Description: Zooplankton are the link connecting primary producers to higher trophic levels, and knowing their distribution and community is important for predicting the distribution of predator species, like fish, seabirds, and marine mammals. However, data from open Arctic oceans are still scarce. In autumn, tens of millions of the planktivorous little auks ( Alle alle ) (about 75 % of the world’s population) and millions of thick-billed murres ( Uria lomvia ) pass through the Baffin Bay. To investigate their potential food sources, we investigated the spatial and vertical distribution of zooplankton and small fishes in the upper 500 m of southern Baffin Bay in September 2009. The zooplankton community was dominated by copepods (55 % of abundance in the upper 500 m), primarily of the genus Calanus . Other important zooplankton taxa included Limacina helicina , Chaetognatha, and Cirripedia nauplii. On the Greenland Shelf, most Calanus were late copepodite stages and most were found at the depths of 〉200 m, suggesting they were in diapause. On the Canadian Shelf, there were relatively more Calanus in the near-surface layers, which were probably still actively feeding and which were available to visual predators such as seabirds and fish. The acoustic survey showed the highest density of polar cod Boreogadus saida in the upper 50 m on the western part of the Greenland Shelf. A particularly high biomass of both zooplankton and polar cod was found in the central part of the basin in association with a local relatively shallow area.

Description: The Southern elephant seal ( Mirounga leonina) is a major consumer from the Southern Ocean. This species is highly sexually dimorphic and frequently exhibits resource partitioning according to sex and/or age classes. This study analysed the feeding habits of the M. leonina population from Isla 25 de mayo (King George Island) in the spring/summer seasons of 1995/1996–2002/2003. A total of 232 individuals from different sex-age groups were stomach lavaged. The analysis of stomach samples showed that cephalopods were the main prey followed by fish, their frequency of occurrence being 98.1 and 17.9 % respectively. Cephalopods were dominated by the Antarctic glacial squid, Psychroteuthis glacialis , which occurred in 83 % of samples, constituting 57.2 % in numbers and 61.3 % in mass. Octopods were of lesser relevance, occurring in 18 % of samples, but became more important in the diet of male individuals. Juvenile seals fed on a lower variety of cephalopod prey than older ones. This would coincide with the diving pattern characteristic of the different sex-age categories of seals. The predominance of P. glacialis might be associated with the more southerly location of the foraging areas of this population compared to others. Fish were largely represented by the myctophid Gymnoscopelus nicholsi , which occurred in 81.3 % of samples containing otoliths and constituted 76.4 % in numbers and 66.4 % in mass. However, while myctophids may be the dominant fish prey of elephant seals in areas close to the South Shetlands, they would be probably replaced by P. antarcticum as seals migrate towards higher latitudes.

Description: The sea ice cover of the Arctic Ocean has changed dramatically in the last decades, and the resulting consequences for the sea-ice-associated ecosystem remain difficult to assess. Algal aggregates underneath sea ice are of great importance for the ice-associated ecosystem and the pelagic-benthic coupling. However, the frequency and distribution of their occurrence is not well quantified. During the IceArc expedition (ARK-27/3) of RV Polarstern in late summer 2012, we observed different types of algal aggregates floating underneath various ice types in the Central Arctic basins. We investigated the spatial distribution of ice algal aggregates and quantified their biomass, using under-ice image surveys obtained by an upward-looking camera on a remotely operated vehicle. On basin scale, filamentous aggregates of Melosira arctica are more frequently found in the inner part of the Central Arctic pack ice, while rounded aggregates mainly formed by pennate diatoms are found closer to the ice edge, under melting sea ice. On the scale of an ice floe, the distribution of algal aggregates in late summer is mainly regulated by the topography of the ice underside, with aggregates accumulating in dome-shaped structures and at the edges of pressure ridges. The average biomass of the aggregates from our sites and season was 0.1–6.0 mg C m −2 . However, depending on the approach used, differences in orders of magnitude for biomass estimates may occur. This highlights the difficulties of upscaling observations and comparing results from surveys conducted using different methods or on different spatial scales.

