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Deep Sea Expedition Seeks to Unlock Coral Secrets

Posted on: Tuesday, 13 July 2004, 06:00 CDT

By MARGARET LILLARD

ABOARD THE RV SEWARD JOHNSON (AP) -- Steve Ross plucks a slender munida crab from a bucket of chilly water, then places it gently on a small branch of lophelia coral.

The bright red creature does what comes naturally in its usual habitat a thousand feet below the ocean's surface, obligingly extending its claws as if to catch any stray fish that might happen by.

"He would normally sit just like that in the water," Ross says, extending his own arm. As a blobby anglerfish sulks in another bucket, Ross smiles: "He was a lot easier to train than the fish."

Here in the wet lab of the research ship Seward Johnson, Ross and other scientists are busy sorting, cataloguing, testing and observing a sampling of the life found deep underwater that morning during a dive by the ship's deep-water submersible.

Ross, a member of the University of North Carolina at Wilmington research faculty, was chief investigator on the two-week expedition in mid-June to study deep water coral colonies on the East Coast, from Florida to North Carolina.

The group included 17 scientists and educators from the U.S. Geological Survey, the National Marine Fisheries Service and the North Carolina Museum of Natural Sciences. The ship and submersible, with five submersible crew members and 11 ship's crew, were supplied by the Harbor Branch Oceanographic Institution in Fort Pierce, Fla.

The samples, photographs and videos the group collected will help them establish baseline data about life in the deepest parts of the ocean, and how it interacts with plants and animals through the "water column" from the seabed to the surface.

The coral colonies are already known as great fishing spots for snapper and grouper, but there's little known about the interaction of species from the depths to the surface, or how they relate to ocean habitats around the world.

Deep sea exploration is becoming an increasing priority worldwide; the June edition of National Geographic magazine features similar research being done in the Monterey Canyon off the coast of California, and Harbor Branch will send another group of scientists to the Gulf of Mexico this summer.

For many years, the deepest part of the ocean was assumed to be barren - the cold, dark surroundings and immense water pressure inhospitable to life. Early attempts to study the area involved pulling up samples with nets and gave intriguing hints at what might be below.

The advent of submersibles, manned and unmanned, has allowed scientists to see the entire picture of life in deep water, and it's been surprisingly active and eye-catching when lit.

Many deep water invertebrates are bright red, a color that translates to black in the twilight below, said Kenneth Sulak, the team's co-principal investigator and a research fish biologist with the USGS from Gainesville, Fla.

Other animals are gray, white or patterned to camouflage themselves among the corals. "'It's a Twilight Zone kind of pattern," Sulak said.

The coral beds themselves can be immense, as much as two to three meters high and wide enough to fill a room.

The growing appreciation of the diversity of deep-sea life and how it interacts with the rest of the ocean's inhabitants is critical to understanding how deep-water fishing, oil exploration, and the laying of fuel pipelines and communication cable are affecting these remote reaches.

"We're moving into progressively deeper and deeper sea operations in the world," Sulak said.

The data can also have a practical benefit if scientists discover plants or animals that can be used in food, medicine or other forms to help humans. There's also the potential that the slow-growing deep water corals can hold historical climate data, as do the rings of trees.

"We're trying to determine what role these systems play in overall ocean productivity. And that, of course, is a direct payoff potentially if you're talking about fisheries and other activities that take place in deep water," Ross said.

"But we should be interested in these habitats anyway, even if there's not going to be a direct monetary benefit, because we can't predict what the benefits of biodiversity are."

Image credit: NSF

Image credit: NSF

Image credit: NSF

Ross and Sulak have been involved in collecting deep-sea data since the early 1990s, with this series of research on trophodynamics - or, in Ross's words, "who eats who" - beginning in 1999.

On past expeditions, they've located a shipwreck, noted wider ranges of some known animal species, discovered unknown varieties of familiar fish, and made initial maps and studies of the deep water coral banks. Each subsequent visit has allowed them to study changes in the habitat over time.

The expedition's most eye-catching piece of gear is its four-person submersible, an H.G. Wellsian collection of working parts and scientific gear built at Harbor Branch. Its largest feature is a bubble of clear material thick enough to withstand water pressure at depths of up to 3,000 feet.

Two people ride in it, one piloting and the other manipulating the sub's robotic arm and suction tube to pluck samples and place them in an assembly line of buckets. A backup pilot and another scientist ride in a smaller compartment in the back to collect more data.

Each dive is photographed and videotaped - more than 56 hours of video were shot during 24 dives on this year's trip.

"This is 3 1/2 hours of very intense activity. It costs of lot of money so we try to maximize our time each time we go down," Ross said. "We're seeing some of these animals in their habitat for the first time, so the video helps us see how they interact."

Other material is retrieved closer to the surface with nets, while instruments collect data on the sample area's temperature, current and salinity.

While the ship has on-board wet and dry labs, most of the work and study on what is collected occurs on shore in the months and years after the trip.

Ross notes that deep water corals grow slowly due to the lack of light, making mapping and preservation essential.

"Some of these deep water corals are hundreds of years old. Once they're damaged, these habitats don't recover, or they don't recover very quickly," he said.

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On the Net:

Life on the Edge 2004 expedition

NASA

More science, space, and technology from RedNova

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