can be an important source of energy for the entire region and should be included in regional climate models. Therefore, studying the interannual and spatial variability of energy balance in ice-free regions of Antarctica provides valuable information about how these new conditions may affect land-atmosphere interactions and future Antarctic climate.

The work examines the results of direct measurements of turbulent fluxes at the c Bellingshausen and Novolazarevskaya stations in the summer seasons. The measurement results show that in summer the surface temperature and albedo can change several times in close surface arease. Also, surface contamination of various origins can affect the thermophysical characteristics of the surface. Analysis of the data showed that, despite the general qualitative similarity in the behavior of energy exchange characteristics in different years in the Antarctic Peninsula region, differences are observed related to the local synoptic situation. Flows also depend on wind conditions (wind speed and direction) and precipitation patterns. Standard calculation methods based on the Monin-Obukhov similarity theory can be used to determine the characteristics of energy exchange in the coastal regions of Antarctica, but taking into account the characteristics of the underlying surface and outside extreme stratification conditions. At the same time, as measurements show, in coastal and close to oases areas of Antarctica during the melting period, positive heat fluxes can also form above the glacier, contributing to the formation of convective conditions. With strong daytime heating, the surface of glaciers and snowfields can also be a source of heat entering the atmosphere. The work was supported by the Russian Science Foundation grant 24-17-00155.

1590

Diatom, clay and geochemical records of Pleistocene West Antarctic Ice Sheet instability in the outer Amundsen Sea, last 600,000 years

Professor Reed Scherer¹, Dr. Claus-Dieter Hillenbrand², Mr. Joseph Ruggiero^1,3, Mr. Joseph Mastro^1,4

¹Northern Illinois University, DeKalb, Illinois, USA. ²British Antarctic Survey, Cambridge, United Kingdom. ³Colorado School of Mines, Golden, Colorado, USA. ⁴ERM: Environmental Resources Management, Melville, New York, USA

Abstract

Drilling (IODP Exp. 379) and coring on sediment drifts of the outer Amundsen Sea has provided high quality, continuous Pleistocene records. From these we have produced paleotemperature and clay mineralogical evidence of likely West Antarctic Ice Sheet collapse events and enhanced southward flow of deep waters during most, if not all, interglacials of the last 600,000 years.

A quantitative paleotemperature proxy has been developed based on morphologic variance in the dominant Southern Ocean diatom Fragilariopsis kerguelensis. We have tested and improved on a previously published calibration of the proxy and find that it works well in the Amundsen Sea sector of the Southern Ocean. We find that interglacial temperatures exceeded 2ºC during nearly all interglacials, implying surface warming and enhanced advection of northern waters toward the ice sheet. A comparable record, in higher resolution, was generated from clay mineral assemblages, providing compelling evidence of dramatically reduced delivery of West Antarctic interior sediments to the Southern Ocean and enhanced advection of clays from sub-Antarctic Pacific basins during these interglacials, further suggesting WAIS collapse events.

1592

Extreme warm events and snowfall to rain transition over the Antarctic Peninsula during atmospheric rivers

Irina Gorodetskaya¹, Claudio Durán-Alarcón¹, Xun Zou², Sang-Jong Park³, Penny Rowe⁴, Yosvany Garcia Santos⁵, Anastasiia Chyhareva^6,7, Vincent Favier⁸

¹Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto,, Matosinhos, Portugal. ²Center for Western Weather and Water Extremes (CW3E), Scripps Institution of Oceanography, University of California San Diego, La Jolla, USA. ³Korea Polar Research Institute (KOPRI), Incheon, Korea, Republic of. ⁴NorthWest Research Associates, Seattle, USA. ⁵COPAS-Coastal, Department of Oceanography, University of Concepcion, Concepcion, Chile. ⁶State Institution National Antarctic Scientific Center, Ministry of Education and Science of Ukraine, Kyiv, Ukraine. ⁷Ukrainian Hydrometeorological Institute, State Service of Emergencies of Ukraine and National Academy of Sciences of Ukraine, Kyiv, Ukraine. ⁸Institut des Géosciences de l’Environnement, CNRS/UGA, Saint Martin d’Hères, France

Abstract

Atmospheric rivers (AR) play an important role in the Antarctic surface mass and energy balance and becoming more frequent and intense in the warmer climate. In recent years, several remarkable extreme events associated with intense ARs have impacted the ice sheet, causing major heatwaves, anomalous precipitation and surface melt particularly over the Antarctic Peninsula (AP) (Gonzalez-Herrero et al., 2022; Gorodetskaya et al., 2023). The hot spell that affected the AP in February 2022 showed that an intense AR can induce a strong impact in a short time, including anomalous rainfall amount. Here we focus on this and other AR events reaching the AP coast during 2022-2024 and bringing extreme warm conditions and rain analyzing their characteristics and drivers. We use observations conducted at King Sejong station (King George Island, northern AP) and Vernadsky station (northwestern AP) including thermodynamic structure of the troposphere measured with radiosondes and precipitation profiles from MRR-PRO radar. Preliminary results during a selected AR at the northern AP showed strong temperature inversions in the first 3 km including a melting layer changing its height between 2-km to near the surface and marking a sharp transition from snowfall to rain. High-resolution simulations with the Polar-WRF model, incorporating advanced topography and forced by ERA5 reanalysis, are evaluated using observations and used to study cloud and precipitation microphysical properties, as well as spatial scale of the AR events over the entire AP, with a focus on snowfall to rainfall transition.

Funding: Portuguese Polar Program; FCT; KOPRI; ANR ARCA.

References:

González-Herrero et al. (2022): Climate warming amplified the 2020 record-breaking heatwave in the Antarctic Peninsula. Commun. Earth Environ, https://doi.org/10.1038/s43247-022-00450-5

Gorodetskaya et al. (2023): Record-high Antarctic Peninsula temperatures and surface melt in February 2022: a compound event with an intense atmospheric river. npj Clim Atmos Sci, https://doi.org/10.1038/s41612-023-00529-6

1594

Trophodynamics as a tool for monitoring population and community structure of demersal fishes in the Antarctic Peninsula: challenges for fishery management and conservation

Mr Francisco Santa Cruz, Dr César Cárdenas

Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

The Antarctic toothfish (Dissostichus mawsoni) is the largest notothenioid species in the Southern Ocean, playing a keystone role in the trophic web as a food source for marine mammals and a top predator in deep-sea ecosystems. Most ecological knowledge on this species relies on samples from areas where direct fishing is allowed, whereas in areas closed to fishing, such as the Antarctic Peninsula (AP), there are still key ecological gaps to ensure effective conservation. Here, we review feeding behavior of Antarctic toothfish caught in the AP, from macroscopic morphological and DNA-based studies. Results revealed that the Antarctic toothfish is a generalist predator, with a diet mainly consisted of Macrouridae, Cephalopoda, Anotopteridae, and Channichthyidae. In light of lack direct surveys, the former prey composition is representative of benthopelagic fauna, therefore trophodynamic can be a valuable tool of indirect monitoring of population and community structure of demersal fishes in the AP. The Antarctic toothfish has been consistently managed by the CCAMLR as a key component in the food web dynamics; however, issues including the population status, the effect of environmental change on its complex life cycle, and ecosystem impacts of the fisheries are still to be well understood. Understanding the diet and trophic relationships of Antarctic toothfish is critical for a better comprehension of its role in the benthic-demersal ecosystem, key for ecosystemic fisheries management, and relevant for understanding and predicting the effect of climate change on deep-sea environments. A complete understanding of feeding dynamics and trophic connections is relevant for ecosystem-based stock management in order to develop fishing activities while maintaining ecosystem structure and functioning, especially in deep-sea environments already modified by overexploitation, such as the Antarctic Peninsula, where it is unknown how TOA and the surrounding bentho-demersal community will respond to fishing pressure.

1601

Building Resilience on Antarctic Bases – lessons from 8 stations in the 2024 season

Professor Manuel Correia Guedes¹, Professor Sue Roaf²

¹University of Lisbon - IST, Lisboa, Portugal. ²Heriot-Watt University, Edimburgh, United Kingdom

Abstract

Antarctica bases are facing a number of challenges in maintaining thermally safe environments for their researchers. These include the need to constantly upgrade systems, and reliance on increasing computer base high-tech control systems in bases with poor internet connectivity and distance from technical assistance and parts replacement on the mainland. Add to the isolation of many bases the increased footfall of researchers and guests at bases, more extreme weather events, high turnover of technical staff, rising costs of fuel and its transport, aging mechanical systems and parts replacement problems and the challenges to maintain safe and efficient working conditions on bases can be challenging. This paper aims to try and map the landscape of operational challenges at bases using the experience of visiting eight bases on Antarctica during February by boat and land. The need for confidentiality is paramount but by drawing together the collective case studies together a hierarchy of risks will be presented for discussion. At one end the unimaginable happened and the entire power system failed for nearly five days providing lessons of what steps might be taken in future to lessen the behavioural, technical, physical and cultural impacts of the event. At perhaps the other end the need to reinforce day to day maintenance and testing can significantly improve the overall performance, energy consumption and emissions from bases. A table is presented of described risks for discussion during the forum with a view to stimulating thinking on how best to design and build in features and procedures that can reinforce the resilience of the base occupants to ensure, at very least, their survival during period of extreme weather and energy failures.

1602

Geomorphological characteristics and surface velocities of Hurd rockglacier (Livingston Island, Antarctic Peninsula).

Gonçalo Vieira¹, Gabriel Goyanes¹, Gonçalo Prates^1,2, Joana Baptista¹, Miguel Angel de Pablo³, Mohammad Farzamian^4,1, Carla Mora¹, Paula Matos¹, Marc Oliva⁵, António Correia⁶, Henrique ZIlhão^1,7, Pedro Pina¹, Vasco Miranda⁸

¹Centre of Geographical Studies, Associate Lab TERRA, IGOT, University of Lisbon, Lisbon, Portugal. ²Instituto Superior de Engenharia, Universidade do Algarve, Faro, Portugal. ³Unidad de Geologia, Facultad de Ciencias, Universidad de Alcalá, Alcalá de Henares, Spain. ⁴Instituto Nacional de Investigação Agrária e Veterinária, Oeiras, Portugal. ⁵Department of Geography, Universitat de Barcelona, Barcelona, Spain. ⁶Department of Physics, University of Évora, Évora, Portugal. ⁷Centre of Environmental Chemistry, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal. ⁸CERENE, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal

Abstract

The recent definition of rock glacier velocity as an Essential Climate Variable by the Global Climate Observing System (WMO) emphasises on the significance of monitoring Antarctic rockglaciers. These frozen and deforming masses of rock debris occur in several ice-free peninsulas of the South Shetland Archipelago, yet their geomorphological characteristics, velocities and responses to climate change remain poorly understood. The Hurd rockglacier, situated in Hurd Peninsula on Livingston Island, spans the floor of a small glacial valley, descending from approximately 392 m to sea level at False Bay. This valley, enclosed by steep rock walls with extensive scree slopes, is home to a small, retreating cirque glacier with a notable frontal moraine, giving rise to the rockglacier. The rockglacier itself extends about 630 m in length and 290 m in width, with its surface characterized by pressure ridges and furrows. This presentation synthesizes research conducted on the Hurd rockglacier since 2009. Through a detailed geomorphological map, supported by drone-derived optical orthomosaics and digital surface models, we analyze surface features to gain insights into permafrost dynamics. Vegetation cover has been mapped utilizing a drone-based 10-band multispectral camera, while a thermal infrared camera has allowed surface temperature mapping. The rock glacier's internal structure was examined using electrical resistivity tomography surveys, revealing a frozen core. The kinematics have been analyzed using historical aerial photographs from 1956/1957 and very high-resolution satellite imagery from 2007 and 2019, indicating average deformation rates of 12 to 36 cm/yr. Annual Differential GPS measurements since 2011 have documented deformation rates of approximately 8 to 15 cm/yr. Furthermore, repeat drone surveys have detailed the rock glacier's recent surface dynamics and complemented the D-GPS data. Permafrost boreholes in the Hurd Peninsula offer a basis for discussing the rock glacier's climate sensitivity.

1605

Are microbiota connected between poles? The answer is blowin' in the wind

Antonio Quesada¹, Sergi González-Herrero², David Velázquez¹, Pablo Almela³, Pablo Sanz¹, Francisco Vasallo⁴, Eugenio Rico¹, Samuel Cires¹, Warwick F. Vincent⁵, Ana Justel¹

¹Universidad Autónoma de Madrid, Madrid, Spain. ²WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland. ³University of Minnesota, St Paul, USA. ⁴Agencia Estatal de Meteorología, Rota, Spain. ⁵Université Laval, Québec, Canada

Abstract

The distribution and dispersal of microbial communities in polar regions are mainly shaped by climate dynamics and global-scale processes. Despite extensive research, uncertainties persist regarding the global-scale dispersal of cold-dwelling microorganisms, challenging established hypotheses. Through the study of cyanobacterial communities in polar microbial mats, evidence of shared taxa between the Arctic and Antarctic was found, supporting the possibility that both polar regions are biologically interconnected. Potential mechanisms facilitating this interconnection include, among others, human or animal transport and airborne dispersion. To examine the aerial transport hypothesis, we used high performance computing to conduct a large simulation study including 6.42 million feasible microorganism air transport scenarios. We generated air parcel trajectories with HYSPLIT and incorporated dry and wet deposition models to integrate the physical characteristics of the biological particles. We found that 1.72% of the trajectories reach the opposite pole in less than 180 days and about 15,000 arrived with at least one submicron microorganism. The results demonstrate the potential for airborne particles, including microorganisms, to traverse between the polar regions, influenced by factors such as size, density, and wet deposition processes. These findings suggest that air connections may facilitate microbial dispersal between far distant environments. If some of these microorganisms and propagules retain viability, their long-distance transport would explain the genetic flow from Pole to Pole, and thus the commonalities among microbial communities in the cryosphere.

1611

Composition and abundance of the benthic megafauna in Martel inlet, King George Island, Antarctica using ROV surveys

Mr. André Souza, Dr Linda Waters, Arthur Guth, Monica Petti, Dr Paulo Sumida

Oceanographic Institute - University of São Paulo, São Paulo, Brazil

Abstract

Recent climate change has been associated with numerous adverse effects on benthic Antarctic communities, including population decline, species turnover and local extinctions. Indirect impacts, such as increasing sedimentation rates due to melting ice and more frequent ice scouring have also been observed. To better understand these effects on benthic communities in Martel Inlet, Admiralty Bay (King George Island), it is essential to characterize these communities and their relationship with the environment. We conducted ROV video surveys at ten 10 sites in Martel Inlet, using video frames from depths of 30-40m during the summer of 2022. The sites were categorized based on their proximity to glacier termini: marine terminating glacier (MTG), terrestrial terminating glacier (TTG) and ice-free areas (IFA). Species composition, abundance, and diversity were assessed for all sites. Additionally, Principal Component Analysis (PCA) and Non-Metric Multidimensional Scaling (NMDS) ordinations were conducted on abiotic parameters (such as grain size, organic matter, biodetritic carbon, retraction rates, and total ice area lost) and abundance data, respectively. A total of 5979 individuals were identified using visual ID guides. Among the sites, Krak (MTG) and O’Connor Rock (IFA) exhibited the highest abundance (n=2220 and n=1698), while Punta Ullman (IFA) and Goetel (MTG) showed the highest diversity (27 and 23 morphotypes, respectively). Communities are mostly composed of high numbers of ascidians, ophiuroids, polychaetes, sea urchins and bivalves. Krak was distinguished by the dominance of the coral Malacobelemnon daytonii and the ophiuroid Ophionotus victoriae, whereas O’Connor Rock was dominated by the bivalve Laternula elliptica, and the echinoderms Odontaster validus and Sterechinus neumayeri. Ferraz (IFA) had the highest quantity of Porifera (n=59). PCA analysis of environmental data revealed grain size and organic matter as the primary factors distinguishing stations, while NMDS analysis demonstrated a relationship between community composition and glacier termini at each station.

1614

Valuing field time: developing multiple seafloor visualization methods to compensate for variable Antarctic weather to map benthic megafauna of King George Island

Linda Waters, Arthur Güth, Luis Silva, Monica Petti, Paulo Sumida

Universidade de Sao Paulo, São Paulo, Brazil

Abstract

The harsh weather conditions and high variability over short time spans creates a formidable challenge for data collection in Antarctica, particularly underwater. This has limited, both spatially and temporally, visual Identification of benthic faunal communities on the seafloor in the Martel Inlet, King George Island, for more complete benthic habitat mapping necessary for understanding transitions and ecological community variations. While previous collection attempts have centered on an ROV system, the dependence on ideal weather conditions limiting and the rapid outdating of the onboard camera system has necessitated development of a low-cost and easily implemented alternative. First, the existing Seabotix ROV system was adapted, using the onboard live video (720p) for piloting and built-in depth and temperature sensors, but adding GoPro cameras (4K) to allow refined biota identification. Then, a prototype TowCam system was created, with a QI-1000 inspection camera for live-video steering via a surface boat, the same GoPro cameras for image compatibility (using 2 to compensate for lacking camera tilt control), external lighting, and an attached independent CTD to create the depth, temperature, and salinity profile. The new system cost ~$12,000USD as opposed to ~$71,000USD for an equivalent modern ROV system. The advantages and limitations of each system for identification of benthic megafauna were evaluated in the field at 30 m depths at various points around the perimeter of Martel Inlet from >30 minutes of bottom observations along 16 transects. The ROV system was superior for the factors of surface wind interference, surface ice, camera angle adjustment, data integration, and depth control. The TowCam system, however, performed better for rapid deployment/recovery ability for short field windows, in higher winds, and added superior track georeferencing. The employment of both systems will allow the creation of the first comprehensive habitat map of dominant macrofauna in Martel Inlet.

1621

Evolution and adaptation of terrestrial plant-associated Plantibacter species into remote marine environments

Professor Li Liao

Polar Research Institute of China, Shanghai, China

Abstract

Microbes are thought to be distributed and circulated around the world, but the connection between marine, remote Southern Ocean in particular, and terrestrial microbiomes remains largely unknown. We use Plantibacter, a representative genus associated with plants, as our research model to investigate the global distribution and adaptation of plant-related bacteria in plant-free environments, particularly in the remote Southern Ocean and the deep Atlantic Ocean. The marine isolates and their plant-associated relatives shared over 98% whole-genome average nucleotide identity (ANI), indicating recent divergence and ongoing speciation from plant-related niches to marine environments. Comparative genomics revealed that the marine strains acquired new genes via horizontal gene transfer from non-Plantibacter species and refined existing genes through positive selection to improve adaptation to new habitats. Meanwhile, marine strains retained the ability to interact with plants, such as modifying root system architecture and promoting germination. Furthermore, Plantibacter species were found to be widely distributed in marine environments, revealing an unrecognized phenomenon that plant-associated microbiomes have colonized the ocean, which could serve as a reservoir for plant growth-promoting microbes. Furthermore, the dispersal and successful survival of Plantibacter species in the Southern Ocean indicates that species invasion into Antarctica would likely increase in the future due to climate change, raising concerns about the loss of uniqueness of the Antarctic microbiota.

Acceptance type: Poster

16

Geomorphometric modeling and mapping of Schirmacher Oasis East Antarctica

Mr. Waseem Baba, Prof. Jitendra Pattanaik, Mr Tamta Kumar

Central university of Punjab, India, Bathinda, India

Abstract

Geomorphometric modelling and mapping of Antarctic oases is critical for understanding landscape evolution and glacial dynamics. This article shows the detailed results of geomorphometric modelling and mapping of the Schirmacher Oasis obtained during the 36th Indian Antarctic Expedition in 2016-2017. The study derived digital models and maps of 28 morphometric variables from the digital elevation models viz-a-viz slope, ring curvature, Gaussian curvature, valley depth, wind shelter index, terrain ruggedness, total catchment, profile curvature, relative position, plane curvature, aspect, morphometry feature, LS factor, vertical curvature, mean curvature, minimal curvature, maximal curvature, curvature, difference curvature, vertical excess curvature, horizontal excess curvature, horizontal curvature, accumulation curvature, catchment area, topographic index, Strahler order and stream power index. Of the derived maps for example the minimal and maximum curvature analysis shows two types of elongated linear forms: concave ( valleys) represented by dark blue lines ( k_min < 0) and convex ( ridges) indicated by dark brown lines ( k_max >0). To determine the geological lineaments (folds, faults, etc.) of the oasis, the k_min and k_max maps are the most useful material. The topographic index shows that it reaches high values in regions where catchment area (CA) values are high and at low (slope) G values. The derived maps also indicate that when both CA and G are high stream power index (SI) achieves high values. The importance of these findings resides in the potential use of the geomorphometric maps for a range of scientific investigations, including soil, geochemical and mineralogical studies. The ultimate goal of geomorphometric maps is intended to create a digitized large-scale geomorphometric atlas of Schirmacher Oasis.

Keywords: Schirmacher Oasis, Geomorphometric modelling, Antarctica

18

Tectonic Map of the Antarctic

Dr. German Leitchenkov^1,2, Dr Garrik Grikurov³

Abstract

The 2-nd edition of Tectonic Map of the Antarctic at 1:10 M scale with Expalatiry Notes were published by the International Commission for the Geological Map of the World (CGMW). The map shows the tectonic composition of the Antarctic with major crustal types (continental and oceanic) and their specific structural assemblages (features) in geodynamic context. Design of the legend allows compact visual presentation of both geodynamic and age-related information. Map units are in the first place distinguished by the type of crust they represent, and by formation at plate boundaries or in within-plate settings. Oceanic crust is mapped in accordance with the age of generation identified by magnetic anomalies. Archean complexes are grouped in a separate block of the legend believed to represent a primeval continental plutonic/metamorphic infrastructure (protocrust) lacking clear plate tectonics markers. Proterozoic and Phanerozoic complexes are referred to either unstretched or stretched continental terranes. Unstretched crust comprises accretionary fold belts (orogens), structural products of their reworking, platform covers and intraplate fold systems. Stretched continental crust controls distribution of rift systems and associated sedimentary basins. A greater part of the East Antarctic continental margin belongs to a magma-rich type. Within lengthy zones contiguous to oceanic crust the continental crust is hyperstretched to the extent of unroofing the upper mantle. Generalized view of Antarctic tectonic structures, including their inferred distribution under the ice sheet, is provided in a smaller-scale inset also showing the rates of sea-floor spreading and areas with thickened oceanic crust. Explanatory notes contain description and illustrations of major tectonic elements, as well as references to key data sources used for the compilation.The Map and the Explanatory Notes are distributed on the CGMW website: https://ccgm.org/en/catalogue/.

19

Geology of central Antarctica: study of mineral inclusions from the accretion ice cores at the Vostok Station Borehole

Dr. German Leitchenkov^1,2, Dr. Nikolay Rodionov³, Dr. Anton Antonov³, Dr. Viktoriya Krupskaya⁴, Dr. Ludmila Kryuchkova⁵

¹Institute for Geology and Mineral Resources of the World Ocean, Saint-Petersburg, Russian Federation. ²St.-Petersburg State University, Saint-Petersburg, Russian Federation. ³Russian Geological Institute, Saint-Petersburg, Russian Federation. ⁴nstitute of Geology, Ore Deposits, Petrography, Mineralogy and Geochemistry, Moscow, Russian Federation. ⁵St.-Petersburg State University, St.-Petersburg State University, Russian Federation

Abstract

Additional studies of mineral inclusions from cores of accretion ice provide new information on their initial (intact) morphology and clay mineralogy, the rock clast they contain, the geochronology of detrital zircon and monazite grains in rock clasts, and the provenance of detrital minerals. X-ray microtomography of ice cores containing rock clasts shows that the clasts are covered by a thin film of fine-grained clayey material. Based on this observation we suggest that the rock clasts were captured within the ice grounding zone from the bottom of a shallow bay, located upstream from Vostok Station, and then spent some time in a water pocket with a fine-grained suspension that deposited on the clast surface. Clay minerals, illlite (69%), chlorite (24 %) and kaolinite (7%), were identified in the fine-grained material of the largest mineral inclusion in the accretion ice. The sample studied (as a proxy for lake sediments) is characterized by the absence of mixed-layer (illite/smectite) clay minerals typical of Antarctic coastal regions, which is probably a peculiarity of subglacial weathering in central Antarctica. Detrital zircon U-Pb ages show strong probability peaks at 900, 1000 and 1100 Ma and minor peaks at 760, 800, 900 1300, 1600, 1750 and 2500 Ma, while detrital monazite ages are mainly clustered between 1250 and 1450 Ma with one probability peak at 1100 Ma. The dominant age range for detrital zircons between 900 and 1100 Ma corresponds well with the main phase of the Rayner Orogeny manifested in East Antarctica between Dronning Maud Land and Queen Marie Land although the Gamburtsev Mts with orogenic assemblages of similar ages can be considered as a more probable source region. Detrital monazite grains show a different age distribution compared to detrital zircon and correlate with the early phase of the Rayner Orogeny.

20

Bottom current-controlled sedimentation off Mac.Robertson Land

Dr. German Leitchenkov^1,2, Mrs Julia Guseva³

¹Institute for Geology and Mineral Resources of the World Ocean, Saint-Peterburg, Russian Federation. ²St.-Petersburg State University, Saint-Peterburg, Russian Federation. ³Polar Marine Geosurvey Expedition, Saint-Peterburg, Russian Federation

Abstract

This research is based on about 17 000 km of MCS data collected by several countries over the last 25 years including new 3000 km data collected by the Russian Antarctic Expedition in 2021. Interpretation of seismic records show prominent sedimentary wedges (up to 1.5 km thick) on the upper continental rise that formed during preglacial time. The outer part of the wedges formed under the influence of bottom currents, the earliest development of which is thought to be in the Late Eocene and Early Oligocene. The dominant facies of the middle-lower continental rise in the synglacial (post-Eocene) strata are channel/levee systems reworked to varying degrees by bottom currents. The most prominent of these systems is the 500 km long Wild Canyon flanked by up to 3 km thick Wilkes and Darnley drifts located in the eastern part of the study region. The Darnley Drift started to form in the Middle Miocene by the interaction of turbidity flows, induced by Cape Darnley Bottom Water (CDBW), and bottom currents. In other places, bottom currents produced isometric and oval-shaped, 60-100 km across, mounded drifts (isolated within overbank deposits). Abyssal plain is dominated by the extensive sheeted drifts of up to 300-400 m thick. The cores of modern and paleo contour currents are well identified on MCS sections by moats which are allow us to reconstruct the pattern of the bottom water circulation. It originated in the Late Eocene and the Early Oligocene, but developed most extensively (from the continental slope to the abyssal plain with westward flow direction) in the Middle and Late Miocene.

21

Wet and dry snow radar zones variability in the North of the Antarctic Peninsula using a cloud computing environment

Mr Filipe Daros Idalino^1,2, Ms Katia Kellem Da Rosa^1,2, Mr Fernando Luis Hillebrand^3,2, Mr Jorge Arigony-Neto^4,2, Mr Claudio Wilson Mendes-Junior^1,2, Mr Jefferson Cardia Simões^1,2

¹UFRGS, Porto Alegre, Brazil. ²Centro Polar e Climático, Porto Alegre, Brazil. ³IFRGS, Bento Gonçalves, Brazil. ⁴FURG, Rio Grande, Brazil

Abstract

This work investigated the annual variations in dry snow (DSRZ) and wet snow radar zones (WSRZ) in the north of the Antarctic Peninsula between 2015-2023. A specific code for snow zone detection on Sentinel-1 images was created on Google Earth Engine by combining the CryoSat-2 digital elevation model and air temperature data from ERA5. Regions with σ⁰ values exceeding -6.5 dB were considered the extent of surface melt occurrence, and the dry snow line was considered to coincide with the -11 °C isotherm of the average annual air temperature. The annual variation in WSRZ exhibited moderate correlations with annual average air temperature, total precipitation, and the sum of annual degree-days. However, statistical tests indicated low determination coefficients and no significant trend values in DSRZ behavior with atmospheric variables. The results of reducing DSRZ area for 2019/2020 and 2020/2021 compared to 2018/2018 indicated the upward in dry zone line in this AP region. The methodology demonstrated its efficacy for both quantitative and qualitative analyses of data obtained in digital processing environments, allowing for the large-scale spatial and temporal variations monitoring and for the understanding changes in glacier mass loss.

22

Lower tropospheric halogen chemistry over Antarctica

Dr Anoop Mahajan¹, Ms Shrutika Wagh¹, Dr Rafael Fernandez², Dr Silvia Bucci³, Dr Steffan Beirle⁴, Dr Thomas Wagner⁴, Dr. Alfonso Saiz-Lopez⁵

¹Indian Institute of Tropical Meteorology, Pune, India. ²Institute for Interdisciplinary Science, National Research Council, FCEN-UNCuyo, Mendoza, Argentina. ³Department of Meteorology and Geophysics, University of Vienna, Vienna, Austria. ⁴Max-Planck-Institut für Chemie (MPI-C), Mainz, Germany. ⁵Institute of Physical Chemistry Blas Cabrera, Madrid, Spain

Abstract

Halogens play an important role in the lower troposphere, affecting the oxidation capacity and causing new particle formation. Observations of halogen compounds are rare in the Antarctic and have been focused on the West Antarctic, where high levels of iodine oxide (IO) and bromine oxide (BrO) have been observed. Here, we present observations of IO and BrO from the Indian Antarctic station, Bharati (69.41°S, 76.19°E), in East Antarctica. BrO is present at high levels in Spring, similar to observations in West Antarctic, peaking at 10.21 ± 4.38 pptv for clear sky conditions and 33.15 ± 2.23 pptv for cloudy conditions. BrO was not observed outside the Spring season, suggesting first-year sea ice is crucial to its emissions. IO is present at much lower concentrations (peak ~2 pptv) than in West Antarctica (peak ~20 pptv), showing that halogen chemistry has large heterogeneity in this region. We also present the first vertical profile observations of both molecules, which show higher concentrations in the boundary layer, with strong decreasing gradients above it. Modelling simulations, which include emissions parameterised using sea ice concentrations, sea ice thickness and chlorophyll concentrations, replicate the observations, showing that sea ice regions are the primary source for both halogens in Antarctica. At concentrations observed at Bharati, halogens lead to the destruction of ozone at a peak rate of 2.9 ppbv day^-1, which is much lower than the destruction rate of 13.75 ppbv day^-1 reported in West Antarctica.

25

Automation and Advancements: Satellite Tracking in Antarctica for Enhanced Scientific Discoveries.

Mr Chinmay Kumar Patra¹, Mr Sahal Mohammed M.N.², Mr Sudhakar Kandukuri³

¹Space Applications Centre ISRO, Ahmedabad, India. ²ISRO Telemetry Tracking and Command Network, Bengaluru, India. ³National Remote Sensing Centre, Hyderabad, India

Abstract

The harsh conditions of Antarctica, characterized by extreme temperatures, isolation, and limited accessibility, have historically posed formidable obstacles to data collection and observational studies. The ground station at polar region acts as a last point to collect satellite and payload data for the polar orbiting satellites, as all the polar orbits converge at the polar region. This research initiative addresses these challenges by establishing a state-of-the-art ground station equipped with automated satellite tracking capabilities, communication protocols, and data processing algorithms, allowing for remote and continuous monitoring of satellites in polar orbits. The study aims to propel the remote sensing research forward by introducing automated satellite tracking systems in Antarctica, leveraging cutting-edge technologies to overcome geographical challenges and remoteness. The primary objective of this endeavor is to enhance the utilization of ground station in Antarctica, by reducing the manpower. Automated tracking not only reduce the manpower at ground station but also ensures a seamless flow of data, enabling real-time analysis and interpretation of data. The research explores the implications of the automated ground station for various scientific disciplines, including climate science, glaciology, disaster management and environmental monitoring. Moreover, the paper delves into the integration of emerging technologies such as artificial intelligence and machine learning into the automated tracking system. These technologies play a pivotal role in optimizing data processing, adapting to dynamic environmental conditions, and enhancing the predictive capabilities of the satellite tracking infrastructure. The synergy between automation and emerging technologies not only elevates the precision of scientific measurements but also opens new avenues for global collaborations and data-driven discoveries. In conclusion, it envisions a transformative era for polar research from a polar region.

27

Hydroclimate changes in Antarctica during 1900-2014

Mrs Natália Silva, Doctor Ilana Wainer

University of Sao Paulo, Sao Paulo, Brazil

Abstract

The hydroclimate of southern high latitudes impacts the Antarctic Ice Sheet (AIS) and, by consequence, the global climate. In the AIS, precipitation (PPT) is related to the surface mass balance, and it has increased over the past centuries as a response to global warming. In particular, this upward PPT trend accelerated in the late 20th Century, when anthropic activity became relevant in forcing the climate. Using data from 23 CMIP6 models and seven reanalyses, we described PPT changes Antarctica considering the periods “before” and “after” the year 1980. South of 60^oS, the reanalyses ensemble mean indicated a PPT trend increase of 60% when comparing the previous period (1900-1979) with the contemporary (1980-2014); The multi-model mean captured a sevenfold acceleration in PPT trends from the first to the later period. However, PPT changes were spatially heterogeneous: while a general increase occurred south of 60° S, western Antarctica became dryer. We also analyzed the Southern Ocean's sea surface temperature (SST) and atmospheric circulation, two principal modulators of the Antarctic PPT. We found that PPT in Antarctica throughout 1900-2014 was primarily determined by changes in the atmospheric circulation rather than variations in the Southern Ocean's SST.

30

Age of recruitment in the Antarctic Shag at Harmony Point

Degree in Biological Sciences Antonella Farace Rey^1,2,3, PhD Mariana Juáres^2,3,4, PhD Mercedes Santos⁵, PhD Ricardo Casaux⁶

¹Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Evolución y Genética, Buenos Aires, Argentina. ²Departamento Biología de Predadores Tope, Instituto Antártico Argentino, 25 de mayo 1143, B1650CSP, San Martín, Buenos Aires, Argentina. ³Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina. ⁴Laboratorios Anexos, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 N° 3, B1904AMA, La Plata, Buenos Aires, Argentina. ⁵Instituto Antártico Argentino, 25 de mayo 1143, B1650CSP, San Martín, Buenos Aires, Argentina. ⁶Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET–UNPSJB), Roca 780, 9200, Esquel, Chubut, Argentina

Abstract

A decline in the number of breeding pairs was observed between 1995 and 2015 in the Antarctic Shag (Leucocarbo bransfieldensis) colony at Harmony Point (Nelson Island, South Shetland Islands, Antarctica). Such process was attributed mainly to the impact derived from the fish fishery developed in Antarctica in the late 1970s and early 1980s. It was indicated that the Antarctic Shag reaches sexual maturity at 4 years of age and that the age of recruitment strongly influences the population trend. Thus, we analyzed the age at recruitment of chicks born in this colony. For this purpose, we followed the chicks banded between 2001 and 2004 (n = 26), because of the continuity of the sampling. It was observed that the most frequent age of recruitment was 2 and 3 years without significant differences between the sexes (GLM with Poisson distribution; p-value > 0.05). Strikingly, one female was observed breeding at one year of age. This early recruitment may be a response to the continued decline in the number of pairs observed in this colony. These types of studies are important because they allow us to better understand the population dynamics of a species already affected by anthropogenic activities.

31

Exploring Variability in Bromocarbons Production during the Austral Winter at King George Island, Antarctica

PROFESSOR Justin Sentian¹, ASSOC. PROFESSOR RAUL CORDERO², Dr Alesandro Domino³, Dr Jackson Hian Hui Chang¹, Associate Professor Chee Fuel Pien¹, Mr Franky Herman¹, Mr Chang Hee Kuan⁴

¹Universiti Malaysia Sabah, Kota Kinabalu, Malaysia. ²University of Santiago, Santiago, Chile. ³National Institute for Environmental Studies, Ibaraki, Japan. ⁴Axiom laboratory, Singapore, Singapore

Abstract

Bromocarbons, characterised as organic compounds containing bromine, are abundant in the oceans and predominantly produced by macro- and microalgae through enzymatic processes. The most abundant among these brominated organics are bromoform (CHBr₃), dibromomethane (CH₂Br₂), dibromochloromethane (CHBr₂Cl), and bromodichloromethane (CHBrCl₂). A recent investigation in the coastal area of the Weddell Sea discovered that the emissions of bromoform during the austral winter were ten times higher compared to those observed during the austral summer in the Amundsen Sea of Antarctica. Further study was conducted during the austral winter in a semi-enclosed coastal bay located within Maxwell Bay on King George Island, aiming to comprehensively investigate the recently identified potential source of bromocarbons by examining their variations in seawater, sea ice, and the air. Based on the preliminary results, there are higher levels of CH₃Br₂ and CHBr₃ in sea ice compared to seawater. Additionally, these levels are more than double the concentration observed in the previous study conducted over the Weddell Sea. Meanwhile, the concentrations of these compounds in the air exhibit variability, with slightly increased emissions towards the end of the winter period. These discoveries affirm that winter sea ice can significantly contribute to atmospheric bromine, especially at larger magnitude in semi-enclosed coastal regions compared to inland and open-sea areas. This further suggests that there may be important implications for atmospheric chemistry and climate on a broader scale.

32

Using Ecopath with detail zooplankton groups to evaluate the effect of reductions of sea ice in the food web structure.

Camila Cataldo-Mendez^1,2,3, Associate Professor Kerrie Swadling^1,2, Dr Roshni Subramaniam⁴, Dr Christine Weldrick^1,2

Abstract

Zooplankton, as secondary producers, are crucial in marine food webs. Yet, they are often oversimplied in food web models. Due to its essential role in Antarctic food webs, Antarctic krill, Euphausia superba, has been extensively studied, however there are gaps in understanding their interactions with sea ice, which is an important aspect of their life cycle. Additionally, other krill species - such as E. crystallorophias and E. triacantha, which are especially important for studying Antarctic food webs in regions where sea ice is seasonally present, have been overshadowed, limiting predictability for food web models due to limited high-resolution data. This is true not only for krill species but also for other zooplankton taxa, these are generally oversimplified in models but are yet important for understanding overall food web structure and function.

The overarching aim of this study is to incorporate high-resolution diet data collected with stable isotope analysis and DNA metabarcoding on krill (E. superba, E. triacantha and E. crystallorophias) and other important zooplankton taxa (pteropods, copepods, salps, among others) to provide a better understanding of zooplankton diets and integrate this data into a mass-balanced (Ecopath with Ecosim) food web model for East Antarctica. This will allow for enhanced predictions of food web response to environmental change, with a particular interest on identifying the possible effect of sea ice reductions on the food web.

33

The staggered retreat of grounded ice in Ross Sea, Antarctica since the LGM

Matthew Danielson, Dr. Philip Bart

Louisiana State University, Baton Rouge, USA

Abstract

The retreat of the West Antarctic Ice Sheet (WAIS) in the Ross Sea after the LGM was more significant than for any other Antarctic sector. Here we combined the available chronology of retreat with new mapping of seismically resolvable grounding zone wedges (GZWs). Mapping GZWs is important because they record the locations of former stillstands in the extent of grounded ice for individual ice streams during the overall retreat. Our analysis shows that the longest stillstands occurred early in the deglacial and had millennial durations. Stillstands ended abruptly with retreat distances measured in the tens to hundreds of kilometers creating deep embayments in the extent of grounded ice across the Ross Sea. The location of embayments shifted through time. The available chronological data shows that cessation of WAIS and East Antarctic Ice Sheet (EAIS) stillstands were highly asynchronous across at least five thousand years. There was a general shift to shorter stillstands throughout the deglacial. Asynchronous collapse of individual catchments during the deglacial suggests that the Ross Sea sector would have contributed to multiple episodes of relatively small amplitude, sea-level rise as the WAIS and EAIS retreated from the region. The high sinuosity of the modern grounding zone in the Ross Sea suggests that this style of retreat persists.

34

Environmental risk assessment in soils of East Antarctica oases: monitoring, trends, natural and human-induced effects

Ivan Alekseev¹, Dr. Elena Grek^2,1, Antonina Chetverova^3,1

¹Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation. ²State Hydrological Institute, St. Petersburg, Russian Federation. ³St. Petersburg University, St. Petersburg, Russian Federation

Abstract

Although Antarctica is considered as one of the most pristine areas on Earth, increasing rates of human presence raised numerous environmental risks in recent decades. Soil samples from topsoil horizons were collected from Larsemann Hills, Pravda coast and Fulmar Island, East Antarctica during 63th and 69th Russian Antarctic Expedition to analyze the accumulation levels 8 trace elements and 17 polycyclic aromatic hydrocarbons (PAHs) across different landscapes. Various human activities have been found to be responsible for increase of metal levels in studied environments. Our study also revealed a specific role of ornithogenic factor and moss cushions in distribution of contaminants. Ornithogenic soils were characterized by higher rates of accumulation of some trace elements (especially zinc and copper) compared to other sites without significantly visible traces of guano inputs, which lead to higher values of soil pollution indices in natural soils. Generally, geoaccumulation index (Igeo) for trace elements were under or slightly above the 0 level, indicating low to moderate pollution of the studied soils. Results of principal component analysis revealed the necessity for further detailed research on interactions of trace metals with soil organic matter for better understanding of their biogeochemistry in Antarctic environments. Low-molecular PAHs such as acenaphthylene and fluorene were found in highest contents among PAHs detected. Our results showed that the most of studied sites are characterized by predominance of light PAHs, which compose the natural organic matter. This study has been supported by the grant of the Russian Scientific Foundation, project № 24-27-00361.

35

Soil organic matter in East Antarctica oases: molecular composition and variability at different bioclimatogenic and geogenic conditions

Dr. Elena Grek^1,2, Ivan Alekseev², Antonina Chetverova^3,2

¹State Hydrological Institute, St. Petersburg, Russian Federation. ²Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation. ³St. Petersburg University, St. Petersburg, Russian Federation

Abstract

Antarctic soils are usually found as weakly developed, however recent studies indicated the significant variability in soil forming conditions across the sixth continent as well as considerable soil diversity. The identification of pedogenetic processes in Antarctica is crucial for understanding not only the current state of its environment, but also for better understanding of soil development on Earth through time. This study is aimed at the detailed investigation of micromorphological features, molecular and fractional composition of soil organic matter in soil and soil-like bodies of two oases of East Antarctica - Larsemann Hills and Bunger Hills. Soil fabric was usually characterized by predominance of grains of quartz, feldspars, and other primary minerals with angular shapes indicating relatively weak degree of alteration. Organo-mineral interactions were mostly associated with the development of biofilms in the topsoil horizons of soils developed in wind shelters and wet walleys. Differences in elemental composition and atomic ratios of O/C, H/C and C/N, as well as the dominance of the peripheral part over aromatic fragments in humic acids have been shown. This is due to the extremely low content of phenylpropane structural fragments in organic residues of mosses and lichens. We also observed that humification in fine earth formed under penguin rookeries, wind shelters is carried out more intensively. Humification process occurs in soils and soil-like bodies of East Antarctica even in conditions of almost complete absence of aromatic phenylpropane precursors. This study has been supported by the grant of the Russian Scientific Foundation, project № 24-27-00361.

37

How does climate modes influence the transport of Circumpolar Deep Water onto the Bransfield Strait?

MSc. Brendon Damini, Dr. André Brum, Dr. Rodrigo Kerr, Dr. Mauricio Mata

University of Rio Grande, Rio Grande, Brazil

Abstract

The Bransfield Strait, located in the Northern Antarctic Peninsula, is a critical research area for investigating the effects of climate change. Its unique position as a transition zone exposes it to various oceanographic and biogeochemical processes. This complexity arises from the convergence of distinct water masses, the Dense Shelf Water (DSW) from the Weddell Sea and the Circumpolar Deep Water (CDW) from the Bellingshausen Sea, which shape its complex circulation dynamics. The transport of DSW into the Bransfield Strait primarily occurs through the Antarctic Coastal Current near Joinville Island. Conversely, the CDW is introduced into the Strait via several pathways, including passages between the South Shetland Islands, the Drake Passage south of King George and Elephant Islands, and towards Gerlache Strait. To understand these water masses advection, we calculated baroclinic velocities and water masses transports using a dynamic method applied to longitudinal hydrographic sections repeatedly collected by the High Latitude Oceanography Group from 2003 to 2019. Our results show a direct link between the strength of these water mass transports and atmospheric conditions, particularly influenced by climate modes (i.e., the Southern Annular Mode – SAM and the El Niño–Southern Oscillation – ENSO). For instance, positive SAM and negative ENSO phases lead to increased westerly winds that drive the SAACF southwards and increase wind stress over the peninsula, which in turn influences the advection of CDW into the Bransfield Strait. Furthermore, our study emphasizes that CDW might enter the Bransfield Strait between King George and Elephant Islands, and that transport may be more intense (reaching values around 2 Sv) during periods of positive SAM and negative ENSO phases. These observed changes are important to improve our understanding of local circulation patterns and the underlying mechanisms, as they directly influence the physical and biogeochemical properties of the region.

38

Effect of Extreme Environment and Isolation on Subjective Time Estimation in Antarctica During Summer: A Cross Sectional Investigation

Professor Azizuddin Khan

Indian Institute of Technology Bombay, Mumbai, India

Abstract

Antarctica provides an excellent opportunity to study the effect of the environment on human behavior. However, not much work has been done to understand the impact of extreme environmental and living conditions on time estimation in Antarctica. Accurate time estimation is a prerequisite for optimal performance. Antarctica's environment such as extreme weather, confinement, isolation, absence of movement, and twenty-four hours of daylight affects human behavior. It also affects time estimation. Several environmental and social factors influence interval timing. The present study aimed to investigate the effect of extreme environment and isolation on time estimation in Antarctica. The data was the collection from three different locations, namely: members of an expedition on the ship from Cape Town, South Africa (N=19) to Antarctica, Maitri station (N=20), and Bharati station (N=19) at Antarctica. A total of fifty-seven expeditions participated in the study. The design of the first part of the experiment was a 3 (Group: Ship vs. Bharati vs. Maitri; between subjects) × 2 (Method of judgment: verbal time estimation and reproduction; within subjects) factor split-plot design. Analyses of variance were employed to analyze the data. Results revealed that there was an overestimation of time at Bharati station as compared to the expeditions performance at Maitri station and on the Voyage. At the Bharati station, expeditioners were having more time, low interaction among themselves as compared to Maitri station and Voyage. Therefore, the results could be explained on the basis of less engagement of day to day activities and high boredom the Interactions among them was quite less as compared to expeditioners at Maitri and Voyage. Expeditioners at Voyage reported less error in both verbal estimation and reproduction of time method as compared to expeditioners at Bharati and Maitri stations.

Keywords: Environment, Extreme weather, Isolation, Verbal estimation, Interval timing

44

Microbiome and Resistome of Migratory Birds from the Arctic, Antarctic and Tropical Regions

Mr Akhil Prakash E¹, Ms Tereza Hromádková², Dr Maarten J.J.E. Loonen³, Dr Jabir Thajudeen⁴, Ms Farsana Alangadan¹, Dr Mohamed Hatha A A¹

¹Cochin University of Science and Technology, Kochi, India. ²University of South Bohemia, Branišovská, Czech Republic. ³University of Groningen, Groningen, Netherlands. ⁴National Center for Polar and Ocean Research, Vasco-da-Gama, India

Abstract

Antibiotic resistance poses a substantial threat to human health, stemming from the widespread use and misuse of antimicrobial drugs in both human healthcare and livestock management. Migratory birds are implicated in the dissemination of antibiotic resistance, as recent studies highlight their gut microbiota as a reservoir of antibiotic resistance genes (ARGs). This research focuses on faecal samples from three migratory bird species: Arctic Tern (Sterna paradisaea) from the Arctic, Brown Headed Gull (Chroicocephalus brunnicephalus) from tropical regions, and South Polar Skua (Stercorarius maccormicki) from Antarctica. Analysis of faecal metagenomes of these birds identified a total of 3,278 distinct genera of bacteria among the faecal samples of these birds, with Firmicutes dominating across all species. In tern samples, 760 genera were identified, with Arthrobacter, Clostridium, Carnobacterium, and Yersinia as the most prevalent. Gull samples displayed the highest genus diversity (1782 genera), primarily Vagococcus and Enterococcus. Skua samples contained 736 genera, with Bacillus, Escherichia, and Clostridium as predominant. A total of 127 ARGs were identified, with terns exhibiting occurrences of highly diverse ARG’s, particularly those involved in multidrug resistance, polymyxin, MLS, beta-lactam, and bacitracin antibiotics. E. coli from the faecal samples of skuas showed relatively high degree of resistance, notably multidrug, polymyxin, MLS, tetracycline, bacitracin, and beta-lactam antibiotics. The primary resistance mechanisms observed were efflux pumps for multidrug resistance, followed by MLS and polymyxin resistance in gulls and the highest resistance showed by E. coli. These findings emphasize the role of migratory birds in carrying antibiotic-resistant bacteria, contributing to the spread of ARGs across diverse environments, including polar regions.

45

Antarctica: stories of women explorers in the heart of the planet. Science journalism and 50 testimonies from Science, Education, Art, Army and Politics in Chile. A first-person view

Antarctica: stories of women explorers in the heart of the planet. Scientific journalism and 50 testimonies from Science, Education, Art, Politics and Armed Forces of Chile Nadia Politis

ACHIPEC: Chilean Association of Journalists and Professionals for Science Communication, Santiago, Chile

Abstract

Studying at the mythical Chilean school in Antarctica, diving in waters with temperatures of -1 °C, or flying in a military plane to the South Pole, may seem like the work of a select group of people, but nowadays they are carried out by different groups of women. Professionals who have developed their passion in the southernmost place in the world.

With the aim of rescuing these stories, the book "Antarctica: stories of female explorers in the heart of the planet", written by the Chilean scientific journalist Nadia Politis, was born. The author interviewed more than 50 women, between the ages of 15 and 95, who, at different times in Chile's history (and today) have been involved with the white continent.

The result is a collective story, full of emotion and adventure, which reflects on the major issues facing Antarctica (climate change, invasive species, earthquakes and frontier science), along with a woman's perspective on the challenges in the field, stereotypes and personal dreams.

How to add humanity, personal perspectives and a critical view to Antarctica? Science journalism is proposed as a strategy.

49

Land/ocean mask generation using Sentinel-2 imagery and cloud computing

Professor Eliana Lima da Fonseca, Professor Jefferson Cardia Simões

Centro Polar e Climatico – Federal University of Rio Grande do Sul, Porto Alegre, Brazil

Abstract

Due to its small cartographic scale (low detail levels), the Antarctica vector database can not used to separate the land areas from ocean areas in the satellite images because the vector borders don't match with the natural land borders observed at these images. An alternative is to create a mask using the information from the satellite images to filter the satellite images, which must include all the land/ocean borders for the continents and the islands, even for the small rocks islands, with the same detail level observed at these images. A land/ocean mask was generated using the Sentinel-2 images, based on the water reflectance patterns in the infrared band, specifically the “water vapor band” (B9), centered at 945nm and 943.2nm for Sentinel 2A and 2B, with 60m spatial resolution. At these wavelengths, the liquid water reflectance is near zero, and the cloud and snow reflectance are around 0.7. A minimum value composite image for B9 was computed by selecting the minimum reflectance value registered for each pixel for the whole time series (from March 2017 until now). With this approach, every water pixel acquired without ice or cloud cover, at least once during the time series, will be filled with a TOA reflectance value around zero, due to the water spectral reflectance pattern. The B9 minimum value composite image had its values remapped, building a binary image to identify the ocean and land areas. With this approach, we could eliminate the cloud and cloud-shadow pixels to map the borders and exclude even those pixels with phytoplankton over the ocean.

51

Variability and drivers of phytoplankton productivity in the Indian Sector of the Southern Ocean: Implications for carbon cycle and climate change

Mr. Sunil Kumar Padhi, Dr. Sarat Chandra Tripathy, Dr. Sudarsana Rao Pandi

National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, India

Abstract

Oceanic phytoplankton productivity (PP) is crucial for unraveling the complexities of the global carbon cycle and Earth’s interconnected systems, which regulate atmospheric CO₂ through intricate oceanic systems. Despite its significance as a potential carbon sink, the Southern Ocean (SO) remains under-sampled due to various logistical challenges. Using a dataset over a decade, the present study aims to elucidate the variability of water column PP in the Indian Sector of the Southern Ocean (ISSO) by examining associated physicochemical parameters and physiological conditions of phytoplankton that drive this variability. Results revealed the nutrient limitation in the region north of the Sub-Antarctic Front (SAF), while the region south of SAF exhibited light limitation coupled with intense grazing by mesozooplankton. Coastal waters exhibit higher PP, characterized by the prevalence of large phytoplankton. Among the fronts, SAF displayed maximum productivity, while the Polar Front 2 (PF-2) recorded the lowest. Weak stratification leading to the mixing of nutrient-rich Antarctic bottom water supported high production in SAF. Whereas the deepening of mixed layer depth, due to the high-magnitude wind in the PF-2, hampered the light availability in the water column, and led to low production in this region. The Chl:C ratio, a proxy for phytoplankton physiological status, indicated balanced growth conditions in the frontal regions, except north of the Sub Tropical Front (STF), where the oligotrophic condition supports the growth of picoplankton, subjected to high grazing by microzooplankton leading to unbalanced growth. Conversely, in the coastal waters, the phytoplankton experienced physiological stress and unbalanced growth due to low temperature and low light conditions. Model-based estimates of PP highlighted the efficacy of the CbPM in estimating net PP in these polar waters, surpassing the VGPM and Eppley-VGPM. Notably, all model-based PP estimates significantly improved with in situ chlorophyll as input instead of satellite-retrieved chlorophyll.

53

Soil microbial community structure of Greenwich Island, maritime Antarctica and their response to dissolved nitrogen dioxide in water

Assoc.Prof. SITI ALIAS^1,2, Mr. Sanjeev Kumr³, Dr. Nurlizah Abu Bakar¹, Dr. Mohammed Rizman-Idid^1,4, Assoc.Prof. Geok Yuan Annie Tan¹, Dr. Marcelo Gonzales⁵, Dr. Abiramy Ramakrishnan⁶

¹Universiti Malaya, KUALA LUMPUR, Malaysia. ²National Antarctic Research Centre, Kuala Lumpur, Malaysia. ³Universiti Malaya, Kuala Lumpur, Malaysia. ⁴National Antarctic Research Centre, KUALA LUMPUR, Malaysia. ⁵Instituto Antarctico Chileno, Punta Arenas, Chile. ⁶MAHSA University, Selangor, Malaysia

Abstract

Since the 1950s, one of the world’s fastest regional warming has been recorded in the Antarctic Peninsula, with annual temperatures increasing by up to 0.56°C per decade. Furthermore, precipitation have increased over the Antarctic Peninsula region. In view of the anthropogenic threats to climate change, this study aims to investigate i) the fungal and bacterial community structure in homogenized soil samples of Greenwich Island, maritime Antarctica and ii) how such microbiota may be affected by rainfall with dissolved nitrogen dioxide (NO₂). In total, 11 soil samples collected across Greenwich Island which included Ambato Point, Maldonado Base, Dee Island, Barrientos Island and Cecilia Island were combined, homogenized and total genomic DNA was extracted from which metagenomic bacterial and fungal libraries using V3-V4 and ITS1 regions, respectively, were constructed. Microbiota results revealed a total of 3,897 amplicon sequence variants (ASVs) recorded for bacteria and 1,138 ASVs for fungi. Of that, 27 bacterial and five fungal phyla were identified from metagenomic libraries of the V3-V4 hypervariable region of the 6S rRNA gene and the ITS1 region, respectively. The fungal phylum was dominated by Ascomycota (68%), Mortierellomycota (17%) and Basidiomycota (11%). The bacterial phylum was accounted by Actinobacteriota (43%), Chloroflexi (29%) and Proteobacteria (10%). Overall, bacteria showed greater species diversity, richness, and evenness than fungi. In order to explore the effects of rainfall with dissolved NO₂, a laboratory microcosm experiment was established. Soil samples were be treated with distilled water containing various concentrations of dissolved NO₂. Results from the microcosm experiment will be discussed, particularly in providing insights towards the responses of soil microbes to environmental changes in Antarctica, specifically on their roles and ecological functioning in the Antarctic ecosystems.

54

Pattern of the variation of the TEC extracted from the GPS, IRI 2016, IRI-Plas2017 and NeQuick 2 over polar region, Antarctica

Yekoye Tariku

Space science and geospatial institute, Addis Ababa, Ethiopia

Abstract

As a result of the complex and typical behavior of the earth's magnetic field, the high latitude ionospheric parameters (such as the Vertical Total Electron Content, VTEC) are very dynamic. Thus, this study mainly focuses on the pattern of variation of the VTEC inferred from the GPS, IRI 2016, IRI-Plas 2017 and NeQuick 2 with different height over Antarctica during 2011–2017. It has been shown that the GPS-derived (GPS VTEC) and modelled (IRI 2016, IRI-Plas 2017 and NeQuick 2) VTEC do not show significant variations in the hourly values.This shows that the solar irradiance mostly responsible for the ionization of neutral molecules in the earth's upper atmosphere does not show significant hourly variation in the region. Moreover, the GPS VTEC values are larger than the modelled values on most of the hours with the highest Root-Mean-Square Deviations, RMSD (close to 14 TECU) resulting from underestimation of the VTEC by the IRI 2016 model being observed in the March equinox in 2014. On the other hand, relatively small RMSDs (less than 1 TECU) are observed on most of the hours in using all models, demonstrating that the models’ performance is good with the NeQuick 2 model showing the best followed by the IRI-Plas 2017. Similar and smooth VTEC variation patterns are also observed in the bottom-side, topside and plasmaspheric layers during both the high and low solar activity years. This shows the TEC variation does not have significant impact on the signal propagated through the ionosphere in the polar region. Besides, the highest and lowest contributions of the TEC have been seen in the topside and plasmaspheric layers, respectively. The topside TEC contribution generally increases when the solar activity (or solar irradiance) increases; while, the plasmaspheric TEC contribution enhances when the solar activity (or solar irradiance) drops.

56

The Australian Antarctic Territory Sound Map

Professor Philip Samartzis

RMIT University, Melbourne, Australia

Abstract

The Australian Antarctic Territory Sound Map

Contemporary audio technology provides the capacity to record in places seldom seen or heard. By being in the world sound artists bear witness to change that is usually incremental but increasingly exponential evidenced by accelerated social and environmental transformation. The practice of fieldwork offers a mechanism to engage with and register change, and to preserve and advocate for these mutable ecologies and their attendant stakeholders. The recordings afford audiences a chance to experience often highly regulated, hard to access places through different aesthetic and narrative forms, and immersive and affective encounters.

Fieldwork demands highly adaptive responses to negotiate indeterminate conditions and hidden tensions. Rather than consider these as undesirable, fieldwork offers an opportunity to observe and contest dominant narratives, and through improvised responses and participatory practices ameliorate aleatoric forces. These destabilising factors become more acute when extreme climate and weather, human action, and social and cultural dissonance converge at the margins of our planet. A zone of rupture and divergence marked by tension, disquiet, and exclusion.

The ways people live and work in remote places progressively resembles the broader contemporary experience, in which strict protocols and hyper-vigilance is used to mitigate risk. The unpredictable nature of life in extremis that necessitates constant adaptation is in many ways how we live on the rest of the planet where our assumptions are regularly tested. The resilient communities who occupy these distant and fragile environments provide models of resistance that can help deepen understanding of loss and decay. Sound artists play an increasingly vital role in observing and recording the tension between climate, landscape, technology, and human action, to demonstrate the interconnectedness of things.

61

Short-term changes in summer sea-air CO₂ exchanges along the northern Antarctic Peninsula

MSc. Matheus Batista¹, Dr. Thiago Monteiro¹, Dr. Brenno J. Silva¹, MSc. Andrés Piñango¹, Dr. Andréa Carvalho², Dr. Rodrigo Kerr¹

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Universidade Federal do Ceará, Fortaleza, Brazil

Abstract

Sea-air CO₂ exchanges in coastal regions of Antarctica are frequently studied during the austral summer, mainly due to the difficulty of sampling in other seasons. It is widely known that during summer, such coastal regions behave as zones of net CO₂ ocean sinks. We investigated sea-air CO₂ exchanges along the northern Antarctic Peninsula (NAP) marine environments during January-March 2019 and showed that, even during summer, this region can act as an CO₂ outgassing zone. The CO₂ partial pressure difference between the ocean and atmosphere (ΔpCO₂) along the NAP environments averaged –17 ± 47 µatm. The average CO₂ sink behaviour was biased by the average ΔpCO₂ of February (–52 ± 45 µatm) and March (–17 ± 39 µatm), since in January the average ΔpCO₂was 3 ± 43 µatm, revealing that in this month the NAP behaved as a source of CO₂ into the atmosphere. This difference in ΔpCO₂ behaviour between the sampled months is observed in different sub-regions of the NAP, such as in the western basin of Bransfield Strait, where the average ΔpCO₂ in January was 13 ± 41 µatm, in February it was –44 ± 32 µatm and in March it was –28 ± 24 µatm. This huge difference in the behaviour of sea-air CO₂ exchanges is likely associated with rapid hydrodynamic and biogeochemical changes throughout the austral summer. Such changes are often neglected in studies that investigate sea-air CO₂ exchange without considering short-term changes among summer months. These results highlight the importance of expanding the investigation of short-term processes in biogeochemical studies to improve our understanding of the carbon cycle in Antarctica coastal regions.

62

Two decades of sea-air CO₂ exchanges in the northern Antarctic Peninsula (1999-2019): Spatiotemporal variability and pCO₂ drivers

Dr. Thiago Monteiro, B.Sc. Anderson Braga, Dr. Rodrigo Kerr

Universidade Federal do Rio Grande, Rio Grande, Brazil

Abstract

Among the regions of the Southern Ocean, the northern Antarctic Peninsula (NAP) is known as a hotspot suffering climate change pressures. Nonetheless, an overview of the spatial and temporal variability of sea-air CO₂ fluxes (FCO₂) along the NAP is still poorly understood. Therefore, we investigated the variability of FCO₂ during the austral summer, from 1999 to 2019, along the NAP. Changes in dissolved inorganic carbon were identified as the main driver of interannual variability in sea surface CO₂ partial pressure (pCO₂). This indicates that CO₂ uptake/release is controlled by processes other than changes in temperature, such as photosynthesis, upwelling and air-sea CO₂ exchanges. We identified two cycles of FCO₂ variability with periodicities of 4 years until 2010, and an intensification to 2 years mainly from 2011 onwards. In general, summer sea-air CO₂ exchanges along the NAP have been near equilibrium over the past two decades, with an average FCO₂ of 0.4 ± 1.1 mmol m⁻² d⁻¹. Furthermore, we observed a change from a CO₂ outgassing behaviour of 0.31 ± 0.70 mmol m⁻² d⁻¹ in the first decade investigated (1999-2009) to a CO₂ ingassing of –1.24 ± 0.92 mmol m⁻² d⁻¹ from 2010 to 2019). This change occurred mainly due to the progressive increase in the atmospheric pCO₂, as we did not identify significant trends in the sea surface pCO₂ during summer. Therefore, these findings shed light on the sensitivity of sea-air CO₂ exchanges along the NAP and highlights the need to increase the studies about ocean acidification and CO₂ storage in this climate-sensitive region.

64

Visual Systems of the Cretaceous, the representation of Antarctica in the artwork Deep Connection

Dr Alejandra Pérez

Universidad de Valparaíso, Valparaíso, Chile

Abstract

"Visual Systems of the Cretaceous" refers to the visual abilities of the creatures that lived during the Cretaceous period. "Deep Connection" is an artwork that features a depiction of Antarctica and its representation in geological deep time. It showcases the connection between Antarctica and Patagonia which is supported by fossil samples of extant plants. "Deep Connection" contains three-dimensional representations of fossils of plants from the Antarctica Patagonia Paleontological Collection (CPAP) under the custody of INACH in Punta Arenas. The work of art is an installation that includes interactive projections, a book of anaglyphs, and a Virtual Reality parcours, as well as a sound itinerary that narrates different scenes of this ancestral past. The artwork was developed using open-source tools, and the starting point of the project was the question, "Who was there that was able to register the environment in the Cretaceous era, 300 million years ago, when Antarctica was adjacent to Patagonia and part of the South West Extra-Tropical Gondwana (SWETG)?" Scientific literature suggests that small dinosaurs, resembling hummingbirds, whose eyes were similar to those of lizards, along with frogs and arthropods, populated the forest. It was a heterogeneous visual environment where human sight was not present. The geological narrations found in the Antarctic distant past speak of ancient seas that were not viable, and submerged tectonic arcs moved by colossal forces that left only tiny holes for a current that started circulating the planet and changed the climate forever, until now. The register also speaks of extinction coinciding with sudden climatic changes. "Deep Connection" is an artwork that combines art and science to bring multimodal approaches to climate change by making deep time history and Antarctic fossil evidence available to the public. The presentation considers showing a Virtual Reality artwork available on a VR headset.

70

Temporal dynamics of surface microbial communities in the Northern Antarctic Peninsula: Insights from a six-year study

Laiza Cabral de Faria, Camila Negrão Signori

Oceanographic Institute of the University of São Paulo, São Paulo, Brazil

Abstract

The Antarctic microbial community is essential for the functioning of marine ecosystems and biogeochemical cycles. Bacteria, archaea, and microeukaryotes can vary temporally – between weeks, months, and/or years – and also in response to environmental factors. This study aimed to understand the temporal dynamics of surface microbial communities in the maritime area of the northern Antarctic Peninsula over six years. Total DNA was extracted from 3 L of surface seawater from ten stations, totaling 105 samples. The DNA was amplified using the universal primers 515F-Y/926R and sequenced using the Illumina HiSeq platform. A total of 19,352,395 sequences were classified into 1,646 ASVs for the 16S rRNA gene, and 1,512,668 sequences were classified into 845 ASVs for the 18S rRNA gene. The ten most abundant orders for the 16S rRNA gene were Flavobacteriales, Pseudomonadales, Bacillariophyta (Chloroplast), SAR11, Rhodobacterales, Prymnesiophyceae (Chloroplast), Rickettsiales, Nitrosopumilales, Cryptophyceae (Chloroplast), and Enterobacterales. For the 18S rRNA gene, the ten most abundant were Mediophyceae, Dinophyceae, Gymnodiniphycidae, Syndiniales, Coscinodiscophytina, Spitptrichea, Incertae_Sedis (Eukaryota), Prymnesiophyceae, Cryptomonadales, and Bacillariophyceae. The majority of the 16S rRNA community in each sample was composed of the most abundant ASVs and was more stable and homogeneous than the 18S rRNA community over the years, a similar trend found in other studies. The composition of the 16S rRNA community was similar in 2014, 2015, and 2017, while 2016 and 2019 were more similar to each other. A higher relative abundance of eukaryotes was observed in 2016 and 2019, both years with positive Southern Annular Mode. The next step is to understand how environmental factors (such as temperature, salinity, and nutrient availability) influenced these communities across different years.

71

Spatial distribution patterns of pelagic bacteria and archaea in the maritime Western Antarctic Peninsula

Luiza Soares, Laiza Cabral, Camila Signori

University of São Paulo, São Paulo, Brazil

Abstract

Marine microorganisms play a crucial role in ecosystem functioning and biogeochemical cycles, with their diversity and community structure being directly influenced by abiotic factors such as temperature. The Western Antarctic Peninsula (WAP) is a diverse region, encompassing a range of oceanic ecosystems and marked by its complexity in temperature patterns, circulation, and biogeochemistry, acting as a transition zone between subantarctic and Antarctic waters. In our study, we utilized 16S rRNA gene-based sequencing to assess bacterial and archaeal diversity in the WAP, encompassing surface to deep waters of the Bellingshausen Sea, Gerlache and Bransfield Straits, and a portion of the Weddell Sea, during the austral summer of 2016. We identified a total of 456 ASVs, excluding rare groups (<1%), with 412 belonging to the Bacteria domain (93.49%) and 44 to the Archaea domain (6.51%). The predominant microbial taxa in the WAP included Gammaproteobacteria (35.86%), Alphaproteobacteria (26.79%), Bacteroidia (23.03%), Nitrososphaeria (4.28%), and Thermoplasmata (2.24%). Statistical analysis using ANOVA revealed significant differences in Chao1 and Ace richness indices between the Bellingshausen and Weddell Seas regions (p = 0.01). These variations in microbial richness can be attributable to observed differences in average sea temperatures, with 0.66°C and -1.02°C recorded in the Bellingshausen and Weddell Seas, respectively. Previous studies suggest that environmental factors are more relevant than geographical distance in shaping the microbial community structure in Antarctic waters, which is corroborated by the obtained results.

76

POLARIN: POLAR RESEARCH INFRASTRUCTURE NETWORK

Dr. Nicole Biebow, Dr. Verónica Willmott Puig

Alfred Wegener Institute, Bremerhaven, Germany

Abstract

The polar regions play a key role in the Earth’s system. They are essential for our climate and are sentinels of climate change, human expansion, and the hunt of new resources. The polar regions are losing ice, and their oceans and land are changing rapidly. The consequences of this polar transition extend to the whole planet and are affecting people in multiple ways. Evidence-based policy recommendations are needed, but the polar regions are difficult to reach, and research infrastructures able to operate in these regions are scarce. To understand and predict key processes in the polar regions and provide evidence-based information, the polar research community needs access to world-class research infrastructure operating in these regions.

POLARIN (Polar Research Infrastructure Network) is a recently funded project by the European Union under HORIZON EUROPE Framework Programme, addressing the transnational access to polar research infrastructures (RIs), both in the Arctic and Antarctic regions. The network includes 64 top level research infrastructures: Arctic and Antarctic research stations, research vessels and icebreakers operating at both poles, observatories, data infrastructures and ice and sediment core repositories.

Challenge driven calls for proposals to access these infrastructures will ensure that the funded projects address the understanding and predicting of key processes in polar regions, contribute to larger European and international initiatives and support policy making.

In addition, POLARIN will improve online services, data access and interoperability, and will ensure that the new generations are trained to exploit the leading edge RIs.

77

Network analyses on photographic surveys reveal that predators do not structure benthos in the deep (~2000m) Powell Basin, Weddell Sea, Antarctica

Tasnuva Ming Khan^1,2,3, Huw Griffiths², Rowan Whittle², Nile Stephenson^1,3, Katie Delahooke¹, Autun Purser⁴, Andrea Manica¹, Emily Mitchell^1,3

¹University of Cambridge, Cambridge, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³University Museum of Zoology, Cambridge, United Kingdom. ⁴Alfred Wegener Institute for Marine and Polar Research, Bremerhaven, Germany

Abstract

Predator-interactions in marine ecosystems control population sizes, maintain species richness, and provide intermediate disturbance. Such ecosystem structuring interactions may be rare in Antarctic benthic communities, which are unique among marine ecosystems worldwide for their dominance of soft bodied fauna (sponges, soft and hard corals, and echinoderms) and a simultaneous paucity of shell crushing predators (sharks, rays or durophagous decapods). In the shallow benthos, instead of durophagy, important Antarctic predators such as starfish, pycnogonids (sea spiders), nemertean worms, and nudibranchs employ grazing, scavenging, or sucking strategies. Far less is known about deep sea (>1000 m) Antarctic benthic communities due to challenging nature of polar data collection, so that photographic surveys provide one of the only means of making in situ observations of these deep sea communities. We used seabed photographs of the deep (~2000m) Powell Basin, northwest Weddell Sea, taken by the Ocean Floor Observation and Bathymetry System on board the RV Polarstern (PS118, April 2019) to investigate the benthic community composition, and Bayesian Network Inference (BNI) to quantify the ecological associations between them. Photographs show that the rocky substrates of the basin support very speciose (between 10-22 morphotaxa per 1.75m x 1.75m photo quadrat) and highly abundant communities (density between ~106-~553 individuals/m²). BNI results reveal a complex network of associations between the sessile and mobile suspension and filter feeding organisms and their physical environment. Despite the presence of important mobile predators like starfish, pycnogonids and nudibranchs, ecological associations between them and other organisms were not detected in the network structure. This suggests that predator-prey interactions in the deep Antarctic Powell Basin are random and opportunistic, and do not perform the same ecosystem-structuring role they do in deep sea communities elsewhere.

84

Tectonic structure of the North-Western Weddell Sea

Dr. German Leitchenkov^1,2, Mrs. Julia Guseva³, Mr Nikita Borovkov¹

¹Institute for Geology and Mineral Resources of the World Ocean, Saint-Patersburg, Russian Federation. ²Saint-Petersburg State University, Saint-Patersburg, Russian Federation. ³Polar Marine Geosurvey Expedition, Saint-Patersburg, Russian Federation

Abstract

Deciphering the tectonic structure of the NW Weddell Sea is based on all available geophysical data in this area, including new data collected by Russian Antarctic Expeditions in 2018 and 2022. The NW Weddell Sea is located near the active boundary between the Antarctic and Scotia Plates and demonstrates complex crustal structure and evolution. The study area contains partially stretched and submerged blocks of thick continental crust (South Scotia Ridge, the South Orkney Plateau and the South Powell Ridge) with adjacent rifted and transform continental margins; small oceanic back-arc basins (Powell Basin and Jane Basin) and a volcanic palaeo-arc (Jane Arc). The opening of the Powell Basin, occurred in the Lower Oligocene-Lower Miocene (32-20 Ma; polarity chrons C11-C6AA). Continent-ocean boundaries in the Powell Basin are well defined by a marked change in basement morphology. According to the new magnetic survey integrated with previous data, the opening of the Jane Basin is characterized by ridge propagation from west to east. The extinct ridges are identified by C5ACr anomaly (14,1 Ma) in the east and C5ACn (13,9 Ma) in the west. The proposed model shows asymmetry of sea-floor spreading typical of back-arc basins. Four prominent basement highs, developed in the Jane Basin were dredged during 2022 cruise and studied mafic rocks showed that all of them (including the largest basement high between 44E and 46E, previously interpreted as the proto-arc) are alkaline in origin indicating their intraplate emplacement.

86

Will Increased Melt and Thaw Affect the Distribution of Terrestrial Micro-Invertebrates in the McMurdo Dry Valleys?

Morgan Wood¹, Dr. J. E. Barrett¹, Dr. Mark Salvatore², Dr. Byron Adams³, Dr. Eric Sokol⁴

¹Virginia Tech, Blacksburg, USA. ²Northern Arizona University, Flagstaff, USA. ³Brigham Young University, Provo, USA. ⁴National Ecological Observatory Network, Battelle, Boulder, USA

Abstract

In this study, we develop habitat suitability maps and models for micro-invertebrate taxa commonly observed in this region to investigate how changes in liquid water availability associated with a changing climate may affect soil organisms in the McMurdo Dry Valleys of Antarctica. The sparse availability of liquid water is the major control over the distribution and activity of soil organisms in the dry valleys. Developments in remote sensing techniques have expanded our capabilities to document the presence of liquid water on landscape surfaces in terrestrial Antarctica. These arid soils are inhabited by species-depauperate communities of invertebrates including nematodes, tardigrades, and rotifers of which have preferences for different environmental conditions; for example, the nematode taxa Plectus spp. are confined to saturated environments like the margins of lakes and stream channels, while others such as the nematode Scottnema lindsayae are more widely distributed throughout the dry soils. Increasing melt and thaw events are contributing to greater and longer duration of water availability in this region and climate model forecasts predict greater incidence of conditions contributing to melt and thaw. If correct, these forecasts suggest that the distributions and abundances of mesophilic and dry-adapted taxa could change. These models will be used to better understand current relationships and predict responses to future climate projection scenarios based upon extrapolations of historical extreme melt and thaw events from LTER records. A stronger understanding of how terrestrial invertebrates react to their environment will help us predict future distributions of endemic Antarctic biota.

89

Solar energy potential study and confirmation over the Indian region using INSAT data

Dr. Neeti Singh, Mr Ram Giri

India Meterological Department, New Delhi, India

Abstract

An algorithm was developed to estimate surface solar irradiance for INSAT-3D/3DR satellites under clear, cloudy skies. The resulting products, such as Insolation and Global irradiance, have been successfully utilized on a 24x7 operational basis at the India Meteorological Department (IMD) by forecasters and end-users alike. The algorithm generates irradiance (Global as well as Direct) data at a high resolution of 4 x 4 km resolution, INSAT-3D/3DR- derived products from Imager known as Global Horizontal Irradiance (GHI) and Direct Horizontal Irradiance (DHI) respectively, enabling precise estimations. This work identified and quantified the spatial variability of solar energy potential at regional or local levels. Moreover, seasonal analysis reveals positive and negative biases, with INSAT-3DR exhibiting better results than INSAT-3D across all seasons. The research findings hold immense potential for accurately estimating power consumption or utilization in the power and energy sectors. Furthermore, the estimated Global irradiance and insolation data from INSAT-3D/3DR can serve as crucial inputs for the agriculture and power sectors, offering insights into potential impacts on crop production. Moreover, a Major contributor to the Earth’s energy and radiation budget is solar insolation (INS) at the surface. It is a primary input for eco-physiological processes such as photosynthesis and evapotranspiration. It is therefore a crucial component to assess bio-fuel and bio-energy resources. Overall, this study establishes the algorithm's significance and utility, making it a valuable tool for informed decision-making in various sectors.

90

Antartic Uruguay, Dissemination is education.

Film Maker Leo Scarone

Uruguayan Antarctic Institute, Montevideo, Uruguay

Abstract

Dissemination is education.

Antarctic Uruguay is a scientific outreach project in Antarctica, supported by the Uruguayan Antarctic Institute.

Our goal is to disseminate information to all citizens of our country. As important as the content is the innovative manner in which it is presented. This project was filmed in 360 during 4 trips to the Antarctic Scientific Base.

It is permanently showcased at the Montevideo Planetarium in FullDome format. It was launched on July 27, 2023. Over ten thousand people have viewed it, mostly students.

The second stage will be itinerant and aims to reach the entire country with a room equipped with VR lenses for 20 people. This format utilizes innovative technology that is particularly appealing to children, young people and adults too.

The dissemination of scientific projects at the base is the primary objective of the project. We aim to reach the younger generation to help them understand the importance of Antarctic presence.

This year, Uruguay celebrates its 40 years of uninterrupted presence in the white continent. This project was carried out for Uruguay but synthesizes what happens in other bases, and its implementation is replicable.

Some educational institutions have expressed interest in using this content as an educational catalyst.

Base Artigas is a scientific base, thus science is the main component in communication. We strive to promote scientific training careers and showcase leading projects.

Literacy is our goal, not only for the younger generation but for the entire population. Many people are unaware that our country is present in that land.

It is a State project, a national project, a project for all.

91

Assessing foraging habits of Weddell seals in contrasting climate change impact zones of the Antarctic Peninsula

Dr. Renan Lima¹, Dr. Nico Lübcker², Dr. Silvina Botta¹, Dr. Javier Negrete^3,4, Dr. Eduardo Secchi¹, Dr. Seth Newsome²

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²University of New Mexico, Albuquerque, USA. ³Instituto Antártico Argentino, Buenos Aires, Argentina. ⁴Universidad Nacional de La Plata, La Plata, Argentina

Abstract

The Antarctic Peninsula (AP) has been particularly vulnerable to climate change, with the west (WAP) changing faster than the east (EAP). In the WAP, warming-related ecological effects have been reported for multiple food web levels. We used sequential bulk-tissue and compound-specific stable isotope analysis of carbon and nitrogen along the whiskers of an Antarctic apex predator, the Weddell seal (Leptonychotes weddellii), to assess its foraging habits in the two sites. The EAP δ¹³C values of bulk-tissue, essential, and non-essential amino acids (AAs) were on average 4.1 ‰, 4.8 ‰, and 6.4 ‰ higher than the WAP, respectively. This difference is caused by baseline differences and/or the use of prey supported by primary producers with distinctly heavier δ¹³C. The carbon values measured in EAP seals are unusual and contrast from patterns expected for Southern Ocean predators based on available isoscapes, which might be due to the influence of intense foraging near the bottom, and sea ice on pCO₂aq and carbon fractionation by primary producers. The δ¹⁵N values in bulk-tissue and AAs, on the other hand, indicated that seals are foraging in similar baselines and occupy equivalent trophic positions (TP_Pro-Phe= 3.3 ± 0.2, range = 2.7 - 4.3). However, differences in diet such as prey proportions are suggested based on differences between trophic AAs. Temporal patterns were also evident, as WAP seals showed a significant decrease in δ¹³C between 2014-2022, which is also likely related to ongoing warming along the WAP. The occupation of similar trophic positions between the WAP and EAP suggests that environmental shifts have not significantly affected the species’ trophic role, as they likely adapt their diets to different prey while maintaining their status as top predators in the Antarctic ecosystem. This result also highlights that Weddell seals are arguably less susceptible to food web disturbances compared to krill-feeding seals.

92

Using ICESat-2 Elevation Profiles and Viscoelastic Modeling to Constrain Ice-Shelf Rheology and Calving Potential

Emily Glazer^1,2, Dr. W. Roger Buck^1,2

¹Columbia University, New York, NY, USA. ²Lamont-Doherty Earth Observatory, Palisades, NY, USA

Abstract

Antarctic ice shelves lose approximately half of their mass to calving, and though mechanisms of calving are uncertain, it is highly likely that bending-induced stresses contribute. Standard models predict that ice shelves should bend downward at the front, but NASA ICESat(-2) data reveal upward bending profiles at many ice-shelf fronts. Upward flexure is dually dangerous for ice-shelf stability because it induces stresses at the base of the ice, which can lead to calving, and creates topographic depressions, which can lead to surface meltwater accumulation and hydrofracture. This upward flexure is widely attributed to ice-front melting near the waterline, which leads to a submerged ice bench and consequent additional buoyant force at the front. However, we have shown that vertical variations in ice viscosity can lead to upward flexure, even in the absence of a bench for ice shelves with cold surface temperatures. Variations in viscosity are expected because ice flow is temperature dependent.

Model results have shown that the bending moment mechanism produces profiles with smaller flexural wavelengths and greater depression depths than the bench mechanism. By comparing the geometries of ICESat-2 and modeled profiles, we aim to quantify the impacts of these two mechanisms along the Antarctic coast, thus helping us quantify stresses at each ice-shelf base that can lead to calving.

Furthermore, the internal moment model provides realistic flexure amplitudes for a limited range of viscosity parameter values (i.e. activation energy, fluidity, and the flow-law exponent). We systematically change these parameters in our flexure model, and compare the shape and rate of deformation of the modeled profiles with ICESat-2 profiles, in order to constrain values of these parameters, thus providing insights into how viscosity varies with depth near ice-shelf fronts. These parameters are known to vary in observations and lab experiments and greatly influence ice-mass-loss projections.

97

Antarctic red algae in photoelectrochemical cells for water splitting

Dra. María Fernanda Cerdá

Facultad de Ciencias, Montevideo, Uruguay

Abstract

Phycoerythrin (phycoE) extracted from Antarctic red seaweeds shows promising characteristics to be applied as sensitizers in water-splitting photoelectrochemical cells. Under light irradiation, the red-coloured protein shows an interesting ability to profit from the incident light, as confirmed by oxygen bubbles observed next to the electrode without applying any external potential. Thermodynamics analysis of the involved semi-reactions helps in understanding the results.

The cell contains two relevant electrodes: the FTO/TiO2/phycoE photoanode, where the red protein plays the leading role and where oxygen evolution takes place, and a platinum electrode, where hydrogen is formed.

Some reactions explain the overall process. On one side, after the light reaches the electrode surface, the dye (phycoE) transfers electrons to the FTO/TiO2 electrode. The solvent offers the opportunity: water produces oxygen and electrons, and the initial form of the dye is generated.

Considering the reported or measured redox potentials for the involved half-reactions, the titanium dioxide can receive these electrons, and phycoerythrin becomes the Dye+ species because the total potential is positive. Therefore, the ΔGtotal will be negative; consequently, the reaction could occur.

What happens next? The Dye+ is reduced and regenerated to its initial form; oxygen evolution from the water occurs. This process was detected by bubbles next to the electrode under the incidence of visible light. In this case, the global process shows a negative ΔG and takes place.

Summarizing, exploring Antarctic resources offers an alternative for developing green energies, with a particular focus on their use as sensitizers to profit from the sunlight in water-splitting and photovoltaic devices.

Acknowledgements

M.F.C. is an ANII and PEDECIBA researcher. Special thanks to the Instituto Antártico Uruguayo (IAU).

99

The Life cycle and variability of Antarctic weak polar vortex events

Dr. Lin Wang

Institute of Atmospheric Sciences, Chinese Academy of Sciences, Beijing, China

Abstract

Motivated by the strong Antarctic sudden stratospheric warming (SSW) in 2019, a survey on the similar Antarctic weak polar vortex events (WPVs) is presented, including their life cycle, dynamics, seasonality, and climatic impacts. The Antarctic WPVs have a frequency of about four events per decade, with the 2002 event being the only major SSW. They show a similar life cycle to the SSWs in the Northern Hemisphere but have a longer duration. They are primarily driven by enhanced upward-propagating wavenumber 1 in the presence of a preconditioned polar stratosphere (i.e., a weaker and more contracted Antarctic stratospheric polar vortex). Antarctic WPVs occur mainly in the austral spring. Their early occurrence is preceded by an easterly anomaly in the middle and upper equatorial stratosphere in addition to the preconditioned polar stratosphere. The Antarctic WPVs increase the ozone concentration in the polar region and are associated with an advanced seasonal transition of the stratospheric polar vortex by about one week. Their frequency doubles after 2000 and is closely related to the advanced Antarctic stratospheric final warming in recent decades. The WPV-resultant negative phase of the southern annular mode descends to the troposphere and persists for about three months, leading to persistent hemispheric-scale temperature and precipitation anomalies.

101

Tracking suspended particulate organic matter composition and diagenesis from Antarctic glacier runoff to coastal waters by amino acids

Prof. Dr. Natalia Venturini¹, Lic. Claudia Parodi¹, Ing. Luis Cerpa², Prof. PhD. Zhuoyi Zhu³, Prof. PhD. Jing Zhang⁴, Prof. Dr. Pablo Muniz¹

¹Oceanografía y Ecología Marina (OEM), Instituto de Ecología y Ciencias Ambientales (IECA), Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Instituto Geológico, Minero y Metalúrgico (INGEMMET), Lima, Peru. ³School of Oceanography, Shanghai Jiao Tong University, Shanghai, China. ⁴State Key Laboratory of Estuarine and Coastal Research (SKLEC), East China Normal University, Shanghai, China

Abstract

Increased glacier melting runoff in Antarctica involves intensification of freshwater, nutrients, sediments and organic matter inputs from land to the sea, which is impacting Antarctic fjords ecosystems and may alter their climate regulation service as organic carbon sinks. We used AAs as molecular tools to discern suspended particulate organic matter (SPOM) sources and degradation state, in two distinct environments, the proglacial melting runoff system of Collins Glacier (PROGLARS) and marine surface waters of Collins Bay. A total of 18 water samples were taken in January 2018 and filtered through GF/F membranes to concentrate SPOM. Marine sampling was performed onboard the R/V BAP Carrasco during the ANTAR XXV Peruvian expedition, while meltwater sampling was performed on foot, given the proximity to Artigas Station. SPOM in marine waters showed significantly higher AAs concentrations than in the PROGLARS. The proportion of nonessential amino acids (NEAAs) in suspended POM was higher than of essential amino acids (EAAs). NEAAs presented significantly higher molar % in marine than in PROGLARS SPOM, but the opposite was observed for EAAs. The ratio between D and L isomers was < 1. The degradation index (DI) varied between -0.12 and 0.78. Ser + Thr + Gly /Asp ratio presented significantly higher values in marine than in the PROGLARS SPOM, while Asp/Glu ratios showed the opposite trend. Hierarchical Clustering Analysis revealed that PROGLARS stations and marine stations form two distinct groups in terms of water physicochemical characteristics and SPOM AAs composition. Our results evidenced low concentrations of terrestrial SPOM in marine waters of Collins Bay attributed to low meltwater inputs. Less degraded SPOM was present in marine waters than in glacier melting waters. Further knowledge about meltwater runoff and SPOM dynamics in Antarctic coastal ecosystems, is critical, particularly in areas prone to undergo increased glacier melting in the following decades.

103

Large-scale atmospheric circulation information is stored by stable water isotopes from upper reaches of the Weddell Sea sector, West Antarctic Ice Sheet

MSc Andressa Marcher^1,2,3, PhD Jefferson Simões^1,4,3, MSc Ronaldo Bernardo^1,2,3, PhD Pedro Valente^1,3, PhD Francisco Aquino^1,3, MSc Isaías Thoen^1,3, PhD Filipe Lindau^1,3, PhD Luciano Marquetto^1,3,5, PhD Venisse Schossler^1,3

¹Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Programa de Pós Graduação em Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ³Instituto Nacional de Ciência e Tecnologia da Criosfera, Porto Alegre, Brazil. ⁴University of Maine, Orono, USA. ⁵Instituto de Geociências, Universidade Federal de Santa Maria, Santa Maria, Brazil

Abstract

Stable water isotopes data from ice/firn cores offer valuable insights into climate. They are the key to reconstructing Antarctica climate variability which is essential for understanding long-term connections between the southern polar region and the tropics. This study evaluated whether the isotopic time series from an upstream area of the Weddell Sea Sector (WSS), West Antarctica, captures local and regional climate conditions, as well as large-scale atmospheric circulation variability. Therefore, we examined the relationship between annually resolved data of water isotopic ratios (δs) from one shallow firn core (⁓9.0 m deep), meteorological data, and climate indices. We found that the positive δs anomalies are linked with (1) the warming of the Antarctic Peninsula (AP), southern tip of South America (SA) and high latitudes of the western Southern Atlantic Ocean; (2) the heat and moisture northerly flow by AP and WSS; (3) set up of positive geopotential anomalies on the southeast of SA and New Zealand and negative geopotential anomalies on the Amundsen Sea Low region; and to a lesser extent with (4) sea ice decreasing in the north of AP. These relationships reflect the influence of the large-scale climate modes onto the West Antarctica climate. Indeed, the interannual variability of the δs in the period 1999-2014 is strongly explained by changes in the phase SAM and PSA, with SAM+ and PSA1- phases related to positive δs anomalies in the upper reaches of the WSS (δ¹⁸O/SAM: r = 0.74, p < 0.05; δ¹⁸O/PSA1: r = -0.54, p < 0.05).

104

Antioxidant and emulsification activity of exopolysaccharide produced by a thermophilic Antarctic bacteria isolated from Fumarole Bay, Deception Island.

Ms. Catherine Ormeño¹, Dr. Aparna Banerjee²

¹Escuela de Ingeniería en Biotecnología, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule., Talca, Chile. ²Instituto de Ciencias Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Talca, Chile

Abstract

Exopolysaccharides (EPS) are high molecular weight carbohydrates that constitute extracellular carbohydrates surrounding the microbial cells under extreme environment. They often produce these bioactive compounds as part of their survival strategy against adverse environmental conditions, being a compound of great biotechnological interest and high value in pharmaceutical, cosmetic, water treatment and food industries. Compared to the production of synthetic polysaccharides, it is a great alternative to take advantage of the biological capacity of extremophiles where they synthesize and secrete polysaccharides as part of their normal metabolism. In the present study, the characterization of EPS produced by a thermophilic bacteria F2LB isolated from Fumarole Bay located on the Antarctic Peninsula, Deception Island, is elucidated. The formation of biofilm was analyzed through confocal microscopy, from 8 hours - 6 days for the quantification of EPS formation. The antioxidant activity of EPS is determined through the capacity to eliminate free radicals of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide, its chelating capacity of ferrous metal ions (Ferrozine) and finally the FRAP (Ferric Reducing Antioxidant Power) test at concentrations 0.2 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg, 5 mg of EPS. To determine their emulsifying activity, a total of 8 commercial food-grade oils (olive oil, corn oil, canola oil, vegetable oil, sunflower oil, sesame oil, rice oil and grape seed oil) at 1 mg EPS concentration is used. The results showed ~99% antioxidant activity against hydroxyl radical at all EPS concentrations, while the emulsifying activity showed best of ~85% against olive oil. It is concluded that the EPS produced by the Antarctic thermophilic isolate F2LB has great antioxidant capacity against and oil emulsification, being a great alternative for its use as biological antioxidants for food industries and taking advantage of its emulsification to improve the texture and consistency of foods.

Acknowledgment: INACH RT_24-21

108

Spatial variability and composition of surface mesozooplankton in the Bransfield and Gerlache Straits, Western Antarctic Peninsula.

Ms Camila Leonor

Universidade Federal do Rio Grande - FURG, Rio Grande, Brazil

Abstract

Zooplankton plays a pivotal role in the Southern Ocean (SO), exhibiting high sensitivity to environmental changes in the water column and being closely associated with oceanographic conditions. Water temperature is a crucial factor influencing their life cycles and composition. The Western Antarctic Peninsula (WAP) stands out as a climatic hotspot of immense scientific importance, being influenced by different water masses that characterize its biogeographic areas. In this context, this study aims to characterize interannual species variations in surface mesozooplankton communities in the WAP. We hypothesize that the distribution of zooplankton in the surface layer is linked to abiotic variables, primarily temperature. Data collection was conducted using a Continuous Plankton Recorder (CPR) during the austral summer of 2016 and 2017. The CPR is recognized for its extensive spatial capabilities. The region was divided into four sites along the Gerlache (GS) and Bransfield (BS) Straits. Daytime sampling occurred in GS and predominantly nighttime sampling in BS. PERMANOVA revealed significant differences in the community between years and sites. Copepoda and Salpidae were the most abundant groups (36% each in 2016 and 2017). Within Copepoda, Metriidia group dominated (85%). Naupliar stages and copepodites were more prevalent in BS during 2017. Appendicularia (10%) and Chaetognatha (9%) were prominent in both routes, with BS exhibiting higher abundances and specific composition. Results suggests that communities are influenced by abiotic characteristics that varied significantly between the two austral summers studied. Canonical Correspondance Analysis linked the most abundant composition to environmental variables, providing data explanation. Temperature positively influenced Metriidia and negatively influenced Salpidae. Both years marked distinct abiotic characteristics influenced by oceanographic and climatic events. This work contributes to the development of a global biodiversity database, sampling those straits for the first time with a CPR for two consecutive years.

111

Viability of Gray Level Co-occurrence Matrix textural analysis for temporal mapping of sea ice in Sentinel-1A SAR images

Dr. Fernando Luis Hillebrand¹, Dr. Juan Doblas Prieto², Dr. Cláudio Wilson Mendes Júnior³, Dr. Jefferson Cardia Simões³, Dr. Jorge Arigony-Neto⁴

¹Instituto Federal de Educacão, Ciência e Tecnologia do Rio Grande do Sul, Rolante, Brazil. ²Instituto Nacional de Pesquisas Espaciais, São José dos Campos, Brazil. ³Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁴Universidade Federal do Rio Grande, Rio Grande, Brazil

Abstract

Sea ice is one of the main components of the cryosphere, which plays a role in the exchange of heat and moisture between the ocean and the atmosphere, regulating the global climate. With climate change, it is necessary to monitor in detail the changes that occur over time in the sea ice concentration. In view of this, an analysis was carried out to identify the viability of Gray Level Co-occurrence Matrix (GLCM) textural analysis at different gray levels (4, 8, 16, 32, and 64) in SAR images from Sentinel-1A, HH polarization, Interferometric Mode (IW) imaging mode, in mapping the sea ice concentration (young ice and/or first-year ice) for time series in the Antarctic Specially Managed Area 7 (ASMA 7) oceanic region, located in the western region of the Antarctic Peninsula. Data processing was carried out using cloud computing on the Google Earth Engine platform. Programming was developed in JavaScript language that used samples from regions with open water and sea ice obtained in false-color SAR images (R-HH, G-HV, B-HV/HH) from Sentinel-1B to train the Random Forest classifier, Extra-Wide Swath (EW) imaging mode. The analysis consisted of creating difference maps of sea ice concentration that allowed checking whether training samples used in the classifier on a given date could be used for other periods, limited to freezing months. We verified in all analyses that the best quantization configuration for GLCM is 64 gray levels, and in the first analysis carried out in 2019, we found precision of 88% in the classification indicators and in the second analysis carried out in 2020, precision of 90%.

112

Early history of the ocean opening between Antarctica and Australia

Miss Vanda Sergeeva¹, Dr. German Leitchenkov^1,2

¹VNIIOkeangeologia, St. Petersburg, Russian Federation. ²Saint Petersburg State University, St. Petersburg, Russian Federation

Abstract

Until 80 Ma Australia and Antarctica were a single continent. Its break-up was driven by to synchronous processes – the propagation of spreading axes from the Indian and Pacific Oceans towards each other, with the orthogonal intersection of ancient lithospheric blocks. Reconstruction of the Australia-Antarctica break-up was carried out using GPlates software to study the geometry and formation of the South Indian Ocean Ridge (SEIR) in its early stage. In constructing the models, we relied on the position of magnetic anomalies for the Australian and Antarctic plates. The proposed reconstructions of Australia and Antarctica are based on the coincidence of conjugate magnetic anomalies of the same age, whose geometry has not changed since their formation. The early stage of the oceanic opening 80 – 40 Ma) is clearly divided into ultraslow (80 - 50 Ma) and slow (50 - 40 Ma) regimes. According to our models obtained, there is a distinct correlation between the change in spreading rates and the position of the poles of rotation. Between 80 and 50 Ma the pole of rotation was located in the west, in the area of the Kerguelen Plateau and Australia was moving westward relative to Antarctica. About 50 Ma, the rate of sea-floor spreading almost doubled (from ultraslow to slow) and Australia migrated to the north. The pole of rotation was located near the southern edge of Tasmania and continued to move southeast towards the Pacific Ocean.

113

Harnessing the power of policy co-design methodologies for efficient science communication to communities and policymakers: Assessing the effect of World Cafes

Dimitris Symeonidis

Decentralized Solutions Global Network, Thessaloniki, Greece

Abstract

Communicating science to policymakers and citizens can prove to be a troublesome task. Barriers can create issues, such as the inherent challenges of ambiguous or uncertain conclusions, but also the lack of familiarity of the audience or the way that scientists approach the audience, which is not consistent with the audience's profile and ambitions. The Antarctic is no exception to this rule. Decision-makers within the Antarctic Treaty System have to grapple between understanding the main and most important points of scientific research and using them to inform policymaking, so that it can, on one hand, mitigate the adverse effects of climate change in the Antarctic, while ensuring balance among the needs of all stakeholders. In order to achieve that, community engagement for policymaking co-design has been found to maximize social acceptance, while giving the opportunity to scientists to convey their results in an informal manner, making their own science accessible and putting it within the context of policymakers. An efficient community engagement way that have been implemented successfully are the implementation of World Cafe workshops. The World Cafe methodology is a method that is best used for: gathering collective intelligence on experiences or ideas around an issue and generating new ideas. This paper will showcase how world cafe was used during the EU Sustainable Energy Week, the EU Youth Week and the Arctic Plastics Symposium in three cases: The energy transition, the Arctic Plastics Crisis and the Decarbonization of the heavy industry. This paper will discuss the main successful points and challenges that this methodology had with regards to policy recommendations generation and science acceptance both from the communities and the policymakers. Finally, this paper will present how this methodology can be used in the context of creating a policy to deal with maintaining the Antarctic biodiversity amidst climate change.

114

Seismic stratigraphy and Sediment Distribution in the area off Ellsworth Land, West Antarctica

Miss Vanda Sergeeva¹, Dr. German Leitchenkov^1,2, Mr. Vitaliy Kaulio³

¹VNIIOkeangeologia, St. Petersburg, Russian Federation. ²Saint Petersburg State University, St. Petersburg, Russian Federation. ³Polar Marine Geosurvey Expedition, St. Petersburg, Russian Federation

Abstract

Preliminary results of marine geophysical survey carried out on R/V “Akademik Alexander Karpinsky” during the 2023-2024 field season (69th Russian Antarctic Expedition) are presented. Data were collected in the Bellingshausen Sea off Ellsworth Land between 75E and 100E. A total of 1500 km of Multichannel seismic (MCS), gravity, magnetic and multibeam data were collected. The MCS observations were carried out using a 6000-m-long digital streamer and 2 lines of airguns with a total volume of 2200 cub.in. The sediments of the study area record the Late Cenozoic evolution of the West Antarctic Ice Sheet. Different seismic facies, formed by mass-wasting and current-controlled processes, have been identified. Analysis and interpretation of seismic data provide information on sediment input and sediment transport patterns and to infer past changes in climate and oceanography.

121

Cold-adapted aldehyde dehydrogenases from Antarctic bacteria for enhanced applications in biotechnologies and biosensing

Dr Cristina Purcarea¹, Dr Georgiana Necula-Petrareanu¹, Dr Victoria I Paun¹, Dr Catalina Sanda¹, Ms Roberta M Banciu², Ms Andreea Ftodiev², Dr Alina Vasilescu²

¹Institute of Biology Bucharest, Bucharest, Romania. ²International Centre of Biodynamics, Bucharest, Romania

Abstract

The most recent advancements in biotechnologies and biosensing are focused on cold-active extremozymes. In this context, we investigated the potential of two NAD(P)⁺-dependent aldehyde dehydrogenases (F-ALDH and S2-ALDH) derived from the Antarctic Flavobacterium sp. PL002 strain for efficient aldehydes catalysis at low temperatures.

The recombinant enzymes were obtained by cloning and expression in Escherichia coli BL21(DE3), and were purified in one step by Ni-NTA affinity chromatography. Structural and phylogenetic analyses indicated substantial protein similarities (89-95%) with psychrophilic homologs, including conserved active residues and structural elements that confer enzyme flexibility.

Both ALDHs revealed an unexpected high thermal stability, operating effectively in the 4-60ºC temperature range, and displayed a biphasic Arrhenius plot for the NAD(P)⁺-dependent reactions that indicated conformational changes at 30°C promoting catalysis at higher temperatures. F-ALDH utilized both cofactors with a preference for the NAD⁺-dependent reactions, and showed versatility in catalyzing a broad range of aliphatic and aromatic substrates, while S2-ALDH showed preference for the utilization of acetaldehyde. A distinct optimal pH of 9.5 and 7.5 was recorded for the F-ALDH and S2-ALDH, respectively, making the later one a valuable candidate for developing biosensors. Both enzymes were stable in the presence of various ions and additives, while S2-ALDH was characterized by sensitivity to mercury (I₅₀ = 1.21 μM) and high tolerance to ethanol (15%), making it advantageous for wine analysis.

F-ALDH was immobilized on carbon nanoparticles, showing high catalytic efficiency at 15°C for aliphatic aldehydes and stability to lyophilization. Meanwhile, an enzymatic electrochemical assay was developed for the detection of acetaldehyde in wines based on S2-ALDH with demonstrated accuracy as compared to the reference spectrophotometric method. These characteristics underscore the potential of the Antarctic ALDHs as promising biocatalysts for industrial and biosensing applications related to NAD(P)⁺ oxidoreductase reactions and aldehydes monitoring.

122

Sources and distribution of biogenic sterols in surface sediments from Admiralty Bay, King George Island, Antarctica.

B.Sc Gabrielle Lube, Ph.D César Martins, Ph.D Satie Taniguchi, Ph.D Rafael Lourenço

University of São Paulo, São Paulo, Brazil

Abstract

The Antarctic continent is one of the most protected areas on the planet, but is dynamically responding to environmental change on a global scale. Some clues of how Antarctica has responded to these changes can be obtained from studies involving the organic matter (OM) geochemical cycles, where cycling is primarily driven by autotrophic biogenic processes, with minimal anthropogenic interference. In this context, the identification of environmental changes on different time scales can be achieved through the application of geochemical organic markers, like sterols. These biomarkers serve as indicators due to their resistance to degradation and ability to retain details of their original source. Then, this study aims to examine the space-time distribution of sterols to understand origin, input variability, preservation, and degradation of the OM in surface sediment from Admiralty Bay, King George Island. Sampling was carried out during the austral summers of 2019/2020 and 2022/2023 along the Martel, Mackelar, and Ezcurra inlets. Sterols were analysed using gas chromatography with a flame ionization detector after Soxhlet extraction, liquid adsorption column purification, and derivatization reaction. The results suggest that in this environment there is a multiplicity of marine sources as phyto- and zooplankton, penguins and seals feces. Furthermore, the differences in concentration and sources among the inlets likely reflect variations in the abundance of organisms associated with these sterols. This finding highlights their heterogeneous distribution in the environment. The relevance of this study lies in the fact that the data obtained allow for a more accurate assessment of the variability of autochthonous sources of sedimentary OM. Moreover, understanding the environmental dynamics influencing changes in Antarctic sedimentary OM will enhance our knowledge of global biogeochemical cycles, given the region's crucial role in the global climate system.

123

Advancing under-ice hyperspectral imaging of shallow Antarctic coastal marine habitats with HICYBOT

Dr Emiliano Cimoli¹, Dr Juan Carlos Montes-Herrera¹, Associate Professor Vanessa Lucieer¹, Peter Marriott², Dr Leigh Tait², Dr Vonda Cummings²

¹University of Tasmania, Hobart, Australia. ²NIWA, Wellington, New Zealand

Abstract

Antarctic coastal benthic biodiversity is intricately linked to the dynamic nature of sea-ice biophysical properties, exhibiting significant spatial and temporal variations. Predicted changes in seasonal sea-ice dynamics highlight the need to assess our current capacity to monitor how shallow ice-covered marine habitats will respond to shifts in sea ice dynamics, and oceanographic processes, across multiple spatio-temporal scales

Underwater hyperspectral imaging (UHI) holds promise as a non-invasive approach to revolutionize monitoring of under-ice environments. However, current limitations in underwater navigation and image georectification compared to terrestrial counterparts persist. Moreover, UHI spectral algorithms require careful evaluation and customization for each study context

We present preliminary data products from an acoustically aided under-ice Remotely Operated Vehicle (ROV), 'HICYBOT,' designed to conduct benthic and sympagic surveys using stereovision-coupled UHI in Antarctic coastal environments. Operating at high spatial (5 cm) and spectral (<3.4 nm) resolutions, HICYBOT integrates an Ultra-Short Baseline (USBL) positioning system for precise mapping and georectification of pushbroom UHI via fully integrated GNSS positioning and inertial navigation systems

Our initial mission deployed HICYBOT in the shallow regions of the Ross Sea, part of the world's largest marine protected area renowned for its pristine ecosystem and biodiversity. We had three primary objectives, to: A) produce georeferenced hyperspectral strips of the seafloor and overlying sea-ice, B) evaluate both supervised and unsupervised spectral classification algorithms for seafloor characterization, and C) quantify microalgae biomass beneath the overlying ice cover. By achieving automated classification of the major benthic features (up to 5) and being able to quantitatively estimate ice algal biomass of the overlying ice cover (as Chl-a in mg m⁻²), the system represents a significant advancement in under-ice monitoring technologies, with potential to elucidate the intricate cryo-benthic interconnections and their response to evolving sea-ice dynamics.

125

Microplastic pollution of soils and freshwater in Vecherny Oasis, Thala Hills, Enderby Land

Prof. Tamara Kukharchyk, Prof. Sergey Kakareka, Kiryl Rabychyn

Institute for Nature Management of the National Academy of Sciences of Belarus, Minsk, Belarus

Abstract

To date, the presence of microplastic particles in various natural components (in the surface layer of snow, glacier, sea ice, seawater, bottom marine sediments, surface freshwater and in soil) in different Antarctic regions has been confirmed. But East Antarctica remains poorly investigated on this issue.

The purpose of our study is to obtain the first estimates of the content of microplastic particles (less than 5 mm) in the soils and freshwater bodies of the Vecherny Oasis, Enderby Land for understanding of this type of environmental pollution.

The samples of soil and freshwater taken during 14th (2021/2022) and 15th (2022/2023) Belarusian Antarctic Expeditions were analysed. Seven samples of soils from a depth of 0-15 cm were separated into two fractions (less than 1 mm and 1-5 mm) and studied in 3 replicates. The technique for isolating microplastic particles from soil included density separation in zinc chloride solution, centrifugation, vacuum filtration through glass fiber filters with pore diameter of 1.6 μm. The freshwater from three lakes and one temporary reservoir was filtered in the field conditions through a plankton network to concentrate the sample, which were filtered at once in the laboratory through White Ribbon filters. Quantification of microplastic particles was carried out using a microscope, digital camera and advisory software. It was found that microplastic particles present in all analyzed samples. Particles <1 mm in size are predominated both in soil and water. Fibers, fragments and films were found and their possible sources are discussed. It is shown, that further research is needed in order to identify the accumulation of microplastics depending on the terrestrial and aquatic system properties and geochemical processes in cold climate.

127

How the Antarctic region is (or isn't) presented in Natural Sciences and Geography textbooks in elementary education in Brazil

B.Sc.B Beatriz Andrade, PhD Silvia Dotta, PhD Sandra Affonso

Federal University of ABC, Santo André, Brazil

Abstract

This article aims to analyze how Antarctica and polar regions are presented in the textbooks adopted by Brazilian schools. The introduction of Antarctic sciences into the school curriculum can contribute to understanding topics such as climate change, biodiversity, and the fundamentals of life and Earth. In Brazil, Antarctic studies are limited to 8th-grade curriculum. However, it is understood that schools can teach "through" polar regions, addressing concepts brought from the science practiced there. In this study, six collections of Geography textbooks (1G, 2G, 3G) and Natural Sciences textbooks (1C, 2C, 3C) were selected, as indicated by the National Book and Didactic Material Program of the Ministry of Education of Brazil, for adoption by public schools in Basic Education (6th to 9th grade). A search was conducted for the strings 'Antarctica,' ‘Antártida’,' 'Polar Regions’, in 24 works, 12 of Natural Sciences and 12 of Geography.

A higher frequency of the strings was identified in Geography works than in Sciences, with 933 occurrences in Geography and 102 in Sciences. In Geography, works 2G and 3G had 296 and 337 occurrences, respectively, while work 1G had 300. This may indicate that the first two works paid more attention to the national curriculum. In Sciences, the frequency is as follows: 1C = 32, 2C = 29, and 3C = 41, demonstrating that although these themes are not mandatory in the national curriculum, they are beginning to emerge in the conceptual horizon of schools.

In future work, the addressed subthemes will be analyzed to infer the depth and breadth of Antarctica in school content, provide support for the development of lesson plans that consider teaching science topics through Antarctica, and broaden the debate on the need to address polar sciences throughout the school curriculum.

Keywords: polar regions, Antarctica, Antarctic, school curriculum, textbook

128

An evidence of aerial transport of diatom during a volcanic eruption in Deception Island, Antarctica

Ms. Anna Beatriz Oaquim^1,2, Prof. Dr. Heitor Evangelista², Prof. Dr. Marcus Vinícius Licínio³, Prof. Dra. Gleyci A.O. Moser⁴, Dra. Domênica T. Lima⁵

¹Faculty of Geology, PPGG,Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ²LARAMG, Institute of Biology Roberto Alcantara Gomes, Rio de Janeiro State University, Rio de Janeiro, Brazil. ³Department of Physiological Sciences, Espírito Santo Federal University, Espírito Santo, Brazil. ⁴LABCULT, Faculty of Oceanography, Rio de Janeiro State University, Rio de janeiro, Brazil. ⁵LABCULT, Faculty of Oceanography, Rio de Janeiro State University, Rio de Janeiro, Brazil

Abstract

A sediment corer, measuring 0.5 meters in length, was extracted from the proglacial lake, Profound Lake, located on the Fields Peninsula of King George Island (KGI), during the summer of 2013. The acquired sediment core underwent precise dating utilizing Pb-210, unveiling that the uppermost 0.23 meters pertained to the temporal span from 2013 to 1800. To systematically assess alterations in diatom diversity and relative abundance over chronological epochs, the corer underwent subsampling at 1-centimeter intervals. Each subsample are analyzed using light microscopy (LM) observation and scanning electron microscopy (SEM). The taxonomic scrutiny identified a total of 13 diatom species, predominantly comprising pennate and freshwater taxa, endemic to the Maritime Antarctic region, and previously documented on KGI. An exception to this pattern was the identification of Luticola gigamuticopsis (Van de Vijver, 2008), a pennate and freshwater diatom species typically found in streams and seepage areas across Deception, James Ross, and Livingston Islands. Remarkably, this species was first described for KGI in the 15-centimeter layer of our Profound lake sediment core, corresponding to the year 1970. Two hypotheses were postulated to elucidate this finding: firstly, it may signify the inaugural documentation of the species on the island; secondly, the species discovered could be linked to the substantial volcanic eruption on Deception Island in 1970. In accordance with the model proposed by Pedrazzi et al. (2014), particles on the order of 1μm during the Deception eruption could have reached KGI owing to atmospheric circulation. Given the diminutive size (<1μm) and lightweight nature of the identified specimen, back trajectories were conducted using HYSPLIT to investigate whether wind patterns during the eruption could have transported diatom valves to KGI. The trajectories, particularly during the eruption day and in proximity to its commencement, revealed potential paths from Deception Island to KGI, thereby corroborating our hypothesis.

130

Preliminary results on the foraging behavior of Adélie and gentoo penguins breeding at Stranger Point/Cabo Funes (25 de Mayo/King George Island, South Shetland Islands) during the 2017/2018 season

Dr. Mariana A. Juáres^1,2,3, PhD Student Antonella Farace Rey^1,2,4, PhD Student Claudio Matko⁵, Dr. Ricardo Casaux⁶, Dr. M. Mercedes Santos^1,3

¹Instituto Antártico Argentino (IAA), San Martín, Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina. ³Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina. ⁴Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina. ⁵Instituto de Ciencias de la Tierra, Universidad Estatal de San Petersburgo, San Petersburgo, Russian Federation. ⁶Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET–UNPSJB), Esquel, Chubut, Argentina

Abstract

Knowledge of the foraging behavior of bioindicator species, such as penguins, allows us to understand the ecosystem functioning, assess the effects of environmental variability on the ecosystem, and identify the priority areas for their conservation. At Stranger Point/Cabo Funes, Antarctic krill (Euphausia superba) dominates the diet of chick-provisioning Adélie (Pygoscelis adeliae) and gentoo (P. papua) penguins. The foraging behavior of these species at this site had not been previously analyzed using GPS loggers. Thus, at Stranger Point we studied the horizontal movement of these species guarding chicks during 2017/2018, generating a baseline for long-term studies on movement patterns. Adélie penguins reached a maximum distance of 20.78 km from the colony and a total distance traveled of 56.82 km (n = 9 birds, 19 trips). Furthermore, the maximum time this species spent at sea was ~17 hours. Instead, gentoo penguins foraged a maximum of ~14:40 hours, reaching a maximum distance of 28.59 km and a total distance of 59.62 km (n = 9 birds, 15 trips). These parameters did not differ between species (LMM or GLMM, p > 0.05). However, differences were observed in the time of day when trips began (LMM, p = 0.01), with gentoo penguins traveling earlier in the morning (Post hoc Tukey test, p = 0.02). All individuals moved mainly towards the southeast of the colony. Our preliminary results show that both species exploited similar feeding areas during 2017/2018, without an apparent reduction in the breeding success (1.40 ± 0.72 and 1.46 ± 0.76 chicks in crèches for Adélie and gentoo, respectively). These would suggest that prey was not a limited resource during the study period, and the breeders of both species concentrated their efforts in coastal waters, which provided productive foraging grounds. These findings highlight the importance of conserving the coastal habitats close to the colony.

132

Mapping Southern Ocean Blue Carbon

Mr Duncan Sinclair, Miss Theresa Gossmann, Mr David Barnes

British Antarctic Survey, Cambridge, United Kingdom

Abstract

The Southern Ocean is one of the few locations in the world currently demonstrating capabilities as a net carbon sink in the face of a changing climate. Understanding the current extent of carbon stored in the waters surrounding Antarctica will provide a baseline for a range of future research areas into Antarctic blue carbon.

In essence, this project aims to pull together all current knowledge of carbon held within marine sediments in the Southern Ocean. This exercise will assist in identifying hotspots and coldspots of blue carbon, as well as outlining gaps in the spatial distribution of data collection. It is anticipated that the findings of this research will assist in pinpointing areas where blue carbon does (or does not) overlap with conservation efforts (e.g., MPA’s), and will present an opportunity to give policy advice on meaningful ecosystem protection.

Expanses of benthic data relating to carbon storage exist for the Southern Ocean, yet no cohesive effort has been made to collate the information into a standardised workable format. An opportunity exists to create a large-scale GIS database with continual input from previous and ongoing research regarding blue carbon stocks in the Southern Ocean. This database will serve as a visualisation of blue carbon in the Southern Ocean, translating decades of research into a format which allows for effective understanding and analysis.

133

How to motivate schools to work in Antarctica: the case of EB Abadias in Figueira da Foz, Portugal

Teacher Paula Maricato¹, Silvia Dotta²

¹EB Abadias - Agrupamento de Escolas da Zona Urbana da Figueira da Foz, Figueira da Foz, Portugal. ²Federal University of ABC, Santo André, Brazil

Abstract

Noting that the 1st cycle curriculum does not include the topic of Antarctica and having become aware of a Portuguese scientific contingent whose object of study is Antarctica, through the newspaper “Diário de Coimbra”, this led us to introduce Antarctica into the curriculum . Our school, EB Abadias, a 1st cycle school with thirteen classes, belonging to the Figueira da Foz Urban Zone School Group, located in the city of Figueira da Foz (40 km from Coimbra) whose teachers have embraced the Antarctica theme in their pedagogical practices. Over the last 10 years, EB Abadias has been continuously developing Polar Education projects with two highlights “Polar Weeks” and the celebration of Antarctica Day (with a flag for Antarctica). What began by involving three 2nd year classes at the school in 2013/14 with the creation of a flag and the development of an eTwinning Project, “Antarctica - the Flag”, grew in motivation and interest from teachers and different groups of students. In addition to research, the development of eTwinning projects, some of them awarded with National and European Seal, recognition of the Leya Child Friendly School Seal, ended up becoming part of the school's dynamics in projects such as: Eco-Schools, Escola Azul and a solidarity writing project that culminates annually with the publication of the book “Ajudaris”. In conclusion, this work continues this year, with an interdisciplinary approach, which culminates in the execution of flags from eight classes, who arrived in Antarctica via: United Kingdom, Base Comandante Ferraz (Brazil) and also by a Portuguese scientist. The various research in the classroom on the geographical situation, the climate and the fauna motivated the students to create Penguin costumes for the school's Carnival Parade. Attendance a set of activities such as: lectures, classroom projects, constitute the main cause of EB Abadias' engagement in polar themes.

135

Development of Polar Exploration Robot and Field Test in Antarctica

Ph.D Ji-Wook Kwon, Mr. Hyoujun Lee, Ph.D Taeyoung Uhm, Ph.D Young-Ho Choi

Korea institute of Convergence & Technology Convergence, Pohang, Korea, Republic of

Abstract

This paper describes the development of polar exploration robot and the results of field tests in Antarctica. The Korea Antarctic Robotic EXplorer (KAREX) is designed to enhance the safety of researchers and support scientific research through long-distance autonomous navigation in the harsh Antarctic environment. Its primary missions include crevasse exploration with Ground Penetrating Radar (GPR) and towing of exploration equipment. To achieve sustainable and robust operations in the harsh Antarctic conditions, KAREX incorporates a suspension system within its four crawler units and a modular design for durability and adaptability in challenging Antarctic conditions. An advanced active temperature control unit that includes a self-insulating structure was applied to protect the internal electronic components. The autonomous driving software, built on a distributed architecture, supports real-time processing and autonomous decision-making, alongside a user-friendly remote control interface for operators without robotic expertise. Field tests in Antarctica validated KAREX's design against the continent's harsh conditions, demonstrating its robust performance and potential for contributing to polar research.

137

Multi-process Drilling in Complex Sub-glacial Geological Environments in Antarctica

Professor and Doctor Rusheng Wang, Doctor Guigang Tu, Professor Baochang Liu, Mr. Zhihao Cui

Jilin University, Changchun, China

Abstract

It is of great significance to study the geological structure of Antarctica, detect Antarctic mineral resources, reveal the evolution history of the ice sheet, and assess future climate change by quickly drilling through the Antarctic ice sheet and directly obtaining the cores or samples of subglacial bedrock, performing analysis of rock cosmogenic nuclides and mineralogy, and determining the age and structural composition of rocks. Due to extremely harsh climate and polar geographical features, like low-temperatures, remoteness, blizzards and low-level drifting snow, sea ice, glaciers, permafrost, magnify operational and logistic problems in Antarctica and require unique engineering approaches. Especially, the existing drilling technology in polar region cannot be applied to the complex subglacial geological environment of Antarctica. Until now a small number of subglacial bedrock cores have been obtained internationally so far, which cannot support the requirements of Antarctic scientific research. Thus, it is urgent to carry out study on drilling technology in the complex subglacial geological environment of Antarctica. This report firstly introduces the scientific significance and challenges of subglacial bedrock drilling in Antarctica, and analyzes the achievements and working characteristics of conventional polar drilling methods at the current stage, then it proposes multi-process drilling solutions to deal with the complex subglacial geological environment of Antarctica and overcomes the shortcomings of conventional drilling methods. At last, this report expounds the current research progress of multi-process drilling technology in the complex subglacial geological environment of Antarctica.

138

Geo-effectivity of the geomagnetic storms of June 22-23, 2015 in solar cycle 24.

Dr Inza GNANOU¹, Dr Salfo KABORE², Dr Karim GUIBULA², Pr Frédéric OUATTARA²

¹École Normale Supérieure (ENS), Koudougou, Burkina Faso. ²Université Norbert ZONGO, Koudougou, Burkina Faso

Abstract

Observations of solar events on the ground and in space reveal that geomagnetic storm can be seen as an event in which disturbances are triggered by solar flares. They occur when Sun's intense magnetic fields become too entangled. These powerful blasts of magnetic plasma, erupted by Sun, travel at millions of kilometers per hour through interplanetary space and interact with the Earth's magnetosphere. Solar and magnetic storms simultaneously affect vast regions of our planet, and equatorial ionospheric disturbances regularly occur around the world. Consequences on Earth are manifold (satellite communications affected, GPS lost, impact on human health, damage to power grids, etc.). Solar events play an important role in our understanding of solar wind/magnetosphere-ionosphere system. While it seems that magnetosphere and ionosphere interact crucially during strong storms, the nature of this interaction only addresses the ionized part (ionosphere) of the terrestrial environment. Objective of this manuscript is to assess the geo-effectivity of the second largest geomagnetic storm of June 22-23, 2015 (the first storm was St. Patrick's Day, March 17, 2015). We use interplanetary data from spacecraft (ACE,... ) at 1 AU and those from ground observations (http://www.bcmt.fr/data_download.php). Our results show that magnetic storms and energetic particles from powerful solar winds are two main consequences of CMEs that determine space weather on and near the Earth. Strength of a solar storm is controlled by Bz component of the CMI (IMF-Bz) and by solar wind/magnetosphere dynamo. During June 2015 storm, sudden north/south rotation of the IMF-Bz produced an electric convection field whose amplitude becomes very high for a meridional orientation of the IMF-Bz. Fortunately, the unsuspected June 2015 event only lasted around two hours and had only minor consequences on our planet. Hence the importance of predicting solar events, given mankind's growing dependence on space technologies.

139

Signals of volcanism from Sturge Island in West Antarctica ice cores

Dr Franciéle Schwanck, Dr Jefferson Cardia Simões, Andressa Feldkircher, Msc Ronaldo Bernardo, Dr Jeffrey Auger

Centro Polar e Climático, Porto Alegre, Brazil

Abstract

More than a hundred volcanoes have been identified in Antarctica, some of which are entirely buried beneath the ice sheet and others as submarine volcanoes. Satellite images from 12 June 2001 show a characteristic cloud over Sturge Island (67.4°S, 164.83°E), the southernmost island of the Balleny Islands archipelago, located off the coast of Victoria Land. The first analysis showed that the cloud reached up to 300 km in length in the downwind portions (E-NE) and reached 6 km in height. It showed signs of containing SO₂, but without the presence of identified ash, the image becomes inconclusive about whether or not it was produced by a volcanic eruption. Here we use the chemical analysis of a few ice cores (IC-04, IC-06, and Mount Johns) to interpret possible volcanism. These cores were collected in the western portion of the Antarctic ice sheet. The main analysis from the ice cores were trace elements (determined by Inductively Coupled Plasma Sector Field Mass Spectrometry - ICP-MS) and ionic content (analyzed by ion chromatography). The chemical analysis showed anomalous concentrations of S, Na, Ca, Ti, Cr, Mn, Fe, Co, and SO₄ for the period related to the eruption on Sturge Island. Air mass trajectories demonstrated some air parcels were transported over the West Antarctic ice sheet from the Balleny Islands to the ice core sites at the time of the potential eruption, establishing a route for transport and deposition of volcanic products over the ice sheet. This study seeks to improve the dating of ice cores by establishing a new horizon of absolute age and connections between records. It can also corroborate with other observations that had pointed to the Balleny Islands as a source of volcanic products.

140

A multi-matrix investigation of microplastics and marine litter pollution in Admiralty Bay, Antarctica

Gabriel De la Torre, Luis Santillán

Universidad San Ignacio de Loyola, Lima, Peru

Abstract

Marine litter is one of the most pressing environmental issues worldwide, associated with entanglement, entrapment, and its ingestion by many aquatic species. Plastic composes the vast majority of marine litter reported in coastal areas. Due to their long-lasting stability, plastics tend to break down into smaller pieces rather than naturally degrading, leading to the formation of microplastics (<5 mm). While marine litter and microplastics have been linked to anthropogenic activities and highly populated areas, the Antarctic environment is not free from these contaminants. In the present study, marine litter surveys were conducted along the coastline in the vicinity of the Machu Picchu Scientific Base, located on King George Island. Furthermore, microplastics were investigated in the surface waters and sediments of Admiralty Bay. The majority of the marine litter items found were composed of plastic, followed by metal structures. The majority of the items were recorded closer to the scientific base, most likely associated with the yearly Antarctic expeditions carried out during the austral summer. Pieces of paint, wood, and cardboard were also found. The analysis by Fourier transformed infrared spectroscopy (FTIR) indicated that the plastic items were composed of polystyrene (PS), low-density polyethylene (LDPE), and polypropylene (PP), among other polymers. Microplastic concentrations in surface waters and sediments ranged from 1.22 – 3.66 MPs/m³ and 0.00 – 0.30 MPs/g, respectively. In both cases, blue fibers were the most abundant microplastics. The analysis by micro-FTIR indicated the presence of cellulose, followed by polyester, PP, and alkyd resins. Most of the cellulose fibers were colored, potentially deriving from anthropogenic textiles. Other polymers may have been derived from synthetic plastic products and alkyd resins from marine coatings. This study confirms the influence of anthropogenic activities on the contamination of the Antarctic environment. However, their effects on the local ecosystems and conservation goals need further research.

145

The Brazilian Polar Film Festival as a proposal to disseminate knowledge about Antarctica and the Arctic and reach new audiences

PhD Sandra Freiberger-Affonso¹, PhD Sílvia Dotta¹, Nelson Barretta², PhD Norma Reggiani³, MSc Eduardo Akio Sato^4,3

¹Federal University of ABC, Santo André, Brazil. ²InterAntar, São Paulo, Brazil. ³Instituto Principia, São Paulo, Brazil. ⁴Estate University of Campinas, Campinas, Brazil

Abstract

The Brazilian Polar Film Festival (Mostra Brasileira de Filmes Polares) is an event created by the InterAntar program, aimed at scientific communication about the polar regions, through a transmedia system. In the various actions carried out by the program, it was observed that knowledge about Antarctica had not yet reached the general public, especially adults, which led us to propose a film screening open to the public, to provide an environment for disseminating the knowledge about the polar regions and open a space for discussions. With this objective, the first edition of the event was held at the Instituto Principia´s digital dome. Through audiovisual productions carried out by filmmakers, scientists and sailors, aspects of the importance of polar regions in the global context were disclosed, bringing together productions with different languages. The selected films formed an eclectic panorama involving science, environment, adventure, history, discoveries, rediscoveries and reflections. In total, nine productions were shown: seven Brazilian and two Uruguayan. The event was publicized on social media and on the project website and, to increase engagement with the public, live interviews were held with the films' creators, broadcast on YouTube. During the event, at least one representative from each film participated in a round of spontaneous questions with the audience after the film screening. To complement their knowledge about the polar regions, viewers received educational books and games, developed by InterAntar.

The event had an average of 75 people per session, the majority of whom were adults over 30 years old. This first edition of the event was an important strategy to begin reaching audiences that polar science rarely reaches in Brazil, contributing to the formation of a polar mentality. The experience of watching the films and talking personally to their creators increased interest in the theme.

147

Mountain climbing expeditions as a tool citizen science in the Antarctic inland areas

Dr Igor Sinitsyn¹, Dr Andrii Fedchuk²

¹Institute of Software Systems, Kyiv, Ukraine. ²National Antarctic Scientific Center, Kyiv, Ukraine

Abstract

Antarctic tourism has grown increasingly and diversified over the past three decades, becoming the major human activity in Antarctica in terms of number of tourists and transport units involved in this industry. Consequently, numerous locations experience a significantly higher number of tour visitors compared to field researchers. At the same time, scientific needs continue to emphasize the necessity of extending intra-Antarctic land routes and enhancing ground traversing capabilities, particularly in the exploration of understudied but scientifically interesting regions. In this regard, a citizen science collaboration with the International Association of Antarctica Tour Operators (IAATO) sea- and land-based expeditions provide important logistics capabilities for overcoming the challenges of extraordinary access to geographically isolated parts of the Southern Ocean and the continent and collecting the raw data to the scientific community. While numerous examples illustrate how citizen science programs onboard cruise ships successfully collect scientific data on marine environment and species identification, this paper presents the design of an initiative to invite deep inland tourist expeditions to collect observations data which could significantly supplement insufficient traditional field studies. The uniqueness of the Antarctic highlands, the increase in mountaineering in Antarctica, and the recent development of photo-video gadgets is an incentive to use this situation to initiate collecting the raw data based on media materials and special observations of participants in mountaineering in Antarctica. It is assumed that involving citizen science data from the mountain climbing expedition might also contribute significantly to multi-nationally coordinated research and long-term scientific monitoring to better understand the Antarctic environment as a unique and crucially important area for the Earth System.

148

Distributions of δ¹³C-DIC in the Austral Summer of 2023 along the Bransfield Strait, Antarctica.

Bsc Yasmym Schutz de Vincenzi Weirich¹, Dr Eunice da Costa Machado¹, Dr Luis C. Cotovicz J.², Dr Rodrigo Kerr¹

¹Federal University of Rio Grande, Rio Grande, Brazil. ²Leibniz Institute for Baltic Sea Research, Warnemünde, Germany

Abstract

The Southern Ocean plays a crucial role in climate regulation and the global carbon cycle, serving as a hotspot for environmental changes. This study aims to assess the carbon cycle and its interactions in the Bransfield Strait, North Antarctic Peninsula. An unprecedented approach in the region was taken in 2023 by utilizing the distribution of δ¹³C in dissolved inorganic carbon (δ¹³C-DIC). The Bransfield Strait is a highly dynamic region, where the physicochemical properties of seawater are primarily governed by two main water masses: the relatively old, warm (~1.5°C), and nutrient- and DIC- rich Circumpolar Deep Water (CDW), and the relatively young, cold (~ -1.8°C), and oxygen- rich Dense Shelf Water (DSW), recently formed over the Weddell Sea continental shelf. This study highlights that CDW (DSW) contributed to 60% (~10 to 40%) to the mixture in the deep layer of Bransfield Strait. This dominance is further emphasized by the positive South Annular Mode index during the analyzed period, facilitating increased CDW intrusions in the region. The isotopic signature exhibits variations in both vertical and horizontal distributions. Vertical distribution is primarily shaped by the biogeochemical processes, such as photosynthesis, which enriches surface water with the heavier isotope (ranging from 2 to 1.5‰), and degradation of organic matter, which deplete the heavier isotope in the water below the mixed layer (ranging from 0 to –2‰). The horizontal distribution of δ¹³C-DIC is determined by the water masses structure and advection processes in the region. CDW displays an isotopic signature of ~1 to 1.5‰, being more enriched in δ¹³C-DIC due to its status as an older water. In contrast, DSW is more depleted in, as observed in the central basin from Bransfield Strait (~-1 to -2‰). Therefore, δ¹³C-DIC serves as a valuable tracer for biogeochemical and hydrodynamic processes in the Bransfield Strait.

149

Antarctic airborne surveys: CECs and Chilean Navy collaboration, November 2023

Jose Uribe¹, Marisella Ortega¹, Jonathan Oberreuter², Alejandro Silva¹, Jonathan Garces¹, Barbara Rojas¹, Nicolas Garcia¹, Sebastian Cisternas¹, Claudio Bravo¹, Camilo Muñoz¹, Pablo Bunster¹, Cesar Delgado³, Claudio Bunster¹, Cristobal Rodriguez³, Rodrigo Zamora¹

¹Centro de Estudios Cientificos, Valdivia, Chile. ²Centro de Estudios Científicos, Valdivia, Chile. ³Armada de Chile, Valparaiso, Chile

Abstract

The Antarctic Peninsula has experienced a significant increase in temperatures in recent decades, surpassing the global average several times over. This warming trend has led to the collapse of numerous ice shelves, particularly those located in the northern and western regions of the Antarctic Peninsula. As a result of these collapses, glaciers feeding these floating ice shelves have accelerated their ice flows, leading to thinning.

In November 2023, the Centro de Estudios Científicos (CECs) and the Chilean Navy conducted aerial surveys over the Antarctic Peninsula to collect high-resolution surface topography, subglacial topography, and internal structure data of the Antarctic ice masses. A suite of instruments mounted on a Lockheed P-3 Orion aircraft, was utilized for measuring these ice characteristics. These systems were developed, and integrated in Chile by CECs. The survey comprised four flights, covering a total measured distance of around 7,000 km.

This dataset, along with its comparison to previous results, will enhance our understanding of the ongoing changes in glaciers and ice shelves of the Antarctic Peninsula. It will also provide insight into the processes influencing ice loss, facilitating more accurate future estimates of global sea level rise and the potential impacts of climate change on the cryosphere.

153

Intrinsic Instabilities of the Antarctic Slope Current along an Idealized Continental Slope

Dr. Chengyan Liu¹, Prof. Zhaomin Wang¹, Dr. Xi Liang², Dr. Xiang Li¹, Xianxian Han¹, Dr. Chen Cheng¹

¹Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China. ²National Marine Environmental Forecasting Center, Beijing, China

Abstract

The Antarctic Slope Current (ASC), coupled with the Antarctic Slope Front (ASF), encircles Antarctica and is a roughly longshore flow. Yet, the instabilities of the ASC/ASF can induce cross-slope exchanges. The ASC/ASF instabilities excited by external forcing have been studied extensively in previous literature. However, the mechanisms responsible for the intrinsic instabilities are still not clear. Based on an idealized eddy-resolving model, this study focuses on the intrinsic instabilities of the ASC/ASF. The ASC/ASF is classified into three types: Fresh Shelf, Warm Shelf, and Dense Shelf. Focused on the Fresh Shelf and Dense Shelf cases, two high-resolution process-oriented numerical experiments are conducted to reveal the typical characteristics, the dynamic mechanisms, and the influences of the intrinsic instabilities. In the Fresh Shelf case, the intrinsic instabilities are characterized by a submesoscale vortex train over the middle-lower slope, associated with the Topographic Rossby waves. In the Dense Shelf case, a mesoscale vortex train is present over the lower slope, and abundant filaments and jets can flow across the shelf break. The baroclinic instability greatly contributes to the generation of intrinsic instabilities in the two cases, yet the barotropic instability contributes less to the intrinsic instabilities in the Fresh Shelf case. As a unique feature of the instabilities, coherent eddies have been identified and significantly favor the cross-slope exchanges by the advection of water boluses retaining source water. The eddy-induced transport cannot cross the shelf break in the Fresh Shelf case but effectively results in cross-slope exchanges in the Dense Shelf case.

158

Understanding the Plankton diversity and ecosystem processes in the Indian sector of Southern Ocean and coastal Antarctica climate change scenario

Dr. RAJANI KANTA MISHRA¹, Mr. Sreerag A², Dr. V Venkataramana¹, Dr. Melena A Soares¹

¹NCPOR, Vasco-da-Gama, Goa, India. ²NCPOR, Vasco-Da-Gama, India

Abstract

The global environmental changes owing to natural and anthropogenic influences are challenging the structure and functioning of the ocean ecosystem. The complex processes interacting within the physical, chemical, and biological environment at different spatio-temporal scales and their impact on the ocean ecosystem processes are yet to be investigated. The Southern Ocean and coastal Antarctica ecosystem (SOCAE) is an important region with global significance in terms of its role in climate change and its variation. The SOCAE is particularly an underexplored region. The SOCAE observation was carried out to study the climatic variability on regional and global scales and their implications on living resources, biogeochemical cycles, and ecosystems. Further aims to understand Southern Ocean meridional, overturning circulation and intermediate as well as bottom water mass impact the thermohaline variability, CO2 dynamics/acidification rate, biogeochemistry, and the climatic variability. Also, understanding the Air-Sea-Ice interaction in the region of SOCAE influences the freshening and warming of water on the community structures, primary and secondary productivity, ecosystems, and food web dynamics. A long-term trend on phytoplankton biomass regarding Chlorophyll-a concentration (Chl-a), phytoplankton/zooplankton compositions, and the processes controlling the variability is required to understand the ocean ecosystem. The photosynthetically available radiation (PAR) limits the phytoplankton biomass and compositions in the study region. Although the SO is known as the high nutrient low chlorophyll (HNLC) region of the Global Ocean (GO), the low iron concentration and PAR co-limits the growth of phytoplankton biomass. Trend analysis showed an increase in biomass and diatoms in the SO. In contrast, it declined significantly in the other regions of the GO in response to the consistent rise in sea surface temperature. The results indicated that shifting the phytoplankton community from a regional to a global scale has a greater implication for climate change and the marine ecosystem.

