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The feeding behaviour of adult Eusirus perdentatus was observed in aquaria. These observations and the analysis of gut contents of preserved specimens demonstrate that this species is a carnivorous predator feeding on polychaetes, amphipods and other small crustaceans. Apparently the localization and capture of prey in aquaria follows a fixed pattern.

Arctic ecosystems are under pressure from climate change and atmospheric nitrogen (N) deposition. However, knowledge of the ecology of microbial communities and their responses to such challenges in Arctic tundra soil remain limited, despite the central role these organisms play for ecosystem functioning. We utilised a plot-scale experiment in High Arctic tundra on Svalbard to investigate short-term variation (9 days), following simulation of a N deposition event (4 kg N ha−1 yr−1), in the structure and abundance of bacterial, archaeal and fungal communities between organic and mineral soil horizons. T-RFLP analysis showed significant differences between horizons in bacterial and archaeal community structure. Q-PCR analysis showed that fungal abundance did not differ significantly between soil horizons, whilst bacterial and archaeal abundance was significantly higher in mineral than in organic horizons, despite soil water and total C and N contents being significantly greater in the organic horizon. In the organic horizon, bacterial community structure and fungal abundance varied significantly over time. In the mineral horizon, there was significant variation over time in bacterial abundance, in archaeal community structure and in both fungal community structure and abundance. In contrast, N deposition did not lead to significant variation in either the structure or the abundance of microbial communities. This research demonstrates that microbial community structure and abundance can change rapidly (over only a few days) in Arctic tundra soils and also differently between soil horizons in response to different environmental drivers. Moreover, this variability in microbial community structure and abundance is soil horizon- and taxonomic domain-specific, highlighting the importance of investigating microbial communities across all soil horizons and over short periods of time.

Spectacled eiders (Somateria fischeri) winter among leads in the Bering Sea pack ice, where they dive 40–70 m for benthic prey. During the first icebreaker cruises into that area, esophagi of collected eiders contained only clams, mostly Nuculana radiata, with no trace of the once-dominant Macoma calcarea. Alternative prey used elsewhere (snails, amphipods, other bivalves) were available but not eaten. Eiders ate mainly N. radiata 18–24 mm long, although M. calcarea of this length contained 62% more energy. Percent body lipid of eiders averaged 12±3% (SD) for 26 adult males and 14±3% for 12 adult females. Mean body mass (±SE) of these males in late March (1,688±21 g) was higher than reported for 53 males after arriving at breeding areas in late May (1,494±14 g). Body mass of these females (1,550±35 g) was lower (but not significantly) than reported for 11 females upon arrival at breeding sites (1,623±46 g). In 1999, the last spectacled eiders left the wintering area on 21 April, 4–8 weeks before their typical arrival at breeding sites. Their location is unknown in the interim, when habitats used appear critical to acquiring reserves for reproduction.

Antarctic fish, such as the Trematomus bernacchii, living at −1.9°C maintain a serum osmolality of around 600 mOsm kg−1, nearly twice that of temperate fish. Upon warm acclimation, Antarctic fish significantly lower their serum osmolality. It has been suggested that this response to warm acclimation is due to stress. The purpose of this study was to determine, whether upon warm acclimation there was a change in the levels of the stress hormone cortisol and hematocrit associated with the decrease in serum osmolality. T. bernacchii were warm acclimated up to 4 weeks and serum osmolality, cortisol and hematocrit were measured. Upon warm acclimation to +1.6 and +3.8°C over the course of 4 weeks, T. bernacchii significantly lowered their serum osmolality (from 547 ± 4 mOsm kg−1 to 494 ± 6 and 489 ± 4 mOsm kg−1, respectively), yet did not alter their serum cortisol (29 ± 6 nl ml−1) or hematocrit (22 ± 1%) levels. These results suggest that warm acclimation does not induce a stress response in T. bernacchii.

Studies of annual successions and inter-annual variations in sub-Arctic and Arctic microplankton assemblages are required in order to understand the structure and function of marine ecosystems. This study depicts the microplankton (>20 μm) structure in a sub-Arctic tidewater glacial fjord system, SW Greenland. The descriptions are based on monthly net hauls collected between January 2006 and December 2010. Two blooms, with distinctive species compositions, were identified across all years: a spring bloom and a summer/autumn bloom. In addition, the winter season—with weak stratification, deep tidal mixing, and dense coastal inflows—was characterised by a separate species composition at much lower abundance. Here, the highest variety of microplankton groups was recorded and represented by diatoms (Chaetoceros spp. and Thalassiosira spp.), silicoflagellates, dinoflagellates, and ciliates. During the spring bloom, species correlated with higher light intensities, i.e. haptophytes and diatoms (Thalassiosira spp. and Fragilariopsis spp.), dominated the microplankton assemblage. Among these, diatoms were also correlated with cooler and fresher waters influenced by springtime melt. During the summer/autumn bloom, the microplankton assemblage was mainly represented by diatoms, such as Chaetoceros spp. ‘Low-saline’ chrysophytes were also present. The latter bloom coincides with elevated temperatures in the fjord and renewal of nutrients due to the onset of glacial meltwater run-off from the Greenland Ice Sheet. Our study shows a yearly recurrent succession of microplankton assemblages and that the annual succession is controlled primarily by ocean–fjord–glacier interactions.

Southern giant petrels (Macronectes giganteus) are opportunistic generalists whose feeding strategies include hunting, scavenging and fishing. While seals are important for southern giant petrels as a source of carrion, we documented that live seals also provide feeding opportunities for southern giant petrels. We tracked breeding southern giant petrels from Harmony Point, Antarctica, during incubation and chick rearing with solar-powered GPS-UHF devices. Tracking results showed that animals often visited confirmed haul-out sites of seals, mainly Weddell seals (Leptonychotes weddellii). Feeding on seal faeces was confirmed by direct observation. Southern giant petrels were more likely to visit haul-out sites during incubation than during chick-rearing. This behaviour suggests that the birds fed on seal faeces mainly when fasting, which could last as long as 15 days. Seal faeces could be a resource consumed to quickly recover from the fast before leaving for a longer trip.

The importance of snowmelt as a source of moisture for the crustose lichen Buellia frigida in the early austral summer was investigated at Cape Geology, Granite Harbour, southern Victoria Land (77°01′S, 162°32′E). Surface and air temperatures and irradiance were recorded on the surface of a slightly inclined granite boulder for 5 weeks. Observations were made of lichen thallus hydration during a 5-day period. The results confirmed the strong warming effect of high irradiance; the rock surface and hydrated lichen were up to 19K above air temperature and, overall, the rock surface averaged 5.5K warmer. Therefore water condensation on the rock surface (dew or hoarfrost) was not possible during that period. Thalli were moistened by meltwater from both a small area of snow pack and from occasional snowfalls. The distribution of lichen thalli on the rock surface can be explained by the frequency and duration of meltwater moistening. Despite the very high irradiance whilst moist, the lichens seem well adapted to the combination of hydration, low temperatures and strong light.