The Antarctic seaspider Pentanymphon antarcticum is a benthic species in the Southern Ocean, but little is known about its pathogen profile. In this study, we provide a draft genome for a new iridovirus species that has been identified using metagenomic techniques. The draft genome totals 157 260 bp and encodes 188 protein-coding genes. The virus shows greatest protein similarity to a ‘carnivorous sponge-associated iridovirus’ from a deep-sea sponge host. This study represents the first discovery of a pycnogonid iridovirus and the first iridovirus from the Antarctic region.

Sea ice, and particularly land-fast sea ice, is crucial for emperor penguins as a breeding and moulting platform and foraging habitat (Barbraud & Weimerskirch 2001). Emperor penguins use land-fast sea ice as a breeding platform to raise their chicks, from egg hatching in late July to mid-August until fledging, typically between mid-December and early January.

Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛNd, 87Sr/86Sr and ɛHf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous.

Due to the limited landmasses in the Southern Hemisphere, we must rely on data from sub-Antarctic islands within the Southern Ocean to record historical climate patterns. Over the past few decades, glaciers throughout the Southern Ocean region have experienced a noticeable retreat, especially in the Kerguelen Archipelago, whose glacial landforms offer valuable insights into long-term climate fluctuations. Our comprehensive glacial geomorphological study conducted in its remote north-western region meticulously examines morainic complexes from smaller cirque glaciers and larger outlet glaciers stemming from the Cook Ice Cap. We mapped these landforms to reconstruct historical glacier extents during the Holocene. The surface area of the three main glaciers had decreased in 1962–1964 by only 35% compared to their maximum extents, whereas surface area changes across 12 time intervals spanning from 1962 to 2019 from aerial and satellite imagery reveal a cumulative reduction of 43.5%. Additionally, we modelled changes in glacier thickness and equilibrium-line altitude for the key glaciers at three distinct stages: 1) their maximum extent before 1962, 2) the early 1960s and 3) 2019. This multifaceted analysis contributes valuable insights into the dynamics of Kerguelen's glaciers and the broader implications for understanding past and ongoing climate dynamics in the Southern Hemisphere.

Individual trophic specialization (ITS) refers to the trophic diversification amongst individuals within a population. The gentoo penguin (Pygoscelis papua) is considered a trophic generalist at the population level, but little is known about its individual trophic differentiation. We assessed the degree of ITS at one of its main breeding colonies: Ardley Island, South Shetland Islands. We used skin from 19 dead individuals to determine species and sex by molecular methods and a nail for stable isotope analysis of δ15N and δ13C. Isotopic niche metrics and ITS were estimated for the population and for each sex. We found a moderately high degree of ITS associated with the trophic position of the resources consumed (δ15N) for the population and both sexes, as well as a moderate degree of ITS in the foraging habitat (δ13C) for the population and females. Females showed a higher exclusive niche area, suggesting that they use resources and foraging areas that males do not, probably related to reproductive energy demands. Given the high population density of this species, ITS could function as a mechanism to decrease intraspecific competition. This combination of genetic and isotopic tools allowed us to provide relevant information on the trophic ecology of the gentoo penguin without manipulating animals or using invasive methods.

In March 1912, Captain Robert Falcon Scott and his companions perished on their return journey from the South Pole. The Final Blizzard delivered a terminal blow. However, it was only a part of this story of endurance and tragedy. In December 1911, en route to the South Pole, the men had been tent-bound for 4 days due to an exceptionally warm, wet blizzard. This article compares the meteorological situation that the polar party encountered in December 1911 to a similar situation in the modern time and suggests a possible climatology behind the 1911 event.

The Vestfold Hills are a 400 km2, isolated ice-free oasis in eastern Antarctica featuring large areas with translucent quartz rocks that provide habitat for hypolithic microbial communities underneath. We used high-throughput DNA sequencing of 16S and 18S ribosomal RNA amplicons to characterize bacterial and eukaryotic hypolithic communities across the Vestfold Hills. We found high-level, local heterogeneity in community structure consistent with limited dispersal between hypoliths. Hypolithic communities were dominated by heterotrophic Bacteroidetes (mean bacterial relative read abundance: 56%) as well as Cyanobacteria (35%), with the eukaryote component often dominated by Chlorophyta (43%). Small but significant proportions of the variation in microbial community composition and function were explained by soil salinity (5–7%) and water availability (8–11%), with distinct taxa associated with different salinities and water availabilities. Furthermore, many inferred bacterial metabolic pathways were enriched in hypolithic communities from either dry or high-salinity sites. Vestfold Hills hypolithic habitats are likely to be local refuges for bacterial and eukaryotic diversity. Gradients in soil salinity and water availability across the Vestfold Hills, in addition to the number and diversity of lake types and fjords as potential source populations, may contribute to the observed variation in the extremophile, hypolithic microbial community composition.

We investigate two ice rises, Kupol Moskovskij and Kupol Ciolkovskogo, in the Fimbul Ice Shelf, East Antarctica, situated ~60 km from each other but differing in their glaciological settings. We apply a thermo-mechanically coupled Elmer/Ice model to profiles going across these ice rises and use it to investigate their past evolution covering present to several millennia ago. We constrain the model results using field measurements, including surface-velocity measurements, and surface mass balance estimated by isochronous radar stratigraphy dated with firn cores. We find that the ice rises are thickening at present (2012–2014), which started only in recent decades. Investigation of deeper radar reflectors suggests a stronger upwind-downwind contrast in surface mass balance in the past for both ice rises, with varying details. This result matches what was previously found on Blåskimen Island ice rise, which is also in the Fimbul Ice Shelf. Moreover, Kupol Moskovskij, situated at a shear margin, shows signs of recent changes in its ice-divide position, while Kupol Ciolkovskogo shows a more stable divide position. This study highlights the long-term influence of surface mass balance on ice rises, as well as the strong influence of local glaciological settings on their evolution.

Antarctic ice-free areas are dominated by wind-dispersed organisms. However, which organisms arrive and circulate in Antarctica and how remain poorly understood. Due to their 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 compositions and impacting the native biota. We used DNA metabarcoding to identify non-fungal eukaryotic DNA present in the air that could potentially reach and circulate in Antarctica. Air was sampled near the Brazilian Comandante Ferraz Antarctic Station on King George Island between December 2019 and January 2020. Sequences representing a total of 35 taxa from 10 phyla and 3 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 was recorded only on Deception Island. Metabarcoding revealed the presence of previously undocumented airborne diversity, suggesting that the Antarctic airspora includes propagules of both local and distant origin.