Page 5 - living-ice

The Arctic pulse
The seasons in the Arctic Ocean are controlled by light. The sea ice in the Arctic Ocean grows in extent and thickness during the winter darkness of the polar night. Summer on the other hand is characterized by intense sunlight and the arrival of warm water from the south. Large amounts of the sea ice melt during this period. The melting occurs both at the surface as well as under water from below. The sea temperature has increased signi cantly in recent decades so the summer melt now starts earlier and happens more rapidly than previously. Since the melt season now lasts longer, the ice has less time to grow in extent and thickness again before the next melt season starts. The result of this is that the sea ice extent has decreased by around 40% over the past 30 years. Researchers now predict that within a few decades the entire ice cover in the Arctic Ocean will disappear during the melt season.
An important question for the researchers in Arctic Seasonal Ice Zone (Arctic SIZE) is what impacts the increasing melting of sea ice has on the life in the Arctic Ocean. To understand these impacts, the researchers need to know what species live in the Arctic Ocean and in the sea ice and study what they do. Some of these organisms are found nowhere else on earth so it is easy to imagine that the unique Arctic eco- systems will be severely affected if the sea ice disappears.
Average ice cover for the last 10 years (1 January to 12 December)
ILL. Wayne Chan, University of Manitoba