Antimicrobial resistance is one of the most important global health issues identified in recent decades. Different approaches have been used to establish the presence and abundance of antimicrobial resistance genes (ARGEs) in the environment. In this study, we analysed soil samples from Fildes Peninsula (King George Island, Maritime Antarctica) exposed to human and bird impacts. The objective of the work was to identify ARGEs in the samples and to evaluate whether these genes were located in plasmids using two different strategies. A metagenomic analysis was employed to identify ARGEs according to the CARD database and to determine whether they were associated with plasmidic sequences. The analysis showed that the site exposed to high anthropogenic activity had a higher number of ARGEs compared to other sites. A large percentage of those ARGEs (19.4%) was located in plasmidic contigs. We also assessed replicon mobilization using microbial communities from these soil samples as donors through an exogenous plasmid isolation method. In this case, we could recover plasmids with ARGEs in a Tcr transconjugant clone. Although they could not be fully assembled, we could detect broad host range IncP1 and IncQ plasmid sequences. Our results indicate that sewage-impacted soils could be hotspots for the spread of ARGEs into the Antarctic environment.

Globally, the grey-headed albatross Thalassarche chrysostoma is listed as Endangered due to decreasing populations at its major breeding colonies. We analysed the population trend at Marion Island using annual counts of incubating pairs and fledglings from 1984 to 2021 and three methods: TRends and Indices for Monitoring data (TRIM), a generalized additive model and a state-space model. In contrast to rapid decreases at most other colonies, all three methods indicated a local population increase at an average annual rate of 1.3%. The latter two models indicated a decreasing trend from 1997 to 2002, presumably related to mortality on longlines set for Patagonian toothfish Dissostichus eleginoides around the island, which peaked from 1996 to 1998. Grey-headed albatrosses exhibit greater variation in annual counts than other seabird species at Marion Island, possibly linked to interannual variation in breeding success because they are biennial breeders. However, breeding success alone was not significant in any of the models, presumably because it cannot capture the complexities of both population processes and environmental variation. Although all three models predicted the overall trends well, integrated population models, which can account for demographic processes, might be more appropriate to model long-term population trends.

Silicification - the precipitation of silica within the remains of a buried organism - allows for the three-dimensional preservation of a fossil in minute cellular to subcellular detail and forms the basis for some of the most spectacular Lagerstätten for terrestrial ecosystems (e.g. Selden & Nudds 2004). Among these are the plant-bearing chert deposits of the Transantarctic Mountains, which were discovered by J.H. Mercer and J.D. Gunner during the 1969/1970 ‘Beardmore Expedition’ and sampled and first screened by J.M. Schopf soon thereafter (Schopf 1970). The collection, preparation and in-depth study of plant-bearing cherts from the Beardmore Glacier generated more than 125 publications, and systematic treatments of the permineralized biotas resulted in the description of 30 genera and almost 50 species of structurally preserved plants and fungi. The exquisite anatomical preservation enabled unusually detailed reconstruction of many of the preserved organisms, yielding the most completely known fossil members for several groups of gymnosperms (see Escapa et al. 2011). Together with similar silicified peat deposits from the remote Prince Charles Mountains in East Antarctica (McLoughlin & Drinnan 1997), these conservation-Lagerstätten of the Transantarctic Mountains constitute an extraordinary window into the biology and ecology of late Palaeozoic and early Mesozoic high-latitude terrestrial ecosystems. Perhaps the single most important of these deposits is the silicified peat from the Triassic Fremouw Formation at Fremouw Peak in the Beardmore Glacier area. Triassic silicified peat also occurs elsewhere in the Transantarctic Mountains, including the Allan Hills in southern Victoria Land (Taylor & Taylor 1990) and Timber Peak in northern Victoria Land (Bomfleur et al. 2011), but thus far the quality of preservation at other sites proved too poor to merit in-depth study.

During a 2019 Chilean Antarctic Scientific Expedition (ECA 55) studying crustose coralline algae (CCA) diversity on the Antarctic Peninsula, bleaching of these algae was observed for the first time in this region. Here, we present initial findings on the physiological state of bleached and normally pigmented CCA (Clathromorphum sp.) assessed using chlorophyll-a fluorescence induction pulse amplitude modulation. The study site experienced high light exposure and salinity in the water column. Our analyses found that bleached CCA have relatively healthy photophysiology responses but lower photosynthetic efficiency, which could be associated with the low salinities recorded in the study area. However, seasonal monitoring and mesocosm experiments across the southern polar latitudes are urgently required to confirm this hypothesis.

This study focuses on geochemical research into humic acids and humification processes in lakes of West Antarctica, specifically King George Island and Marie Byrd Land. Humic acids were extracted from recent sediments of Antarctic lakes and analysed using high-precision laboratory methods. The experiments included examining the elemental composition and molecular structure of the humic acids. The results show that the organic matter in sediments of the studied lakes has undergone complete humification processes. However, the molecular structure of humic acids is characterized by a predominance of aliphatic fragments and a significant amount of polysaccharides, which is typical of humic substances in the cold climates of Arctic and Antarctic regions. Thus, the humic substances of Antarctic lakes were found to have a very low degree of maturity and were non-resistant to mineralization. These findings are valuable for understanding the full chain of organic matter transformation processes in Antarctic ecosystems and the global carbon cycle on Earth.