Abstract: The Patagonian slope is the region where Subantarctic waters and bathymetry give raise to physical and ecological processes that support a rich biodiversity and a large-scale industrial fisheries. Unique among the species that depend on this region is the deep diving southern elephant seal, Mirounga leonina. We report here on changes in the foraging behavior of a female seal explained by the combined effect of a cold and high salinity water mass and a decrease in surface chlorophyll-a concentration. Behavioral and oceanographic data from about 5000 profiles of temperature, conductivity, pressure, light and prey encounters were collected within an area ranging 59.5–61°W and 46–47.5°S, at depths of 300–700 m, on the Patagonian slope, during November–December 2018. A decrease in temperature (0.15 °C) and an increase in salinity (0.03) was found below the mixed layer, during December. Light data revealed a significant increase of irradiance in December (almost reaching the ocean bottom) associated with a decrease of chlorophyll-a in the upper levels. Concomitantly, the seal had a different diving behavior in December, foraging near the surface at night and close to the bottom during daylight hours. Also, the seal doubled the prey capture attempts in December compared to November. This study reveals the importance of ocean physical properties on seal's diving and foraging behavior, and how this changes, although small, can impact on seals diet and body composition during their post-breeding trips.

Abstract: Light-absorbing carbonaceous aerosols emitted by biomass or fossil fuel combustion can contribute to amplifying Arctic climate warming by lowering the albedo of snow. The Svalbard archipelago, being near to Europe and Russia, is particularly affected by these pollutants, and improved knowledge of their distribution in snow is needed to assess their impact. Here we present and synthesize new data obtained on Svalbard between 2007 and 2018, comprising measurements of elemental (EC) and water-insoluble organic carbon (WIOC) in snow from 37 separate sites. We used these data, combined with meteorological data and snowpack modeling, to investigate the variability of EC and WIOC deposition in Svalbard snow across latitude, longitude, elevation and time. Overall, EC concentrations (CsnowEC) ranged from <1.0 to 266.6 ng g−1, while WIOC concentrations (CsnowWIOC) ranged from <1 to 9426 ng g−1, with the highest values observed near Ny-Ålesund. Calculated snowpack loadings (LsnowEC, LsnowWIOC) on glaciers surveyed in spring 2016 were 0.1 to 2.6 mg m−2 and 2 to 173 mg m−2, respectively. The median CsnowEC and the LsnowEC on those glaciers were close to or lower than those found in earlier (2007–2009), comparable surveys. Both LsnowEC and LsnowWIOC increased with elevation and snow accumulation, with dry deposition likely playing a minor role. Estimated area-averaged snowpack loads across Svalbard were 1.1 mg EC m−2 and 38.3 mg WIOC m−2 for the 2015–2016 winter. An ∼11-year long dataset of spring surface snow measurements from the central Brøgger Peninsula was used to quantify the interannual variability of EC and WIOC deposition in snow. In most years, CsnowEC and CsnowWIOC at Ny-Ålesund (50 m a.s.l.) were 2–5 times higher than on the nearby Austre Brøggerbreen glacier (456 m a.s.l.), and the median EC/WIOC in Ny-Ålesund was 6 times higher, suggesting a possible influence of local EC emission from Ny-Ålesund. While no long-term trends between 2011 and 2018 were found, CsnowEC and CsnowWIOC showed synchronous variations at Ny-Ålesund and Austre Brøggerbreen. When compared with data from other circum-Arctic sites obtained by comparable methods, the median CsnowEC on Svalbard falls between that found in central Greenland (lowest) and those in continental sectors of European Arctic (northern Scandinavia, Russia and Siberia; highest), which is consistent with large-scale patterns of BC in snow reported by surveys based on other methods.

Abstract: The Svalbard archipelago, located at the Arctic sea-ice edge between 74 and 81∘ N, is ∼60 % covered by glaciers. The region experiences rapid variations in atmospheric flow during the snow season (from late September to May) and can be affected by air advected from both lower and higher latitudes, which likely impact the chemical composition of snowfall. While long-term changes in Svalbard snow chemistry have been documented in ice cores drilled from two high-elevation glaciers, the spatial variability of the snowpack composition across Svalbard is comparatively poorly understood. Here, we report the results of the most comprehensive seasonal snow chemistry survey to date, carried out in April 2016 across 22 sites on seven glaciers across the archipelago. At each glacier, three snowpits were sampled along the altitudinal profiles and the collected samples were analysed for major ions (Ca2+, K+, Na+, Mg2+, NH4+, SO42-, Br−, Cl−, and NO3-) and stable water isotopes (δ18O, δ2H). The main aims were to investigate the natural and anthropogenic processes influencing the snowpack and to better understand the influence of atmospheric aerosol transport and deposition patterns on the snow chemical composition. The snow deposited in the southern region of Svalbard is characterized by the highest total ionic loads, mainly attributed to sea-salt particles. Both NO3- and NH4+ in the seasonal snowpack reflect secondary aerosol formation and post-depositional changes, resulting in very different spatial deposition patterns: NO3- has its highest loading in north-western Spitsbergen and NH4+ in the south-west. The Br− enrichment in snow is highest in north-eastern glacier sites closest to areas of extensive sea-ice coverage. Spatial correlation patterns between Na+ and δ18O suggest that the influence of long-range transport of aerosols on snow chemistry is proportionally greater above 600–700 m a.s.l.

Abstract: Group-living is associated with both fitness benefits and costs for animals. In seabird colonies, spatial heterogeneity in social density and other environmental parameters may affect the quality of breeding territories. For instance, in king penguins, increased conspecific density has been correlated with increased stress hormone levels and increased energy expenditure in individual birds, suggesting a cost of colonial breeding. We unravelled the influences of early (genetic and early maternal effects) and rearing environments on chick growth trajectories, stress physiology and survival. Our results suggest that the rearing social environment (rather than biological background) can influence chicks’ phenotype, growth and survival. Especially, chicks reared in high density areas of the colony showed increased weight gain and survival probabilities. These results suggest either a difference in terms of parental quality between individual breeding at high and low social densities or a difference in chick’s competitiveness due to their early life social environment.

Abstract: Coloniality is associated with various benefits and costs for animals affecting their fitness. Breeding colonies are heterogeneous both in terms of physical and social parameters, thus, breeding territories are of different quality relative to their location within the colony. In king penguins, increased conspecific density has been correlated with increased stress level in individual birds, suggesting a cost of colonial breeding. We used a cross-fostering approach to question the relationship linking breeding location, phenotype and reproduction success. We crossfostered eggs shortly after laying within and between high-and low-density colony areas. This design allowed us to unravel the influences of early genetic and maternal effects together with rearing environments on chick growth trajectories, stress physiology and survival. We tested whether chick phenotype is determined at birth to match their early environment or if higher social density conferred an advantage for reproduction.