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The Oddities of Lake Baikal

Some Alaska researchers are especially pleased at the current thaw in the Cold War. They're happy about the improved chances to work on one of the most extraordinary bodies of water in the world: Siberia's Lake Baikal.

It may be hard on northern North American egos, but next to Baikal, our mighty lakes seem to shrink. Iliamna, Kluane, even Great Slave are youthful ponds in comparison to this elder giant. Baikal's surface area, about 34,000 square kilometers (more than 13,000 square miles), ranks seventh among the world's lakes, covering about the same area as the country of Belgium. But at 1637 meters (nearly 5400 feet), it is the deepest lake on the planet. The combination of area and depth means that Lake Baikal holds more fresh water than all five Great Lakes combined.

Lake Baikal lies in a rift valley--a place where the earth's crust is pulling apart. The section of Asia lying northwest of the lake is pulling away from the part to the southeast at the rate of two centimeters (about three-quarters of an inch) a year. That helps explain its great depth, and also its great age. Much scientific interest stems from Baikal's age. Nearly all big freshwater bodies are geologically young, less than 20,000 years old (Iliamna, for example, only appeared after the glaciers left that part of Alaska). Lake Baikal is at least a thousand times older, and the highend estimates go to 50 million years.

That great age offers time for an enormous layer of sediment to build up on the lake bed. In places, it lies five kilometers thick. To most people, that might sound simply like a lot of mud. To scientists, it offers a record of tens of millions of years, recorded in layers never disturbed by glaciation. Fossils trapped in the sediment could provide a history of the ecosystems in and around the lake. Organically produced carbonate, found in mollusc and shrimp shells, contains a ratio of stable isotopes of oxygen that varies according to the temperature of the water in which the organism grew. If they can find enough carbonate, the scientists will gain a picture of changes in the climate of northern Asia.

Baikal's antiquity also offers unusual possibilities for researchers in the life sciences. The lake holds 1550 species or variants of animals and 1085 of plants; of these, 1000 occur nowhere else. Organisms have adapted and evolved to fit the numerous niches in this freshwater sea, to the point a British scientist has described as an "evolutionary explosion." Some of these creatures look familiar, Lake Baikal has grayling very like those found in Alaska--only much bigger. Others are exotic by anyone's standards: one of the 80 species of flatworms in the lake is the world's largest (40 centimeters or nearly 16 inches long). It eats fish.

Fish are also the diet of choice for the Baikal seal, the animal that already has drawn some Alaskans to Siberia. John Burns of the Department of Fish and Game, and Bob Elsner and Bud Fay of the University of Alaska Fairbanks are the ones I know, but there are probably others. Baikal seals are irresistibly interesting for many marine mammalogists--in part because they aren't marine.

Populations of seals do occur elsewhere in lakes, even in our own Iliamna. Lake Baikal's seals, however, have been there for a few million years. Probably they journeyed down the Angara River, the one outlet of the lake, from the Arctic Ocean. They've had time to evolve away from other members of the hair seal family and develop special features. According to Fay, they look like ordinary, rather dark seals, except their forelimbs differ quite a bit from those of their seagoing cousins. Baikal seals have bigger, stronger claws and unusual forelimb musculature. Those features would be useful for scraping air holes in freshwater ice, which is denser and stronger than sea ice.

Baikal seals also have unusually wrinkled faces. It's tempting but wholly unscientific to speculate they developed that feature recently, from wrinkling up their noses at the increasing pollution in the lake. The Soviet Union is working on that problem, which--at least before Chernobyl--was the most emotion-rousing environmental concern in the country.

Finally, for Alaskan scientists accustomed to working in splendid scenery, Lake Baikal seems downright homey. Forest and mountains surround the lake; it has the complicated, eye-pleasing configuration of a drowned fiord. Tourists, though, might wait a bit before visiting. The gulags are gone, but the first-class hotels haven't yet arrived on the shores of beautiful Lake Baikal.