Scientists in the project, led from the University of Alaska, plan to use robot submarines and sonar to track down life in the chilly Arctic Ocean where they say many species may be at risk from global warming.

"This is the world's refrigerator where change has happened far more slowly than in other oceans," said researcher Russ Hopcroft at the University of Alaska, saying the census could easily double the number of species known in the Arctic.

The research is part of a $1 billion, 10-year global Census of Marine Life (CoML) funded by governments, companies and private donors. The Arctic survey got a $600,000 start-up grant from the private U.S. Alfred Sloan foundation yesterday.

Ron O'Dor, chief scientist of the 53-nation CoML, speculated that Arctic waters might hide creatures known only from fossils, such as trilobites that flourished 300 million years ago. The trilobites looked like over-sized modern woodlice.

He said it might find new types of jellyfish, giant squid or more humble plankton and algae in the barely surveyed ocean. "And this may be a last window of opportunity to study the Arctic because of climate change," he said.

INVASIVE SPECIES?

More southerly species may invade Arctic waters if the polar icecap melts while increased shipping could accidentally introduce new creatures to the region in ballast water and disrupt the pristine ecology, he said.

U.N. models say that the Arctic could be largely ice-free in summer by 2100 because of global warming, blamed mostly on emissions of gases from cars, power plants and factories.

About 7,000 species are already known from Russian-led surveys in the Arctic Ocean. "Anything that's fast enough to move out of the way may have been missed by previous surveys," focused on sampling water or sediments, Hopcoft said.

Arctic waters, about zero degrees Celsius (32 Fahrenheit) year-round, are unlikely to hide unknown commercial stocks of fish.

The 3,800-meter Canada Basin is a mystery because it is cut off from deep waters in the Pacific by the 70-meter deep Bering Strait and from currents from the more distant North Atlantic by 1,400-meter deep ridges and straits.

"This water has been isolated more than any other part of the world's oceans, including around Antarctica," said Bodil Bluhm of the University of Alaska.