159

Temporal fluctuations of organic pollutants in Antarctic coastal waters: Insights from Admiralty Bay, Antarctica Peninsula

Amanda Souza¹, Josilene Silva¹, Dr. Satie Taniguchi¹, Dr. César Martins¹, Dr. Tatiane Combi², Dr. Rafael Lourenço¹

¹São Paulo University, São Paulo, Brazil. ²Federal University of Paraná, Pontal do Paraná, Brazil

Abstract

Coastal regions of Antarctica experience abrupt climatic variations during the austral summer, characterized by a rise in temperature and glacier melting. This leads to a subsequent rise in freshwater and suspended particulate matter (SPM) inputs, transporting organic matter, contaminants, and nutrients from land to the marine environment. This study aims to evaluate the temporal variations of persistent organic pollutants (POPs; including polychlorinated biphenyls and organochlorine pesticides) and polycyclic aromatic hydrocarbons (PAHs) in the water column of Admiralty Bay, Antarctic Peninsula, from late spring to late summer. Sampling was conducted in five campaigns during the 2022/2023 summer at 16 sites. Approximately 20 liters of surface water were vacuum filtered through GF/F Whatman^® (0.7 μm) filters to obtain the SPM. Analyses were performed on an Agilent Model 7890B gas chromatograph coupled to an Agilent Model 7010B triple quadrupole TQMS in multiple reaction monitoring mode. POPs exhibited an increasing trend towards the end of summer, with the average concentration increasing from 14.8 ± 10.77 ng g^-1 in December 2022 to 57.6 ± 22.88 ng g^-1 in March 2023. In contrast, PAHs (∑33 PAHs) showed a more regular temporal distribution (average: 2818.9 ± 1675.6 ng g^-1) with an increase only in mid-February. The difference in temporal patterns may be attributed to sources, as POPs trapped in soil, sediment, and ice over decades are released into water from secondary sources like melting. PAHs originate from local sources, including research station operations in Admiralty Bay. Furthermore, biodegradation and photodegradation make PAHs less susceptible to seasonal changes as higher temperatures and radiation in late summer can accelerate degradation processes. This study emphasizes short-term concentration variations and the complexity processes governing the occurrence of organic pollutants in the coastal waters of Admiralty Bay, highlighting the need to comprehend these phenomena for evaluating environmental impact and its response to climate change.

160

The Macro in the Micro: a case study from Edisto Inlet (Ross Sea, Antarctica)

Giacomo Galli^1,2, Professor Caterina Morigi², Doctor Ben Thuy³, Doctor Karen Gariboldi²

¹University of Ca'Foscari, Venice, Italy. ²University of Pisa, Pisa, Italy. ³Natural History Museum, Luxembourg, Luxembourg

Abstract

Paleoenvironmental reconstructions are used to understand the evolution of past environmental conditions in a particular area. Traditional approaches include geochemical, sedimentological, and micropaleontological proxies to retrieve different environmental characteristics. Micropaleontological analyses have traditionally focused on foraminifera, diatoms, and other microorganisms, correlating changes in species with the physiochemical characteristics of the environment. Nevertheless, microfossils belonging to macrofaunal communities have been poorly studied, especially for the Holocene. Here, we examine a marine sediment core (TR17-08) that spans the last 3.6 kyrs BP, located in the northwestern part of the Ross Sea. Our findings demonstrate that the use of macrofaunal microfossils, in the present case echinoderms, can yield detailed and complex information about recent past conditions. Two distinct groups were identified: ophiuroids (Ophionotus victoriae) and irregular echinoid. Estimating the populations size can be complicated due to the great number of ossicles released upon the decay of the dead organism. To address this, we utilized Generative Additive Models to model the presence/absence distribution over time. By comparing the model output with other proxies derived from the same record and ones derived from nearby cores, we were able to successfully use echinoderms as a new “macrofaunal proxy”. O. victoriae presence can be associated with interannually stable sea-ice cycles with yearly organic deposition, while simultaneously indicating periods of a mature benthic community. Irregular echinoids forms have been associated with the presence of organic matter on the seafloor. By comparing different proxies, we were able to distinguish specific climatic phases in accordance with previous studies, while revealing additional insight into the environmental evolution of the area, unattainable with traditional proxies. In conclusion, this study provides compelling evidence that the inclusion of macrofaunal-related proxies in paleoenvironmental reconstructions is crucial for capturing complex interactions between the environment and the ecosystem.

161

Viral Surveillance in the Antarctic: Insights into Coronaviruses and Influenza A Virus Among Bird Species

Fernanda Gomes, Dr Tatiana Prado, Dr Martha Brandao, Dr Paola Resende, Dr Win Degrave, Maithê Magalhães, Dr Gabriel da Luz Wallau, Dr Marilda Siqueria, Dr Maria Ogrzewalska

Fiocruz, Rio de Janerio, Brazil

Abstract

The potential for Antarctic species to act as reservoirs for pathogens and contribute to the emergence and circulation of new infectious diseases is a significant concern. The mention of H5N1 spreading from other continents and affecting native species is particularly worrying and could have devastating effects on the region's fragile ecosystems and unique wildlife. To address potential zoonotic risks, surveillance of influenza A virus (IAV) and coronaviruses (CoVs) was conducted in various localities in the South Shetland Islands in the Antarctic summer 2022/2023 as part of the Brazilian Antarctic Expedition specifically focusing on different bird species in the region. Viral RNA was extracted and the screening for the viruses was performed by quantitative one-step real-time RT-PCR (IAVs) and by the conventional pancoronavirus RT-PCR protocol (CoVs). A total of 243 environmental fecal samples (Stercorarius spp (N=5), Larus dominicanus (N=16), Phalacrocorax bransfieldensis (N=3), Pygoscelis adeliae (N=19), Pygoscelis antarcticus (N=38), Pygoscelis papua (N=139), Pygoscelis spp (N=23) were collected during the summer of 2022/2023 and analyzed to target these respiratory viruses. All samples were negative for influenza A and one sample from the colony of L. dominicanus at Keller Peninsula, King George Island, tested positive for CoVs targeting the RNA-dependent RNA polymerase (RdRp) gene region. The resulting 450 bp fragment was sequenced by Sanger sequencing. Phylogenetic analysis revealed this CoVs as closely related to avian deltacoronaviruses previously identified in P. papua from Isla Kopaitik, Base O'Higgin, and seagulls from Asia and Europe. The presence of CoVs in Antarctic seabirds raises concerns about their potential role in virus dispersion during intra and intercontinental migration routes. The findings contribute valuable insights into virus dynamics among seabird populations, laying the groundwork for future investigations in this field.

164

What inhabits the South Sandwich Islands deep-sea? Biodiversity and biogeography of bathyal communities using predators as biological samplers

José P. Queirós^1,2, Dr José C. Xavier^1,2, José Abreu^1,2, Dr Martin A. Collins², Dr Mark Belchier², Dr Philip R. Hollyman^2,3

¹University of Coimbra, Marine and Environmental Sciences Centre (MARE)/ Aquatic Research Network (ARNET), Coimbra, Portugal. ²British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Cambridge, United Kingdom. ³School of Ocean Sciences, University of Bangor, Bangor, United Kingdom

Abstract

Understanding the biodiversity of an ecosystem is crucial to determine its structure and resistance to climate change. The South Sandwich Islands (SSI) are located in the Scotia Sea (Southern Ocean), within the South Georgia and the South Sandwich Islands Marine Protected Area. However, the biodiversity of the archipelago remains poorly studied, whilst climate change has the potential for wide-ranging impacts the Antarctic and Subantarctic regions. Here we used predators as biological samplers to study the bathyal communities of SSI. A total of 61 species including fish, cephalopods and crustaceans, were identified from the diet of 13 predatory taxa (11 fish and two cephalopod). Common Antarctic and Subantarctic species were found, with Moroteuthopsis longimana being the species with the highest density (1.74 individuals per stomach at Montagu Island). Eleven fish and one cephalopod species were recorded for the first time at the archipelago. Furthermore, 16 fish species had their bathymetric range increased. Fifteen fish and one crustacean appear to have SSI as the northern or southern limit of their distribution. Community analysis found two major groups at SSI, one in the north and one in the south, with the southern group subdivided into two groups. This separation is related to the environmental conditions at the archipelago that abruptly change at Saunders Islands. Latitude (correlated with sea surface temperature) and sea surface height (proxy for upwelling) both correlated with the dissimilarity between communities. These results suggest that climate change may affect the biodiversity at SSI in the future as warming waters of the Scotia Sea and changes in the upwelling system may favour range extensions of more northerly species into the archipelago. This could lead to local extinctions of some species exclusively found in the southernmost areas of the archipelago.

168

Application of Artificial Intelligence & Remote Sensing (AIRS) to Study the Correlation of Climate Variability with Air-Sea CO₂ exchange Over the Pacific Oceanic regions (TAs & WBCs, to Develop ‘Asia-Pacific Sea Level Variability Predicting Models (AP-SLVPM).-

Prof.(Dr.) VIRENDRA GOSWAMI

IIT & Environment and Peace Foundation, NOIDA (NCR), India

Abstract

The seminal scientific research is needed to understand major Climate Challenges in the Asia-Pacific region resulting the extreme weather events e.g., severe storms, ocean acidification, rising sea levels, and disruptions to their ecosystems, due to mesoscale convective systems, Global Carbon Cycle, toxins and Marine Pollution, over the Oceanic and sub-surface Oceanic regions. Ocean Circulations, Ocean-Atmospheric (OA) interactions, and the inorganic contaminants get affected by the Ocean Salinity.

Researchers found that the Sea-level rise was due to rising levels of Carbon Dioxide and other GHG, as opposed to other types of forces. Hence, the correlation of climate variability with sea-level variability

The El Niño Southern Oscillation (ENSO) originates in the tropical Pacific Ocean TAs & are source of year-to-year climate variability. Transitional Areas (TAs) are the potential oceanic regions of early detection of Climate variability, and areas of strong gradients in the physical environment that challenge biological communities, and are associated with Sea-level Variability Mechanism, Sub-Mesoscale Dynamics over the Oceanic areas impacting the Climate change.

Western Boundary Current (WBC) are the Pacific oceanic regions of mid-latitudes in Northern Hemisphere. There is a complex interaction of Oceanic-Atmospheric dynamics and thermodynamics affecting the regional air–sea exchange processes and their larger-scale interactions. WBC are hubs for the subduction of anthropogenic carbon-laden waters into the ocean interior during mode water formation and are Ocean Carbon Hot Spots regions identified by the largest magnitude air-to-sea CO₂ fluxes in the oceanic regions incorporated with large spring blooms and high eddy activity.

To understand air-sea exchange during extreme atmospheric forcing, to correlate Air-Sea CO₂ exchange with Climate Variability for estimating energy and material (Carbon, Nitrogen) exchange between the upper and deep ocean sea level variable processes Mechanism, the sub-mesoscale dynamics would be computed by AIRS, and through the study of multi-scale ocean-atmosphere coupled processes to check the rising levels of Carbon Dioxide, in order to develop ‘Asia-Pacific Sea-Level Variability Predicting Models (AP-SLVPM).

174

Beagle Channel: meeting point for culture and science

Magister Francisco Sánchez

Fundación Huellas Magallanicas, Punta Arenas, Chile

Abstract

The Beagle Channel, in the subantarctic area of the American continent, represents a meeting point for different disciplines such as history, philosophy, biology, meteorology, among others, where strong maritime and scientific activity is carried out year after year, which It is necessary to value it by understanding its geographical characteristics and recent history.

In this way, the Beagle Channel represents a point of action for different state actors and the scientific community, where the generation of a cultural space with projections to Antarctic action is fundamental.

Its history is marked by exploration, border conflict between Chile and Argentina, as well as a point of maritime development and science where a projection and understanding of space unsuspected 50 years ago has been achieved.

The efforts in the formation of nuclei of scientific thought, rescue of ancestral culture as well as knowledge of a fundamental subantarctic area for the future, urge the development of research that allows us to understand its connection with the future of sustainable development in an isolated binational area.

175

The Maritime Authority in Antarctica: safeguarding the aquatic environment and human life at sea

Magister Francisco Sánchez

Armada de Chile, Punta Arenas, Chile

Abstract

The history of the Chilean Navy in the Chilean Antarctic Territory is linked to different actions, which in one way or another, have been part of moments of dedication and sacrifices of members of the Institution, many times having to know and record experiences to future generations and that to this day are essential to carry out work on the Antarctic continent.

It is in this way that the work of the Maritime Authority, as a technical entity with high response capacity, has allowed the generation of an often unknown history, which is manifested in tasks of maritime traffic control, search and rescue, guidance and guidance to sailors, protection of the marine environment, installation and maintenance of navigation aids, collection of meteorological data and generation of forecasts.

Understanding this history is essential, being a fundamental pillar of international cooperation and the actions of different nations and institutions on the Antarctic continent, generating ties of protection and protection of one of the most impressive places on our planet, which is a constant for more of 77 years of presence.

176

Study of atmospheric radiation and its relation to climate change.

Geophysics Katherine Bastidas

Universidad de Concepción, Concepción, Chile. Universidad Santiago de Chile, Santiago, Chile

Abstract

The study of atmospheric radiation stands as an essential tool to observe how the atmosphere is affected by climate change over time, since it is one of the most urgent challenges to address today, in order to understand the effects, it produces in the atmosphere and thus adopt mitigation measures.

In 2024, within the framework of a professional internship in Geophysics, the analysis of the data obtained from atmospheric radiation was carried out, covering the period from March 16, 2023 to February 8, 2024.

These data were collected by means of two types of radiometers: two pyrgeometers and two pyranometers, with one oriented towards the ground and the other towards the sky, respectively. Where a pyrgeometer measures the flux of infrared radiation and a pyranometer measures the incident solar radiation on the earth's surface. This analysis provided a detailed view of radiation variability and its relationship to the climate changes observed during that period.

The results obtained from the analyses revealed significant patterns in atmospheric radiation, highlighting seasonal fluctuations. Variations in the spatial and temporal distribution of radiation were also observed, indicative of changes in atmospheric composition and dynamics.

The interpretation of these findings suggests a direct influence of climate change on atmospheric radiation, with possible implications for regional and global climate. The understanding of these processes is essential to develop effective strategies for adaptation to climate change. It provides a clear and concise overview of the importance of this field of research and highlights the relevance of the data analyzed during undergraduate professional practice.

177

Generation of forecasts in Antarctica: challenges and projections

Magister Francisco Sánchez, Capitán de Corbeta Gonzalo Bertolotto

Aramda de Chile, Punta Arenas, Chile

Abstract

Meteorological science is essential to understand the dynamics in the atmosphere that are being generated in Antarctica, this has led to the development of different actions that have been led by the Maritime Meteorological Center of Magallanes and Chilean Antarctica.

This work, guided by the parameters of the Word Meteorological Organization, establishes the fulfillment of various tasks in the area, forming multidisciplinary teams that converge in data collection, analysis, processing and generation of forecasts that are fundamental for the different Antarctic operators.

It is in this way that, despite the advances in science and technology, it is necessary to understand the challenges that come with understanding the atmosphere and its implications in Antarctic operations, which are often conditioned by extreme climate, modifying their planning and reaction.

178

Antartic education in Uruguay

Antartic Education in Uruguay Natalia Piñón Borotra

Insitituto Antártico Uruguayo, Montevideo, Uruguay

Abstract

Antarctica is a charismatic continent to work with students in the classroom. It is portrayed as a unique ecosystem inhabited by specific fauna and flora that captivates children and young people when they allow themselves to be trapped by its magic. In Uruguay, the Department of Education of the Uruguayan Antarctic Institute has been working since 2018 on the importance of Antarctica in the educational agenda by proposing different activities to educators. These are aimed at allowing the development of students' interests, bringing the scientific community closer to the classroom, and enriching the citizens in general. The activities with the greatest impact, generating new opportunities for development year after year are: talks on specific topics of flora and fauna, and adaptations of living beings to extreme weather conditions; building of 3D models of Antarctica, simulations of situations in the Artigas Antarctic Scientific Base; direct contact with the Base staff through virtual connections, exchanges with scientists and research projects, applying project-based methodologies to approach researchable questions, among others, that defy the educators to work in an interdisciplinary and sometimes multilevel way. Proposals submitted by undergraduate, specialization and master's degree programs of the University are also supported, when they have areas of promotion and training that allow to unify criteria and promote joint lines of work. During 2023, talks open to the public were held thanks to the collaboration of prestigious teams of national scientists from the University of the Republic in agreement with the Dr. Torres de la Llosa Museum of Natural History, with an attendance of more than 200 people in the series of talks "Talking about Antarctica". Antarctica offers Uruguayan educators unique work opportunities that should continue to be explored and developed due to the importance, richness and ecosystem services Antarctica offers to all at a global level.

180

Antarctic vascular plant collection: challenges and progress.

Dra. Marely Cuba-Díaz^1,2, Dr. Darío Navarrete-Campos¹, C. Dra. Yadiana Ontivero-Vasallo^1,3, Ing. Macarena Klagges¹, Ing Solange Alveal¹, Ing Constanza Salgado¹, Ing Francisca Arroyo¹, Tomás Soto¹, Marilin Carrasco¹

¹Laboratorio de Biotecnología y Estudios Ambientales, Departamento de Ciencias y Tecnología Vegetal, Escuela de Ciencias y Tecnologías, Universidad de Concepción Campus Los Ángeles, Los Ángeles, Chile. ²Programa de Ciencia Antártica y Subantártica, Universidad de Concepción, Concepción, Chile. ³Programa de Doctorado en Ciencias de la Agronomía, Facultad de Agronomía, Universidad de Concepción Campus Chillán, Chillán, Chile

Abstract

Antarctica, considered a pristine system, is at the forefront of interest when we talk about the climate crisis. Only two vascular plants (Deschampsia antarctica and Colobanthus quitensis) are native to this ecosystem, although the introduction of other non-native species has been reported. The use of these "model" species to understand adaptation and resilience mechanisms, but also as a source of biotechnological and conservation applications, is increasingly relevant. As part of the environmental protection agreements and the International Antarctic Treaty, Specially Protected Areas and other in situ conservation and protection safeguards have been developed for genetic heritage in Antarctica. However, various research can be carried out using material preserved and protected ex situ. In our laboratory we have a Collection of Antarctic Vascular Plants, which for 13 years has been enriched with material from different sources, facilitating various research, scientific collaborations, and the formation of human resources. The collection is maintained from seeds obtained ex situ, or through vegetative propagation in vitro or in a common garden. We currently have 15 accessions and progress has been made in: propagation and conservation protocols, elucidating mechanisms of tolerance to abiotic conditions in different populations, analyzing interactions between native and non-native species in the face of climate change; understand the phylogeography of C. quitensis and its evolutionary history, and in biotechnological applications such as: development of mutants, induction of callogenesis and cell suspensions, genetic transformation, prospecting for secondary metabolites and abiotic elicitation of compounds of biological interest. Progress of these results and challenges will be shown.

181

Differential morphophysiological and biochemical response to salinity in populations of Colobanthus quitensis KUNTH (Bartl.).

Dr. Dario Navarrete¹, Ing Francisca Arroyo¹, Ing Thiare Aguilers¹, Dra Marely Cuba-Díaz^1,2

Abstract

Salinity in soils limits plant growth, development, and survival. It is estimated that by 2050 more than 50% of arable land will be salinized. Several conventional breeding programs have focused on salinity, but their mechanisms are genetically and physiologically complex. Only basic research focused on deepening these mechanisms will make it possible to design effective strategies. It has been suggested that Colobanthus quitensis, a plant native to Antarctica, could tolerate salinity due to being exposed to constant sea spray. This species is also distributed in areas flooded by high tides and in others without marine influence, constituting an excellent model to investigate differential responses to salinity. In this research, morphophysiological and biochemical variables of 5 populations of C. quitensis (2 Antarctic and 3 Magellanic; 2 from sea flooded areas and 1 without marine influence) are evaluated to differentiate their responses to salinity. The experiment was carried out in vitro and concentrations of 0, 50, 100, 150 and 200 mM of NaCl were evaluated. The Magellanic populations presented a better tolerance to increased salinity, while the Antarctic populations presented a reduction in biomass and root growth, negatively affecting their growth and morphology. These same populations showed a significant decrease in the activity of redox enzymes and significant increases in proline content at lower concentrations of NaCl than the Magellanic ones. Furthermore, the Magellanic populations showed stable contents of K+ ions with the increase in Na+ ions, but not the Antarctic populations. These results show that Antarctic populations, exposed to sea spray, tolerate less salinity than Magellanic populations. The question of whether the coastal Magellanic populations are more tolerant requires more studies, since the population without marine influence showed significant differences in few of the variables evaluated. In addition, the research strategies currently underway will be presented.

182

Low-cost germination in vitro for introduction of Deschampsia antarctica to the Antarctic plant collection.

Marilin Carrasco¹, C. Dra Yadiana Ontivero-Vasallo^1,2, Dr. Dario Navarrete-Campos¹, Dr Gustavo Cabrera-Barjas³, Dra Marely Cuba-Díaz^1,4

¹Laboratorio de Biotecnología y Estudios Ambientales, Departamento de Ciencias y Tecnología Vegetal, Escuela de Ciencias y Tecnologías, Universidad de Concepción, Campus Los Ángeles, Los Ángeles, Chile. ²Programa de Doctorado en Ciencias de la Agronomía, Facultad de Agronomía, Universidad de Concepción Campus Chillán, Chillán, Chile. ³Universidad San Sebastián, Facultad de Ciencias del Cuidado de la Salud, Universidad San Sebastián Campus Las Tres Pascualas, Concepción, Chile. ⁴Programa de Ciencia Antártica y Subantártica, Universidad de Concepción, Concepción, Chile

Abstract

The native Antarctic vascular flora, represented by only two plants, Colobanthus quitensis and Deschampsia antarctica, is limited to very small spaces and extreme environmental conditions. Both species have become interesting “models” for studies of response to extreme environments and as sources of metabolites of biological interest. Access restrictions and protection measures for the development of research with these two species are overcome by ex situ collections. Both species are represented in the Antarctic Vascular Plant Collection of the University of Concepción, where the protocols for their propagation and conservation in vitro or in a common garden are being constantly improved. Several investigations have reported in vitro culture protocols for D. antarctica, but only one recent work has exposed successes in germination under controlled conditions in this species, with long germination times and high-cost culture media. In this work, two disinfection methods were evaluated: 15% H₂O₂ (D1) or 70% Ethanol for 30 s, then 15% Na hypochlorite + 0.05% Tween 20 for 10 min (D2), the use of osmotic treatment (5% KCl) prior to germination or not, as well as two basal media: Agar/Sucrose 3% or Murashige and Skoog (MS) at half the concentration/ Sucrose 3%, and the use of chitin nanofibers (0.01% ) or not in the germination medium. With method D1, a contamination of 18.5% was obtained, while with D2 the contamination was of 87.5%. The combination of KCl+ MS+ chitin nanofibers showed the highest germination percentages at 15, 30 and 60 days with with 11.1, 26.7 ± 7.7 and 31.1 ± 6.4%, respectively. It is suggested that the use of chitin nanofibers stimulated germination, however, other variables such as the need for scarification and the quality of the seeds at the time of use.

183

Callogenesis in Colobanthus quitensis: an alternative for the conservation, and use of the species in biological applications.

Tomás Soto¹, Ing Macarena Klagges¹, Dr. Gustavo Cabrera-Barjas², Dra Marely Cuba-Díaz^1,3

¹Laboratorio de Biotecnología y Estudios Ambientales, Departamento de Ciencias y Tecnología Vegetal, Escuela de Ciencias y Tecnologías, Universidad de Concepción, Campus Los Ángeles, Los Ángeles, Chile. ²Facultad de Ciencias del Cuidado de la Salud, Universidad San Sebastián, Campus Las Tres Pascualas, Concepción, Chile. ³Programa de Ciencia Antártica y Subantártica, Universidad de Concepción, Concepción, Chile

Abstract

Colobanthus quitensis (Caryophyllaceae) has naturally colonized the Antarctic, overcame geographical and environmental impediments, and demonstrated resilience to strong abiotic stresses and climate change. These characteristics have increased scientific interest in C. quitensis in recent times. Due to limited accessibility to the Antarctic, ex situ conservation of C. quitensis through tissue culture is necessary to provide constant material for studies and to conserve the diverse populations of the species that are threatened by the increasing anthropogenic activity in the region. Although protocols for in vitro preservation through minimal growth and direct organogenesis already exist, obtaining a protocol for callus culture in C. quitensis would expand the options for plant material, making possible studies on secondary metabolites with potential biotechnological applications. Therefore, this study aimed to develop the first protocol for obtaining friable callus in the Arctowski population of C. quitensis. In the first experiment, callus induction was carried out in three explants (seed, hypocotyls, and shoots) using 2,4-Dichlorophenoxyacetic acid and Picloram; each at different concentrations (1 mg/L, 1.5 mg/L, and 2 mg/L) in basal Murashige & Skoog medium. After 3 months, induced callus and plantlets were subjected to saline treatment with different concentrations of NaCl to evaluate the effect on antioxidant capacity and total phenols. Thus; 2,4-D proved to be the most suitable for the induction of friable callus. Hypocotyl and shoot calli had a higher induction rate meanwhile the highest antioxidant capacity and total phenol content was achieved in hypocotyl callus. In the second experiment, the effect of basal medium was evaluated using MS and B5 media along with 1.5 mg/L of 2,4-D to induce callus from new explants (plantlet, root, and leaf). Friable callus was obtained only in the presence of MS medium, the highest induction rate was achieved in plantlet callus in MS medium.

184

Monitoring vegetative and reproductive development of Colobanthus quitensis populations: a conservation strategy.

C. Dra. Yadiana Ontivero-Vasallo^1,2, Dra. Marely Cuba-Díaz^1,3, Constanza Salgado¹, Dr. Dario Navarrete-Campos¹, Vicente Carrillo¹

¹Laboratorio de Biotecnología y Estudios Ambientales, Departamento de Ciencias y Tecnología Vegetal, Escuela de Ciencias y Tecnologías, Universidad de Concepción Campus Los Ángeles, Los Ángeles, Chile. ²Programa de Doctorado en Ciencias de la Agronomía, Facultad de Agronomía, Universidad de Concepción Campus Chillán, Chillán, Chile. ³Programa de Ciencia Antártica y Subantártica, Universidad de Concepción, Conceoción, Chile

Abstract

The study of soil characteristics and plant growth is essential to know their degree of conservation and the future dynamics of their populations. Colobanthus quitensis is a bioindicator of climate change, so it is essential to study its populations. We proposed to analyze the nutritional characteristics of the soil where C. quitensis grows and their influence on its growth and reproduction. During the Antarctic Scientific Expedition 59, three populations were monitored: in Byers Peninsula (pBy), Arctowski Station (pA) in Antarctica, and in La Marisma sector (pPA) in Punta Arenas. Fifteen plant cushions and rhizosphere soil were taken for nutritional analysis. Plant biomass, water content, number of seeds per flower, area and perimeter of the seeds, and weight of 100 seeds were determined. pA soil had the highest content of organic matter (3.27%), phosphorus (315.27 mg/kg) and potassium (618.33 mg/kg), while in pBy the organic matter content barely exceeded 1%. Monitoring showed that all 3 populations were reproducing, although fewer specimens of pPA were detected. pA had higher nitrogen and phosphorus contents. pPA showed the lowest biomass (0.78 g) but the highest seed weight (8.28 mg). pBy produced a higher number of seeds per plant (21 seeds), but of smaller area and perimeter. There is a positive correlation between soil phosphorus content with biomass and plant phosphorus and potassium levels, as well as between plant nutrient content and seed area. It is concluded that, the nutritional conditions of the soil in Arctowki Station favor the development of C. quitensis, ensuring the best nutritional status of the plants. pA and pPA produce the biggest seeds, although pPA produces heavier seeds. The higher seed production of pBy may be a strategy to ensure the survival of the species in Antarctic.

185

Project ¨Plant biotechnology: application and vocational training of young people¨: a resource that uses Antarctic research to promote the study of scientific careers in Los Ángeles, Chile.

C. Dra. Yadiana Ontivero-Vasallo^1,2, Dra. Marely Cuba-Díaz^1,3, Vicente Carrillo¹, Solange Alveal¹, Dario Navarrete-Campos¹, Tomás Soto¹, Benjamín Sepúlveda¹, Francisca Arroyo¹, Constanza Salgado¹, Thiare Aguilera¹, Macarena Klagges¹, Marilin Carrasco¹

¹Laboratorio de Biotecnología y Estudios Ambientales, Departamento de Ciencias y Tecnología Vegetal, Escuela de Ciencias y Tecnologías, Universidad de Concepción, Campus Los Ángeles, Los Ángeles, Chile. ²Programa de Doctorado en Ciencias de la Agronomía, Facultad de Agronomía, Universidad de Concepción, Campus Chillán, Chillán, Chile. ³Programa de Ciencia Antártica y Subantártica, Universidad de Concepción, Concepción, Chile

Abstract

Despite the availability of university STEM careers in Chile, every year fewer young people are interested in STEM, so it is necessary to work intelligently in vocational training. For this reason, undergraduate students of Plant Biotechnology Engineering and academics at the Laboratorio de Biotecnología y Estudios Ambientales (LABEA) of the Universidad de Concepción (UdeC), Campus Los Ángeles, in the framework of the project: “Plant biotechnology: application and vocational training of young people” carried out didactic activities to promote vocational training around the study of scientific careers with emphasis on plant biotechnology. For one year, talks were given in the schools Padre Alberto Hurtado, Liceo Coeducacional Santa María de Los Ángeles and Colegio San Rafael Arcangel, in Los Ángeles city, Chile on: (1) What is science and Plant Biotechnology, (2) Scientific careers and where to study them, (3) Biological models in science and (4) Antarctic research lines of LABEA. Many students were curious about the fact that Antarctica is a place with life and where Chilean and international institutions carry out a great variety of research, many of them focused on plants. A tour of the Los Ángeles Campus was conducted, this being the first approach for many of these young people to a university campus and its laboratories. In addition, 2 laboratory activities were carried out where the processing of seeds of the Antarctic plant Colobanthus quitensis, the development of seed viability tests with tetrazolium salts and in vitro tissue culture were taught, where the young students actively participated in the preparation of culture media, obtaining explants and their sowing. This experience showed that vocational training provided by UdeC students is a successful strategy to achieve better communication with young people and that there is little knowledge about how much research can be done if scientific careers are studied.

186

Eddy Detection in the Antarctic Marginal Ice Zone from Sentinel-1 Data Using YOLOv5

1 Ekaterina Marchuk¹, 2 Nikita Sandalyuk², 3 Eduard Khachatrian³

¹Obukhov Institute of Atmospheric Physics, Moscow, Russian Federation. ²The Moscow Institute of Physics and Technology, Moscow, Russian Federation. ³UiT The Arctic University of Norway, Tromsø, Norway

Abstract

Marginal ice zones (MIZs) are regions with energetic atmosphere–ice– ocean interactions, enhanced biological productivity and strong lateral buoyancy gradients. With continuing global warming, MIZs remain a major source of uncertainties in sea ice prediction models because of poor representation of thermodynamic sea ice processes, including the effects of lateral melt, which has been associated with the development of ocean eddies as a result of lateral buoyancy gradients. Mesoscale eddies, which typically occur on length scales of kilometers and time scales of hours to days, play a key role in ocean vertical and horizontal mixing and heat and nutrients transport.

Many researches were dedicated to the detection of mesoscales and submesoscales eddies using altimetry data. Another set of studies is devoted to detecting mesoscale and submesoscaleseddies in the ocean in the Arctic region using artificial intelligence. The novelty of this work lies in the fact that we applied an artificial intelligence algorithm trained to recognize Arctic eddies to eddies formed in the Antarctic melting zone.

The study region extends from 5° to 75° E and from 33 to 71° S. The dataset was generated from Sentinel-1 SAR imagery in an extra-wide (EW) swath mode at dual-polarization (HH and HV). SAR images was selected because of its independence from atmospheric and light conditions, that is especially vital for polar areas. The collected dataset includes 176 scenes for the duration of 2022, which cover the melting and ice formation season over the area of the Lazarev Sea, Riser– Larson Sea, Cosmonaut Sea, and Commonwealth Sea.

Then, a state-of-the-art object detection algorithm YOLOv5, trained in previous studies on similar satellite images in the Arctic region, was applied to the detection of submesoscale eddies in the MIZ of Antarctica.

187

Paleo-oceanographic environment of the Drygalski Trough since the Last Glacial Maximum, Ross Sea, West Antarctica

Zijian Xiao^1,2, Prof. Xiaoxia Huang¹, Dr. Xun Yang¹

¹Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China. ²University of Chinese Academy of Sciences, Beijing, China

Abstract

Abstract: The Ross Sea is located in the West Antarctica and mostly covered by the Ross Ice Shelf, which is the largest ice shelf in the world. The continental shelf of the Ross Sea holds three large subparallel sedimentary basins that are the Victoria Basin, the Central Trough, and the Eastern Basin. The deepest area of the continental shelf is located at the Drygalski Trough in the Victoria Basin, with a water depth over 1,100 m. Previous studies have indicated the classification of subglacial sediments, but there was no further discussion of sedimentary hydrodynamic conditions beneath the ice sheet. Hence, a gravity core of 1.16 m which was successfully collected in the Drygalski Trough during the China's 39th Antarctic Expedition in 2023 were analyzed the XRF, XRD, grain size, and isotope dating to obtain the mineral composition and access the sedimentation processes. The results indicate the diamicton gradually decreases in gravel content and size with depth and a relatively high input of terrigenous deposits at the bottom of the core. The magnetic susceptibility is in consistent with the adjacent cores, which demonstrate that the oldest sediments were accumulated during the Last Glacial Maximum (LGM). Hence, the trough had received subglacial sediments since around 20 ka. This study further reveals the Drygalski Trough experienced complicated paleo-hydrodynamic conditions evolution during the LGM and after the retreat of the ice sheet. The reconstruction of the past glacial activities and the evolution of the depositional environment in the Drygalski Trough provides key information for predicting the impacts of future glacier changes and improving the accuracy of glacier-ocean models.

Key Words: Drygalski Trough; Ross Sea; ice sheet dynamics; sediment cores; palaeoceanographic evolution; Antarctica Zone.

189

Paleo-bathymetric Evolution of Prydz Bay since Eocene-Oligocene Boundary, East Antarctica

Zijian Xiao^1,2, Prof. Xiaoxia Huang¹

¹Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China. ²University of Chinese Academy of Sciences, Beijing, China

Abstract

Prydz Bay is the third largest bay in Antarctica after the Weddell Sea and the Ross Sea, which located in the East Antarctic continental margin and covered by Lambert Glacier-Amery Ice Shelf. Prydz Bay is also the largest glacier discharge channel to the sea in the East Antarctic, accounting for about 20% of East Antarctica and 9% of whole Antarctica. Previously studies suggested the sediments in Prydz Bay basin were found to be up to 12 km thick and recorded the basin sedimentary evolutionary history primely. Prydz Bay is covered by rich multi-channel seismic lines and Ocean Drilling Program Leg 119 and 188 provided available data of 8 boreholes which used in this study, making it an ideal area for basin analyses and studies of paleo-bathymetric evolution. Cores porosity information indicated that the stratigraphy in the continental shelf is overcompacted due to grounded glacier loading, while the slope exhibits normal semi-pelagic sedimentary characteristics. This study used the backstripping method, combined with boreholes information, bathymetric data, seismic surveys, and regional tectonic information. Considering the variability of deposition processes, suitable parameters were used to calculate the compaction differences between continental shelf and slope sediments respectively. By comparison with previous studies the results of this study quantitatively infer the thickness of sediments and more finely reconstruct the paleo-bathymetry and the seafloor geomorphology in different stage since Eocene-Oligocene boundary. The results after backstripping contribute to the discussion of the depositional response of ice sheet dynamics and ocean circulation changes. Furthermore, gridded data could be used to establish more realistic glaciers, ocean currents and climate models, and promote the research progress on the paleo-sedimentary environment evolution analysis of the Prydz Bay.

190

Science and Law in the Polar Regions: Hierarchy, Dependence, or Symbiosis?

Medy Dervovic

Reykjavík University, Department of Law, Reykjavík, Iceland. Arctic Centre, University of Lapland, Rovaniemi, Finland. Stefansson Arctic Institute, Akureyri, Iceland

Abstract

Scientific understanding embodies a fundamental pillar of Arctic and Antarctic governance. As such, the idea of integrating science in international law-making is particularly well entrenched in the governance of the Polar regions. Years after the first efforts in this regard, it is time to characterize the relationship between science and law before assessing whether a stronger law-science nexus is necessary or (even) desirable. This presentation will primarily focus on the 1980 Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) and the 2018 Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean (CAOFA). Accordingly, the law-science nexus therein will be analyzed successively through the lens of hierarchy, dependence, and symbiosis. These three notions enable the visualization of different levels of integration of science in legal processes. Hierarchy implies a relationship characterized by the systematized subordination of one element to another. Dependence relates to the reliance of an element to another. Symbiosis, a term borrowed from natural sciences, refers to a long-lasting and mutually beneficial relationship between two different elements.

The need to reinforce the law-science nexus in the Polar regions will then be evaluated on three levels: creation, implementation, and revision of international law. This presentation will bring comparative perspectives from these two legal instruments. Particular attention will be put on, inter alia, treaty-making mechanisms and implementing tools. This assessment endeavors to identify similarities and differences in how science has been integrated into these legal processes. Eventually, it will be the opportunity to track the evolution of the law-science nexus in the Polar regions, considering that CCAMLR and CAOFA were adopted four decades apart.

191

First illustrated bi-lingual identification guide to phytoplankton of the Antarctic Peninsula for a non-scientific audience

MSc Celeste Kroeger-Campodónico^1,2, PhD Martina Mascioni³, PhD(c) Allison Cusick⁴, Ingrid Céspedes⁵, PhD Maria Vernet⁴, PhD Rick Reynolds⁴

¹Núcleo Milenio NUTME, ECIM, Las Cruces, Chile. ²Red de Educación Lationamericana para el Océano RELATO, Las Cruces, Chile. ³Universidad de La Plata, Buenos Aires, Argentina. ⁴Scripps Institution of Oceanography, San Diego, USA. ⁵Suroeste Films, Viña del Mar, Chile

Abstract

The FjordPhyto citizen science project, established in 2016, partners oceanographers with travelers and guides aboard member vessels of the International Association of Antarctic Tour Operators (IAATO). For five months every summer, citizen scientists collect phytoplankton from the western Antarctic Peninsula. These samples help researchers identify the phytoplankton communities and changing dynamics from melting glaciers due to climate change.

In 2020 scientists started creating the first illustrated identification guide of Antarctic phytoplankton for a non-scientific audience, to be used in the field and aboard ships. This bi-lingual (English, Spanish) book includes microscope photos and illustrations of more than 80 phytoplankton genera such as diatoms and dinoflagellates commonly found in the FjordPhyto samples. The book aims to be a visual way of connecting people with the wonderful world of phytoplankton, to provide travelers an identification key to recognize these small microscopic organisms, and to share stories that teach about the key role they play in the Antarctic ecosystem.

A prototype of the book was already tested on 10 ships (seasons 2021-2022 and 2022-2023). Overall the travelers response to the prototype was good and the guides considered it was a very helpful tool to identify phytoplankton species under the miscroscope onboard. Some minor changes were made after the tour guides feedback. Its final printed version will probably be available by the end of 2024.

194

Physical -biological drivers modulating sea-air CO₂and O₂ fluxes along the Patagonian shelf-break

BSc. Luísa Garcia¹, Dr. Iole Orselli¹, Prof. Virginia Maria Tavano¹, Prof. Carlos Rafael Mendes¹, Prof. Rosane Ito², Prof. Catherine Goyet³, Prof. Rodrigo Kerr¹, Prof. Carlos Garcia⁴

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Universidade de São Paulo, São Paulo, Brazil. ³Université de Perpignan, Perpignan, France. ⁴Universidade Federal de Santa Catarina, Florianópolis, Brazil

Abstract

Considering that oxygen (O₂) and carbon dioxide (CO₂) are subject to mainly the same biological and physical drivers, investigating these parameters together provides a comprehensive framework for elucidating the mechanisms that govern both O₂ and CO₂ sea-air fluxes. To do this, we analyzed data collected between 2004 and 2009 during spring and summer on the Patagonian Continental Shelf. Temperature, salinity, and O₂ measurements were conducted at each oceanographic station. The multiple linear regression technique was applied to develop four distinct algorithms for surface seawater CO₂ partial pressure. Phytoplankton biomass was discerned into different groups using information from pigment composition obtained by high-performance liquid chromatography (HPLC). Based on the frontal structures of the Patagonian Shelf and the drivers of CO₂ and O₂ fluxes, three regional areas were delimited and provide new insights into the processes governing these fluxes in the study area. Between 36° and 40°S, a wide range of temperature and salinity values, combined with lower phytoplankton biomass, were associated with higher group diversity, including dinoflagellates, diatoms, and haptophytes. Despite lower phytoplankton biomass, photosynthesis demonstrated significant importance in modulating CO₂ and O₂, likely due to the predominance of diatoms. Between 40° and 50°S, the shelf-break favored high phytoplankton biomass, associated with the highest positive O₂ fluxes (outgassing) from the entire shelf, and moderate CO₂ uptake. Besides photosynthesis, thermal processes also exhibited significant control over CO₂ ingassing and O₂ outgassing, often associated with the intrusion of relatively cooler subantarctic waters and their warming during summer. South of 52°S, the shift in behavior from a CO₂ sink to a source was associated with lower phytoplankton biomass along with the lowest sea surface temperatures. Thus, the main findings here can be used to predict the potential consequences of future climate-driven changes in ocean CO₂ (O₂) ingassing (outgassing).

195

Regional and latitudinal comparison of leopard seal moult reveals the importance of ice, climate, and seasonality

Mr Alexander Grabham^1,2, Dr Douglas Krause³, Dr Jorge Acevedo⁴, Dr Krista van der Linde^1,2, Mr Nicolás Fernández-Ferrada⁵, Dr Ingrid Visser², Miss Pippa Low⁶, Dr Renato Borras-Chavez⁷, Dr Sarah Kienle⁷, Dr Ted Cheeseman^8,6, Dr Ximena Nelson¹

¹University of Canterbury, Christchurch, New Zealand. ²Leopardseals.org, Kaikōura, New Zealand. ³NOAA Fisheries, La Jolla, USA. ⁴Centro Regional de Estudios del Cuaternario de Fuego-Patagonia y Antártica, Punta Arenas, Chile. ⁵Universidad de Valparaíso, Valparaíso, Chile. ⁶Happywhale, Santa Cruz, USA. ⁷Baylor University, Waco, USA. ⁸Southern Cross University, Lismore, Australia

Abstract

The dispersion of leopard seals (Hydrurga leptonyx) across the ice and non-ice environments of their distribution range may help predict the effects of climate change on polar seals. We collected 1199 predominantly photographic records of moulting leopard seals recorded between 23.06 and 75.51 ̊ S from 1976 to 2023 and visually assessed moult stage, progression, pattern, and timing, and compared these across regions of their range. Leopard seals exhibited two distinct types of active moult (i.e. pelage loss and growth), which we termed typical and atypical active moult (TAM and AAM, respectively). TAM was moulting where pelage was lost and replaced concurrently. AAM included varying degrees of pelage loss that resulted in black areas of skin or short post-moult pelage away from body openings, usually prior to visible post-moult pelage. To investigate the relationship of active moult type with extrinsic and intrinsic factors, we collected (1) seven climatic variables, photoperiod, and environment type (ice/non-ice), (2) assessed health state (e.g., bony protrusions, skin disorders), and (3) identified the ‘expected period of moulting’ (EPOM) for adult leopard seals in their primary distribution range (December–March) as a proxy for the influence of highly seasonal polar conditions and reproductive hormone levels. Across regions and latitudes, TAM typically (98%) occurred in ice environments and inside the EPOM. In contrast, AAM typically (66%) occurred in non-ice environments, with pelage loss resulting in black areas primarily observed outside the EPOM (April–November) and pelage growth primarily inside the EPOM. Indicators of poor health, particularly skin disorders, were more prevalent in AAM and were possibly related to exposed skin from pelage loss. As ice cover decreases in rapidly warming polar regions, leopard seals, and other ice-dwelling pinnipeds are likely to experience increasing interruption of the typical active moult that could impact their health and survival.

196

Zooplankton community variability in the eastern Ross Sea: Lessons from multidisciplinary ocean observations

Dr. Svenja Halfter¹, Georgia K. Pollard², Jasmin B.T. McInerney¹, Karen Robinson³, Dr. Matthew H. Pinkerton¹

¹National Institute of Water and Atmospheric Research, Wellington, New Zealand. ²University of Waikato, Hamilton, New Zealand. ³National Institute of Water and Atmospheric Research, Christchurch, New Zealand

Abstract

Zooplankton are a key component in the Southern Ocean food web as they connect primary producers with higher trophic levels, such as fish, marine mammals, and seabirds. They also majorly impact the carbon downward flux and nutrient availability in the water column. Yet, climate change impacts, such as warming, ocean acidification, or shrinking sea ice, are less explored on a zooplankton community level. To monitor future changes, a baseline for zooplankton abundance and community composition is required first. Unlike phytoplankton, zooplankton still require extensive in-situ sampling, which is logistically challenging for remote regions, such as the Ross Sea. Last field season in January-March 2024, a team of researchers from New Zealand had the opportunity to join the Italian icebreaker RV Laura Bassi for a voyage to the understudied eastern Ross Sea. The zooplankton community was sampled along the Ross Ice Shelf and around Cape Colbeck as well as in the northwestern Ross Sea as a comparison. Deployments of gliders, Biogeochemical Argo floats, and CTDs provided essential environmental information and highlighted the advantage of integrating multiple observational platforms. Zooplankton samples were processed using the ZOOSCAN, which offers a faster throughput of samples relative to traditional morphological sample identification. Here, we will present the preliminary results from the available observational platforms, as well as the first zooplankton community data from the eastern Ross Sea in late summer. We discuss changes along the voyage transect, e.g., from a pteropod-dominated zooplankton community along the Ross Ice Shelf to a more copepod-dominated community around Cape Colbeck. Finally, we also recommend how to improve data sharing and collaboration in the eastern Ross Sea region to close remaining spatial and temporal observational gaps.

197

The extinction of experiences in nature as a determining factor in the global environmental crisis: the contribution of non-formal education spaces to children's perception of Antarctica.

Dra Julyana Pereira Simas, Dra Silvia Dotta

UFABC, Santo André, Brazil

Abstract

As a result of increasing urbanization and the consequent change in land use, current generations live in environments with less access to natural spaces, causing a disconnection between the population and nature, in a process called by Pyle (2002) as "extinction of experiences," which impacts involve the reduction of benefits for health and well-being, in addition to compromising the affinity for nature and the willingness to protect it. Among the leading causes is the loss of "orientation," or the reduction of emotional affinity for nature. In this context, interactions with nature during childhood play a crucial role due to their potential to influence experiences significantly throughout life. Based on this premise and considering Antarctica's role in the current climate change scenario, this study aims to investigate the social imagination related to the importance of preserving the polar regions. To this end, a group of children visited Sabina – Park School of Knowledge in Santo André, São Paulo, Brazil, a non-formal education space with numerous interactive activities. The focus of the visit was the Room of Life, which addresses the interdependence of the various forms of life with the human species and has a penguinarium. The setting is ideal for children to interact with the penguins. Then, a questionnaire was designed to understand the children's perception of the bird. As a result, inferences can be made about how children relate and create affinity with animals, as well as how they understand concepts related to habitat and environmental impacts, highlighting the importance of experiences in nature for their appreciation. Finally, it is expected to relate these results to children's perception of Antarctica and, with this, understand the variables involved in valuing global preservation.

198

The Antarctic Soils Explorer portal: delivering science and history to a new wider audience

Dr Pierre Roudier¹, Dr Thomas Caspari², Dr Iain Campbell³, Mr Robert Gibb¹, Dr Senzo Miya², Mr Tomas Burleigh¹, Mr Andrew Cowie¹, Dr Ursula Jewell², Kristin Wilson⁴

¹Landcare Research, Palmerston North, New Zealand. ²Landcare Research, Lincoln, New Zealand. ³Land and Soil Consultancy Services, Nelson, New Zealand. ⁴Victoria University of Wellington, Wellington, New Zealand

Abstract

The Antarctic Soils Explorer (https://antarctic-soils.landcareresearch.co.nz/) weaves together field observations, soil samples, laboratory data, photos, maps, personal anecdotes from early Antarctic soil scientists, and Māori connections to Antarctica. It delivers science communication and science contribution in a publicly accessible, multimedia, online web portal that uses the technology of “story-maps” (blending of storytelling and maps) to present the information as a series of topical stories.

Sitting behind the stories is an archive of 8,837 physical Antarctic soil samples, collected between 1964 and 1999, carefully migrated and curated within the National Soils Archive at Manaaki Whenua in New Zealand. These soil samples represent invaluable “time capsules” for assessing temporal changes in Antarctic soil properties, particularly as new analytical techniques become available, and this work ensures they are available to serve as such.

All the associated legacy data from field observations and laboratory-based physical and/or chemical analyses have been collated, documented, and linked to the physical samples. The data can now be explored within the portal and are available as download for future research. The data provide an important baseline reference for further scientific analysis on Antarctic soils and are of huge value to climate change research.

In addition, preservation of these Antarctic soils and soil information contributes mātauranga (knowledge and understanding) regarding this tāonga (treasure) and adds cultural richness to our understanding of Māori relationships with the land, from centuries-old Māori oral traditions on journeys South to Māori cultural symbols that have been erected at Scott Base since the late 1960s.

The Antarctic Soils Explorer delivers an inter-generational and inter-cultural record of a unique part of New Zealand’s scientific endeavour in the Antarctic. It provides a collective benefit to science and culture. Most importantly, it ensures findability and accessibility of scientific data as well as context within which that data was obtained.

199

Fingerprinting East Antarctic Ice Mass Loss During MIS5e from Far-Field Sea-Level Records

Prof Ian Goodwin¹, Prof Jerry Mitrovica²

¹University of New South Wales, Sydney, Australia. ²Harvard University, Cambridge, USA

Abstract

Southern Australia is situated in a sensitive geophysical location to discriminate between the unique ice mass loss fingerprints from West Antarctica, East Antarctica and Greenland. New high-resolution Last Interglacial (Marine Isotope Stage 5e MIS5e) relative sea level (RSL) proxy records from southern Australia reveal a major departure from the RSL regression predicted in all models of the glacial isostatic adjustment (GIA) process for the region and unambiguously identifies a significant ice sheet melting event, during the middle phase (125-120 ka) of the MIS5e. We estimate the magnitude of the RSL departure in RSL proxy records by applying a state-of-the-art GIA model that incorporates 3D viscoelastic Earth structure. Using the geographic variation in these GIA-corrected RSL departures, we apply a novel fingerprinting approach to estimate the source(s) of meltwater during this phase of the MIS5e. We conclude, using a Monte Carlo analysis that considers a wide range of possible ice melt sources from Antarctica and Greenland, that net ice sheet melting from the Wilkes and Aurora Basins in East Antarctica contributed 1.44±0.42 m of equivalent global mean sea level rise, and demonstrate that this estimate is robust with respect to uncertainties in the viscoelastic Earth model. This indicates a relatively stable East Antarctic Ice sheet (EAIS) during MIS5e with limited retreat of the George V and Sabrina Coasts. Our approach also informs on an early MIS5e sea-level rise contribution from WAIS and a mid-late MIS5e contribution from Greenland.

200

Anthropogenic debris in three sympatric seal species of the Western Antarctic Peninsula

Msc. Julieta Cebuhar^1,2, Dr. Javier Negrete^3,4, Dr. Lucas Rodríguez Pirani⁵, Dr. A. Lorena Picone⁵, Dr. Maira Proietti^1,6, Dr. Rosana Romano⁵, Dr. Carlos Della Védova⁵, Dr. Ricardo Casaux⁷, Dr. Eduardo Secchi¹, Dr. Silvina Botta¹

¹Federal University of Rio Grande, Rio Grande, Brazil. ²Programa de Pós-Graduação em Oceanografia Biológica, Rio Grande, Brazil. ³Instituto Antártico Argentino, Buenos Aires, Argentina. ⁴Consejo Nacional de Investigaciones Científicas Y Técnicas (CONICET), Buenos Aires, Argentina. ⁵CEQUINOR (UNLP, CCT-CONICET La Plata, associated with CIC), Buenos Aires, Argentina. ⁶The Ocean Cleanup, Rotterdam, Netherlands. ⁷Centro de Investigación Esquel de Montaña y Estepa Patagónica (CIEMEP), Esquel, Argentina

Abstract

Litter pollution is a growing concern, including for Antarctica and the species that inhabit this ecosystem. In this study, we investigated the microplastic contamination in three seal species that inhabit the Western Antarctic Peninsula: crabeater (Lobodon carcinophaga), leopard (Hydrurga leptonyx) and Weddell (Leptonychotes weddellii) seals. Given the worldwide ubiquity of this type of contaminant, including the Southern Ocean, we hypothesized that the three seal species would present anthropogenic debris in their feces. We examined 29 scat samples of crabeater (n = 5), leopard (n = 13) and Weddell (n = 11) seals. The chemical composition of the items found were identified using micro-Raman and micro-FTIR spectroscopies. All the samples of the three species presented anthropic particles (frequency of occurrence - %FO – 100 %). Fibers were the predominant debris, but fragments and filaments were also present. Particles smaller than 5 mm (micro debris) were predominant in all the samples. Leopard seals ingested significantly larger micro-debris in comparison with the other seal species. The dominant color was black followed by blue and white. Micro-Raman and micro-FTIR Spectroscopies revealed the presence of different anthropogenic pigments such as reactive blue 238, Indigo 3600 and copper phthalocyanine (blue and green). Carbon black was also detected in the samples, as well as plastic polymers such as polystyrene, polyester and polyethylene terephthalate (PET), polyamide, polypropylene and polyurethane These results confirm the presence of anthropogenic contamination in Antarctic seals and highlight the need for actions to mitigate the effects and reduce the contribution of debris in the Antarctic ecosystem.

203

Excitation and propagation of magnetosonic waves in the Earth’s magnetosphere: 3D PIC simulation

Dr. Jicheng Sun

Polar Research Institute of China, Shanghai, China

Abstract

Magnetosonic (MS) waves, also referred to as equatorial noise, are common electromagnetic waves in the Earth’s inner magnetosphere. The self-consistent excitation of MS waves has been studied by 2D particle-in-cell simulations in the meridian and equatorial plane of a dipole magnetic field. However, the 3D simulation of MS waves needs to be investigated since the previous 2D simulations artificially limit the direction of wave propagation. Here, we report the excitation and evolution of MS waves in the Earth’s dipole magnetic field based on a 3D general curvilinear particle-in-cell simulation. We find that the MS waves are excited near the equator and primarily confined at 3° of the equator. These waves propagate along both radial and azimuthal directions nearly perpendicular to the background magnetic field. In the linear stage, the growth rates of MS waves are almost equal in radial and azimuthal directions. The waves propagating along the azimuthal direction can grow for a longer time, resulting in the wave amplification dominated by the azimuthal direction after saturation. The simulation results provide a valuable insight to understand the self-consistent evolution of MS waves in the dipole magnetic field, and the findings are useful for understanding the plasma wave-particle interaction in the Earth’s radiation belts.

204

Genetic structure between geographically distant marine fish Macrourus holotrachys and M. berglax

Dr Tshoanelo Miya, Mr Nkululeko Zuma

University of KwaZulu Natal, Durban, South Africa

Abstract

The taxonomic status of Macrourus species has been in disarray due to their morphological similarities and overlapping distribution. Given the number of researches that have been conducted in an attempt to solve the confusion in this group, there are still some species with unconfirmed taxonomy. Macrourus holotrachys found in the Southern Ocean and M. berglax from the North Atlantic Ocean, are among the species that need taxonomic review. These species differ slightly morphologically, and these minor differences have been used as a base to separate them into different species. Molecular studies that have reviewed the taxonomy of these species using the cytochrome c oxidase subunit I (COI) gene found low sequence divergence between M. holotrachys and M. berglax. The findings of these studies exposed a need for population studies to compare genetic structure between these distantly distributed species. The present study aimed to close this gap by assessing the genetic structure between these species using the COI and displacement loop (D-loop) gene regions. For D-loop analyses, there were no shared haplotypes between these species with a single mutation step between their haplotypes. Also, the pairwise Fst value between them was high, 0.711, with a genetic distance of 0.24%. These results indicate that there is a high level of genetic differentiation between M. holotrachys and M. berglax. The COI dataset, on the other hand, had shared haplotypes between these species with low Fst value of 0.070 and genetic distance of 0.13%, indication low levels of differentiation. The difference between the results of the two markers is not surprising as these genes evolve at different paces. Therefore, a third marker is been added for this study and their results will be presented.

206

Late Pleistocene - Holocene paleogeographic reconstruction of the Drygalski Basin (Western Ross Sea) through morpho-bathymetric, isopach, and reflectivity maps from multiscale echographic and seismic reflection dataset

Dr. Martina Tenti¹, Dr. Luca Gasperini², Dr. Maria Cristina Salvatore³, Dr. Carlo Baroni³

¹Ca' Foscari University of Venice, Venice, Italy. ²Institute of Marine Sciences, Bologna, Italy. ³University of Pisa, Pisa, Italy

Abstract

Based on a compilation of morpho-bathymetric and seismic reflection data, we attempted to reconstruct the Late Pleistocene-Holocene glacial evolution of the Drygalski Basin in the Western Ross Sea. This is a key area to understand the past behaviour of the East Antarctic Ice Sheet, close to the present-day coastline, leading us to assume that it could be a privileged observation point to record the latest sequence of post-Last Glacial Maximum (LGM) retreat and re-advance. Our data suggest a “spotty” distribution of the glaciomarine deposits associated to this interval, laying on extended and pervasive erosional surfaces formed after the LGM glacial advance. The compiled isopach map revealed the thickness variability of grounding zone wedges (GZWs), in fact, thicker wedges are located along the flanks of the basin and thinner ones were detected along the trough. Particularly significant are the GZWs detected on the western flank of the basin by analysing morpho-bathymetric data: a thinner one (about 20 m) is overlapped on a thicker one (about 145 m). According to our reconstruction, the Antarctic Ice Sheet (AIS) initially retreated from the LGM location almost reaching the coastline, to then re-advancing depositing the thicker GZW and eventually retreating landward, leaving on the seafloor small-scale GZWs and triggering the inland deglaciation. Evidence for that was found in the thinner GZW detected by the analysis of sub-bottom profiles collected for this study, providing significant evidence that support our reconstruction.

209

Geoheritage and Geoconservation SCAR Expert Group - Update

Dr. Anne Grunow¹, Dr. Enrique Diaz-Martinez², Dr. Cliff Atkins³

¹Ohio State University, Columbus, USA. ²Instituto Geológico y Minero de España, Madrid, Spain. ³Victoria University, Wellington, New Zealand

Abstract

The Expert Group on Geological Heritage and Geoconservation (EG-GEOCON) aims to advance the identification of Antarctic geological sites of exceptional value to be designated geological heritage of international relevance (IUGS Geological Heritage Sites (GHS)), and to contribute to SCAR advice to the CEP and the ATCM on matters related to conservation of geological heritage. The preceding Action Group established the methodology and identified nine geological Frameworks. To date, one Antarctic geosite (K/Pg transition at Seymour/Marambio Island) has been accepted as one of the 1^st 100 IUGS GHS. Furthermore, the Expert Group decided to focus on the following three Antarctic Geological Frameworks (GF) in 2023/2024, respecting the methodology approved and already partially developed by the former Action Group.

GF 1 (Archean cratons): There are several representative sites with unique characteristics. Six sites have been nominated to date.
GF 6 (Cenozoic glacial history): Important glacial history sites are being negatively impacted by frequent science and tourist access. We recognize that this is a broad topic that may have multiple facets and will require a longer discussion. Nine sites have been nominated to date.
GF 7 (Meteorites and evidence of impacts): There are limited geographic occurrences of meteorite fields that are critical in understanding the formation of our solar system. Three sites have been nominated to date.

The SCAR EG-GEOCON is also working to update and expand the list of facilities with Antarctic geological collections. Our goal is to provide links on the SCAR EG-GEOCON webpage to inform scientists about the scope of Antarctic holdings, to encourage finding and utilizing these collections and to promote collaboration between facilities. An updated list of facilities will be given at the SCAR OSC meeting.

The Expert Group has an ongoing workplan and contributions from the wider Antarctic geoscience community are encouraged and welcomed.

211

The Polar Rock Repository: an invaluable resource for Antarctic Ice Sheet studies

Dr. Anne Grunow, Dr. Jamey Stutz, Dr. Erica Maletic

Ohio State University, Columbus, USA

Abstract

The Polar Rock Repository (PRR) contains sample collections and media that are relevant to understanding changes in the Antarctic Ice Sheet. By making terrestrial and marine geological materials available to the cryosphere community, the PRR represents an invaluable resource to help answer key questions involving ice sheet-ocean interactions and the processes affecting glacial retreat.

The PRR (prr.osu.edu) is a National Science Foundation funded facility that provides online access to >61,000 rock samples, glacial deposits, terrestrial drill cores, and dredge samples from Antarctica and surrounding regions. PRR samples can be ordered from the website for research.

The PRR has also created a media archive of >6000 images (with some dating back >60 years) that can provide glaciological, geological, and logistical information as well as provide a record of temporal change associated with surface features (snow cover, ponds, icebergs, streams, etc.).

The PRR website provides multi-field searchable criteria including finding:

Subglacial precipitates
Pedogenic calcite – weathering salts
Coral/marine invertebrates and plants on dredge clasts
Lichen, moss, and soil residues
Fe-Mn nodules and crusts
Fe-oxide surface coatings
Glacial surface features
Glacial erratics
Media of outcrops and landscapes

Antarctic Ice Sheet questions being addressed using PRR samples/metadata include:

Millennial scale climate cycles in the East Antarctic ice sheet since the Pleistocene have been documented using U-series methods on subglacial precipitates.
Provenance studies suggesting early Neogene sea-level oscillations can be from a large West Antarctic Ice Sheet.
Paleotemperature proxies from dredge samples in the Ross Sea and Southern Ocean.
Landscape evolution studies related to onset of glaciation.
Timing of glacial reconstructions using cosmogenic nuclides and optically stimulated luminescence studies.
Studies on CO2 fluxing and magma transport using volcanic rocks from Mt. Erebus.
Use of Fe-Mn nodules to assess influxes from the Antarctic Ice Sheet

214

Dated radar-stratigraphy between Dome A and South Pole, East Antarctica: old ice potential and ice sheet history.

Miss Rebecca Sanderson¹, Dr Neil Ross¹, Dr Kate Winter², Dr Robert Bingham³, Dr S Louise Callard¹, Dr Tom Jordan⁴, Dr Duncan Young⁵

¹Newcastle University, NEWCASTLE UPON TYNE, United Kingdom. ²Northumbria University, NEWCASTLE UPON TYNE, United Kingdom. ³University of Edinburgh, Edinburgh, United Kingdom. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵University of Texas at Austin, Austin, USA

Abstract

An array of information about the Antarctic ice sheet can be extracted from ice-sheet internal architecture imaged by airborne ice-penetrating radar surveys. We identify, trace and date three key internal reflection horizons (IRHs) across multiple radar surveys from South Pole to Dome A, East Antarctica. Ages of ~38 ± 2.2, ~90 ± 3.6 and ~162 ± 6.7 ka are assigned to the three IRHs, with verification of the upper IRH age from the South Pole ice core. The resultant englacial stratigraphy is used to identify the locations of the oldest ice, specifically in the upper Byrd Glacier catchment and the Gamburtsev Subglacial Mountains. The distinct glaciological conditions of the Gamburtsev Mountains, including slower ice flow, low geothermal heat flux and frozen base, make it the more likely to host the oldest ice. We also observe a distinct drawdown of IRH geometry around South Pole, indicative of melting from enhanced geothermal heat flux and/or the removal of deeper, older ice under a previous faster ice flow regime. Our traced IRHs underpin the wider objective to develop a continental-scale database of IRHs which will constrain and validate future ice-sheet modelling and the history of the Antarctic ice sheet.

216

The effects of permafrost degradation on stream geochemistry in the McMurdo Dry Valleys

Anna Wright, Dr. Michael Gooseff, Kathleen Welch

University of Colorado, Boulder, USA

Abstract

The McMurdo Dry Valleys (MDV), Antarctica’s largest ice-free area, contain ephemeral streams that support extensive algal mat growth in the austral summers. Lacking terrestrial vegetation, the physical stream channels consist of rock and soil that is underlain by dry permafrost. In January 2012, there was substantial permafrost degradation which caused channel erosion on the west branch of Crescent Stream, while the east branch remained unaffected. Stream water chemistry samples have been taken weekly each summer in Crescent Stream, below the confluence of the two branches, since 1993 as part of the MCM LTER. In the summers of 2021-2022 and 2022-2023 stream chemistry samples were also taken in the west and east branches, above the confluence and below the permafrost degradation. We used a Welch’s t-test to assess the difference in geochemistry of each branch as well as in the main branch before and after the 2012 degradation. We found that the concentration of major ions ( Cl^-, F⁺, K⁺, Mg²⁺, Na⁺, and SO₄^2-), along with nutrients (inorganic Nitrogen and soluble reactive phosphorous) was significantly higher in the west branch than the unaffected east branch. Along with this, the average concentration of most major ions ( Cl^-, K⁺, Mg²⁺, Na⁺, and SO₄^2-) as well as inorganic nitrogen and soluble reactive phosphorous is significantly greater in Crescent Stream after the 2012 degradation than before. These results suggest that lateral permafrost degradation along stream channels may considerably alter stream water chemistry and increase solute loads to streams and lakes in the MDV, with implications for the downstream ecosystems. As this region has been identified to be nearing a threshold of rapid change, permafrost degradation along MDV streams may have lasting impacts on aquatic ecosystems by affecting algal mat growth and nutrient cycling within the stream channels and downstream lakes.

217

Landscape mapping informing Antarctic Specially Protected Area management

Dr Steph McLennan^1,2, Dr Jodie Smith^1,2

¹Geoscience Australia, Canberra, Australia. ²Securing Antarctica’s Environmental Future, Clayton, Australia

Abstract

Antarctic Specially Protected Area (ASPA) No. 143 Marine Plain in East Antarctica is valued for its “outstanding fossil fauna and rare geological features” (ATCM XXXVI 2013) but scientific evidence to guide its protection is sparse. The fragile Sørsdal Formation contains diverse marine vertebrate and invertebrate fauna, preserving a unique record of Antarctic environmental conditions in the Pliocene (Quilty et al. 2000). Strict permitting and access conditions are in place for the ASPA but evidence-based guidance for decision makers on how to assess the risks to the values of the ASPA is minimal.

We will present the results of geological mapping, aerial imagery collection, and field observations from Marine Plain to consider the impact of foot traffic and helicopter access to the ASPA and provide options for future monitoring and management. Surficial geology of the broader Vestfold Hills (a 400 km2 ice-free region in East Antarctica) was mapped at 1:2000 scale using aerial photos, satellite imagery, a digital elevation model, and field observations (McLennan et al. 2021, McLennan et al. 2022). From this regional-scale mapping, we show that the glacial sediments draping bedrock hills in Marine Plain are typical of the Vestfold Hills region and do not represent the vulnerable Sørsdal Formation or the thermokarst features considered unique to the ASPA. Polygons outlining recommended landing areas for helicopters in the Marine Plain ASPA were derived using a buffer around the Sørsdal Formation, lakes, away from the edge of steep bedrock slopes, and higher that the limit of Pliocene marine inundation. Our results show how foundational datasets like landform and geomorphology mapping can provide robust evidence to support informed ASPA management.

223

Radio-stratigraphy of the Amundsen - Weddell Sea Ice divide: synchronising the WAISD-2014 ice core with englacial layers.

Dr. Felipe Napoleoni¹, Prof. Neil Ross², Prof. Stewart S.R. Jamieson³, Prof. Michael J. Bentley³, Mr. Jonathan Oberreuted⁴, Mr. Jose A. Uribe⁴, Mr Rodrigo Zamora⁴, Prof. Kennichi Matsuaoka⁵, Prof. Robert G. Bingham¹, Prof. Andres Rivera⁶

¹University of Edinburgh, Edinburgh, United Kingdom. ²Newcastle University, Newcastle, United Kingdom. ³Durham University, Durham, United Kingdom. ⁴Centro de Estudios Cientificos, Valdivia, Chile. ⁵Norwegian Polar Institute, Tromso, Norway. ⁶Universidad de Chile, Santiago, Chile

Abstract

Numerical models play a pivotal role in comprehending the dynamics of ice sheet flow, especially in the context of Antarctic ice streams cascading from elevated continental regions to the ice sheet's periphery. These models aid in projecting the potential contributions of specific ice streams to sea-level rise. Nevertheless, significant variabilities in these projections arise due to potential omissions of crucial processes in the numerical models. To mitigate uncertainties, a crucial approach involves contrasting model outputs with observations, thereby replicating past conditions and improving the accuracy of sea-level rise projections. This presentation focuses on the recently mapped englacial structure in a key region of West Antarctica—the Amundsen–Weddell ice divide. This area encompasses the upper reaches of Rutford and Institute Ice Streams, as well as Pine Island Glaciers. Beyond its immediate relevance, this region holds broader significance for glaciologists, as it is believed to be a grounding seed for the early glaciation of West Antarctica. In this talk, we examine the synchronization of dated englacial layers from the WAISD-2014 ice core with this new englacial stratigraphy. This synchronisation helps constrain the age of the ice, providing crucial insights. Additionally, we bridge the gap between the Amundsen and Weddell Sea embayment by presenting two continuously mapped englacial layers from other regions across West Antarctica, contributing to the international effort Antarchitecture.

225

Genetic diversity of the brooding sea star Granaster nutrix (Studer, 1885) in Fildes Bay (King George Island, Antarctic Peninsula)

Jorge Polanco^1,2, Angie Díaz^1,2

¹Universidad de Concepción, Concepción, Chile. ²Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Santiago, Chile

Abstract

In Antarctic marine invertebrates, phylogeographic studies are key to understanding the role of climate history in the configuration of the current biota and its ecological and evolutionary implications. Actually, sea stars (Asteroidea) are the second most diverse group of echinoderms, where its representatives have two reproductive strategies: broadcasting (pelagic larvae) and brooding (parental care). The brooders are characterized by low dispersion and high structure. Although phylogeographic studies are available on Antarctic brooding asteroids, they have not yet been addressed in Granaster nutrix, which is why this study seeks to understand and determine the genetic diversity of G. nutrix in Fildes Bay, King George Island. It is expected that the sampling localities of G. nutrix will present a high structure due to their reproductive strategy. To test the hypothesis, COI mDNA from two locations in Fildes Bay was analyzed. The results show that the individuals in Fildes Bay have low genetic diversity, absence of genetic structure and evidence of recent demographic expansion probably associated with a bottleneck event, which is why the hypothesis is rejected. Further studies are suggested that include more localities representative of the distribution of G. nutrix, both from King George Island and another regions of their distribution, as well as the inclusion of nuclear DNA analyzes to clarify the evolutionary and demographic history of the species.

230

Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica)

Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Edgardo Hernández¹, Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Jose Luis Lopez², Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Lucas A. Ruberto³, Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Marieke Krikke⁴, Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Anouk Piquet⁴, Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Anita Buma⁴, Variability of marine microeukaryotes community during summer at Potter Cove (Antarctica) Walter Mac Cormack¹

¹Instituto Antartico Argentino. Instituto NANOBIOTEC, C0NICET-UBA, Buenos Aires, Argentina. ²Fcultad de Farmacia y Bioquimica, UBA, Buenos Aires, Argentina. ³Instituto Antartico Argentino. Instituto NANOBIOTEC, CONICET-UBA, Buenos Aires, Argentina. ⁴Department of Ocean Ecosystems, ESRIG, University of Groningen, Groningen, Netherlands

Abstract

Potter Cove (25 de Mayo/King George Island, Antarctica) is situated in the northern section of the Western Antarctic Peninsula region. There, environmental conditions show high seasonal variability, related, for example to sea ice cover and glacier meltwater input. These factors may regulate irradiance regimes and nutrient input, thereby governing phytoplankton growth and its community composition. In the present study, we analysed the microeukaryotes succession over one summer season, applying Denaturing gradient gel electrophoresis (DGGE), clone libraries, and 18SrRNA gene sequencing, based on a set of primer for (general) eukaryotes, diatoms, and dinoflagellates. Temperature, salinity, stratification, turbidity, and nutrients were also measured to determine the importance of these environmental drivers for microeukaryotes performance. Different areas of the cove were sampled. Samples from the inner part were found to be highly influenced by glacier meltwater input during summer. DGGE fingerprints cluster analyses of eukaryote, diatom, and dinoflagellate showed different clustering patterns, yet for all groups, Time the main shaping factor. Moreover, one of the glacier-influenced samples clustered separately from others taken on the same sampling day, coinciding with a low salinity and high turbidity event. In addition, diatom and dinoflagellate-specific fingerprints revealed a separate cluster for surface waters. The sequence analysis showed high abundances of Alveolata and Haptophytes (Pheocystis). Overall Potter Cove seems to host a dynamic microeukaryotes community exposed to high temporal variability and some glacier influence.

231

A Latin American collaboration to create a collection of children's books about Antarctica

PhD Sandra Freiberger-Affonso¹, Alfredo Soto², Tamara Sandra Culleton³, Raquel Silvetti⁴, Waldemar Fontes⁵, PhD Flavia SantAnna Rios⁶, PhD Sílvia Dotta¹

¹Federal University of ABC, Santo André, Brazil. ²University of Magallanes, Punta Arenas, Chile. ³National Universit of Mar del Plata, Mar del Plata, Argentina. ⁴National Library of Uruguay, Montevideo, Uruguay. ⁵Asociación Civil Antarkos, Montevideo, Uruguay. ⁶Federal University of Parana, Curitiba, Brazil

Abstract

This work is part of a proposal promoted since 2020 by Antarctic educators from Chile, Uruguay, Argentina and Brazil gathered in the Antarctic Education Forum, an event held since 2016 together with the Meeting of Latin American Antarctic Historians. Since then, a network of projects developed by education professionals interested in bringing the “Antarctic spirit” to classrooms has been consolidated. The main objective is to create and make available educational materials, from which teachers from the aforementioned countries contribute to the construction and consolidation of Antarctic imaginaries from the beginning of their school education. Classrooms are considered fundamental spaces in building the foundations of the Antarctic imaginaries of future generations. On the other hand, during school education, a significant Antarctic experience must be promoted in such a way that it is there where future scientists and citizens committed to the Antarctic legacy of the region are developed. Each story allows us to approach Antarctic themes from different starting points. They respond to the particularities of the historical trajectories of each country and the context in which the Antarctic issue is inserted within the educational systems. It is considered that the possibility of imagining this continent, generally unknown and absent in school curriculum and in pedagogical proposals, is the best way to generate an approach to these remote latitudes. Furthermore, it allows each story to be approached based on the particularities of the classrooms, the interests of each group and also the Antarctic historical and scientific heritage of each country. In this way, the aim is to generate an “Antarctic pedagogical experience” that builds bridges between students, teachers and countries, and thus consolidate in the long term a Latin American view towards Antarctica.

232

Antarctic Freeze-Thaw Dynamics: Characterization of Antifreeze Protein (AFP)-Producing Microorganisms Isolated from King George Island

J. C. Lopes¹, A. M. C. LUIZ¹, C. T. KINASZ¹, V. P. VEIGA¹, B. SEMINIUK¹, L. O. F. SANTOS¹, C. A. FERNANDES¹, V. H. PELLIZARI², R. T. D DUARTE¹

¹Federal University of Santa Catarina, Florianópolis/SC, Brazil. ²University of São Paulo, São Paulo - SP, Brazil

Abstract

The unique environmental conditions of Antarctica, characterized by temperature fluctuations and prolonged freezing periods, have shaped the evolution of microorganisms with remarkable survival strategies. These resilient organisms have developed various adaptations to thrive in such extreme cold environments, enduring the absence of liquid water and exhibiting resistance to freezing through the production of water-binding molecules like antifreeze proteins (AFP). These proteins play a crucial role in modifying ice structure, reducing the freezing point, and preventing recrystallization.This study aimed to identify and characterize microorganisms isolated from diverse Antarctic environments based on their resistance to subzero temperatures and potential antifreeze adaptive mechanisms. Samples were collected from soil, moss, permafrost, and marine sediment on King George Island, situated near the Antarctic Peninsula. Box PCR analysis revealed distinct phylotypes among microorganisms isolated from these different Antarctic environments. A total of 215 microorganisms were isolated, with 118 sequenced and molecularly identified using 16S rRNA and the ITS region. Twenty-four isolates exhibited resistance to freezing at temperatures as low as -18 °C, including 2 yeasts and 22 bacteria. Furthermore, 131 protein extracts were tested for ice recrystallization inhibition (IR), identifying 14 isolates with positive AFP production. Notably, four isolates demonstrated both freeze-resistance and IR activity (Arthrobacter sp. BGS04, Pseudomonas sp. BGS05, Cryobacterium sp. P64, and Acinetobacter sp. M1_25C). This study underscores the diversity of Antarctic microorganisms capable of surviving freezing conditions and emphasizes the importance of further exploring their antifreeze potential for potential biotechnological applications in the future.

233

Interhemispheric Coupling Study by Observations and Modelling (ICSOM)

Dr. Kaoru Sato¹, Dr. Yoshihiro Tomikawa², Dr. Masashi Kohma¹, Dr. Ryosuke Yasui³, Dr. Dai Koshin¹, Ms. Haruka Okui¹, Dr. Shingo Watanabe⁴, Dr. Kazuyuki Miyazaki⁵, Dr. Masaki Tsutsumi², Dr. Damian Murphy⁶, Dr. Chris Meek⁷, Dr. Yufang Tian⁸, Dr. Manfred Ern⁹, Dr. Gerd Baumgarten¹⁰, Dr. Jorge L. Chau¹⁰, Dr. Xinzhao Chu¹¹, Dr. Richard Collins¹², Dr. Patrick J. Espy¹³, Dr. Hiroyuki Hashiguchi¹⁴, Dr. Andrew J. Kavanagh¹⁵, Dr. Ralph Latteck¹⁰, Dr. Franz-Josef Lübken¹⁰, Dr. Marco Milla¹⁶, Dr. Satonori Nozawa¹⁷, Dr. Yasunobu Ogawa², Dr. Kazuo Shiokawa¹⁷, Dr. M. Joan Alexander¹⁸, Dr. Takuji Nakamura², Dr. William E. Ward¹⁹

¹The University of Tokyo, Tokyo, Japan. ²National Institute of Polar Research, Tachikawa, Japan. ³Meteorological Research Institute, Tsukuba, Japan. ⁴Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan. ⁵Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA. ⁶Australian Antarctic Division, Kingston, Australia. ⁷University of Saskatchewan, Saskatoon, Canada. ⁸Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China. ⁹Institut für Energie- und Klimaforschung–Stratosphäre (IEK–7), Forschungszentrum Jülich, Jülich, Germany. ¹⁰Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany. ¹¹University of Colorado Boulder, Boulder, USA. ¹²University of Alaska Fairbanks, Fairbanks, USA. ¹³The Norwegian University of Science and Technology and Birkeland Centre for Space Science, Trondheim, Norway. ¹⁴Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan. ¹⁵British Antarctic Survey, Cambridge, United Kingdom. ¹⁶Pontificia Universidad Catolica del Peru, Lima, Peru. ¹⁷Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan. ¹⁸NorthWest Research Associates, Boulder Office, Boulder, USA. ¹⁹University of New Brunswick, Fredericton, Canada

Abstract

An international joint research project, entitled Interhemispheric Coupling Study by Observations and Modelling (ICSOM), is ongoing. In the late 2000s, an interesting form of interhemispheric coupling (IHC) was discovered: when warming occurs in the winter polar stratosphere, the upper mesosphere in the summer hemisphere also becomes warmer with a time lag of days. This IHC phenomenon is considered to be a coupling through processes in the middle atmosphere (i.e., stratosphere, mesosphere, and lower thermosphere). Several plausible mechanisms have been proposed so far, but they are still controversial. This is mainly because of the difficulty in observing and simulating gravity waves (GWs) at small scales, despite the important role they are known to play in middle atmosphere dynamics. In this project, by networking sparsely but globally distributed radars, mesospheric GWs have been simultaneously observed in seven boreal winters since 2015/16. We have succeeded in capturing five stratospheric sudden warming events and two polar vortex intensification events. This project also includes the development of a new data assimilation system to generate long-term reanalysis data for the whole middle atmosphere, and simulations by a state-of-the-art GW-permitting general circulation model using the reanalysis data as initial values. By analyzing data from these observations, data assimilation, and model simulation, comprehensive studies to investigate the mechanism of IHC are planned. This presentation provides an overview of ICSOM, but even initial results suggest that not only GWs but also large-scale waves are important for the mechanism of the IHC.

234

Increased warming of the sub-Antarctic islands in the 21^st Century

Prof David Hedding¹, Dr Elizabeth Rudolph², Prof Werner Nel³

¹University of South Africa, Johannesburg, South Africa. ²University of the Free State, Bloemfontein, South Africa. ³University of Fort Hare, Alica, South Africa

Abstract

The sub-Antarctic islands represent ideal sentinels for climate change research in the Southern Hemisphere. These islands are located close to the Antarctic Polar Front, with air temperatures that are consistently cool and with annual and seasonal variability buffered by the surrounding cold ocean. This oceanic setting makes them extremely sensitive to shifts in climate. The islands that constitute the 'core' of the sub-Antarctic region are South Georgia, Marion and Prince Edward islands, the archipelagos of Crozet and Kerguelen, Heard and McDonald islands and Macquarie Island. Climatic records from these islands display a considerable warming trend throughout the mid- to late 20^th Century; with numerous reports of drastic landscape and ecological responses. However, has the documented warming trend continued into the 21^st Century? Here we evaluate Mean Annual Air Temperature (MAAT) for the sub-Antarctic islands from 1950-2020 to assess the current state of climate change and highlight potential impacts. For comparison, the MAAT for the “sub-Antarctic” islands of Campbell and Auckland are also analysed. As expected, the warming trend established during the 20^th Century is continuing into the 21^st Century, but the recent (2000-2021) trend of warming is higher than the long-term trend. From linear extrapolation of the long-term trends up to 2000, the predicted MAAT in 2050 is 5.3°C at Macquarie, 5.9°C at Kerguelen and 6.7°C at Marion Island. However, from the rate measured since 2000, MAAT in the middle of the century (2050) is predicted to be 6°C at Macquarie, 6.3°C at Kerguelen and 7.2°C at Marion Island. Importantly, these measured (and extrapolated) warming trends in MAAT at the sub-Antarctic islands are impacting landscape and ecosystem processes on the islands. Moreover, under an increasingly warming climate, the risks posed by invasive species to the ecology of the sub-Antarctic islands is predicted to intensify.

236

New Antarctic Gravity Map based on international data available in the public domain

Mr Alexander Golynsky, Mr Dmitry Golynsky

VNIIOkeangeologia, St.Petersburg, Russian Federation

Abstract

Gravity surveying plays a critical role in the investigation of Antarctica and our understanding of its role in global systems. A substantial amount of ground-based, airborne, and shipborne gravity campaigns have been completed by multinational efforts since the IGY-1958, when the Gamburtsev Mountains were discovered. Over the years, advancements in technology have significantly improved progress in understanding Antarctica. Enhanced navigation and stabilization systems have led to a shift in data collection methods from ground-based measurements to extensive airborne campaigns using specialized ski equipped aircrafts and multiple instruments. Since gravity data has been collected over many decades, it was necessary to find the optimal ways to relevel the survey lines and filter various kinds of noise that arise during the surveying process. The results from the most recent compilation of Antarctic gravity data (Scheinert et al., 2016) were used only for specific regions of Dronning Maud Land where initial profile data was unavailable to us. The only effective means of merging the available anomaly grids for individual surveys was to reprocess and relevel the survey lines. The beginning of each survey processing differed, owing to some surveys had already been processed to an advanced stage while others were provided in their raw form. The beginning of processing differed as some surveys had already been processed to an advanced stage, while others were provided in their unprocessed form. The resulted 5-km grid of gravity anomalies includes rather heterogeneous data distributions with variable line spacings. The use of gravity data in conjunction with magnetic has been crucial in uncovering the complex subglacial geology and deciphering the impact of subglacial sediments and heat flow on the ice sheet stability. Utilizing airborne gravity surveys has been instrumental in mapping the underwater topography beneath major ice shelves, ice-filled fjords, and subglacial lakes.

237

Post ADMAP-2 surveys – on the road towards the ADMAP-3 compilation

Mr Alexander Golynsky¹, Mr Dmitry Golynsky¹, Graeme Eagles², Rene Forsberg³, Fausto Ferraccioli^4,5, Antonia Ruppel⁶, Alexander Kiselev⁷, Kirsteen Tinto⁸, Jamin Greenbaum⁹, Tom Jordan⁵, Ralph von Frese¹⁰

¹VNIIOkeangeologia, St.Petersburg, Russian Federation. ²Alfred-Wegener-Institut Helmholtz-Zentrum für Polar und Meeresforschung, Bremerhaven, Germany. ³National Space Institute, Technical University of Denmark, Copenhagen, Denmark. ⁴National Institute of Oceanography and Applied Geophysics Borgo Grotta Gigante, Trieste, Italy. ⁵British Antarctic Survey, Cambridge, United Kingdom. ⁶Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Germany. ⁷Polar Marine Geosurvey Expedition, Lomonosov, St.Petersburg, Russian Federation. ⁸Lamont Doherty Earth Observatory, Palisades, NY, USA. ⁹Institute for Geophysics, Jackson School of Geosciences, Austin, TX, USA. ¹⁰School of Earth Sciences, Columbus, OH, USA

Abstract

Since the compilation of ADMAP-2 map in 2017, the international Antarctic geomagnetic community collected more than 745,000 line-km of new air- and shipborne data. Many of these new surveys were completed by national and international programs that also acquired airborne laser altimetry, radio echo sounding, and aerogravity data for comprehensive studies of the ice sheet surface and thickness, and crustal geology. These new data help redefine crustal architecture and tectonic evolution, enhance linkages between Antarctica and formerly adjacent continents. The new aeromagnetic data provide key coverage of the Recovery Basin and the South Pole region, southern Princess Elizabeth Land and the Ross Ice Shelf, and other poorly investigated East Antarctic regions. At the South Pole, the European Space Agency PolarGAP aeromagnetic data allow to identify an irregular cratonic margin and an embayment similar to those formed by late Neoproterozoic rifting along Rodinia’s cratonic margins in Australia and Laurentia. One of the largest datasets (125,800 line-km) was collected by the AWI/BGR in and around Dronning Maud Land. The AWI/BGR aeromagnetic data from the southern and eastern Sør Rondane regions offer further insights on the extents of the Tonian Oceanic Arc Super Terrane. The Russian aeromagnetic surveys over Princess Elizabeth and Queen Mary Lands have imaged the East Antarctic extent of a major Stenian-aged accretionary orogen and provide new constraints on the suture between Indo-Antarctica and Australo-Antarctica. Magnetic anomalies from the ROSETTA–Ice’s survey highlight a major crustal boundary between the rifted edges of East Antarctica, which may extend significantly further west than generally assumed. The CHINARE surveys over southern Princess Elizabeth Land are currently proprietary and cannot yet be combined with the existing publicly available datasets. They may provide the first look at the gross lithology and large-scale structural geology of the central Antarctic plate, which is the keystone for tectonic reconstructions.

238

Aeromagnetic Survey with fixed-wing Unmanned Aerial Vehicle in the Bunger Oasis and Highjump Archipelago (East Antarctica)

Alexander Golynsky¹, German Leitchenkov¹, Dmitry Golynsky¹, Pavel Polozov², Fedor Gutorov², Alexander Simakov², V. Antsev²

¹VNIIOkeangeologia, St.Petersburg, Russian Federation. ²RADAR MMS, St.Petersburg, Russian Federation

Abstract

The Bunger Oasis and Highjump Archipelago have been initially surveyed aeromagnetically during the First Soviet Antarctic Expedition in 1956 and since that time not surveyed in detail. Several recently acquired aerogeophysical profiles by international programs conducted in this region mainly aimed to study the structure of Denman and Scott Glaciers. To fill the gap in the knowledge of the geologically complex Precambrian Province, that holds a critical place in East Antarctica, recording the Mesoproterozoic assembly of Australo-Antarctica in Rodinia and the Neoproterozoic–Cambrian amalgamation of Indo- and Australo-Antarctica in Gondwana, VNIIOkeangeologia and RADAR-MMS carried out high resolution aeromagnetic survey using fixed-wing UAV in the 2023/24 field season. The objective of the aeromagnetic investigations was to contribute magnetic data on major aspect of East Antarctic geology to help re-define crustal architecture and tectonic evolution of the Bunger Oasis and Highjump Archipelago and to enhance linkages between Antarctica and formerly adjacent continents. The survey was accomplished with a profile spacing of 250 m and tie line spacing of 1250 m. It was flown draped at ∼120-150 m above the relief surface. In total, 2800 km of high-quality line data was collected over an area of 610 km². The onboard magnetometric system was equipped with a high-precision two-frequency satellite positioning system for accounting differential corrections using a ground base station in Post Processing Kinematic mode. The data underwent several corrections, including magnetic compensation for the aircraft's maneuvers, de-spiking, application of the International Geomagnetic Reference Field, adjustment for diurnals measured by a temporary base station located at the Bunger Oasis Station and full levelling. We present new map that allows identifying specific magnetic anomaly patterns associated with a Neoarchean basement, a Palaeo–Mesoproterozoic sequence of interlayered orthogneiss–pelite gneisses and migmatitic pelite gneisses and Mesoproterozoic plutonic rocks.

239

Magnetic properties of the Bunger Oasis rocks, East Antarctica

Dmitry Golynsky¹, Michael Egorov², Nikolay Gonzhurov², Vladimir Mandrikov², Alexander Golynsky¹

¹VNIIOkeangeologia, St.Petersburg, Russian Federation. ²Polar Marine Geosurvey Expedition, Lomonosov, St.Petersburg, Russian Federation

Abstract

Magnetic susceptibility data (over 15000 measurements) for all of the available rock types of Bunger Oasis was collected by recent Russian geological investigations. Rock age varies from Neoarchean to Mesoproterozoic. The Neoarchean metamorphic complex can be subdivided into four major litho-structural suites. The Remote suite is dominated by migmatitic pyroxene-bearing schists and melanogneisses, they gave highest susceptibilities of up to 61.3×10^–3SI units. The Apfel suite is characterised by ortho and two-pyroxene orthogneisses of quartz-dioritic composition. The Knox suite is represented by orthopyroxene orthogneisses of plagiogranite-tonalite-granodiorite-granite composition. This suite has two particular samplings: granite-gneisses show modal magnetic susceptibility value of 4.02´10^-3SI, whereas granodiorite-granite and plagiogranite orthogneisses have susceptibility value of 14.1´10^-3SI. The Long suite is composed by two-pyroxene orthogneisses of granosyenite-syenite-monzonite composition. As the whole rocks of the Neoarchean complex excepting Remote suite are characterised as moderately magnetic with modal magnetic susceptibility values of 7.90×10^–3SI for Knox suite; 11.9×10^–3SI for Apfel suite; and 25.7×10^–3SI for Long suite. The Neoarchean-Paleoproterozoic paragneisses of the Southern suite are dominated by migmatitic orthopyroxene-biotite crystalline schists and gneisses with bimodal susceptibility distribution of 7.6×10^–3SI and 41.5×10^–3SI. The Paleoproterozoic Transcription suite is largely composed of variably migmatized orthopyroxene plagiogneisses that show a large variability of susceptibility and have a bimodal distribution of 1.0×10^–3SI and 45.8×10^–3SI units. The Mesoproterozoic metamorphic suites are characterized by various values of magnetic susceptibility. The rocks of Figurnaya suite represented by metapsammitic components are mainly characterized by low magnetic susceptibility of about 0.32´10^-3SI. The Central suite composed predominantly of variably migmatized ortho- and two-pyroxene crystalline schists with moderate magnetic susceptibility of 5.98×10^–3SI. The rocks of the Edisto suite comprise layered migmatites with their protolith being high-alumina crystalline schists and gneisses with susceptibility of 34.3×10^-3SI units, while low/moderate magnetic rocks (0.64×10^–3SI and 5.30×10^–3SI) occur as well.

243

The impact of the scientific communication action 'I protect Antarctica and you?' on Facebook and Instagram

BS Keise Correia Carvalho¹, PhD Silvia Dotta¹, PhD Sandra Freiberger-Affonso¹, PhD Flavia Sant´Anna Rios², PhD Amanda Leal da Silva Teodoro³, MSc Taluany Silva do Nascimento⁴

¹Federal University of ABC, Santo André, Brazil. ²Federal University of Paraná, Curitiba, Brazil. ³Apecs-Brasil, Concórdia, Brazil. ⁴Federal University of Pernambuco, Recife, Brazil

Abstract

This study aims to present the results of scientific communication activities carried out by InterAntar, in collaboration with APECS-Brasil and Ciência Interativa, on Facebook and Instagram, to celebrate Antarctica Day in 2023. The importance of collaboration between different initiatives linked to the subject of Antarctica as it is possible to reach a wider audience that has the same interest, but uses different approaches. An example of this is that on the APECS-Brasil profile the majority of followers are researchers or postgraduate students. InterAntar and Ciência Interativa, on the other hand, reaches many school teachers due to its approach focused on education and teaching, besides the general public. InterAntar profiles have 3,225 followers on Facebook (45.3% men, 54.7% women) and 3,266 on Instagram (36.8% men, 63.1% women). The predominant age group is 35 to 44 years old, with 19.7% women on Instagram, 14.6% on Facebook, 10.7% men on Instagram, and 13.1% on Facebook. During the period from November 17th to December 1st, 2023, the campaign "I protect Antarctica and you?" with posts publications, interactive stories, live broadcasts from the Brazilian Antarctic Station, reels with brazilian scientists in Antarctica. After the action, the results were analyzed quantitatively: on Facebook, 457 people were reached with 209 impressions. On Instagram, was reached 8,424 people, with 4,846 impressions and 6,855 views. Impressions count all views, while viewing is unique per person. Posts on Instagram surpassing Facebook The results suggest that interactions on social media can contribute to disseminating information about polar sciences. However, it is necessary to expand research to more extended periods that allow the comparison of historical series and the obtaining of qualitative data, which allows an understanding of the real impact of these media on science communication.

245

Basal melting effects on water masses production and export around the Antarctic Peninsula

Dr. Luciana Shigihara Lima¹, Michael Dinniman², Dr. Carlos Moffat³, Dr. Mauricio Magalhaes Mata⁴, Dr. Luciano Ponzi Pezzi¹, Dr. Mylene Jaen Cabrera¹, Dr. Celina Ferreira Rodrigues¹, Dr. Marcelo Santini¹, Tiffany Mendonça¹

¹National Institute for Space Research (INPE), Sao Jose dos Campos, Brazil. ²Center for Coastal Physical Oceanography (CCPO/ODU), Norfolk, USA. ³University of Delaware, Delaware, USA. ⁴Federal University of Rio Grande (FURG), Rio Grande, Brazil

Abstract

We investigate the effects of basal melting on circulation, water masses, and sea ice production in the ocean surrounding the Antarctic Peninsula (Bellingshausen-BS and Weddell Seas-WS). To do this, we used the Regional Ocean Model System (ROMS) to simulate the dynamic and thermodynamic mechanisms in this region. Control (CTRL) and sensitivity (SENST) experiments were conducted simulating the ocean between 2002 and 2020. In SENST, the salt and heat fluxes representing the freshwater fluxes from melting were set to zero. An increase in sea ice production (average increase of 0.1m in thickness) in the coastal region was observed in CTRL, due to the extremely cold freshwater plumes resulting from ice shelf basal melting. There was also an increase in the production of dense bottom waters fed by the production of the extremely cold Ice Shelf Water from basal melting, and the high-saline and dense waters (HSSW) resulted from the sea ice production. The increase in sea ice concentration (SIC) was also observed in the Weddell Gyre (WG) region in the CTRL, as well as an intensification of the gyre. The surface current intensity was noted, mainly in the WG, caused by changes in wind stress on the ocean, due to changes in sea ice thickness at the surface. Over the BS, the intensification of westerly winds increases the circulation of modified Circumpolar Deep Water into the ice cavities, contributing to changes in ice melting and platform instability. Temporally, changes in wind patterns, sea ice formation and extent, and basal melting patterns are observed after the year 2011 (wavelet analysis). The results can indicate the freshening and warming process that is happening with the Antarctic Bottom Water (AABW). Besides the increase in the production of dense bottom and surface water masses, we verified a greater stratification process in the CTRL experiment.

247

Assessment of microplastic pollution in surface marine sediments of the coastal environment of Potter Cove (25 de Mayo Island/King George Island, South Shetlands, Antarctica) and surrounding areas

Dr. Julieta Antacli^1,2, Dr. Irene Schloss^3,4,5, Dr. Guido Rimondino⁶, Dr. Gastón Alurralde^7,8, Dr. Natalia Servetto^1,2, Dr. Maximiliano Garcia⁹, Biól. Sol Morales¹, Biól. Antonela Ottero¹, Lic. Germán González^1,2, Dr. Rosana Di Mauro¹⁰, Dr. Ricardo Sahade^1,2, Dr. Cristian Vodopivez³

¹Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Ecología Marina, Av. Vélez Sarsfield 299, 5000, Córdoba, Argentina. ²Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ³Instituto Antártico Argentino, 25 de Mayo 1143, San Martín, Buenos Aires, Argentina. ⁴Centro Austral de Investigaciones Científicas (CADIC, CONICET), Bernardo Houssay 200, Ushuaia, Argentina. ⁵Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina. ⁶Instituto de Investigaciones en Físico Química (INFIQC), CONICET, Departamento de Físico-Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina. ⁷Department of Environmental Science, Stockholm University, 10691, Stockholm, Sweden. ⁸Baltic Marine Environment Protection Commission HELCOM, Helsinki FI-00160, Helsinki, Finland. ⁹Agencia de Investigación Científica del Ministerio Público de La Pampa, Corona Martínez y Constituyentes, Santa Rosa, La Pampa, Argentina. ¹⁰Gabinete de Zooplancton, Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Mar del Plata, Argentina

Abstract

The increasing presence of marine plastic pollution raises concerns about the threats it poses to the Southern Ocean and Antarctic ecosystems. Recent findings showed elevated levels of microplastic debris (MPs, particles <5 mm) of <1 mm size in the coastal waters of Potter Cove (King George Island/25 de Mayo, South Shetlands, Antarctica) (Antacli et al. 2024). Here, we present the first comprehensive analysis of MPs' concentration, distribution, and composition in marine sediments surrounding P. Cove. The objective was to characterize and quantify plastics and infer their sources. Extensive samplings were conducted through SCUBA-diving and a stainless-steel Van Veen grab operated from a Zodiac boat during 2020-2021. 31 near-surface sediment samples (15-25 m depth) were collected in Potter Cove and nearby sites, capturing diverse influences from the Argentinian Carlini research station´s activities. MPs were retrieved by flotation, categorized, microscopically photographed, measured using image analysis software (Image J), and identified through FTIR spectroscopy, to ascertain their polymeric composition. Results revealed MPs were present in all samples, with concentrations ranging from 0.02 to 0.80 MPs/g (average: 0.26±0.22 MPs/g). Anthropogenic, transparent, white, and blue microfibers were the dominant type (length range: 0.08 - 7.8 mm; median: 0.01 mm). Additionally, irregular, black, blue, and transparent microfragments (diameter range: 0.04 - 4.9 mm; median: 0.33 mm) were also prevalent. Most MPs exhibited signs of aging, such as discoloration and unraveled features, resembling those commonly associated with clothes washing. The highest MP concentrations were recorded near the wastewater treatment plant outfall of the station, implicating local activities as the primary source. This study underscores the urgent need for further research on MPs around other Antarctic stations to identify potential sources of contamination. Such findings can inform policy discussions and contribute to the development of effective management responses.

248

Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island).

Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island). Agustina Rivas¹, Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island). Natalia Venturini¹, Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island). Noelia Kandratavicius¹, Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island). Pablo Muniz¹, Structure and ecology of meiobenthic communities in an Antartic fjord affected by glacier retreat (Collins Bay, King George Island). Luis Cerpa²

¹Facultad de Ciencias (UdelaR), Montevideo, Uruguay. ²Instituto Geológico, Minero y Metalúrgico (INGEMMET),, Lima, Peru

Abstract

The Antarctic Peninsula has experienced notable warming and glacier retreat in recent years, impacting marine environments and benthic communities. Meiofauna is a useful tool for monitoring climate change effects, and plays an important role in trophic chains and biogeochemical cycles. However, currently knowledge of polar meiofauna remains limited. This study explored Antarctic meiofauna in Collins Bay, King George Island, and its relationship with sediment biogeochemical properties under different glacial influence. Sediment (van Veen grab) and meiofauna (minicorer) samples were collected from three transects onboard the R/V “BAP Carrasco” (Peruvian Navy) in February 2018. Transects 1 (stations 1A-1C) and 2 (2A-2C) were located at 2000 and 3000 meters from Collins Glacier's marine front, respectively, while Transect 3 (3A-3D) was near Artigas Base, affected by glacier meltwater runoff. Sediment granulometry, organic content, and physicochemical variables of bottom water were studied at each sampling station. A total of 58383 individuals grouped into 32 taxa were identified, the most abundant groups were nematodes (81%) and copepods (7.1%). Transect 2 revealed a more diverse and uniform community, indicating lower glacier impact with higher organic content and homogeneous sediments. In contrast, transect 3 showed lower diversity and less uniformity due to meltwater discharge via glacial surface runoff. The highest nematode abundance in transect 3 may be linked to their resilience to environmental disturbances. Analysis of variance indicated significant differences in abundances of cladocerans, tardigrades, ostracods, loriciferans, gastrotrichs, bivalves, and aplacophorans, showing that "rare" taxa are more susceptible to environmental variations. The presence of environmental stress-sensitive groups in transect 1 suggested a low impacted community structure near the glacier marine front compared to the area affected by glacier meltwater runoff. Multiple linear regressions revealed that group abundances primarily responded to differences in organic content (total carbohydrates and total organic carbon) and physicochemical water parameters (temperature and depth).

253

Understanding organic particle behavior in Southern Ocean ecosystems: The significance of benthic-pelagic coupling

Stefanie Martinez¹, Natalia Venturini¹, Luis Cerpa²

¹Sección Oceanografía y Ecología Marina, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Instituto Geológico Minero y Metalúrgico (INGEMMET), Lima, Peru

Abstract

Particulate organic matter (POM) distribution and fate in the Southern Ocean (SO) are the result of sea ice seasonal dynamics, the interaction among primary, secondary and chemoautotrophic production through processes involved in the biological carbon pump at different depths. Seamounts in deep areas of the SO generate intense upward currents that inject nutrients into the euphotic zone stimulating primary production. In contrast, Antarctic coastal fjords have substantially different ecosystem forcing, being very productive due to the drainage of glaciers. This work aimed to assess POM lability using biochemical markers such as organic biopolymers, total proteins (PRT), lipids (LIP) and carbohydrates (CHO) in the water column and in surface sediments of coastal and deep zones in the SO. The stations were located in two coastal fjords Collins Bay (CB) and Hope Bay (HB), and in the Bransfield Strait, near Deception Island (DI) and in The Axe - Little Point (LP) seamount. Sampling was carried out in January 2020 onboard the O/V BAP Carrasco during the ANTAR XXV Peruvian expedition. Although there were no significant differences in biochemical characteristics of suspended POM between fjords, sedimentary values showed high PRT abundances and higher BPC in CB than in HB, indicating a stronger benthic-pelagic coupling in CB. PRT/CHO ratios > 1 and CHO/LIP < 1 indicate high POM lability and energetic value, supporting the occurrence of a benthic-pelagic coupling and the development of a benthic “food bank”. Similar trends were observed in POM biogeochemical features in the Bransfield Strait, with significantly higher suspended LIP concentrations in LP than in DI. Higher sedimentary CHO values, PRT/CHO and CHO/LIP ratios in LP compared to DI indicated a potential “seamount effect” enhancing local primary production. Despite being geomorphologically different, biogeochemical composition of suspended and sedimentary POM reflects an important benthic-pelagic coupling in both zones.

254

The antarctic scientist through the eyes of Brazilian high school students: A case study at CEM 01 Paranoá

The antarctic scientist through the eyes of Brazilian high school students: A case study at CEM 01 Paranoá Iane Perdigão, Micheline Carvalho Silva, Paulo Camara

Universidade de Brasília, Brasília, Brazil

Abstract

Research on perceptions regarding the imagery of scientists has been conducted since the last century. Mead and Meatrux were pioneers in this quest, with a pilot study published in 1957 indicating that for high school students, scientists were merely depicted as men, white, solitary individuals, often clad in lab coats. This perception was further supported by Chambers' studies in 1983. The researcher formulated the DAST protocol, which outlines a series of criteria for identifying the imagery of scientists through drawings created by students of various ages. In the present study, a modified version of the initial DAST protocol was employed, incorporating the use of questionnaires and observations of student behavior during classes. In order to encompass examples of scientists beyond chemists, who are frequently portrayed by the media, the imagery representation of Antarctic scientists was explored. In addition to lab coats and laboratories, students from CEM 01 Paranoá depicted Antarctic scientists as a diverse group, primarily as outdoor researchers. In contrast to past research, this study demonstrated a diverse and representative imagery of gender identities, colors, and races. The inclusion of hybrid analysis allowed students to indicate the existence of non-binary scientists in addition to the female and male genders. Among the analyses of color and race, the presence of white, black, yellow, and indigenous scientists was found. These modifications in the imagery pattern regarding scientists, focusing on Antarctic scientists, indicate a positive change and include socially marginalized groups in the imaginative realm of students in the New Brazilian High School Education.

Key words: Education; antarctic scientist; socially marginalized groups representation

256

Understanding Variability in Warm Deep Water Transport and Its Implications for Antarctic Ice Shelves in the Southwestern Weddell Sea

Marina Noro¹, Dr. Ilana Wainer¹, Dr. Tiago S. Dotto², Dr. Marcos Tonelli³, Dr. Fernanda Marcello¹, Iuri Gorenstein¹

¹University of Sao Paulo, Sao Paulo, Brazil. ²National Oceanography Centre, Southampton, United Kingdom. ³Admiral Paulo Moreira Institute for Sea Studies, Rio de Janeiro, Brazil

Abstract

The Circumpolar Deep Water (CDW) is the main heat source for the Antarctic margins. Its onshore transport influences key processes with global implications, including the melting of Antarctic ice shelves and the process of Antarctic Bottom Water (AABW) formation. Melting ice sheets around Antarctica have significantly contributed to recent sea level rise, representing a major uncertainty in future projections. The observed warming and ice-shelf volume loss in some regions around the Antarctic margins have been directly linked to the inflow of the CDW onto the continental shelf. While no significant trends in the rates of ice loss due to basal melting in the Weddell Sea ice shelves are currently observed, this region has experienced an unprecedented decrease in sea ice since 2016. This decline in sea ice formation makes the ice shelves more vulnerable, potentially leading to an acceleration of basal melting that might have profound impacts on the ice sheet mass loss and dense water formation in this region. In this study, we aim to investigate the variability of Warm Deep Water (WDW), the local variant of CDW, transport in the Weddell Sea ice shelf region and identify periods of potential inflow of warmer waters toward the shelf. To achieve our goal, we rely on high-resolution results from the Global Ocean Physics Reanalysis 1/12° (GLORYS12V1) product provided by the Copernicus Marine Environment Service (CMEMS).

257

AMS AND PETROFABRIC OF JURASSIC VOLCANIC UNITS FROM HOPE BAY (BAHÍA ESPERANZA), ANTARCTIC PENINSULA

Dr. Florencia Milanese¹, Laila Iacono², Dr. Pablo Franceschinis³, Dr. Carla Puigdomenech⁴, Lic. Rodrigo Feo⁵, Lic. Joaquín Gil⁶, Dr. Jorge Lozano³, Miguel Gumina², Dr. Juan Manuel Lirio⁴, Dr. Augusto Rapalini³

¹Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina. ²University of Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias Geológicas, CABA, Argentina. ³Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires, CABA, Argentina. ⁴Instituto Antártico Argentino, Gral. San Martín, Argentina. ⁵Centro de Investigaciones Geológicas, La Plata, Argentina. ⁶Centro de Estudios Integrales de la Dinámica Exógena, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina

Abstract

We present an Anisotropy of Magnetic Susceptibility (AMS) study carried out on paleomagnetic samples from Hope Bay area, including a total of 453 (n=453) specimens coming from twenty-two sites (N=22). Three sites from the twenty-two (N=3) correspond to two tuff levels intercalated in the fossiliferous Middle-Upper Jurassic Mount Flora Formation. After making the tectonic correction, the lower tuff from Mount Flora Formation presents an excellent grouping of the axes of minimum (k3) and maximum (k1) susceptibility in the vertical and WSW-ENE directions, and an oblate anisotropy ellipsoid. This suggests a sedimentary fabric with a WSW-ENE flow direction. The upper tuff shows a much more chaotic fabric, with both prolate and oblate ellipsoids. Eleven sites (N=11) correspond to the volcanic and volcaniclastic units from Upper Jurassic Kenney Glacier Formation. These units also show very well defined groupings of k3 axis, but these groupings present different directions of ?imbrication depending on the sampling site. Anistropy ellipsoids are equally prolate and oblate and a rough grouping of k1 in the WSW-ESE direction is also observed. The remaining eight sites (N=8) correspond to two Cretaceous intrusive bodies and two dykes that outcrop in the surrounding area of Mount Flora, where Jurassic outcrops are concentrated. These ellipsoids are also oblate and prolate but ASM fabrics do not appear to be very well-defined. Bulk magnetic susceptibilities present a wide variation, being mean values between 15E-6 and 2E-3 SI. Lower values correspond to Jurassic rocks. The parameter of anisotropy P does not exceed 1.16 in most cases.

258

Investigating the Impact of the Southern Ocean on Antarctic Sea Ice Variability through a Long Pre-Industrial High-Resolution CESM Simulation to Assess Natural Variability

Dr. ILANA WAINER, Msc MARINA SANTOS, Dr FERNANDA MARCELLO, Msc IURI GORENSTEIN

UNIVERSIDADE DE SAO PAULO, SAO PAULO, Brazil

Abstract

This study aims to examine the influence of Southern Ocean dynamics on Antarctic sea-ice variability by utilizing an unprecedented high-resolution 500-year pre-industrial control climate simulation (PI-CTRL; Chang et al., 2020). The PI-CTRL ocean component was initialized with the January-mean climatological potential temperature and salinity from the World Ocean Atlas (WOA). These simulations provide a stable baseline of the climate system before significant anthropogenic influences, primarily due to greenhouse gas emissions, began altering the climate., This approach enables us to understand the natural variability and inherent dynamics of the Earth's climate system without the noise introduced by human activity. Recognizing the critical role of the Southern Ocean in global climate and sea-level changes, we seek to understand, the complex relationships between ocean circulation — particularly the Circumpolar Deep Water (CDW) transport — and sea-ice concentration and stability in this pre-industrial context. Focusing on the long PI-Control simulation, the research will investigate temperature, salinity, sea-ice concentration, and additional key variables to assess the ocean’s influence on sea-ice conditions. The anticipated findings are expected to contribute to and enhanced understanding of natural variability, providing valuable insights to inform and constrain the potential future states of the Southern Ocean and its implications for global sea-level rise and climate dynamics.

261

Antarctic Groundwater Exfiltration through the Last Deglaciation

Ellie Miller, Dr. Ryan Venturelli

Colorado School of Mines, Golden, USA

Abstract

The investigation of subglacial hydrologic systems beneath the Antarctic Ice Sheet (AIS) has historically focused on the presence of lakes and rivers, but recent endeavors have begun to shed light on the critical role of groundwater. The understanding of groundwater's role in subglacial hydrology remains rudimentary, primarily due to the inaccessibility of the ice-bed interface, contained under several kilometers of ice. Recent work highlights the interplay between ice sheet change and subglacial hydrology, revealing that glacial thinning reduces the mechanical load on sub-ice aquifers. This allows for groundwater to exfiltrate out of the sediment at the ice-bed interface at measurable rates in the modern record. To explore the role of glacial thinning on groundwater exfiltration over geologic timescales, we employ data from the informal cosmogenic-nuclide exposure-age database (ICE-D) to derive deglacial thinning rates across the Antarctic continent from the Last Glacial Maximum (~20,000 kyr) to present. By incorporating these rates into a cutting-edge hydromechanical model (Robel et al., 2023), we calculate groundwater exfiltration rates of the recent past, offering a novel comparison to contemporary records. Our findings elucidate the evolving dynamics of subglacial hydrology over the last 20,000 years, providing insights of how these changes influence ice movement, basal melting, and adjacent marine ecosystems. This research contributes a critical perspective to the understanding of the Antarctic subglacial hydrologic system, highlighting the need for further exploration and assessment of its potential broader impacts.

267

The evolution of Antarctic cultural heritage protection mechanism and its implication for China

Dr. Yanyan Shan

Polar Research Institute of China, Shanghai, China

Abstract

The protection mechanism for Antarctic cultural heritage is established under the leadership of the Antarctic territorial claimants and is implemented under the umbrella of the Antarctic Treaty System. The entry into force of the Madrid Protocol and the Annex V, which are committed to protecting the Antarctic environment, establishes a key system for protecting the historical and cultural values of Antarctica. In order to conduct in-depth analysis on the development of the Antarctic cultural heritage protection and governance mechanism led by the Antarctic territorial claimants, this research first reviews the history of the Antarctic cultural heritage under the Antarctic Treaty System in the past 60 years, and then makes comprehensive analysis of the 95 listed HSMs from four aspects, namely, the geographical coverage, the criteria used for designation, the proposing party/parties and the scope of the period they represent. The results reveal several interesting phenomena along with some problems in the governance of cultural heritage under the Antarctic Treaty System. Finally, based on the two case studies focusing on the regions of the Antarctic Peninsula and the Ross Sea, combined with the new trends under both climate change and geopolitics, this paper explores the implications and feasible path for China to participate in the future governance of Antarctic cultural heritage.

268

Climatic gradient drives soil organic carbon stocks in Antarctica ice free areas and permafrost

Dr. Danilo Mello¹, MSc Cássio Moquedace¹, MSc Clara Baldi¹, Sr. Lucas Silva¹, Sr. Miguel Mendes², Dr. Márcio Francelino¹, Dr. Tiago Ferreira², Dr. José Demattê², Dr. Carlos Schaefer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade de São Paulo, Piracicaba, Brazil

Abstract

The soil organic carbon stocks (SOC stocks) in Antarctic regions and permafrost will be influenced by future climatic conditions, encompassing changes in temperature and precipitation patterns. The comprehension SOC stock dynamic due to changes in climatic variables can unveil areas with greater potential for storing increased amounts of soil organic carbon. In this sense, our objective was to predict and evaluate the dynamics of SOC stocks, considering the climatic gradient in terms of pluviometric precipitation and temperature. In pursuit of this objective, we employed the most extensive soil dataset, which included 3,500 soil samples gathered in the field. Initially, we determined soil bulk density (BD) values and calculate SOC stock by using soil organic carbon content data, BD and soil thickness. Subsequently, we employed climate data (pluviometric precipitation and temperature) from Chelsea at present time, incorporated topographic variables, and applied machine learning techniques in our predictive model. Our results revealed a decrease in SOC stock values as we moved from the edges of the continent towards its interior (ranging from 500 – 1000 Megagrams in Maritime Antarctic to 1 – 500 Megagrams in the Antarctic Peninsula), with the model demonstrating satisfactory performance as indicated by the Lin’s Concordance Correlation Coefficient index (0.52). The observed pattern of SOC stock distribution is attributed to a relationship between SOC stock and both latitude and longitude. Latitude was found to exert a more pronounced influence on temperature, while longitude had a notable impact on pluviometric precipitation. In conclusion, SOC stock levels exhibit a decreasing trend towards the edges of the continent, further diminishing towards its interior. This pattern correlates with decreasing temperature and pluviometric precipitation.

271

Digestive gland transcriptomic and clam oxygen consumption modulations of Laternula elliptica after single and combined exposures to nanoplastics and nanometals

Mr. Rodolfo Rondon¹, Mr. Felipe León¹, Ms. Céline Cosseau², Ms. Elisa Bergami³, Mr. Cristián Chaparro², Mr. César A. Cárdenas^1,4, Ms. Carolina Pérez-Toledo¹, Mr. Ignacio Garrido⁵, Ms. Garance Perrois⁶, Mr. Kurt Paschke^7,5,4, Mr. Erwan Corré⁸, Ms. Ilaria Corsi⁹, Mr. Marcelo González-Aravena¹

¹Departamento Científico, Instituto Antártico Chileno, Punta Arenas, Chile. ²Laboratoire des Interactions Hôtes-Pathogènes-Environnement, CNRS, IFREMER, Université de Montpellier, Université de Perpignan « Via Domitia », Perpignan, France. ³Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 213/D, Modena, Italy. ⁴Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago de Chile, Chile. ⁵Centro de Investigaciones Dinámica de Ecosistemas Marinos de Altas Latitudes, Valdivia, Chile. ⁶Tropical & Subtropical Research Center, Korea Institute of Ocean Science & Technology, Jeju, Korea, Republic of. ⁷Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile. ⁸Faculté de Sciences, CNRS, FR 2424 CNRS, ABIMS, Station Biologique de Roscoff, Université Sorbonne, Roscoff, France. ⁹Department of Physical Science, Earth and Environment, Università di Siena, Siena, Italy

Abstract

Fildes Bay coast is impacted by human activities potentially affecting its marine organisms. Furthermore, some contaminants of emerging concern (CEC) have already been detected. These include nanoplastics and nanometals, which have been found to cause various molecular changes in aquatic metazoans. However, there is limited information available regarding their impact on Antarctic species. In this sense, the present study aimed to assess the digestive gland global transcriptomic and clam oxygen consumption modulations of Laternula elliptica, to nano-polystyrene (n-PS) and nano-titanium-dioxide (n-TiO₂) single and combined exposures at two concentrations (5 and 50 µg/L). A total of 2852 differentially expressed genes were detected considering all treatments compared to controls. Key genes with differential expressions, such as chaperones HSP 40s and their transcription factor HSF, proteases, and fatty acid desaturase (involved in membrane permeability) and the tumor suppressor and response to oxidant stress Tumor protein p53-inducible nuclear protein 1 were revealed. Also, Carbonic anhydrase is potentially implicated in acid-base balance, and genes implicated in energy metabolism (Glycolysis, Krebs cycle and glycogenolysis) as well as genes of transport of ions and nutrients were affected. Intriguingly, Mitochondria-eating protein was induced in some treatments, suggesting mitochondrial stress. Finally, antioxidant and immune gene dysregulation were observed. Oxygen consumption decreased significantly for the combination of pollutants at two concentrations, suggesting that this synergy provoked a diminution of clam metabolism. These results highlighted the molecular toxicity and potential stress for the Antarctic benthos key species L. elliptica, which could be used to monitor populations and ecosystem health.

276

Portugal in Antarctic history

Prof. José Xavier^1,2, Dr Bob Headland³

¹University of Coimbra, MARE-UC, DCV, Coimbra, Portugal. ²British Antarctic Survey, Cambridge, United Kingdom. ³Scott Polar Research Institute, University of Cambridge, Cambridge, United Kingdom

Abstract

Historically, Portugal is associated with the Antarctic region: Fernão de Magalhães (c. 1480-1521) is one of the first explorers mentioned when talking about the beginnings of Antarctica (Terra incognita), by discovering the Southern Hemisphere trade route from the Atlantic Ocean to the Pacific Ocean through the Strait of Magellan (initially named Estreito de Todos os Santos). For the following 500 years little information was known about the presence of Portuguese in the Antarctic region. In the 2000´s, Portugal participated in the International Polar Year 2007-08, considered a succesful example of a recent emerging nation and joined various international organizations, including the Scientific Committee on Antarctic Research (SCAR) in 2006 and acceded to the Antarctic Treaty in 2010, being involved in major research, education and outreach outputs in the last two decades. In this presentation, we aim to show that Portuguese citizens have had centuries of involvement in the Antarctic beginning from early discoveries, from the epoch of navigation and exploration, then during the sealing period during which the continent became known, and in the subsequent whaling decades. Portuguese have been in 10 out of the 19 sub-Antarctic and Antarctic islands (i.e. Ile Amsterdam, Auckland Islands, Ile Crozet, Gough Island, Heard Island, Iles Kerguelen, Macquarie Island, Prince Edward Islands, South Georgia and South Shetland Islands) since the 16th century on discovery, sealing and whaling expeditions). A few reasons contributed to it, including: 1) the discovery of abundant seals during the second voyage of James Cook (1772-75), 2) the commercial value of fur seal (Arctocephalus gazella) pelts and elephant seals (Mirounga leonina) oil and 3) the majority of sealing voyages were from the eastern United States with calls at Portuguese Atlantic Islands (E.g. Azores Islands, Madeira Island) where crew could be recruited.

277

Construction and assesments of knowledge and learning processes: communities of practice, historical routines and artefacts, and intergenerational relations in Antarctica.

Dra. Fabrizio María Laura

Instituto Antártico Argentino, Buenos Aires, Argentina. Instituto de Ciencias Antropológicas - Universidad de Buenos Aires, Buenos Aires, Argentina

Abstract

In this presentation, we ethnographically analyse the modalities of knowledge construction and learning processes that take place among different subjects (scientists, technicians, divers, among others) in Antarctica. Based on the fieldwork carried out at Carlini Station during the 2023/2024 summer season, we examine the processes of knowledge construction, taking into account that learning does not only take place at specific times and places.

From an analytic perspective that reflects on the situated everyday practice, we understand that the everyday process of knowledge construction takes place within a relational framework that provides conditions of possibility for learning, including practices, historical artefacts and routines that can be accumulated and used later.

It is therefore of interest to look at the practices developed by scientists. Most of them are professionals in the natural or related sciences, who form complex and dynamic communities of practice in the work of sampling and developing research projects in Antarctica. Sampling activities involve a range of tasks and techniques, many of which are learned in the field. These include knowledge sharing, routines and use of artefacts based on intergenerational relationships, relationships between different work groups, processes of assesments of variables such as ´Antarctic experience´, the number of research campaigns, and more.

We assume that all activity, including learning, is situated in and consists of relationships between people, contexts and practices. We therefore analyse how these relationships are configured, taking into account the different educational backgrounds and trajectories of the participants in the research campaign and the different roles they have assumed, and taking into account the historical traces of the construction of knowledge in Antarctica.

278

Pushing the boundaries of polar oceanography: New insights from a multi-glider survey on the Ross Sea Continental Shelf

Dr Naomi Krauzig¹, Prof Pierpaolo Falco¹, Prof Gianetta Fusco², Prof Giuseppe Aulicino², Prof Giorgio Budillon², Prof Yuri Cotroneo², Diana Di Luccio², Simone Di Palma², Massimiliano Esposito², Antonino Ian Ferola², Laura Fortunato², Dr Alberto Greco², Angela Garzia³, Prof Elena Mauri⁴, Dr Stefano Kuchler⁴, Dr Alessandro Bubbi⁴, Dr Piero Zuppelli⁴, Dr Julietta Logarzo⁴, Dr Riccardo Martelucci⁴, Dr Christian Saggese⁴, Dr Anunziata Pirro⁴, Prof Pasquale Castagno⁵, Dr Jasmin McInerney⁶, Dr Cassandra Elmer⁶, Dr Craig Stewart⁶, Dr Eleanor Haigh⁶, Prof Craig Stevens⁶

¹Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy. ²Department of Science and Technology, University Parthenope of Naples, Naples, Italy. ³Department of Civil, Constructional and Environmental Engineering, Sapienza University, Rome, Italy. ⁴National Institute of Oceanography and Applied Geophysics (OGS), Trieste, Italy. ⁵Department of Mathematics, Computer Science, Physics and Earth Science, University of Messina, Messina, Italy. ⁶National Institute of Water and Atmospheric Research, Wellington, New Zealand

Abstract

Despite their significant impact on global climate systems, polar oceans remain scarcely observed and insufficiently represented in climate models due to their extreme conditions.

Now, autonomous instruments like underwater gliders offer the possibility to capture even fine-scale variations in these conditions. Recognizing their capabilities and the scientific significance of addressing the mentioned data and knowledge gaps, we deployed three different underwater gliders in January 2024 in strategic sectors of the Ross Sea continental shelf, covering a total of ~760 km. Sampling key polynya areas like Terra Nova Bay and topographically-steered inflow and outflow regions, the gliders provided unprecedented high-resolution physical and bio-geochemical observations. Overall, new insights were gained regarding the spatio-temporal variability of the main water masses, such as High Salinity Shelf Water in its formation and export areas, inflowing Amundsen Sea Water at the eastern gate and Ice Shelf Water flowing out of the Ross Ice Shelf cavity. The characterization of these water masses and their interactions aid, among others, the understanding of crucial thermohaline processes and their role in the formation of Antarctic Bottom Water, a water mass that drives the global thermohaline circulation, ventilates the abyssal ocean, and stores heat and carbon for several centuries. This multi-glider campaign, in conjunction with an increasing number of winter-time Argo floats on the continental shelf, represents a successful example of the observational capabilities of autonomous instruments in polar regions. This provides a guide for future multi-instrument surveys in such regions.

279

Machine Learning to Short-Term Near-Surface Air Temperature Forecast in Antarctic Region: Methodology and First Results

Dr.Sc. Igor Sinitsyn¹, Ph.D. Vitalii Shpyg², Dr.Sc. Anatoliy Doroshenko¹, Ph.D. Dmitry Zhora¹, Ph.D. Denys Pishniak³, M.Sc. Kateryna Huda², Ph.D. Oleksandr Shchehlov²

¹Institute of Software Systems of the National Academy of Sciences of Ukraine, Kyiv, Ukraine. ²Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and the National Academy of Science of Ukraine, Kyiv, Ukraine. ³National Antarctic Scientific Center, Kyiv, Ukraine

Abstract

Nowadays, along with numerical models of weather prediction and climate system, the machine learning is becoming widespread in the atmospheric sciences. The prediction systems with different forecast length are developed on its base: from now-casting to multi-seasonal. The hybrid modeling approaches that couple physical process models with machine learning tools to achieve the best results on post-processing stage of numerical models are investigated too. The third direction of machine learning application is connected with representation of subgrid processes.

This work is devoted to study the possibility of short-term near-surface air temperature forecast with the help of machine learning for Antarctic climate conditions. The data of T2m, which were measured on the Ukrainian Antarctic Academic Vernadsky station, with 3 hours of time resolution were used. The twelve regression algorithms were used for the machine learning. The output of these algorithms was the forecast of air temperature up to 72 hours ahead. Three metrics were used to evaluate the machine learning algorithm: R2 score, RSME and MAE.

The comparative analysis has shown that ElasticNet Regressor has the best forecasting capabilities. This method is especially good for 48-72 hour forecasting. The quite competitive methods are Support Vector Machine and K-Nearest Neighbors Regressor. The best algorithm for short-term forecasting up to 24 hours ahead is Histogram Gradient Boosting. The linear regression with classic L2 penalty demonstrates results right in the middle of the list. The ensemble methods (like Random Forest Regressor) provide slightly weaker forecast as this task does not have spatial structure and probability densities are rather smooth. As for Histogram Gradient Boosting method the MAE for 3-hour forecasting is 0.689° Celsius, for 24-hour forecasting it is 1.754°. Correspondingly, for Elastic Net Regressor the MAE for 48-hour forecasting is 2.016°, for 72-hour forecasting it is 2.155°.

281

PolarToolkit: Python Tools for Convenient, Reproducible, and Open Polar Science

Dr Matthew Tankersley

Unaffiliated, Glenwood Springs, USA

Abstract

PolarToolkit (formerly known as Antarctic-Plots) is a Python package with the goal of making polar (i.e. Antarctic, Arctic, Greenland) research more efficient, reproducible, and accessible. The software does this by providing; 1) convenient functions for downloading and pre-processing a wide range of commonly used polar datasets, 2) tools for common geospatial tasks (i.e. changing data resolution, subsetting data by geographic regions), and 3) code to easily create publication-quality maps, data profiles, and cross-sections. Additionally, PolarToolkit provides an easy means for exploring datasets with pre-defined or interactively-chosen geographic regions.

282

The use of wheeled vehicles for science support on the East Antarctica plateau

Dr. Michael Jackson¹, Dr. Weisen Shen², Sune Tamm³, Jessie Crain¹

¹National Science Foundation, Alexandria, USA. ²Stony Brook University, Stony Brook, USA. ³Arctic Trucks, Reykjavík, Iceland

Abstract

The US National Science Foundation is supporting high priority research to seismically investigate the subsurface structure and thermal properties of the underlying crust near the South Pole. As a novel support approach, the program engaged with Arctic Trucks, a company which re-engineers OEM light duty vehicles to travel in extreme snow and ice conditions safely and reliably, including those found at the South Pole. Over the past Antarctica field season (2023-2024), Arctic Trucks provided two Hilux AT44 trucks to support a USAP science team to perform 40 days of fieldwork near the South Pole station, Antarctica. The team installed nine broadband seismic stations and installed and retrieved 190 seismic nodes, covering two 350-400 km long transects and extending from the nearby South Pole subglacial basins to the plateau area towards the southern Transantarctic Mountains. The teams were able to travel at maximum speeds of ~ 60 km/h and average speeds of 35 km/h on the Plateau. The flexibility and speed of the Arctic Trucks wheeled vehicles allowed the science team to adjust the working plan as needed, while enabling high seismic data acquisition rate making this one of the first successful seismic node projects performed on the East Antarctica plateau. This project also demonstrates that using a private-public partnership model for logistics using wheeled, light duty traverse support allowed the rapid execution of science where traditional platforms (fixed wing, snowmobile, or PistenBully) were not an option.

283

Isolation and Mercury Reduction Capacity of Micrococcus sp. from Signy Island, Antarctica

Mr Jiei Kobe¹, Mr Dani Wijaya^1,2, Dr Faradina Merican Mohd Sidik Merican³, Dr Peter Convey^4,5, Dr Japareng Lalung^1,6

¹School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia. ²Center for Advanced Engineering and Innovation, Nurul Fikri Collage of Technology, South Jakarta, Indonesia. ³School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Department of Zoology, University of Johannesburg, Johannesburg, South Africa. ⁶Centre for Global Sustainability Studies, Universiti Sains Malaysia, Penang, Malaysia

Abstract

Mercury (Hg), known for its severe toxicity to both human health and the environment, is extensively utilized in various technological industries. This study assessed the potential of the bacterium Micrococcus sp., originally isolated from Signy Island in the maritime Antarctic, as a Mercury Reductase Bacteria (MRB) for bioremediation purposes. The strain's tolerance level and reduction capacity for Hg were studied using the Kirby–Bauer disk diffusion method and the broth dilution method, respectively. The strain exhibited an Hg tolerance level of 100 mg/L, with Hg reduction rates of 49.30%, 9.05%, 47.63% and 50.48% at concentrations of 100, 125, 150, and 175 mg/L after a 72 h incubation at room temperature. Regression analysis of the Hg reduction data revealed a regression slope of 0.738 (R2 = 0.825). The results obtained support the efficacy of Micrococcus sp. efficacy in mercury reduction, establishing its potential as an MRB.

Keywords: Mercury Reductase Bacteria, Micrococcus sp., Bioremediation, Mercury tolerance, Hg reduction capacity

284

Soil micromorphology in periglacial environments of Harmony Point, Nelson Island, Maritime Antarctica

Willam Fortes Rodrigues¹, Fábio Soares de Oliveira², Carlos Schaefer³

¹SEDU, Juatuba, Brazil. ²UFMG, Belo Horizonte, Brazil. ³UFV, Viçosa, Brazil

Abstract

Pedological research in ice-free areas of Maritime Antarctica has expanded significantly, yet micromorphological investigations remain limited. To address this gap, we conducted a study on seventeen soil profiles from Harmony Point, Nelson Island, representing three soil groups: permafrost-affected patterned ground soils, organic soils from flooded depressions with mosses, and ornithogenic soils. Employing trinocular optical microscopes and quantitative spot microchemical analyses (WDS) using electron microprobes, we examined microstructures and microchemical properties. Across all soil groups, microstructures were characterized by the relative distribution of the groundmass, and two main aggregation types were observed: subangular blocky and granular. Patterned ground soils exhibited structures linked to frost heave, with lithological control evident in coarse material due to primary mineral abundance. Flooded depression soils highlighted organic matter's role in granular microstructure development and biogeochemical weathering. Ornithogenic soils displayed crumbs, and basic enaulic microstructures, indicative of orbicular phosphorus-rich material formation. Microchemical analyses revealed interactions between phosphorus-rich solutions and elements like aluminum, iron, and potassium, yielding amorphous and crystalline phosphorus pedofeatures in coatings, fillings, and micromass impregnations. Our findings underscore the critical role of microscale soil morphology in understanding pedogenesis and periglacial processes in Maritime Antarctica.

286

Thermal variations of the active layer in Fildes Peninsula, Maritime Antarctica

Dr André Andrade^1,2, Dr Roberto Michel³, Dr Ulisses Bremer⁴, Dr Elias Lima Neto⁵, Dr Gonçalo Vieira⁶, Dr Carlos Schaefer⁷, Dr Jefferson Simões⁴

¹Federal University of the Jequitinhonha and Mucuri, Unaí, Brazil. ²Polar and Climate Center, Porto Alegre, Brazil. ³Universidade Estadual de Santa Cruz, Ilhéus, Brazil. ⁴Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁵Universidade de São Paulo, São Carlos, Brazil. ⁶Universidade de Lisboa, Lisboa, Portugal. ⁷Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

This work aimed to characterize the variation in the thermal regime of the active layer in a permafrost area on Fildes Peninsula, Antarctica, and relate this variability with meteorological data between 2014 and 2016. The monitoring site was installed to continuously monitor the temperature and moisture of the active layer, radiation flow on the surface, and air temperature. We used data collected to generate the indexes freezing degree-days, thawing degree-days, frost number, n-factor, apparent thermal diffusivity, and active layer thickness. The temperature of the active layer is not homogeneous, varying with depth and position in the transect, with the greatest variations in soil with better drainage and lower moisture content. Among the evaluated factors, air and soil surface temperature are the ones that most influence the thermal gradient of the active layer. We identified that near the surface there is a greater influence of albedo and cloudiness and at -35 cm depth there is a greater influence of net radiation and soil moisture. The average depth of the active layer in 2014 was -44.3 cm and in 2015 -47.7 cm and the frost number index indicates that there was a predominance of continuous permafrost in the transect during the monitoring.

288

A Seasonal Comparison of Prokaryotic Diversity in the Waters of the West Antarctic Peninsula

Wade Jeffrey¹, Hope Ebert¹, Leila Harris¹, Arianna Simmering¹, J.D. Grattepanche², Elizabeth Everett¹, Becky Gast³, Robert Sanders², Lisa Waidner¹, Jane Caffrey¹

¹University of West Florida, Pensacola, USA. ²Temple University, Philadelphia, USA. ³Woods Hole Oceanographic Institute, Woods Hole, USA

Abstract

Three transects along the West Antarctic Peninsula were sampled during three cruises; two in austral autumn and one in austral spring. Intra- and inter-seasonal comparisons in water column microbial diversity (16S rDNA gene sequencing) were made. Multiple analytical methods were used to characterize the environmental conditions and prokaryotic community structures, and further analyses were used to determine which environmental metadata might best explain the prokaryotic community compositions identified at each station within the transects. We conclude that the prokaryotic community structures from the samples collected in autumn were most influenced by latitude with three distinct clusterings in the sampling region. Dissolved nutrient concentrations was the other most influencing factor. The community structure patterns from samples collected in spring were most associated with latitude, although the clear clustering into three distinct communities was not as strong as it was in the fall. Net average primary production rates were also correlated with community structure. Comparisons between cruises indicated that season was a greater predictor of prokaryotic community composition than geographic location, coincident with findings from previous research on this region. We are in the process of completing the analyses of the third cruise (Autumn) in which full water column samples were collected. The first autumn cruise was limited to surface samples. These results should provide for a more robust comparison between the two seasons.

289

Seasons of Water and Ice: A photographic comparison in the West Antarctic Peninsula

Wade Jeffrey, Virginia Vanneman

University of West Florida, Pensacola, USA

Abstract

The Antarctic Peninsula has been highly affected by climate change and global warming, reducing ice cover and changing population dynamics of some of the Antarctic’s best-known organisms. Two oceanographic research cruises were conducted along the West Antarctic Peninsula in Autumnal fall and Spring in support of a larger project examining the dynamics of mixotrophic phytoplankton. While the majority of Southern Ocean science occurs in the autumnal spring and summer, autumnal fall is less frequently sampled and imagery more rare. The seasonal contrast required for that study provided and excellent opportunity to look for seasonal differences in colors and textures between the water, ice, cloud cover, and land masses. The autumnal cruise was marked by low light levels (approximately 6 hours of daylight) and reduced sea ice. Icebergs were noted by the diverse weathering patterns. In contrast, the spring was characterized by greater sea ice cover and almost 24 hours of daylight. Weathering was not as pronounced. The southern-most stations in Marguerite Bay were noted by brilliant red sunrises and the longer days in the spring provided dynamic colors at sunset. During both cruises we were able to take advantage of calm, protected waters which often provided mirror-like reflections of icebergs and land masses, some during bright sunny days, and some during darker more overcast days. Seasonal differences in the presence/absence of charismatic macrofauna also provided opportunities for unique images. As climate change continues, the imagery from the West Antarctic Peninsula will also change making each observation a unique experience.

291

Assessing recent Antimony Pollution: From Andean Mountains to Polar Extremes

Dr. Rafael Reis¹, Dr. Rafael Ribeiro¹, Dr. Jefferson Simões¹, Dr. Noberto Dani¹, Dr. Elena Di Stefano², Dr. Giovanni Baccolo³, Dr. Barbara Delmonte²

¹UFRGS, Porto Alegre, Brazil. ²DISAT - University Milano Bicocca, Milan, Italy. ³Paul Scherrer Institut, Villigen, Switzerland

Abstract

Antimony (Sb), widely present in the environment since ancient times, occurs naturally in the Earth's crust at concentrations below 1 mg kg^–1. It is emitted into the environment through both natural processes and modern activities such as PET (polyethylene terephthalate) manufacturing and brake lining production. Glaciers serve as important indicators of atmospheric Sb deposition, reflecting increased levels since the Industrial Period due to human activities like metal production and fossil fuel combustion. The global pollution is evident even in remote Polar Regions with significant enrichment observed in central East Antarctica. South American records show high levels that raise concerns for downstream population consumption, considering that water supplies are highly dependent on glacier meltwater during dry seasons. Here, we provide a snapshot analysis of this element in 21st-century samples from an Andean glacier record. We analyzed multi-elements using the instrument neutron activation analysis (INAA) technique a total of eighteen samples (five from dry and four from wet seasons) divided by fine and coarse size-range. Our findings reveal notably high levels of this element in Quelccaya Ice Cap (QIC, Peru), and we compare this impact proportionally considering the last 1,200 years from the same site. The enrichment factor (EF) by scandium demonstrated that fine and coarse particles were moderately enriched (EF from 10 to 100) during dry seasons, while levels above 100 were recorded in the wet seasons. In addition, our findings compares the effectiveness of policy introduction in the South America region using the Andean and polar records in the last decades demonstrating their differences. This study sheds light on the significant impact of anthropogenic activities on the QIC, highlighting the need for comprehensive environmental monitoring and proactive policy measures.

