The temperature of the world's largest freshwater lake in Siberia, has jumped up significantly thanks to global warming, scientists have said.
The team of Russian and American scientists, drew on 60 years of long-term studies of Russia's Lake Baikal.
In 1996, the United Nations Educational, Scientific and Cultural Organization (UNESCO) declared the lake a World Heritage site because of its biological diversity. It boasts 2500 plant and animal species, with most, including the freshwater seal, found nowhere else in the world.
The lake contains 20 percent of the world's freshwater, and it is large enough to hold all the water in the United States' Great Lakes. It is the world's deepest lake as well as its oldest; at 25 million years old, it predates the emergence of humans.
Now, in their research paper, the scientists have detailed the effects of climate change on Lake Baikal - from warming of its vast waters to reorganization of its microscopic food web.
"Warming of this isolated but enormous lake is a clear signal that climate change has affected even the most remote corners of our planet," said Stephanie Hampton, an ecologist and deputy director of the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara, California.
According to Henry Gholz, program director for NCEAS at the National Science Foundation (NSF), which funded the research, "The conclusions shown here for this enormous body of freshwater result from careful and repeated sampling over six decades."
The data on Lake Baikal reveal significant warming of surface waters and long-term changes in the food web of the world's largest, most ancient lake, according to the researchers.
"Increases in water temperature (1.21 degree C since 1946), chlorophyll a (300 percent since 1979), and an influential group of zooplankton grazers (335 percent since 1946) have important implications for nutrient cycling and food web dynamics," they added.
The scientists conclude that the lake now joins other large lakes, including Superior, Tanganyika and Tahoe, in showing warming trends.
"But, temperature changes in Lake Baikal are particularly significant as a signal of long-term regional warming," said the researchers. "This lake was expected to be among those most resistant to climate change, due to its tremendous volume and unique water circulation," they added.