Brittlestars give clues to seamount life
Millions of starfish-like creatures have been found in a novel colony on a subsea mountaintop south of New Zealand, aiding knowledge of mysterious seamounts that dot the oceans, scientists said. Fewer than 200 seamounts -- mountains that rise from the ocean floor without piercing the surface -- have been surveyed out of an estimated 100,000 around the world. They are often rich in marine life in seas under threat from over-fishing. Tens of millions of tiny brittlestars were found on a peak 90 meters below the sea surface on the subsea Macquarie Range stretching 1,400 km (870 miles) south of New Zealand towards Antarctica, scientists from New Zealand and Australia said.They dubbed the peak, filmed with a robot submarine in April, "Brittlestar City" after the five-armed creatures that are a type of echinoderm related to starfish, sea cucumbers, sea lilies, and sea urchins.
Usually, corals and sponges are found on the peaks of seamounts, he told Reuters. In some places hundreds of the tiny brittlestars were crammed in per square meter on the flat top of the mountain, covering about 100 sq. kms. (38.61 sq. mile). The seamount rises 750 meters from the surrounding sea floor and is swept by a current about 4 km (2.5 miles) per hour that May help keep some predators away from the brittlestars, more often found on the flanks of seamounts. Brittlestars feed on plankton by simply waving their arms into the current. Food gets trapped on sticky mucus on their spiny arms. Knowledge of the state of life on seamounts in the Macquarie Range May also help monitor future changes, for instance if ocean currents around Antarctica are affected by global warming.
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