Geography and hydrography:
Lake Baikal was known as the "North Sea" in historical Chinese texts. It was situated in the then Xiongnu territory and very little was known about the lake, until the Trans-Siberian railway was built between 1896 and 1902. The scenic railway loop encircling Lake Baikal required 200 bridges and 33 tunnels. As it was being built, a large hydrogeographical expedition headed by F.K. Drizhenko produced the first detailed atlas of the contours of Baikal's depths. The atlas demonstrated that Lake Baikal has more water than all of North America's Great Lakes combined - 23,600 cubic kilometers (5,700 cu mi), about 20% of the total unfrozen fresh surface water on the earth. However, in surface area, it is exceeded by the much shallower Great Lakes, Superior, Huron and Michigan, in North America, as well as by the relatively shallow Lake Victoria in East Africa. Known as the "Galápagos of Russia", its age and isolation have produced some of the world's richest and most unusual freshwater fauna, which is of exceptional value to evolutionary science.
Lake Baikal is in a rift valley, created by the Baikal Rift Zone, where the crust of the earth is pulling apart. At 636 kilometers (395 mi) long and 79 kilometers (49 mi) wide, Lake Baikal has the largest surface area of any freshwater lake in Asia (31,494 km2/12,160 sq mi) and is the deepest lake in the world (1,637 m/5,370 ft). The bottom of the lake is 1,371 meters (4,500 ft) below sea level, but below this lies some 7 kilometers (4.3 mi) of sediment, placing the rift floor some 8-9 kilometers (more than 5 miles) below the surface: the deepest continental rift on Earth. In geological terms, the rift is young and active-it widens about two centimeters per year. The fault zone is also seismically active; there are hot springs in the area and notable earthquakes every few years. It drains into the Angara tributary of the Yenisei.
Its age is estimated at 25-30 million years, making it one of the most ancient lakes in geological history. It is unique among large, high-latitude lakes, in that its sediments have not been scoured by overriding continental ice sheets. U.S. and Russian studies of core sediment in the 1990s provide a detailed record of climatic variation over the past 250,000 years. Longer and deeper sediment cores are expected in the near future. Lake Baikal is furthermore the only confined fresh water lake in which direct and indirect evidence of gas hydrates exists.
The lake is completely surrounded by mountains. The Baikal Mountains on the north shore and the taiga are technically protected as a national park. It contains 22 islands; the largest, Olkhon, is 72 kilometers (45 mi) long. The lake is fed by as many as three hundred and thirty inflowing rivers. The main ones draining directly into Baikal are the Selenga River, the Barguzin River, the Upper Angara River, the Turka River, the Sarma River and the Snezhnaya River. It is drained through a single outlet, the Angara River.
Despite its great depth, the lake's waters are well-mixed and well-oxygenated throughout the water column, compared to the stratification that occurs in such bodies of water as Lake Tanganyika and the Black Sea.
Olkhon, the largest island in Lake Baikal, is the fourth-largest lake-bound island in the world.
The extent of biodiversity present in Lake Baikal is equaled by few other lakes. Lake Baikal hosts 1,085 species of plants and 1,550 species and varieties of animals. More than 80% of the animals are endemic. Epischura baikalensis is endemic to Lake Baikal and the dominating zooplankton species there: 80 to 90 percent of total biomass. The Baikal Seal or nerpa (Phoca sibirica) is found throughout Lake Baikal. It is one of only three entirely freshwater seal species in the world, the other being the two subspecies of freshwater Ringed Seal. Perhaps the most important local species is the omul (Coregonus autumnalis migratorius), a smallish endemic salmonid. It is caught, smoked and then sold widely in markets around the lake.
Of particular note are the two species of golomyanka or Baikal oil fish (Comephorus baicalensis and C. dybowskii). These long-finned, translucent fish normally live in depths of 200 to 500 meters (660-1,600 ft) and are the primary prey of the Baikal seal, representing the largest fish biomass in the lake. They are famous for disintegrating into a pool of oil and bones when exposed to sunlight. The Baikal grayling (Thymallus arcticus baicalensis), a fast swimming salmonid, popular among anglers and the Baikal sturgeon (Asipenser baerri baicalensis), are both important endemic species with commercial value.
Bear and deer are common and hunted along Baikal shores.
he lake, called "the Pearl of Siberia", drew investors from the tourist industry as energy revenues sparked an economic boom. Viktor Grigorov's Grand Baikal in Irkutsk is one of the investors, who planned to build three hotels creating 570 jobs. In 2007, the Russian government declared the Baikal region a special economic zone. The popular resort of Listvyanka is home to the seven-story Hotel Mayak. Baikal was also declared a UNESCO World Heritage site in 1996. Rosatom plans to build a laboratory in Baikal, in conjunction with an international uranium plant and to invest $2.5bn in the region and create 2,000 jobs in the city of Angarsk.