Description: Competition between individuals of the same or different species affects spatial distribution of organisms at any given time. Consequently, a species geographical distribution is related to population dynamics through density-dependent processes. Small Arctic rodents are important prey species in many Arctic ecosystems. They commonly show large cyclic fluctuations in abundance offering a potential to investigate how landscape characteristics relates to density-dependent habitat selection. Based on long-term summer trapping data of the Norwegian lemming ( Lemmus lemmus ) in the Scandinavian Mountain tundra, we applied species distribution modeling to test if the effect of environmental variables on lemming distribution changed in relation to the lemming cycle. Lemmings were less habitat specific during the peak phase, as their distribution was only related to primary productivity. During the increase phase, however, lemming distribution was, in addition, associated with landscape characteristics such as hilly terrain and slopes that are less likely to get flooded. Lemming habitat use varied during the cycle, suggesting density-dependent changes in habitat selection that could be explained by intraspecific competition. We believe that the distribution patterns observed during the increase phase show a stronger ecological signal for habitat preference and that the less specific habitat use during the peak phase is a result of lemmings grazing themselves out of the best habitat as the population grows. Future research on lemming winter distribution would make it possible to investigate the year around strategies of habitat selection in lemmings and a better understanding of a fundamental actor in many Arctic ecosystems.

Description: Studies investigating viral ecology have mainly been conducted in temperate marine and freshwater habitats. Fewer reports are available on the often less accessible “extreme environments” such as hot springs. This study investigated prokaryotic- and virus-like particles (VLP) associated to hot springs, themselves situated in cold environments of the Southern Hemisphere (i.e. in the French Southern and Antarctic Lands). This was performed by examining their abundance in hot springs and surrounding temperate seawater using both epifluorescence microscopy (EFM) and flow cytometry (FCM), which was applied for the first time to such ecosystems. On one hand, prokaryotic abundances of 4.0 × 10 5 –2.2 × 10 6  cell mL −1 and 7.0 × 10 4 –2.8 × 10 6  cell mL −1 were measured using EFM and FCM, respectively. The abundances of virus-like particles (VLP), on the other hand, ranged between 9.8 × 10 5 and 7.5 × 10 6 particles mL −1 when using EFM, and between 1.3 × 10 5 and 6.2 × 10 6 particles mL −1 when FCM was applied. A positive correlation was found between VLP and prokaryotic abundances, while the virus-to-prokaryote ratio was generally low and ranged between 0.1 and 6. In parallel, samples and culture supernatants were also visualised using transmission electron microscopy. For this, enrichment cultures were prepared using environmental samples. Both raw sample and enrichment culture—supernatants were analysed for the presence of VLPs. Observations revealed the presence of Caudovirales, membrane vesicles and possibly a new type of virion morphology, associated to members of the order Thermotogales, a thermophilic and anaerobic bacterium.

Description: Although research on parasitic diseases in Antarctic birds is scarce and the information largely fragmented, an increasing number of studies are currently in progress in this area. The host/parasite relationship is very important for understanding the impact of parasitism on the seabirds’ feeding ecology, especially in those isolated regions where the host is extremely sensitive to new diseases. Penguins are a big favorite for these studies because of their importance as indicators of change in the Antarctic ecosystem. This study aims at adding information on gastrointestinal parasites of the Emperor Penguin Aptenodytes forsteri from Snow Hill colony. Based on a sample of 43 individuals found freshly dead (3 adults and 40 chicks) from predation or starvation, the gastrointestinal helminth community in Emperor penguins was composed of two species of cestodes ( Parorchites zederi and Tetrabothrius sp.) and three species of nematodes ( Stegophorus macronectes, Tetrameres sp. and Contracaecum osculatum ). This is the first record of S. macronectes in the Emperor Penguin. The low parasite richness observed might be related to the stenophagic and pelagic diet of this host.

Description: The authors regret an error in the published article, where incorrect data was used to produce Figure 2, showing the temporal development of pH over the duration of the experiment. The corrected Fig. 2 shows that the error did not affect the interpretation of nor the conclusions drawn from the present dataset. The original article has been corrected.

