Sea ice: a habitat for specialists

Dr Ilka Peeken, marine biologist at the Alfred Wegener Institute.


Polar regions


Sea Ice

Climate change is especially putting the polar regions under pressure. Environmental changes in the Arctic result primarily from the decline in the area of sea ice and the decrease in its thickness, since sea ice itself represents a fundamentally important habitat. Specially adapted flora and fauna live in the ice and on its underside, and their key species are different in the Arctic compared to the Antarctic.

In both polar regions, the species communities of the sea ice play a crucial role for other living organisms in the water column. The ice algae living in the ice are adapted to the extremely low light conditions during the polar night. They already form algal blooms at the beginning of the summer season and thus provide an initial food source for krill and other zooplankton, which are in turn fed on by fish, whales and other predators.

Changes in ice growth – in terms of its thickness and extent alike – are upsetting this delicate balance. At the AWI, we’re investigating how the altered environmental conditions affect the biodiversity of sea-ice organisms; the possible consequences these changes have for the entire ecosystem; and what the implications are for the global carbon budget.

Plastic pollution in the oceans is a current and growing problem, since every year several million metric tons of plastic find their way from the land to the water. Plastic particles are broken down in the ocean by sunlight, temperature fluctuations, mechanical abrasion and wave action into small fragments known as microplastics. These tiny particles can then easily be ingested by sea life and accumulate in the food chain, as far up as fish. We have found high levels of microplastic in sea ice. The aim of our research is now to gain a better understanding of microplastic pollution in sea ice and to investigate its consequences for organisms in the sea ice, and for the adjacent ecosystem.