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Antarctica: The Southern Ocean

Antarktis Sørishavet Kjartan Mæstad

RV G.O. Sars in the Southern Ocean

Photo: Kjartan Mæstad / IMR

The Southern Ocean surrounds the continent of Antarctica. It is a closed ecosystem, clearly separated from the surrounding oceans by the polar front. The front forms where the icy Antarctic waters meet warmer waters from the north, “closing off” the ecosystem.

The Southern Ocean can be split into three different zones: an outer, ice-free zone; a middle zone; and an inner zone with permanent ice cover around Antarctica. There is most activity in the middle zone, which is where the krill live.

Krill is a keystone species in the Southern Ocean. It is the most important food source for fish, octopuses, penguins, seals and whales. In the Southern Ocean, the rungs in the food chain are unusually far apart. This means that small krill eat microscopic phytoplankton, and are themselves eaten by enormous whales.

Norway is the country with the biggest commercial krill fishery in the Antarctic. That’s why our country has a responsibility to ensure that the catch is sustainable and doesn’t harm the ecosystem. The IMR is helping by performing research and carrying out monitoring activities, in order to provide the information needed to properly manage the krill stocks. We present our results, including analyses and reports, through various international forums.