During the inaugural submersion they went almost a kilometre deep.

Mir series capsules are unique. No other existing submersible can go so deep – and this ability could prove useful in more ways than one.

The Mir-2 mini-submarine is lowereded into the waters of Russia's lake Baikal on July 29, 2008   AFP Photo / Dmitry Kostyukov

Last year the MIR capsules were close to breaking the world record for the deepest freshwater dive. This time they have every chance of succeeding. They can descend to depths greater than 6,000 metres.

The Mir-1 and Mir-2 submersibles were built in 1987 by Finnish firm Rauma-Repola, according to the specifications of the Institute of Oceanography. They can dive up to 6,000 meters, which makes about 98% of the Earth’s sea and lake beds accessible to them. The vehicles are manned by three people each and normally stay underwater for a maximum of 24 hours, although in emergencies there is enough air for three days. The Mirs are 7.8 meters long, 3.8 meters wide and 3 meters high. They have a maximum speed of 5 knots.

“Perhaps, France will turn to us for help to find the flight data recorders from the crashed plane near Brazil. We would be ready to help and respond quickly,” the Head of Baikal Fund, Mikhail Slipenchuk, told RT.

But no request has been lodged yet, so the Baikal expedition started as scheduled.

International team

The $8-million research program, the second in as many years, has been organized by Russia’s Academy of Science, but the expedition team is international.

The purpose of the costly dives is to study one of the most thrilling natural wonders. Lake Baikal contains 83% of Russia’s and 20% of the world’s fresh water reserves.

This year’s research covers a wide range of interests. A deep-water probe will dive close to the epicenter of a major earthquake that took place on August 27, 2008.

As well as exploration of underwater gas hydrates, there’ll be ecological research into the impact of the now-closed Baikal pulp and paper plant. Scientists will also conduct structural tests at a place where several Trans-Siberian trains derailed and fell into the water a century ago.

The expedition is also expected to conduct dives in the middle section of Baikal to take a closer look at the Academic Ridge that forms Olkhon, Ushkanyikh and Svyatoy Nos islands.

MIR submersibles will also conduct tests to see if there are oil reserves beneath the lake.

For the first time in history, manned mobile submersibles, capable of geophysical exploration, will probe the extreme northern part of Baikal, making dives in the Barguzin reserve. This area of the lake, around Frolikh Bay near the mysterious Rytogo cape, remains largely unchartered. According to the legends of the indigenous Buryat people, it is a “fearful and holy place where angry gods dwell”.

Shocking discoveries

Last year the manned vehicle Mir touched the lake’s bottom for the first time in history to shatter the myth that Baikal had been heavily polluted by local industry – the water was found to be much cleaner than expected.

About 52 dives were completed in last year’s expedition, during the course of which, researchers discovered that the lake is growing by some two centimetres annually.

Director of the Baikal Museum, Vladimir Fialkov, says Baikal remains one of the cleanest bodies of water in the world.

“There are only 100 milligrams of salt per liter. But the Lake could be polluted if we do not treat it properly. It is by far the biggest natural laboratory in the world,” he says.

Lake Baikal consists of three main water basins. Their waters do not mix. And the water at the depth of 600 metres is some 400 years old.

Also, few people know that there are several natural oilfields at the bottom of the late, but a certain species of crustacean feeds off the carbohydrates and so completely cleans the water.

“Some four tons of oil are spruced into the waters of Baikal from its bottom every year, but no oil spill has appeared on the surface as of yet. That means that microorganisms simply eat it,” the head of the dive team, Sergey Smolitsky, says.

However, scientists say there is no question of extracting oil from any of the reserves. Oil from Baikal will take a thousand or so years to become mature enough for industrial extraction. So for now, it’s just food for the local fauna.