Reproductive synchrony is common in populations that inhabit seasonal environments where reproductive timing is important to offspring survival. Weddell seals (Leptonychotes weddellii) reproduce in strongly seasonal Antarctic environments and are known to exhibit reproductive synchrony that varies by latitude, whereby more southerly populations give birth later. The Erebus Bay population of Weddell seals is the southernmost mammal population in the world, and birth-date synchrony has been demonstrated in this population. Various life history correlates including sex, maternal age and reproductive status have been identified as predictors of birth timing, but all prior work has been done on pups born to locally born mothers. Immigrant females originating from unknown sites in more northerly locations also produce pups in Erebus Bay and may have different birth timing due to the earlier average birth dates in their natal colonies. Using 22 years of capture-mark-recapture data for Weddell seals in Erebus Bay, we aimed to assess whether the timing of birth dates for pups born to immigrant mothers differs from that of pups born to locally born mothers. To our knowledge, this is the first time that such a comparison has been studied in a wild population. Birth dates were examined using Bayesian linear regression. We analysed birth dates from 7539 pups (4932 from locally born mothers, 2607 from immigrant mothers) born to 2210 mothers (1254 locally born, 956 immigrant) and found that there were no biologically impactful differences in the birth dates of pups born to locally born or immigrant mothers. Additionally, birth-date patterns for immigrant mothers were similar to those for locally born mothers with respect to various traits. Our results demonstrate that immigrant Weddell seal mothers can synchronize birth timing with locally born mothers. More research is required to understand the underlying mechanisms that allow for immigrant seals to achieve birth-date synchrony.

Emperor penguins are highly reliant on stable fast ice for successful breeding, and some studies project possible quasi-extinction for most colonies by 2100 due to future sea-ice loss. To better understand the future response of emperor penguins to ocean-climate warming and the possibility of major changes to their habitat, it is essential to better understand how colonies have responded to past changes in ice conditions. In this study, we identify the historical locations of the SANAE, Astrid and Mertz colonies in all available Landsat 4–9, Advanced Spaceborne Thermal Emission and Reflections satellite (ASTER) and Sentinel-2 imagery for the period 1984–2024. We record the location and surface type of the colonies’ breeding locations each year while also recording major calving events, early fast-ice breakouts, distance to the fast-ice edge, and colony location span within a season. The results show that colonies usually return to approximately the same sites annually, but we observe variations due to major calving events. Following such events at Mertz (2010) and SANAE (2011), colonies relocate to different sites, where they may be more vulnerable to early fast-ice breakout or must travel longer distances to the fast-ice edge. In subsequent years, the colonies eventually return to sites close to their original location. Additionally, we observe early fast-ice breakouts that may impact breeding success at Mertz and SANAE colonies, including as early as September at Mertz (2016). Such breakouts coincide with both broader sea-ice lows and variations in colony location. Furthermore, all three colonies move onto the adjacent ice shelf in some years (and at Astrid and Mertz, also icebergs), including when stable fast ice is available, suggesting that this behaviour may be more common than previously thought. Observation of these behaviours contributes to broader understanding of emperor penguins’ adaptability and will aid future efforts to model the response of the species to ice loss.

The diverse cutthroat eel family Synaphobranchidae comprises 13 genera and 57 species of mostly deep-sea fishes documented from all oceans. Here, we report on the catch of a single synaphobranchid specimen in the Kong Haakon VII Sea off Dronning Maud Land, representing the first record of the genus Ilyophis in the Southern Ocean. The specimen was trawled at a depth of 1500 m during the 2019 joint expedition of the Norwegian Polar Institute, Institute of Marine Research (Norway), the University of Bergen (Norway), the Arctic University of Norway, the University of Science and Technology (Norway) and the Stellenbosch University (South Africa) onboard the Norwegian research vessel Kronprins Haakon. The specimen is deposited in the ichthyological collection of the University Museum Bergen. In this study, we tentatively identify the specimen as Ilyophis cf. maclainei based on an integrative taxonomic approach. Phylogenetic analysis of mitochondrial partial cytochrome oxidase I places the Antarctic specimen in a clade of sequences deposited in Barcode of Life Data System (BOLD) as Ilyophis sp., Ilyophis cf. brunneus and Ilyophis brunneus. Morphological data show overlaps in some morphometric and meristic characters with I. brunneus and the recently described I. maclainei - with no genetic samples currently being available for the latter. Our analysis reveals taxonomic issues within I. brunneus and the need for increased sampling and a worldwide taxonomic revision of I. brunneus. The full mitochondrial DNA of the Antarctic specimen is reconstructed as a resource for future research.

Located in the central part of the Western Antarctic Peninsula, the Argentine Islands-Kyiv Peninsula region is a hotspot of moss diversity, with 51 species and one variety currently known. However, no studies have specifically addressed the distribution of rare mosses in this region. Applying the only definition of moss rarity currently available for Antarctica, we identify very rare (one to two unique occurrences) and rare (three to five unique occurrences) moss species in the region and present a biogeographical analysis of their spatial distribution with corresponding maps, based on a comprehensive synthesis of archival published occurrence data. Of the 51 recorded species, 23 were classified as locally very rare or rare. Cape Tuxen, Galindez Island, Darboux Island and Cape Pérez hosted the highest concentrations of rare moss diversity, with eight, seven, seven and six species, respectively. Five rare species were recorded at Petermann Island, four at Booth and Lahille islands and three each at Diorite, ‘Eight’ and Uruguay islands. Additionally, several locations hosted species with unique characteristics, including their only known occurrence in the Antarctic Peninsula or at their known range edge. Very rare and rare species assemblages showed only partial overlap among sites: the four most species-rich sites shared several taxa, but no species occurred at all sites. Uruguay, Diorite and ‘Eight’ islands together represented a full moss species pool of the four most species-rich sites. In addition, some sites supported distinct species not recorded elsewhere in the region. Notwithstanding the limitations of the available survey data, these findings highlight the regional significance of the Argentine Islands-Kyiv Peninsula region within the Western Antarctic Peninsula for moss diversity in terms of the recognized criteria required for developing proposals for formal protection under the Antarctic Treaty.

