In 2019 we collected gravity and magnetic measurements, in conjunction with multibeam swath bathymetry and multi-channel seismic reflection profiling, to characterize the neovolcanic zone around Orca Volcano in the Central Bransfield Basin, Antarctica. New analysis of mafic dredge samples shows that the caldera is composed of rocks with a wide range of measured susceptibilities. Multi-channel seismic reflection profiles across Orca Volcano showed the presence of several reflectors under the caldera, characterized by strong amplitudes and phase-reversed polarity. Gravity and magnetic data also show coincident anomalies. Our 2D forward modelling shows that these anomalies are the result of a shallow magma accumulation zone underlain by a low-density, low-susceptibility volume. We also observe that the axial ridge to the south-west of the volcano is characterized by a narrow zone of low density and high susceptibility, consistent with a focused rift axis. To the north-east of the volcano, the potential field data show that the axial rift is left-lateral offset and is somewhat broader. An asymmetric pattern of decreasing density and susceptibility of igneous rocks across the rift is consistent with a pattern of extension that has only recently evolved into a narrow rift and the mid-ocean ridge basalt-like compositions seen in dredge samples. These results are consistent with rifting that is rapidly transitioning to seafloor spreading.

Human activity in the Antarctic is supported by a wide network of government agencies, policies, businesses and workers back home. This polar workforce is particularly important in the so-called ‘Antarctic gateway cities’, which foreground their economic and cultural connections with the far south. Rather than focusing just on the Antarctic continent as the place of work, this paper therefore takes a broader approach by turning attention to the people back home that enable Antarctic logistics, modelling, policymaking and public awareness to be executed successfully. The paper outlines a matrix for mapping polar work capacity, with Antarctic roles classified as direct or indirect and as in situ or ex situ. By bringing together stakeholders from a range of Antarctic workplaces (including local and national government, academia, tourism and local business owners and training providers) from Christchurch (New Zealand) in October 2024, a workshop event identified the key challenges facing the Antarctic sector over the coming 5 years and highlighted areas where international collaboration could help to address these challenges into the future. Key suggestions include the implementation of an overarching Antarctic strategy; training and education to improve local talent and pathways; enhanced visibility of existing skillsets; establishing exchange opportunities across the Antarctic gateway cities; and developing Antarctic identities, including through tourism opportunities.

To date, there are few records of Holocene changes in sea ice in the south-eastern Weddell Sea, which limits our understanding of how sea ice has interacted with climate in this sector of the Southern Ocean. Here, we present a multi-proxy analysis of a snow petrel stomach-oil deposit that records occupation history and dietary fluctuations from ~1800 to 800 calibrated (cal.) yr bp. Lipid biomarkers (fatty acids (FAs), sterols and alkanols), bulk stable isotopes (δ13C and δ15N) and trace elements show distinct dietary shifts, which are linked to centennial-scale changes in summer sea-ice extent. From ~1730 to 1370 cal. yr bp, foraging in pelagic waters near the edge of the sea-ice pack is suggested by low nest occupation rates and Antarctic krill contributions to the diet. From ~1370 to ~1180 cal. yr bp, an increase in nest occupation and a fish-dominated diet reflect foraging within open water (polynyas) during a period of more extensive summer sea ice. A decrease in nest occupation after ~1180 cal. yr bp is attributed to local sea-ice readvance, resulting in reduced access to open water, impeding foraging success. Our results highlight the use of multi-proxy geochemical records from snow petrel stomach-oil deposits to reconstruct seasonal sea-ice fluctuations in the Weddell Sea and their interactions with late Holocene climate records.

