Zoophycos is a complex three dimensional trace fossil that is abundant in deep ocean sediments worldwide, but has not been described previously from Cenozoic continental margin deposits of Antarctica. In the ANDRILL 1B core drilled through the north-west McMurdo ice shelf, Zoophycos occurs in a 17 m thick unit of interglacial sediments bounded above and below by glacial surfaces of erosion. This unit was deposited during the transition from the relatively warm Early Pliocene characterized by productive open waters to the cooler Late Pliocene with fluctuating subpolar ice sheets. Globally, Late Cenozoic Zoophycos are most abundant at great depths (> 1000 m), and where sedimentation rates and TOC levels are low; the Zoophycos producer, probably a worm-like animal, was (is) a slow colonizer. Application of these preferences to the ANDRILL 1B core indicates that the Zoophycos-bearing unit was deposited episodically, with sufficient time between events to allow for the slow processes of colonization and construction. The foray of Zoophycos producer into the relatively shallow ANDRILL 1B depths (200–1000 m) during the Pliocene documents “emergence” of benthic animals, supporting suggestions that the unique modern Antarctic and Southern Ocean faunas result from both “emergence” and “submergence” during the Cenozoic.

Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

The harsh climatic conditions and low levels of human activity in Antarctica, relative to other regions, means few non-native species have established. However, the risk of introductions is becoming greater as human activity increases. Non-native microorganisms can be imported to Antarctica in association with fresh food, cargo and personal clothing, but the likelihood of their establishment is not well understood. In January 2015, a wooden packing crate, heavily contaminated with fungi, was imported by aircraft from Punta Arenas, Chile, to Rothera Research Station, Antarctica. Mucor racemosus Bull. and two strains of Trichoderma viridescens (A.S. Horne & H.S. Will.) Jaklitsch & Samuels were isolated from the wood. Measurements of hyphal extension rates indicated that all three strains were psychrotolerant and capable of growth at 4°C, with M. racemosus growing at 0°C. The imported fungi could grow at rates equivalent to, or faster than, species isolated from Antarctic soils, suggesting that low temperature may not be a limiting factor for establishment. It is recommended that wood heat-treatment standards, equivalent to those described in the International Standards for Phytosanitary Measures No. 15, are employed by national operators importing cargo into Antarctica, and that treated wood is adequately stored to prevent fungal contamination prior to transportation.

Deschampsia antarctica Desv. (Poaceae) grows in coastal habitats in the Maritime Antarctic where it is often exposed to sea spray. Salt crystals have been observed on the surface of leaves in plants treated with high NaCl. We investigated if D. antarctica is a salt tolerant species that allows sodium ions to diffuse into the root where a salt overly sensitive (SOS) system extrudes Na+ from root cells and facilitates its movement through the xylem up to the leaves. Leaf epidermis, physiological parameters and sodium transporters in D. antarctica plants exposed to NaCl were studied over 21 days. Epidermal scanning electron microscopy showed trichome induction in the leaves of salt treated plants. In addition, salt treated plants showed increased sodium and proline levels with a concomitant increased expression of SOS genes (1 and 3). These results indicate that Na+ is taken up by the roots of D. antarctica and transported to the leaves. The sodium flux may be controlled by SOS1 activity. Up-regulation of the SOS1 gene may be involved in the increased sodium levels observed in the leaves of salt treated plants. Trichomes may also be involved in sodium exudation through the leaves under saline conditions.

A small, inconspicuous lichen, Acarospora cf. badiofusca, was discovered colonizing iron-stained quartz mica schists on the lower slope of Manhaul Rock, a recently exposed nunatak on the McLeod Glacier, Signy Island, South Orkney Islands. Thallus colour ranged from rust on exposed rock surfaces to paler orange and green in shaded crevices. This study addressed the hypothesis that colour reflects element localization, and considered substance localization within lichen tissues and responses to stress. Electron microprobe analysis of specimens confirmed that Fe is localized principally in the outer rust-coloured part of the cortex, confirming that the colour reflects Fe localization. Oxalates, widely reported as contributing to tolerance mechanisms to environmental stress, were not detected using X-ray diffraction. The upper thallus surface consisted of sub-micron particulate phases containing Fe, Al and O, suggesting mixed oxide/hydroxide phases are present and play a role in photoprotection.

Coastal polynyas, which form around the Antarctic coast due to persistent katabatic winds, play an important role in enhancing air-sea interaction. This paper discusses how thermal imagery from the Advanced Very High Resolution Radiometer (AVHRR) can be used to track the direction of katabatic winds, and hence facilitate research into air-sea interaction.

A new xanthid crab, Tumidocarcinus foersteri n. sp. is described from the La Meseta Formation on Seymour Island, Antarctica. The fossils were obtained from the Allomember Submeseta of Late Eocene age. As other representatives of the genus Tumidocarcinus were only known from New Zealand and Australia, this finding provides new insights on the palaeobiogeography of high latitude faunas during the Early Tertiary.

