What's going on down there? 2,000 ocean scientists do the biggest, wettest census ever

Science News,  Feb 17, 2007  by Susan Milius

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Researchers have taken clam digging to new extremes. To look for any mollusks or other creatures that live under several hundred meters of ice, scientists have just finished searching the ocean bottom off the Antarctic Peninsula. They cruised waters made more accessible when the Larsen A and B Ice Shelves shattered. For the exploration, they used a German icebreaker that pushes along at 5 knots through ice 1.5 m thick.

An earlier expedition to the area had videoed what looked like dams living there. That earlier expedition couldn't bring back samples, but the new cruise could. The team is scheduled to announce its findings--of any mollusks and other forms of life--this week. The team has hinted at success though; the weekly reports that it posted on the Internet include pictures of clamshells.

The Polarstern expedition to Antarctica is part of a 10-year, international project called the Census of Marine Life. It started in 2000 with the mission to survey the biodiversity of the oceans. Some 2,000 researchers at schools, museums, and government agencies in more than 70 countries are developing new methods for studying marine life and are sampling the residents of both familiar and unfamiliar waters. All the projects address some aspect of three basic questions: What used to live in the sea? What lives there now? What will be there in the future?

Some general trends are already emerging, such as worrisome drops in some ocean species' populations as modeled by computer programs. Yet the current phase of the census emphasizes fieldwork over computer modeling, says Ron D'Or, the census' scientific coordinator. The Polarstern icebreaker cruise was the 20th sponsored by the census last year.

With all that searching of the seas, scientists have met some unexpected new underwater neighbors.

FRUSTRATED The marine census grew out of frustration, says D'Or, a marine biologist at Dalhousie University in Halifax, Nova Scotia. A 1995 report from the National Research Council in Washington, D.C., to several federal agencies warned that human activity is dramatically changing populations of sea creatures. To blunt such insults, the report concluded, marine biologists need to do much more research on the dynamics of marine biodiversity. Despite this call to action, no new government funding materialized.

So, Frederick Grassle, one of the drafters of the report, started talking to the New York City-based Alfred P. Sloan Foundation about private funding. The foundation agreed to put up money for marine biologists to get together, write grant proposals, and start ambitious ventures that might otherwise have remained day dreams.

"There were perfectly good reasons why people didn't know very much about the ocean," says D'Or. For example, standard winches on research vessels can take 8 hours just to lower a collecting contraption to the bottom, and then another 8 hours to haul a single sample back up. Because cruise time runs up big tabs in a hurry--the Polarstern costs about $77 a minute--deep-ocean samples are intellectual luxury goods. And only recently did remotely operated vehicles and underwater digital cameras become adept at collecting deep-ocean samples and images.

Originally, the planners discussed a "census of fishes," says D'Or. But the scope of work gradually expanded. D'Or specializes in squid and got involved in the project at a meeting unpoetically titled "Nonfish Nekton," or animals that aren't fish but can still swim better than plankton.

D'Or reports that the original census organizers "let us nonfish-nekton people in, and the plankton people, and the microbial people, and [then] everybody said, 'That's dumb--you can't just have a census of fishes. You have to have a census of marine life'"

Now, the census has grown to 17 projects. One searches for historical records of sea life, such as fishing communities' tax records or church tithings, as measured in barrels of their catch. Another relies heavily on modeling to predict the future of marine populations. Fourteen projects focus on field studies of marine creatures--from albatrosses soaring over the water to microbes dwelling several kilometers deep.

The remaining census participants are creating the Ocean Bio-geographic Information System (OBIS), which offers Internet access to 12.9 million records of 77,000 species from 200 databases.

Planners early on recognized that abyssal depths need special attention. Scientists' knowledge of marine life is, literally, shallow. Although the ocean bottom lies 4,000 m underwater on average and in places plunges much deeper, nearly 90 percent of the original entries into OBIS came from the top 100 m of water, and 99 percent came from the top 3,000 m. Nobody knows how many or what types of organisms live at lower depths, D'Or says.

RED FISH, BLUE FISH With a wide variety of techniques, scientists are working to take a good look into the sea. Nicholas Makris and his fish-tracking research group at the Massachusetts Institute of Technology recently unveiled a sensor that can observe 10,000 square kilometers at a time over the continental shelf.