Rapid and regionally contrasting climate changes have been observed around Antarctica. However, our understanding of the impact of these changes on ecosystems remains limited, and there is an urgent need to better identify habitats of Antarctic species. The Weddell seal (Leptonychotes weddellii) is a circumpolar mesopredator and an indicative species of Antarctic marine communities. It has been extensively studied in the western Ross Sea and East Antarctica, and an understanding of its ecology in the Weddell Sea in the wintertime is emerging. We documented the behavioural response(s) of four Weddell seals from February to June in 2017 in the Filchner-Ronne Ice Shelf region and related these to unusual oceanographic conditions in 2017. Unexpectedly, we found that Weddell seals had the longest foraging effort within the outflow of Ice Shelf Water or at its turbulent boundary. They also foraged on the eastern side of the trough from April to June within the Modified Warm Deep Water and seem to take advantage of the unusual conditions of persistent inflow of warm waters through the winter. Linking animal behavioural responses to oceanographic conditions is informative for quantifying rarely recorded events and provides great insight into how predators may respond to changing conditions.

Climate change in the Antarctic over the past 50+ years has caused contraction of ice and snow cover, longer melt seasons and intensified glacier melting. These changes affect erosion and sediment redistribution processes that are vital to our understanding of terrestrial and freshwater ecosystems and sediment input to oceans. This 79 day study of the Orwell Glacier meltwater stream on Signy Island (5 December 2019–21 February 2020) used 5 min recordings of turbidity, stream discharge (Q) and air temperature (AT), supplemented by 454 water samples from which suspended sediment concentration (SSC) was gravimetrically determined, to calculate daily suspended sediment loads (SSLs). Qmean was 47.8 ± 3.5 l s-1, SSCmean was 71.0 ± 15.9 mg l-1 and daily SSLmean was 75 ± 8 kg day-1 with a suspended sediment yield of 43.6 t km-2 yr-1. A multiple regression model predicted SSLs reliably (multiple r = 0.95, r2 = 0.91, n = 79) and, when run with ATmean + 1°C (expected on Signy Island by 2060) and ATmean + 2°C (expected by 2100) scenarios, the model predicted 7% and 13% increases in SSLs, respectively. The SSLs estimated in this study are low when compared with others from around the world.

The southern giant petrel (Macronectes giganteus) is a widely distributed top predator of the Southern Ocean. To define the fine-scale foraging areas and habitat use of Antarctic breeding populations, 47 southern giant petrels from Nelson Island were GPS-tracked during the summers of 2019–2020 and 2021–2022. Step-selection analysis was applied to test the effects of environmental variables on habitat selection. Visual overlap with seal haul-out sites and fishing areas was also analysed. Birds primarily used waters to the south of the colony in the Weddell and Bellingshausen seas. Females showed a broader distribution, reaching up to -70°S to the west of Nelson Island, while males were mainly concentrated in waters off the northern Antarctic Peninsula. Habitat selection of both sexes was associated with water depth and proximity to penguin colonies. Both overlapped their foraging areas with fishing sites and females in particular overlapped with toothfish fishery blocks in Antarctica and with fishing areas in the Patagonian Shelf. Due to their habitat associations and overlap with fisheries, when harnessed with tracking devices and animal-borne cameras, giant petrels can act as platforms for monitoring the condition and occurrence of penguin colonies, haul-out sites and unregulated fisheries on various temporal and spatial scales in Antarctica.

Polysulphone ultraviolet dosimetry badges were deployed daily during a British Services Antarctic Expedition to the Antarctic Peninsula, including a cruise period across the Drake Passage. The expedition was undertaken from 20 December 2011 to 7 March 2012. Badges were successfully analysed from 46 days of the expedition with a daily mean of 1.8 kJ m-2 erythemal daily dose (EDD) and a range of 0.3–4.3 kJ m-2 EDD. The results indicate that the ultraviolet EDD experienced was comparable to temperate, mid-latitude locations in the spring/late summer. The variability of the badge measurements was mostly consistent with observations from a local ground-based radiometer and equivalent satellite-derived products. However, such comparisons are limited by the changing location/altitude of the expedition and known biases in the satellite data. This highlights that the new dataset of exposure experienced at the Antarctic surface complements those produced by stationary ground-based instruments or satellites and, therefore, that the badge dataset brings a new element to this issue. The highest EDD values during the expedition occurred at high altitude, and the lowest EDD values occurred at low altitude and high latitude with relatively high total ozone column concentration.

