May 20, 2008

Swarms of Starfish Discovered Near Underwater Volcanoes

While studying eight Macquarie Ridge sea mountains scientists have discovered millions of starfish capturing food.

The team of 19 marine scientists spotted the phenomenon while studying the region, which spans 875 miles from south of New Zealand toward Antarctica and is home to several underwater volcanoes.

They had expected to discover the affects of global climate change while investigating the Antarctic Circumpolar Current, but the focus of the expedition became the underwater cameras' revelation of a large group of cardinal fish and huge coral.

"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 Dr. Mireille Consalvey.

"It challenged what we as scientists thought we knew."

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

Team leader Ashley Rowden said starfish usually only cover the slopes away from the top of the undersea mountains.

"It got us excited as soon as we saw it," Rowden said.

Researchers set out to study the site, named "Brittle Star City," on March 26 and returned to port in New Zealand's capital Wellington on April 26.

The collection of brittle stars, or ophiuroid ophiacantha, is "like a relic of ancient times," says biologist Tim O'Hara, a brittle star specialist who did not take part in the expedition.

"Normally fish would prey on them and eat them ... so for whatever reason there's a lack of fish predation there and it's seen this particular animal flourish," he said.

O'Hara, said the speed of the sea current in the area may partly explain why fish were not feeding on the tiny animals.

Australian oceanographer Steve Rintoul said there have been few measurements of the Antarctic Circumpolar Current, which "strongly influences regional and global climate" by carrying vast amounts of water and heat across oceans.

Fewer than 200 of the world's estimated 100,000 sea mounts that rise more than a half a mile above the sea floor have been studied in any detail.


Image Courtesy Wikipedia


On the Net:

Antarctic Circumpolar Current - Wikipedia