US scientists delve into research by diving into Lake Superior
Chicago — An upward trek to the moon -- or even a mountaintop -- it's not. The direction is down. And the surroundings are wet. But the scientists who will be diving daily to the bottom of Lake Superior during the next month should experience some of the same adventure of discovery.
And they hope that what they learn will help advance research in their various fields.
Making the series of dives in a 22-foot minisubmarine are biologists, zoologists, chemists, and geologists from several universities. Under a project coordinated by Michigan State University (MSU), they expect to probe everything from the chemical content of lake-bottom sediment to the question of whether lake trout are again being endangered by the eel-like lamprey.
The National Oceanographic and Atmospheric Administration (NOAA) is supplying sophisticated equipment and $500,000 in funding.
``This is really the first time we've gone into the Great Lakes -- and I'm sure it won't be the only time,'' says Elliott Finkle, the director of NOAA's National Undersea Research Program (NURP). To date, the program has focused on ocean research.
Mr. Finkle says that to make the shift from salt water to the less-dense fresh water, the four-man sub had to be wrapped in blocks of gray foam to add buoyancy.
Lake Superior was apparently selected for the first expedition because it is the purest and deepest of the Great Lakes. ``Observing the natural process of pollutants and chemicals [in such clean water] offers a better base for understanding,'' says MSU spokesman Charles Downs.
The current venture marks the first time Superior has been probed to such depths. Most human divers have gone no deeper than 300 feet. At one point, the sub will descend 1,330 feet below the surface, the deepest point in the Great Lakes.
Scientists will travel along the lake's surface aboard the 176-foot Seward Johnson, a NOAA research vessel.
The minisub vehicle is equipped with a manipulator arm to collect samples and with a so-called ``critter getter'' to hold biological specimens. Two video cameras can record every move.
NOAA's Finkle says the TV tapes can be played on the research ship. If the scientists find something is missing, they can easily return to the precise spot where the cameras were shooting.
The experiments were picked as a package over 41 other proposals to the NURP. The emphasis was on tests that could be done only underwater.
``There are plenty of problems in the lakes. Some we can solve working from the surface, and some we can't,'' Finkle notes.
One of the earliest dives, made this week, looked at the effects of nylon gill nets lost by fishermen, which continue to trap and kill fish after falling to the lake bottom.
The explorers will also examine a deep, rock canyon that is a major spawning place for lake trout. The fish have been making a comeback after stocks were almost depleted in the 1960s by overfishing and lampreys.
Scientists have had marked success in destroying lamprey larvae with chemicals. But there have been reports of the development of a new genetic strain of deep-water lamprey, which is less easily controlled by chemicals. Lake-bottom larvae samples will be taken.
Columbia University geologist Roger D. Flood is eagerly awaiting his minisub trip Aug. 3. He and his colleagues will examine the composition, shape, and movement of sediment furrows on the bottom of Lake Superior. The furrows form parallel depressions, like tire grooves, that can be as many as three feet deep. ``It will be the biggest single dive program,'' he says.
The last leg of the trip is intended to help cultural historians by attempting to document at least a few of the 350 shipwrecks believed to have occurred in Superior over the last 130 years.