Background: Arctic marine ecosystems

The ecosystem of the Barents Sea is a unique, complex food web that is fashioned by its distinctive plankton, animal species and environmental factors. Wrapped in ice and snow, plunged into total darkness, blizzard winds, and cold winters, the Barents Sea is on of the more inaccessible and yet beautiful environments. Life here endures great extremes in light and temperature known, yet the Barents Sea is overflowing with life.

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Arctic comb jelly (Photo: Peter Leopold)

But what regulates the biological productivity in the Barents Sea?

Ice thickness, snow cover, and melt water pond strongly effect the light budget in and under the ice, thus also affecting productivity in ice-associated ecosystems. These include ice algae, ice fauna and microbes. Arctic zooplankton use ice algae as an early source of food after the polar night, and the distribution of polar cod and capelin is linked to the ice edge. The zone along the ice adge is a vital food source for seals, polar bears and seabirds.

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Little Auks of the coast of Svalbard (Photo: Ann E. Lennert).

A shrinking ice cover change the animal and plant communities and their habitats, and impacts productivity in the water masses. This may change the transfer of contaminants through the food web, due to altered prey community, uptake and effects.

Predicting the future change in the ecosystem of the Barents Sea requires knowledge about what determines the structure and robustness of the food  web. There are large knowledge gaps in the understanding of microbial organisms and the processes they are involved in.

How can the structure of the food web affect transfer of energy and biomass between trophic levels?

Likewise, we have  have too little knowledge about how the spatial distribution of species, communities and food webs respond to changes in climate, biological factors (such as invasive species) and human impacts (e.g. fishing, shipping, oil and gas exploration). We need a better understanding of how human impacts and climate affect ecosystem structure and function, and how this in turn impacts the systems stability, productivity and robustness. These are important elements in future management of the marine resources of the northern Barents Sea.

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(Illustration: Ann E. Lennert).