292

Heart and white muscle of the Antarctic fish marbled rockcod, Notothenia rossii, respond differently to gradual increases in temperature

Maria Rosa Dmengeon Pedreiro de Souza Maria Rosa Pedreiro de Souza¹, Tatiana Herrerias Tatiana Herrerias², Diego Mauro Carneiro Pereira Diego Pereira¹, Ananda Karla Alves Neundorf Ananda Neundorf¹, Mauricio Osvaldo Moura Mauricio Moura¹, Lucélia Donatti Lucélia Donatti¹

¹Federal University of Paraná, Curitiba, Brazil. ²Federal University of Santa Catarina, Florianópolis, Brazil

Abstract

Temperature changes observed in the Antarctic continent, mainly in the Antarctic Peninsula, have raised questions about the thermal plasticity of fish in these ecosystems. In light of this, this study aimed to understand the effects of gradual temperature increase on thermal tolerance of energetic metabolism of carbohydrates and lipids in the heart and muscle of marbled rockcod (Notothenia rossii), a notothenioid found in Antarctica. Animals underwent a gradual temperature increase of 0.5 °C/day up to 2 °C, 4 °C, 6 °C, and 8 °C. They were acclimated at each temperature stage and kept at the final temperature condition for 4 days. Both analyzed organs had different metabolic changes. No changes were observed in the markers used in the heart, was able to overcome the thermal stress caused by the evaluated gradual temperature increase. As for the muscle, we observed an increase in the activities lactate dehydrogenase, malate dehydrogenase, and hydroxyacyl-CoA dehydrogenase at 2 °C and lactate dehydrogenase at 8 °C. These results show that, at the beginning of acclimation, muscles’ energy demand increases, possibly due to a higher glucose consumption with activation of the anaerobic and gluconeogenesis metabolism, in addition to activation of the pentose phosphate pathway, due to increased activity of glucose 6-phosphate dehydrogenase. This increase in hydroxyacyl-CoA dehydrogenase indicates that fatty acids are used as energetic substrates. At 8 °C, anaerobic metabolism and glucose 6-phosphate dehydrogenase activity took place in the muscle. We conclude that both the heart and white muscle tissue are capable of withstanding a gradual increase in temperature in the short term, which is an indicator of the relative thermal plasticity of this species.

Keywords: notothenioid, acclimation, Admiralty Bay, carbohydrate metabolism, lipid metabolism, metabolic enzyme

293

Estimation of mid-Holocene East Antarctic ice history using GNSS observations and GIA modelling

Dr. Jun'ichi Okuno^1,2,3, Dr. Akihisa Hattori⁴, Dr. Koichiro Doi^1,3, Dr. Yuichi Aoyama^1,3

¹National Institute of Polar Research, Tachikawa-shi, Japan. ²Research Organization of Information and Systems, Tachikawa-shi, Japan. ³SOKENDAI, Tachikawa-shi, Japan. ⁴Geospatial Information Authority of Japan, Tsukuba-shi, Japan

Abstract

The history of ice melting and the viscoelastic response of the Earth’s mantle heavily influence Antarctic crustal deformation caused by Glacial Isostatic Adjustment (GIA). The interaction between ice history and mantle viscosity further complicates the complex Antarctic GIA. Nonetheless, geodetic observations, such as GNSS, are crucial for constraints on the GIA model parameters.

For over two decades, the Japanese Antarctic Research Expedition (JARE) has been using GNSS and absolute gravity measurements to obtain data along the coast of Lützow-Holm Bay, primarily at Syowa Station (e.g., Aoyama et al., 2016, GJI; Hattori et al., 2021, GRL). This study examines the geodetic signals associated with GIA from observations along the coastline of Lützow-Holmbukta in East Antarctica, and we also conduct GIA simulations based on the recent report of rapid ice thinning in the target region during the mid-Holocene.

Based on geomorphological surveys and surface exposure ages, Kawamata et al. (2020, QSR) showed that the region experienced rapid ice thinning of over 400 m from about 9 to 6 ka. Representative deglaciation models, such as ICE-6G (Peltier et al., 2018, JGR) do not account for this rapid thinning process. Therefore, we investigate the variability of the geodetic signals using the ice history, including this rapid thinning. Our predictions demonstrate that incorporating the modified ice history results in consistent outcomes with the observations. This finding supports the notion that rapid ice melting occurred in the Holocene and suggests geodetic observations can help constrain this region's ice sheet melting process. Additionally, we will present a possibility of the readvance following the rapid retreat based on the precise GIA modelling.

294

Perspectives on a better engagement in the ATS decision-making process

Miss Anaïs Rémont

ANCORS - University of Wollongong, Wollongong, Australia

Abstract

Since the beginning of the 21^st century, many have highlighted the “ongoing democratic deficit” in the Antarctic regime and called for more democratic governance by acting on different factors.^{^[1]}

In a paper wrote by Thomas Lord from the University of Canterbury, he explained that “scientific cooperation represents both a shared value, and a mechanism for building greater trust and interdependence between States in the Antarctic”.^{^[2]} He also highlighted the fact that peace and scientific cooperation represent the core values of the Antarctic Treaty as established by its Preamble and its Article I. Consequently, “[t]he key currency in Antarctic governance, however, remains scientific output, and thus, the ability to gather and disseminate scientific knowledges […] collected in the hands of few wealthy States.”.

Indeed, the Antarctic Treaty System (ATS) was not concluded under the auspices of the United Nations, unlike most international environmental law agreements or frameworks for Areas Beyond National Jurisdictions. By establishing specific requirements to have a voice in the decision-making process, the Antarctic Treaty remains hugely criticised as a “rich man’s club”. Therefore, many questions persist regarding the ATS’ ability to enable developing countries who are already parties to the Treaty but still do not have a word to say because of their lack in financial and scientific means.

[1] Brady, Anne-Marie, ‘Opinion: Democratising Antarctic Governance’ (2012) 2(2) Polar journal 451. See also Hemmings Alan D, “Re-justifying the Antarctic Treaty System for the 21^st century: rights, expectations and global equity” in Polar Geopolitics?: Knowledges, Resources and Legal Regimes, edited by Richard C. Powell, and Klaus Dodds, Edward Elgar Publishing Limited, (2014).

[2] Lord, Thomas, ‘The Antarctic Treaty System and the Peaceful Governance of Antarctica: The Role of the ATS in Promoting Peace at the Margins of the World’ (2020) 10(1) Polar journal 3.

298

Monitoring brown skua (Stercorarius antarcticus) foraging behaviour with tracking loggers during the breeding period at ASPA 128, King George Island

Katarzyna Fudala, Prof. Robert Bialik

Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland

Abstract

NANO solar-powered GPS–Bluetooth–ACC trackers (Druid Technology Co., Ltd., China) were installed on three pairs of brown skuas (Stercorarius antarcticus) to monitor their movements during the 2022/2023 breeding season. The birds' nests were located near a colony of approximately 2,500 Adélie penguin nests on Point Thomas in the ASPA 128 at King George Island (KGI). The trackers were installed during the incubation period (14 to 22 November 2022). Each of the six loggers reported bird positions between 24 and 144 times per day, and this number was adjusted according to the battery level of the recorder. All three pairs of birds were successful at breeding, and for two pairs, the chicks achieved flight. In comparison, for all 44 skua territories that were observed during the 22/23 season in the whole ASPA 128, only 19 pairs (including two with transmitters) had fledglings. Analysis of the results revealed two significant periods of skua behaviour related to Adélie penguins leaving their colony. First, during the penguins’ breeding period, neither males nor females left their territories. In addition, our results allow us to define the boundaries of these territories. This process continued until 28-31 January 2023, when the last young Adélie penguin left the colony. This coincided with all three male skuas starting to forage far away from their territories, reaching Livingston Island and travelling a distance of more than 80 km each day before returning to their nests. In contrast, one female from the pair that lost her brood flew away and did not return to her territory for the remainder of the season. Another, presumably following the Adélie penguins, flew to Gourdin Island on the Antarctic Peninsula, which is located more than 130 km from KGI, and spent 4 days. The third female was still guarding her chick at the end of the season. All the obtained bird positions and a few exemplary trajectories of bird movements are presented.

299

Spectral and physical insights into glacial meltwater plumes near Zalewski Glacier: Unoccupied aerial vehicles revealed heterogeneous sediment dynamics

Dr Kornelia Wójcik-Długoborska, Prof Robert Bialik

Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland

Abstract

During the austral summer of 2019, 2020, and 2021, research into the spectral properties of glacial meltwater plumes near Zalewski Glacier on King George Island in the South Shetland Archipelago was conducted. Due to the specific tectonics of the substratum and faults under the Zalewski Glacier, turbid plumes with heterogeneous sediments were observed. To measure the spectral properties of meltwater plumes, unoccupied aerial vehicles were used. A Parrot Bluegrass drone with a multispectral Sequoia+ sensor was used to register the remote sensing reflectance of turbid water. Using a DJI Inspire 2 quadrocopter with a Zenmuse X5 camera, the predominant colour and shape of the plumes were identified. In situ measurements with a CTD sonde, LISST sonde and water filtration allowed us to determine the physical properties of the sedplume. Our results showed differences in the spectral and physical properties of two distinguished plumes. Plumes with predominant red sediment were characterized by a smaller mean sediment particle size, higher turbidity and higher suspended sediment concentration than those with white suspension. However, the red sediment, despite its physical properties, reflected significantly less electromagnetic radiation than white sediment. This indicates that chemical properties (affecting colour) may have a greater impact on the spectral characteristics of the suspension than physical properties.

302

GRAVITY DATA ANALYSIS BY WAVELET TRANSFORM

Mr. SUNJAY SUNJAY

Seismic Imaging Centre , Geophysics , BHU , Varanasi , India, Varanasi, India

Abstract

Geophysical technology passive source potential method gravity ,airborne gravity, satellite gravity ,magnetic, magnetotelluric,earthquake data passive seismic imaging and active source reflection exploration seismology , electromagnetic, ground penetrating radar , etc. are employed for lithosphere subsurface imaging for extractive industries hydrocarbon mining mineral coal ,geothermal , natural geologic white hydrogen and earth crust (continental and oceanic) architecture basin analysis. Geophysical signals are multiscale and nonstationary in character.The multiscale decomposition of the geophysical data takes into account the timescale localization properties of the wavelet transform. In computation dilation property comes first then translation, this is not commutative for wavelet transform.. Spectral leakage smearing of wavelet transform is corrected by synchrosqueezed wavelet transform nonlinear nonstationary signal empirical mode decomposition. The Wavelet-based multi-scale analysis is a powerful tool for multiple decomposition of potential field data. Discrete wavelet transform generates low-order wavelet details that keep invariant scales with the total order number; while the change in the total order number can only increase wavelet details of high orders and the degree of smoothness of the final approximation. Thus, one can combine wavelet details based on regional geology to decompose gravity anomalies, producing anomalies correlated to certain geological sources. Applying the traditional frequency spectrum analysis techniques, one can estimate the everage depth of sources for every wavelet detail, and obtain the statistics correlation between the decomposed wavelet details and the source depth.Improving resolution of gravity data with wavelet analysis : Gravity data are the results of gravity force field interaction from all the underground sources. Separation of the regional gravity anomaly using wavelet multi-scale analysis and choose rational decomposition results based on the spectrum analysis and their depth estimation results. Joint inversion gravity , magnetic and seismic data is very efficient for precise subsurface imaging lithosphere.Machine learning is employed for wavelet transfor gravity data analysis.

309

Antarctic wastewater: a local source of microplastic pollution

pHD Student Nathalie Bernard^1,2, Dr Lucas Ruberto^3,1, Tec François Oberhaensli², Dr Marc Metian², Dr Cristian Vodopivez³, Dr Carlos M Alonso-Hernandez²

¹Instituto de Nanobiotecnología (FFyB UBA-Conicet), Buenos Aires, Argentina. ²Marine Environment Laboratories, Department of Nuclear Science and Application, International Atomic Energy Agency, Monaco, Monaco. ³Instituto Antártico Argentino, Buenos Aires, Argentina

Abstract

This study describes the occurrence of microplastics (25-200 μm) found in the discharge water of the wastewater treatment plant (WWTP) at Carlini Base, an Argentinian research station on King George (25 de Mayo) Island. The Samples were analyzed by micro-Raman spectroscopy and revealed an abundance of microplastics, ranging from 64 to 159 particles per liter of wastewater. This amount is comparable to that found in other WWTPs around the world. Approximately 80% of the identified particles were smaller than 40 μm. Chemical characterization identified predominant polymers including polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and polystyrene (PS), among others. By identifying WWTPs of research bases in Antarctica as sources of microplastic pollution, this study highlights the urgent need for better wastewater treatment technologies for research bases in remote areas of the planet in particular, aligning with the objectives outlined by the Secretariat of the Antarctic Treaty, and for wastewater treatment in general around the world to mitigate this environmental threat.

311

Occurrence of faecal sterols in surface sediments of Collins Bay, Antarctica, and the evaluation of their sources by diagnostic ratios

B.Sc Jamile Nasser¹, Ph.D Ana Caroline Cabral², B.Sc Gabrielle Lube¹, Ph. D Natalia Venturini³, Ph.D César Martins¹

¹University of São Paulo, São Paulo, Brazil. ²Federal University of Paraná, Pontal do Paraná, Brazil. ³University of La Republica, Montevidéu, Uruguay

Abstract

Antarctica is well known as a preserved environmental continent, but vulnerable to human influence for local and global activities. Maxwell Bay, located on King George Island, is one of the main inhabited areas that host several scientific stations, including the Uruguayan ‘General Artigas’ research station situated at Collins Bay. Wastewater disposal is considered a potential source of environmental impacts in the Antarctic marine system, requesting studies of the monitoring of quality conditions. Therefore, we analysed the occurrence and distribution of coprostanol (cop) and epicoprostanol (epi) in the sediments of Collins Bay to evaluate traces of faecal material from sewage in this sensitive area. Surface sediments from ten sites were sampled during 2019 and were analysed using gas chromatography with a flame ionization detector after Soxhlet extraction and liquid adsorption column purification. Additionally, diagnostic sterol ratios were applied to evaluate the main sterols sources in the region. 'Cop' and “Epi’ were detected in all sampled sites, ranging from 0.06 (M2 and M3) to 0.24 µg g^-1 (BC3C) and from 0.06 (BC1C) to 0.80 µg g^-1(BC3C), respectively. These ‘cop’ levels are in the same ranges that found in sites around other research stations, e.g., Brazilian research station. The cop/epi ratio was < 1.5, obtained for all sites, that suggests contributions of faecal sterols from marine mammals, indicating biogenic sources. The ratios cop/(cop+cholesterol) and %cop+epi/total sterols indicated values < 0.5 and < 50%, respectively, indicating an absence of sewage contamination. The results obtained suggest a predominance of natural sources of sedimentary organic matter and low contribution of wastewater effluents into this Antarctic site. Moreover, these markers can be useful indicators of human-derived faecal input and contributing to monitoring programs to prevent anthropogenic impacts.

312

Mass Balance estimation for a segment of the Quito Glacier period 2011-2020 and its relationship with global climate events

Msc. BOLÍVAR CÁCERES

INAMHI, QUITO, Ecuador

Abstract

During the austral summer of 2010, a network for measurements was installed for estimate the Mass Balance near a little glacier in the proximity of the Ecuadorian Station Pedro Vicente Maldonado located on Grenwich Island, consisting of plastic ablation stakes located between 15 and 95 meters above sea level over two segments of the Glacier named as Quito (Traub according to international nomenclature). Annual ablation values were obtained for a period of eight years of measurements over the network. Despite being a short statistic series of data, it is about making a first interpretation in relation to the occurrence of two global phenomena: the Southern Annular Mode (SAM) and El Niño Southern Oscillation (ENSO) with the purpose to be able to explain the evolution of the mass balance in relation to its occurrence.

314

Mineralogical constrains on the P-T evolution of granulites in the Bunger Hills, East Antarctica

Ilnur Abdrakhmanov¹, Ph.D Yuri Gulbin²

¹Institute for Geology and Mineral Resources of the World Ocean, Saint-Petersburg, Russian Federation. ²Saint-Petersburg Mining University, Saint-Petersburg, Russian Federation

Abstract

Spinel- and orthopyroxene-bearing metapelitic granulites exposed in the Bunger Hills, East Antarctica have been intensively studied in recent years because they are supposed to record evidence for UHT metamorphism. Detailed petrographic observations, whole rock and mineral chemistry, together with SIMS trace element data on quartz, garnet, and orthopyroxene, are presented for these rocks. Mineral thermobarometry including Al-in-orthopyroxene, ternary feldspar, Ti-in-quartz, and Fe-Ti oxide solvus, has been used to quantify the UHT conditions. Based on phase equilibrium modeling, tight clockwise P-T path has been deduced, which involves near isobaric heating at 6-7 kbar to ~940–1030 °C followed by near isobaric to slightly up-pressure cooling at 5-6 kbar to ~750 °C. It is concluded that the outlined metamorphic history is characteristic of an extensional crustal regime which is also evidenced by the correlation of prograde and retrograde metamorphism with extensional and compressional phases of major ductile deformations recognized in the region. In order to constrain tectonic setting of the granulites, this result is discussed in the context of current views on Mesoproterozoic evolution of the Albany–Fraser Orogen, the westernmost part of which Bunger Hills are considered to be. This metamorphic history contrasts with down-pressure P–T path reported for the Bunger Hills earlier, and is almost identical to tectono-thermal evolution in the extensional setting proposed for Stage-2 of the Mesoproterozoic Albany–Fraser Orogeny. To be more specific, the peak assemblages of the studied granulites are assumed to be associated with the main extensional phase of orogeny, whereas post-peak assemblages may be related to the late-orogenic contractional event responsible for crustal thickening.

317

Assessing the threat of non-native species transported via kelp rafts to shallow marine Antarctic ecosystems.

Miss Lydia Brackwell¹, Dr Paul Brickle², Professor Rodney Forster¹, Dr Huw Griffiths³, Dr Cath Waller¹

¹University of Hull, Hull, United Kingdom. ²South Atlantic Environment Research Institute, Stanley, Falkland Islands (Malvinas). ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Kelps are found along 25% of coastlines, representing some of the world’s most productive habitats, especially at higher latitudes. They play a key role in maintaining biodiversity, habitat provisioning and ecosystem function. During disturbance events such as storms, kelp individuals can detach from the benthos, and form kelp rafts. These rafts are known to transport a variety of fauna and flora which may not have a pelagic life history phase, beyond their biological limits, driving biogeographic patterns. There are ~ 70 million kelp rafts drifting in the Southern Ocean, some reportedly reaching Antarctic shores, which may pose a threat to shallow Antarctic marine ecosystems. The goal of this project is to assess what macrofauna are associated with kelp holdfasts in-situ around the Atlantic sub-Antarctic, and to determine which species could survive rafting and become established in Antarctica, both now and under different warming scenarios. This project will integrate a combination of in-situ surveys, physiological assessments, and novel experimental approaches on the kelp forests of the Falkland Islands and Patagonia to investigate the potential impacts of kelp raft dispersal in the Southern Ocean. The methodology will investigate spatiotemporal community variability between bull kelp, Durvillaea antarctica, and giant kelp, Macrocystis pyrifera, in the sub-Antarctic. Surveys using scuba will be supplemented with laboratory dissections of kelp and complemented with CT scans to gauge holdfast habitat heterogeneity. Additionally, in-situ experiments simulating thalli detachment will elucidate behavioural responses of species associated with kelp to detachment and rafting. Finally, physiological assessments of selected macrofauna invertebrates will develop understanding of survivorship during rafting journeys using environmental conditions organisms will experience both now and under potential warming scenarios. The findings will contribute to the understanding of the potential impact of climate-mediated range expansions on Antarctic and sub-Antarctic marine biodiversity, informing management strategies in the face of environmental change.

318

Changes in the icefield of King George Island and climatic variability between 1988 and 2020

MSc. Júlia Lopes Lorenz¹, PhD. Kátia Kellem da Rosa¹, PhD. Carina Petsch², PhD. Cleiva Perondi¹, MSc Filipe Darós Idalino¹, PhD. Jeffrey Daniel Auger¹, PhD Rosemary Vieira³, PhD. Jefferson Simões Cardia¹

¹Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Universidade Federal de Santa Maria, Santa Maria, Brazil. ³Universidade Federal Fluminense, Niterói, Brazil

Abstract

This study examines air temperature variability and glacial area changes in King George Island between 1988 and 2020/2022. To determine changes in the glacier area, the study used Sentinel-2 and Landsat satellite images mapping and normalised indices (NDSI and NDWI). Climatological data were obtained from ERA5, which is accessible through Google Earth Engine. The study analysed trends and anomalies in atmospheric temperature, U-wind, and V-wind. The glacier area for 2020 was found to be 999.95 km², and the losses over the period were 104.9 km² (error <1%) and a retreat of 3.17 km²/year. The study found that the Keller Peninsula glaciers and Bellingshausen Dome experienced the most significant losses (28% and 17%, respectively), while the Warszawa, Kraków, and Eastern icefields obtained losses of 15.6%, 13%, and 10.4%, respectively. The Kraków, Warszawa, and Bellingshausen Dome icefields showed the highest area loss in the 150 m elevation range in period. The study also observed a warming trend in autumn since 1988. Since 2010, both autumn and summer temperature have increased significantly. The estimated increase in regional surface temperature since 2010 may correspond to the end of a cooling period observed in other studies. It may explain the area loss in the recent period. The area loss values (%) increased with decreasing dimensions and lower maximum elevation of the icefields. Calving glaciers with ice flow towards deeper and steeper submarine sectors (associated with the Bransfield Strait) experienced the highest area loss. Moreover, atmospheric warming was more significant in the Bransfield Strait than the Drake Passage.

320

EXPERIENCE OF COLOMBIAN IN ANTARCTIC GLACIOLOGICAL STUDIES TO PLAN THE FIRST SCIENTIFIC CROSSING OF COLOMBIA TO THE GEOGRAPHICAL SOUTH POLE 90° SOUTHERN LATITUDE

MSc. Diego Fernando Mojica-Moncada^1,2,3,4,5, Dr. Jhon Fredy Mojica-Moncada^1,2,6,7,8, Dra. Dalia C. Barragán-Barrera^1,2,9,4, Dr. Carlos Cardenas⁵, Dr. Gino Casassa⁵

¹Asociación de Jóvenes Investigadores Polares de Colombia (APECS Colombia), Bogotá, Colombia. ²Programa Antártico Colombiano, Bogotá, Colombia. ³Subgrupo deTrabajo Regional de Ciencias del Agua de Antártica del Programa Hidrológico Intergubernamental (PHI-LAC) de la UNESCO, Montevideo, Uruguay. ⁴Fundación Malpelo y otros Ecosistemas Marinos, Bogotá, Colombia. ⁵Centro de Investigación GAIA Antártica (CIGA), Universidad de Magallanes, Punta Arenas, Chile. ⁶National Oceanic and Atmospheric Agency (NOAA), Miami, USA. ⁷Atlantic Oceanographic and Meteorological Laboratory (AOML), Miami, USA. ⁸University of Miami (UM), Rosenstiel School of Marine, Atmospheric and Earth Science (RSMAS), Miami, USA. ⁹Instituto Javeriano del Agua, Pontificia Universidad Javeriana, Bogotá, Colombia

Abstract

In 2017, Colombia began the glaciological study in Antarctica based on its capabilities and with the international cooperation of institutions from Chile, Germany, Perú and the United States (US). This synergy allowed developing an updated study of the Lange Glacier (LG), located in the Antarctic Peninsula, one of the areas with a tendency to increase temperature. The Antarctic Colombian Program, in collaboration with the Colombian National Navy and General Maritime Directorate, carried out oceanographic stations and bathymetry survey of Almirantazgo Bay on board the “ARC 20 de Julio”, with support of the “BAP Carrasco” of Perú. With human resources from Colombia and on behalf of the US, a network of stakes with temperature sensors was installed on the LG, and LG dynamics were estimated analyzing satellite images. Collaboration among German, Chilean, Peruvian and Colombian researchers a network of cameras for photogrammetry was also installed and a Digital Elevation Model was created. Additionally, Chilean and Colombian researchers studied physical and biological aspects that may influence the local marine ecosystem. This international and inter-institutional effort made it possible to determine the Calving flux in the LG. Additionally, an intrusion of warm external waters into the LG bay was detected, wich influences its retreat and loss of ice thickness. Due to the experience and skills acquired by Colombia and with the support of Chile, currently it is intended to carry out the “First Scientific Antarctic Crossing of Colombia to the Geographic South Pole 90° Southern Latitude” in the southern summer of 2024-2025, on whose route from the inner edge of the Ronne-Filchner ice shelf to the South Pole is estimated to cover 1,100 km by ski and sled (manhauling), to collect meteorological and snow cover information in the “Deep Antarctic”.

321

Importance of organic carbon in modeling soil density in Antarctica using machine learning algorithms

MSc. Cássio Marques Moquedace¹, MSc. Clara Glória Oliveira Baldi¹, Isabelle de Angeli Oliveira¹, Dr. Danilo César Mello¹, Sarah Gabriela Reis Silva¹, Dr. Rafael Gomes Siqueira¹, Dr. Marcio Rocha Francelino¹, Dr. Carlos Ernesto Gonçalves Reynaud Schaefer¹, Dr. Lucas Carvalho Gomes², Dr. Elpídio Inácio Fernandes-Filho¹

¹Laboratório de Geoprocessamento e Pedometria, Department of Soil Science, Universidade Federal de Viçosa, Viçosa, Brazil. ²Department of Agroecology, Aarhus University (AU Viborg), Viborg, Denmark

Abstract

Soil plays a fundamental role in global climate change, mainly due to its ability to store carbon. From this perspective, soil bulk density (BD) is essential for an accurate estimate of soil carbon stocks. Our objective was to employ machine learning algorithms to fit a pedotransfer function to BD in Maritime Antarctica (MA) and the North Antarctic Peninsula (AP). We used a legacy database from Terrantar project Federal University of Viçosa-Brazil, containing 2800 soil samples. We selected 127 samples with BD data to adjust the models. We tested four machine learning algorithms (cubist, k-nearest neighbors – k-knn, random forest – rf and support vector machines – svm) using the nested leave-one-out cross-validation method. We used easily measurable soil attributes related to BD (organic carbon content - OC, pH and sand, silt and clay content). The algorithm that performed best was cubist (concordance correlation coefficient - ρ_c = 0.52 and mean absolute error - MAE = 0.12 g cm^-3), while k-knn presented the worst performance (ρ_c = 0.37 and MAE = 0.14 g cm^-3). We observed similar performances between the evaluated algorithms. This similarity suggests that the generalizability of our pedotransfer function was satisfactory, as different algorithms led to similar results for BD in Antarctica. Regarding the importance of the variables, the OC stood out in the 127 executions of the algorithm, with an average relative importance of 89 ± 30%, while the other attributes reached importance of around 34 ± 16%. Although Antarctic soils are poorly developed and sandy, in regions where there is animal activity, pedogenesis is more advanced, and the deposit of guano provided by birds generally increases OC concentrations and conditions soils with lower densities. We obtained a satisfactory performance in adjusting the pedotransfer function for BD in AM and AP, with OC being the most important attribute.

322

Climate change and soil carbon stocks in Antarctica: insights from machine learning models

MSc. Cássio Marques Moquedace¹, MSc. Clara Glória Oliveira Baldi¹, Dr. Danilo César Mello¹, Dr. Rafael Gomes Siqueira¹, Dr. Marcio Rocha Francelino¹, Dr. Carlos Ernesto Gonçalves Reynaud Schaefer¹, Dr. Lucas Carvalho Gomes², Dr. Elpídio Inácio Fernandes-Filho¹

Abstract

Antarctica is a unique environment in its pedo-environmental characteristics, raising broad debate about soil organic carbon (SOC) stocks stored, and their role in the face of climate change. Our objective was to evaluate the pedo-environmental relationships of SOC stocks in Maritime Antarctica (AM) and the North Antarctic Peninsula (AP). We fit the quantile random forest (qrf) model with repeated cross-validation for the 0-30cm soil layer using a database from Brazilian project Terrantar, with 2800 soil samples. As environmental proxies we employed SCORPAN-derived data categorized into: climate; organisms (NDVI, NPP, and distance from penguin colonies); relief with the digital elevation model and derived variables; and parent material. Model performance was quantified using the concordance correlation coefficient (ρc), mean absolute error (MAE) and a null model (mean). The qrf reached ρc = 0.92 and MAE = 21.41 MgC ha^-1. Compared to the null model (MAE = 39.82 MgC ha^-1), the qrf presented a reduction of almost half the error. Climate variables were the most important for SOC stocks, followed by organisms, geology and relief. Although relief was ranked last, the variable ridge-level stood out, suggesting relationships between soil moisture and SOC stocks. Among the climatic variables, there was a predominance of those related to precipitation. This reinforces the relationships between humidity and SOC stocks. Furthermore, the qrf detected latitudinal humidity gradients, as the climate in AM is more humid and in PA the climate is drier. The relationships between climate and organisms are intricate, as climate moderates organisms and processes related to the biological influence (e.g. photosynthesis and guano accumulation) are needed to explain the carbon input in Antarctic soils. These findings shed light on future concerns for maintenance of the Antarctic SOC stocks in the face of climate change, highlighting climate and organisms as the main pedo-environmental moderators of SOC stocks.

323

Land surface cover change on Keller Peninsula, Maritime Antarctica: evidence of ice retreat and landscape greening

MSc. Clara Glória Oliveira Baldi, MSc. Cássio Marques Moquedace, Dr. Márcio Rocha Francelino, Dr. Carlos Ernesto Gonçalves Reynaud Schaefer, Dr. Elpídio Inácio Fernandes-Filho

Laboratório de Geoprocessamento e Pedometria, Department of Soil Science, Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

The surface cover is an important indicator of subpolar environmental change, therefore monitoring it is important in the context of global climate change. Our objective was to determine the land surface cover distribution of Keller Peninsula (KP), Maritime Antarctica (MA). We performed a hybrid classification on 500 ha of KP, combining information from photointerpretation and supervised machine learning classification to define four classes: vegetation, exposed soil/rock, water, and snow/ice. For photo interpretation classification, we used ortho mosaics generated from a Remotely Piloted Aircraft (RPA) flight in the summer of 2015 and Sentinel-2 images. We also used RGB band composition, NDVI, and MSAVI indices to delineate them in ArcGIS Pro. For supervised classification, we used approximately 1500 samples of the four classes from visual analysis of orthomosaics. The predictors were R, G, B, NIR, RedEdge, and thermal radiometric bands generated from RPA flights in the summer of 2023. We used random forest (rf) for modeling, dividing the data into training (80%) and testing (20%), using Kappa (κ) and accuracy as evaluation metrics and then predicting the area. Finally, we combined the supervised and photointerpretation classifications. The high average values obtained of κ = 0.975 ± 0.006 and accuracy = 0.98 ± indicated the potential of the methodology used for land surface classification in periglacial regions in the proposed classes. The four classes presented the following distributions concerning the total area of PK: vegetation 11.5%, exposed soil/rock 60.6%, water 0.2%, and snow/ice 27.8%. Data from previous years classified by photo interpretation showed how there has been ice/snow retreat and advance of colonization by vegetation (mosses and grasses), this may be a consequence of rising temperatures during Antarctic summers. The methodology used proved promising for surface classification of periglacial regions.

325

Is Antarctica breathing more? Increase in CO₂ flux in periglacial area

MSc. Clara Glória Oliveira Baldi, MSc. Cássio Marques Moquedace, Dr. Danilo César Mello, Dr. Carlos Ernesto Gonçalves Reynaud Schaefer, Dr. Elpídio Inácio Fernandes-Filho, Dr. Márcio Rocha Francelino

Laboratório de Geoprocessamento e Pedometria, Department of Soil Science, Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

Ecosystem respiration is an essential part of the carbon cycle and a determinant in the balance of atmospheric gases. We aimed to assess CO₂ fluxes (FCO₂) in a periglacial area between 2015 and 2023. FCO₂ collections took place during the summers of 2015 and 2023 in an exposed soil area near the Comandante Ferraz Antarctic Station, on the Keller Peninsula, King George Island, Maritime Antarctica. The soil in the area is Colluvic Skeletic Regosol (Skeletic), with an altitude of 13.6m, and no animal traffic was found. An infrared gas analyzer (IRGA) was used for ecosystem respiration (ER) collection. We used File Viewer software to adjust linear regression models for each point, and the slope coefficient was defined as the FCO₂ rate. Subsequently, we filtered the data (noisy and contamination signals) and evaluated them using descriptive and non-parametric statistics (p-value < 0.1) in an R environment. High determination coefficients (2015 = 0.63; 2023 = 0.74) indicated a predominantly linear behavior of ER. High coefficients of variation (2015 = 14.3%; 2023 = 8.9%) highlighted the difficulty of collecting FCO₂ data in the stony soil environments of Antarctica. FCO₂ in 2015 (0.17 ± 0.06 µmol CO₂ m^-2 s^-1) was 23% lower than that found in 2023 (0.21 ± 0.06 µmol CO₂ m^-2 s^-1), reaffirming the need for continuous monitoring of FCO₂ in periglacial environments, as they are dynamic and highly responsive to the pedoenvironment. We emphasize the adoption of protocols for long-term monitoring of FCO₂ and other RE-related variables that can explain whether the increases are consequences of changes caused by global warming (e.g., temperature, humidity and soil microbial diversity). ER in 2023 was statistically higher than in 2015 for the evaluated study area.

327

Decade-Long Monitoring of a Maritime Antarctic Glacier Front: Climate Change and Thermal Regime Insights

Doctor Roberto Michel¹, Doctor Márcio Francelino², Doctor Rafael Siqueira², Doctor Ivan Almeida³, Doctor Carlos Schaefer²

¹Unversidade Estadual de Santa Cruz, Ilhéus, Brazil. ²Universidade Federal de Viçosa, Viçosa, Brazil. ³IFNMG, Teófilo Otoni, Brazil

Abstract

International attention on permafrost degradation has heightened, as it is acknowledged as a significant response to climate change. Permafrost temperatures are marginally below 0 °C in Maritime Antarctic, this region of Antarctica is situated close to the climatic boundary of permafrost and has the highest sensitivity to climate change on the continent. A 1.1 °C increase in mean air temperature from 1956 to 2000 was identified , driven by global warming. This led to the accelerated retreat of glacier fronts, revealing new ice-free areas, which develop an active layer with an unknown thermal regime. This abstract describes the results of a ten-years (Feb 2011-Jun 2021) monitoring of the active layer thermal regime of a proglacial warm based glacier front in King George Island, located at the front of the White Eagle Glacier (100 m a.s.l), which has retreated ~500 m since 1988. The studied soil is a sandy loam texture Cambic Cryosol (Eutric, Turbic, Skeletic) (62° 09’07’’, 58° 08’ 11’’). Global average air temperature was -2.3 °C; 2016, 2018 and 2020 presented higher averages (-1.33 °C, -1.49°C, -1.79°C) for air and for the 100 cm layer (-1.03°C, -1.12°C, -1,43°C). The yearly sum of negative daily averages was -828 °C days for the 5 cm layer and -488°C days at the 100 cm layer, which showed only 0.64°C days yearly sum of positive daily averages 2014, 2015 and 2016 did not present any positive values; the 5 cm layer summed 490°C days. Active layer thickness varied from 99 cm in 2014 to 106 cm in 2015; average for the studied period was 102 cm. The temperature profile during the studied period indicates that the active layer thickness reached a maximum of 106 cm on March 24th, 2015, responding to variations in air temperature.

328

Impacts of Cyclonic Systems on Meteorology and Glaciology of the South Shetland Islands’ Glaciers in the Northern Antarctic Peninsula

MSc Christian Torres¹, Dr Deniz Bozkurt², MSc Michael Matějka³, Dr Kamil Láska³, Dr Ricardo Jaña⁴, Dr Jorge Arigony-Neto¹

¹Institute of Oceanography, Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Department of Meteorology, University of Valparaíso, Valparaíso, Chile. ³Department of Geography, Faculty of Science, Masaryk University, Brno, Czech Republic. ⁴Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

The Antarctic Peninsula (AP) is highly influenced by deep cyclonic systems originating from the Bellingshausen Sea and traversing the Drake Passage. These systems drive severe weather events, including strong winds and blizzards, which frequently impact the region. However, few studies have examined the effects of these low-pressure systems on the environmental conditions across the South Shetland Islands (SSI) glaciers, situated in the northern AP. This study investigates their effects on local meteorology and glaciology using a combination of in-situ observations, the Polar Weather Research and Forecasting (PWRF) atmospheric model, the COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY) glaciological model, and ERA5 reanalysis. PWRF was used to generate high-resolution meteorological fields (1 km horizontal resolution) and COSIPY was employed to estimate energy and mass balance fluxes of glaciers for January and July 2013. The PWRF evaluation results revealed better accuracy and reduced bias in air-temperature, surface pressure, wind speed, solar radiation, and exhibited improved representation of orographic precipitation compared to ERA5. Additionally, we selected two case studies featuring the direct influence of low-pressure systems on the SSI: one event on 7 January and the other on 16 July 2013. These low-pressure systems affected the meteorological conditions of the SSI, leading to decreased air temperature, intense precipitation, and strong winds. These conditions favoured strong positive daily mass balances of the glaciers, with values of up to 75 mm w.e. d-1 on 7 January and 38 mm w.e. d-1 on 16 July. The temperature decrease was attributed to the advection of cold air masses from Weddell Sea by these low-pressure systems when positioned east of the SSI. Meanwhile, the increase in precipitation and wind speed resulted from the combined effect of these synoptic-scale low-pressure systems with the local topography of the SSI and a small part of northern AP.

334

South Africa’s Antarctic Gateway

Mr Ephaphrus Mamabolo

Department of Forestry, Fisheries and the Environment, Cape Town, South Africa

Abstract

Celebrations commemorating the start of the Antarctic season are a way for the nations that serve as gateways to Antarctica to raise awareness of the continent. Only a few initiatives have been initiated by the high commissioners of the Antarctic gateway countries: Argentina, Australia, Chile, New Zealand, and South Africa. Since 2016, the Ministry of Forestry, Fisheries and Environment in South Africa has been conducting bilateral and multilateral seminars to kick off the Antarctic season with some of the nation’s heading to Antarctica from Cape Town. Key stakeholders in Antarctica, including researchers, businesses, and government organisations, will be able to discuss the prospects of being an Antarctic Gateway country thanks to the establishment of collaborative initiatives by the High Commissioners of the Antarctic Gateway Nations. This is achieved by taking advantage of every opportunity where five gateway countries are represented to hold specially designed sessions at key events such as the Antarctic Treaty Consultative, Consultative Meetings (ATCM), the Convention for the Conservation of Antarctic Marine Living Resources (CCMLAR) and the Council of Managers of National Antarctic Programs (COMNAP). South Africa serves as a case study here.

335

Status and prospect of Direct Current Power Supply and Distribution Systems for Antarctic Research Stations

Lei Wang

Beijing, Beijing, China

Abstract

Diesel generators and alternating current (AC) were once common ways of generating and distributing energy at Antarctic research stations. With the rapid development of photovoltaic energy, wind power, biofuels, hydrogen power and other forms of renewable energy, consider the reasons for energy savings and emissions reduction, renewable energy had became more and more crucial for supplying power to stations.

As the effective format of the output of these renewable energy sources was direct current (DC) electricity, in order to utilize the energy efficiently, analysis was performed to assess the feasibility of achieving a DC power supply and distribution at Antarctic research stations by comparing the characteristics of DC and AC electricity in this article.

The results indicated that the use of DC power supplies in Antarctic research stations was theoretically feasible in terms of technology, safety, economical and maintenance. DC power supplies could easily connect to grids and were convenient for consuming and receiving renewable energy which were the main reasons for DC to be applied to Antarctic research stations. Based on the research of the status quo and future trends in DC power supply and distribution systems in Antarctica research stations in combination with case studies, some key technologies related to DC power supply and distribution, such as microgrid, converter and biofuels, were described in this paper, which provides a reference for plan, design, operation and maintenance of future green and net zero Antarctic research stations.

337

A decade (2013-2022) of permafrost and active layer thickness monitoring in Antarctic Peninsula Area

Francesco Grifoni¹, Mauro Guglielmin¹, Nicoletta Cannone¹, Peter Convey²

¹Insubria University, Varese, Italy. ²British Antarctic Survey, Cambridge, United Kingdom

Abstract

Since 2013 the thermal profile of two intermediate deep boreholes (≥ 30 m) located approximately at the same elevation (ca. 30 m a.s.l.) and same distance from the coast respectively at Signy Island (60°43’S) and Rothera (67°57’S) were monitored continuously. Here we will present the main results of the trend of the ground surface temperature, the permafrost temperature at the zero annual amplitude (ZAA) depth and active layer thickness (ALT). Moreover, we analysed their relationships with the main climatic factors (air temperature, snow thickness) and finally with the latitude. The two sites both located in continuous permafrost areas showed different trends for the ALT with a substantial stability (β = 0.07; R² = 0.4) and a good correlation with summer air temperature (DJF) at Signy Island while a not statistically significant trend (β = 3.7; R² = 0.1) was recorded at Rothera. At the southern site ALT was very variable ranging between only 10 cm up to more than 130 cm while at the northern one between 270 cm and 360 cm. The temperature at ZAA at Rothera and Signy was substantially stable around the values of -3°C and -1.3°C respectively. The ALT variations were statistically correlated with the summer mean air temperature (R² = 0.7) at Signy Island and at Rothera where, in addition, a good regression has been found with thawing degree days index (R² > 0.5). The quite strong increase of the snow thickness (ca. 3 cm per year) at Rothera seems to not significantly affect the ALT. The significant stability of the two essential climate variables (ECV): ALT and temperature at ZAA in both sites may be related to the climate considered period, which includes both part of the cooling phase (1999-2016) and a portion of the following strong air warming.

339

Dissolved nutrients in different ice melting periods in austral summer at Admiralty Bay, Antarctic Peninsula

Graduation student Luisa Lucarelli, Master student Antonio Almeida, Dr Vitor Chiozzini, Dr César Martins, Dr Elisabete Braga

University of São Paulo, São Paulo, Brazil

Abstract

Understanding polar marine biogeochemical processes involving the distribution and composition of dissolved inorganic and organic compounds over different time scales (weeks, months and years) contributing to identifying local environmental changes resulting from the climate changes, highlighting possible anthropogenic interference in ice melting. This study was performed in surface waters from Admiralty Bay, King George Island (Project CARBMET-CNPq), along 16 stations, where five sampling were executed aiming to evaluate inorganic and organic nutrients forms present in the start and the high of ice melting periods in austral summer (2022-2023). During start of the ice melting, the results for phosphate, total dissolved phosphorus, dissolved organic phosphorus, silicate, ammonium, nitrite, nitrate, total dissolved nitrogen, and dissolved organic nitrogen ranged as following: 1.83 – 2.11 µmol L^-1, 2.01 – 2.11 µmol L^-1, 0.03 – 0.20 µmol L^-1, 66.44 – 71.90 µmol L^-1, 0.15 – 0.51 µmol L^-1, 0.01 – 0.08 µmol L^-1, 29.76 – 32.61 µmol L^-1, 41.81 – 46.37 µmol L^-1, 9.83 – 15.40 µmol L^-1, respectively, and during high summer (maximum melting) the values ranged as following: 0.95 – 1.72 µmol L^-1, 1.32 – 1.91 µmol L^-1, 0.05 – 0.37 µmol L^-1, 34.75 – 75.23 µmol L^-1, 0.15 – 1.40 µmol L^-1, 0.02 – 0.06 µmol L^-1, 23.00 – 35.60 µmol L^-1, 43.52 – 45.80 µmol L^-1, 7.29 – 21.27 µmol L^-1. The observed decline in the dissolved inorganic nutrients concentration corresponded to an increase in its dissolved organic forms surely influenced by the significant increase in photoperiod, from the begning to the end of austral summer and the increase of biological activities showing a peculiar metabolism of high latitude regions. The photoperiod is one of responsible for favoring photosynthesis processes in the region, which, in turn, removes inorganic nutrients from the water column contributing to understand the continuity of high nutrients and low chlorophyll (HNLC) in this region despite of assimilation process.

340

Beyond the Ice: Exploring Antarctic soil and permafrost research through spatial and scientometric analysis

Msc Ícaro Vieira¹, Dr Fábio Oliveira¹, Dr Roberto Michel²

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²Estate University of Santa Cruz, Ilhéus, Brazil

Abstract

This spatial-scientific study critically examines Antarctic soil research in the period from 1958 to 2021. In doing so, 553 publications from the Web of Science and Scopus databases are carefully analyzed. The main objective of this study is to analyze the geographical distribution, productivity, co-authorship and research topics related to Antarctic soils. The results underline the high productivity and the extensive global collaboration between researchers and institutions. The research topics are diverse and focus on microbiology, pollution, bioremediation, biogeochemistry, and heat and water monitoring of soil and permafrost. The study shows a solid network of cooperation, which is a sign of the progress of science. The diversity of research topics reflects the complexity and interdisciplinary nature of Antarctic soil research, ranging from microbiology to biogeochemistry. In summary, this study provides valuable insights into the importance of polar soils as global environmental indicators. It underlines the essential contribution of Antarctic soil research to our understanding of the Earth system. The scientometric and spatial approach adopted in this study helps to understand the social and conceptual structure as well as the temporal and spatial evolution of the subject. This research underlines the importance of further studies in this area given the crucial role of polar soils in our global ecosystem.

342

Widespread near-coastal bedrock erosion surfaces in East Antarctica and their implications for long-term ice-sheet behaviour

Guy Paxman¹, Stewart Jamieson¹, Neil Ross², Mike Bentley¹, Charlotte Carter³, Tom Jordan⁴, Xiangbin Cui⁵, Shinan Lang⁶, David Sugden⁷, Martin Siegert⁸

¹Durham University, Durham, United Kingdom. ²Newcastle University, Newcastle Upon Tyne, United Kingdom. ³Alfred Wegener Institute, Bremerhaven, Germany. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Polar Research Institute of China, Shanghai, China. ⁶Beijing University of Technology, Beijing, China. ⁷University of Edinburgh, Edinburgh, United Kingdom. ⁸University of Exeter, Penryn, United Kingdom

Abstract

The sub-ice topography of Antarctica provides a crucial record of the long-term geological, geomorphological, and glaciological evolution of the continent. Analysis of the Antarctic Ice Sheet bed can help improve our understanding of the response of the ice sheet to episodes of warming in the geological past that serve as analogues for projected future climate change.

Here, we conduct a systematic search of Antarctic airborne ice-penetrating radar data to map the distribution of low-relief, low-angle, subglacial bed surfaces (‘flat surfaces’) close to the East Antarctic ice margin between Princess Elizabeth Land and George V Land (70°E to 160°E). Individual surfaces are characterised by consistent elevations over distances of 10s to 100s of kilometres, gentle slopes, and low internal relief. We map 31 separate flat surfaces, which range from 500 to 50,000 km² in area and comprise ~40% of the perimeter of this sector of the East Antarctic margin. The flat surfaces are typically overlain by slow-moving ice and bounded by deep subglacial troughs that host fast-flowing outlet glaciers.

Underneath the modern-day East Antarctic Ice Sheet, these flat surfaces are situated at a broad range of elevations. However, when the elevations are isostatically adjusted for ice unloading, the distribution narrows substantially and, alongside cluster analysis of surface morphology, indicates that they constitute a single, statistically consistent population around the entirety of this sector of the East Antarctic margin. Under ice-free conditions, the surfaces would be situated above sea level and gently dipping in a seaward direction, and we suggest that they are remnants of a widespread fluvial planation surface formed following Gondwana break-up and preserved with only minor geomorphological modification since ice-sheet inception. The presence of these ancient surfaces has important implications for the past, present, and future behaviour of the East Antarctic Ice Sheet.

343

Potter Cove’s Heavyweights: Estimation of species’ interaction strength of an Antarctic food web

Iara Diamela Rodriguez¹, Dr. Tomás I. Marina², Dr. Leonardo A. Saravia²

¹Universidad Nacional de General Sarmiento (UNGS), Buenos Aires, Argentina. ²Centro Austral de Investigaciones Científicas (CADIC), Ushuaia, Argentina

Abstract

Understanding the complex interplay between structure and stability of marine food webs is crucial for assessing ecosystem resilience, particularly in the context of ongoing environmental changes. In the West Antarctic Peninsula, global warming has led to severe alterations in community composition, species distribution, and abundance over the last decades. In this study, we estimate the interaction strength within the Potter Cove (South Shetland Islands, Antarctica) food web to elucidate the roles of species in its structure and functioning. We use these estimates to calculate food web stability in response to perturbations, conducting sequential extinctions to quantify the importance of individual species based on changes in stability and food web fragmentation. We explore connections between interaction strength and key topological properties of the food web. Our findings reveal an asymmetric distribution of interaction strengths, with a prevalence of weak interactions and a few strong ones. Species exerting greater influence within the food web displayed higher degree and trophic similarity but occupied lower trophic levels and displayed lower omnivory levels (e.g., macroalgae and detritus). Extinction simulations revealed the key role of certain species, particularly amphipods and the black rockcod Notothenia coriiceps, as their removal led to significant changes in food web stability and network fragmentation. This study highlights the importance of considering species interaction strengths in assessing the stability of polar marine ecosystems. These insights have crucial implications for guiding monitoring and conservation strategies aimed at preserving the integrity of Antarctic marine ecosystems.

344

Life History of Antarctic Toothfish in the Bellingshausen & Amundsen Seas

Ivory Carpenter¹, Dr. Cassandra Brooks¹, Rose Leeger¹, Hayley Kwasniewski¹, Illia Slipko²

¹University of Colorado Boulder, Boulder, USA. ²Division of Antarctic Marine Living Resources, Institute of Fisheries and Marine Ecology (IFME) of The State Agency of Melioration and Fisheries of Ukraine, Kyiv, Ukraine

Abstract

Antarctic Toothfish (Dissostichus mawsoni), the top fish predator in the Southern Ocean, are found throughout the waters around Antarctica. Their populations and the marine ecosystems in which they live face threats from both climate change and potential fisheries overexploitation. Research on Antarctic Toothfish has mostly been conducted in the Ross Sea, where the main commercial fisheries are located. However, fisheries are expanding, including into the Amundsen and Bellingshausen Seas. In the midst of this expansion, little is known about the toothfish populations in the Amundsen and Bellingshausen Seas. Toothfish fisheries are currently managed by the multi-national Commission for the Conservation of Antarctic Marine Living Resources. Management of toothfish depends on accurate life history information, including age and growth parameters. Like reading growth rings of a tree, fish ear bones, called otoliths, lay down layers of calcium carbonate every year and can be used to age fish. Here we use established protocols to section and age Antarctic toothfish. To develop age and growth parameters for Antarctic toothfish, we use established protocols for sectioning and then aging toothfish. We then calculated age and growth parameters, including growth rates and longevity, using a von Bertalanffy Growth Function. Age and growth parameters for fish from the Bellingshausen and Amundsen Sea were then compared to parameters for toothfish from other regions of the Southern Ocean. This work will provide accurate age and growth information for this understudied population of toothfish, informing marine conservation of this important top fish predator.

345

The June 2022 extreme warm event in Central Western Antarctica recorded by Criosfera1

Heitor Evangelista¹, Luciana Prado¹, Irina Gorodetskaya², Heber Passos³, Franco Villela⁴, Marcelo Sampaio³, Elaine Santos¹, Carla Brito¹

¹Rio de Janeiro State University, Rio de Janeiro, Brazil. ²CIIMAR, Matosinhos, Portugal. ³National Institute for Space Research (INPE), Sao Jose dos Campos, Brazil. ⁴INMET, Sao Paulo, Brazil

Abstract

The Antarctic region has the great ice sheets on Earth, where the West Antarctic Ice Sheet (WAIS) is very sensitive to warmer periods. Modern atmospheric measurements evidenced a warming trend at WAIS since the mid-20^th century resulting in glacier retreats, increased ice flows and heatwaves, all associated with an accelerated ocean evaporation and higher atmospheric water vapor transport. These conditions fuel atmospheric rivers that act at polar areas. Here we report an important atmospheric river event that incited a rapid increase of air temperature at WAIS during winter (on June 10^th 2022) recorded by the remote automatic measurement platform Criosfera 1 (84°00’00’’ S; 79°29’39’’ W, elevation 1200 m). This anomalous warm period lasted from June 10^th to early June 13^th and was associated with continuous moisture and heat transport towards the Antarctic Peninsula. The June 10^th event was the warmest in 10 years and drove air temperature elevation of 23°C in few days. We used air temperature observed data from Criosfera 1, and from reanalysis data to describe the origin, duration, and characteristics of this warm event. The related AR event originated in the Southern Pacific subtropical region and evolved towards the Southern Ocean, crossing the Northern Antarctic Peninsula and reaching 84°S, different from other typical ARs mostly restricted to the continental border. As the frequency of warm events in Antarctica has increased in the last years, this study highlights the importance of continental monitoring strategies as Criosfera1.

347

INTERANNUAL VARIATION IN BIOCHEMICAL COMPOSITION OF SUSPENDED PARTICULATE ORGANIC MATTER IN SURFACE COASTAL WATERS OF AN ANTARTIC FJORD

Msc. Maria Eugenia Pedelacq¹, Bach. Claudia Parodi¹, PhD. Luis Cerpa², PhD. Pablo Muniz¹, PhD. Natalia Venturini¹

¹Oceanografía y Ecología Marina (OEM), Instituto de Ecología y Ciencias Ambientales (IECA), Facultad de Ciencias, Universidad de la República, Iguá 4225, 11200, Montevideo, Uruguay. ²Instituto Geológico, Minero y Metalúrgico (INGEMMET), Av. Canadá 1470, San Borja, 15034, Lima, Peru

Abstract

The West Antarctic Peninsula (WAP) is considered a hotspot of climate-driven environmental change. Glacier calving and retreat has been registered, increasing freshwater inputs and contributions of terrigenous material to marine ecosystems. Changes in biopolymeric contributions of suspended Particulate Organic Matter (POM) may affect the nutritional quality of food resource, the productivity of ecosystems and ultimately the capacity of WAP fjords to act as carbon sinks and climate regulators. The aim of this work was to evaluate the interannual variation of biopolymeric composition of POM in surface marine coastal waters of Collins Bay, under the Collins Glacier influence, which is undergoing a relatively slow retreatment. Collins Bay is located to the north of Maxwell Bay, near the Uruguayan Research Station, Artigas Base, in King George Island. Water samples were taken in three austral summer seasons (2018, 2019 and 2023). Total proteins (PRT), carbohydrates (CHO) and lipids (LIP) were analyzed spectrophotometrically. PRT, CHO and LIP concentrations were converted to carbon equivalents and their sum was reported as the biopolymeric carbon (BPC) to estimate the labile fraction of POM that is easily assimilated by marine heterotrophic organisms. PRT/CHO and CHO/LIP ratios were calculated to evaluate the degradation status of organic matter and its energetic value, respectively. Predominance of PRT in 2023 indicated labile and fresh suspended POM and high nutritional quality of food available for higher trophic consumers in Collins Bay, linked with phytoplankton blooms during this austral summer. Conversely, higher contributions of LIP observed in 2019 than in 2018 and 2023 suggests high energetic value of suspended POM and more intense zooplankton grazing. Changes in BPC and biopolymeric composition suggested variations on POM quality and availability for heterotrophic marine organisms. This work provides baseline information that would be used to identify potential losses of ecosystem services induced by climate change.

349

INTEGRATED GEOMORPHOLOGICAL MAPPING AND PALEOGLACIAL RECONSTRUCTION IN ADMIRALTY BAY, KING GEORGE ISLAND, MARITIME ANTARCTIC

PhD Cleiva Perondi¹, PhD Kátia Kellem da Rosa¹, PhD Rosemary Vieira², PhD Arthur Ayres-Neto², PhD Fábio José Guedes Magrani³, PhD Jefferson Cardia Simões^4,5

¹Centro Polar e Climático, UFRGS, Porto Alegre - RS, Brazil. ²Universidade Federal Fluminense, Niterói-RJ, Brazil. ³Universität Bern. Oeschger Centre for Climate Change Research & Institut für Geologie., Bern, Switzerland. ⁴Centro Polar e Climático, Porto Alegre - RS, Brazil. ⁵Climate Change Institute, University of Maine, Orono - ME, USA

Abstract

Submarine landforms in polar fjords provides insights into the response of glaciers to climate change. The submarine landforms and processes in the Admiralty Bay (King George Island) using a multi resolution topobathymetric data based on seismic, multibeam surveys. A prominent morainal bank in the transition between the inner and middle parts marks the limit of a past stationary stage of the Dobrowolski-Goetel ice margin. Streamlined glacial lineations demonstrate an NE-SW ice flow direction and a wet-based thermal regime in the past. The evolution of the fjord in Holocene and recent decades was reconstructed. The marine glacier retreated its groundline position at the end of Admiralty Bay to the medial sector of the fjord between 9000 years BP and 7000 years BP. The ice margin stabilization between 8000 and 7000 years BP is recorded by a morainic bank. The retreat processes and a new ice margin stabilization were evidenced after this stage. The paleo-glacial flow retreated from 3500 to 2600 years BP, and a morainic bank records a glacier advance or stabilization in end of this stage. The groundline positions shift to the fjord head between 1200 years BP and the LIA. The marine glacier retreat has been faster in the last six decades than the LIA until the mid-twentieth century period. The glacier fluctuations responded to ocean and climatic input, the bedrock pinning point, and the fjord topography.

Keywords: Pinning points, morainic bank, fjord, geomorphological mapping, glacial lineations, glacier surface variation, Holocene.

351

An Evaluation ERA5 Reanalysis Near-Surface Temperature for the Argentine Islands Region

Ph.D. Vitalii Shpyg¹, Ph.D. Denys Pishniak², Dr.Sc. Liudmyla Gorbachova¹, Ph.D. Borys Khrystiuk¹, Ph.D. Oleksandr Shchehlov¹, M.Sc. Kateryna Huda¹, M.Sc. Anna Tsila¹

¹Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and the National Academy of Science of Ukraine, Kyiv, Ukraine. ²State Institution National Antarctic Scientific Center of the Ministry of Education and Science of Ukraine, Kyiv, Ukraine

Abstract

Reanalysis data is one of the most reliable sources spatio-temporal distribution of meteorological characteristics, which are measured on the existing global observing network, as well as various calculated parameters. At recent time the most widely used gridded database is the fifth generation of ECMWF atmospheric reanalysis (ERA5).

This research is devoted to the estimation of the accuracy of air temperature at 2m recovered by ERA5 in the Argentine Islands Region. For this purpose on-site meteorological observations were used. The data time resolution is 3 hours which corresponds to the standard observation times specified by the World Meteorological Organization. Both data series cover the period from 1981 to 2020 and were obtained at the Ukrainian Antarctic Akademik Vernadsky Station.

The Akademik Vernadsky Station is situated in a unique location on Galindez Island, which belongs to a group of the Argentine Islands, 8-10 kilometers away from the west coast of the Antarctic Peninsula. Automated Weather Station (AWS) has following geographical coordinates: 65.245°S and 64.256°W. The nearest grid point of ERA5 has coordinates 65.25°S and 64.25°W. Close position of the model grid point and AWS location do not require subgrid interpolation, which may be an additional source of uncertainty and deviations. Both points are actually located over the land surface of the island.

The conducted analysis showed that the values of different skill scores (ME, MAE, and RMSE) are not constant during a year and change from month to month; ERA5 reanalysis has tendency to increase accuracy over the examined time, therefore recent years reveal better correspondence with temperature observations.

352

New trends in the analysis of scientific research on Antarctica.

MSc Felipe Ríos-Silva¹, PhD Javier Benayas¹, PhD Daniela De Filippo²

¹Autonomous University of Madrid, Madrid, Spain. ²Center for Human and Social Sciences, Madrid, Spain

Abstract

Antarctica is a continent dedicated to peace and scientific research. Its status as a natural laboratory facilitates the study and monitoring of global change processes that allow decisions to be taken within the framework of the Antarctic Treaty. For this reason, it is of great interest to carry out a detailed analysis of the scientific production related to this continent worldwide.

In order to develop better Antarctic bibliometric searches at the global level, an analysis of Spanish scientific productivity on this continent was carried out. This review has identified the need to incorporate terms such as Southern Ocean in future Antarctic bibliometric studies, as well as to add new filters to refine article searches. The methodology implemented has reduced the bias caused by the appearance of articles that do not belong to Antarctic research, being an improvement to previously developed bibliometrics.

In terms of results, the trends in the scientific production of the different countries over the years have been analysed. These have increased progressively since 1900, currently reporting more than 70,000 articles. Globally, the United States, England, Australia and Germany are among the countries with the highest productivity in Antarctic science. Also, countries such as China, Chile and Brazil stand out, which have considerably increased their productivity in the last decades. The main areas of study are related to multidisciplinary geosciences, oceanography, atmospheric sciences and ecology.

This work reflects on the importance of having strategic research plans for the Antarctic continent, promoting collaboration between countries and institutions and favouring an interdisciplinary approach to current and future problems.

353

Glacial lake ice coverage variability in Fildes, Keller and Byers Peninsulas (South Shetlands) based on Sentinel-1 data

Ph.D Kátia Kellem da Rosa¹, graduate student Jorge Antônio Viel², Ph.D Carina Petsch³, Ph.D Luiz Felipe Velho⁴, Ph.D Rosemary Vieira⁵, graduate student Danielle Dall Amaria Soffiatti¹, Ph.D Jefferson Cardia Simões¹

¹Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²IFRS, Bento Gonçalves, Brazil. ³Universidade Federal de Santa Maria, Santa Maria, Brazil. ⁴IFRS campus Porto Alegre, Porto Alegre, Brazil. ⁵UFF, Niteroi, Brazil

Abstract

Glaciers are being replaced by recent ice-free areas, and a rapid global increase in lake areas is observed as an impact of recent climate changes. Glacial lakes and their components are recognized for their importance as indicators of cryosphere behaviour. Efforts have been made to evaluate the temporal variability of the ice coverage in lakes using SAR data. The study's goal is to investigate the variation in backscatter in Sentinel-1 data for interpreting freezing and melting phases of lakes in ice-free areas in Fildes, Keller and Byers Peninsulas (South Shetlands). The Sentinel -1 data were acquired in the Extra Wide (EW) swath and IW mode and either HH + HV and HH polarization with a pixel spacing of 40 e 20 m. The TSX de 2015 is StripMap (a pixel spacing at 3 m). The field campaigns at some lakes were carried out during the summer seasons of 2015–2016 and 2022–2023. S1 processing and analysis were applied in 26 lakes. Air temperature, wind speed, wind direction and total precipitation data were analyzed. The results showed seasonal (from late spring to early fall) and annual variability in the ice cover of lakes in this polar region. A backscatter threshold for ice-free water and water covered with snow and ice was obtained in both TDX image and Sentinel-1. However, the backscatter thresholds for the first class decrease between early spring and late summer. One of the lakes experienced total surface freezing only in April 2023. The temporal analysis of the meteorological parameters showed that the lakes are directly related to the ice evolution and ablation processes at the snow and ice surface.

354

Adapting to Extraterrestrial Environments: Exploring the Viability of Antarctic Nematodes in Mars and Lunar Soil Simulations

Rodrigo Goldenberg-Barbosa¹, Dafne Anjos¹, Anna Donato¹, Maithê Magalhães², Antonio Carlos Freitas¹, Fabio Bones³, Lucas Moreira², Cesar Amaral¹

¹Rio de Janeiro State University, Rio de Janeiro, Brazil. ²Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. ³Santa Catarina Federal University, Santa Catarina, Brazil

Abstract

The exploration of extraterrestrial environments has become a focal point of scientific inquiry, driven by advancements in technology and a growing interest in the potential for life beyond Earth. Analysis with sensors and analytical instruments has allowed us to understand soil compositions on celestial bodies such as the Moon and Mars. While extremophile plants have been extensively studied for potential growth on these extraterrestrial surfaces, the survival capabilities of invertebrates, particularly nematodes, remain unexplored. This study investigates the adaptability of Antarctic nematodes, known for thriving in extreme cold and isolation, to simulated Martian (MGS-1) and Lunar (LMS-1) soils. The experiment revealed differential responses in nematode survivability to the two simulants, with Lunar soil demonstrating better adaptability compared to Martian soil. The study sheds light on the intricate interactions between nematodes and simulated extraterrestrial soils, providing valuable insights for broader astrobiological considerations. Understanding the limits of life's adaptability is imperative as planetary exploration gains momentum, and this research contributes to the ongoing dialogue on the potential habitability of extraterrestrial environments.

355

Assessment of helminth biodiversity in four species of petrels and two species of skuas in Antarctica.

PhD Student Bruno Fusaro¹, Dra. Sofia Capasso^2,3, Dra. Eliana Lorenti⁴, Dr. Guillermo Panisse⁴, Student Valentina Fornillo⁴, PhD Student Lautaro Fuentes⁴, Dra. Marcela Libertelli¹, Dr. Martín Ansaldo¹, Dra. Julia Ines Diaz⁴

¹Instituto Antártico Argentino, Buenos Aires, Argentina. ²Universidad de Extremadura, Badajoz, Spain. ³3- Centro de Estudios Parasitológicos y de Vectores, CONICET-UNLP, Buenos Aires, Argentina. ⁴Centro de estudios parasitologicos y vectores, Buenos Aires, Argentina

Abstract

Almost all animals are affected by parasites at some point in their lives, making them a hidden component of biodiversity in ecosystems. A high parasite load in a host can cause physiological damage that affects nutrition, behavior and reproduction, being an important population modulator. Also, in marine environments, the parasite diversity in a host indicates the presence of other organisms (intermediate hosts) involved in their life cycle through trophic interactions. It is known that temperature increase favors the migration of parasites towards the Polar regions and towards new hosts. This highlights the role of parasites as natural markers of changes in biodiversity. Despite this, knowledge on parasites of Antarctic flying birds is limited. In this work we present the helminth diversity of four Procellariformes and two Charadriformes species collected on Antarctic Peninsula and neighbouring islands: five South Giant Petrels (Macronectes giganteus), six Snow Petrels (Padogroma nivea), eighteen Wilson’s Storm Petrels (Oceanites oceanicus), two Black-bellied Storm Petrels (Fregetta tropica), five South Polar Skuas (Stercorarius maccormicki), and twelve Brown Skuas (Stercorarius antarcticus lonnbergi). Four Cestoda (Parorchites zederi, Tetrabothrius heteroclitus, Tetrabothrius sp. and Diphyllobothrium sp.), seven Nematoda (Stegophorus macronectes, Stegophorus diomedeae, Cosmocephalus obvelatus, Seuratia shipleyi, Seuratia sp., Contracaecum sp. and Tetrameres sp.), one Acanthocephalan (Corynosoma shackletoni), and two Digenea (Renicola sp., and Gymnophallidae indet.) were found. Monitoring Antarctic parasites is key to understanding both trophic ecology and the epidemiology of infectious diseases, especially in birds with extensive migratory routes that can act as reservoirs and vectors of disease.

356

First Carbon Neutral Antarctic Expedition

Doctor Eduardo Sodré, Doctor Heitor Evangelista

Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Evidence is growing that research and tourism activities in Antarctica play an important role in the environmental impact of this region. Evidence occurs mainly associated with black carbon aerosol and its surface deposition on glacier ice and sea ice, which increases the rate of melting in areas with greater human occupation. With the aim of contributing to the sustainable development of scientific missions on the Antarctic Continent and inspired by SDG 13 “Action against Global Climate Change” of the UNITED NATIONS, the Brazilian Antarctic Program – PROANTAR, in collaboration with the Radioecology and Global Changes Laboratory (LARAMG) from the State University of Rio de Janeiro (UERJ), is implementing a proposal to inventory and neutralize greenhouse gas emissions from its mission “Cryosphere 1 2024-2025” to the Center of Antarctica, latitude 84S. Through this initiative, emission inventory estimates were made and recorded in the “GHG Protocol tool version 2023.0.3” spreadsheet, for public use. Logistics operations in central Antarctica use large and small commercial aircraft as support, cargo planes such as the Ilyushin IL-26, a polar ship, a snow tractor in addition to sources of emissions resulting from stays throughout the mission. Our estimate for the Criosfera 1 2024-2025 mission estimated, considering travel, energy consumption, fuel, transport, production of solid waste, organic effluents among others, a total of CO2eq emissions of 20 tons. In this initiative, emissions compensation will be based on the reforestation of native species from the Brazilian Atlantic Forest in the context of a socio-environmental project called Guapiaçu Ecological Reserve - REGUA (https://www.regua.org.b).

357

Geochemistry and Microbiology in the Eastern Antarctic Continental Shelf

Adrianna Matthews¹, Jacob Perez¹, Gage Coon¹, Katie Howland², Hannah Nygaard², Sophie Flaherty², Dr Deric Learman², Dr Andrew Steen¹

¹University of Tennessee, Knoxville, USA. ²Central Michigan University, Mount Pleasant, USA

Abstract

The heterotrophic processes that govern microbial carbon cycling on the Eastern Antarctic continental shelf have received little attention using modern geomicrobiological techniques, owing to infrequent sampling. To better understand this sediment geomicrobiology, we collected sediment cores from 10 sites from the R/V Nathaniel B. Palmer in 2023. To characterize porewater geochemistry, we measured porewater sulfate, sulfide, and methane. To understand the structure and activity of the microbial community, we also measured cell abundance, microbial community structure via 16s rRNA gene sequences, metabolic potential via shotgun metagenome libraries, and microbial activity via metabolite measurements, metabolite flux experiments, and extracellular enzyme assays. In coordination with these analyses, we are developing a new methodology to capture active enzymes from these sediments, in an effort to enhance our understanding of the microbiology in this environment from an enzymatic perspective. Coupled with metagenomic data, this new method may prove useful for capturing active enzymes from uncultured organisms. Together, these results will shed light on the pathways by which organic carbon is metabolized by microbes in the Eastern Antarctic continental shelf.

358

Antarctic Microorganisms: Probiotic Approach for Wastewater Treatment

Mr. Jeffrey Vargas Perez

CIBE - ESPOL, Guayaquil, Ecuador

Abstract

Given the significant generation of domestic wastewater from anthropogenic activities in Antarctica, it is crucial to explore efficient treatment methods. While approximately 63% of research stations employ biological treatment, their effectiveness is hampered by the low temperatures prevalent in the region. Most systems rely on mesophilic microorganisms, which are optimal at 20°C, limiting their efficiency in colder climates. This study explores the capability of Antarctic microorganisms to degrade organic matter under freezing conditions, with implications for environmental remediation.

Eleven isolates were previously isolated from sediment samples around the Brazilian Scientific Station Comandante Ferraz on King George Island from the XXVI Ecuadorian Antarctic Expedition in 2023. Enzymatic activity was evaluated using media containing organic substrates: starch, casein, vegetable oil, and pigment, followed by incubation at 20°C for 15 days. Enzymatic activity was quantified using spectrophotometric methods.

Among them, isolates labeled as CIBE_B26.2, CIBE_A24.6, and CIBE_A5.1 exhibited the highest enzymatic activity in amylase (1.45 mg ml-1), lipase (119.33 U ml-1), and protease (0.908 µg ml-1) respectively. Notably, CIBE_C6 demonstrated the capacity to decolorize 80% of the pigment, exhibiting ligninolytic enzymatic activity that enhances the phenolic compound degradation.

Moreover, the selected microorganisms exhibited multiple enzymatic activities across a wide temperature range (4 to 70°C), making them promising candidates for reducing Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) in synthetic wastewater in aerobic conditions.

This research unveils a promising avenue for exploiting Antarctic microorganisms as novel biocatalysts for environmental remediation. By harnessing their cold-adapted enzymatic machinery, these microorganisms offer a sustainable solution for addressing organic pollution in cold regions, with potential global implications for wastewater treatment and industrial processes.

360

Enhancing the Recording and Analysis Process of Antarctic Soundscapes to Study Anthropogenic Impacts on Antarctica.

Electrical Engineer Maria Espinosa, Electrical Engineer Emiliano Acevedo, Electrical Engineer Ilana Stolovas

UdelaR, Montevideo, Uruguay

Abstract

Over the past years, the project 'Antarctic Soundscapes’ (AS) has been assessing the anthropogenic impacts on the Antarctica soundscape through audio recordings. This ongoing endeavor involves the periodic sampling of recordings according to a customizable schedule, deploying a variety of AudioMoth recorders strategically positioned across multiple areas of King George Island over summer campaigns.

One of the challenges faced by the AS project lies in the limited field autonomy of recording devices, approximately 15-20 days, due to using three AA non-rechargeable batteries. As a result, the recorders need to be periodically replaced, which is a costly and time-consuming task due to the remote location of the devices and the need for specialized personnel to execute the replacements.

To overcome these limitations, we developed an autonomous audio recording system by enhancing the AudioMoth recorder with a solar panel, rechargeable battery, and controller. Components including the Adafruit bq24074 USB/DC/Solar charger, a 6V 1W Adafruit solar panel, and a 3.7V 2500mAh Li-Po battery were procured for implementation. The prototype underwent testing during the 2022-2023 Antarctic Summer Campaign and revealed promising results: it ran continuously for 84 days without replacement, a significant improvement over original devices. Despite encountering memory constraints in the campaign's final days, the prototype showed the potential to exceed expectations regarding energetical autonomy.

After the summer campaign, the AS project has yet another significant challenge: analyzing the generated recordings, which amount to a duration of 2 months' worth of audio. This represents a major issue for the project, as they rely on human personnel to manually analyze the recordings. To tackle this issue, we implemented a machine learning-powered audio tagging system. This system takes Antarctic soundscape recordings and identifies anthropogenic sources such as helicopters, vehicles, and boats within them.

362

Individual and temporal variation in the trophic ecology of a far-ranging Southern Ocean marine predator, the Antarctic fur seal

Noémie Friscourt¹, Dr Andrea Walters¹, Dr. Simon Wotherspoon², Dr. Mia Wege³, Dr. W. Chris Oosthuizen⁴, Prof. P. J. Nico de Bruyn³, Dr Christopher Chapman⁵, Prof Mary-Anne Lea^1,6

¹Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia. ²Australian Antarctic Division, Kingston, Australia. ³Mammal Research Institute, University of Pretoria, Pretoria, South Africa. ⁴Centre for Statistics in Ecology, University of Cape Town, Cape Town, South Africa. ⁵Commonwealth Scientific and Industrial Research Organisation Environment, Hobart, Australia. ⁶ARC Australian Centre for Excellence in Antarctic Science, University of Tasmania, Hobart, Australia

Abstract

Ecological studies often consider individuals within a population as ecologically equivalent. However, substantial individual variation in diet and foraging strategies can exist within populations, even those typically regarded as generalists. Such variations among individuals may enhance individual foraging efficiency, reduce intraspecific competition, and provide fitness advantages that ultimately will increase the resilience of the population. Assessing temporal changes and stability of niche variation is important as temporal consistency of individual specialization will have implications for the population’s ecology, dynamics and evolution. Here, we investigated individual and population level variation in the trophic ecology of adult female Antarctic fur seals (Arctocephalus gazella, AFS) from Marion Island (Southern Indian Ocean) over a decadal timescale (2008-2018). Stable isotope values of whiskers enabled the construction of an isotopic time series that could be related to foraging locations as inferred from geolocating sensors carried by female AFS during the non-breeding period. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope data revealed a generalist population, with individuals ranging from extreme specialists to generalists in their habitat and resource use. We identified four distinct main foraging strategies within the population, each characterized by a unique combination of trophic resource and habitat preferences, which could be explained by intrinsic (e.g. morphology, genetic legacy) and extrinsic factors (e.g. intra- and inter-specific competition). Most females sampled over multiple years (n=39) showed a high degree of fidelity to foraging strategies (61% in habitat use and 74% in diet), suggesting that female AFS may consistently employ specific foraging behaviours to limit the potential costs of shifting foraging areas. Finally, our analysis revealed interannual fluctuations in the population’s isotopic niche, potentially linked to changes in environmental conditions, highlighting the population's adaptability to ecosystem changes. Understanding how individuals respond to spatiotemporal variability in prey availability carries significant ecological, evolutionary, and conservation implications for this population.

364

Profile analysis of overwintering physicians in the Japanese Antarctic Research Expedition (JARE): insights for future medical preparedness

Associate Professor Shinji Otani^1,2, Director Giichiro Ohno³, Lecturer Atsushi Ikeda⁴, Professor Satoshi Imura²

¹Tottori University, Yonago, Japan. ²National Institute of Polar Research, Tachikawa, Japan. ³Hokkaido Teuri clinic, Haboro, Japan. ⁴University of Tsukuba, Tsukuba, Japan

Abstract

【Objective】 The Japanese Antarctic Research Expedition (JARE) typically includes two physicians who overwinter. While physicians are selected through public recruitment, most are clinical practitioners working in hospitals, with limited time for specialized training before departing for Antarctica. It is noteworthy that at the primary Japanese observation base, Syowa Station, emergency evacuations are nearly impossible for approximately nine months. Therefore, we aimed to compile and analyze the profiles of physicians who participated in JARE as overwintering team members to inform future medical arrangements in Antarctica.

【Methods】 We targeted physicians who overwintered in Antarctica from 1956 to 2023 (JARE 1 to 65) and collected data on age, gender, specialty, and pre-expedition workplace.

【Results】 A total of 120 physicians overwintered in Antarctica up to JARE 65 in 2023, with nearly two physicians per expedition since JARE 22. There were 14 female physicians, and in recent years, mixed-gender pairs have been more common. The mean age was 39.2 years (range: 25–59 years), with ages around 45 years from JARE 50 onwards. Physicians' specialties were distributed as follows: surgery 50%, internal medicine 14%, anesthesiology 8%, emergency medicine 7%, and orthopedic surgery 5%. The primary workplaces of physicians at the time of selection were university hospitals (51%), public hospitals (32%), and private hospitals (15%).

【Discussion】 According to past disease statistics at Japanese Antarctic bases, surgical and orthopedic conditions accounted for 45%, while internal medicine conditions accounted for 21%, suggesting a proportional presence of physicians for various illnesses. In recent years, there has been a trend towards higher average ages among expedition members, and it has become more common for members with underlying medical conditions to overwinter. Physicians overwintering in Antarctica are expected to be proficient not only in disease management but also in preventive medicine.

365

Cosmogenic ¹⁴C demonstrates thickening, rather than thinning, of the East Antarctic Ice Sheet interior during the Last Glacial Maximum

Cari Rand¹, Doctor Richard Jones¹, Doctor Andrew Mackintosh¹, Doctor Brent Goehring², Doctor Kat Lilly³

¹Monash University, Melbourne, Australia. ²Los Alamos National Laboratory, Los Alamos, USA. ³RSC, Dunedin, New Zealand

Abstract

Our knowledge of how the Antarctic ice sheet has responded to Quaternary climate change relies on a combination of geological and data and ice-sheet modeling. At the Last Glacial Maximum (LGM), observations and models suggest that increased ice-sheet volume was accommodated by thickening near the coast and grounding-line advance towards the continental-shelf edge. In the interior, however, the ice sheet maintained a relatively stable thickness until present, with ice-core evidence even suggesting thinner ice relative to today. Geological reconstructions of past ice thickness in Antarctica mostly come from surface-exposure data using cosmogenic nuclides that are relatively insensitive to prior exposure on the order of tens of thousands of years, providing potentially inaccurate records of LGM ice thickness, particularly in the ice sheet interior. Here we present a surface-exposure chronology of past ice-thickness change derived from in situ cosmogenic ¹⁴C dating of bedrock and erratic cobbles from a nunatak in the Grove Mountains in East Antarctica, 380 km inland from the Antarctic coast. Samples saturated with ¹⁴C at 1912 m a.s.l. indicate that the nunatak summit was exposed during the LGM, while unsaturated samples indicate that thinning subsequently occurred, with some (25-45%) post-LGM thinning recorded at ~15-11 ka and most (55-75%) recorded during the Holocene. These results imply that at least part of the interior East Antarctic Ice Sheet (EAIS) was thicker at the LGM, followed by gradual ice-sheet thinning initiating at ~15 ka, coincident with records of dated grounding-line retreat on the continental shelf. Ice-sheet models that do not account for this thickness change may inaccurately characterize the post-LGM geometry of the EAIS and underestimate its contributions to deglacial sea-level rise.

368

An investigation of the effects of varying grain sizes, density, porosity and temperature on the permeability of synthetic firn and snowpack ice cores.

Mr Kamvelihle Tabata

University of Cape Town, Cape Town, South Africa

Abstract

This research paper investigates the effects of varying grain sizes, density, porosity, and temperature on the permeability of synthetic firn and snowpack ice cores. The ice cores are prepared in sub-zero conditions in the polar engineering laboratory to simulate the engineering properties of the firn and snowpack ice cores in Antarctica. The primary focus of this investigation is to enhance our understanding of hydrological processes within the firn and snowpack resulting from the influence of meltwater and rainwater infiltration. To achieve this, a seepage experiment has been devised to explore the properties of the firn and snowpack, considering the stratigraphy. This involves examining different compaction levels of the shelf, as well as variations in grain size, density, and porosity. Here, we introduce the initial set of findings from the concept testing phase of the designed experiment. From the results, the permeability of firn and snowpack samples, with identical compaction rates but varying ice grain size (1.18mm, 2mm, and 4mm), increases with larger grain sizes. Another noteworthy observation is that, with an increase in compaction rate for a given grain size, there is a corresponding rise in density. This increase in density leads to a reduction in permeability, attributed to the diminished porosity and pore volume.

369

Piping Warmth, Building Resilience: Exploring Community Infrastructure Integration from Yakutsk's Heating Pipes to Antarctica's Icy Frontiers

Dr Maiia Sivtseva

London Metropolitan University, London, United Kingdom

Abstract

Yakutsk, renowned for its extreme cold climate, relies on an overground heating pipes system to provide essential warmth to its residents and infrastructure. This exploratory paper investigates the potential of repurposing this existing infrastructure to build additional community infrastructure, enhancing the city's liveability and resilience. Beginning with an overview of Yakutsk's heating pipes system and its challenges, the paper delves into various types of community infrastructure that could be integrated, such as walkways, green spaces, and cultural facilities. The benefits, including improved quality of life and economic development, are highlighted. Drawing parallels, the paper explores how similar concepts could be applied to Antarctica, considering the unique challenges and opportunities of the region. Lessons from Yakutsk's exploration are extrapolated to propose innovative approaches for enhancing research stations and settlements in Antarctica, emphasizing stakeholder engagement and collaboration. The paper concludes by underscoring the importance of further research and planning to realize a more resilient and sustainable urban environment in Yakutsk, while also inspiring creative solutions for infrastructure development in Antarctica.

373

Sub-Antarctic Island Chronicles: From Huts to Bytes

Dr Marike Stander, Dr Elizabeth Rudolph

University of the Free State, Bloemfontein, South Africa

Abstract

The Sub-Antarctic Marion Island boasts a distinct cultural heritage within its field hut books, chronicling daily life since the early 1990s. Despite their potential significance to South Africa's cultural heritage, these hardcopy records face the imminent threat of deterioration. Through collaborative efforts spanning geography, data management, image studies, archiving, and literature across three institutions, this project endeavours to cultivate expertise and foster innovative methodologies while aligning with the Antarctic and Southern Ocean Strategy's capacity-building objectives. The content of these hut books promises rich insights into the social dynamics, environmental conditions, and personal experiences of Marion Island's inhabitants, benefitting both natural and social sciences. The methodological approach involves navigating the harsh conditions of remote field huts, necessitating an innovative approach to ensure high-quality digitisation, metadata management, and secure archiving. The project underscores the need for ethical considerations in digitising personal accounts, proposing strategies to protect privacy while allowing future access. The preservation of these records is seen as a crucial step toward safeguarding South Africa's heritage, adhering to national legislation and emphasising the cultural significance of historical documentation. This project aims to collect, digitise, and store these valuable hut book entries, as well as propose ways, either by embargo or other privatisation clauses, in which the content of these books might be accessed in the future by researchers whilst ensuring ethical practices, protection of privacy and the conservation of historical heritage. We encourage inputs from conference attendees and the public, acknowledging the potential enrichment of the research through diverse perspectives and insights.

378

Virome analysis of hydrocarbon-contaminated soils on King George Island, Antarctic

Caroline Oliveira¹, Deborah Leite², Lucy Seldin¹, Diogo Jurelevicius¹

¹Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ²Federal Technological University of Paraná (UTFPR) Campus Dois Vizinhos, Dois Vizinhos, Brazil

Abstract

Due to human influence in polar regions, Antarctic has areas contaminated by oil, causing an impact on soil microbial diversity. Here, metagenomic data obtained by Illumina MiSeq shotgun sequencing was used to evaluate the composition of bacteria and viruses in soils with high-(A, B, and C) and low-oil contamination (D and E) from King George Island, Antarctic. Bacterial and viral taxonomic analysis was performed using Kaiju, whereas MetaSPAdes and Virsorter were used to assemble metagenomic contigs and to identify potential bacteriophages, respectively. The Proteobacteria phylum was predominant in all soils, while the most abundant bacterial genus was Rugosibacter (5.8%) in soil A, Lutibacter (8.1%) in soil B, Polaromonas (16.8%) in soil C, Rugosibacter (2.7%) in soil D, and Rugosibacter (4.9%) in soil E. In total, 263 viral contigs were assembled from Antarctic soils, of which 82% are of unknown family, otherwise, the main viral family identified was Casjensviridae, composed of virulent phages. Soil B had the highest number of viral contigs (143) and soil E the lowest (9). Soils D and E had the highest rates of non-bacterial viruses, like giant viruses and viruses capable of infecting algae, while soil B had the highest total diversity of bacteriophages. Soils B and C contain high concentrations of phages capable of infecting bacteria described as hydrocarbon degraders, such as Microbacterium, Gordonia, Arthrobacter, and Mycobacterium. Additionally, 50%, 52%, 54%, 71%, and 0% are temperate viruses in soils A, B, C, D, and E respectively, while 50%, 48%, 46%, 29%, and 100% are virulent. Thus, this study demonstrates the effect of contamination on bacterial composition and virome diversity in Antarctic soils.

379

Subsidizing the Deep Blue: A Country-specific Analysis of Southern Ocean Fishery Subsidies

Vasco Chavez-Molina¹, Cassandra Brooks¹, Elizabeth Francis¹, Rashid Sumaila², Louise Teh², Steven Miller¹

¹University of Colorado Boulder, Boulder, USA. ²University of British Columbia, Vancouver, Canada

Abstract

The issue of fishery subsidies as crucial funding mechanisms for high seas fisheries has garnered significant global attention. Recent studies reveal that without substantial government subsidies, over 50% of international fishing grounds would be economically unviable. Among these fisheries, the Southern Ocean stands out for its remoteness, isolation, and hazardous fishing conditions. Comprising 10% of the global ocean, the Southern Ocean is managed by the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR). Every season, 12-14 countries actively fish in the CCAMLR Convention Area for Patagonian and Antarctic Toothfish as well as Antarctic Krill. These countries include Australia, Chile, China, France, Japan, Korea, New Zealand, Norway, Russia, South Africa, Spain, Ukraine, United Kingdom, and Uruguay, and their operations have direct effects on the region's biodiversity. Through interviews with Southern Ocean fishery representatives, government officials from the Ministry of Fisheries, and expert researchers across 12 countries, we offer a detailed examination of the current state of Southern Ocean fishery subsidies. While previous studies have identified countries benefiting from fishery subsidies, and that subsidies lead to overfishing, concrete subsidy data remains scarce for most Southern Ocean fisheries. Our analysis provides a country-specific evaluation of subsidies in Southern Ocean fisheries, shedding light on the intricate economics that underpin these fisheries' profitability. While our study shows that only a few Southern Ocean fisheries are receiving direct subsidies, and not enough to significantly impact their profitability margins, each fishery interviewed revealed the highly complex and unique operations required for them to maximize their profits. Our research focuses on the nuanced and unique nature of Southern Ocean fishery operations, which are often shaped by individual country policies, geographical locations, and economic partnerships.

380

Characterization of prophages in Rummeliibacillus stabekisii PP9, isolated from King George Island, Antarctica

Caroline Oliveira, Igor Taveira, Fernanda Abreu, Anderson Cabral, Rodolfo Paranhos, Lucy Seldin, Diogo Jurelevicius

Federal University of Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Rummeliibacillus is a genus consisting of Gram-positive, spore-forming, flagellated bacteria. These bacteria have been isolated from different geographic locations, but only a few species have been described, and their ecological role is little known. The objective of this study was to evaluate the presence of bacteriophages in Rummelibacillus stabekisii PP9, isolated from the soil of King George Island, Antarctica, to understand the ecological interactions of this species in polar regions. For this study, 4 genomes of the species R. stabekisii, isolated from different environments, were downloaded from the NCBI database (DSM 25578 from US soil, NBRC 104870 from Japanese soil, PP9 from Antarctic soil and MER TA13 from soil of a spacecraft). The phaster program was used to identify phage sequences in bacterial genomes, which were then manually inspected using BLAST for confirmation. Subsequently, these viral sequences were aligned in order to identify similarities between the phages found in each strain. In the results, it was observed that only PP9, isolated from Antarctica, had complete phages, since the sequences found contained integrase and essential structural proteins. In total, 3 intact phage genomes and 1 incomplete, or degenerate, genome were found in PP9, while the other strains only presented incomplete phages. Of the three complete phages, all are temperate and only phage 1 has a known family, belonging to the Herelleviridae family. The 3 regions of complete PP9 phages presented integrase and 2 of these phages also presented lysine, indicating lytic potential. Through the alignment it was possible to observe that an incomplete phage from DSM25578 had 100% similarity with an incomplete phage from NBRC104870 and 44% similarity with an incomplete phage from PP9. The study of the Antarctic region and its microorganisms is an opportunity to research microbial ecological interaction, since only PP9 presented intact prophages.

381

Multidisciplinary approach to determine the influence of human pressure on nearshore Antarctic fish

Lisette Zenteno-Devaud¹, Gabriela Aguirre-Martínez², Isabel Aguirre³, Fernanda Vargas^4,5, Konrad Górski^6,7, Melissa Rebolledo⁷, Daniel Ramírez⁸, Ignacio Garrido^7,9,10,11, Paulina Bruning^9,10, Jorge Acevedo¹, Iván Hinojosa^6,12,13,14

¹Centro de Estudios del Cuaternario Fuego-Patagonia y Antártica, Punta Arenas, Chile. ²Universidad de Arturo Prat, Iquique, Chile. ³Universidad Austral de Chile, Valdivia, Chile. ⁴Estación Costera de Investigaciones Marinas (ECIM), Las Cruces, Pontificia Universidad Católica de Chile, Santiago, China. ⁵Millennium Nucleus for Ecology and Conservation of Temperate Mesophotic Reef Ecosystems (NUTME), Pontificia Universidad Católica de Chile, Santiago, Chile. ⁶Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Concepción, Chile. ⁷Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ⁸Instituto Antártico Chileno, Punta Arenas, Chile. ⁹Takuvik, Quebec Ocean, Department of Biology, Université Laval, Québec, Canada. ¹⁰Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ¹¹Laboratorio Costero Calfuco (LCC), Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. ¹²Center for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile. ¹³Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción, Concepción, Chile. ¹⁴Centro de Investigación Oceanográfica COPAS COASTAL, Universidad de Concepción, Concepción, Chile

Abstract

Early warning signals in organisms can be found through studying the effects of contaminant exposure on different human pressure levels. In the present study, concentrations of cadmium (Cd), lead (Pb), iron (Fe), zinc (Zn), and copper (Cu) together with hematological and morphological parameters were measured in three coastal fish species (Notothenia coriiceps, Notothenia rossii, and Harpagifer antarcticus) collected in South Bay and Fildes Bay, Western Antarctic Peninsula. Furthermore, we assessed isotopic niche widths among fish populations to better understand their trophic ecology in these environments. Overall, the metal concentrations in fish were ranked in the following order: N. coriiceps and N. rossii = Fe > Zn > Cu > Cd > Pb; H. antarcticus = Zn> Fe> Cu > Pb > Cd. In particular, N. coriiceps from Fildes Bay displayed high concentrations of Fe and Cu, while those from South Bay had higher concentrations of Cd. All fish from South Bay had higher zinc levels than specimens from Fildes Bay. These findings could be attributed to: (1) Fe: loss of continental ice mass; (2) Cu: increases in contaminant sources (e.g., antifouling paint); (3) Cd: the presence of upwelling areas; and (4) Zn: the presence of upwelling areas combined with inputs from other sources, such as galvanized steel or penguin guano. Effects such as biomagnification of Fe and shifts in hematological variables caused by Pb and Zn suggest that metal concentrations may affect coastal Antarctic fish. Additionally, the niche width expansion of N. coriiceps and H. antarcticus could be attributed to suboptimal environmental conditions in Fildes Bay. Based on a multidisciplinary approach, our findings suggest that early warning signals in coastal Antarctic fish may be linked to increased metal bioavailability in sediments and water column as a result of climate change and increased human pressure.

Funding: FONDECYT Nº319045 and FONDECYT Nº11180466.

382

Differences in annual snow accumulation between the Antarctic Peninsula and West Antarctica in the 1979–2008 period

José Mauro Dalla Rosa¹, Jefferson Simões^1,2, Francisco Aquino¹, Pedro Reis¹, Franciele Schwanck¹, Mariusz Potocki², Paul Mayewski², Andrei Kurbatov², Ronaldo Bernardo¹, Isaias Thoen¹, Jeffrey Auger¹, Sharron Sneed², Ricardo Jaña³

¹Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Climate Change Institute, University of Maine, Orono, USA. ³Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

We investigated net annual snow accumulation differences between the Antarctic Peninsula (AP) and the West Antarctic Ice Sheet (WAIS) over 29 years (1979–2008 CE). We use two ice cores, one from the AP, Detroit Plateau (64°05' S, 59°38' W; 1937 m altitude) and another from the WAIS, Mount Johns (79°55' S, 94°23' W; 2100 m altitude). We compared them with results from published ice core records, two from the AP, Bruce Plateau (66°03' S, 64º07' W; 1976 m altitude) and Gomez (73.59°S, 70.36°W, 1400 m altitude) and one from the WAIS, Ferrigno (74°34’ S, 86°54’ W; 1354 m altitude). The mean annual net snow accumulation rate during the period on the AP was 2.44 ± 0.63 m a⁻¹in water equivalent (Detroit Plateau), 2.40 ± 0.52 m a⁻¹(Bruce Plateau), and 0.99 ± 0.24 m a⁻¹(Gomez, 1979–2006). On the WAIS, the annual net snow accumulation rate was 0.23 ± 0.05 m a⁻¹(Mount Johns) and 0.41 ± 0.09 m a⁻¹(Ferrigno). We used the ERA5 reanalysis to investigate the behavior of atmospheric circulation in the South Pacific Ocean during the same period and its role in snow precipitation variability in the regions of the five ice core sites. A positive Southern Annular Mode (SAM) trend in recent decades, strengthened after 1993, has deepened the Amundsen Sea low (ASL) and has increased cyclonic activity and precipitation, especially in the AP (+0.036 m a⁻¹ at Detroit Plateau; +0.032 m a⁻¹ at Bruce Plateau; +0.015 m a^-1 at Gomez). However, the Ferrigno and Mount Johns regions did not show statistically significant trends in the WAIS. Their greater distance from the coast, and the displacement of the ASL toward the east may explain the different precipitation behaviors at the two WAIS sites.

383

The Polar Rock Repository: a means for studying biodiversity across Antarctic landscapes

Dr Anne Grunow, Dr. Jamey Stutz, Dr. Erica Maletic

The Ohio State University, Columbus, USA

Abstract

The Polar Rock Repository (PRR) contains sample collections, metadata, and media relevant to understanding changes in biodiversity across many polar landscapes. Ice sheet change and climate warming over time have altered the size of biological refuges around the continent. Currently, the Antarctic ice sheet is losing mass and with more rock becoming exposed, refugia are expected to proliferate. However, the role of polar biota on chemical and physical weathering remains largely unknown. The broad geographic scope of PRR samples and metadata containing lichen, moss, cyanobacteria, etc., could be potential bio-monitors indicating shifting habitats related to environmental and climate change.  

The PRR is a National Science Foundation funded facility that provides online access to >61,000 rock samples, glacial deposits, terrestrial drill cores, and marine dredge samples from Antarctica and surrounding regions. The PRR online database allows multi-field searchable criteria useful to biodiversity studies including plants, algae, other life, regolith, radioactivity (to help identify micro niches), as well as photos and videos of outcrops and landscapes. Samples can be ordered directly from our website (prr.osu.edu) for research (destructive research techniques permitted). The PRR has also created a media archive that can provide information about surface and habitat features (algal ponds, streams with plants, etc.) reflecting recent change.   

With easy access to a diverse collection of samples, metadata, and images, the PRR offers a unique resource for studying terrestrial biodiversity and ecosystems across Antarctica’s landscapes.  

384

Glaciers retreat in Greenwich, Livingston, Robert e Snow Islands, Antarctica, in last decades

Graduate student Danielle Dall Amaria Soffiatti¹, Ph.D Kátia Kellem da Rosa¹, Undergraduate Nicholas Becker Pires Pi¹, M.e Júlia Lopes Lorenz¹, Ph.D Carina Petsch², Ph.D Filipe Gaudie Ley Lindau¹, Ph.D Jefferson Cardia Simões¹, Ph.D Francisco Eliseu Aquino¹

¹Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Universidade Federal de Santa Maria, Santa Maria, Brazil

Abstract

This study investigates the variation of glacial coverage in ice caps and ice fields on the Greenwich, Livingston, Robert, and Snow Islands, Antarctic Maritime, between 1956 and 2023. Glacier extension mapping was based on visual interpretation of the Landsat 4, 7 and 8 optical images and normalized difference indexes combination. The selected images were recorded during the ablation season. The dates analyzed vary depending on the island due to the scope of the images. The REMA 8 digital elevation model was applied to the islands' geomorphometric analysis. Annual series of air and sea surface temperatures were analyzed. The Livingston and Greenwich islands are the largest in glacial coverage, with maximum elevations of 1,688.3 and 625 meters, respectively. The glacial coverage decreased by 16.9% from 1956 to 2023. The total area loss was 209.95 ± 0.113 km² from 1956 to 2023. The retreat rate was 3.1 km²/year in the 1956-2023 period. Snow Island, with shallow bathymetry near glacial margins and land-terminating ice-fronts, exhibited the smallest values of the retreat rate in the study area. The glacial coverage of Livingston Island has decreased significantly (18%, equivalent to 153.2 ± 0.113 km²) in 1956-2021, with an area loss of approximately 2.4 km² per year, representing the highest values in the study area. The changes in glacial coverage of the Robert and Greenwich islands were the most substantial in the 1989-2023 period. The Greenwich Island glacial area loss for 2014-2023 (0.8 km²/year) was higher than the last period (1989-2014). The changes in islands were related to glaciers' response to the regional climatic change. Sectors with marine-terminating glaciers, associated with high bathymetric amplitudes, exhibited more significant variations compared to other sectors of the islands, contributing to the evolution of fjord-type bays.

386

Long-term observations of ice-wedge thermal regime and frost-cracking conditions in Northern Victoria Land Antarctica

Francesco Grifoni¹, Mauro Guglielmin¹, Rossana Raffi², Simone Sega³, Riccardo Bono⁴

¹Insubria University, Varese, Italy. ²Sapienza University of Rome, Roma, Italy. ³Italian National Fire Rescue Service, Rome, Italy. ⁴ENEA UTA, Roma, Italy

Abstract

A long-term monitoring program on ice-wedge (IWs) thermal regime has been undertaken since 2004 at three sites located between 72°S and 74°S in Northern Victoria Land. The selected sites, Baker Rocks (11m a.s.l.), Boomerang Glacier (874m a.s.l.), and Mount Jackman (1326m a.s.l.) are placed on an altitudinal transect of 1315 meters. Here we present the results of the monitoring of the active layer thickness (ALT), temperature of the permafrost table and we evaluate the potential for IWs fracturing due to thermal contraction and how this is influenced by climatic conditions along an altitudinal transect. The mean annual ground surface (MAGST) and the mean annual air temperatures (MAAT) were at Baker Rocks (-15.4°C; -15.6°C), Boomerang Glacier (-19.9°C; -20.9°C), and Mount Jackman (-20.6°C; -21.6°C) respectively. Winter air temperatures exceeded the GST, indicating the absence of significant snow cover, while summer air temperatures were below the GST as expected. The thickness of the active layer i.e., the depth of the IWs top ranged between 0.45m and 0.5m at Baker Rocks, between 0.12m and 0.35m at Boomerang Glacier and between 0m and 0.35m at Mount Jackman with average values of 0.47m, 0.28m and 0.19m, respectively. The mean annual IWs top temperature was -14.3°C for Baker Rocks, -19.8°C for Boomerang Glacier and -20.5°C for Mount Jackman. The depth and temperature of the IWs top decreases with altitude and showing a stochastic trend at all sites. ALT appears to be principally related to summer air and ground temperatures at Mount Jackman and Boomerang sites (R²> 0.5). Preliminary results confirm that the thermal contraction of IWs occurred every winter in all the sites continuously since 2004.

389

MANUEL SEÑORET, ISMAEL GAJARDO, AND ALBERTO CHANDLER: CONTRIBUTIONS FOR A RENEWED CHILEAN ANTARCTIC HISTORY

Dr Mauricio Jara

Universidad de Playa Ancha, Valparaiso, Chile. Centro de Estudios Hemisfericos y Polares, Viña del Mar, Chile

Abstract

At the turn of the twentieth century, Manuel Señoret, Ismael Gajardo, and Alberto Chandler, as members of the Chilean Navy, accomplished significant tasks that contributed to the country’s Antarctic interests and goals. Their actions, mostly unknown until now, can demonstrate the early connection between Navy officers and the frozen continent affairs, as well as Chile’s role in that immense geographical space.

Señoret was responsible for the establishment of a small settlement on the northeastern coast of Navarino Island, which was intended to connect Southern Chile with the Antarctic Peninsula (1892). In addition, he informed the Chilean government about foreign expeditions to the South Shetland Islands, which was understood as an intrusion into the national territory. For his part, Gajardo -finding himself in command of the Huemul cutter and anchored in Ushuaia- was able to contact the crew of the Antarctic which had returned from Snow Hill for supplies after leaving the scientists of the expedition led by Nordenskjöld (1902). Finally, Chandler stood out for being part of the Argentine Antarctic expedition that, in 1903, rescued the above-mentioned scientists. The tasks accomplished by these three Navy officers demonstrate not only their capacity to accomplish the orders and instructions given by their authorities, but also their eagerness to protect and enforce Chile’s sovereignty rights in the territory of Magallanes and the southern seas.

Making visible and integrating these three naval figures in a renewed interpretation of the Chilean Antarctic history is the central purpose of this poster proposal. The main sources are official documents (Gobernación de Magallanes Archive), press materials from Punta Arenas, the Navy Hydrographic Yearbook, and Revista de Marina.

392

Distribution of chrysophycean stomatocyst in surface sediments around the Antarctic Peninsula, Weddell and Scotia Seas

Dr M. Angeles Barcena¹, Dr. Andres S. Rigual¹, Dr. Enrique Isla²

¹University of Salamanca, Salamanca, Spain. ²ICM-CSIC, Barcelona, Spain

Abstract

The importance of a better understanding the distribution of marine chrysophycean stomatocysts in the polar environment is twofold: on the one hand, to better understand their relationship with both sea and continental ice and, on the other hand, their possible use as an indicator of past sea ice and/or ice shelf extent conditions.

In this work, a total of 113 surface sediment samples from the western Atlantic sector of the Southern Ocean, recovered in different oceanographic campaigns (ANT- 8611, FRUELA, ANT-XXIII/8, ANT-XXVII/3, ANT-XXIX/3 and ANT-XXIX/9) have been used in this study. Preliminary data indicate that abundances of up to 1.71 x 10⁶ statocyst/g of dry sediment have been recorded around the South Orkney Islands, coinciding with the limit of the summer sea-ice. The lowest values are found in the easternmost sector of the Weddell Sea, up to two orders of magnitude lower than in South Orkney. Intermediate values are registered in the Antarctic Peninsula and Bransfield Strait.

Twenty-eight morphotypes have been characterized, 16 of which could be related to species described in the literature, the rest are documented but could not be identified. Another point worth noting is the recurrent distribution of Litheusphaerella spectabilis and Archaeomonas areolata, both in their two forms/varieties, throughout the study area, although L. spectabilis seems to have a preference for the proximity of the Larsen and Filchner ice shelves, A. areolata, although present, is not as well represented in the ice shelves proximity. The diatom/chrysophycean cysts index seems to indicate a negative relationship between productivity (based on diatom abundance) and stomatocyst presence.

This study is being extended to the Ross Sea, with a battery of 50 samples currently available for this purpose.

393

Microplastics in top predators’ scats in Crepin Point and surroundings during summer 2020

Luis Santillán¹, Gabriel De-la-Torre¹, Ana Forero López²

¹Universidad San Ignacio de Loyola (USIL), Grupo de Investigación BIOMAS, Lima, Peru. ²Instituto Argentino de Oceanografía (IADO), Buenos Aires, Argentina

Abstract

Antarctica is a continent dedicated to research and conservation, and USIL carried out a project about MP in the ecosystem during the XXVII Peruvian Antarctic expedition in January 2020. We collected 38 scats, 23 of penguins and 15 of seals along the coast of McKellar inlet close to the Peruvian Antarctic Station Macchu Pichu (ECAMP). Species determination was not fully possible, however, all the penguins in the area were of the Pygoscelis genus (mainly Gentoo penguin P. papua). The Seal more frequent species was the Weddell seal Leptonychotes weddellii, a small group of scats of elephant seal Mirounga leonina were collected from Punta Thomas. The scat was removed with a steel spatula and put in a glass jar. The sample processing and analysis was in the laboratories of USIL in Peru. The organic material in scats was digested with KOH 10% for 5 days, thereafter, the solution was filtered in Whatman filters of 40µ. The filters were observed with optical microscopic 10X magnification to determine the potential MP those were chemical analyzed with a micro-Fourier-transformed infrared spectroscopy (μ-FTIR) at UADO laboratory. Potential MP in penguins and seals were 29 and 28 respectively. In penguins, 24% of MP were confirmed as plastic polymers, PET (14%), acrylic resin (7%) and polycrylic acid (3%). In seals, 10% MP were plastic polymers, all were PET, none of elephant seal scats presented MP. The other MP were identified as cellulose and among these, 18% would be of anthropogenic origin in seals and 35% in penguins. Our findings report the occurrence of MP in top predators hauling in Almirantazgo bay, mainly in McKellar inlet. MP in top predators are evidence that the pollution by plastics in Antarctica occurs in the whole ecosystem, despite being a remote area far from big cities in the continents.

394

Opportunistic records of large cetaceans in McKellar inlet during summer 2020, 2023 and 2024

Luis Santillán, Gabriel De-la-Torre, Miguel Mucha

Universidad San Ignacio de Loyola (USIL), Grupo de Investigación BIOMAS, Lima, Peru

Abstract

Large whales were registered opportunistically during summer in McKellar inlet in Almirantazgo bay, King George island. Records were obtained in January 2020, February 2023 and January 2024. All the sightings were opportunistically obtained in the absence of a dedicated observation effort. Three species were positively identified, Humpback whale (Megaptera novaeangliae), Minke whale (Balaenoptera sp), and Sei whale (Balenoptera borealis). Humpback whale was by far the most frequent species, 15 individuals were observed in January 2020, among them, 5 were confirmed as calves. In February 2023 there was only one specimen and in 2024 were 12 individuals with 2 calves. About sei whales, there were two individuals in January 2020. Minke whale species determination was not possible since there was not enough evidence to confirm if they would be B. acutorostratus or B. bonaerensis. Minke whale was observed in February 2023 and January 2024, one specimen each time. Humpback whales usually enter the inlet and remain there, mainly adults with calves. Minke whales also enter the inlet but seems that they do not remain there. Sei whale were observed close to McKellar inlet but they did not swim there, they mainly remained in the Almirantazgo bay. Large cetaceans are good indicators of well environmental conditions and Almirantazgo bay and McKellar inlet offer a calm habitat for shelter, resting and care for calves. This is the first insight of large whale occurrence in McKellar inlet and provide a detailed record of species use and importance.

398

Detection of extreme events of seawater temperatures on Fildes Bay (2019-2023), Antarctica and its relationship with atmospheric rivers

Lorena Rebolledo¹, Heitor Evangelista^2,3, Sérgio J Gonçalves Jr^2,3, Carla Ximena Salinas¹

¹Chilean Antarctic Institute (INACH), Punta Arenas, Chile. ²Laboratory of Radioecology and Global Changes (LARAMG), Rio de Janeiro, Brazil. ³State University (UERJ), Rio de Janeiro, Brazil

Abstract

Marine heatwaves are extreme values of seawater temperature lasting at least 5 days upper the 90% percentile of a climatic series. Here, we studied records of seawater temperature using a mini-ctd star-oddi sensor anchored at 9.5m at Fildes Bay, Islote Shoa, Antarctica, with events of atmospheric rivers (AR). AR are relatively long, narrow regions in the atmosphere where there is a concentrated flow of water vapor. They are responsible for transporting large amounts of moisture from the tropics to higher latitudes. Here, the data on seawater temperature recovered from the mini CTD sensor were processed using the package heatwave R. Reanalysis of atmospheric models were run for determined integrated water vapor contents (IWT), Integrated vapor transport (IVT) and by for detection of AR. The marine heatwaves events were classified in terms of its duration, intensity. We detected a total of 15 events of an increase of sea water temperature upper the threshold of the 90 percentile. The duration of marine heatwaves ranged between 5 to 17 days (January 2020-January 2023). The most intense and lasting events were detected during mainly summer and autumn seasons. During 6^th to 11^th February, 2020, a big heatwaves related to AR impacted the Shetlands Islands and the Antarctic Peninsula, with atmospheric temperatures that reaches 18 °C at Esperanza, (Argentina Base), and 7 °C at Frei station (Chile Base) on 8^th February, 2020. The increases in seawater temperature were detected on Fildes Bay 11^th to 16^th February, 2020, three days before the peak in atmospheric temperature registered on King Jorge Islands, Frei meteorological automatic station (DMC, code number 950001).

400

Advances in summertime observations of dissolved organic carbon along the northern Antarctic Peninsula

Raquel Avelina^1,2,3, Leticia C. da Cunha^1,2,3,4, Rodrigo Kerr^3,5, Claudia Hamacher^1,6, Cássia de O. Farias^1,6, Mauricio M. Mata⁵

¹Programa de Pós-Graduação em Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ²Laboratório de Oceanografia Química, Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ³Brazilian Ocean Acidification Network, Rio Grande, Brazil. ⁴Rede Clima, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, Brazil. ⁵Laboratório de Estudos dos Oceanos e Clima, Universidade Federal do Rio Grande, Rio Grande, Brazil. ⁶Laboratório de Geoquímica Orgânica Marinha, Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Dissolved organic carbon (DOC) is an important component of the carbon cycle in different sections of the Southern Ocean. However, there are still significant gaps in understanding the role of DOC in polar environments, due to the spatiotemporal sampling limitations. To better understand the role of DOC in the Southern Ocean biogeochemical cycles, the Brazilian High Latitude Oceanography Group (GOAL) has carried out a continuous effort of DOC summertime observations, in the northern Antarctic Peninsula (NAP) since 2015. Here, we present an overview of recent advances in the study of DOC distributions along the NAP, between 2015 and 2019. We collected 894 DOC samples across 205 oceanographic stations. Samples were measured as non-purgeable organic carbon. DOC excess (∆DOC) was calculated by subtracting surface and deep DOC concentrations. DOC concentrations in the NAP ranged from 33.0 to 162.0 μmol kg^–1, with a median of 49.2 μmol kg^–1. Surface DOC accumulation and vertical export occurred especially in the Gerlache Strait, the Bellingshausen Sea and, near the land portions of the Bransfield Strait, producing a maximum ∆DOC of 20 μmol kg^–1, compared to the DOC available in NAP deep waters (~44 μmol kg^–1). Minimum DOC concentrations (< 45 μmol kg^–1) could be observed at the surface in the eastern basin of the Bransfield Strait, with concentrations increasing towards the Weddell Sea. The wide DOC spatial coverage and the continuity of annual summer sampling have made it possible to identify both significant differences in DOC distributions among the different NAP regions, interannual differences considering the data collected in the same regions. Furthermore, El Niño - Southern Oscillation and Southern Annular Mode impacted DOC distribution in Bransfield Strait between 2015 and 2016. Thus, DOC can be considered an important proxy to evaluate the coupling between physical, biogeochemical and climate processes over time.

401

Rock-Soil relationship and its influence on soil edaphic characteristics at Ulu Peninsula, James Ross, Antarctica.

Mr Heitor Palma¹, Mr Daniel Krum¹, Mr Marcos Paulo Tomaz¹, Mr Ícaro Miranda¹, Mrs Mariana Lima¹, Dr Rafael Siqueira¹, Dr Fernando Villela², Dr Cláudio Eduardo Lana³, Dr Márcio Francelino¹, Dr Carlos Schaefer¹

¹University Federal of Viçosa, Viçosa, Brazil. ²University of São Paulo, São Paulo, Brazil. ³University Federal of Ouro Preto, Ouro Preto, Brazil

Abstract

The Ulu Peninsula, located on James Ross Island, Weddell Sea, Antarctica, is characterized by great geological and pedological diversity. The objective of this work is to verify the influence of the parent material on the physical and chemical characteristics of soils in the Ulu Peninsula. Four different topographic compartments supported by three different lithologies were examined: conglomerates with finer intercalations of the Whisk Bay Formation (WB), basaltic tuffs and hyaloclastites of the Terrapin Hill Formation (TH), and volcanic groups of James Ross Island (JRVG), regarding two soil profiles described and sampled in each one. WB is a Cretaceous sedimentary formation, while TH and JRVG are volcanic formations corresponding to the Pliocene and Upper Miocene epochs respectively, with the former composed of volcanic ashes and the latter of hialoclastic breccias intercalated with basalt. Soil samples were analyzed for pH, Na, electrical conductivity (EC) and texture, in addition to principal component analysis (PCA) and descriptive statistics which were used for interpretation of the results. PCA explained 87.3% of the data variation, with Sand, pH and Na positively correlated with each other and negatively correlated with silt, EC, and clay. PCA also showed proximity between profiles of the same geology, indicating an intrinsic relationship between soil and rock in soil formation. In WB profiles, sand was the most explanatory variable, while for TH it was pH and Na, and for JRVG, clay and EC were the most ones. The silt fraction does not exert strong influence in any of the lithologies under study. It is concluded that the geological substrate directly influences the characteristics of soils in this northern part of the Semi-arid Antarctica, with other environmental factors such as relief and proximity to the sea also playing a role in their differentiation.

402

Increased spring dissolved organic carbon and nitrogen production and DOC/DON ratio decrease along the Atlantic sector of the Southern Ocean

Raquel Avelina^1,2,3,4, Leticia C. da Cunha^1,2,3,5, Kai-Uwe Ludwichowski⁴, Boris P. Koch⁴, Christine Klaas⁴

¹Programa de Pós-Graduação em Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ²Laboratório de Oceanografia Química, Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ³Brazilian Ocean Acidification Network, Rio Grande, Brazil. ⁴Alfred-Wegener-Institut Helmholtz Zentrum für Polar - und Meeresforschung, Bremerhaven, Germany. ⁵Rede Clima, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, Brazil

Abstract

Dissolved organic matter (DOM) is a component of the ocean biological pump, containing fractions of dissolved organic carbon (DOC), nitrogen (DON), and other biologically relevant elements. The role of DOM in marine systems is important for linking the carbon and nutrient cycles. Here we evaluate the seasonal DOC and DON distributions and the DOC/DON ratio in the upper 300 m of the Atlantic sector of the Southern Ocean between 2004 and 2022. We used the dataset collected aboard the RV Polarstern on cruises under umbrella of the Alfred Wegener Institute, Germany, during austral summer 2012, winter/early spring 2013 and spring 2022 as well as datasets from international repositories collected in the spring 2004 and summers 2005, 2010 and 2014. DOC and total dissolved nitrogen (TDN) were analyzed with a TOC-L® Series Shimadzu. DON was calculated by subtracting TDN and dissolved inorganic nitrogen concentrations. The austral spring presented the highest median concentrations of DOC and DON respectively, 49.8 µmol kg^–1 and 5.1 µmol kg^–1 and the lowest DOC/DON ratio (11.2). The DOC, DON and the DOC/DON ratio in spring were also statistically different from median results in winter (45.2 µmol kg^–1, 3.4 µmol kg^–1 and 14.3) and summer (45.8 µmol kg^–1, 3.6 µmol kg^–1 and 13.1). However, there were no differences between winter and summer conditions. The highest DOC and DON concentrations confirmed that spring is important for the DOM production and accumulation in the euphotic zone, due to the availability of light and nutrients for phytoplankton. We also corroborate studies in other sectors of the Southern Ocean showing that DOM deviates from the Redfield C/N ratio for plankton production (6.6). However, the release of nitrogen-rich organic matter by zooplankton may contribute to the DOC/DON ratio decrease in spring.

405

Phytoplankton diversity across Southern Ocean fronts: Integrating DNA metabarcoding with pigment signatures.

Dr Antonia Cristi¹, Mark Gall¹, Dr Mikel Latasa², Dr Andrés Gutiérrez-Rodríguez²

¹National Institute of Water and Atmospheric research, Wellington, New Zealand. ²Instituto Español de Oceanografía, Xixon/Gijon, Spain

Abstract

Quantifying the taxonomic composition of phytoplankton is crucial to understanding the biological carbon pump and predicting ecosystem response to climate change. Various methods are used, each with distinct advantages and limitations. High-Performance Liquid Chromatography (HPLC) pigment analysis is a chemotaxonomic tool providing classification to the class level. However, nutrient availability and light exposure influence pigment and cellular carbon concentration and therefore, accuracy. DNA metabarcoding of conserved genes (18S rRNA) details taxonomic composition down to the strain level. However, quantitative estimates of cell abundance or carbon biomass are limited by gene copy number variability and rely on curated databases to assign taxonomy. Here, we use a combined analysis of datasets collected from two New Zealand to Ross Sea Antarctic voyages to improve discriminatory power across contrasting oceanographic water masses of the southwest Pacific sector of the Southern Ocean. Surface samples (5 m) were collected from an underway system every 6 hours from subtropical waters southwest of New Zealand (40°S) to the Ross Sea (75°S). Preliminary analysis shows a consistent biogeographic pattern for diatoms, with their relative contribution to the community increasing south of the Polar Front. Distribution patterns drawn by each method differ for dinoflagellate and prymnesiophyte abundance. DNA metabarcoding determines a greater abundance of dinoflagellates than HPLC pigment analysis across all fronts, potentially illustrating a bias in gene copy number associated with this class. Conversely, prymnesiophyte abundance is significantly higher in the pigment analysis. Overall, there is a positive correlation between the main taxonomic groups across methods. Additional statistical analysis incorporating microscopy datasets is anticipated to enhance discriminatory power and accuracy. Improved knowledge of surface phytoplankton taxonomic composition and dynamics across oceanographic fronts is expected to enhance the accuracy of satellite remote sensing net primary productivity models used to estimate carbon flux.

408

Field and satellite observations of Crane Glacier, Antarctic Peninsula following the 2022 fast-ice break-out

Naomi Ochwat¹, Liliana Margonari^2,3,4, Dr. Sebastián Marinsek⁵, Dr. Ted Scambos¹

¹University of Colorado Boulder, Boulder, USA. ²Universidad de Buenos Aires, Buenos Aires, Argentina. ³instituto Antartico Argentino, Buenos Aires, Argentina. ⁴Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina. ⁵Instituto Antartico Argentino, Buenos Aires, Argentina

Abstract

Crane Glacier experienced rapid ice tongue break-up and retreat, acceleration, and thinning following a break-out of decade-old landfast sea ice in January 2022. In February 2024, a field team visited to the glacier and an adjacent outcrop and set up two single-frequency GPS units on the glacier surface and a precision GPS NetRS system on an adjacent rock outcrop near the calving front (‘the Balcony’). We also installed an Iridium-linked camera (NuPoint systems Aeremis), two time-lapse cameras (Harbortronics) observing the calving front, and an Iridium-linked weather station that reports temperature and humidity. The GPS units on the glacier surface were set 4km and 6km upstream of the calving front, on a suture zone near the centerline that had relatively few crevasses based on Worldview-3 images from January 30th 2024. Initial GPS results (26 February — 11 March 2024) for both the upper and lower GPS are 2.91±0.2 md^-1. Calving characteristics of the ice front from satellite images and on-site photography suggest the majority of the February 2024 terminus is grounded, with only toppled icebergs in the upper fjord and a sloping ice front consistent with listric fracturing. Cliff height in the year prior to the field visit (February 2023) was 85 m above the sea surface; we await updated ICESat 2 data on the 2024 cliff height. Continued monitoring of the ice front and flow speed will indicate seasonal or tide-cycle variations in flow speed, details of calving style, calving front retreat, and melange stability.

410

Climate change and its range effects on sheathbills: Modeling the present and future potential distribution of the genus Chionis.

Catalina Escobar A.^1,2,3, Dr. Luis R. Pertierra^2,4, Dr. Pablo C. Guerrero^1,2,3

¹Universidad de Concepción, Concepción, Chile. ²Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Concepción, Chile. ³Instituto de Ecología y Biodiversidad (IEB), Concepción, Chile. ⁴Museo Nacional de Ciencias Naturales (MNCN), Madrid, Spain

Abstract

Changes in temperature, wind, and precipitation have occurred rapidly in the Antarctic region over the last 60 years, having significant impacts on the ecosystem and causing changes in the physical environment that directly affect Antarctic wildlife. For birds, climate is very relevant to population dynamics, having effects on reproductive performance and variation in migration and distribution. Chionis (Aves: Chionidae) is a genus that includes two species of native breeding birds, Antarctic sheathbill C. albus and C. minor, which could be affected by climate change, altering the availability of suitable habitats. The objective of our study was to evaluate the impact of climate change on the potential distribution of sheathbills species, which have a wide geographical range in Antarctic Peninsula and sub-Antarctic regions. Our aim was to model their current distribution using both terrestrial and marine bioclimatic variables, and project this distribution under future climate change scenarios. For this, we used data obtained from CHELSA (scenarios SSP126 and SSP585 for 2011-2040 and 2041-2070 period) and Bio-Oracle (scenarios RCP2.6 and RCP8.5 for 2040-2050). Our hypothesis posits that there will be an expansion in the distribution range of C. albus, a species with a broad geographical presence, and a contraction in the distribution of narrowly endemic C. minor. This anticipated change is attributed to the island habitat of C. minor, which is expected to be more vulnerable under the forecasted climate scenarios. The results of the species distribution models indicated that for C. albus, more habitats will become available, primarily in the Antarctic Peninsula and Tierra del Fuego. For C. minor, the available habitat in the future tends to decrease on the sub-Antarctic islands. Our findings confirm the high extinction risks for C. minor due to its limited habitat availability on sub-Antarctic islands, underscoring the need for targeted conservation efforts for this species.

414

Relation of the genesis of Transantarctic Mountains, rift structures of East Antarctica and subglacial Lake Vostok

Professor Alexey Markov^1,2, Valery Lukin^3,4

¹China University of Geosciences, School of Geophysics and Information Technology, Beijing, China. ²Jilin University, Polar Research Center, Changchun, China. ³Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation. ⁴St. Petersburg State University, St. Petersburg, Russian Federation

Abstract

The authors propose a hypothesis of the relation of genesis of Transantarctic Mountains, rift structures of East Antarctica and Lake Vostok. The Transantarctic Mountains may have a right-side shift deformation of the Earth’s crust the source of which is a large transform fracture at the boundary of the Indo-Australian and Pacific tectonic plates. Using a principle of deformation ellipsoid for the right-side shift, the main axis of which the direction of Transantarctic Mountains was chosen, we have made a conclusion that extension of Lake Vostok complies with the direction of the antithetic shift. This fact is in agreement with presence of the left-side shift deformation of the Earth’s crust at rift genesis of Lake Vostok. Thus, the Transantarctic Mountains can be a source of deformations of rift genesis of Lake Vostok and similar structures of East Antarctica.

415

Cultural and Genomic Characterization of Rahnella sp. CCG E3-1, an Endophytic Bacterium of Deschampsia antarctica

Lucas Borque¹, Marcos Esteso¹, Catalina Victoria Basile Dazzi^2,1,3, Juan Orlowski^1,2, Walter Patricio Mac Cormack^3,1, Sofie Thijs⁴, Jaco Vangronsveld⁴, Lucas Adolfo Mauro Ruberto^3,2,1, Francisco Massot^3,1

¹Instituto de Nanobiotecnología (NANOBIOTEC, UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina. ³Instituto Antártico Argentino, Buenos Aires, Argentina. ⁴CMK - Centre for Environmental Sciences (Hasselt University), Hasselt, Belgium

Abstract

Hydrocarbon pollution in Antarctica requires the development of effective removal tools to restore the environment. New approaches should allow to accelerate the response time, completely remove the contaminant, and preferably restore the original conditions of the polluted soil. The use of plant species and their associated microorganisms, known as phytoremediation, seems to be a promising technology. In this work, we carried out the cultural and genomic characterization of the D. antarctica endophytic and psychrotolerant bacteria Rahnella sp. CCG E3-1. This Gammaproteobacteria showed exceptional tolerance to Antarctic diesel mixture (≥ 10,000 mg Kg-1) and the ability to degrade it. Its growth was explored in different laboratory culture media and at different temperatures, obtaining respective specific growth rates and maximum growth temperatures. It was discovered that the CCG E3-1 strain is a significant producer of the auxin indole-3-acetic acid (IAA), a plant growth-promoting phytohormone. The IAA production curve was studied at different temperatures and times. Finally, a general characterization of the genome of the CCG E3-1 strain was carried out, particularly focusing on genes associated with hydrocarbon degradation and plant growth promotion. The results showed that R. sp. CCG E3-1 has an optimal growth temperature at 25ºC, with appreciable growth rates observed between 10 and 30ºC. Furthermore, the highest growth was observed in the formulated liquid R2A modified medium. IAA production occurred from the second day of cultivation at 22.5ºC, while at 10ºC, it occurred from the third day. Genes related to hydrocarbon tolerance, the structure of the operon associated with IAA production, and other genes of interest in the plant-microorganism association were identified in the genome. Finally, these results encourage us to deepen the characterization of the strain and to consider carrying out plant-microorganism interaction studies to carry out future field trials.

418

Tonian-Cryogenian orogenic signatures from the interior of Princess Elizabeth Land, East Antarctica: clues from morainal deposits

Mr. Akash Kumar Pandey¹, Dr. Mayuri Pandey¹, Dr. Rashmi Gupta¹, Dr. Devsamridhi Arora², Prof. Naresh Chand Pant^3,4, Mr. Mohd. Sadiq⁵

¹Department of Geology, Banras Hindu University, varanasi, India. ²National Centre of Experimental Mineralogy and Petrology, University of Allahabad, Prayagraj, India. ³National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences, Goa, India. ⁴Department of Geology, University of Delhi, New Delhi, India. ⁵Geological Survey of India, NCEGR, Faridabad, India

Abstract

Princess Elizabeth Land (PEL) region in East Antarctica plays a crucial role in the formation of Gondwana. Additionally, it holds concealed clues that can help unravel mysteries surrounding the evolution of the East Antarctic Craton. Thick ice-sheets pose challenges for direct access to rocks, necessitating reliance on geophysical methods such as seismic and gravity surveys for interpretation. These techniques are instrumental in identifying significant crustal boundaries like Indo- Australo- Antarctic Suture zone and subsurface features, including the intriguing Gamburtsev Subglacial Mountains (GSM), however, do not offer conclusive constraints on tectonic evolution of the terrane. Age of the GSMs remains enigmatic, with various inference methods suggesting conflicting timelines—both Grenvillian age (1000 Ma) and Pan-African age (550 Ma). Additionally, diverse extensions of IAAS have been proposed through different methodologies, further contributing to the mystery. Recently, discovery of an extensive subglacial drainage network beneath the ice sheet of PEL has provided an exciting new avenue for obtaining clues for geology of the far interior. Retracing pathways of subglacial sediment into the continent's interior holds potential to establish connections among these clues originating from beneath the ice sheet. This raises the prospect of ultimately unveiling the geological history of even most remote parts of the continent. Preliminary examination of morainal samples reveals high-grade metamorphic lithologies like paragneiss, orthogneiss, amphibolite schist, and garnet schist having almandine garnet with higher pyrope content suggesting high-pressure metamorphic belt in the interior confirming signatures of a suture. Monazite grains from paragneiss and garnet schist records 778 and 838 Ma events, providing evidence of a significant tectono-thermal event that occurred during the Tonian-Cryogenian from Neoproterozoic era. The recent reporting and documentation of this event prompt discussions regarding the connection between GSM and IAAS and the correlation of this event with the Grenvillian and Pan-African orogenies.

420

New insights into the Antarctic Circumpolar Current evolution across the Drake Passage.

PhD Candidate África Gamisel-Muzás¹, Doctor Carlota Escutia¹, Doctor Fernando Bohoyo²

¹Earth Sciences Andalusian Institute (IACT) - Spanish Council for Scientific Research (CSIC), Granada, Spain. ²Geological Survey of Spain (IGME) - Spanish Council for Scientific Research (CSIC), Tres Cantos, Spain

Abstract

The Antarctic Circumpolar Current (ACC) stands as the strongest, fastest and deepest current in the global oceanic circulation with a profound influence on contemporary global climate. However, our knowledge about the tectonic and climatic mechanisms in control of its onset and evolution is still limited. The Drake and the Tasmanian Passages opening enabled the establishment of the ACC as we know it (Kennett, 1977). A recent study by Evangelinos et al. (2024) has shown that the ACC acquired its contemporary characteristics approximately 14-10 Ma ago in the Atlantic, Indian and western Pacific. However, the evolution of the ACC across the Drake Passage remains a subject of study. This is due to the complex interplay between tectonic (i.e., complete oceanic opening, uplift of Shackleton Fracture Zone, and opening of the Bransfield Strait) and climatic (i.e., development of the Antarctic Peninsula Ice Sheet) factors in the development of the ACC.

The PENANT 2024 expedition collected data from an area spanning from the Hero to the Shackleton Fractures, covering an extensive area from the abyssal plain to the shelf of the South Shetland Islands. Approximately 2000 kilometers of multi-channel seismic reflection profiles were acquired, facilitating a preliminary interpretation of the sedimentary fill above the acoustic basement.

We observe an increasing influence of bottom currents deposition with development of large mounds above a seismic reflector of uncertain age. In addition, there is evidence for gravity flow deposits associated to extensive canyon-channel systems in the marginal areas. By analyzing the stacking patterns and spatial distribution of these deposits, we infer the influence of tectonic and climatic controls in the evolution of the ACC through the Drake Passage.

This research is supported by Grants PDI2021-126495NB-C31/C32 and PhD PRE2022-103074 from MCIN/AEI /10.13039/501100011033 / FEDER, UE.

421

Impact of climate change on East Antarctic interior temperature extremes

¹Nagoya University, Nagoya, Japan. ²Kitami Institute of Technology, Kitami, Japan. ³National Institute of Polar Research, Tachikawa, Japan. ⁴University of Wisconsin–Madison, Madison, USA

Abstract

Extreme events are predicted to become more frequent and more severe as global warming continues. Here we present the first analysis of extreme surface air temperatures (SAT) in the interior of East Antarctica. We compiled a new daily mean SAT dataset for the last 30 years from the historical records of the automatic weather stations (AWSs) at three sites (Mizuho, Relay Station, and Dome Fuji) in the interior of Dronning Maud Land in East Antarctica. Temperature measurements by AWS were biased warm due to insufficient ventilation during austral summer, so that radiation errors were removed using a regression model. For each month, we examined the frequency distributions of daily mean temperatures and identified the extreme warm and cold days when the daily temperature was above the 90^th percentile and below the 10^th percentile of the temperature distribution. Three stations showed a statistically significant warming trend over the last three decades. The warming trend was not observed in all months, but there was a clear warming in the months of January, October, and November, with the largest warming in October. Interestingly, these months correspond to the months in which the number of extremely warm days has statistically increased over the last three decades. We found that the inter-annual variability in monthly temperature was matched to the changes in the number of extremely warm days. These suggest that more frequent occurrence of extreme temperature events is attributed to the positive trend in annual mean temperature in the interior region of East Antarctica.

422

Soil Thermal Regime on Vega Island: A Four-Year Climate Investigation

Doctor Rafael Siqueira¹, Doctor Roberto Michel², Doctor Márcio Francelino¹, Doctor Guilherme Correa³, Doctor Carlos Schaefer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Estadual de Santa Cruz, Ilhéus, Brazil. ³Universidade Federal de Uberlândia, Uberlândia, Brazil

Abstract

Polar regions exhibit an acute sensitivity to climate fluctuations. Recent projections outlining the consequences of substantial environmental shifts, underscore the urgency of anticipating changes in polar zones. The northeastern sector of the Antarctic Peninsula is no exception and is witnessing relevant transformations. These include widespread glacier retreat, the fragmentation of the Larsen Ice Shelf, and a 1.5°C surge in air temperature over the past decades. Vega Island, situated in the Weddell Sea, possesses a distinct semi-arid climate. This uniqueness arises from its positioning between the warmer and more humid Maritime Antarctica and the drier, colder Continental Antarctica. The objective of this abstract is to report the results of four years (Jan 2018 to Jun 2021) of thermal monitoring of a Typic Haploturbels (63° 52’ 07’’S 57° 33’ 14’’W, 5, 10 and 50 cm) located at 120 m a.s.l.. Average air temperature was -4.83°C for the studied period, -6.09°C in 2019 and -5.70°C in 2020; soil temperature averaged 3.25°C, 3.52°C, and 3.60°C, with 2019 and 2020 presented very similar averages, 4.57°C in 2019 and 4.58°C in 2020 at 50 cm despite greater amplitude in 2020. The sum of positive daily averages was 199.16°C days, 85.93°C days and 0.32C in 2019 and 521.95°C days, 271.36°C days and 22.55°C days in 2020 at 5, 10 and 50 cm. Freeze degree days picture a milder winter in 2020, negative daily averages summed 1934.34°C days, 1857.83°C days and 1679.49°C days in 2019 and 2052.15°C days, 1912.78°C days and 1706.11°C days in 2020. Estimated active layer depth was 52cm in 2019 and 64cm in 2020. The soil thermal regime at Vega Island shows a uniform temperature pattern at different layers, responding quickly to air temperature variations.

433

First results of atmospheric air pollution measurements in Thala Hills, Enderby Land, East Antarctica

Vladimir Ryzhikov^1,2, Alexey Gaydashov¹, Vadim Radzivill³, Olga Krukowskaya², Alena Aucharova², Julia Ramankevich², Natallia Bykava²

¹Republican Center of Polar Research, National Academy of Sciences of Belarus, Minsk, Belarus. ²Institute for Nature Management, National Academy of Sciences of Belarus, Minsk, Belarus. ³R-NOX, Minsk, Belarus

Abstract

High-latitude regions (Antarctica and its vicinity) are of interest for studying the behavior of pollutant concentrations in the atmospheric air for several reasons. Anthropogenic sources and emissions are rare here. They originate from a limited number of sources and are relatively fairly well-documented. A significant portion of pollutant concentrations are determined by natural processes, synoptic transport, and descent from upper layers. Additionally, this region is recognized as a climate-sensitive area. Data on substance concentrations, many of which contribute to climate formation in these high latitudes, are of interest for evaluating the background levels and trends of O3 on a hemispheric scale.

Land based data on air pollutant concentrations are limited, especially for East Antarctica. In many cases impact on air and air quality researched in indirect way by content of deposited pollutants in organic and non-organic substances. The investigation of individual pollutant concentrations, especially ozone, is the most common. To date, no air quality research has been conducted in the coastal area of Enderby Land within the framework of the Belarusian Antarctic Expedition.

The purpose is representing the first results of measurements of CO, NO, NO₂, O₃, PM₁₀, PM_2.5concentrations. Measurements were conducted since the January 2024 by gas and aerosol analyzer AirNode made by Belarusian R-NOX company. AirNode belongs to the class of compact near-reference stations and can be installed in hard-to-reach areas. The implementation of the company's unique technologies ensures the acquisition of reliable data in any climatic conditions. Joint analysis of measured concentrations, meteorological conditions, and station activity has been completed. Obtained data can be used for checking fact impacts of activity, verification modeling results.

434

The hazardous meteorological phenomena in the area of the Belarusian Antarctic station Mount Vechernyaya, Thala Hills, East Antarctica

Academician Vladimir Loginov¹, Vladimir Ryzhikov^2,1, Alexey Gaydashov², Olga Olga Krukowskaya¹, Alena Aucharova¹, Julia Ramankevich¹, Natallia Bykava¹

¹Institute for Nature Management, National Academy of Sciences of Belarus, Minsk, Belarus. ²Republican Center of Polar Research, National Academy of Sciences of Belarus, Minsk, Belarus

Abstract

The main hazardous meteorological phenomena (HMP) in the considered part of East Antarctica are associated with high wind speeds (strong wind, storm, hurricane), intense precipitation, and reduced visibility (fog, blizzard) to a lesser extent. In the conditions of modern climate warming in the high latitudes of the Southern Hemisphere, due to the strengthening of turbulent heat fluxes from ocean into the atmosphere an intensified shift in the period of observing maximum wind speeds to autumn, whereas previously it was observed in January–April.

