Page 17 - living-ice

ILL.: REIBO
Old, but still young
The Arctic Ocean has been covered by sea ice for several hundred thousand years. However, even the oldest ice oes are less than 10 years old because they continually drift and melt as soon as they drift out of the Arctic Ocean. Nansen’s Fram expedition of 1893–1896 was based on an experiment to study the impact of ocean currents on the ice. Nansen let his ship, the Fram, freeze into the pack ice north of the Siberian coast to drift with the ice. Three and a half years later, the Fram drifted out of the sea ice between Svalbard and Greenland in what is now known as the Fram Strait. Nansen had thereby demonstrated that the ice drifted westward with the ocean currents, proving what is now called the Transpolar Drift.
The Transpolar Drift is one of two major wind-driven ocean currents that transport sea ice in the Arctic Ocean. It moves the sea ice from the coast of Siberia across the Arctic Ocean, past Svalbard and out through the Fram Strait. It is estimated that the Transpolar Drift transports up to 4 million tonnes of biomass (live animals and algae) into the Atlantic Ocean annually. The other major current is also a wind-driven ocean current called the Beaufort Gyre. This large gyre moves clockwise in a circular formation in the Beaufort Sea and Canada Basin north of Greenland, Canada and Alaska. The Beaufort Gyre has formed an expanding dome of fresh water on the surface. The gyre is named after the Irish naval of cer Sir Frances Beaufort, who also gave his name to the wind scale we still use today.