Antarctic algae are extremophilic organisms capable of surviving harsh environmental conditions such as low temperatures and deep dehydration. Although these algae have various adaptations for life in extreme environments, the majority of the molecular mechanisms behind their resistance to dehydration and freezing are not yet fully understood. The aim of our research was to observe the behaviour of bound water freezing in the free-living Antarctic alga Prasiola crispa. One way to avoid frost damage involves deep dehydration of the algal thallus. For that reason, a detailed analysis of water freezing at different sample hydration levels was carried out. Nuclear magnetic resonance investigation revealed two types of water immobilization: cooperative bound water freezing for samples with sample hydration levels above Δm/m0 = 0.40 and non-cooperative bound water immobilization for lower thallus hydration levels. In the differential scanning calorimetry experiment, 2-h incubation at -20°C suggested the diffusion and final binding of supercooled water to the ice nuclei and a lower hydration level threshold, at which ice formation could be observed (Δm/m0 = 0.21). Our research provides a new perspective on water sorption and freezing in Antarctic algae, which may be important not only in biological systems, but also in such novel materials as metal-organic frameworks or covalent organic frameworks.

Analysis of conglomerates and sandstones of the Sperm Bluff Formation at the base of the Taylor Group (Devonian) between the Mackay Glacier and Bull Pass provides new insights into the nature of initial coarse-grained deposition on basement along the northern side of the McMurdo sedimentary basin. Six lithofacies are recognized in the Sperm Bluff Formation: conglomerate lithofacies, pebbly sandstone lithofacies, cross-bedded sandstone lithofacies, low-angle cross-stratified sandstone lithofacies, bioturbated sandstone lithofacies and interbedded siltstone/sandstone lithofacies. Sedimentary environments ranged from wave-dominated delta, estuary or lagoon to shoreface and inner shelf. The assemblage is thought to reflect changes in sea level. Rhyolite is the most abundant clast type in the coarse lithofacies, but is unknown in outcrop in southern Victoria Land. The rhyolites correlate in age and geochemistry with Cambrian granites in the basement. Coarse beds also contain numerous quartzite clasts, probably derived from the late Precambrian Skelton Group. Palaeocurrents on Mount Suess indicate a strong unimodal flow to the west, but other sites show polymodal palaeoflow. The Sperm Bluff Formation is correlated with Terra Cotta Siltstone, New Mountain Sandstone and Altar Mountain formations based on the lithology of sandstones and their ichnology. A northward onlap during the Early Devonian is indicated.

The region of Ridge B in central East Antarctica is one of the last unexplored parts of the continent and, at the same time, ranks among the most promising places to search for Earth's oldest ice. In January 2020, we carried out the first scientific traverse from Russia's Vostok Station to the topographical dome of Ridge B (Dome B, 3807 m above sea level, 79.02°S, 93.69°E). The glaciological programme included continuous snow-radar profiling and geodetic positioning along the traverse's route, installation of snow stakes, measurements of snow density, collection of samples for stable water isotope and chemical analyses and drilling of a 20 m firn core. The first results of the traverse show that the surface mass balance at Dome B (2.28 g cm−2 year−1) is among the lowest in Antarctica. The firn temperature below the layer of annual variations is −58.1 ± 0.2°C. A very low value of heavy water stable isotope content (-58.2‰ for oxygen-18) was discovered at a distance of 170 km from Vostok Station. This work is the first step towards a comprehensive reconnaissance study of the Ridge B area aimed at locating the best site for future deep drilling for the oldest Antarctic ice.

Plumage colour variation occurs widely among bird species and is often associated with individual fitness. More specifically, colouration can affect thermoregulatory ability, mate selection and conspicuousness during foraging. Colour aberrations can be caused by genetic mutations, dietary imbalances, environmental conditions or disease and are rare. Plumage variations have previously been noted in Adélie penguins, although without any follow-up to measure implications for behaviour or fitness. To assess how this low-frequency condition affects breeding in Adélie penguins, we monitored the breeding of several colour-aberrant Adélie penguins during the 2019–2020 nesting season at the large Cape Crozier, Ross Island colony (> 300,000 pairs). In total, we found 12 individuals with unusual plumage for a frequency of 1:50,000 breeding penguins. There were seven dark brown Adélie penguins, three progressive greying Adélie penguins, one dilute Adélie penguin and one brown Adélie penguin, of which five were female, three male and four of unknown sex. Six colour aberrants initiated breeding with a normal-coloured mate, and five raised at least one chick to crèche. The likelihood of breeding and breeding success of colour aberrants were similar to those of normal-coloured Adélie penguins, suggesting that colour aberrations do not negatively affect breeding.