According to the long term data from the Molodezhnaya Antarctic Research Station (1973–1999), the probability of the occurrence of HMP exhibits pronounced seasonal dynamics. The frequency of high wind speeds is minimal in January, then increases to a maximum in April–May, and gradually decreases by December. On average, from March to July, over 3/4 of the recorded winds fall into the HMP category, with 14–21% classified as strong winds, 40–47% as, and 33–46% as hurricanes. Throughout the year, around half of the high-speed winds are storm winds, and in April–June, the proportion of hurricane winds also increases to over 40%.

An analysis of the meteorological data from the Belarusian Antarctic Station Mount Vechernyaya for January–April and November–December 2012–2021, has shown that the distribution of high-speed wind recurrence aligns with the data from the Molodezhnaya Antarctic Research Station for 1973–1999: there is an increase from the minimum value in January to a maximum in April, followed by a decrease in December. For January–March, there is a comparable proportion of storm winds compared to the previous period and a lower proportion of hurricane winds.

Data from the year-round automatic weather station for years 2022–2023 show lower average monthly values of high-speed wind recurrence throughout the year.

436

Quantifying microplastics in fjords along the Western Antarctic Peninsula

Ms. Tristyn Garza¹, Dr. David Barnes², Dr. James Scourse³, Dr. Justine Whitaker⁴, Dr. Alexis Janosik⁵

¹University of Florida, Gainsville, USA. ²British Antarctic Survey, Cambridge, United Kingdom. ³University of Exeter, Cornwall, United Kingdom. ⁴Nicholls State University, Thibodaux, USA. ⁵University of West Florida, Pensacola, USA

Abstract

Microplastics are ubiquitous around the world. Microplastics have been documented around the Southern Ocean, in coastal sediments and in Antarctic marine organisms, however microplastics data for Antarctic waters remain scarce. Microplastics concentrations were characterized from fjord habitats on the Western Antarctic Peninsula where most glaciers are rapidly retreating. Water samples were collected from 2017 to 2020 from surface and benthos, vacuum-filtered, quantified to determine the classification of microplastic, color, and size. Micro-FTIR spectrophotometry was utilized to confirm chemical composition. Comparisons over time and location were made for average microplastic per liter. Despite the new emergent youth and remoteness of these habitats, it was determined that all fjord habitats had microplastics present each year sampled and increased from 2017 to 2020 in each fjord. Despite physical ‘barriers’ such as the Antarctic Circumpolar Current (and particularly its strongest jet, the Polar Front), microplastics are clearly present and increasing in even recent habitats.

437

Adaptation strategies of giant viruses to low-temperature marine ecosystems

Marianne Buscaglia^1,2,3,4, José Luis Iriarte⁵, Frederik Schulz², Beatriz Díez^1,3,4

¹Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile. ²DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. ³Millennium Institute Center for Genome Regulation (CGR), Santiago, Chile. ⁴Center for Climate and Resilience Research (CR)2, Universidad de Chile, Santiago, Chile. ⁵Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Punta Arenas, Chile

Abstract

Microbes in marine ecosystems have evolved their gene content to thrive successfully in the cold. While this process has been reasonably well studied in bacteria and selected eukaryotes, less is known about the impact of cold environments on the genomes of viruses that infect eukaryotes. Here, we analyzed cold adaptations in giant viruses from austral marine environments and compared them with their Arctic and temperate counterparts. We recovered 150 giant virus metagenome-assembled genomes (GVMAGs) from 61 newly sequenced metagenomes and metaviromes from sub-Antarctic Patagonian fjords and Antarctic seawater samples. When analyzing our unique data set alongside Antarctic and Arctic GVMAGs already deposited in the Global Ocean Eukaryotic Viral (GOEV) database, we found that Antarctic and Arctic giant viruses predominantly inhabit sub-10ºC environments, featuring a high proportion (even higher in the Antarctic region) of unique phylotypes in each ecosystem. In contrast, giant viruses in Patagonian fjords were subject to broader temperature ranges and showed a lower degree of endemicity. However, despite differences in their distribution, giant viruses inhabiting low-temperature marine ecosystems evolved genomic cold-adaptation strategies that led to changes in genetic functions and amino acid frequencies that ultimately affect both gene content and protein structure. Such changes seem to be absent in their mesophilic counterparts. The uniqueness of these cold-adapted marine giant viruses may now be threatened by climate change, leading to a potential reduction in their biodiversity

438

Unraveling long-term trends in ionospheric F2-layer on high-latitude stations

Ph.D. student Trinidad Duran^1,2, Ph.D. student Yamila Melendi^1,2,3, Dr. Fernando Buezas^1,2, Dr. Ana G. Elias^4,5

¹Instituto de Física del Sur (CONICET), Bahía Blanca, Argentina. ²Departamento de Física, Universidad Nacional del Sur, Bahía Blanca, Argentina. ³Tucumán Space Weather Center, Tucumán, Argentina. ⁴Laboratorio de Ionosfera, Atmosfera Neutra y Magnetosfera (LIANM), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Tucumán, Argentina. ⁵INFINOA (CONICET), Tucumán, Argentina

Abstract

Long-term trends in the ionosphere, particularly in the F2 region, have garnered increasing interest since 1989, focusing on their relevance to space weather and radio signal propagation research. However, accurately attributing these trends, notably for the critical frequency foF2, remains controversial due to methodological challenges and identifying potential sources such as greenhouse gas concentrations and natural forcing. The influence of Earth's magnetic field and geomagnetic activity, which vary over the solar cycle and exhibit long-term variations, may be particularly significant in high-latitude regions. Changes in both of these forcings impact the upper atmosphere, including the ionosphere-thermosphere system, potentially causing long-term trends in atmospheric parameters like the height of the F2 layer peak (hmF2) and the maximum electron concentration estimated by foF2. This study addresses these concerns by analyzing foF2 data collected at high latitude stations, spanning from 1960 and covering at least four solar cycles, to understand how trends vary throughout the day and across seasons. By shedding light on these ionospheric trends and their underlying mechanisms, this research contributes to our understanding of climate change's effects on the Earth's atmosphere, particularly in regions sensitive to geomagnetic activity. Additionally, it enhances our comprehension of space weather conditions, aiding in the interpretation and response to fluctuations in ionospheric dynamics. It also provides a climatological description which is essential for space weather studies.

441

Lack of variation in macroalgal nutritive quality but significant variation in macroalgal input into coastal food webs along a seasonal sea ice cover gradient on the Western Antarctic Peninsula

Dr Charles Amsler¹, Dr. Katrin Iken², Dr. Aaron Galloway³, Ms. Hannah Oswalt¹, Ms. Margaret Amsler¹, Dr. James McClintock¹, Dr. Andrew Klein⁴

¹University of Alabama at Birmingham, Birmingham, AL, USA. ²University of Alaska, Fairbanks, Fairbanks, AK, USA. ³University of Oregon, Charleston, OR, USA. ⁴Texas A&M University, College Station, TX, USA

Abstract

Macroalgal forests dominate shallow hard bottom areas along the northern Western Antarctic Peninsula (WAP). We used satellite imagery to identify 14 sites differing in sea ice coverage but similar in terms of turbidity along the previously little-studied central WAP. Divers recorded replicate videos of vertical transects between 5 m and 20-40 m and collected macroalgae and macroinvertebrates for food web analyses. Fleshy macroalgal cover was strongly, negatively correlated with ice concentration. However, macroalgal species present at sites across the ice cover gradient differed little stable carbon or nitrogen isotope values, in fatty acid signatures, or in overall macroalgal protein, lipid, carbohydrate, or ash contents. Conversely, although there was no significant correlation between macroinvertebrate cover and sea ice, there were changes in their stable isotope and fatty acid signatures. Isotope values of most invertebrate feeding groups increased with higher sea ice cover, with food web length becoming shorter and consumer trophic niche width smaller. Changes were mostly associated with shifts in trophic position of lower trophic levels. Food web structure in higher ice-covered regions resembled that of more generalist feeders with a loss of specialist species, concurrent with an increased reliance on a more reworked detrital food source. We found site-level differences in the multivariate fatty acid signatures of all invertebrates, and found that ice cover was a significant driver of the fatty acid signatures of five invertebrates, including three sessile (an anemone, sponge, and tunicate) and two mobile consumers (a sea star and sea urchin) while two other sea stars and a limpet were not affected by the ice gradient. These results indicate that the more complex food webs are expected from climate change-induced sea ice decline, that impacts will vary across consumer groups, and that differences are due more to macroalgal quantity than nutritive quality.

442

Fungi in pristine Antartic soils and their biotechnological potential

Nicole Cortez¹, Dra. Vivian Burgos¹, Dra. Paola Duran², Carlos Cortés-Albayay², Dr. Cristian Paz¹

¹Laboratory of Natural Products & Drug Discovery, Center CEBIM, Department of Basic Sciences, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile. ²Biocontrol Research Laboratory, Universidad de La Frontera, Temuco, Chile

Abstract

The cold-adapted fungi isolated from pristine Antarctic soils constitutes an important understudied biological source of novel natural products with pharmaceutical potential and enzymes for biotechnological processes. During the ECA 57 in 2020, the project INACH RT-33-18 sediment samples from the South Shetland Island were collected to isolate novel Antarctic fungi producers of new bioactive molecules. Eight sampling points located on Collins Glacier, Artigas Base, Deception Island and Hanna Point were collected. A total of 65 fungi were isolated and affiliated to 13 different cultivable genus, according to the sequence similarity of their ITS region. The organic compounds produced by 27 representative members of each genus were extracted through EtOAc and evaluated in antimicrobial and cytotoxic bioassays against Prostate cancer cell lines and pathogenic yeasts. The organic extracts obtained from 7 strains showed activity against Cryptococcus neoformans and Trichosporum sp. respectively, with inhibition zone diameters between 9 and 27 mm. In addition, 14 extracts were active against the yeast Candida albicans and only 5 of them showed activity against Candida krusei. The extract of Leptobacillium leptobactrum was active against different species of pathogenic Candida, showing MICs up to 7.81 µg/mL. Also, 12 extracts showed activity against prostate cancer cell lines 22Rv-1 and C42B, highlighting to Acremonium strain with an IC₅₀ of 12.5 µg/mL for both cell lines. This strain was grown in 50 L of YM liquid media and incubated at 15°C for 21 days, obtaining 4 g of crude extract, which was fractionated and purified by chromatographic methods. Three molecules identified as Viridicatin, Cyclopenin and Cyclopenol were isolated from fractions and their cytotoxic and anti-inflammatory bioactivities still under evaluation.

443

Interactions between Antarctic ice-sheet extent and summer sea-ice variability over the last 45,000 years in the Weddell Sea-Dronning Maud Land as reconstructed from snow petrel stomach-oil deposits

Erin McClymont¹, Ewan Wakefield¹, Anna Rix¹, Michael Bentley¹, Yas Cole¹, Thale Damm-Johnsen¹, James Grecian¹, Dominic Hodgson^2,1, Eleanor Maedhbh Honan¹, Zhongxuan Li¹, Claire Penny¹, Kerry Strong¹, Mark Stevenson¹, Philippa Ascough³, Darren Groecke¹, Rus Hoelzel¹, Richard Phillips², Louise Sime², Stephen Willis¹

¹Durham University, Durham, United Kingdom. ²British Antarctic Survey, Cambridge, United Kingdom. ³Scottish Universities Environmental Research Centre, Glasgow, United Kingdom

Abstract

Constraining the nature and timing of changes to the East Antarctic ice sheet in the Weddell Sea-Dronning Maud Land sector over the last glacial cycle has been challenging, due to limited geological evidence and contrasting models of past ice sheet extents and retreat behavior. It is important to distinguish between these scenarios, because this region is also a source of Antarctic Bottom Water, which plays a crucial role in regulating global climate, and there are regions of the ice sheet which are sensitive to ocean warming.

We present a novel archive of past sea-ice conditions inferred from deposits of regurgitated snow petrel (Pagodroma nivea) stomach oils, preserved at breeding colonies extending from the Theron Mountains (30°W) to the Sør Rondane Mountains (23°E). Our deposits span Marine Isotope Stages 3 to 2, when sea ice in the Atlantic sector of the Southern Ocean reached its maximum extent (~29-22 ka), and the transition towards a reduced sea-ice extent in the Holocene. Since snow petrel occupation is contingent on the availability of bare rock, we also use the deposits to constrain the history of ice sheet thinning and retreating.

Our reconstructions of snow petrel diet use multi-proxy analysis of fatty acids, stable carbon and nitrogen isotope ratios, and elemental composition (via XRF). We identify centennial-scale variations in diet that imply regional differences in sea ice histories, indicating important ocean/ice sheet interactions over the last glacial cycle. We propose that polynyas (open waters) were present in the sea ice during Marine Isotope Stages 2 and 3, and we identify shifts to sea-ice extent through the Holocene. We explore how these changes in summer sea-ice conditions are linked to changes in ice-sheet extent and ocean/atmospheric circulation over the last ~45 ka.

447

Degradation dynamics of Antarctic macroalgae

Miss Nadia Frontier¹, Dr David Barnes¹, Dr Gabriele Stowasser¹, Dr Sebastian Rosenfeld², Dr Gloria Pereira³, Mr Darren Sleep³, Ms Helen Campbell³, Dr Lloyd Peck¹, Dr Simon Morley¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²University of magallanes, Punta Arenas, Chile. ³UK Center for Ecology and Hydrology, Lancaster, United Kingdom

Abstract

The degradation dynamics of four dominant species of Antarctic macroalgae were studied in a series of in situ experiments between 2021- 2023 at Rothera Research Station, Ryder Bay, Antarctica. Multiple metrics were collected to contribute towards understanding the time-lines and fate of C and N from degrading macroalgae. Biomass loss, photosynthetic performance (F_v/F_m,ϕPSII) and Net Primary Productivity (NPP) were measured during three in situ experiments which monitored macroalgae samples for up to 11 months. Antarctic macroalgae showed variable responses with some species loosing biomass over time whilst some species increased in biomass. This result demonstrates the ability of some species to continue fixing carbon when detached from their holdfast. Macroalgae were labelled with enriched δC¹³ and δN¹⁵ to track the flow of carbon through: invertebrate grazers living on macroalgae fronds; infauna within 2 cm of the sediment surface and into the sediment surface. Samples were analysed using isotope ratio mass spectrometry (IRMS) which revealed the consumption of some macroalgal carbon via invertebrates. While labelled tracers from the enriched macroalgae were detected within the sediments surrounding the experimental system, enrichment values did not increase with time. This suggests that the experimental macroalgae are labile and do not bioaccumulate within the sediment surface. In a soft sediment habitat survey within Ryder Bay, this study found that macroalgae detritus covers 19% of the benthic environment from 15- 18 m depth where macroalgae is dominant. Given the prominence of macroalgae detritus in benthic ecosystems, improving our understanding about the importance of macroalgae blue carbon pathways throughout the Antarctic benthos is critical so it can be better accounted for in the global carbon cycle.

453

Palynological analysis of Deschampsia antarctica (Poaceae)

Phd Luiz Antonio Costa Rodrigues^1,2, Anna Julia Ferreira Andrade de Souza³, B.Sc. Débora Freitas Isaias³, M.Sc. Fábio Leal Viana Bones⁴, Phd Paulo Eduardo Aguiar Saraiva Camara², Phd Micheline Carvalho Silva², Phd Cláudia Barbieri Ferreira Mendonça¹, Phd Vânia Gonçalves Lourenço Esteves¹

¹Museu Nacional, Rio de Janeiro, Brazil. ²Universidade de Brasília, Brasília, Brazil. ³Centro Universitário Celso Lisboa, Rio de Janeiro, Brazil. ⁴Universidade Federal de Santa Catarina, Santa Catarina, Brazil

Abstract

Palynology is the science that studies spores, pollen grains and other structures with resistant-acid organic walls, collectively called palynomorphs. Spores and pollen grains are microscopic structures involved in the reproduction of embryophyte plants. They have an external wall with wide morphological diversity, made up mainly of sporopollenin, which guarantees great resistance and makes them very stable in the environment. In the Antarctic context, the current bibliography lacks greater detail in images that can support identification in environmental matrices. In this context, the present study aimed to present the photomicrographic record and pollen description of the pollen grains of Deschampsia antarctica E. Desv. Anthers were collected pre-anthesis from specimens deposited in the Bryophyte Collection of the Botany Department of the University of Brasília. The pollen grains were acetolyzed and analyzed using an Olympus CX41 microscope with an attached camera, following usual methods in palynology. Pollen analysis allowed photomicrographs of polar and equatorial views and morphometry to be carried out. The pollen grains identified are in monads, medium, heteropolar, monoporous, with a polar diameter of 35.0 μm (27.0-39.0 μm), an equatorial diameter of 29.0 μm (25.0-36.0 μm) , circular scope and psilate exine. The results presented corroborate previous studies regarding the description of the exine and openings of pollen grains and add new measurement data. Such metric divergences may indicate environmental changes, storage conditions or plasticity of the species. The expansion of pollen studies in Antarctica can support the investigation of topics in the context of global climate change and atmospheric connections between continents.

Keywords: Palynology, Antarctica, Morphometry, Flora, Biodiversity

454

Pollen identification in samples of Antarctic Bryophyte

Phd Luiz Antonio Costa Rodrigues^1,2, B.Sc. Anna Julia Souza³, B.Sc. Debora Isaias³, Msc Fabio Bones⁴, Phd Cláudia Mendonça⁵, Phd Vânia Gonçalves Lourenço Esteves¹, Phd Micheline Silva², Phd Paulo Eduardo Camara⁶

¹Museu Nacional, Rio de Janeiro, Brazil. ²Universidade de Brasília, Brasília, Brazil. ³Celso Lisboa, Rio de Janeiro, Brazil. ⁴Universidade Federal de Santa Catarina, Santa Catarina, Brazil. ⁵Museu Nacional, Brasília, Brazil. ⁶Universidade de Brasília, Rio de Janeiro, Brazil

Abstract

Cryptogams have a relevant ecological relationship by establishing microenvironments in which animals and plants live in extreme environments. The favorable conditions for the establishment of communities in moss mats in Antarctica may be related to intrinsic factors of the extreme environment such as freezing regime and solar radiation. However, recent studies have recorded pollen input from the American Continent. The present study aimed to analyze the upper section of moss mats in order to identify pollen grains and spores present in the photosynthetic parts of this system. To carry out the analyses, samples of 3cm² moss mats collected during the Brazilian Antarctic Operation on King George Island in 2023 were processed. The samples were fractionated, washed in 10% HCL for 2h, subsequently sieved and analyzed using white light microscopy. The results revealed the presence of spores and pollen grains from the families Poaceae, Cyperaceae and Rubiaceae. The identified pollen grains and spores differ from those recorded in soil samples available in the literature. The analysis of the sediment fraction of the mats will allow us to infer a possible relationship between atmospheric pollen nutritional input and cryptofauna present in such a biological system.

Keywords: Atmosphere, Palynology, Teleconnection

456

NEW METHODOLOGY FOR SAMPLING PARTICULATE MATERIAL AND BIOAEROSOLS IN THE ANTARCTIC ENVIRONMENT

Phd Luiz Antonio Costa Rodrigues^1,2, B.Sc. Anna Julia Souza³, M.Sc Rejane Rocha⁴, M.Sc Marcelo Leal²

¹Museu Nacional, Rio de Janeiro, Brazil. ²Marinha do Brasil, Rio de Janeiro, Brazil. ³Centro Universitário Celso Lisboa, Rio de Janeiro, Brazil. ⁴Instituto Oswaldo Cruz, Rio de Janeiro, Brazil

Abstract

The participation of the Brazilian Navy in the Antarctic research allows the logistical and operational support necessary for the development of scientific activity in theRegion. This work presents the first scientific contribution of the Institute of BiomedicalResearch of the Marcílio Dias Naval Hospital for research in the area of atmospherictransport of particulate material and microorganisms. Using a prototype of anatmospheric sampler, developed at the Institute of Biomedical Research, atmosphericcollections were carried out on King George Island - Antarctica, which allowed therescue of pollen grains native to South America. The evidence was supported by modelsgenerated by the Hybrid Single-Particle Lagrangian Integrated Trajectory Platform(HYSPLIT), corroborating the effectiveness of the equipment under development and the feasibility of using pollen grains to detect the dynamics of air masses.

457

Studying seismic swarms to understand glacier dinamics

Geological engineering student Paola Julieta Cortes Cruz^1,2, PhD Marine Microbiology Patricia Valdespino³

¹Escuela Superior de Ingeniería y Arquitectura Unidad Ticomán, IPN, Mexico City, Mexico. ²Mexican Agency of Antarctic Studies, Mexico City, Mexico. ³Escuela Nacional de Ciencias de la Tierra, UNAM., Mexico City, Mexico

Abstract

The study of microseisms is taking a relevant role worldwide because the seismic swarms that occur with a relatively high frequency help researchers to identify fracture zones that are not evident in the surface. Moreover, this seismic behavior allows us to better understand geological risk zones. When seismic activity is near ice sheets, there is also risk for glacier displacement. Recently, important seismic activity has been reported in Maritime Antarctica, and related to seismic swarms in the Bransfield rift. Thus, it is necessary to study the impact of the seismicity on ice sheets displacements, particularly in this area of Antarctica, which has a vast international infrastucture and year-long human activity.

We developed an analysis of the distribution of seismic epicenters in constant microseisms of Zacatecas, Mexico. Our results showed that initial slow movements change in time due to the increasing fracture size. In addition these seisms of lesser magnitude not only cause cracks in the surface but these opening favor the storage of magmatic material by having connection with the asthenosphere and consecuently the possible ascent of molten rock to the surface. This can be berified by obtaining data on the depths of hypocenters of previous years compared to recent years, observing their decrease. It also influences the way in which their epicenters are distributed.

Our middle-term goal is to adapt this model to study the potential of ice sheet displacements in the Bransfield rift related to the occurrence of seismic activity.

458

Thermal increase and microplastics activate the transcription of genes involved in the cellular response to stress in Harpagifer antarcticus and Harpagifer bispinis.

Thermal increase and microplastics activate the transcription of genes involved in the cellular response to stress in Harpagifer antarcticus and Harpagifer bispinis Daniela Nualart^1,2,3,4, Kurt Paschke^2,5,4, Pedro Guerreiro^6,7, Stephen McCormic⁸, Christina Cheng⁹, Luis Vargas Chacoff^2,3,4

¹PhD in Aquaculture Sciences, Universidad Austral de Chile,, Puerto Montt, Chile. ²FONDAP Center for Research in Dynamics of Marine Ecosystems of High Latitudes (IDEAL), Punta Arenas, Chile. ³Institute of Marine and Limnological Sciences, Universidad Austral de Chile, Valdivia, Chile. ⁴Millennium Biodiversity Institute of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile. ⁵Institute of Aquaculture, Puerto Montt, Chile. ⁶CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal. ⁷PROPOLAR, Portuguese Polar Program,, Lisboa, Portugal. ⁸Department of Biology, University of Massachusetts, Amhers, Massachusetts, USA. ⁹Department of Evolution, Ecology and Behavior, University of Illinois, Urbana, USA

Abstract

Microplastic(MP)pollution in the Southern Ocean is an increasingly recognized problem.MP particles enter the ocean through wastewater and decomposition; they are persistent in ocean systems, sediments, surface.The existence of MP in the marine environment and its potential impact on aquatic life has become a major concern, in addition to the fact that fish can be exposed to thermal increase as a result of climate change and pollution problems due to MP such as polyvinyl chloride(PVC).However,the possible effects of both threats together are unknown, and if there are negative consequences on native species.The objective of this work was to evaluate the the cellular stress response of Harpagifer antarcticus and Harpagifer bispinis subjected to an increase in temperature and microplastics simultaneously.Adult fish of H. antarcticus were collected in Fildes Bay(Antarctica) and H. bispinis in Punta Arenas(Chile).Fish randomly distributed in tanks, one group was administered physiological saline via cannula (control),and the second group received MP-PVC200μg/L.In turn, each group was separated into two temperatures; at 2°C and 5°C for H. antarcticus and at 8°C and 12°C for H .bispinis. After 24 hours of exposure, samples of head kidney,spleen and foregut were taken and used for qPCR analysis to evaluate the transcription of genes involved in the thermal shock response(HSP70),ubiquitination(E2),S100 and HMG-1b,which could be functioning as DAMPs(damage-associated molecular pattern factor).Our results show that MP-PVC and temperature differentially modulate the expression of these genes.Both species showed an increase in the transcription of HSP-70,while the levels of S100 transcript and HMG-1b were decreased,is influenced by the thermal increase and MP exposure.Which reflects the low capacity to generate a response to the DAMPs generated by MP-PVC and temperature.Thanks to Fondap-Ideal Grant 15150003 and ANID-Millennium Science Initiative Program-CenterICM-ANID ICN2021_002(BASE)

459

From Atmosphere to Snow: Microbial Dynamics and Pollution Trends in Antarctica

Dra. Maria Estrella Alcaman-Arias^1,2, Dr. Ignacio Ramos-Tapia³, Dr. Gastón Higuera⁴, Dr. Roberto Bastías⁵, Dr. Carlos Manzano⁶, Dr. Juan Ugalde³, Dra. Zoe Fleming⁷, Dr. Camilo Rodriguez⁷

¹Centro de investigación en tecnologías para la sociedad (C+), Facultad de Ingeniería, Universidad del Desarrollo, Concepcion, Chile. ²Centro de Ciencia del Clima y la Resiliencia, CR2, Concepcion, Chile. ³Microbial Data Science Laboratory, Center for Bioinformatics and Integrative Biology, Universidad Andrés Bello, Santiago, Chile. ⁴Laboratorio de Biotecnología, INTA, Universidad de Chile, Santiago, Chile. ⁵Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. ⁶Departamento de química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile. ⁷Centro de investigación en tecnologías para la sociedad (C+), Facultad de Ingeniería, Universidad del Desarrollo, Santiago, Chile

Abstract

The snowpack, typically seen as inhospitable to life but capable of trapping microorganisms from the atmosphere, is home to dynamic microbial communities responding rapidly to environmental changes. While the atmosphere serves as the primary seeding source for snow microorganisms, it also carries pollutants that interact with them. Snowfall acts as an effective mechanism for cleansing the air of these contaminants, highlighting the potential impact of atmospheric deposition on snow contamination levels. In the Antarctic peninsula, understanding the composition of snow, airborne microbial communities, and organic pollutants like PAHs during summer remains limited. The main objective of this study was to characterize the diversity of the snow and airborne microbial community and quantify the principal PAHs in these two distant bays to evaluate differences and interactions. Chile Bay (South Shetland Islands) and South Bay (Palmer Archipelago) were monitored during January and February of 2022-2023, and the microbial community diversity was revealed through 16S rRNA gene sequencing, and passive samplers of polyurethane foam (PUF) disks were deployed to PAHs. Results showed distinct snow microbial communities between the two zones, encompassing major phylogenetic groups such as Proteobacteria, Firmicutes, Bacteroidetes, Acidobacteria, and Cyanobacteria. Airborne microbial communities showed no significant differences between zones comprising Actinobacteria, Flavobacteria and Proteobacteria. Dominant PAHs included fluoranthene, retene, and chrysene. These findings shed light on the structure of snow microbial communities and their interactions with airborne counterparts in Antarctic coastal zones while highlighting the pyrogenic origin of pollution associated with biomass burning in the region.

Funding: Fondecyt 11200413

460

Reflections on the importance of the geographical factor in the concept of biodiversity for the legal protection of biodiversity in Antarctic maritime spaces.

Mailenys Barrios Pérez

Universidad de Chile, Santiago de Chile, Chile. Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos, Santiago de Chile, Chile

Abstract

Different sciences have addressed the protection of biodiversity, considering biological and geographical elements, consequences of exploitation, and social, legal, and philosophical components, among others, to find alternatives that allow its conservation.

Since the 1980s, the scientific community has recognized a series of concepts of biodiversity that coincide in emphasizing that it comprises the set of animal and plant species, the environment they inhabit, and the relationships between the former and the latter, which is in line with the 1992 Convention on Biological Diversity.

From the general conceptualization of biodiversity, marine biodiversity and Antarctic marine biodiversity are considered. In the latter, the geographical element, i.e., the environment inhabited by the species that belong to it and which is subject to unique characteristics, is analyzed in a special way. The delimitation of these maritime zones is a very complex issue due to the geographical particularities of the continent, and this has repercussions on their legal protection. Therefore, the governance regime of antarctic maritime spaces is closely related to their geographical component, and the problem of their delimitation derives from three main factors: geographical conditions, claims of sovereignty over these spaces, and the convergence of two legal regimes of international law.

An adequate determination and regulation of these maritime spaces allows firstly to specify the object of legal protection; secondly, to establish the rules that can be applied; and thirdly, to identify the subjects of international law that must obey the compliance of international treaties. A fourth reason is that, having defined the object of protection, the rules, and the subjects, mechanisms can be agreed upon for the observance of the responsibilities agreed upon for the protection of Antarctic marine biodiversity.

461

Diversity and conservation of Bryophyta in Deception Island, Antarctica, based on collections of 10 years

Mel Castro Camelo, Maria Clara Gil Laydner, Allan Laid Faria, Micheline Carvalho-Silva, Paulo Saraiva Camara

Universidade de Brasilia, Brasilia, Brazil

Abstract

Antarctica is the southernmost continent on Earth and is crucial for understanding global climate changes due to its sensitivity and importance in climatic balance. Bryophyta are the most abundant terrestrial organisms in Antarctica, capable of surviving extreme conditions. They play a vital role in the ecosystem, providing habitat and food for other forms of life, including microinvertebrates and others. Deception Island is an active volcano situated in the South Shetland Island archipelago, and had recent eruptions in 1967, 1969 and 1970. However, since then, plants have recolonized the island. The existence of geothermally active sites provides a unique habitat for bryophyte communities, benefiting from the heat and humidity. Many species occurring on this island are unknown or rare and is also one of the most popular tourist sites in Antarctica. Thus, an Antarctica Specially Protected Area (ASPA 140) has been designated, including 11 distinct sub-sites, each with unique vegetation features. After 2013, only Brazilian researchers and students collected samples in Antarctica. Therefore, the present study aims to verify the diversity and conservation of bryophytes on Deception Island and assess the occurrence of species within and outside these protected areas. For this purpose, we examined the dataset of bryophyte specimens deposited in the herbaria from Brazil, collected between 2014 and 2020. At present, 57 moss species are considered to occur on Deception Island based on literature and according to three main herbaria (UB, CGMS and MBM) which 55 species belong to 40 families and 47 genera with 16 only found outside protected areas. Within the ASPA, 29 species were found, including two exclusive and 4 new records. It is essential to intensify the sampling of bryoflora on Deception Island to monitor moss communities, these collections are also helpful for conservation and potential changes in the island's management plan.

462

Analysis of the survival conditions of emperor penguins on Snow Hill and Cape Washington Islands

Cecília dos Santos Tavares^1,2, Dr. Andrea Presotto^3,1, Marcelo Romão Oliveira¹, Dr. Luciana Bassi Marinho Pires¹

¹World Environmental Conservancy, Atlanta, USA. ²Federal University of Itajuba, Itabira, Brazil. ³Salisbury University, Salisbury, USA

Abstract

This work shows the results of serial measurement of fast ice carried out on the Cape Washington and Snow Hill Islands and its influence on the emperor penguin colonies that inhabit these regions. Emperor Penguin colonies arrive on the islands during the winter to breed, and fast ice is extremely important to ensure a good survival rate for the chicks. By developing this work, we were able to measure assess the colonies’ risk of extinction. With the early breakup of the fast ice, the baby penguins are not yet ready to face the freezing waters of the sea, and, with the late breakup of the ice, the route taken by the penguins in search of access to the sea to feed and feeding their chicks increases, which can cause the chicks to die from starvation. Images from the Sentinel Hub database and images available in the Worldview tool from NASA's Earth Observing System Data and Information System (EOSDIS) were used. To analyse Snow Hill Island, data from the Marambio Station were used, and for Cape Washington Island, data from the Mario Zuchelli and Jang Bogo Stations were used. The annual number of days of ice cover on the Islands were recorded. Through image analysis, a database was created with early and late ice breakup on the Islands as well as videos to visualize the melting process. The results demonstrated that, fortunately, Cape Washington Island has demonstrated stability, due to its location further inland from the continent, thus ensuring the maintenance of this penguin species at that location. Unfortunately, the opposite has been happening in the Snow Hill Island colony, located close to the Antarctic peninsula, where the fast ice has been breaking up increasingly earlier, compromising the survival of the penguin colony located there.

463

Creating a Database of Climate Extremes and Variability in Polar Ice Cores

Brooke M. Chase^1,2, Tyler R. Jones¹, Bradley R. Markle^1,3, Valerie Morris¹, Bruce H. Vaughn¹, Rhys-Jasper Leon^1,3, James W. C. White⁴, Kevin S. Rozmiarek^1,3, Cassandra M. Brooks^1,2

¹Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA, Boulder, USA. ²Department of Environmental Studies, University of Colorado Boulder, Boulder, CO 80309, USA, Boulder, USA. ³Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80309, USA, Boulder, USA. ⁴College of Arts and Sciences, University of North Carolina, Chapel Hill, NC, USA, Chapel Hill, USA

Abstract

Extreme weather events are rare and occur above or below a statistical threshold of a meteorological variable's observed range. A changing climate can lead to shifts in the intensity and frequency of weather extremes. We lack essential information about high-frequency climate variability and extremes in the paleoclimate record. As part of the Beyond Mean Climate project, we are creating a statistical database of climate variability and extremes in multiple Greenland and Antarctic ice cores, providing both temporal and spatial viewpoints across a range of climate proxies. The database will include existing records of high-resolution water isotopes and impurities and a new record of water isotopes from GISP2 (Greenland Ice Sheet Project 2 ice core) which will be resampled starting in summer 2024 at the NSF-Ice Core Facility. The initial statistical database of climate indicators will include the mean, standard deviation, extreme values using the tail ends of probability distributions, and spectral analysis to determine the average amplitude across different frequency bands. As this project is just commencing in 2024, we will present initial results from a variety of cores including, WDC (West Antarctic Ice Sheet Divide ice core), SPC (South Pole Core), and EGRIP (East Greenland Icesheet Project ice core). Preliminary analyses of the cores show a variety of results. WDC suggests that during the Antarctic Cold Reversal (ACR: 13-14.7 ka) there are large excursions toward more extreme cold values, but little change in warm extremes. We seek to investigate what climatic process drove these winter extremes during the ACR. Results from EGRIP show evidence of warm and cold extremes rising and falling with Dansgaard-Oeschger (D-O) events, as expected. We will provide a broad range of statistical indicators to the climate modeling community to improve the accuracy of climate predictions. These findings bring new, valuable understanding to paleoclimate records.

464

PRELIMINARY ANALYSIS OF THE WEATHER CONDITIONS INFLUENCE ON THE ANOMALOUS REDUCTION AND EXPANSION OF SEA ICE IN ANTARCTIC

Cecília dos Santos Tavares^1,2, Dr. Ana Carolina Vasques Freitas^2,1, Marcelo Romão Oliveira¹, Dr. Luciana Bassi Marinho Pires¹

¹World Environmental Conservancy, Atlanta, USA. ²Federal University of Itajuba, Itabira, Brazil

Abstract

Sea ice plays a fundamental role in regulating the climate, by inhibiting heat exchange, affecting atmospheric and oceanic circulation and, although the behavior of ice shelves is variable, once they disintegrate, recovery is not possible until the ocean cools sufficiently, which is likely to occur, if ever, only after several centuries. The formation of sea ice in Antarctic is influenced by meteorological conditions, such as air temperature, sea surface temperature (SST), atmospheric pressure at mean sea level, wind speed and direction. This study shows preliminary analyses of the influence of these meteorological conditions on the anomalies in the Antarctic sea ice extent from 2000 to 2023. Trends in sea ice were assessed using the Man Kendall test and critical years of ice cover expansion and reduction were identified in order to verify the associated weather conditions. For this assessment, the Antarctic sea ice extent dataset was obtained from National Snow and Ice Data Center (NSIDC). Meteorological data was obtained from the ERA5 reanalysis, and the Meteomanzm platform was also used to collect data recorded by the four selected stations (Palmer, Dumont D’urville, Davis and Neumayer). The Meteomanzm platform is a meteorological database supplied by meteorological stations, spread across the globe, through numerical codes - SYNOP (Surface Synoptic Observations) and binary data - BUFR (Binary Universal Form for the Representation of meteorological data) from the World Meteorological Organization (World Meteorological Organization - WMO). Furthermore, the site provides access to data from global forecast models GFS (Global Forecast System) and ECMWF (European Center for Medium-Range Weather Forecasts). The findings may contribute to better understanding of the Antarctic sea ice extent on global climate change.

465

Development of a numerical scheme for regridding between ice-sheet model on polar stereographic projection and climatemodel on geographic coordinate

Fuyuki SAITO¹, Dr. Takashi Obase², Dr. Ryouta O'ishi², Dr. Ayako Abe-Ouchi²

¹Japan Agency for Marine-Earth Science and Technology,, Yokohama, Japan. ²Atmosphere and Ocean Research Institute, Univ. of Tokyo, Kashiwa, Japan

Abstract

Ice sheet evolution is often described as responses to variation of other climate systems such as atmosphere and ocean, however, it is well known that there is interaction between the systems and the changes in ice-sheet do feedback on the other systems. Therefore development of coupling models, which simulate the climate components simultaneously, is an important subject in order to compute the evolution of ice-sheet with high accuracy.
The model domain of global climate models is typically defined on geographic (longitude-latitude) grid system on a (true) sphere, while that of ice-sheet component is typically defined on regional cartesian grid on the polar stereographic projection of an ellipsoid. Exchanges of information between climate and ice-sheet models such as the surface mass balance require a function to absorb the difference of the model structures and, in particular, not to break the conservation. In addition, as already discussed by Fischer et al. (2014), the different structure of the models may cause the projection errors and geometric errors.
In this study, the module adopted in the climate model MIROC to exchange the information between the atmosphere and ocean components (Suzuki et al. 2009) is extended to work with the polar stereographic projection, which uses tiny spherical segments as a unit of the overlaping area. It is further extended by introducing the idea of Takeshima (2020) or Fischer et al. (2014), which computes overwrapping area of both models using spherical polygons.
In the present study, the peformance of the library will be presented in terms of numerical efficiency and also influence of the projection errors and geometric errors on ice-sheet simulation.

472

Fabrication of Sprayable Coatings of Polymer/Ionic Liquid/SiO₂ Nanoparticles Composite for Anti-icing Application

Dr. Aravind Patil¹, Ngoc Le Trinh², Youngho Kang², Prof. Han-Bo-Ram Lee², Dr. Hackwon Do¹, Dr. Joohan Lee¹, Dr. Changhyun Chung¹

¹Korea Polar Research Institute, Incheon, Korea, Republic of. ²Incheon National University, Incheon, Korea, Republic of

Abstract

Ice accretion on surfaces poses significant challenges across residential and industrial sectors. To address this issue, hydrophobic polymer/ ionic liquid (IL) composite coatings have been recently utilized to reduce ice adhesion and enhance freezing delay time. However, the polymer/IL-based coatings which have the potential to minimize contact area at the ice/coating interface and manipulation in freezing has not yet been studied. Herein, we have proposed a spray deposition approach for the preparation of anti-icing coating using poly(dimethylsiloxane) (PDMS)/IL/SiO₂ nanoparticles (NPs) composite. Structural analysis and density functional theory (DFT) calculations performed to support the ion-dipole interactions between PDMS and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI). Optical and FESEM analyses demonstrated that PDMS polymeric chains effectively confine EMIMTFSI within their matrix. The presence of EMIMTFSI on the surface is responsible for the formation unfrozen liquid layer at the ice/coating interface, which leads to the reduction in ice adhesion. Integration of SiO₂ NPs into PDMS/EMIMTFSI composite created a porous 3D micro-nanostructured superhydrophobic surface, which facilitates a reduction in the interfacial contact area between ice and coating. The synergism of reduced interfacial contact area and manipulation of freezing attributed to the presence of EMIMTSI at the interface, results in enhanced freezing delay time (FDT) as well as a significant reduction in ice adhesion strength (IAS). This sprayable EMIMTFSI IL-based coating indicates the feasibility of practical anti-icing coatings in extreme cold environments.

*Corresponding author’s Email: ch.chung@kopri.re.kr

Keywords: Ionic liquid, Anti-icing, Unfrozen liquid layer, Freezing delay, Textured surface, Interfacial contact area.

Acknowledgements

This work was supported by Korea Institute of Marine Science & Technology Promotion (KIMST) grant funded by the Ministry of Oceans and Fisheries (KIMST-20210629).

474

PHYLOGENOMICS OF DESCHAMPSIA (POACEAE) SPECIES FROM THE SOUTHERN CONE OF SOUTH AMERICA

Micaela Conejeros^1,2,3, Dr. Pablo Guerrero^1,2,3

Abstract

The genus Deschampsia P.Beauv, characterized as a lineage of grasses frequent in frost-prone areas. It consists of at least 50 species, 15 of which are found in South America, with the southern Andes of Chile and Argentina being an important focus of diversity of the genus. The main disagreements on the systematic delimitation of Deschampsia species are related to the high degree of morphological similarity and overlapping diagnostic characters. This study aims to infer the phylogenomic relationships among species of the genus Deschampsia from the southern cone of South America, using ancient plant tissue. Specimens were obtained from the herbarium of the University of Concepción (CONC) and the National Herbarium of Paris (P). We sequenced a total of 30 samples corresponding to 22 species. We used the genomic technique of targeted sequencing using the "Angiosperm353" probe set, which allows us to sequence hundreds of genes previously identified and highlighted for their phylogenetic informative value. We performed a Bayesian phylogenetic reconstruction to infer evolutionary relationships between species. We obtained high quality sequences of most species, one of them more than 100 years old. Our results show a well-resolved consensus tree with high a posteriori values at the nodes. The species of Deschampsia from the southern cone of South America do not constitute a monophyletic group, exhibiting a mixed pattern where species are intermixed with those from other continents. The clade with the largest number of species from the southern cone includes D. elegantula, D. setacea, D. patula, D. cordillerarum, D. danthonioides and D. pulchra; however, other species were placed in different clades. D. laxa and D. antarctica (sample from Crozet Island) were placed as sister species. Our results suggest that long-distance dispersal has been an important process in shaping the extant Deschampsia species in the southern cone of South America.

475

ASPAs as the Quintessence of Science Diplomacy? A Situational Analysis of Integrative Negotiation in ASPA 178

PhD Candidate Marco Volpe

University of Lapland, Rovaniemi, Finland

Abstract

Science Diplomacy studies how scientific-based knowledge and foreign policy interact. Antarctic Special Protected Areas (ASPAs) are established upon scientific-informed knowledge and managed by parties. Negotiated between parties and designated to conduct joint scientific research, they represent a good example to disentangle the complexity of scientific knowledge and policy-making interactions in the Antarctic system. ASPAs are mostly regarded as valuable mechanisms to foster international scientific cooperation but also represent an element of territoriality, which is often associated with national interests.

The negotiation process is a key moment of balancing interests and reaching mutual benefits, and the outcome is dependent on the party’s acceptance, rejection and interest. Distributive Negotiation maximises each of the parties' share at the expense of the other party, it includes an adversarial position focusing on dividing resources and it results in a win-lose or zero-sum negotiation. Integrative Negotiation aims to reach mutual gain by identifying shared interests and creating mutual benefits resulting in a zero-sum game.

China's dynamism in the polar regions and the increasing funding dedicated to polar science have raised scepticism about China’s long-term intentions among polar stakeholders.

Against this background, this study focuses on ASPA 178 which was recently negotiated between China, Italy and South Korea. The investigation is based on semi-structured interviews with scientists and diplomats engaged in the negotiation. Situational analysis is used to depict actors and to gain knowledge about the interdependence and power relations between groups and actors involved.

The study contributes to the ongoing theorisation of science diplomacy by exploring the conflict-lowering potential of integrative negotiation and it also sheds light on China’s Antarctic Science Diplomacy.

487

Constraining the influence of sea spray parameterization uncertainty in global climate models on aerosol size distribution, cloud formation and radiative forcing over the Southern Ocean using UKESM1-AMIP nudged simulations.

Dr Abhijith Venugopal¹, Associate Prof. Laura Revell¹, Mr Yusuf Bhatti¹, Dr Olaf Morgenstern², Dr Jonny Williams², Dr Nick Edkins²

¹University of Canterbury, Christchurch, New Zealand. ²NIWA, Wellington, New Zealand

Abstract

Sea salt aerosols (SSA) are formed when waves breaks and bubbles burst and influence

earth’s climate both directly and indirectly. The oceanic emission of sea-salt in global

climate models are parameterized as a function of either wind-speed or wind-speed and sea surface temperature. A recent study highlighted that there exists significant intermodal differences in radiative forcing in climate models when SSA emissions are doubled, in particular over the Southern Ocean. This diversity arises due to either parameterization uncertainty or the model uncertainty.

To comprehend the role of parameterization sourced uncertainty, here we implement various SSA parameterizations used in major climate models into a single model (atmosphere-only UK Earth System Model Version 1 (UKESM1)), whereby the model physics remains unchanged. Our analysis indicate that the parameterization based uncertainty can drive notable differences in sea-salt emissions and contribute significantly to radiative forcing, directly by influencing the scattering and indirectly by impacting the aerosol number size distribution and thus the formation of clouds. This effect is observed to be more pronounced over the Southern Ocean. Hence, our results indicate that reducing the uncertainty associated with parameterizations would be critical to minimize the radiative bias in the models over the Southern Ocean which would then carry major implications for Antarctic climate and ice sheet modelling.

488

Mapping sub-ice shelf bathymetry using physics-informed neural networks

Lu Li

School of Earth Sciences, The University of Western Australia, Perth, Australia

Abstract

The sub-ice shelf bathymetry, which plays a crucial role in how warm ocean melt ice shelves, remains largely unknown due to the logistical challenges of direct mapping. Thus, the broad structure of bathymetry is modelled through the inversion of airborne gravity data. Methods such as gravity shift or topography shift have been applied to major ice shelves, providing insights into bathymetric variations. However, these inversions typically rely on a presumed density contrast between the ocean and the bedrock/sediment interface.

It is important to note that gravity inversion is inherently underdetermined, as gravity anomalies can be attributed to changes in geometry, density, or a combination of both. To address this issue, I use physics-informed neural networks to simultaneously resolve both geometry and density. The covariance between bathymetry and density is utilized to constrain the spatial variation of these parameters. The proposed method offers a realistic pathway to constrain the bathymetry under ice shelves.

489

Mapping pre-glacial landscapes beneath the East Antarctic Ice Sheet

Dr Stewart Jamieson¹, Mr Edmund Lea¹, Dr Neil Ross², Dr Guy Paxman¹, Dr Michael Bentley¹, Dr Fiona Clubb¹, Dr Shuai Yan³, Dr Duncan Young³, Dr Martin Siegert⁴

¹Durham University, Durham, United Kingdom. ²Newcastle University, Newcastle, United Kingdom. ³Univeristy of Texas, Austin, USA. ⁴University of Exeter, Penryn, United Kingdom

Abstract

The East Antarctic Ice Sheet (EAIS) has persisted for at least 14 million years and has its origins ca. 34 million years ago. During periods of global climate change the EAIS margins fluctuated, resulting in periods of extensive vs. restricted ice cover resulting in differential modification of the Antarctic landscape by glacial erosion and associated processes. Areas that remain largely unmodified by the ice sheet offer a window into both pre-glacial conditions and long-term ice sheet basal conditions. Here, we use ice surface data including Radarsat and REMA to map selected buried landscapes in East Antarctica.

We interpret these landscapes as being relict pre-glacial topographies that have been modified by both rivers and then local-scale glaciers. At Highland A, the relic landscape hosts a network of valleys initially formed by rivers prior to ice sheet build-up, but later modified by local glaciation. In the Gamburtsev region our mapping shows detail of mountain ridges and valleys on wavelengths significantly smaller than the spacing of existing radar flightlines, and does so beyond the confines of the AGAP RES survey. As a result we can visualise the layout of the Gamburtsev Subglacial Mountains and their ‘foothills’ in unprecedented detail.

Preservation of the relic surfaces is indicative of an absence of significant warm-based ice flow throughout their history, suggesting rapid transitions between restricted and expanded ice sheets, and a long-term stable thermal regime. We suggest that it would be beneficial to conduct more widespread explorations of the detailed subglacial geomorphology of the EAIS in order to gain insight into past ice behaviour and landscape evolution. Moreover, such landscapes tell us about past ice sheet basal conditions and potentially fluctuating behaviour and we therefore raise the possibility that these preserved landscapes could be used as ‘thermal’ constraints for ice sheet models.

491

Towards linking Subglacial Geological Conditions with Ice Sheet Model Parameterization

Lu Li¹, Mareen Loesing^1,2, Alan Aitken^1,2

¹School of Earth Sciences, The University of Western Australia, Perth, Australia. ²The Australian Centre for Excellence in Antarctic Science, The University of Western Australia, Perth, Australia

Abstract

Understanding future changes of the Antarctic ice sheet requires knowledge of subglacial boundary conditions, including the spatial variation of bed rheology, basal slippiness, and ice viscosity to adequately represent the ice dynamics.

In the current modelling framework, subglacial boundary conditions are initialized using an inverse method to infer basal boundary conditions that match ice thickness and velocity derived from satellite observations. The inversion result is known to be underdetermined, leading to a trade-off between different parameters. Meanwhile, subglacial geological conditions significantly influence ice sheet dynamics, yet there is no direct method to incorporate this geological knowledge into the ice sheet flow model.

To address this issue, we propose a new inverse approach that derives basal boundary conditions with respect to geological information, constrained by multiple geophysical data sources. Utilizing information theory, this method couples basal slipperiness with geological information during the inversion process. Our aim is to establish a statistical relationship between geological content and basal boundary conditions and quantify the geological impact on ice sheet dynamics.

494

Internal Family Dynamics in Antarctic Expeditions

Ms. Nanako KATO

Osaka　Shoin Women's University, Osaka, Japan

Abstract

Japan's Antarctic expeditions covers a summer period in Antarctica and an overwintering expedition in which a fixed number of members spend approximately one year in Antarctica. Although they can communicate with their families through email and other means, members often feel isolated from their families. Many also reported that as a national project, the Antarctic observation mission is an opportunity for self-realization as a life challenge and childhood dream. Party members of the Antarctic wintering group reported in their post-return interviews that such conflicts with their families were also expressed. Readjustment to their families upon their return was also a major issue. Previous studies focused on the thoughts and feelings expressed by members, not analyzing the dynamics of those thoughts and feelings, including those of their families, who experienced the absence of members.

In this study, we examined the dynamics of the families of the Antarctic expedition members using a qualitative analysis of correspondence (emails) in two published accounts of their experiences. The multiple pathway and isochronous model (TEM) enables us to examine the commonality and individuality of the cases through the convergence and development of various pathways toward the isochronous point, using a junction or an essential passage point as a landmark.

In this study, we present details of the adaptation and readaptation processes of corps members’ families. Unlike other business trips, the uniqueness of Antarctic expeditions was extracted, as it is an experience of intense separation and a reflection on one's own existence, including one's family.

495

Late-Neoproterozoic mafic alkaline dike swarm of Bunger Oasis, East Antarctic, petrogenetic model and implications for East Gondwana post-orogenic evolution

Mr. Nikita Borovkov¹, Mr. Vladimir Vodovozov²

¹All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean" (FSBI "VNIIOKEANGEOLOGIA"), Saint-Petersburg, Russian Federation. ²Moscow State University, Faculty of Geology, Moscow, Russian Federation

Abstract

Sufficient volume of geological, particularly tectonically concerned, studies determined the eastern limit of Pan-African activity at the middle axe of Denman Glacier: eastwards from this line, there are no metamorphic events or syn- or post-orogenic granitoid intrusions of ~500 Ma age. However, Bunger Oasis area, located eastwards from Denman Glacier, are characterized by mafic alkaline dike swarm of ~500 Ma age. Petrogenetic models for the geodynamic setting specification at the emplacement time are the aim of the presented study. The dike swarm is divided in two main groups: (1) Basanites, tephrites and picrobasalts ( intergranular to granular or poicilitic texture, contain clinopyroxene, albitic plagioclase, biotite or phlogopite, olivine, kaersutite or ferroan pargasite; Ol-normative, Ne-normative, alkaline magnesian rocks; crystallization time: 395±10 Ma, Sm-Nd isochron, published previously), (2) alkali basalts and trachybasalts (porphyritic, olivine and diopside or labradorite-andesine plagioclase, fine-grained matrix of biotite, alkali feldspar, minor clinopyroxene and amphibole; only Ol-normative or Di-normative; crystallization time: 525±10 Ma, zircon U-Pb, published previously). Swarms trachyandesitic, phonotephritic and doleritic dike (tholeiitic) swarms postdate syn- and post-orogenic magmatism related to Mesoproterozoic orogeny and, possibly, relate to early stages of Rodinia breaking up, i. e. represent transition from post-orogenic uplift to within plate. According to geochemical properties basanites represent near-primary melt while tephrites (lower LILE content) represent higher degree melts due to fractional crystallization. Alkali basalts are characterized by high LREE and incompatible elements (K, Ba, Rb, Sr, Th, U) contains corresponding to OIB. Radiogenic and stable isotope data indicate derived from an enriched mantle source with a major Nb-rich OIB-type component what can be achieved during the delamination processes after Pan-African orogeny cessation (roll-back of subducted slab and detachment, post-collisional gravitational collapse of the overthickened lithosphere leads to trace element and isotopic fingerprints reflecting enrichment of their source regions by subduction-related fluids).

496

Radar site survey for subglacial drilling to test hypotheses of West Antarctic ice sheet collapse

Professor Neil Ross¹, Professor Mike Bentley²

¹Newcastle University, Newcastle, United Kingdom. ²Durham University, Durham, United Kingdom

Abstract

The potential for West Antarctic Ice Sheet (WAIS) collapse is a major societal challenge. One way to explore this potential is to look at evidence of past intervals of collapse preserved in the geological record. This is particularly challenging because most of the evidence is likely to be located beneath the present-day ice sheet. The European Research Council-funded INCISED project is using new lightweight drills to access and sample rock from the bed of the WAIS and to undertake cosmogenic analysis on these samples in order to test hypotheses of WAIS collapse.

The drilling requires careful site selection to meet key drill site criteria and one of these is to understand the local ice thickness, and the pattern of bedrock topography beneath drill transects. Here we report new sled-based high-resolution radar surveys for two drill transect sites in West Antarctica that have allowed us to identify drill locations for season 24-25. For the two sites, located adjacent to upper Evans ice stream and to upper Rutford ice stream, we report the grids of survey lines and discuss bedrock topography, links to above-ice topography, and uncertainties in bedrock depth from crossover analysis. We also report near-surface patterns in layering that may record recent changes to winds and/or ice flow.

498

Can GPS observations be used to map mantle properties under West Antarctica?

Dr Grace Nield¹, Professor Mike Bentley¹, Dr Achraf Koulali², Professor Peter Clarke², Professor Michiel van den Broeke³, Professor Terry Wilson⁴, Professor Matt King⁵, Professor Pippa Whitehouse¹

¹Durham University, Durham, United Kingdom. ²Newcastle University, Newcastle, United Kingdom. ³University of Utrecht, Utrecht, Netherlands. ⁴Ohio State University, Columbus, USA. ⁵University of Tasmania, Hobart, Australia

Abstract

Surface mass balance (SMB) variability is known to trigger an elastic response of the solid Earth. In Antarctica, it is important to correct GPS observations for this signal before they can be reliably used to constrain models of geophysical processes such as glacial isostatic adjustment (GIA). However, much of West Antarctica is underlain by weak upper mantle, meaning that the Earth may also be deforming viscously in response to changes in surface load on short (decadal) timescales. In this study we investigate whether SMB variability in the Antarctic Peninsula is triggering a viscoelastic response of the solid Earth, a signal that has not previously been considered. We estimate the magnitude and spatial pattern of short-term anomalies from the Regional Atmospheric Climate Model (RACMO2) and use this as input to a finite element model. The model predicts vertical viscoelastic deformation which can be compared with time series of GPS-observed displacement. At most sites, we find a better fit between model predictions and GPS time series when a viscous signal is included, rather than when it is assumed the response is purely elastic. Moreover, the modelling is used to infer which Earth properties produce the best fit to the GPS time series, thus providing further constraints on upper mantle viscosity in this dynamic region of Antarctica. The results have implications for ice sheet models of West Antarctica.

504

Suppressed basal melting in the eastern Thwaites Glacier grounding zone

Peter Davis¹, Keith Nicholls¹, David Holland^2,3, Britney Schmidt⁴, Peter Washam⁴, Kiya Riverman^5,6, Robert Arthern¹, Irena Vaňková⁷, Clare Eayrs⁸, James Smith¹, Paul Anker¹, Andrew Mullen⁴, Daniel Dichek⁴, Justin Lawrence⁴, Matthew Meister⁴, Elisabeth Clyne^9,10, Aurora Basinski-Ferris², Eric Rignot^11,12, Bastien Queste¹³, Lars Boehme¹⁴, Karen Heywood¹⁵, Sridhar Anandakrishnan⁹, Keith Makinson¹

¹British Antarctic Survey, Cambridge, United Kingdom. ²New York University, New York, USA. ³New York University Abu Dhabi, Abu Dhabi, UAE. ⁴Cornell University, Ithaca, USA. ⁵Oregon State University, Corvallis, USA. ⁶University of Portland, Portland, USA. ⁷Los Alamos National Laboratory, Los Alamos, USA. ⁸Korea Polar Research Institute, Incheon, Korea, Republic of. ⁹Pennsylvania State University, State College, USA. ¹⁰Lewis & Clark College, Portland, USA. ¹¹University of California, Irvine, Irvine, USA. ¹²Jet Propulsion Laboratory, Pasadena, USA. ¹³University of Gothenburg, Gothenburg, Sweden. ¹⁴University of St Andrews, St Andrews, United Kingdom. ¹⁵University of East Anglia, Norwich, United Kingdom

Abstract

Thwaites Glacier is one of the fastest-changing ice–ocean systems in Antarctica. Much of the ice sheet within the catchment of Thwaites Glacier is grounded below sea level on bedrock that deepens inland, making it susceptible to rapid and irreversible ice loss that could raise the global sea level by more than half a metre. The rate and extent of ice loss, and whether it proceeds irreversibly, are set by the ocean conditions and basal melting within the grounding-zone region where Thwaites Glacier first goes afloat, both of which are largely unknown. Using observations from a hot-water drilled access hole, I'll show that the grounding zone of Thwaites Eastern Ice Shelf (TEIS) is characterized by a warm and highly stable water column with temperatures substantially higher than the in situ freezing point. Despite these warm conditions, low current speeds and strong density stratification in the ice–ocean boundary layer actively restrict the vertical mixing of heat towards the ice base, resulting in strongly suppressed basal melting. The results demonstrate that the canonical model of ice-shelf basal melting used to generate sea-level projections cannot reproduce observed melt rates beneath this critically important glacier, and that rapid and possibly unstable grounding-line retreat may be associated with relatively modest basal melt rates.

508

Preliminary study on Paleoecological conditions during the Late Pleistocene, results obtained from deposits discovered on nunatak near the Søstrene islands group, Prydz Bay, East Antarctica.

Ilnur Abdrakhmanov¹, Zinaida Pushina¹, Dr. science Boris Sirenko², Nikita Borovkov¹, Vanda Sergeeva¹

¹All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean" (FSBI "VNIIOKEANGEOLOGIA"), Saint-Petersburg, Russian Federation. ²Zoological Institute, Russian Academy of Sciences, Saint-Petersburg, Russian Federation

Abstract

During the past 68^th Russian Antarctic Expedition (season 2022/23) on Princeess Elizabeth Land several nunataks outcropping in Prydz Bay area were attended. Particularly, on the nameless nunatak located in 5 km eastwards from Søstrene islands group, a deposit of marine origin was discovered. The deposit’s location represents alluvial bank of gray-green color with sandy-clayey substrate mixed with moraine deposits comprising carbonate mollusk shells, sponge spicules and diatoms. Previous studies reported the presence of such marine sequences within bottom sediments of Prydz Bay but not on shore outcrops. We share in SCAR2024 conference our preliminary results on discovered sediments. The diatom assemblage identified in this study have similar components to those found in Prydz Bay surface and bottom. Late Pleistocene sediments. Diatom flora reflects the environment in neritic conditions of marine basin with relatively cold water and ice cover. Ice-related species predominate in diatom assemblage (species of genus Fragilariopsis) and consist 43,9% of total composition. Neritic species like Thalassiosira margaritae are the most important species of antarctic open-water neritic diatoms (34,2%). The relatively high abundance of open-ocean species (especially Fragilariopsis kerguelensis) – 21,1% was established in the diatom assemblage. This fact is the evidence of the oceanic warmer water penetration. Numerous sponge spicules were also discovered; some specimens can be seen without even using a magnifying glass. They cover the deposits surface like a felt. Obtained information enables us to expand marine near-shore (relatively warm) conditions towards the Prydz Bay shore area and constrain Late Pleistocene paleoecology reconstructions for East Antarctic regions.

509

Fungal diversity present in snow sampled in summer in the South Shetland Islands, Maritime Antarctica, assessed using metabarcoding

Dr Graciéle de Menezes¹, Professor Fabyano Lopes², Graduante Karita Santos², Professor Micheline Carvalho³, Dr. Peter Convey⁴, Professor Paulo Camara³, Professor LUIZ ROSA¹

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²Federal University of Tocantins, Palmas, Brazil. ³University of Brasília, Brasília, Brazil. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

We assessed the fungal diversity present in snow sampled during summer in the South Shetland Islands, Maritime Antarctica using a metabarcoding approach. A total of 586,693 fungal DNA reads were obtained and assigned to 203 amplicon sequence variants (ASVs). The dominant phylum was Ascomycota, followed by Basidomycota, Mortierellomycota, Chytridiomycota and Mucoromycota. Penicillium sp., Pseudogymnoascus pannorum, Coniochaeta sp., Aspergillus sp., Antarctomyces sp., Phenoliferia sp., Cryolevonia sp., Camptobasidiaceae sp., Rhodotorula mucilaginosa and Bannozyma yamatoana were assessed as abundant taxa. The snow fungal diversity indices were high but varied across the different locations sampled. Of the fungal ASVs detected, only 28 were present all sampling locations. The 116 fungal genera detected in the snow were dominated by saprotrophic taxa, followed by symbiotrophic and pathotrophic. Our data indicate that, despite the low temperature and oligotrophic conditions, snow can host a richer mycobiome than previously reported through traditional culturing studies. The snow mycobiome includes a complex diversity dominated by cosmopolitan, cold-adapted, psychrophilic and endemic taxa. While saprophytes dominate this community, a range of other functional groups are present.

510

Diversity and bioprospecting of enzymes and biosurfactants of industrial interest produced by culturable fungi present in sediments of climate change impacted Lake Boeckella, Hope Bay, Northeast of the Antarctic Peninsula

Ms Elisa Teixeira¹, Ms Láuren de Souza¹, Professor Rosemery Vieira², Dr Juan Lirio³, Dr Silvia Coria³, Dr Peter Convey⁴, Professor Carlos Rosa¹, Professor LUIZ ROSA¹

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²Federal Fluminense University, NIteroi, Brazil. ³Instituto Antártico Argentino, Buenos Aires, Argentina. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

This work aimed to characterize cultivable fungi present in sediments from Lake Boeckella, located in Hope Bay, northeast of the Antarctic Peninsula, and to evaluate them for the production of enzymes and biosurfactants of industrial interest. A total of 116 fungal isolates were obtained, comprising 86 filamentous fungi and 30 yeasts. These were identified through morphophysiological characteristics and molecular biology techniques as belonging to 16 genera within the phyla Ascomycota, Basidiomycota, and Mortierellomycota, listed in order of abundance. The most abundant genera of filamentous fungi included Pseudogymnoascus, Pseudeurotium, and Antarctomyces; for yeasts, the genera Candida and Naganishia were predominant. Overall, the lake exhibited high diversity and richness of fungi with moderate dominance. The enzymes esterase, cellulase, and protease were the most abundantly produced by these fungi. Of the filamentous fungi, only those isolated from Ramgea cf. ozimecii had an enzymatic index (EI) greater than 2. The yeast taxa Holtermanniella wattica, Leucosporidium creatinivorum, Leucosporidium sp., Mrakia blollopis, Naganishia sp., and Phenoliferia sp. presented an Emulsification Index (IE) greater than 2 for more than one enzyme. The isolate Naganishia sp. UFMGCB 19775 exhibited the highest IE. In terms of biosurfactant production capability, 14 isolates of filamentous fungi demonstrated an Emulsification Index (IE24%), which included Antarctomyces psychrotrophicus, Cosmospora sp., Pseudogymnoascus sp., R. cf. ozimecii, and Thelebolus sp. Three isolates of A. psychrotrophicus showed an E24% greater than 80%, surpassing the performance of the synthetic surfactant (SDS). Yeasts such as Candida davisiana and Cystobasidium sp. 2 exhibited E24% values greater than 50%. This study showed that Lake Boeckella, which is in the process of drying out and future extinction due to the impact of climate change on the Antarctic Peninsula, hosts a community of cultivable fungi that produce important biomolecules useful in biotechnological processes.

512

Diversity of fungi present associated with Antarctic Oligocene rock core samples explored using DNA metabarcoding

Ms Natana Rabelo¹, Professor Marcelo Carvalho², Professor Sandro Scheffler², Professor Gustavo Santiago², Professor Paula Sucerquia³, Professor Fabio Oliveira¹, Dr Larissa Campos¹, Professor Fabyano Lopes⁴, Ms Karita Santos⁴, Professor Micheline Carvalho⁵, Dr Peter Convey⁶, Professor Paulo Camara⁵, Professor Vívian Gonçalves¹, Professor LUIZ ROSA¹

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ³Federal University of Pernambuco, Recife, Brazil. ⁴Federal University of Tocantins, Palmas, Brazil. ⁵University of Brasília, Brasília, Brazil. ⁶British Antarctic Survey, Cambridge, United Kingdom

Abstract

In this study, we evaluated the fungal diversity present associated with cores of Oligocene rocks using a DNA metabarcoding approach. We detected 940,969 DNA reads grouped into 198 amplicon sequence variants (ASVs) representing the phyla Ascomycota, Basidomycota, Mortierellomycota, Chytridiomycota, Mucoromycota, Rozellomycota, Blastocladiomycota, Monoblepharomycota, Zoopagomycota, Aphelidiomycota (Fungi) and the fungal-like Oomycota (Stramenopila), in rank abundance order. Pseudogymnoascus pannorum, Penicillium sp., Aspergillus sp., Cladosporium sp., Aspergillaceae sp. and Diaporthaceae sp. were assessed to be dominant taxa, with 22 fungal ASVs displaying intermediate abundance and 170 being minor components of the assigned fungal diversity. The data obtained displayed high diversity indices, while rarefaction analysis suggested that further diversity remains to be detected. However, the diversity indices varied between the cores analysed. The use of metabarcoding identified a complex mycobiome including taxa with different ecological roles, comparable with the diversity reported in recent studies of a range of Antarctic habitats. Further research is necessary to develop strategies to isolate these fungi into culture and evaluate their potential utility in evolutionary, physiological and biogeochemical research and for biotechnological applications.

513

Bioprospecting for herbicide enzymes and metabolites produced by fungi present in the sediments of Lake James Ross Island, Antarctica

Graduate Laura Martins¹, Dr Juan Lirio², Dr Silvia Coria², Professor LUIZ ROSA¹, Professor Vívian Gonçalves¹

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²Argentine Antarctic Institute, Buenos Aires, Argentina

Abstract

The present study aimed to evaluate the production of enzymes from the fungal community in sediments from lakes Cecilia and Lilia on James Ross Island, in the Antarctic Peninsula. To assess the enzymatic production of this fungal community, 138 fungi were reactivated on malt extract agar at 15°C for 7 days. The fungi were prospected to detect the enzymes agarase, amylase, carrageenase, cellulase, esterase, inulinase, invertase, lipase, pectinase, and protease. Enzymatic activity was measured according to the relationship between the diameter of the degradation halo and the diameter of the colony, termed Enzymatic Index (EI). For an isolate to be considered a good enzyme producer, the EI must be greater than 2. At the end of the experiments, 45.6% (57) of the tested fungi showed activity for at least one enzyme, while 15.2% (19) were considered good producers of the following enzymes: amylase (3), carrageenan (2), cellulase (3), esterase (9), inulinase (3), pectinase (2), and protease (3). To evaluate lipase production, the isolates were inoculated in a specific medium and observed under ultraviolet light; the results were indicated by luminescence. Thirty lipase-producing isolates were identified. The production of these enzymes by fungi present in extreme environments underscores the vital role these microorganisms play in the mineralization of organic matter and biogeochemical cycles. Identifying enzyme-producing fungi has become increasingly relevant, particularly for extremophile fungi, because of their ability to produce compounds active under stressful conditions. These results underscore the significance of fungal communities in Antarctic lakes as potential producers of industrially relevant enzymes.

517

Diversity and bioprospecting of fungi associated with macroalgae from Subantarctic regions and the Southern Chilean and Antarctic Channels

Ms Matheus Souto¹, Dr Camila de Carvalho¹, Professor Franciane Pellizari², Professor Andrés Mansilla³, Dr Tânia Alves⁴, Dr Carlos Zani⁴, Professor LUIZ ROSA¹

¹Federal University of Minas Gerais, Belo Horizonte, Brazil. ²State University of Paraná, Paranaguá, Brazil. ³Universidad de Magallanes, Punta Arenas, Chile. ⁴René Rachou Institute, Belo Horizonte, Brazil

Abstract

The objective of this work was to isolate and characterize the community of fungi associated with macroalgae present in southern Chilean channels and Antarctic regions, as well as to evaluate the potential of these fungi in terms of producing bioactive secondary metabolites. A total of 241 filamentous fungi were obtained. The identified taxa belong to the genera Antarctomyces, Pseudogymnoascus, Microdochium, Trichoderma, Cladosporium, Linnemannia, Entomortierella, Neoascochyta, Penicillium, and Cadophora. The diversity of algal and fungal communities in Antarctica demonstrated low diversity and richness, with a relative dominance rate. This fact contrasts with the fungal community of the southern Chilean channels, which exhibited high diversity and richness, with low dominance for calculated ecological indices. The 177 fungal extracts were evaluated for herbicidal, trypanocidal, and leishmanicidal activities. A total of 49 extracts showed herbicidal activity, with four capable of inhibiting 100% of the germination of A. schoenoprasum. Nineteen extracts exhibited activity against Trypanosoma cruzi trypomastigotes and amastigotes, with nine demonstrating high activity. The results suggest the presence of a fungal community adapted to the extreme conditions of the Antarctic environment and Southern Chilean channels. This study is one of the first to explore, identify, and evaluate the fungal community associated with macroalgae in the Southern Chilean channel region. Macroalgae from the Antarctic environment and Southern Chilean channels have been shown to represent a potential substrate for the isolation of associated fungi. The results of this work demonstrated that Antarctic macroalgae and southern Chilean channels may represent a reservoir of algal fungi producing bioactive metabolites, as evidenced by the detection of herbicidal and trypanocidal activities. This reinforces the need for further studies in the taxonomy and bioprospecting of macroalgae present in extreme ecosystems.

518

Phytoremediation in Antarctica: unveiling Deschampsia antarctica´s tolerance to hydrocarbons

Lic. Catalina Basile Dazzi^1,2, Dr. Francisco Massot^1,2,3, Dra. Laura Recalde⁴, Biol. María Piotto^5,6, Dr. Walter Mac Cormack^1,3, Dr. Lucas Ruberto^1,2,3

¹Instituto Antártico Argentino (IAA), Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ³Instituto de Nanobiotecnología (UBA-CONICET), Buenos Aires, Argentina. ⁴Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina. ⁵Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ⁶Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba, Argentina

Abstract

To date, diesel stands as the primary energy source in the Antarctic continent, providing reliability but also carrying the risk of mismanagement and spills. This study highlights phytoremediation as a frequently utilized and effective technology for restoring petroleum hydrocarbon-contaminated soils, even in extremely cold environments. Screening the capacity of native plant species to grow on these soils is a key factor for developing a successful phytoremediation process. Here, we investigate the potential of Deschampsia antarctica Desv. (Poaceae) as a phytoremediation tool, using specimens grown in the 25 de Mayo Island. We carried out a dose-response assay to elucidate the tolerance of D. antarctica to increasing concentrations of Antarctic diesel under in vitro conditions. In vitro setups offer information on the plant's solo capacity to develop in a maximum xenobiotic availability environment. The experimental design included diesel concentrations ranging from 0 to 10000 ppm. After 75 days of the experiment, fresh and dried samples were analyzed for above and underground biomass production, root development, chlorophyll content, and antioxidant enzymes activity. Generalized Linear Models were fitted to estimate the inhibition dose 50 (ID50) for biometric variables and to characterize the chlorophyll content and antioxidant enzyme activity throughout increasing diesel concentrations. The estimated ID50 was 9547 ppm for aboveground biomass production, and 7030 ppm and 3758 ppm, for underground biomass production and root development, respectively. The models showed a decrease in chlorophyll content of 5.535 mg gFW^-1 when the diesel concentration increased from 0 to 10000 ppm. The guaiacol peroxidase activity increased 3.19 mmol g protein^-1 min^-1 in aboveground tissues after the same diesel increment but decreased 2.65 mmol g protein^-1 min^-1 in underground tissues. This study represents the initial investigation into the response of a native Antarctic plant to diesel contamination, laying the groundwork for the development of efficient phytoremediation technologies designed for cold climates.

519

Detection of enzymes, biosurfactants, and lipids of industrial interest produced by Antarctic fungi

Ms Elisa Teixeira, Ms Láuren de Souza, Professor LUIZ ROSA

Federal University of Minas Gerais, Belo Horizonte, Brazil

Abstract

Microorganisms capable of surviving extreme conditions are called extremophiles and have attracted significant biotechnological interest in recent years, mainly due to their production of enzymes, biosurfactants, and lipids. Considering the diverse biotechnological applications of microorganisms found in Antarctica, this work aimed to isolate fungi from different lignocellulosic substrates (wood, rope, and soil from the whaling station) located in Whalers Bay, Deception Island, maritime Antarctica, and test their capacity to produce industrially interesting enzymes, biosurfactants, and lipids. From the evaluated substrates, 58 fungal isolates were obtained, comprising 24 yeasts and 34 filamentous fungi. Of these, 47 were identified and classified into 17 genera. The phyla Ascomycota and Basidiomycota were represented by nine and eight genera, respectively. The most frequent genus was Coniochaeta (10 isolates = 21.3%), followed by Cadophora, Pseudogymnoascus, and Mrakia (6 isolates each = 12.8%) and Leucosporidium (4 isolates = 8.5%). Tests related to the production of the enzymes amylase, cellulase, inulinase, and pectinase were carried out with all isolates. Amylase was the most commonly detected enzyme, followed by inulinase, cellulase, and pectinase. No fungi were able to produce biosurfactants. From the selective isolation using 8% polyacrylamide (PA) ethanol, two isolates of the yeast Solicoccozyma terricola were obtained, capable of producing intracellular lipids at low temperatures. The data obtained in this work contribute to the understanding of fungal diversity in Whalers Bay and the biotechnological potential of these microorganisms, as they are capable of producing enzymes and lipids at low temperatures.

522

Molecular composition of soil organic matter: a case study in soils of the Byers Peninsula, Maritime Antarctica

Dr Jônatas Silva¹, Graduate student Anifo Ibraimo¹, Dr. Deborah Dick², Dr. José Souza¹, Dr. Emanuelle Soares¹, Dr. Carlos Schafer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Abstract

The knowledge about whole soil organic matter (SOM) in polar regions, specifically on the Byers Peninsula in Maritime Antarctica, remains limited. This study aimed to investigate the molecular composition of whole SOM in selected soils. Eight soil profiles were sampled and analyzed being P2, P6, P11, and P12 representative of the low platforms; P3, P4, and P10 representative of the high platforms, and P7 representative of the raised beaches. The SOM molecular composition was investigated by 13C NMR-CP/MAS spectroscopy in HF-treated samples. The most abundant group determined by 13C NMR was the O-alkyl C group (13.8 to 58.6 %) followed by alkyl C groups (23.6 to 49.8%). The aryl C (110-160 ppm) and carbonyl C (160-190 ppm) groups contributed in smaller proportions to the composition of the SOM, between 6.5 and 40.8% and 6.7 and 22.1%, respectively. The exceptions were the P2 and P4 soils, whose spectra showed a comparatively greater contribution of aryl C (18 to 40.8%) and lower O-alkyl (13.8 to 35.6%), characterizing this SOM as of greater recalcitrance. The greater SOM aromaticity and complexity from P2 and P4 profiles were corroborated by its comparatively higher thermostability as determined by TGA analysis. The SOM of other profiles, P3, P6, P7, P10, P11 and P12, showed a 13C-NMR spectrum dominated by O-alkyl-C. This pattern characterizes the SOM as being comparatively more labile than that in P2 and P4. The soils of the Byers Peninsula showed a diverse and varied molecular nature of SOM, with contrasting patterns between a more labile and recalcitrant composition. Despite the relatively high SOM lability in most of the studied profiles, the high aliphaticity also reflects a relevant hydrophobicity of the organic matter in this environment. Our pioneering and unprecedented results provide some insights into the whole SOM formation in Maritime Antarctica.

523

Chinstrap penguin blood biochemistry on arrival at nesting site and the comparison with the reproductive and moult stage

PhD CARLA DI FONZO, LICENCIADA CAMILA CILVETI, PhD STUDENT BRUNO FUSARO, PhD MARTÍN ANSALDO

INSTITUTO ANTARTICO ARGENTINO, BUENOS AIRES, Argentina

Abstract

The Chinstrap Penguin (Pygoscelis antarctica) is a common seabird in the Antarctic ecosystem. The arrival of adults to the coast to breed begins in late September or early October, the breeding season lasts until February and moulting occurs at the end of this period. The Antarctic Peninsula is experiencing significant environmental variability and loss of sea ice cover as a result of rapid climate warming. These conditions expose penguins to environmental extremes, variations in food availability and thermal stress, and forced them to make trade-offs between physical maintenance and energy expenditure at different stages of their life cycle. It is essential that the penguins start their breeding season in optimal conditions in order to reach the end of the season without complications. In order to know their physiological state at each stage, blood biochemistry (levels of total proteins, uric acid, calcium, inorganic phosphorus, and glucose), oxidative damage (lipid peroxidation, and protein oxidation) and body mass were measured in adults at three stages: pre-breeding, breeding and moulting. It was found that the values measured were within the expected range for this species. As expected, penguin weights were the highest in the pre-breeding stage. This period was the most variable. In turn, uric acid and lipid peroxidation levels were highly variable during this period due to high lipemia.

526

Blood biochemistry and oxidative status of Adélie and Gentoo penguins in the pre-breeding period on arrival at different nesting sites

PhD CARLA DI FONZO, Phd STUDENT BRUNO FUSARO, PhD MARTÍN ANSALDO

INSTITUTO ANTARTICO ARGENTINO, BUENOS AIRES, Argentina

Abstract

Adélie (Pygoscelis adeliae) and Gentoo (Pygoscelis papua) penguins are the most abundant seabirds in the Antarctic ecosystem. Although they share the same genus, they have different life histories and habitat preferences. As a result of rapid climate warming, the Antarctic Peninsula is experiencing significant environmental variability and loss of sea ice cover. These conditions expose penguins to environmental extremes, variations in food availability and thermal stress, forcing them to switch between physical maintenance and energy expenditure at different stages of their life cycle. Penguins are also a key species in the Antarctic food web, with a marked trend of population decline. It is therefore important to know the physiological status during the pre-breeding stages, as this could influence reproductive success. For this reason, blood samples were taken and, plasma and erythrocytes were separated. The levels of total protein, uric acid, calcium, inorganic phosphorus, glucose, and oxidative damage (lipid and protein oxidation) were measured in the plasma fraction. Besides, levels of reduced glutathione (GSH) and the antioxidant enzyme activities of catalase and glutation-S-transferase (GST) and oxidative damage were measured in the erythrocyte fraction. The study was conducted in three penguin colonies. The locations of the sampled colonies are Cabo Funes/Stranger Point 25 de Mayo/King George Island; Esperanza/Hope Bay, Trinity Peninsula, Antarctic Peninsula and Marambio Island. The biochemical values observed are within the expected range. Adélie has no differences between sites, but Gentoo has higher glucose and uric acid levels and lower calcium levels in Cabo Funes as well as higher weight. The Adélie antioxidant enzyme activity and GSH levels were lower in Cabo Funes than in Esperanza Hope. On the other hand, Gentoo showed similar levels of oxidative damage between nesting sites. In terms of antioxidant defences, Esperanza Hope penguins had higher GSH levels and higher GST activity.

529

MONITORING THE LICHEN COMMUNITY ON THE COCKBURN ISLAND PLATEAU

Dr Laura Patricia Dopchiz, Student grade Sofía Ozon, Dr Alfredo Costa, Dr Martín Ansaldo

Instituto Antártico Argentino, Gral. San Martín. Pcia. Buenos Aires., Argentina

Abstract

Climate change generates effects on the terrestrial ecosystems of the Antarctic Peninsula that need to be studied. The Cockburn Island Plateau (James Ross Archipelago) has an inhospitable appearance. Even so, it has a cover of lichens and mosses.

The information on the composition of the lichen community of the plateau is outdated since it dates from Lewis Smith's expedition (1989).

The objective of the present work is to evaluate whether the lichen community of the island plateau has changed since the last sampling in 1989 as a result of climate change. For this purpose, samples were taken during the 2022 and 2023 summer Antarctic campaigns. Each species sampled was georeferenced. Thallus were measured and cross-sections were made. Species belonging to 8 genera were identified. The data obtained serve as a comparative starting point for community monitoring.

Contrary to what was observed in maritime Antarctica, where climate change showed unfavorable effects on lichen communities, the present results show the growth of the lichen community evidenced by the increase in the number of species, mainly of the genera Caloplaca, Leptogium and Usnea. This alteration could be associated to the negative trend shown by summer temperature (DJF) in Marambio Base during the period 1991-2020: -0.31°C/decade. Given that not all lichens are vulnerable to climatic pressures, species with restricted distribution such as Usnea antarctica, could be used as indicators of the effect to climate change given their vulnerability (Bokhorst et al 2016). Since Cockburn is a small island (2.7 km in size), long-term monitoring of plant communities is important as it will allow us to project their reaction and resilience to climate change on the islands that make up the archipelago.

530

Influence of landforms and parent material on soil formation and its depth in the Ulu Peninsula, James Ross Island, Antarctica

Dr. Fernando Villela¹, Msc. Heitor Palma², Professor Marcio Francelino², Professor Carlos Schaefer²

¹University of Sao Paulo, Sao Paulo, Brazil. ²Federal University of Viçosa, Viçosa, Brazil

Abstract

The Ulu Peninsula exhibits a wide variety of geological and geomorphological features, with higher regions typically being volcanic and lower portions sedimentary. This study aimed to establish how landforms and parent material influence the soil formation and its depth. Eight soil profiles were described, with four of them according to sedimentary materials and the other from volcanic rocks. Maximum depth was measured, profile altitudes were acquired via GPS and field survey was based on an interpolation of a regional topographic map. Descriptive analysis of the region and a linear regression between depth and altitude were conducted for result interpretation. The regression shows a decreasing curve, with an R² of 0.9316, indicating that as altitude decreases, the tendency is to find deeper soils. Descriptive data show that the shallowest soils in the region are found in higher regions, where volcanic rocks are present, while the deepest soils are found where sedimentary rocks prevail. One key point for analysis is the geological ages of the materials; while volcanic rocks date back to the Upper Miocene and Pliocene, sedimentary rocks date back to the Cretaceous, allowing more time for sediment accumulation and consequently pedogenesis and horizon development. Additionally, chemical weathering in Antarctica is less active than physical weathering; thus, soils with in-situ formation tend to have less thickness compared to older depositional areas formed by sediment accumulation mainly from erosion, transportation and deposition, adding also disintegration due to physical weathering. It is concluded that soils in higher portions of the landscape tend to have lesser depth due to higher rates of physical weathering over chemical weathering, as well as more recent ages of volcanic lithology.

532

The differences in level of fine water-soluble solid fraction present in dehydrated Antarctic lichens as compared to that in Atacama Desert species as seen using ¹H-NMR

Professor Hubert Haranczyk¹, M.Sc. Aleksandra Andrzejowska^1,2, M.Sc. Daniel Jakubiec^2,1, Ph.D. Karol Kubat¹, M.Sc. Tomasz Kowalski³, Professor Maria Olech^4,5, Professor Kazimierz Strzalka^6,7, Professor Angelica Casanova-Katny⁸

¹Institute of Physics, Jagiellonian University, Cracow, Poland. ²Doctoral School of Exact and Natural Sciences, Jagiellonian University, Cracow, Poland. ³Henryk Niewodniczański Institute of Nuclear Physics,Polish Academy of Sciences, Cracow, Poland. ⁴Institute of Botany, Jagiellonian University, Cracow, Poland. ⁵Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. ⁶Malopolska Centre of Biotechnology, Jagiellonian University, Cracow, Poland. ⁷Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Cracow, Poland. ⁸Faculty of Natural Resources, Catholic University of Temuco, Temuco, Chile

Abstract

The gaseous phase rehydration processes of extremely dehydrated lichenized fungi were studied using ¹H-NMR and sorption isotherm. Two species were collected on Atacama desert, Niebla tigrina (Follman) Rundel & Bowler and Roccelina nigricans, from Las Lomitas area of the Parque Nacional Pan de Azucar, Chanaral, during the Atacama Desert expedition, November 2017, whereas three other species were collected on Southern Shetland Islands (one, Caloplaca regalis (= Gondwania regalis) from site on rocks of Deception Island, and two species, Psoroma hypnorum, and Umbilicaria antarctica, from Robert Island, February, 2018, during 54. ECA, Expedition Cientifica Antartica.

The investigated lichens from maritime Antarctica and from Atacama desert reveal the presence of three bound water fractions: very tightly bound water, tightly bound water, and loosely bound water fraction, with the values of hydration times varied for different species.

As compared to Antarctic species (Umbilicaria antarctica Frey & I. M. Lamb, Psoroma hypnorum, and Caloplaca regalis) water soluble solid fraction level in Atacama Desert species is strongly reduced (for Niebla tigrina (Follman) Rundel & Bowler) or completely absent (as for Roccelina nigricans).

Acknowledgements

The research was carried out as a part of Chile grant from INACH (Instituto Antártico Chileno, Ministerio de Relaciones Exteriores, Chile): Sistema de Proyectos INACH, RT_27_16; Concurso: Título: XXII Concurso National de Proyectos de Investigación Científica y Tecnológica, Antártica, 2016, Project: "Ecophysiology of Antarctic and Atacama desert lichens: freezing and deep dehydration mechanism under natural conditions and under passive warming experiments", Investigador Principal prof. Angélica Casanova-Katny, Universidad Católica de Temuco, Temuco, Chile.

References

[1] H. Harańczyk, K. Strzałka, K. Kubat; A. Andrzejowska; M. Olech, D. Jakubiec; P. Kijak; Angelica Casanova-Katny, 2021, Extremophiles, 25(3), 267-283.

533

Extensive time markers sounded by radar across Ferrigno Ice Stream, West Antarctica

Mr Harry Davis¹, Professor Robert Bingham¹, Dr Andy Hein¹, Professor Anna Hogg², Dr Carlos Martín³, Dr Elizabeth Thomas³

¹University of Edinburgh, Edinburgh, United Kingdom. ²University of Leeds, Leeds, United Kingdom. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Marine ice-sheet basins have been shown to be particularly vulnerable to retreat and have significant potential to contribute to global sea-level rise. Several such basins underlie Ellsworth Land, where the West Antarctic Ice Sheet (WAIS) merges with the Antarctic Peninsula Ice Sheet. Significant dynamic thinning and retreat of ice are underway around Ellsworth Land, yet the region remains relatively data-poor for informing estimates of past and future retreat rates and sea-level contributions. Satellite observations provide only a relatively short record of glaciological change, so we are working to extend this record into past centuries by examining the radar-imaged internal structure of Ellsworth Land. By tracing internal-reflection horizons through a series of ground-based and airborne radar traverses spanning Ferrigno Ice Stream, we have identified extensive time markers that link to dated englacial stratigraphy previously traced across the WAIS. The dated englacial stratigraphy can be used to inform future modelling studies to estimate ages of other isochrones, and thus improve our understanding of the potential contribution of the WAIS on future sea level.

534

Physiological parameters and their relationship to diet composition of Antarctic shag (Leucocarbo bransfieldensis) at two sites with different histories of commercial fish exploitation.

Phd Marianela Beltran¹, Phd Veronica D’Amico², Phd Marcelo Bertellotti²

¹Instituto Antartico Argentino, Buenos Aires, Argentina. ²CESIMAR (CONICET), Puerto Madryn, Argentina

Abstract

Anthropogenic factors such as overfishing have a major impact on the structure and dynamics of marine ecosystems. In the past decades, commercial fishing in Antarctica has led to significant declines in the abundance of several stocks of demersal fish species, which has significantly impacted the populations of top predators, including seabirds. The Antarctic Shag (Leucocarbo bransfieldensis) is the only Antarctic seabird species that feeds exclusively on demersal fish and is particularly sensitive to changes in the prey availability in the foraging area. Blood parameters are useful in assessing the physiological status of wild bird populations. These parameters can be affected by environmental changes such as changes in the quality and availability of food resources. In this work, physiological parameters (glucose, cholesterol, triglycerides, protein totals, the leukocyte profile, the heterophil/lymphocyte ratio, and hematocrit) were obtained for Antarctic shag at two breeding sites: Harmony Point, Nelson Island, South Shetland Islands (62°18’S, 59°12’W) (HP), an area affected by commercial fishing, and at the Danco Coast (64°42′S, 62°0′W) (DC), an area without commercial fish fishing, during 2016 and 2018 breeding season, respectively. We also assess dietary composition at bout sites through the pellet analysis. The composition of secondary fish prey varied among sites, with the shags in the impacted area feeding on potentially less profitable prey. H/L proportion and hematocrit were significantly higher at HP, possibly related to increased foraging effort and stress at a site with a poorer trophic supply. HP shags exhibited higher levels of glucose and total proteins, which may be related to stress and dehydration in the context of poorer foraging conditions. These results may contribute to a better understanding of the relationship between prey availability and population trends in Antarctic shag, and the impact of fishing on Antarctic top predators.

536

Spatial and temporal variations in density and distribution of fin and humpback whales in the Bransfield Strait, northern Antarctic Peninsula

Dr Elisa Seyboth^1,2, Dr Eduardo Secchi²

¹University of Pretoria, Hermanus, South Africa. ²Universidade Federal do Rio Grande, Rio Grande, Brazil

Abstract

The Bransfield Strait is part of baleen whales feeding ground in the Southern Ocean. Climate variabilities have been changing its ecosystem during the last decades, with consequences to prey availability for them. Consequently, changes in the distribution of these animals can be expected. Data from the Brazilian Antarctic Program (PROANTAR) collected aboard the Polar Vessel Almirante Maximiano during the austral summer (February-March) between 2013 and 2018 during line-transect surveys were analysed to track for such potential changes. Specifically, spatial and temporal variations in the density of fin (Balaenoptera physalus) and humpback (Megaptera novaeangliae) whales in the Bransfield Strait were investigated using Generalized Additive Models (GAMs). The densities of the species were estimated based on detection functions modelled for each of the species by pooling the sightings of all years and using conventional (CDS) and multiple covariate (MCDC) distance sampling methods. Mean densities were 0.3 (±1.6) and 0.7 (±3.4) for fin and humpback whales, respectively. Selected models indicated that higher densities of fin whale were found in lower latitudes of the study area and that annual variation in the densities occurred for both species. Fin whales seem to be performing a southward movement over the last few years, as well as increasing densities over time in the study area. This work provides new information on density trends of the two most frequently sighted baleen whale species in the Bransfield Strait and can be used to improve estimates regarding krill requirement by its predators. That is relevant to the definition of catch quotas by the Committee for Conservation of Antarctic Marine Living Resources (CCAMLR). Also, it can serve for ongoing discussions on the creation of new marine protected areas in the Antarctic region.

537

From Pixels to Phyla: Detection of Southern Ocean Taxa Using Computer Vision for Biodiversity Monitoring

Dr Cameron Trotter, Dr Huw Griffiths, Dr Rowan Whittle

British Antarctic Survey, Cambridge, United Kingdom

Abstract

For most of human history our knowledge of what lives on the seafloor has relied on nets or devices to bring benthic organisms to the surface. However, utilising these methods for biodiversity monitoring is intrinsically destructive and fails to provide insight into community structure. The development of technologies such as towed camera systems or autonomous underwater vehicles now allow humans to monitor benthic environments in situ, enabling a non-destructive way of understanding community distributions, structure, and function. However, the rapid development of these tools has led to increasing volumes of images being collected. Labelling these images can be extremely resource intensive and require expert knowledge of the monitored ecosystem, resulting in a data bottleneck.

To help combat this, we present a system for the detection and classification of taxa present in Southern Ocean benthic imagery through the use of deep computer vision models. Trained using only a small subset of labelled images captured from a downward facing towed camera, the system is able to accurately identify and localise a range of benthic taxa to a variety of taxonomic levels. Once trained, the system is capable of operating over other unlabelled imagery in an autonomous manner, requiring only human verification of system output. This allows analysis to be performed both faster and over a larger spatio-temporal range when compared to a fully-human approach. The proposed system workflow is adaptable for use in other benthic regions where environmental or capture conditions may vary.

539

Comparison of Aerosol Optical Depth from Satellite based observation over Ahmedabad region

Mr. Ranjitkumar Solanki, Dr. K Pathal

Sardar Vallabhbhai National Institute of Technology, surat, India

Abstract

Abstract: Aerosol Optical Depth (AOD) observed at Ahmedabad, Gujarat (INDIA), region near the Sabarmati River at the Gulf of Khambhat. Using MODIS, Satellite data for Aerosol Optical Depth (AOD) have been collected from the Giovanni site developed by NASA. Results of the data for the 5 years (January to December 2015-2019) have been discussed here. Aerosol Optical Depth characteristics are related to changes in the regional meteorological conditions. The data collected from January to December 2015-2019 indicated annual average AOD variation. The mean annual variations of Aerosol Optical Depth (AOD) indicated maxima around the monsoon. The lowest values of the seasonal mean Aerosol Optical Depth (AOD) observed during the pre-monsoon and relatively moderate AOD were observed during the winter season. Variation of aerosol optical depth (AOD) in the post-monsoon season shows similar variation as of winter and pre-monsoon in 2016. Values increased afterward and reached maxima in both Aqua and Terra observations, which is mostly related to the changes in the local boundary layer.

540

Tracing englacial layers between Dome C and Talos Dome, East Antarctica

Clara Nyqvist¹, Robert Bingham¹, Andrew Hein¹, Neil Ross², Julien Bodart^3,4, Johannes Sutter^3,4, Fausto Ferraccioli⁵, Egidio Armadillo⁶

¹School of GeoSciences, The University of Edinburgh, Edinburgh, United Kingdom. ²School of Geography, Politics and Society, Newcastle University, Newcastle, United Kingdom. ³Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland. ⁴Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland. ⁵National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ⁶DISTAV, University of Genoa, Genoa, Italy

Abstract

Understanding ice-sheet behaviour in relation to changing climate forcing is integral to projecting sea-level rise scenarios under future climate change. The East Antarctic Ice Sheet is the single largest freshwater store on the planet, yet its potential contribution to future sea-level rise remains poorly understood, mainly due to a dearth of accessible palaeoenvironmental constraints to inform ice-sheet modelling. Englacial stratigraphy imaged in radio-echo sounding and dated at intersections with deep ice cores provides information about palaeoclimatic constraints on the ice sheet that can be used to validate numerical modelling. Here, we utilise an extensive dataset of radio-echo sounding, acquired across Wilkes Subglacial Basin and encompassing 61,000 km of profiles, to investigate the englacial architecture of the area. We trace several englacial horizons covering Wilkes Subglacial Basin, and make the first direct englacial stratigraphic connection between Dome C and Talos Dome, enabling us to place provisional age-depth constraints against the ice. The traced stratigraphy also connects with previously traced englacial layers farther across East Antarctica to Dome C, Vostok and the South Pole. These data will be supplied to models to better constrain past ice flow and stability in Wilkes Subglacial Basin.

541

Impact of Waste and Biofouling on Coastal Ecosystems of Antarctica: A Study on Robert Island, South Shetland Islands

Dr. Carla Ximena Salinas^1,2, Laura Johnston^3,4

¹University of St. Andrews, St Andrews KY16 9AJ, United Kingdom. ²Instituto Antártico Chileno, Punta Arenas, Chile. ³University of St Andrews, St Andrews, United Kingdom. ⁴British Antarctic Survey (BAS), Cambridge, United Kingdom

Abstract

Waste accumulation in remote and isolated areas of the planet poses significant challenges due to the difficulty in removal and serves as a vector for the transport and establishment of invasive species. This phenomenon threatens ecosystems with high levels of endemism, especially those in isolated regions. This study aims to analyze the waste found in the coastal ecosystem of the Specially Protected Antarctic Area No. 112, located on Robert Island in the South Shetland Islands, Antarctica Over 700 pieces of debris were collected, with over 80% being plastic, primarily bottles and plastic fragments. Approximately 25% of the plastic waste exhibited biofouling. The study describes the types of debris found and provides insights into the patterns of biofouling associated with plastic waste, with mosses and algae being predominant. The findings highlight the dual impact of waste as a carrier of invasive species in Antarctica's delicate ecosystems, emphasizing the need for effective waste management strategies to mitigate environmental risks in remote and sensitive areas.

543

ACTIVITIES OF THE NATIONAL COMMITTEE OF THE ASSOCIATION OF POLAR EARLY CAREER SCIENTISTS OF COLOMBIA AS A TOOL FOR INCORPORATION OF SCIENCE AND ANTARCTIC ISSUES IN LOCAL EDUCATION

Dr. Jhon Mojica-Moncada^1,2, Sr. Diego Mojica-Moncada³, Dra. Dalia Barragan-Barrera⁴

¹University of Miami, Miami, USA. ²NOAA, Miami, USA. ³Fundación Malpelo y otros Ecosistemas Marinos, Bogota, Colombia. ⁴Instituto Javeriano del Agua, Pontificia Universidad Javeriana, Bogota, Colombia

Abstract

The Association of Polar Early Career Scientists (APECS) is an international and interdisciplinary non-profit organization, aimed at students and researchers in polar regions, mountain glaciers, and cryosphere, with a presence in more than 77 countries worldwide and almost 4,000 associated researchers, its members include undergraduate, master's, and doctoral students, postdoctoral researchers, professionals, educators, and others. In Colombia, as part of those 77 countries, APECS Colombia is established as a National Committee. Currently, APECS Colombia has more than 100 members from local and international institutions in Colombia who research mountain glaciers and the Arctic and Antarctica. Some of our members are also artists and have joined the Antarctic Colombian Program (PAC) since they participated in scientific expeditions from Colombia to Antarctica. To promote and communicate the Antarctic science in children, APECS Colombia has dipped into educational and research initiatives, which include: 1) the international educational campaign called “Antarctic Flags” in several schools in Bogota and Nuquí, the last one a region far from the urban context. 2) An itinerant exhibition with objects, photos, and items from Antarctica. 3) Participation in Colombian tropical glaciers research, collaborating with the Monitoring Network of the Nevado del Tolima Volcano and the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM). 4) The first Colombian glaciological research in Antarctica in collaboration with local and international institutions, resulting in several dissemination products and scientific articles. 5) Outreach in several academic and non-academic sources such as the Meetings of Latin American Antarctic Historians, Education forums, Revista Digital Fulica, and collaboration with manuscripts for the Antarctic Treaty Consultative Meetings (ATCM), among others. Thus, APECS Colombia wants to spread the word about this kind of association, share our experience, and expand our networking to work on the understanding of polar science with the general community and stakeholders, in Colombia and abroad.

545

Strong correlations of sea ice cover with macroalgal cover along the Antarctic Peninsula: ramifications for present and future benthic communities

Margaret Amsler¹, Charles Amsler¹, Andrew Klein², Aaron Galloway³, Katrin Iken⁴, James McClintock¹, Sabrina Heiser⁵, Alex Lowe⁶, Julie Schram⁷, Ross Whippo⁸

¹University of Alabama at Birmingham, Birmingham, USA. ²Texas A & M University, College Station, USA. ³Oregon Institute of Marine Biology, Charleston, USA. ⁴University of Alaska Fairbanks, Fairbanks, USA. ⁵University of Texas at Austin, Port Aransas, USA. ⁶Smithsonian Institution, Edgewater, USA. ⁷University of Alaska Southeast, Juneau, USA. ⁸NOAA Kasitsna Bay Laboratory, Homer, USA

Abstract

Macroalgal forests dominate shallow hard bottom areas along the northern portion of the WAP. Macroalgal biomass and diversity are known to be dramatically lower in the southern WAP and at similar latitudes around Antarctica but few reports detail the distributions of macroalgae or associated macroinvertebrates in the central WAP. We used satellite imagery to identify 14 sites differing in sea ice coverage but similar in turbidity along the central WAP between 64.8°S and 68.7°S latitude. Divers recorded replicate videos of vertical transects between 5 m and 20-40 m. Fleshy macroalgal cover was strongly, negatively correlated with ice concentration, but there was no significant correlation between macroinvertebrate cover and sea ice. Overall community diversity was negatively correlated with sea ice concentration and positively correlated with fleshy macroalgal cover although macroinvertebrate diversity alone was negatively correlated with macroalgal cover. Changes in macroinvertebrate assemblages and overall community metrics were generally linear with sea ice and macroalgal cover; no sharp, ‘tipping point’ patterns were observed. Nonparametric, multivariate analyses of the overall communities resulted in three site clusters corresponding to high, medium, and low fleshy macroalgal cover. Hindcast projections over the 40-year satellite record based on correlations of ice and macroalgal cover data suggest that macroalgal cover at many sites could have been varying substantially over time. Similarly, based on predicted likely sea ice decreases by 2100, projected increases in macroalgal cover at sites which currently have high ice cover and low macroalgal cover are substantial, often even with only a future 15% decrease in sea ice. Such changes would have important ramifications to future benthic food web structure, which food web tracer studies done in parallel to this work show vary significantly with macroalgal and sea ice cover. These changes also impact how Antarctic macroalgae may contribute to future blue carbon sequestration.

546

I Am Your Past/ Yo soy tu pasado: a dialogue between Amazonia and Antarctica personifying the two ecosystems to raise awareness of the teleconnections between them

Dr Elizabeth Lewis Williams¹, Ms Angela Posada-Swafford²

¹University of East Anglia, Norwich, United Kingdom. ²Independent, Miami, USA

Abstract

‘I am your past’ declares the Amazon to the Antarctic in the first of a sequence of letters from Nieve, snow from the high Colombian Andes, to Thwaites, the Antarctic glacier. Through the correspondence between these two landscapes, in letters, poems, sound and visual arts, Nieve and Thwaites will teach one another about the realities of their changing landscapes. ‘Yo soy tu pasado’ is a multi-lingual, multi-format storytelling project mediated by science, which aims to raise awareness of the teleconnections between the two ecosystems, and the threats to them posed by anthropogenic climate change and ecological damage.

A recent study by Bruce Tranter and Elizabeth Leane into public support for Antarctic science (Antarctic Science 2023) has suggested that there are greater challenges in communicating the benefits of projects which are less easy to visualise and understand in terms of practical purpose, such as the complexities involved in these teleconnections. By representing these through the developing relationship of two characters, we aim to enable audiences and readers to make an emotional connection with the two ecosystems. People only protect what they care about, David Attenborough has observed, and they only care about what they know.

Climate change is a global emergency, and also the epic narrative of our age. Its scale challenges conventional forms of storytelling, and requires presentation in the language of both the sciences and the arts. Threaded through our narrative are poems which explore geophysical interactions, and patterns in nature, calling on the oral tradition of poetry as a means of explaining the universe and our place within it. We propose a reading of work in progress, to demonstrate the variety of approaches we take, and to invite scientists to collaborate with us to develop the project with an accurate foundation in science.

549

In silico evidence for modulation of Descampsia antarctica and endophytic Agreia interaction by prophages

Lic. Nicolas Napolitano^1,2, Dr. Francisco Massot^2,3, Dr. Juan Orlowski^1,3, Dr. Cecilia Quiroga⁴, Dr. Walter Mac Cormack^2,3, Dr. Lucas Ruberto^1,2,3, Dr. José Luis Lopez⁵

¹Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ²Instituto Antártico Argentino, Buenos Aires, Argentina. ³Universidad de Buenos Aires and Instituto de Nanobiotecnología, NANOBIOTEC UBA-CONICET, Buenos Aires, Argentina. ⁴Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Buenos Aires, Argentina. ⁵Cátedra de Virología, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Buenos Aires, Argentina

Abstract

Plants rhizosphere harbors a complex microbiome, however little is known about the role of phages in this ecosystem. This work focused on the rhizosphere of Deschampsia antarctica, its endophytic bacteria of the Agreia genus isolated in culture and prophages included in their genomes. We investigated the host-virus gene interaction (lysogeny) and host defense systems using the complete genomic sequences of Agreia CGGE2_1 and Agreia CGGE2_18.

Prophages were detected using Prophage Hunter and Phabox. The proviral genes were annotated using ORF Finder. ORFANS genes were characterized using Predict Protein. Antiviral defense systems in the bacterial genome were detected using PADLOC.

Agreia CGGE2_1 contained a 15499bp taxonomically unknown prophage (Prophage Hunter score=0.96; PhaBox score=1). Agreia CGGE2_18, contained a 21675 bp prophage (Prophage Hunter score=0.97; PhaBox score=0.999) of the family Vilmaviridae [taxonomic assignment was supported by the molecular phylogeny (Maximun Likelihood) of the integrase gene]. Agreia CGGE2_1 genome contained gabija, DMS_other, retron_outgroup, and RM Type II antiviral defense systems. Agreia CGGE2_18 contained the antiviral defense systems dXTPase, RM_Type_IIG, retron_outgroup and RM_Type_II. No CRISPR-Cas systems were detected in either of the two Agreia strains.

About a quarter of genes detected in the prophages were associated with structure and replication, but the rest were Auxiliary Metabolic Genes that could affect host metabolism. These genes were analyzed using Protein Predict and some probable functions were assigned. It is noteworthy that protein binding (58%-61%), DNA binding (11%-20%), RNA binding (13%-8%) and the presence of transmembrane domains (signal peptide) (18%-11%) were among the most common predicted functions, respectively on each of the prophage candidates. In addition, the presence of disulfide bridges was widely associated with proteins without viral homologs.

Putative structures and functions inferred in silico from prophage auxiliary gene sequences constitute preliminary evidence of prophage-bacteria-root interactions that has been poorly described so far.

551

Rock glacier kinematics in the Valles Calchaquíes region, Northwestern Argentina, from multi-temporal aerial and satellite imagery

Dr. Jan Blöthe¹, Dr. Daniel Falaschi², Dr. Sebastian Vivero^3,4, Dr. Takeo Tadono⁵

¹University of Freiburg, Freiburg, Germany. ²Instituto Argentino de NIvología, Glaciologia y Ciencias Ambientales, Mendoza, Argentina. ³University of Fribourg, Fribourg, Switzerland. ⁴University of Lausanne, Lausanne, Switzerland. ⁵Earth Observation Research Center, Tsukuba, Japan

Abstract

In semiarid mountain ranges, rock glaciers constitute an important part of the periglacial environment that is under threat in a changing climate. However, quantitative data on the state of rock glacier activity remain scarce, despite their role in assessing climate change impacts on high-mountain permafrost environments. Here, we derive kinematic information on rock glaciers located in the Valles Calchaquíes district in the Desert Andes of Argentina from optical feature tracking in historical aerial photographs, ALOS PRISM, and CBERS-4A imagery. Using rock glacier outlines published in the National Glacier Inventory of Argentina, we quantify surface movement of 35 landforms for three epochs between 1968 and 2023, and of 140 landforms for two epochs between 2009/2010 and 2023. To overcome matching difficulties resulting from varying image quality and lighting conditions associated with the use of multiple sensors over five decades, we make use of directional filters to enhance feature-tracking performance. We find the mean surface velocities exceeding the limit of detection of our analysis to fall between 0.28 and 0.70 m yr^-1 for all three epochs. Classifying all surface displacement values into kinematic categories reveals that between 60 and 83% of moving areas have velocities between 0.03 and 0.3 m yr^-1. In either case, the rock glacier velocities found for the Valles Calchaquíes are significantly slower than previously reported from other Andean environments. Analysing data from more than five decades, we do not find a coherent picture of permafrost degradation in the region, but rather a coexistence of rock glaciers characterized by accelerating, decelerating, and constant velocities in close vicinity. Our study provides the first quantitative information on rock glacier kinematics for multiple landforms in the Desert Andes of Argentina, contributing important information to assess the impacts of climate warming on this remote periglacial environment.

552

World Climate Research Program's Climate and the Cryosphere Core Project in the Antarctic

Meghan Taylor^1,2, Keith Alverson^1,2, Katie Quigley^1,2, Robert DeConto², Edward Hanna³, Amy Lovecraft⁴

¹Climate and the Cryosphere Core Project, Amherst, USA. ²University of Massachusetts, Amherst, USA. ³University of Lincoln, Lincoln, United Kingdom. ⁴University of Alaska, Fairbanks, USA

Abstract

Climate and the Cryosphere (CliC) is a core project of the World Climate Research Program (WCRP) that works through dedicated initiatives, experiments, scientific advisory committees, and panels. CliC comprises a global community of researchers with expertise in the cryosphere and its interactions with climate and society. Our goal is to identify key research priorities and challenges pertaining to the cryosphere, and to coordinate international cooperation to help address these gaps. CliC also works to emphasize the importance of the cryosphere to policy makers, funding agencies, and the general public. Here we will present some of the CliC co-sponsored Antarctic model intercomparison projects, working groups studying sea ice, polar oceans, ice sheet mass balance and projections of sea level rise with ice loss. Looking to the future, CliC is sponsoring new working groups to help assess impacts on human societies of a diminished cryosphere. We always have opportunities for engaging with CliC science activities, international leadership roles, especially for early career researchers.

553

Exploring phenoloxidase production in antarctic fungi for bioremediation and biotransformation potential

Dra. Maria Patricia Peralta^1,2,3, Franco Cressa Frascot^4,5, Lic. Enzo Valentín Pereyra^1,2,3, Dr. Walter Patricio Mac Cormack^1,3,4, Dr. Lucas Adolfo Mauro Ruberto^1,2,3,4, Dra. Maria Martha Martorell^1,2,3

¹Instituto de Nanobiotecnología (NANOBIOTEC, UBA-CONICET), Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ³Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (FFyB UBA), Buenos Aires, Argentina. ⁴Instituto Antártico Argentino (IAA), Buenos Aires, Argentina. ⁵Escuela de Ciencia y Tecnología, Universidad de San Martín (ECyT UNSAM), Buenos Aires, Argentina

Abstract

Oxidative stress in Antarctica is a relevant phenomenon due to the extreme environmental conditions present in this polar region, particularly due to high levels of UV radiation during the summer. The weakened ozone layer over the region allows more UV radiation to reach the surface, generating reactive oxygen species (ROS), and causing oxidative damage to cells. Low temperatures in Antarctica can also contribute to oxidative stress. Biochemical reactions tend to slow down at colder temperatures, affecting the redox balance and increasing ROS formation.

Past and present human activity in Antarctica has introduced heavy metals into the environment. These metals can act as catalysts in ROS formation, intensifying oxidative stress in organisms. To counteract oxidative stress, Antarctic organisms developed evolutionary adaptations and defense mechanisms. These adaptations are key strategies to mitigate the harmful effects of oxidative stress, allowing Antarctic organisms to survive and thrive in such a harsh environment.

Phenoloxidase enzymes are essential in biotransformation involving the synthesis of specific chemical products, and play a significant role in bioremediation processes, contributing to the degradation and removal of pollutants from the environment.

In our study, we utilized fungal strains isolated during the summer campaign of 2018/2019 to the production of phenoloxidase enzymes using Tannic acid. The detection method is based on the ability of phenoloxidases to oxidize tannic acid, generating colored products. These enzymes catalyze the oxidation of phenols to quinones, and the resulting reaction is visualized through the formation of colored compounds. A dark halo around fungal colonies indicates the presence of enzymatic activity in the studied strains. In this study, out of the 98 strains evaluated, 40% exhibited positive phenoloxidase activity. This relatively high percentage of positivity, suggests that these enzymes are useful for life in cold environments.

554

First record of Psychoda albipennis (Zetterstedt, 1850) in King George Island: A new non-native species with high invasive potential.

MR Jordan Hernandez^1,2,3,4, Dr Hugo A Benítez^2,4,3, Dr Tamara Contador^5,2,6, Dr Sanghee Kim⁷, Dr Claudia Maturana^2,6, Ms Melisa Gañan^5,3,2, Dr Peter Convey⁸

¹Programa de Doctorado en Salud Ecosistémica, Universidad Católica del Maule, Talca, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile. ³Cape Horn International Center (CHIC), Puerto Williams, Chile. ⁴Laboratorio de Ecología y Morfometría Evolutiva, Talca, Chile. ⁵Wankara Laboratory of Antarctic and Subantarctic Freshwater Ecosystems, Puerto Williams, Chile. ⁶Cape Horn International Center (CHIC), Universidad de Magallanes, Puerto Williams, Chile. ⁷Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Incheon, Korea, Democratic People's Republic of. ⁸British Antarctic Survey (BAS), Natural Environment Research Council, Cambrige, United Kingdom

Abstract

Alien species represent one of the main threats to the biodiversity and ecosystem health, especially those with simple community structures and little interspecific competition, such as the Antarctic continent. Antarctica stands out as one of the most pristine regions on a global scale, with high levels of endemism, geographic isolation, and evolutionary isolation. Despite this, climate change and increased human activities on the continent contribute to the introduction of alien species. Currently, it is estimated that there are approximately 200 invasive species established in Antarctica and the sub-Antarctic islands, of which around 30% are insects. Specifically in Maritime Antarctica, a new non-native species Psychoda albipennis, was reported as a potential invader in recurrent sightings between 2022 and 2023 (Benítez and Contador, Pers. Obs.) have been observed on King George Islands. Given that the region has only two native insect species, Parochlus steinenii and the endemic Belgica antarctica. The increase of non-native species in this Antarctic region has been a cause for alarm and of great interest in the context of biological invasions. Although it is crucial to pay attention to all introduced species, the most recent, Psychoda albipennis, seems to stand out among the other introduced dipterans. It has been observed breeding on mosses, suggesting a greater invasive potential and ability to establish outside Antarctic research stations. This research is the first report of the dipteran Psychoda albipennis on King George Island, confirming its identity by DNA barcoding, and provides the first record of an alien species in the wild in the South Shetland Islands.

555

Partitioning of the noble gases between sea ice and seawater in laboratory freezing experiments

Laura Glastra, Dr. Brice Loose

University of Rhode Island, Graduate School of Oceanography, Narragansett, USA

Abstract

During sea ice formation, most impurities in water are excluded from the ice Ih crystal lattice, however there is theoretical and empirical evidence to show that small molecules like H₂ and He become incorporated into the ice. The sea ice-seawater partition coefficient (k_iw) is a term used to quantify the partitioning of solutes during freezing. A value of k_iw > 1 indicates more solute ends up in the ice, whereas a value of k_iw < 1 signifies that more solute is channeled to the seawater. Despite the inherent value of being able to quantify the partitioning of dissolved impurities (e.g., gases and pollutants), there are very few high confidence measurements of k_iw, beyond the results for bulk salts. Even less is known about how k_i_w varies for different ice types and growth rates.

This work seeks to fill this knowledge gap, beginning with the five stable noble gases, which cover a wide range of molecular sizes and exhibit diverse physical characteristics in seawater. Because of their divergent behavior, the noble gases are conservative tracers that can provide unprecedented detail into the freshwater and air-sea processes. This includes the ability to fingerprint sea ice formation and glacier basal melt in Dense Shelf water and Antarctic Bottom Water (AABW).

We conducted freezing experiments using a gas-tight enclosure with a cold head to induce surface freezing and measure k_iw across a range of ice growth rates. As with salt, faster growth rates lead to more incorporation of noble gases into the ice, thus higher k_iw. For example, increasing the ice growth rate from 0.6 to 17 cm/day leads to a 186% increase in k_iw for Xe, and 66% increase for Ne. These results indicate that impurities not only partition by size, but respond uniquely under different conditions of sea ice formation as well.

556

Antarctic Macroalgae: Applying Species Distribution Models to estimate Blue Carbon standing stocks

Dr. Camila Neder^1,2, Dr. Dolores Deregibus^3,4, Lic. Carolina V. Matula⁴, Dr. Gabriela L. Campana^4,5, Hendrik Pehlke⁶, Dr. Kerstin Jerosch⁶, Dr. María Liliana Quartino⁴

¹Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Cs. Exactas Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Córdoba, Argentina. ³Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ⁴Instituto Antártico Argentino -Dirección Nacional del Antártico (IAA-DNA), Buenos Aires, Argentina. ⁵Universidad Nacional de Luján (UNLu), Buenos Aires, Argentina. ⁶Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

Abstract

The West Antarctic Peninsula has been identified as highly vulnerable due to rising temperatures and increased anthropogenic carbon emissions impacting its biodiversity. Glacier retreat is one of the identified responses, opening up newly ice-free areas available for colonization but also changing the environmental conditions due to meltwater input, sediment runoff, and ice impact. A habitat is characterized by the combination of environmental parameters that support carbon cycling within a specific blue carbon ecosystem, such as macroalgal forests Species Distribution Models (SDMs) are an efficient tool to link environmental parameters with species presence/absence to identify their habitat suitability and distribution. What if the tool allows us more? We aim to potential carbon standing stock expansion in the ice-free areas opened over the last six decades of glacial retreat in an Antarctic fjord ecosystem, based on the determination of habitat suitability of macroalgae species. This study focuses on the SDMs Chlorophyta, Rhodophyta, and five Phaeophyceae species, projecting macroalgae habitat suitability by species-specific ensemble modeling in the Potter Cove fjord. Further estimations of macroalgal expansion and colonization, as well as potential carbon stocks, were conducted through SDMs results, binary transformation, data from published in-situ abundance quadrat surveys, and conversion factors. From 1956 to 2020 Fourcade Glacier opened up ~1,6 km² free of ice. Our estimation of macroalgal colonization during this period at Potter Cove shows an expansion of ~0.42 km² with a total carbon standing stock of 9.73 ± 6.32 tons of C. Through the integration of SDMs and field data, this research provides valuable insights into the dynamic relationship between Antarctic macroalgae, environmental changes, and carbon stocks, contributing to the broader understanding of ecosystem dynamics in the face of global climate change.

557

Gateway to Antártica: Unveiling the Future of Inclusive and Interdisciplinary Antarctic Research at the International Antarctic Center

Mr. Alejandro Font, Mr. Ricardo Faundez, Mr. Fernando Bahamodez, Mr. Jaime Paredes, Mr. Daniel Ramirez, Mr. Sebastian Menendez

Instituto Antartico Chileno, Punta Arenas, Chile

Abstract

The International Antarctic Center (CAI), located in Punta Arenas, Chile, epitomizes cutting-edge interdisciplinary and equitable scientific collaboration, focusing on Antarctic and sub-Antarctic research. This pioneering project aims to foster a diverse and inclusive community of scientists by providing state-of-the-art facilities and support systems for research across various disciplines, including ecology, evolution, cryosphere studies, atmospheric sciences, biotechnology, geology, and paleontology.

The CAI's comprehensive infrastructure includes advanced laboratories equipped for a wide range of scientific investigations, facilitating groundbreaking research in the harsh conditions of the Antarctic region.

Moreover, the CAI's logistical facilities are designed to support extensive Antarctic expeditions, offering a strategic gateway for international researchers to conduct fieldwork in the Antarctic and sub-Antarctic areas. With its strategic location, the CAI will serve as a critical hub for distributing personnel, equipment, and samples, ensuring efficient and safe research operations across the Antarctic Peninsula. The center's commitment to sustainability and environmental stewardship is evident in its construction and operations, aligning with global efforts to mitigate the impacts of climate change.

The CAI's role extends beyond research. Through educational and cultural initiatives, it aims to increase global awareness and appreciation of Antarctic values. By engaging with the community, the CAI promotes a deeper understanding of the Antarctic's significance in global environmental systems, encouraging scientists and future generations to pursue research in this unique and vital region.

This holistic approach advances scientific knowledge and strengthens the global scientific community's capacity to address urgent challenges, such as climate change and biodiversity loss. The CAI exemplifies how scientific institutions can significantly contribute to building welcoming, equitable, and inclusive research communities by fostering collaboration and promoting diversity and inclusion.

558

Changes in benthic macrofaunal communities in Arthur Harbor, Anvers Island in response to glacial retreat and changes in sea ice cover

Dr Terry Palmer¹, Dr. Jennifer Beseres Pollack¹, Mr. Larry Hyde¹, Dr. Andrew Klein², Dr. Paul Montagna¹, Mr. Stephen Sweet²

¹Texas A&M University-Corpus Christi, Corpus Christi, USA. ²Texas A&M University, College Station, USA

Abstract

Arthur Harbor, adjacent to Palmer Station, Anvers Island has been exposed to major environmental changes, including substantial glacial retreat and reductions in sea ice cover occurring since at least the 1950s, and exposure to Antarctica’s largest oil spill from the grounding of the Bahía Paraíso ship in 1989. The effects of such environmental changes are often detected in environmental bioindicators, such as benthic macrofaunal communities. However, it is uncertain if these changes had any effect on macrofaunal communities occurring at medium depths (~70 m) within the photic zone. In this study, infaunal communities at three relatively shallow (65 to 73 m) locations were compared with communities previously characterized in 1971 (by Richardson and Hedgpeth 1977), and in 1989 (Hyland et al. 1994) to determine if any community changes could be detected. Challenges included having different sampling techniques and incomplete data reporting for community characterizations in 1971 and 1989.

559

Screening for cold-adapted lipases and proteases

Dra. Maria Patricia Peralta^1,2,3, Agustina Klin^4,5, Jimena Lucía Godoy^4,5, Lic. Enzo Valentín Pereyra^1,2,3, Dr. Walter Patricio Mac Cormack^1,3,4, Dra. Maria Martha Martorell^1,2,3, Dr. Lucas Adolfo Mauro Ruberto^1,2,3,4

¹Instituto de Nanobiotecnología (NANOBIOTEC, UBA-CONICET), Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ³Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (FFyB UBA), Buenos Aires, Argentina. ⁴Instituto Antártico Argentino (IAA), Buenos Aires, Argentina. ⁵Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEN UBA), Buenos Aires, Argentina

Abstract

In cold environments like Antarctica, lipases, and proteases adapted to low temperatures play a pivotal role allowing the breakdown of lipids and proteins. These enzymatic activities are crucial for acquiring essential molecules, contributing significantly to the nutrient cycle, organism adaptation, and survival in resource-limited ecosystems. Beyond their ecological importance, these enzymes showcase substantial potential for biotechnological applications, particularly in industries operating at moderate to low temperatures.

The successful activation of the fungal strain bank from the 2019 summer expedition in Carlini Station, involved the recovery of 98 strains with a remarkable 100% success rate. Conservation methods included storing strains in glycerol at -80°C to ensure prolonged viability and genetic stability and Vaseline at 4°C. Additionally, water at 4°C was employed as an alternative conservation technique, providing short-term options and easy accessibility.

The strains were evaluated for protease and lipase activity. Rhodamine B, a fluorescent dye sensitive to fatty acids, was used to assess lipase activity. The assay, involving olive oil and Rhodamine B, showcased the hydrolytic capability of lipases through the liberation of fatty acids and subsequent fluorescence. Determining protease activity using agar milk plates presented a qualitative method for assessing the hydrolysis of milk proteins by microorganisms, particularly fungi. The formation of clear zones around fungal colonies on these plates indicated the ability of the microorganisms to produce protease enzymes capable of breaking down milk proteins.

The comprehensive results from the study highlight significant enzymatic potential among the fungal isolates, with 60% exhibiting positive protease activity and 25% demonstrating positive lipase activity at low temperatures. These findings advance our understanding of microbial ecology in extreme environments and offer promising avenues for harnessing the enzymatic capabilities of these fungi in various biotechnological and industrial applications.

560

Bioprospecting of secondary metabolites produced by Antarctic fungi under biological stress

Lic. Enzo Valentín Pereyra^1,2,3, Dra. Maria Patricia Peralta^1,2,3, Dr. Walter Patricia Mac Cormack^1,3,4, Dra. Maria Martha Martorell^1,2,3, Dr. Lucas Adolfo Mauro Ruberto^1,2,3,4

Abstract

Natural molecules display greater structural diversity than those derived from chemical synthesis, showcasing a spectrum of potential biological activities. Co-cultivation stands out among methodologies used to discover novel natural antimicrobial compounds. This process involves cultivating two or more microorganisms in a shared environment, inducing biological stress that can stimulate the synthesis of secondary metabolites, being a promising way for the development of novel drugs. The objective of this study was to evaluate antimicrobial activity through sensitivity assays of extracts obtained from the co-cultivation of three strains of Cadophora sp., isolated from Base Carlini, Isla 25 de Mayo, Antarctica. Co-cultures were performed by juxtaposing two strains per plate, generating all possible combinations among the three strains on potato dextrose agar (PDA). Three different treatments were assayed: 1) Both strains cultivated on the plate from day 0. 2) Anoxic culture for 7 days, followed by the addition of the competitor. 3) Anoxic culture followed by the addition of the competitor at 14 days. After 28 days of incubation, fungal biomass was removed, and agar was preserved for extraction. Ethyl acetate was used as an extraction solvent. Concentration was done in a rotary evaporator. These extracts were subsequently evaluated in sensitivity tests against Candida. albicans and Aspergillus fumigatus. Sensitivity assay results are promising, with some extracts (CC, AT7, ET7, CT14, AT14, ET14, FT14) showing a larger inhibition zone than the average, suggesting a significant inhibitory activity against C. albicans. Furthermore, a growth reduction of up to 40% in the superficial mycelium of strain C1 was observed when was co-cultured with C3, illustrating competitive effects.

562

The Campo de Hielo Sur: A decadal window on Pedoclimate Monitoring at Torres del Paine National Park, Chile

Prof Eduardo Senra¹, Prof Carlos Schaefer², Prof Márcio Francelino², Prof Guilherme Correa³, Dr Hugo Cândido², Prof Roberto Michel⁴

¹Universidade Federal de Uberlândia, Monte Carmelo, Brazil. ²Universidade Federal de Viçosa, Viçosa, Brazil. ³Universidade Federal de Uberlândia, Uberlândia, Brazil. ⁴UESC, Ilhés, Brazil

Abstract

At the edge of the world's third-largest continental ice field (Campo de Hielo Sur) lies a region with unique landscapes and ecosystem-soil relationships that are poorly understood. Over a decade of pedoclimatic monitoring along a toposequence within Torres del Paine National Park, we revealed the intricate nuances of the Andean ecosystems and their climatic variations. Focusing on three distinct sites — Periglacial areas (Andean Tundra, 1010m), the Páramo (850m, above the tree line), and Forests (Nothofagus spp., 650m) — we strategically installed soil temperature and moisture sensors at depths ranging from 5 to 100 cm. The thermal regimes of the sites varied in the amplitude of fluctuations, but all exhibited a warming trend over the analyzed time series. The high periglacial zone had the largest variations in amplitude and did not have permafrost. However, significant differences were observed in soil water content and temperature dynamics. These variations were attributed to factors such as vegetation cover, climate, geomorphic characteristics, and specific soil attributes in each ecosystem type. Our results underscore the warming trend at all sites. However, assessing the impact of climate change on soil processes and ecosystem health in mountain environments should consider ecosystem diversity. Furthermore, our study provides valuable insights into the complex interactions between climatic factors, soil properties, and ecosystem dynamics in extreme environments, such as those found in this wet sector of Patagonia.

563

Assessing Soil Formation Processes on King George Island

Dr. Francisco Najera^1,2, Dr. Francisco Matus¹, Dr Mario Fajardo³, Ms Natalia Zumelzu¹, Dra. Carolina Merino¹

¹Universidad de La Frontera, Temuco, Chile. ²BIOREN, Temuco, Chile. ³Sydney University, Sydney, Australia

Abstract

The interaction between biota and pedogenic factors on Marine Antarctica Island still requires further attention. Processes such as rubification, which is a stage of pedogenesis involving the release of iron from primary minerals to form free iron oxides coating mineral particles, as well as melanization and cryoturbation, among others, affect soil formation and carbon sequestration in response to rapid environmental changes. E.g. rubification, related to the movement of iron under redox conditions, has not been thoroughly studied in Antarctic environments where redox conditions prevail. This study aims to investigate the soil formation process in the Fildes and Barton Peninsulas on King George Island. The goal is to identify the chemical and microbial activities contributing to these processes. Fourteen soil pits were excavated, including moraine soils inland and Ornithosols on the coast. Soil spectra were analyzed using MID-FTIR to determine the presence of Fe, Al, and Mn minerals, soil texture, pH, organic carbon (C), total nitrogen (N), available phosphorus (P), and other exchangeable cations, as well as organo-mineral complexes of Fe, Aluminum (Al), and manganese (Mn), among other elements. Colonies of mesophilic bacteria, including free aerobic N fixers, P solubilizers, and K solubilizers, were also studied. Our results indicate that soil mineralogy can be associated with processes such as rubification, where under redox conditions the iron minerals such as goethite (FeO₂H), hematite (Fe₂O₃), and magnetite (Fe₂O₄) were observed in the FTIR spectra. The C availability, fine mineral particles, and metal were related to Al minerals, and a high amount of active Mn forms was observed. In ornithogenic soils, the process of phosphatization is highlighted with mineral-associated P with Al and Fe minerals. Understanding and predicting soil development in the Fildes Peninsula and surrounding areas of King George Island could prove crucial based on the accumulation and availability of these variables

564

Microbial diversity, resistome, and virulome in high-latitude soils from Union Glacier, Antarctica

Patricio Arros¹, Daniel Palma², Matías Gálvez-Silva¹, Alexis Gaete², Hugo González¹, Gabriela Carrasco¹, José Coche¹, Ian Pérez³, Eduardo Castro-Nallar⁴, Cristóbal Galván⁵, Macarena Varas¹, Marco Campos⁶, Jacqueline Acuña⁶, Milko Jorquera⁶, Francisco Chávez³, Verónica Cambiazo², Andrés Marcoleta¹

¹Grupo de Microbiología Integrativa, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile. ²Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile. ³Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile. ⁴Centro de Ecología Integrativa, Universidad de Talca, Talca, Chile. ⁵GEMA, Center for Genomics, Ecology & Environment, Universidad Mayor, Santiago, Chile. ⁶Laboratorio de Ecología Microbiana Aplicada (EMALAB), Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile

Abstract

The high-latitude regions of Antarctica remain among the most remote, extreme, and least explored areas on Earth. Despite the highly restrictive conditions, microbial life has been found in these environments, although there is still limited information on their genetic properties and functional capabilities. Moreover, the accelerated melting of the Antarctic permafrost, the increasing exposure of soils, and the growing human transit pose the question of whether these environments could be a source of health-risk microbes or genetic information that could emerge and cause global health problems. In this line, although a high bacterial diversity and autochthonous multi-drug resistant bacteria were found in Antarctic Peninsula soils, we lack information regarding the resistome of high-latitude areas. Moreover, no previous studies have evaluated the pathogenic potential of microbes inhabiting Antarctic soils. In this work, we combined metagenomic and culture-dependent approaches to investigate the microbial diversity, resistome, virulome, and mobile genetic elements (MGEs) in soils from Union Glacier, a high-latitude cold desert in West Antarctica. Despite the low organic matter content, diverse bacterial lineages were found, predominating Actinomycetota and Pseudomonadota, with the presence of limited archaea and fungi taxa. We recovered more than 80 species-level representative genomes (SRGs) of predominant bacterial taxa and the archaeon Nitrosocosmicus sp. Diverse putative resistance and virulence genes were found among the SRGs and the metagenomic reads and contigs. Furthermore, we found bacterial isolates resistant to up to 24 different clinical antibiotics, mainly Pseudomonas, Arthrobacter, Plantibacter, and Flavobacterium. Moreover, some isolates produced putative virulence factors, including siderophores, pyocyanins, and exoenzymes with hemolytic, lecithinase, protease, and DNAse activity. This evidence uncovers a largely unexplored resistome and virulome hosted by deep Antarctica’s soil microbial communities and the presence of bacteria with pathogenic potential, highlighting the relevance of environmental surveillance in the white continent.

565

The Last Ices of the Andean Tropical Cryosphere: a case study of Huayana Potosi, Bolivia.

Prof Eduardo Senra¹, Prof Carlos Schaefer², Prof Márcio Francelino², Prof Guilherme Correa³, Dr Hugo Cândido², Prof Davi Gjroup²

¹Universidade Federal de Uberlândia, Monte Carmelo, Brazil. ²Universidade Federal de Viçosa, Viçosa, Brazil. ³Universidade Federal de Uberlândia, Uberlândia, Brazil

Abstract

Climate change is exerting unprecedented pressure on the high tropical mountain cryosphere of the Andes, with alarming consequences for ecosystems and local communities. The rapid reduction in the extent and thickness of glaciers is triggering hydrological instability, threatening regional water security, and exacerbating the risk of natural disasters such as landslides and floods. Additionally, intensified erosional processes are compromising slope stability, negatively impacting biodiversity, and the sustainability of human activities. Peatlands, known as Bofedales, are facing erosion and rapid mineralization of organic matter accumulated since the last glacial maximum, undermining their crucial function as carbon sinks and contributing to atmospheric carbon emissions. This phenomenon not only threatens local environmental balance but also has global implications, exacerbating the increase in global warming. During the period from 2015 to 2023, extensive soil climate monitoring was conducted at an altitude of 4800 meters in the Huayana Potosi Mountain, Bolivia. The results revealed a worrying trend of continuous warming, without freezing and thawing cycles, far from the conditions of permafrost occurrence at this altitude, previously considered as a stable limit. The high tropical mountain permafrost is becoming more irregular and discontinuous, with the permafrost line rising to increasingly higher altitudes. These findings emphasize the urgency of adaptive and mitigative actions to protect Andean ecosystems and the associated ecosystem services, as well as to ensure the resilience of local communities to climate change. International cooperation and commitment to sustainable environmental policies are crucial to addressing this global challenge and safeguarding the biodiversity and natural resources of the Andean high tropical mountain regions.

566

Latitudinal Response of Total Electron Content during Storms and Substorms at High Latitudes

Carlos Castillo-Rivera¹, Marina Stepanova¹, Victor Pinto¹, Manuel Bravo²

¹University of Santiago of Chile, Santiago, Chile. ²Adventist University of Chile, Chillan, Chile

Abstract

The study of the impact of auroral activity, particularly associated with geomagnetic storms and substorms, on the high-latitude ionosphere has posed a significant challenge since its discovery. This research area is crucial for space weather prediction, arising from early advancements in understanding the Earth's magnetosphere and its relationship with the ionosphere. Yet, questions persist regarding the mechanisms underlying their interaction. We employ the Global Navigation Satellite System (GNSS) network to calculate the Total Electron Content (TEC). This is done by analyzing signal delays between satellites and GNSS receivers, effectively covering extensive areas including Antarctica, Greenland, Canada, the United States, and Northern Europe. In this study, we analyze the TEC during solar cycle 24 (SC24) and investigate the latitudinal differences in ionospheric TEC across the auroral ovals and polar caps under varying levels of auroral and solar activity, as well as seasonal changes. Our findings highlight the significant impact of geomagnetic storms and substorms on TEC variations. Notably, distinct TEC responses were observed in both hemispheres, along with the identification of annual, semiannual, and 27-day variations. Additionally, we explore correlations between different geomagnetic indices and TEC, revealing stronger correlations during the declining phase of SC24. This research aims to enhance understanding of magnetosphere-ionosphere interactions.

567

ANTOS: Survey of current long-term monitoring and gaps in monitoring efforts in near-shore and terrestrial Antarctic ecosystems

Abigail Borgmeier¹, Byron Adams¹, Dana Bergstrom², Craig Cary³, Steve Colwell⁴, Pete Convey⁴, Vonda Cummings⁵, Dolores Deregibus⁶, Mauro Guglielmin⁷, Soon Gyu Hong⁸, Charles Lee³, Marcela Libertelli⁶, Sharon Robinson⁹, Stefano Schiaparelli¹⁰, Emmanuelle Sultan¹¹, Megumu Tsujimoto¹², Elie Verleyen¹³

¹Brigham Young University, Provo, UT, USA. ²AAD, Kingston, Australia. ³University of Waikato, Hamilton, New Zealand. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵NIWA, Auckland, New Zealand. ⁶Instituto Antártico Argentino, Buenos Aires, Argentina. ⁷Insubria University, Varese, Italy. ⁸KOPRI, Incheon, Korea, Republic of. ⁹University of Wollongong, Wollongong, Australia. ¹⁰Università degli Studi di Genova, Genova, Italy. ¹¹National History Museum, Paris, France. ¹²NIPR, Tokyo, Japan. ¹³University of Ghent, Gent, Belgium

Abstract

In Antarctica, several different biological phenomena have been discovered using monitoring data which has been collected for up to fifty years in some locations on the continent. The goals of these monitoring projects could not have been met without an established baseline of biotic and abiotic factors governing the ecosystem. If there is no baseline of comparison, unusual weather events could be incorrectly interpreted as single anomalies instead of part of the patterns which characterize the continent. Long-term monitoring in Antarctica is essential to document the environmental impact of climatic changes. The Antarctic Near-Shore and Terrestrial Observation System (ANTOS) is a SCAR expert-group whose goal is to coordinate a cross-continent and cross-national program-scale assessment of environmental variability and change, resulting in monitoring data which is comparable and usable by all scientists working in Antarctica. To achieve this goal, the ANTOS group is working to select marine and terrestrial locations on the Antarctic continent which are at high risk of change in the coming decades, where there is interest from the scientific community, or where there is no current monitoring. A series of two surveys was sent to Antarctic researchers from a variety of different scientific programs and disciplines to assess what monitoring is currently occurring on the continent, what environmental changes the monitoring has captured, and what gaps in current monitoring efforts exist. The proposed monitoring sites will be implemented using the guidelines of the ANTOS committee to ensure that the data will be collected in a wholly systematized manner, which will make the data easily comparable across all sites. Proposed sites for future monitoring will be chosen based off a set of criteria which include the biological uniqueness of the habitat, the scientific infrastructure at the site, and the degree of predicted change to occur at that site.

