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.

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.

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.

Sea ice is the major constraint on human activities in the Southern Ocean. Depending on a vessel's ice class, human mobility may be restricted or even prevented altogether by sea-ice conditions. This may imply limited access to research or monitoring stations, preferred fishing grounds or attractive tourist sites. Here, we introduce a statistical model that evaluates the sea-ice cover with two measures: 1) accessibility (i.e. the probability that a given area is navigable by vessels at a given time) and 2) repeated accessibility (i.e. the probability that a given area is navigable by vessels at a given time and again at least once within a defined timespan). We use daily sea-ice concentration data from 2002 to 2020 to demonstrate this tool and its functioning regarding the spatiotemporal variability of sea-ice cover in the wider Weddell Sea region. These findings reflect known characteristics of sea-ice distribution and dynamics in the Weddell Sea, confirming the functionality of our simple tool for determining repeated accessibility of certain areas. Such a tool may facilitate the planning of research and monitoring activities in the Southern Ocean, as well as in Arctic seas.

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.

The Antarctic Peninsula is undergoing rapid change due to global warming, including air and water temperature increases. Fauna inhabiting the intertidal zone are particularly exposed to warming impacts, as they are subjected to high variations in both terrestrial and marine environmental settings. This study aimed to assess intertidal macrofaunal and meiofaunal biodiversity, tidal height-related assemblage structural patterns and their responses to variability in environmental parameters on King George Island. A total of 39 macrofaunal taxa were identified, with polychaetes and amphipods being the most diverse groups and gastropods, amphipods and bivalves being the most abundant. In the case of meiofauna, 16 taxa were found, mainly nematodes, copepod nauplii and harpacticoids. There was a significant decrease in the number of species, abundance and biomass for both macrofauna and meiofauna with increasing tidal height. Our investigation documented highly diverse and abundant fauna in the Antarctic intertidal zone. With its thriving life, it could serve as a perfect model system for detecting climate change impacts on local biodiversity. Therefore, we propose the Antarctic intertidal zone as a suitable habitat for monitoring these changes.

Predictions of the future emperor penguins population, linked to anthropogenic climate change, are stark. Current models suggest that if CO2 emissions continue to rise at present rates, almost all colonies will be quasi-extinct by the end of the century (Jenouvrier et al. 2021). The monitoring of populations is crucial to tracking these changes and, if possible, implementing conservation measures. Recent work using satellite imagery to discover, track and monitor emperor penguin populations has proved to be a key technology in understanding the locations, numbers and trends of the species (Barbraud & Weimerskirch 2001, Trathan et al. 2020, Jenouvrier et al. 2021). It also enables the discovery of unrecorded breeding sites (Fretwell et al. 2009), although there are inherent difficulties in determining what constitutes a new or undiscovered breeding colony (see Supplemental Material S1). In 2019, eight previously unreported emperor penguin breeding sites were found using the European Space Agency's Sentinel-2 satellite, a medium-resolution satellite with a spatial resolution of 10 m per pixel (Fretwell & Trathan 2021), bringing the number of known extant breeding locations to 61. Here, I report on the discovery of a further four breeding sites using Sentinel-2 and Maxar WorldView-2 imagery.

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.

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.

The life history traits of bathydraconids, deep-living fishes distributed all around the Antarctic continent, are poorly known. In particular, very few data are available on the relatively rare genera Akarotaxis and Bathydraco. With the aim to fill this gap, sagittal otoliths and gonads were analysed to assess individual age and reproductive features of Akarotaxis nudiceps (Waite, 1916), Bathydraco macrolepis Boulenger 1907 and Bathydraco marri Norman, 1938 collected in the Weddell Sea. Based on the annual growth increment patterns, age estimates ranged between 6–11, 5–11 and 8–11 years for A. nudiceps, B. macrolepis and B. marri, respectively. Most of the gametogenetic processes could be described based on gonad histology for both sexes. Females shared the reproductive features commonly reported in notothenioids, such as group-synchronous ovary development and prolonged gametogenesis. Total fecundity estimates were comparable between the two species of Bathydraco (1500–2500 eggs/female), whereas that of Akarotaxis was one order of magnitude smaller (200–250 eggs/female). Consistently, the mean size of late vitellogenic oocytes showed an opposite trend, being 1.6–1.8 mm in Bathydraco and 2.2 mm in Akarotaxis.

Antarctic krill are the dominant metazoan in the Southern Ocean in terms of biomass; however, their wide and patchy distribution means that estimates of their biomass are still uncertain. Most currently employed methods do not sample the upper surface layers, yet historical records indicate that large surface swarms can change the water colour. Ocean colour satellites are able to measure the surface ocean synoptically and should theoretically provide a means for detecting and measuring surface krill swarms. Before we can assess the feasibility of remote detection, more must be known about the reflectance spectra of krill. Here, we measure the reflectance spectral signature of Antarctic krill collected in situ from the Scotia Sea and compare it to that of in situ water. Using a spectroradiometer, we measure a strong absorption feature between 500 and 550 nm, which corresponds to the pigment astaxanthin, and high reflectance in the 600–700 nm range due to the krill's red colouration. We find that the spectra of seawater containing krill is significantly different from seawater only. We conclude that it is tractable to detect high-density swarms of krill remotely using platforms such as optical satellites and unmanned aerial vehicles, and further steps to carry out ground-truthing campaigns are now warranted.

