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Tromso, Norway

The Norwegian Polar Institute is Norway's national institution for polar research. It is run under the auspices of the Norwegian Ministry of Environment. The institute organizes expeditions to the Arctic and Antarctic regions and runs a research station at Ny-Ålesund. Its offices are in Tromsø and Svalbard, together with a research station in Queen Maud Land, and employs approximately 150 persons. It has the responsibility to enforce international treaties regarding Antarctic activities by Norwegian citizens or corporations. The institute was founded as Norges Svalbard- og Ishavsundersøkelser by Adolf Hoel in 1928. Wikipedia.

Schultner J.,Norwegian University of Science and Technology | Schultner J.,Norwegian Polar Institute | Schultner J.,U.S. Geological Survey
Proceedings. Biological sciences / The Royal Society | Year: 2013

Life-history strategies describe that 'slow'- in contrast to 'fast'-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events. Source

Ji R.,Woods Hole Oceanographic Institution | Jin M.,University of Alaska Fairbanks | Varpe O.,Norwegian Polar Institute | Varpe O.,Akvaplan Niva
Global Change Biology | Year: 2013

Arctic organisms are adapted to the strong seasonality of environmental forcing. A small timing mismatch between biological processes and the environment could potentially have significant consequences for the entire food web. Climate warming causes shrinking ice coverage and earlier ice retreat in the Arctic, which is likely to change the timing of primary production. In this study, we test predictions on the interactions among sea ice phenology and production timing of ice algae and pelagic phytoplankton. We do so using the following (1) a synthesis of available satellite observation data; and (2) the application of a coupled ice-ocean ecosystem model. The data and model results suggest that, over a large portion of the Arctic marginal seas, the timing variability in ice retreat at a specific location has a strong impact on the timing variability in pelagic phytoplankton peaks, but weak or no impact on the timing of ice-algae peaks in those regions. The model predicts latitudinal and regional differences in the timing of ice algae biomass peak (varying from April to May) and the time lags between ice algae and pelagic phytoplankton peaks (varying from 45 to 90 days). The correlation between the time lag and ice retreat is significant in areas where ice retreat has no significant impact on ice-algae peak timing, suggesting that changes in pelagic phytoplankton peak timing control the variability in time lags. Phenological variability in primary production is likely to have consequences for higher trophic levels, particularly for the zooplankton grazers, whose main food source is composed of the dually pulsed algae production of the Arctic. © 2012 Blackwell Publishing Ltd. Source

Descamps S.,Norwegian Polar Institute
PLoS ONE | Year: 2013

The Arctic is rapidly warming and host-parasite relationships may be modified by such environmental changes. Here, I showed that the average winter temperature in Svalbard, Arctic Norway, explained almost 90% of the average prevalence of ticks in an Arctic seabird, the Brünnich's guillemot Uria lomvia. An increase of 1°C in the average winter temperature at the nesting colony site was associated with a 5% increase in the number of birds infected by these ectoparasites in the subsequent breeding season. Guillemots were generally infested by only a few ticks (≤5) and I found no direct effect of tick presence on their body condition and breeding success. However, the strong effect of average winter temperature described here clearly indicates that tick-seabird relationships in the Arctic may be strongly affected by ongoing climate warming. © 2013 Sébastien Descamps. Source

Hudson S.R.,Norwegian Polar Institute
Journal of Geophysical Research: Atmospheres | Year: 2011

A simple method for estimating the global radiative forcing caused by the sea ice-albedo feedback in the Arctic is presented. It is based on observations of cloud cover, sea ice concentration, and top-of-atmosphere broadband albedo. The method does not rely on any sort of climate model, making the assumptions and approximations clearly visible and understandable and allowing them to be easily changed. Results show that the globally and annually averaged radiative forcing caused by the observed loss of sea ice in the Arctic between 1979 and 2007 is approximately 0.1 W m-2; a complete removal of Arctic sea ice results in a forcing of about 0.7 W m-2, while a more realistic ice-free summer scenario (no ice for 1 month and decreased ice at all other times of the year) results in a forcing of about 0.3 W m-2, similar to present-day anthropogenic forcing caused by halocarbons. The potential for changes in cloud cover as a result of the changes in sea ice makes the evaluation of the actual forcing that may be realized quite uncertain since such changes could overwhelm the forcing caused by the sea ice loss itself, if the cloudiness increases in the summertime. Copyright 2011 by the American Geophysical Union. Source

We investigated the changes in absorption and spectral slopes of colored dissolved organic matter (CDOM) using a data set of salinity, δ 18O and CDOM absorption in Hudson Bay. Following the fraction of river water (determined with salinity and δ 18O tracers) one can track the changes in terrestrial CDOM optical properties with mixing and removal, as salinity cannot alone be used in waters with significant influence from sea-ice melt. CDOM in Hudson Bay was controlled by terrestrial inputs, in contrast to adjacent Hudson Strait. CDOM absorption was removed significantly, likely due to photobleaching. There was no or negligible indication of absorption removal during initial estuarine mixing, in agreement with earlier studies. Of the many absorption spectral slope (S) parameters that have been used as proxies for CDOM dynamics, the ones at shorter wavelengths proved the best indicators for absorption removal by photobleaching. Increase in absorption spectral slopes at 275 to 295 (S 275-295) and 290 to 350nm (S 290-350) are strongly correlated with the apparent removal of CDOM absorption. S 275-295 and S 290-350 in combination with spectral slopes and ratios at other wavelength intervals, which are sensitive to other processes and sources, can potentially reveal more information about CDOM origin and dynamics than a single slope alone. © 2012 Elsevier B.V. Source

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