568

Plant communities in felsenmeers under the influence of nesting sites - Harmony Point,Antarctica

Prof Guilherme Corrêa¹, Prof Carlos Schaefer², Prof Jair Putzke³, Prof Pedro Villa⁴, Dr Prímula Viana², Dr Hugo Cândido², Dr Danniela Schmitz², Msc Viviane Koch¹, Prof Eduardo Senra¹

¹Universidade Federal de Uberlândia, Uberlândia, Brazil. ²Universidade Federal de Viçosa, Viçosa, Brazil. ³Unipampa, São Gabriel, Brazil. ⁴Universidade Estadual de Feira de Santana, Feira de Santana, Brazil

Abstract

Maritime Antarctic has one of the main terrestrial ecosystems in the world dominated mainly by lichens and mosses. The main objective of this study was to investigate the organization of plant communities among felsenmeers with active and inactive nesting characteristics in the northern area of the Harmony Point peninsula, Nelson Island, Maritime Antarctica. A total of 70 plots were allocated to evaluate frequency, coverage degree, and the ecological significance index of communities in the felsenmeers areas. Overall, we sampled one macroscopic algae, 12 bryophyte species, 21 lichen species belonging to 19 families. The species Sanionia uncinata forms communities with high levels of ecological significance and the nitrophilic lichen Acarospora macrocyclos is present in all felsenmeers. Four moss carpet communities, two moss carpet/lichen communities and a moss carpet/Prasiola community were identified. For the two environments defined based on the presence or absence of current nesting, the carpeted moss/lichen community was identified. The associations between species in felsenmeers with active nests did not differ from inactive felsenmeers. However, the greatest richness and vegetation cover was observed in places with the activity of birds, pointing to a probable preference of the species and indicating an initial idea of plant succession.

569

Liquid veins in ice: A habitat for microbial life within natural ice formations.

Dr. Carlos Di Prinzio^1,2, Dr. Analia Pedernera¹, Dr. Pastor Achaval¹, Dr. Guillermo Aguirre Varela^1,2

¹Universidad Nacional de Córdoba, Córdoba, Argentina. ²IFEG, Córdoba, Argentina

Abstract

In this study, the stability of unfrozen water at temperatures below the melting point of pure ice was investigated at the triple junction points of grain boundaries within polycrystalline ice (referred to as liquid veins) with different concentrations of NaCl. Contaminated ice polycrystals were grown by freezing a very thin layer of NaCl aqueous solution onto a single crystal of pure ice. The contaminated polycrystalline ice layer was then polished using a microtome within a refrigerated chamber at -20 °C, reducing its size to a few microns. Subsequently, the sample was placed in a thermostatized cell at approximately -10°C for observation using an optical microscope. This setup permitted the capture of photographs of the surface of the contaminated sample, enabling the measurement of ice crystals and the amount of liquid solution present. The volumetric concentration of contaminants in an ice sample is directly proportional to their concentration in the liquid veins, with the proportionality constant being the ratio between the volume of liquid veins and the total volume. Since obtaining the volumes of liquid veins in ice samples is impossible, a two-dimensional model was proposed in this work. It was determined that the proportionality constant could also be obtained by replacing volumes with areas. Additionally, a model for the shape of ice grains was proposed, which could potentially allow for the estimation of the average size of the liquid vein. Liquid veins serve as a habitat for microbial life on Earth and, theoretically, could also function as a habitat on Mars and other cold planetary bodies. The size of these liquid veins plays a crucial role in determining the survival conditions for microorganisms.

571

Grain growth in deep polar ice.

Dr. Carlos Di Prinzio^1,2, Luis Gerez¹, Pablo Valdez¹, Dr. Pastor Achaval¹, Dr. Guillermo Aguirre Varela^1,2

¹Universidad nacional de Córdoba, Córdoba, Argentina. ²IFEG, Córdoba, Argentina

Abstract

In this work, grain growth in ice under pressure was studied. This study will allow a better understanding of grain behavior in deep polar ice. A layer of ultrapure water was placed between two single crystals of pure ice inside a cold room. Freezing the water layer produced a thin polycrystalline layer of ice. The surfaces of the sample were then polished with a microtome and the sample was immersed in silicon inside a pressure chamber. The hydrostatic pressure of the chamber was 100 atm, approximately equivalent to the pressure that polar ice is subjected to at a depth of 1000 meters.

The chamber was placed in a thermostated environment at -7⁰C. A microscope with digital camera was recording the evolution of the grains of the polycrystalline layer of ice. The study temperature is above the temperatures found at 1000 meters depth in polar ice of Antarctica and Greenland. It is planned in the future to put temperatures close to -30⁰C.

The size of some crystals were recorded as a function of time and their evolution was modeled with computational grain growth using Monte Carlo. The studies presented provide a better understanding of the growth rate of grains in polar ice under pressure.

572

Identification of biomass burning sources through the determination of levoglucosan in the cryosphere of the Andes

MSc Fernanda M. Luz^1,2, Dr Filipe G. Lindau¹, Dr Rafael S. dos Reis³, Dr Jefferson C. Simões¹, BS Raimundo F. de Araujo², Dra Sonaira S. da Silva⁴, Dra Elena Argiriadis^5,6

¹Polar and Climate Center, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. ²Thematic Laboratory of Soils and Plants, National Institute of Amazonian Research, Manaus, Brazil. ³Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁴Laboratory of Geoprocessing Applied to the Environment, Federal University of Acre, Acre, Brazil. ⁵Department of Environmental Sciences, Informatics and Statistics, University of Venice Ca’ Foscari, Venice, Italy. ⁶Institute of Polar Sciences (ISP-CNR), Venice, Italy

Abstract

The burning of biomass in South America (SA), whether natural or anthropogenic, occurs on a large scale, impacting the cryosphere and consequently the Andean populations. Levoglucosan (L) and its isomers mannosan (M) and galactosan (G) are unambiguous biomass burning biomarkers (BBB) of cellulose and hemicellulose burning. Large smoke emissions combine with other atmospheric aerosols and can be transported over long distances and high altitudes, contributing to the ubiquity of L and its isomers in different glacial records. Our objective was to identify the origin and distribution of BBB transported and preserved in Andean glaciers. In this study we collected cryoconite and surface snow samples from two glaciers in the Vilcanota mountain range in the southern Peruvian Andes and soils from the Andean Altiplano (AA) and southwestern Amazonia to investigate the BBB. The BBB were determined by gas chromatography-mass spectrometry performed at the University of Venice Ca’ Foscari (Italy). The concentration of L and its isomers were higher in cryoconites from Suyuparina in relation to Quelccaya, with L 23907.02 and 6609.09, M 10864.36 and 3800.73, G 6411.97 and 1608.95 ngg^-1, and the ratio L/M 2.20 and 1.74, respectively. We investigate smoke or BBB trajectories through Hysplit to track advection and weather systems that control BBB transport. Our results identified sources of forest fires and agricultural fires mainly originating in the Amazon Forest, areas of deforestation and AA vegetation. Quelccaya and Suyuparina showed significant differences in BBB concentrations, making it possible to determine differences between sources of grasses, conifers and angiosperms. Studies in Antarctica identified concentrations of BBB from the biomass burning in Africa, Australia and especially SA. This is the first study that identified the origin of BBB in Andean glaciers. Biomass burning also affects the cryosphere of the Southern Andes, our approach contributes to future studies in this region.

573

Structure of culturable bacterial communities from surrounding soils of the Ecology Glacier (King George Island) and the patterns of antibiotic resistance and virulence of isolated strains

Dr. Jacquelinne Acuña¹, Dr. Marco Campos¹, Eng. Constanza Venegas¹, Dr. Francisco Chavez², Dr. Andrés Marcoleta², Dr. Veronica Cambiazo², Dr. Leon Bravo¹, Dr. Milko Jorquera¹

¹Universidad de La Frontera, Temuco, Chile. ²Universidad de Chile, Santiago, Chile

Abstract

As result of climate change, Antarctic Peninsula has been pointed as the most rapidly warming region on the globe. However, the consequences of warming and ice-melting on the soil microbial communities are still poorly understood. In this context, we explored the culturable bacterial communities in surrounding soils of the Ecology Glacier (King George Island). Soil samples of permafrost (P), moraine (M), and rhizosphere (R) were collected during the Chilean’s Antarctic Scientific Expedition (ECA 59) in 2022. Soil bacteria were cultured by traditional plating-method on agar (PMA) and ‘in situ’ cultivation (ISC) by using microwell diffusion chamber. Culturable bacterial lawns communities and 158 genotypically different isolated strains (76 by PMA and 82 by ISC) were purified and characterized by 16S rRNA gene partial sequencing. Isolated strains were also screened by their antibiotics multiresistance (AMR) and virulence factors (VF). Despite that a higher culturable bacterial diversity was observed in R than P and M, our results revealed to phyla Pseudomonadota (55-75%), Actinomicetota (20-35%) and Bacteroidota (5-10%) as the most abundant bacterial taxa in culturable bacterial lawns communities. The isolated strains showed affiliations to 24 different bacterial genera, where Pseudomonadota (76%), Actinomicetota (18%), Bacteroidota and Bacillota (3.2%) were the most dominant taxa. By using ISC, a wider bacterial diversity of less studied genera (such as Bosia, Rathayibacter and Rugamonas) was isolated, but Bacillus was exclusively recovered by PMA. Additionally, the percentages of resistance of isolated strains were 86% beta-lactams, 77% Cephalosporins, 71% Oxazolidinos and 70% Liconsamids. Interestingly, some Flavobacterium, Pseudomonas and Curtobacterium strains showed AMR to >18 different assayed antibiotics. In isolated strains, VF assays also revealed percentages of >40% lecithinase activity, 35% hemolytic activity, 21% pyocyanin production and 5% DNAse activity. A high diversity, AMR and VF were observed in culturable bacteria inhabiting surrounding soils of the Ecology Glacier. Acknowledgements: project ACT210044.

577

How do near-future ocean stressors affect the fatty acid composition of the calcifying benthic Antarctic species?

DR NATALIA SERVETTO^1,2, DR MARLEEN DE TROCH³, DR FREDERIC GAZEAU⁴, DR GASTON ALURRALDE^5,6, DR CARLA DE ARANZAMENDI^1,7, DR MICAELA RUIZ⁸, DR RICARDO SAHADE^1,2

¹Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Ecología Marina, CORDOBA, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA). Ecosistemas Marinos y Polares., CORDOBA, Argentina. ³Marine Biology, Department of Biology, Ghent University, GENT, Belgium. ⁴Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, Villefranche-sur-Mer, NICE, France. ⁵Baltic Marine Environment Protection Commission HELCOM, Helsinki, Finland. ⁶Department of Environmental Science, Stockholm University, HELSINKI, Finland. ⁷Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA). Ecosistemas Marinos y Polares, CORDOBA, Argentina. ⁸Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research, BREMERHAVEN, Germany

Abstract

The twin threats of ocean warming (OW) and acidification (OA) impose significant consequences on lipid metabolism and the composition of fatty acids (FA) in various organisms, especially calcifies. These biochemical components are crucial for the survival and reproduction of widely distributed aquatic invertebrates ubiquitously exposed to fluctuating environmental changes like salinity, temperature (Tº), and carbon dioxide levels. Seeking to obtain more accurate predictions of the effects of multiple stressors on the Antarctic benthic communities, we proposed to work with two of the most abundant calcifying Antarctic species from Potter Cove (the coral Malacobelemnon daytoni and the bivalve Aequiyoldia eightsii). The main aim was to study the effects of OW and OA (alone and in combination), through FA studies in a two-month experiment. Between the results observed here, we can highlight that OA and OW do not have any significant effect on the composition of FA ratios associated with immune function (n-3/n-6) and cell membrane fluidity (PUFA/SFA and MCL) in both species compared with the control. FA composition associated with inflammatory response (PUFAs) was also unaffected by predicted OA and OW (except for a decrease at the 20:5n-3 FA in an extreme Tº condition in the bivalve). The lipid biochemistry in adult specimens of these species appears robust to near-future climate change, but further research is necessary to validate and generalize these findings to other species, life stages, and environmental contexts.

578

An outsider on the Antarctic Peninsula: A new record of the non-native moth Plodia interpunctella (Lepidoptera: Pyralidae)

Dr. Carla Ximena Salinas¹, Dr. Hugo Benítez^2,3,4, Dr. (c) Jordan Hernández^2,3,5, Dr. Tamara Contador^2,3,6, Dr. Sanghee Kim⁷, Dr. Claudia Maturana^2,3, Dr. Lorena Rebolledo¹, Dr. Laura Pérez⁸, Dr. Paulo Camargo⁹, Dr. Vinicius Ferreira¹⁰, Dr. Isabel Lobos^2,4, Dr. Alejandro Piñeiro^2,4, Dr. Peter Convey^11,2,3,12

¹Instituto Antártico Chileno, Punta Arenas, Chile. ²Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems, Santiago, Chile. ³Cape Horn International Center (CHIC), Centro Universitario Cabo de Hornos, Universidad de Magallanes, Puerto Williams, Chile. ⁴Laboratorio de Ecología y Morfometría Evolutiva, Centro de Investigación de Estudios Avanzados del Maule, Universidad Católica del Maule, Talca, Chile. ⁵Programa de Doctorado en Salud Ecosistémica, Centro de Investigación de Estudios Avanzados del Maule, Talca, Chile. ⁶Núcleo Milenio de Salmónidos Invasores (INVASAL), Concepción, Chile. ⁷Division of Life Sciences, Korea Polar Research Institute, Incheon, Chile. ⁸Departamento de Física, FACI, Universidad de Tarapacá, Arica, Chile. ⁹Departamento de Botânica, Universidade de Brasília, Brasilia, Brazil. ¹⁰Agronômica, Laboratório de Diagnóstico Fitossanitário e Consultoria, Porto Alegre, Brazil. ¹¹Department of Zoology, University of Johannesburg, Auckland Park, South Africa. ¹²British Antarctic Survey (BAS), Natural Environment Research Council, Cambridge, United Kingdom

Abstract

We report the first record of the microlepidopteran Plodia interpunctella beyond the South Shetland Islands at the Chilean Yelcho scientific station (64°52′33.1428″ S; 63°35′1.9572″ W), Doumer Island, close to the west coast of the Antarctic Peninsula. It is notable that P. interpunctella, a globally distributed stored product pest species, exhibits a remarkable capacity for prolonged viability within food storage facilities. The dual challenges of food transportation and storage in the context of Antarctica's challenging operational conditions may have facilitated P. interpunctella's initial arrival to the Antarctic region. Non-perishable food items, such as grains, flour and rice, provide practical options for the bulk food transportation and storage required in the long-term operation of Antarctic research stations. The presence of P. interpunctella in Antarctica, even if restricted to synanthropic environments within buildings, is a clear threat to Antarctic biodiversity, not only through being an invasive species itself but also as a potential vector for other non-native species (bacteria, acari, between others.), which could carry diseases to the native species.

579

Voices from the desert: the vision of the high-Andean Atacameño peoples on climate change and the future of water.

Fabricio Morais Rosa¹, Ícaro Oliveira de Miranda¹, Clara Glória Oliveira Baldi², Davi Feital Gjorup¹, Maria Alice Fernandes Correa Mendonça³, Bruno Nery Fernandes Vasconcelos Vasconcelos¹, Carlos Ernesto Gonçalves Reynaud Schaefer¹

¹Núcleo Terrantar - Universidade Federal de Viçosa, Viçosa, Brazil. ²LABGEO - Universidade Federal de Viçosa, Viçosa, Brazil. ³Departamento de Economia Rural - Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

Deserts, like the Atacama, where people can live with minimal water supply, suffer from climate change, significantly impacting local agriculture and communities’ lives. This project studies traditional land uses in irrigated terraces, aiming to amplify the voices of people directly impacted by climate changes in small local communities. It seeks to strengthen understanding of the environmental phenomenon and its repercussions on the Atacameño social fabric, expanding climate change perception from traditional peoples, boosting the search for solutions. By conducting open interviews with residents living in two traditional villages (Ayquina and Camar), in the province of El Loa, the singularities of the natural landscape and the patterns of land use and cultivation in irrigated systems of constructed terraces were observed and described. During these interviews, participants shared facts and personal experiences about climate change throughout their lifetime. Dwindling meltwater and precipitation, in line with the decrease in annual high mountain snow cover, increasing temperature and climate irregularity, were participants common perceptions. Farmers from Camar emphasized the direct influence of these factors on crop development and harvest success, with rising temperatures resulting in earlier and more uncertain cropping cycles. Conversely, in Ayquina, abnormal episodes of intense rain caused severe silting of the Rio Salado and, consequently, the erosion or flooding of the most noble agricultural terraces, making them unusable, and limiting the already scarce arable areas. The project brings an ethnoecological dimension to climate change studies in an Andean high mountain environment, where environmental changes in an extreme desert setting impact people living with minimal water supply. It is hoped that this inventory of perceptions brought to light can bring a new approach to the problem, centered on the voice of traditional peoples, who occupy, in a sustainable and ancestral way, one of the most extreme climatic regions on the planet.

581

Statistical analysis of the radial response of relativistic electron fluxes in the outer radiation belt during disturbed geomagnetic times.

Yulissa Espitia, Dr Victor Pinto, Dr Marina Stepanova

universidad de santiago de chile, santiago, Chile

Abstract

The Earth's magnetosphere, acting as a protective barrier against solar wind, plays a crucial role in preserving the atmosphere and living conditions on our planet. Simultaneously, in the region closest to Earth, its nearly dipolar structure creates the magnetic environment ideal for trapping and energizing ions and electrons, giving rise to the so-called radiation belts, highly energized and variable regions. In this context, understanding the radial response of high-energy (relativistic) electrons in the outer radiation belt during periods of geomagnetic disturbances becomes an essential component in comprehending the dominant physical processes in this interaction between the Sun and Earth. in this work, through a comprehensive statistical analysis, the dynamic processes occurring in the radiation belts were investigated, thereby fostering a deeper understanding of the fundamental space phenomena impacting our atmosphere and terrestrial environment.

To conduct this analysis, a dataset comprising flux enhancement events in geostationary orbit between 2012 and 2018 was used. It has been observed that, generally, the response of the radiation belts during enhancement events is cohesive for L > 4.0 and consistently similar for L > 3.5. Subsequent peak fluxes following enhancement exhibit notable correlation across all L > 4.0, although the magnitude of pre-existing fluxes in the outer belt plays a significant role, rendering the relationship between pre- and post-enhancement fluxes less predictable in the 4.0 < L < 4.5 region. For L < 4.0, fluxes show little correlation with geostationary orbit but also tend to be less variable. Additionally, geomagnetic conditions associated with events causing decreases for lower L values were studied, providing a comprehensive understanding of the evolution of electron fluxes in this context.

588

Stochastic topography inversion of the Denman trough

Dr Mareen Loesing^1,2, A/Prof Dr Alan Aitken^1,2, A/Prof Dr Emma MacKie^3,4, Dr Lu Li², Michael Field^3,4

¹Australian Centre of Excellence for Antarctic Science, The University of Western Australia, Perth, Australia. ²School of Earth Sciences, The University of Western Australia, Perth, Australia. ³Department of Geophysics, Stanford University, Stanford, CA, USA. ⁴Department of Geological Sciences, University of Florida, Gainesville, USA

Abstract

To accurately image the subglacial topography of one of East Antarctica's fastest retreating glaciers, the Denman Glacier, radar data encounters challenges, especially in regions with deep and confined troughs and floating ice. To address these shortcomings, the Australian Denman Terrestrial Campaign incorporated high-resolution ground-based gravity data collection. This serves as a valuable supplement to radar imaging, offering insights into the glacial depth and underlying bedrock geology of the Denman Glacier.
Utilizing a Markov Chain Monte Carlo-based inversion technique, a random Gaussian field is generated with each iteration, perturbing the bed, and ultimately yielding a probability distribution representing potential subglacial topography scenarios. The collected gravity data suggests that the glacier trough may extend to considerable depths, making it susceptible to the marine ice sheet instability phenomenon. These revelations underscore the significance of ground-based data collection in studying sub-glacial topography and contribute valuable knowledge to the broader understanding of Antarctic ice dynamics.

589

Evaluating ice thickness on permanently frozen Antarctic lakes with a combination of Landsat imagery and in situ measurements.

Charles Dougherty¹, Dr. Hilary Dugan¹, Dr. Mark Salvatore², Dr. Peter Doran³

¹University of Wisconsin-Madison, Madison, USA. ²Northern Arizona University, Flagstaff, USA. ³Louisiana State University, Baton Rouge, USA

Abstract

The McMurdo Dry Valleys (MDVs) are the largest unglaciated region in Antarctica and are populated with permanently ice-covered lakes. These ice covers define the available habitat within the water column, providing a shield from atmospheric exchange and wind mixing events, and greatly reducing the amount of available photosynthetically active radiation. As climate change accelerates warming in the MDVs, it is critical to understand how the ice covers will be impacted since they are foundational to the aquatic habitat of this extreme ecosystem. Long-term data collection by the McMurdo Dry Valleys Long-Term Ecological Research program shows that the lake ice covers go through decadal thinning and thickening trends, ranging between 2.5 to 6.5 meters thick. These fluctuations are often thought to be driven by air temperature and changes in albedo due to aeolian sediment deposition. Although the drivers have long been identified, the actual mechanics behind these shifts in thickness are not well understood. Here, we use a combination of Landsat imagery, historical data, and high frequency in situ climate measurements to quantify the drivers regulating ice thickness in this extreme environment. Understanding how the permanent ice covers of MDV lakes function is critical in predicting how and under what conditions the lakes might change in the future as a result of climate change.

590

Enzymatic potential for microplastic degradation in Antarctic soils impacted by penguins: higher abundance in soils close to human settlements.

Alexander Marin^1,2, Claudio Valenzuela^1,2, Lia Ramirez^3,4, Julieta Orlando^1,2

¹Universidad de Chile, Santiago, Chile. ²Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Santiago, Chile. ³Domolif SpA, Antofagasta, Chile. ⁴Universidad Arturo Prat, Iquique, Chile

Abstract

Global plastic production rise leads to increasing microplastic pollution, adversely affecting ecosystems on a global scale. Even in remote regions such as Antarctica, there is evidence of microplastics affecting various organisms within the food web, including penguins. Penguins transfer them into soil through excrement or other waste. Then, microorganisms in penguin colony soils may have adapted to the presence of microplastics by developing strategies to metabolize them. This study aims to evaluate the presence of genes coding enzymes responsible for microplastics’ degradation in soils impacted by penguins and to examine the relationship between the abundance of these genes and the proximity to human settlements. Soil samples (54) were collected from colonies of Pygoscelis penguins across the Antarctic Peninsula and subjected to metagenomic analyses, focusing on genes encoding enzymes that degrade polyethylene terephthalate (PET), polyurethane (PUR), polystyrene (PS), and polyethylene (PE). A specific database was created to detect genes encoding these enzymes within metagenomic reads. A hidden Markov model was constructed for each enzyme, and Spearman's coefficient was utilized to assess the correlation of enzyme abundances across the different sampling sites. Our findings reveal the presence of genes encoding enzymes involved in microplastic degradation in soils impacted by Pygoscelis penguins. Among these, PET hydrolases appear to be the most prevalent, with a maximum abundance of 1.4 hits per million base pair (hits/Mb), followed by alkane hydroxylases responsible for PE degradation (0.9 hits/Mb), polyurethanases targeting PUR (0.5 hits/Mb), and styrene monooxygenases associated with PS degradation (0.3 hits/Mb). On the other hand, we found a slight negative correlation between gene abundance and the distance of sampling sites from human settlements, suggesting an increased abundance closer to settlements. Understanding microbial diversity capable of degrading microplastics and their adaptation to Antarctic environments is crucial to propose future bioremediation strategies.

592

SEA ICE MELTING-RESULTED COLD AND FRESHWATER PULSE IMPACTS ON THE SOUTHERN HEMISPHERE STORM TRACKS

Claudia Parise¹, Kevin Hodges², Luciano Pezzi³, Nelson Ferreira⁴, Camila Carpenedo⁵, Fernanda Vasconcellos⁶, Ana Laura Torres⁷, Michelly Queiroz⁴

¹Federal University of Maranhão - UFMA, São Luís, Brazil. ²University of Reading, Reading, United Kingdom. ³National Institute for Space Research, São Jose dos Campos, Brazil. ⁴National Institute for Space Research, Sao Jose dos Campos, Brazil. ⁵Federal University of Paraná, Curitiba, Brazil. ⁶Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ⁷Federal University of Fluminense, Niteroi, Brazil

Abstract

Historical satellite records from 1979 to 2015 have shown a slight though significant increase in the total Antarctic sea ice (ASI), with the last record high occurring in October 2014. The increasing trend of ASI has appeared physically paradoxical to what might be expected in a warmer global climate. Since 2016, nonetheless, a significant decrease in the ASI has started to occur. On February 20, 2024, the ASI reached its minimum monthly extent (1.99 million km2), tying for the second lowest extent provided by satellite records. Based on ensemble experiments performed with the GFDL/CM2.1 model (10-years), the response of the Southern Hemisphere (SH) storm tracks to a cold, freshwater pulse generated from the melting of ASI extremes imposed in the coupled model was studied, as well the response of transient atmospheric eddies and the South Atlantic tropospheric meridional circulation in the two-timescale climate mechanism previously proposed by authors. The SH storm tracks were investigated using a tracking algorithm. ASI maxima led to enhanced poleward heat flux mainly over the middle and high latitudes. During the first 4-years of simulation, a strengthening of the polar jet and an intensification of the SH storm tracks, a southward shift of the subtropical jet, and an inversion from the positive to negative phase of the Southern Annular Mode are observed. We found that 10-years of coupled simulations were enough time to propagate the climate signal generated from the ASI melting pulse towards the Tropical Atlantic, around 2-years later, through the meridional circulations cells. Nonetheless, the period needed to completely dissipate the disturbance generated by ASI seems to be longer. This study has great relevance for understanding global climate changes in the short term by assessing the sensitivity of South Atlantic circulation to extreme variations in ASI.

593

Ionospheric medium and long-term trends over Antarctic Peninsula

Marayen Canales¹, Manuel Bravo², Ana G.Elias^3,4

¹Universidad de Concepción, Concepción, Chile. ²Universidad Adventista de Chile, Chillán, Chile. ³Universidad Nacional de Tucuman, Tucuman, Argentina. ⁴INFINOA, Tucuman, Argentina

Abstract

The Earth's ionosphere is sensitive to solar and geomagnetic variations, which impact in radio communications and navigation systems. These ionospheric variations are both spatial and temporal, with the latter ranging from seconds to long-term trends. Experimentally, the study of these variations involves measurements from instruments distributed worldwide. The distribution, however, is not even, with a more extensive network of instruments in the Northern than in the Southern Hemisphere. This asymmetry is due in part to the fact that the Southern Hemisphere has less landmass for their installation. The Antarctic Peninsula, a region in high geographic latitudes but mid-magnetic latitudes, is strategic for the scientific instrumental deployment in the Southern Hemisphere. This study evaluates mid-term changes and long-term trends in this region using the critical frequency of the F2 layer (foF2) measured in the ionospheric stations of the Argentine Islands (65°S, 64°W) from 1962 and 1992 and the King George Island (62°S, 59°W) from 1986 to 1991. Also Total Electron Content (TEC) is evaluated to this propose. Mid-term variations are analyzed in relation to global-scale phenomena in lower atmospheric layers, and long-term trends as possible consequences of the well-known greenhouse gases increasing concentration mainly, but also in connection to natural forcings as well.

596

Representing fifty years of biogeographical knowledge for spatially explicit ecological modeling

Assoc. Prof. Charles Lee¹, 2. Alejandra Verde Jirón², Brandon Whitehead³, Fraser Morgan⁴

¹University of Waikato, Hamilton, New Zealand. ²Scientific-a, Brinklaan, Netherlands. ³Manaaki Whenua Landcare Research, Palmerston North, New Zealand. ⁴Manaaki Whenua Landcare Research, Auckland, New Zealand

Abstract

To generate projections of Antarctic biogeographic patterns in a warming climate, spatially explicit ecological models that incorporate biogeographic processes are required. These models, in turn, require spatially and taxonomically consistent representations of extant biogeography that can rationally and consistently express spatial uncertainty, most commonly done using geographic coordinates. However, civilian-use Global Positioning System (GPS) equipment was not widely available until the late 1990s, and the inclusion of GPS coordinates for sampling sites in scientific publications remains inconsistent today. We devised a system for capturing and representing biogeographical information extracted from almost 5,000 scientific publications since the 1970s, which is spatially explicit yet accounts for heterogeneities in how geographical locations were recorded in publications. Critically, this system is capable of defining spatial geometry using location names since only a small minority of the data sources contained GPS coordinates while accounting for the divergent area sizes associated with location names (e.g., Spaulding Pond vs. Taylor Valley). Our system utilizes the Discrete Global Grid System (DGGS), a partitioning of the Earth’s surface into hierarchical cellular grids. Our implementation of DGGS uses hexagons, which allow easy approximation of radii, simplifying analyses and smoothing over gradients. Upon ingestion, biogeographic data are assigned to appropriately sized grid cells based on their interpreted individual spatial uncertainty, and the probabilities of the taxa’s occurrence at various grid cell sizes are calculated; occurrences reported in multiple publications are considered to adjust their probabilities and reduce spatial uncertainties. For ecological modeling, the system outputs biogeographical data as probabilities of occurrence for each taxon across all grid cells at a designated resolution while keeping track of the provenance and original spatial resolution of the data points. Importantly, the utilization of DGGS allows for the capture of sub-cm spatial resolution where needed, future-proofing our system for ultra-high-resolution data sets.

602

Analyzing the Genomic Adaptations of Antarctic Krill to Climate Change: A Machine Learning Approach

Mr Rifaldy Fajar¹, Ms Sahnaz Vivinda Putri², Ms Badde Lela³

¹Computational Biology Laboratory, Yogyakarta State University, Sleman, Indonesia. ²Bioinformatics Research Group, International University Semen Indonesia, Gresik, Indonesia. ³Department of Marine Biology, Udayana University, Denpasar, Indonesia

Abstract

This study investigates how Antarctic krill (Euphausia superba) respond to climate change using machine learning techniques on genomic data. Our aim is to identify genomic adaptations crucial for krill survival in shifting environmental conditions, focusing on markers associated with thermal tolerance, diapause regulation, and responses to food availability. We employed an integrative machine learning framework to analyze the Antarctic Krill Population Genomics dataset, consisting of over 15,000 individual krill genomes across diverse geographic regions and temperature gradients. Our methodology involved thorough data preprocessing to ensure accuracy, followed by the application of unsupervised learning algorithms for pattern recognition to identify clusters of genomic variation associated with environmental factors. Furthermore, we utilized supervised learning models to correlate specific genomic markers with environmental adaptability traits, focusing on thermal tolerance and diapause mechanisms. To track temporal dynamics of genomic adaptations, we employed deep learning architectures and correlated changes with historical climate data, providing valuable insights into Antarctic krill adaptation. Our analysis identified a set of 243 genomic markers strongly associated with thermal tolerance and diapause regulation, exhibiting a 95% confidence in predictive accuracy for krill survival under varied temperature conditions. We discovered a cluster of genes related to lipid metabolism that varied significantly (P<0.05) with historical sea ice concentration changes, suggesting a genomic basis for diapause and feeding strategy adaptations. Longitudinal tracking indicated a rapid genomic shift post-1950, coinciding with accelerated climate change, with an observed genetic drift rate of 0.8% per decade (95% CI: 0.75% - 0.85%). Additionally, machine learning models successfully predicted regional population vulnerabilities, highlighting areas where krill populations may face significant survival challenges in the next 50 years. This study employs machine learning in Antarctic krill genomics, emphasizing their climate change adaptation. Identifying genomic markers informs conservation, emphasizing the integration of genomic data with machine learning to predict climate change effects.

603

Predicting the Future of Antarctic Lichen Diversity Under Climate Change: An AI-Driven Approach

Mr Rifaldy Fajar¹, Ms Sahnaz Vivinda Putri², Ms Elfiany Evy³

¹Computational Biology Laboratory, Yogyakarta State University, Sleman, Indonesia. ²Bioinformatics Research Team, International University Semen Indonesia, Gresik, Indonesia. ³Department of Environmental Science, Hasanuddin University, Makassar, Indonesia

Abstract

Background/Aim: Antarctic lichens, crucial for biodiversity, nutrient cycling, and environmental monitoring, face significant threats from climate change. Predicting their future distribution and diversity in the continent's vast and remote habitats poses a challenge. This study employs artificial intelligence (AI) to model Antarctic lichen responses to climate change, aiming to offer precise forecasts for these vital ecosystems. Methods: We collected over 10,000 records of Antarctic lichen species occurrences from the Global Biodiversity Information Facility, along with environmental and climatic data layers, such as temperature, moisture, and UV radiation levels, from 1990 to 2023. A novel artificial intelligence model was developed, incorporating Convolutional Neural Networks (CNNs) for processing spatial data and Generalized Additive Models (GAMs) to capture the non-linear relationships between the presence of lichens and environmental variables. This hybrid approach facilitated the integration and analysis of complex, high-dimensional datasets. The model was trained to identify patterns and forecast changes in lichen diversity and distribution under various climate change projections (RCP 2.6, 4.5, and 8.5 scenarios). Results: The AI model achieved an overall accuracy of 88% in predicting current distribution patterns, with a precision of 90% for identifying high-diversity hotspots. Under the RCP 8.5 scenario, the model forecasts a significant habitat contraction for 60% of the lichen species studied, with a 40% reduction in suitable habitats across the maritime Antarctic by 2050. It also identifies potential expansion zones in continental Antarctica, where conditions may become more favorable for certain lichen species, projecting a 25% increase in suitable habitats for these taxa. The detailed output includes geospatial distribution maps and species-specific vulnerability indices. Conclusions: This study advances AI in biodiversity conservation, predicting Antarctic lichen changes under climate change, emphasizing the urgent need for conservation and protected areas to safeguard these ecosystems against global climate threats.

607

Investigation of the Interactions Between Sea Ice Algae from the Marginal Ice Zone of Antarctica and Artificial Sea Ice.

Mr James van Niekerk^1,2, Dr Tokoloho Rampai^1,2

¹Department of Chemical Engineering, University of Cape Town, Cape Town, South Africa. ²Marine and Antarctic Research Centre for Innovation and Sustainability, University of Cape Town, Cape Town, South Africa

Abstract

Sea ice algae and sea ice are vital components of Earth's regulatory mechanisms. Understanding the complex interplay between these two elements is essential for predicting ecological shifts and the impacts these shifts have on larger climate systems.

Sea ice algae, incorporated into brine channels during ice formation, undergo changes in temperature and salinity crucial for their development and survival. Temperature impacts growth rates and metabolic activity, while salinity affects nutrient availability and ice structure. Nutrient levels further influence algae growth with brine channel formation providing a localized nutrient source. Irradiance, essential for photosynthesis, varies seasonally and with ice structure, governing algae growth and survival.

Algae's primary survival mechanism in sea ice involves the secretion of extracellular polymeric substances (EPS), consisting of polysaccharides, proteins, and DNA. EPS forms a protective layer around cells, shielding them from external factors. It also plays a crucial role in biofilm development by enhancing cell adhesion to surfaces through physiochemical alterations while, retaining nutrients and water within cells. Current studies and some preliminary results indicate that EPS has an influence on sea ice physical properties, growth dynamics, crystal texture and structure.

This study focuses on laboratory based artificial sea ice experiments in a temperature controlled environment to investigate the impact of EPS on sea ice. Quantitative temperature and salinity measurements are taken to investigate the influence of EPS on the growth dynamics of sea ice, and therefore the physical properties that result. X-ray computer tomography and cross polarisation analyses techniques are utilised to investigate the impact of EPS on ice textures and microstructure.

608

RECoverable Autonomous Sonde system for sampling and observation of the Qilin subglacial lake: conceptual design

Dr Xiaopeng Fan¹, Professor Pavel Talalay^1,2, Professor Youhong Sun^1,2, Dr Da Gong¹, Dr Zhigang Wang¹, Mrs Ting Wang¹, Dr Yazhou Li², Dr Bing Li², Professor Nan Zhang¹, Professor Rusheng Wang¹, Professor Haibin Yu³, Dr Shilin Peng³, Mr Lin Liu¹

¹Jilin University, Changchun, China. ²China University of Geosciences, Beijing, China. ³Hangzhou Dianzi University, Hangzhou, China

Abstract

A large subglacial lake, the Qilin Lake, with an ice depth of over 3000 m, has been discovered in the Princess Elizabeth area of Southeast Antarctica. Satellite altimetry data shows that the hydrological characteristics of Qilin lake are relatively stable, with almost no lake water discharge or filling occurring. Therefore, Qilin Lake is a preferred location for conducting frontier scientific research on life processes in extreme environments, Earth's climate change, and the evolution of the Antarctic ice sheet. To achieve clean sampling and observation of the Qilin Lake, Jilin University proposed a method of combining "Hot water drilling + Recoverable thermal drilling" for clean access into subglacial lake, and received funding support from the Ministry of Science and Technology of China. Based on this drilling principle, a conceptual design of RECoverable Autonomous Sonde system (RECAS-3000) that can be deployed through hot water borehole were completed. This system mainly consists of a surface winch, a relay cable, a relay compartment, and RECAS. The RECAS and relay compartment will be quickly lowered to the bottom of the hot water borehole by surface winch, and then RECAS can be detached from the relay compartment and penetrated into the subgalcial lake independently. All running data of RECAS and relay compartment during drilling will be transmitted to the surface through relay cable. RECAS-3000 system is planned to be used to scientific drilling project of Qilin Lake in 2027.

609

Ice-thickness reconstruction of the Antarctic Peninsula Ice Sheet north of 70°S

Dr Kaian Shahateet¹, Dr Johannes Fürst², Prof. Francisco Navarro¹, Dr Thorsten Seehaus², Prof Matthias Braun²

¹Universidad Politécnica de Madrid, Madrid, Spain. ²Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany

Abstract

The ice-thickness distribution on the Antarctic Peninsula Ice Sheet (APIS) is important for assessing both the present and future responses of the APIS to climate change. In the present work, our aim is to improve the knowledge of APIS geometry by applying a two-step approach to reconstruct its ice thickness. The first step estimates the ice thickness in the study area using two different approaches, namely, the shallow ice approximation (SIA) and the perfect plasticity (PP) approach. The second step then uses the mass conservation equation to improve the ice thickness estimation in fast-flowing regions (> 200 m a⁻¹) with the aim of overcoming the limitations of the first step. Among the latter, the fact that SIA and PP are not appropriate for low-slope areas, such as those near the glacier termini. Using this approach, we calculate a total volume of 27.7 ± 10.1 x 10³ km³ and a total ice discharge of 97.7 ± 15.4 km³ a⁻¹ fot the APIS north of 70ºS. While our results exhibit substantial errors in comparison with glacier-scale measurements (e.g. a normalized mean absolute error of 35% versus independent measurements on the Flask Glacier), our inversion model demonstrates relatively lower errors in comparison with other reconstructions on the analyzed glaciers. Qualitative analysis further reveals the accurate representation of regional features, such as ice caps, ice falls, and valley glaciers. Despite these advances and the improvements through manual adjustment of glacier outlines at rock outcrops and the introduction of a new approach for prescribing the viscosity and driving stress parameters along the margin, further refinement of input data, particularly ice-thickness measurements, remains crucial for enhancing the accuracy of the ice-thickness reconstructions of the APIS.

610

The ATMOS 2.0 Project: Investigating the Antarctic Climate, the Southern Ocean, and their relationship with the Brazilian and South American environments

Luciano Pezzi¹, Marcelo Santini¹, Claudia Parise², Luis Felipe Mendonça³, Pedro Guimarães⁴, Mylene Cabrera¹, Celina Rodrigues¹, Luciana Lima¹, Andre Lanfer¹, Tiffany Mendonça¹, Camila Carpenedo⁵, Fernanda Vasconcellos⁶, Everaldo Souza⁷, Dirceu Herdies¹, Mário Quadro⁸, Jonas Carvalho⁹

¹National Institute for Space Research, Sao Jose dos Campos, Brazil. ²Federal University of Maranhão, Sao Luis, Brazil. ³Federal University of Bahia, Salvador, Brazil. ⁴Federal University of Santa Catarina, Florianópolis, Brazil. ⁵Federal University of Paraná, Curitiba, Brazil. ⁶Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ⁷Federal University of Pará, Belem, Brazil. ⁸Federal Institute of Santa Catarina, Florianópolis, Brazil. ⁹Centro Euro-Mediterraneo sui Cambiamenti Climatici, Lecce, Italy

Abstract

The study of the Antarctic Climate, the Southern Ocean, and their relations with the Brazilian and South American environment (ATMOS 2.0) project is an innovative initiative that aims to contribute to the integrated understanding of dynamic and thermodynamic processes associated with the interaction of sea ice-ocean-atmosphere-waves at micro, meso and large scales in the Atlantic sector of the Southern Ocean, and exchanges of turbulent, heat, momentum and CO2 fluxes at this interface. The scientific community has addressed multidisciplinary studies of the Earth System, to which this proposal is aligned. Therefore, the ATMOS 2.0 team is dedicated to unraveling the relationships between the ocean and atmosphere components of Antarctica and South America climates, their local processes, their variability, and teleconnections. The study is carried out by observing the climate modes (variability) that link Antarctica and the Southern Ocean to Brazil (teleconnections). The coupling between oceanic and atmospheric systems that influence Antarctica and South America and will be studied on a regional scale. On a local scale, campaigns will be carried out to collect in situ atmospheric and oceanic data, seeking to understand the local processes that are relevant and possible relationships with larger (temporal and spatial) scales. Always having as a guideline, deepening knowledge about the climate of Antarctica and its influences on the climate of South America, following the science advocated in the Decennial Plan for Antarctic Science in Brazil (2023-2032). It is expected, through the implementation of this project, to articulate and train a multidisciplinary team capable of advancing our comprehension of the oceanic, atmospheric, and cryosphere variability, their associated processes, and the possible eventual impacts on the climate of South America. A range of techniques will be used, involving in situ data collected in the ocean and atmosphere, coupled Earth System models, and reanalysis datasets.

611

Integrated geological-geophysical picture of Amery-Lambert sector, East Antarctica: insights into crustal anatomy and geological evolution

Dr Devsamridhi Arora¹, Prof Naresh Pant^2,3, Dr Mayuri Pandey⁴, Dr Rashmi Gupta⁴, Dr Aditya Naik⁵

¹University of Allahabad, Prayagraj, India. ²University of Delhi, Delhi, India. ³National Centre for Polar and Ocean Research, Goa, India. ⁴Banaras Hindu University, Varanasi, India. ⁵Indian Institute of Science Education and Research, Mohali, India

Abstract

The Amery-Lambert Sector (ALS), situated in East Antarctica, is subject to debate regarding its geological classification, oscillating between Grenvillian (~1000 Ma) and Pan-African (~500 Ma) orogenic origins. Over time, significant large-scale geological features have been identified in this sector, including the Kuunga suture intersected by the Lambert rift, the magnificent Gamburtsev subglacial Mountains to the south, the Indo-Australo-Antarctic Suture, and a system of sub-glacial canyons and lakes spanning approximately 1100 km connecting southern arm of Lambert rift to the West Ice Shelf. However, a comprehensive understanding of the sector's evolutionary history remains elusive due to the lack of high-resolution sub-ice geological data and its implications for the overlying ice sheet. Multi-institutional initiatives such as ICECAP in geophysics and GeoEAIS in geology have made significant strides in data collection, providing high-resolution geophysical signatures, and exploring previously neglected locations. As part of the GeoEAIS project, field investigations have been conducted in the least-explored nunataks of the ALS and Princess Elizabeth Land. In this study, we present a detailed analysis of the geological, geophysical, and geothermal aspects of the ALS, illuminating significant crustal features and identifying areas ripe for future exploration. Our findings, combined with existing literature, support the involvement of ALS in three supercontinent configurations during the Neoproterozoic Era before the formation of the Lambert Graben during the Permian period. We also discuss hypotheses concerning the region's full tectono-thermal history and underscore the critical importance of the Amery-Lambert sector in understanding interactions between the ice sheet and bedrock.

612

Analysis of chemical and environmental aspects of a snow core from West Antarctica

Master Regina Souza Ferreira^1,2, Doctor Jefferson Cardia Simões^1,3, Master Isaías Ullmann Thoen¹, Master Ronaldo Torma Bernardo¹

¹Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Instituto Superior de Educação Santa Cecília, Santos, Brazil. ³Climate Change Institute, University of Maine, Orono, USA

Abstract

This study examined the chemical content of a shallow snow core (4.95 m), named TT-6, collected during a Brazilian traverse to the West Antarctic Ice Sheet (WAIS) in the austral summer of 2014/2015. The snow core underwent decontamination and sub-sampling procedures at the Climate Change Institute in Orono, Maine, USA. The ionic content and stable isotope ratios (δD and δ¹⁸O) were determined at the Centro Polar e Climático of the Federal University of Rio Grande do Sul (CPC/UFRGS) and the Isotopic Geology Laboratory (LGI/UFRGS). The results were used to date the snow core and reconstruct the climatic conditions of the collection site. TT-6 represents approximately 11 ± 6 months of precipitation, corresponding to an average snow accumulation rate of 0.19 ± 0.02 m per year in water equivalent. By analyzing the values of non-sea-salt sulfate, we identified a reference horizon related to the Puyehue-Cordón volcanic eruption in Chile in 2011. Anions constitute 53.73% of the ionic content, and there is an acidic cationic contribution of 25.62%, coming from H+. We observed that 96.86% of the calcium and 84.50% of the sulfate are of non-marine origin, while 96.38% of Na+ is of marine source. We obtained high peaks in marine aerosols containing Cl^- and Mg²⁺ during the winter. In addition, the results of the global ERA5 model (NOAA) indicated that El Niño events could influence Antarctic temperatures, facilitating the transport of marine aerosols to the continent.

614

PolarGo: An online information platform for the Antarctic community

Professor Songtao Ai, Dr Jiachun An, Professor Yuande Yang, Professor Fei Li, Dr Feng Xiao

Wuhan University, Wuhan, China

Abstract

Digital Earth Contributes to Sustainable Development Goals of the Antarctic Community. A polar spatial-temporal information platform, namely PolarGo, was designed on top of digital earth. This platform is committed to providing public polar product with 3D Earth visualization, integrating polar data from various resources including remote sensing, visualizing real-time polar activities and environmental changes. More than twenty countries' polar footprints are collecting into this platform, including China, France, Russia, UK, US and so on.

PolarGo is also a geospatial application of Web GIS platform, which is open to every user online (PolarGo.cn).

615

Observations of Antarctic Marine Ice Cliff Dynamics

Caroline Needell¹, Catherine Walker², Jeremy Bassis³

¹MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, MA, USA. ²Woods Hole Oceanographic Institution, Woods Hole, MA, USA. ³University of Michigan, Ann Arbor, MI, USA

Abstract

Earth’s ice sheets flow towards the ocean as glaciers and ice streams, and terminate in the ocean either as floating ice shelves or in grounded steep cliffs. Theory and recent process modeling suggest that the strength of ice limits how tall these cliffs can be, and ice cliff collapse may occur when a critical height of ~90 m above the waterline is exceeded, potentially triggering runaway ice retreat in a positive feedback mechanism known as the Marine Ice Cliff Instability (MICI). MICI remains a controversial hypothesis in part because it is difficult to observe and therefore parameterize, adding significant uncertainty to projections of future sea level rise. Although anecdotally, a height-based failure threshold for ice cliffs appears credible, there are limited published observations of ice cliff heights generally, leaving significant gaps in community understanding of MICI. This project aims to test the theory of a cliff stability limit against a large observational inventory of ice cliffs in diverse glaciological and environmental settings. Here, we present preliminary results from a continent-wide, multidecadal remote sensing survey of ice cliffs around Antarctica’s margins. We will highlight general trends of cliff height and morphology using the data collected thus far, which includes over 6000 individual cliffs identified using ICESat-2 laser altimetry. Additionally, we will focus on case studies of tall (>100 m) extant ice cliffs that highlight the potential for mitigating factors, such as mélange and sidewall buttressing, that may prevent or arrest dramatic MICI-style front retreat.

616

Evolution of winter and summer marine heat waves in Antarctica and its surroundings since 1981

Alvaro Gonzalez-Reyes^1,2, Camilo Marquez¹, Andrea Piñones^3,2, Paula Amador-Veliz³, Octavio Mercado-Peña³, Roxanna Ayllon³, Martin Jacques-Coper^4,5, José Garces-Vargas^3,2

¹Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, Chile. ²Centro FONDAP de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes, Universidad Austral de Chile, Valdivia, Chile. ³Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile, Valdivia, Chile. ⁴Departamento de Geofísica, Universidad de Concepción, Concepcion, Chile. ⁵Center for Oceanographic Research COPAS-COASTAL, Universidad de Concepción, Concepcion, Chile

Abstract

Marine heat waves (MHWs; events of at least 5 consecutive days that exhibit sea surface temperature, SST, above a threshold corresponding to each location) record changes in frequency and intensity in various regions of the world. Their impacts can be severe since they generate alterations in the biodiversity and dynamics of the oceans. In the high latitudes of the southern hemisphere, MHWs have been reported during the austral summer (November to March, NM) in different locations (among others, the Tasman Sea). However, the MHWs during the autumn to spring months (May to October, MO) and also in summer still need to be better understood, particularly in Antarctica and its surroundings. We used daily SST data based on the ERA5 reanalysis to evaluate decadal-scale trends of MHWs during 1981-2022 for MO and 1981-2023 for NM. The 90th (P90), 95th (P95), and 99th (P99) percentiles have been defined as SST intensity thresholds, calculated from the period 1981-2010. MHWs were evaluated using different durations, from 5 to 60 consecutive days. Our results indicate, for MHWs defined from the P90 and P95 percentiles during the MO, when using periods of 5 to 10 days, an increase of up to 1 consecutive MHW event per decade in the Amundsen-Bellinghausen Sea (AB ) and north of the Antarctic Peninsula. Similar results in trends are also found in NM using the three percentiles, which accounts for a similar increase in MHWs observed in the AB Sea, Ross Sea, and Davis Sea.

624

An AIoT platform for long-term and near real-time monitoring of remote environments and micro-climates in Antarctica

Dr Johan Barthelemy^1,2, Dr Krystal Randall^2,3, Cameron Angus², Douglas Henness², Dr Umair Iqbal²

¹NVIDIA, Santa Clara, USA. ²Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, Australia. ³School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia

Abstract

Mosses, the dominant vegetation in Antarctica, play a key role in biogeochemical cycling and offer shelter and habitat for microorganisms and invertebrates. Over recent decades, East Antarctic mosses have undergone community composition changes and a decline in health, however, the drivers of change are poorly understood due to the difficulties of collecting long-term empirical data at scales relevant for mosses. Mosses generate leaf-level climates that differ significantly from ambient conditions, making weather station data unsuitable for monitoring change in these communities. Moreover, building continuous remote monitoring solutions for Antarctica is not easy because of the lack of power and network connectivity, and extreme cold conditions impacting battery life.

To overcome these difficulties, a smart, autonomous, long-range and long-term monitoring platform for remote terrestrial environments in Antarctica is being developed. This Artificial Intelligence of Things (AIoT) platform collects environmental data, processes it in-situ, and sends it back to Australia in near real-time, allowing for year-round global access. For monitoring mosses, the AIoT platform is configured to measure surface, soil, and boundary layer climates, and is equipped with imagery and audio. AI and edge computing technologies (leveraging the NVIDIA Jetson platform) for in-situ processing to transmit only relevant data thus saving network bandwidth, along with the LoRaWAN long-range protocol, allows efficient, low power, long-range wireless data transmission capabilities. This will be illustrated with a live demonstration showcasing the actual prototype.

Addressing many challenges with long-term empirical data collection, and with customisable sensor configurations, this platform aims to enable new research capabilities in Antarctica. The first prototype was successfully tested at the Australian Casey Research Station during the 2022-2023 summer season. The second prototype is under development with a focus on long-term deployment, enabling continuous long-term monitoring of remote terrestrial environments, which will facilitate conservation planning of Antarctica's fragile ecosystems.

625

The effect of High Bandwidth Satellite Communications on Telemedicine in Antarctica – Point-of-View Augmented Reality in the field?

Dr Matthew Warner, Dr Jonathon Lowe

British Antarctic Survey Medical Unit, Plymouth, United Kingdom

Abstract

Access to telemedicine in Antarctica has been historically limited by low bandwidth technologies working at the extremes of global satellite coverage. This has, in effect, limited communications to short text-only transmissions in the field. Larger fixed bases have benefitted from permanent satellite dishes allowing reasonable quality voice communication, emails and smaller-sized clinical pictures. Within the last few years this has progressed to lower-resolution video calling with variable quality and availability. This latter development has allowed senior and expert medical support to provide an increased level of support to patients who would otherwise not receive it.

There has very recently been a step change in satellite coverage of Antarctica, with high bandwidth coverage of large areas of the continent. This is now allowing high-resolution video calling with low latency in areas previously unreachable by technological support.

It is important that medicine consider how best to utilise the capability that this tool now offers in the care of patients in the remote setting. It is now possible for senior and expert clinicians to be able to have high-resolution experience of the clinical scenario and to be able to deliver real-time expert advice and guidance to non-experts and possibly non-medical persons who are needing to care for ill and injured patients both on bases but also in extreme deep-field situations where previously there would have been extremely limited or no medical input.

Utilising this technology allows the remote expert to provide significant and high-fidelity support, both emotionally and practically helpful for those providing care at scene as well as directly beneficial for the patient.

The British Antarctic Survey Medical Unit is currently working on the development of augmented reality utilising glasses linked to the satellite communications system for clinical care as well as in pre-deployment training as a high-level use of this technology.

626

High pedodiversity of coastal soils from Maritime Antarctica: a case study at Rip Point, Nelson Island.

Graduation student Anifo Ibraimo¹, Dr. Daniela Schmitz¹, Doctoral student Heitor Palma¹, Dr. Rafael Siqueira¹, Dr. Jônatas Silva¹, Dr. Carlos Schaefer¹, Dr. Márcio Francelino¹, Dr. Guilherme Corrêa²

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal de Uberlândia, Uberlândia, Brazil

Abstract

The soils of Maritime Antarctica possess a strong contrast with soils from other, drier Antarctic climate zones, and are among the most pedodiverse, due to significant variations in soil-forming factors, in addition to the fact that pedological processes in this region occur more intensely due to greater precipitation, solar radiation and temperature.. Rip Point, located on Nelson Island, in the South Shetland Archipelago, is such an ice-free area with soils representative of this pedodiversity. The objective of this work was to characterize the soil forming processes and landscape of Rip Point soils. Ten soil profiles were described and collected. The chemical and physical attributes analyzed were (available P, SB, pH in H₂O, H+Al, Al³⁺, soil organic matter content (SOM), as well as the granulometric analysis). The data obtained were interpreted using descriptive statistics and principal component analysis (PCA). PCA explained 68.7% of the variation in soil physical and chemical characteristics. Profile 6 (RP6) presented a high P content, due to the biogenic contributions of Petrel nests. RP7, on the other hand, presented a high concentration of SOM, exchangeable Al, high potential acidity, more acidic pH (5.2) and low SB, with low biogenic input. The Al is associated with SOM stability, and this soil is found in elevated area, with a longer exposure time and degree of weathering and leaching. The RP1 and RP2 profiles, near the coastal zone, presented a typical high Na content and a predominance of the sand fraction, in uplifted marine terrace environments. The remarkable pedodiversity of Maritime Antarctica, in an area as small as Rip Point, is a consequence of varying factors such as: (i) exposure time, and (ii) nature of the rock; (iii) biogenic inputs; (iv) influence of marine deposition and (v) landscape stability, with great soil differentiation at minute scale.

627

Highly Pathogenic Avian Influenza and the Antarctic Human Interface

Dr Matthew Warner, Dr Jonathon Lowe

British Antarctic Survey, Plymouth, United Kingdom

Abstract

Sadly this 23/24 season has seen the arrival of Highly Pathogenic Avian Influenza (HPAI) into the Antarctic Treaty area, with Bird Island having the first confirmed case in October 2023, and recently south of 60 degrees at Primavera Station. There has also been evidence of unusual mortality within both Elephant and Fur Seal populations, with early testing positive for HPAI within these mammal populations.

HPAI is considered to be a significant risk to the Antarctic wildlife population and thus also potentially the human population studying and working alongside it.

Historically there has not been sustained spread within mammalian (including human) populations, but mortality is very high for those affected.

People working in close proximity to avian and mammalian populations within the Antarctic Treaty area are at the interface of this virus and thus potentially exposed to it. Early indications are that viral expression within seal populations is mainly within brain tissue, and that oro-faecal expression is often low. Although this provides a challenge in the safe obtaining of samples for testing, this lends a degree of reassurance to people in this space. Initial limited evidence shows no mutation suggestive of expected increased transmissibility in humans, and responsiveness to antiviral agents is expected. Additionally, the high airflow environment generally found suggests that viral loading and exposure would be expected to be lower than people working with indoor avian populations.

The use of best practices for Personal Protective Equipment (PPE) is essential to reduce transmission and potential mixing of human and animal influenza viruses. On-site monitoring and testing (environmental, animal and human) needs consideration. Within the human population, careful consideration needs to be employed as to the appropriate interpretation of results. Supply of antiviral medications is important alongside robust planning and oversight.

628

The role of topography in the dispersion of salt (exchangeable sodium) in the soils of the polar semi-desert of Antarctica.

Daniel Nunes Krum¹, Fábio Soares de Oliveira², Carlos Ernesto Gonçalves Reynaud Schaefer¹, Marcos Paulo Evangelista Tomaz¹, Heitor Paiva Palma¹, Ana Carolina Paula do Amaral¹, Roberto Ferreira Machado Michel³, Pedro Henrique Araújo Almeida¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ³Universidade Estadual de Santa Cruz, Ilhéus, Brazil

Abstract

In the western part of the Antarctic Peninsula, a polar semi-desert climate prevails, characterized by minimal liquid precipitation compared to Maritime Antarctica. This area features emerged sections of marine platforms consisting of Cretaceous to Oligocene sediments, historically saturated with salts even during marine conditions. Currently, these salts accumulate, creating saline soils that impact snow accumulation. The study aims to examine how relief affects salt concentration and dispersion in soils, focusing on exchangeable sodium (Na). Soils from the Lopez de Bertodano Formation, situated in the southwest of Marambio Island (Seymour), were investigated. The stratigraphic layers form typical cuesta reliefs with a low dip angle. Eight profiles were analyzed to assess if topographic units influence sodium concentration between horizons and across different slope positions. Results reveal that the deepest horizons (Cf and F) exhibit the highest accumulation of exchangeable Na, suggesting salt migration during thawing cycles, predominantly accumulating in the transition zone between the active layer and permafrost. An anomaly was observed in soils at the base of the reverse slope, where greater Na accumulation occurred in the upper part of the profile. It is hypothesized that in this setting, a migration of exchangeable Na during summer transports sodium to the base of the slope. This behavior was not observed on the cuesta front. All profiles showed elevated Na content in the transition zone, with those at the base of the slope displaying the lowest values, indicating vertical accumulation predominates in front profiles. Erosion in the area promotes the physical accumulation of salt in cataclinal channels, indicating salt concentration through sediment accumulation. The study emphasizes the complex interaction of factors, including relief and chemical and physical movement dynamics, in sodium dispersion in Lopez de Bertodano Formation soils.

629

Are there organo-mineral A horizons in the polar semi-desert of Antarctica?

Ana Carolina Paula do Amaral¹, Daniel Nunes Krum¹, Fábio Soares de Oliveira², Carlos Ernesto Gonçalves Reynaud Schaefer¹, Marcos Paulo Evangelista Tomaz¹, Roberto Ferreira Machado Michel³, Heitor Paiva Palma¹, Pedro Henrique Araújo Almeida¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ³Universidade Estadual de Santa Cruz, Ilhéus, Brazil

Abstract

Surface A horizons, characterized by mineral composition, dark coloration, and distinct structures indicative of higher organic matter content, are identified using total organic carbon (TOC) as a chemical marker. Decomposition of vegetation and fauna within the soil contributes to organic carbon accumulation. In Antarctica's polar semi-desert regions, primarily on the eastern Antarctic Peninsula, surface vegetation is sparse, with fauna limited to coastal areas and occasional penguin rookeries. We conducted a study assessing TOC content in 53 soil profiles within the Lopez de Bertodano Formation on Marambio Island (Seymour) to ascertain the presence of A horizons in Antarctica's semi-polar deserts. Analysis included superficial (A horizon), underlying (B or C), and deepest (C or F) horizons, quantifying TOC using the Walkley-Black method. Results indicate surface horizons average 15 cm in thickness, with organic carbon content ranging between 0 and 0.72 dag/kg and an average of 0.33 dag/kg. Subsequent horizons exhibit similar to slightly higher TOC levels, averaging 0.35 dag/kg. Deeper horizons show higher TOC enrichment, averaging 0.45 dag/kg, with no evident podzolization. This trend is consistent across varied soil textures, suggesting carbon originates from parent materials known for high fossil content and low diagenesis. Pedogenesis in Antarctica's polar-desert environments occurs without the formation of A-class organo-mineral horizons, resulting in profiles with unconventional morphology.

630

Unusual Soils on intrusive basalts hosted in marine sediments at the semiarid Marambio Island (Seymour), Antarctica.

Lucas Hestevan Malta Alfredo¹, Daniel Nunes Krum¹, Fábio Soares de Oliveira², Carlos Ernesto Gonçalves Reynaud Schaefer¹, Heitor Paiva Palma¹, Marcos Paulo Evangelista Tomaz¹, Ana Carolina Paula do Amaral¹, Roberto Ferreira Machado Michel³, Pedro Henrique Araújo Almeida¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ³Universidade Estadual de Santa Cruz, Ilhéus, Brazil

Abstract

The Weddell sea sector of Antarctica is located in the northwest part of the Antarctic Peninsula, forming a group of islands that represents a key area for environmental studies due to its climatic transition and geological diversity. Marambio Island (Seymour) stands out within this region, with soil studies only focused on the marine sediments, particularly in the southeast sector. We describe some unusual soils formed on intrusive igneous (mafic) rocks within the sedimentary layers of the López de Bertodano (Cretaceous) and Sobral (Pliocene) Formations. Eight soils on these basaltic dikes, dated to the Pliocene and extending in a Northeast-Southwest direction, were collected and subject to routine chemical analyses, four from each formation. We evaluated whether soil attributes were strictly associated with the underlying basalts, or else influenced by the surrounding sedimentary rocks. Results indicate higher mean pH values in water for soils from the Sobral Formation (6.5) compared to the López de Bertodano Formation (5). In contrast, the mean values of Electrical Conductivity (EC), Exchangeable Sodium (Na), and Base Sum (SB) were higher in the López de Bertodano Formation (13.5 dS/m, 3472 mg/dm³, and 47.1 cmolc/dm³, respectively) than in the Sobral Formation (10 dS/m, 498 mg/dm³, and 28.9 cmolc/dm³, respectively). These discrepancies suggest that the surrounding sedimentar rocks do influence the basalt soil chemical attributes, emphasizing the mixing of soil materials, despite the compositional uniformity of the dike. The likely process is the wind-blown sedimentary mixing, a key factor shaping semiarid Marambio Island's landscape.

631

Modelling bryophytes' distributions in Antarctica: unveiling the influence of water availability, sampling bias, and spatially complex dynamics

Gabrielle Koerich¹, Hao Ran Lai¹, Grant Duffy², Eva Nielsen¹, Jonathan Tonkin¹

¹University of Canterbury, Christchurch, New Zealand. ²University of Otago, Dunedin, New Zealand

Abstract

Understanding and predicting the spatial occurrence of species is a crucial aspect of ecology and biogeography, and essential for conservation. The most used method to assess species distributions are Species Distribution Models (SDMs), which rely on the assumption that the current species range is directly linked, and in equilibrium, with environmental conditions. However, species distributions are a combination of abiotic, biotic, and spatially complex dynamics. Our observations of populations are also often incomplete and commonly restricted to presence-only data. In Antarctica, this sampling issue is particularly pronounced, and thus understanding and forecasting the range dynamics of key taxa, such as bryophytes, requires a modelling framework capable of dealing with such challenges. Here, we developed log-Gaussian Cox process models of bryophytes’ across the entire Antarctic continent to (1) assess whether broad-scale bryophytes distributions are driven by water availability, as widely hypothesized; (2) map and forecast their distributions and identify under sampled regions; and (3) determine if there’s a spatial dependency between “patches” of bryophytes, which may be related to their limited dispersal in Antarctica. Results show that the main driver of bryophytes distributions in Antarctica is indeed related to areas where water tends to accumulate. Maximum temperature was the second most important predictor, signalling the importance of elevated temperatures for bryophytes’ restricted metabolism in this extreme environment. The covariate related to human activity showed a high level of sampling bias, and by accounting for this covariate in predictions, we detected habitat suitability for bryophytes in two under-sampled mountain ranges. Finally, the inclusion of a Gaussian random field to account for spatial autocorrelation increased model performance, indicating a spatial dependency between the presence of mosses. Our study demonstrates that a spatially structured modelling framework can provide robust results and allow for valuable forecasts of biodiversity change in the continent.

632

Age and features of Falkland Peatlands

Sandro Sérgio Tavares Cicarini¹, Antônio Carlos Ribeiro Filho¹, Lucas Hestevan Malta Alfredo¹, Fernandes Antônio Costa Pereira¹, Eduardo Osório Senra^2,1, Carlos Ernesto Gonçalves Reynaud Schaefer¹, Marcio Rocha Francelino¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²Universidade Federal de Uberlândia, Monte Carmelo, Brazil

Abstract

The study of the genesis of peatlands, deep layers of accumulated organic carbono, brings insights into past climates and the resilience of these ecosystems in the face of climate change, with global repercussions. The largest area of deep peatlands in the South Atlantic is located in the Falkland Islands, and represent a key proxy for understanding climate changes in this part of Subantartica. We studied and determined the organic carbon (OC) contents and age of peats in three representative East Falkland peatlands (Pt1, Pt2 and Pt3), aiming to understand the OC accumulation process. Soil samples were collected to determine the OC concentration, density (Ds), humic acid fractions and radiocarbon dating. The carbon accumulation rate (TAC) was calculated based on thickness, Ds, OC content and age. The OC contents varied from 9.87 to 41.58 dag kg-1, while the Ds varied between 0.16 and 0.36 g cm-3. The highest TAC, 11.21 g m-2 year-1, was found in the 1.7 m thick Pt1, with a calibrated age of 10,800 years B.P. The lowest TAC, 2.53 g m-2 year-1, was found in Pt3, whose thickness was 0.6 m, dating from 6,330 years B.P. The only Late Pleistocene peat was Pt2, the oldest recorded in this study, dating back 11,880, and measuring 1.6 m thick, with a TAC of 8.7 g m-2 year-1. These peatlands have high Ds and OC contentes compared with the global average, and low overall TAC, due to limited primary production in the Falklands. Their age of formation predates most peatlands from elsewhere in South Atlantic and elsewhere, and concentrated in the Late Pleistocene/Early Holocene.

633

Testing extremes: how sea-ice has changed phytoplankton biomass in the Ross Sea polynyas using a 1-D model.

Dr Angela Bahamondes¹, Dr Helen Macdonald², Dr Holly Winton³, Dr Graham Rickard²

¹CEAZA, Coquimbo, Chile. ²NIWA, Wellington, New Zealand. ³Victoria University of Wellington, Wellington, New Zealand

Abstract

About 40% of the total primary production of the Antarctic Ocean occurs in the Ross Sea, a high-latitude, nutrient-rich continental shelf system. This region exhibits substantial variability in physical forcing, sea ice, and biological processes at different regional and time scales, with coastal polynyas playing an important role. Observations in the Ross Sea have shown a 30% reduction in polynya ice production between the 1990s and 2000s, and extensive sea ice loss in 2016 and 2022. Plankton communities in this region are driven, in part, by sea ice dynamics and these associated polynyas. To understand how future climate change might affect these sea ice-phytoplankton dynamics, it is crucial to investigate the natural baseline over the past two centuries. Here, a one-dimensional coupled physical-biological model is used to assess the effect of sea ice concentration on primary production in the Terra Nova Bay, McMurdo Sound and Ross Sea polynyas. Together with model sensitivity experiments, ice core observations and satellite data, we aim to understand how the different phytoplankton communities have responded to seasonal and inter-annual changes over the past 200 years. Here we present modelling results that show the response of chlorophyll-a (chl-a) to historical and centennial sea ice extremes in the Ross Sea using sea ice constraints from satellite and ice core data, and validate the model output with chl-a satellite observations. We outline our plans to model the sensitivity of the two dominant taxa in the Ross Sea, diatoms and P. antarctica, to changing sea ice and compare them with novel ice core proxies for phytoplankton composition.

634

Soils under the influence of Giant Petrels in Maritime Antarctica.

Viviane Koch¹, Guilherme Corrêa¹, Márcio Francelino², Carlos Schaefer², Danilo Camêlo³, Gabriel Rosa², Eduardo Senra⁴

¹Federal University of Uberlândia, Uberlândia, Brazil. ²Federal University of Viçosa, Viçosa, Brazil. ³Federal University of Espírito Santo, Alegre, Brazil. ⁴Federal University of Uberlândia, Monte Carmelo, Brazil

Abstract

The occurrence of soils in the Antarctic region is limited to ice-free areas, which only cover about 0.35% of the total area of the Antarctic continent. However, various processes contribute to soil formation in this region. One such process is ornithogenesis, which, although often associated with the activity of penguins, also involves other birds, such as petrels, whose impact remains under-researched. The aim of this study was to analyze the influence of petrel (Macronectes giganteus) nesting on the soil properties of Greenwich Island, Maritime Antarctica. For this purpose, 20 surface soil samples (0 - 10 cm) were collected in four areas currently occupied by petrel nests and 20 samples in another four areas in the same landscape position but without currently active nests, totaling 40 samples. Physical, chemical, and statistical analyses were conducted. N-total, P, and C-org are the main explanatory variables for the group created by the Principal Component Analysis, which includes soil samples influenced by current nesting. Soils without this influence formed the second group, showing less acidic pH, and higher levels of Ca and Mg. High levels of P were also found in the soils of the second group, since the presence of this element, due to its low mobility in the soil, indicates that even if there is no evidence of current ornithogenic activity, there was nesting influence in the past, contributing to the process of biogenic P accumulation in the soil. Support: CNPq.

638

Food for thought: How changing sea ice conditions influence microalgae communities.

Ms Jacqui Stuart^1,2, Dr Natalie Robinson³, Dr. Craig Stewart³, Dr. Kirsty Smith¹, Dr. John Pearman¹, Dr. Svenja Halfter³, Prof Ken Ryan²

¹Cawthron Institute, Nelson, New Zealand. ²Victoria University of Wellington, Wellington, New Zealand. ³NIWA, Wellington, New Zealand

Abstract

Changes in community composition and biomass of microalgae are being observed in many aquatic ecosystems due to a changing climate. In 2022, a series of southerly storms in McMurdo Sound caused almost all the landfast sea ice in this region to form in late-August as opposed to late-March. These unusual conditions created congelation sea ice of normal thickness (~2m) as well as newer thin ice (~1m). This provided a unique opportunity to compare Antarctic eukaryotic microalgal community (EMC) composition, diversity, and biomass in sea ice under current and possible future conditions. There was substantial sub-ice platelet layer (SIPL) underneath both types of ice, with 2-3 m under normal ice and 0.5-1 m in newer ice. Sea ice core samples and SIPL cores were collected using a coring drill and a novel platelet layer sampling system that preserves the platelet ice structure. The EMCs were measured using chlorophyll-a, cell concentrations, and high-throughput sequencing metabarcoding. Analysis of normal ice showed highest biomass at the congelation ice/SIPL interface. Peak biomass under thinner ice was in the platelet layer approximately 0.25 m below the congelation ice/SIPL interface. Total integrated biomass in the entire ice/SIPL column was highest in thin ice. There were differences in dominant microalgal species within new and normal congelation and SIPL ice environments and significant differences between congelation ice and SIPL microalgal communities. Polar centric diatoms were prevalent in thick SIPL environments while pennate diatoms dominated were in thin ice of both congelation and SIPL environments. With ongoing climate change, it is anticipated that the timing of sea ice formation will shift later in the season resulting in thinner ice. This will have an impact on ice associated EMC biomass, community composition, and diversity. These changes will influence all organisms that are reliant on these essential primary producers.

641

Analysis of the floristic composition of mosses from Elephant Island (Antarctica) in XX and XXI centuries

CAMELO, A.S. Alan Camelo, CÂMARA, P.E.A.S Paulo Câmara

Universidade de Brasília, Brasília, Brazil

Abstract

Elephant Island (61°08′S 55°07′W), Antarctica, is an island located in the South Shetland Islands archipelago, 245 km away from the Antarctic peninsula. There are several species of mosses on this island, making the region a point of interest for studies of Antarctic flora and effects of climate change on it, since these effects are perceived more intensely in the maritime antarctic region. The region's local flora was only known from a few collections scattered along the 20th century, the majority in the second half of the century and, before the visits of our group, the last collections date from the nineties. More recently, our group visited the island from 2014 to 2016 and carried out collections again on the island. This work consisted of surveying the different collections that occurred on Elephant Island throughout the decades of the 20th and 21st centuries, accessed through searches in the GBIF and SpeciesLink databases, as well as literature review, identification of the material collected in the last decade that was in the herbarium of the University of Brasília (UB), comparison of the locations and periods of the island using Venn diagrams and, lastly, production of an identification key for mosses from Elephant Island. The study points to the existence of 50 species of mosses, distributed in 14 families, in Elephant Island and an inequality in collections between locations on the island, maybe due to geographical complications which makes access to some regions more difficult. The study then draws attention to the need to carry out more expeditions and collections in other locations on the island, in order to create a more reliable floristic profile in order to support future research with more complete data and then, more precisely monitor the effects of climate change in the flora of Antarctica.

643

Permafrost Dynamics in James Ross Soils: Characterization of Occurrence Environments.

Graduation student Marcos Paulo¹, Doctoral student Heitor Palma¹, Doctoral student Daniel Krum¹, Graduation student Icaro Miranda¹, Graduation student Mariana Cassini¹, Dr Fernando Vilela², Dr Cláudio Eduardo³, Dr Marcio Francelino¹, Dr Carlos Schaefer¹

¹Federal University of Viçosa, Viçosa, Brazil. ²Uviversity of São Paulo, São Paulo, Brazil. ³Federal University of Ouro Preto, Ouro Preto, Brazil

Abstract

The study of permafrost is of utmost importance for predicting climate change. Literature points to a continuous permafrost area on James Ross Island; however, it lacks in-depth studies. The aim of this work was to identify indicators of permafrost in soil profiles located on James Ross Island, Antarctica, and to characterize the environment of its occurrence. Fifteen soil profiles near the Johann Gregor Mendel station and another 18 in Santa Martha Bay were described. Where the frozen layer was identified, the temperature of the horizon in direct contact was measured. Considering all the profiles described, only seven, located in Santa Martha Cove, exhibited the frozen lower layer. Additionally, in Santa Martha, the remaining profiles either had lithic contact at shallow depths or had reached the water table, making it difficult to identify the frozen layer. Six profiles that showed a frozen layer were under sedimentary material, where the soils were deeper, ranging from a maximum of 0.8 m to a minimum of 0.30 m. The maximum and minimum temperatures of the horizon in contact with the frozen layer were 5.3°C and 0.1°C, respectively. Another profile exhibiting permafrost was originated from volcanic ash deposition, resembling sedimentary soils but located at a higher elevation. On the other hand, profiles described near the station did not show a frozen horizon and were similar to those in Santa Martha Cove. One hypothesis for the absence of permafrost is a higher salt concentration in this region of the island, which reduces the soil's freezing point. It is concluded that James Ross no longer appears to be an area with continuous permafrost.

Keywords: Antarctica; environment; soil formation.

644

Open-source software for gravity inversions: a new algorithm tailored to modelling sub-ice shelf bathymetry and its uncertainty

Dr Matthew Tankersley¹, Dr Huw Horgan^2,3, Dr Fabio Caratori-Tontini⁴

¹Unaffiliated, Glenwood Springs, USA. ²ETH, Zurich, Switzerland. ³Victoria University of Wellington, Wellington, New Zealand. ⁴University of Genoa, Genoa, Italy

Abstract

Accurate models of seafloor topography beneath Antarctica's floating ice shelves are vital to constraining future sea level rise. Additionally, understanding the spatial variability of the uncertainty is needed to interpret and use these bathymetry products in subsequent modelling efforts (i.e. ocean circulation modelling). The extensive, remote, and in-accessible nature of sub-ice shelf environments limits the techniques available for mapping bathymetry. The method of inverting airborne gravity data to model bathymetry has emerged as a predominant technique. Since there are limited available software options, the majority of gravity-inverted bathymetry models have been performed with proprietary geophysical software, presenting two main issues. Firstly, this limits the accessibility and reproducibility of these studies, and secondly, these types of software can be difficult to alter to the unique challenges of bathymetry modelling.

Here, we present an open-source Python package (Invert4Geom) specifically designed to invert gravity for sub-ice shelf bathymetry. The software provides efficient, robust, and clearly documented methods for gravity reductions, regional field removal, and incorporating and adhering to seismic constraints. Additionally, we provide a stochastic approach to assessing the spatially variable uncertainty of the bathymetry. We hope this software will both open this field of research to those who can't access the proprietary software, and provide a more suitable tool for performing this specific type of gravity inversion.

646

Assessing the vulnerability of Nacella species to Climate Change: a study in the sub-Antarctic and Antarctic regions

Dr Paola Reyna^1,2, Biol Santiago Castillo³, Dr Camila Neder^1,2, Dr Maria Carla de Aranzamendi^1,2

¹Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina. ³Laboratorio de Ecología Evolutiva y Biología Floral, Instituto Multidisciplinario de Biología Vegetal (Universidad Nacional de Córdoba - CONICET), Cordoba, Argentina

Abstract

Southern South America and the Southern Ocean are undergoing environmental transformations due to anthropogenic pressures that impose challenges to marine species. As temperature rises, template-cold water invertebrate species such as Nacella spp. (Mollusca, Patellogastropoda), will be more vulnerable and experience a shrink in its distribution range as temperatures increase southward. To understand the future of this vulnerable group of gastropods, the potential impact of future climate change on the distribution ranges of six species within the genus Nacella was studied using ensemble ecological niche models (ENMs) and representative concentration pathway 8.5 scenarios for the years 2050 and 2100. The results indicate that all the species studied will undergo a species-specific shift in their distribution in response to the projected changes in climate with a decline in habitat suitability. The species will lose suitable areas mainly in the northern edge of their current distribution. Our study suggests that N. magellanica, N. clypeater, and N. concinna appear to exhibit vulnerability, albeit with potentially lesser impact. Nacella magellanica is the limpet that shows the least distribution change. Nacella clypeater and N. concinna, will move southward, while the Antarctic species will expand to other Antarctic areas. The most significant impact is expected for N. deaurata, N. flammea, and N. mytilina, currently distributed across the southern tip of South America. With restricted geographical ranges, these three species face increased vulnerability due to limited migration potential and habitat loss. This comprehensive analysis offers invaluable insights into how Nacella species might confront the challenges posed by the anticipated anthropogenic changes in climate and set the basis for potential responses of phylogenetic associated species. Emphasis on specific species' vulnerabilities and the differential impacts on their distribution enhances our understanding of the potential consequences of climate change in the Antarctic and sub-Antarctic regions.

647

Delving the knowledge on biodiversity and biogeographic connections of the subantarctic MPA Namuncurá/Burdwood Bank: the case of ascidians, diverse and frequent animals of macrobenthic communities

Dr Anabela Taverna^1,2, Dr Maria Carla de Aranzamendi^3,2, Tec Luciana Plum^1,2, Dr Tamara Maggioni^1,2,4, Dr Soledad Acosta², Dr Camila Neder^1,2, Dr Marcos Tatián^1,2

¹Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina. ²Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina. ³Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cordoba, Argentina. ⁴Fundación Ambiente Argentino, Córdoba, Argentina

Abstract

The plateau of the Namuncurá/Burdwood Bank Marine Protected Area (NMPA/BB) -located in the Scotia Arc region, southeastern of Tierra del Fuego, Argentina- is isolated by deep waters, suggesting a particular importance in terms of endemic species of benthic organisms. With predominance of rocky bottoms and coarse biogenic sand, the NMPA/BB sustains a high biodiversity that requires protection, with the presence of vulnerable structure-forming species such as ascidians (Chordata, Tunicata), important components of macrobenthic communities. The richness of ascidians may be underestimated due to incorrect species identification or a poor understanding of their distribution. In relation to the NMPA/BB, although the diversity of ascidians has been little studied, it is relatively high compared to other areas of the Scotia Arc, with 25 species previously reported. The aim of this study is to deepen the knowledge of ascidian diversity, based on morphological and molecular analyses, in the NMPA/BB and its relationships with adjacent areas: Tierra del Fuego (including Isla de los Estados) and the slopes of the Namuncurá/Burdwood Bank II MPA (NMPA/BB-II). The capture frequency of ascidians at 27 stations and 52 trawls (BO “Puerto Deseado” Campaign, 2016) was high (92%). So far, we have identified 42 species and obtained mitochondrial COI gene sequences (29 species) and nuclear 18S gene sequences (13 species). The ascidian affinities between different zones of the NMPA/BB (Core, Buffer, and Transition), are high (Kulczynski similarity index, 50-66%). Considering the three zones together, the similarity with stations of Tierra del Fuego reaches 50%. The similarity of these three zones is lower with respect to the slope area (NMPA/BB-II) south of the bank (16-19%), suggesting differences with depth. This information will contribute to the establishment of conservation values and the ongoing rezoning necessary for this important MPA management strategies.

650

Seasonal dynamics of dissolved nutrients in the Bransfield Strait, Antarctic

Seasonal dynamics of dissolved nutrients in the Bransfield Strait, Antarctic RAYANE MENEZES¹, Seasonal dynamics of dissolved nutrients in the Bransfield Strait, Antarctic CARLOS LENTINI¹, Seasonal dynamics of dissolved nutrients in the Bransfield Strait, Antarctic Moacyr Araujo Filho², Seasonal dynamics of dissolved nutrients in the Bransfield Strait, Antarctic Ana Cecília Albergaria-Barbosa¹

¹UNIVERSIDADE FEDERAL DA BAHIA, SALVADOR, Brazil. ²UNIVERSIDADE FEDERAL DE PERNAMBUCO, RECIFE, Brazil

Abstract

Nutrients play fundamental roles in the health and stability of marine ecosystems. Understanding the availability and dynamics of nutrients in Antarctica helps to predict and mitigate their impacts on biodiversity and local food chains. Furthermore, this continent is one of the most sensitive regions to global climate change. Studying the nutrients in Antarctica allows for monitoring climate change's effects on biogeochemical cycles and marine ecosystems. The objective of the present study was to evaluate the macronutrient concentrations in Admiralty Bay, investigating the influence of King George Island on the availability of nitrite and phosphate to the region. Surface water samples (~2 m) were collected from 12 bay areas at the beginning of the austral summer in 2019 and 2022. Filtered water nutrients were evaluated using spectrophotometric methods. Hydrographic parameters, such as dissolved oxygen concentrations, salinity, temperature, and fluorescence along the water column were obtained from CTD casts. In 2019, nitrite and phosphate concentrations ranged from 1.22 to 2.64 µmol L^-1 and 0.12 to 2.18 µmol L^-1, respectively. In 2022, they ranged from 1.82 to 2.80 µmol L^-1 and 0.24 to 0.67 µmol L^-1, respectively. These values were in the same range as those observed in the study area in previous works. Nutrient dynamics showed significant variation, with an increasing trend between years to phosphate levels. This trend was not observed with nitrite. Nutrients concentrations has not presented significant correlation (p > 0.05) with hydrographic parameters. Further analysis needs to be conducted to elucidate the dispersion patterns of these abiotic resources in the trophic chain, helping to understand how these nutrient changes may affect primary production and biomass in the region.

655

Scientific dissemination of the cryosphere with emphasis on rock glaciers. International Water Day 2024 as an opportunity to bring glaciers closer to communities at the first Water Fair.

Ms(c) Felipe Fuentes¹, Sr. Cristobal Machuca¹, Sra. Nicole Cabrera¹, Sr.- Luis López¹, Ms Nicolas Mendoza², Sr. Francisco Bucchi¹

¹Sernageomin, Santiago, Chile. ²Civur 39 volcanological center of Araucania, Pucon, Chile

Abstract

Within the framework of the celebration of Water Day in 2024, the Sernageomin Hydrogeology unit, as part of the activities around World Water Day declared by UNESCO, participated in the first Water Fair, organized by CONAPHI UNESCO Chile, in the Tupahue pool area of Parquemet. On the occasion, visitors and students from various municipal and private schools were able to learn about the past of the Mapocho River; the Water Cycle; the Hoya de Santiago aquifer, and the types of glaciers with emphasis on rock glaciers.

The motto of the water day for this year was "Water for Peace", and therefore, the workshop aimed to disseminate the most emblematic watercourse of the capital, so that passers-by could be informed about the evolution it has had. the Mapocho River, as well as telling them about its origin, in the waters of the glaciers and rock glaciers in the upper part of the basin.

The aquifers found in the sedimentary fill of the Hoya de Santiago were also illustrated. We presented 3D models and infographics so that people could see how an aquifer works and what rock glaciers are like, and understand the importance and functioning of the different components of the water cycle in the Mapocho River sub-basin.”

Carrying out outreach activities on International Water Day is an important tool and an opportunity to reflect on all the aspects of our daily lives that would not be possible without this vital element. Likewise, to advance as a society, the discussion and challenges involve asking ourselves what measures we can take today, while we face the water crisis in a context of climate change.

656

Examining the introductive pathway of non-native species into the Antarctic

phD SANGEE KIM

KOREA POLAR RESEARCH INSTITUTE, INCHEON, Korea, Republic of

Abstract

Due to its geographical isolation and extreme climate circumstances, the Antarctic environment has maintained its own ecological balance for a prolonged duration. The introduction of non-native flies into marine Antarctic environments has been attributed to recent climate change and human activity. The emergence of Trichocera maculipennis in the vicinity of Punta Arenas and its subsequent successful establishment on King George Island, along with the successive identification of new non-indigenous flies such as moss flies, have raised considerable concern.

The present study aimed to examine the introduction of non-native flies into Antarctica by monitoring insect populations at potential entry points, including ports that are frequently visited by cruise ships that supply the bases and support tourism operation and the base during two austral seasons. Under the collaboration with the Chilean Navy, we installed the UV-traps on the Aquiles naval vessel during its voyage in the Western Antarctic Ocean. A total of 27 individuals were collected at the trap placed in the harbor at Punta Arena. Significantly, a number of T. maculipennis were detected in the port samples. Several insects were captured on the Aquiles naval vessel. A total of 40 flies were captured at the Captain Artuno Prat base, Greenwich Island in South Shetland Islands. A quarter of these flies were identified as Leptocera caenosa and the species were also captured two years earlier, prompting significant concern on their subsequent establishment within the Prat base and the surrounding area.

Our results implies that the port may serve as a consistent source of these species, perhaps leading to an ongoing invasion event towards the Antarctic region. It is crucial not only to eliminate non-native species, but also to determine the routes via which non-native species enter Antarctica in order to prevent their introduction.

659

The effect of warming on the winter metabolism and energy requirements of sub-adult Antarctic krill at the Western Antarctic Peninsula

Abby Tomita, Dr. Kim Bernard, Rachel Kaplan

Oregon State University, Corvallis, USA

Abstract

Warming seawater, caused by climate change, affects metabolic processes in marine organisms, with repercussions on energy conservation, growth and reproduction, and, subsequently, population health and resilience. Antarctic krill (Euphausia superba) is an essential species in the Southern Ocean, serving as a major food source for fish, seabirds, seals, and whales, and as a mediator of biogeochemical cycles. Krill populations are abundant along the Western Antarctic Peninsula, one of the most rapidly warming regions in the world. As ocean temperatures increase in this region, it is crucial to investigate how the metabolism of krill will respond, especially during the winter months when their food is scarce and elevated metabolic demands may negatively affect their energy budget. We assessed the effect of increasing temperature on krill metabolism and energy requirements during the austral winter. Krill from the Gerlache Strait were collected and kept in ~1,300L aquarium tanks plumbed with running seawater at Palmer Station, Antarctica from June-September 2023. Individuals used in this study were fed a supplemental diet of diatoms. During August and September, eight respiration/excretion experiments were performed on individual sub-adult krill at four temperatures (-1ºC, 0ºC, 1ºC, 2ºC). Using these experimentally derived respiration and excretion rates, we then derived oxygen-to-nitrogen (O:N) ratios and calculated the minimum carbon uptake (MCU) requirements of krill at the four different temperatures. We found that there was a significant positive relationship between temperature and respiration rates, with a Q10 of 2.22. A significant increase in MCU was observed between 0ºC and 1ºC. However, in the short-term, temperature did not have an effect on O:N ratios, which were consistently above 20.4, suggesting these individuals were primarily metabolizing lipid stores. We discuss our findings within the context of the winter energy budget of sub-adult krill, with future implications under continued warming.

661

Neoproterozoic crustal evolution of Indo-Ausralo-Antarctic suture domain and Gamburtsev Subglacial Mountains in the Princess Elizabeth Land, East Antarctica: insights from the marine sediments

Dr. RASHMI GUPTA¹, Dr. Mayuri Pandey², Dr. Devsamridhi Arora³, Mr. Akash Kumar Pandey², Prof. Naresh Chand Pant⁴, Dr. Batuk Joshi⁵, Dr. Manavalan Satyanarayanan⁶, Atul Singh⁷

¹University of Johannesburg, Johannesburg, South Africa. ²Banaras Hindu University, Varanasi, India. ³National Center of Experimental Mineralogy and Petrology, University of Allahabad, Prayagraj, India. ⁴(Rtd) University of Delhi, New Delhi, India. ⁵National Centre for Earth Science Studies, Thiruvananthapuram, India. ⁶CSIR-National Geophysical Research Institute, Hyderabad, India. ⁷Inter-University Accelerator Center, New Delhi, India

Abstract

East Antarctica is composed of intricate remnants of Archean cratons with poorly defined Proterozoic suture belts. The Princess Elizabeth Land-Amery Ice Shelf (PEL-AIS) sector, the least explored regions in Antarctica, holds significant geological interest. Geophysical investigations suggest the existence of an Indo-Australo-Antarctic Suture (IAAS) linking the Africo-Antarctic domain of Eastern Dronning Maud Land to the Indo-Antarctic domain of Princess Elizabeth Land-Wilkes Land, potentially traversing near the Gamburtsev Subglacial Mountains (GSMs), hidden beneath the ice sheet in interior of PEL.

However, due to a scarcity of geological evidence, the continuity of this suture inland of PEL remains uncertain. Geochemical and zircon isotopic analyses were conducted on marine sediments deposited in Prydz Bay, collected from sites 739, 742, and 740 during ODP Expedition 119.

Sites 740, located near the coast, predominantly receive sediments from nearby coastal regions, whereas sites 742 and 739, situated farther away, accumulate sediments mainly from the intricate drainage systems of the Lambert-Amery Ice Streams. The generalised trend of chemical index of alterations and other weathering factors shows that sediments from site 740 are immature, less recycled, and more chemically weathered compared to those from sites 742 and 739.

Discriminant plots of major and trace elements reveal signatures indicative of both active and passive continental margins. Sediments from sites 739 and 742 exhibit signatures of rift setting, while those from site 740 depict characteristics of collisional setting, suggesting the occurrence of a collisional event in the PEL sector, possibly involving the Indo-Antarctic and Australo-Antarctic cratons.

Zircons from proximal sites display age ranges from Paleoproterozoic to Pan-African, whereas zircons from the distal site predominantly indicate ages ~650 Ma, hinting at the possibility of a Tonian-Cryogenian event in the hinterland of the PEL, potentially associated with the GSM. These findings contribute to understanding of crustal evolution during the Rodinia to Gondwana supercontinent cycle.

662

Analysis of the allelopathic potential of aqueous extract from two species of antarctic mosses

CAMELO, A.S. Alan Camelo, Olivera, S.C.C. Sarah Oliveira, CÂMARA, P.E.A.S Paulo Câmara

Universidade de Brasília, Brasília, Brazil

Abstract

The maritime Antarctic region is specially vulnerable to climate changes and has one of the highest warming rates in the world and, as a result, many of its areas are in the process of thawing, generating an increase in the amount of liquid water available and the growth of plants, mainly the native mosses. This warming and its consequences also favors the colonization by new plants that manage to reach Antarctica, via seeds and propagules, but are unable to establish themselves due to the harsh environment. However, it is not known whether the moss carpets present in the region offer any allelopathic effect that can stimulate or inhibit the growth of such non-native plants. The present study therefore aimed to test the allelopathic potential for aqueous extracts of the two most abundant species of mosses in Antarctica: Sanionia uncinata and Polytrichastrum alpinum. The extracts were tested separately for each species. Recent samples of the species were taken from the UB herbarium and used to prepare aqueous extracts, which were vacuum filtered and then lyophilized. The amount of 10 mg of the lyophilisate was used to prepare solutions at concentrations of 800 ppm, 400 ppm and 200 ppm, which then were applied to wheat coleoptiles for a period of 24 hours without exposure to light. The coleoptile fragments were photographed and the photos measured using the imageJ application, in order to obtain size variations and create inhibition/stimulus graphics. The results do not indicate significant allelopathic effects for the aqueous fraction of the extracts, neither for inhibition nor for stimulus. However, the methodology only contemplated water-soluble molecules and does not measure the effects of non-polar and volatile molecules, meaning new tests are needed with an adapted methodology in order to fully analyze the allelopathic potential of these plants.

664

Seven decades of Russian geophysical research in Antarctica

Dr. Sergey Popov^1,2, Dr. Alexander Golynsky³, Dr. Alexander Kiselev¹, Dr. Dmitry Vorobiov¹, Dr. Valery Masolov¹

¹Polar Marine Geosurvey Expedition, Saint Petersburg, Lomonosov, Russian Federation. ²Saint Petersburg State University, Saint Petersburg, Russian Federation. ³NIIOkeangeologia, Saint Petersburg, Russian Federation

Abstract

Russian (Soviet) geophysical studies in Antarctica began in 1956 after the opening of the Mirny research station. After this, aeromagnetic surveys and scientific traverses with a wide range of studies, including gravimetric, seismic and glaciological research, were conducted. In 1964, the geophysical method of radio-echo sounding (RES) was introduced into the practice of geophysical work. In total, these surveys covered about 5.5 mln. sq. km area of Antarctica. The RES investigations are also used in ground-based research. The reflection seismic has been used for studying the Filchner-Ronne and Amery Ice Shelves for a long time. After the discovery of the subglacial Lake Vostok, RES and seismic research were used to determine the shoreline and measure the depth of the lake. In addition, deep-seismic sounding and passive seismic methods have been used were used to study the crustal structure. These studies focused on the Lambert Rift Valley area, Dronning Maud Land and the Filchner-Ronne Ice Shelf regions. Recently, the ground penetrating radar (GPR) research has entered the practice of Antarctic studies, aimed mainly at solving engineering problems: finding suitable locations for airfields and identifying glacial crevasses along the logistic and scientific traverse routes to the Antarctic inland. The array of geophysical data accumulated during many years of Russian research made it possible to create an information basis for further development of the Antarctic Earth sciences. Besides, it also helped to identify a number of fundamental geological structures which are important for understanding the processes of formation and evolution of the Precambrian basement complexes of East Antarctica. Russian data has been successfully used by the international community in the framework of many international projects e.g. Bedmap, Admap, AntArchitecture, etc.

667

Instrumentation for on-ground East Antarctic investigations using geophysical and interdisciplinary approaches: let’s coordinate and build shared datasets!

Professor Anya Reading¹, Dr Tobias Stål¹, Assoc Professor Kate Selway¹, Dr Maria Manassero¹, Professor Matt King¹, Mr Jack Beardsley¹, Ms Shyla Kupis¹, Mr Niam Askey-Doran¹, Dr Lenneke Jong², Dr Andrew Klekocuik², Dr Joel Pedro², Dr Felicity McCormack³, Dr Sarah Thompson¹, Dr Sue Cook¹, Professor Nerilie Abram⁴, Dr Vincent Favier⁵, Ms Marine Poizat⁵, Professor Guilhem Barruol⁵, Professor Marek Lewandowski⁶, Dr Anastassiya Suhanova⁷, Professor Pavel Talalay⁷, Dr Padma Rao⁸, Dr Vikram Goel⁹, Professor Lei Fu¹⁰, Professor Masaki Kanao¹¹, Dr Tanja Fromm¹², Dr Mirko Scheinert¹³

¹University of Tasmania, Hobart, Australia. ²Australian Antarctic Division, Kingston, Australia. ³Monash University, Melbourne, Australia. ⁴Australian National University, Canberra, Australia. ⁵Universite Grenoble Alpes, Grenoble, France. ⁶Institute of Geophysics, Warsaw, Poland. ⁷St Petersburg State University, Saint Petersburg, Russian Federation. ⁸Ministry of Earth Sciences, Thiruvananthapuram, India. ⁹National Centre for Polar and Ocean Research, Goa, India. ¹⁰SUSTech, Shenzhen, China. ¹¹National Institute of Polar Research, Tokyo, Japan. ¹²Alfred Wegener Institute, Bremerhaven, Germany. ¹³Technical University of Dresden, Dresden, Germany

Abstract

The vast expanse of continental East Antarctica plays host to large regions lacking any on-ground observations, and so monitoring change in many locations is a challenge that can only be met through international coordinated efforts. This poster aims to provide a) an update on recent Australia initiatives in ground-based geophysics and interdisciplinary data collection and b) a point of connection for international collaboration going forward.

The Geophysical Research Infrastructure for AnTarctica (GRIT) Facility of Australia has been recently awarded significant funding to expand continent-based monitoring and research using multiple geophysical methods. Our pilot field deployments are underway with a focus on characterizing outlet glacier systems of East Antarctica (e.g., seismic monitoring of icequakes from the Denman-Scott) and dynamic deeper Earth foundations (e.g., seismic and magnetotelluric deployments, and telemetered GNSS on rock outcrops). In near-future years, we hope to add a good number of rock outcrop installations, and to deploy instruments further inland by linking with traverse logistics. Many data collection initiatives are active across East Antarctica led by different nations providing a strong foundation for future collaborations.

Instrument sets, such as those enabled by GRIT, are tailored to light-logistics. They have the capacity to run over the Antarctic winter, affording the opportunity to collect additional (e.g.) atmospheric and near-surface snowpack information: currently in the initial scoping phase. We aim to establish a program of rolling deployments such that continental seismic, geoelectric, Earth deformation and interdisciplinary datasets build year-by-year. Linking to the International Lithosphere Program, and extending upwards to inform both Earth-ice and ice-air interactions, this will create an international resource to support many scientific investigations and monitoring initiatives.

We welcome discussions with individuals, groups and nations interested in collaboration, and in future coordination of technical, field and research community development initiatives.

669

Safeguarding Antarctic Expeditions: The Power of Beacons and Satellites

Mr. Satyendra Kishore¹, Mr. Vikas Kumar², Mr. Raghunath P V³

¹Indian Space Research Organization, Banglore, India. ²Indian Space Research Organization, Sriharikota, India. ³Indian Space Research Organization (ISRO), Sriharikota, China

Abstract

Antarctica, renowned as the coldest, windiest, and driest place on Earth, stands as a hub for scientific exploration, drawing researchers worldwide to unveil its mysteries and comprehend its vital role in the Earth's ecosystem. Conducting fieldwork in Antarctica presents unique challenges due to its harsh conditions, often leading to distress situations for researchers. Currently, communication with base stations relies on walkie-talkies, which pose limitations such as limited range, interference obstruction etc. In distress scenarios, precise location information becomes crucial for effective search and rescue operations.

This paper proposes a novel approach to search and rescue operations in Antarctica utilizing digital coded transmitters operating at 406 MHz, commonly known as beacons, in conjunction with Medium Earth Orbiting (MEO) and Lower Earth Orbiting (LEO) satellites, along with associated ground stations and base rescue facilities. By leveraging digitally coded unique information and beacon registration databases, this system enables efficient identification of distress targets. Furthermore, near real-time location identification and distress acknowledgment services significantly enhance the chances of successful rescue operations, thereby improving survival rates while reducing logistical costs and efforts involved in rescue missions.

The proposed system offers several advantages over traditional walkie-talkie communication methods. With its ability to transmit distress signals to satellites orbiting the Earth, it overcomes the limitations of line-of-sight communication and extends coverage to remote and inaccessible areas. Moreover, the utilization of digitally coded transmitters ensures accurate and reliable distress identification and expediting rescue efforts. Overall, the integration of beacon technology with satellite communication and ground-based rescue infrastructure promises to revolutionize search and rescue operations in Antarctica, enhancing the safety and security of researchers and expedition teams operating in this challenging environment.

670

Additive Manufacturing: Opportunities and Challenges for Antarctica

Mr. Vikas Kumar¹, Mr. Satyendra Kishore²

¹Indian Space Research Organization, Sriharikota, India. ²Indian Space Research Organization, Banglore, India

Abstract

In the pursuit of advancing human exploration for Antarctica, nations worldwide are continually seeking innovative approaches to sustain and enhance their presence in driest continent on earth. Antarctica presents a formidable and remote environment for scientific research, requiring the deployment of cutting-edge technologies and innovative solutions to address the challenges posed by limited resources. For achieving this, optimizing the quantity and quality of components or parts presents a significant challenge in Antarctica, exacerbated by logistical complexities.

This conference paper proposes a comprehensive exploration of additive manufacturing techniques in Antarctic research station infrastructure to enhance sustainability, space constraint, advance planning, energy efficiency, and the overall quality of life for researchers and expedition members. Additive manufacturing offers the capability to produce parts promptly and required quantities, all while minimizing environmental impact.

Additive manufacturing, often referred to as the industrial version of 3D printing, revolutionizes modern manufacturing by layering successive materials to produce intricate parts. This technique holds particular promise in the extreme conditions of Antarctica, where customization is paramount, and production volumes are low. Parts created through additive manufacturing offer advantages viz. significant reductions in cost and lead times, introduction of novel materials and unique design solutions, reduction of component mass through efficient designs, etc.

While these techniques provide options for making sure that any part can be made as and when required in Antarctica, the choice often depends on factors such as the specific needs of the research station, environmental considerations, and available funding. Additionally, combining multiple sources of parts or components availability, may offer the most reliable and sustainable solution for logistics arrangements in Antarctica. With additive manufacturing, individual mass savings may seem modest, the cumulative effect across all logistics requirement round the year, holds the potential for substantial improvements in overall capability, reliability, and repeatability of the systems.

672

Biofilms of endophytic bacteria associated with Antarctic vascular plants

Dr Olga Iungin^1,2,3, Dr Yevheniia Prekrasna-Kviatkovska⁴, Dr Olena Moshynets², Dr Marina Sidorenko³, Oleksandr Kalinichenko¹, Dr Saulius Mickevicius³

¹Kyiv National University of Technologies and Design, Kyiv, Ukraine. ²Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine. ³Vytautas Magnus University, Kaunas, Lithuania. ⁴State Institution National Antarctic Scientific Center, Kyiv, Ukraine

Abstract

Multiple in vitro studies have shown great positive correlation between bacteria presence and activity and plants physiology adaptations, such as improvement in salt and cold tolerance of Antarctic plants. Despite the fact multiple bacterial studies conducting on planktonic cultures, the original strategy of bacterial growth is biofilm formation.

The aim of our study was to estimate biofilm formation of endophytic bacteria associated with D.antarctica and C.quitensis in a wide temperature range.

Material and methods. Biofilm formation of 12 endophytic bacterial strains isolated from Antarctic vascular plants and sampled during the 25th Ukrainian Antarctic Expedition (January-April 2020) along the Western part of Antarctic Peninsula was studied. Biofilm assay was performed in static microcosms at 4, 26, 37 and 42°C during 3, 6 days with following checking of total growth and surface attachment. CLSM analysis was undertaken using Leica TCS SPE Confocal system with a coded DMi8 inverted microscope (Leica, Germany) using fluorescent dyes.

Results. Biofilm formation of studied bacteria could be characterized by five distinct behavior types, each based on levels of biomass production and cell attachment observed across the tested temperature range. The structure of biofilms visualized by CLSM allowed to classify the different biofilms as dense, mucous, and dispersed structural types. Half of stains was highly productive and form liquid-surface and air-liquid-surface biofilms at +4°C, whereas others have the optimum of cultivation at 26-42°C. Number of species were able to form biofilms in all tested temperature conditions with the presence of impressive amounts of amyloids and eDNA. Besides, amyloids/eDNA ratio was at least 10 times higher in Gram negative compare to Gram positive biofilms with the opposite tendency refers polymers/eDNA ratio.

Conclusions. That could describe different strategies of Gram negative endophytes in plants colonization and specifically in surface attachment and biofilm scaffold formation through amyloid polymerization.

676

AntArchitecture status report: Progress towards developing a radiostratigraphically-informed age-depth model across the Antarctic ice sheets

Robert G. Bingham¹, Julien A. Bodart², Marie G. P. Cavitte³, Ailsa H. Chung⁴, Olaf Eisen⁵, Joseph A. MacGregor⁶, Rebecca J. Sanderson⁷, Johannes C.R. Sutter², Duncan A. Young⁸, AntArchitecture colleagues from around the world⁹

¹University of Edinburgh, Edinburgh, United Kingdom. ²University of Bern, Bern, Switzerland. ³Université catholique de Louvain, Louvain, Belgium. ⁴Université Grenoble Alpes, Grenoble, France. ⁵Alfred Wegener Institute, Bremerhaven, Germany. ⁶NASA Goddard, Washington D.C., USA. ⁷Newcastle University, Newcastle, United Kingdom. ⁸University of Texas Institute of Geophysics, Austin, Texas, USA. ⁹>100 colleagues, research institutions around the world, United Kingdom

Abstract

The past several hundred thousand years of the history of the Antarctic ice sheets is partly recorded by its englacial stratigraphy as detected by radar sounding. However, this radiostratigraphy has yet to be mapped and interpreted comprehensively across the entire ice sheet, and the data have yet to be fully synthesized by models attempting to reproduce the ice sheet’s past and predict its future amid anthropogenic warming.

AntArchitecture is a SCAR Action Group that is bringing together and compiling the key datasets on Antarctic Ice Sheet internal layering from the principal institutions and scientists who have been responsible for acquiring, processing and storing them over the last four decades. Key activities include coordinating data transfer and data lodging exercises between institutions/countries that will allow datasets acquired by different radar systems to be combined for pan‐continental analysis, and the development of an optimised processing flow for analysis of past data and advice on where future data acquisition needs to be targeted.

This presentation provides a status report of AntArchitecture’s programme of evaluating available radar-sounding data and suitable processing techniques, the many potential applications of a continent-wide radiostratigraphic database, and future internationally-coordinated developments needed to fully realize the value of such efforts.

An expanded outline of AntArchitecture and its timeline of activities can be accessed here: https://www.scar.org/science/antarchitecture/about/

678

Autonomous Underwater Exploration, Mapping, and Data Collection in 3D Overhead Environments: the SUNFISH Vehicle

Victoria Siegel, Kristof Richmond, William Stone, Alberto Lopez

Sunfish, Inc., Del Valle, USA

Abstract

Over the past six years, work at Sunfish has brought the capabilities of autonomous underwater vehicles to a variety of difficult-to-access underwater environments. The small, hover-capable SUNFISH® AUV is able to navigate, map, and plan in 3D using only on-board sensors. It has a small logistics footprint, but is highly capable, allowing it to get into previously unexplored places and bring back new types of data. In this paper, we describe autonomous exploration, mapping, and sampling capabilities developed for the SUNFISH vehicle to enable a variety of investigations in unstructured, 3D, overhead environments.

SUNFISH is a compact, easily-transportable vehicle, with full six degree-of-freedom control. It is able to navigate in and build fully 3D maps of complex underwater geometries such as cliffs, caves, and tunnels. The primary sensing is via a side-look multibeam sonar which can be used for survey and detailed 3D mapping. SUNFISH employs a real-time Simultaneous Localization and Mapping (SLAM) system and exploration behaviors to expand the mapped volume and safely find paths through 3D environments. This allows it to explore in zero visibility, creating precise 3D maps of areas as large as several km wide and 300 m deep, and as small as passages 2 m in diameter. Additional sensors and actuators enable water geochemistry measurements (temperature, salinity, NO3-), water sampling, high-resolution photogrammetry, and underwater intervention such as sediment sampling.

Here we report on recent applications of these capabilities, including the exploration and mapping of sea caves, and the mapping of biogeochemical parameters in large freshwater conduits. We give particular consideration to polar applications, such as the exploration and sampling of subglacial water bodies, englacial conduits, or under sea or lake ice. The application of cutting-edge autonomy can help propel the study of some of the most extreme environments on Earth.

679

Sediment Sequestration for Hot Water Drilling Cryobots

Victoria Siegel, William Stone, Bartholomew Hogan, Nathan Wright, Miriam Alexander, Samuel Weinberg, Brenda Carrillo, Scott Lelievre

Stone Aerospace, Del Valle, USA

Abstract

Stone Aerospace has built and field-tested several generations of ice-drilling cryobots (see Guerrero work in this session) with the goal of enabling exploration of the ice-covered moons of the outer solar system, as well as for enabling science investigations in thick terrestrial ice sheets and shelves. Hot water drilling is the technique of choice for deep polar drilling campaigns where ice cores are not required. In cryobot design we adapt this to a closed-cycle approach, where the cryobot pulls in local melt water, heats it, and jets the warm water to continue descent. There are several benefits to a closed-cycle hot water drilling approach for cryobots which must penetrate multiple kilometers of ice. One risk to the approach is that non-soluble materials embedded in the ice (e.g. blown sediments, volcanic ash, etc.) may accumulate at the bottom of the bore hole as these materials are freed from the melted ice by the descending cryobot. This work presents MJOLNIR, a recent NASA-funded project to develop a water-jetting subsystem that will periodically melt a side pocket lateral to the cryobot’s nose. Primary descent jetting is paused and angled jets create an off-axis pocket out of the cryobot’s descent path. Turbulent water flow moves accumulated sediments into the pocket, sequestering them there and allowing the cryobot to continue descent unimpeded. This work presents a series of experiments wherein we are seeking to optimize a side-jetting design for implementation in our bi-directional THOR cryobot design. We have created a series of different side pocket geometries in ice using different side-jetting parameters including jet diameter, jet angle, and water temperature, and have experimented with sequestering various sized particles into the pockets.

684

Using a mini ROV to document cascading effects in benthic ecosystems of the Antarctic Peninsula

Lea Katz¹, Emily Mitchell², Eliott Ramoisiaux¹, Camille Moreau¹, Henri Robert³, Ben Wallis⁴, Bruno Danis¹

¹Université Libre de Bruxelles, Brussels, Belgium. ²University of Cambridge, Cambridge, United Kingdom. ³EMC2, Brussels, Belgium. ⁴Oceans Expeditions, Ushuaïa, Argentina

Abstract

Habitat mapping using benthic imagery has already been explored in the past few years and has emerged recently as a very promising technique to document biodiversity responses to environmental variables in a quantitative way, and to highlight heterogeneity in benthic communities, providing a baseline for ongoing monitoring efforts. By taking video footage of the seafloor and using image analysis it is possible to identify organisms, map their spatial distribution and measure a range of ecologically-relevant parameters (e.g. shape, size, or biomass). Traditionally, the recording of underwater footage is handled by divers, but the limitations in depth and dive time become prominent in the context of polar studies, because of the extreme temperatures and the remoteness of the sampling locations. Using an underwater vehicle (remotely operated -ROV- or autonomous -AUV-) can circumvent these issues, while extending the surveys to deeper areas and larger surfaces. During the TANGO expeditions, we carried out fieldwork in the Western Antarctic Peninsula (WAP). Our objective was to groundtruth novel methodologies based on fine-scale ROV surveys. A mini-ROV (BlueROV2) equipped with cameras, a sonar, and a GPS, was deployed from an agile research vessel (70' motor sailboat RV Australis) and flown at constant altitude over pre-defined areas along the Western Antarctic Peninsula, either in a straight line or using a square-shaped pattern. Back from the field, still images were annotated using BIIGLE. For each image, abundance, substrate type, size and cover were recorded and synchronized with telemetry data obtained from the ROV to have depth, temperature, and geolocation. For square-shaped areas, we used Agisoft Metashape to build photomosaics of the sampling sites. Results were then used to calculate biodiversity indexes, study cascade effects with Bayesian Network Inference (BNI) and study spatial correlations using Spatial Point Process Analysis (SPPA).

686

Phosphatized soils under penguin and flying bird influence perform differently in the sea-land transfer and stock of nutrients in Antarctica

Dr. Rafael Siqueira, Dr. Márcio Francelino, Dr. Roberto Michel, Dr. Carlos Schaefer, Dr. Elpídio Fernandes-Filho

Federal University of Viçosa, Viçosa - MG, Brazil

Abstract

Phosphatization is one of the main pedogenic processes in Antarctica, especially in Maritime Antarctica. It generates soils with pronounced changes and high fertility. Although the influence of penguins has been extensively studied, we know too little about the differences between soils under the influence of penguins and other birds. In this work, we conducted a comprehensive analysis over the legacy database of the Brazilian Project Terrantar, applying non-parametrical tests (Kruskal-Wallis and Dunn tests) to compare properties of three soil groups: phosphatized soils under penguin influence (PE), phosphatized soils under flying birds influence (FB) and soils without phosphatization (NO). Overall, 2639 samples of 700 soil profiles were used. According to results, soil physical attributes were mainly associated with parent material and frost weathering and did not clearly demonstrate phosphatization effects. Regarding soil chemistry, many attributes showed the most severe weathering of the phosphatized soils, such as pH, Ca²⁺, bases sum, effective cation exchange capacity and Al³⁺, indicating higher acidity and bases leaching. Nevertheless, these attributes showed no significant differences between PE and FB soils. The main differences were related to the contents of nutrients present in the phosphatized soils. PE soils presented the greatest contents of P, K, Fe, Zn and Cu, which is directly related to the highest input of guano due to the high density and longevity of the penguin colonies. FB soils, in turn, had the highest total organic carbon and nitrogen contents, which is attributed to the high fertility of these soils combined with the better conditions for vegetation development at the current or abandoned sites. Our results show that phosphatized soils under the influence of penguins and flying birds, although subject to similar weathering effects, play a different role in terms of nutrient sea-land transfer and therefore deserve special attention regarding their ecological functionality in Antarctica.

688

Optimised Methodology of X-ray Computer Tomography Scanning for Investigating Brine and Air Porosity of Antarctic Sea Ice

Ms Hayley Swait^1,2, Dr Tokoloho Rampai^1,2

Abstract

Sea ice microstructure has cascading effects on larger-scaled systems influencing the heat, momentum and mass transfer between the ocean and the atmosphere. The porosity within ice influences the ice albedo reducing incoming solar radiation aiding in regulating temperatures. The morphology and size distribution of brine and air inclusions are influenced by the texture, temperature and salinity of the sea ice.

Analysis techniques, such as MRI (Magnetic Resonance Imaging), X-ray computer tomography (CT) scanning and thin section analysis, have been used to characterise sea ice porosity. Thin section analysis is linked to stereological implications in addition to the ambiguity between brine and air porosity. Conversely, MRI and CT techniques preserve the internal structure which leads to qualitive differentiation between porosities. Advanced CT techniques allow for high resolution analysis of these porosities leading to a qualitative description of brine and air inclusions, unlike with MRI. There are limited studies of sea ice porosity using CT techniques, these studies only report on porosity volumes, number densities and the internal diameter of these inclusions. Sea ice samples are typically stored in lower than in situ temperatures (~-20°C), for varying periods, prior to testing at standard conditions (~-10°C). Brine inclusions are susceptible to the temperature fluctuations that arise from storage and testing conditions.

This study focused on optimising high resolution CT technique in order to assess the volumes, size distribution and shape of the inclusions as a result of temperature fluctuations. Preliminary findings show an increase in number densities and a reduction in the volume of brine inclusions. Further findings indicated an additional change in the sphericity of brine inclusions which has not been reflected in current literature. Estimation of salinity and density of these sea ice samples was conducted in a way to mitigating the methodological constraints observed in other similar studies.

691

The composite hose for water return used in hot water drilling: design and test

Dr Bing Li¹, Mr Xiaobing Li¹, Dr Yazhou Li¹, Mr Yizhuo Li¹, Dr Xiaopeng Fan², Dr Da Gong², Professor Yiyong Yang¹, Professor Pavel Talalay², Professor Youhong Sun¹

¹China University of Geosciences, Beijing, China. ²Jilin University, Changchun, China

Abstract

The hot water drilling technology is the rapid drilling method to create holes in the Polar ice sheet through melt ice with hot water. The cavity is indispensable to the deep hot water drilling, and the return water hose is responsible for transporting the low-temperature water from the cavity to the surface. The inner diameter of the return water hose has a great influence on its pressure losses, therefore, the inner diameter should be determined at first combining the depth of the cavity, the flow rate of return water, during designing the return water hose. To reduce the number of cables in the return hole, we proposed that the power cables for submersible pump and power lines for sensors were embedded in the hose, and their types were determined according to the power of them. To avoid water inside the hose frozen in the process of low-flow water return, and to satisfy the demand for melting ice under extreme working conditions, it was proposed to set up the heating wires inside the return water hose at the same time, and the heating demands under different working conditions were analyzed through numerical simulation to select the type of heating wires and power supply scheme. According to the bearing capacity of the hose and the fluid pressure inside the hose, the design breaking force and working pressure of the hose were determined, and then the material selection and structural design were carried out to finalize the diameters of each layer of the hose. Finally, the main parameters of the return hose will be tested, and the working performance of the heating wires also will be tested by ice melting experiments, which will be compared and analyzed with the numerical simulation to improve the design method of the return water hose.

692

Main characteristics of the water cavity of a deep hot-water drill to explore subglacial lake in Antarctica

Dr Yazhou Li, Professor Youhong Sun, Dr Bing Li, Mr Yue Wang, Mr Xiaobing Li

China University of Geosciences, Beijing, China

Abstract

More than 600 subglacial lakes have been identified in Antarctica and most of them are unexplored. The hot-water drill is seen as the cleanest tools to access subglacial lakes beneath deep ice sheet. As one of the most important parts of a deep hot-water drill, water cavity is commonly used for installing submersible pump to circulate the cooled drilling water and to control the water level in the borehole. Water cavity is usually built by connecting the main borehole and the secondary borehole at some depth. As far as now, the building and maintaining of a water cavity are never systematically analyzed. Here, we present the main characteristics of the water cavity of a deep hot-water drill as a guidance for future subglacial lakes exploration. We suggest the diameter of the main borehole and the secondary borehole should be less than 0.4 m and the distance between them should be less than 1 m. The length of the water cavity should be at 2-3 m longer than the submersible pump. Generally, the building depth of water cavity is governed by ice sheet thickness, firn depth and snow density at surface. In Antarctica, the water cavity will be not frozen as long as the cooled water temperature is more than 2 ℃. In the case of very low ice temperature, the hot water with flow rate of 12 L/min should be injected to the water cavity to compensate the heat lost to surrounding ice.

693

Study on the drilling process and influence mechanism of hot water drilling in ice layer

Mr. Zhipeng Deng¹, Prof. Youhong Sun², Prof. Pavel Talalay¹, Mr. Yifan Yang¹, Mr. Ximu Liu¹, Dr. Da Gong¹, Dr. Xiaopeng Fan¹

¹Jilin University, Changchun, China. ²China University of Geosciences, Beijing, China

Abstract

Hot water drilling is one of the drilling methods using hot water jet with high temperature and high pressure to melt ice, which is distinguished for high rate of penetration and large diameter of borehole, thus is widely used in the drilling for observation holes in polar ice sheet and ice shelf. The maximum hot water drilling depth has reached 2500 m up to now. Energy conservation was normally used to analyze the heat transfer process during drilling and describe the influence from drilling parameters upon diameter of the whole borehole, but the process of ice melting at the bottom of borehole and its influencing mechanism are still unclear. To study this issue, a test platform for ice hot water drilling was built up to conduct a large number of experiments using transparent ice to explore how different drilling parameters (flow, water temperature and water pressure), ice temperature and nozzle parameters would influence rate of penetration, borehole diameter and drilling efficiency. The research results could provide significant guidance towards development of hot water drilling theory and optimization of drilling parameters.

697

Experimental research on frost heaving force during refreezing process of isolated cavity formed by RECoverable Autonomous Sonde

Doc. Yu Wang¹, Prof. Youhong Sun², Prof. Pavel Talalay Talalay¹, A.P. Bing Li², A.P. Xiaopeng Fan¹, A.P. Da Gong¹, Doc. Lin Liu¹

¹Jilin University, Changchun, China. ²China University of Geosciences Beijing, Beijing, China

Abstract

RECoverable Autonumous Sonde (RECAS) is an effective tool to realize sampling without contamination for Antarctic subglacial lakes. During drilling, meltwater near the upper part of the RECAS borehole will be frozen due to the cold ice around it, which would consequently lead to borehole closure. Although the situation could effectively protect the subglacial lake from contamination caused by exogenous substances, the sonde will be easily damaged from abnormal high pressure caused by refreezing of meltwater in isolated cavity if any accident cuts its power supply. Consequently, how to ensure the security of the sonde itself during drilling process is one of the key issue worth considering. Theoretical analysis revealed that the existing sonde sidewall structure could not withstand the frost heaving force from internal meltwater refreezing process. To address this issue, a pressure relief method was proposed by cutting holes on the sidewall of the sonde to transfer the internal frost heaving force outside the sonde. Three sets of scaled-down test devices were developed to study the ultimate frost heaving force during refreezing process in isolated cavity. The influence of ice temperature, overlying stratum pressure, and size (height and diameter) of water column on ultimate frost heaving force were studied respectively. Eventually, an optimized design for sonde structure is proposed based on results of the experiments, which provides a significant guidance to design of the RECAS for subglacial lake exploration.

698

Petrogenesis of the Hughes Bluff granitic pluton in the Transantarctic Mountains, Antarctica

Dr. yingchun cui

Polar Research Institute of China, Shanghai, China

Abstract

In order to elucidate the petrogenesis of the Hughes Bluff granitic pluton, the petrological and geochemical studies were conducted, and the results show that the Hughes Bluff granitic pluton is composed of monzogranite, intruded by fine-grained monzogranite dikes in the later period. They both are characterized by high abundance of silicon, alkali and potassium, enriched in Rb, Th, U and K and depleted in Nb, Ta, Nd and Ti relative to those of the primitive mantle, with the Rittmann Indexes less than 3 and the A / CNK values less than 1. They both also have a low total amount of rare earth elements and an abundance of light rare earth, showing weakly negative Eu anomaly and slightly positive Eu anomaly in the chondrite-normalized REE pattern for the monzogranite and granitic monzogranite dike respectively. All the data show that the rocks from the Hughes Bluff granitic pluton belong to the I-type granites, and the source region is probably the lower continental crust, but the contribution of mantle material cannot be ruled out. The magma in the source region underwent varying degrees of fractional crystallization of plagioclase, ilmenite, rutile and apatite, and was derived from a volcanic island arc environment related to subduction.

699

Filter feeding by Antarctic glass sponges on the Weddell Sea continental shelf – a ROV in situ study

Claudio Richter^1,2, Luisa Federwisch^1,2

¹Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ²University of Bremen, Bremen, Germany

Abstract

The Antarctic continental shelf is characterized by a unique benthos, dominated by glass sponges (phylum Porifera, class Hexactinellida). While the composition, abundance and biomass of Hexactinellida have been well investigated over the last decades, the diet, feeding rates and metabolism of Antarctic glass sponges are virtually unknown, let alone their role in carbon and silicon cycling. Using a remotely operated vehicle (ROV), we present in situ footage and data, on the pumping rates of the five most common species of glass sponges from the eastern Weddell Sea shelf. Pumping rates, determined by video tracking of fluorescent dye in situ, varied linearly with sponge biomass, irrespective of species. We calculate that an average sponge community biomass of 12.7 kg wet weight/m²filters an equivalent of 26 m³/d. With a vernal bacterioplankton biomass of 3.0-18.3 mgC/m³ and a filtration efficiency of 95%, the average sponge community uptake is 76-456 mgC/m²/d. This is equivalent to integrated bacterial carbon production in a 47-105 m water column. Considering reported sponge biomass values exceeding 100 kg/m² in some areas of the NE Weddell Sea shelf, food advection is likely limiting glass sponge blue carbon.

700

Distribution of benthic macrofauna in Martel Inlet (King George Island, Antarctica) and its connection with potential effects of glacier retreat.

B.Sc. Pedro Simoes¹, Ph.D. Monica Petti¹, Ph.D. Sandra Bromberg², Ph.D. Paulo Sumida¹

¹São Paulo University, São Paulo, Brazil. ²Oceanographic Institute of the University of São Paulo, São Paulo, Brazil

Abstract

Investigations of benthic communities in the antarctic marine ecosystem are of growing interest due to climate change. In shallow waters, ice stands out as a primary factor influencing species composition, abundance, and diversity within these communities. The rapid decline in ice volume due to climate change has the potential to reshape ecosystems, and the Antarctic Peninsula stands out as one of the most impacted regions by glacier retreat in recent decades. This study aims to investigate the spatial variability of the benthic community in Martel Inlet (King George Island, Antarctica), focusing on both ice-free areas and in areas adjacent to different types of glaciers. Sampling was conducted during the Brazilian Antarctic Operation, in February 2022, utilizing a Van Veen grab, at depths around 30 meters deep, at ten points classified by their proximity to ice-free areas (IFA), marine-terminating glaciers (MTG) or terrestrial-terminating glaciers (TTG). A total of 5811 macrofauna individuals were found, with Polychaeta, Amphipoda, and Cumacea being the most abundant groups. Eighteen families of Polychaeta were recognized, with Cirratulidae, Apistobranchidae, and Paraonidae being the most prevalent. Sampling stations in proximity to glaciers exhibited disparities in environmental data, taxonomic groups, and Polychaeta family data compared to ice-free areas, indicating the discernible impact of glacier retreat on the structure and distribution of benthic macrofauna. Results were compared with a previous study conducted in 2001 at the same sampling points, revealing an increase in organism density at TTG stations in 2022. The groups Amphipoda, Cumacea, Tanaidacea, and Cirratulidae represented the greatest comparative density increase between the years. Statistical differences were observed between the data obtained in 2022 and 2001, indicating possible alteration of macrobenthic structure with glacier retreat.

703

Heat stress in blood of Antarctic fish: Effects of warming on oxidative stress and heat shock proteins in the nototheniids Notothenia coriiceps and Notothenia rossii

Dr Cintia Machado¹, Dr Noomi Asker², Dr Maria Rosa Dmengeon Pedreiro de Souza¹, Dr Lucélia Donatti¹, Dr Joachim Sturve²

¹Federal University of Parana, Curitiba, Brazil. ²University of Gothenburg, Gothenburg, Sweden

Abstract

Knowledge of thermal limits is very important to understand the effects of climate change on the abundance and distribution of fish. Antarctic notothenids are endemic species and highly adapted to the extreme and stable cold of the Southern Ocean, therefore having a very narrow thermal window. The aim of the present study was to explore the response in the blood of Notothenia coriiceps and Notothenia rossii to warming, to discern the plasticity of these species to cope with changes in the Southern Ocean. For this, quantitative PCR assays (qPCR) were developed using as targets the genes related to the heat shock response (HSP40 and HSP90) and the genes related to antioxidants SOD, CAT and GSS. Stress markers on protein level were also measured: carbonyl proteins (PC) and total glutathione (tGSH). In the results of the present study it was possible to observe a variability between species showing that the increase in temperature induced responses of the antioxidant system in N. coriiceps and, in N. rossii, heating negatively regulated the shock proteins thermal stress HSP 40 and HSP90. Thermal stress was evident by the increase in the levels of PC in both species studied. In N. coriiceps, a negative regulation of tGSH was observed with exposure to heat, reinforcing the induction of responses from the antioxidant system in this species. In sum, the present study brought a productive comparative approach to characterize biochemical pathways linked to the thermal tolerance limits of antarctic fish.

Keywords: Notothenioid, Admiralty Bay, Heat stress, Blood

704

New offshore geophysical data on crustal structure and seabed morphology of the Pacific Antarctic margin of North Victoria Land: evidence of past to recent geodynamic processes (PNRA_BOOST Project)

Laura Crispini¹, Dario Civile², Giulia Matilde Ferrante², Michele Locatelli¹, Danilo Morelli¹, Valentina Volpi², Daniela Accettella², Flavio Accaino², Martina Busetti², Andreas Läufer³, Egidio Armadillo⁴, Ester Colizza⁵, Francesco Salvini⁶, Antonia Ruppel³

¹DISTAV - University of Genova, Genova, Italy. ²National Institute of Oceanography and Applied Geophysics – OGS, Trieste, Trieste, Italy. ³Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Hannover, Germany. ⁴DISTAV - University of Genova, GENOVA, Italy. ⁵Department of Mathematics, Informatics and Geosciences, University of Trieste, Trieste, Italy. ⁶Dipartimento di Scienze, University of Roma Tre, Roma, Italy

Abstract

New offshore geophysical data (multichannel high-resolution seismics, bathymetry and magnetics) as part of the PNRA_BOOST project (Bridging Onshore-Offshore STructures at the Pacific Coast of North Victoria Land, Antarctica: an integrated approach) were acquired on board of the OGS R/V Laura Bassi during the 38th and 39th Italian Antarctic Expeditions (Feb 2023 and 2024) off the Pennell Coast at the Pacific side of North Victoria Land, an underexplored key area at the boundary between East and West Antarctica. The preliminary analysis of the seismic and bathymetric data allows the identification and interpretation of morphological and tectonic features representing new key hints for the geodynamic evolution of the Antarctic continental margin, West Antarctic Rift System, and the influence of lithosphere dynamics on ice-sheet evolution and ice-sheet stability.

On the shelf and on the continental rise (towards the abyssal plain) NW-trending fault-bounded basement highs associated with growth strata that point to a tentative dating of tectonic activation to Oligocene times. In addition, a ca. 20 km-long ridge of basement, covered by drift deposits, revealed at a depth of about 2500 m, is bounded by faults with indications of recent tectonic activity. The observed faults could have reactivated inherited zones of weakness that separate rift blocks formed during the breakup between Australia and Antarctica. In the SW part, two broad linear volcanic zones (one belt ca. 50 km long) occur along a roughly NNW-SSE direction that is the orientation of the main tectonic lineaments inland. Several volcanoes show evidence of recent activity, and fluid-related features cut through the surrounding sedimentary successions. This volcanism correlates well with airborne magnetic observations and may represent the NNW continuation of the Mid-Miocene to Quaternary Hallett Volcanic Province forming the Adare Peninsula, or may be related to the post-spreading Pliocene-Recent volcanism of the Adare Basin.

705

Underwater upwards thermal coer: concept and preliminary design

Senior Engineer Yang Yang, Professor Pavel Talalay

Jilin University, Changchun, China

Abstract

In order to study the interaction between the ice shelves and the ocean, it is a crucial and challenging issue to study the freezing and melting process of the ice layers at the bottom of ice shelves in different Antarctic regions. In this report, the general concept of underwater upwards thermal corer for sampling the bottom part of the ice shelves is proposed. The corer can be accurately transported at specific locations after being equipped on the underwater remotely-operated vehicle. The principal components of the corer are: thermal drill head, core barrel, quick-release mechanism, and device for turning corer from travelling horizontal position to working vertical position and back. The influence of different drilling parameters (load, power, etc.) are obtained on drilling speed and ice core integrity, and the optimal drilling process parameters are optimized through the research of simulation of ice drilling process. Also, different methods of ice core breaking are compared through calculation and simulation to confirm the reliability of the method and the best integrity ice core. It is planned to verify theoretical estimations and simulation through underwater upwards coring tests.

707

Global-local Challenges & Opportunities for Antarctic Governance in the Anthropocene: Socio-technical Imaginaries and the Policy of the Future

Political Science & International Relations Lucía Wolaniuk

Universidad Nacional de La Plata, La Plata, Argentina

Abstract

This paper delves into the intricate challenges facing the Antarctic Treaty System amidst the Anthropocene era, with a keen focus on the complex dynamics of climate change and the potential exploitation of Antarctic resources. We propose an innovative approach anchored in collaborative engagement across diverse stakeholders, fostering the synergy of public-private partnerships in various levels. Our emphasis lies on establishing robust governance frameworks tailored to address the intricate interplay of global and local challenges, particularly within the Antarctic Gateway Cities, from a nuanced perspective of local development.

Drawing inspiration from the concept of socio-technical imaginaries, we prospect collectively constructed visions of desirable Antarctic futures, underscored by the imperative of sustainable environmental stewardship and a harmonious transition towards responsible resource utilization. Within this discourse, we unpack the connotations and ramifications of sovereignty in the Antarctic context, advocating for its recognition as a global common good, while critically examining the legitimacy of claims and special statutes within the Antarctic Treaty System.

At the heart of our discourse is the recognition that the complexities of twenty-first-century politics demand innovative governance instruments, capable of navigating decentralized, intangible, and ever-evolving concerns. We contend that our era needs heightened awareness of the intricate interplay between present realities and envisaged futures, understanding that imaginaries are constitutive of subjective visions and that agency is performed through them.

Our presentation advocates for a collaborative ethos within the Antarctic Treaty System, emphasizing the significance of consensus-building and cooperative strategies to surmount forthcoming challenges. We stress the importance of anticipatory and innovative management, adept at navigating shifts in governance paradigms, intervention strategies, and the very constitution of political actors amidst the evolving landscape of Antarctic futures.

710

Biosynthesis of Ce and Gd nanoparticles by Antarctic microorganism Geobacillus sp. ID-17

Mónica Acuña-Martínez¹, Jenny M. Blamey^1,2

¹Department of Biology, Faculty of Chemistry and Biology, Universidad de Santiago de Chile, Santiago, Chile. ²Fundación Científica y Cultural Biociencia, Santiago, Chile

Abstract

Biosynthesized nanoparticles (Bio-Nps) are particles with a size between 1-100 nanometers, whose biological activity depends on factors such as size, morphology and the type of reducing agent used for their synthesis. Bio-Nps synthesis uses bacteria, fungi or plants to reduce and stabilize metal compounds, generating more stable and functionally synthesized nanostructures in a more promising manner better than chemical synthesis, thanks to its apparently lower environmental impact. Among the metals that currently have the greatest implications at an industrial level are the “rare earth elements” (REE), made up of 15 lanthanides and yttrium as well as scandium. Among the REE cerium (Ce) and gadolinium (Gd) are important due to their use for the manufacture of catalysts and microwaves, respectively. Some extremophiles microorganisms are capable of synthesizing nanoparticles. One of these extremophiles is Geobacillus sp. ID-17, a gram-positive thermophilic bacillus isolated from Deception Island, Antarctica. Regarding the synthesis mechanism, it is known that it involves the capture of metals, whose metal ions are trapped where metals inside the microbial cells and then reduced to nanoparticles in the presence of enzymes and other biomolecules. Studies have determined that the formation of metal NPs, in ID-17, requires a NADH-dependent nitrate reductase that reduces the metal ion. However, the synthesis of rare earth NPs has not yet been described. The objective of this work is to analyze the formation of nanoparticles of the REE metals Ce and Gd through biological synthesis, using the extremophilic microorganism Geobacillus sp. ID-17. The characterization of the nanoparticles obtained was analyzed by means of transmission electron microscopy (TEM) and scanning microscopy (SEM) and X-ray dispersion spectroscopy (EDX). The results demonstrated that these nanostructures are formed extracellularly, presenting a spherical morphology ranging in size from 64 to 100 nm for Ce and Gd, respectively.

716

Ground Soil Temperature monitoring study in Stansbury Peninsula, Nelson Island, Antarctica.

Dr. Martin Meier^1,2,3, Dr. Rafael Gomes Siqueira², Dr. Marcio Rocha Francelino², Dr. André Thomazini⁴, Dr. Antonio Batista Pereira⁵, Dr. Carlos Ernesto Gonçalves Reynaud Schaefer², Dr. Elpidio Inácio Fernandes Filho²

¹Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF), Rio de Janeiro-RJ, Brazil. ²Soil Department - Federal University of Viçosa- UFV, Viçosa-MG, Brazil. ³Organização Cooperativa de Agroecologia - OCA, Viçosa-MG, Brazil. ⁴Universidade Federal de São João del Rei, São João del Rei-MG, Brazil. ⁵Unipampa, São Gabriel-RS, Brazil

Abstract

Permafrost and active-layer exhibit thermal behavior that can consistently reflect changes in the temperature regime of the environment. The high cost of monitoring initiatives and equipment’s used, suggest that replacing them by similar but efficient self-recording temperature sensors, can reduce costs associated. Therefore, the objectives of this study were: i) compare ground soil temperature (GST) measures; ii) evaluate if the distance from the Glacier affects soil thermal variation, and ii) compare two different thermal-monitoring systems. For these purposes, three monitoring sites were installed in Stansbury Peninsula, Antarctica in February 2018. One monitoring system (CALM) was installed composed of five Thermocouple soil temperature sensors (05, 10, 30, 50 and 100 cm). Other two Systems were composed by soil temperature Ibuttons® readers at depths of 10, 50 and 100 cm. The records were made during 21 months. Monitoring sites did vary accordingly to the region slope following a toposequence array distant 32, 183 and 590 meters from the Glacier, allocated in Turbic Cryosols. Data were registered in Data Loggers, collected in December 2019 and processed in computational R environment. Evaluation of the maximum temperatures registered by the Sensors show that the closer to the Glacier, cooler was the maximum soil temperature registered at 100 cm, comparing Ibutton 1 System and CALM System, distant 32 and 590 meters from the Glacier, respectively. The Ibutton 2 System, despite being located more closely to the Nelson's Glacier then CALM System, did register maximum temperatures above the isothermal interval of 0.5ºC. Micro-climate characteristics have great influence over soil temperature, and different GST were registered at different regions of Stansbury, having influence by Glacier proximity. Other factors as snow-cover are also important, and monitor temperature variations with depth at each grid point, or at least at points representative of different snow accumulation conditions, are recommended.

