Researchers studying Siberia's Lake Baikal have said they plan to use the lake to test the potential use of methane clathrates as an energy source, but that the lake itself would not be tapped for the fuel.

Methane clathrates, which look like ice and are found mainly in Antarctic ice cores and ocean beds, are composed of crystallized water molecules trapping methane and other gases. Baikal, the world's deepest lake, holds large volumes of clathrates in its sediment.

A member of the research team conducting a series of mini-submarine dives to lake's depths told RIA Novosti on Tuesday: "We are developing the scientific basis for creating production technology" for methane clathrates.

The experiment, to be jointly conducted with Japanese scientists, is scheduled for next year, Oleg Klystov, laboratories director at the Irkutsk-based Limnological Institute, said.

He stressed that the Baikal "natural laboratory" is being used purely for research, and that if such technology were developed it would only be employed at other sites.

Clathrates, also known as gas hydrates, hold vast reserves of potentially climate-warming methane, and are a major source of concern for environmentalists. Scientists have suggested that if global temperatures were to rise above a critical level, the gas could be rapidly released, dramatically altering the Earth's atmosphere.

The second stage of a major expedition to explore the depths of the lake began on August 20. During the ongoing expedition, the Mir-1 and Mir-2 mini-submarines have enabled scientists to take samples of oil that seeps through cracks in the lake's bedrock and is digested by the lake's organisms.

Baikal is the world's oldest lake, with an age estimated at 25 million years. Scientists taking part in the current expedition, during which 160 deepwater dives are planned over the next two years, have stressed that research is not aimed at exploiting possible oil and gas reserves, but at protecting Baikal's unique ecosystem.

The lake has been the focus of major environmental scares in recent years, with a last-minute change to an oil pipeline route that was set to pass near Baikal's shores, and environmental regulators' claims against a pulp mill accused of pumping large volumes of toxic waste into the lake.

A spokesman for the Baikal preservation foundation told RIA Novosti on Tuesday that during a mini-sub dive on August 31, scientists took water samples near the Baikal Pulp Mill at a depth of over 1,000 meters to assess the extent of the environmental damage caused by the mill's waste.

"The results of the research will be known in around two months, after a laboratory analysis of the samples," the spokesman said.

The Baikal Pulp Mill, built in the mid-1960s, is located on the lake's southern shore, and is the only facility still pumping waste into the lake. The mill is owned by Continental Management, a subsidiary of billionaire Oleg Deripaska's industrial conglomerate Basic Element.

The mill plans to switch to a closed water cycle by September 10, a few days ahead of a government-set deadline.

Baikal, a UNESCO World Heritage site, holds around 20% of the planet's freshwater.