Exotic animals - in Antarctica
2007-02-27 12:24
Washington - 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 have reported..
This is the first time explorers have been able to catalogue
wildlife where two mammoth ice shelves used to extend for some
10 000 square kilometres 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, 13 500 square kilometres of ice
shelves have disintegrated in the Antarctic Peninsula.
Sea squirts
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 travelled 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 850m 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 colonising 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.