Abstract: In situ observations show that snow accumulation is ∼10% larger 25 km north than south of the summit of Dome C on the east antarctic plateau. The mean wind direction is southerly. Although a slight slope-related diverging katabatic flow component is detectable, the area is an essentially flat (∼10 m elevation change or less) homogeneous snow surface. The European Center for Medium-range Weather Forecasts meteorological analyses data reproduce a significant accumulationgradient and suggest that 90% of the the mean accumulation results from the 25% largest precipitation events. During these events, air masses originate from coastal areas in the north rather than from inland in the south. Radiative cooling condensation occurs on the way across the dome and as the moisture reservoir is depleted less snow is dumped 25 km south than north, withlittle direct impact from the local (50-km scale) topography. Air masses are warmer on average, and warmer north than south, when originating from the coast. This marginally affects the mean temperature gradients. The moisture gradients are more affected because moisture is nonlinearly related to temperature: the mean atmospheric moisture is larger north than south.Significant meteorological and hydrological gradients over such relatively small distances (50 km) over locally flat region may be an issue when interpreting ice cores: although cores are drilled at the top of domes and ridges where the slopes andelevation gradients are minimal, they sample small surfaces in areas affected by significant eteorological and hydrologicalspatial gradients.

Abstract: Microplastics have been reported everywhere around the globe. With very limited human activities, the Arctic is distant from major sources of microplastics. However, microplastic ingestions have been found in several Arctic marine predators, confirming their presence in this region. Nonetheless, existing information for the Arctic remains scarce, thus there is an urgent need to quantify the contamination of marine waters in this part of the world. In this context, we studied microplastic abundance and composition within the zooplankton community off East Greenland. For the same area, we concurrently evaluated microplastic contamination of little auks (Alle alle), an Arctic seabird feeding on zooplankton while diving between 0-50 m. The study took place off East Greenland in July 2005 and 2014, under strongly contrasted sea ice conditions. Among all samples, 97.2 % of the debris found were filaments. Despite the remoteness of our study area, microplastic abundances were comparable to those of other ocean basins, with 0.99 ± 0.62m-3 in the presence of sea-ice (2005), and 2.38 ± 1.11m-3 in the nearby absence of sea-ice (2014). These results suggest that sea ice can represent a sink for microplastic particles, which are subsequently released to the water column upon the melting. Crucially, all birds studied had eaten plastic filaments, and little auks collected significantly higher levels of microplastics compared to background levels with 9.99 and 8.99 pieces per chick meal in 2005 and 2014, respectively. Importantly, we also demonstrated that little auks more often take light colored microplastics, rather than darker ones, strongly suggesting an active contamination with birds mistaking microplastics for their natural prey. Overall, our study stresses the great vulnerability of Arctic marine species to microplastic pollution in a warming Arctic, where sea-ice melting is expected to release vast volumes of trapped debris.

Abstract: Individual specialization is widespread among wild populations. While its fitness consequences are central in predicting the ecological and evolutionary trajectories of populations, they remain poorly understood. Long-term individual foraging specializations occur in male Antarctic (Arctocephalus gazella) and Australian (A. pusillus doriferus) fur seals. Strong selective pressure is expected in these highly dimorphic and polygynous species, raising the question of the fitness payoffs associated with different foraging strategies. We investigated the relationship between individual isotopic niche (a proxy of foraging specialization), body size and condition, and an index of reproductive success (harem size) in territorial males. Individuals varied greatly in their skin and fur isotopic values reflecting a range of foraging strategies within the two populations. However, in both species, isotopic niche was not correlated to body size, condition or mating success (R2/ρ < 0.06). Furthermore, no foraging niche was predominant in either species, which would have indicated a substantial long-term fitness benefit of a particular strategy via a higher survival rate. These results suggest that the fitness consequences of a foraging strategy depend not only on the quality of prey and feeding habitat but also on an individual's hunting efficiency and skills.

Abstract: This paper reviews the major contributions made by Norwegian scientists to Arctic environmental sciences since　the 1880s.The review begins with the first International Polar Year (IPY) in 1882-83. It then considers the 1890s to 1920s with　the scientific expeditions focusing on ocean and sea ice conditions of Nansen, Amundsen and H. Sverdrup, and the mapping of　the Queen Elizabeth Islands by Otto Sverdrup and colleagues. The period from 1911 to the mid-1920s also witnessed annual　expeditions to Svalbard led by Adolf Hoel. The 1930s to 1945 period encompassed the Second International Polar Year when　Arctic weather stations were established or maintained. The time interval post-World War II to 2000 witnessed major advancesmade possible by technical and organizational innovations. The establishment of the Norwegian Polar Institute in 1948 led to　extensive research on the glaciers and snow cover in the Svalbard archipelago and to oceanographic and sea ice research in the　Barents Sea and Arctic Ocean. Remote sensing methods began to be widely used from the 1980s. The new millennium saw theundertaking of the third IPY and a shift to multinational projects. New fields such as ocean–ice–atmosphere variability became active and there was much attention to high-latitude climate change in the context of global warming.