This bibliometric study maps Antarctic microbiology research in South American countries using Web of Science records (1978–2024). A descriptive, quantitative design applied bibliometrix and VOSviewer, with thesaurus-based normalization reducing keyword variants by 6%, to construct a 1240-term science map. After manual screening focused on Antarctic (excluding sub-Antarctic) microbiology, 497 publications remained. Chile led the output (234), followed by Brazil (124) and Argentina (98). The leading journals for this output are Polar Biology, Frontiers in Microbiology and Extremophiles. Keyword and co-occurrence analyses revealed dominant themes of Pseudomonas and the bioremediation/biodegradation of heavy metals. The largest cluster, centred on Pseudomonas, was linked to oxidative stress, antioxidants, pigments, biofilms and polyhydroxyalkanoates, with a second major cluster focused on bioremediation. The findings indicate an applied orientation towards collecting biological materials and characterizing molecular/biochemical properties with commercialization potential. This study clarifies trends and gaps, informing future directions to facilitate international cooperation and advance the understanding of microbial diversity and functions across Antarctic habitats.

Concordia Station is a long-term lidar observatory in Antarctica. Its main purpose is to detect and classify polar stratospheric clouds (PSCs). In September 2023, water ice PSCs were observed for a period of 6 days. This has never occurred during the month of September in the 10 years of observations of PSCs at Concordia Station. In addition, the space-borne CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) lidar observed a rare occurrence of ice PSCs over Concordia Station during the first half of June. It is well known that the January 2022 eruption of the Hunga submarine volcano (20°32’S, 175°23’W) injected vast amounts of water vapour into the stratosphere. The Hunga hydration flooded southern high latitudes at the end of the 2022 austral winter, and the moist air was then entrained into the developing vortex in the austral autumn (April–May) of 2023. The increased water vapour from Hunga was reported to promote PSC formation by cooling the stratosphere and raising PSC formation temperatures. Here, we explore the impact of the Hunga eruption on the PSCs observed at Concordia Station.

The first fossil fauna to be described from the Antarctic was collected at Seymour Island in December 1892 by Captain Carl Anton Larsen and the crew of the Norwegian whaling ship Jason. Some specimens collected by Larsen’s crew were acquired by Charles Donald, the surgeon with an 1892–1893 Scottish whaling expedition from Dundee that was also operating in the vicinity of Seymour Island. Donald returned the fossils to Scotland, and they were described in two papers published by The Royal Society of Edinburgh (1894 and 1899) as, inter alia, two new species of Palaeogene bivalves and one of Cretaceous to Palaeocene age. Sadly, the described Palaeogene specimens are now lost, but one Cretaceous/Palaeocene survivor, the holotype of Lahillia larseni, has been located in the palaeontology collection of the British Geological Survey with the reference number FOR 4053. On Seymour Island, Lahillia larseni is a common species in both Upper Cretaceous and Palaeocene strata and is of particular importance as its abundance seems to have been unaffected by the end-Cretaceous extinction.

The McMurdo Dry Valleys in the Ross Sea Region of Antarctica represent a globally unique desert ecosystem where water availability is likely to change under global warming scenarios, thus influencing the distribution and abundance of biota. Using the Random Forest machine learning model, we focused on the spatial distribution of macroscopic terrestrial biota (moss, cyanobacteria, lichen, springtails and mites) in the Dry Valleys. A wetness index, explicitly driven by satellite-derived glacier surface temperatures and meltwater routing, was used along with biological survey data collected over six field seasons (2009–2014) as part of the New Zealand Terrestrial Biocomplexity Survey (n = 886 sites). Our analyses use the full extent of survey data available and include the larger Taylor, Wright and Victoria valleys, as well as data from the previously studied Miers, Marshall and Garwood valleys. The overall model accuracies were mixed (kappa statistic: 0.34% and 17.3% variance explained). However, the resulting predictive maps derived from the model and the influence of the different explanatory variables align with field observations and theoretical expectations. The models show that distance from coast was an important driver for the biota, as well as elevation and temperature. The predictive maps provide an initial model of the distribution of biota in the Dry Valleys and can guide future sampling as well as inform conservation and management strategies. Our research highlights the importance of biological survey data for use in spatial predictive modelling as well as the need to obtain representative samples from a wide range of different habitats (e.g. wet vs dry).

