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But the data remained unpublished until Marianne Moore of Wellesley College visited the lake with a class and heard about lake measurements stretching back 60 years.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."
The team also found that phytoplankton had increased by about threefold, and they tracked a similar tripling of one type of zooplankton in the lake.
Plankton form the base of the food web in the lake, so changes to these populations may affect organisms higher up the food chain, many of which are endemic only to Lake Baikal.
The lake's 25-million-year history has made it the most biologically diverse lake on the planet, Hampton said, with more than half of animals and 30 percent of plants not found anywhere else.
"Something like 40 percent of the species in Baikal may not have been described yet," Hampton added.
The lake hosts the world's only freshwater seal, the Baikal seal, which rears its pups in ice caves on the frozen lake. Sponge forests -- rare for lakes -- grow beneath the surface.
"It's like a freshwater Galapagos," Hampton said.
"Even an enormous lake like Baikal looks like it is being affected by climate change," said John Smol of Queen's University in Kingston, Ontario, who was not a part of the study. "It just shows you how pervasive climate change is going to be."
"It's a human story of incredible dedication," Smol added. "It was a family of three generations that had the vision and understanding to see that this is worth doing. A fundamental lesson here is the power of long-term monitoring data. You get very little credit for it."
Kozhov certainly would not have foreseen what it would be used for in 2008. "No one was even thinking climate change in the 1940s," Smol said. "But you can mine the data after the fact."
Related Links:
Jessica Marshall's Blog: EnvironMental Case
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