718

Detailed petrochronology of Bunger Oasis Late-Mesoproterozoic metamorphic complex, implications for tectonic evolution of Albany-Fraser – Wilkes Land orogenic belt

Mr. Nikita Borovkov¹, Dr. science Sergey Skublov²

Abstract

The Bunger Oasis area has been commonly considered as a part of Albany-Fraser – Wilkes Land Mesoproterozoic orogenic belt comprising both South-West Australian and East Antarctic landmasses which were the components of formal Rodinia supercontinent. Therefore, the detailed petrochronology for any part of such orogenic belt is sufficient for the supercontinent assemblage reconstructions. High-temperature metamorphism peak has been reported at 1190 ± 15 Ma while the age of metamorphic zircon overgrowths provided the age of 1166 ± 8 Ma. Moreover, monazite and zircon geochronology dataset has indicated that high temperatures were maintained over a significantly longer time frame (c. 1190-1150 Ma; Tucker & Hand, 2016, Tucker et al., 2017, 2018). We collected different samples representing different types of migmatites (including neosome and paeleosome) and performed U-Pb zircon geochronology (SHRIMP) and the study of trace element partitioning between zircon and garnet (experimental DREE (zircon/garnet); ion microprobe SIMS). The age of granulitc zircons (either bright rims or independent grey to bright sectorial, fire-tree shaped grains) fall within the interval of 1220-1180 Ma which is in accordance with previously published data. Black zircon rims provide the age (1150-1140 Ma) lower than the age of peak granulitic event. A comparison of the distribution of REE in zircon and garnet showed that only black zircon overgrowth with age ca. 1140 Ma is in equilibrium with garnet while zircon, whose age corresponds to the peak of granulite metamorphism, according to the distribution of HREE and Y, is not in equilibrium with garnet. Apparently, thermal events with an age of 1140-1150 Ma are the final events for the time-extended high-gradient metamorphism. For the first time, a stage of high-gradient metamorphism with an age of ca. 1150 has been established for the Bunger Hills.

720

First record of calpionellids in the Antarctic Peninsula. New insights on Jurassic and Cretaceous trans-domain correlations

Dr Rafael Lopez-Martinez¹, Dr Marina Lezcano², Professor Gustavo Lezcano³, Dr Andrea Concheyro^2,4, Sub Oficial Diego Ariel Zapata⁵

¹Institute of Geology. UNAM, Mexico City, Mexico. ²Instituto de Estudios Andinos “Don Pablo Groeber” (IDEAN), Departamento de Ciencias Geol´ogicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina, Buenos Aires, Argentina. ³Escuela No 41 Mario Benedetti. Bahia de los Abrigos 3050. Ministerio de <Educación, Provincia de Tierra del Fuego Antártida e Islas del Atlantico Sur CP 9410, Ushuaia, Argentina. ⁴Instituto Antártico Argentino, Campus Miguelete 25 de Mayo 1151, 3◦ Piso, CP 1650, San Martín, Buenos Aires, Argen, Buenos Aires, Argentina. ⁵Int Russo 1001. Gonzales Catán. Buenos Aires, Argentina. CP 1759, Buenos Aires, Argentina

Abstract

The correlation between the Austral domain and the Tethys have been problematic for years due to the high endemism of ammonites and other fossil index groups. Particularly during the Jurassic/Cretaceous transition, microfossils play a unique role, with calpionellids as the gold standard for its determination. Nonetheless, studies of calpionellid focus on the Tethyan domain and have recently been found in the Neuquen Basin (Argentina), opening a new window for the correlation of the Jurassic and Cretaceous sequences. During the Summerfield Argentinian Antarctic Campaign 2022-2023 in Longing Gap, Antarctic Peninsula, detailed work was conducted in the Ameghino (=Nordenskjöld) Formation with several stratigraphic profiles along the nunatak. As a preliminary result, we found the first record of calpionellids in Antarctica, represented by Tintinnopsella carpathica, closely associated with the nannofossil Polycostella beckmannii. This finding sheds new light on the correlation between the Austral and Tethyan domains and the dispersion routes of calpionellid during the Thithonian and Berriassin times. Work in progress includes studying several stratigraphic sections to establish an integrated calpionellid-calcareous nannofossils biostratigraphy and its correlation with other fossil groups.

721

Evaluating the Relationship between Streamflow and Hyporheic Active Layer Dynamics in Two McMurdo Dry Valley Streams

Jared Collins, Michael Gooseff

Institute of Arctic and Alpine Research, University of Colorado, Boulder, USA

Abstract

The McMurdo Dry Valleys (MDVs) are an ice-free area of Antarctica characterized by a permafrost landscape with glacial meltwater streams that flow for 6-12 weeks during the austral summer. In the hyporheic zones beneath stream channels, the active layer can be extensive, ranging from a few centimeters from the surface to over half a meter in depth. The thaw and refreeze of the active layer under and adjacent to stream channels have important implications on hyporheic exchange and associated ecological and chemical properties of the stream ecosystems. This study aims to characterize the relationship between streamflow and hyporheic active layer dynamics by comparing long-term records of streamflow with soil sensor measurements (temperature, moisture, and salinity) in two streams in the MDVs. In addition to these records, field measurements of permafrost depth and channel morphology were collected to add context to sensor data. Here we analyze the controls on depth and duration of thaw in the hyporheic zones by comparing relationships among meteorological variables, streamflow, and subsurface conditions between hyporheic and dry subsurface locations. Preliminary results suggest that meltwater plays an important role in promoting and maintaining thaw. Further, the timing of active layer thaw and refreeze are at least partly correlated with the beginning and end of flow, respectively. These results point to the importance of liquid water in facilitating subsurface ecological processes in the MDVs and beyond, a major consideration for an increasingly warmer Antarctic climate.

723

Sedimentary characterization of coastal environments on Deception Island, Maritime Antarctica

Diego Augusto Portella, Vanessa Costa, Rosemary Vieira

Fluminense Federal University, Niterói, Brazil

Abstract

Maritime Antarctica has experienced a significant increase in the regional average temperature, which has resulted in visible changes in the glacial landscape, such as retreat in the glaciers frontal zone and changes in precipitation patterns. This study aims to evaluate the sedimentation environment of Deception Island, South Shetland archipelago, based on the sedimentary characterization of coastal ice-free areas. Deception Island is a young and active stratum volcano, and has witnessed glaciers retreat, evidenced by the increased areas of frequent exposed soil. A comparative analysis was performed applying granulometric, morphoscopic, geochemical, isotopic and statistical methodologies on terrestrial sediments samples collected in four profiles at 85 to 100 cm depth, along the coastal zone: Cross Hill, Pendulum Cove and Whalers Bay during the Brazilian OPERANTAR XXXVI (2018). The granulometric analysis showed a predominance of sand and gravel fractions over the four sampling sites to the detriment of silt and clay fractions. The morphoscopic analysis indicated a predominance of very angular, angular and subangular clasts in Whalers Bay, Whalers South and Cross Hill profiles, and a mixture of angular and rounded grains in the Pendulum Cove profile. Such characteristics are indicative of a shorter distance for transportation and reworking of sediments from their source area, in addition to rapid sedimentation of particles. Fe was the element in greatest quantity in the fine fractions in all layers in the four sampling sites, which may be associated with tephra deposits. Sediments presented incipient weathering. Isotopic results suggested autochthonous and allochthonous contributions, mainly from Antarctic lichens and animal excreta, transported by meltwater flows. A change in the behavior of measured variables was observed at 60 cm depth. The current sedimentation dynamics on Deception Island were inferred to be dominated by recent volcanic activities (1967-1970), although glacial and periglacial processes such as meltwater flows and precipitation also play an important role in the formation of deposits.

727

The Antarctic Treaty Consultative Meetings and the Matters of Common Interest: Has practice outgrown the list of Article IX?

Gustavo Ramírez Buchheister

KU Leuven, Leuven, Belgium

Abstract

Article IX of the Antarctic Treaty lists in six literals the “matters of common interest pertaining to Antarctica” on which the States Parties are to consult together when meeting in what has come to be known as the Consultative Meetings. Yet, the documents circulated at the meetings are currently sorted in the Secretariat’s online database in forty-five categories, and fifteen categories are listed for Measures, Decisions and Resolutions. Have the “matters of common interest” outgrown the list of Article IX since it entered into force? This contribution will address the topics – if any – that might have been included over the years and to what extent decision-making in their regard is possible.

728

Ice-rafted debris offshore of the East Antarctic Ice Sheet in the Weddell Sea

Alejandra Vega-Gonzalez¹, Lauren Miller¹, Ryan Venturelli², Lindsay Prothro³

¹University of Virginia, Charlottesville, USA. ²Colorado School of Mines, Golden, USA. ³Texas A&M University- Corpus Christi, Corpus Christi, USA

Abstract

The Antarctic Ice Sheet (AIS) is experiencing accelerated ice mass loss, presenting significant implications for global sea level rise and the intricacies of ocean-atmosphere interactions. The marginal zones of the AIS, particularly those terminating in oceanic waters, are challenging to study despite being regions of pronounced dynamism. In this context, sedimentary deposits located on the Antarctic continental shelf and beneath the ice shelf regimes are of paramount importance. These sediments facilitate a comprehensive understanding by bridging the temporal divide between extensive paleoceanographic and glaciological archives that span multiple millennia and the relatively shorter temporal scales captured by modern instrumental datasets spanning years to decades. A focal point of this investigation is the analysis of ice-rafted debris (IRD), which constitutes anomalously coarse-grained terrigenous materials entrained and deposited by melting icebergs. IRD serves as a proxy for reconstructing past oceanic conditions, subglacial dynamics, and paleoclimatic parameters, including the magnitude and phasing of glacial-interglacial cycles. Using advanced sedimentological techniques, including physical and geochemical analyses alongside computed tomography (CT) scanning of sediment cores extracted from the Weddell Sea sector, we aim to assess IRD’s reliability as an indicator of regional oceanographic and glaciological conditions. To address this, we obtained a total of 233 samples from 8 legacy cores, stored at the Oregon State University Repository, targeting sites across the Weddell Sea shelf. We have analyzed these samples for grain size and X-ray fluorescence, to highlight the spatial and temporal variability in IRD concentration and composition, as key indicators of significant shifts in glacial dynamics and ice sheet stability since the Last Glacial Maximum (circa 20,000 years ago). By applying sedimentological techniques to legacy cores and integrating data from modern observations, this study offers critical insights into the AIS's contribution to global sea level rise and climate variability from the upper Pleistocene to the present.

732

Modulation of dynamic wind-current coupling on ocean mesoscale activity in the southwestern and southern sectors of the Atlantic Ocean

Mylene Cabrera, Luciano Pezzi, Marcelo Santini, Luciana Lima, Celina Rodrigues, Tiffany Mendonça

National Institute for Space Research (INPE), São José dos Campos, Brazil

Abstract

Currently, there is an increasing interest in using and developing coupled numerical Earth System models. Therefore, studies that contribute to improving these modeling systems and understanding ocean-atmosphere (OA) interaction processes are increasingly necessary and relevant. Thus, the main goal of this study is to improve our knowledge of OA interaction by proposing a nontraditional approach to OA coupling. The focus here is the study of the dynamic wind-current coupling on a regional scale in the southwestern and southern sectors of the Atlantic Ocean (19°S — 66°S and 85°W — 27°W). Numerical simulations were performed with a coupled regional model using the atmospheric, oceanic, and sea ice components for months of maximum and minimum Antarctic sea ice extent to evaluate the model's skill and verify the influence of the dynamic wind-current coupling on ocean mesoscale activity. For the model's performance evaluation, sea surface temperature, sea ice concentration, and surface wind were compared with satellite and reanalysis data. It was verified that the main oceanic and atmospheric features were adequately represented during the simulated periods. The influence of wind-current coupling on the wind stress was shown through positive correlations between the wind stress curl (τ_c) anomalies and surface currents vorticity (C_v), showing that an increase in C_v induces an increase in τ_c anomalies. The highest correlations were observed for the month of maximum sea ice extent. Furthermore, a decrease in oceanic mesoscale activity associated with the wind-current coupling is verified through the Eddy Kinetic Energy anomalies and the correlation between τ_c and C_v in regions such as the Brazil-Malvinas Confluence and the Drake Passage. This study shows the importance of coupled regional models for OA interaction processes studies, emphasizing the need to consider dynamic wind-current coupling to adequately represent oceanic mesoscale structures that influence the atmosphere.

734

How does substrate composition influence the benthic functional traits of an Antarctic fjord under recent glacial retreat?

Jennifer Pereira¹, Sandra Bromberg², Monica Petti², Pablo Muniz¹, Natalia Venturini¹

¹Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Instituto Oceanográfico, Universidad de São Paulo, São Paulo, Brazil

Abstract

Glacial retreat causes an increment of fresh water, sediments and terrigenous material to coastal Antarctic areas, triggering cascading effects on primary productivity, zooplankton grazing, and the exportation of fresh high nutritional food, rich in proteins and lipids, from the water column to marine sediments. Due to high fluxes of organic matter and relatively high sedimentation rates, fjords are significant areas in regulating the carbon cycle by playing a crucial role in its sequestration at geological time scales. Organism-sediment relationships are reciprocal, they modify sediment oxygenation, remineralization and carbon storage and regulate the abundance and biomass of benthic communities. Biological Trait Analysis (BTA) is a method that links community structure to ecological functions and their response to environmental drivers through species attributes. Our objective was to evaluate how the substrate composition, the functional traits of benthic polychaete communities and their relationships, vary along a spatial gradient as the distance from the direct influence of Collins Glacier increases. 10 sampling stations were selected in Collins Bay. To perform the BTA we considered these categories: body size, type of movement, mobility, feeding mode, feeding structure and fertility rate, and the five ecological functions most reported in the literature: bioturbation, secondary production, sediment stabilization, nutrient cycling and organic matter fragmentation. Nutrient cycling was the ecological function with the greatest intensity in Collins Bay, followed by organic matter fragmentation and bioturbation. Nutrient cycling showed great relevance in the inner area near the Collins Glacier with high hydrodynamic conditions and influence of meltwater. In contrast, organic matter fragmentation and bioturbation play a more important role in the deepest outer stations of the fjord, linked to great productivity and benthic-pelagic coupling, associated with depositional processes.

736

Ten years of Atmospheric Rivers identification and characteristics at Criosfera 1 remote laboratory/Central-West Antarctica

Dr. Sérgio Gonçalves Jr.¹, Prof. Dr. Heitor Evangelista², Heber Reis Passos³, Franco Nadal Villela⁴, Marcelo Sampaio³, Prof. Dr. Luciana Prado¹

¹Rio de Janeiro State University, Rio de Janeiro, Brazil. ²Rio de Janeiro State University/LARAMG, Rio de Janeiro, Brazil. ³National Institute for Space Research (INPE), São José dos Campos, Brazil. ⁴National Institute of Meteorology (INMET), Jardim Paulista, Brazil

Abstract

Atmospheric rivers (ARs) are acknowledged as narrow corridors of intense moisture and warm air transport from low to high latitudes. These meteorological phenomena, characterized by short-term events, exert significant impacts on precipitation and surface melt in Antarctica. They notably elevate temperature and moisture levels across extensive areas of the troposphere in coastal Antarctica, contributing to observed environmental changes in the West Antarctic Ice Sheet (WAIS), including glacier retreats, increased ice flows, and heatwaves. In the Antarctic climate context, heatwaves are defined as periods lasting five or more consecutive days with temperatures exceeding the 90th percentile, as determined by daily maximum, minimum, and average temperature data. These extreme heat events can profoundly affect the Antarctic environment, accelerating ice melt, altering surface albedo, and influencing atmospheric circulation patterns. The influence of ARs on Antarctic climate, particularly in the WAIS region, is significant, driving changes in temperature, moisture levels, and precipitation patterns. The interaction between ARs, ocean evaporation, and atmospheric water vapor transport plays a crucial role in shaping environmental conditions in Antarctica. Consequently, describing the characteristics, intensity, and frequency of ARs through the application of detection algorithms has become essential to assess their impacts on Antarctic regions. In this study, we analyzed temperature data collected by the remote automated measurement platform Criosfera 1, located at 84°S latitude in West Antarctica. We identified significant AR events occurring between 2012 and 2022, which led to rapid increases in air temperature at the WAIS. Furthermore, we computed the integrated water vapor (IWV) and integrated vapor transport (IVT) using specific moisture, zonal and meridional winds, and hourly pressure level data from the ERA5 reanalysis, ranging from 1000 hPa (or from the surface for higher elevations) to 300 hPa. Additionally, we present the seasonal variability of ARs and diagnose their most probable source regions.

737

Relationship between the high-frequency variability of Antarctic sea ice extent and the polar cold air incursions over Amazonia

Dr. Camila Carpenedo¹, Dr. José Leandro Campos², Prof. Tércio Ambrizzi², MSc. Ricardo Braga³

¹Federal University of Paraná, Curitiba, Brazil. ²University of São Paulo, São Paulo, Brazil. ³INNTI Environmental Consulting and Agriculture, Porto Alegre, Brazil

Abstract

The Antarctic sea ice extent (SIE) plays an important role in the formation of cold air masses that spread to South America. However, little is known about the influence of the high-frequency variability of the coupled ocean-cryosphere-atmosphere system on weather conditions in South America, especially in the Amazonia, a key region of the global climate system. Thus, the aim of this study is to investigate the role of the high-frequency variability of Antarctic SIE on the polar cold air incursions over Amazonia, during the southern winter. The results suggest that the high-frequency variability of the Antarctic SIE expansion extremes, in the Ross Sea and Indian Ocean, modulate the cold air incursion over the Amazonia 4 days and 2 days after the SIE extremes, respectively. The SIE extremes can couple with the atmosphere, inducing Rossby waves that propagate and undergo amplification downstream from the Ross Sea and Indian Ocean during such extremes. As a result, the atmospheric wave train acquires a more southern spread over South America, reaching tropical latitudes in the Amazon region after the SIE extremes. In non-SIE extreme periods, the atmospheric wave train has a more zonal spread and reaches only the extratropical latitudes of the South America. A better understanding of high-frequency variability of Antarctic SIE is important to improve the implementation of more adequate representations of atmospheric circulation in weather prediction models, increasing the forecasting ability.

738

Methods and applications of identifying glacial and marine sediment types and environments

Ella Sher¹, Adelle Thrush¹, Dr Lauren Miller¹, Dr Allison Lepp^2,1, Dr Natalia Varela Valenzuela¹

¹University of Virginia, Charlottesville, USA. ²NOAA Global Ocean Monitoring and Observing, Washington D.C., USA

Abstract

The Antarctic Ice Sheet (AIS) has been projected to experience substantial losses in mass within the next century as a result of climate change which has major implications for sea level rise. To predict how these changes will affect the landscape, it is imperative to understand the history of the ice sheet and the ocean that surrounds it. Using a combination of laser-diffraction grain size analysis and recently employed computed tomography (CT) imaging techniques, this study aims to understand changes in the ice sheet and surrounding marine environment across time and space using large analytical, quantitative, and categorical datasets and semi-automatic sediment facies interpretation approaches. We focus on sediment cores from the Amundsen Sea of Antarctica, where the largest changes in glacier ice-mass loss are currently occurring. By integrating physical properties of sediment grains and micrometer-scale resolution stratigraphy of entire sediment cores, we aim to integrate glacial-marine sedimentology and stratigraphy to better identify sediment types and depositional environments in a more efficient manner. Visually, which is still a common method to interpret sediment types in the field of sedimentology, we see clear differences in sediment types; yet, our ongoing work focuses on quantifying these differences and using those quantifications to develop algorithmic methods to aid in identifying sediment types that will be useful for the wider glacial marine geology community.

740

Teaching Antarctic meteorology in secondary school physics classes

Thaïs Rosset¹, Nicolas Schartner¹, Dr. Camila Carpenedo², Dr. Leandro Rabelo¹

¹Federal University of Technology - Parana, Curitiba, Brazil. ²Federal University of Paraná, Curitiba, Brazil

Abstract

Although Antarctica is the most remote and inaccessible region on Earth, the continent is strongly related to Brazil's climate and weather conditions. In recent decades, there has been an increase in the frequency and intensity of weather and climate extreme events in the country due to climate change. In this scenario, it is important that the population understand the causes and consequences of climate change, as well as its relationship with Antarctic Meteorology. Thus, understanding Antarctic Meteorology requires a comprehension of physical concepts related to atmospheric and oceanic dynamics and thermodynamics. Physics teaching is therefore essential for understanding Antarctic Meteorology. Although physics teaching is a consolidated field of research, few studies have addressed the subject of Antarctic Meteorology. Therefore, in this study we present the initial results of a research project that aims to understand the possibilities for teaching Antarctic Meteorology in secondary school physics classes. We hope that the development of this research will contribute to physics teachers in secondary schools and physics teacher training, offering reflections and alternatives of teaching-learning activities related to Antarctic Meteorology in physics classes.

741

Contrasting Organic Aerosols: Insights from Antarctica and the Amazon

Dr. Sérgio Gonçalves Jr.¹, Dr. Heitor Evangelista¹, Dr. Ricardo M. Godoi², Johannes Weis^3,4, Dr. Mary Gilles⁴

¹Rio de Janeiro State University/LARAMG, Rio de Janeiro, Brazil. ²Federal University of Paraná, Curitiba, Brazil. ³Physikalisches Institut, Universität Würzburg, Würzburg, Germany. ⁴Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, USA

Abstract

Antarctica is renowned as the coldest and driest ice desert globally, while the Amazon Basin stands out for its rich biodiversity. Despite their differences, both regions have recently yielded significant discoveries regarding microorganism interactions, aerosol content, and cloud condensation properties. Organic aerosols play a crucial role in climate dynamics, constituting a substantial portion of tropospheric particles. Using Scanning Transmission X-ray Microscopy with Near Edge X-ray Absorption Fine Structure Spectroscopy (STXM/NEXAFS), we examined individual particles from the 2014 aerosol campaign at Criosfera 1 module in West Antarctica (84°S latitude), and compared them with data from the Amazon rainforest. Our findings revealed a gradient of organic matter, with higher abundance in Amazonian aerosols compared to those from Antarctica. This disparity suggests a potential lack of organic aerosols in Antarctic samples, likely due to oxidation processes during transport. Oxidation reactions, primarily driven by hydroxyl radicals, can significantly alter atmospheric particle properties, impacting their reactivity, optical properties, and cloud condensation activity. Elevated NOx levels in certain locations lead to tropospheric ozone accumulation, exacerbating oxidation processes during transport. Aerosols from the Amazon exhibit intensive biosphere-atmosphere interactions and a high degree of natural diversity. In contrast, Antarctic aerosols show suppressed organic matter, potentially enhancing water uptake and impacting local environmental processes. Further studies are needed to explore organic matter presence in Antarctica, especially concerning microorganisms resilient to oxidation in polar regions. Understanding these dynamics is crucial for elucidating the role of aerosols in Antarctic climate systems and their potential impacts on regional and global environments.

742

Investigating the biological diversity of four lakes on James Ross Island (Antarctica) using DNA metabarcoding

M.Sc Kauana Beppler de Souza¹, PhD Paulo Eduardo Aguiar Saraiva Câmara²

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²University of Brasilia, Brasilia, Brazil

Abstract

Antarctica is the southernmost continent on Earth, occupying an area of around 14 million km² and is the main reserve of ice (90%) and fresh water (70%). It is one of the most unexplored regions on the planet, with a set of extreme conditions such as intense cold, drought and very oligotrophic conditions. James Ross Island is located in the Weddell Sea northeast of Antarctic Peninsula, and this island is home to the Clearwater Mesa region, which has more than 60 shallow lakes. Lakes are extremophilic and practically untouched environments, generally shallow, with waters of extreme temperatures, very transparent, receiving a high incidence of sunlight and UV rays and with low availability of nutrients. DNA metabarcoding is a tool that allows the simultaneous identification of the DNA of species present in environmental samples (eDNA). The present work aims to use this tool to characterize the biodiversity of four lakes on James Ross Island. To this end, sediment samples from the lakes were collected during the austral summer of 2019/2020 and the DNA from the samples was subsequently extracted and sequenced. As results, we obtained a total of 393,010 DNA reads, representing 107 taxa, distributed in four kingdoms. The kingdom Plantae was the most diverse, with 78 taxa sampled, followed by Chromista (19), Protozoa (8) and Animalia (1). Of the taxa sampled, 25 are new records of occurrence for the Antarctic. Among the new occurrences are six angiosperm taxa used commonly, which may reflect human action on the Antarctic continent. Through the statistical analyzes carried out, we saw that the taxonomic composition of the lakes is quite heterogeneous and that some physicochemical and geological characteristics of the lakes seem to influence this composition.

743

Southern Hemisphere sea surface temperature associated with Antarctic sea ice concentration variability

Laura Terluk, Ricardo Potozky de Oliveira, Dr. Camila Carpenedo

Federal University of Paraná, Curitiba, Brazil

Abstract

The objective of this study is to investigate sea surface temperature anomalies (SSTA) in the Southern Hemisphere related to Antarctic sea ice concentration (SIC) variability from September 1979 to 2022. The following datasets were used: SIC (NSIDC/NASA), SST (ICOADS/NOAA), and climate indices (CPC/NOAA). We calculated the Empirical Orthogonal Functions (EOF) of SIC. Through the time series of EOF scores, we identified months with negative (positive) scores ≤ -1 (≥ 1) standard deviation. We evaluated the spatial patterns of SSTA and climate indices during events with negative and positive EOF scores and one and two months after these events. The results show that during events with positive EOF1 scores, SSTA are positive in the tropical South Atlantic (September-October), which can favor convective activity of the Atlantic Intertropical Convergence Zone (ITCZ), and in the Southwest Atlantic (September-November), which can contribute to stationarity of synoptic systems propagating towards South America. In the eastern equatorial Pacific, there are negative SSTA. In the tropical (extratropical) Indian Ocean, there are negative (positive) SSTA (September-November). On the other hand, during events with negative EOF1 scores, SSTA are negative (positive) in the tropical (subtropical) South Atlantic (October-November). In the extratropical Indian Ocean, there are negative SSTA (September-November). Regarding events with positive EOF2 scores, SSTA are negative in the equatorial Pacific and much of the Indian Ocean, while they are positive in the Indonesian region (September-November). In the South Atlantic, there are positive SSTA in the tropical South Atlantic (September-November), while there is a dipole between the tropical South Atlantic (+SSTA) and extratropical Atlantic (-SSTA) (September; predominance of the positive phase of the South Atlantic Dipole). Conversely, during events with negative EOF2 scores, SSTA are positive in the western tropical Indian Ocean (September-November; predominance of the positive phase of the Indian Ocean Dipole).

748

Modifying Ice-Ocean Interactions in the New Zealand Earth System Model

Alanna Alevropoulos-Borrill¹, Robin Smith², Jonny Williams³, Stephen Cornford⁴, Nicholas Golledge¹, Anthony Payne⁵, Dan Martin⁶, Dan Lowry⁷

¹Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ²National Centre for Atmospheric Science, Reading, United Kingdom. ³NIWA, Wellington, New Zealand. ⁴University of Bristol, Bristol, United Kingdom. ⁵University of Liverpool, Liverpool, United Kingdom. ⁶Lawrence Berkeley National Laboratory, California, USA. ⁷GNS Science, Lower Hutt, New Zealand

Abstract

The Antarctic Ice Sheet is an interactive component of the global climate system. Changes in ice volume impact atmospheric circulation, the Southern Ocean radiation balance, sea ice formation, global ocean circulation and sea level. Recent technical advancements in numerical modelling have facilitated coupling of dynamic ice sheet models within Earth System Models for the first time, improving the representation of the whole climate system. The New Zealand Earth System Model (NZESM), the child model of the U.K. Earth System Model (UKESM1), includes the BISICLES ice sheet model to simulate the evolving Greenland and Antarctic ice sheets. Within the model, the ice sheets are able to interact directly with the atmosphere and ocean through the exchange of energy, water, and the evolving ice geometry. Currently, the ocean component model directly calculates sub-ice shelf melt rates within ice shelf cavities in Antarctica. However, the relatively coarse horizontal resolution of the ocean model prevents the calculation of ice shelf melt rates for floating grid cells close to grounding lines within the finer resolution ice sheet model. Here we present the NZESM ice sheet coupling for Antarctica with a modified ice shelf melt scheme that extends melt rates to all floating ice grid cells. We explore the sensitivity of the ice sheet response to changes in the sub-ice shelf melt scheme and consider the subsequent impact on the Southern Ocean.

749

Geomorphic Evolution of Fildes Peninsula: Insights from Morphometric Analysis

Pamela Cazaroto¹, Fernando Villela¹, Caik Miranda², Marcio Francelino², Carlos Schaefer²

¹Universidade de São Paulo - USP, São Paulo, Brazil. ²Universidade de Federal de Viçosa - UFV, Viçosa, Brazil

Abstract

King George Island (KGI), located west of the Antarctic Peninsula, is the largest island in the South Shetland Archipelago, and Fildes Peninsula (FP), situated south of KGI, boasts approximately 29 km² of ice-free area, setting plateaus, valleys and convex shaped interfluves. Geological studies reveal a significant transition from a warm, ice-free climate in the early Eocene to glacial conditions in the late Eocene, marking the onset of the Cenozoic glaciation period in the Antarctic continent. This transition was characterized by glacial and interglacial events. The prevailing climate significantly impacts the region's morphology, including glacier recession and valley incision. A compilation of morphometric maps (2-meter resolution) and thematic maps (geological, morphodynamic, and pedological) were used to correlate geological, pedological, and geomorphological research and to identify and interpret the evolution of geomorphic features in Fildes Peninsula. The spatialization of information and its interpolation aided in the identification of geomorphic features, particularly in the sample area west of FP, south of the Chilean Airport runway, where a detailed-scale map was developed from drone imagery (0.5 cm resolution). Interpretation ranged from the scale of FP to the scale of an area of approximately 0.09 km² with a "U"-shaped valley, one of the locations where Collins Glacier developed after its retreat. The identified features include periglacial and nival deposits and features such as: snowmelt runoff, gelifluction lobes, patterned ground, snowdrift niches, talus deposits, solifluction slopes, and snow banks and accumulations. The conclusions, based on correlations of produced and reviewed materials, were that the identified features are linked to nivation, with possible cryoplanation of the tops of the most extensive plateaus and the formation of banks and pediments at the base of respective interfluves.

751

Advances in high-resolution atmospheric modelling for the South Shetland Islands in the Antarctic Peninsula

Miluska Alejo-Mosquera^1,2,3, Christian Torres¹, Deniz Bozkurt⁴, Michael Matějka⁵, Kamil Láska⁵, Ricardo Jaña⁶, Jorge Arigony-Neto¹

¹Institute of Oceanography, Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Faculty of Environmental Sciences (FCAM), Santiago Antunez de Mayolo National University (UNASAM), Huaraz, Peru. ³Research Center for Environmental Earth Science and Technology (ESAT), Santiago Antunez de Mayolo National University (UNASAM), Huaraz, Peru. ⁴Department of Meteorology, University of Valparaíso, Valparaíso, Chile. ⁵Department of Geography, Faculty of Science, Masaryk University, Brno, Czech Republic. ⁶Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

The South Shetland Islands (SSI), located in the northern Antarctic Peninsula (AP), have experienced one of the most significant warming trends on the Antarctic continent. However, due to their small size, these islands are poorly represented by global climate models. In this context, regional climate models play a crucial role in enhancing the spatio-temporal resolution of available climate data, essential for understanding the impact of climate change on these islands. This study aims to determine the optimal configuration of the Polar Weather Research and Forecasting (PWRF, 3.9.1) atmospheric model to produce high-resolution atmospheric data (1 km horizontal resolution). Utilising the ERA5 reanalysis from ECMWF, the PWRF model was initialised and boundary conditions were provided at six-hour intervals for testing during one summer (January) and one winter (July) month in 2013. Sensitivity experiments were performed for the microphysics, cumulus, radiation schemes and topography datasets. The PWRF outputs were evaluated using various atmospheric variables collected from two automatic weather stations at Fourcade and Polar Club Glacier and King Sejong Station. Results from the PWRF sensitivity experiments revealed that employing the Morrison 2 moment microphysics and Grell Freitas or Grell 3D ensemble cumulus schemes improved accuracy and reduced bias in temperature, surface pressure, wind, and solar radiation variables. However, different PWRF configurations exhibited only a moderate representation of longwave atmospheric radiation. Additionally, high-resolution PWRF outputs demonstrated enhanced representation of precipitation, attributed to orographic influence. Future research directions include employing the PWRF model to investigate atmospheric variables relevant to glacier studies in the SSI, thereby facilitating comprehensive assessments of climate change impacts in our study region.

Key words: Regional Climate Models, Atmospheric Variables, Climate Change, South Shetland Islands.

753

Mapping vegetation cover and distribution in Antarctica: utilizing spectral analysis and orthomosaic classification

PhD Flavia Ferrari^1,2,3, Honorary Professor Barbara Bollard^2,3, Professor Andre Thomazini⁴, Distinguished Professor Sharon Robinson^2,3, Professor Marcio Francelino¹, Professor Carlos Schaefer¹

¹Núcleo Terrantar - Universidade Federal de Viçosa, Viçosa, Brazil. ²University of Wollongong, Wollongong, Australia. ³Securing Antarctica’s Environmental Future, Wollongong, Australia. ⁴Universidade Federal de São João Del-Rei, Sete Lagoas, Brazil

Abstract

To identify overall vegetation changes in Antarctica, good baseline knowledge of distribution is essential, to understand how diversity patterns and the mechanisms underlying them vary among major plant groups and areas, particularly in Antarctica. Various vegetation indices have been used to distinguish plants from soil and other substrate features in Antarctica. When imagery from off the shelf drones is only available in red, green, blue (RGB) bands, then the normalized difference index (NDI) proved to be the most appropriate index as it utilizes the green and red channels exclusively. The objective of this study was to classify the total vegetation area (comprising mosses and phanerogamic species) for a Maritime Antarctic site. The vegetation presence or absence detection and the utilization of digital image data can provide long-term information from remote areas. For Demay Point, King George Island, we generated an orthomosaic and reprojected using drone images (Phanton 4 Pro) with a resolution of 0.05 meters. Subsequently, we employed the Spatial Analyst Toolbox in ArcMap to reclassify the image, assigning new pixel values to represent vegetation, and calculated the total vegetated area. The performance of the results was measured through train maximum likelihood and the confusion matrix, through accuracy assessment points. Based on NDI analysis and high-quality images, we accessed the remote sensing with potential applications in Antarctic vegetation development, as well as ASPA monitoring, allowing detection of change through time. This reclassification of the Demay Point orthomosaic showed a vegetated area covering 0.15 km² for mosses and phanerogamic species. This index enabled us to analyse the drone imagery without significant resolution loss.

756

Paleoenvironmental changes recorded at a high-latitude across Maastrichtian – Danian shallow marine sequence from Seymour Island, Antarctica

Bruna C. Schneider¹, Rodrigo S. Horodyski¹, Karlos G. D. Kochhann^1,2, Leslie M. E. Manríquez³, Marlone H. H. Bom^1,2, Gerson Fauth^1,2, Rodrigo Do Monte Guerra^2,4, Guilherme Krahl²

¹Graduate Program in Geology, Universidade do Vale do Rio dos Sinos-UNISINOS, Av. Unisinos 950, 93022-000, São Leopoldo, Brazil. ²Instituto Tecnológico de Paleoceanografia e Mudanças Climáticas – itt OCEANEON, Universidade do Vale do Rio dos Sinos-UNISINOS, Av. Unisinos 950, 93022-000, São Leopoldo, Brazil. ³Laboratorio de Paleobiología de Antártica y Patagonia, Instituto Antártico Chileno, Plaza Muñoz Gamero 1055, Punta Arenas, Chile. ⁴Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil

Abstract

The Danian was a period of biotic recovery, after 75% of marine species became extinct during the most recent mass extinction at the Cretaceous-Paleogene (K-Pg) boundary. Paleoclimatic and paleoceanographic events, such as hyperthermals, further impacted Danian marine ecosystems. The López de Bertodano Formation (Seymour Island) was deposited in a relatively low energy shallow marine shelf conditions, and are reported well-preserved fossils. The K-Pg boundary is characterized by a glauconite-rich interval and an iridium-rich layer. We integrate sedimentary and geochemical data with fossil bivalve occurrences to characterize possible environmental drivers and depositional conditions across a high-latitude Maastrichtian to Danian. Rock samples are collected along 30 m of the Cartographic Molluscan to Cenozoic Allomember limit transition. Two positive excursions of moderate siderophile elements occur between 5 and 6m and 9 and 11m. The K-Pg interval is probably located in the first positive excursion and the second positive excursion could be related with Deccan Traps volcanism, however more studies are needed to confirm the accuracy of these events. The K/Al end K/Ti ratios show two positive excursions between 5 and 6m, and 9 and 11m interpreted as indicative of relatively dry hydroclimate conditions. These two intervals of decreased weathering intensity show a correlation with positive excursions of paleoredox proxies at the K-Pg layer and the second glauconite-rich interval, indicative of reduced bottom water oxygenation. Between 12 m and 30 m, bottom water oxygenation improved, as indicated by low Co/Al, V/Al and Cr/Al values, controlling the first colonization of macrobenthic organisms after the K-Pg extinction in the studied section. [PROANTAR: 442676/2018-2]

758

A water cycle diagram to highlight the importance of liquid water, hydrological and hydrogeological processes on, in and around Antarctica.

Dr. Simon Cox¹, Dr. Jess Hillman², Dr. Sarah Seabrook³, Dr. Rogier Westerhoff⁴

¹GNS Science, Dunedin, New Zealand. ²GNS Science, Wellington, New Zealand. ³NIWA, Wellington, New Zealand. ⁴GNS Science, Wairakei, New Zealand

Abstract

A water cycle diagram has been constructed to visually highlight the multidomain, interconnected, fluid systems of Antarctica including groundwater, subglacial water, and surficial meltwater. It was generated in response to a growing interest and increasing awareness of the importance, and climate sensitivity of liquid water on the continent. The simplified diagram aims to depict key processes of liquid water involvement across the continent within, and between, the atmosphere, cryosphere, biosphere, geosphere and oceanic hydrosphere.

Although water cycle diagrams have been previously constructed for continents and processes at lower latitudes, the circulation of water within and from Antarctica is unique and deserving of special attention. Liquid water is fundamental for the origins of life and influences biogeographic regionalisation, ice dynamics, and surrounding oceanography.

Changes to the water cycle are inevitable with climate change and will cause widespread impacts on the Antarctic continent locally. As basal melt increases and shifts to groundwater occur, an understanding of changes to meltwater and subglacial fluid flux to the marine environment will be essential to our accurate prediction of oceanographic processes, carbon sequestration, and even sea-level rise. Knowledge gaps include the extent to which ice-melt will emit greenhouse gas, destress sub-glacial sediment and continental bedrock, enhance sub-ice deformation and alter ice-dynamics, or increase infiltration to groundwater. How much groundwater can be stored beneath the icesheets and within bedrock porosity before the continent’s capacitance is full, leading to accelerated runoff that ultimately contributes to sea-level rise?

A draft version of the water cycle diagram is provided at the poster session. The author’s welcome feedback (via scribbles, sticky notes, or email) on any key processes that may have been missed or overlooked, so that it can ultimately provide an overview and outreach tool describing the key pools and fluxes of water on, in and around the icy continent.

759

La Antártida en los programas educativos de ArgentinaGustavo Adolfo Lezcano, ¹ Teresa Romina Magalí Lemos Pereyra, ² Néstor María Franco, ³ Carlos Pedro Vairo. ⁴

Antarctica in educational programs in Argentina Gustavo Adolfo Lezcano¹, Antarctica in educational programs in Argentina Teresa Romina Magalí Lemos Pereyra¹, Antarctica in educational programs in Argentina Nestor María Franco¹, Antarctica in educational programs in Argentina Carlos Pedro Vairo²

¹Ministerio de Educación, Ushuaia, Argentina. ²Museo Marítimo, Museo del Presidio, Museo antártico José María sobral, Ushuaia, Argentina

Abstract

Abstract. A teaching outreach program on Antarctica is presented, which is subdivided into four didactic subprograms, which are characterized and general guidelines are presented. It is innovative because most of them are updated courses, through the publication of educational videos in different social networks. It is focused on promoting knowledge of the white continent and emphasizing the importance of climate change in the southern region.

With didactic information, it is intended to train teachers on Antarctic issues, promoting interdisciplinary and collaborative learning proposals with the use of various literature, maps, stories, interviews with the protagonists of scientific expeditions, video supports,

providing them with tools to develop dynamic and flexible pedagogical proposals in accordance with the diversity of the educational levels in which they teach.

The programs under development are: Education in the Museum, Let's Talk about Antarctica, Let's Talk about Science and Antarctica Knowing to Teach. The first three programs have been recognized and declared of Educational Interest by the Ministry of Education and the Legislative Power of the Province of Tierra del Fuego, Antarctica and South Atlantic Islands, as well as by the Hall of the City of Ushuaia.

Through these programs, more than 150 teachers have been trained in Antarctic issues (2021-2023), allowing them to take the content to the classrooms of the province of Tierra del Fuego, other Argentine provinces and also Latin American and Caribbean teachers.

762

An overview of the Antarctic humanities and Antarctic Social Sciences in Chile.

Dr. Gustavo Blanco-Wells^1,2, Dr. José Barrena³, Dr. Alberto Harambour¹, MSc Ximena Vergara¹

¹Centro IDEAL, Universidad Austral of Chile, Valdivia, Chile. ²Centro de Ciencias del Clima y la Resiliencia, Valdivia, Chile. ³Universidad Austral of Chile, Valdivia, Chile

Abstract

Antarctica is a continent on which there are multiple national geopolitical interests that have been partially regulated by the Antarctic Treaty. Over the years, both scientific research and the military presence have increased remarkably in Antarctica. In recent decades, tourism has growth steadily alerting scientists and conservationists about its potential impacts. Although the increasing presence of human activities and sectors, scientific research in Antarctica has mainly focused on biophysical topics in terrestrial and marine environment, with scarce attention to social studies -but in the case of legal approaches. To fill this gap, we developed a systematic review of the most recent Chilean production about Antarctica by disciplines of the social sciences and humanities. The thematic lines addressed, the emerging research problems and the main research groups contributing to the examination of social processes and phenomena on the southernmost continent are reviewed.

765

Science in Antarctica: Bridging the gap between science and the public through film and storytelling

Mr John Weller

Only One, New York, USA

Abstract

In the depths of the Southern Ocean and on the unimaginable expanses of Antarctic ice, stories are playing out right now that will determine the very future of our planet and civilization. Many of these stories are hard to hear and understand, and Antarctica is far away from the daily reality of most people. But hear these stories we must, and there are only a few people who can tell them – the scientists who have devoted their lives to understanding the ice and winds, the ocean currents, whales, phytoplankton, krill, birds and the web of interconnections that tie them, and all of us, together. These vitally important voices are rarely heard by the general public.

Science in Antarctica, an ongoing series of short films, is a compendium of stories, critical to understanding not just the fate of the Great Southern Continent, but our own fate, and what we must do as a global society to adapt to the fast-coming changes. The films aim to help bridge the gap between scientists and the public by both highlighting cutting-edge research and providing the in-depth context necessary to understand the importance of Antarctica to crucial global systems upon which we all depend. Just as importantly, the films are not solely vernacular renditions of the most important science happening in Antarctica, but also the personal stories of these scientists, presenting them as characters, rather than narrators.

Drawing on his 20 years of public outreach on Antarctica, and having now created and distributed eight episodes of this series – with more than a million views and counting – director John Weller will share a multi-media presentation of his experiences in, and important insights into, Antarctic science communications, illustrating the potential for these stories, and the scientists themselves, to truly connect with audiences and change public perceptions.

768

Exploring Atlas Antarktiki: A Distinctive Repository of Historical Antarctic and Southern Ocean Data

Tobias Stål^1,2, Shyla Kupis^1,2, Anya M. Reading^1,2, Levan Tielidze^3,4

¹School of Natural Sciences (Physics), Hobart, Australia. ²Australian Centre for Excellence in Antarctic Science (ACEAS), Hobart, Australia. ³School of Earth Atmosphere and Environment, Monash University, Clayton, Australia. ⁴Securing Antarctica's Environmental Future (SAEF), Clayton, Australia

Abstract

The International Geophysical Year (IGY) of 1957-1958 marked a significant milestone in shaping our understanding of Antarctica and the Southern Ocean. Valuable data collected during this period by contributing nations shed light on the region's complex properties and processes. The involvement of the Soviet Union was pivotal for this success.

The culmination of the IGY efforts led to the publication of Atlas Antarktiki in 1966—a comprehensive monograph that presents a unique record of extensive observations of Antarctica and the Southern Ocean. This atlas, accompanied by a textbook, provides historical data relevant to various disciplines, including glaciology, biology, meteorology, and oceanography. Its exceptional cartography and data visualisation continue to impress, often surpassing modern standards.

We reintroduce Atlas Antarktiki and its data to the current research community. We offer georeferenced and extracted maps in accessible formats for integration into contemporary GIS research applications. We also provide selected translations of abstracts, legends, and descriptions. Data includes mapped glacial features such as ice shelf edges, air and water temperatures, and observations of birds and other marine species.

769

Geomorphological surveying and multi-scale mapping in Martel Inlet, King George Island

Dr Luiz Felipe Velho¹, Dr Carina Petsch², Dr Kátia Kellem da Rosa³, Dr Cleiva Perondi³, Dr Rosemary Vieira⁴, Dr Jefferson Cardia Simões³

¹Federal Institute of Education, Science and Technology of Rio Grande do Sul (IFRS), Campus Porto Alegre, Porto Alegre, Brazil. ²Universidade Federal de Santa Maria, Santa Maria, Brazil. ³Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁴Universidade Federal Fluminense, Niterói, Brazil

Abstract

The Maritime Antarctic region has been undergoing rapid environmental changes in recent decades with the expansion of ice-free areas. These changes help to identify geomorphological features, which allow us to monitor the stability or evolution of these environments. The ice-free areas in several drainage basins in Martel Inlet have expanded in the last ten years, and some geomorphological features have been mapped using orbital images (Landsat 5 and 8, and Sentinel 2). Earlier local mappings were not supported by sedimentological analysis. Additionally, many of these maps did not cover the whole Martel Inlet. Thus, this work aimed to produce an accurate multi-scale geomorphological mapping of the area. To achieve this goal, we follow these steps: (i) standardize the existing mapping; (ii) obtain UAV imagery to identify geomorphological features on the glacier front; and (iii) conduct granulometric and morphoscopic analysis of the sediments. The geospatial data from the previous mappings was standardized, enabling its use with other datasets. In the southern summers of 2023 and 2024, UAV imagery was taken of the Dragon, Wanda, Professor, and Dobrowolski glaciers in the Admiralty Bay area, and 70 sediment samples were collected. Initial results indicate that the ice-free areas have features such as flutings, eskers, moraines, striated pavements, lakes, and thaw channels. Many of these features were not mapped previously, as free imagery such as Landsat and Sentinel do not have adequate spatial resolution for detailed geomorphological surveys. Sediment analysis is currently in progress and will provide the necessary information to finalize the detailed geomorphological mapping of the study area. By comparing current and historical data, it is possible to understand geomorphic processes in ice-free areas better and to define a maximum mapping update interval that allows for more precise surface evolution recording and monitoring.

770

Ionic Impurities in Polar Snow and Ice: Insights from a shallow core near Pine Island Glacier ice divide, West Antarctic Ice Sheet

Msc Ronaldo Bernardo^1,2,3, Msc Andressa Marcher^1,2,3, PhD Franciele Schwanck^1,2,4, Msc Isaias Thoen^1,2, PhD Filipe Lindau^1,2, PhD Jefferson Simoes^1,2, PhD Francisco Aquino^1,2, Msc Rafael Silva^1,2

¹CPC - Centro Polar e Climático, Universidade Federal do Rio Grande do Sul., Porto Alegre, Brazil. ²INCT da Criosfera - Universidade Federal do Rio Grande do Sul / INCT da Criosfera, Porto Alegre, Brazil. ³PPGEO - Graduate Program in Geosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁴IPH - Instituto de Pesquisas Hidraulicas - Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Abstract

Ionic compounds, primarily comprising inorganic acids and salts, constitute major chemical impurities found in polar snow and ice. Measurement of these ionic impurities in ice cores enables the assessment of both short-term fluctuations and long-term trends in atmospheric and terrestrial sources of such impurities. This study presents preliminary findings regarding the ionic content extracted from a shallow core (TT07, depth: 19.12 m) obtained near the Pine Island Glacier ice divide on the West Antarctic Ice Sheet (79°55’ S, 94°21’W; 2,100 m a.s.l.) during the 2014/2015 austral summer Brazilian Traverse to WAIS expedition.

A total of 724 samples were analyzed at the Polar and Climate Center IC Lab (UFRGS, Brazil) for anions and cations using two Dionex conductivity measuring instruments (models ICS-2000 and ICS-2100) configured in simultaneous injection mode with an auto-sampler. The precision of the ionic analysis exceeded 90%. Spanning approximately 39 years with an estimated error of ±1 year (1975–2014), the 19 m core record reveals distinct seasonal variability in major ionic species (Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl^-, nssSO₄^2-, MS^-). The concentrations of ionic content at the core site are influenced by seasonal climatic variations (summer/winter), transportation distances, and natural sources of these aerosols.

Moreover, an average accumulation rate of 0.23 m w. eq. y-1 was observed. This study also examines the cross-correlation between the ionic signal and accumulation records from TT07, alongside the time series of the Southern Annular Mode (SAM) index, Multivariate ENSO Index (MEI), and sea ice extent (SIE), aiming to ascertain whether the TT07 data align with circulation anomalies contributing to temperature trends, sea ice dynamics, and glaciologically significant ocean circulation changes observed in recent years.

771

Relationship between chlorophyll concentration and bacterioplankton size structure in a coastal environment at Laurie Island (South Orkney Islands)

Bachelor Claudio A. Franzosi¹, Dr. Viviana A. Alder^2,3,4

¹Instituto Antártico Argentino (Dirección Nacional del Antártico, MRECIC), Buenos Aires, Argentina. ²Instituto Antártico Argentino (DNA, MRECIC), Buenos Aires, Argentina. ³Dpto. Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales (Universidad de Buenos Aires), Buenos Aires, Argentina. ⁴IEGEBA (UBA-CONICET), Buenos Aires, Argentina

Abstract

Abundance, biomass and size structure of bacterioplankton (<0.5, 0.5-0.75, 0.75-1 and >1 µm) in the water column of three coastal sites within Scotia Bay (Laurie Is., South Orkney archipelago) were analyzed in relation to total chlorophyll concentration from late January to early March 2018. Major findings include: a) chlorophyll (range: 0.18-5.4 mg.m^-3) decreased with the daily shortening of sunlight hours; b) nitrite+nitrate (range: 13.5-24.6 µM-N) and silicate (range: 45.6-70.6 µM-Si) were significantly and negatively correlated with chlorophyll, while phosphate (range: 0.9-1.8 µM-Si) did not show any correlation; c) total bacterioplankton biomass (range: 7.09-41 µgC L^-1), and especially the 0.75-1 and >1 µm size fractions, tended to decrease as the summer progressed and showed a significant positive correlation with chlorophyll; d) although bacterioplankton density (range: 3x10⁵-8.7x10⁵ cells ml^-1) as a whole did not exhibit a clear temporal trend, large cells (0.75-1 and >1 µm) decreased in percentage with the increase of small cells (<0.5 and 0.5 - 0.75 µm), with both categories being associated significantly (p<0.0001) with chlorophyll though with a different type of correlation (positive and negative, respectively); e) The most pronounced changes in density and biomass were recorded for large and the smallest cells (< 0.5 µm), which surpassed the former ones from mid-February to early March. These results suggest that despite the existence of alternate carbon sources linked to penguin colonies or glacier meltwater discharge, the bacterioplankton uses mainly carbon of phytoplanktonic origin, which would thus exert a bottom-up control reflected in size structure changes.

774

Niche modeling of Antarctic cormorants in the face of climate change on the Antarctic Peninsula.

PhD student Raiane Amorim, PhD Antoniel Fernandes, PhD Gisele Dantas

Pontifical Catholic University of Minas Gerais., Belo Horizonte, Brazil

Abstract

Climate change represents one of the most significant difficulties for the global ecological balance and the conservation of biodiversity, resulting in effects that can lead to drastic changes in the distribution of species and a reduction in the genetic diversity of the population. In this work, we evaluate the future distribution of Leucocarbo bransfieldensis, a seabird endemic to the Antarctic Peninsula, for the period 2090 - 2100. To this end, we carry out modeling recovering spatial data on the occurrence of reproduced colonies of cormorants in the GBIF, complemented with additional recorded data on scientific expeditions. We used the environmental variables from Bio Oracle 2.2. We analyzed the data in the MaxEnt algorithm for three representative scenarios of the greenhouse gas concentration pathway (RCP45, RCP60, and RCP85). The models were specific to the respective extents under current and future sea conditions and with AUC <0.9. As a result, the variables that had the most influence on the modeling for the three scenarios were ice thickness, followed by temperature and salinity. Regarding the size and location of the suitability area for L. bransfieldensis, the RCP6.0 scenario showed a drastic reduction of 63.5% of the are the distribution of this species, demonstrating suitability for East Antarctica in the Weddell Sea. Two other models showed an increase in area of 8.8% (RCP4.5) and 8.7% (RCP8.5) with displacement to areas such as Marguerite Bay. Thus, our analyses indicate that climate change may interfere with the distribution of this species with the displacement of the suitable regions to colder locations and/or locations that do not yet occur. The scenarios also highlight uncertainties about possible climate changes and facilities, such as areas of suitability for the species in the face of interspecific competition, areas suitable for nesting, and availability of food, among others. However, it is certain that marine life, such as L. bransfieldensis, will be significantly affected.

775

Modelled Earth system feedbacks associated with the West Antarctic ice sheet during the last interglacial period

Frank Mackenzie^1,2, Dr Elizabeth Keller^2,1, Professor Nancy Bertler^1,2, Professor Nicholas Golledge¹

¹Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ²GNS Science, Lower Hutt, New Zealand

Abstract

The Last Interglacial (LIG, c 130 – 116 ka) was characterised by greenhouse gas concentrations akin to pre-industrial levels but with global mean air temperatures 1-2°C warmer and global mean sea level 6-9 metres higher than present day (Dutton et al., 2015). A substantial portion of this sea-level rise may be attributed to a diminished Antarctic ice sheet (Dutton et al., 2015; Quiquet et al., 2013), highlighting the vulnerability of the West Antarctic ice sheet (WAIS) to relatively small increases in temperature. Despite this, current modelling efforts often use modern ice sheet configurations, potentially impacting model reliability (Otto-Bleisner et al., 2020, 2021).

This study employs the intermediate-complexity UVic ESCM to simulate LIG conditions with a modified WAIS, derived from an ice sheet model simulation with LIG boundary conditions (Golledge et al., 2021). We assess the global impacts of a reduced WAIS. Using the RICE ice core and other ice core and marine sediment records, we also evaluate whether modifying WAIS in line with the ice sheet model simulation enhances model-proxy agreement.

Preliminary findings indicate that modifying the ice sheet in UVic ESCM induces warming in the Southern Ocean surface, alters the temperature and salinity structure of the Ross Sea, and affects the Atlantic meridional overturning circulation. These results underscore the significance of incorporating modified ice sheet configurations in paleoclimate modelling, potentially providing a framework for future investigations with higher-complexity models.

776

Antartic extremophiles: An alternative for the biosynthesis of ferromagnetic nanoparticles

Valentina Antunez - Ossio¹, Dra. Jenny M. Blamey^1,2

¹Universidad Santiado de Chile, Santiago, Chile. ²Fundacion Biociencia, Santiago, Chile

Abstract

The development of new alternatives for the synthesis of nanoparticles (NPs) has been of great interest. Chemical synthesis has traditionally been employed; however, this requires the use of numerous toxic reagents, resulting in the production of environmentally harmful residues. Biological synthesis of nanoparticles has emerged as a promising alternative. The primary objective of this work is to demonstrate the capability of two extremophilic microorganisms, isolated both from low temperature extreme Antarctic environments, belonging to genera Pseudomonas and Geobacillus, in the biosynthesis of ferromagnetic NPs, both intra and extracellularly. For the biological synthesis, two types of iron salts, FeSO_{4 ×} 7H₂O and FeCl₃_× 6H₂O were used as metal precursors. In order to optimize the synthesis process various factors that influence the NPs synthesis were studies. These include pH range from 2 – 7, temperature range of 25 - 65°C as well as precursor concentrations 1 - 10 mM iron salts. These studies were carried out using three different culture media: LB, TGY, TSB and 9K. The magnetic properties of the generated NPs were evaluated during the different bacterial growth phases, using a neodymium magnet as an external magnetic field. So far, the bacterial NPs have been characterized through UV-Vis spectroscopy, scanning electron microscopy (SEM) coupled to X-ray scattering spectroscopy (EDX). The formation of the ferromagnetic NPs was confirmed through SEM/EDX. The iron concentration and pH of the media were the most critical parameters for the biosynthesis magnetic NPs. These bacteria proved to be capable of synthesizing iron oxide nanoparticles with unique magnetic properties, making them promising candidates for use in various applications.

778

DNA metabarcoding as tool for detecting invasive plant species in Antarctica

Dr Micheline Silva¹, Dr Peter Convey², Dr Luiz Rosa³, Dr Fabyano Lopes⁴, Dr Paulo Camara^1,5

¹Universidade de Brasilia, Brasilia, Brazil. ²British Antarctic Survey, Cambridge, United Kingdom. ³Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ⁴Universidade Federal do Tocantins, Porto Nacional, Brazil. ⁵Universidade Federal de Santa Catarina, Florianopolis, Brazil

Abstract

Many organisms do arrive in Antarctica but does not establish mostly due to the unfavorable climatic conditions. As changes in climate become more evident in the Antarctic peninsula region, more ice-free regions will become larger and may provide a more suitable environmental conditions for alien species that currently are reaches the region but are unable to establish due to the local harsh conditions. However, as such climate conditions become less harsh, new comers will eventually thrive with unexpected consequences for local native biota. Diaspores brought either by wind, birds or humans are usually hard to identify and demands taxonomic expertise in many different biological groups. DNA metabarcoding allows a quick and effective way of producing species lists for a wide range of organisms, including taxonomically challenging as microalgae that can only be identified using culturing methods, pollen, spores and resting stages. Our studies using environmental DNA from soil, so far have revealed the presence of 47 exotic Angiosperms, being 07 from the Maritime Antarctica and 40 from the Continent. Also, numerous other exotic microorganisms were found. Even though the presence of DNA does not necessary imply the existence of a viable organism, it does suggest that plant propagules do circulate in the air and reaches Antarctica more frequently than expected and that a long term monitoring is needed as climatic conditions in the region are becoming milder and therefore more suitable to the establishment of alien new comers.

779

Laurie Island Plankton Observatory: one decade of studies

Dr. Viviana A. Alder^1,2,3, BSc Claudio A. Franzosi¹

¹Instituto Antártico Argentino (Dirección Nacional del Antártico, MRECIC), Buenos Aires, Argentina. ²Dpto. Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. ³IEGEBA (UBA-CONICET), Buenos Aires, Argentina

Abstract

Antarctica is a unique region not only because of its vulnerability to increased global temperatures but also as a triggering source of environmental and biotic changes at different scales. The complex community of organisms that constitute the Antarctic marine plankton, essential for climatic, biogeochemical and trophic web processes, is noted for its short response times to environmental changes within ecosystems. From this perspective, a decade ago we began the ecological study of plankton from a coastal ecosystem in the South Orkney Islands archipelago. The observation site lies in Scotia Bay (60°44’S; 44°43’W), located south of Laurie Island’s isthmus and facing towards the Weddell Sea. The isthmus hosts Orcadas Base (Argentina), which represents the oldest stable human presence on the continent and the longest uninterrupted series of meteorological data south of 60°S. In collaboration with various institutions, the structure of plankton is being explored by year-round samplings aimed at detecting changes in the abundance, biomass and dominant species of organisms from bacteria and phytoplankton to protozoa and occasionally zooplankton. The main purpose of these investigations is to assess the influence of meteorological, oceanographic and sea ice conditions on these communities, and determine the degree to which planktonic temporal fluctuations are associated with changes at the local and regional scale. Almost permanently, the results being obtained prompt the formulation of new scientific questions and emphasize the importance of sustaining long term studies intended for documenting and understanding the changes in biodiversity, biomass and the role of plankton under normal or anomalous conditions. Laurie Island Plankton Observatory is the only one of its kind in the South Orkney archipelago, and is therefore expected to become a benchmark in the study of Antarctic coastal ecosystem productivity.

780

Coherent Brazilian coast sea level response to the Southern Annular Mode

Dr Venisse Schossler^1,2, Msc Rafael C Silva^1,2, Dr Jefferson C Simões^1,2, Dr Francisco E Aquino¹, Bsc Pedro H R Lira^1,2

¹Centro Polar e Climático - Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²INCT da Criosfera, Porto Alegre, Brazil

Abstract

Several studies account for the influence of the Southern Annular Mode (SAM) on the sea level (SL) of the southern oceans. Therefore, dynamic SL variations on the wide Brazilian coast were studied, and their relationship with the SAM was investigated. For this, we use altimeter data (1993–2022) post-processed by X-TRACK (CTOH/LEGOS, which includes filters and corrections) and gridded altimetry data from Copernicus (ECMWF). We observed the wind (u and v) and pressure fields (ERA 5), wind stress curl, and Ekman transport (U.S. Navy Fleet Numerical Meteorology and Oceanography Center - FNMOC) as well as the SAM index (MARSHALL 2003). Coherent SL variations were detected for the four different geographic regions of the Brazilian coast. The coherent variations had significant positive correlations with the SAM index. Coherence was significant for periods of 30 years across all regions. The most coherent correlation is with the states in the southern region of Brazil. The positive correlation is consistent with the mechanism of stronger westerlies, which induces greater northward Ekman transport. This process causes divergence over the Southern Ocean and convergence towards subtropical latitudes, causing downwelling over the southern coast of Brazil. At the same time, the positive SAM strengthens the easterly winds in the South Atlantic subtropical high, proven by the positive correlation between SL and the zonal wind. If the positive SAM trend persists as predicted, this coastal plain and its population are at serious risk of being impacted

782

Moss mats as an important factor for species conservation in Antarctica

DR Paulo Camara^1,2, Msc Fabio Bones², Dr Fabyano Lopes³, Dr Peter Convey⁴, Dr Micheline Silva¹, Dr Luiz Rosa⁵

¹Universidade de Brasilia, Brasilia, Brazil. ²Universidade Federal de Santa Catarina, Florianopolis, Brazil. ³Universidade Federal do Tocantins, Porto Nacional, Brazil. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Universidade Federal de MInas Gerais, Belo Horizonte, Brazil

Abstract

The term bryosphere refers to a series of poorly known organisms that lives associated with moss carpets (e.g. Springtails, Tardigrades, Nematodes, Ciliates, microalgae, fungi, bacteria, etc). Moss carpets houses a big, but poorly known, diversity and maybe even new organisms, also, such carpets may house new and potentially invasive or pathogenic organism form whom we know virtually nothing. During the construction of the new Brazilian Antarctic Station Comandante Ferraz, some moss carpets were transplanted from its original site in order to avoid its destruction. To better access the associated biota transplanted with the moss carpet, our group have extracted DNA from both a transplanted and non-transplanted moss carpets in King George Island in Maritime Antarctica. We used DNA metabarcoding as a quick and effective tool for producing species lists for a wide range of organisms and to better understand the role of moss carpets in housing diversity in the region. Our results have shown that a transplanted moss carpet housed 263 taxa from five Kingdoms (Chromista, Fungi, Metazoa, Protista and Viridiplantae), two Domains (Archaea and Bacteria) and 33 Phyla associated with the carpet. This diversity included one Archaea, 189 Bacteria, 24 Chromista,19 Fungi, eight Metazoa, seven Protista and 16 Viridiplantae whereas a non-transplanted one housed found 346 taxa among five Kingdoms and 33 phyla. Our preliminary data suggests that transplanting a moss carpet may results in loss of diversity in its associated bryosphere at the same time as show the high relevance of moss mats as important sites for housing local organisms and therefore plays a yet poorly understood role in species conservation.

787

Working towards a Red List for Antarctic Endemic Bryophyta using IUCN criteria

Maria Clara Gil Laydner¹, Clara Katharina Vaz da Silva¹, Eduardo Toledo de Amorim², Paulo Eduardo Aguiar Saraiva Câmara¹

¹University of Brasilia, Brasília, Brazil. ²Centro Nacional de Conservação da Flora/Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (CNCFlora/JBRJ), Rio de Janeiro, Brazil

Abstract

The knowledge about Antarctic vegetation is limited due to the extreme conditions of the continent, but recent research has revealed important discoveries about its biodiversity. Antarctic bryoflora has generally been considered to have a low threat level. However, this may not be true for rare species. Considering this, our study sought to understand the current conservation status of the five endemic species of Antarctic mosses: Coscinodon lawianus, Schistidium lewis-smithii, S. steerei, S. leptoneurum, and S. deceptionense. By assessing their extinction risk following IUCN criterias and categories system, the endemic species S. lewis-smithii and S. leptoneurum met Vulnerable category (VU), while C. lawianus, S. steerei and S. deceptionense were listed in the Data Deficient (DD) category. This diagnosis highlights the need for conservation measures for these species. Despite three endemic species being listed in the Data Deficient (DD) category, this does not imply that they are free from threats. These results reflect the exceedingly small botanical collections in the region, and difficulties in the identification and taxonomic classification of these species create uncertainties. Nevertheless, threats such as climate change and increased human activity on the continent are already affecting byofloristic diversity. Therefore, it is essential to better understand the current distribution and abundance of these species to provide proper legislative protection and guide the implementation of conservation programs and protected areas. This study stands for the first investigation into the extinction risk of Antarctic plant species.

788

Assessing aerial biodiversity over Keller Peninsula, King George Island, maritime Antarctic, using DNA metabarcoding

Dr Paulo Camara^1,2, Dr Michael Stech³, Dr Peter Convey⁴, DR Tina Šantl-Temkiv⁵, Msc Fabio Bones², Dr Fabyano Lopes⁶, Dr Luiz Rodrigues⁷, Dr Micheline Silva¹, Dr Luiz Rosa⁸

¹Universidade de Brasilia, Brasilia, Brazil. ²Universidade Federal de Santa Catarina, Florianopolis, Brazil. ³Naturalis Biodiversity Center, Leiden, Netherlands. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Aarhus University, Aarhus, Denmark. ⁶Universidade Federal do Tocantins, Porto Nacional, Brazil. ⁷Museu Nacional, Rio de Janeiro, Brazil. ⁸Universidade Federal de Minas Gerais, Belo Horizonte, Brazil

Abstract

Antarctic ice-free areas are dominated by wind dispersed organisms. However, which organisms arrive and circulate in Antarctica, and how, remains poorly understood. Due to its proximity to South America and less extreme conditions, the South Shetland Islands are likely to receive higher diaspore numbers. One possible consequence of climate change is that newcomers will be able to colonize ice-free areas, altering community composition and impacting the native biota. We used DNA metabarcoding to identify non-fungal eukaryotic DNA present in the air that potentially reach and circulate in Antarctica. Air was sampled near the Brazilian Station on King George Island, between December 2019 and January 2020. Sequences representing a total of 35 taxa from 10 phyla and three kingdoms were assigned: Chromista (Ciliophora, Cercozoa, Haptophyta and Ochrophyta), Plantae (Chlorophyta, Bryophyta and Magnoliophyta) and Animalia (Mollusca, Arthropoda and Chordata). The most diverse group were the plants (26 taxa), followed by Chromista (6 taxa). The most abundant sequences represented the green algae Chlamydomonas nivalis. The two angiosperm sequences represent exotic taxa, Folsomia is also exotic and recorded only from Deception Island. Metabarcoding revealed the presence of previously undocumented airborne diversity, suggesting that the Antarctic airspora includes propagules of both local and distant origin.

789

Understanding adverse meteorological phenomena for aviation on Marambio Island, Antarctica, through special observations and simulations of the operational WRF model of the Colombian Air Force.

Mauricio Jiménez García¹, Álvaro Rafael Martínez Mancera¹, Kevin Alexander Chicaeme Ordoñez², Julián Pantoja², Walter Martinez², Nykolay Yanquen², Juan J. Henao³, John F. Mejia³, Noemí Troche⁴

¹Air Navigation Department, Colombian Air Force, Bogotá, Colombia. ²Fuerza Aérea Colombiana, Bogotá, Colombia. ³Division of Atmospheric Sciences, Desert Research Institute, Reno, USA. ⁴Servicio Meteorológico Nacional, Buenos Aires, Argentina

Abstract

For this research, the occurrence of dangerous meteorological events for aviation is observed, such as fog and extreme winds of the southern summer on Marambio Island, the Argentine Air and Research Base on the Antarctic Peninsula, through surface observations, special measurements in altitude and simulations of the WRF model, with the operational capabilities of the Colombian Air Force (FAC), with a spatial resolution of 9 km, using the initial and boundary conditions of the Global Forecast (GFS). The observations were reflected in two research campaigns, coordinated by the FAC, with the support of the Colombian Antarctic Program and the Argentine Antarctic Joint Command.

In these campaigns, particular meteorological events that affected air operations were observed, their synoptic conditions were analyzed, the first campaign was carried out from February 3 to 21, 2023 and the second from February 11 to March 3, 2024.

The main objective of this research is to examine the performance capability of the FAC operational forecast model in the short term (24 hours) and understand the weather patterns that aid operational forecasting. Initially, the phenomena of interest for the analysis will be determined, defining climatic and synoptic patterns, for subsequent evaluation of the model based on the data captured in the campaign.

790

Updates of the International Bathymetric Chart of the Southern Ocean (IBCSO)

Mr. Patrick Schwarzbach, Mr. Sacha Viquerat, Mrs. Natalie Cornish, Mr. Simon Dreutter, Mrs. Yvonne Schulze Tenberge, Mrs. Tea Isler, Dr. Boris Dorschel

Alfred Wegener Institute, Bremerhaven, Germany

Abstract

IBCSO v2.0 is the most comprehensive bathymetric chart, covering the area of the Southern Ocean, the South Atlantic, South Pacific and South Indian Ocean south of 50°S.

IBCSO v2 was published in June 2022 containing 25 billion data points from 1500 datasets from more than 88 institutions and institutes from 22 countries. The resolution is 500 m × 500 m in IBCSO Polar Stereographic projection (EPSG: 9354). In IBCSO v2 approximately 25% of the seabed are constrained by soundings. This means that less than a quarter of seabed south of 50°S is actually mapped, while more than three quarters of the seabed are constrained by satellite derived predicted bathymetry. Here, we would like to give an update on the latest data input and technical enhancements since the release of IBCSO v2 and encourage everybody to engage with the IBSCO Project to help make the invisible seabed visible.

791

Three-Year Observations of Ozone Columns over Polar Vortex Edge Area above West Antarctica

Professor Yuhan Luo¹, Doctor Qidi Li^1,2, Doctor Yuanyuan Qian³

¹Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China. ²University of Science and Technology of China, Hefei, China. ³Department of Optoelectronic Engineering, School of Microelectronics & Data Science, Anhui University of Technology, Ma’an Shan, China

Abstract

Ozone vertical column densities (VCDs) were retrieved by Zenith Scattered Light-Differential Optical Absorption Spectroscopy (ZSL-DOAS) from January 2017 to February 2020 over Fildes Peninsula, West Antarctica (62.22°S, 58.96°W). Each year, ozone VCDs started to decline around July with a comparable gradient around 1.4 Dobson Units (DU) per day, then dropped to their lowest levels in September and October, when ozone holes appeared (less than 220 DU). Daily mean values of retrieved ozone VCDs were compared with Ozone Monitoring Instrument (OMI) and Global Ozone Monitoring Experiment 2 (GOME-2) satellite observations and the Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis dataset, with correlation coefficients (R² ) of 0.86, 0.94, and 0.90, respectively. To better understand the causes of ozone depletion, the retrieved ozone VCDs, temperature, and potential vorticity (PV) at certain altitudes were analyzed. The profiles of ozone and PV were positively correlated during their fluctuations, which indicates that the polar vortex has a strong influence on stratospheric ozone depletion during Antarctic spring. Located at the edge of polar vortex, the observed data will validate modelled ozone concentrations in this region and contribute to better understanding of ozone recovery and stratosphere-troposphere exchange over the polar vortex edge area in the future.

793

Main contributions and challenges of the Colombian project, Marine Scientific Research for Maritime Safety in Antarctica (Iceman), between 2014-2024

PhD Diana María Quintana-Saavedra

General Maritime Directorate, Bogotá, Colombia

Abstract

Antarctica continues to be recognized for the development of research necessary to understand the global environment and is subject to different legal regulations aimed at science and peace, in terms of environmental protection, species protection, access and use. of resources (Roser, 2015). To achieve balance in these components, and allow their adequate development, the management of Antarctica is guided by the Antarctic Treaty System, where different countries develop their research collaboratively.

With this framework, Colombia, through the General Maritime Directorate-DIMAR, a member entity of the Colombian Antarctic Program, leads its research on the Antarctic continent, within the framework of the Marine Scientific Research for Maritime Safety in Antarctica (Iceman) project. Through the project, bathymetric information has been generated for the Gerlache Strait, in collaboration with Chile and the United Kingdom (Molares, R 2015; Gutiérrez, 2018).

Likewise, contributions have been made in the study of the oceanographic characteristics of the Gerlache Strait, the Drake Passage and its connection with the Pacific Ocean (Torres-Parra 2020). In addition, studies have been carried out on the quality of water and sediments in the fjords that make up large bays (Duarte, Eckener, Frei -Recess-, Wilhelmina -small unnamed central bay- and Paraíso-Paradise-) (Rodrigo;C, 2021 ); Identification of phytoplankton blooms (Cañón-Páez, 2021).

In terms of open data, Dimar has migrated the information associated with the expeditions to the Spatial Data Infrastructure and the Colombia Data Center, where the different results achieved are expanded and detailed. Finally, the expedition carried out last southern summer 2023-2024 stands out, with a Colombian vessel, specially built to navigate in polar environments, in the past the ARC Simón Bolívar.

Therefore, it is important to present the main results mentioned, in order to contribute to the strengthening of scientific research on the Antarctic continent.

795

Life in ruins, DNA metabarcoding contributes to the history of Whalers Bay wooden structures at Deception Island, South Shetland Islands

Dr Paulo Camara^1,2, Dr Fabyano Lopes³, Msc Fabio Bones², Dr Micheline Silva¹, Dr Peter Convey⁴, Msc Lauren Drumond⁵, Dr Luiz Rosa⁵

Abstract

Deception Island is an Antarctica Specially Managed Area and houses historically important sites, like the remains of historic wooden buildings. The impacts of fungal communities on wood in polar historic sites have been investigated but little is known of other eukaryote groups. In the current study we used high throughput sequencing to investigate the diversity of non-fungal eukaryotic organisms present in wood samples from Whalers Bay. Four sites were sampled and DNA sequences representing three Kingdoms (Chromista, Protozoa and Viridiplantae) and four Phyla (Ciliophora, Perclozoa, Chlorophyta and Magnoliophyta) were identified, representing a total of 43 taxa. Biscoe House Annex hosted the richest diversity with 20 taxa, followed by the whaling boat, Biscoe House and the Hunting Lodge, with 16, 15 and 12 taxa, respectively. The most frequently detected sequences were assigned to the ciliate group Sporadotrichida, some of which are known to play a role in cellulose degradation. Among the Chlorophyta, sequences detected included common taxa previously recorded, but the flowering plant data represented only exotic taxa, likely associated with human activity or airborne transfer. The use of HTS provided valuable data on communities associated with anthropogenically-sourced and now decaying wood in Antarctica.

802

Changes of inflammatory biomarker serum amyloid A in a 7-week summer camp in Antarctica

Dra. Michele M Moraes¹, Dr. Leandro Borges², Dr. Thiago T Mendes^3,4,5, Ms. Mateus Rumão⁵, Ms. Nathalia Garcia⁴, Dra. Elaine Hatanaka², Dra. Rosa Arantes¹

¹Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ²Interdisciplinary Program in Health Sciences, Universidade Cruzeiro do Sul, São Paulo, Brazil. ³Postgraduate Program in Medicine and Health, Universidade Federal da Bahia, Salvador, Brazil. ⁴Postgraduate Program Physical Education, Universidade Federal do Maranhão, São Luis, Brazil. ⁵Postgraduate Program in Science and Health, Universidade Federal do Maranhão, São Luis, Brazil

Abstract

Isolated, confined, and extreme (ICE) conditions in Antarctica can influence the immune system and inflammatory responses, especially considering the potentially stressful ICE conditions and consumption of processed and ultra-processed foods. In this context, clinical biomarkers can contribute to understanding the physiological responses in extreme conditions. We evaluated the inflammatory biomarkers serum amyloid A (SAA), transforming growth factor-beta (TGF-β), and fatty acid-binding protein 2 (FABP2). Seven expeditioners took part in a 7-week Antarctic summer camp (Nelson Island; S 53.178533°/O 70.899750° S 53.178533°/O 70.899750°) and were evaluated at Pre-Camp (i.e., at the beginning of the ship travel), Camp-Initial (i.e., 4th and 5th day in camp), Camp-Final (i.e., 45th–46th day), and the Post-Camp (on the ship) (Ethics Committee protocol number: UFMG 19092819.8.0000.5149/3.744.162). One-way RM ANOVA was applied. The α level was set at 0.05. Cohen's d-effect size (ES) for ANOVAs was also calculated. There were no differences for TGF-β (F = 0.408, p = 0.750; ES = 0.4) and FABP2 (F = 0.878; p = 0.472; ES = 0.7); however, camping in Antarctica induced a bi-phasic change in SAA, with an increase at Camp-Initial (F = 3.566; p = 0.042, ES = 1.6), followed by a return to baseline levels. The present data indicate a transient acute inflammation that does not imply a chronic inflammation condition during a long-term camp.

Funded by CNPq/MCTI/CAPES/FNDCT/PROANTAR: [442645/2018-0] and [440932/2023-8]; and CNPq/MCTI [408740/2023-0].

805

The role of Early Career Scientists in Promoting Diversity, Equity and Inclusion (DEI): the APECS DEI Project Group as example

Rose Leeger^1,2, Inge Deschepper^1,3, Mariama C. Dryák-Vallies^1,2,4, Meghan Schaberg^1,5, José P. Queirós^1,6,7, Elaine Runge^1,8

¹Association of Polar Early Career Scientists - DEI Project Group, Tromsø, Norway. ²The University of Colorado-Boulder, Boulder, USA. ³Université Laval, Department of Biology, Quebec, Canada. ⁴Polar Science Early Career Community Office (PSECCO), Boulder, USA. ⁵Colorado State University, Fort Collins, USA. ⁶University of Coimbra, Marine and Environmental Sciences Centre (MARE)/ Aquatic Research Network (ARNET), Department of Life Sciences, Coimbra, Portugal. ⁷British Antarctic Survey (BAS), Natural Environmental Research Council (NERC), Cambridge, United Kingdom. ⁸Danish Hydrological Institute, Hørsholm, Denmark

Abstract

The Association of Polar Early Career Scientists (APECS) Diversity, Equity, and Inclusion (DEI) Project Group aims to work towards ensuring that one’s identity is not a barrier to success in polar science. DEI initiatives benefit polar research overall and can be strengthened by collaborations with diverse participants (diversity), creating a welcoming environment (equity), and ensuring all resources and materials are accessible (inclusion). APECS works towards these initiatives through partnerships with other project groups to create webinars, educational workshops, and strengthen intersectional and interdisciplinary networking efforts that help incorporate DEI into art, community development, and mental health discussions. Our current goals work towards creating a shared mentorship database, keeping an APECS-hosted DEI resource repository up-to-date and usable by the entire polar science community, and increasing international collaborations-especially with countries that have been under-represented within the polar fields. Our most recent initiative focused on hosting two DEI-focused workshops in partnership with the Scientific Committee for Antarctic Research (SCAR), run by an external professional facilitator, that covered methods for eroding biases and practicing bystander intervention techniques in polar science or research environments. These shared workshops identified and reduced barriers towards early career researchers and worked towards building equitable practices within the polar research community to help foster a safe environment for all.

809

Changes in the metabolic pathways of prokaryotic communities associated with a phytoplankton bloom during the spring-summer transition in Maxwell Bay (Northern Antarctic Peninsula)

Camila Marín Arias¹, Dra. Mireia Mestre Martín^2,3,4, Dr. Sergio Guajardo-Leiva^5,6, Dr. Eduardo Castro-Nallar^5,6, MSc. Diego Hernández-Cerón¹, Dr. Juan Höfer^1,3

¹Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. ²National Museum of Natural Sciences, Madrid, Spain. ³Centro IDEAL, Universidad Austral de Chile, Valdivia, Chile. ⁴Centro COPAS-Coastal, Universidad de Concepción, Concepción, Chile. ⁵Departamento de Microbiología, Universidad de Talca, Talca, Chile. ⁶Centro de Ecología Integrativa, Universidad de Talca, Talca, Chile

Abstract

Throughout the year Antarctic coastal ecosystems experience strong variations in solar radiation, glacier melting and sea ice extent, due to the extreme seasonality. In summer, the flow of glacial meltwater into the ocean promotes water column stratification that, together with the increased solar radiation and slower winds, enable phytoplankton growth and bloom development. Those blooms alter the quality and quantity of organic matter that, in turn, affects the composition of the microbial community and its metabolic activity. In this study, a time series station was sampled 13 times between November 2021 and January 2022 near Collins Glacier in Maxwell Bay (King George Island, Northern Antarctic Peninsula). Samples included prokaryotic metatransctiptomes and environmental data. Throughout this period, in surface waters we observed a decrease in salinity (34.14 PSU to 34.09 PSU) and an increase in temperature (0.55°C to 1.45°C), oxygen (8.27 mg L^-1 to 9.01 mg L^-1), chlorophyll-a (1.09 mg m^-3 to 7.54 mg m^-3), and prokaryotic abundance (426,993 cells ml^-1 to 1,052,240 cells ml^-1), indicating the spring-summer succession from low to high productivity. Regarding prokaryotic expressed functions, at the beginning of the time series we detected higher levels of metabolic pathways related to the DMSP cycle, siderophore expression and vitamin B12 synthesis. In contrast, as the phytoplankton bloom developed, the expression of pathways related to carbon fixation, and genes related to photosystem II and the enzyme RuBisCO increased. These results provide detailed insight into the microbial functional response to seasonal changes in the Southern Ocean and its links with phytoplankton blooms.

811

Preliminary assessment of sponge assemblages from Antarctic hydrothermal systems: Deception Island and Orca Seamount

Alvaro Arteaga¹, Victor Seixas², Aldo Indacochea¹, Natalia Venturini³, Luis Cerpa⁴, Báslavi Cóndor-Luján¹

¹Universidad Científica del Sur, Facultad de Ciencias Veterinarias y Biológicas, Carrera de Biología Marina, Lima, Peru. ²Universidade Federal Fluminense, Departamento de Biologia Marinha, Instituto de Biologia, Rio de Janeiro, Brazil. ³Universidad de la República, Facultad de Ciencias, IECA, Oceanografía y Ecología Marina, Montevideo, Uruguay. ⁴Instituto Geológico, Minero y Metalúrgico, INGEMMET, Lima, Peru

Abstract

Hydrothermal vents are unique marine ecosystems that harbor diverse communities, where complex and extensive interactions are driven by physicochemical conditions. Sponges are recognized as a crucial benthic component that plays a key ecological role in Antarctic ecosystems. Hydrothermal sites in the Bransfield Strait provide an interesting scene to explore deep Southern Ocean sponges in relation to abiotic factors. The aim of this study is to assess the sponge species composition in relation to abiotic factors in two different sites located close to hydrothermal systems in the Bransfield Strait, Antarctic Peninsula, during the austral summer of 2019 – 2020. The material was obtained during the Peruvian Scientific Expedition to Antarctica (ANTAR XXVII) on board of the Peruvian oceanographic vessel BAP Carrasco. The two sampling areas of hydrothermal activity were Deception Island and Orca Seamount. A total of five rock dredge transects were considered, from where sponges were collected. Rock and bottom water samples were also collected for abiotic analyses. Sponge species composition was determined in each transect, whereas six abiotic parameters were considered: minimum depth, maximum depth, temperature, salinity, silicon dioxide and calcium oxide. A Detrended Correspondence Analysis was performed to assess the relation between abiotic variables and species composition. Among the 13 specimens collected, 11 different species were identified. Orca Seamount presented greater richness (n=6) than Deception Island (n=5). None of the tested abiotic variables were significantly influencing the species composition. Since eight species are known for Deception Island and none for Orca Seamount, this study highlights the increase to 13 and six species, respectively. More studies are necessary to better understand how abiotic factors can influence hydrothermal Antarctic sponges, making it possible to observe patterns or ecological processes along the time.

Keywords: Antarctic sponges, Hydrothermal systems, Peruvian Antarctic Expedition, Richness

814

Diversity and abundance of prokaryotes in Antarctica: the effect of oceanography in the Bransfield Strait.

Camila Marín Arias¹, Dr. Juan Höfer^1,2, Dr Ramiro Logares Haurié³, Dra. Beatriz Díez^4,5,6, Dra. Camila Fernández^7,8, Dr. Bjørn Krafft⁹, Dra. Mireia Mestre Martín^10,2,11

¹Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. ²Centro IDEAL, Universidad Austral de Chile, Valdivia, Chile. ³Institute of Marine Sciences, Barcelona, Spain. ⁴Biological Sciences Faculty, Pontificia Universidad Católica de Chile, Santiago, Chile. ⁵Millennium Institute Center for Genome Regulation, Santiago, Chile. ⁶Center for Climate and Resilience Research, Santiago, Chile. ⁷Universidad de Concepción, Concepción, Chile. ⁸Laboratory of Microbial Oceanography, Banyuls sur Mer, France. ⁹Institute of Marine Research, Bergen, Norway. ¹⁰National Museum of Natural Sciences, Madrid, Spain. ¹¹Centro COPAS-Coastal, Universidad de Concepción, Concepción, Chile

Abstract

Microorganisms fulfill essential roles in marine ecosystems and their study is essential to understand their functioning. Despite its importance, in Antarctic waters, and particularly in the Bransfield Strait, there is little information about it. This study describes the spatial patterns of abundance and diversity of free-living and particle-associated prokaryotic communities (Archaea and Bacteria) in the Bransfield Strait. Oceanographic conditions were recorded at 13 stations, and in 7 of them the prokaryote community was analyzed at depths between 5 and 1000m. Each sample was separated into 3 size fractions, being able to differentiate free-living prokaryotes (0.2-3μm) from those associated with particles (3-20μm; 20-200μm). Prokaryotic diversity was analyzed by 16S rRNA gene sequencing (75 samples), and abundance was analyzed by flow cytometry. Diversity and abundance varied with depth: a greater abundance of prokaryotes was found in surface waters, and a greater diversity in deep waters. Similar diversity was observed in the three fractions when high-level taxa were considered (Phylum, Class), but significant differences were observed when considering low-level taxa (Genera and Species). The variables that most explain the composition of the community are depth (~20%), followed by lifestyle (~16%). The largest number of indicator species was found in deep water, followed by the free-living fraction. The composition of the surface water community is positively related to higher temperature and oxygen concentration, while deep communities were related to higher salinity. Specific prokaryotic communities were observed based on depth, ecoregion, water mass, and distance from Deception Island. These results show that there are prokaryotic communities that are structured according to the variables considered, and that the deep waters of the Bransfield Strait represent a reservoir of microbial diversity in this Antarctic area.

819

EXHIBITION ON ANTARCTIC CAMPS AT THE UNIVERSITY OF BUENOS AIRES, 15 YEARS OF TRAJECTORY

Dr. Andrea Concheyro^1,2, Dr. JUAN MANUEL LIRIO¹, Dr. Cecilia Amenábar^1,2, Dr. Flavia Salani³

¹IAA. Instituto Antártico Argentino. Cs. Tierra, Buenos Aires, Argentina. ²IDEAN-CONICET-UBA, Buenos Aires, Argentina. ³IGEBA-CONICET, Buenos Aires, Argentina

Abstract

The purpose of this contribution is to present the Antarctic outreach activities, carried out systematically for 15 years by geoscientists, researchers of the Antarctic Institute of Argentina and teachers of the University of Buenos Aires in the exhibition of the” Earth Science Week at the University of Buenos Aires”. Since the first year of the exhibition, a real geological and palaeontological exploratory camp was set up, recreating the conditions of the terrain, with the assembly of the sleeping tents and laboratories, and also the natural environment with the polar clothing of the scientists, backpacks, ropes, sleds, taxidermied penguins and logistical accessories. Subsequently, hand-sampled rocks and petrographic sections were added for observation, as well as Mesozoic and Cenozoic fossils collected on expeditions in the James Ross Basin, northeast Antarctic peninsula. Maps, geological sheets and posters pointing out the lines of research in geology and palaeontology were considered. The target audience included university and high school students, as well as children from the kindergarten run by the university, families of university staff and passers-by. The experience was enriching, very successful, and as time went by, some geology, and palaeontology students confessed to us that as a result of interaction with scientists and seeing our enthusiasm, were triggers for studying geology and palaeontology at the University of Buenos Aires, and some of them are nowadays protagonists of Antarctic scientific life.

821

Navigating Antarctic currents: Fine-scale population genomics of buoyant kelp around the sub-Antarctic islands and New Zealand offers insights into kelp dispersion to Antarctica

Mx Xiaoyue P. Liu¹, Dr Narissa Bax², Dr Grant A. Duffy¹, Prof Ceridwen I. Fraser¹

¹University of Otago, Dunedin, New Zealand. ²South Atlantic Environmental Research Institute, Stanley, Falkland Islands (Malvinas)

Abstract

Southern bull kelp (Durvillaea antarctica) and giant kelp (Macrocystis pyrifera), both renowned for their remarkable buoyancy, have successfully traversed the challenging waters of the Southern Ocean to reach Antarctica. Previous high-resolution genomic analyses have yielded valuable insights into the origins of bull kelp specimens found along Antarctic coasts. However, similar analyses have not been applied to identify source populations of giant kelp specimens, while data on fine-scale variations between populations of both kelp species remains scarce, hindering our ability to confidently pinpoint their origins. In this study, we focused on characterising phylogeographical variations of both kelp species around the sub-Antarctic islands and the New Zealand coasts. We aim to use phylogenomic analysis to assign regional sources and provide fine-scale assignments down to specific parts of islands. We anticipate high spatial variation yet expecting population connectivity within regions. Such information could not only enhance our understanding of regional variation and biogeographic processes of kelp populations around the Southern Ocean, but also contribute to refining models of kelp dispersal to Antarctica, which may pose potential invasion risks in the future. This research is pivotal for understanding how connectivity dynamics, both among the Southern Ocean and between Antarctica and other landmasses, is impacted by the changing climate.

822

Bioinformatic evidence of multiple secretion systems in host-related bacteria from Antarctic sponges

Dr(c). Patricio Flores-Herrera¹, Sr. Philippe Loustau¹, Dra. Nicole Trefault^1,2,3

¹GEMA Center for Genomics, Ecology & Environment, Facultad de Ciencias, Universidad Mayor, Santiago, Chile. ²Millenium Nucleus in Marine Agronomy of Seaweed Holobionts (MASH), Santiago, Chile. ³FONDAP Center IDEAL- Dynamics of High Latitude Marine Ecosystem, Santiago, Chile

Abstract

Bacteria in Antarctic sponges compose a highly complex and diverse community. These bacteria, along with their host, make up what we call holobiont. To form a close relationship, bacteria must export different effectors to the host that allow them to establish a commensal, mutualistic or parasitic lifestyle.

In this work, we explore the presence of secretion systems, complex molecular machineries that export different molecules, such as DNA and proteins, to the extracellular space and into the host cells, that play a significant role in the establishment of symbiosis. We analyze 37 metagenomic assembled genomes (MAGs) and several bacterial strains isolated from Antarctic sponges collected from the Western Antarctic Peninsula.

Despite limited knowledge of the genetic organization of secretion systems in sponge holobionts, metagenomic assembled genomes (MAGs) from Antarctic sponge microbiomes show seven types of secretion systems, all complete: secretion system type 1, 2, 3, 4, 5, 6, and 9. Moreover, bacterial strains isolated from Antarctic sponges also display these complete secretion systems. Bioinformatic predictions indicate that different effectors such as cold shock proteins, cysteinyl-tRNA synthetase, sigma factor sigB regulation protein rsbU, inorganic phosphate transporter, among others are present in strains of Cellulophaga sp. and Pseudoalteromonas sp. isolated bacteria.

Overall, these results give us positive evidence of the functionality of these secretion systems as a possible symbiotic mechanism that help the bacteria to evade the host immune response, establish a connection with the host, and further assist the host to overcome and adapt to the extreme cold conditions and environmental stress from Antarctica.

Exploring the diversity and function of these secretion systems is crucial for understanding the mechanisms that enable symbiotic relationships between bacteria and their sponge hosts in these pristine ecosystems.

Acknowledgments:

ANID 21190286-doctoral-fellowship

INACH DG_12-20

and Fondecyt Grant N°1230758.

823

Evaluating last millennium Antarctic climate trends in paleoclimate models

Vincent Charnay¹, Dan Lowry^1,2, Liz Keller^3,2, Abha Sood⁴

¹Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. ²GNS science, Wellington, New Zealand. ³Antarctic research Centre, Victoria University of Wellington, Wellington, New Zealand. ⁴NIWA, Wellington, New Zealand

Abstract

Surface mass balance (SMB) of the Antarctic Ice Sheet (AIS) is an important contributor to global sea level change. SMB is expected to increase in response to atmospheric warming but future projections of ice sheet and atmospheric dynamics in response to different climate scenarios are subject to deep uncertainties. One way to examine this question is by looking at past climate, as we believe a better understanding of the processes controlling past variability in AIS SMB will improve our ability to predict future SMB under a changing climate. In this context, there is growing evidence from ice core records for large regional differences in SMB trends over the Last Millennium (LM, 850-1850 CE). The actual drivers for such regional variations remain uncertain, demonstrating the need for a regionally focused study. Regional Climate Models (RCMs) can be used to dynamically downscale SMB components over the ice sheet using large-scale forcing at their boundaries from General Circulation Model (GCM) fields to estimate ice sheet SMB at higher spatial resolution. The instrumental record provides only a limited dataset against which to assess model performance. Hence, there is a need for GCMs to be validated over long timescales to assess if they capture long-term regional variations. Using the broad spatial coverage of LM Antarctic proxy records, we perform an evaluation of the GCMs’ skill in simulating regional climate changes. We evaluate all available Paleoclimate Modelling Intercomparison Project past1000 models using a multi-parameter scoring method that considers different climate regions of Antarctica. Our results show that MPI-ESM-P is the best scoring model, no models perform equally well for all parameters, and many models show snow accumulation regional biases. This preliminary work informs planned high-resolution LM experiments aimed at understanding large-scale drivers of regional Antarctic SMB variations.

824

Understanding benthic dynamics in the continental shelf off the Antarctic Peninsula using biological trait analysis.

Paula Fragueiro Sabaini¹, Dr. David K.A. Barnes², Dr. Christoph Held³, Dr. Enrique Isla⁴

¹University of the Basque Country (UPV/EHU), Bilbao, Spain. ²British Antarctic Survey (BAS), Cambridge, United Kingdom. ³Alfred-Wegener-Institut (AWI), Bremerhaven, Germany. ⁴Instituto de Ciencias del Mar (ICM) – CSIC, Barcelona, Spain

Abstract

The Antarctic Peninsula (AP) is renowned for its rich and productive continental shelf biota while it is also one of the fastest-changing regions globally, especially along its fjord coast due to ongoing anthropogenic climate forcing. Among other consequences, impacts on spatial distribution and community composition of the regional pelagic and benthic communities may result in cascading effects along the entire ecosystem. Understanding the impacts of physical drivers on benthic communities requires consideration of the biological traits of local fauna, e.g. feeding mechanisms, mobility and habitat preferences. Functional methods such as Biological traits analysis (BTA) can elucidate links between biodiversity and ecosystem functioning in benthic communities, revealing temporal and spatial variations to environmental factors such as depth and seafloor substrate, temperature and melt-water input.

The working hypothesis is that benthic fjord habitats and their associated benthic assemblages differ from an open shelf area considering the varying responses to environmental gradients and conditions. Using perpendicular seafloor photography, this study compares benthic assemblages in two distinct regions: the inner shelf, situated in a fjord under melt-water influence, to the south of the South Shetland Islands, and the outer shelf, influenced by the Transitional Zonal Water with Bellingshausen Sea and Circumpolar Deep Water. These regions differ in depth, topography, orientation, and exposure to tidal currents and iceberg scouring.

Preliminary findings indicated a higher abundance of fjord benthic assemblages compared to the outer shelf, with suspension feeders prevailing in both regions. Despite diversity variations among stations, models suggest turbidity and rugosity as potential negative diversity predictors within the fjord. Conversely, substrate and oceanographic factors, especially temperature and salinity, appear influential on the outer shelf's diversity patterns. These results prompt future research lines exploring how particular traits are linked to distinct environmental conditions, especially in the volatile Antarctic Peninsula region.

825

Assessing ERA5 and MERRA2 Reanalysis data Accuracy in Antarctic Upper Air Observations using Radiosonde data of Bharati station

Mr Vivek Kumar, Dr Vijay Kumar Soni

Polar Meteorological Research Division (PMRD), India Meteorological Department (IMD), Ministry of Earth Sciences, New Delhi, India

Abstract

Introduction

Global reanalysis datasets like ERA5 and MERRA2 are vital for climate research, offering continuous records of weather and climate variables. This study evaluates the accuracy of these datasets for upper-air observations in Antarctica by comparing them with observed data from 2016 to 2022. The Antarctic environment presents unique challenges due to its extreme weather conditions and complex ocean currents. Accurate modeling of the Antarctic climate is crucial for understanding the impacts of climate change. To assess ERA5 and MERRA2 over Antarctica, real observations from Bharati, an Indian research base, from 2016 to 2021 were utilized.

Methodology and Significance

This analysis is based on the two most recent reanalysis datasets, MERRA2 and ERA5. The study evaluates the reliability of these datasets by statistically analyzing real observations from Bharati with the reanalysis data. The radiosonde data(2016-21) provide high-resolution profiles of atmospheric parameters. By comparing these observations with the reanalysis products, the study offers insights into the accuracy of the datasets in the Antarctic environment. The results of this study are particularly relevant given the increasing vulnerability of Antarctica to climate change and its potential impacts on global sea levels and ocean currents.

Results and Discussion

Preliminary analysis reveals significant differences between radiosonde observations and reanalysis products in the Antarctic upper air. MERRA2 exhibits strong correlations (0.99 for temperature, 0.97 for wind) with radiosonde data, whereas ERA5 demonstrates moderate correlations (0.43 for temperature, 0.11 for wind). While both datasets perform well near the surface, ERA5's quality declines at higher altitudes, while MERRA2 remains consistent. MERRA2 maintains uniform performance across all seasons, while ERA5 reliable particularly in Autumn.

MERRA2 reanalysis datasets provide reliable upper-air observations in Antarctica, with high agreement with observed data. Further studies are underway to assess reanalysis datasets across more Antarctic stations.

826

The Interaction of Ice Tongues and Land-fast Sea Ice – New Insights for Stability from Satellite Observation and Modelling.

Phd Rodrigo Gomez-Fell^1,2, Professor Wolfgang Rack^3,2, PhD Oliver J. Marsh⁴, Associated Professor Heather Purdie²

¹Waterways Centre, School of Earth and Environment, University of Canterbury, Christchurch, New Zealand. ²School of Earth and Environment, University of Canterbury, Christchurch, New Zealand. ³Gateway Antarctica, School of Earth and Environment, University of Canterbury, Christchurch, New Zealand. ⁴British Antarctic Survey, Cambridge, United Kingdom

Abstract

Antarctic ice tongues, the floating end of glaciers, play an important role in modulating local ice-ocean interactions and climate dynamics. This study focuses on the mechanics of ice tongues and their interplay with currents and land-fast sea ice. We integrate synthetic aperture radar (SAR) interferometry data with analytical modelling to illuminate the complexities of ice tongue behaviour.

Our observations reveal a dynamic interplay between ice tongues and their surrounding environment. Fast ice exerts a stabilising influence on ice tongues by dampening lateral bending and reducing stress from ocean currents. An analysis of three years of interferometric data shows that fast ice presence correlates with diminished lateral flexure and decreased stress on the ice tongue. Contrarily, periods without fast ice exhibit heightened lateral displacement and increased vulnerability to fracturing.

Analytical modelling based on beam theory provides valuable insights into the mechanical responses of ice tongues to environmental forcings. We observe significant correlations between ice tongue flexure and tidal currents, which are particularly evident when fast ice is absent. Our study underscores the protective role of fast ice in stabilising ice tongues and highlights the potential implications of future changes in fast ice extent on ice tongue stability.

Overall, this research enhances our understanding of the intricate interactions between Antarctic ice tongues and their surrounding environment, contributing to better predictions of ice shelf stability in a changing climate.

827

Enhancing human and environmental well-being in the polar regions: The WWRP’s Polar Coupled Analysis and Prediction for Services (PCAPS) project

Dr Daniela Liggett¹, Dr Jørn Kristiansen², Dr Dina Abdel-Fattah², Dr David Bromwich³, Dr Philip Browne⁴, Dr Nico Caltabiano⁵, Dr Barbara Casati⁶, Dr Christopher Davis⁷, Dr Clare Eayrs⁸, Ms Victoria Heinrich^9,10, Dr Jelmer Jeuring¹¹, Dr Machiel Lamers¹², Dr Gita Ljubicic¹³, Dr Linus Magnusson¹⁴, Dr Hanne Nielsen⁹, Dr Andrew Orr¹⁵, Dr Paola Rodriguez Imazio¹⁶, Dr Gunilla Svensson¹⁷, Mr Jeff Wilson¹⁸

¹University of Canterbury, Christchurch, New Zealand. ²Norwegian Meteorological Institute, Oslo, Norway. ³Ohio State University, Columbus, USA. ⁴European Centre for Medium-Range Weather Forecasts, Reading, USA. ⁵World Meteorological Organization, Geneva, Switzerland. ⁶Meteorological Research Division, Environment and Climate Change Canada, Dorval, Canada. ⁷NSF National Center for Atmospheric Research, Boulder, USA. ⁸Korea Polar Research Institute, Incheon, Korea, Republic of. ⁹University of Tasmania, Hobart, Australia. ¹⁰Bureau of Meteorology, Hobart, Australia. ¹¹Norwegian Meteorological Institute, Bergen, Norway. ¹²Wageningen University, Wageningen, Netherlands. ¹³McMaster University, Hamilton, Canada. ¹⁴European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom. ¹⁵British Antarctic Survey, Cambridge, United Kingdom. ¹⁶National Weather Service, Buenos Aires, Argentina. ¹⁷Stockholm University, Stockholm, Sweden. ¹⁸Norwegian Meteorological Institute, Anglesea, Australia

Abstract

The Polar Coupled Analysis and Prediction for Services (PCAPS) project was initiated in 2024 by the World Weather Research Programme (WWRP) under the World Meteorological Organization (WMO) to enhance environmental forecasting in the Antarctic and Arctic, thereby facilitating operational safety and enhancing human and environmental well-being. More specifically, PCAPS endeavours to improve the fidelity, actionability, and impactof environmental services in these extreme and rapidly changing polar environments.

In this presentation, we will discuss the five key objectives that PCAPS aims to achieve by the end of its envisioned 5-year lifetime:

PREDICT (providing more accurate and reliable analyses and predictions),
SERVICES (enhancing environmental services),
SUSTAINABILITY (enabling informed decision-making to enhance human safety and mitigate environmental risk),
PARTNERSHIPS (strengthening partnerships through trans-disciplinary coordination and cooperation), and
INCLUSIVITY (facilitating inclusivity and capacity development).

We will share the outcomes of an initial trans-disciplinary interactive expert elicitation that identified key research needs aligned with the aforementioned PCAPS objectives and that also brought to light operational, legal, political and environmental challenges. In particular, the elicitation identified challenges relating to conflicting spatio-temporal definitions with regard to forecasting obligations versus salient service provision.

Across the entire research- to operations- to services spectrum, we will also critically examine existing knowledge about pertinent user needs as well as gaps in current service capabilities, identifying future research, services and communication needs.

Our work thus far concludes that significant barriers to cross-sector and trans-disciplinary communication and collaboration in the environmental services space exist. While initiatives such as the WWRP Polar Prediction Project significantly developed capacity in polar forecasting and collaboration across the modelling and observations communities, challenges remain for providing inclusive and equitable environmental services. Our presentation will conclude by sharing a way forward to addressing these challenges.

828

Application of Colombian satellite capabilities for greenhouse gases estimation in Antarctica

Javier Méndez Gómez, Germán Sáenz Hernández, Jorge Rivera Castro

Aerospace Technologies Research and Development Center - Colombian Air Force, Cali - Valle del Cauca, Colombia

Abstract

Considering that one of the global scientific priorities on the Antarctic continent is the impact of climate change on the energy balance of the planet, the measurement and monitoring of greenhouse gases are tools for the development of strategies to mitigate the effects of this phenomenon, for this reason Colombia, through the Colombian Air Force, has used the capabilities of the payloads of the Earth observation satellite FACSAT-2 to estimate the concentration of greenhouse gases in Antarctica.

Using the capabilities of the spectrometer integrated as the second FACSAT-2 payload, it is possible to measure the concentration of anthropogenic emissions in the form of carbon dioxide (CO2) and part of the methane band (CH4). This is achieved by measuring radiation rates at specific wavelengths, relying primarily on the infrared radiation emitted into space, which can be recorded by the spectrometer on board FACSAT-2. This capability is complemented by the satellite's main payload, an eight-band multispectral camera, which allows the acquisition of geo-referenced images for fusion with the data generated by the spectrometer.

To map the spatial variation of greenhouse gases with known reflectance spectra, the interpretation of the measurements is based on information about the satellite location for precise geolocation of the spectrometer surface pixel, the application of a radiation transfer recovery algorithm and knowledge of surface cloud conditions and topography, with a nadir acquisition configuration of the spectrometer, it is possible to record the infrared radiation emitted to space by the Earth's surface and atmosphere.

In this way, Colombia will continue to make a significant contribution to one of the six scientific priorities set out in the document "Six Priorities for Antarctic Science", specifically to the first priority, which relates to defining the extent of changes in the Antarctic atmosphere and Southern Ocean.

836

Plio-Pleistocene paleoenvironmental reconstructions from the Pacific Sector of the Antarctic Circumpolar Current: Diatom and sediment geochemistry proxies from IODP 383 Site U1539

Meghan Duffy¹, Christina Riesselman¹, Oliver Esper², Vivian Sinnen², Lester Lembke-Jene²

¹University of Otago, Dunedin, New Zealand. ²Alfred Wegener Institute, Bremerhaven, Germany

Abstract

The Mid-Pleistocene Transition (MPT) marks a fundamental shift in Earth’s climate system from ~41 ky lower amplitude glacial cycles to higher amplitude ~100 ky cycles. The Antarctic Polar Front (APF), which maintains strong control on upwelling and productivity in the Southern Ocean, is known to migrate over time, with notable shifts during major climate transitions. Previous studies have identified changes in APF position and associated changes in the biological pump across the MPT, but data from the Pacific Sector of the Southern Ocean are sparse due to difficulty of access. Here, we present new diatom and geochemical records from IODP Site U1539, located at 56°09.0655′S°S in the Pacific Sector of the Antarctic Circumpolar Current (ACC). At Site U1539, a shift in the diatom assemblage across the MPT indicates a northward shift of the APF around 750 kya. The pre-MPT assemblage is dominated by Thalassiothrix antarctica mats (10.3-46.7%), transitioning to a more diverse assemblage post-MPT. The post-MPT assemblage notably records cyclicity in the relative abundance of Eucampia antarctica (0-11.1%), with peaks in abundance coinciding with glacial periods. Throughout the 1.4 Myr record, summer sea surface temperature (SSST) and weight % biogenic silica (wt.% BSi) vary cyclically with the global benthic oxygen isotope stack indicating sensitivity to glacial-interglacial change. Higher wt.% BSi and cooler SSSTs occur during glacials while lower wt.% BSi with warmer SSSTs coincide with interglacials. Siliceous productivity is notably low in marine isotope stage (MIS) 11, where the sediment is characterized by carbonate ooze. The diatom record at U1539 also contains isolated peaks in % Chaetoceros resting spores, most occurring during glacial-interglacial transitions with the highest abundance (53.6%) following MIS 31.

839

Study on the Mechanism of Core Breaking in Hydraulic Reverse Cycle Continuous Coring.

rusheng Wang, zhihao Cui

Jilin university, Changchun, China

Abstract

In the field of polar research, obtaining samples of subglacial bedrock at the bottom of the polar ice sheet is of great significance for the reconstruction of paleoclimate, the search for ancient life and the study of subglacial geological formations. However, it's extremely difficult to core drill subglacial bedrock in Antarctica. Up to now, there're few successful cases of core drilling for subglacial bedrock in the polar region and there's a lack of sufficient samples from the subglacial environment. Compared with the common method of armored cable electro-mechanical auger drilling tools for polar drilling, hydraulic reverse circulation has many advantages, such as no need to lift the drill for coring; small disturbance to the borehole ; not easy to jam the drill; good quality of coring and so on. In order to ensure the successful realization of hydraulic reverse circulation continuous coring, automatic isometric core breaking is a key issue. The purpose of this paper is to carry out an in-depth study of the core breaking mechanism. Establish a mechanical model of core breaking process through the corresponding mechanical theory, analyze the force characteristics and stress state of the core, and explore the fracture criterion applicable to the analysis of core breaking. Measurements of the breaking force and breaking displacement required for the breaking process were made by full-scale experiments in the same low-temperature experimental environment and breaking rate, and under different experimental conditions of core length, core diameter and splitter angle.The required breaking force and displacement are measured and then the theoretical calculation results are fitted to the experimental results, which are combined with the characterization of the cross-section structure and composition of some of the experimental core, to finally obtain the effect of different breaking conditions on the results and to reveal the breaking mechanism of the core.

841

Show Your Work — The Inherent Adventurous Spirit, Hardships and Emotional Bonds of Antarctic Research as Drivers of Public Engagement

Benjamin Burke¹, Dr Petra Heil^2,3

¹Applied Poetics, Oakland, USA. ²Australian Antarctic Division, Kingston, Australia. ³Australian Antarctic Program Partnership, Hobart, Australia

Abstract

Complexity, apathy and desensitization are common obstacles for garnering public attention with charts, graphs and data. How to make the average person appreciate and engage with urgent scientific findings? What makes people sit up and pay attention? What universally nets understanding and appreciation across cultures and across time? Hard work, camaraderie and adventure.

Antarctic researchers are a particularly adventurous breed. It takes a certain kind of character to simply travel to the continent, let alone to spend months surviving on it while conducting complex, in depth science.

This presentation will explore the many facets of Antarctic research to reveal a novel yet simple approach to engaging the public with the vital research and results conducted and obtained on our planet’s southernmost continent in an effort to bolster the call for climate change mitigation across the globe.

Footage of the intricate preparation for and conducting of Antarctic research will be shared to suggest how the inherent adventurous spirit of the researchers themselves, their numerous necessary skill sets, the hardships they overcome, the camaraderie they experience, and the joy of discovery and achievement against all odds out on the ice and in the lab can be leveraged as drivers of interest for both the public and policy makers alike.

This presentation will end with an invitation for attendees to join us and submit their own footage to our team for the creation of an awareness campaign which showcases the inherent beauty and reality of the Antarctic researchers’ human experience normally hidden from public view — the vast breadth and depth of work and emotionality of generations of adventurous characters from multiple countries bonded by purpose, concern and curiosity — in order to engage the public in the urgent fight to mitigate climate change for a livable Earth system.

844

Status and Trends in the Stability of the Three Largest Ice Shelves in Antarctica

Dr Lu AN¹, Dr Rongxing Li¹, Guojun Li¹, Menglian Xia¹, Dr Da Lv², Dr Yuan Cheng³, Aiguo Zhao¹, Tian Chang¹, Dr Xiangbin Cui⁴, Dr Shengkai Zhang⁵, Dr Shijie Liu¹, Dr Yixiang Tian¹, Dr Weian Wang¹

¹Tongji University, Shanghai, China. ²Shanghai Surveying and Mapping Institute, Shanghai, China. ³Shanghai University, Shanghai, China. ⁴Polar Research Institute of China, Shanghai, China. ⁵Wuhan University, Wuhan, China

Abstract

The Ross, Filchner-Ronne, and Amery ice shelves are the three largest ice shelves in Antarctica, playing a crucial role in supporting the Antarctic ice sheet. However, current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors, lacking a comprehensive assessment of multiple parameters. To systematically and in-depth study the stability and trend of the three largest ice shelves, we comprehensively collected and analyzed key parameters, including elevation changes, basal melting, surface meltwater, fracture, suture zones, ice front lines, grounding lines, ice velocity, and mass balance. Additionally, we selected the collapsed Larsen B Ice Shelf (LBIS), the rapidly changing and structurally weakened Pine Island Ice Shelf (PIIS), and the accelerating Totten Ice Shelf (TIS) as reference ice shelves. By comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves, we find the status and trends in the stability of the latter. Our findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to the reference ice shelves. Specifically, 50% of the parameters are smaller than those of the accelerating TIS, 88% are smaller than those of the rapidly changing PIIS, and all parameters are smaller than those of the collapsed LBIS. Furthermore, after analyzing parameters that are not smaller than those of the TIS, it is observed that they remain in a stable state. Hence, the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short term. Nevertheless, the evolution of the ice shelves under global climate change remains uncertain, making long-term observation and monitoring essential to assess their impact on sea level rise.

847

Impact of Storms on the Temporal Evolution of Landfast Ice in Prydz Bay, East Antarctica

Mr. Ajay B, Dr. Jenson V. George, Mr. Pauly Baby John

National Centre for Polar and Ocean Research, Vasco-da-Gama, India

Abstract

The landfast ice cover represents the tiniest fraction of the total sea ice coverage. Despite its size, it holds significant potential for regulating regional and global climates by influencing the exchange of energy, moisture, and gases between the ocean and the atmosphere around Antarctica. Understanding the dynamics of landfast ice is crucial for establishing the complex relationships between climate and ecosystems.

This study delves into the thermodynamic evolution of landfast ice during the winter-to-summer transition period, utilizing a Snow Ice Mass Balance Array (SIMBA) and single-column sea ice models (CICE+ICEPACK). The focus is on understanding the thermodynamic evolution of the ice near Prydz Bay, East Antarctica, while examining the impact of winter storms on the landfast ice system.

Short-lived and episodic synoptic-scale events are observed to transport heat and moisture into the Prydz Bay region. These events rapidly change the surface temperature within 30 hours; the atmospheric temperature changes from -32 to -13.8 degrees. Sudden temperature change induces heat pulses, altering the conductive heat flux is observed. These changes in conductive heat flux raise the internal ice temperature slightly. The signature of heat movement is also visible in SIMBA data, and the model also captures it well during the study period. Moreover, cumulative snowfall from each successive storm deepens the snowpack. It insulates the sea ice, further impeding its growth throughout winter.

Later, these events can delay the occurrence of maximum sea ice thickness and precondition the sea ice, making it more vulnerable to breaking easily during periods of slight wind, particularly during the melt season.

858

Linking the Antarctic sea ice extent changes during 1979–2020 to seasonal modes of Antarctic sea ice variability

Dr. Lejiang Yu¹, Shiyuan Zhong², Prof. Timo Vihma³

¹Polar Research Intitute of China, Shanghai, China. ²Department of Geography, Environment and Spatial Sciences, Michigan State University, East lansing, USA. ³Finnish Meteorological Institute, Helsinki, Finland

Abstract

The Antarctic sea ice extent slowly expanded through the four-decade-long satellite era until 2014 when the expansion came to a halt, followed by a rapid contraction in the next couple of years. This sudden unexpected trend reversal has sparked considerable research interest and several mechanisms have been proposed to explain it; however, much remains to be explored. In this study, we show that the long-term increasing trend in the Antarctic sea ice extent and its recent reversal can be largely explained by the first, second and fourth empirical orthogonal function mode of sea ice variability in austral summer, autumn and spring, respectively. We illustrate that the sea ice variability represented by the three modes is mostly consistent with what is expected from the anomalous atmospheric circulations associated with planetary wavetrains that are triggered by anomalous sea surface temperature (SST) and convective activities over the Southern Indian and Pacific Oceans. More specifically, the results suggest a teleconnection between the increasing periods in the Antarctic sea ice extent in the past four decades and the positive SST anomalies over the southeastern Indian Ocean and the western tropical Pacific Ocean. The opposite occurs over the decreasing period. Accordingly, the same mechanisms, in different phases, have been associated with the periods of increasing and decreasing Antarctic sea ice extent.

861

A proposal for the establishment of a Weddell Sea Marine Protected Area – Phase 2

Dr Cecilie von Quillfeldt, Dr Gary P. Griffith

Norwegian Polar Institute, Tromsø, Norway

Abstract

Norway submitted for consideration by the Commission at CCAMLR-42 in October 2023 a draft conservation measure for the designation of a Weddell Sea Marine Protected Area Phase 2 (WSMPA Phase 2). At CCAMLR-42, the United Kingdom joined as a co-proponent. Since then, the draft conservation measure has been subject to continued improvement thanks to feedback provided by Members during CCAMLR-42 and since.

The proposed WSMPA Phase 2 comprises 849,212 km² within CCAMLR Statistical Subarea 48.6 east of the zero meridian. Two management zones are proposed, i.e. General Protection Zone (GPZ) and Special Research Zone (SRZ). The establishment of the Special Research Zones will along with the General Protection Zones constitute a foundation for the assessment and comparison of various ecosystem drivers, be it fisheries, climate and natural variability across the WSMPA Phase 2 region. This will contribute to an enhanced understanding of circumpolar connectivity regarding transport and migration of key ecosystem components, and the overall role of the WSMPA Phase 2 as part of a representative system of Marine Protected Areas within the CCAMLR Convention Area.

The General Protection Zone (GPZ) consists of five contiguous areas (A, B, C, D, F) and one non-contiguous Area E. In addition to contributing to nine identified MPA protection and scientific objectives, each area has some key conservation values. The Special Research Zone (SRZ) consists of two areas (A.I and C.II) with the same delimitation as the existing (2023) CCAMLR Research Blocks 48.6_3 and 48.6_4 (CM 41-04). With a few exceptions, fishing activities within the WSMPA Phase 2 are prohibited.

The scientific evidence to support the proposal is summarized in an online Atlas (https://tryggve.npolar.no/web/maudatlas/Atlas.html). An interactive decision support tool has been developed to support the analysis of the scientific evidence for the proposed MPA (https://mathmarecol.shinyapps.io/WSMPA2_Discussions/).

862

Scientific rationale for the RINGS efforts facilitating airborne geophysical surveys and relevant resarch of the Antarctic Ice Sheet margin

Dr. Kenichi Matsuoka¹, Dr. Fausto Ferraccioli², Prof. René Forsberg³, Dr. Tom Jordan⁴, Dr. Geir Moholdt¹, Dr. Felicity McCormack⁵, Dr. Kirsty Tinto⁶, Prof. Xiangbin Cui⁷

¹Norwegian Polar Institute, Tromsø, Norway. ²Institute of Oceanography and Applied Geophysics, Trieste, Italy. ³Technical University of Denmark, Lyngby, Denmark. ⁴British Antarctic Survey, Cambridge, United Kingdom. ⁵Monash University, Clayton, Australia. ⁶University of Columbia Lamont doherty observatory, Palisades, USA. ⁷Polar Research Institute of China, Shanghai, China

Abstract

RINGS is an emerging and urgently needed international collaborative effort aimed at conducting airborne geophysics and other field surveys of the Antarctic Ice Sheet margin. This initiative utilizes field data, satellite data, and models to better estimate the Antarctic contribution to global sea-level rise, both presently and in the future. According to the latest IPCC report, the Antarctic Ice Sheet accounts for nearly 50% of the ensemble uncertainty in projections of net sea-level rise by 2100, irrespective of emission scenarios. This uncertainty largely stems from our inadequate understanding of the interconnected, complex system—particularly concerning tipping points—of the Antarctic ice margin, where the ice sheet meets the ocean. The first international RINGS workshop in June 2022 identified scientific priorities along three rings: the primary ring at the current grounding line, the seaward ring across ice shelves and ice rises, and the landward ring located within a few tens of kilometres inland from the current grounding line where the future grounding line would be situated. To further develop the scientific rationale for the high-priority science topics, RINGS has analyzed a range of published data, including the Bedmap3 FAIR database, IBCSO version 2, modelled surface mass balance reconciliation, and results from ISMIP6. Here, we present an overview of these new findings to clarify the scientific rationale for conducting further bed topography surveys in the ice sheet margin.

866

Interannual variability of water masses in Bransfield Strait according to AARI observations in 2016 – 2022

Alexander Klepikov, Nikolay Antipov, Mikhail Molchanov, Sergey Kashin

State Scientific Center of the Russian Federation the Arctic and Antarctic Research Institute, Saint-Petersburg, Russian Federation

Abstract

The main observations of the AARI vessel are carried out on a stationary section through the central basin of the Bransfield Strait, from Maxwell Bay to the continental slope of the Antarctic Peninsula; a series of observations consists of six realizations of the section with a discreteness of a year. Observations along the section through the eastern basin of the strait were carried out twice, in 2018 and 2022.

The temperature and salinity of the bottom layer of Bransfield Strait deep water (BDW), filling the abyssal of the central basin, varied from -1.58 to -1.80 °C and from 34.56 to 34.60 psu, respectively. The trend of warming by more than 0.2 °C (up to -1.578 °C) and desalination by 0.03 psu (up to 34.555 psu), observed in the period 2018-2020, was disrupted by a new cooling of 0.2 °C (up to -1.747 °C) and increase in salinity to 34.59 psu per year.

The variability of the characteristics of the Bransfield Strait flow(BF), manifested in fluctuations in the horizontal (from 10 to 20 km) and vertical (from 200 to 550 m) flow dimensions, has been established. A sporadically appearing tongue of deep water from the Antarctic Circumpolar Current below the BF flow was recorded only in data obtained in 2020–2022. During this period, core characteristics showed noticeable variability in core depth (range 320 – 450 m), temperature (0.4 to 0.9 °C), and salinity (34.58 – 34.63 psu).

A section through the eastern basin of the strait made it possible to detect an increase in the average temperature of the 2200 m thick BDW layer by 0.25 °C over 4 years (with a concomitant increase in salinity by 0.02 psu), reflecting the variability of the climatic scale.

867

Analysis of neutron monitor count rates and timing distributions from latitude surveys

Asst. Prof. Dr. Waraporn Nuntiyakul¹, Dr. Achara Seripienlert²

¹Chiang Mai University, Chiang Mai, Thailand. ²National Astronomical Research Institute of Thailand (NARIT), Chiang Mai, Thailand

Abstract

Neutron monitors continuously record the hadronic part of secondary atmospheric radiation on the ground, which originates from primary cosmic rays. In Thailand, we developed a mobile neutron monitor housed inside a standard-size shipping container named “Changvan.” It contains three neutron-sensitive proportional counters set up in the typical NM64 layout. However, the central counter doesn't have the lead producer, leading us to refer to it as a “semileaded” neutron monitor. We examined cosmic ray spectral variations on two latitude surveys during 2018-2019 and 2019-2020. This work examines the ratio of count rates between leaded and unleaded setups, which shows notable variation based on geomagnetic cutoff rigidity, suggesting a sensitivity to the cosmic ray spectrum. This measurement could be implemented at stationary stations. The unleaded counter, shielded by the reflector with a higher count from nearby lead, may have advantages over a bare one. Furthermore, we explore alternative techniques to identify spectral changes in Galactic cosmic rays using Changvan data. We analyze using time delay histograms to determine the leader fraction (L) of neutrons that are not preceded by another neutron from the same primary cosmic ray. We also examine other parameters, including the alpha (α) parameter and pulse rate (PR), which can be compared with count rates (CR). Our findings indicate that the ratios of L and α are not significantly affected by geomagnetic cutoff rigidity. In contrast, CR and PR exhibit significant dependency and show opposite trends. This talk will also include updates on Changvan's recent 2023-2024 voyage.

870

The influence of global climate change on the water structure of shelf and continental slope in Prydz Bay (eastern Antarctica)

Alexander Klepikov, Nikolay Antipov, Mikhail Molchanov, Sergey Kashin

State Scientific Center of the Russian Federation the Arctic and Antarctic Research Institute, Saint-Petersburg, Russian Federation

Abstract

Observations carried out in the 68-69 RAE (2023 - 2024) showed the preservation in the Prydz Bay of the Commonwealth Sea in the summer of the processes of formation of Antarctic bottom water, which plays an important role in climate change, and was first discovered by AARI scientists in 2004. Repeated (after 2016) execution of a unique test site made it possible to identify important changes in the structure and characteristics of the waters of this area of the Southern Ocean, possibly having significant consequences for climate-scale processes. A significant increase (in comparison with all previous observations since 2004) was discovered in the volume of warm deep water entering the continental slope area from the Antarctic Circumpolar Current. This manifested itself in a noticeable rise in the upper boundary and warm core of deep water, which resulted in a decrease in the depth of winter convection in surface waters and an increase in their temperature. The increase in the intensity of Deep Water input is a consequence of climate scale variability, such as the speed of the Antarctic Circumpolar Current, and in 2023-2024. manifested itself in abnormally low ice cover not only in the Commonwealth Sea region, but also in the Southern Ocean as a whole.

871

The digital repository of the Antarctic Legacy of South Africa displaying South Africa's contribution in the Antarctic region

Ms Maria Olivier

Stellenbosch University, Stellenbosch, South-Georgia and the South Sandwich Islands

Abstract

Increasingly human and social sciences material and data are being recognised as crucial in the world of research. The Antarctic Legacy of South Africa (ALSA) is preserving material of the human involvement from South Africa by maintaining a digital data repository. Material and data in this repository are valuable accounts of South Africa’s Antarctic and sub-Antarctic natural and cultural histories, and create avenues for Antarctic research, overcoming the continent’s remoteness and the challenges of conducting research there. ALSA has been maintaining a digital repository on DSPACE for more than a decade. This poster will give a layout of the digital repository and include the collections that are housed in the repository. It will show that firsthand experiences are documented and preserved for the polar legacy of a country, but to preserve it for the substantial number of scientific deductions and analysis that can be gained from preserving the information. The contribution of human involvement is much more than just pictures and diaries left behind, their work and life can enhance our perceptions of the environment in the polar regions to preserve the future. A qr code to the archive will be available as well as an information brochure.

The repository started in 2009 and at that stage mostly include images diaries and documents. Since then, the collection has been expanded after assessment of material and data that became available as well as the necessity of including current material that will soon become history. The archive has also been reorganised to meet the need of the users and to make the user experience better for researchers to get insight into the past. It is important to know that an archive needs to be transformed to accommodate users and material as this arises during the life span of the archive.

874

SORTING CENTRE OF THE NATIONAL ANTARCTIC MUSEUM - TRIESTE SECTIONAN ITALIAN REPOSITORY FOR MARINE GEOLOGICAL MATERIALS COLLECTED IN ANTARCTICA

Dr Ioanna Protopsalti^1,2, Prof Ester Colizza^1,2, Dr Gianguido Salvi^1,2

¹National Antarctic Museum – Trieste Section, Trieste, Italy. ²Department of Mathematics, Informatics and Geosciences, Trieste, Italy

Abstract

Italy, having ratified the Antarctic Treaty in 1981, has been actively involved in Antarctic research through the National Antarctic Research Program (Programma Nazionale di Ricerche in Antartide – PNRA) since 1985. This initiative has spurred various Italian scientific groups to conduct extensive studies across disciplines, leading to the formation of the National Antarctic Museum (Museo Nazionale dell’Antartide – MNA). The museum, established by the Universities of Genoa, Siena, and Trieste, serves to conserve and study biological, mineralogical, lithological, glaciological and geological-marine samples collected during Italian scientific expeditions, as well as promote the outcomes of the country's scientific community. Each of the three sections is made up of a permanent exhibition, a study and Sorting Centre, and a documentation Centre.

The Sorting Centre of the Section of Trieste is the main repository for geological-marine material from Italian PNRA Antarctic Expeditions since the early 1990s. It stores over 1,000m of deep-sea core sediment, 1,400kg of dredge and grab samples, and 50m of box-cores from Antarctic and Magellan marine areas, including samples from lakes and beaches. The samples are meticulously stored in cold rooms at 4°C for archive material, freezers, and room temperature shelves for sub-samples used in sediment studies. This facility is crucial for preserving and managing these specimens, supporting ongoing and future research in the Italian Antarctic program.

The GIS database contains metadata, including PNRA expedition details, core labels, geographic coordinates, and water depth. It also provides links to digitalized X-rays and preliminary descriptions, creating a comprehensive resource for scientists globally. The emphasis on promoting collaboration has led to the availability of samples for distribution worldwide upon request, fostering knowledge exchange and joint research efforts.

Italy's dedication to Antarctic research, seen through the MNA and Trieste Sorting Centre, underscores its commitment to advancing science and fostering global collaboration.

877

Austral Winter Diatom Community Structure and Function Over Depth in the Palmer Deep, Antarctic Peninsula

Deneb Karentz¹, Angela Zoumplis², Connie Phong³, Cherry Gao⁴, Matthew Sasaki⁵, Zoltán Füssy^2,6, Hong Zheng⁶, Andrew E. Allen^2,6

¹University of San Francisco, San Francisco, CA, USA. ²J. Craig Venter Institute, San Diego, CA, USA. ³Northwest University in Oakland, Oakland, CA, USA. ⁴Massachusetts Institute of Technology, Cambridge, MA, USA. ⁵University of Vermont, Burlington, Vermont, USA. ⁶Scripps Institution of Oceanography, San Diego, CA, USA

Abstract

Diatoms in polar ecosystems are critical to primary productivity, regional food webs and carbon dynamics. Seasonal environmental fluctuations and changes in oceanographic conditions in the Southern Ocean play important roles in diatom community structuring which, in turn, can affect ecosystem functioning and stability. The Antarctic winter is associated with large scale changes in water column and sea ice dynamics that, along with reduced or no sunlight, influence diatom biomass and diversity in the period preceding the spring phytoplankton bloom and summer stratification of the water column. This study provides new insights into the taxonomic composition of Antarctic Peninsula polar night diatom communities over depth. During the 2016 austral winter, water samples were collected at 0m, 20m, 100m and 750m in the Palmer Deep, an area near Anvers Island situated in the Palmer Archipelago. Amplicon sequencing of the 18S rRNA gene and metatranscriptomics sequencing was used to generate a profile of the active diatom community. In shallow water (<100m), the structure of the diatom community remained relatively stable with Fragilariopsis and Porosira as the dominant taxa. The genomic data suggest a significant taxonomic shift with depth accompanied by a decline in species richness. The active dominant genera at 750m were Chaetoceros and Trieres. These genera are known to be capable of transitioning to resting stages, suggesting that these taxa can sink to the bottom and remain viable. Differential gene expression analysis and weighted gene co-expression network analysis (WGCNA) showed distinct differences in activity between surface (0-200m) and mesopelagic (200-1000m) communities. These data shed light on the functionality and adaptive strategies of Southern Ocean planktonic diatoms that persist at depth over the austral winter season.

Samples were collected by the participants of the 2016 US NSF International Antarctic Biology Training Program.

878

First RINGS surveys in Antarctica 2: Probing into Enderby Land, the biggest data gap in Antarctica

Dr. Xiangbin Cui¹, Mr. Xuyu Cheng¹, Dr. Kai Lu¹, Dr. Kenichi Matsuoka², DML/EL RINGS RINGS project members³

¹Polar Research Institute of China, Shanghai, China. ²Norwegian Polar Institute, Tromso, Norway. ³see, below, Norway

Abstract

Enderby Land remains the single largest data gap of modern radar data collected with GPS locations. We carried out the first RINGS surveys probing into Enderby Land as an international collaboration project of 10 nations in the 2023-24 field season using the Polar Research Institute of China’s Snow Eagle 601 aircraft. Because this region has no modern radar data, we aim to carry out this survey as a reconnnessance and to complete the primary ring. While we plan to complete four flights along the entire coast between Zhongshan Station and Princess Elisabeth Antarctica, weatehr conditions prohibited such missions. Finally, we made two flights between 25E – 45E and one flight from 55E – 75E, leaving the coast betweeen 45E and 55E unsurveyed in this first season. The newly collected data along ~6000 km ice sheet margin has highly variable bed topgography, not known earlier. In particular, outlet glaciers in this region have various degrees of topographic controls on their lateral positions, inferring complex responses of this region for climate forcing.

DML/EL RINGS project members (alphabetical order of nations): Jason Roberts, Lenneke Jong, Robb Clifton (Australian Antarctic Division), Frank Pattyn (Universite Libre de Bruxelles), Alain Hubert (International Polar Foundation, Belgium), Sun Bo, Li Lin (Polar Research Institute of China), Olaf Eisen, Daniel Steinhage, Graeme Eagles (Alfred Wegener Institute, Germany), Yogesh Ray, Vikram Goel (National Center for Polar and Ocean Research, India), Masahiro Minowa, Shin Sugiyama (Hokkaido University), Takeshi Tamura (National Institute of Polar Research, Japan), Kenichi Matsuoka, Geir Moholdt, Sven Lidstrom, John Guldahl (Norwegian Polar Institute), Chuma Phamoli (South African National Antarctic Programs), Arjen Stroeven (Stockholm University, Sweden), Jamin Greenbaum (Scripps Institution of Oceanography, University of California), Duncan Young, Don Blankenship (University of Texas Institute of Geophysics, USA)

882

Nature of particulate organic matter in the Bransfield Strait, Antarctica, as revealed by isotopes and molecular markers

PhD Ana Cecília Rizzatti de Albergaria-Barbosa¹, Rayane Vitória Damasceno Menezes², PhD Milena Ceccopieri³, PhD Letícia Lazzari⁴, PhD Moacyr Araujo⁵, PhD Renato da Silva Carreira⁴

¹Federal University of Bahia, Salvador, Brazil. ²Federal University of Bahia, Savador, Brazil. ³Florida International University, Miami, USA. ⁴Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil. ⁵Federal Univeristy of Pernambuco, Recife, Brazil

Abstract

The study of organic matter (OM) dynamics in the Antarctic system is crucial for understanding environmental and biological processes in this region. It is also an essential part of the global carbon cycle and aids in elucidating climate change. The present study aimed to investigate the sources of OM present in suspended particulate matter in the Bransfield Strait (BS, Antarctica) using stable isotopic composition (δ¹³C and δ¹⁵N) and lipid biomarkers (n-alcohols and sterols). Seawater samples were collected from 12 areas at the surface and maximum chlorophyll depth in the BS facing Admiralty Bay on two distinct days in 2019. Water samples were filtered using a calcinated glass fiber filter. Isotopes were determined using an isotope-ratio mass spectrometer. Lipids were analyzed using gas chromatography coupled with mass spectrometry. The δ¹³C and δ¹⁵N values ranged from -31.6 ± 0.3 to -25.7 ± 0.8‰, and from 1.27 ± 0.37 to 3.70 ± 0.75‰, respectively. These values are typical of phytoplankton-derived POM and suggest the influence of mosses. Concentrations of total sterols and total n-alcohols ranged from 148 to 299 µg L^-1 and 79.5 to 171 µg L^-1, respectively. The n-alcohols were dominated by short-chain compounds (14:OH, 16:OH, and 18:OH), confirming the autochthonous source of the OM in the system. Sitosterol was the predominant sterol. This compound has already been reported in bryophytes, suggesting an allochthonous contribution to OM in the BS. The values of the stanols:stenols ratio were low, reflecting the “freshness” of the autochthonous OM in the suspended particles. The analysis of additional samples collected in other years will provide further details on the production and distribution of phytoplankton and moss-derived organic matter observed in these preliminary results.

883

Hierarchical Modelling of Species Communities (HMSC) of benthic species, Potter Cove, King George Island, Antarctica

Dipl. Geogr. Hendrik Pehlke¹, Dr Camila Neder^2,3, María Piotto^4,5, Dr Kerstin Jerosch¹

¹Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ²Universidad Nacional de Córdoba, Córdoba, Argentina. ³Instituto de Diversidad y Ecología Animal, Consejo Nacional de Ciencia y Tecnología, Córdoba, Argentina. ⁴Universidad Nacional de Córdoba, Instituto de Diversidad y Ecología Animal, Consejo Nacional de Ciencia y Tecnología (CONICET), Córdoba, Argentina. ⁵Instituto de Diversidad y Ecología Animal (IDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina

Abstract

Understanding the distribution and coexistence patterns of (benthic) species in Antarctic ecosystems is crucial for the estimation of present and future carbon turnover, ecosystem management, and conservation. Spatial and predictive modeling of environmental and biological data becomes more and more important at remote places to understand and to observe the ecological response to global climate change. In our study, we use the Hierarchical Modelling of Species Communities (HMSC) to model the distribution and coexistence of benthic species based on ecological data. The approach implements a Bayesian framework with Gibbs 'Markov chain Monte Carlo' sampling, and enables to assess the influence of phylogenetic information on species distribution patterns. The HMSC at Potter Cove, West Antarctic Peninsula (WAP), includes a variety of environmental variables, such as water temperature, salinity, bathymetry, distance to the glacier, sediment grain size, suspended particulate matter, and current velocity, among others. As a result, we present habitats for selected benthic communities in prediction maps, and we provide the species composition and spatial variability within the study area. We identify the environmental variables with the highest impact on the benthic community distribution, pinpointing the critical ecological factors in times of climate change. And we learn about the species coexistence patterns, the role of species interactions, and phylogenetic relationships in shaping community structures. The application of HMSC at Potter Cove contributes to the estimation of coastal blue carbon at the WAP, and thus to better coastal conservation planning for Polar regions.