Description: An integrative inventory of the amphipod scavenging fauna (Lysianassoidea), combining morphological identifications with DNA barcoding, is provided here for the Filchner area situated in the south-eastern Weddell Sea. Over 4400 lysianassoids were investigated for species richness and relative abundances, covering 20 different stations and using different sampling devices, including the southernmost baited traps deployed so far (76°S). High species richness was observed: 29 morphospecies of which 5 were new to science. Molecular species delimitation methods were carried out with 109 cytochrome c oxidase I gene (COI) sequences obtained during this study as well as sequences from specimens sampled in other Antarctic regions. These distance-based analyses (trees and the Automatic Barcode Gap Discovery method) indicated the presence of 42 lineages; for 4 species, several (cryptic) lineages were found. More than 96% of the lysianassoids collected with baited traps belonged to the species Orchomenella pinguides s. l. The diversity of the amphipod scavenger guild in this ice-bound ecosystem of the Weddell Sea is discussed in the light of bottom–up selective forces. In this southernmost part of the Weddell Sea, harbouring spawning and nursery grounds for silverfish and icefishes, abundant fish and mammalian food falls are likely to represent the major food for scavengers. Finally, the importance of biodiversity surveys in the context of the establishment of a marine protected area in this region (Weddell Sea MPA) is highlighted and how future studies can contribute to a better understanding the ecological role of scavengers in this system is discussed.

Description: The original article shows TDFe in Table 1 as µmol L −1 . The correct TDFe in Table 1 should be nmol L −1 .

Description: Records of vagrant marine organisms provide important information on oceanographic anomalies and the changing environment. We report on an immature Weddell seal, Leptonychotes weddellii , sighted at Calheta Beach in Trindade Island (20°31′S 29°19′W), Brazil, on July 9, 2015. A number of injuries were noted, including blisters on the dorsal surface of the body and a small cut at the right-hand side distal portion of the mandible. Based on its size and the state of fusion of cranial sutures, we suggest that it was born in the 2014 austral spring and was possibly 8–10 months old. We suggest that it comes from the South Shetland Islands, Antarctic Peninsula. This is the closest breeding location of this species. This sighting is the northernmost of L. weddellii , being at least ~ 5140 km from the Antarctic Peninsula (63°12′S 55°04′W) and ~ 2840 km north from the second northernmost sighting of this species in Uruguay.

Description: Nasal mites occur in different groups of birds, but little is known about their diversity associated with seabirds. The aim of this study was to verify the presence of nasal mites in the Magellanic Penguin ( Spheniscus magellanicus ), and to study their parasitological indices. For that purpose, the nasal cavity of 99 Magellanic Penguin found in the southern coast of Rio Grande do Sul, Brazil, was dissected and examined. Rhinonyssus sphenisci (Rhinonyssidae) occurred in 17 hosts (17.2%) with mean intensity of 11.52 mites/host. There were no significant differences in prevalence and mean intensity of infection between male and female hosts. Rhinonyssus sphenisci had already been reported in S. magellanicus ; however, there had been no information on parasitological indices. Therefore, this study reported infection levels of R. sphenisci in S. magellanicus.

Description: Geothermal areas, such as volcanoes, might have acted as glacial microrefugia for a wide range of species. The heavily glaciated but volcanically active Antarctic continent presents an ideal system for assessing this hypothesis. Ice-free terrain around volcanoes in Antarctica is, however, often restricted to small patches, whereas subglacial cave systems, formed by vented volcanic steam, can be extensive and interconnected. No observations of macrobiota have yet been made for subglacial geothermal environments in Antarctica, but these organisms are often patchily distributed and can be difficult to find. We carried out metabarcoding (eDNA) analyses of soil samples taken from exposed areas on three volcanoes in Victoria Land, and subglacial caves on Mount Erebus. We found evidence of numerous eukaryotic groups, including mosses, algae, arthropods, oligochaetes and nematodes, at both exposed and subglacial sites. Our findings support the notion that geothermal areas—including subglacial environments—can nurture biodiversity in glaciated regions.

Description: Ice-breeding seals use vocal communication mainly during breeding season. The vocal function of aquatic mating, ice-associated ribbon seals ( Histriophoca fasciata ) has been unknown since they produce sounds in both breeding and non-breeding seasons. We examined the timing of their vocal presence in relation to environmental factors to infer the function of their calls in the Nemuro Strait, northern Japan, since this area is the possible southern limit of their breeding range. Vocalizations of ribbon seals were irregularly sampled from November 2012 to March 2014 in the Nemuro Strait and were compared with sea ice presence, time of day, and tidal currents. Ribbon seal downsweeps were detected in February 2013 and March 2014 only when sea ice was present along the Shiretoko Peninsula in the strait, with more detections in March leading up to the spring breeding season. Downsweep detections decreased in the middle of the day, indicating that ribbon seals were likely to be hauled out during this time. Vocalizing at night and early morning would probably reflect the increased opportunity for attracting females underwater. Our study suggests that the seal vocalizations in concurrence with sea ice presence in the Nemuro Strait could function as underwater communication for breeding.