Arctic mission to explore secrets beneath the ice

By STEVE CONNOR

An international project to explore the Arctic Ocean is expected to discover thousands of new species of marine animals that have been cut off from the rest of the world for millions of years.

Scientists say the exploration of the Arctic Ocean - perhaps the least understood body of salt water on earth - is urgent because of the threat that global warming poses for its unique marine life.

A focus of the census will be the Canada Basin, a huge and largely ice-covered underwater hole 3800m deep where life in the depths has remained practically isolated for millennia.

The Arctic exploration project is part of the $1.57 billion Census of Marine Life, an unprecedented collaboration of more than 300 marine scientists from 53 countries with the aim of addressing our ignorance of what lives in the sea.

Since the census began four years ago, more than 500 new species of fish have been identified but scientists believe there could be at least 10 times as many yet to be discovered.

Ron O'Dor, chief scientist for the global census, said the exploration would be undertaken with robot submersibles and sonar equipment, with more traditional techniques deployed from ice-breaking research ships.

"There could be living fossils way down at 3000m that have never been seen before," Dr O'Dor said.

The Arctic Ocean is unusual because much of it is permanently capped with ice and it is surrounded virtually on all sides by land, which reduces the sea's contact with other oceans.

"The entire Arctic Ocean is like an enclosed box with a lid of ice on top. There's no other place in the world like it," he said.

The Canada Basin, a huge region north of the Yukon and Alaska, is a prime target for the exploration programme because so little is known about what lives in its isolated depths, said the Arctic scientists Rolf Gradinger, Russ Hopcroft and Bodil Bluhm of the University of Alaska.

"Given the Canada Basin's long-time separation with little exchange to other deep-sea basins, it will be a particularly interesting area," they said.

A crucial feature of the entire Arctic region is the sea ice that covers much of the surface for most of the year. But a warmer climate has already set in motion a change in the thickness of the Arctic ice cap and the area of the sea that is permanently covered by ice.

Sonar instruments on American and British nuclear-powered submarines have measured a 40 per cent average thinning of the sea ice over the past 30 to 40 years.

Climatologists estimate that the Arctic summer - when more ice melts than freezes - has been extended by an extra five days every decade. The result, they said, was that the annual ebb and flow of ice coverage has led to a persistent shrinkage, and scientists estimate there could be a totally ice-free Arctic summer as soon as 2080.

A lack of thick ice is already having an impact on local wildlife. Polar bears, for instance, are being starved as a result of having to swim longer distances between ice floes when they go hunting for seals in spring and summer.

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