Undersea Mountain Photos: Brittlestar Swarm, More Found

Brittlestar Swarm

Photograph courtesy NIWA

Brittlestars swarm on a seamount in an undated picture taken at Macquarie Ridge, an underwater mountain south of New Zealand in 2008.

With mucus-covered feathery spines on their arms, the invertebrates capture microscopic plants and animals from the passing current, scientists say.

(See "'Brittle Star City' Found on Antarctic Seamount.")

CenSeam brought together more than 500 scientists, policy makers, and conservationists from around the world to study the types of marine life that make their homes on seamounts and how the creatures are affected by human activity.

With CenSeam, seamount researchers finally have a way to pool their results and coordinate their projects, noted Karen Stocks, a CenSeam scientist at the University of California, San Diego.

"Historically, seamount research hasn't been coordinated at all," she said. "There would be an expedition, they would go to an individual seamount or seamount chain, and publish their results."

Published October 1, 2010

Feeding Starfish

Photograph courtesy NIWA

A bright orange brisingid starfish on a seamount in the Macquarie Ridge near New Zealand raises its arms to feed in 2008.

Like underwater cities, seamounts sometimes are home to much higher populations of marine life than the surrounding seafloor, CenSeam scientists have found.

The rocky surfaces on many seamounts offer a hard substrate for corals to attach to. Once a sizable coral population has been established, other creatures—such as sponges, sea anemones, starfish, and fish—can move in.

(More Census of Marine Life pictures: "Hard-to-See Sea Creatures Revealed.")

"These corals create a habitat that wouldn't be there otherwise," CenSeam's Consalvey said.

Published October 1, 2010

Spawning School

Photograph courtesy NIWA

In 2008, a dense school of orange roughy fish gather above a seamount in New Zealand's Chatham Rise to spawn.

Fishers who harvest orange roughy have traditionally gathered at seamounts during spawning season to catch large numbers of the fish at once. (Related: "Weird Creatures Found on Deep-Sea 'Mountain Range.'")

But such seamount communities are very disturbed by fishing and are slow to recover, CenSeam researchers have demonstrated for the first time.

"It was pretty obvious that bottom-trawling was going to have a substantial impact on seamount communities, but it hadn't been scientifically proven," CenSeam's Stock said.

For example, in one study, CenSeam scientists compared photographs of seamounts that had been trawled by commercial fishing with those of unfished seamounts.

They found that about 20 percent of the unfished seamounts were covered by coral, while fished seamounts had less than one percent of coral coverage.

Published October 1, 2010

Biodiversity Refuge

Photograph courtesy NIWA

A crowded assemblage of deep-sea sponges and corals—including a large orange primnoid sea fan—are seen on the Macquarie Ridge seamount in 2008.

CenSeam researchers have determined that seamounts might serve as sanctuaries for marine life during periods of extreme environmental events, such as climate change-induced ocean acidification.

"In the future, seamounts might act as repositories of biodiversity," CenSeam's Consalvey said.

"They're undersea mountains that stick up from a flatter terrain, so they offer a variety of different depths. So if you've got a change of conditions, animals can find refuge up or down their slopes."

(See related pictures: "Vast New Ocean Refuge Home to Huge Crab, Coral.")

Published October 1, 2010