A diet with ice: how does the food web underneath the ice of the polar oceans work?

Published on
November 20, 2018

Life in the polar oceans is under pressure due to global warming. Marine Biologist Fokje Schaafsma went to the Arctic and Antarctic regions to study organisms underneath the sea ice, where often only small scale research is being done. With her thesis she contributes to the understanding of the food webs in these areas.

Floating ice covers large parts of the oceans in the north- and south pole areas. To better understand the food webs and ecosystems of the polar areas, researchers collect samples from underneath the sea ice. This is not easy, as it is a place that is hard to reach. With the SUIT (Surface and Under Ice Trawl), a specifically designed net, Schaafsma and her colleagues collect small animals from underneath the ice. The stomach- and energy content of these animals are analysed to, for example, increase the understanding of patterns in feeding behaviour.

Life underneath the ice

Algae, unicellular organisms, copepods and amphipods live in and underneath the sea ice. These organisms turn out to be an essential food source for e.g. polar cod (north) and Antarctic krill (south), two species that are key in the polar food webs. Antarctic krill and polar cod serve, in turn, as a food source for birds, seals and whales in the polar areas. In addition, the sea ice has a function as a platform for reproduction and as a shelter against predators or currents.

Credits: Jan Andries van Franeker
Credits: Jan Andries van Franeker

With the findings of her PhD research, Schaafsma contributes to the understanding of life in ice covered oceans. Her research emphasizes the essential role of ice for organisms in the polar regions. Global warming may therefore form a threat for the ecosystems in these areas.

The necessity of a sustainable management for nature conservation and fisheries in the polar regions is also emphasized by Schaafsma: “In the Arctic region, the sea ice is melting very fast, resulting in fish species expanding their distribution northward. In addition, the region becomes more accessible because the sea ice does not obstruct ships anymore. It is therefore important to better understand the role of climate change”.

On the 16th of November dr. Fokje Schaafsma defended her PhD thesis 'Life in the polar oceans: the role of sea ice in the biology and ecology of marine species' at Wageningen University & Research.