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.

We report on the pore size distribution and water retention of Beacon sandstone from Antarctica that harbours a cryptoendolithic community, predominantly lichens, just below the surface. We measured the pore size distribution, drying time and equilibrium relative humidity of sandstone samples that were colonized by lichens. The incremental pore volume distribution peaks at ~10 μm radius, but ~20% of the pore volume occurs for a radius < 0.02 μm. Water from snowmelt fills ~20% of the total pore volume. It takes ~4–5 days of evaporation to lose 90% of the water. As the rock loses water, the equilibrium relative humidity remains at 99% until an appreciable amount (80–90%) of the pore water is lost, after which the equilibrium relative humidity starts to decrease. The relative humidity remains at > 80% (68 h) long after the water content falls to < 98% (19 h) - the point at which liquid water is estimated no longer to be present. Lichens can remain active in air with high relative humidity (> 80%). Thus, the pore size distribution of the sandstone may play a role in explaining why lichens dominate these sandstones.

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.

Here, we report the first discovery of Antarctic fossil resin (commonly referred to as amber) within a ~5 cm-thick lignite layer, which constitutes the top part of a ~3 m-long palynomorph-rich and root-bearing carbonaceous mudstone of mid-Cretaceous age (Klages et al. 2020). The sedimentary sequence (Fig. 1) was recovered by the MARUM-MeBo70 seafloor drill rig at Site PS104_20 (73.57° S, 107.09° W; 946 m water depth) from the mid-shelf section of Pine Island trough in the Amundsen Sea Embayment, West Antarctica, during RV Polarstern Expedition PS104 in early 2017 (Gohl 2017; Fig. 1a). So far, amber deposits have been described from every continent except Antarctica (Langenheim 2003, Quinney et al. 2015; Fig. 1a).

Ireland has a rich Antarctic history, with Bransfield, Crozier, Shackleton, Crean and others acting as key Irish individuals in Antarctic exploration. Recognized as a source of Irish national pride, memorials, stamps, coins and a government research vessel all commemorate their polar feats. Today, a large proportion of Ireland's citizens visit the Antarctic region and Irish researchers produce high levels of academic outputs on Antarctic topics relative to many other nations. However, Ireland has not acceded to any Antarctic Treaty System instruments, despite a 20 year campaign to do so by cross-party Irish politicians. Ireland has the largest population of any nation in the European Union (EU) yet to accede to the Treaty and is much larger than some existing Treaty signatory states. However, Treaty accession provides no entitlement to participate in Antarctic governance, which is reserved for Consultative Parties, and therefore undertaking the associated legal and administrative work may be considered a poor use of available resources. Ireland's attainment of consultative status would be an even more complex and resource-intensive goal, but collaboration with the EU and other global partners could be a cost-effective solution that may also indirectly support Ireland's ambitions for Observer status at the Arctic Council.

Most of the Ross Sea has been designated a marine protected area (MPA), proposed ‘to protect ecosystem structure and function’. To assess effectiveness, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) selected Adélie (Pygoscelis adeliae) and emperor (Aptenodytes forsteri) penguins, Weddell seals (Leptonychotes weddellii) and Antarctic toothfish (Dissostichus mawsoni) as ecosystem change ‘indicator species’. Stable for decades, penguin and seal populations increased during 1998–2018 to surpass historical levels, indicating that change in ecosystem structure and function is underway. We review historical impacts to population trends, decadal datasets of ocean climate and fishing pressure on toothfish. Statistical modelling for Adélie penguins and Weddell seals indicates that variability in climate factors and cumulative extraction of adult toothfish may explain these trends. These mesopredators, and adult toothfish, all prey heavily on Antarctic silverfish (Pleuragramma antarcticum). Toothfish removal may be altering intraguild predation dynamics, leading to competitive release of silverfish and contributing to penguin and seal population changes. Despite decades of ocean/weather change, increases in indicator species numbers around Ross Island only began once the toothfish fishery commenced. The rational-use, ecosystem-based viewpoint promoted by CCAMLR regarding toothfish management needs re-evaluation, including in the context of the Ross Sea Region MPA.