At One Undersea Volcano, Star Heaven

May 19, 2008 -- Marine scientists surveying a large undersea mountain chain were amazed to find millions of tiny brittle stars swirling their arms to capture food in the undersea current.

An expedition by 19 scientists studied the geology and biology of eight Macquarie Ridge sea mounts. They are part of a string of underwater volcanoes -- dormant for millions of years -- that stretches 875 miles from south of New Zealand toward Antarctica.

The scientists also investigated the world's biggest ocean current -- the Antarctic Circumpolar Current -- amid expectations they would find evidence of climate change in the Southern Ocean.

While the expedition's cameras found a wide range of corals and a high density of cardinal fish, the vast collection of brittle stars was the highlight of the voyage.

"I've personally never seen anything like this -- all these animals, the sheer volume -- all waiting for food from the current," expedition member and marine biologist Mireille Consalvey said Monday. "It challenged what we as scientists thought we knew."

Expedition leader and marine biologist Ashley Rowden said brittle stars usually cover only slopes away from the top of the undersea mountains.

"It got us excited as soon as we saw it," Rowden said of the site, dubbed "Brittle Star City."

The animals are about 0.4 inch across, with arms about 2 inches long.

The expedition began March 26 and returned to port in New Zealand's capital Wellington on April 26.