Marine-geophysical evidence on sea-floor morphology and shallow acoustic stratigraphy are used to examine the substrate around the location at which Sir Ernest Shackleton's ship Endurance sank in 1915 and on the continental slope-shelf sedimentary system above this site in the western Weddell Sea. Few signs of turbidity-current and mass-wasting activity are found near or upslope of the wreck site, and any such activity was probably linked to full-glacial higher-energy conditions when ice last advanced across the continental shelf. The wreck is well below the maximum depth of iceberg keels and will not have been damaged by ice-keel ploughing. The wreck has probably been draped by only a few centimetres of fine-grained sediment since it sank in 1915. Severe modern sea-ice conditions hamper access to the wreck site. Accessing and investigating the wreck of Endurance in the Weddell Sea therefore represents a significant challenge. An ice-breaking research vessel is required, and even this would not guarantee that the site could be reached. Heavy sea-ice cover at the wreck site, similar to that encountered by Agulhus II during the Weddell Sea Expedition 2019, would also make the launch and recovery of autonomous underwater vehicles and remotely operated vehicles deployed to investigate the Endurance wreck problematic.

Six species of anascan cheilostome Bryozoa are described from Antarctica. Apiophragma gen.nov. is introduced for Megapora hyalina Waters, 1904. Cellaria dennanti Waters, 1904 non MacGillivray, 1895 is redescribed as Swanomia belgica sp.nov. Paramawsonia Androsova, 1972 is restricted to its type species, Cellaria dennanti MacGillivray, 1985. Micropora notialis sp.nov. is distinguished from M. brevissima Waters, 1904. Two new species are described in the genus Cellaria.

Several historical sea level time series from Antarctic tide gauges, available from the Permanent Service for Mean Sea Level, are analysed. Two sea level curves, obtained by averaging data from the Antarctic Peninsula and West Antarctica, for 1958–2014, show trends of (2.0±0.1) and (1.8±0.2) mm yr-1, respectively. By empirical mode decomposition, cyclic and non-cyclic components of sea level change were separated. A periodicity of 4–5 years was confirmed and attributed to the effects of the Antarctic Circumpolar Wave. The non-cyclic components were found to show a ‘levelling off’ of ≈ 1 mm yr-1 since c. 2000, which cannot be attributed to the isostatic response to Holocene ice melting. Using assessed mass balance data from the West Antarctic Ice Sheet and the Antarctic Peninsula, we studied the response to current ice loss in the region and found that the levelling off could be partly explained by accelerated melting during the last approximately two decades. This may represent the first evidence of sea level fingerprints of glacial melting in Antarctica.

During January and February 2004, data on presence and distribution of killer whales (Orcinus orca) and other cetaceans were collected by helicopter surveys along the coastline of Terra Nova Bay and adjacent localities (western Ross Sea, Antarctica). A total of 37 sightings of killer whale, of both B and C types, were recorded as well as 17 sightings of Antarctic minke whales (Balaenoptera bonaerensis), nine of Balaenoptera spp., two of Arnoux’s beaked whale (Berardius arnuxii) and four of undetermined species. The type C killer whale was the most abundant, with 23 sightings, whereas we recorded type B only twice. Group size ranged between 1 and 30 animals, with an average of eight individuals. Seventeen killer whales were photo-identified and 13 resightings occurred during the study period. Killer whales showed a differential pattern in partitioning the study area. Their encounter rate was significantly higher (t-test = 2.6045, P < 0.05) in the northern area extending from Edmonson Point to the Campbell Glacier Tongue (encounter rate, ER = 0.031), compared to the southern area from Mario Zucchelli Station to the Drygalski Ice Tongue (ER = 0.003).

We present an analysis of the 20 year snowfall dataset in Taylor Valley and the results of a new snow cover monitoring study. Snowfall has been measured at four sites in Taylor Valley from 1995 to 2017. We focus on valley-floor snowfall when wind does not exceed 5 m s-1, and we exclude winter from our analysis due to poor data quality. Snowfall averaged 11 mm water equivalent (w.e.) from 1995 to 2017 across all stations and ranged from 1 to 58 mm w.e. Standard deviations ranged from 3 to 17 mm w.e., highlighting the strong interannual variability of snowfall in Taylor Valley. During spring and autumn there is a spatial gradient in snowfall such that the coast received twice as much snowfall as more central and inland stations. We identified a changepoint in 2007 from increasing snowfall (3 mm w.e. yr-1) to decreasing snowfall (1 mm w.e. yr-1), which coincides with a shift from decreasing temperature to no detectable temperature trend. Daily camera imagery from 2007 to 2017 augments the snowfall measurements. The camera imagery revealed a near tripling of the average number of days with snow cover from 37 days between 2006 and 2012 to 106 days with snow cover between 2012 and 2017.

