Published and unpublished data are used to investigate possible mechanisms of species diversification in two key groups of Antarctic organisms: the Notothenioidei and the Euphausiidae. Species distributions are mapped onto molecular phylogenies, and this evidence is interpreted in light of the various ecological and historical factors which characterize the Southern Ocean. The joint effect of diverse agents (vicariance, “jump” dispersal) appears to be determinant in several cases for species divergence. A review of results from population genetics studies, together with new molecular evidence, confirm the importance of physical barriers (oceanographic fronts) in reducing migration, thereby promoting speciation, at least in notothenioids.

The stomach contents of demersal fish in late January 1982 were analysed. Samples were taken at 100, 300 and 500 m depth south of Elephant Island, Bransfield Strait and north of Livingston Island, and at 800 m to the east of Smith Island. Fifty four taxa of fish belonging to 11 families were collected. The diets of 2101 fish representing 38 taxa were examined. These were classified into three categories, fish feeders, krill feeders and benthos feeders. Fish prey species fed on krill and/or benthos. Krill was a major dietary component for 32 (84.2%) out of 38 taxa. Gobionotothen gibberifrons was distributed at all 10 stations (100–800 m in depth) and its diet comprised krill and benthos. The present findings verify the importance of krill in the Antarctic marine ecosystem and indicate that krill is consumed by benthic fish at greater depths than previously reported.

Cycling of deepwater silicon (Si) within the Southern Ocean, and its transport into other ocean basins, may be an important player in the uptake of atmospheric carbon, and global climate. Recent work has shown that the Si isotope (denoted by δ29Si or δ30Si) composition of deep sea sponges reflects the availability of dissolved Si during growth, and is a potential proxy for past deep and intermediate water silicic acid concentrations. As with any geochemical tool, it is essential to ensure analytical precision and accuracy, and consistency between methodologies and laboratories. Analytical bias may exist between laboratories, and sponge material may have matrix effects leading to offsets between samples and standards. Here, we report an interlaboratory evaluation of Si isotopes in Antarctic and sub-Antarctic sponges. We review independent methods for measuring Si isotopes in sponge spicules. Our results show that separate subsamples of non-homogenized sponges measured by three methods yield isotopic values within analytical error for over 80% of specimens. The relationship between δ29Si and δ30Si in sponges is consistent with kinetic fractionation during biomineralization. Sponge Si isotope analyses show potential as palaeoceaongraphic archives, and we suggest Southern Ocean sponge material would form a useful additional reference standard for future spicule analyses.

Approximately 54% of the world population of southern elephant seals (Mirounga leonina) breeds at South Georgia. A partial survey in 1951 and a complete survey in 1985, together with counts at specific sites between these times, suggested that the population (around 100 000 breeding females) had not changed significantly in 34 years. This was in contrast to marked declines in most other populations. To examine this further, we conducted a third survey in 1995. This produced an estimate of 113 444 (se = 4902) breeding females. Taking into account improved information about the behaviour of female elephant seals since the survey in 1985, there was no significant change in the number of breeding female elephant seals between 1985 and 1995. When combined with information from the 1951 survey, this supports the view that the total population size has not changed significantly during the past 45 years. Evidence for regulation of the population by environmental factors is equivocal. We hypothesize that the lack of any net change in population size may be linked to a limited availability of high quality breeding habitat.

Botany Bay is one of the richest sites for lichen and bryophyte biodiversity in continental Antarctica. A total of 29 lichen, nine moss and one liverwort species have been identified. The most extensive vegetation occurs on a sheltered raised beach terrace. Vegetation associations are described and compared to other continental Antarctic localities that also possess a rich vegetation cover. Ordination analysis clearly indicates the importance of the type of water supply, its regularity, the substrate type, and particularly in Botany Bay, the influence of nutrients derived from the local bird population in governing plant distribution and associations. A vegetation map has been produced and can be used as a baseline to assess vegetation changes over time.

Non-krill prey remains were recovered from ornithogenic sediments at three active Adélie penguin colonies on Ross Island, to assess long-term dietary trends in this species. Radiocarbon dates place the age of these deposits from a maximum of 947 years ago to the present. We identified 12 taxa of fish and two of squid with the Antarctic silverfish (Pleuragramma antarcticum) as the most abundant prey species represented at all sites. In addition, silverfish have decreased in importance in Adélie penguin diet over the past 600 years, perhaps in response to climate change since the onset of the Little Ice Age, though it remains much more abundant in current penguin diet in the Ross Sea than in the Antarctic Peninsula. Other prey taxa reflect the diversity of prey selection by Adélie penguins in Antarctica.

