Lentic freshwater habitats are important centres of biodiversity within the infrequent ice-free oases across Antarctica. Given imminent climate changes, it is crucial to catalogue these habitats in order to provide baseline data for future monitoring and biological surveys. The lacustrine systems of Clearwater Mesa, a previously unexplored part of James Ross Island, north-eastern Antarctic Peninsula, are described here. We conducted basic geomorphological and limnological surveys over three Antarctic summers (2009–16) to characterize landscape evolution, infer the origin of lake basins and assess the variability in their water chemistry. Stable shallow lakes, formed in depressions between lava tumuli following the last deglaciation, were found to dominate the volcanic mesa, although several peripheral lakes in ice-proximal settings appear to have formed recently as a result of post-Neoglacial ice recession. We found large heterogeneity in conductivity (~10–7000 μS cm−1), despite the lithologically uniform substrate. This variability was shown to be related to lake type, basin type (open vs closed), meltwater source and proximity to the coast. Inter-annual differences were attributed to changes in sea spray influx and snow accumulation driven by variable weather conditions. Overall, the ion composition of lakes suggested that sea spray was the dominant source of ions, followed by the weathering of bedrock.

Adélie penguins are renowned for their natal philopatry on land-based colonies, requiring small pebbles to be used for nests. We report on an opportunistic observation via aerial survey, where hundreds of Adélie penguins were documented displaying nesting behaviours on fast ice ~3 km off the coast of Cape Crozier, which is one of the largest colonies in the world. We counted 426 Adélie penguins engaging in behaviours of pair formation, spacing similarly to normal nest distributions and lying in divots in the ice that looked like nests. On our first visit, it was noticed that the guano stain was bright pink, consistent with krill consumption, but had shifted to green over the course of ~2 weeks, indicating that the birds were fasting (a behaviour consistent with egg incubation). However, eggs were not observed. We posit four hypotheses that may explain the proximate causes of this behaviour and caution against future high-resolution satellite imagery interpretation due to the potential for confusing ice-nesting Adélie penguins with the presence of emperor penguin colonies.

We developed a random, stratified, vertical longline survey in McMurdo Sound, Antarctica, to compare the local age and size composition, diet and reproductive status of Antarctic toothfish (Dissostichus mawsoni) with those observed from a vessel-based survey of the southern Ross Sea shelf that includes a McMurdo Sound stratum. Results indicated that southern McMurdo Sound toothfish were larger and older than those a short distance away in northern McMurdo Sound. These data, in addition to recoveries of tagged fish, suggest that the large toothfish in McMurdo Sound may have limited mixing with the rest of the population. The potential effects of climate change and fishing in northern areas on toothfish abundance in McMurdo Sound will depend on the mechanism of toothfish recruitment to McMurdo Sound. Understanding the ecological relationships between McMurdo Sound toothfish and the larger population is required to predict these impacts. Furthermore, because toothfish predators (type C killer whales Orcinus orca, Weddell seals Leptonychotes weddellii) are abundant in the south-west margins of the Ross Sea, it is important to monitor toothfish in McMurdo Sound as part of the monitoring programme for the Ross Sea region Marine Protected Area.

In Antarctica, the genus Bartramia has been restricted to a single polymorphic species, B. patens. Its status as a separate species or a subspecies of the Northern Hemisphere B. ithyphylla was debated. In the present paper, we combine analyses of chloroplast (trnS–rps4–trnT–trnL–trnF region) and nuclear ITS sequences with a reinvestigation of morphological characteristics to infer the identity of Antarctic Bartramia. Phylogenetic and Automatic Barcode Gap Discovery (ABGD) species delimitation analyses indicate that the species diversity of Bartramia in Antarctica has been underestimated, since two species were identified, both belonging to Bartramia sect. Pyridium. Of these, B. subsymmetrica is a new record of the species for Antarctica, as it has previously only been recorded from Livingston Island, South Shetlands. The other species is B. patens, which is separated from B. ithyphylla by newly inferred morphological characteristics and is a sister species to the latter in the molecular phylogenetic analyses. Consequently, we consider B. ithyphylla to be a Northern Hemisphere instead of a bipolar species. The suggested conspecificity of both taxa into one species in the ABGD analysis is considered to result from overlumping by this species delimitation method. The delimitation of the three species of section Bartramia (B. halleriana, B. mossmaniana and B. pomiformis) and the circumscription of the genus Bartramia are discussed.

Antarctica is no longer a pristine environment due to atmospheric pollution, fuel spills, inadequate waste management and wastewater discharges from anthropogenic activities (Harris 1998, Stark et al. 2015). Approximately 37% of the permanent stations and 69% of the summer stations lack any form of sewage treatment (Gröndahl et al. 2009). The characteristics of wastewater from stations are also of concern because they are a complex mix of contaminants containing human waste, cosmetics, viruses, dyes, detergents, medications, chemicals from laboratories and even microplastics (Bhardwaj et al. 2018). In Antarctica, treatment plants discharge treated water into the sea and then sludge is packed and sealed into drums for later shipment to Chile. Nevertheless, sewage sludge (c. 59–88% organic matter) could become a biosolid instead of being a waste if correctly stabilized. The Ecuadorian Antarctic station ‘Pedro Vicente Maldonado’ produced c. 200 kg of sewage sludge during expeditions in 2017 and 2018. Thus, the aim of the present study was to biostabilize sewage sludge using two methods (one thermal and one biological) at the Ecuadorian Antarctic station. As a result, the stabilization of sewage sludge produced a biosolid that was easier and more cost effective to transport, avoiding odour problems.

Bathymetric data of unprecedented resolution are used to provide insights into former ice dynamics and glacial processes in a western Antarctic Peninsula embayment. An assemblage of submarine glacial landforms, which includes subglacially produced streamlined features and ice-marginal ridges, reveals the former pattern of ice flow and retreat. A group of more than 250 small (< 1–3 m high, 10–20 m wide) and relatively evenly spaced recessional moraines was identified beyond the margin of Philippa Glacier. The small recessional moraines are interpreted to have been produced during short-lived, possibly annual re-advances of a grounded ice margin during overall retreat. This is the first time that these features have been shown to be part of the assemblage of landforms produced by tidewater glaciers on the Antarctic Peninsula. Glacier-terminus changes during the last four decades, mapped from LANDSAT satellite images, were analysed to determine whether the moraines were produced during recent still-stands or re-advances of Philippa Glacier and to further investigate the short-term (annual to decadal) variability in ice-marginal position in tidewater glacier systems. The asynchronous response of individual tidewater glaciers in Darbel Bay is interpreted to be controlled mainly by local topography rather than by glacier catchment-area size.