International polar day, 21 September 2007: Sea ice

The first of a series of International Polar Days focus on the snow and ice in the Arctic and Antarctic regions. Alarming discoveries about reduced sea ice have recently been reported by scientists, and updated reports are expected over the next several weeks.

The International Polar Year 2007–2008 joins 50,000 researchers from more than 60 countries in an effort to learn more about our polar regions. This autumn, two large research programmes, DAMOCLES and SIPEX, investigate opposite poles.

DAMOCLES – investigating changes in polar snow and ice
Five research ships with scientists from 16 countries are currently in the Arctic performing groundbreaking research to better understand climate changes.

The European Union Programme DAMOCLES (Developing Arctic Modelling and Observing Capabilities for Long-term Environment Studies), which is part of the International Polar Year, is concerned with the potential for a significantly reduced sea ice cover, and the impacts this might have on the environment and human activities, both regionally and globally.

Polarstern reports: The sea ice has halved

Large areas of the Arctic sea ice are now only one metre deep, which means the thickness of the ice has halved since 2001, initial findings from the research ship Polarstern show.

Fifty scientists are on board Polarstern for two and a half months. Their main task is to investigate the sea ice in the central Arctic. I addition to thinning ice sheets, they have also discovered that ocean currents and community structures are changing.

“The ice cover in the North Polar Sea is dwindling, the ocean and the atmosphere are becoming steadily warmer and the currents are changing,” said expedition leader Dr. Ursula Schauer from the Alfred Wegener Institute.

“We are in the midst of a phase of dramatic change in the Arctic, and the International Polar Year 2007-2008 offers us a unique opportunity to study this dwindling region in collaboration with international researchers,” said Schauer who is currently in the Arctic.

The scientists have measured temperature, saltiness and currents at over one hundred locations. The primary results show that the water coming in from the Atlantic is colder than in previous years. The temperature and saltiness of the Arctic deep sea are also slowly changing. The changes are small, but involve enormous volumes of water.

The research
Oceanographers on board the ship are investigating the composition and circulation of the water masses, physical characteristics of sea ice, and transport of biological and geochemical components in sea water. They have found a particularly high concentration of melt water in the ocean and a large number of melt ponds.

Scientists will take sediments from the ocean floor in order to reconstruct the climatic history of the surrounding continents. 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.

Sea ice biologists from the Institute of Polar Ecology at the University of Kiel are investigating the threatened ecosystem under the ice. According to new models, the Arctic will be ice free in less than fifty years. This may cause the extinction of many organisms that are adapted to this habitat.

The tools
During the International Polar Year 2007-2008, oceanographic measuring buoys were set out for the first time. They are able to drift freely in the Arctic Ocean while collecting data on currents, temperature and saltiness of the sea water. The buoys will continously collect data and send them back to the scientists via satellite. The deployment of a new titanium measuring system will allow contamination free sample collection of trace elements from Siberian rivers.

The expedition is lead by the German research institute Alfred Wegener Institute for Polar and Marine Research and is supported by DAMOCLES.