Geophysical, structural, geomorphological, topographical and bathymetric data from the Hurd Peninsula area, Livingston Island, South Shetland archipelago, suggest that an extensional fault system, orientated NW–SE, together with a conjugate group of NE–SW normal oblique-slip faults, control the landforms in this area. These structures separate fault-bounded blocks of different heights, giving rise to a horstgraben structure. The depressed blocks were filled by glaciers and flooded in part by the sea. The recent movement of these faults can be established from the calculated isopachs of a small Quaternary sedimentary basin, related to this extensional fault system, which shows that sedimentary bed thickness is controlled mainly by the NE–SW fault system. Geomorphological analysis also shows that the NW–SE faults control the main morphostructures of this region. The character of the recent stress tensor has been established from fault-slip data, taking into account only those faults that are related to morphostructures. The calculated palaeostress tensor is extensional, with a N46°E main extension direction, and an average stress ratio of 0.17.

The COVID-19 pandemic and pandemic-related measures have impacted the lives and work-related activities of Antarctic researchers. To explore these impacts, we designed, piloted and disseminated an online survey in English, Russian, Spanish and Chinese in late 2020 and early 2021. The survey explored how the pandemic affected the productivity of Antarctic researchers, their career prospects and their mental wellbeing. Findings exposed patterns of inequities. For instance, of the 406 unique responses to the survey, women appeared to have been affected more adversely than men, especially in relation to mental health, and early-career researchers were disadvantaged more than their mid- or late-career colleagues. Overall, a third of the research participants reported at least one major negative impact from the pandemic on their mental health. Approximately half of the participants also mentioned that the COVID-19 pandemic had some positive effects, especially in terms of the advantages that working from home brought and opportunities to attend events, network or benefit from training workshops online. We conclude with a series of recommendations for science administrators and policymakers to mitigate the most serious adverse impacts of the pandemic on Antarctic research communities, with implications for other contexts where scientific activities are conducted under extreme circumstances.

A moderately diverse assemblage of plant microfossils has been recovered from the Johnsons Dock Member of the Miers Bluff Formation, Livingston Island, including spores, pollen, acritarchs, wood fragments and cuticles. Containing a total of c. 45 of miospore taxa, the palynoflora is dominated by non-striate bisaccate pollen, but spores of pteridophytes and pollen of gymnosperms are proportionate in diversity. The palynoflora is similar in composition to those indicative of subzones C + D of the Alisporites Zone of Antarctica, and the upper Craterisporites rotundus Zone and the lower Polycingulatisporites crenulatus Zone of Australia as well as the upper Polycingulatisporites crenulatus Zone and Foveosporites moretonensis Zone of New Zealand, suggesting a Late Triassic (possibly Norian–Rhaetian) age. This determination is supported by the sporadic occurrence of Aratrisporites and Classopollis in the palynoflora as well as by the absence of striate bisaccate grains.

Krill consumption by natural predators represents a critical link between surveys and models of standing krill biomass and the design of a sustainable krill fishery for the Scotia Sea. Antarctic krill (Euphausia superba) is a significant component of diet for penguins breeding in this region and, consequently, uncertainties regarding penguin population abundances contribute to uncertainties in krill predation estimates. We use a comprehensive database of Antarctic penguin abundances to identify 14 breeding colonies that contribute most significantly to uncertainty regarding the total number of pygoscelid penguins breeding in this region. We find that a high quality survey of Zavodovski Island alone would decrease uncertainty in total population by 24.8%, whereas high quality surveys of all 14 “high-influence” locations would decrease uncertainty by almost 72%. Updated population estimates at these sites should be considered top priority for future fieldwork in the region. Our results are based on a robust quantitative method for assessing data priorities in estimating krill consumption that is easily extended to other groups of krill predators.

The polar cusp ionosphere is an important part of near-Earth space which is best monitored by ground-based observations made in the remote polar regions. Antarctica seems certain to play a key role in its future exploration. The region is characterized by the direct entry of solar wind particles along magnetic field lines projecting to the dayside magnetopause (outer boundary of the magnetosphere). Thus the polar cusp ionosphere provides a splendid window for examining processes transferring solar wind mass and momentum to the magnetosphere. The review will emphasize this aspect of polar cusp ionosphere research, an area where the pace of recent work has been rapid. New results highlight the relevance of both the interplanetary magnetic field direction and changes in solar wind pressure for dynamic effects in the polar cusp ionosphere. These phenomena include surges in plasma flow, auroral activity, magnetic impulses and field-aligned (Birkeland) currents. Among the theoretical advances emerging just this past year are ones for the origin of plasma transport in the dayside polar ionosphere and for the source of the dayside Region 1 and cusp Birkeland currents.