Qualitative and quantitative analysis of surface species on size-segregated atmospheric particulate collected in Antarctica during the 2010–11 summer was performed by X-ray photoelectron spectroscopy (XPS). This represents the first example of surface characterization of Antarctic aerosols. The size class with particle cut-off diameter of 3 μm was richest in terms of chemical elements. Peculiar findings of the application included detection of Ca (possibly surface-segregated) and surface enrichment of Mg. The determination of nitrate, ammonium and sulphate species on collection filters provides evidence for a possible advantage of XPS over more laborious techniques (e.g. ion chromatography). The presence of these species is in reasonable agreement with other recent reports from Antarctica.

Within the framework of the AUSPICIO (AUtomatic Scaling of Polar Ionograms and Co-operative Ionospheric Observations) project, a limited sample of ionograms recorded mostly in 2001 and 2009, and to a lesser extent in 2006–07 and 2012–15, at the ionospheric observatories of Hobart and Macquarie Island (mid-latitude), Comandante Ferraz and Livingstone Island (high latitude), and Casey, Mawson, Davis and Scott Base (inside the Antarctic Polar Circle (APC)) were considered to study the capability of the NeQuick2 and IRI2012 models for predicting the behaviour of the ionosphere at mid- and high latitudes and over the Antarctic area. The applicability of NeQuick2 and IRI2012 was evaluated as i) climatological models taking as input the F10.7 solar activity index and ii) assimilative models ingesting the foF2 and hmF2 measurements obtained from the electron density profiles provided by the Adaptive Ionospheric Profiler (AIP). The statistical analysis results reveal that the best description of the ionosphere’s electron density is achieved when the AIP measurements are ingested into the NeQuick2 and IRI2012 models. Moreover, NeQuick2 performance is far better than IRI2012 performance outside the APC. Conversely, the IRI2012 model performs better than the NeQuick2 model inside the APC.

Blue petrels (Halobaena caerulea Gmelin) rapidly moult their flight feathers in Antarctic waters in February–April, immediately following the breeding season, yet the behaviour of moulting birds at sea has not been described. We observed large numbers of moulting blue petrels off West Antarctica from 67–71°S and 78–119°W in mid-February 2017. Most of these birds probably breed at the Diego Ramirez archipelago, southwest of Cape Horn, which is the closest colony to this area. Moulting petrels often sit on the water in dense flocks, just outside the marginal ice zone, at sea temperatures of -0.7 to 0.9°C. Wing moult is intense, with 7–8 inner primaries (62–75% of primary length and 55–69% of primary mass), their corresponding primary coverts and all greater secondary coverts being grown at the same time. Moulting petrels need a reliable food source during this energetically demanding period, so the waters off West Antarctica are probably crucial for the Diego Ramirez population, which makes up more than half of the world's blue petrels.

Glacial melt has a great influence on biological communities of the Antarctic Peninsula. Annual changes in heterotrophic flagellates from March 2008–March 2009 and effects of glacial melting on heterotrophic flagellates from December 2008–March 2009 were studied within the coastal zone of King George Island. The maximum abundance and biomass occurred in November and December (950.6–1236.2 individuals ml-1; 0.02–0.035 μg C ml-1), and the minimum in May and June (419.8–456.8 individuals ml-1; 0.018–0.019 μg C ml-1). Forty-five species were identified. The diversity of choanoflagellates, euglenids, bicosoecids, kinetoplastids and incertae sedis flagellates was greatest. Glacial melt between December and April resulted in the freshening of the surface water at the Collins Bay, giving rise to a vertical gradient of salinity (from 26‰ at the surface to 34‰ at the near-bottom layer). The trophic, size and species structure of the heterotrophic flagellates was simplified due to freshening of the surface waters. Eurybiontic and cosmopolitan species were significantly enriched in the freshened surface layer, with prevalence of small-sized mobile bacterio-detritovorous forms. The simplification of structure of the assemblage of heterotrophic flagellates can affect the stability of biological communities.

The boundary layer thermal structure, observed through Doppler sodar, at Dumont d'Urville, has been analysed. Typical echograms of the spiky layers, wavy layers and thermal plumes, except for the eroding inversion, have been observed. The annual distribution of these thermal structures is presented. The spiky layers are observed to coincide with strong winds (mainly katabatic) flowing from the inner continent sector, 90°–180°. The upper boundary of the spiky layers is correlated to the wind direction; the maximum depths (more than 400 m) are confined to 60° wide span centred at 135°. The predominant waves and the spiky layers, tend to occur alternately in accordance with the relative dominance of the katabatic flow intensity and the stability conditions. The sodar signatures of these structures are examined in relation to the onset and dissipation time, duration and the seasonal distribution. Both waves and spiky layers occur at any hour of the day; their maximum occurrence is in winter months. The persistence of the waves varies from a couple of hours to a couple of days while the spiky layers can occur for periods even longer than 3–4 days. The characteristics of these phenomena are associated with the diurnal radiational cycle and the temperature contrast in proximity to the coast.

