Origin of the lake The origin of Baikal still causes scientific disputes. The age of the lake scientists traditionally define in 25-35 million years. This fact also makes Baikal a unique natural object, since most lakes, especially of glacial origin, live on average 10-15 thousand years, and then fill with muddy sediments and waterlogged. However, there is also a version about the youth of Baikal, put forward by the doctor of geological and mineralogical sciences A. V. Tatarinov in 2009, which received indirect confirmation during the second stage of the expedition "Worlds" on Baikal. In particular, the activity of mud volcanoes on the bottom of Lake Baikal allows scientists to assume that the current shoreline of the lake is only 8 thousand years, and the deep-water part is 150 thousand years. Undoubtedly, only that the lake is located in a rift basin and similar in structure, for example, to the Dead Sea basin. Some researchers explain the formation of Baikal by its location in the zone of the transform fault, others suggest the presence of a mantle plume near Baikal, while others explain the formation of the depression by passive rifting as a result of the collision of the Eurasian plate and Hindustan. Be that as it may, the transformation of Lake Baikal continues to this day - in the vicinity of the lake earthquakes are constantly occurring. There are suggestions that the subsidence of the depression is associated with the formation of vacuum foci due to the outflow of basalts to the surface (Quaternary period).
Seismic activity The Baikal region (the so-called Baikal rift zone) refers to areas with high seismicity: earthquakes occur regularly here, the strength of most of which is one or two points on the MSK-64 intensity scale. However, there are strong ones; So, in 1862 year with the ten-point Kudara earthquake in the northern part of the Selenga delta, a land of 200 km2 With 6-y uluses, in which lived 1300 people, and formed the Gulf of Failure. Strong earthquakes were also noted in 1903 year (Baikal), 1950 year (Mondinskoe), 1957 year (Muiskoye), 1959 year (Middle Baikal). The epicenter of the Middle Baikal earthquake was at the bottom of Lake Baikal in the vicinity of the village of Suhaya (south-east coast). His strength reached 9 points. In Ulan-Ude and Irkutsk, the force of the main shock reached 5-6 points, cracks and minor disruptions in buildings and structures were observed. Last strong earthquakes in Baikal occurred in August 2008 years (9 points) and in February 2010 years (6,1 points).
Geographical location and size of the basin Baikal is located in the center of the Asian continent at the border of the Irkutsk region and the Republic of Buryatia in the Russian Federation. The lake stretches from the north-east to the south-west at 620 km in the form of a giant crescent. The width of the Baikal ranges from 24 to 79 km. The bottom of Baikal is at 1167 meters below the level of the World Ocean, and the mirror of its waters is an 453 meter higher. The area of the Baikal water surface is 31 722 km2 (Excluding islands), which is roughly equal to the area of countries such as Belgium, the Netherlands or Denmark. According to the area of the watermark, Lake Baikal occupies the sixth place among the largest lakes in the world. The length of the coastline is 2100 km. The lake is located in a peculiar basin, surrounded on all sides by mountain ridges and hills. At the same time, the western coast is rocky and precipitous, the relief of the east coast is more gentle (in some places the mountains retreat from the coast for tens of kilometers).
Depths Baikal is the deepest lake on Earth. The current value of the maximum depth of the lake - 1642 m - was established in 1983 by LG Kolotilo and AI Sulimov during the hydrographic work of the expedition of the USSR GUNiO of the USSR at the point with coordinates 53 ° 14'59 "p. W. 108 ° 05'11 "in. (G) (O). & Lt; / RTI & gt; The maximum depth was plotted on maps in 1992 and confirmed in 2002 as a result of the joint Belgian-Spanish-Russian project to create a new bathymetric map of Baikal, when the depths in 1 312 788 points of the lake water were digitized (the depth values were obtained as a result of recalculation Acoustic sounding data combined with additional bathymetric information, including echolocation and seismic profiling, one of the authors of the discovery of maximum depth, LG Kolotilo , Was a participant in this project). If you consider that the water surface of the lake is at an altitude of 455,5 m above sea level, the lower point of the basin lies at 1186,5 m below the level of the world ocean, which makes the bowl of Lake Baikal also one of the deepest continental depressions. The average depth of the lake is also very high - 744,4 m. It exceeds the maximum depths of many very deep lakes. Besides Lake Baikal on Earth, only two lakes have a depth of more than 1000 meters: Tanganyika (1470 m) and the Caspian Sea (1025 m). (According to some data, the subglacial Lake Vostok in Antarctica has a depth of more than 1200 m, but it must be taken into account that this subglacial "lake" is not a lake in the sense we are used to, since over water four kilometers of ice and it is a sort of closed capacity , Where the water is under enormous pressure, and the "surface" or "level" of water in different parts of this "lake" differs by more than 400 meters.Thus, the concept of "depth" for the subglacial Lake Vostok is fundamentally different from the depth of "ordinary" lakes ).