Antarctica is a natural research laboratory thanks to its unique climate, geography, flora and fauna. The conservation of Antarctica's environment is monitored through the Madrid Protocol; however, there are local pollution problems associated with human activities such as research and tourism; in particular, there are negative impacts on air quality from the use of fossil fuels. In this work, we studied for the first time the magnetic and elemental characteristics of the lichen Usnea aurantiaco-atra (Jacq.) Bory collected during different years and from various sites in King George Island, Antarctic Peninsula, as well as some samples of its supporting substrate, for long-term monitoring of atmospheric pollution. Several anthropogenic elements (Ni, Pb, Mo, Cd and Zn) have been identified on sites close to human activities, but also on sites far from them. We found that magnetic proxies from U. aurantiaco-atra samples show a spatial correlation with human influence (scientific bases or airstrips). We observed a correlation between magnetic parameters and Ni and, to a lesser extent, with Cr, Co, V and Ag. The results suggest that by using these magnetic and elemental techniques it is possible to implement monitoring with the lichen U. aurantiaco-atra as a bioindicator for some elements of anthropogenic origin.

Carrion in the form of dead seal pups and algal mats placed on soft bottom habitats at Explorers Cove and Salmon Bay, McMurdo Sound, attract scavenging invertebrates that are driven away by hydrogen sulphide produced by sulphate-reducing bacteria sequestered below a layer of Beggiatoa/Thioploca-like filamentous bacteria. This system is usually found for lipid-rich marine mammal carrion, but also occurred with natural algal mats.

The present study investigates the effect of limnology on the spectral reflectance of a freshwater lake, located in an ice-free area in the Antarctic Peninsula. Field-collected samples generated limnological and spectral parameters. This fact indicates that the studied lake has an ultra-oligotrophic/oligotrophic nature based on chlorophyll a (chl a), which registered concentrations below 3 μg l-1 with no total suspended solids, almost neutral pH and transparency equalled by depth. The water spectral behaviour in each sampling station indicates that the benthic characteristics of the lake have a strong influence as the reflectance at the 705 nm wavelength being greater than that at 583 nm signals the presence of soil and/or vegetation at its bottom. Hence, it is believed that the orbital sensors with spectral bands focused on regions between the green and red edge, such as the MultiSpectral Instrument (MSI) sensor, may present better results for distinguishing the different bottom types found in the research area.

Ile de la Possession is one of the few islands in the southern Indian Ocean, making the island a valuable place to reconstruct past environmental and climatic changes. In this study a peat sediment core was analysed to reconstruct the changes that occurred before, during and after the eruption of the Morne Rouge (10 000–5500 14C yr bp) volcano. In addition to sedimentological analyses, diatom communities were used to reconstruct humidity and altitude, based on existing transfer functions. Radiocarbon dating of a tephra layer showed that the Morne Rouge volcano erupted between 6700–6600 cal. yr bp, giving a much more precise time scale for this event. The eruption was preceded by a tsunami flooding, indicated by the high numbers of marine diatoms found immediately before the tephra layer. After the eruption pioneer diatom species recolonized the coring site. Evidence is presented of the late climatic optimum around 3050 cal. yr bp, preceded by a cooling event until 6600 cal. yr bp. Nutrient input from elephant seals and wandering albatrosses obscured the climate signal for the last 600 cal yr bp.

The validity of the Antarctic species of the “Oikopleura gaussica group” (O. gaussica, O. valdiviae, O. drygalskii, and O. weddelli) is discussed. The characteristics of new material from South Georgia and the Bellingshausen Sea are compared with the original descriptions. We examined 495 specimens at different stages of maturity and concluded that the characters used to differentiate these species of Oikopleura have not enough weight to justify their separation. The morphological variations found were ascribed either to intraspecific variability and/or to the different degree of maturity of the specimens examined of a single species, Oikopleura gaussica. The main taxonomic characters for the identification of this species are: the particular way in which the flat triangular gonads surround the intestinal ball like a sheath, the equal size of the two lobes of the stomach, the oesophagus entering the postero-dorsal edge of the rounded left lobe of the stomach, the presence of oval and some times lobate oral glands, and the variable number of subchordal cells (4 to 14) arranged in a single row on the right (ventral) side of the chorda.

Bromoform concentrations in water of the slush layer that developed at the interface between snow and sea ice were measured during the seasonal warming in Lützow-Holm Bay, East Antarctica. Mean bromoform concentration was 5.5 ± 2.4 pmol l-1, which was lower than that of the under-ice water (10.9 ± 3.5 pmol l-1). Temporal decrease in bromoform concentrations and salinity with increasing temperature of the slush water suggest that the bromoform concentrations were reduced through dilution with meltwater input from the upper surface of sea ice. In contrast, bromoform concentrations in the under-ice water increased during this period while the salinity of the under-ice water decreased. It is speculated that the sea ice meltwater input contained high bromoform concentrations from the brine channels within the sea ice and from the bottom of the ice that were contributed to the increased bromoform concentrations in the under-ice water.