The consumption of food by the four species of breeding penguins at the Prince Edward Islands is assessed on an annual and seasonal basis. Total annual food consumption was estimated at 880 000 t, of which king penguins accounted for 74%, macaroni penguins 21%, rockhopper penguins 5% and gentoo penguins <1%. Pelagic fish, almost entirely myctophids, were the most important prey (70% of total prey biomass), followed by pelagic crustaceans (18%) and cephalopods (11%). Demersal fish and benthic crustaceans accounted for <1% of total consumption, being consumed only by gentoo penguins. Peak demands of between 2 and 3.3 × 106 kg d−1 occurred from October–December when three of the four species were breeding, including the two demi-populations of king penguins. Food demand decreased to 1.2 × 106 kg d−1 during winter when only king and gentoo penguins were present. Much of the prey are presumably captured within 300 km of the islands. Assuming an even distribution of foraging effort within their respective foraging ranges, rates of food transferred to penguins in November ranged from 4.1 × 10−3 g m−2 d−1 for macaroni penguins to 1.24 × 10−2 g m−2 d−1 for king penguins. In mid-July, transfer rates to king and gentoo penguins were 3.9 × 10−3 g m−2 d−1 and 6.7 × 10−3 g m−2 d−1, respectively. The importance of pelagic myctophid fish to penguin populations at the Prince Edward Islands is clear.

The performance of the UK Meteorological Office operational numerical weather prediction system in the Antarctic is examined. The analysis/forecast model currently has a reasonable representation of the atmospheric circulation, although there are some problems. During the first three days of the forecasts the katabatic winds in the coastal region become too strong compared to those in the initial fields, which results in coastal easterly winds that are too strong. However, the pattern of katabatic winds across the continent is broadly correct, suggesting that there are no major errors in the model orography used. The forecast tropospheric temperatures are generally too cold, although positive errors are found inland of the coast in the region of descent associated with the katabatic wind circulation. The mean forecast low pressure centres within the circumpolar trough are in approximately the correct locations, although the depth of the centres is too deep. During January there is good agreement between the model total cloud amount over the Antarctic and the estimates of total cloud cover from in situ observations. However, in July the model has too much cloud. There is no significant change in the amount of cloud during the first three days of the forecasts. The model has a good representation of the broadscale field of snow accumulation across the Antarctic. A comparison of various 6 hour forecast model fields against observations confirms the errors noted in the three-day forecasts when compared against analyses

Stange Ice Shelf is the most south-westerly ice shelf on the Antarctic Peninsula, a region where positive trends in atmospheric and oceanic temperatures have been recently documented. In this paper, we use a range of remotely sensed datasets to evaluate the structural and dynamic responses of Stange Ice Shelf to these environmental changes. Ice shelf extent and surface structures were examined at regular intervals from optical and radar satellite imagery between 1973 and 2011. Surface speeds were estimated in 1989, 2004 and 2010 by tracking surface features in successive satellite images. Surface elevation change was estimated using radar altimetry data acquired between 1992 and 2008 by the European Remote Sensing Satellite (ERS) -1, -2 and Envisat. The mean number of surface melt days was estimated using the intensity of backscatter from Envisat’s Advanced Synthetic Aperture Radar instrument between 2006 and 2012. These results show significant shear fracturing in the southern portion of the ice shelf linked to enhanced flow speed as a consequence of measured thinning. However, we conclude that, despite the observed changes, Stange Ice Shelf is currently stable.

High temporal resolution (three hours) records of temperature, wind speed and sea level pressure recorded at Antarctic research station Neumayer (70°S, 8°W) during 1982–2011 are analysed to identify oscillations from daily to intraseasonal timescales. The diurnal cycle dominates the three-hourly time series of temperature during the Antarctic summer and is almost absent during winter. In contrast, the three-hourly time series of wind speed and sea level pressure show a weak diurnal cycle. The dominant pattern of the intraseasonal variability of these quantities, which captures the out-of-phase variation of temperature and wind speed with sea level pressure, shows enhanced variability at timescales of ∼ 40 days and ∼ 80 days, respectively. Correlation and composite analysis reveal that these oscillations may be related to tropical intraseasonal oscillations via large-scale eastward propagating atmospheric circulation wave-trains. The second pattern of intraseasonal variability, which captures in-phase variations of temperature, wind and sea level pressure, shows enhanced variability at timescales of ∼ 35, ∼ 60 and ∼ 120 days. These oscillations are attributed to the Southern Annular Mode/Antarctic Oscillation (SAM/AAO) which shows enhanced variability at these timescales. We argue that intraseasonal oscillations of tropical climate and SAM/AAO are related to distinct patterns of climate variables measured at Neumayer.