The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.

Despite small direct anthropic/anthropogenic influence, Antarctica cannot be considered out of the reach of pollutants. The present study evaluated the distribution and transfer of the following organic pollutants: PCBs (polychlorinated biphenyls), organochlorine pesticides and PBDEs (polybrominated diphenyl ethers) in invertebrates, fish, bird eggs and liver samples from Admiralty Bay, King George Island, South Shetland Islands. The prevailing compounds were (in ng g-1 wet weight for species averages): PCBs up to 1821 for birds, 6.82 for fish and 41.3 for invertebrates, HCB (hexachlorobenzene) up to 69.8 for birds, 0.66 for fish and 0.56 for invertebrates and DDTs (dichlorodiphenyltrichloroethane) up to 524 for birds, 3.04 for fish and 0.74 for invertebrates. PBDEs (detected only in bird eggs and liver, up to 39.1 and 7.95, respectively) occurred in levels one or two orders of magnitude lower than organochlorines, probably due to the lower and more recent usage of PBDEs. The qualitative profiles of PCBs agree with trophic level and diet data. PBDEs showed small difference in composition when compared to the technical product available in the Americas, especially in endemic species, which could indicate that fractionation does not have a major role for this contaminant group. Trophic level, but also and more importantly, diet, range, ecological niche and “growth dilution” effect explain the variation of pollutants concentrations found in this study.

An extremely dynamic chain of archipelagos links South America and the Antarctic Peninsula. It includes islands, which are large and small, old and young, near continental margins and isolated, and well sampled and poorly known. The current study sampled the macrobenthos of all the major archipelagos of this arc at shelf and slope depths using an Agassiz trawl. At least four samples (200 m, 500 m, 1000 m and 1500 m) were taken down-slope at Falkland Trough, Shag Rocks, South Georgia, South Thule, Powell Basin, Elephant Island, and Livingston Island sites and one sample was collected in the caldera of Deception Island. Despite the biogeographical and biodiversity importance of this region, this is the first time (by definition) entire standardized trawl samples have been analysed from all its archipelagos and at any consistent taxonomic level. We found 15 phyla and 29 classes of macro- and megafauna in total across the samples, many of which occurred at all sites. Even at remote and geologically young sites richness was high. Richness increased with abundance and wet mass and was highest in the shallow shelf samples and lowest at 1500 m. Abundance and wet mass varied more than two orders of magnitude, even within classes or study areas. There were strong similarities between the ascidian dominated shallow faunas of the two active volcanic sites, Southern Thule and Deception Island despite huge differences in isolation. There were also strong faunal similarities between Falkland Trough and Shag Rocks despite being on opposing sides of the Polar Front. In contrast two near neighbours with similarly soft substrata, Elephant and Livingston islands were amongst the most dissimilar.

Infrared satellite images of the coastal area off Adélie Land were examined together with two wind data sets, one from the manned French station, Dumont d'Urville, the other one from an Automatic Weather Station (AWS) during the 1986 austral winter. A correlation between the development of open water areas (polynyas) and the appearance of extremely strong offshore winds can be drawn. The wind direction tended to be more perpendicular to the coastline during these extreme ‘events’, suggesting a katabatic origin of the increase in wind strength. In the study area the influence of the katabatic wind on the sea ice extends 20–100 km offshore. Sea ice motion further off the coast seems to be more dominated by synoptic scale weather systems. Broader scale atmospheric influences may create large polynya structures which influence the development of coastal winds, as the temperature contrast between open water and the cold continent generates its own circulation. Strong wind events can have a weakening effect on the coastal sea ice which can lead to a much more sensitive reaction of the sea ice in response to following anomalous wind events.

We investigated nutrient composition and the potential for greenhouse gas production in Antarctic penguin guano, ornithogenic soils and seal colony soils through a laboratory incubation experiment. Total organic carbon contents ranged from 0.2–14.7% and total nitrogen contents ranged from 0.05–3.60% across all the samples. Penguin guano and the soils had the δ13Corg values of -28.4‰ to -22.8‰ and highly enriched δ15N values (8.28–35.51‰), indicating a rapid N cycling in local ecosystems. The mean CO2 and CH4 emission rates from penguin guano were significantly higher than those from the soils under aerobic or anaerobic conditions. The CO2-C/TOC rate indicated that the bioavailability of TOC was markedly higher in penguin guano than in the soils. These soils showed higher N2O emission rates under anaerobic conditions, indicating that denitrification may be the major process in N2O emission. The CO2 and CH4 emissions have a significant correlation with TOC in both penguin guano and the soils. Our results show that marine animal excreta are an important factor determining storage and composition of nutrients in coastal Antarctica, and that they may considerably affect current and future net fluxes of greenhouse gases in this region.

