May 6, 2008
Family Science Project Yields Surprising Data About a Siberian Lake
By CORNELIA DEAN
In 1945, when Stalin ruled the Soviet Union, Mikhail M. Kozhov began keeping track of what was happening under the surface of Lake Baikal, the ancient Siberian lake that is the deepest and largest body of fresh water on earth.
Every week to 10 days, by boat in summer and over the ice in winter, he crossed the lake to a spot about a mile and a half from Bolshie Koty, a small village in the piney woods on Baikal’s northwest shore. There, Dr. Kozhov, a professor at Irkutsk State University, would record water temperature and clarity and track the plant and animal plankton species as deep as 2,400 feet.
Soon his daughter Olga M. Kozhova began assisting him and, eventually her daughter, Lyubov Izmesteva, joined the project. They kept at it over the years, producing an extraordinary record of the lake and its health.
Now Dr. Izmesteva and scientists in the United States have analyzed the data and concluded, to their surprise, that the water in Lake Baikal is rapidly warming. As a result, its highly unusual food web is reorganizing, as warmer water species of plankton become more prevalent. These shifts at the bottom of the food web could have important implications for all of the creatures that live in the lake, they say.
Although Dr. Kozhov is famous among scientists who study lakes — his 1961 book “Lake Baikal and Its Life” is considered a classic — the new report is “the international debut of the Kozhov family’s legacy of research,” Stephanie E. Hampton of the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara, said in an e-mail message.
She led the work along with Dr. Izmesteva who, like her mother and grandfather before her, is a professor at the university and a researcher at the biological field station it established in Bolshie Koty in 1918. Their findings are being reported this month in the journal Global Change Biology.
Like others who have seen the data, Dr. Hampton said in an interview that she was in awe of the people who had collected it. “Even in the spring, summer and fall, this is tough,” she said. “In the winter to go out a mile and a half on the ice and break through it to take water samples, in a year-round effort for 60 years, is pretty amazing to me. Every time I think about it I am humbled.”
Marianne V. Moore, an ecologist at Wellesley College and another researcher on the project, said she learned about the data in 2001 when she took students in her class, “Baikal and the Soul of Siberia,” to the lake. Dr. Izmesteva spoke to the group and showed a few slides, which the translator said had been drawn from a 60-year record. “I thought he had made a mistake,” Dr. Moore recalled. “So I basically ignored it.”
When she returned with another class two years later and another scientist mentioned the data, “my jaw dropped to the floor,” she said. “I realized this is just extraordinary.”
She got in touch with Dr. Hamilton, who is an expert in the analysis of complex ecological field data, particularly the use of statistical techniques to discern real trends in the messy ups and downs of nature. The center in Santa Barbara financed the collaboration.
Baikal is a place of unusual biodiversity, with many species found nowhere else. Among them are giant shrimp, bright green sponges that grow in shallow water forests and the Baikal seal, the world’s only exclusively freshwater seal. In 1996, the United Nations Educational, Scientific and Cultural Organization, or Unesco, designated the lake a World Heritage Site.
Although it is known that warming is more intense at high latitudes, as in the Baikal area, and that water is warming in other major lakes, including Lake Tahoe in Nevada and Lake Tanganyika in central Africa, many scientists had thought that Lake Baikal’s enormous volume and unusual water circulation patterns would buffer the effects of global warming.
Instead, the researchers report, surface waters in Lake Baikal are warming quickly, on average by about 0.4 degrees Fahrenheit every decade. At a depth of about 75 feet, the increase is about 0.2 degrees per decade, they say, enough to jeopardize species “unable to adapt evolutionarily or behaviorally.”
Over the last 137 years, the researchers say, the ice-free season has lengthened by more than two weeks, primarily because ice forms later in the year. The database, including data on chlorophyll that the family started collecting in 1979, suggest that the “growing season” for plankton and algae has lengthened in the lake. Chlorophyll levels have tripled since measurement began, the researchers said.
Ordinarily, the researchers said in their report, this increased plant growth would be accompanied by decreases in water clarity, but that is not what the data show at Lake Baikal. This finding, they said, “highlights the importance of establishing monitoring for ‘early warming’ before a need for monitoring may be perceived visually.”
Now, Dr. Hampton said, she and other researchers are examining how the Kozhov family’s data fit with records of ecological phenomena elsewhere. So far, she said, “the data correlate well.”
“You could not make up something like this.” she added.
Dr. Moore said Dr. Kozhov died in 1968 and his daughter Olga died in 2000. The family persisted in their work through years of political, economic and social turmoil, especially the collapse of the Soviet Union after the fall of the Berlin Wall in 1989 when, Dr. Moore said, “funds for the program just dried up.”
Today, she said, Dr. Izmesteva and her colleagues pay for their work in part with fees they earn by consulting or doing environmental impact assessments.
“They sustain the program any way they can,” Dr. Moore said.
Source: http://www.nytimes.com/2008/05/06/science/earth/06lake.html