We describe a major shear zone exposed at Akebono Rock and discuss its deformation and metamorphic history, with a view to providing a better understanding of the geological history of the Lützow-Holm Complex. Three deformation episodes are recognized: D1 produced open folds (F1), boudinage and a regional ductile foliation, whilst the related metamorphic facies is characterized by stable garnet. F1 folding is dominantly preserved in the eastern part of the study area. During D2, an isoclinal to tight asymmetric F2 folds developed mainly in the west part of the region, accompanied by an S2 shear, under biotite facies retrograde metamorphism. The D3 episode involved the formation of the major shear zone, characterized by mylonite and L-tectonite fabrics, which took place at ~610–660°C and 4–5 kbar. Large, sigmoidal garnet core domains have S-shaped inclusion trails, suggesting that syntectonic garnet growth occurred before the formation of the shear zone. Estimated P-T conditions suggest that the sigmoidal garnet-bearing amphibolite was recrystallized at a deeper crustal level and was brought to a higher level during the formation of the shear zone. Crustal-scale deformation involving syntectonic recrystallization and shearing of Akebono Rock is a key issue for reconsidering the evolution of the Lützow-Holm Complex.

The life history and oceanic impact of three very large icebergs that escaped together from the Weddell Sea sea ice, near the tip of the Antarctic Peninsula, are traced from March 2014. Despite the initial proximity of these three icebergs, they followed very different trajectories across the South Atlantic until their eventual break-up and melting 1 year later. The largest, giant iceberg, B17a, spent extensive periods grounded near two different islands. The triplet's gradual melting is examined through the impact on the icebergs' dimensions, but also the meltwater's oceanic influence on the local salinity and primary productivity. It is found that there was generally a significant local surface and mixed-layer freshening of a few tenths of a practical salinity unit, up to several hundred kilometres away from the 10–20 km-sized icebergs. In contrast, the chlorophyll impact was highly temporally variable, although it tended to be larger in the summer. Break-up of these large icebergs did not occur until near the end of their life. We also show that modelling the trajectories of individual very large icebergs can be reasonable for up to 2 weeks if the characteristics of the iceberg and the local ocean and atmospheric forcing are well known.

A vagrant black-browed albatross Thalassarche melanophris bred with a grey-headed albatross T. chrysostoma on Marion Island at least four times between 2000 and 2009 (and continued to return to the colony until at least 2019). The eggs failed to hatch in three breeding attempts, but the pair fledged a chick in the 2006/07 breeding season. Genetic sexing identified the black-browed albatross as female and she shared all eight sampled microsatellite alleles with the chick, whereas the grey-headed albatross social parent did not match the chick. The fledgling was banded and re-sighted in its natal breeding colony in 2016 and 2018, when it displayed an intermediate black-browed x grey-headed albatross phenotype, similar to a putative hybrid photographed at sea off Australia. These results suggest that the black-browed albatross cuckolded its social mate with another grey-headed albatross in 2006/07. The failures of the other three breeding attempts at the egg stage possibly indicate genetic incompatibility with the social partner.

Environmental DNA is a powerful tool for monitoring biodiversity. Although environmental DNA surveys have successfully been implemented in various environments, protocol choice has been shown to affect results and inferences. Thus far, few method comparison studies for soil have been undertaken. Here, we optimized the workflow for soil metabarcoding through a comparative study encompassing variation in sampling strategy (individual and combined samples), DNA extraction (PowerSoil®, NucleoSpin® Soil, PowerSoil® + phosphate buffer and NucleoSpin® Soil + phosphate buffer) and library preparation (one-step and two-step quantitative polymerase chain reaction methods). Using a partial 18S rRNA marker, a total of 309 eukaryotic taxa across 21 phyla were identified from Antarctic soil from one site in the Larsemann Hills. Our optimized workflow was effective with no notable reduction in data quality for a considerable increase in time and cost efficiency. The NucleoSpin® Soil + phosphate buffer was the best-performing extraction method. Compared to similar studies in other regions, we obtained low taxonomic coverage, perhaps because of the paucity of Antarctic terrestrial organisms in genetic reference databases. Our findings provide useful methodological insights for maximizing efficiency in soil metabarcoding studies in Antarctica and other low-biomass environments.

In 2021, Brazilian scientific research in Antarctica will reach its 40 anniversary, and in that period it has experienced good and bad times. How has Brazilian scientific research evolved since its first scientific mission to Antarctica? What were the conditions that enabled this research? How will Brazilian researchers work in the brand-new scientific station? Using an interdisciplinary approach, this article identifies tipping points and the national policy network that led to unstable funding policies. This article highlights four phases of Brazilian Antarctic science and states that there is a clear disconnect between the geopolitical and scientific priorities on one side and the political priorities, including the executive and the legislative powers, on the other.

The types and distributions of anthropogenic rubbish have been documented at Bunger Hills, East Antarctica. The area has been the site of scientific research stations from 1958 to the present. Rubbish types include deliberately or negligently discarded items (gas cylinders, broken glass), abandoned unserviceable equipment (boats, vehicles, scientific equipment), spills (chemicals, fuel, oil) and the slow collapse of old buildings. Some rubbish remained where it was left, while other material was redistributed by strong winds. Modern expeditioner training should limit the production of new rubbish, while inadvertent wind dispersal of rubbish from old station buildings could be minimized by better management of these structures and their surrounds. Buildings and other constructed items need ongoing maintenance if they are not to break down and be distributed by wind, or they should be removed within a reasonable period.