Diving to the Bottom
Tuesday, August 12, 2008 - Ehud Rattner
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In an adventure worthy of Jules Verne, the team used the manned submersibles MIR 1 and MIR 2 — already famous for their performance in the documentary on the Titanic – to achieve this astounding feat. In fact, the surmised depth was 1,637 meters but during the diving the scientists discovered that their destination was deeper. However, the expedition was interrupted a day later, on July 30, when a propeller on one of the submersibles broke during a storm. According to Nigmatulin, MIR’s broken propeller was repaired quickly and the dive has resumed on July 31.
Lake Baikal is not only the deepest lake in the world, it is also the oldest freshwater lake, thought to be over 25 million years old. Furthermore, it 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,” she says. “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 one month, says Robert Nigmatulin, head of the P. P. Shirshov Institute of Oceanology, who joined the dive team only recently. “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.” Along the team is Artur Chilingaro, a member of the team that used MIR 1 to plant Russia’s flag on the seabed more than 4,200 meters below the North Pole in August 2007.
The submersibles used are capable of reaching depths of 6,000 meters, 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 meters to ensure that deeper dives can be safely controlled. During the planned thirty dives, the scientists intend to take water and sediment samples from Lake Baikal and hunt for hydrothermal vents that spew superheated water into the lake; another objective is the collection of gas hydrate deposits, located 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 meters below the lakebed 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.
TFOT has also covered the generation of unlimited solar energy from the ocean, using ocean thermal energy conversion and the solar powered underwater robot, developed by the Autonomous Undersea Systems Institute. Other related TFOT stories include the Thermal Glider, an autonomous underwater vehicle powered by “green” energy, and sQuba, which is the world's first “green” diving car.
For more information about its mission, see Deep Ocean Expeditions’s website.