890

Granitoids of East Antarctica and its Rodinian and Gondwanian Counterparts: Contributions to Paleogeodynamic Reconstructions of Rodinia and Gondwana Supercontinent Assemblages.

Nikita Borovkov¹, Dr. Pritom Borah², Dr. German Leitchenkov¹, Igor Kamenev³

¹All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean" (FSBI "VNIIOKEANGEOLOGIA"), Saint-Petersburg, Russian Federation. ²Department of Geological Sciences, Gauhati University., Guwahati, India. ³Polar Marine Geosurvey Expedition, Saint-Petersburg, Russian Federation

Abstract

The East Antarctic shield is characterized by Archean blocks embedded within orogens of Mesoproterozoic, Late Mesoproterozoic-Early Neoproterosoic and Late Neoproterosoic-Early Paleozoic age, and syn- and post-orogenic intrusions composed of different granitoids and related rocks widely spread and making up a prominent volume of the East Antarctic orogens. According to common paleogeodynamic reconstructions of Rodinia, Pannotia and Gondwana supercontinents the East Antarctic shield is a significant volume of supercontinents’ crust. In such respect, petrogenetic models for east Antarctic granitoids became sufficient for any paleogeodynamic reconstractions of supercontinents. We collected structural geology, tectonics, and geochronology data for granitoids intrusions belonging to orogens of Grenvillian and Pan-African age both within East Antarctic shield and African, South American, Indian and Australian counterparts of Rodinia and Gondwana. Collected geochemical data is planned to be plotted in traditional major and rare element tectonic discrimination diagrams and combined with Rb-Sr and Sm-Nd isotope system data. At present moment we created geochemistry database for granitoids of East Antarctic shield. Previous analysis of East Antarctic samples indicated that granitods related to Mesoproterozoic and Late Mesoproterozoic-Early Neoproterosoic orogens formed at different stages of long-lived collision transforming from ocean-continent to continent-continent whereas Late Neoproterosoic-Early Paleozoic opx granitoids are of post-collision tectonic settings. Rare element geochemistry and Sm-Nd isotope system analysis indicate the East Antarctic granitoids originated from the mafic lower-crust source (subducting slab) or their magma is a result of mixing of magmas representing partial melts from the lower-crust and underlying mantle.

891

Forward Treatment for Cold Weather Injury - Mitigating Treatment Delays in Remote and Austere Environments

Dr Jonathon Lowe^1,2, Dr Matthew Warner¹

¹British Antarctic Survey Medical Unit, Plymouth, United Kingdom. ²Academic Department of Military Emergency Medicine, Birmingham, United Kingdom

Abstract

When considering the spectrum of Cold Weather Injury (CWI), any individual who lives, works or operates in an environment below a threshold temperature is at risk of developing an injury. These environments, by their nature of being below a threshold temperature are remote, isolated and often with limited medical capabilities when compared to civilian infrastructure.

Field diagnosis and management of these conditions is also challenging, particularly given the need to rewarm and potentially thaw tissues, requiring suitable conditions to permit injury evaluation. Although this is possible in station medical centres, initiating treatment beyond that of conservative care can be delayed until evacuation to a higher level of care.

Once evacuated, patients are able to receive additional therapies with a focus on preventing further tissue destruction, promoting healing and maintaining function in the affected limb. These therapies require greater infrastructure and are often reserved for use in higher centres of care due to the risk of side effects and complications.

Of these agents, iloprost, a prostacyclin analogue utilised for tissue preservation through systemic vasodilation of capillary beds and effects on platelet aggregation, can be given intravenously with a lesser need for clinical imaging and in the presence of minor trauma. Its utilisation in the treatment of frostbite thus far has been positive with multiple studies noting its effect in reducing amputation.

It is therefore theorised that given its limited need for extensive infrastructure, iloprost can be pushed forward onto continent as an immediate, near-to point of wounding or at diagnosis treatment with limited uplift in medical capability. Further work is required with respect to its risk profile however from the existing literature, it is the authors opinion that iloprost could be considered a suitable first line agent for the management of freezing cold injury on the Antarctic continent.

892

GeoEAIS- proposal for a multinational field campaign program in east Antarctica

Dr. Yogesh Ray, Prof. Naresh Chandra Pant, Dr. Devsamriddhi Arora, Dr. Mahesh Badnal, Dr. Shailendra Saini, Dr. Rahul Mohan

National Centre for Polar and Ocean Research, Goa, India

Abstract

Geological Exploration of Amery Ice Shelf (GeoEAIS), a major project to decipher India-Antarctica linkages, is being addressed through a field campaign being developed by National Centre for Ocean and Polar Research (NCPOR) from the austral summer 2019-20. The central objective is to develop a sub-ice geological map aiming to distinguish the terrain boundaries of Indian, Antarctic and Australian terrains of Proterozoic and older ages and relate the inferred geology to the heterogenous ice mass movements, including those of the Lambert glacier. In the first stage, geological mapping from more than10 locations spread over a ~200 km wide coastal domain has been initiated. The existing geophysical data is proposed to be augmented with additional high-resolution surveys within a ~400km radius of the Indian Research Station Bharati. It is expected to provide a consistent geological interpretation in this sector of PEL and Amery Ice Shelf including characterization of lithospheric and crustal heterogeneities and improved controls for intercontinental correlation especially from Rodinian period onwards. Besides, it is expected to provide critical information for EAIS-bed rock interaction including controls of heat flux. The field campaign will involve facilities for ~10 semi permanent camps as far south as the Grove Mountains and creation of field laboratories.

895

Climate Change Enhanced Wind Drives Physiological Responses in Antarctic Plants

Mr Yifan Wu^1,2, Ms Hao Yin^1,2, Dr Krystal Randall^1,2, Dr Melinda Waterman^1,2, Dr Johanna Turnbull^1,2, Ms Jodie Dunn^1,2, Prof Sharon Robinson^1,2

Abstract

Antarctica is the windiest continent, and coastal East Antarctica has experienced fluctuations in wind speeds that potentially influence the local vegetation. This study explored the driving factors behind shifts in Antarctic wind patterns as well as their impact on terrestrial biodiversity in Antarctica. With a focus on the Windmill Islands region of East Antarctica, we found changes in wind patterns during the summer growing season were most strongly linked to ozone depletion. Furthermore, in order to study the effects of changing wind speeds on the physiological responses of the moss community, we studied physiological responses of three Antarctic moss species— Schistidium antarctici, Ceratodon purpureus, and Bryum pseudotriquetrum collected from two contrasting growth seasons. The 1999-2000 season was colder and windier, less humid and had a higher UV index than the 2002-2003 season. Our analysis focused on the moss water content as a marker for active metabolism and photoprotective pigments as indicators of stress. We used redundancy analysis (RDA) to show that, relative to other climate parameters such as relative humidity, precipitation and air temperature, wind speeds played a dominant role in moss moisture content variation. Higher wind speeds were found to correspond to increased accumulation of photoprotective pigments, especially zeaxanthin. Notably, two cosmopolitan species, C. purpureus and B.pseudotriquetrum,exhibited more rapid and robust pigment responses compared to the endemic species, S. antarctici. These findings suggest that if ozone depletion continues East Antarctica's coastal regions are likely to experience heightened drying during the summer growing season due to increased wind speeds. Moss communities in the region are expected to face intensified survival pressure due to this change in their environment.

896

GRETA (CoolinG oveR thE VicToria LAnd (GRETA): resolving the Ross Sea response to continental climate change during the last two millenia

Fiorenza Torricella¹, Battaglia Francesca¹, Simon Belt², Lucilla Capotondi³, Ester Colizza⁴, Florence Colleoni⁵, Alessio Di Roberto⁶, Leonardo Langone¹, Patrizia Giordano¹, Gesine Mollenhauer⁷, Enrico Pochini⁸, Tommaso Tesi¹

¹Istituto di Scienze Polari, CNR, Bologna, Italy. ²Biogeochemistry Research Centre, School of Geography, Earth and Environmental Sciences, University of Plymouth, Devon, United Kingdom. ³Istituto di Scienze del Mare, CNR, Bologna, Italy. ⁴Dipartimento di Matematica, Informatica e Geoscienze, Università degli studi di Trieste, Trieste, Italy. ⁵Istituto Nazionale di Oceanografia e Geofisica Applicata, Trieste, Italy. ⁶Istituto Nazionale di Geofisica e Vulcanologia, Pisa, Italy. ⁷Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. ⁸Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada

Abstract

Ice core have largely improved our knowledge of short-term climate variability over the last 2ky in Antartica suggesting an abrupt cooling event along the Victoria Land (western Ross Sea, Antarctica). Still no information is available from the marine sedimentary record. GRETA proposes to fill this knowledge gap by investigating the ocean response to a cooling event recorded over the Victoria Land (ca 1.3-1.9 ky CE). We present new high-resolution sedimentary sequences collected in different sectors of the western Ross Sea (Granite Harbour and JOIDES Basin), comparing the new data with existing data collected in Wood Bay and Edisto Inlet (Tesi et., 2020; Mezgec et al., 2017). We use a multidisciplinary approach that includes micropaleontological analyses (diatom assemblages), geochemical analyses (biomarkers such as IPSO₂₅ and PIPSO₂₅, organic carbon and stable isotope analyses, TEX86-L/RI-OH’) and sedimentological analyses (grain size analyses and sortable silt determination). The final goal of our project is to reconstruct the sea ice dynamics and water mass properties (sea surface temperature, water mass circulation, upwelling) during the last 2,000 years in the western Ross Sea. We propose the first reconstruction of SST for the western Ross Sea covering the last 2,000 years and its relationship with the corresponding continental climate events. Finally, we will merge the information obtained from the marine domain with ice core and model data to provide new insights into the sub-millennial variability of atmosphere-ocean interactions.

897

The SOCCO Trajectory - A brief synopsis of our origin, emergence and scientific insights that link fine scale dynamics to large scale carbon-climate feedbacks

Dr Sandy Thomalla^1,2, Prof Pedro Monteiro³, Dr Nicolette Chang¹, Dr Sarah Nicholson¹, Dr Thomas Ryan-Keogh¹, Dr Precious Mongwe¹, Dr Siyabulela Hamnca¹, Dr Thulwaneng Mashifane¹

¹Southern Ocean Carbon–Climate Observatory, CSIR, Cape Town, South Africa, Cape Town, South Africa. ²Marine and Antarctic Research for Innovation and Sustainability, University of Cape Town, Cape Town, South Africa. ³School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa

Abstract

This presentation shares the journey of the South African Southern Ocean Carbon-Climate Observatory (SOCCO) from humble beginnings to a leading research capability that addresses the role of the Southern Ocean in 21st century regional and global climate. As a small research group, a niche approach was needed to address this grand challenge. This led to the formulation of an underpinning hypothesis that fine-scale ocean dynamics are key to understanding climate sensitivity through their impacts on the variability and trends of carbon fluxes in the Southern Ocean. An emergent need to understand and constrain the seasonal cycle led to the development of observational and modelling capabilities that could resolve the relevant scales and involved pioneering Southern Ocean robotics experiments, remote sensing and high-resolution modelling. It has been a journey fraught with difficulties and the occasional disappointment but ultimately eclipsed by moments of realisation of achieving innovative and pertinent science. This presentation will showcase some key insights that make a growing contribution to our understanding of the role that fine-scale dynamics play in shaping the seasonal cycle and its inter-annual variability. Results highlight the need for climate models to resolve meso- to submesoscale and intra-seasonal processes in order to accurately reflect and understand the sensitivity of the Southern Ocean to climate change.

901

Response of the coccolithophore Calcidiscus leptoporus to environmental change during the industrial era in the sub-Antarctic Southern Ocean

Dr. Andres S. Rigual-Hernández¹, Dr G. Langer², Dr. F.J. Sierro¹, Dr. M. Angeles Barcena¹, Dr H. Bostock³, Dr. J.M. Sánchez-Santos¹, Dr. S.D. Nodder⁴, Dr. A.D. Moy⁵, Dr A.M. Ballegeer¹, Dr. R. Eriksen⁶, Dr. J.A. Flores¹

¹University of Salamanca, Salamanca, Spain. ²ICTA, Autonomous University of Barcelona, Barcelona, Spain. ³School of Earth and Environmental Sciences, University of Queensland, Brisbane, Queensland, Australia. ⁴National Institute of Water and Atmospheric Research, Wellington, New Zealand. ⁵Institute of Marine and Antarctic Studies, Hobart, Tasmania, Australia. ⁶Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia

Abstract

The Southern Ocean is an essential component of the global thermohaline circulation and an important sink for anthropogenic CO₂. However, the physical and chemical properties of its surface waters are undergoing rapid and relentless change. The rate of warming of Southern Ocean waters exceeds that of the global ocean, while increased CO₂ uptake is causing a reduction in pH and a decrease in the concentration of carbonate ions, a process known as ocean acidification. This pronounced change in ocean water properties poses a serious risk to marine ecosystems in general and to marine calcifying organisms in particular.

Coccolithophores are the most prolific group of marine calcifying phytoplankton and are important contributors to pelagic production of particulate organic and inorganic carbon. Satellite reflectance observations suggest the development of extensive coccolithophore blooms in the sub-Antarctic circumpolar zone during the austral summer. Therefore, changes in coccolithophore composition and calcification may have important consequences for Southern Ocean marine ecosystems and ocean chemistry, ultimately affecting climate.

Here we compare the morphometric parameters of coccoliths of the keystone species Calcidiscus leptoporus across different time scales. In particular, we compare coccoliths collected during an annual cycle by a sediment trap, with those in the underlying sediments and in a sediment core comprising the Holocene. Our results show that some morphometric parameters of coccoliths are significantly correlated with changes in carbonate chemistry, suggesting that continued increases in CO₂ emissions will have a negative impact on C. leptoporus growth.

903

The critical importance of Wilkes Land Subglacial Basin stability (East Antarctica)

Dr Florence Colleoni¹, Dr Laura De Santis¹, Dr Giulhem Barruol², Dr Pierre Dutrieux³

¹National Institute of Oceanography and Applied Geophysics, Trieste, Italy. ²Institut des Géosciences et de l'Environnement, Grenoble, France. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

While most of West Antarctic ice shelves are thinning due to ongoing oceanic warming, East Antarctic ice shelves, except a few ones, are apparently more stable. One sector in particular, the Wilkes Subglacial Basin, is not showing any sign of weakness to ongoing climate change. This sector of Antarctica is drained by the Cook ice shelf, the Ninnis ice shelf and the Mertz ice tongue. Those ice shelves have experienced some observed calving events in the past decades, but actual ice flow does not indicate that this sector is retreating and contributing to global mean sea level rise. But can we really measure the sensitivity of a sector only accounting for two decades of observations? Geological archives and morphological evidence of the George V Land continental margin in front of those glaciers suggest, on the contrary, that the ice sheet over the WSB has been one of the most active of East Antarctic sectors through its glaciological history. A multi-year sea ice cover, reducing only under exceptional atmospheric conditions, does not allow the systematic exploration of the area. Rare geophysical, glaciological, oceanographical, geological and geographical hampers a proper assessment of the instability potential of this area. International cooperation not only is needed to reach and operate in such difficult sector of Antarctica, both at land and on sea, but is also needed to perform multi-disciplinary measurements.

906

The cryptogamic cover in the Antarctica: the response to temperature discriminates endemic and cosmopolitan species

Ana Pintado¹, Jose Raggio¹, Claudia Colesie², Nuria Beltrán-Sanz¹, T.G.Allan Green^1,3, Ana Aramburu¹, Leopoldo G. Sancho¹

¹Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain. ²School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom. ³Biological Sciences, University of Waikato, Hamilton, New Zealand

Abstract

The cryptogamic tundra in maritime Antarctica is composed of lichens and mosses of diverse phylogeographic origins. Around half of the total cryptogamic flora is made up of species that are either endemic or cosmopolitan, yet these two groups are at opposite poles of the phylogeographic classification. For cosmopolitan species the maritime Antarctic represents a small part of their global distribution whereas, for endemic species, it constitutes their only available location. The two groups have evolved under dissimilar geographic and environmental conditions and might be expected to show different adaptive potential, having been selected to meet distinct limiting factors. For instance, under a warming scenario, it might be expected that cosmopolitan species will have adaptive advantages compared to the endemic ones. To test this hypothesis, we investigated the response of net photosynthesis to light intensity and temperature for some of the most abundant species of lichens (Himantormia lugubris, Usnea antarctica, Sphaerophorus globosus, Stereocaulon alpinum) and mosses (Andreaea gainii, Sanionia uncinata) belonging to different phylogeographic categories. We used standard CO₂-exchange techniques under fully controlled measurement conditions to generate response curves of net photosynthesis to light and temperature. From these, we determined the respective optima obtaining significantly higher values of optimal temperature for the cosmopolitan species. In addition, we recorded the microclimatic conditions when selected species of each phylogeographic category were active in their natural habitats on Livingston Island (South Shetland Islands), using dataloggers and chlorophyll fluorescence monitoring. Both endemic and cosmopolitan species where most of the time active at around 4 ºC but while endemics were active always below 13 ºC, the cosmopolitans showed activity at temperatures up to 25 ºC. In conclusion, although growing well under present environmental conditions, cosmopolitan species (both lichen and mosses) showed a positive response to warmer temperatures that was not detected in the endemics.

908

Challenging the Medical Paradigm - The Development of Novel Medical Care Pathways in the Polar Environment

Dr Jonathon Lowe^1,2, Dr Matthew Warner¹

¹British Antarctic Survey Medical Unit, Plymouth, United Kingdom. ²Academic Department of Military Emergency Medicine, Birmingham, United Kingdom

Abstract

Operating in any remote or austere location is associated with novel challenges for healthcare providers, largely due to the environment but also how care pathways are provided in a place with limited healthcare infrastructure.

One of potential challenges is the issue of attempting to providing 'temperate' medical care paradigms in the polar environment. Temperate practice utilises electro-medical equipment (EME) that is either not rated to or has not been trialled in the same environment in which it is employed. Temperate practice also associates particular timelines to intervention with outcome measures which are again challenging to meet in the polar environment.

Understanding outcomes in care from a remote location is important as a direct parallel can be drawn between operating on the Antarctic continent and in the space domain.

We, the authors, propose that novel care pathways are required for the polar environment in order to optimise care outcomes whilst deployed. An example of this would be in the management of non-hypothermic cardiac arrest - an established advanced life support algorithm exists for in-hospital care however when management necessitate functional EME and short transfer times, can this be mapped accurately to providing care in the deep field?

Further research is required to establish the viability of holding and utilising EME at extreme reach and outside of temperature controlled environments. Additional work looking at the risk profile of interventions should also be considered - particularly around the use of alternative interventions when compared with in-hospital practice.

This proposal is to be considered as an invitation for international collaboration, with an initial phase to review literature outlining the risk profile of interventions and environmental testing EME, before further reviewing care algorithms for the addition or modification for 'polar' specific interventions.

912

Diatom-based Relative Sea Level Changes from Sedimentary Deposits of the Discussion Lake, Larsemann Hills, East Antarctica.

Mr Jadav Avirajsinh, Dr Mahesh BS, Dr Abhilash Nair, Dr Cheryl A. Noronha-D'Mello, Dr Rahul Mohan

National Centre For Polar And Ocean Research, Goa, India

Abstract

Prydz Bay, a significant embayment on the East Antarctic coast, discharges roughly 16% of the East Antarctic Ice Sheet. Geological evidence of past relative sea-level (RSL) changes is found at the Vestfold Hills, Rauer Islands, and Larsemann Hills. Studying past RSL changes in the Larsemann Hills is crucial because of its proximity to the Lambert Glacier, currently the largest glacier of the Antarctic Ice Sheet. It's also a key area for ice sheet accumulation in models reconstructing the Antarctic ice sheet during the Last Glacial Maximum (LGM). Here, we examine a 2 m long radiocarbon dated sediment core (DL3) retrieved from Discussion Lake, a low elevation (5 m a.s.l) coastal lake in the Larsemann Hills of East Antarctica. The core spans up to 7500 yr. Sediment stratigraphy, geochronology, and diatom were used to infer the paleoenvironmental changes of the Holocene. Based on diatom assemblages, we found the dominance of marine species viz., Achnanthes brevipes, Fragilariopsis curta, Fragilariopsis cylindrus, Navicula glaciei, and Actinocyclus curvatulus from 7507 to 3145 cal yr. BP. This indicates the basin was under submarine conditions, and the RSL was higher than 5m during the mid-Holocene. The higher abundance of Amphora veneta (typical of deeper (>4 m) brackish water species), between 3145–1890 cal yr. BP suggests a transition zone. This indicates the fall of the RSL as the isostatic upliftment (caused by ice sheet retracement) outpaces the rise of the eustatic sea level. The lake became an isolated basin from 1890 cal yr. BP to present. Freshwater diatoms dominated the diatom assemblages as the lake became isolated, such as Stauroforma inermis, Psammothidium abundans, Pinnularia microstauron, and Diadesmis perpusilla. This study helps to understand the glacial isostatic adjustments of the region and constrains the RSL curve noted in the area.

917

Gravity waves in the mesosphere lower-thermosphere over Rio Gallegos, Argentina, near Andes, and comparison with the Syowa Station, Antarctic.

Prof. Takuji Nakamura^1,2, Dr. Mitsumu K. Ejiri^1,2, Dr. Masaru Kogure^3,4,5, Dr. Septi Perwitasari⁶, Dr. Yoshihiro Tomikawa^1,2, Prof. Masaki Tsutsumi^1,2, Prof. Akira Mizuno⁷, Dr. Katsuhiko Tsuno⁸, Dr. Takayo Ogawa⁸, Dr. Satoshi Wada⁸, Dr. Jacobo Salvador⁹

¹National Institute of Polar Research, Tachikawa, Tokyo, Japan. ²Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Tokyo, Japan. ³Faculty of Science, Kyushu Univ., Fukuoka, Japan. ⁴NASA Goddard Space Flight Center, Greenbelt, MD, USA. ⁵Physics Department, Catholic University of America, Washington, DC, USA. ⁶National Institute of Information and Communications Technology (NICT), Koganei, Tokyo, Japan. ⁷ISEE, Nagoya University, Nagoya, Aichi, Japan. ⁸RIKEN, RAP, Wako, Saitama, Japan. ⁹National Scientific and Technical Research Council (CONICET), Santa Cruz, Argentina

Abstract

Atmospheric gravity waves play important roles in couplings in the terrestrial whole atmosphere, by transporting momentum and energy vertically and horizontally. There are various sources of gravity waves such as meteorological disturbances, the surface topography, instability of jet stream, etc. The secondary wave generation caused by breaking gravity waves in the middle atmosphere is also one of the sources known recently. The description of gravity waves are still one of the important challenges of the detailed modelling of the whole atmosphere dynamics for various time scale of forecasting. Compared to the northern hemisphere, observational studies of gravity waves are less extensive. One of the hotspots, i.e. active source region of such gravity waves, in the southern hemisphere is the area of the Andes and the Antarctic peninsula. As an extension of ANGWIN (Antarctic Gravity Wave Instrument Network), we installed an all-sky airglow camera in November 2017 at Rio Gallegos station (51.6S, 69.3W), Patagonia, Argentina.

The imager system is equipped with an InGaAs array sensor, sensitive to the near-infrared (900-1700 nm), and can observe OH Meinel band airglow (~87 km altitude), obtaining 2D horizontal image of OH airglow every 5 sec. This system is almost identical specification of the imager at Syowa station (69S, 40E), the East Antarctic, operated since 2016.

This paper presents the results of gravity waves observed in 2018 at Rio Gallegos, Patagonia, over 138 clear-sky and moonless nights. Compared with other observations at different locations, this observation showed very frequent existence of quasi-stationary wave, that suggests mountain wave generation. Also, so many wave breaking events have been recognized, indicating very larger amplitudes of the waves over the Andes. The results will be compared with those from Syowa Station, Antarctic, and the effects of mountain waves over the Andes, the gravity wave hotspot, will be discussed.

919

Retrieving High-Resolution Ice Core Records and Radar Stratigraphy from Canisteo Peninsula, West Antarctica

Dr Peter Neff¹, Dr Yeongcheol Han², Dr Vikram Goel³, Julia Andreasen¹, Chaewon Chang², Songyi Kim², Jangil Moon², Dr Won Sang Lee², Dr Kenichi Matsuoka⁴, Dr Laluraj C. M.³, Dr T J Young⁵

¹University of Minnesota, Minnesota, USA. ²Korea Polar Research Institute, Incheon, Korea, Republic of. ³National Centre for Polar and Ocean Research, Goa, India. ⁴Norwegian Polar Institute, Tromso, Norway. ⁵University of St Andrews, St Andrews, United Kingdom

Abstract

The coastal region of West Antarctica is undergoing rapid changes due to poorly understood ice-ocean-atmosphere interactions. Ice rises, grounded ice bodies within ice shelves, provide ideal sites for reconstructing past coastal climate. In January 2024, as part of the Ross-Amundsen Ice Core Array (RAICA) project, supported by the South Korean icebreaker RV ARAON and two helicopters, an international team of 8 people camped for 13 days at the Canisteo Peninsula ice rise, in West Antarctica. During this period, the team drilled two 150-m-long ice cores 1 km apart on either side of the summit. The recovered ice cores will be used to reconstruct high-resolution paleoclimate records spanning past several centuries. Complementing the ice core data, a comprehensive ground-based radar survey was conducted using shallow-sounding radar mapping the englacial ice stratigraphy of the top ~90 m over the ice rise. This data will be used to understand the spatio-temporal variability in surface mass balance in the region. Additional survey using a deep-sounding radar was conducted in the vicinity of the ice rise summit. Initial results show ~600 m thick ice over a smooth bed, with distinct, double Raymond arches, a stratigraphic feature suggesting a stable summit position for the past several millennia. ApRES repeat measurements were also conducted at one of the ice core site to constrain the vertical strain rates. Together these ice core and radar data will be used to advance our understanding of coastal West Antarctic climate variability, extremes, and trends over recent centuries, providing vital constraints for climate models and reanalysis products, crucial for improving projections in this rapidly evolving region.

921

Harmony in the Polar Realms: Fostering Collaboration and Demilitarization for Future Stability

Dr. Monojit Das

Kolkata, Kolkata, India

Abstract

The polar regions, with their unique atmospheric and geospatial dynamics, offer invaluable insights into global environmental processes. Amid evolving geopolitical landscapes and the rise of power blocs, collaborative efforts in these regions are increasingly crucial. This abstract advocates for fostering cooperative ventures in the polar realms, highlighting the interconnectedness of atmospheric and geospatial phenomena and their impact on global dynamics.

As multipolarity shapes geopolitics, the polar regions gain prominence for their strategic significance and resources. This evolution presents challenges and opportunities, necessitating a shift towards collaboration. Inclusive dialogue and cooperative frameworks are imperative as power blocs vie for influence. Research in the polar regions advances scientific understanding and affects global climate dynamics, requiring concerted efforts across boundaries. Collaborative initiatives can address pressing research questions and shared environmental challenges.

This work outlines a forward-looking framework for the polar regions, stressing collaboration and demilitarization. Anticipating evolving geopolitics and security challenges, it lays the groundwork for proactive measures in the Arctic and Antarctic. By analyzing trends and proposing interventions, this paper informs policy discussions for a future where poles remain zones of cooperation and environmental protection.

The work will examine the intersection of geopolitics, security, and environmental governance, projecting potential pathways for collaboration and conflict resolution. It identifies drivers of change like rivalries and resource competition, exploring their impact on the region's security. Drawing on scenario planning, the paper envisions alternative futures and evaluates implications for stability and global security.

Additionally, it reflects on strengthening existing governance frameworks and proposes innovative approaches to enhance transparency and trust among stakeholders. Emphasizing scientific diplomacy's role in climate research and sustainable development, the paper underscores potential for cooperation. Thereby addressing challenges and seizing collaboration opportunities, stakeholders can shape a future where polar regions foster international cooperation and scientific discovery, contributing to global peace and sustainability.

922

The influence of Indian Ocean Dipole on precipitation over East Antarctica

Dr Emilia Kyung Jin, Dr Hyun-Ju Lee

Korea Polar Research Institute(KOPRI), Incheon, Korea, Republic of

Abstract

East Antarctica is undergoing a noticeable decrease in precipitation, significantly impacting ice mass loss. However, there is a lack of research on the underlying factors behind this change. This study highlights that on an interannual timescale, the precipitation variations in Eastern East Antarctic (EEA) are predominantly influenced by the Indian Ocean Dipole mode (IOD) compared to other climate variabilities like the Southern Annual Mode (SAM), El Niño–Southern Oscillation (ENSO), and north Atlantic variability. Through trend analysis of each climate variability, we confirmed that the observed decrease in EEA precipitation can be attributed to positive IOD-like ocean warming. A positive SAM trend also contributed to specific Wilkes Land and Queen Mary Land regions. Despite these influence on long-term trend, the relationship between IOD and EEA precipitation exhibits sporadic changes on interdecadal timescales. Notably, the apparent negative correlation between the two declined to insignificance in the early 2000s, only to re-establish a significant negative correlation by the early 2010s. The primary driver of this change is the inconsistent propagation of waves originating from the Indian Ocean. During periods of high correlation, these waves propagate southeastward, inducing a robust low-pressure anomaly near Victoria Land, ultimately leading to decreased EEA precipitation. However, during periods of low correlation, the waves move eastward and fail to alter the circulation anomalies near East Antarctica.

923

Urologic emergency in Antarctica: A unique challenge

Dr. SHALINI NANGALIA¹, Dr VIKAS DOGRA², Dr PRADIP MALHOTRA³, Dr ANURAG SHARMA⁴, Dr ANKUSH DESHMUKH⁵, Dr Aakash Kanojia⁶, Mr Manish Kumar⁷, Mr Sudhanshu Khokhar⁶, Dr Rufus Edwin⁸, Dr Priyankar Datta⁹, Dr Vikram Hegde¹⁰

¹NATIONAL CENTRE OF POLAR AND OCEAN RESEARCH, GOA, India. ²RAJIV GHANDHI SUPER SPECIALITY HOSPITAL, DELHI, India. ³MINISTRY OF HEALTH AND FAMILY WELFARE, NEW DELHI, India. ⁴Amrita Institute of Medical Sciences and Research Centre, Faridabad, India. ⁵Jupiter Hospital, Mumbai, India. ⁶NCPOR, Goa, India. ⁷NCPOR, Delhi, India. ⁸NCPOR, GOA, India. ⁹AIIMS, Delhi, India. ¹⁰Kumta Hospital, karnatka, India

Abstract

Introduction -

Bilateral obstructing ureteric calculi leading to anuria is unusual and can potentially result in acute hydronephrosis by obstructing the urinary flow which may lead to rapid deterioration of renal function. So, in the remote environment of Antarctica, such cases should be managed promptly.

Case Presentation-

A 34-year-old gentleman presented with a complaint of inability to urinate for one day. The patient had one episode of burning micturition which was associated with pain in the right flank and was followed by anuria. On ultrasonography, an empty bladder with bilateral hydronephrosis was observed. Plain X-ray KUB was done which suggested bilateral ureteric calculi. It included antibiotic, anti-spasmodic, fluid restriction and oral steroid after consultation with a mainland urologist. Kidney function test and serum electrolytes were planned to be done. In the absence of immediate test results and possibility of acute kidney injury, prophylactic management to prevent hyperkalemia, was instituted which included ECG monitoring. To rule out possibility of fluid overload and pulmonary edema, thoracic ultrasound was done to rule out B lines, if any. While awaiting evacuation of the patient, he was able to urinate and passed a calculi measuring 3mm in maximal diameter. As there remained a possibility of recurrence, so medical evacuation to South Africa was planned where laser lithotripsy and DJ stenting was preformed and the patient was discharged in stable condition.

Conclusion-

This was a challenging case of a patient presenting with anuria due to bilateral ureteric calculus. After examination and using point of care devices at Indian Antarctic Station, it lead to the diagnosis. Use of telemedicine for further management was indispensable. Coordinated efforts for timely medical evacuation to prevent recurrence and subsequent possibility of Acute Kidney Injury led to the safe return of the patient back to India.

Keywords -

Anuria, calculi, acute kidney injury, evacuation

924

Paleoclimatic/paleoenvironmental scenario, through a Holocenic sediment core from Jurasee Lake (JL) at Fildes Peninsula/King George Island/Maritime Antarctica

M.Sc. Flavia Tavares¹, Ph.D Heitor Evangelista¹, Ph.D Sergei Verkulich^2,3, Ph.D Yury Kublitskiy², Ph.D Ligia Pérez-Cruz⁴, Ph.D Rafael Venegas-Ferrer⁴

¹Rio de Janeiro State University, Rio de Janeiro, Brazil. ²Herzen State Pedagogical University of Russia, St. Petersburg, Russian Federation. ³Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation. ⁴National Autonomous University of Mexico, City of Mexico, Mexico

Abstract

This research sets a Holocene paleoclimatic/paleoenvironmental reconstruction through physical and geochemical analysis of a lacustrine sediment core collected in a pro-glacial lake at Antarctic Peninsula. The core, named JL, was retrieved at the centre of Lake Jurasee (62°13'20.91"S, 58°59'59.60"W; core depth 2.8 m; 49 masl), in a flat, wide and short valley located at the southern of the Fildes Peninsula in King George Island. X-ray fluorescence (XRF) data of Al, Si, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Sr, Zr, Rb and Sn was recovered throughout the 2.8 m of the core JL. Based on elemental composition and lithological descriptions, it’s possible to identify two major sediment depositional phases. The first section of the core JL (280-110 cm depth) shows higher SM values, (301-541)*10^-5SI, as well as higher Al, Cl, K, Ca, Ti, Mn, Fe, Sr and Zr contents. Those results demonstrate a period of lower temperatures and high and large inputs of meltwater (or meteoric precipitation) to the lake. The second section, which corresponds to the period around 4900 yr BP (110 cm-top depth), presents the lowest MS values, (28.5-109.3)*10^-5SI, and geochemical rates. This indicates a reduction in leaching processes due to the increase in ice-covered. Some lake core segments stand out to have abrupt variations in the elemental contents and MS values, such as between 190-170 cm (sharp decrease), 140-120 cm (general decreasing trend), 100-80 cm (fast rise) and, 20-0 cm (increase). These changes indicate a marked transition phase in the paleoclimatic conditions of the study area during the Holocene, that was also reported to other lacustrine environmental at that region and for James Ross ice core, but with slightly different timing. These changes are part of the history of climate and landscape evolution in the North of the Antarctic Peninsula.

926

MAASTRICHTIAN-EOCENE ECHINODERMS FROM SEYMOUR ISLAND, ANTARCTIC PENINSULA

Bruna Poatskievick-Pierezan^1,2, Bruna Camila Schneider², Leslie Manríquez³, Rodrigo do Monte Guerra^1,4, Mariuz Salamon⁵, Juliana Lúcia Franken^1,2, Rodrigo Scalise Horodyski², Karlos Guilherme Diemer Kochhann^1,2, Gerson Fauth^1,2, Sandro Marcelo Scheffler⁶

¹Instituto Tecnológico de Paleoceanografia e Mudanças Climáticas, São Leopoldo, Brazil. ²Universidade do Vale do Rio dos Sinos, São Leopoldo, Brazil. ³Intituto Antártico Chileno, Punta Arenas, Chile. ⁴Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil. ⁵Uniwersytet Śląski w Katowicach, Sosnowiec, Poland. ⁶Museu Nacional, Rio de Janeiro, Brazil

Abstract

Seymour Island, located in the northeastern part of the Antarctic Peninsula, is famous for the widespread occurrence of fossils dating from the Late Cretaceous to the late Eocene. The PALEOCLIMA Project, carried out scientific expeditions in 2019–20 and 2022–23 with the aim of collecting rocks and fossils seeking information about climate changes over the last 66 million years. During these collections, four important deposits of echinoderm fossils were described, in the López de Bertodano (Maastrichtian-Paleocene), Sobral (Paleocene) and La Meseta (Eocene) formations. This study presents preliminary data on the taxonomic classification of echinoderms collected during fieldworks. In the López Bertodano formation, dozens of sea urchin spines were collected. Some of them belong to, them are the species Cyathocidaris nordenskjoldi Neraudeau, Crame & Kooser, 2000, C. patera Neraudeau, Crame & Kooser, 2000, and others are new species, at least three families not yet mentioned in this formation (in prep.). In the Sobral Formation, in a stratigraphic section of approximately 15 meters, two intervals were described with the accumulation of columnals of crinoids of the genus Metacrinus Carpenter, 1884. In the La Meseta Formation, towards to base of the section, a single specimen of Stigmatopygus andersoni Lambert, 1910, was found, an echinoderm from the Echinoidea class with excellent preservation that inhabited shallow waters. In the middle part of the stratigraphic section, a level rich in specimens of Zoroaster marambioensis Palópolo, Brezina, Casadio, Griffin & Santillana, 2021, an echinoderm from the class Asteroidea that inhabited shallow waters, was described. In the next activities of this study, analyses using X-ray diffraction, Scanning Electron Microscopy and X-ray microtomography are planned to understand how and under what conditions the preservation of these fossils occurred, and refine the taxonomy of some specimens. [PROANTAR – PALEOCLIMA: 442676/2018-2; FLORANTAR: 442765/2018-5]

929

Moving knowledge of Antarctica and ocean: from Academic Review to Teaching and Society

MSc. Matheus Batista¹, Dr. Thiago Monteiro¹, Dr. Andréa Carvalho², Ms. Bárbara Araújo², Ms. Laura Buss¹, Ms. Cecília Pereira¹, Dr. Mariele Paiva¹, MSc. Letícia Baldoni¹, Dr. Rodrigo Kerr¹

¹Universidade Federal do Rio Grande, Rio Grande, Brazil. ²Universidade Federal do Ceará, Fortaleza, Brazil

Abstract

The dissemination of scientific knowledge plays an important role in preparing and empowering society to cooperate with the challenges faced by the world in the search for sustainable development. With a focus on a social responsibility, we have put efforts into spreading knowledge about the ocean and Antarctica in an accessible language for Brazilian society. We promote this through publications on social media, which are widely used in Brazil, and actions in elementary schools and regional events. These actions make up a broader project, entitled “Moving knowledge of Antarctica and the oceans: from Academic Review to Teaching and Society” (MARES). MARES aims to contribute to ocean literacy by disseminating the concept of a single ocean, with the Southern Ocean appearing as a central region of global importance. Furthermore, our goal is to share academic knowledge about the ocean and Antarctica, in plain language, through our scientific communication magazine CARBON Team News (CTNews). Its content focuses mainly on the issue of climate change related to the carbon cycle and ocean acidification in various marine environments. The magazine has five volumes with easy-to-read sections about the ocean and Antarctica and has had 15 members of the editorial board (10 women and 5 men), with educational backgrounds ranging from undergraduate to postdoctoral levels. To bridge the gap between academia and society we use various approaches (e.g. contests, pools, forms), as well as images, schematic drawings, and comic books, to ensure equal comprehension by society. Thus, we aim to contribute to enhance people's awareness and concern for the ocean and Antarctica, as well as to apply scientific information to their daily lives and socio-political decision-making processes. This has the potential to empower young students to critically access media messages, produce their own content to have a voice in society and shape a sustainable future.

930

Coordinated glacier monitoring: a view to the Chilean Andes

Daniela Carrión, Jorge Huenante, Isabella Ciocca, Hernaldo Leyton, Franco Buglio, Felipe Perez, Diego Gonzalez, Alexis Segovia, Jorge O’Kuinghttons

Dirección General de Aguas, Gobierno de Chile, Santiago, Chile

Abstract

The Glaciological Yearbook consists in a collection of surveys of 25 glaciers on glacier area variation, 8 scheduled reports of mass balances, 3 glaciological monitoring and the report of status of glaciological stations, where the hydrological year (t) is defined from April 1 of the calendar year (t-1) to 31 March of the calendar year (t), and:

The mass balance constitutes a detailed calculation of the gain/loss of a glacier’s ice mass over the course of the hydrological year (t). For the hydrological year 2022-2023 (t), a total of 8 glacier mass balance reports were carried out: 7 discovered and 1 covered. The first seven correspond to the glaciers Tapado (Elqui river basin, Northern Macrozone); Juncal Norte (Maipo river basin, Central Macrozone); Echaurren Norte, San Francisco and Bello (Maipo river basin, Central Macrozone); Nevados de Chillán (Itata river basin, Southern Macrozone); Mocho Volcano (Río Bueno basin, Southern Macrozone). The covered glacier corresponds to the Pirámide (Maipo river basin, Central Macrozone).

Glaciological monitoring during the hydrological year 2022-2023 (t) contemplates the measurement of ablation and/or accumulation using beacons or by terrestrial LiDAR of an ablation sector of the glacier, and/or measurement of the speed of the glacier, and/or installation of a mobile glaciological station. In this case, monitoring reports were made on 2 glaciers in the southern macrozone: Exploradores (Coastal basins and Islands between Río Aisén and Río Baker and Canal General Martínez), Calluqueo (Río Baker basin) and Tyndall (Coastal basins between Seno Andrew and Río Hollemberg and Islands to the East).

The status of the glaciological stations corresponding to the hydrological year 2022-2023 (t) consists of a summary report with the list of all the stations in the monitoring network. Where applicable, it is indicated: measurement variables, geographic location and notable records.

932

Metals along ancient mosses as bioindicators of anthropogenic activities in Antarctica

Ms Hao Yin^1,2, Dr Melinda Waterman^1,2, Dr Andrew Langendam³, Dr Annaleise Klein³, Dr David Paterson³, Mr Yifan Wu^1,2, Prof Sharon Robinson^1,2

Abstract

Antarctica is not the pristine wilderness that is commonly perceived. Since the 1960s, reports have indicated the presence of human pollutants, including heavy metal contamination, in Antarctica. Subsequently, there has been increasing research on various pollutants in abiotic and biological samples from Antarctica. However, compared with other matrices, there is a paucity of research examining plants including mosses, with existing studies primarily focused on the Antarctic Peninsula. Even within the limited research on metal accumulation in Antarctic mosses, most studies have employed bulk analysis methods, thus overlooking the potential for exploring high temporal and spatial resolution information on metal accumulation. This is largely due to the destructive extraction methods and large quantities of material necessary. In this study, we employed innovative and non-destructive synchrotron beamline-based X-ray fluorescence microspectroscopy techniques to scan entire moss shoots of the endemic moss species Schistidium antarctici collected from ASPA135 and ASPA136 in the Windmill Islands, East Antarctica. Sample ages were determined using radiocarbon dating techniques. Our results indicate that mosses accumulate metals along their shoots, with 18 metals detected in the samples. Furthermore, timing of the accumulation of some metals, such as Mn, Fe, Sr and Ti, coincided with the occurrence of anthropogenic activities around Casey Station. Thus, our research may provide a method for mapping metal accumulation with high temporal and spatial resolution along moss shoots. These methods should enable us to quantify past effects of human activities on Antarctic vegetation and provide theoretical basis for advice on waste management for the future.

933

On the smoothing of the total air content record in the deepest section of the Vostok ice core

Natalia Tebenkova^1,2, Viktoria Khomiakova¹, Vladimir Lipenkov¹, Andrey Salamatin¹

¹Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation. ²St. Petersburg State University, St. Petersburg, Russian Federation

Abstract

The strong anti-correlation observed between the total air content (TAC) records in central Antarctic ice cores and local summer insolation makes TAC a useful orbital dating tool for constraining the chronology of these cores, and possibly that of future ice cores which are anticipated from ongoing and planned oldest ice projects. We measured TAC in a fresh ice core from the new branch-hole 5G-5 drilled at Vostok Station in 2018-2024 as part of the Vostok Oldest Ice Challenge initiative. The TAC data discussed here were derived using the barometric method from stratigraphically disturbed meteoric ice bedded between 3463 and 3538 m and dated back to 600-1200 ka BP. The new measurements show an almost identical mean value of TAC to that of the upper section of Vostok ice, deposited 5-420 ka ago, suggesting that during the last 1.2 million years, the ice-sheet surface elevation in this part of East Antarctica has been essentially stable and similar to that which prevailed during the last 420 ka. However, the amplitude of the TAC variations in the old ice was found to be 2-3 times smaller than in the upper section of the ice core. We demonstrate that the observed attenuation of the orbital signal in the Vostok TAC record results from a combination of submetric ice mixing and diffusive smoothing, the two processes that become especially active near the base of the ice sheet. We also show that, in the absence of ice mixing, the amplitude of TAC variations in precession and obliquity frequencies would have undergone only minor diffusive smoothing, implying that TAC may still prove useful for dating very old undisturbed ice.

This study was carried out with the financial support from Russian Science Foundation, grant 23-27-00447

934

Antarctic contribution to the global program of IUGS Geological Heritage Sites: recent advances and perspectives

Dr Enrique Díaz-Martínez¹, Dr Anne Grunow², Dr Cliff Atkins³, Dr Luis Carcavilla¹, Dr Jerónimo López-Martínez⁴

¹IGME-CSIC, Madrid, Spain. ²OSU, Columbus, Ohio, USA. ³VUW, Wellington, New Zealand. ⁴UAM, Madrid, Spain

Abstract

The International Union of Geological Sciences (IUGS) sets globally-recognized geostandards through international scientific collaboration. With respect to the identification of geological heritage of international relevance, the International Commission on Geoheritage (IGC) of IUGS adopted in 2021 the global standards for the recognition of IUGS Geological Heritage Sites (GHS), and is currently developing the systematic inventory of GHS following the methodology recently developed and tested by UNESCO-IUGS IGCP project 731 (2021-2023).

SCAR has worked on the identification of Antarctic geological sites of exceptional value to be designated as IUGS GHS. In a first phase, and following the methodology developed by ProGEO and IUGS in the 1990s for the Global Geosites programme, the Action Group on Geological Heritage and Geoconservation, established by SCAR in 2014, identified the nine globally-relevant geochronologic intervals best representing Antarctic geological evolution, known as geological frameworks (GFs). To test the methodology in Antarctica, the mentioned Action Group initiated the identification of those sites better representing the features and processes of international relevance for one of the nine GFs, achieving in 2020 the identification of a first Antarctic GHS: the Cretaceous-Paleogene transition at Seymour / Marambio Island. This GHS was proposed as one of the “First 100 lUGS GHS” finally approved and officially designated by IUGS in 2022.

Since its establishment in 2022, the SCAR Expert Group on Geological Heritage and Geoconservation (EG-GEOCON) has continued this work. During 2023 and 2024, the EG-GEOCON is focusing on three other Antarctic GFs: Archean cratons (GF1), Cenozoic glacial history (GF6) and Meteorites and evidence of impacts (GF7). The peculiarities of geoscientific research in Antarctica, with less than 1% of the continent’s rocks exposed, pose several challenges for proper development of IUGS IGC standards, including reconsideration of GHS as sea level rises and more geological features are unveiled with glacial retreat.

936

Looking beyond the visible: radiometric thermal images as an ally for analyzing subpolar areas

Isabelle de Angeli Oliveira¹, Clara Glória Oliveira Baldi¹, Cássio Marques Moquedace¹, PhD Rafael Gomes Siqueira¹, Full professor Fábio Soares de Oliveira², Full Professor Márcio Rocha Francelino¹, Full Professor Elpídio Inácio Fernandes Filho¹, Full Professor Carlos Ernesto Gonçalves Reynaud Schaefer¹, Full Professor Carlos Ernesto Gonçalves Reynaud Schaefer¹

¹Federal University of Viçosa, Viçosa, Brazil. ²Federal University of Minas Gerais, Belo Horizonte, Brazil

Abstract

High-resolution thermal imaging can help study Antarctic environments and monitor climate change. We conducted an analysis to evaluate the potential of thermographic data in the pedogeomorphological characterization of sub-polar environments. The study area was the Stenhouse Peninsula. For imaging, we used a Zenmuse XT S thermal camera carried by a Matrice 300 RTK remotely piloted aircraft. We processed the images using Pix4D software, generating a radiometric thermographic mosaic. We observed that lower terrain environments, such as marine terraces, have the highest thermographic response values. These environments are characterized by the presence of exposed soil, rock outcrops and vegetation, elements that influence the presence of heat on the surface, given their ability to absorb radiation and emit heat. The lowest values were related to the high and concave slopes of the relief, areas with less exposure to the sun and wind, where the niches of nivation are established and influence lower surface temperatures due to the high level of albedo that the snow presents. Areas where liquid water occurs or accumulates corresponded to average values, distinguishing them from other environments and allowing for the identification of paraglacial lakes and drainage routes from the glacier and from gully niches. In glaciers specifically, the variability of the thermographic response is related to the degree of preservation of the edge of the ice field. In crevasses, where the subglacial deposits and the rocky substrate under abrasion are exposed, there was a greater thermographic response than areas where the ice cover was preserved. The results show that the use of thermographic sensors has great potential for pedogeomorphological characterization in sub-polar regions, glaciers and their respective ice-free areas in Antarctica.

937

Metagenomics reveal links between pro- and eukaryotic microbial communities, iron cycling and primary production across a latitudinal gradient in the Southern Ocean.

Dr. Hermanni Kaartokallio¹, Dr. Igor Pessi¹, Dr. Eeva Eronen-Rasimus¹, Dr. Lumi Haraguchi¹, Dr. Letizia Tedesco¹, Dr. Kristian Spilling¹, Dr. Harri Kuosa¹, Prof. Marcello Vichi², Assoc. Prof. Sarah Fawcett²

¹Finnish Environment Institute, Helsinki, Finland. ²University of Cape Town, Cape Town, South Africa

Abstract

In the World Ocean, iron (Fe) is one of the most important micronutrients for phytoplankton. Iron limitation is widespread in the open ocean with impacts on primary productivity, algal community structure and ultimately large-scale ecosystem processes. It is also considered to be responsible for the vast low production regions with high macronutrient concentrations in the open Southern Ocean (SO) regime. Iron availability in SO varies by distance from continents, i.e. reach of aeolian transport as well as presence of sea ice, which has been found to be an important modulator of iron availability.

Dissolved iron is accessible to microorganisms and bioavailable iron is almost completely bound to organic ligands or sequestered in oxide minerals. In offshore waters bacteria and archaea contain most of the biogenic iron and are responsible for up to 50% of the Fe uptake by the plankton community. Bacterial strategies to cope with iron limitation by uptake and storage traits vary with the environment and can be an important modulator of their iron content. Iron can be available for upper trophic levels through mixotrophic phytoplankton which feed on bacteria and simultaneously photosynthesize. Also the contribution of mixotrophic plankton is known to vary across latitudinal gradients in the SO.

We present results from microbial pro- and eukaryotic metagenomes collected across a gradient from subtropical zone to seasonal sea ice zone in the SO during South African SCALE-WIN22 winter research cruise. Both pro- and eukaryotic community compositions reflect the biogeographical zones and support the notion of variable metabolic potential in differing environments. Specific bacterial iron acquisition and storage traits across the gradient and in connection to shifts in mixotrophic primary producers will be elucidated and discussed.

938

Petrology of Granitoids from Queen Mary Land, East Antarctica, and their Implications for the Tectonic Evolution of Indian-Australian-Antarctic Counterparts of Gondwana.

Nikita Borovkov¹, Dr. Evgeniy Kunakkuzin², Dr. Tamara Bayanova², Alexander Golynsky¹, Dmitry Golynsky¹, Dr. German Leitchenkov¹

¹All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean" (FSBI "VNIIOKEANGEOLOGIA"), Saint-Petersburg, Russian Federation. ²Geological Institute, Kola Science Centre, Russian Academy of Sciences, Apatity, Russian Federation

Abstract

Late Neoproterozoic granitoid intrusions outcrop on Queen Mary Land’s places free of ice: Mirny Oasis, Gillies Nunataks, Hippo island, Delay Point escarpment, Cape Kennedy and David Island, i.e. the area expanding from Mirny Oasis eastwards until western side of Denman Glacier. According to investigations have being done the area represent the junction of Great Indian, East Antarctic and Australian continental landmasses during the assemblage of Gondwana supercontinent at ca. 550-530 Ma. Among mentioned outcrops we include syn-orogenic (anataxis-related, sills) small intrusion within Mesoarchean migmatized TTG complexes of Davis and Charcot Penninsulas. Our aim is possible reconstruction of geodynamic settings of Western Gondwana assemblage time by employing geochemical, particularly, stable and radiogenic isotopes fingerprints of granitoids occurred at different stages of the orogeny. Obtained geochronology (U-Pb, zircon, SHRIMP) indicates at least three phases of granitoid magmatism: (1) ca. 540-530 Ma, syn-orogenic, anatectic, intrusions and sills, migmatitic leucosomes (Charco and Davis peninsulas); (2) ca. 520 Ma early post-orogenic intrusions (Gillies Nunataks, Hippo island, Cape Dalay Point, Cape Kennedy, Mirny oasis); (3) ca. 480-510 Ma late-postorogenic transitioning to epeurogenic intrusions (Haswell island intrusion of Mirny Oasis; David Island bartholith and different aplitic late dikes cross-cuting intrusions on all locations). As a result, geochemical fingerprints including stable and radiogenic isotopes data indicate the predominance of crust material in the source of syn-orogenic phase and gradual increasing of mantle component in the source for early and late post-orogenic intrusions. Presumably, post-orogenic intrusions may be related to the effect of subducting slab and subsequent delamination process which provide geochemival fingerprints of matle source (A2-type) affected by subduction zone fluids and envolved crust material.

940

Unraveling the impact of soil microbial composition on metal transformation and metabolic dynamics along the glacier retreat gradient in King George Island

Dr. Ignacio Jofré-Fernández^1,2, Dr. Carolina Merino-Guzmán², Dr. Francisco Nájera-DeFerrari^1,2, Evelyn Ibarra²

¹Scientific and Technological Bioresources Nucleus, BIOREN, Universidad de La Frontera, Temuco, Chile. ²Laboratory of Geomicrobiology, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile

Abstract

The advancement of climate change has led to glacier retreat, particularly noticeable in the Antarctic Peninsula. This exposes large areas of soil, initiating soil formation processes and triggering the release of greenhouse gases. The objective of this study was to investigate soil carbon sources, microbial composition, and soil metal transformation along the glacier retreat on King George Island. Soils were analyzed in two chronosequences, with four sampling points each, from Domo Bellingshausen on Fildes Peninsula. Levels of C, N, and organic matter quality were measured, along with Fe II and III and Mn III metals through colorimetric reactions. Microbial distribution was determined through massive sequencing (Nanopore), and the consumption of ten carbon sources was assessed using the MicroResp system. Soils exhibited low organic matter content, high mineral content, and low polysaccharide quantities, indicating low microbial carbon input. However, labile sources such as acetate and fumarate were rapidly consumed in soils near the glacier, while glucose and fructose were most utilized in distant soils. An increase in Fe(III), Mn(III), and total Fe levels was observed in more distant zones, potentially enhanced by biotic and abiotic O₂ oxidations. Acidobacterium and Actinomycetes were the most representative phyla in the soil, indicating colonization by aerobic microorganisms stimulating oxidative activities in the soil. In conclusion, prolonged soil exposure increases mineral and organic matter oxidation by microorganisms, where soils farther from the glacier, with greater microbial maturity, exhibit metallic levels indicative of the development of the iron and manganese biogeochemical cycle.

942

POLAR EDUCATION STRATEGIES FOR THE STATE OF RIO GRANDE DO SUL, BRAZIL

PhD Carina Petsch^1,2, PhD Luiz Felipe Velho³, PhD Katia Kellem da Rosa⁴, Beatriz da Silva França¹, Janine Borges Fernandes¹, PhD Jefferson Cardia Simões⁴

¹Universidade Federal de Santa Maria, Santa Maria, Brazil. ²Centro Polar e Climático, Porto Alegre, Brazil. ³Instituto Federal do Rio Grande do Sul, Porto Alegre, Brazil. ⁴Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Abstract

In 2022, the Brazilian Antarctic Program celebrated its 40th year of research, contributing to our understanding of various topics, including glaciology, geomorphology, fauna, flora, and climate. However, concerning polar education and scientific dissemination, strategies must be expanded to bring this research closer to the school community and society. This work presents the outcomes of polar education practices conducted in Rio Grande do Sul (RS), the southernmost Brazilian state, with elementary school students. The methodology consists of two stages: (i) a theoretical debate with students using research, photographs, and videos from Brazilian researchers and (ii) practical activities such as drawing, mapping, and more. Since 2014, didactic workshops have shown that students are interested in the topic and actively participate in discussions, as it is often their first contact with the continent. However, regardless of their educational background, participants may have a superficial understanding of the continent or provide inaccurate information. In the case of RS, few students realize that the Antarctic Polar Mass causes cold waves in the southern hemisphere during winter. Because most Brazilian textbooks do not address Antarctica at all, it is common for students to have a greater understanding of certain aspects of the northern hemisphere due to the availability of films and television shows. The workshops produced positive results, with students improving their knowledge of the continent. However, there is still a need for actions that reach more students and stay in schools for longer periods to popularize Antarctic research throughout the state.

944

Satellites from space, drones from air, and fieldwork on ground: Identifying suitable sites to establish a research base in Eastern Antarctica

Dr Shailendra Saini¹, Dr Shridhar D Jawak², Dr. Prashant H Pandit³, Mr Sagar F Wankhede⁴, Mr Mirza Javed Beg¹

¹National Centre for Polar and Ocean Research, Vasco da Gama, India. ²Atmosphere and Climate Department, The Climate and Environmental Research Institute, Kjeller, Norway. ³Department of Information Engineering and Computer Science, University of Trento, Trento, Italy. ⁴Dept. of Civil Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, India

Abstract

On a warming white continent, continuous monitoring of the environment is crucial for enhancing scientific understanding of climate change. Spatially distributed investigations are necessary to facilitate continuous and improved analyses, requiring support from both long and short-term research bases across Antarctica. However, selecting potential sites for developing such bases in Antarctica is challenging, considering logistical, economical and weather constraints. Moreover, selecting sustainable sites to reduce the environmental and human footprint of science is the need of the hour. This study illustrates the applicability of remote sensing for selecting sustainable and suitable sites to establish temporary bases around the Lambert Glacier-Amery Ice Shelf (LAIS) system in East Antarctica. Site suitability assessment was performed utilizing openly available Earth observation data, unmanned aerial vehicles data, and data obtained during the 39^th Indian Scientific Expedition to Antarctica (39-ISEA) fieldwork. All datasets were incorporated within a geographic information system to identify around 21 potential temporary base sites, selected based on logistical and scientific considerations of Indian field expeditions in Antarctica.The site suitability analysis used a multi-criteria statistical evaluation, considering the aim of the future scientific research plan, logistic convenience, ease of transport from Bharati station, reducing fuel consumption, crevasses and distribution, distance from the coast for possible transport from the expedition vessel, topographical constraints, and meteorological observations. Thematic maps based on selected criteria were standardized and validated against observations made during field visits to potential sites. Lastly, this study provided suitable sites in the LAIS region, where a temporary field hut and helipad were installed, including a fuel dump site for supporting helicopter operations. The identified site, operational in summer, facilitated the 41-ISEA. In the future, this study will provide a mechanism for using EO data to select potential research base sites in Antarctica, promoting world-class science from Indian scientists for decades to come.

945

The Cretaceous-Paleogene boundary in Antarctica (Seymour Island): A preliminary micropaleontological and geochemical assessment

Rodrigo do Monte Guerra^1,2, Guilherme Krahl¹, Daiane Ceolin¹, Bruna Poatskievick-Pierezan¹, Marlone Heliara Hunnig Bom¹, Karlos Guilherme Diemmer Kochhann^1,3, Leslie Manríquez⁴, Rodrigo Scalise Horodyski^1,3, Gerson Fauth^1,3

¹Instituto Tecnológico de Paleoceanografia e Mudanças Climáticas (itt OCEANEON), São Leopoldo, Brazil. ²Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil. ³Universidade do Vale do Rio dos Sinos (UNISINOS), São Leopoldo, Brazil. ⁴Instituto Antártico Chileno, Punta Arenas, Chile

Abstract

The Cretaceous/Paleogene (K/Pg) boundary is one of the most studied intervals of Earth’s history. On Seymour Island (Antarctica), there is the Filo Negro section, considered as the most expanded K/Pg record from southern hemisphere. Herein we present micropaleontological and geochemical data from a 15 meters-long section, aiming to reconstruct paleoenvironments before and after the K/Pg boundary. We collected all fossils larger than 250 µm, and correlate their occurrences with sedimentary geochemical proxies, such as Ir (extraterrestrial impact) and Hg (vulcanism activity) concentrations, Ba/Fe (primary productivity), V/Cr (paleoxygenation), and Ca/Fe (terrigenous input versus carbonate production) ratios. Throughout the section, carbonized plant fragments were recovered, suggesting the record of paleofires. The classic K/Pg Ir anomaly was observed at 9.7 meters, accompanied by an increase in siderophile elements. However, previous study on the dinoflagellate biostratigraphy has recorded the K/Pg boundary between 9.5 and 9.6 meters. Additionally, we observed two Hg anomalies, the first ~1.2 meters below the K/Pg, and the second ~0.40 meters above it. Foraminifera (benthic and agglutinate) are abundant and occur consistently from the base of section up to 8.6 meters (~1 meter below the K/Pg). The Ca/Fe ratio declines from ~1.7 meters below the K/Pg to ~0.50 meters above it, where microfossils abundances drop and fish teeth occur. Primary productivity conditions follow the Ca/Fe trend, recording a slight drop of the Ba/Fe ratios ~1.7 meters below the boundary. During the earliest Danian, despite a slight recovery of productivity and calcium production, any of the studied proxies reached the values observed during the Cretaceous. Our preliminary results also showed predominantly dysoxic conditions, based on V/Cr ratio, with improved oxygenation in the 8.4 to 10 meters interval, which coincides with the highest occurrences of fish remains. Next steps will focus on recovering smaller microfossils, and mineralogical analyses emphasising the main palaeoenvironmental changes in the interval between the two mercury peaks (8.4 to 10 meters). [PROANTAR: 442676/2018-2]

947

25 years of glacial retreat on Vega Island, Northeast Antarctic Peninsula

Lic. Liliana Margonari^1,2,3, Doc. Carla Puigdomenech¹, Ing. Sebastián Marinsek¹

¹Instituto Antártico Argentino, Gral. San Martín, Argentina. ²CONICET, CABA, Argentina. ³Univerdad de Buenos Aires, CABA, Argentina

Abstract

Vega Island (-63.85,-57.40; 253.57 km2), northeastern Antarctic Peninsula, has experienced an ice loss during the last decades. From available optical satellite images obtained from Landsat program, the glacier ice area difference obtained from 1977 to 2023 was -40.45 km2 for the whole island. We observed that Cabo Lamb glacier, located on the south slope of the island, was retreating since the first image available from 1977 and then, this retreat was accelerated in the last few years. From 1977 to 2017 the glacier front retreated 470 m, which means 23.5 m/y, and from 2017 to 2022 the glacier front retreated 210 m, which means 42 m/y. From 2022 to 2023, only one year, the glacier front retreated 65 m. The continuous retreat since 2011 led to a new frontal lake started to form with an current area of ~0.17 km2. Besides the glacier front retreats, high resolution DEM Pleiades were processed and a geodetic mass balance was obtained for Cabo Lamb glacier between 2017 and 2022, yielding a total loss of -1.8 m w.e. As glacier mass balance is primarily controlled by temperature, with a direct relationship between the sum of positive degree days and ablation, from an automatic weather station installed nearby Bahía del Diablo glacier (on the north slope of the island) it has been observed that 2022 hydrological year presented the highest sum of positive degree temperatures (481°C) since 1999, with 2023 being the second highest record (444°C).

948

Two-position HF Doppler ionospheric sounding with active ionosonde at the Akademik Vernadsky Ukrainian Antarctic station and passive one aboard RV Noosfera

Dr Andriy Zalizovski^1,2,3, Prof Yuri Yampolski², Prof Iwona Stanislawska³, Dr Oleksandr Koloskov^1,2,4, Mgr Oleg Budanov², Dr Oleksandr Bogomaz^1,5, Mgr Bogdan Gavrylyuk^1,2, Dr Andriy Sopin^1,2, Mgr Artem Reznychenko^2,3, Dr Anton Kashcheyev⁴, Dr Sergiy Kashcheyev², Mgr Volodymyr Lisachenko²

Abstract

Ukrainian research vessel (RV) Noosfera is operating over three seasons in Antarctica (2022-2024). Before her first voyage to Antarctica, we equipped onboard radio observatory with passive ionosonde and 2-channel Doppler HF receiver. The paper focuses on the ionospheric effects observed using those tools.

Firstly, we present some results collected during the severe geomagnetic storm that occurred on April 23, 2023. Our case study covers the initial hours of this event illustrating how the geomagnetic storm affects long-distance ionospheric HF propagation. Following the onset of the storm, the last occurrence of an oblique trace on the ionogram was registered when the RV Noosfera was approximately 4700 km away from the active ionosonde. Concurrently, signals from the CHU station (Ottawa, Canada) at 7850 and 14670 kHz were observed at receiving sites at Akademik Vernadsky station and aboard the RV Noosfera during a short period when they were absent before and after the storm. It seems, that the redistribution of the ionospheric plasma in space led to the formation of HF radio propagation channels that are absent under quite conditions.

Secondly, we demonstrate the cases of middle scale travelling ionospheric disturbances (MS TIDs) observed over the South Atlantic Ocean using HF Doppler technique with receivers aboard the RV Noosfera. The most pronounced quasi-periodic variations in Doppler frequency shift associated with MS TIDs were registered when the RV Noosfera was located inside a deep active cyclone, which could be a source of atmospheric gravity waves impacting the ionosphere.

Thirdly, we present the results of oblique ionospheric sounding between Akademik Vernadsky Ukrainian Antarctic station and the RV Noosfera when she stayed at the Admiralty Bay in close vicinity of the Henryk Arctowski Polish Antarctic Station, for 4 days in April 2023. The prospects of using a similar scheme for long-term observations will be discussed.

949

Trace Gas Dynamics in the Changing Environment of the Western Antarctic Peninsula: Insights from a Field Campaign at Maxwell Bay, King George Island

Lina A. Holthusen¹, Prof. Dr. Oliver Wurl¹, Dr. Thomas Badewien¹, Prof. Dr. Hermann W. Bange², Isabell Schlangen³, Dr. Juan Höfer⁴, Dr. Damian L. Arévalo-Martínez⁵, Dr. Carolin Löscher³, Dr. Jens Meyerjürgens¹

¹Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky Universität Oldenburg, Wilhelmshaven, Germany. ²GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. ³Department of Biology, NordCEE, University of Southern Denmark, Odense, Denmark. ⁴Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. ⁵Department of Microbiology, Radboud University, Nijmegen, Netherlands

Abstract

The Western Antarctic Peninsula (WAP), a key region of the Southern Ocean (SO), is strongly affected by climate change, leading to changes in atmospheric and oceanographic processes. These include shifts in hydrodynamic properties, air-sea interactions, and marine primary productivity. These processes influence the regional dynamics of climate-relevant trace gases such as methane (CH₄) and nitrous oxide (N₂O), and their air-sea fluxes. Because of their role as greenhouse gases, a better understanding on air-sea transfer of CH₄ and N₂O in the SO will help to improve global climate models.

During a field campaign at the research station Base Julio Escudero on King George Island from December 2023 to January 2024, we collected discrete samples of CH₄ and N₂O in the water column at a fixed time series station in Maxwell Bay. In addition, we collected water samples from the sea-surface microlayer (SML) for surface active substances (SAS), which are known to influence the gas transfer across the SML. Trace gas samples were analyzed by gas chromatography and SAS samples were analyzed by voltammetry. The results are evaluated in combination with the hydrodynamics (surface currents, stratification) and meteorological forcing to estimate air-sea gas exchange rates.

Additionally, water from the SML and the underlying water was incubated in quartz glass vials with high transmissivity of UV- and solar radiation to assess the photochemical and microbial production or consumption of trace gases and SAS.

This research aims to contribute to the knowledge of distributions, production/consumption pathways, and exchange fluxes of CH₄ and N₂O in the WAP. The results of this study will not only improve the understanding of regional trace gas dynamics, but may provide insights for future research, addressing the importance of these gases for the global climate.

951

Description and comparative genomics of Streptomyces ANT1 sp. nov isolated from marine sediment from Maxwell Bay in Antarctica.

Raul Mauricio Olaechea Alejo, Ulrike Inge Tarazona Janampa, Wilbert Serrano Huiñocana

Universidad Científica del Sur, Lima, Peru

Abstract

The genus Streptomyces is well known as a group of microorganisms capable of producing multiple secondary metabolites. Pathway for Biosynthetic compound production is encoded within their genomes in the form of biosynthetic gene clusters (BGCs). Streptomyces strains have been poorly isolated from marine sediments in Antarctica, where metabolic adaptations influence survival under extreme conditions. Strain ANT1 was isolated in Glucose Asparagine Agar (GAA) from marine sediment samples collected from Maxwell Bay in King George Island during the 25th Peruvian expedition to Antarctica (ANTAR XXV). The taxonomic description of the strain was clarified by a polyphasic approach which includes genome comparison. Phylogenetic analysis based on the 16S rRNA gene sequences analysis showed that strain ANT1 belonged to the Streptomyces genus and was close related to S. diacarni, S. sclerotialus, S. iconiensis, and S. zangrosensis; however, strains of these species have not yet been isolated from Antarctica. Chemotaxonomic analysis revealed that predominant menaquinones were MK-9(H6/H8), and major fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. Production of antimicrobial compounds was evaluated, showing activity against Gram-positive bacteria and fungi. PacBio long-read sequencing was used to obtain the assembled genome of strain ANT1 (7.7 Mb). Digital DDH (66.4%) along with differences in phenotypic characteristics to the closest type strains suggested strain ANT1 can be a novel species. The annotation of ANT1 genome resulted in the identification of 24 BGCs mainly corresponding to terpene, lanthipeptide, siderophore, non-ribosomal peptide synthetase (NRPs), and polyketide synthase (PKS) gene clusters. Furthermore, BGCs from all available genomes of other antarctic Streptomyces strains were also annotated and compared to the strain ANT1.

956

Results of annual marine debris surveys at Fildes Peninsula, King George Island, Maritime Antarctic between 2019 and 2024

Christina Braun¹, Hannes Grämer¹, Fritz Hertel²

¹Polar & Bird Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Jena, Germany. ²Federal Environment Agency, Section II 2.3 Protection of the Seas and Polar Regions, Umweltbundesamt / German Environment Agency, Dessau-Roßlau, Germany

Abstract

The Antarctic is not excluded from the rapidly increasing global spread of marine debris in the oceans. The west coast of the Fildes Peninsula, King George Island is exposed to the Drake Passage and is therefore directly exposed to the influences of the surrounding ocean. As part of a study on the occurrence of marine debris, all visible objects with the exception of wooden objects that were washed up on the beach, were collected from a selected section of beach and classified according to the methodology recommended by CCAMLR. This provided valuable information on the type, quantity and, in some cases, the origin of the collected objects. The vast majority of the finds were plastic objects, including a significant proportion related to the fishing industry. At up to 0.85 objects/m of the coastline, the amount of marine debris washed up each year was higher than the values reported from other areas of the Antarctic. Microplastic particles were also found, including industrial primary plastic and biofilters from wastewater treatment plants. The latter have so far only been detected on the coasts of the northern hemisphere.

957

Development of a semi-persistent floating terminus at San Quintín glacier (Northern Patagonia Icefield), the last piedmont glacier lobe in the Andes

Michal Petlicki^1,2, Andres Rivera³, Jonathan Oberreuter⁴, Jose Uribe⁴, Johannes Reinthalter⁵, Francisca Bown⁶

¹Departamento de Geografia, Universidad de Concepcion, Concepcion, Chile. ²Faculty of Geography and Geology, Jagiellonian University, Krakow, Poland. ³Departamento de Geografia, Universidad de Chile, Santiago, Chile. ⁴Centro de Estudios Cientificos, Valdivia, Chile. ⁵University of Zurich, Zurich, Switzerland. ⁶Laboratorio de Glaciologia, TamboAustral Geoscience Consultants, Valdivia, Chile

Abstract

Glacier fronts are retreating across the globe in response to the effects of climate warming, thereby revealing valleys, fjords, and proglacial lakes. The piedmont lobe of San Quintín, the largest glacier of the Northern Patagonia Icefield, in southern Chile, has lately entered a phase of frontal retreat, where its terminus is rapidly disintegrating calving large tabular icebergs into a recently formed proglacial lake. We present results from a 2019 airborne GPR survey conducted at the terminus of this large Patagonian glacier (763 km² in 2017). This survey, coupled with an analysis of ice flow velocity, satellite imagery, and ice elevation change, reveals that the current retreat can be attributed to the recent detachment of a floating terminus from the glacier bed. Consequently, it is imminent that the last remaining piedmont lobe in Patagonia may vanish in coming decade. Finally, we discuss how the observations of San Quintín’s ongoing collapse offer valuable insights into the mechanisms governing the frontal retreat of fast-flowing temperate glaciers similar to those of Antarctic Peninsula, as well as the quasi-stability exhibited by their floating termini.

958

Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica

Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Yaroslav Gribik, Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Radim Garetsky, Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Oleg Myasnikov, Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Robert Girin, Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Sergey Sushkevich, Belarusian geological studies of the earth's crust Vechernegorskaya area, Enderby Land, East Antarctica Pavel Shablyka

Institute of Nature management National Academy of Science of Belarus, Minsk, Belarus

Abstract

Over the 15-year period of operation of the seasonal Belarusian Antarctic Expeditions, geological research was aimed at regional geological study of the areas where Archaean-Proterozoic bedrock emerged.

Geological formations from the oldest Archean to modern glacial ones have been encountered on Vechernegorskayaarea. According to structurally tectonic conditions, four main petrographic heterogeneities inherent in the dominant processes of tectonothermal activation of four geochronological boundaries, including Early and Late Archean and three stages of Early and Late Proterozoic (Grew E.S., 1978,1981; Mikhalsky E. et al., 2017).

Breeds of archaean age biotite-hornblende-diperoxene of the plagiogneiss having the subordinated distribution in a northern part of Vechernegorskaya area taking into account metamorphic "rejuvenation" is dated not more young than the Neoarchean. Plagiogneisses of Vechernegorskaya area have been preserved in the form of remains, xenoliths of primary igneous rocks.

Paleoproterazoic. Enderbitic strata. Enderbitesare encountered in the center and east of the territory. They form lenticular bodies with a thickness of 100-200 m on the southern and 50-100 m on the northern contacts with Archaean plagiogneisses. Mesoproterazoic represented by the Charnokite thickness. Temporal discretness of conditions for the manifestationoftectonothermal processes of the mesoproterozoic causes the processes of charnocitization– there is a transition from enderbites to charnockites. The Mesoproterozoic age of the enderbite-charnockitoid stratum is determined at various points in the territory. Charnockitoids occupy a dominant position in the structure of Vechernegorskaya area.

Neoproterozoic. Charnockite (hybrids) stratum of gneissic-rapakivi-like ultrametamorphic (leiko) granitoids. The completion of the development of charnockitization processes was the transition to granitization. The age of the Charnockite gneissic-rapakivi-like ultrametamorphic stratum corresponds to Neoproterozoic time (Myasnikov, 2011).

Granitoid vein-dyke complexes dissect the strata of gneissic-charnockites, as well as a series of discontinuous faults reflected in geophysical fields.

959

Non-breeding diet of gentoo penguins at Stranger Point/Cabo Funes, South Shetland Islands, Antarctica

Dr. Mariana A. Juáres^1,2,3, PhD Student Pablo J. Perchivale^1,3, PhD Student Mauro G. Rozas Sia^1,2,3, Dr. Rosana Sandler⁴, Dr. Ricardo Casaux⁵, Dr. M. Mercedes Santos^1,3, Lic. Marcela Libertelli¹

¹Instituto Antártico Argentino (IAA), San Martín, Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina. ³Facultad de Ciencias Naturales y Museo, La Plata, Buenos Aires, Argentina. ⁴Instituto de Ecología y Desarrollo Sustentable (INEDES), Luján, Buenos Aires, Argentina. ⁵Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET–UNPSJB), Esquel, Chubut, Argentina

Abstract

Understanding predator-prey relationships is essential for monitoring Antarctic marine ecosystem structure and function, assessing changes in predator abundance, and implementing effective conservation measures. However, diet studies of Antarctic predators using traditional methods are limited outside the breeding season due mainly to constraints associated with the life-history strategies of the predators and the logistics and operability of sampling. At Stranger Point/Cabo Funes (25 de Mayo/King George Island), we characterized the diet composition of non-breeding gentoo penguins (Pygoscelis papua) in May and August 2022 (n = 28) from the analysis of stomach contents obtained using the water-offloading technique. Antarctic krill (Euphausia superba) dominated the diet of gentoo penguins in terms of frequency of occurrence and percentage in mass (96.4% and 87.9%, respectively), followed by fish (78.6% by frequency and 11.9% by mass) and amphipods (39.3% by frequency and 0.2% by mass). Nothoteniids were the most important fish prey (64.3% of the 28 sagittal otoliths found, with larvae and juveniles predominant), while Themisto gaudichaudii was the most representative species of amphipod (81.8% by frequency). The mean krill length consumed by gentoo penguins during the austral autumn and winter of 2022 was 36.9 ± 9.8 mm (n = 1646, range: 8.1 – 57.1 mm), with a 32.5% of juvenile krill (i.e. ≤ 35 mm) and 15.2% of 1-year-old krill (i.e. ≤ 25 mm). Although gentoo penguins are opportunistic feeders, these results suggest that krill remain an important fraction of the non-breeding diet, similar to the breeding period. However, the mean krill size consumed was smaller and the proportion of juvenile krill was higher than that normally recorded in the chick-rearing period.

960

Update of the long-term seabird monitoring in the Fildes Region, King George Island, Maritime Antarctic

Hannes Grämer¹, Christina Braun¹, Fritz Hertel²

Abstract

The Fildes Region, King George Island, South Shetland Islands, is home to fourteen bird species, six seal species and a rich tundra vegetation. Data from a long-term monitoring program carried out since 1979/80 provides detailed information on population trends over the past decades. While Adélie and chinstrap penguins in the area have recorded a steady decline, the gentoo penguin population has increased considerably, making the colony on Ardley Island the largest colony of this species in the Antarctic. The local population of the Southern Giant Petrel, a species that had been negatively impacted by human activities, particularly the establishment of new Antarctic stations in the 1980s, has shown significant growth until today. Following the observed relocation of nesting sites to areas with less anthropogenic disturbance, several previously abandoned colonies have been reoccupied and the overall trend for this species is now positive. In contrast, the population of the two skua species present in the area shows strong variability, but no temporal trend over the decades. In contrast, the Cape Petrel population has declined dramatically and this species has almost completely disappeared from the area. Our long-term monitoring data are extremely valuable as they contribute to the knowledge of the development of seabird populations and the assessment of the influence of various environmental factors.

962

Instruments and Methods to Study Ice-covered Lakes in Antarctic Oases

Dr Da Gong¹, Dr Yazhou Li², Dr Xiaopeng Fan¹, Prof Nan Zhang¹, Dr Bing Li², Mrs Ting Wang¹, Mr Ximu Liu¹, Mr Wei Wu¹, Mr Tao Xian¹, Prof Pavel Talalay¹

¹Jilin University, Changchun, China. ²China University of Geosciences, Beijing, China

Abstract

Direct detection and sampling are crucial for the study of ice-covered lakes in Antarctic oases, including research on lake’s hydrology, microbial community, sedimentation characteristics and thermal conditions on the lake floor. We proposed a simple and serialized method to study such ice-covered water environment: i) full-diameter drilling tools to penetrate through overlying ice, ii) in-situ measurement and sampling of lake water, iii) underwater camera; iv) sediment sampling and temperature measurement. Instruments and methods were tested at the deepest point (47m water depth, 5m ice thickness) of Boulder Lake in Larsemann Hills, most technological equipment has proved efficient except for lake floor temperature measurements due to limitations of the surface equipment capabilities. Lake water vertical temperature distribution data, water sample and bottom surface sediment were obtained. The relevant technologies and methods will continue to be improved, especially in terms of feasibility and convenience of on-site operations.

966

Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica

Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Yaroslav Gribik, Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Robert Girin, Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Oleg Myasnikov, Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Pavel Shablyka, Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Sergey Sushkevich, Belarusian geophysical studies of the earth's crust of the Vechernegorskaya area, Enderby Land, East Antarctica Arthur Khibiev

institute of Nature Management National Academy of Science of Belarus, Минск, Belarus

Abstract

During the period of seasonal Belarusian Antarctic expeditions, geophysical research was aimed at regional tectonic study of bedrock outcrops. These included geomagnetic, radiometric, gravity, and kappametric surveys, accompanied in parallel by geological research. Stationary and field measurements were carried out along profiles and over the area of the region.

A geomagnetic study of the Mount Vechernyaya region was carried out using special equipment, which made it possible to study magnetic anomalies in the region in detail. The anomalous magnetic field in the ice – free areas of the coastal part of the Vechernegorskaya area is due to structural and material heterogeneities and fault-intrusive tectonics. Geomagnetic anomalies of different intensity and morphology indicate a different material composition of geological bodies.

Based on the results of surveying the Vechernegorskaya area, three geomagnetic zones were identified: Northern, Central and Southern, each of which has its own morphological picture and specific geomagnetic indicators. All three zones have a strip character with a northwestern strike.

Based on the results of continuous daily observations of magnetic field variations, the structure of the geomagnetic field and its relationship with the tectonic features of the geological section were determined.

Based on the results of cappametric studies, a map of the magnetic susceptibility of rocks was compiled, which determines the nature of geomagnetic anomalies.

Based on the results of the radiometric survey, the radiation field in the territory of Vechernegorskaya area and its surroundings was assessed in order to identify anomalies and their relationship with geological structures and rock types.

968

National Antarctic Museum – Trieste Section: Integrated Teaching Methods to Understand Environmental and Climate Changes

Ph.D Gianguido Salvi^1,2, Prof. Ester Colizza^1,2, Ph.D Ioanna Protpsalti^1,2

¹1- National Antarctic Museum – Trieste Section, Trieste, Italy. ²2- Department of Mathematics, Informatics and Geosciences, MIGE, Trieste, Italy

Abstract

The Italian education system currently shows difficulties in introducing the paradigm of sustainable education. The promoted curricula, while imparting significant content to students, do not appear to be adequate in reinforcing critical thinking. Biodiversity, environmental quality, and climate change are complex issues that require connecting articulated and seemingly isolated elements. To overcome the growing crisis of the "normal" model of knowledge, essentially based on the transmission of information, and to introduce an interdisciplinary logic necessary for connecting to the aforementioned issues, collaboration between educational institutions and various public and private entities external to the educational institution seems to be one of the most effective tools.

In this sense, the National Museum of Antarctica in Trieste employs integrated teaching methods to enhance understanding of environmental and climate changes. These methods have proven effective across primary and secondary schools. Primary school students have shown enthusiasm, particularly in interacting with magnetic panels. Sensory stimulation has been pivotal in fostering curiosity and participation, thereby amplifying the learning experience's impact. The role of play and enjoyment in education, often overlooked in traditional teaching, has become evident. Students' comprehension and retention of information have been evident during museum visits, highlighting the significance of these educational approaches. For secondary school students, the museum has facilitated an expansion of knowledge regarding the Earth's physical and geological characteristics, increased interest in environmental issues and climate change, improved research skills, and enhanced group work abilities.

In this current complex era, it's crucial to develop educational projects that awaken young people's consciousness, fostering an understanding of their potential and nurturing critical thinking. The museum's integrating teaching methods represent a significant step towards achieving these goals, providing a platform for students to explore and comprehend environmental and climate changes in a holistic and engaging manner.

970

Dynamic Interplay: How Food Web Dynamics can Influence Mercury Biomagnification in a Southern Ocean

José Seco¹, Paco Bustamante², Filipe Ceia³, João P. Coelho⁴, Ryan Saunders⁵, Ricardo Ricardo Matias⁶, Geraint Tarling⁵, José Xavier¹

¹University of Coimbra, Coimbra, Portugal. ²University La Rochelle, La Rochelle, France. ³UC, Coimbra, Portugal. ⁴University of Aveiro, Aveiro, Portugal. ⁵BAS, Cambridge, United Kingdom. ⁶CIMAR, Porto, Portugal

Abstract

Biomagnification of mercury (Hg) in the Scotia Sea food web of the Southern Ocean was examined using the stable isotope ratios of nitrogen (d¹⁵N) and carbon (d¹³ C) as proxies for trophic level and feeding habitat, respectively. Total Hg and stable isotopes were measured in samples of particulate organic matter (POM), zooplankton, squid, myctophid fish, notothenioid fish and seabird tissues collected in two years (austral summers 2007/08 and 2016/17). Overall, there was extensive overlap habitats. As expected d¹⁵N showed increasing enrichment across groups in the order POM to zooplankton to squid to myctophid fish tonotothenioid fish to seabirds.

Hg concentrations increased with trophic level, with the lowest values in POM (0.0005 ± 0.0002 mg g1 dw) and highest values in seabirds(3.88 ± 2.41 mg g1 in chicks of brown skuas Stercorarius antarcticus). In the mid trophic level species (squid and fish) , the Hg concentrations tended to be lower in 2016/17 than in 2007/08, but the opposite was found for top predators (i.e. seabirds), which had higher levels in the 2016/17 samples.
We suggest that this puzzling outcome, may reflect an inter annual shift in the Scotia Sea marine food web, caused by the reduced availability of a key prey species, Antarctic krill Euphausia superba. In 2016/17 low year of krill, the seabirds would have been forced to feed on higher trophic-level prey, such as myctophids, that have higher Hg burdens. These results suggest that changes in the food web dynamics can affect the pathway of mercury to Southern Ocean top predators.

972

Need of a geodetic core infrastructure to support interdisciplinary research at the Bulgarian Antarctic Base "St. Kliment Ohridski", Livingston Island

Dr Lyubka Pashova¹, Dr Borislav Alexandrov²

¹National Institute of Geophysics, Geodesy and Geography - Bulgarian Academy of Sciences, Sofia, Bulgaria. ²University of Architecture Civil Engineering and Geodesy, Sofia, Bulgaria

Abstract

The acquisition of accurate geodetic data is essential to supporting interdisciplinary research on Livingstone Island, South Shetlands Archipelago. Following the priorities of the Geodetic Infrastructure of Antarctica (GIANT) program of the Scientific Committee on Antarctic Research and the Bulgarian Antarctic Research program, creating a geodetic infrastructure to conduct long-term, high-quality scientific research has been initiated at the Bulgarian Antarctic Base (BAB) “St. Kliment Ohridski” on Livingstone Island. This work presents activities related to the gradual construction of precise geodetic infrastructure at the BAB, which started in 1998. It consists of establishing a ground GNSS station in 2019 and installing a tide gauge to monitor sea level change in 2017. The geodetic measurements, such as classical geodetic and GNSS observations, and initial mapping of the island's topography and the seabed are briefly described. The main results and achievements of the research conducted during the summer campaigns are summarized. Some problems regarding upgrading, maintaining, and improving specific elements of the geodetic stations are discussed, as well as the need to coordinate activities to ensure sustainable and long-term sea level research.

973

ICE DYNAMIC AND OCEANOGRAPHIC FLUCTUATIONS RECORDED IN COLLINS BAY SOUTH SHETLAND ISLANDS, ANTARCTIC PENINSULA

Adriana Tudurí¹, Laura Pérez², Rubens Lopes Figueira³, Paulo Alves de Lima Ferreira³, Luis Cerpa⁴, Wai Long Ng Cutipa⁴, Erick Cifuentes⁵, José Herrera⁴, Natalia Venturini¹

¹Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. ²Centro Universitario Regional del Este, Rocha, Uruguay. ³Instituto Oceanográfico, Universidad de São Paulo, San Pablo, Brazil. ⁴Instituto Geológico Minero y Metalúrgico, Lima, Peru. ⁵Departamento de Ciencias de la Tierra, Facultad de Química, Universidad de Concepción, Concepción, Chile

Abstract

Studies conducted on the Antarctic Peninsula have revealed that climatic conditions and ice dynamic in the late Holocene appear to be unstable and spatially variable due to the combined influence of global and local processes. With the aim of contributing to unraveling the late Holocene ice and oceanographic variability record in Collins Bay (King George Island), we analyzed a sediment core (GANT20-PC07; 181 cm-lenght) collected using a piston system on board the R/V BAP Carrasco (ANTAR XXVII-Cruise Orca II, 2019/2020) from the Peruvian Navy. A mixed age-depth model spanning the last 2200 years was constructed combining both ²¹⁰Pb and ¹⁴C dating. XRF analyses every 1cm were conducted on the core, and the Br/Ti, K/Ti, Rb/Sr, and Zr/Rb were used as proxies of productivity, physical and chemical weathering, and grain size variations, respectively. Diatoms analyses were performed in 21 sediment core sections and relative abundances of ecological groups previously used in the region (benthic, sea ice and open water related forms) were calculated. Paleoceanographic conditions during the last 2200 years in Collins Bay revealed climatic dynamics such as the Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA). Post-LIA, notable XRF changes appear to indicate that the culmination of the LIA likely led to a warming trend that extends to the most current records, characterized by an increase in meltwater flow and runoff, as evidenced by the rise in weathering proxies and reduction in grain size. Moreover, increase in benthic and open-water diatoms suggests conditions of heightened variability in sea ice. Such environmental conditions occur simultaneously with an increase in paleoproductivity indicators and have resulted in an increase in both the diversity and richness of diatoms. This study illustrates how climatic forces govern oceanographic shifts in Collins Bay, impacting both productivity and ice dynamics.

974

Continuous Determination of Seawater Isotopes in the Southern Ocean: Implications for Ocean warming-Induced Changes in Water Mass Mixing

Songyi Kim^1,2, Jangil Moon¹, Yeongcheol Han¹, Won Sang Lee¹, Jeonghoon Lee², Soon Do Hur¹

¹Korea Polar Research Institute, Incheon, Korea, Republic of. ²Ewha Woman's University, Seoul, Korea, Republic of

Abstract

Significant alterations in the Antarctic coastal region, driven by the accelerated melting of ice shelves and sea ice due to ocean warming, are freshening seawater and disrupting established salinity and water mass mixing patterns. Understanding these changes in real-time is crucial for refining numerical models. Improved models not only explain physical and chemical processes across local to global scales but also project future sea level rise. This study aims to develop a new observational method using seawater oxygen isotopes to capture these changes in real-time, thereby increasing the accuracy of numerical models. However, the spatial limitations of traditional sampling methods present significant challenges in comprehensively capturing these changes. This study aims to overcome these challenges by developing a new observational method using seawater oxygen isotopes to enable continuous and real-time determination of the seawater.

Our research introduces an advanced observational approach by employing continuous measurements of the seawater isotope ratio through laser spectroscopy. Especially in maritime observation, it’s necessary to employ methods of sampling that are adapted to the conditions of the vessel. Unlike current methods that use pumps to draw water samples, our system integrates a flow controller to regulate pressure, ensuring a consistent flow of samples into the analysis equipment. This enhancement facilitates more reliable and uninterrupted data collection, which is crucial for real-time determination in the challenging conditions of the Antarctic.

The research carried out aboard the Korea Polar Research Institute’s icebreaker Araon, occurred from January to February 2024 in the Amundsen Sea, Antarctica. By providing detailed insights into the mechanisms driving salinity, temperature, and ice melt, this approach significantly enhances our understanding of specific regional responses to rapid climate change. It contributes to a more nuanced assessment of how these factors influence local ice melt rates and their potential contribution to sea level changes.

976

Ornithogenesis shapes cover and richness of plants through soil chemistry in Lions Rump, Maritime Antarctica

Matheus Gonçalves Matos, Luisa Somerlate Sena, Mariana Cassini Lima, Daniela Schmitz, Rafael Siqueira, Flávia Ferrari, Carlos Schaefer

Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

The vegetation of Maritime Antarctica is mainly composed of mosses, lichens and two angiosperms, being influenced by birds’ activity, mainly penguin. This research was conducted in three slopes of Lions Rump promontory with different sea-facing aspects on King George Island, Maritime Antarctica. A1 is in the high part, facing northeast; A2 and A3 are situated at the base, facing south and northwest, respectively. In each area, a phytosociological survey was conducted, with 26 plots of 20x20 cm. Soil samples (0-10 cm) were collected for chemical analyses. The soil pH was acidic in all areas (~5). Organic matter (OM) content was higher in A1 (12.9 g/kg), while the lowest value was observed in A3 (3.7 g/kg). Phosphorus (P) levels followed the same pattern as organic matter, with average values of 1098 in A1 and 373 A3 (mg/dm3), respectively. Fe content was also higher in A1, with 672.6 (mg/dm3). Sodium was higher in A2 due to the beach proximity (862 mg/kg). All areas were dominated by the grass species Deschampsia antarctica Desv., with highest vegetation coverage in A1 at 94%, followed by A2 (93%) and A3 (88%). A2 exhibited the highest species richness (20 species), followed by A3 (10 species) and A1 (8 species). The highest values of OM and P in A1 is likely explained by the longer exposure to bird influence and guano deposition. In turn, the greater coverage of Deschampsia Antarctica is related to the creation of soils with unique chemical conditions (acid and high P content) that favor the development of better adapted plants. Data shows that birds play an important role in nutrient transfer from the ocean to terrestrial systems in Antarctica, enriching soil chemistry and contributing to the formation of vegetative hotspots with unique characteristics in composition and diversity.

978

Enhancing Antarctic Science Security: Implementing Article 2 of the 'Agreement on the Rescue of Astronauts' for Antarctic Operations

Magister Victoria Valdivia

European Space Policy Institute (ESPI), Santiago, Chile. ANEPE, Santiago, Chile

Abstract

The increasing tourism activity in Antarctic and sub-Antarctic areas is expanding the operational risk, impacting the environment, and undermining scientific activities in Antarctica from the security and safety perspective, diversifying their focus from scientific missions under the ATS to tourism activities not explicitly covered by the Antarctic Treaty.

Regarding the Antarctic Treaty System (ATS), there exists no binding norm that prioritizes scientists in Antarctica over tourist visitors. This absence of specific protection for permanent delegations conducting ATS activities could lead to international impasses among states operating in Antarctica. Due to their significance for multilateral governance in Antarctica, scientific activities under the ATS necessitate special consideration, as they are integral to processes such as transparency and confidence-building. Ensuring the security and safety of these activities is crucial for reducing the likelihood of conflicts among states. There is a pressing need to provide special protection to Antarctic delegations conducting scientific activities, akin to the treatment of astronauts in space governance, as they play a pivotal role in processes such as peace in outer space and the multilateral governance of space activities.

Consequently, this research, adopting a comparative case study methodology, will explore the application of Article 2 of the "Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space" derived from the Outer Space Treaty system (OTS) to the ATS, particularly to scientific delegations conducting activities under the umbrella of ATS on behalf of its foundational principles. Due to its novelty, this research is contributing with cutting-edge research by offering new insights to academia and international stakeholders to improve the resilience of international governance of Antarctic activities by addressing emerging hazards such as incidents with official state delegations and by distinguishing tourism activity from scientific activity.

980

Adapting feature-tracking methods to estimate velocity gradients of small, sparsely-featured alpine and outlet glaciers in the McMurdo Dry Valleys, Antarctica

Mia Vanderwilt^1,2,3, Dr. Michael Gooseff¹

¹Institute of Arctic and Alpine Research, University of Colorado, Boulder, USA. ²NASA Goddard Space Flight Center, Greenbelt, USA. ³Earth System Interdisciplinary Center, University of Maryland, College Park, USA

Abstract

In the ice-free regions of Antarctica, alpine and outlet glaciers are a significant source of meltwater to ephemeral streams, lakes, and oases ecosystems therein. Characterizing the flow and changing extent of these smaller glaciers can elucidate the physical controls on these water-limited regions and help describe how they are responding to environmental conditions. Image cross-correlation and feature tracking are commonly used to characterize ice sheet and glacier surface velocities from optical and radar datasets. These techniques rely on distinctive surface features – such as crevasses, large erratics or sastrugi – which can be tracked across pairs of temporally-offset imagery. Where features are well-resolved with respect to the imagery’s spatial resolution, and well-preserved relative to its temporal resolution, velocities can be derived with sub-pixel accuracy. However, cross correlation performance is poor where glaciers lack meaningful surface texture, a common occurrence for the low-gradient, frozen bed glaciers of the McMurdo Dry Valleys. Velocity estimates for these glaciers require high-resolution imagery to track minor features, such as cracks and small erratics, on otherwise smooth uncrevassed surfaces. Small alpine glaciers throughout Antarctic ice-free regions similarly require high-resolution imagery to resolve features at scales finer than that of surrounding ice sheet flows. Here we present adaptations of existing feature tracking methods and a novel combination of image preprocessing steps which enable feature tracking on these glaciers. Velocity estimates derived via this workflow are comparable to in situ measurements and contribute to a larger effort to utilize remote sensing to determine how glacier mass balance, thickness, surface roughness and meltwater runoff are dynamically evolving in Antarctica’s dry valleys.

982

Unveiling Soil Viral Diversity and Metabolic Potential in Antarctic Rhizosphere Biogeochemistry

Dr. Sergio Guajardo-Leiva, Mr. Valentín Berríos-Farías, Professor Eduardo Castro-Nallar

Universidad de Talca, Talca, Chile

Abstract

Viruses play a crucial role in shaping microbial communities across various Earth environments, with most of our knowledge coming from oceanic and model ecosystems. However, the ecological functions of viruses in soil and rhizospheres have remained mostly unexplored. Consequently, this study aims to investigate how bulk soil and plant rhizosphere environments influence the ecological and functional diversity of viral communities, particularly examining their potential impacts on plant fitness and biogeochemical cycles.

To address these objectives, we conducted viral and cellular metagenomic analyses in the rhizosphere of Deschampsia antarctica and Colobanthus quitensis, as well as in bulk soil, across two locations in the Byers Peninsula, Livingston Island, Antarctica. This comprehensive effort revealed 32,425 viral Operational Taxonomic Units (OTUs), representing viral genera absent from isolated representatives and environmental virus databases such as IMG/VR. Additionally, we annotated viral auxiliary metabolic genes (AMGs) using DRAMv, uncovering numerous Carbohydrate-Active enzyme sequences, notably glycoside hydrolases and polysaccharide lyases responsible for cellulose, hemicellulose, and pectin degradation.

Our findings demonstrate that plant species, compartments (rhizosphere and bulk soil), and edaphic soil properties significantly influence viral community ecological and functional diversity, as well as, the species turnover. Moreover, the outstanding number of vOTUs highlights the remarkable diversity and novelty within viral communities present in the rhizosphere and surrounding bulk soil of Antarctic vascular plants. Furthermore, the identification of AMGs involved in plant cell wall breakdown within viruses infecting bacteria underscores viruses' critical role in modulating carbon turnover in soils, thus emphasizing their pivotal contribution to the carbon cycle within both the rhizosphere and bulk soils.

983

Comprehensive Logistical Analysis Using Data for Improved Antarctic Operations (CLAUDIA).

Magister Victoria Valdivia Cerda

European Space Policy Institute, Santiago, Chile. ANEPE, Santiago, Chile

Abstract

An increasing number of Antarctic operations, conducted by various host countries, has highlighted the challenges of the Antarctic surface. Emerging threats and hazards to the security of these operations arise from a multidimensional perspective that extends beyond the established terms of the Antarctic Treaty System.

Simultaneously, the outer space dimension is experiencing a surge in activities, generating a substantial volume of remote-sensing data that enhances our understanding of Earth's phenomena and dynamics. This knowledge can evolve into practical applications to mitigate risks in various operations, including the development of Antarctic missions.

Given the complexity of operating in Antarctic territory, the preparation of the logistical aspects becomes a critical factor in reducing associated risks. However, phenomena such as climate change and the increased human capability to reach new latitudes within the continent (venturing south and beyond the South Pole) introduce new hazards to the security and safety aspects of operations. This situation even affects tourists as these types of operations become more prevalent.

Through a comprehensive analysis of how satellite-based data could enhance the logistical framework and improve the security and safety of Antarctic operations, this research aims to propose an analytical framework that would consolidate "Antarctic-Space Situational Awareness" as a new capability. This framework would serve as valuable input during the planning phase, emphasizing the benefits of outer space activities for Antarctic affairs and the necessity of regulation on emerging hazards like conflicts involving outer space activities. Due to its novelty, this research will contribute to international academia by offering cutting-edge insights for the future development of capabilities aimed at improving human security and safety in Antarctica

985

An evaluation of the Southern Annular Mode in the Twentieth Century Reanalysis

Dr Julie Jones¹, Dr Andrew Lorrey², Prof Ryan Fogt³, Dr Laura Slivinski^4,5, Dr Gilbert Compo^4,6, Dr Phillip Brohan⁷, Dr Nicolas Fauchereau⁸, Dr Gareth Marshall⁹

¹University of Sheffield, Sheffield, United Kingdom. ²NIWA, Auckland, New Zealand. ³Ohio University, Athens, USA. ⁴University of Colorado CIRES, Boulder, USA. ⁵NOAA Earth System Research Laboratory, Boulder, USA. ⁶NOAA Physical Sciences Laboratory, Boulder, USA. ⁷UK Met Office, Exeter, United Kingdom. ⁸NIWA, Hamilton, New Zealand. ⁹British Antarctic Survey, Cambridge, United Kingdom

Abstract

We explore whether improvements to the Twentieth Century Reanalysis (20CR) in the most recent version (v3) have improved representation of the Southern Annular Mode (SAM). The negative SAM index bias in the first half of the 20th century compared to instrumental SAM reconstructions in previous 20CR versions (due to a systematic high latitude high pressure bias) is still present. It is reduced in summer and autumn, but not in winter and spring. Correlations between reanalysis and reconstructed SAM indices through the full series in all seasons do show improvements in v3 compared to previous versions.

A reduction in SAM index ensemble spread is evident during periods with higher numbers of assimilated observations, in particular in summer and autumn. Analysis of the spatial distribution of assimilated observations shows clear improvement in years/periods with greater numbers of ships observations in the Southern Ocean and Antarctic observations (e.g. early 20th century Antarctic expeditions). However it is not until the advent of greater numbers of ships observations in the Southern Ocean and regular data from Antarctic meteorological stations in the late 1940s that there are enough high latitude observations to realistically constrain the reanalysis.

Enhancements have been enough to improve how the reanalysis follows the observations temporally, highlighting the benefit of data rescue, but due to the bias, we recommend that the 20CR should still not be used for the analysis of long-term SAM trends, and caution should be exerted when using SLP data from the high latitude Southern Hemisphere from all 20CR versions prior to 1957.

990

Wood borings produced by bivalves from the Eocene in Antarctica: Palaeobiological, taphonomical and paleoecological implications

PhD Jorge Villegas Martin¹, PhD Leslie M. E Manríquez², PhD Rodrigo Do Monte Guerra^1,3, PhD Gerson Fauth⁴, MSc Bruna Schneider⁵, PhD Rodrigo Scalise Horodyski⁵, PhD Karlos G Diemer Kochhann¹

¹Instituto Tecnológico de Paleoceanografia e Mudanças Climáticas – itt OCEANEON, Universidade do Vale do Rio dos Sinos-UNISINOS, São Leopoldo, Brazil. ²Laboratorio de Paleobiología de Antártica y Patagonia, Instituto Antártico Chileno (INACH), Punta Arenas, Chile. ³Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil. ⁴itt OCEANEON, Universidade do Vale do Rio dos Sinos-UNISINOS, São Leopoldo, Brazil. ⁵Universidade do Vale do Rio dos Sinos-UNISINOS, São Leopoldo, Brazil

Abstract

In this work, wood-borings assigned to Apectoichnus longissimus and Teredolites clavatus preserved in wood fragments are described for Eocene deposits of La Meseta Formation, Seymour Island, Antarctic Peninsula. In addition, their palaeobiological, paleoecological, and taphonomic implications are discussed. Apectoichnus longissimus features (long, sinuous-to-meandering clavate borings) suggest they were produced by members of the families Teredinidae, whereas that T. clavatus features (short clavate borings) were produced by extant members of the Family Pholadidae. Given that burrows of T. clavatus were oriented parallel to the wood fibers,) we suggest juvenile forms of teredinids as tracemakers. An extraordinary larger size (4 cm) wood boring attributed to Apetoichnus longissimus was produced by the rare and enigmatic species of Kuphus polythalamius giant teredinid. Absence of part of the wood, and parts of the borings suggest these were affected by the action of abrasion and erosive processes. Wood regions with higher infestation suggest log-grounds were available for the attack of bivalve larvae by a significant amount of time (long exposition) before burial, whereas wood-fragments with lower infestation density suggest shorter exposure time. Different size-categories in cross-sections in the studied log-grounds were related to successive colonization events by different ontogenetic stages of teredinid bivalves. Larger size borings could be related to first attack by teredinid larvae, and produced by young and adult teredinids, whereas smaller size borings could be related to a last attack by juveniles, before the wood burial. Furthermore, the accumulation of wood fragments (some with several meters in size) with A. longissimus and T. clavatus in the shallow marine deposits of La Meseta Formation can be the result of a transgressive event, and/or strong rains in these deposits, leaving them exposed to attack by teredinid larvae. This study explores the life histories of wood-boring bivalves and adds to the literature on ichnofossils in the Antarctic. [PROANTAR: 442676/2018-2].

993

Studying phytodetritus in a coastal marine system of the Western Antarctic Peninsula: organic matter content and fatty acids composition

Lic Florencia Bessega^1,2, Dr Gabriela L. Campana^1,3, Dr Fernando Momo^4,5, Dr Marleen De Troch⁶, Dr M. Liliana Quartino¹

¹Departamento de Biología Costera, Instituto Antártico Argentino, Buenos Aires, Argentina. ²Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. ³Depto de Ciencias Basicas, Universidad Nacional de Luján, Lujan, Argentina. ⁴Instituto de Ciencias, Universidad Nacional de General Sarmiento, Los polvorines, Argentina. ⁵INEDES- Universidad Nacional de Luján, LUJAN, Argentina. ⁶Biology Department, Marine Biology, Ghent University,, Ghent, Belgium

Abstract

Macroalgae are key primary producers in Antarctic coastal marine ecosystems. When dislodged from the seabed, they can be washed ashore or settle on the seafloor, where their fragments accumulate and degrade, becoming a crucial source of food and nutrients. Through these processes the carbon captured by marine ecosystems (blue carbon) is either assimilated by other organisms or forms organic detritus. Consequently, the resulting phytodetritus is expected to subsidize nearby trophic networks, particularly when there is low phytoplankton primary production. This study aims to identify the composition of phytodetritus in an Antarctic coastal system by analyzing the organic matter (OM) content and the identity and abundance of their constituent fatty acids (FA). Samples were collected using corers at six sites within Potter Cove (South Sheltand Islands), at 10 meters depth. Taxonomic identification was conducted for the >2 mm size fraction, while the < 2mm fraction was used to determine OM percentage and FA profiles. The >2mm phytodetritus fraction comprised Desmarestiales (Phaeophyceae), with a lesser presence of Rhodophyceae. OM content ranged from 2.00% (± 0.09) to 5.96% (± 0.24), with higher content at sites with greater deposition, likely influenced by the cyclonic circulation pattern in the cove. The relative abundance of saturated fatty acids (SAFA) and monounsaturated fatty acids (MUFA) exhibited site-dependent variations, whereas polyunsaturated fatty acids (PUFA) showed consistent levels among sites, albeit with higher dispersion values at sites with the postulated lower detrital deposition. These findings represent the first insights into the composition of phytodetritus in Potter Cove, a system characterized by generally low pelagic primary production, where phytodetritus probably plays a pivotal role in sustaining a high secondary production.

996

Antarctic phanerogamic communities: plant diversity and their dynamics with soil properties

Mariana Cassini da Cunha Lima¹, Flávia Ramos Ferrari², Alison Haynes², Jair Putzke³, Daniela Schimtz¹, Luiza Somelarte Sena¹, Fernandes Antonio Pereira¹, Ana Carolina Paula do Amaral¹, Márcio Rocha Francelino¹, Carlos Schaefer¹

¹Universidade Federal de Viçosa, Viçosa, Brazil. ²University of Wollongong, Wollongong, Australia. ³Universidade Federal do Pampa, São Gabriel, Brazil

Abstract

Research in the Antarctic continent is essential for understanding ecological interactions, soil-vegetation relationships and the landscape evolution in ice-free areas. The aim of this study was to analyze three areas of phanerogamic communities in the Demay Point region, King George Island and their connections with soil properties. The communities are situated in the coastal region and have three different distances from the glaciers. Vegetation communities were accessed through phytosociological method. Soil was collected at 0-20 cm depth to determine physical and chemical properties and organic matter. The results showed that area 1 had the highest species richness (13), while area 3 had the lowest (7), with the phanerogamic Deschampsia antarctica dominance in all areas. In area 1, it was associated with the ornithocoprophilous algae Prasiola crispa, along with mosses. In areas 2 and 3, D. antarctica was found in association with another phanerogamic species, Colobanthus quitensis. Soil analysis indicated that area 1 was more acidic (4.45) and with highest organic matter content (4.5 g/kg), while area 3 had the lowest (1.1 g/kg). Regarding nitrogen, area 1 had the highest value (0.41 dag/kg), contrasting with area 3, which had the lowest (0.05 dag/kg). In phosphorus, area 1 stood out with the highest index (703.86 mg/dm³), while area 2 had the lowest (105.9 mg/dm³). In aluminum analysis, area 1 presented the highest index (5.03 cmol/md³), while area 3 had the lowest (0,06 cmol/md³). The phanerogamic communities presented properties that affirm exchanges between their establishments and the animal influence. Associated with higher levels of aluminum, organic matter, and more acidic soils, they showed plant species correlated with fauna and well developed soils. Therefore, we can assert that species diversity is mediated by habitat and soil nutrients.

998

Satellite-derived variability of sea surface salinity and geostrophic currents off western Patagonia: Exploring the presence of a coastal freshening trend.

Dr. Gonzalo Saldías^1,2,3, MSc. Pedro Figueroa¹, MSc. David Carrasco¹, Dr. Diego Narváez^4,2, Dr. Iván Pérez-Santos^5,2, Dr. Carlos Lara⁶

¹Departamento de Física, Facultad de Ciencias, Universidad del Bío-Bio, Concepción, Chile. ²Centro de Investigación Oceanográfica COPAS COASTAL, Universidad de Concepción, Concepción, Chile. ³Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile. ⁴Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile. ⁵Centro i-mar, Universidad de los Lagos, Puerto Montt, Chile. ⁶Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Concepción, Chile

Abstract

The coastal ocean off western Patagonia is one of the main coastal regions with high freshwater inputs from rivers, rain, and glaciers in the southern hemisphere. This study provides an analysis of the seasonal and interannual variability of sea surface salinity, and meridional geostrophic transports (i.e. Cape Horn Current) in the coastal ocean off western Patagonia using improved satellite products of Sea Surface Salinity (SSS) and geostrophic velocities covering 11 years of data. Our results reveal a clear salinity minimum in a coastal band between 42-54°S associated with the highest freshwater content described in previous studies. The average geostrophic currents are stronger south of 49°S, in line with the location of the Cape Horn Current. The average salinity minimum tends to disappear south of 54°S, with salinity values increasing slightly southward. The seasonal cycle of salinity shows the most pronounced minimum in summer. The greatest variability in salinity (standard deviation of salinity fields) occurs in the southern region of the Cape Horn Current. Hovmöller plots reveal two cores of minimum salinities observed in spring and summer. The freshwater off the Gulf of Penas contributes to the northern core. The meridional geostrophic transport differs between the northern and southern sections, with transports predominantly towards the equator (pole) north (south) of about 47-48°S during spring-summer. There is a marked seasonal variability in the magnitude and northern limit of the southward-flowing Cape Horn Current, being extended further north during winter and with a maximum average magnitude during summer-fall. On interannual scale, a major drop in surface salinity occurred off northern and central Patagonia during 2018-2019. Finally, a potentially persistent freshening trend was identified for the coastal region off southern Patagonia (south of 52°S), nonetheless, longer time series are required to confirm a long-term freshening pattern.

999

Long-term trends in the upper layer stratification of the Indian Sector of the Southern Ocean during austral summer.

Ms Nirmala J Nair, Dr. Sabu P

National Centre for Polar and Ocean Research, Vasco-Da-Gama, India

Abstract

The upper ocean stratification plays a major role in reducing the vertical mixing and affects

several ocean biogeochemical processes. As a consequence of climate change, the average upper

layer stratification of the global ocean, including the Southern Ocean (SO), has increased. The

increase of stratification in the SO may have implications for the sinking of denser water masses,

which can affect the global thermohaline circulation. The present study attempts to understand

the recent stratification variability in the Indian Ocean sector of the Southern Ocean (ISSO)

during Austral summer using the model and re-analysis products. This study used the density

gradient between 1 m depth levels in the upper 300 m to represent the upper layer stratification.

The analysis shows that the upper layer stratification changes in the ISSO are different both

spatially and vertically. On the spatial scale, north of the Antarctic Circumpolar Current (ACC),

stratification is increasing, whereas it is decreasing towards the south. However, on the vertical

scale, the subsurface waters north of the ACC show a weaker stratification trend whereas south

of the ACC show a stronger stratification. The present study discussed the role of various

large-scale oceanic and atmospheric processes in the recent variability of upper layer

stratification of the ISSO.

1000

Solar Radiation Modeling in Antarctica Using WRF: Investigation and Comparison with Local Station Data

Jhon Contreras

Universidad de Concepción, Concepción, Chile

Abstract

Antarctica is a continent with an extremely cold climate, presenting complex challenges for scientific research, such as the study of solar radiation. Solar radiation plays a crucial role in the region's climatic processes, but its precise analysis is a challenge, due to the small number of measurements made in the area. On the other hand, solar radiation is an important source of renewable energy obtained with solar cells. In this context, modeling becomes an essential tool to study this climate variable and energy need in Antarctica. The Weather Research and Forecasting (WRF) model is the one chosen for this task, however, the validation of the results is a critical aspect to guarantee its accuracy and use in climate and environmental research. In this study, simulations of solar radiation will be carried out at different times of a year using the WRF model. To do this, GFS (Global Forecast System) data will be used. The modeled data will be compared with measurements from a solar monitoring station installed in the area (Syowa station), which will allow evaluating the performance of the model to represent solar radiation on this continent.

1005

Terra Nova Bay Polynya variability and its impact on thermohaline properties of the water column

Prof Giannetta Fusco¹, Dr Giuseppe Aulicino¹, Dr Vincenzo Capozzi¹, Dr Pasquale Castagno², Prof Yuri Cotroneo¹, Dr Massimiliano Esposito¹, Prof Giorgio Budillon¹

¹Università degli Studi di Napoli Parthenope, Napoli, Italy. ²Università di Messina, Messina, Italy

Abstract

The Terra Nova Bay (TNB) polynya is important in the modification of the thermohaline structure of the whole Ross Sea, resulting in the formation of High Salinity Shelf Water (HSSW), the densest water mass of the Southern Ocean. This study aims to investigate the processes that occur in the TNB polynya and the role of the air-sea interactions in the determination of its opening, activity and on the HSSW production that can ventilate the abyssal ocean circulation. First, we analyzed the role of the katabatic winds using meteorological data by the AWSs and ECMWF data, since 1994. In the second step the open water fractions from 2005 and 2021, detected by the Ice Surface Temperature (IST) imagery derived from the MODIS data, were used to estimate the opening and the activity of the polynya during the winter season. Then, we estimated the surface heat budget via empirical formulae in the investigated period. During the freezing season, heat flux from the ocean to the atmosphere can be assumed to result directly in ice production considering that ocean column is at its freezing point. Assuming that ice production rate depends on the net heat flux and on the polynya extension, it is possible to calculate the total production of salt released during sea ice formation and HSSW volume. Finally, a comparison between the estimated HSSW production and the salinity observed within the TNB water column is carried out.

1006

It's All Connected: Conjugate Studies of Polar Eclipses

Shane Coyle

Virginia Tech, Blacksburg, USA

Abstract

Geomagnetic activity in one hemisphere is communicated to the conjugate hemisphere via the magnetosphere. Ionospheric currents can be disrupted during an eclipse, which is particularly relevant to the polar auroral regions. As these current disruptions occur in one hemisphere, the other hemisphere reacts to the disruptions in ways that are not yet well understood. We present a study of the 2021 December Total Solar Eclipse that happened predominately in Antarctica from a set of ground based instrument stations on the Eastern Plateau. This latitudinal array of stations is magnetically conjugate to a similar chain of stations on the west coast of Greenland. We show coincident geomagnetic wave activity in both hemisphere contemporaneous to the eclipse progression across the arrays. We also discuss potential observations during the upcoming 2026 Eclipse that will traverse along the east coast of Greenland.

1008

Emperor Penguins on the Ice Shelf: Refugia for threats from Climate Change?

Marie-Charlott Rümmler, Stefan Knetsch, Christian Pfeifer, Osama Mustafa

ThINK, Jena, Germany

Abstract

Emperor Penguin are, like many species, threatened by climate change. Recent studies have shown that 80 % of Emperor Penguin colonies are threatened by extinction under a business-as-usual greenhouse gas emission scenario. Most of Emperor penguin colonies are dependent on fast ice as breeding habitat. The at least in some regions of Antarctica decreasing fast ice, earlier break-ups, or increased instability put breeding success and colony persistence at risk. One possibility to resolving this risk is the transposition of the colony to the ice shelf, which has been observed in some colonies already, like Atka Iceport or Astrid Ice Tongue. In those colonies, the ice shelf may serve as a climate change refugium, possibly reducing the predicted colony losses.

In the presented study, we examined how many of the Emperor Penguin colonies already use the ice shelf as breeding habitat, to what proportion of the colony, and how they did in history. We used Sentinel and Landsat satellite imagery to manually inspect known locations of Emperor Penguin breeding sites for guano stains on the ice shelf. If detected, the area of guano patches has been measured to get an estimate of the magnitude of individuals on the ice shelf. To gain insight into seasonal dynamics, several images per season have been analysed. The historical context was also considered by acquiring images of several past seasons.

1009

Exploring pathogenic traits of Antarctic soil bacteria through culturomics and virulence agars using Dictyostelium discoideum

Ian Pérez¹, Antonia Ramos¹, Gabriela Carrasco², Matías Gálvez², Nicolas Canales², Jacquelinne Acuña³, Verónica Cambiazo⁴, Milko Jorquera³, Andrés E. Marcoleta², Francisco P. Chávez¹

¹University of Chile, Systems Microbiology Laboratory (SysmicroLab), Department of Biology, Faculty of Sciences., Santiago de Chile, Chile. ²University of Chile, Integrative Microbiology Group, Department of Biology, Faculty of Sciences., Santiago de Chile, Chile. ³University of La Frontera, Laboratory of Applied Microbial Ecology (EMALAB), Scientific and Technological Center of Bioresources (BIOREN)., Temuco, Chile. ⁴University of Chile, Laboratory of Bioinformatics and Gene Expression, National Institute of Food Technology, INTA., Santiago de Chile, Chile

Abstract

Once considered sterile, the Antarctic continent reveals diverse microbial communities due to climate change-induced ice retreat. Recent research highlights broad taxonomic and physiological diversity among Antarctic soil microorganisms, identifying bacterial factors related to virulence, antibiotic resistance, and other phenotypic aspects. These findings underscore the importance of vigilant monitoring due to the potential transmission of these elements between humans and animals. Dictyostelium discoideum, a social amoeba, is an ideal model for studying bacterial virulence mechanisms, possessing human orthologous genes and a phagocytic mechanism like human macrophages. Amoeba-bacteria interactions involve symbiotic relationships, with amoebae preying on bacteria while bacteria resist predation and may affect amoebae' social development, creating selective pressure for the evolution of pathogenic bacteria. This study aims to elucidate the functional virulence mechanisms of Antarctic soil bacteria and their interactions with D. discoideum. We conducted phagocytosis and social development assays on Antarctic bacteria to assess their pathogenic potential. Our findings revealed that numerous bacterial isolates from Antarctic soil displayed virulence factors, as demonstrated by the D. discoideum assays and virulence agar tests. An in-depth analysis of these virulence factors will enhance our comprehension of how microorganisms adapt to extreme conditions and could unveil novel virulence mechanisms. Ultimately, our research offers an extensive methodology for identifying and analyzing virulence factors in bacteria from environments with extreme conditions through culturomics and functional assays.

1010

Impact of the absence of red blood cells, hemoglobin, and myoglobin on tissue-specific carbon monoxide (CO) concentrations in Antarctic Icefish

Tyler Lewis¹, Christian Bolton², Dr. Kristin O'Brien², Dr. Michael Tift¹

¹UNC Wilmington, Wilmington, USA. ²University of Alaska Fairbanks, Fairbanks, USA

Abstract

Antarctic icefish, Family Channichthyidae, inhabit the Southern Ocean surrounding Antarctica, the most thermally stable environment on Earth. These cold, stable temperatures allow dissolved oxygen to be highly concentrated resulting in unique adaptations in a certain species of icefish (C. aceratus), lacking hemoglobin and myoglobin, resulting in translucent blood and white skeletal muscle. Hemoglobin and myoglobin are sources of heme that are naturally turned over by heme oxygenase enzymes, resulting in the endogenous production of carbon monoxide (CO).

The concentrations of CO were compared in several tissues from a species that lacks red blood cells, hemoglobin, and myoglobin (Chaenocephalus aceratus), and a closely related species that has red blood cells, hemoglobin, and myoglobin (Notothenia coriiceps). Heart, skeletal muscle, gill, stomach, liver, kidney, and spleen tissues were collected from 7 individuals of C. aceratus and 8 individuals of N. coriiceps. The CO concentration in the spleen, skeletal muscle, and gill of C. aceratus were 13.2, 1.4, and 3.2 times lower, respectively, when compared to N. coriiceps. This is likely due to the role of the spleen in erythrocyte and hemoglobin degradation, and the presence of myoglobin in skeletal muscle and the gill of N. coriiceps. Surprisingly, the CO concentration in the heart of C. aceratus was significantly higher than N. coriiceps by an average of 0.8 pmol/mg. Higher mitochondrial concentrations in the heart of C. aceratus could provide alternative heme sources (e.g., cytochromes) for CO production, or a sink for CO. There was no significant difference in CO concentration between both species in the kidney, liver, or stomach.

Future studies investigating the presence and activity of heme oxygenase enzymes in tissues and the role of CO on mitochondrial function and oxygen delivery would provide valuable information about the evolutionary role of CO in fish.

1016

Krill Conservation: Integrating Ecophysiology and Microbiome Research for Global Awareness and Collaboration

Mr. Alejandro Font¹, Mr. So Kawaguchi², Mr. Rob King², Mr. César A. Cárdenas^1,3, Ms. Lorena Rebolledo¹, Mr. Sebastián Menéndez¹, Mr. Daniel Ramírez¹, Mr. Kurt Paschke^3,4,5, Mr. Luis Vargas-Charcoff^3,4,6, Mr. David Medina-Ortiz^7,8, Mr. Roberto Uribe-Paredes⁷, Mr. Ellie Poulin^3,9, Ms. Leyla Cárdenas^4,10, Mr. Rodolfo Rondon¹

¹Departamento Científico, Instituto Antártico Chileno, Punta Arenas, Chile. ²Antarctic Australian Division, Hobart, Australia. ³Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago de Chile, Chile. ⁴Centro de Investigacion en dinamica de ecosistemas marinos de altas latitudes (IDEAL), Valdivia, Chile. ⁵Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile. ⁶Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile. ⁷Departamento de Ingeniería en Computación, Universidad de Magallanes, Punta Arenas, Chile. ⁸Centre for Biotechnology and Bioengineering, CeBiB, Universidad de Chile, Santiago de Chile, Chile. ⁹Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago de Chile, Chile. ¹⁰Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile

Abstract

Antarctic Krill (Euphausia superba) is one of the principal components in the diets of top predators, playing a crucial role in the food webs of the Southern Ocean. By converting the energy derived from primary producers into biomass accessible to various top predators, Antarctic Krill not only supports the ecosystem's biodiversity but also plays an essential role in carbon sequestration. As the most significant biomass in Southern Ocean fisheries, krill harvesting is strictly regulated by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). On the other hand, climate change poses a formidable threat, with potential shifts in temperature, sea ice extent, and ocean pH levels threatening to disrupt krill populations, their habitat, and distribution. Such changes could profoundly impact Antarctic ecosystems and the sustainability of krill fisheries. For these reasons, it is key to raise awareness and link citizens of Chile and the world about the importance of krill with permanent exhibitions in gateway cities to Antarctica, such as the International Antarctic Center (IAC) that will be located in the city of Punta Arenas. To further our understanding of krill's ecological dynamics and adaptability, our study focuses on analysing the gut microbiomes of krill across various locations on the Antarctic Peninsula. This study, coupled with molecular ecophysiological assessments, aims to gauge the impact of global change on krill. These molecular studies will lead to performing bioinformatic procedures on prokaryotic 16S sequence data and total transcripts from control krill and stress responses with the RNAseq technique. By enhancing our investigation through international collaboration, we strive to expand the research network dedicated to captive krill studies, which is essential for anticipating and mitigating the repercussions of environmental change.

1020

The seas of Antarctica, beyond Antarctica

Dr. Estelvina Rodríguez Portillo, MSc. Tatiana Wieczorko, Gabiota Mendoza, Victor Vera

National University of Itapua, Encarnación, Paraguay

Abstract

Not only is Antarctica home to 90% of the planet's ice and 77% of available fresh water; Its seas are key to the influence of climate at a global level. Therefore, this work raises the importance and need for evaluation in different areas, beyond the limits of the Southern Ocean, since some of these extreme events can interact, causing cascading impacts. This complex interaction of the Antarctic climate in confluence with convections of tropical climates. Studies indicate that strong winds, low temperatures and the dynamics of Antarctic sea ice lead to current patterns that influence global ocean currents (Rodrigo C, 2008). The background also indicates an acceleration of the Antarctic Circumpolar Current (ACC) facilitating the exchange of properties such as heat or carbon between ocean basins (Rui Shi et al, 2021), therefore these properties are expected to increase in tropical regions. The objective of this work was to carry out an analytical review of the influence of the Antarctic ocean current in tropical countries such as Paraguay. The ACC can affect Paraguay's climate by modulating ocean temperature and influencing regional atmospheric circulation. Changes in these conditions can have significant impacts on weather patterns, such as temperature, humidity, and precipitation patterns. Understanding the interconnection of these processes will help improve climate decision-making policies

1026

Game for teaching Artificial Intelligence and responses to crises and emergencies in Antarctica

Studant/ ECR Natasha Barros-Delben¹, Dr./ECR Paola Barros-Delben^1,2,3,4, Dr. / ECR Priscilla Barros-Delben^2,1

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²Polar Sapiens, Florianópolis, Brazil. ³APECS-Brazil, Belo Horizonte, Brazil. ⁴South of Brazil University, Palhoça, Brazil

Abstract

The teaching of Artificial Intelligence (AI) and topics related to Antarctica, although the need for technological and environmental education is latent, is still incipient in Brazil. This work aimed to develop a board game for teaching AI to optimize responses to crises and emergencies in Antarctica, also contributing to the targeting of resources during real undesirable situations. The results found are the solution of including an evolutionary genetic algorithm to identify the most efficient response in decision-making that meets the criteria for prioritizing (a) human lives, lower indicators of loss and damage (b) environmental, (c) organizational and institutional, with the lowest cost (d) financial and (e) time for response. The algorithm ranges from recognition of the emergency, immediate and urgent needs for tile support, rescue, containment, and evacuation, available self-management resources, from the country involved in the crisis and countries linked to international agreements, in addition to prior training for prevention and nutrition of the database for prediction. The potential of the proposed game, in analog (paper) and digital versions, aiming for greater reach and inclusion, is significant for teaching logic and programming, related to important issues in the 21st century such as climate change, the impact of melting glaciers, the exponential growth of tourism in polar regions, consequently the human impact on the locations and Brazil's strategic geopolitical interest below the 60th parallel.

1027

Mapping the topography of a continental oasis in Dronning Maud Land by use of UAV and satellite remote sensing

Osama Mustafa¹, Dale T. Andersen², Daniel Butvidas³, Marie-Charlott Rümmler¹, Fanny Seidel¹, Christian Pfeifer¹

¹ThINK, Jena, Germany. ²Carl Sagan Center, SETI Institute, Mountain View, USA. ³Trimble Inc., Westminster, USA

Abstract

Accurate topographic maps are a precondition for an effective management and monitoring of protected areas. In addition, they are an important base for many kinds of fieldwork and research. This also applies for Antarctic areas. Classic methods of land surveying are precise, but time consuming. The use of UAVs now provides the opportunity to gather high resolution topographic information even in locations without a nearby operating station or with difficult access.

During an expedition to Otto-von-Gruber-Gebirge, a high mountain inland oasis in Dronning Maud Land, which is proposed to be designated as an Antarctic Specially Protected Area (ASPA) we used two types of UAVs to acquire detailed imagery of the surface of the area. For the UAV section, Trimble Business Center and Trimble RTK Post Processing Service was utilized to calculate the UAV base station position (+/- 2 cm), which produced high-precision datasets (orthomosaic and digital surface model) using PPK (post-processed kinematics). The UAV data do not cover the entire area of interest. Therefore, the remaining parts satellite imagery of Worldview-2 and Sentinel-2 were used in combination with the Reference Elevation Model of Antarctica (REMA), which is also derived from high-resolution Satellite imagery.

From the resulting composite dataset, information on the character of the relief and the distribution of topographic features were derived.

We present the final product of a topographic map and discuss questions on the combination of datasets with different precision scale, temporal and spatial feature differentiation and the application of conventions for place names.

1028

Perception of Antarctic expeditioners on biosafety and conduct in the polar environment for collecting and sampling samples

Dr/ECR Priscilla Barros-Delben^1,2, Student Natasha Barros-Delben¹, Dr. Roberto Moraes Cruz¹, Dr/ECR Paola Barros-Delben^1,2,3

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²Polar Sapiens, Florianópolis, Brazil. ³Association of Polar Researchers - Brazil, Belo Horizonte, Brazil

Abstract

Human activities in polar environments combined with contemporary climate change increase biological risks for both fauna and flora and people. The objective of this study was to analyze the perception of polar expeditioners regarding the concept of biosafety and behaviors prescribed and practiced in the polar environment for collecting and handling samples. Method: Online questionnaire to access the perception of field experts who collect and/or handle polar samples. Results: The survey respondents (n=8) are characterized by significant experience in polar expeditions, the majority (60%) of field researchers, project coordinators, and teachers (40%), work in the field (60%) with manipulation of biological samples (67%) and carried out activities at Latin American (88.8%) or European (11.1%) stations. Everyone responded that they know what biosafety and biological risk are, but 55.6% did not undergo biosafety training; 55.5% do not have or do not know if there is an isolated or exclusive place to handle or store polar samples; and 33.3% do not register or do not know whether to register basic identification information for the polar samples obtained. Also, they do not know the psychosocial risks related to their polar research (55.6%) and do not have or do not know if there are risk management measures established and easily accessible for consultation (55.5%). Conclusion: Partial results suggest that there are gaps in biosafety and safe behavior in polar research contexts. It is planned to develop a standardized biosafety protocol and behavioral training to increase awareness about sustainability and contribute to practical actions to reduce the impact of human activities in polar regions and the dispersion of biological risks to the planet.

1030

Presenting the Antarctic Environments Portal: scientific research in support of Antarctic policymaking

Dr Keith Reid¹, Dr Chandrika Nath²

¹University of Tasmania, Hobart, Australia. ²SCAR, Cambridge, United Kingdom

Abstract

The Antarctic Environments Portal (the Portal) provides a web-based source of independent and up-to-date scientific information to support the work of decision makers in the Antarctic Treaty System (ATS). The Portal delivers reliable, policy-ready summaries on priority issues for Antarctic conservation and management. It also raises awareness of emerging scientific issues to support informed discussions and prioritisation of issues. Articles published on the Portal are all subject to peer-review and are grouped into thematic topics including marine, terrestrial, human activities, inland aquatic environments, atmosphere and cryosphere.

SCAR’s primary aim in hosting the Portal is to support engagement in the ATS on science and conservation issues affecting the management of Antarctica and the Southern Ocean. The CEP/ATCM has recognised the value of the Portal in providing a source of impartial information on topics of importance to the ATS.

Though the Portal is primarily aimed at Antarctic Treaty stakeholders, the content is freely accessible and intended to be understandable by a general audience. In line with SCAR’s objectives on outreach, SCAR intends to more actively promote the Portal to wider audiences.

The main output of the Portal to date has been its 35 Information Summaries, however the secretariat also generates infographics to visually complement the detailed Information Summaries. SCAR has played a key role in redesigning the website to be more user friendly and widely accessible.

A key challenge is ensuring that the Portal generates sufficient timely and relevant content to attract regular users from the target audience and beyond. Currently, the pool of authors volunteering to produce Information Summaries is small, due to limited awareness of the Portal amongst the SCAR community. By showcasing the Portal at the OSC, we hope to highlight the opportunities the Portal presents SCAR scientists to communicate their work to a policy audience.

1031

Progress of high pressure hot water energy-saving supply system of DeepRAD project

Prof. Heng Zuo, Mr. Jing Xu, Mr. Xiaokang Ni, Mr. Guohua Zhou, Ms. Qun Ge

Nanjing institute of astronomical optics and technology, Nanjing, China

Abstract

Regarding the newly discovered large deeply buried subglacial lake in Princess Elizabeth Land, Antarctica, our project has established a set of deep rapid access drilling(DeepRAD) technologies and equipment for the large depths of ice sheets. In order to achieve rapid and pollution-free drilling of 3,600 meters, a high-pressure hot water energy-saving supply system has been developed, which can continuously provide hot water with a maximum temperature of 90°C, a flow rate of 210L/min, and a maximum output pressure of 10MPa. This system includes a snowmelt water storage and circulation system, a rapid heating system, and a drilling water pressurization system. The rapid heating system uses a fuel oil boiler as the main heating equipment, propylene glycol antifreeze as the heating medium, and the plate heat exchangers are used to isolate the heating water cycle from the drilling water cycle, reducing the possibility of drilling water pollution, in addition it also allows the fuel oil boiler to be started and stopped at any time under different heating power conditions in the Antarctic environment. The pressurization system adopts the parallel connection of four CAT pumps to achieve a maximum water supply rate of 378L/min. Both the heating system and the pressurization system adopt modular designs. Each system comprises four units, and the failure of any single unit will not affect the normal operation of the entire system.

1032

Social and Geographical Impact of Seasonal Variations on an Antarctic Station’s Life

PhD student Rachel Prat¹, Emmanuelle Sultan²

¹Ecole doctorale Espaces, Temps, Cultures (Université Paris Nanterre), Nanterre, France. ²Musée National d'Histoire Naturelle, Paris, France

Abstract

Antarctica has only two seasons: winter and summer. It is possible to make the difference between these two seasons by the luminosity. Indeed all places located under a polar circle can be defined by at least 24 hours without sun during winter and 24 hours without night during summer. This variation leads to many effects on the climate, the environment as so human life. As Mauss (with Beuchat, 1904-1905) describes it for the Inuits, arctic seasonal variation causes a seasonal modification of the social morphology. Subsequent to an ethnography (still undergoing, conducted in the context of the Habit-ANT? project lead by Emmanuelle Sultan) of the Dumont d’Urville’s French Station (Adelie Land) started in 2021, I show that “bi-seasonality” is an important concept to understand life on Antarctic stations.

1033

Baleen whale abundance estimates for CCAMLR 48.1, and spatiotemporal overlap with krill fishing.

Mr. Angus Henderson¹, Dr. Nat Kelly², Prof. Mary-Anne Lea¹, Prof. Mark Hindell³, Dr. Andrew Lowther⁴

¹University of Tasmania, Hobart, Australia. ²Australian Antarctic Division, Hobart, Australia. ³Unversity of Tasmania, Hobart, Australia. ⁴Norwegian Polar Institute, Tromso, Norway

Abstract

Many Southern Ocean foraging baleen whales populations have recovered substantially in recent decades, and are becoming a dominant Southern Ocean Antarctic Krill consumer. Antarctic krill are a keystone species in Southern Ocean food webs, a critical linkage in the transfer of energy from primary producers to higher tropic levels. With the increasing interest in ensuring krill fishing is sustainable, we sought to estimate the abundance of baleen whales in areas over which the fishery is managed along the west Antarctic Peninsula.

We use data collected by tourist vessel-based observers to develop model-based spatiotemporal abundance estimates for baleen whales. Abundance estimates were made for CCAMLR management region Subarea 48.1 across three 45-days time periods between November and March with a combined estimate for baleen whale abundance of 67,000 in January/February (for fin, humpback, and minke whales combined, 28, 34 & 5 thousand individuals respectively). Fin whale abundance remained constant (~28,000 individuals) between November and March, while for humpback whale abundance peaked in March (~35,000 individuals) and Antarctic minke whale abundance peaked in January/February (~5,000 individuals). The broad scale overlap between krill fishing and baleen whales occurred across November-March, mostly in the Gerlache Strait, Bransfield Strait, and South Shetland Islands West strata, while for the Joinville and Powel Basin strata, overlap was recorded in March only.

We evidence further recovery of fin and humpback populations on summer foraging grounds, and a likely decline in minke whales in the region. We show broad scale overlap with the krill fishery varies during the summer foraging season, as baleen whale abundance and krill catch are not constant. Humpback whale abundance peaks in March, likely remaining high into April and May, and will continue to spatiotemporally overlap with increasing krill catch, which peaks in April and May in the region.

