Climatic Influence on Energy Flow and Trophic Structure in Arctic Marine Ecosystems

Sea ice directly or indirectly mediates many of the physical, chemical, and biological processes of Arctic marine ecosystems, especially on the shelves where benthic and pelagic systems are extensively coupled. Ice is also one of the features of the Arctic seas that is most profoundly affected by local, regional, and global climate, varying on scales ranging from days to millennia. Therefore, sea ice can be seen as a lever through which changes in climatic regimes can have far-reaching consequences on the structure and function of Arctic marine ecosystems.

Using this rationale, we test the hypothesis that changing ice conditions associated with different climatic regimes drives primary production on the northern Svalbard shelf through different dominant sources (ice algae vs. phytoplankton). We propose that such variation in the dominant source pathways of primary production has concomitant effects on both the pelagic and benthic systems, as well as the trophic pathways by which they are coupled. We use field measurements and laboratory analyses to test a series of working hypotheses related to the primary producers, zooplankton, and benthic components of northeast Spitsbergen.

Our analytical toolbox includes stable isotope ratios (δ13C and δ15N) in order to identify different carbon sources and trophic levels, respectively, and fatty acid signatures to identify food web linkages. Ultimately, this study aims to provide some insight into the energetic pathways and trophic structure of this ecosystem and its stability versus sensitivity in the face of predicted future climate changes.

Financed by the Norwegian Research Council: Project #150356-S30, “On Thin Ice? Climatic Influence on Energy Flow and Trophic Structure in Arctic Marine Ecosystems”

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