Description: Several studies have shown that biostimulation can promote hydrocarbon bioremediation processes in Antarctic soils. However, the effect of the different nutrient sources on hydrocarbon removal heavily depends on the nutrients used and the soil characteristics. In this work, using a sample of chronically contaminated Antarctic soil that was exposed to a fresh hydrocarbon contamination, we analyzed how a complex organic nutrient source such as fish meal (FM) and a commercial fertilizer (OSEII) can affect hydrocarbon biodegradation and bacterial community composition. Both amended and unamended (control) biopiles were constructed and controlled at Carlini Station and sampled at days 0, 5, 16, 30 and 50 for microbiological, chemical and molecular analyses. FM caused a fast increase in both total heterotrophic and hydrocarbon degrading bacterial counts. These high values were maintained until the end of the assay, when statistically significant total hydrocarbon removal (71 %) was detected when compared with a control system. The FM biopile evidenced the dominance of members of the phylum Proteobacteria and a clear shift in bacterial structure at the final stage of the assay, when an increase of Actinobacteria was observed. The biopile containing the commercial fertilizer evidenced a hydrocarbon removal activity that was not statistically significant when compared with the untreated system and exhibited a bacterial community that differed from those observed in the unamended and FM-amended biopiles. In summary, biostimulation using FM in biopiles significantly enhanced the natural hydrocarbon-degradation activity of the Carlini station soils in biopile systems and caused significant changes in the bacterial community structure. The results will be considered for the future design of soil bioremediation protocols for Carlini Station and could also be taken into account to deal with diesel-contaminated soils from other cold-climate areas.

Description: The Antarctic cyanobacterial microflora is one of the main components of the diversity of freshwater phototrophic communities in coastal areas. It is little known according to the modern taxonomic criteria (polyphasic approach). Populations of heterocytous cyanobacteria from Ulu Peninsula, the northern part of James Ross Island, NW Weddell Sea, Antarctica, were therefore reviewed. The identified morphospecies were compared with specimens from other localities in maritime Antarctica, especially from the South Shetland Islands. Ecological demands, morphological variations and, if possible, their phylogenetic positions (based on 16S rRNA gene sequencing) of registered populations were analyzed. Altogether, 11 species of heterocytous cyanoprokaryotes were recognized and studied in detail. These species were dominant in the characteristic habitats, and four novel species were described. All have a restricted endemic Antarctic distribution according to both morphology and 16S rRNA gene analyses. Three species of the genus Calothrix, one species of the genus Dichothrix (Rivulariaceae), and four species from the family Tolypotrichaceae were recognized and documented. Few species from this family belong to the recently recognized and revised genera Dactylothamnos and Hassallia, based on molecular analyses. Nodularia quadrata and two species, taxonomically classified to the genus Hydrocoryne (Nostocaceae), were studied. The complex of the genus Nostoc (especially of N. commune ) exists as numerous morpho- and ecotypes, and it is diverse phylogenetically, morphologically and ecologically, and will be analyzed in special studies. Our study is important for the exact identification of cyanobacterial microflora in Antarctica, which plays a dominant role in the colonization of deglaciated areas.

Description: Until roughly 200 years ago, the Antarctic was untouched by humankind. With ratification of the Antarctic Treaty in 1961, this region was set aside forever for peaceful purposes and as a science preserve. However, Antarctic national programs and tourism activities are growing, increasing the risks of introduction of infectious diseases into wildlife within the Antarctic Treaty area. The immunological naïveté of Antarctic species makes them vulnerable to pathogen’s commonplace in other parts of the world. We review past disease investigations of Antarctic penguins, and outline potential drivers of future disease emergence. Efforts to establish the nature of disease agents in Antarctic penguins, although ongoing since the late 1950s, remain not only patchy and limited in scope but are a lower priority issue for the majority of Antarctic Treaty parties. Pollution, increased connectivity, and global environmental change affecting pathogens and vectors at high latitudes are likely to drive future disease emergence in this region. However, a coordinated plan for disease emergence monitoring is lacking with no formally established programs in place, and surveillance is currently left up to individual interested research groups. We propose possible steps toward the goal of establishing baseline data and tracking infectious diseases in Antarctic penguin species, with the anticipated further increase in human activity and environmental changes in the Antarctic in mind.

