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: 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: 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: 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.

Description: Arctic sea ice is rapidly declining in presence, thickness and extent. The consequences that this has for the overall biodiversity in Arctic marine ecosystems are poorly addressed. Especially the so-called sympagic meiofauna, the many tiny organisms living in sea ice, is rarely identified to species level. Here we present the first record of the hydrozoan Sympagohydra tuuli living in sea ice in the Svalbard fjords (European Arctic). Previously, this tiny ice-cnidarian has only been reported from sea ice of Barrow (Alaska), the Canadian Arctic and the central Arctic Ocean. In April 2015, two small hydrozoans were recorded in the landfast sea ice in Van Mijenfjorden (West Spitsbergen). Both of them were preserved in ethanol and one specimen was successfully identified with Sanger sequencing. DNA barcoding confirmed it to be the Protohydridae S. tuuli. Little is known about S. tuuli lifecycle, but its occurrence within the sea ice of seasonal ice-covered fjords in Western Svalbard with no sea-ice connection to the Arctic Ocean strengthens the theory about a sympago-benthic life strategy. We propose that S. tuuli has a pan-Arctic distribution and only spends parts of its life cycle in sea ice.

Description: The present work represents a contribution to the ecology of a little known host parasite association, i.e. sucking lice and Antarctic seals. The information available regarding the health status of Antarctic seals is limited and little is known about the ecology and effect of parasites on these hosts. Particularly, data regarding Antarctic louse infestation are scarce. Therefore, the main goal of this study is to report the results of a survey of the louse infestation of Lepidophthirus macrorhini (Anoplura, Echinophthiriidae) on 26 elephant seals ( Mirounga leonina ) and on a Weddell seal ( Leptonychotes weddelli ) from eastern Antarctic Peninsula.

Description: Deschampsia antactica E. Desv. is one of the only two native vascular plants of Antarctica, having a disjunct distribution with South America. Its presence in different environmental conditions turns it into an interesting evolution model, particularly for genomic evolutionary studies. The repetitive DNA is a genome component that cause important changes in genome size and chromosome organization, and therefore, its variation is very important in group’s delimitation. Some tandem repetitive DNA sequences, known as satellite DNA (satDNAs) are shared between many groups of Poaceae (e.g., of these are the CON1, CON2, COM1, and COM2 sequences) highlighting its evolutionary component. This study aims to identify, classify, and characterize repetitive elements in the D. antarctica genome by clustering analysis of genome sequences, focusing on the CON1, CON2, COM1, and COM2. Repetitive DNA represented about 73.3% of the D. antarctica genome. All studied populations presented loci for the studied satDNAs but the distribution pattern showed differences that seem to be related to the geographic distribution. The analysis of CON/COM sequences in D. antarctica contributes to the understanding of these elements in Poaceae genomes and highlights the importance of changes in chromosome organization of repetitive DNA in populations with fragmented geographical distribution. The distribution of such chromosome changes may both reflect the process of colonization of D. antarctica in Antarctica and explain some evolutionary processes of differentiation in Deschampsia species complex in the Patagonia, which is still unresolved with other DNA sequences.

Description: Polar bears ( Ursus maritimus ) are apex predators of the Arctic, which exposes them to an array of natural and anthropogenic stress factors. Metabolomics analysis profiles endogenous metabolites that reflect the response of biological systems to stimuli, and the effects of multiple stressors can be assessed from an integrated perspective. A targeted, quantitative, liquid chromatography–mass spectrometry-based metabolomics platform [219 metabolites including amino acids, biogenic amines, acylcarnitines, phosphatidylcholines (PCs), sphingomyelins, hexoses (Hex), and fatty acids (FAs)] was applied to the muscle and liver of polar bears from the Southern and Western Hudson Bay (Canada) subpopulations (SHB and WHB, respectively). Multivariate statistics were then applied to establish whether bears were discriminated by sex and/or subpopulation. Five metabolites identified by variable importance projection (VIP) discriminated the hepatic profiles of SHB males and females (Hex, arginine, glutamine, one PC, one sphingomyelin), while fifteen metabolites (primarily PCs along with leucine) contrasted the livers of males from SHB and WHB. Metabolite profiles in the muscle of male and female bears could not be differentiated; however, the muscles of SHB and WHB males were discriminated primarily by PCs and FAs. Stable isotope ratios (δ 13 C and δ 15 N) were variably related to metabolites; δ 13 C was correlated with some VIP metabolite concentrations, particularly in comparisons of male bears from SHB and WHB, suggesting an influence of dietary differences. However, δ 15 N and age exhibited few, relatively weak correlations with metabolites. The metabolite profiles discriminating the sexes and subpopulations may have utility for future assessments regarding the effects of specific stressors on the physiology of Hudson Bay polar bears.