Scientists investigating the icy waters of Antarctica said Tuesday they have collected several mysterious creatures from 2,000 metres below the ocean's surface, including giant sea spiders and huge worms.

Australian experts taking part in an international program to conduct a census of marine life in the ocean at the far south of the world said many species may never have been seen before.

Tunicates, animals that resemble glass tulips, were photographed in Antarctic waters by Australian scientists taking part in a census of marine life in January 2008.
(Martin Riddle, Australian Antarctic division/Associated Press)

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 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.

Strange fins, dangly bits and huge eyes

"Not all of the creatures that we found could be identified and it is very likely that some new species will be recorded as a result of these voyages," said Graham Hosie, head of the census project.

"In some places every inch of the sea floor is covered in life," 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 the scientists spotted were tunicates, plankton-eating animals that resemble slender glass structures up to a metre tall "standing in fields like poppies," Riddle said.

Other animals were equally baffling. "They had fins in various places, they had funny dangly bits around their mouths," Riddle said.

"They were all bottom-dwellers so they were all evolved in different ways to live down on the seabed in the dark. So many of them had very large eyes — very strange looking fish."

Study measures impact of climate change

The expedition is part of an ambitious 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.

The French and Japanese ships sought specimens from the mid- and upper-level environment, while the Australian ship plumbed deeper waters with remote-controlled cameras.

Scientists are planning a follow-up expedition in 10 to 15 years to examine the effects of climate changes on the region's environment.