Lake Baikal Warming ID'd by One Family's Tradition

June 6, 2008 -- The devotion of three generations of a scientific Siberian family has documented warming and ecological changes in Lake Baikal -- the world's deepest, oldest and most voluminous lake.

Beginning in 1945, Mikhail Kozhov, a professor at Irkutsk State University in Irkutsk, Russia, drew samples from the lake, 1.5 miles offshore, down to 800 feet, about every seven to 10 days year-round. Later, his daughter took over the sampling, and her daughter, Lyubov Imest'eva, also at Irkutsk State University, continues to this day.

But the data remained unpublished until Marianne Moore of Wellesley College visited the lake with a class and heard about lake measurements stretching back 60 years.

At first she thought she had misunderstood, but eventually she, and colleague Stephanie Hampton of the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara, began collaborating with Imest'eva to analyze the data and make the findings public. They were published recently in Global Change Biology.

Among the team's findings is that the lake, which holds 20 percent of the world's liquid freshwater, has warmed by more than 2 degrees Fahrenheit since 1946, a rate three times faster than the global average air temperature rise.

"I was surprised by that, frankly, and I know that lakes worldwide are warming," Hampton said. Lake Baikal is so vast, and the water mixes completely from top to bottom, so Hampton and others expected it would resist warming compared with smaller bodies of water.

"It's probably related to ice cover," Hampton said. Lake Baikal is typically topped by ice from about January to May. Over the past century, the number of days of ice cover has decreased by 14 to 19 days. "That's a smaller part of the year that the lake is insulated from the air and the sun."