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).

Deception Island is an active, caldera-forming volcano whose surveillance is critically constrained by its extreme Antarctic isolation, scarce resources and limited seasonal human access. This study addresses these challenges by presenting an innovative Global Navigation Satellite Systems (GNSS) geodetic surveillance framework specifically adapted for such a remote environment. Our approach establishes a key operational distinction between non-real-time monitoring and near-real-time surveillance via a semi-continuous wireless network. We effectively resolve the inherent trade-off between promptness and precision by applying signal enhancement methods (e.g. Kalman filtering) to maintain millimetric accuracy in deformation detection, even when utilizing the high sampling rates (1 Hz) essential for rapid assessment. The resulting model allows for the rigorous isolation of the local volcanic signal from the complex regional tectonic kinematics. Crucially, data analysis reveals recurrent 3 year cycles of inflation and deflation in the magmatic system, strongly correlated with seismicity, which validates ground deformation as a reliable volcanic precursor. The primary practical advance is the validation of a dual-term hazard forecasting system: 1) mid-term (months) forecasts based on long-term time-series analysis to facilitate safe inter-campaign operations and 2) short-term (days) forecasting during periods of unrest using ground displacement acceleration, complemented by a magma injection model to predict the spatial location of potential vent openings. This validated and technologically adjusted framework provides an optimized and transferable template for continuous geodetic surveillance in other isolated, active polar volcanoes.

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.

In recent decades, the extent of ice-free areas has been increasing in the South Shetland Islands (Maritime Antarctica). The coastal sector is one of the zones most significantly affected by glacial retreat, with newly exposed land surfaces undergoing a wide variety of post-glacial environmental processes. Coastal areas are characterized by both continental and marine ice dynamics, which in turn have major influences on the morphology and processes shaping coastal landforms. A detailed geomorphological analysis was carried out at Spanish Cove, south-west Livingston Island, which constitutes a boulder beach close to the Spanish Antarctic Station Juan Carlos I. This research provides a classification of the existing coastal landforms in this sector, as well as an analysis of the recent behaviour of the area using drone surveys, material size measurements obtained through semi-automatic techniques and hardness analysis using a durometer. This study represents one of the first attempts to classify the Antarctic coastal environment and offers a basis for understanding the potential evolution of such environments over the coming decades under global change and the rapid transformation of present-day glaciated landscapes.

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.

Coastal erosion is a dynamic process driven by multiple environmental factors. In Antarctic regions, the interaction between wind, waves, sea ice, sediment transport and precipitation creates a complex setting for understanding shoreline change. This study focuses on Potter Cove, a small fjord in Maxwell Bay, south-west of King George Island (South Shetland Islands), where winter waves are investigated as a key erosive driver. Shoreline changes were assessed through satellite imagery, in situ beach profiling and sediment sampling. Additionally, a numerical wave modelling system was implemented to simulate wave dynamics within the cove. The results indicate a coastal retreat of up to 20 m along the southern shore of Potter Cove since 2020. Simulations for winter 2021 reveal two high-energy wave events with significant wave heights (Hs) of ~2 m, along with eight moderate events (Hs ≈ 1 m) occurring within the cove. The most energetic events (Hs = 2.11 m) originated offshore and entered directly through the cove’s mouth from the west-south-west. Conversely, moderate waves could be generated both internally and externally. Reduced sea-ice cover probably diminished the natural wave-buffering effect, enhancing the erosive impact of wave action on the coast. However, the absence of quantitative assessments of other relevant processes (e.g. permafrost thaw, glacial meltwater discharge, sea-level variability and sediment supply) limits our ability to gain a comprehensive understanding of the ongoing erosion. These findings highlight the role of wave dynamics in Antarctic coastal change and the need for integrated monitoring approaches.

The Fremouw Formation of the Central Transantarctic Mountains preserves the southernmost record of Early to Middle Triassic terrestrial ecosystems that developed in the aftermath of the end-Permian mass extinction. Although the well-studied vertebrate fossil assemblage in the lower member of the Fremouw Formation provides a detailed snapshot of subpolar ecosystems immediately following the end-Permian mass extinction, the nature of how long these earliest Triassic communities persisted at the southern extremes of Pangaea is virtually unknown. Importantly, the timing and extent of the major faunal turnover between the lower and upper members of the Fremouw Formation have been obscured by the paucity of fossil specimens historically recovered from the middle member. Here, we describe the first vertebrate assemblage from the middle member of the Fremouw Formation, including occurrences of procolophonids (including Procolophon trigoniceps) and archosauromorphs (including Prolacerta broomi), as well as infilled vertebrate burrow casts referrable to the ichnogenus Reniformichnus. We also summarize and expand on lithostratigraphic shifts between the lower, middle and upper members of the Fremouw Formation. Although the sample size of vertebrate body fossils is small compared to the lower and upper members of the Fremouw Formation, we discuss the evidence for a taphonomic shift between the lower and middle members of the Fremouw Formation that favours preservation of smaller-bodied taxa and individuals in the latter. Together, these preliminary data add crucial context to the persistence of subpolar vertebrate communities in the earliest Mesozoic.