To date, Antarctica is the only continent to have escaped the COVID-19 pandemic. This was facilitated by the continent's isolation and low human presence, combined with the global emergence of the pandemic at the end of the Antarctic summer season and the rapid action of those national governmental operators and other actors still active on and around the continent during the early phases of the outbreak. Here, we consider the implications of the pandemic for Antarctic governance, national operator logistics, science, tourism and the fishing industry, as well as for Antarctic environmental protection. Global disruption will result in a temporary decrease in human activity in Antarctica, in turn leading to a reduction in environmental impacts for a period, but also a reduced capacity to respond to environmental incidents. Given the diversity of transmission routes and vectors, preventing the introduction of the virus will be difficult, even with stringent quarantine procedures in place, and the risks and implications of virus transmission to Antarctic wildlife are largely unknown. With control of the pandemic a major global challenge, international cooperation will be essential if Antarctica is to remain free of coronavirus.

The freshwater streams of James Ross Island share many of the features common to other Antarctic streams. There is a diel variation in temperature and discharge, which follows the daily insolation cycle; catchments are barren; stream vegetation is predominantly algal, comprising mat-forming cyanobacteria and filamentous chlorophytes; and physical factors, particularly turbidity and bed stability are important in determining biomass and composition of algal assemblages. Nutrient concentrations vary from stream to stream and over a diel cycle, with minimum dissolved N in late afternoon. Biomass attained and photosynthetic and respiratory rates are also comparable to those recorded in other Antarctic streams, with low productivity/biomass ratios in perennial assemblages.

Are we failing to acknowledge the impact of global changes (e.g. UVB, invasive species, climate, land use, atmosphere) on the terrestrial biodiversity and ecosystem processes of Antarctica? Antarctica is considered a pristine environment and has low terrestrial species diversity and trophic complexity, and yet while scientifically possible, we still do not know the number of species, where they are, or how their influence on ecosystem processes (e.g. nutrient cycling, carbon flux, decomposition, feedbacks to climate, hydrology) will be affected by multiple global changes. Increased recognition of human dependence on services provided by biodiversity and ecosystem functioning combined with documented impacts of global change already occurring on Antarctic soil ecosystems, increases the urgency to expand investigations regionally in Antarctica. We cannot measure the effects of global change or sustainably manage Antarctica's future if we underestimate the contribution of soil communities. Evidence indicates habitats of rocky moraines, soils and cyroconite holes of glaciers in the continental interior may host not only microbes, but also a complexity of algae and invertebrates. Scientists of many disciplines, together, need to assess the benefits humans derive from Antarctic terrestrial biodiversity and ecosystem processes, how these will be affected by global change, and link their findings to the rest of the world.

This paper describes a major calving of the Ninnis Glacier tongue in January 2000. This event, which took 10 years to complete, produced a major change in the George V Land coastline and a large iceberg (∼800 km2). By grounding or becoming “locked in” by fast ice, bergs produced locally and drifting in from afar reside for long periods (10–20 years) in the region ∼146 to 154°E to have a profound impact on sea ice distribution, both locally and 100s of kilometres up- and downstream. They are responsible for the formation of a lens of thick perennial ice to the east (∼14 000 km2 in area), and polynyas. Iceberg movement is sporadic, with intermittent ungroundings of large bergs occurring every 5–13 years. “Escaping” bergs have a temporary impact on the Mertz Glacier polynya to the west. Although public attention focuses on vast bergs, assemblages of small bergs appear to be equally important in terms of their impact on regional fast and pack ice distribution. Possible global change scenarios are discussed. The need for field observations and improved bathymetric and oceanographic data is emphasized.