The Antarctic Peninsula is one of the regions in Antarctica that has experienced notable and extensively studied warming since the mid-twentieth century. Meteorological data, although limited and mostly dating back to the International Geophysical Year (1957–1958), reveal dramatic climate changes in both the Antarctic Peninsula and West Antarctica, with the Antarctic Peninsula showing the highest warming trends on the continent. One major manifestation of this warming is the increasing frequency and intensity of extreme warm events. This study utilizes temperature data from the Artigas Antarctic Scientific Base provided by National Weather Service, Uruguayan Institute of Meteorology (INUMET), which have not previously been used or quality-controlled. Data were processed and analysed, and a quality hourly database was built for the period 1 January 1998 to 11 December 2016 for the surface temperature, constructing a complete time series interpolating the data with two other nearby Antarctic stations (C.M.A. Eduardo Frei Montalva and King Sejong). Temperature presented an annual cycle with marked interannual and seasonal variability, with the cold season being the one with the highest variability and the largest anomalies, both positive and negative. No significant trend was found for the monthly mean temperature. A study of warm temperature events was conducted at three points on King George Island, defining warm events and extreme warm events as those in which the mean daily temperature was above the 90th and 99th percentile, respectively, for at least 3 consecutive days. A high frequency of occurrence was found (all years except 2015) mostly in the cold season of the year, and with large interannual variability. In turn, it was found that certain atmospheric dynamics favour the generation of these extreme warm events, and that their occurrence is higher during La Niña years. Although the majority of the extreme warm events occurred during positive phases of the Southern Annular Mode, the statistical correlations were not significant.

The present study has set up a pilot experiment to optimise the most promising assays for investigating the survival of Antarctic microbial cryptoendolithic communities – a natural astrobiological benchmark – when subjected to lethal/sub-lethal stresses testing viability, cell integrity and metabolic activity. Namely, the viability tests for culturable species are based on cultivation on a solid medium, while qPCR coupled to propidium monoazide (PMA) provides information of both culturable and non-culturable microorganisms. The fluorescein diacetate (FDA) and Adenosine 5’-TriPhosphate (ATP) assays, here optimised, consent to highlight the presence of metabolically active cells. The results revealed significant differences between the treated and untreated samples, proving the suitability of the selected tests for investigating the resilience of these astrobiological models.

There is clear evidence that rapid warming has been fuelling significant changes in the ocean and cryosphere in the Antarctic Peninsula region. Less is known about how terrestrial biological ecosystems, particularly plants, are responding to warming and hydroclimatic change. We show that high evaporative environmental conditions and microclimate associated with topography lead to humidity-dependent evaporative effects on the oxygen isotope ratios (δ18O) of moss waters and α-cellulose in the northern Antarctic Peninsula, based on a spatial (> 400 km) isotopic survey at 14 sites over 24 days during summer 2020. The δ18O of moss waters define a water line of δ2H = 4 × δ18O + 37 for Polytrichum strictum and δ2H = 3.8 × δ18O + 38.9 for Chorisodontium aciphyllum, indicating enrichment compared to line slopes ranging from 6.7 to 8.5 for snow, standing water, previous published snapshots of moss waters and the long-term local meteoric water lines along the Antarctic Peninsula. The δ18O of moss waters negatively correlated with relative humidity (which ranged from ~50% to 100%) and not with temperature or latitude, where a higher δ18O indicates increased evaporative enrichment or dry conditions. A positive correlation between the δ18O of moss waters and α-cellulose (ρ = 0.397, P = 0.011) for P. strictum (ρ = 0.533, P = 0.007) but not C. aciphyllum suggests that the high evaporative conditions from the season imprinted on the cellulose. Lastly, we found significant positive correlations between topographic aspect (north-exposedness) and the δ18O of moss waters (ρ = 0.569, P < 0.001) and α-cellulose (ρ = 0.579, P < 0.001), indicating that irradiance on north-facing slopes promotes drier conditions and evaporative enrichment. Topographic aspect (and resulting microclimate) is an important and predictable determinant of the δ18O of moss waters and α-cellulose. This study highlights that mosses are sensitive recorders of climatic and non-climatic conditions in polar terrestrial ecosystems.