In order to reconstruct past environmental conditions along the north-eastern Antarctic Peninsula, we documented changes in grain size, grain roundness, onlap as seen in ground-penetrating radar reflection profiles and ice-rafted debris on a set of 36 raised beaches developed over the last ~7.7 ± 0.9 ka on Joinville Island. The most pronounced changes in beach character occur at ~2.7–3.0 ka. At this time, there appears to have been a reintroduction of less rounded material, the development of stratification within individual beach ridges, an introduction of seaweed and limpets to the beach deposits, a change in clast provenance (although slightly earlier than the change in cobble roundness) and a shallowing of the overall beach plain slope. Prolonged cooling associated with the Neoglacial period may have contributed to these changes, as the readvance of glaciers could have changed the provenance of the beach deposits and introduced more material, leading to the change in roundness of the beach cobbles and the overall slope of the beach plain. This study suggests that late Holocene environmental change left a measurable impact on the coastal zone of Antarctica.

Sulphide-bearing quartz veins were first observed on Hurd Peninsula, Livingston Island, at Henry Bluff in 1958 (Hobbs 1968). Subsequent mapping of the host Miers Bluff Formation (MBF) in western Hurd Peninsula either did not record veining or was ambiguous as to its distribution, scale of development and genesis (for review see Pride et al. 1990).

Ozone concentrations in the atmospheric surface layer above the Weddell Sea during the Antarctic spring season of 1989 varied significantly. Lower levels of ozone were associated with colder Antarctic air masses and higher values with warmer mid-latitude air. The lowest ozone concentration (1 to 2 ppbv) was measured in the centre of a low pressure system. A definite diurnal variation of tropospheric ozone observed during clear days with low total ozone amount (177 matm cm) may be interpreted as a consequence of the occurrence of photochemical reactions under conditions of increased ultraviolet solar radiation.

Because of the lack of a definitive air link to an international gravity base station, the Antarctic Peninsula gravity network was originally, and still is, tied to the Potsdam gravity system via long ship links to South America (Renner 1981, Kennett 1965). An indirect link from the British Antarctic Survey (BAS) scientific station at Rothera to an International Gravity Standardisation Net 1971 (IGSN 71) base station in the UK had previously been made via a link to the BAS gravity station on the Falkland Islands in Port Stanley (McGibbon 1988). Whilst the apparent gravity difference between Port Stanley and the base station in the UK had been calculated via a two-way air tie using a LaCoste and Romberg meter (McGibbon 1988) and later strengthened with three two-way air ties using four LaCoste and Romberg meters (Bassett 1987), the link between Port Stanley and Rothera was based on a one-way tie that included a lengthy ship borne passage (McGibbon 1988). The weakness of this link insured that the adopted gravity value at Rothera continued to be based on the ship ties made by Griffiths et al. (1964) and Kennett (1965). This note describes the strengthening of the gravity link between Rothera and Port Stanley and the subsequent reassignment of the adopted gravity value at Rothera Station.

Air temperature lapse rates vary geographically and temporally. Sub-Antarctic Macquarie Island provides an opportunity to compare lapse rates between windward and leeward slopes in a hyper-oceanic climate. Lapse rates were steep by global standards, typically close to the dry adiabatic lapse rate despite the near-constant high humidity. Limited diurnal and seasonal variation occurs in lapse rates on Macquarie Island. High variability of lapse rates on the eastern (lee) slope in summer months and in the midday hours appears to be driven by solar radiation. No diurnal or seasonal pattern was evident on the western slope. Development of orographic cloud is expected to modify lapse rates, given the theoretical shift between dry and saturated adiabatic lapse rates that occurs with condensation of water vapour. Cloud cover was frequent, with higher elevations being under cloud 50% of the time, with no seasonal variation. However, cloud base level did not explain variation in lapse rates. Low cloud is likely to be of ecological importance because it influences fog precipitation, solar radiation and evapotranspiration. Year-round dominance of westerly airflows and limited seasonal variation in air temperature and humidity explain the limited seasonal variation in cloud cover and lapse rates on Macquarie Island.

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.

Growth, which is intrinsically linked to environmental conditions including temperature and food availability are highly variable both temporally and spatially. Estimates of growth rates of the Southern Ocean euphausiid Thysanoessa macrura are currently restricted to limited studies which rely upon repeated sampling and length-frequency analysis to quantify growth rates. The instantaneous growth method (IGR) was used to measure the growth rate of T. macrura successfully in the southern Kerulen Plateau region during summer, providing the first IGR parameters for the Southern Ocean euphausiid species. Results of the four-day IGR incubation indicate a period of low somatic growth for adult T. macrura. Males had a longer intermoult period (IMP) (62 days) than females (42 days), but the sexes exhibited similar daily growth rates of 0.011 mm day−1 and 0.012 mm day−1 respectively. Juveniles exhibited the fastest growth, with an IMP of 13 days and daily growth rate of 0.055 mm day−1 indicating a prolonged growth season, similar to the Antarctic krill E. superba. Consequently, we highlight the usability of the IGR method and strongly encourage its use in developing a comprehensive understanding of spatial and seasonal growth patterns of T. macrura.