Page 21 - living-ice

The sea ice is a dynamic lid
A myriad of animals and algae live on and in the sea ice. The ice also has an impact on the habitats of animals and plants that live in the water below it. The Arctic Ocean is a giant basin surrounded by shelf and the sea ice forms a dynamic lid over it. The ice thickness, the size of the ice oes and the amount of snow on the ice all play an important role in determining how much light gets through to the algae in the ice and in the water below.
This ice lid forms over the Arctic Ocean when the water freezes in autumn and winter. It reaches its maximum extent in March or April before the solar irradiation increases, the freezing slows and the processes that fragment and melt the ice take over. The ice oes break up, light penetrates in between the drifting ice oes and melt ponds on the sea ice function like windows that let light through the ice. The outer edges of sea ice cover move northward throughout the spring and summer until the sea ice reaches its minimum extent in September. Throughout the year, the wind determines how densely the sea ice is packed, which areas have consolidated ice and which areas have open water. Consequently, the ice conditions are constantly changing.
PHOTO: Peter leopold, Norsk Polarinstitutt