Description: Freshwater lakes in the Hudson Bay Lowlands (HBL) area of Ontario are expected to undergo considerable physical, chemical and biological changes related to climatic change; however, the nature of those changes is still very uncertain. As a first step to improve our understanding of fish communities within these subarctic lakes, we aimed to: (a) characterize trophic dynamics of several large-bodied species within three HBL lakes and (b) determine whether trophic dynamics of selected species in the HBL lakes differed from the same species in Southern Ontario lakes. We found that species-specific trophic position and littoral resource reliance varied significantly within and among the HBL lakes of differing biological communities, chemistry and morphometry. Although several significant differences were evident among lakes in the northern and southern regions, we did not find striking consistent differences in trophic dynamics. Based on observations of high variation in trophic position and/or littoral reliance, we can hypothesize that changes in food resources resulting from climatic change would have little impact on most of the large-bodied species.

Description: The food and feeding ecology of albatrosses during the nonbreeding season is still poorly known, particularly with regard to the cephalopod component. This was studied in black-browed Thalassarche melanophris and grey-headed T. chrysostoma albatrosses by analysing boluses collected shortly after adults returned to colonies at Bird Island, South Georgia (54°S, 38°W), in 2009. Based on stable isotopic analyses of the lower beaks, we determined the habitat and trophic level (from δ 13 C and δ 15 N, respectively) of the most important cephalopods and assessed the relative importance of scavenging in terms of the albatrosses’ feeding regimes. Based on lower rostral lengths (LRLs), the main cephalopod species in the diets of both albatrosses was Kondakovia longimana , by frequency of occurrence ( F  〉 90 %), number ( N  〉 40 %) and mass ( M  〉 80 %). The large estimated mass of many squid, including K. longimana , suggests that a high proportion (〉80 % by mass) was scavenged, and that scavenging is much more important during the nonbreeding season than would be expected from breeding-season diets. The diversity of cephalopods consumed by nonbreeding birds in our study was similar to that recorded during previous breeding seasons, but included two new species [ Moroteuthis sp. B (Imber) and ? Mastigoteuthis A (Clarke)]. Based on similarities in LRL, δ 13 C and δ 15 N, the squid consumed may have been from the same oceanic populations or region, with the exception of Taonius sp. B (Voss) and K. longimana , which, based on significant differences in δ 15 N values, suggest that they may have originated from different stocks, indicating differences in the albatrosses’ feeding regimes.

Description: Nitrogen and phosphorus release during decomposition of Notothenia coriiceps (Richardson, 1844) fillets kept in seawater was examined in the laboratory. Amounts of N–NO 2 − , N–NO 3 − , N–NH 4 + , total inorganic nitrogen, total organic nitrogen (TON), total nitrogen (TN), total reactive phosphorus, total organic phosphorus (TOP), and total phosphorus (TP) released during a 5-day exposure were measured. The highest average release (from the standard 100 g fillet wet weight) was typical of TON and TN (2.574 and 2.703 mgN dm −3 , respectively) as well as of TOP and TP (1.526 and 2.648 mgP dm −3 , respectively). The release was observed to be most intense during the initial 120 min of decomposition. As shown by the accumulation rate coefficient, the highest rate of nutrient accumulation in water was typical of organic forms of N and P (0.827 and 1.329, respectively). Organic nitrogen and organic phosphorus accounted for 94 and 54 % of TN and TP release, respectively. In the experiment, nitrogen and phosphorus were released from the fish remains with leached chemicals, which may form important chemical cues for scavengers.