The flightless midge Eretmoptera murphyi is thought to be continuing its invasion of Signy Island via the treads of personnel boots. Current boot-wash biosecurity protocols in the Antarctic region rely on microbial biocides, primarily Virkon® S. As pesticides have limited approval for use in the Antarctic Treaty area, we investigated the efficacy of Virkon® S in controlling the spread of E. murphyi using boot-wash simulations and maximum threshold exposures. We found that E. murphyi tolerates over 8 h of submergence in 1% Virkon® S. Higher concentrations increased effectiveness, but larvae still exhibited > 50% survival after 5 h in 10% Virkon® S. Salt and hot water treatments (without Virkon® S) were explored as possible alternatives. Salt water proved ineffective, with mortality only in first-instar larvae across multi-day exposures. Larvae experienced 100% mortality when exposed for 10 s to 50°C water, but they showed complete survival at 45°C. Given that current boot-wash protocols alone are an ineffective control of this invasive insect, we advocate hot water (> 50°C) to remove soil, followed by Virkon® S as a microbial biocide on ‘clean’ boots. Implications for the spread of invasive invertebrates as a result of increased human activity in the Antarctic region are discussed.

The shape (derived from landmark-based geometric morphometrics), condition (Fulton index) and diet (determined through gut content analysis) were described for the pike icefish Champsocephalus esox (Channichthyidae) from Última Esperanza sound, south-west Patagonia, Chile. Based on the length-weight relationship, females were heavier at length than males. Nevertheless, the Fulton index was similar between males and females. The morphospace of C. esox showed high intraspecific variability in the dorsoventral position of the tip of the snout, anus and the ventral insertion of the pectoral fin, as well as the anteroposterior position of the premaxilla, opercle and anus. This indicates the existence of phenotypic plasticity, leading to specimens with larger jaws and heads but shorter trunks, or specimens with shorter jaws and heads but larger trunks. This phenotypic plasticity was independent of size and sex. The feeding incidence was similar between sexes (34.1% and 47.2% for males and females, respectively). Diets consisted of only fish, small notothenioids of the genus Patagonotothen (P. tessellata, P. cornucola and P. sima), showing similarities between males and females. Finally, C. esox is the second notothenioid species, and the first outside of Antarctica, to display phenotypic plasticity in its body shape.

Antarctic toothfish Dissostichus mawsoni and Weddell seals Leptonychotes weddellii are important mesopredators in the waters of the Antarctic continental shelf. They compete with each other for prey, yet the seals also prey upon toothfish. Such intraguild predation means that prevalence and respective demographic rates may be negatively correlated, but quantification is lacking. Following a review of their natural histories, we initiate an approach to address this deficiency by analysing scientific fishing catch per unit effort (CPUE; 1975–2011 plus sporadic effort to 2018) in conjunction with an annual index of seal abundance in McMurdo Sound, Ross Sea. We correlated annual variation in scientific CPUE to seal numbers over a 43 year period (1975–2018), complementing an earlier study in the same locality showing CPUE to be negatively correlated with spatial proximity to abundant seals. The observed relationship (more seals with lower CPUE, while controlling for annual trends in each) indicates the importance of toothfish as a dietary item to Weddell seals and highlights the probable importance of intra- and inter-specific competition as well as intraguild predation in seal-toothfish dynamics. Ultimately, it may be necessary to supplement fishery management with targeted ecosystem monitoring to prevent the fishery from having adverse effects on dependent species.

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.

Species inventories are essential to the implementation of conservation policies to mitigate biodiversity loss and maintain ecosystem services and their value to the society. This is particularly topical with respect to climate change and direct anthropogenic effects on Antarctic biodiversity, with the identification of the most at-risk taxa and geographical areas becoming a priority. Identification tools are often neglected and considered helpful only for taxonomists. However, the development of new online information technologies and computer-aided identification tools provides an opportunity to promote them to a wider audience, especially considering the emerging generation of scientists who apply an integrative approach to taxonomy. This paper aims to clarify essential concepts and provide convenient and accessible tools, tips and suggested systems to use and develop knowledge bases (KBs). The software Xper3 was selected as an example of a user-friendly KB management system to give a general overview of existing tools and functionalities through two applications: the ‘Antarctic Echinoids’ and ‘Odontasteridae Southern Ocean (Asteroids)’ KBs. We highlight the advantages provided by KBs over more classical tools, and future potential uses are highlighted, including the production of field guides to aid in the compilation of species inventories for biodiversity conservation purposes.

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.

Year-round monitoring of Erebus volcano (Ross Island) has proved challenging due to the difficulties of maintaining continuous power for scientific instruments, especially through the Antarctic winter. We sought a potential solution involving the harvesting of thermal energy dissipated close to the summit crater of the volcano in a zone of diffuse hot gas emissions. We designed, constructed and tested a power generator based on the Seebeck effect, converting thermal energy to electrical power, which could, in principle, be used to run monitoring devices year round. We report here on the design of the generator and the results of an 11 day trial deployment on Erebus volcano in December 2014. The generator produced a mean output power of 270 mW, although we identified some technical issues that had impaired its efficiency. Nevertheless, this is already sufficient power for some monitoring equipment and, with design improvements, such a generator could provide a viable solution to powering a larger suite of instrumentation.

Cetacean fossils have been recorded from middle and late Eocene deposits on Seymour Island since the beginning of the twentieth century and include fully aquatic Basilosauridae and stem Neoceti. Here, we report a small cetacean vertebra tentatively referred to as Neoceti from the late Eocene of Seymour Island. It shows a mosaic of traits, some of which are characteristic of early Neoceti (anteroposteriorly long transverse processes; a ventral keel on the ventral side of the centrum; thin pedicles of the neural arch), whereas others are shared with Basilosauridae (low-placed bases of the transverse processes). However, some traits are unique and may be autapomorphic: presence of separate prezygapophyses on the vertebra at the thoracic/lumbar boundary and a proportionally short centrum. Both traits imply a fast swimming style, which is characteristic of modern dolphins rather than Eocene cetaceans. Thus, this specimen can be identified as Neoceti indet., with some hypothetical odontocete affinities. Along with a few other Eocene whale taxa, it seems to be among the earliest known members of Neoceti on Earth. The finding of small and fast-swimming Neoceti in Antarctica also demonstrates early diversification of cetaceans and ecological niche partitioning by them dating back as early as the late Eocene.

New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

Debris-covered glaciers constitute a large part of the world's cryosphere. However, little is known about their long-term response to multi-millennial climate variability, in particular in the Southern Hemisphere. Here, we provide first insights into the response of a debris-covered glacier to multi-millennial climate variability in the sub-Antarctic Kerguelen Archipelago, which can be compared to that of recently investigated debris-free glaciers. We focus on the Gentil Glacier and present 13 new 36Cl cosmic-ray exposure ages from moraine boulders. The Gentil Glacier experienced at least two glacial advances: the first one during the Late Glacial (19.0–11.6 ka) at ~14.3 ka and the second one during the Late Holocene at ~2.6 ka. Both debris-covered and debris-free glaciers advanced broadly synchronously during the Late Glacial, most probably during the Antarctic Cold Reversal event (14.5–12.9 ka). This suggests that both glacier types at Kerguelen were sensitive to abrupt temperature changes recorded in Antarctic ice cores, associated with increased moisture. However, during the Late Holocene, the advance at ~2.6 ka was not observed in other glaciers and seems to be an original feature of the debris-covered Gentil Glacier, related to either distinct dynamics or to distinct sensitivity to precipitation changes.