Cold tolerance of the springtail Gomphiocephalus hodgsoni Carpenter (Collembola: Hypogastruridae) was studied at Cape Bird, Ross Island, Antarctica (77°13′S, 166°26′E). Microclimate temperatures indicate a highly seasonal thermal environment, with winter minima <–39°C. Snow cover significantly buffers both minimum temperatures and cooling rates. Gomphiocephalus hodgsoni survives low temperatures by avoiding freezing. Mean low group supercooling points (SCPs) ranged from –35.4°C in October to –28.3°C in January. The lowest SCP measured was –38.0°C. The high SCP group was very small, making up only 18% of the population in January. In October, G. hodgsoni had a very high glycerol content (>80 μg mg−1 dry weight), although this declined rapidly to low levels (c. 7–10 μg mg−1 dry weight) in January. Quantities of glucose and trehalose were low during October, but steadily increased throughout the summer. Haemolymph osmolality was exceptionally high (up to 1755 mOsm kg−1) at the end of November, but this rapidly declined to c. 500 mOsm kg−1 by late December. The presence of thermal hystersis proteins was indicated by both osmometry on haemolymph samples and recrystallization inhibition studies of springtail homogenates. There was a strong relationship between glycerol content and SCP, but the relationship between haemolymph osmolality, SCP and carbohydrates is uncertain.

Fossil marine diatom assemblages from the Sørsdal Formation, a deposit of diatomaceous sand from Marine Plain in the Vestfold Hills, provide age and palaeoenvironmental information from a Pliocene coastal setting in East Antarctica. Benthic and meroplanktic diatom taxa suggest deposition in a shallow coastal embayment with water depths of 20–25 m. Diatom biostratigraphy indicates that the Sørsdal Formation belongs to the Fragilariopsis barronii Zone (4.5 to 4.1 Ma), through correlation to reference sections in the Ross Sea and Southern Ocean. Features of the other biota suggest higher sea-surface temperatures and reduced sea-ice cover, consistent with global records of higher sea level.

Major rifts is the Ross Ice Shelf controlled the October 1987 calving of the 154 × 35 km “B-9” iceberg, one of the longest on record. The 2000 km, 22 month drift of this iceberg and the quite different tracks of smaller bergs that calved with it have extended our understanding of the ocean circulation in the Ross Sea. B-9 initially moved north-west for seven months until deflected southward by a subsurface current which caused it to collide with the ice shelf in August 1988. It then completed a 100 km-radius gyre on the east-central shelf before resuming its north-westerly drift. Based upon weekly locations, derived from NOAA-10 and DMSP satellite and more frequent ARGOS data buoy positions, B-9 moved at an average speed of 2.4 km day−1 over the continental shelf. It was not grounded there at any time, but cast a large shadow of open water or reduced ice thickness during the austral winters. B-9 was captured by the continental slope current in May 1989, and attained a maximum velocity of 13 km day−1 before breaking into three pieces north of Cape Adare in early August 1989.

Gravity cores taken from five sites in the Nielsen basin, a sinuous trough on the Mac. Robertson shelf of the East Antarctic continental margin, have yielded non-marine palynofloras of late Early Jurassic to Early Cretaceous age. The palynomorphs occur in glacimarine muds and are thus not in situ, but the composition of the samples indicates that no mixing of individual assemblages has occurred, and that the sediments were deposited very close to outcrop of the source of the palynomorphs. The sequence is oldest at the seaward end of the Nielsen basin, and youngest near the fault-bounded landward end. It is interpreted as reflecting pre-break-up deposition on a passive, rifted continental margin. The age of the assemblages has been established by comparison with the zonal scheme developed in the Perth Basin of Western Australia. Similarity of the Antarctic palynofloras with those known from basins on the east coast of India confirms continental reconstructions that show this part of East Antarctica to have been contiguous with eastern India prior to break-up. The non-marine character of the palynomorphs suggests that marine conditions in this region of the Antarctic margin did not develop until at least late Early Cretaceous time.

Chert and silicified wood from the Permian through Cretaceous of Antarctica contain abundant information on fungal diversity and plant–fungal interactions. The chert deposits represent a particularly interesting setting for the study of plant–fungal interactions because they preserve remains of distinctive high latitude forest ecosystems with polar light regimes that underwent a profound climate change from icehouse to greenhouse conditions. Moreover, some of the cherts and wood show the predominance of extinct groups of seed plants (e.g. Glossopteridales, Corystospermales). Over the past 30 years, documentation of fossil fungi from Antarctica has shifted from a by-product of plant descriptive studies to a focused research effort. This paper critically reviews the published record of fungi and fungal associations and interactions in the late Palaeozoic and Mesozoic cherts and silicified wood from Antarctica; certain fungal palynomorphs and fungal remains associated with adpression fossils and cuticles are also considered. Evidence of mutualistic (mycorrhizal), parasitic and saprotrophic fungi associated with plant roots, stems, leaves and reproductive organs is presented, together with fungi occurring within the peat matrix and animal–fungus interactions. Special attention is paid to the morphology of the fungi, their systematic position and features that can be used to infer fungal nutritional modes.