Echinozone quadrispinosa (Beddard, 1886) is reduced to synonymy with E. spicata (Hodgson, 1910). A key is given to the four Antarctic species together with biogeographical information.

During fieldwork of the 1998–99 and 1999–2000 Chinese National Antarctic Research Expedition (CHINARE), three different kinds of Cenozoic sedimentary record were found in the Grove Mountains, which are in East Antarctica about 450km inland of Prydz Bay. These consist of (1) glaciogenic sedimentary erratics found in the moraine banks in the central area of Grove Mountains, which can be subdivided into four types according to different degrees of lithification as well as differences in inner structure and include in-situ diamicts; (2) palaeosols found in several small depressions in the southern slope of the Mount Harding; and (3) different kinds of glacial moraine floating on the surface of blue ice or around the foot of some nunataks. Preliminary results suggest that the in situ glaciogenic sediments were formed in the ice-sheet frontal area by the interaction of glacial movement and ice sheet melt water under climatic conditions warmer than today.

We comment on the conjecture by Parker et al. (2016) that Antarctic toothfish recently returned to McMurdo Sound, arguing that this species never departed. Instead, as deduced from a 40-year fishing effort, toothfish water column prevalence became markedly reduced where bottom depths are <500 m, with research continuing to show their presence on the bottom or above the bottom where depths are deeper. We also counter arguments that toothfish departed, and remained absent, during and following a five-year presence of mega-icebergs residing near the opposite coast of Ross Island, the icebergs inhibiting or fomenting conditions that discouraged toothfish presence in the Sound. Available analyses reveal that toothfish movement into the Sound was probably not significantly affected, and additionally that neither changes in hydrography nor in primary productivity in the Sound would have been sufficient to impact toothfish presence through food web alteration. We hypothesize that the local effect of predation by seals and whales and the regional effect of a fishery targeting the largest toothfish (those neutrally buoyant and thus capable of occupying upper levels of the water column) has resulted in the remaining toothfish now being found predominantly closer to the bottom at greater depths.

This paper summarizes fieldwork conducted in 2007 and presents results of petrographical analyses of basement rocks that occur along with fossil-rich Eocene sedimentary erratics in moraines along the north-east flank of Mount Discovery in southern McMurdo Sound. The Eocene rocks are significant as they provide a rare glimpse into greenhouse environments at high southern latitudes. Basement erratics recovered from the moraines are petrographically similar to metamorphic and igneous rocks exposed in the Transantarctic Mountains at locations between the Carlyon and Skelton glaciers and/or within the drainage catchments of Mulock and Skelton glaciers. These new clast provenance data imply that the Eocene sedimentary erratics are most likely derived from outcrops that are currently located beneath the Ross Ice Shelf south and/or immediately east of Minna Bluff. The suite of basement and sedimentary erratics were transported to their present location by ice that flowed north-eastwards from the Skelton-Mulock region and was pushed westwards into southern McMurdo Sound by grounded ice flowing north from West Antarctica. Results from this study support prior reconstructions of ice flow during peak glacial intervals during the Miocene–Pleistocene including the Last Glacial Maximum.

The clarity of 39 meltwater ponds on the McMurdo Ice Shelf was determined as the horizontal viewing range of a black disc. Visual ranges varied widely from pond to pond from 0.14–5 m; so did the concentrations of optically-active constituents, including the suspended particulates, phytoplankton (10-fold variation) and inorganic suspensoids (> 100-fold), and dissolved yellow substance (10-fold). In six of the ponds the ratio of beam attenuation coefficient to total suspended solids concentration was low (< 0.6 m2 g−1) compared to that in the others (0.7–2.0 m2 g−1, suggesting that generally larger particles were present suspended in the water in these ponds. In both groups, relationships between beam attenuation and constituent concentrations indicated that much of the attenuation was due to inorganic suspensoids. Organic detritus also appeared to be important in many ponds, while phytoplankton and dissolved yellow substance were generally less important. Even though the clarity of many of the ponds was poor, their relative shallowness meant levels of underwater light were probably generally adequate for benthic plant growth.