Baffling giants in the ocean depths

Scientists investigating the icy waters of Antarctica said on Tuesday they had collected mysterious creatures including giant sea spiders and huge worms in the murky depths.Australian experts taking part in an international programme to take a census of marine life in the ocean at the far south of the world collected specimens from up to 2,000 m beneath the surface, and said many may of them have never been seen before. Some of the animals far under the sea grow to unusually large sizes, a phenomenon called gigantism that scientists still do not fully understand. "Gigantism is very common in Antarctic waters," Martin Riddle, the Australian Antarctic Division scientist who led the expedition, said in a statement. "We have collected huge worms, giant crustaceans and sea spiders the size of dinner plates." The specimens were being sent to universities and museums around the world for identification, tissue sampling and DNA studies. The expedition is part of an international effort to map life forms in the Antarctic Ocean, also known as the Southern Ocean, and to study the impact of forces such as climate change on the undersea environment. Three ships — Aurora Australis from Australia, France's L'Astrolabe and Japan's Umitaka Maru — returned recently from two months in the region as part of the Collaborative East Antarctic Marine Census. The work is part of a larger project to map the biodiversity of the world's oceans.

French and Japanese ships sought specimens from the mid- and upper-level environment. The Australian ship plumbed deeper waters with remote-controlled cameras. "In some places every inch of the sea floor is covered in life," Mr. Riddle said. "In other places we can see deep scars and gouges where icebergs scour the sea floor as they pass by." Among the bizarre-looking creatures spotted were tunicates, plankton-eating animals that resemble slender glass structures up to a metre tall "standing in fields like poppies," Mr. Riddle said. Others were equally baffling. "They had fins in various places, they had funny dangly bits around their mouths," said Mr. Riddle. "They were all bottom dwellers so they were all evolved in different ways to live down on the sea bed in the dark.

The Hindu, February 20, 2008