Climate Change Affects Lake Baikal, Russia – August 20th, 200953.1N 107.6E
Siberia’s Lake Baikal, the world’s largest and most biologically diverse lake, faces the prospect of severe ecological disruption as a result of climate change, according to team of U.S. and Russian scientists, CNN reports.
Publishing their analysis in BioScience magazine the team found the most pressing threat came from the dependence of the lake’s food chain on microscopic algae. Lake Baikal’s algae are particularly vulnerable to expected reductions in the length of time the lake is frozen each winter. Here, the lake can be seen unfrozen during the summer months. For a winter image, please click here. The close-ups focus on the southern part of the lake and Irkutsk, Siberia’s largest city, Olkhon Island in the lake’s central section, and the Selenga River Delta on the eastern shores.
The report’s authors say Lake Baikal’s climate has become measurably milder over recent decades, and that annual precipitation is expected to increase. The average ice depth in the lake is believed to have decreased in recent decades, and the ice-free season to have increased. Changes in the lake’s food-chain composition have been noted, the scientists say.
Shorter periods of ice cover is expected to slow the growth of the lake’s algae, the authors say; the organisms bloom under the ice in springtime and are highly dependent on ice cover for their reproduction and growth.
Algae is the principal food of tiny crustaceans abundant in the lake, which in turn are food sources for the lake’s fish. The crustaceans could also be affected by changes in the transparency of the ice, an expected result of shifting precipitation and wind patterns.
Shortened periods of ice cover and changes in the ice’s transparency may also harm the Baikal seal, the lake’s top predator and the world’s only exclusively freshwater seal. Because the seals mate and give birth on the ice, premature melting forces them into the water before molting and drastically reduces their fertility, the authors say.
A warmer, wetter climate may be the principal threat to Lake Baikal’s unique biological heritage, but it is not the only one, say the report’s scientists. The secondary effects of climate change, including greater nutrient inputs and industrial pollution from melting permafrost, may also exact a toll on an already-stressed ecosystem.