Environment News Service (ENS)

Arctic Ocean Ice Thinner By Half in Six Years

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Source: Environment News Service (ENS)

BREMERHAVEN, Germany, September 14, 2007 (ENS) - Large areas of Arctic sea ice are only one meter thick this year, about 50 percent thinner than they were in the year 2001, according to measurements taken by 50 scientists on board the research ship Polarstern. The international team is conducting research on sea ice in the central Arctic Basin.'The ice cover in the North Polar Sea is dwindling, the ocean and the atmosphere are becoming steadily warmer, the ocean currents are changing,' said chief scientist Dr. Ursula Schauer from the Alfred Wegener Institute for Polar and Marine Research, who has been aboard the Polarstern for two and a half months.

Schauer is currently in the Arctic, underway with scientists from Germany, Russia, Finland, the Netherlands, Spain, the United States, Switzerland, Japan, France and China, where they are investigating ocean and sea ice conditions.

'We are in the midst of phase of dramatic change in the Arctic, and the International Polar Year 2007/08 offers us a unique opportunity to study this dwindling ocean in collaboration with international researchers,' said Schauer.

The thickness of the Arctic sea ice has been shrinking since 1979, and on this trip oceanographers have found a particularly high concentration of melt-water in the ocean and a large number of melt-ponds.

According to the latest computer models, says Schauer, the Arctic could be ice free in less than 50 years, in case of further warming. She says this may cause the extinction of many life forms that are adapted to the Arctic habitat.

Sea ice biologists from the Institute of Polar Ecology at Germany's University of Kiel are studying the animals and plants living in and beneath the ice, using the Polarstern voyage as an opportunity to investigate the threatened ecosystem.

Tiny zooplankton are at the base of the food chain for many marine creatures, and are an important indicator of ecosystem health. 'The deposits found on the ocean floor of the North Polar Sea read like a diary of the history of climate change for the surrounding continents. Through sediment cores, the scientists may be able to unlock the key to the glaciation of northern Siberia,' Schauer says.

Oceanographers on board the Polarstern are investigating the composition and circulation of the water masses, physical characteristics of sea ice and transport of biological and geochemical components in ice and seawater.

Sea ice ecosystems in the seawater and on the ocean floor are also a focus of investigations. Scientists will take sediments from the ocean floor to reconstruct the climatic history of the surrounding continents.

The study area stretches from the shelves of the Barents Sea, the Kara Sea and the Laptev Sea, across Nansen and Amundsen bays up to Makarow Bay.

Between Norway and Siberia and up to the Canadian Bay the scientists have taken temperature, salinity, and current measurements at more than 100 places.

The Arctic Ocean currents are an important part of global ocean circulation, Schauer explains. Warm water masses flowing in from the Atlantic are changed in the Arctic through water cooling and ice formation, and sink to great depths.

The large rivers of Siberia and North America transport huge amounts of freshwater to the Arctic. Schauer says the freshwater appears to function as an insulating layer, controlling the transfer of warmth between the ocean, the ice and the atmosphere.

The deployment of a new titanium measuring system will allow contamination-free sample collection of trace elements for the first time. Members of the expedition will be able to measure trace elements from Siberian rivers and shelf areas that are being pushed towards the Atlantic through a phenomenon Schauer calls polar drift.

Oceanographic measuring buoys were set out in all regions of the Arctic Ocean for the first time during this International Polar Year. They are drifting freely in the Arctic Ocean collecting data on currents, temperature, and salt content of the seawater which is sent back to the scientists via satellite.

To follow the circulation patterns in winter, oceanographic measuring buoys will be attached to ice floes, and continuous measurements will be taken while they float along with the ice. Scientists will receive these data too via satellite.

The Alfred Wegener Institute for Polar and Marine Research is one of the 15 research centers of the Helmholtz Association, Germany's largest research institution. The 26,500 Helmholtz employees produce scientific results in six research fields with an annual budget of 2.3 billion euros.

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