David Perlman, San Francisco Chronicle Science Editor
San Francisco Chronicle June 26, 2010 04:00 AM Copyright San Francisco Chronicle. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.Saturday, June 26, 2010
Thirty-five miles west of the Point Reyes Lighthouse, and 10,000 feet beneath the ocean surface, scientists steering a robot submersible have found beds of cold-water corals that provide a unique habitat for countless sea creatures, from brittle stars to octopus and rockfish.
"The fragile corals we found on the seabed are spectacular habitats for fish and many other organisms of all kinds that need protection," said Dan Howard, superintendent of the Cordell Bank National Marine Sanctuary.
Howard returned to land Friday with a scientific crew of 15 after six wave-pounded days and nights cruising on a research vessel over the sanctuary's outer margins. Of six coral species surveyed by the crew, two appear to be new to the region, and many are "gorgeous," he said.
The corals in the Cordell Bank sanctuary and the adjoining Gulf of the Farallones National Marine Sanctuary are unknown in the colorful reefs of the tropics; they live out of sight in the deeper, colder regions of the oceans. But like their warm-water counterparts, they need protection too, as bottom trawling by some commercial fishermen and the increasing acidity of the oceans threatens them, Howard said.
The scientists were aboard the National Oceanic and Atmospheric Administration's Research Vessel MacArthur II, which is being used to survey all five national marine sanctuaries on the Pacific Coast, from the Olympic Peninsula off Washington to the Channel Islands off Santa Barbara. The mission is to study the deep-water corals and the ocean's chemistry.
The researchers were aided by a crew from the University of Connecticut that controlled a remotely operated undersea vehicle named the Kraken II, which dived more than 1,700 feet to collect samples and photograph the corals along with the sponges, octopi, sea urchins and other organisms living among them.
The ROV's mission was delayed for two days by fierce 30-knot winds and 9-foot seas. Still, it made 100 observations. The robotic vehicle collected water samples from 4,000-feet deep to determine levels of nutrients, salinity, acids and carbons to create basic data for the region that will be compared with future levels at NOAA's Pacific Marine Environmental Laboratory in Seattle.
Among the corals that exist both at Cordell Bank and the Gulf of the Farallones sanctuaries are species of fan-shaped crinoids whose evolution dates to 450 million years ago and are among the oldest life forms known. The survey teams also observed coral species known as primnoids, Howard said.
One mystery emerged from the ROV's images: many of the boulders on the sea bottom were unaccountably rounded, as if they had been shaped by some giant hand, Howard said. It's possible that the rocks had been pounded over and over again by heavy surf about 12,000 years ago, when they lay on a shoreline of a Pacific ocean whose surface was far lower, said Guy Cochrane, a marine geologist from the U.S. Geological Survey in Menlo Park, who was aboard the MacArthur II to study the contours of the sanctuary's margin.
Immediately after the scientists came ashore Friday, the ship headed south toward Santa Barbara, where another group will survey more corals of many species known to inhabit the deep waters of the Channel Island National Marine Sanctuary.
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