Antarctic ice melt reveals exotic creatures


Feb 26, 2007

An orange sea star is one of the unusual creatures found by an Antarctic expedition.

WASHINGTON (Reuters) -- Spindly orange sea stars, fan-finned ice fish and herds of roving sea cucumbers are among the exotic creatures spied off the Antarctic coast in an area formerly covered by ice, scientists reported Sunday.

This is the first time explorers have been able to catalog wildlife where two mammoth ice shelves used to extend for some 3,900 square miles over the Weddell Sea.

At least 5,000 years old, the ice shelves collapsed in two stages over the last dozen years. One crumbled 12 years ago and the other followed in 2002.

Global warming is seen as the culprit behind the ice shelves' demise, said Gauthier Chapelle of the Polar Foundation in Brussels.

"These kind of collapses are expected to happen more," he said. "What we're observing here is probably going to happen elsewhere around Antarctica."

Melting ice shelves are not expected to directly contribute much to global sea level rise, but glaciologists believe these vast swaths of ice act like dams to slow down glaciers as they move over the Antarctic land mass toward the coast. Without the ice shelves, glaciers may move over the water more quickly, and this would substantially add to rising seas.

Since 1974, 5,213 square miles of ice shelves have disintegrated in the Antarctic Peninsula.

But the collapse of the ice shelves gave the scientists a unique opportunity to see what had been hidden beneath them; before the collapse, researchers could only peer through holes drilled deep into the ice.

Chapelle and other scientists from 14 nations traveled to the area aboard the icebreaking vessel Polarstern in a 10-week voyage to investigate underwater wildlife along the Antarctic peninsula, the part of the southern continent that curves up toward South America.

Looking down 2,800 feet into the icy water -- a comparatively shallow depth -- they found fauna usually associated with seabeds about three times that deep, in places where the creatures must adapt to scarcity to survive.

There were blue ice fish, with dorsal fins like ribbed fans and blood that lacks red cells, an adaptation that makes the blood more fluid and easier to pump through the animal's body, conserving energy at low temperatures.

Long-limbed sea stars, some with more than the usual five appendages, mingled with the ice fish, and groups of sea cucumbers were observed moving together, all in one direction.

The explorers also found thick settlements of fast-growing animals called sea squirts, which look like gelatinous bags, which apparently started colonizing the area only after the ice shelves collapsed.

Among the hundreds of specimens collected, the scientists identified 15 possible new species of shrimp-like amphipods, and four possible new species of cnidarians, organisms related to coral, jellyfish and sea anemones, the scientists said in a statement.

These specimens will be analyzed to determine whether they in fact are newly discovered species.