The highest-elevation and a far southern pond in the Transantarctic Mountains is briefly documented. The small pond, at an elevation of ~2350 m, was frozen when it was visited in the 1963–1964 field season, and satellite imagery suggests it has remained frozen since 2010. A second frozen pond is noted, but its precise location is uncertain.

The population status of Adélie penguins (Pygoscelis adeliae) on the Antarctic Peninsula highlights opportunities for the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) to address uncertainty more directly and effectively in its conservation efforts. The heightened uncertainty posed by climate change is testing CCAMLR’s commitment to balancing science and international cooperation in decision-making. Uncertainty underpins some of the justification to postpone reaching a consensus on the establishment of Marine Protected Areas, leaving Adélie penguins vulnerable to change. Two key opportunities to adapt current management approaches emerge: 1) reduce uncertainty by systematically identifying knowledge gaps within CCAMLR’s processes; and 2) integrate uncertainty more explicitly into decisions through a standardized approach to assessing and communicating it.

A Doppler Sonic Detection and Ranging (SODAR) wind-profiling system was deployed at Jang Bogo Station, Antarctica, during the summer of 2017. The parameters measured by the SODAR system were wind speed and direction averaged for 15 min from 30 m above the surface to 500 m aloft. Additionally, wind measurements obtained from the nearby walk-up tower and automatic weather station (AWS) were also used for additional data and comparison, respectively. The analysis and comparison used hourly average for consistency. The mean wind speed obtained from the SODAR measurement is highly correlated with those from the walk-up tower and the AWS measurements. All three measurements recorded westerlies during all strong wind events but varied during calm periods. The measurements also reveal that Jang Bogo Station experiences lower wind speeds compared to the nearest katabatic confluence region (Inexpressible Island), where the maximum airflow usually occurred. From the hourly averaged data, SODAR only detected a maximum wind speed of 18.1 m s−1. There were 238 occurrences of strong wind events equal to or above 10.8 m s−1 (Beaufort scale 6) from 10 May to 31 October 2017. These occurrences were recorded in 50 out of 175 days analysed in this study. From 10 to 12 June 2017, predominantly south-westerly-westerly winds were recorded at the surface and aloft during two strong wind events. Based on this case study, the boundary layer during calm and strong wind periods was also analysed.

Maritime Antarctica experiences less extreme environmental conditions than much of the Antarctic continent and has further been impacted by considerable warming in recent decades. While inventories exist of macroscopic Antarctic biodiversity, and there is some information available on culturable microorganisms, much less is known about the presence of other cryptic eukaryotic organisms. DNA metabarcoding provides a method for assigning the DNA of multiple different organisms simultaneously from environmental samples. In this study, we used DNA metabarcoding to investigate the environmental DNA (eDNA) diversity of non-fungal eukaryotic organisms associated with rocks in the South Shetland Islands. Five sampling points were selected from a stratigraphic profile at Mazurek Point, King George Island. Collected rock samples were pulverized, total DNA was extracted and amplicons were generated using ITS2 primers, then these were sequenced using an Illumina MiSeq system. Sequences representing five kingdoms and nine phyla were retrieved. Viridiplantae was the most diverse and abundant group, with 42 assigned taxa, followed by Chromista, with 22 assigned taxa. The precise lithology did not influence the assigned diversity. The majority of assigned taxa are widespread and plausibly present in the area, but some are not known from Antarctica, including some from tropical regions. The latter assignments probably result from the limitations of the databases used, although in some cases they may indicate evidence of anthropogenically associated or naturally dispersed DNA-containing material.