1037

Matrix of Psychosocial Risks in Antarctica

Dr/ ECR Paola Barros-Delben^1,2,3,4, Dr Rafaela Luiza Trevisan¹, Dr Davi Baasch¹, Dr. Diogo Picchioni⁵, MCS/ ECR Ana Carolina Pont³, Prof. Roberto Moraes Cruz¹

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²South of Brazil University, Palhoça, Brazil. ³APECS-Brazil, Belo Horizonte, Brazil. ⁴Polar Sapiens, Florianópolis, Brazil. ⁵Civil police, Florianópolis, Brazil

Abstract

Activities in Antarctica highlight the human factor in risk prevention as strategic. This study aimed to develop a matrix to guide the dynamic mapping of psychosocial risks in Antarctica. Method: Retrospective analysis of 7 experiences in Antarctica and bibliographic review of the last 10 years in the area. Results: The psychosocial risk matrix was constructed considering categories for activities in Antarctica: 1. idiosyncratic aspects, personal history and psychological and psychosocial repertoire; 2) individual skills combined for self-sufficiency, training and qualification for activity; 3) basic, operational and superior needs of workers; 4) workers’ expectations and growth possibilities; 5) organizational and national culture; 6) values and purposes aligned between institution and individual; 7) occupational health and safety policies; 8) autonomy; 9) aspects of the working day, intensity, workload and working conditions and the 24-hour readiness factor; 10) leadership; 11) support and social relationships at work and externally; 12) notion of belonging and social and occupational role; 13) extra-work factors; 14) Institutional communication and feedback; 15) Job/contract security; 16) Typical psychological demands at work; 17) Psychological, behavioral, cognitive and emotional responses to interaction with the context; 18) Equality, equity and diversity at work; 19) Valuing workers and rewarding them for their performance; 20) Ergonomics at work, comfort and other compensations for activities. Different from daily organizational contexts, human activities in Antarctica require mechanisms to predict the incidence of undesirable events that can be self-managed by those involved, or that demand the map of psychosocial indicators in a dynamic way to minimize risks and associated risks. The matrix presents itself as a promising strategic tool in the management of expeditions, both in the selection and monitoring of personnel.

1038

Analysis of Antarctic Research Trends and Status Among Global Polar Research Institutions: Focusing on Climate Change-Related Studies

YOUNA HWANG¹, Chul Lee²

¹Korea Polar Research Institute, Incheon, Korea, Republic of. ²Korea Institute of Science and Technology Information, Secoul, Korea, Republic of

Abstract

The purpose of this study is to examine trends in Antarctic globally conducted by polar research institutions, with a particular emphasis on the direction of research related to climate change in Antarctica. To achieve this, data from representative polar research institutions across nine countries was compiled using the Web of Science (WoS), from which climate change-related information was extracted. Following this, a bibliometric analysis was conducted to analyze research trends (by year and institution), knowledge flow between research fields, and research similarity among institutions.

Through the analysis of knowledge inflow and outflow, this study identified leading and trailing technologies in climate change-related research, providing significant insights into the future directions of Antarctic climate change research. Furthermore, by utilizing deep learning-based embedding models, the similarity of research among domestic and international polar research institutions was analyzed, aiming to understand the research patterns of each institution. Specifically, we constructed a citation matrix from approximately 90 million articles using the citation information provided by the Web of Science. This matrix was then restructured into a technology topic cluster matrix to derive knowledge flow-in and flow-out relationships between technologies, and to analyze leading and trailing technologies related to polar research. Furthermore, the titles, abstracts, and author keywords of all articles in the Web of Science were transformed into embedding vectors through a deep learning-based Sentence Transformer model, enabling the quantitative measurement of research similarity between polar research institutions.

This study plays a crucial role in understanding the overarching trends in climate change research conducted by polar research institutions worldwide. Moreover, the application of big data and AI models offers a macroscopic view of the flow of polar research, which will assist in data-driven planning for polar research.

1039

Application of the reflectance spectroscopy technique in the study of phosphatic soils influenced by penguins

Geography undergraduate student Isabelle de Angeli Oliveira, Geography undergraduate student Amanda Melissa Pessoa Lopes, PhD in soil science Rafael Gomes Siqueira, PhD student in soil science Clara Glória Oliveira Baldi, PhD student in soil science Cássio Marques Moquedace, Full professor in the Departament of Soils Márcio Rocha Francelino, Full professor in the Departament of Soils Elpídio Inácio Fernandes Filho, Full Professor Carlos Ernesto Gonçalves Reynaud Schaefer

Federal University of Viçosa, Viçosa, Brazil

Abstract

Reflectance spectroscopy (RE) can help to produce information on Antarctic soils under phosphatization, a process that causes mineralogical and geochemical changes in soils. We conducted a characterization of the spectral behavior of soils influenced by phosphatization in Lions Rump, King George Island. We used the ASD FieldSpec 4 Hi-Res spectroradiometer to read 6 samples of two Cambisols (“Ornithic”) with phosphatic horizons (A, Bi and BC). The sensor quantifies the reflectance in the wavelengths of visible (400 ~ 700nm) and near infrared (NIR) - 750 ~ 2500nm. The highest reflectance was related to the Bi horizons, and the lowest values were related to the A horizons, whereas the BC horizons showed intermediate values. In the visible range, all horizons presented increasing values from the blue to red bands, although in different levels. We observed values around 850nm in most horizons in the NIR region close to the Red Edge (Vis-NIR transition), with Bi horizons presenting reflectance between 30-40%, BC of 25% and A of 20%. The reflectance tends to fall discontinuously in the short-wave infrared (SWIR) region, with pronounced depressions associated with clay and hygroscopic water in Bi horizons. There was a close relationship between the reflectance and the pedogenetic degree of the Bi horizons, which is linked to the higher presence of white minerals of phosphate (e.g., leucophosphite), that confer a whitish coloration to the most developed phosphatic horizons. This was not reflected in the less developed BC horizons. Finally, the lowest reflectance of the A horizons is related to the darker color of these superficial soil layers in direct contact with black carbon substances derived from the penguin guano decomposition. Our results showed that ER has great potential to help interpret quantitative spectral data in studies of the pedogenesis of soils influenced by penguins.

1040

Checklists for health and safety in Antarctica: psychology, medicine and biology

Msc Daniela Silvestre¹, Dra. Priscilla Barros Delben¹, Msc Lorrane Olivet Araújo², Dr. Thiago Teixeira Mendes³, Msc Luciano Emanuel Gonzalez⁴, Dr. Roberto Moraes Crusz¹, Dra. Paola Barros Delben¹

¹Federal University of Santa Catarina UFSC, Florianópolis, Brazil. ²Federal University of Minas Gerais, Belo Horizonte, Brazil. ³Federal University of Bahia, Salvador, Brazil. ⁴Universidad de Buenos Aires, Buenos Aires, Argentina

Abstract

Isolated, Confined, and Extreme Environments, called ICE, such as Antarctica and space analogs, require greater autonomy for everyone involved in human activities, due to difficult access in emergencies or crises. The greater the instrumentation, the lower the risk of critical incidents and simple measures such as a checklist can be useful when pre-expedition minimum attention requirements. The objective of the work was to bring together the main elements to be met to promote the health and safety of expeditioners in Antarctica and to prevent accidents, illnesses, and crises by constructing an interdisciplinary checklist. Method: literature review, documentary, historical consultation, and access to the database of academic and professional experiences of activities in Antarctica over the last 10 years. Results: the instrument developed guides pre-expedition processes, considering the analysis of environmental, organizational, international relations, contamination, social, and individual factors in the field of psychology, medicine, and biology, providing training and qualifications, examinations, and fundamental tests and, in addition, compliance with bureaucratic criteria and guidelines for planning aimed at better performance. A checklist is a tool that can be analog on paper or digital and supports a program for managing health and safety risk indicators with economic impacts evidenced in comparison to reactive actions, an example of the need for evacuations. The prospect is that it will also be implemented in spatial analog contexts, with the addition of specific analysis factors such as radiation and gravity.

1041

The Antarctic ascidian Cnemidocarpa verrucosa and the ecological significance as a substrate for epibiotic communities in a context of environmental changes

Dr Clara Rimondino^1,2,3, Dr Gastón Alurralde^4,5, Dr Emilia Calcagno^1,2, Dr Tamara Maggioni^1,2,3, Dr Carla de Aranzamendi^1,2, Dr Camila Neder^1,2, Dr Marcos Tatián^1,2

Abstract

In coastal marine environments, the availability of free substrate significantly influences the distribution and abundance of sessile benthic organisms. The presence of organisms acting as biological substrates can facilitate the establishment of other benthic organisms, in a phenomenon known as epibiosis. The epibiosis intensity (i.e. the richness and abundance of epibionts) varies across latitudinal and depth gradients, and basibiont characteristics. Recent increases in sedimentation from melting coastal glaciers threaten local biodiversity in the West Antarctic Peninsula. Ascidians stand despite changing environmental conditions, providing a stable surface for a variety of epibionts to attach and grow. Thereby, ascidians are expected to enrich biodiversity and create habitat heterogeneity. We analysed macroepibiotic assemblages occurring on the abundant ascidian Cnemidocarpa verrucosa from two areas within Potter Cove (South Shetland Islands, Antarctica): one characterized by soft substrate and high sediments level (“brown water”) and, the other one, characterized by hard substrate and low sediments level (“blue water”). The hypothesis was that epibiosis intensity varies according to environmental conditions such as substrate type and sedimentation level, as well as, individual characteristics of the occupied body area on the basibiont. We observed diverse epibionts, including algae, sponges, bryozoans, and even other ascidians. In addition, a higher epibiosis intensity was found on ascidians living on soft substrate and brown water with further effects associated to properties and characteristics of the body zones parts within the same basibiont. In a context of increasing temperature and consequent higher sediment discharge in coastal marine zones, the composition of benthic communities is expected to be further affected. In this regard, ascidians emerge as key organisms in the structure of these shallow Antarctic communities.

1043

Physiological effects on Antarctic fish Harpagifer antarcticus inhabiting nearby human settlements and scientific research bases in King George Island, Antarctica

Karen Fabres¹, Gustavo Chiang², Paulina Bahamonde^1,3,4

¹Center for Resilience, Adaptation and Mitigation, Faculty of Sciences, Universidad Mayor, Temuco, Chile. ²Sustainability Research Centre & Department Ecology and Biodiversity, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile. ³Millennium Nucleus of Austral Invasive Salmonids (INVASAL), Concepción, Chile. ⁴Cape Horn International Center (CHIC), Universidad de Magallanes, Puerto Williams, Chile

Abstract

Antarctic has been urbanized over the years, with scientific and military stations located mainly in coastal areas. The human presence activities that may have detrimental consequences for the local biota. Wastewater effluents are currently one of the most worrying sources of contaminants into aquatic ecosystems, given that the abundance and diversity of pharmaceuticals and personal care products (PPCPs). PPCPs are considered emerging pollutants that can negatively affect wildlife at very low concentrations in the environment. However, there is scarce information available on the presence and effects of PPCPs in polar areas. Based on this background, we assessed the possible effect of wastewater effluents on local, small bodies, low mobile fish species near research and military bases in Fildes Bay, King George Island (South Shetland Islands). In December 2023, a total of 186 Harpagifer antarticus were collected from five different sites: three sites near by scientific bases and two reference sites. The fish were kept in aquariums overnight to compensate for the stress produced by sampling. Total length, total weight, gonad, and liver weight were measured. It is observed a 1,2 sex ratio female per male; and that there are significant differences between the condition, gonadosomatic (GSI) and liversomatic index (LSI) of fish between sites. In overall, fish belonging to Nelson Glacier (reference site) and Artigas Research Station (a scientific research station but with no sewage effluent discharge) showed higher condition, GSI and LSI. On the other hand, fish from Collins Glacier (reference site) and from Great Wall research station (with effluent discharge) were smaller, lower LSI and GSI. Fish from Escudero Base had no clear tendency. Gene expression analysis will be performed to study effects of endocrine disruption in gonads of H. antarticus. The study described reflects research in progress. This project was funded by FONDECYT 1230485.

1044

Origin and acquisition of rhizosphere microbes from antarctic vascular plants revealed by molecular markers and metagenomics

Dr. Eduardo Castro-Nallar¹, Dr. Sergio Guajardo-Leiva¹, Mr. Valentín Berríos-Farías¹, Dr. Amy Zanne²

¹Universidad de Talca, Talca, Chile. ²Cary Institute of Ecosystem Studies, Millbrook, NY, USA

Abstract

Rhizosphere microbial communities exert critical roles in plant health, nutrient cycling, and the fertility of the soil. Despite this, the origin and acquisition of rhizosphere microbes is not fully understood. In this study, we investigated the diversity and potential origin of the microbial communities on Colobanthus quitensis (Cq) and Deschampsia antarctica(Da). Microbial communities form the rhizoshere of Da exhibited decreased richness and diversity in comparison with Cq and Da.Cq. In contrast, fungal diversity was strongly associated with plant species, where the rhizospehre of Da exhibited greater diversity than that of Cq. We also found that species turnover is mostly determined by environmental and geographic filters, and to a lesser extent, to biotic filters. Morover, our analyses showed that the likely origin of rhizosphere bacteria is local soils that contribute to homogenize rhizosphere community composition among different plant species growing on the same sites. The observed pattern is different for fungi, where the rhizosphere of Cq exhibits a strong species specific component, unlike Da. Finally, we also obtained a genome catalog of 1481 bacterial and 3 archaeal genomes, all of which where categorized as medium (≥50% completeness; <10% contamination) and high quality ((≥90% completeness; <5% contamination). We also show a catalog of microbial genes, functions, and traits associated with plants’ rhizosphere and soil without vegetation cover.

1046

Predictin the AE Index Using Deep Learning Techniques and Solar Wind Data

Yerko Jelcic¹, Bea Zenteno-Quinteros^1,2, Victor A. Pinto^1,2

¹Departamento de Física, Universidad de Santiago de Chile, Santiago, Chile. ²Center for Interdisciplinary Research in Astrophysics and Space Sciences (CIRAS), USACH, Santiago, Chile

Abstract

Intense geomagnetic activity resulting from the interaction between solar wind plasma and the Earth's magnetosphere poses significant threats to both terrestrial and space-based electrical and computational infrastructures. Among its many effects, geomagnetic disturbances can enhance ionospheric currents, particularly in the auroral regions. This intensification is quantified through several indices, such as the Auroral Electrojet index which measures the westward component of the magnetic field perturbations that propagate to the ground. The AE index is an important indicator of the intensity of auroral activity, which correlates with various phenomena within the Earth's magnetosphere. Thus, the prediction of the AE index is key to space weather modeling and monitoring. In this study, we used solar wind data from 1995 to 2020 from the OMNI database to develop a deep-learning empirical model for predicting the geomagnetic AE index. We employed the PyTorch framework to train different neural networks, in order to produce an AE prediction 30 minutes into the future. Here we discuss the results obtained from using various neural network architectures, including a Multilayer Perceptron, (ANN), a Long Short-Term Memory (LSTM) network, and a Convolutional Neural Network. We also discuss the issues that arise with the training and with the use of a curated database as opposed to real-time data. We present a series of metrics to evaluate the performance of these models and compare them, to understand what modifications may improve the results. The results obtained show that the deep learning approach is promising and that the construction of a prediction model in real time for the AE index is possible.

1048

Is there a link between space weather and marine predator migrations?

Dr Stefan Lotz¹, Dr Mia Wege², Dr Pierre Cilliers¹

¹SANSA, Hermanus, South Africa. ²University of Pretoria, Pretoria, South Africa

Abstract

The negative influence of anthropogenic and other external factors on the behaviour of marine animals is an open question in marine biology, with the cause of mass strandings of mammals a particularly important topic. One cause of anomalous behaviour may be due to sudden perturbations to the geomagnetic field and increases in the electromagnetic noise levels caused by solar electromagnetic activity -- eruptions of plasma on the solar surface that may significantly disturb the global geomagnetic field for several days and increase electromagnetic radiation over a wide spectral range. It is postulated that the changes in geomagnetic field orientation and radiation noise can disrupt the so-called biological compass [1].

In this study we compare high resolution global geomagnetic activity indices and solar radio burst measurements with the Retrospective Analysis of Antarctic Tracking Data set (RAATD) [2] to find whether a statistically significant link exists between animal movement and space weather. The RAATD set contains tracking data from 1991-2016 for 17 different marine predator species. This data will be compared with geomagnetic indices and solar radio bursts covering the same period - approximately solar cycles 22-24. The indices are calculated from global networks geomagnetic observatories and estimate different aspects of geomagnetic activity, such as ring current strength (Dst index) or auroral electrojet intensity (AE index), and a global network of solar radio spectrometers (e-Callisto network).

We will report on the findings of this interdisciplinary study.

References

https://doi.org/10.1016/j.cub.2020.01.028
https://doi.org/10.1038/s41597-020-0406-x

1049

Contribution of the Biological Pump to the Flux of Persistent Organic Pollutants in the Water Column in Antarctic Coastal Ecosystems.

Ms. Andrea Hirmas^1,2,3, Dr. Gustavo Chiang¹, Dr. Cristóbal Galbán^2,3, Dra. Victoria Gómez², Dra. Thais Luarte^1,2,3, Dra. Karla Pozo^4,5, Dra. Petra Pybrylova⁵

¹Departamento de Ecología y Biodiversidad, Universidad Andrés Bello, Santiago, Chile. ²Centro de Genómica, Ecología y Medioambiente GEMA, Universidad Mayor, Santiago, Chile. ³Anillo en ciencia y Tecnología Antártica, POLARIX, Santiago, Chile. ⁴Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Concepción, Chile. ⁵Research Center for Toxic Compounds in the Environment (RECETOX), Masaryk University, Brno, Czech Republic

Abstract

Industrial development over the last century has had a notable impact on Antarctic ecosystems by releasing persistent organic pollutants (POPs) into the atmosphere. These POPs are persistent, semivolatile and can be transported over long distances reaching the polar regions. They can bioaccumulate and biomagnify in food webs, producing toxic effects on biota. Few studies have considered these oceanographic processes in the water column and their relationship with the dynamics and flux of POPs in polar environments, especially in Antarctica. Considering the processes that make up the biological pump in the flow of POPs in the water column and in the food webs is important due to the role that phytoplankton plays in these processes. A representative of POPs are polybrominated diphenyl ethers (PBDEs) (flame retardants) and their presence in Antarctic biota at lower trophic levels has been barely studied. The hypothesis and objectives of this work focus on detecting the contribution of the biological pump to the availability of POPs in the water column, through the collection of water samples, particulate organic matter in sedimentation, phyto and zooplankton. 10 PBDEs congeners were detected where bioaccumulation was less than expected based on the physicochemical properties of the compounds and the water temperature. The biomagnification factor indicated that congeners with higher LogKow do not increase their concentration between trophic levels. The combination of the data collected in this study allowed us to conclude that the PBDEs could be sedimenting associated with organic matter at the bottom of the sea, so, contrary to what was assumed, the biological pump will not allow greater bioavailability of PBDEs for the organisms in the water column, and allowed us to investigate other possible routes of the flow of these contaminants in Antarctic coastal ecosystems.

1050

Influence of bird activity on soil chemistry in maritime Antarctica

Amanda Melissa Pessoa Lopes¹, Iorrana Figueiredo Sacramento¹, PhD William Fortes Rodrigues², Full professor Fábio Soares de Oliveira³, Full professor Carlos E.G.R. Schaefer¹

¹Federal University of Viçosa, Viçosa, Brazil. ²SEDU - Prefeitura de Juatuba, Juatuba, Brazil. ³Federal University of Minas Gerais, Belo Horizonte, Brazil

Abstract

Bird activity in Antarctic soils, facilitated by nutrient-rich guano deposition, enhances weathering processes. Both flying and non-flying birds, such as petrels and penguins, contribute to the formation of ornithogenic soils on maritime Antarctic islands. These soils' chemical properties are influenced by various factors, including bird species, parent material, topography, and vegetation cover. Our study aimed to compare soil chemical characteristics influenced by petrels and penguins, considering active (current bird occupation areas) and inactive (past bird occupation areas) influences. We collected and analyzed 18 soil profiles from Harmony Point, Nelson Island. We employed descriptive statistics and principal component analysis (PCA) to understand the main relationships between soil chemical attributes. The first two PCA dimensions explained 71% of the total data variance. Soils under active penguin influence were affected by PBS, water pH, and P, reflecting intense guano input and marine influence. Conversely, soils under inactive penguin influence showed no distinct characteristics, influenced by base cations, water pH, TOC, and Al3+. Soils under inactive petrel influence tended to be more acidic, while those under active petrel influence were more diverse, affected by various factors such as Alsat, Al3+, H+Al, TOC, pCEC, and base sum. Active bird influence, whether from petrels or penguins, increased soil alkalinity and fertility compared to inactive influence. However, petrel-influenced soils had lower P content due to less nutrient-rich guano and smaller nesting populations compared to penguin colonies. Additionally, higher TOC values in petrel-influenced soils, especially those actively influenced, suggested vegetation development near petrel nests due to nutrient leaching. Next to penguin colonies, vegetation growth was limited due to trampling. Bird behavior, combined with topographic conditions, significantly shapes the chemical characteristics of ornithogenic soils in maritime Antarctica.

1051

Response of carbon burial to variation of phytoplankton around Antarctica

Dr Xuejiao Wang

Polar Research Institute of China, Shanghai, China

Abstract

An essential role is played by Antarctic in carbon sinking that the Southern Ocean accouts for more than 40% of the cumulative global ocean uptake of anthropogenic CO₂. Phytoplankton composing by coccolithophores and diatoms is the primary production to transform carbon dioxite preserved in deep ocean through photosynthesis. Different from the carbonate skeletons produced by coccolithophores, diatoms with opal skeletons are gradually dominated in Antarctic since Miocene. As well known, coccolithophores survive in warm and low-latitude area while diatoms adapt to high-latitude area and cold upwelling, then bloomed by high availability of iron and silicon during glacial period. Hence, the constitute of phytoplankton is a vital part to discuss the contribution of carbon sinking. Here, we provide the data of microfossils in Antarctic and calculate the data of phytoplankton productivity. The samples are colledcted mainly in Ross Sea and Amundsen Sea in Holecene sediments and analyzed according to regular method under microscope to provide quantitative results. Futhermore we test the salinity, alkalinity and sea surface temperature. Abundant and high-diversity diatoms are identified while a few calcareous nannofossils and several foraminifera occur in Ross Sea mainly. Controlled by variation of water conditions and temperature, the carbon skeletons is distributed in layers which might be corrolated with the seansonal rotation and terrestrial input. The abundant diatoms indicate that it is contribute mostly to transform CO₂ in Antarctic in Quaternary. And coccolithophores promote the carbon sinking basing on the contibution of diatoms, the survival of coccolithophores are always along with abundant of diatoms that is dominant in Quaternary in Antarctic. And foraminifera produce the carbonate skeletons and carbon dioxiteat the same time, which is proposed to affect the carbon sinking less for the lower amount and balance of carbon cycle.

1055

Pleistocene evolution of Ninnis and Cook glaciers (East Antarctica) from a micropaleontological and sedimentological study: Preliminary result.

Fiorenza Torricella^1,2, Francesca Battaglia¹, Andrea Caburlotto², Ester Colizza³, Xavier Crosta⁴, Andrea Gallerani⁵, Johan Etourneau^4,6, Amy Leventer⁷, Romana Melis³, Gianguido Salvi³, Tommaso Tesi¹, Patrizia Macrì⁸, Matteo Perotti⁹, Luca Zurli⁹, Sergio Andò¹⁰, Torben Gentz¹¹, Laura De Santis²

¹Istituto di Scienze Polari- CNR, Bologna, Italy. ²Istituto di Oceanografia e Geofisica Applicata-OGS, Trieste, Italy. ³Dipartimento di Matematica, Informatica e Geoscienze, Università degli Studi di Trieste, Trieste, Italy. ⁴Univ. Bordeaux, CNRS, Bordeaux INP, EPOC, Bordeaux, France. ⁵Istituto di Scienze del Mare - CNR, Bologna, Italy. ⁶EPHE/PSL Research University, Paris, France. ⁷Department of Geology to Department of Earth and Environmental Geosciences, Hamilton, New York, USA. ⁸Istituto Nazionale di Geofisica e Vulcanalogia, INGV, Roma, Italy. ⁹University of Siena, Department of Physical, Earth, and Environmental Sciences, Siena, Italy. ¹⁰Department of Earth and Environmental Sciences, University of Milano Bicocca, Milano, Italy. ¹¹Alfred Wegener Institute Helmholtz Centre for Polar- and Marine Research, Bremerhaven, Germany

Abstract

The Cook Ice Shelf and Ninnis Glacier drain a large part of the Wilkes Land Basin, which contains the equivalent of about 4 metres of sea level. The glaciers in this region are thought to have retreated during the warm climatic phases of the Pleistocene, but the extent of the retreat and the identification of the driving forces are still controversial. The aim of this study is to contribute to the understanding of regional depositional processes and environmental conditions that shed light on the dynamics of the ice sheet and the factors that determine its stability (ocean and atmospheric temperatures and precipitation), and ultimately to refine the projected evolution of these glaciers. We here present the preliminary results of a multidisciplinary study (textural analyses, geochemical, chemical and petrographic analyses, paleomagnetic and micropaleontological determinations) carried out on six sediment cores collected on the continental slope off the Cook Ice Shelf and Ninnis Glacier in the framework of the Programma Nazionale di Ricerca in Antartide - PNRA project COLLAPSE ("Cook glacier-Ocean system, sea LeveL and Antarctic Past Stability'). The preliminary results allow to identify three main units: the first unit consists of laminated silt with low microfossil content and is interpreted as influenced by bottom current; the second unit is a massive silt with ice debris, and very low microfossil content and is interpreted as indicating a period with intense ice calving with iceberg production; the third unit is a bioturbated mud with high microfossil content which allows to recognize the main climatic events during the late Pleistocene (from MIS 5 to presents).

1056

Multi-year observation of physical parameters along the Ross Ice Shelf

Angela Garzia^1,2, Pierpaolo Falco², Naomi Krauzig², Pasquale Castagno³, Giorgio Budillon⁴, Enrico Zambianchi⁴

¹La Sapienza University of Rome, Rome, Italy. ²Marche Polytechnic University, Ancona, Italy. ³University of Messina, Messina, Italy. ⁴Parthenope University of Naples, Naples, Italy

Abstract

The Ross Ice Shelf (RIS) in Antarctica is the largest ice shelf in the world and plays a key role in stabilizing the Antarctic ice sheet and in regulating its contribution to global sea level. As well as being important for its potential impact on sea-level rise and its response to ongoing climate change, this area experiences significant processes, such as ice-ocean interactions and the formation of Ice Shelf Water; this last is the coldest water mass in the world and contributes to the production of the Antarctic Bottom Water, which is a key element in the Meridional Overturning Circulation and in the ventilation of the deep ocean layers.

In this study, we present results from multi-year observations of physical parameters along the Ross Ice Shelf, by the use of austral summer measurements collected over several years during the Italian National Antarctic Research Program (PNRA) expeditions. CTD and LADCP data from 1995 to 2024 have been used, providing an overview of interannual variations in the physical properties of the water column along the RIS. Together with the characterisation of the water masses in the western, central and eastern sectors of the RIS, the time series analysis of thermohaline features of main water bodies has been performed. Furthermore, the ocean heat content, the basal melt rate and freshwater content have been estimated from temperature and salinity profiles along the RIS over the entire period, in order to elucidate long-term trends and patterns, and to identify potential drivers of the temporal variability. Thanks to these insights gained from multi-year observations, we aim to contribute to ongoing efforts to monitor and better understand the water mass dynamics of the Ross Ice Shelf in the context of a changing climate.

1064

Analysis of the spectral response of volcanic soils of the Penguin Island, Maritime Antarctica

Amanda Melissa Pessoa Lopes, Isabelle de Angeli Oliveira, PhD Rafael Gomes Siqueira, Full professor Márcio Rocha Francelino, Full professor Elpídio Inácio Fernandes-Filho, Full professor Carlos E.G.R. Schaefer

Federal University of Viçosa, Viçosa, Brazil

Abstract

Located in Maritime Antarctica, Penguin Island is an area of recent volcanism and is part of the range of slightly alkaline volcanic rocks. The products of volcanic eruptions are mainly represented by pyroclasts of basaltic and basalt-andesitic compositions. These geological features represent distinct natural resources in soils, which is expressed in their mineralogy and physical characteristics. The present study aimed to evaluate the spectral responses of the volcanic soils of Penguin Island. A total of 6 samples (all classified as C horizons) from 2 soil profiles were analyzed using the ASD FieldSpec® 4 Hi-Res spectroradiometer. All samples presented sandy texture, being differentiated in three groups according to the color of the ashes. All soils presented lower reflectance values in the Visible range (400 ~ 700 nm) and higher values in the SWIR (mainly 2000 ~ 2500 nm). The darker soils (rich in Fe²+) had the lower reflectance in all spectra due to the lowest albedo, with values always below 15%. The grayish soils showed the highest reflectance values in the Visible, with high slope up to the Vis-NIR region (23%). Ahead, the increase is gentle, reaching 25% at the end of NIR. The reddish soils showed greater variations in the curves, with the highest inflexion after the Red region and mainly in the Vis-NIR (with reflectance of 20%) due to the strong presence of iron oxides. After that, the reflection keeps on a strong increase, reaching 40-50% in the SWIR. Although the distinct reflectance, there is a trend in the curves’ slopes and depressions, probably due to similar soil composition and origin. The samples analyzed demonstrated spectral responses based on their mineralogical and geological characteristics. In addition, the distinction in color was not just reflected in the Visible, but also in all NIR, what has implications for soils remote imagery.

1065

Critical analysis of Brazilian Antarctic Program investments in logistical aspects, science and prevention

Dr/ ECR Paola Barros-Delben^1,2,3, Dr Danielle Jacon Ayres Pinto (UFSC)¹, Dr Pedro Marques-Quinteiro⁴, Studant/ ECR Raphael Fernandes Vieira Moreira Gonzaga^5,2, Dr Marcos Antonio do Nascimento⁶, Dr. Guilherme Lopes da Cunha⁷, Dr. José Roberto Pinho de Andrade Lima⁷, Dr. Roberto Moraes Cruz¹, Dr. Hugo Alves Mariz de Moraes⁸, Dr. Paulo Câmara⁷

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²APECS-Brazil, Belo Horizonte, Brazil. ³Polar Sapiens, Florianópolis, Brazil. ⁴Lusófona, Lisboa, Portugal. ⁵Universidad de La Plata, La Plata, Argentina. ⁶Federal University of Maranhão, São Luís, Brazil. ⁷Escola Superior de Defesa, Brasília, Brazil. ⁸Federal University of Pernambuco, Recife, Brazil

Abstract

In 2012, the Brazilian Antarctic Program (PROANTAR)' Comandante Ferraz Antarctic Station (EACF) was destroyed in a fire. The budget foreseen for PROANTAR, however, focused in preventive measures for risks of fires only, but faced the incident with the skidding of an C130 aircraft on the Chilean runway in Antarctic Chilean base Frei in 2015, incidence of numerous illnesses, accidents and evacuations, and crises, such as the situation of harassment judged in 2023 involving military personnel in the EACF. The following projects are completed and under development, according to public data made available in reports: EACF rebuilding ($99.6 million), opened in 2020; the KC-360 aircraft ($4.5 billion); project of the new vessel NApAnt ($100 million). Brazil's annual investments in Antarctica did not exceed US$28 million, added to parliamentary amendments, which in 2022 was US$3 million. Of the amount, only US$1 million is for logistical support for research and operations projects and a mere US$100 thousand was allocated to logistical support flights, limited to winter operations since 2019, after the replacing the C-130 Hercules aircraft, significantly reducing researchers into the field during the summer. Groups of up to around 20 researchers are only transported on ship crossings, as the new aircraft does not yet land in Antarctica. In 2023, the largest budget to support for research in 4 decades of Brazilian presence in Antarctica was enunciated, US$6 million for projects in 4 years of execution, which corresponds to 4% of the entire annual recent, formal and exceptional budget available. Investments in prevention would be equivalent to less than 1% of all annual spending. The questions on the agenda are: the strategic direction of resources for PROANTAR; the priority of scientific research and; the health and safety of expeditioners in the short, medium and long term.

1066

Generating Novel Digital Soil Maps for the Southern Circumpolar Region using a Collaborative Point Database and Ensemble Machine Learning Predictions

Dr. Nicolas Jelinski¹, Dr. Mauro Guglielmin²

¹University of Minnesota, Saint Paul, MN, USA. ²Università degli Studi dell'Insubria, Varese, Italy

Abstract

The southern circumpolar region has been largely neglected in global soil mapping efforts, despite the existence of a significant amount of soil data and improved geospatial information for generating covariates. To address this gap, we propose the development of a harmonized point database of soil observations in the southern circumpolar region specifically for digital soil mapping, leveraging the work of the ANTPAS (Antarctic Permafrost and Soils) project. We suggest utilizing ensemble predictions from machine learning approaches to generate novel, high-resolution digital soil maps for the southern circumpolar region. These ensemble-based digital soil maps will provide valuable insights into the spatial distribution and characteristics of soils in Antarctica, contributing to a better understanding of the region's ecosystems, carbon storage potential, and response to climate change. This initiative represents a significant step forward in addressing the current shortcomings in Antarctic and southern circumpolar soil mapping (relative to northern circumpolar efforts) and showcases the potential of ANTPAS data to improve knowledge of Antarctic soils and permafrost. The proposed approach emphasizes the importance of international collaboration, data sharing, and innovative modeling strategies in advancing our understanding of this critical region and would represent a timely initiative which could build on similar initiatives in Alaska and the northern circumpolar region..

1071

Soils impacted by Pygoscelis penguins as a reservoir of microorganisms with the potential to degrade anthropogenic pollutants

Claudio Valenzuela^1,2, Alexander Marin^1,2, Katerin Almendras^1,2, Léa Cabrol^1,3, Julieta Orlando^1,2

¹Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Santiago, Chile. ²Universidad de Chile, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Santiago, Chile. ³Aix Marseille University, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France

Abstract

Antarctica stands out as one of the most extreme environments in the world, where human activity, though limited, exerts a significant local impact. Human presence on this continent contributes to pollution through incidents like oil spills and routine activities such as wastewater disposal, releasing anthropogenic pollutants like oil-derived hydrocarbons, microplastics, and persistent organic pollutants. These pollutants accumulate in the environment and organisms like penguins, crucial components of Antarctic biodiversity. While nesting, penguins can transport these anthropogenic pollutants to the soil, thereby influencing the microbiota. This study aims to analyze the metagenomes of soils from Pygoscelis penguin colonies in the Antarctic Peninsula, focusing on genes encoding enzymes associated with the biodegradation of specific anthropogenic pollutants, including naphthalene, polystyrene, polyethylene terephthalate, and polychlorinated biphenyls. These genes were quantified by comparing metagenomic reads with data from customized databases created to detect genes encoding these enzymes. Our findings reveal the presence of genes encoding enzymes capable of degrading these contaminants, particularly those associated with naphthalene degradation, exhibiting varied abundance across the studied soils. Sequences of interest are predicted to belong mainly to microorganisms from Actinomycetota and Pseudomonadota phyla. Interestingly, a comparison between the abundance of these genes and the proximity to the nearest human settlement shows no correlation, suggesting that the potential of microorganisms to degrade these contaminants may not be significantly influenced by human presence. Further analysis will involve examining metagenome-assembled genomes (MAGs) to comprehensively characterize the microorganisms with the potential degradative capacities of interest. Soils exhibiting higher abundance could potentially serve as reservoirs for microorganisms proficient in degrading these pollutants, presenting promising avenues for future bioremediation strategies targeted at the Antarctic region.

Funding: ANID – Programa Iniciativa Científica Milenio – ICN2021_002, FONDECYT 1241787, ANID-Subdirección de Capital Humano/Doctorado Nacional/2022-21221205

1073

System and methodology for a mental health care program and safe behavior for difficult-to-access contexts

Dr./ ECR Paola Barros-Delben^1,2,3,4, Dr. Pedro Marques-Quinteiro⁵, Dr. Roberto Moraes Cruz¹

¹Federal University of Santa Catarina, Florianópolis, Brazil. ²South of Brazil University, Palhoça, Brazil. ³APECS-Brasil, Belo Horizonte, Brazil. ⁴Polar Sapiens, Florianópolis, Brazil. ⁵Lusófona, Lisboa, Portugal

Abstract

Difficult-to-access contexts, such as isolated, confined, and extreme environments (ICE), polar regions, oil platforms, space stations, or space analogs require strategic planning that guarantees the health and safety of all people involved in the activities. Investments in programs and other technologies aimed at ensuring fewer impacts and reducing the risk of accidents, illnesses, and crises, as well as evacuations, are promising, with scientific, environmental, social, and economic repercussions. The objective of this study was to describe a system and methodology for a mental health care and safe behavior program for difficult-to-access contexts. The construction of the system and method was carried out based on field experiences on 7 occasions in Antarctica (2014 to 2019), survey (n=50), and interviews (n=18) in digital mode with a qualitative approach, considering the pre-expedition with experts from different areas of health and polar science. The results of these efforts are a specification of a broad health and safety care program that encompasses psychological, psychophysiological, and psychosocial protocols in detail for its implementation and validation in 5 phases: characterization of the context; assessment, preparation, activity, and post-activity. The results indicate a simplified system with standardized application, which guarantees greater control of indicators for predictive analysis, to prevent undesirable events and suitability criteria or recommendations. Also, the high acceptability of the proposal (100%) among people who go to health contexts or professionals, requesting both exams, tests, and training before expeditions as necessary. There were frequent concerns about voluntary adherence to the program, costs, and data security. Using the program in real contexts will allow fine adjustments to procedures for its continuity and the possibility of enhancing rapid responses to emergencies, a crucial factor in safeguarding lives.

1074

Phylogeographical patterns in Laevilacunaria antarctica (Gastropoda: Laevilitorininae) across its distribution in maritime Antarctica and South Georgia

Dr. Claudio González-Wevar^1,2,3, Mrs Yarleth Poveda¹, Mr Andreas Schmider-Martínez¹, Mg. Sc. Sebastián Rosenfeld², Dr Claudia Maturna², Dr. Karin Gérard^4,2, Dr. Hamish Spencer⁵, Dr. Elie Poulin^2,6

Abstract

How the nearshore marine benthic communities survived Quaternary glaciations in Antarctic and associated areas is a major question in the biogeography of the Southern Ocean. Nearshore species with low dispersal potential are expected to to harbour marked genetic structure or even the presence of separate cryptic species, due to their survival in small refugia subjected to repeated bottlenecks. Here, we performed population-based analyses in the littorinid Laevilacunaria antarctica across maritime Antarctica and South Georgia. The species exhibit low autonomous vagility, benthic protected development but lives closely associated to macroalgae. Populations of L. antarctica exhibited very low levels of genetic diversity and contrary to our expectations it includes a single unstructured population across maritime Antarctica with a typical high-dispersal star-like, short-branched genealogy and includes a dominant broadly distributed haplotype. The South Georgia population, however, consists of a separate populational unit, strongly differentiated from those of the maritime Antarctica. Divergence time estimations suggest that these two genetic groups were separated approximately 1.2 million years ago, long before the Last Glacial Maximum and evolved independently in these areas. On a wider geographica scale (maritime Antarctics vs South Georgia), our results in L. antarctica provide support for the expectations for a near-shore marine benthic species with low dispersal potential. However, on a narrower geographic scale (within maritime Antarctica) life-history characteristics including the close affinity of the species with macroalgae, would allow dispersal of the species which exhibits paradoxically an absence of genetic structure across hundreds of kilometers, probably mediated by rafting.

1075

Systematic conservation planning for seabirds and marine mammals in east Antarctica.

Dr Anant Pande

Wildlife Conservation Society - India, Bengaluru, India. Wildlife Institute of India, Dehradun, India

Abstract

India has been a part of the Antarctic treaty for over 40 years now. Given the country’s long presence in the continent, it’s imperative to develop a long-term strategy to better understand the biodiversity of the region where the Indian Antarctic Program operates, detect changes in populations and ensure sustainable human activities in Antarctica. Vertebrates such as seabirds and marine mammals act as sentinels for the fragile Antarctic ecosystem. This study was initiated under the “Antarctic Wildlife Monitoring Program” to develop strong baselines on vertebrates in east Antarctica and inform conservation management through systematic conservation planning.

This program, over a period spanning 11 years, targeted pelagic seabirds and marine mammals in the Southern Ocean, focusing on estimating abundance, mapping distribution patterns, monitoring breeding behavior, and assessing genetic connectivity. Surveys were conducted utilizing vessel-based, aerial (helicopter and UAVs) and on-ground methods. Further, use of advanced monitoring tools such as automated nest cameras and drones was employed to collect targeted data on select species such as snow petrels (breeding biology, genetics) and Adelie penguins (colony counts, distribution). It generated a strong baseline on seabird distribution (nesting and moulting areas), seals and whales’ distribution in the east Antarctic sector. Snow petrel colonies were selected for long-term nest monitoring to cover complete breeding phenology of the species. Intensive monitoring of nesting behaviour and a systematic genetic sampling (including Wilson’s storm-petrel) provided crucial ecological information.

Long-term monitoring (> 10-20 years) is planned to ensure sustainable human activities and understand climate change impacts on vertebrate populations in Antarctica. Further, systematic conservation planning approach is discussed for the east Antarctic sector to enable data-sharing and collaborations for the region.

1079

Spatial and temporal characterization of dominant tidal constituents in direct sea level observations along the western Antarctic Peninsula (WAP)

Jennifer Villarroel Nenen¹, Dr. Andrea Piñones^2,3,4,5

¹Department of Geophysics, University of Concepcion, Concepción, Chile. ²Austral University of Southern Chile, Valdivia, Chile. ³IDEAL Center, Valdivia, Chile. ⁴COPAS COASTAL, Concepción, Chile. ⁵Millenium Institute Biodiversity of Antarctic and Subantarctic Ecosystems, Concepción, Chile

Abstract

Tidal observations in Antarctica are scarce, with most of the observations corresponding to records from the austral summer. Research has mainly focused on the region of the Bransfield Strait, leading to less documentation of the tidal regime along the western Antarctic Peninsula (AP). This study aims to expand geographically the tidal study of the AP by adding high-frequency direct observation analysis with periods exceeding one year from stations located south of the Bransfield Strait. Tidal constituents corresponding to 6 tidal stations located from the north of the WAP to Marguerite Bay were analyzed. The data correspond to sea level records with duration of over a year at hourly frequency. All time series were analyzed using a harmonic analysis, this analysis provided a list of tidal components, tidal amplitude and identified the dominant tidal constituents. Through the harmonic analysis, 59 constituents per tidal station were obtained. The dominant main constituents (K1, O1, M2, and S2) were analyzed to obtain the corresponding tidal regime and calculate the energy contributed by each constituent to the tidal wave. The results showed that from the north to the south of the AP, there is an increase in the form factor, indicating a gradual change of the tidal regime, from a mixed semidiurnal regime to a mixed diurnal one, with Faraday Station (65.25°S, 64.26°W) being a turning point, where diurnal constituents begin to decrease along with the semidiurnal ones but more rapidly. The amplitudes and phases obtained showed uniformity and agreement with previous harmonic analyses conducted north of the AP, supporting the methodology applied to the rest of the sea level records along the Antarctic Peninsula. These results were used to validate the impact of tidal dynamics in a high-resolution ocean circulation model implemented for the western AP.

1080

Lithospheric Structure and Deformation of Antarctica: Insights from Geophysical and Geodetic Measurements

Dr Ravikumar Muppidi

CSIR NATIONAL GEOPHYSICAL RESEARCH INSTITUTE, Hyderabad, India

Abstract

Knowledge of the thermal state and mechanical properties of the lithosphere is important for many Geophysical and Geodetic applications. The thermal and compositional structure of the lithosphere controls to a large extent the initiation and evolution of tectonic deformation processes. These parameters are also required to model vertical motions at the Earth's surface, such as glacial isostatic adjustment (GIA), which are of prime importance in monitoring the mass balance of the Antarctic ice sheet. We computed new crustal and lithospheric thickness maps based on integrated modeling of elevation, geoid, gravity and thermal analysis. This approach assumes local isostasy, thermal study state, and linear density increase with depth in the crust and temperature-dependent density in the lithospheric mantle. And these results are compiled by seismic Moho and tomographic models related to LAB depth. Our new lithospheric thickness map derived from 3D inversion of the lithospheric gravity field component brings out distinct features like the thickening of the lithosphere in the east and the thinning of the lithosphere in the west of Antarctica. The effective elastic thickness (Te) as a proxy for the strength of the lithosphere and Te results also confirm a clear tectonic division of Antarctica with predominantly high values in East Antarctica (EANT) and low values in West Antarctica (WANT).

In WANT, there is a weak Earth structure with a thin lithosphere and low-viscosity upper mantle, while the opposite structure exists in EANT. The Global Navigation Satellite System time series and Gravity Recovery and Climate Experiment data show that there are high rates of land vertical uplift in WANT and low uplift rates in the Trans Antarctic Mountain and EANT regions. The patterns in crustal deformation match lateral variations in density, seismic velocities, heat flow and earth structure, emphasizing the need for 3D earth models to understand GIA in Antarctica.

1081

40 years of operations of the Brazilian Air Force: experience report in Polar Psychology research

Dr. Paola Barros-Delben

Federal University of Santa Catarina, Florianópolis, Brazil. APECS-Brazil, Belo Horizonte, Brazil. Polar Sapiens, Florianópolis, Brazil

Abstract

In 2016, the first civilian woman was on a winter flight to launch cargo in Antarctica by the Brazilian Air Force (FAB), which completed 40 years of supporting the operations of the Brazilian Antarctic Program (PROANTAR) in 2023. It was an opportunity to explore methodological limits and potential aspects in polar psychology, accompanied by discussions on technical observations for developing research questions, only possible with a presence on site. Aboard the Hércules C-130 plane, which retired in Brazil in 2024 and was replaced by the KC-390 aircraft, the researcher had to wear a jumpsuit attached to steel cables to the ceiling, to walk in the space configured to transport loads, pushed by the masters toward reach the target nailed to the frozen ground by the base group at the Comandante Ferraz Antarctic Station (EACF). As the location of the Brazilian station does not allow vessels to approach in winter, it is from the cargo launches that the memberships who competed for one of the 15 places to remain on mission for 13 months receive supplies and priority cargo: letters and gifts from family and friends. The item of affection is prepared the night and early morning, a process observed in 2019 when boxes that hold up and are attached to the parachute for uneventful arrival. Pilots take turns in activities that require concentrated attention and face physical and mental fatigue for visual tasks that also require calculations and a lot of training, which is not always possible due to the tight schedule and restricted budget. The unique experience guaranteed a photographic narrative and the humanization of those who provide services that are often anonymous, but fundamental to polar operations, in addition to objective understanding for directing unique resources for the continuity of polar air operations.

1083

Facilitating Worldwide Collaborations in the Geospace Dynamics Constellation (GDC) Era

Bea Gallardo-Lacourt^1,2, Doug Rowland¹, Larry Kepko¹, Katherine Garcia-Sage¹

¹NASA/GSFC, Greenbelt, MD, USA. ²CUA, Washington DC, USA

Abstract

The Geospace Dynamics Constellation (GDC) is NASA’s upcoming heliophysics mission. GDC is a community mission composed of six satellites. It aims to serve as a focal point for coordinated ionosphere-thermosphere-mesosphere (ITM) science on a global scale. This coordination will involve the collaboration of space-based and ground-based assets, simulations, and theory, all operating under the umbrella of the “ITM Great Observatory.”

Recognizing the importance of synergy between GDC and the international community’s ground-based assets, the GDC science team has established a community group. This group serves as a nexus, offering ground-based observers valuable insights into the GDC mission and its scientific objectives. Furthermore, facilitates the coordination of ground-based efforts, ensuring that GDC measurements are leveraged to augment broader ITM science goals.

GDC is currently seeking international scientific collaborations, particularly in ground-based observations that can leverage GDC measurements to address important science investigations. In essence, the GDC mission represents an exciting opportunity for global collaboration in the field of ITM science.

1084

“Under Pressure”: Understanding Stress Gradients and Microbial Biodiversity in the Antarctic Dry Valleys

Catherine Clive¹, Jesse Jorna¹, Dr Byron Adams^1,2

¹Department of Biology, Brigham Young University, Provo, USA. ²Monte L. Bean Life Science Museum, Brigham Young University, Provo, USA

Abstract

The Antarctic dry valleys are an excellent model system to understand the role of stress gradients in structuring microbial communities because of their low biodiversity and strong environmental drivers. Stress has crucial effects on microbial biodiversity and the functioning of the ecosystem such as nutrient cycling and energy flow within the environment, but the nature of these effects on taxonomic and phylogenetic diversity isn’t well known. We hypothesize that taxonomic and phylogenetic diversity decrease at higher elevation, and in more basic soils due to the increase in physical stress. We further expect that the presence of moss will lead to an increase in diversity because of the possibility of symbiotic interactions. We used DNA metabarcoding of the 16S gene to construct relative biodiversity matrices of microbial communities along multiple stress gradients. We took samples from various elevations, at various soil pH, and with or without living moss to study environments of increasing stress. These biodiversity matrices suggest that the presence of increased stress on microbial communities leads to a decrease in taxonomic and phylogenetic biodiversity, likely because only the most adapted microbes can survive in a harsher environment. In addition, we were able to demonstrate the importance of biotic interactions in decreasing stress on microbial communities and allowing for greater microbial biodiversity. By better understanding how stressors can directly affect these microbial communities, we are able to better understand how the microbes themselves affect the functioning of the ecosystem. These findings help us to better understand the effects of stress on microbial communities and are the first findings that hint at the importance of aboveground-belowground biotic interactions on microbial soil biodiversity in the Antarctic Dry Valleys.

1085

Refractory black carbon (rBC) ice core record from the Quelccaya Ice Cap, Peru

Ms. Manoela Portella¹, Mr. João Ilha², Mr. Jefferson Simões¹

¹Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Università Ca' Foscari, Venezia, Italy

Abstract

Black carbon (BC) is an important climate-forcing agent characterized by strong absorption of visible light and resistance to chemical transformations. BC particles emitted from biomass burning in the Amazon Basin have the potential to deeply affect Andean Glaciers, reducing the snow albedo and ultimately accelerating snow and ice melting. To assess the effects of this aerosol on the cryosphere, a 128.3 m long ice core was collected in the Quelccaya Ice Cap, Peru (at 13°55’46,099”S, 70°49’21,557”W, 5.674 m above the sea level) during the austral winter of 2022. The expedition was part of a joint research between Climate Change Institute (USA), Centro Polar e Climático (Brazil) and Instituto Nacional de Investigacíon en Glaciares y Ecosistemas de Montaña (Peru). The core had its 153 sections of approximately 90 cm cut and prepared for BC analyses inside a certified cold room (‑20 °C) at the Climate Change Institute, University of Maine, USA. An extended‐range Single Particle Soot Photometer (SP2) coupled to a Marin‐5 nebulizer will be used to measure the refractory black carbon (rBC) mass and number size distributions through the core in the Department of Geological Sciences at the Central Washington University (USA). Particle trajectories from source areas to the drilling site will be simulated using the Hybrid Single Particle Lagrangian Integrated Trajectory (NOAA). The rBC results will also be compared to existing Andean and Antarctic BC records; to the El Niño Southern Oscillation and the Antarctic Oscillation indexes; and to fire spots reanalysis data from Global Fire Emission Database (GFED4.1s) and Programa Queimadas (INPE). This research aims to present the first black carbon record in the Quelccaya Ice Cap, contributing to the understanding of BC’s imprint on the Southern Hemisphere, such as possible changes in glaciers' mass balance and socioeconomic impacts on local communities.

1086

Sedimentary ancient DNA records the response of soft-tissue species to the Northern Antarctic Peninsula climate changes over the last thousand years

Ms. Manon Sabourdy¹, Ms. Mathilde Bourreau², Dr. Johan Etourneau^1,3, Dr. Xavier Crosta¹, Dr. Chris Bowler^2,4, M. José Utge⁵, Dr. Arnaud Huguet⁶, M. Vincent Klein⁷, Dr. Marie-Alexandrine Sicre⁷, Ms. Cecilia Morales Ocaña⁸, Dr. Francisco Jiménez-Espejo⁸, Dr. Dimitris Evangelinos⁹, Dr. Fernando Bohoyo¹⁰, Prof. Carlota Escutia⁸

¹UMR CNRS 5805 EPOC, Université de Bordeaux, Pessac, France. ²UMR CNRS 8197 IBENS, École Normale Supérieure, Department of Biology, Paris, France. ³EPHE-PSL Research University, Paris, France. ⁴Inserm U1024, Paris, France. ⁵UMR CNRS 7206, Eco-anthropologie, Muséum National d’Histoire Naturelle, Université Paris Diderot, Paris, France. ⁶UMR CNRS METIS, Sorbonne Université, Paris, France. ⁷UMR CNRS LOCEAN, Sorbonne Université, Paris, France. ⁸Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC, Universidad de Granada, Granada, Spain. ⁹Department of Earth Science and Engineering, Imperial College London, London, United Kingdom. ¹⁰CN Instituto Geologico y Minero de España (CSIC), Madrid, Spain

Abstract

The soft-tissue phytoplankton (such as cryptophytes, some haptophytes (e.g. Phaeocystis) and chlorophytes), can represent today up to 30% of the Southern Ocean (SO) phytoplankton biomass. These species might therefore play an important role in the carbon cycle but also in the SO food web as first trophic level. Despite their importance, we still ignore how they adapt to climate and environmental changes and how they compete with other phytoplankton species, especially against the dominant diatoms. Since these soft-tissue species do not produce any tests, conventional micropaleontological studies cannot be applied to investigate their response to past natural climate variability. Here, we used an innovative approach based on sedimentary ancient DNA (sedaDNA) preserved in the marine sediment core TG03 collected in the northern Antarctic Peninsula (NAP), to track their distribution and abundances at a multi-decadal timescale over the last millennia. We combined eukaryotic specific 18S rRNA sequences extracted from sedaDNA metagenomics shotgun data, with highly branched isoprenoids (HBIs) and GDGTs-derived sub-surface ocean temperatures (SOT-TEX₈₆^L and SOT-RI-OH)to determine respectively the response and adaptive processes of the soft-tissue groups to sea-ice and hydrological conditions. Our results indicate an alternation between warmer [2.5 – 7 °C] and colder [-1 – 2.5 °C] SOT that correlates (r_s= 0.5) with the absence (presence) of sea ice over the last millennia. The phytoplankton distribution, dominated by diatoms and cryptophytes, are simultaneous higher when oceanic subsurface temperature is warmer and ice-free. Both groups thrive in nutrient-rich surface meltwater, but cryptophytes prefer more stratified water masses contrary to diatoms, leading to a competition between these two main groups. Finally, the last decades recorded a shift from natural variability to the post-industrial period, with rising SOT (+2.5 °C) and increase of cryptophytes. This pattern demonstrates that the current warming already impacted the NAP biodiversity pattern and the regional trophic network.

1087

Assessing manifestations of the modern colonial era in ATS participation

Hayley Kwasniewski, Dr. Peyton Thomas, Vasco Chavez-Molina, Dr. Cassandra Brooks

University of Colorado, Boulder, USA

Abstract

The normative framing of Antarctica as a case of exceptional governance and scientific diplomacy is not without merit. However, special attention should be given to critiques of the Antarctic Treaty System (ATS). Significant work has analyzed the ATS’ exclusivity and high representation of wealthy Western countries, from the original 12 signatories to the 56 Treaty Parties today. Since many studies have tied economic development to colonial activity, we ask: Has the dynamic between colonialism and economic development manifested in ATS participation? Has it acted as a barrier to participation? This study takes a global focus, including countries that are party to the Treaty and those who are not. We analyzed economic development indicators from the World Bank to quantify wealth status; and colonial activity was defined by 1) territorial claims of land inhabited by people beyond the state and 2) national declarations of independence from colonizing countries to assess country participation. Metrics are constrained to modern times by restricting colonial activity to the chronology between New Imperialism and the Second Decolonization (defined here as 1870-present). We find that both wealth and ATS participation correlate with temporal proximity to colonial activity. Countries that have recently colonized other areas have greater wealth and ATS participation. Conversely, those recently declaring independence from colonial powers have less ATS participation. The intricacies of ATS inclusion, therefore, cannot be fully understood without considering the ramifications of the modern colonial era. Future work will investigate timelines associated with State-scale participation in the ATS to identify drivers that may facilitate participation. We also plan to identify the consequences of ATS exclusivity on the natural environment and scientific research. Furthermore, as scientists that have significant associations with Western countries, predominantly the U.S., we acknowledge our limited perspective on these issues and invite dialogue from the SCAR community and beyond.

1089

Individual-level differences in size drive movements and spatial segregation of a pelagic seabird

Dr Lucas Krüger

Punta Arenas, Punta Arenas, Chile

Abstract

Individual-level differences in size play a crucial role in shaping the movements and spatial segregation of sexually dimorphic pelagic seabirds. This study investigated how size influences the response of Southern giant petrels (Macronectes giganteus) to environmental conditions, particularly wind speed and direction, during foraging trips in the Maritime Antarctic Peninsula. Utilizing tracking data from 36 breeding individuals in two seasons, it was found that smaller males exhibited higher transit speeds in response to stronger winds, whereas females showed more efficient utilization of wind during transit independently of size. Additionally, smaller females engaged in longer foraging trips associated with higher chlorophyll-a concentrations, while larger females were associated with areas of sea ice. The results suggest that size-driven variability influences not only individual movement patterns but also spatial segregation within the same sex. These findings provide insights into the intricate relationship between size, environmental factors, and foraging behavior in pelagic seabirds, highlighting the importance of considering individual-level variability in understanding population dynamics and responses to environmental change. Understanding how individual differences in size shape seabird ecology is essential in the face of climate-induced alterations in wind patterns in the Southern Ocean

1090

EU-PolarNet 2 White Paper with 80 recommendations to strengthen international polar observations

Gael Lymer¹, Renuka Badhe², Pjotr Elshout², Jan René Larsen³, Hannele Savela⁴, Serge Scory¹, Vanessa Spadetto⁵

¹Royal Belgian Institute of Natural Sciences, Brussels, Belgium. ²European Polar Board, The Hague, Netherlands. ³Arctic Monitoring and Assessment Programme Secretariat, Tromsø, Norway. ⁴University of Oulu, Oulu, Finland. ⁵4PM srls, INTERACT Non-Profit Association, Brussels, Belgium

Abstract

Global climate change is manifesting with alarming speed and severity, but nowhere are these changes more pronounced than in the polar regions. Yet polar observations are currently sparse, with observing networks fragmented and lacking large-scale coordination. Identified gaps in current observation strategies open prospects for improvement in climate system understanding, funding strategies, polar data management, prioritisation of observation, and inclusivity in polar research.

This poster will introduce the EU-PolarNet2 (funded by the EU-H2020) White Paper delivered to the European Commission in March 2024, with 80 actionable policy-level recommendations to strengthen international polar observations. The primary objective is to enhance understanding of polar environmental changes and their effects on other areas of the Earth. With these concrete recommendations, the white paper aims to provide guidelines to increase cooperation in observing the polar regions and create a coordinated system for continuous, standardised data, transnational polar observation and research actions of high societal relevance, to support well-informed decision-making processes.

The topics of the recommendations encompass:

Addressing user, stakeholder and rightsholder needs
Strengthening data systems
Advancing infrastructures and technology
Enhancing funding mechanisms and fostering international cooperation
Establishing effective governance and organisational structures
Encouraging collaborative research efforts
Emphasising societal relevance

Each topic, or 'pillar,' identified represents an area of natural common interest between the Arctic and the Antarctic. The proposed strategy seeks to join and consolidate the best assets, expertise, experience, and networks of existing polar initiatives. This integration is designed to align with societal needs while ensuring a cooperative approach to polar observations.

This poster will be used as a basis to present the white paper and its recommendations, and how to concretely implement them and the development of sustainable and inclusive polar observations.

1096

2+1+2: ARGENTINA, BRAZIL, CHINA, DENMARK AND NORWAY IN ANTARCTIC GOVERNANCE

Msc Laura Urrejola Silveira¹, Dr Ana Flávia Barros-Platiau^1,2, Dr Johanne Døhlie Saltnes¹, Dr Niels Søndergaard¹, Dr Danielly Silva Ramos¹, Dr Carina Oliveira¹

¹University of Brasilia, Brasilia, Brazil. ²Superior Defence College, Brasilia, Brazil

Abstract

Argentina, Brazil, China, Denmark, and Norway are parties to the Antarctic Treaty System (ATS), but with very different profiles, interests and capabilities. Since we found no comparison among them, this research paper raised the question: who are they and what have they been doing in the ATS regime and the Southern Ocean? While Argentina self-declares she is a bicontinental country, Norway is a claimant state, but Denmark, China, and Brazil are non-claimants. The latter are members of the BASIC group (from the climate change negotiations) and the BRICS (for the reform of the global order). But Argentina does not participate in any relevant group, since Mercosur does not have a polar agenda. Denmark and Norway are Nordic countries and parties to the Arctic Council and the NATO (North Atlantic Treaty Alliance).

China, Denmark, and Norway have a “polar strategy”, including the Arctic. China even invested in building the Brazilian scientific station. Their respective funding of scientific research over the last twenty years and the maintenance of the scientific stations leads to the conclusion they have different but not divergent strategies. Nonetheless, they cooperate little in scientific projects, and China stands alone as a “patent giant”. Using a multi-dimensional analysis framework, encompassing: i) science and innovation capabilities; and ii) geopolitical considerations, this paper shows two results. First, China is an undisputed polar and oceanic power, but so are Denmark and Norway; therefore, it is expected that they will exert more pressure in future debates concerning biological and mineral resources exploitation, as well as navigation and tourism. As a consequence, the legacy of CRAMRA and the future of CCAMLR are not free from these countries' interests. Second, if Argentina and Brazil have the shared goal of keeping their current status and the ATS status quo, then what hampers their diplomatic cooperation?

1102

Virulent Escherichia coli bacteriophage from an ornithogenic habitat in East Antarctica.

Prof. Artemiy Goncharov^1,2, Dr Viktoria Kolodzhieva², Dr Daniil Azarov^2,1, Prof Batyrbek Aslanov²

¹Institute of experimental medicine, Saint-Petersburg, Russian Federation. ²North-West State Medical University named after I.I. Mechnikov, Saint-Petersburg, Russian Federation

Abstract

The study of the phylogeography of bacteriophages is of considerable medical importance, as it has been suggested that phages from remote habitats may have unique spectra of lytic activity [Castillo D., et.al., 2014]. We used a collection of 12 natural and clinical cultures of Escherichia coli to search for bacteriophages from different ornithogenic habitats in East Antarctica. 5 bacteriophages were isolated as a result of testing 32 faecal samples collected from Adelie penguin colonies on the Haswell Archipelago in February 2023. One of these, phita5_7, was characterised in this study. This phage has lytic activity against the ESBL-producing clinical strain E. coli CCUG 55972.

As a result of sequencing and annotation of the genome by the PHASTER service (https://phaster.ca / ), it was found that this bacteriophage has a genome size of 137.6Kb, does not carry the determinants of bacterial pathogenicity, the integrase genes; and is phylogenetically related to obligately virulent viruses of the genus Vequintavirus (with 96% similarity to Escherichia phage nimi (GenBank Acc. No. MN850626.1)). The prediction of the bacteriophage life cycle, carried out using the PhageScope platform (https://phagescope.deepomics.org ) , based on the correlation of its protein sequences with the corresponding sequences available in the database provided by this platform (873,718 phage genomes), also allowed this virus to be classified as virulent.

Viruses of the Vequintavirus genus are considered as promising for therapeutic phage cocktails due to their ability to effectively disrupt bacterial biofilms [Dalmasso M. et al., 2016].

The studies thus demonstrate the fundamental possibility of isolating bacteriophages with a virulent phenotype and therapeutic potential in biomaterial from the coastal areas of East Antarctica.

1104

Regime Complexes: Antarctic Science as a Key Driver for the Future We Want

Dr Carlos Henrique Tomé¹, Dr Carina Costa de Oliveira², Dr Ana Flávia Barros-Platiau^2,3

¹Federal Senate, Brasilia, Brazil. ²University of Brasilia, Brasilia, Brazil. ³Superior Defence College, Brasilia, Brazil

Abstract

There is a stark scientific consensus that Antarctica is key for the future we want. What happens in Antarctica affects the whole planet. Likewise, climate change has deeply affected Antarctica. Although diplomatic cooperation on climate change may, to some extent, shape the future reality (Figueres and Rivett-Carnac, 2021), diplomatic efforts to regulate the future of Antarctica and recognize the gravest scientific alerts are severely lagging behind (Polar Summit, 2024). Furthermore, an increasingly uncertain scenario is emerging, stemming from, among other factors, technological innovations and its consequences, for example, in geoengineering (Moore, 2024; Biermann et al, 2024), and digital sequencing information (DSI) (Novion, 2023). In this context, the global agenda offers an entirely new set of possible futures, especially due to the growing economic viability of activities such as bioprospecting, mining, and tourism. Assuming that one of the greatest challenges for the governance of the Antarctic regime stems from the complexity of the international system (Prantl and Goh, 2022), this paper addresses the following questions: Does the Antarctic Treaty System (ATS) have the legal tools to overcome these challenges? What aspects need to be revised? This research employs the conceptual and theoretical framework of regime complexes (Raustiala and Victor, 2004; Orsini et al, 2013; Gómez-Mera et al, 2020) to engage Antarctic science with the global diplomatic agenda. The investigation involves the regimes for Antarctica and the Arctic, the Convention On the Law of the Sea (UNCLOS), the new treaty on Conservation and Sustainable Use of Marine Biodiversity Beyond National Jurisdiction (BBNJ), and the International Seabed Authority's (ISA) deep-sea mining code. Therefore, it is not only a matter of legal tools, but of diplomatic recognition of the importance of Antarctica to future generations, and of Antarctic science as a key driver for the future, connecting the five regimes.

1105

Investigating the flow history of glaciers in the McMurdo Dry Valleys, Antarctica by fingerprinting glacial tills with provenance tools

Dr. Daniel Morgan¹, Dr. Rebekah Stanton¹, Dr. J. Warner Cribb², Payton Breitzmann¹, Ming Chen¹, Nadia McGlynn¹, Courtney Megerian¹, Lauren Lamson¹, Sophie Lopez¹, Zoe Storaasli¹

¹Vanderbilt University, Nashville, USA. ²Middle Tennessee State University, Murfreesboro, USA

Abstract

We use provenance tools to test for changes in the source area of glacial tills in the McMurdo Dry Valleys, Antarctica (MDV), which would indicate changes in the flow patterns of the glaciers that deposited them. By characterizing tills in the MDV with provenance tools, we will be able to ask questions such as: has the provenance changed over time? If so, have glacial flow patterns or glacial erosion potentially changed the provenance over time? How well correlated are tills of the same age in different valleys? How far into the MDV did the East Antarctic ice Sheet or the Ross Ice Sheet extend? Is there provenance information to support the over-riding of the Transantarctic Mountains in the Miocene or presence of fjords in the MDV during the Pliocene? To address these questions, we will determine the provenance of these tills utilizing a variety of methods, including bulk geochemistry from an XRF, grain size, organic carbon content, soil salt concentrations, and the uranium‐lead (U‐Pb) ages of detrital zircon sands contained in these tills. Preliminary results from Arena Valley, Vernier Valley, Lower Wright Valley, and the Royal Society Range indicate that grain size does not change with age of the till or source area. Organic carbon increases in older tills, but soil mixing and erosion of surfaces may impact this trend. The Chemical Index of Alteration (CIA) generally increases with till age, but overall values are low showing little weathering by hydrolysis in this area. Common geochemical markers used to distinguish provenance like Ba-Zr and Nb-Y, do not show much distinction between source areas, but Sr-Rb appears useful for characterizing provenance. We are separating detrital zircon from each unit to determine the zircon U-Pb age distribution of each till, which we hope will deepen the provenance information.

1106

Unraveling the Antarctic Krill microbiome present in Krill internal and external body parts

M.S. Alicia Prior^1,2, Dr. Juan Höfer^3,4, Dr. Camila Fernández^5,6,7, Dr. Asunción de los Ríos¹, Dr. Jesse McNichol^8,9, Dr. Jed Fuhrman⁹, Dr. Ramiro Logares¹⁰, Dr. Bjorn A. Krafft¹¹, Dr. Mireia Mestre^1,4,5

¹National Museum of Natural Sciences (MNCN-CSIC), Madrid, Spain. ²Universidad Autónoma de Madrid (UAM), Madrid, Spain. ³Pontifical Catholic University of Valparaíso (PUCV), Valparaíso, Chile. ⁴IDEAL Center, Austral University from Chile (UACh), Valdivia, Chile. ⁵COPAS-Coastal Center, University of Concepción (UdeC), Concepción, Chile. ⁶University of Concepción (UdeC), Concepción, Chile. ⁷Laboratory of Microbial Oceanography, CNRS UMR7621, Banyuls sur Mer, Chile. ⁸Saint Francis Xavier University (StFX), Antigonish, Canada. ⁹University of Southern California (USC), Los Ángeles, USA. ¹⁰Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain. ¹¹Institute of Marine Research (IMR), Bergen, Norway

Abstract

The Antarctic krill (Euphausia superba) biomass is estimated between 300 and 500 million tons. Because of its large biomass and central position in the marine food web, krill is considered a key species that shapes the functional diversity, productivity, and carbon sequestration of the Southern Ocean. Krill populations are declining while salps abundances are increasing, potentially altering Southern Ocean food webs and future carbon sequestration. This study analyzes the krill microbiome obtained from 70 individuals, in different body parts (exoskeleton, molt, stomach, hepatopancreas and fecal pellets), and in two distant geographical locations (South Orkney and South Georgia Islands). Diversity analyses revealed that the number and composition of species were different among krill body parts and geographical locations. Yet, certain taxa predominate in almost all samples: the prokaryotic Class Gammaproteobacteria, and the eukaryotic Classes Gregarinomorphea and Phyllopharyngea. We also observed that microbial communities changed gradually between geographic locations and between biologically related body parts (i.e., between exoskeleton and molt, and between different parts of the digestive system). In each krill body part, we identified indicator species, that included both pathogenic (e.g., the prokaryotic Order Thiotrichales) and symbiont (e.g., the eukaryotic Order Eugregarinorida) microorganisms. Indeed, we found a major abundance of krill pathogens in the samples from South Georgia, the studied area with higher temperatures recorded in the water column. These findings reveal the importance of knowing more about the Antarctic krill microbiome and its links to Climate Change. In future steps, we will increase the number of samples (>500 samples) and the geographic range (>3 areas). The complete dataset (that will include metagenomes and the microbiome of salps and seawater) will allow us to describe the similarities and connections among krill and salps microbiomes, and also unveil their functionality.

1108

Ice cliff morphology of the tidewater glaciers in South Shetland Islands

Michal Petlicki

Jagiellonian University, Krakow, Poland. Universidad de Concepcion, Concepcion, Chile

Abstract

Ice calving is one of the important components of glacier mass budget and plays a crucial role in ice-ocean interaction. With ongoing climate change, many of the formerly tidewater glaciers of the Antarctic Peninsula region retreated and are in transition to land-based while retaining a limited contact with the ocean. This subtle changes are usually not resolved with sufficient detail with satellite remote sensing. To close this gap, a series of terrestrial lidar surveys were conducted at the termini of several outlet glaciers on Greenwich and King George Islands in the archipelago of South Shetlands. The obtained results show an interaction between the location of subglacial drainage outlets located at the high-water mark and the ice cliff morphology, with possible impacts on the mechanical stability of the cliff.

1109

Phototrophic eukaryotes dominate a relict marine assemblage supported by subglacial brine in the McMurdo Dry Valleys, Antarctica.

Dr Angela Zoumplis¹, Drishti Kaul¹, Dr Nick Schulte², Hong Zheng¹, Dr Pratap Venepally¹, Dr Jill Mikucki³, Dr Diane McKnight², Dr Andrew Allen^1,4

¹J. Craig Venter Institute, San Diego, USA. ²University of Colorado Boulder, Boulder, USA. ³University of Tennessee, Knoxville, Knoxville, USA. ⁴Scripps Institution of Oceanography, San Diego, USA

Abstract

The McMurdo Dry valleys (MDVs) region of Antarctica is highly sensitive to climate warming, with microbial communities undergoing rapid, lasing compositional shifts in response to temperature and hydrological disturbance which in turn can produce lasting changes in microbial community structure. Geochemical evidence suggests past warm intervals produced a rise in sea level that contributed to substantial flooding within the MDVs. Waters from these floods would have persisted for millions of years before retreating, leaving behind salts with the potential to maintain marine assemblages. We assessed the MDVs for evidence of microbial remnants of marine incursions. A survey of molecular diversity was conducted with over 160 aquatic, sediment and aeolian samples collected across freshwater, marine and terrestrial habitats around Victoria Land, Antarctica. Results of this survey reveal a previously unknown, dominant, marine eukaryotic community surrounding the Blood Falls area of the Taylor Glacier terminus (~30 km inland of the McMurdo Sound). Marine indicator species were identified across several phylogenetic groups including diatoms, haptophytes, dinoflagellates and ciliates in red hued ice, mud and sediment samples associated with discharge near Blood Falls. Metatranscriptomics analyses on the Blood Falls community depicts an active, metabolizing community with upregulated functions in cell motility, signaling, stress resistance and morphological transformation. These findings shed light on the mechanisms of microbiota survivability and suitability in osmotically variable habitats.

1113

Isolation and Characterization of Antarctic Coronavirus with Potential Impact on the Poultry Industry

Camila Soto¹, Camila Ortega¹, Dra. Catalina Pardo^2,3, Dr. Leonardo Almonacid^2,3, Dr. Gonzalo Barriga¹

¹Universidad de Chile, Department of Virology, Emerging Viruses Laboratory, Faculty of Medicine, Santiago, Chile. ²Pontificia Universidad Católica de Chile, Department of Pediatric Infectious Diseases and Immunology, School of Medicine, Faculty of Medicine, Santiago, Chile. ³Pontificia Universidad Católica de Chile, Department of Child and Adolescent Health, School of Nursing, Faculty of Medicine, Santiago, Chile

Abstract

The Antarctic continent is known for being climatically extreme and home to a particular birdlife, among them, penguins of the genus pygoscelis. Its role, as a host or reservoir, for the viral pathogens identified in this area is still unknown. To date, there are only studies focused on massive sequencing techniques, but not their characterization. During 2022, we detected the presence of coronavirus from Pygoscelis papua chicks without signs of disease. We managed to isolate the virus in embryonated chicken egg system, where we identified multiple alterations, suggesting its potential impact on this specie, reinforcing the importance of monitoring the presence of emerging viruses in extreme climates, in order to prevent the industry from poultry at national level. To do this, infections were carried out on 9-day-old embryos with different viral loads of the isolated coronavirus, revealing its high pathogenicity, since embryonic mortality reached 80%. The necropsy showed mild lesions, growth retardation in more than half of the embryos, and even lesions so severe that they did not allow a reliable measurement. Subsequently, the virus was subjected to temperatures between -80ºC and 56ºC to evaluate the resistance to this variable and the integrity of the viral particle, however, the results obtained indicated that it is not a relevant factor during the infectious process. Finally, partial sequencing of the isolated virus was performed using Nanopore, presenting a similarity of 90% with the only described sequence of an avian Deltacoronavirus detected in an Antarctic penguin tick virome. This is the first characterization of an Antarctic Deltacoronavirus, and its resistance to extreme temperatures due to its evolutionary adaptation according to its host, reinforces the importance of viral surveillance in isolated places such as Chilean Antarctica.

1115

Perspective on South Africa’s role in science and research by analysing material collected by the Antarctic Legacy of South Africa

ms Maria Olivier

Stellenbosch University, Stellenbosch, South Africa. Antarctic Legacy of South Africa, Stellenbosch, South Africa

Abstract

As a digital archivist I collect many materials from South Africans that have been involved in the Antarctic region and Southern Ocean. This material that covers the history of South Africa’s involvement reveal important insights on the relationship of science and research done by South Africans.

Diaries, description of images, letters, journal articles and documents are a huge source of information. Since 2009 material has been collected for the digital archive. Digital archiving of material for the Antarctic Legacy of South Africa repository has a lot to do with correct metadata and assessment and evaluation of material and need for understanding South African involvement in the Antarctic region is of utmost importance. Especially in the South Africa context ALSA has the responsibility to establish the correct date and history timeline of involvement. These factors led to in depth study of documentation and images to create a timeline since before the heroic age. The timeline started from a low impact for an exhibition and pan out to be part of the digital museum, posters for established museums, public lectures to specific groups. Initially these timelines focussed on the bases and the vessels. Since 2020 a renewed interest in South Africa’s participation and collaboration in research has come forward. As archivist I have worked through documents already available on the archive to establish the timeline of research within the Antarctic region. In this presentation I shall highlight these timelines and how events in the world and South Africa had an influence on these timelines. This research timeline may lead to more research within the social sciences and humanities.

1116

Periodic reorganization of landscapes in the coastal plain of extreme southern Brazil and its correlation with Antarctic temperature curves during the Holocene

PhD Veridiana Ribeiro¹, PhD Jefferson Cardia Simões¹, PhD Margot Guerra Sommer², PhD Rualdo Menegat², PhD Lidia Aumond Kuhn³

¹Centro Polar e Climático of the Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ³Universidade Federal do Paraná, Curitiba, Brazil

Abstract

Proxies analysis, including palynology, charcoal, and facies controlled by radiocarbon dating (¹⁴C) at three stratigraphic levels of a sedimentary core from the Águas Claras peatland (30º06'24.39” S; 50º49'04.90” W) identified different Climatic Moments (CM) correlatable to Marine Isotopic Stages 1 (MIS 1). CM 1 (7,329–7,165 cal years B.P.) indicates a marshy environment dominated by herbs, confirming evidence of a sudden decrease in temperature in the Southern Hemisphere after the Holocene thermal maximum, related to the decrease in temperature in Antarctica (-1.6ºC) and the glacial advance that occurred ~7,000 years B.P. CM 2, identified at the intermediate level (5,640–5,635 cal years B.P.), coincides with the maximum marine transgression in the costal plain of in Rio Grande do Sul State (CPRS) and identifies the beginning of peat deposition and a gradual increase in vegetation diversity, correlatable with the ascending temperature curve in Antarctica (-0.7°C about the Holocene mean). In CM 3 (1,590–1,515 cal years B.P.), the severe reduction in vegetation diversity in the peatland area, associated with evidence of a large fire detected by a charcoal peak, indicates the occurrence of drier environmental conditions and correlated with the temperature increase in Antarctica of +0.5°C. The changes detected in the different CMs show that coastal ecosystems responded sensitively to climate changes induced by temperature variations in the South Atlantic. These variations are connected with millennial climate changes recorded by the Antarctic temperature curve. The good correlation between CPRS CMs and variations in the Antarctic temperature curve suggests that these variations were also reflected in the South Atlantic in the studied Holocene interval.

1117

Humanitarian Missions of the Icebreaker Research Vessel Araon in Antarctic Sea: Lessons for Antarctic Travel and Global Cooperation

Eojin Yi*^1,2, Boram Koh², Myungshin Cho^2,3, Changsik Seo^2,4, Han Kyeom Kim^2,5

¹aSSIST University, Seoul, Korea, Republic of. ²Korean Society of Polar Medicine, Seoul, Korea, Republic of. ³Vincent Clinic, Seoul, Korea, Republic of. ⁴Q-line Woman's Clinic, Seoul, Korea, Republic of. ⁵Hanaro Medical Foundation, Seoul, Korea, Republic of

Abstract

We review the cases of the humanitarian rescue operations and related missions of the Icebreaker Research Vessel (IBRV) Araon in Antarctic Sea between 2011 and 2023. Highlighting its cooperative interventions during maritime emergencies, we extract valuable insights for improving Antarctic travel safety. The discussion extends to the implementation of advanced telemedicine, importance of faster satellite communication, effective quarantine strategies, and robust emergency response plans. These elements are crucial for enhancing the safety and resilience of Antarctic tourism, offering a blueprint for future polar travel and beyond.

1119

CO₂ fluxes at the Atlantic sector of the Southern Ocean

Dr Celina Cândida Ferreira Rodrigues^1,2, Dr Luciano Ponzi Pezzi¹, Dr Marcelo Freitas Santini¹, Dr Mylene Jaen Cabrera¹, Dr Luciana Shigihara Lima¹, B. Sc Tiffany Laura Januci Teles de Mendonça¹

¹National Institute for Space Research (INPE), São José dos Campos, Brazil. ²Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brazil

Abstract

The oceans play an important role in mitigating climate change by acting as a significant carbon sink, especially in high-latitude regions. The Southern Ocean (SO) has a significant impact on the global carbon dioxide (CO₂) budget. The main objective of this work is to investigate the CO₂ behavior under different environmental conditions in the Atlantic sector of the Southern Ocean. The in-situ CO₂ fluxes data were collected in the Drake Passage (DP) and the Bransfield Strait (BS) from 8 to 22 November 2018 and 3 to 22 November 2023. The CO₂ fluxes were obtained using the Eddy Covariance methodology. The synoptic atmospheric and oceanic conditions were obtained from satellite and reanalysis data sets. The analyzed variables were chlorophyll, sea surface salinity, sea surface temperature, air temperature, sea level pressure, and wind speed and direction. In November 2018, BS sank on average 38.59% more CO₂ than DP due to the colder water that intensified the CO₂ solubility in the ocean. The DP, on average, behaved as a CO₂ sink, mainly due to physical characteristics. Moreover, the climate modes of variability, such as El Niño-Southern Oscillation and Southern Annular Mode, and the proximity of a low atmospheric pressure system impacted CO₂ behavior. This study supports the hypothesis that ocean-atmosphere CO₂ fluxes depend highly on oceanic and atmospheric conditions. This study also contributes to an improved understanding of the importance of the SO in the global carbon balance.

1120

Antarctic plants in astrobiology: possible colonizers

Mrs. Dafne Anjos¹, MS. Rodrigo Barbosa¹, MS. Anna Donato¹, MS. Fabio Bones², Dr. Maithê Magalhães³, MS. Lucas Moreira³, Dr. Antônio Freitas¹, Dr. Cesar Amaral¹

¹Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. ²Universidade Federal de Santa Catarina, Santa Catarina, Brazil. ³Instituto Osvaldo Cruz, Rio de Janeiro, Brazil

Abstract

Antarctica provides a unique natural laboratory related to extreme environmental conditions, where some of the most resilient creatures of our planet can be found. These organisms have been largely studied in astrobiology context, involving survival in non-Earth conditions. Among these extremophile species, two antarctic plants emerge as good candidates to become colonizers of other planets and moons with life analogue conditions, such as Mars and Europa. Capable of resisting long time of water ressions, UV exposition and large range of temperature variations, the antarctic plants Sanionia uncinata and Colobanthus quitensis were selected for evaluation of growing under antarctic environmental conditions, on martian (MGS-1) and lunar (LMS-1) regolith simulators. In this field work, plants and Antarctic soil were sampled near the Wanda glacier during the austral summer of 2023, to design the experiment inside the Brazilian facilities on the Antarctic Peninsula. For 14 days we observed the survival responses of both species on martian simulator, lunar simulator and Antarctic soil collected in the sampling spots from Wanda. Results suggest that martian soil may be harsh for the plants, while lunar soil provides sufficient conditions to grow similarly to plants in the antarctic soil. Based on it, we discuss the importance and use of antarctic plants in astrobiology

1122

Diving physiology and behavior of crabeater seals (Lobodon carcinophaga) along the western Antarctic Peninsula

Anna Pearson¹, Dr. Luis Huckstadt², Dr. Joshua London³, Dr. Daniel Costa⁴, Dr. Michael Tift¹

¹University of North Carolina Wilmington, Wilmington, USA. ²University of Exeter, Penryn, United Kingdom. ³National Oceanic and Atmospheric Administration Fisheries, Juneau, USA. ⁴University of California Santa Cruz, Santa Cruz, USA

Abstract

Crabeater seals are generally considered to be shallow, short-duration divers with most of their dives occurring within 20 meters of the surface and at a duration less than two minutes during the austral summer. Variability in their diving behavior depends on the region, season, and environmental variables, as it is closely linked to the distribution of their preferred prey, the Antarctic krill (Euphasia superba). Here, we analyze data on diving behavior and aerobic capacity (calculated Aerobic Dive Limit, cADL) for adult (n=8, 6M, 2F) and subadult (n=6, 3M, 3F) crabeater seals along the western Antarctic peninsula in the austral winter of 2022 and 2023. The cADL was determined by estimating oxygen stores in the blood, muscle, and lungs. Crabeater seals were found to have hemoglobin concentrations of 20.5 ± 1.5 g dL^-1. Myoglobin concentrations were higher in adults (3.5 ± 0.6 g 100g^-1 muscle) than in subadults (2.7 ± 0.6 g 100g^-1 muscle) (p<0.05). The crabeater seals’ calculated aerobic dive limit was estimated to be 11 ± 1 minutes. Adult crabeater seals had a similar average time at depth (143 ± 80 m) to adult crabeater seals in the austral winter of 2001 and 2002 (92 ± 0.2 m) when krill distributions were found to be concentrated deep within the water column. Subadult crabeater seals did not dive as deep as adults, with an average time at depth of 72 ± 12 meters (p<0.05). This behavior suggests crabeater seals display seasonal foraging strategies and have the capacity for moderate dive depths and durations.

1123

OSTEOHISTOLOGY OF A PLESIOSAUR (SAUROPTERYGIA) FROM THE SNOW HILL ISLAND FORMATION (CAMPANIAN-MAASTRICHTIAN), JAMES ROSS ISLAND, ANTARTICA

Carolina Moraes, Dr. Arthur Brum, Dr Alexander Kellner, Dra Juliana Sayao

Antarctic Paleobiology and Paleogeography Laboratory, National Museum, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Plesiosauria is a clade of Mesozoic marine reptiles, which comprises four paddle pelagic forms. Due to its pelagic lifestyle, there are few ontogenetic series preserved in plesiosaurian fossil record. However, the paleohistology has been revealing valuable data on the ontogenetic trajectory and lifestyle of this group, even in isolated and fragmentary specimens. Here, we describe the microstructure of a plesiosaurian specimen from Santa Marta Cove (James Ross Island), where outcrops the rocks of Snow Hill Island Formation (late Campanian–early Maastrichtian; James Ross Basin). It comprises two vertebral centrum fragments—indeterminate axial region—, two rib fragments and three phalanges. The samples were measured with digital caliper. We cross-sectioned one dorsal rib to a paleohistological analysis, and the microstructure was observed under petrographic microscope. The specimen was assigned here as an indeterminate Plesiosauria due to the presence of an intersegmental artery foramen in one vertebral centrum. Compared with elasmosaurids—commonly found in the Upper Cretaceous of Antarctica—the specimen shares the ratio between height/breadth of phalanges ~1.4-1.6. This ratio is recovered as a dubious synapomorphy to Elasmosauridae. Nonetheless, we cautioned that this feature is widespread among Plesiosauria, including polycotylids (a group recorded to Santa Marta). Therefore, we limited our identification to Plesiosauria, due to the unpreserved diagnostic features. The cross-section displays a porous medullary cavity, with wide resorption cavities—osteoporotic bone. The cortex has wide erosional cavities and is mostly remodeled, with rare secondary osteons reaching a second generation. It indicates the begin of the bone remodeling. The secondary osteons have an irregular outline, characteristic to plesiosaurs. The periosteal region is marked by an external fundamental system. Such features indicate a slow-down bone deposition. These microstructural features suggest an adult stage. The osteoporotic bone is comparable with cetaceans, which indicates a pelagic swimmer plesiosaur.

1124

Southern peatlands of South America: geomorphological comparison, dating and C

Posgraduate student Lucas Barbosa, Dr. Jônatas Silva, Posgraduate student Heitor Palma, Posgraduate student Fernandes Pereira, Dr. Davi Gjorup, Dr. Márcio Francelino

Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

Peatlands of Southernmost America are non-renewable resources that provide important ecosystem services to the Patagonia region, but they are still poorly studied compared to the peatlands of the Northern Hemisphere. This study sought to compare the age of accumulation and carbon content in peatlands of different geomorphologies. Profiles were opened in two hydromorphic peatlands near the city of Ushuaia with altitudes ranging from 224 to 557m. The OM content was determined using the Walkey-Blakey method and the deepest horizons of each profile were dated using the ¹⁴C method. The first peatland is in a higher and more unstable position in the landscape in a periglacial environment. Its hydromorphism was favored by the site's concave microrelief. Its C content ranged from 336.2 to 595.2 g kg^-1 C. The organic material input came from the tundra-like vegetation mosaic. The base of the profile showed an estimated age of 1400 BP. The second peatland is in a more stabilized context in the landscape, at the bottom of the extensive glacial valleys that cut through the region. It showed greater accumulation compared to the aforementioned situation and the content ranged from 318.4 to 700 g kg^-1, with the carbon contribution probably coming from the extensive surface fields of Sphagnum, characteristic of the region. It had an estimated age of 2770 BP. Gaps in knowledge about the peatlands of the South are one of the obstacles to developing the rational and sustainable use of their non-renewable resources. The position of the peatland in the landscape may or may not favor the accumulation of carbon and result in different ages of C due to greater stability. The peatlands with the highest accumulations at the bottom of the valleys may suffer from anthropogenic influence, indicating a relevant issue for the development of conservation strategies in this ecosystem.

1127

ENVIRONMENTAL DNA AND METABARCODING AS A TOOL FOR THE ASSESSMENT OF MARINE BIODIVERSITY IN BAHÍA FILDES, THE ANTARCTIC PENINSULA

Valeria Prieto, Zambra López, Victoria Suescun, Luis Miguel Pardo, Leyla Cárdenas

Universidad Austral de Chile, Valdivia, Chile

Abstract

As a consequence of climate change, the temperature increase in the Antarctic Peninsula is becoming evident. This, along with the increase in maritime transport, which in turn leads to the possible introduction of non-native species, has an impact on marine ecosystems and their composition. To understand these effects on Antarctic biodiversity, it is necessary to have tools that allow for rapid and efficient monitoring assessments. Environmental DNA (eDNA) analysis along with metabarcoding techniques have been widely used in aquatic ecosystems to assess the overall composition of communities, as it allows for the detection of diverse groups of organisms from environmental samples. This study analyzes the marine biodiversity of metazoans using eDNA to evaluate the impact caused by different disturbances, both natural and anthropogenic, in Fildes Bay (62°05′S; 57°56′W), Antarctic Peninsula. For three summer seasons, seawater samples were taken at three different sites, an at different depths. One of the selected sites is affected by glacier melting, representing a natural disturbance. In contrast, another site is influenced by the presence of boats, constituting an anthropogenic disturbance. The third site is located between the two previously mentioned. A comparative spatial analysis on biodiversity detected bu eDNA was conducted between sites and a temporal analysis comparing the three summer seasons of the years 2022, 2023, and 2024. Additionally, a specific genetic database for Antarctic endemic organisms is being developed, with the aim of enriching the scarce genetic information that is still a limitation in molecular biodiversity studies.Tools such as eDNA and metabarcoding offer new advantages for biodiversity studies in isolated and extreme places such as Antarctica.

Funding and support: Fondap-Ideal 15150003, INACH MG-16-23

1128

Geoenvironments of Southern Tierra del Fuego: Morphology and chemistry of its soils.

Posgraduate student Lucas Barbosa, Graduate student João Paschoalino, Dr. Jônatas Silva, Posgraduate student Heitor Palma, Posgraduate student Fernandes Pereira, Dr. Davi Gjorup, Dr. Márcio Francelino

Universidade Federal de Viçosa, Viçosa, Brazil

Abstract

Geoenvironment is the geographical environment with a certain homogeneity of environmental factors of interest in a delimited territorial extension. The southern tip of Tierra del Fuego is characterised by very steep slopes and glacial valleys. In order to study the morphological and chemical characteristics of the soils, sampling points were chosen based on environmental stratification following geomorphological, pedological and vegetation indicators. Ten soil profiles in six different geoambients, located near the city of Ushuaia, were described and sampled. The altitude between the profiles varied from 25 to 829 metres. The soils collected were characterised chemically and physically. Metapelitic rocks of Cretaceous origin predominate in the study area. The periglacial geoenvironment has poorly developed, stony soils, low organic matter content, high base saturation and low CEC. Hydromorphic tundra geoenvironments give rise to differentiated and extremely organic soils. Drained tundras are morphologically compatible with the periglacial but accumulate more organic carbon. In forest geoenvironments, the presence of vegetation covers the ground and prevents the presence of snow. The closer they are to sea level, the more developed the soils are, with the formation of incipient B horizons, which are aluminous, yellowish in colour and deeper, with an accumulation of organic material in the more superficial layers. Peat bogs are very hydromorphic geoenvironments with extremely organic soils, with a high concentration of C and a dark colour, covered by cushions of Sphagnum spp. vegetation. The geoenvironment near Lake Fagnano in a Till deposit has less rainfall and soils made up of fragments of different granulometries, poorly developed pedogenetically and with less exuberant vegetation. The soils have physical and chemical similarities due to the homogeneity of the source material, but variations in altitude, relief, geomorphology and vegetation are the main factors that alter their morphology, highlighting the pedogenetic processes of paludisation, podzolisation and cryogenesis.

1129

Spatial variability of chlorophyll-a in the Bransfield Strait, Antarctica, during Austral summer of 2024

Luzmila Rodriguez¹, Victor Poma², Pablo Mendoza², Constanza Ricaurte³, Laura Martinez³, Cinthya Bello¹

¹Universidad Científica del Sur, Lima, Peru. ²Instituto Peruano de Energía Nuclear, Lima, Peru. ³Invemar, Santa Marta, Colombia

Abstract

Understand the spatial variation and vertical distribution patterns of phytoplankton (chlorophyll-a) in the Southern Ocean are important to identify the productive potential of the ocean as essential component of the global marine ecosystem. Despite their importance, the main sources and sinks that modulate the observed distributions of these organisms are poorly known in Antarctica, especially those associated with active hydrothermal volcanism in the depths of Bransfield Strait. The aim of this study was to investigate changes in the chlorophyll-a (Chl-a) concentration due to the contribution of iron derived from hydrothermal systems associated with volcanism at the bottom of the Bransfield Strait. Sampling and data collection procedures were conducted across the Central Basin of the Bransfield Strait, at Hook Ridge submarine volcanic edifice during the austral summer (February) 2024, on board the “BAP Carrasco”, as part of the XXX Peruvian Antarctic Expedition. Vertical profiles of temperature and salinity were taken with a SeaBird 911 plus-CTD sensor attached to a carrousel system bearing 5-L Niskin bottles for water sampling collected from 19 oceanographic stations to measure Chl-a and trace metals (Fe, Co and Cu) concentrations. Oxygen values were measured with a Seabird SBE 32 sensor. The Chl-a was analyzed at three depths and our preliminary results show that Chl-a concentrations ranged from 0.05 to 12 mg/m³.

1131

Spatial differences of precipitation regime, snow persistence and ground surface temperature through in situ measurements at Signy Island

Nicoletta Cannone^1,2, Francesco Malfasi^1,2, Stefano Ponti^1,2, Peter Convey³, Mauro Guglielmin^1,2

¹Insubria University, Varese, Italy. ²Climate Change Research Center, Como, Italy. ³British Antarctic Survey, Cambridge, United Kingdom

Abstract

Climate change has been strongly affecting Maritime Antarctica and is inducing significant acceleration in the responses of the abiotic and biotic components of terrestrial ecosystems. Despite a short and transitory cooling pulses, warming is among the most evident trend reported in the last decades, whereas snowfalls and precipitation patterns vary on regional and local spatial scales. The regime of precipitation is extremely important in many physical (i.e. ground surface temperature; active layer thickness), chemical (i.e. nutrient cycles) and biological processes of the ecosystems. However, because of the remoteness and climatic extremes few and sparse in situ measurements are available in the Antarctic continent so far.

Here, the aim is to describe the spatial and seasonal variability of precipitations and of snow persistence across Signy Island (South Orkneys) and its effect on the ground surface temperatures.

For these purpose, rain gauges were installed at different altitude on the two main slopes of the island along a West-East transect: Spindrift Cove (17 masl; West), Spindrift Col (108 masl, West), Jane Col (153 masl) and Backslope (108 masl, East). Air temperature, air humidity and wind speed were also available for Spindrift Cove and Jane Col. Snow persistence were assessed through monitoring the GST (-2 cm) in 18 sites located all over the island on elevations from 12 to 105 masl. All the data were automatically recorded on hourly or sub-hourly base with Onset and Decagon Devices loggers. The investigated period focused from January 2018 to May 2020.

From a preliminary analysis, the occurrence of an orographic effect on the regime of precipitation was confirmed on annualy and seasonal bases. Similarly, differences in snow persistence appear more affected by the aspect (West, East) rather than by the elevation variability, with some possible unexpected patterns on ground surface temperature.

1133

A one-century overview of organic matter inputs in sediments of a maritime Antarctica area based on bulk parameters and stable isotopes: insights of local environmental changes

Viviane K. Bisch¹, Satie Taniguchi², Marcia C. Bícego², Rafael A. Lourenço², Cesar C. Martins²

¹Federal University of Paraná, Pontal do Paraná, Brazil. ²University of São Paulo, São Paulo, Brazil

Abstract

The elemental composition and stable isotopes in the sedimentary organic matter (OM) are important geochemical tools for understanding environments, physical and biogeochemical processes, and even paleoclimatic conditions on Earth. Once the Antarctic Peninsula region is one of the few relatively preserved areas on the planet, sensitive to climate change, and yet remains the most unexplored continent, this study aimed to characterize the elemental and isotopic composition of marine sediments from different regions of Admiralty Bay, King George Island, Antarctica, to assess potential sources of OM. The sampling included: (i) Surficial samples sampled during the 2009–2019 period at three specific sites (one in Ezcurra inlet, another in Mackelar inlet, and the last one in Martel inlet), and; (ii) three sediment cores collected from each inlet of the bay in 2007-2008, covering at least the last five decades. A Thermo-Finnigan IRMS Delta V Plus elemental analyser was applied to determine stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes, total organic carbon (TOC), and total nitrogen (TN). OM in sediments from Ezcurra inlet primarily originates from terrestrial plants prevalent in Antarctica, such as mosses, lichens, and aquatic ones. Similarly, the Mackelar inlet is highlighted by significant contributions from these two abovementioned sources and algae. In contrast, Martel inlet exhibits diverse sources, predominantly influenced by various marine mammals and seabirds and their excrements, incorporating signals from mosses and lichens. However, recent sediments sampled post-2008 in Martel inlet show a decreased contribution of animal sources, and mosses and lichens emerging as the predominant sources corroborate patterns observed in the other inlets. The findings of this study provide unprecedented information about the input of OM to sediments in Admiralty Bay, indicating changes over the time scale studied.

1134

Antarctic Snow Microalgae: Adaptations to extreme environments, and the role of nutraceutical metabolites with biotechnological potential for Blue Economy approach in Aquaculture Industry.

Mr Claudio Rivas^1,2, Dra. Ana Farías², Msc. Alberto Augsburger¹, Dr. Renato Westermeier², Dr. Manuel Alarcón²

¹AlgaLife Biotech, Puerto Montt, Chile. ²Universidad Austral de Chile, Puerto Montt, Chile

Abstract

The threat of Global Climate Change presents a major challenge to humanity, threatening food systems around the world, with important questions about future food supply and human nutrition. Microalgae industry produce a wide range of metabolites for health, food and cosmetics, among others. Microalgae can contribute to decarbonization of wastewater treatment and atmospheric CO₂ sequestration. Commercial strains have been cultured on sites with high incident solar radiation, but in combination with high average temperatures as well. Thus, research exploring novel strains of microalgae with biotechnological potential and the ability to grow under low temperatures should be a relevant goal. Antarctic snow microalgae, Chloromonas reticulata, was isolated, identified and carried out a selective breeding process of domestication to improve growth, nutritional profile and robustness. Maximum (F_v/F_m) and effective quantum yields of fluorescence of PSII, as well as growth rates, were measured in algae grown at 1ºC, 14ºC and 24ºC with and without nutrient limitation. PSII photochemical yield was unaffected by temperature, present values higher than 0.64, this means, a healthy microalgal culture. The specific growth rate (in the exponential phase), decreases with increasing temperature, from 0.19 day^-1 at 1ºC to 0.12 day^-1 at 24ºC. Protein contents were high (> 40% of dry weight) in all treatments. The fatty acid profile was characterized by a high proportion of PUFAs (> 55% of total fatty acids), especially omega 3. Carotenoids (beta carotene, astaxanthin) increased the concentration 10-fold from 3 mg/g at 1ºC to 30 mg/g at 24ºC when nitrogen is limiting. Results suggest this strain as promising candidates for aquaculture diversification in colder countries, since it produces compounds of high commercial and nutritional value in a wide temperature range.

Funding: Inach project DT_09-14, ANID VIU19P0061 and FONDEF ID22I10333.

1135

Plant community responses to environmental factors across Antarctic islands: Insights from regional-scale analysis

Dra Daniela Schmitz¹, Dr Jair Putzke², Dr Pedro M. Villa³, Dr Antonio B. Pereira², Dra Flávia R. Ferrari^1,4, Dr Roberto F.M. Michel⁵, Dr Marcio R. Francelino¹, Dr Carlos Ernesto G.R. Schaefer¹

¹Núcleo TERRANTAR - Universidade Federal de Viçosa, Viçosa (MG), Brazil. ²Universidade Federal do Pampa, São Gabriel (RS), Brazil. ³Universidade Estadual Feira de Santana, Feira de Santana (BA), Brazil. ⁴University of Wollongong, Wollongong, Australia. ⁵Universidade Estadual de Santa Cruz, Ilhéus (BA), Brazil

Abstract

The ice-free areas of the Maritime Antarctica ecosystems are dominated by lichens and mosses and represent important ecological indicators of climate change. We aimed to comprehend how environmental factors influence the plant community structure at a regional scale. Our analysis focused on changes in species richness, composition, and vegetation cover across a pedoenvironmental gradient on Maritime Antarctic islands. We sampled 570 plots distributed across three distinct islands of the South Shetland Archipelago: Elephant, Half Moon, and Nelson Islands. Vegetation assessment was conducted through a phytosociological survey, evaluating the frequency, cover, richness, and composition of each species. Additionally, soil samples (0-10 cm depth) were collected for routine chemical analysis. The data were interpreted using descriptive statistics and principal component analysis (PCA). Overall, 76 plant species were recorded, including bryophytes (30 species: 27 mosses and two liverworts), lichens (42 species), and the two native Antarctic angiosperms. The most frequent and abundant species were the mosses Sanionia georgicouncinata and S. uncinata. Despite lichens exhibiting greater species richness, mosses constituted 86% of vegetation cover. Half Moon exhibited the highest species richness with 50 species, followed by Nelson Island (45 species), and Elephant Island (35 species). Species composition significantly varied among the islands, with only 14 species being shared. The results revealed substantial variability in soil characteristics, with PCA explaining 53.6% of the variation of soil properties across the three islands. Half Moon Island exhibited the highest averages of organic matter and phosphorus. Factors such as exposure time, well-developed soils with significant past ornithogenic influence, and environmental heterogeneity may have contributed to greater plant diversity on Half Moon Island. Identifying and monitoring the factors shaping vegetation distribution is crucial for comprehending its response to climate change.

1138

A continental trace fossil suite in the López de Bertodano Formation, SandwichBluff Member (Vega Island)

Dr Daniel Sedorko¹, Dr Luiz Carlos Weinschutz², Dra Juliana Sayao³, Dr Alexander Kellner⁴

¹Paleoinvertebrate Sector, Department of Geology and Paleontology, National Museum, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ²Centro de Pesquisa Paleontológica, Universidade do Contestado, Mafra, Brazil. ³Antarctic Paleobiology and Paleogeography Laboratory, National Museum, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. ⁴Antarctic Paleobiology and Paleogeography Laboratory, Department of Geology and Paleontology ,National Museum, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

The López de Bertodano Formation at Vega Island presents an important record of paleovertebrates, such as crown birds, non-avian and avian dinosaur remains, and the unique hadrosaur from Antarctica. Marine fossils also occur in this unit, including Chondrichthyes and Plesiosauria, as well as cephalopods and bivalves. The trace fossils from the Sandwich Bluff Member have been known only by mention in papers dealing with paleovertebrates, paleopalynology, or dating. The ichnogenera Thalassinoides, Ophiomorpha, Planolites, and Teichichnus are the most recurrent mentions for this unit. Considering the facies signature, this member presents an upward increase in continental influence, evidenced by the transition from bioturbated siltstones to very fine-grained sandstones (mainly with Thalassinoides and Teichichnus) to sandstone levels rich in carbonized plant hash (locally with Palaeophycus and Thalassinoides). Although Ophiomorpha has been reported in this member at Vega Island, its existence is questionable due to the absence of photos and descriptions, and recent fieldwork did not confirm the presence of this ichnogenus. On the other hand, one horizon rich in a continental trace fossil suite was identified just below the probable contact with the basal Sobral Formation. This dense trace fossil suite is characterized by meniscated, sharp-walled burrows that are both vertically- and horizontally-oriented in relation to the bedding plane, and they are identified here as Beaconites. Previous studies have mentioned a Thalassinoides level close to the top of the Sandwich Bluff Member marking a sequence boundary, which occurs almost 50 cm above this Beaconites level. The K-Pg boundary has also been placed in this interval, based on U-Pb zircon

1139

Exploring microbial diversity and biogeography across snow-covered regions

Jéssica Bianca da Silva, Valeria Maia Oliveira

Campinas University, Campinas, Brazil

Abstract

Snow-covered landscapes are widely distributed across various regions of our planet, including high-altitude mountain ranges and temperate regions during the winter season, such as the Arctic tundra, boreal forests, and alpine ecosystems, as well as in the vast polar expanses of Antarctica and sub-Antarctic islands. Seasonal snow regulates global climate patterns and impacts local climates and ecosystems significantly. Through governing freeze-thaw events, snow extent, and coverage profoundly affect soil microbial community composition and mediate biogeochemical cycles. Despite the apparent hostility of snow ecosystems, as low temperatures and atmospheric humidity, limited liquid water availability, and high radiation levels, they harbor diverse and active microbial communities that can be endemic or transported from distant locations. Through the atmospheric deposition of non-indigenous microorganisms and particulate organic matter, snow serves as a dynamic reservoir of nutrients and microorganisms. However, studies on snow as an ecosystem are recent, and much of the microbial ecology of snow remains unexplored. This study investigated the diversity and biogeography of snow microbiomes in Antarctica, Alaska, Canada, China, Greenland, Iceland, Norway, and Switzerland. Using high-throughput sequencing analyses of the 16S rRNA gene of Antarctic microbiomes, and comparison with publicly available datasets from other cold regions across the globe, we assessed the taxonomic diversity distribution and the influence of geographical factors on snow microbial communities. Our results revealed different diversity patterns amongst the snow-covered areas, with Antarctica microbiomes compared to other snow-covered areas. Different genera were identified at each site, indicating that certain groups are differentially abundant and play relevant ecological roles in microbial communities. Polaromonas, Ferruginibacter, and Pseudomonas were the most abundant genera in most locations, especially in Antarctic regions. Geographic distance, seasonality, and climatic variables (latitude and wind) were shown to play a crucial role in differentiating microbial communities.

1147

Fine-scale modeling of humpback whales (Megaptera novaeangliae) in the western Antarctic Peninsula using an Integrated Nested Laplace Approximation approach

PhD Karina do Amaral^1,2, PhD Dalia C. Barragán-Barrera^3,4,5,6,7, María Paula Rey-Baquero⁴, Sandra Bessudo^5,7, Andrea Bonilla-Garzón^7,8, PhD Natalia Botero-Acosta⁹, PhD Susana Caballero^7,10, Dalila Caicedo¹¹, Juan Capella¹², María Claudia Diazgranados^7,13, Lilían Flórez-González^7,12, Diego F. Mojica-Moncada^3,5,7, Federico Riet-Sapriza¹⁴, Fernando Trujillo^7,11, Adrián Vásquez-Ávila¹¹

¹Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ²Plazi, Porto Alegre, Brazil. ³Association of Polar Early Career Scientists of Colombia (APECS Colombia), Bogotá, Colombia. ⁴Instituto Javeriano del Agua, Pontificia Universidad Javeriana, Bogotá, Colombia. ⁵Fundación Malpelo Y Otros Ecosistemas Marinos, Bogotá, Colombia. ⁶R&E Ocean Community Conservation, Oakville, Canada. ⁷Programa Antártico Colombiano, Comisión Colombiana del Océano, Bogotá, Colombia. ⁸The Cornell Lab, Cornell University, New York, USA. ⁹Fundación Macuáticos Colombia, Medellín, Colombia. ¹⁰Laboratorio de Ecología Molecular de Vertebrados Acuáticos (LEMVA), Departamento de Ciencias Biológicas, Universidad de Los Andes, Bogotá, Colombia. ¹¹Fundación Omacha, Bogotá, Colombia. ¹²Fundación Yubarta, Cali, Colombia. ¹³Conservación Internacional Colombia, Bogotá, Colombia. ¹⁴Vida Silvestre, Montevideo, Uruguay

Abstract

A fundamental step for the species conservation is knowing about its geographic range at a fine-spatial scale, particularly for species that depend on polar habitats for feeding and/or breeding, since these habitats are affected by climate change. Opportunistic data of Humpback whales (Megaptera novaeangliae) obtained from expeditions to western Antarctica Peninsula (wAP) may be important to improve the knowledge on how this species will deal with climate change, since wAP is a whales’ feeding ground and the highest temperatures in Antarctica has been reported there. However, opportunistic data may have some issues in commonly applied techniques used for modeling species-distribution. Therefore, we aim to model the distribution of Humpback whales in the wAP using a relatively new model-fitting approach: the Integrated Nested Laplace Approximation (INLA) based on Hierarchical Bayesian Modeling. We used data from the Marine Mammal Monitoring Program at the Colombian Antarctic Program, which has conducted surveys to assess occurrence patterns of marine mammal species along the Southeastern Pacific Ocean and the Southern Ocean, following a transect from Panama to the wAP. Around 350 sightings of Humpbacks whales collected on four expeditions from 2014-2015 to 2018-2019 during austral summers were used. Sea-surface temperature, productivity, topographic, and sea-ice related layers were collected from public databases, mainly Copernicus and GEBCO. We used a workflow to run models in continuous space using a Log-Gaussian Cox Process (LGCP). All functions are implemented in the inlabru interface available in the R-INLA package for R. Despite we’re in a very initial step of our modeling, testing the spatial and temporal resolution that will provide better results, we expect that the final output of our models will be much more accurate than traditional modeling, providing important insights on how Humpbacks are using their habitat around wAP in the last few years at fine-spatial scale.

1148

Elemental and isotopic characterization of sedimentary organic matter of Collins Bay, King George Island, Antarctica

Victória Hillesheim Garcia e Silva¹, Viviane K. Bisch¹, Jamile Tamer Nasser², Marcia C. Bicego², Natalia Venturini³, Cesar C. Martins²

¹Federal University of Paraná, Pontal do Paraná, Brazil. ²University of São Paulo, São Paulo, Brazil. ³Universidad de la Republica, Montevideo, Uruguay

Abstract

The Antarctic continent is a unique environment far from human activity, making this region an important area to understand the Earth's ecological changes, under conditions of minimal anthropogenic interference. We investigated the processes involving organic matter (OM) and their sources and composition in the seabed sediment. Sedimentary OM is an important source of nutrients for biological communities in marine environments, and its quality and quantity are influenced by temperature, pH, dissolved oxygen, salinity, biogeochemical processes, sedimentation rate, and others. Marine sediments (surface layer: 0-2 cm) were sampled along the sediment deposition margins of Collins Bay, located in Maxwell Bay, King George Island, Antarctica. This bay hosts the Uruguayan Artigas Antarctic station on the west bank. The sedimentary OM parameters analysed were: total organic carbon (TOC), total nitrogen (TN), ratio between TOC and TN (C/N ratio) and the carbon (𝛅¹³C) and nitrogen (𝛅¹⁵N) isotopic ratios. The TOC varied between 0.50 and 1.28%, while TN presented values in a range of 0.10 to 0.18%. The sites with the lowest values of TOC and TN are located close to the coast. The C/N ratio presented all results between 5.80 and 8.64, that suggests sedimentary OM from marine animal excrement. The 𝛅¹³C varied from -25.75 and -24.61‰, indicating that sedimentary OM may have its origin in sources such as Antarctic phyto- and, zooplankton species, mosses, lichens, or even ‘fresh’ feces from marine animals. This 𝛅¹³C values showed that sites close to the coast were more enriched in the ¹³C isotope, while sites in the central sector of the bay presented values less enriched. The 𝛅¹⁵N ratio varied from -1.75 to 2.88‰, which may be related to the OM from planktonic community species and penguin excrement. These results may contribute to understand changes in sedimentary OM in a scenario of climate change and global warming.

1150

Mapping Diversity: A Profile Analysis of Brazilian Polar Early Career Scientists

Raphael Fernandes Vieira¹, Dr. Maria Jimena Cruz², M.Sc. Hugo Alves Mariz de Moraes³, Dr. Graciéle Alves de Menezes⁴, Dr Gustavo Souza dos Santos⁵, Dr Joseline Manfroi⁶, Dr. Paola Barros Delben⁷

¹Universidad Nacional de la Plata (UNLP-Argentina), La Plata, Argentina. ²Multidisciplinary Institute of History and Human Sciences (IMHICIHU, Argentina), Buenos Aires, Argentina. ³Universidade Federal de Pernambuco (UFPE, Brazil), Recife, Brazil. ⁴Universidade Federal de Minas Gerais (UFMG, Brazil), Belo Horizonte, Brazil. ⁵Universidade do Estado da Bahia (Brazil), Salvador, Brazil. ⁶Instituto Antártico Chileno (INACH, Chile), Santiago, Chile. ⁷Universidade Federal de Santa Catarina (UFSC, Brazil), Florianopolis, Brazil

Abstract

During the second half of 2023, the Brazilian National Committee of the Association of Polar Early Career Scientists (APECS-Brazil), conducted a survey among its members, to better understand their realities, challenges, and goals. Inquiries about their academic formation and current professional status, as well as questions related to their ethnicity; gender; sexual orientation; place of residence; experience living, studying and/or working abroad; experience with fieldwork in polar, oceanic, and mountainous environments; were made. APECS-Brazil sought to track down the profiles of each of its members, not only to know them better, but also to bring them closer and shape its activities and projects to attend their aspirations and expectations, helping them to be better polar early career scientists. Another purpose of this survey, and the most interesting to this work, it is the comparison between the profiles of members of Brazilian National Committee and the database of the last census carried out in Brazil, in 2022, by Instituto Brasileiro de Geografia e Estatística (IBGE – Brazilian Institute of Geography and Statistics), a public institute of the Ministry of Economy, responsible for collect geographic and statistical information, among others, all over the country. The aim in crossing those data is to find out how close – or how far – are the APECS-Brazil members of the reality of their country, and to know what needs to be done to improve its representativity and which are the most sensitive points to close the gap amid its membership and the Brazilian society.

1153

Edisto Inlet fjord provides an ultra-high resolution Holocene paleoclimatic record for recontructing the evolution of the northern Victoria Land's glaciers.

Francesca Battaglia¹, Luca Baradello², Ester Colizza³, Michele Rebesco², Vedrana Kovacevic², Manuel Bensi², Laura Ursella², Daniela Accettella², Danilo Morelli⁴, Nicola Corradi⁴, Florence Colleoni², Naomi Krauzig⁵, Pierpaolo Falco⁵, Andrea Caburlotto², Emiliano Gordini², Leonardo Langone¹, Laura De Santis²

¹Institute of Polar Sciences ISP-CNR, Bologna, Italy. ²National Institute of Oceanography and Applied Geophysics—OGS, Trieste, Italy. ³University di Trieste, Department of Mathematics, Informatics and Geosciences, Trieste, Italy. ⁴University of Genoa, Department of Earth, Environment and Life Sciences - DISTAV, Genova, Italy. ⁵Marche Polytechnic University, Ancona, Italy

Abstract

Current knowledge of processes driving Antarctic ice outlets response to past climate is still poor, although it is needed to understand the evolution of the ice sheet and predict its contribution to sea level rise. This work provides new insights about the depositional environment of coastal glacial systems, draining from EAIS outlets in the North Victoria Land.

Bathymetry and high-resolution reflection seismic data, combined with sediment core records and oceanographic measurements in the Edisto Inlet Fjord document that the post-LGM sedimentation has been influenced by deposition of glacimarine deposit lately covered by biogenic (mainly diatom ooze) material, locally redistributed by bottom water currents. The interplay of pelagic sediment settling and of reworking by persistent and slow circulation resulted in the formation of confined sediment drifts-moat features. A Holocene sediment section up to 130 meters thick has accumulated in the central part of the fjord.

Our results highlight the potential of this region for future drilling, to provide an unprecedented record for reconstructing the evolution of northern Victoria Land's glaciers in relationship with climate and the Ocean circulation changes.

1154

IN-SILICO AND EXPERIMENTAL SEARCH FOR INTEGRATIVE AND CONJUGATIVE ELEMENTS OF THE SXT/R391 TYPE 1 FAMILY IN ANTARCTICA

Daniela Pirajan¹, Lucas Martínez Álvarez^2,3,4, Walter Mac Cormack^2,5, Graciana Willis-Poratti^2,3, Vázquez Susana^5,4, Cecilia Quiroga^1,6

¹Institute for Research in Microbiology and Medical Parasitology (UBA-CONICET), Buenos Aires, Argentina. ²Argentine Antarctic Institute, San Martín, Argentina. ³National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina. ⁴Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina. ⁵Institute of Nanobiotechnology NANOBIOTEC (UBA-CONICET), Buenos Aires, Argentina. ⁶Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina

Abstract

Integrative and Conjugative Elements (ICEs) of the SXT/R391 family participate in the transfer of genetic material between bacteria, contributing to gene dissemination and bacterial survival. Their structure contains 52 conserved core genes distributed in 7 different modules, interrupted by genes that may encode for metal or antimicrobial resistance, mobile genetic elements, defense systems, etc. These elements have been identified mainly in clinical isolates, but previous analyzes showed an increased incidence in aquatic niches. The aim of this work was to evaluate the distribution of ICEs SXT/R391 among Antarctic ecosystems. We screened for ICEs SXT/R391 in 53 bacterial isolates and 12 culturable bacterial communities recovered from different sites around Carlini Station, King George Island (Potter Cove water, rocks, and sediments, intertidal biofilms, sand, macroalgae, fish, lagoon freshwater and sediments, soil) by PCR targeting specific gene markers (setC and traV). We did not obtain positive results, although correct DNA extraction was confirmed by 16S rDNA amplification. Therefore, we looked for ICE SXT/R391 on metagenomes from Antarctica available at the JGI database. The selection criteria were defined using keywords “environmental”, “Antarctica”, “aquatic”, resulting in a dataset of 1005 metagenomes. IntSXT, SetC and TraV sequences were used as queries (ID cut-off >95%). We obtained two hits from fumarole sediment metagenomes recovered from Deception Island. We verified the presence of ICE SXT/R391 using additional amino acid sequences (UmuC, TraN, TraG and Bet), which showed at least 3 hits for each sample. Last, we evaluated individual scaffolds (12) to detect and analyze the respective genetic surroundings, which revealed that all sequences had ID 96-100% at the nucleotide level and the typical architecture. Our results confirm that the ICEs from the family SXT/R391 are circulating among Antarctic microbial communities and may contribute to gene flux and bacterial genome evolution.

1156

ANTCAT – New Zealand’s Antarctic metadata catalogue

Mr Mike Meredyth Young^1,2, Prof Jordy Hendrikx^1,2, Prof Nancy Bertler^2,3,4, Prof Ian Hawes^2,5

¹Antarctica New Zealand, Christchurch, New Zealand. ²New Zealand Antarctic Science Platform, Christchurch, New Zealand. ³GNS Science, Wellington, New Zealand. ⁴Victoria University of Wellington, Wellington, New Zealand. ⁵University of Waikato, Tauranga, New Zealand

Abstract

The Antarctic Science Platform (https://www.antarcticscienceplatform.org.nz/) in collaboration with Antarctica New Zealand launched a new data sharing initiative in 2023 - the New Zealand Antarctica Metadata Catalogue (AntCat - https://antcat.antarcticanz.govt.nz). AntCat centralises New Zealand’s Antarctic and Southern Ocean data, including observed parameters (physical, chemical, biological), obtained with a range of platforms (ships, moorings) and instruments (tide gauges, automatic weather stations). The catalogue now hosts over 100 distinct data records and provides significant advancements in data sharing capability.

AntCat operates by indexing 3^rd party repositories, it does not currently host data. Data are described with ISO19115-3 compliant metadata, and implement Global Change Master Directory (GCMD) keywords for naming science types, parameters, platforms, locations, and projects. AntCat data resources are made available across several application programming interface (API) endpoints providing data dissemination at national and international levels.

AntCat has been extended to output Schema.org dataset metadata providing integration with Polar Federated Search and Google Datasets. Our Schema.org profile has been extended to include a “DataLink” attribute which provides a direct link to the data file(s) download URL. This provides advanced cloud service (Oceanum Datamesh - https://oceanum.io) integration for interacting with environmental data beyond our collection.

A case study example of AntCat utility is provided by the recent incorporation of a long-term atmospheric collection (1982 – Present). These data are represented by eight metadata records, consisting of over 30 gas species, across four different 3^rd party repositories. While the curation level of these data are without URL accessible data - failing to satisfy Datamesh integration, AntCat incorporates all data types and accepts that achieving the highest levels of curation is an iterative process undertaken in cooperation with researchers.

This presentation will describe the structure of AntCat, discuss challenges with its set up and implementation, and provide recommendations for those seeking to develop similar repositories.

1157

Potential Impact of Climate Change on Antarctic Krill Carbon Sequestration Capacity by 2100

Yanara Morgunovsky-Avendaño¹, Dr Andrea Piñones^1,2,3,4, Dr Ricardo Giesecke^1,2

Abstract

Antartic krill (Euphasia Superba) plays a crucial role in Antarctic ecosystem, as it maintains the nutrient cycle, the trophic food web and acts as a carbon sink, efficiently mitigating global warming. This study examines how climate change may impact Antarctic krill and its carbon sink capacity by the year 2100. Circumpolar biomass data and empirical estimates of ingestion, egestion and sinking rates of particulate organic carbon (POC) were used to estimate present day sedimentation rates. Afterward, using POC simulations obtained from the 5.8.5 scenario of the Coupled Model Intercomparison Project Phase 6 (CMIP6), end of the century sedimentation rates were estimated and rates of change by 2100 were obtained at a circumpolar scale. The results suggest that by 2100 carbon flux through krill will be higher in regions like East Antarctica but there will be a significant reduction in regions like the Scotia-Weddell confluence, where Antarctic krill populations are higher. This underscores the importance of krill in regulating the carbon cycle. The study highlights the significance of recognizing Antarctic organisms in climate change mitigation strategies also shows the urgency of conserving the Antarctic ecosystem.

1161

Paleoenvironmental and paleoclimatic assessment of Seymour Island deposits, Antarctica: insights on the Cretaceous–Paleogene transition based on palynomorph analysis

Luiza da Silva¹, Alessandra Santos², Gerson Fauth², Leslie Manríquez³, Karlos Kochhann², Rodrigo Guerra^2,4, Rodrigo Horodyski^2,5,6

¹Universidade do Vale do Rio dos Sinos (Unisinos), São Leopoldo, Brazil. ²Instituto Tecnológico de Paleoceanografia e Mudanças Climáticas (itt Oceaneon, Unisinos), São Leopoldo, Brazil. ³Laboratorio de Paleobiologia de Antártica y Patagonia, Instituto Antártico Chileno - INACH, Punta Arenas, Chile. ⁴Museu Itinerante de Ciências Naturais, Carlos Barbosa, Brazil. ⁵Programa de Pós-Graduação em Geologia, Universidade do Vale do Rio dos Sinos (Unisinos), São Leopoldo, Brazil. ⁶Museu de História Geológica do Rio Grande do Sul (Unisinos), São Leopoldo, Brazil

Abstract

Studying past-living organisms is an important task for understanding Earth climate behavior, especially at high-latitudes. This study is based on palynological analysis of 35 slides from the Filo Negro Section (Seymour Island), aiming to describe paleoenvironmental changes occurred around the Cretaceous–Paleogene (K–Pg) transition. For this, P/G (peridinioid/gonyaulacoid dinoflagellate cysts) and T/M (terrestrial/marine palynomorphs) ratios, as well as percentage variation analysis of specific palynological groups, were adopted for paleoproductivity and paleoenvironmental inferences. The χ² and Mann Kendall Trend tests and dominance (Simpson)/diversity (Shannon-Wienner) indices were also applied to palynomorph counts. Statistical analyses are coeval with the P/G ratio, and diversity index is in agreement with some observed palynological events. Paleoclimates were relatively warm and humid by the end of Maastrichtian, shifting to less warm conditions and gradually lower temperatures during the K–Pg transition. The beginning of Danian would have cold/temperate climates and intermediate humidity conditions. Our data suggests higher paleoproductivity during the upper Maastrichtian, dropping before the K–Pg and remaining relatively low in the beginning of the Danian. With dinoflagellate cyst (dinocyst) percentages variation analysis, a significative increase of gonyaulacoid dinocysts (autotrophic) at the expense of peridinioid dinocysts (generally known for their heterotrophic origin) is detected after the Maastrichtian. However, several studies indicate that the meteor impact at Chicxulub (~66 Ma) would have ejected large soot concentrations into the atmosphere, promoting a long period of darkness on Earth (limited sunlight entrance). In this scenario, autotrophic organisms would have been highly affected. Nevertheless, in this study, a considerable increase of autotrophic organisms is detected during and after the K–Pg. Based on this, we propose the possibility that the studied region and possibly other parts of Antarctica were not severely affected by reduction of sunlight entrance into the atmosphere. [PROANTAR: 442676/2018-2]

1162

A record cold (− 69.1° C) event in the McMurdo Dry Valleys.

Peter Doran¹, Krista Myers¹, Chris McKay², David Bromwich³

¹Louisiana State University, BATON ROUGE, USA. ²NASA Ames, Moffett Field, USA. ³the Ohio State University, Columbus, USA

Abstract

In 1993, NSF funded the McMurdo Long Term Ecological Research (MCM LTER) site, which built a meteorological network which included a station on the shore of Lake Vida in Victoria Valley installed in 1995. This presentation describes conditions surrounding the lowest temperature ever recorded in the McMurdo Dry Valleys at Lake Vida and compares them to other nearby meteorological stations (Campbell Scientic CR10x’s). During a long calm period on 14 July 2018 at 01:00 local time, the Lake Vida (LVi) 3 m temperature sensor measured a record low temperature for the entire McMurdo Dry Valley meteorological data set of -69.1^oC. The extreme minimum temperature observed was 22^oC below the average temperature for this day, which is three standard deviations lower than the mean. The LVi meteorological station has previously shown that Victoria Valley has similar summer temperatures to the other major valleys nearby, but winter temperatures are significantly lower. The low temperatures at LVi depend on both radiative and dynamical effects. During the winter the surface of the valleys cool by the emission of infrared radiation. When the sky is clear the downwelling infrared radiation from the atmosphere is small and the ground cools efficiently. The presence of water vapor and especially clouds increase the infrared opacity of the atmosphere reducing the efficiency of the surface cooling. Under windless conditions, surface cooling results in a stable layer of cold air at the valley bottom. Downslope winds disturb this stable layer of cold air. The record cold occurred during one of these windless periods.We conclude that a record cold at the LVi station in Victoria Valley occurred during a prolonged windless and dry period. The radiative cooling was terminated by an air mass moving into the region that carried more humidity and clouds and provided associated infrared warming.

1163

2D observation of the water column through seismic oceanography on the continental rise off the coast of George V Land (PNRA-COLLAPSE project)

Flavio Accaino, Giulia Matilde Ferrante, Vedrana Kovacevic, Laura Ursella, Manuel Bensi, Laura De Santis

OGS, Sgonico, Italy

Abstract

The Ocean in the continental rise off the George V Land margin is characterised by warm Circumpolar Deep Water interlayered between surface and bottom colder Antarctic waters. The integration of multichannel seismic profiles and oceanographic measurements, acquired by the Italian National Antarctic Programme (PNRA) project COLLAPSE, allows to image these water masses stratification in the region of their mixing.

Oceanographic dataset includes hull-mounted Acoustic Doppler Current Profiler data, thermosalinograph near-surface temperature and salinity measurements, and temperature profiles in depth obtained from Expendable BathyThermographs (XBTs). XBTs were deployed at intervals of ~10 km. Seismic data were acquired employing a 1500 m-long streamer, with intertrace of 12.5 m and distance between the shot points equal to 37.5 m.

Our analysis of the seismic data allows us to image coherent reflections in the water and estimate the sound velocity in the water column along the seismic lines. The correlation with the XBTs helps in understanding whether such seismic reflectors originate by changes in temperature, salinity and/or density. The integration between the oceanographic measurements, sparsely distributed in space and time, and the laterally continuous seismic data provide km-long snapshots of the water column and provides a piece of evidence of the water masses dynamics complexity of the region.

Here we present preliminary results showing fine-scale structures within and below the thermocline that may be related to eddies or internal waves. Below, the presence of sediment waves on the seabed would suggest an interaction between the water and seabed dynamics for a relatively long time in this region of the margin.

1164

Changes in body composition and physical activity levels of military personnel during an Antarctic summer and winter

Ms. Mateus Rumão¹, Ms. Nathalia Garcia², Ms. Lurdilene Pinheiro¹, Gabriel Benevenut³, Carlos Costa³, Dra. Michele M Moraes⁴, Dra. Rosa Arantes⁴, Dr. Thiago Mendes^1,2,5

¹Postgraduate Program in Science and Health, Universidade Federal do Maranhão, São Luis, Brazil. ²Postgraduate Program Physical Education, Universidade Federal do Maranhão, São Luis, Brazil. ³Marinha do Brasil, Rio de Janeiro, Brazil. ⁴Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ⁵Postgraduate Program in Medicine and Health, Universidade Federal da Bahia, Salvador, Brazil

Abstract

Antarctica has unique and challenging isolation, confinement and extreme environment (ICE) characteristics. Prolonged stay in ICE may require changes in lifestyle, diet and physical activity. Every year, soldiers spend the winter at Comandante Ferraz Brazilian Antarctic Station. Our objective was to compare body composition and physical activity of Brazilian military personnel between the summer and winter in Antarctica. Ten military personnel from the Brazilian Navy Group (2021-2022) (Ethics Committee protocol UFMG #19092819.8.0000.5149). Data collection was carried out in months of January (summer) and August (winter). To analyze body composition, total body mass, percentage of fat (%FAT) and muscle mass (%MM) were evaluated by a tetrapolar bioimpedance (BC601,Tanita,Japan). All tests were carried out in the early hours of the day, with volunteers fasting overnight and with an empty bladder before data collection. To analyze physical activity, a wristwatch (ActTrust,Condor Instruments,Brazil) was used to record actigraphy data for 5-days. Raw data was analyzed by Software ActStudio (v.1.0.24) for average physical activity of the 10 most active hours (M10). Normality data was checked (Shapiro-Wilk-test), and a paired t-test and Pearson Correlation were performed. We observed an increase in total body mass (89.6±11.4 vs. 91.7±12.0kg; p=0.04) and in %FAT (23.2±6.8 vs. 25.3±7.3%; p=0.002) after winter. We also observed a reduction in in theM10 during the winter (4129.7±1095.0 vs 3004.2±1588.0 u.a.; p=0.02). No significant correlation was found between delta variation of M10 and %FAT (r=-0.34, p=0.33) or MC (r=-0.30, p=0.40). Overwinter at a research station in Antarctica resulted in a reduction in physical active behavior and changes in body composition, with increased adiposity. We suggest that future studies comprehend whether there is a relationship between dietary patterns and increased adiposity under similar conditions.

Funded by CNPq/MCTI/CAPES/FNDCT/PROANTAR: [442645/2018-0] and [440932/2023-8]; and CNPq/MCTI [408740/2023-0].

1165

The combined application of environmental DNA (eDNA) and organic geochemistry in prospecting penguin paleo-colonies on King George Island/Antarctic Peninsula

Dr. Cesar Amaral, MS. Rodrigo Barbosa, Mrs. Dafne dos Anjos, MS. Anna Donato, Dr. Heitor Evangelista

Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

Abstract

Due to its extremes in relation to climate, habitat and biogeography, the Antarctic region presents itself as an important open-air laboratory for various research related to fundamental life processes that present global implications. One of the main approaches employed for this type of study is related to the use of environmental DNA (eDNA) as a tool for prospecting and evaluating problems related to biodiversity. Using eDNA preserved in lake sediment cores, it enables the investigation of phenomena and the temporal monitoring of the effects of climate change on populations of some species. As a sensitive species to climate change, Antarctic penguins becomes an important taxon to be observed in monitoring the effects of climate change in Antarctica. This study focuses on analyzing sedimentary eDNA fluctuations in correlation with biogeochemical markers to assess the population dynamics of Antarctic penguins in a glacial lake located in the Ponta Turret region of King George Island, Antarctica. Our findings demonstrate a correlation between biogeochemical marker curves and eDNA quantities in the lake sediment core, mirroring the population trend observed in other studies involving the Gentoo Penguin (Pygoscelis papua). This interdisciplinary approach underscores the efficacy of combining eDNA analysis with biogeochemical tools for comprehensive ecological monitoring in glacial lacustrine environments.

1166

Antarctic Sea Ice Variability and the South Atlantic Subtropical High

Ricardo Potozky de Oliveira, Prof. Camila Carpenedo

Federal University of Paraná, Curitiba, Brazil

Abstract

The objective of this study is to investigate the relationship between Antarctic sea ice variability and the South Atlantic Subtropical High (SASH). Sea ice concentration (SIC; NSIDC/NASA) is examined through Empirical Orthogonal Functions (EOF). Mean sea level pressure data (MSLP; ERA5/ECMWF) are utilized to identify the SASH positions and intensities. EOF events with negative (positive) scores with ≤-1 (≥+1) standard deviation are evaluated. SASH positions and intensities in EOF events are analyzed accounting for time-lag effects. For EOF1 negative events, we observed a MSLP negative anomaly for September (lag=0). There is a greater SASH central position longitudinal variability in events of positive scores, with westward displacement. The SASH central position latitudinal variability is also higher in positive scores, with southward displacement. There is a greater SASH intensity variability in positive scores. At lag=1, a positive anomaly was observed at the SASH eastern branch, and persists a greater variability of the SASH longitudinal position in events of positive scores, but with less westward displacement. There is an inverted latitudinal observed pattern, with a northward SASH latitudinal displacement. There is an increase (decrease) in the SASH intensity in events of negative (positive) scores. For EOF2, at lag=0, we observed a MSLP anomaly dipole in the south of South Atlantic, associated with a Rossby wave train. There is a westward SASH central position displacement in events of positive scores, with a large variability of the longitudinal position (positive/negative scores). The SASH intensity variability is higher in events of positive scores, with lower central MSLP. At lag=1, a negative anomaly was observed at the SASH eastern branch. There is an inverted longitudinal observed pattern, with SASH eastern displacement in events with positive scores, and with less variability. There is also an inversion of the patterns observed for latitude and intensity.

1169

Changes in sleep and physical activity patterns during wintering at the Comandante Ferraz Antarctic Station

Ms. Nathalia Garcia¹, Ms. Mateus Rumão², Ms. Lurdilene Pinheiro², Carlos Costa³, Gabriel Benevenut³, Dra. Michele Moraes⁴, Dra. Rosa Arantes⁴, Dr. Thiago Mendes^1,2,5

¹Postgraduate Program Physical Education, Universidade Federal do Maranhão, São Luis, Brazil. ²Postgraduate Program in Science and Health, Universidade Federal do Maranhão, São Luis, Brazil. ³Marinha do Brasil, Rio de Janeiro, Brazil. ⁴Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. ⁵Postgraduate Program in Medicine and Health, Universidade Federal da Bahia, Salvador, Brazil

Abstract

Antarctica is one of the most challenging environments on the planet due to its isolated, confined. and extreme environment (ICE) conditions, which include low temperatures, strong winds, and extensive changes in the light-dark cycle between summer/winter. Prolonged stay in ICE can cause important physiological changes, including variations in sleep quality and physical activity behavior. Our objective was to analyze sleep patterns and physical activity of Brazilian overwintering personnel during their permanence at Comandante Ferraz Antarctic Station. Ten Brazilian military personnel (2021/2022) participated in the study. Data collection was carried out between January and August (UFMG Ethics Committee protocol 19092819.8.0000.5149). To analyze sleep and physical activity, a wristwatch (ActTrust,Condor Instruments,Brazil) was used for 5 days. The raw data was analyzed using ActStudio Software (v.1.0.24). The following sleep variables were analyzed: Bedtime, Time to get up, Time in bed, Total sleep time, Latency, Efficiency (%), Time awake after the sleep onset, and Number of awakenings, Physical activity - M10 and L5 for average activity of the 10 most active hours and the 5 least active hours, respectively. Data normality was verified (Shapiro-Wilk-test), and One Way ANOVA for repeated measures and Friedman's non-parametric test. In winter, we observed a delay in Time to get up (p<0.001), an increase in Time in bed (p<0.001), Total sleep time (p=0.001) and Time awake after the sleep onset (p= 0.047). For Physical activity, there was a reduction in (M10) and (L5) (p<0.05). During winter, we found changes in sleep patterns and physical activity, with delayed Awakening, increased Total time in bed and Sleep time, however, the episodes became more fragmented due to the increased time spent awake after the onset of sleep. Furthermore, there was a reduction in Physical activity.

Funded by CNPq/MCTI/CAPES/FNDCT/PROANTAR: [442645/2018-0] and [440932/2023-8]; and CNPq/MCTI [408740/2023-0].

1172

The role of the Antarctic Circumpolar Current on the distribution of the direct developer bivalve mollusc Gaimardia trapesina across the Southern Ocean.

Mr. Felipe Martínez^1,2, Dr. Claudio González-Wevar^1,2,3, Dr Sebastián Rosenfeld^2,3, Dr. Elie Poulin^2,3, Dr. Julia Saravia^1,2, Mr. Maximiliano Martínez^1,4, Mr. Marcelo López-Orellana^1,2

¹Universidad Austral De Chile, Valdivia, Chile. ²Instituto Milenio Base(Biodiversidad de Ecosistemas Antárticos y sub-Antárticos.), Santiago, Chile. ³Instituto de Ecología y Biodiversidad (IEB), Departamento de Ciencias Ecológicas, Universidad de Chile, Santiago, Chile. ⁴Instituto Milenio Base(Biodiversidad de Ecosistemas Antárticos y sub-Antárticos.), Valdivia, Chile

Abstract

A great variety of marine invertebrate species including molluscs, crustaceans, and macroalgae exhibit broad distributions across geographically separated sub-Antarctic provinces of the Southern Ocean. Most of the examples are a