Published online 28 July 2008 | Nature | doi:10.1038/news.2008.986

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Scientists to dive to the bottom of the world's deepest lake

Russian team explores the depths of Lake Baikal.

In an adventure worthy of Jules Verne, Russian scientists are preparing to dive to a depth of 1,637 metres — the very bottom of Siberia’s Lake Baikal.

MIRDown, down, deeper and down: the MIR submersible prepares for action.L. Murphy / NOAA

The team will make its first attempt at the record dive tomorrow, using the manned submersibles MIR 1 and MIR 2 — already famous for their performance in the movie Titanic.

The expedition has attracted huge media coverage in Russia and is led by Anatoly Sagalevich of the P. P. Shirshov Institute of Oceanology in Moscow. Also involved is well-known Russian explorer Artur Chilingarov, a member of the team that used MIR 1 to plant Russia’s flag on the seabed more than 4,200 metres below the North Pole in August 2007.

Over thirty dives, the scientists will take water and sediment samples from Lake Baikal, and hunt for hydrothermal vents that spew superheated water into the lake, says Robert Nigmatulin, head of the Shirshov Institute.

He adds that the team also aims to collect gas hydrate deposits at the bottom of the lake. At high pressure and low temperature, this ice-like rubble forms as methane gas is trapped in a crystalline lattice of water molecules.

No one has ever retrieved gas hydrates from the depths of the lake, although they have been found in boreholes drilled more than a hundred metres below the lake bed, and have also shown up in seismic surveys. Nigmatulin hopes that samples collected by the submersibles could reveal more about the conditions needed for the hydrates to form, as they have been proposed as a potential energy source.

Baikal mapLake Baikal is in Siberia, close to Russia's border with Mongolia.

The submersibles are used to reaching depths of 6,000 metres, but they are designed for use in salt water. The different density of freshwater means that they have already spent a week doing test dives down to 400 metres to ensure that deeper dives can be safely controlled.

Lake Baikal is not only the deepest lake in the world — it is also the oldest freshwater lake. It is more then 25 million years old, and holds about 20% of the world’s surface freshwater. Peter Rona from the Institute of Marine and Coastal Sciences at Rutgers University in New Brunswick, New Jersey, is excited by the opportunity to investigate Lake Baikal’s unique geology.

“Baikal Lake is at the earliest stage of opening out into an ocean,” says Rona, who has worked with Sagalevich on dives in the mid-Atlantic. “At Lake Baikal, you could see in detail what actually happens in the initial stages of the sea-floor spreading process. In 200 million years, the lake could become another ocean.”

The team, which comprises around 30 international researchers and engineers, plans to explore the lake for about 1 month, says Nigmatulin, who joined the dive team today. "This is just the beginning," he says. "We plan to return to Baikal Lake in 2009, and then we will dive 60 times to the bottom." _ 

Update: One of the MIR submersibles reached the deepest point of Lake Baikal at 15.15 local time on 29 July, according to Robert Nigmatulin, head of the P. P. Shirshov Institute of Oceanology in Moscow, Russia. He told Nature that the research team had reached a depth of 1680 metres, some 40 metres deeper than expected. The expedition was interrupted on 30 July when a propeller on one of the submersibles broke during a storm, although Nigmatulin says that it should be repaired quickly and that the dive would resume on 31 July.

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