Свойства воды The main properties of Baikal water can be briefly characterized as follows: there are very few dissolved and suspended mineral substances, negligible organic impurities, plenty of oxygen. The water in Baikal is cold. The temperature of the surface layers even in summer does not exceed + 8 ... + 9 ° C, in separate bays - + 15 ° C. The temperature of the deep layers is about + 4 ° C. The maximum fixed temperature in individual bays is + 23 ° C. The water in the lake is so transparent that individual stones and various objects can be seen at a depth of 40 m. At this time Baikal water is blue. In the summer and autumn, when the mass of plant and animal organisms develops in the sun-warmed water, its transparency decreases to 8-10 m, and the color becomes blue-green and green. The purest and most transparent water of Baikal contains so few mineral salts (96,7 mg / l) that can be used instead of distilled.
Bottom relief The bottom of Lake Baikal has a pronounced relief. Along the entire coast of Lake Baikal, coastal shallows (shelves) and underwater slopes are more or less developed; The bed of the three main basins of the lake is expressed; There are underwater banks and even underwater ridges. The basin of Lake Baikal is divided into three basins: the Southern, Middle and Northern, separated from each other by two ridges - the Academic and the Selenginsk. The most expressive is the Academic Range, stretching from Olkhon Island to Ushkan Island, which is its highest part. Its length is about 100 km, the maximum height above the bottom of Baikal is 1848 m. The thickness of bottom sediments in Lake Baikal reaches about 6 thousand meters, and, as established by gravimetric survey, one of the highest mountains on the Earth, with a height of more than 7000 m, is flooded in Baikal.
Climatic features The Baikal water mass influences the climate of the coastal territory. Winter is softer here, and summer is cooler. The arrival of spring on Lake Baikal is delayed by 10-15 days compared to the adjacent areas, and autumn is often quite long. The Baikal region is characterized by a large total duration of sunshine. For example, in the village of Bolshoe Goloustnoye it reaches 2524 hours, which is more than in the Black Sea resorts, and is a record for Russia. Days without the sun in the year in this same place is only 37, and on the island of Olkhon - 48. Special features of climate are caused by Baikal winds, which have their own names - barguzin, sarma, top coat, kultuk.
Flora and fauna According to the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences, 2630 species and varieties of plants and animals, 2 / 3 of which are endemic, inhabit the Baikal, that is, they live only in this reservoir. These include about 1000 endemic species, 96 genera, 11 families and subfamilies-endemics. 27 species of Baikal fish are nowhere to be found. Such an abundance of living organisms is explained by the high oxygen content in the entire thickness of Baikal water. The crustacean epishura, the endemic of Lake Baikal, is up to 80% of the zooplankton biomass of the lake and is the most important link in the food chain of the reservoir. It performs the function of a filter: it passes water through itself, purifying it. Baikal oligochaetes, 84,5% of which are endemics, constitute up to 70-90% of zoobenthos biomass and play an important role in the processes of lake self-purification and as a fodder base for benthophagous fish and predatory invertebrates. They participate in aeration of soils and mineralization of organic substances.
The most interesting in Baikal is the viviparous fish golomyanka, whose body contains up to 30% of fat. It surprises biologists with daily fodder migrations from the depths in shallow water. Among the fish in Baikal are Baikal omul, grayling, whitefish, Baikal sturgeon (Acipenser baeri baicalensis), burbot, taimen, pike and others. Baikal is unique among the lakes by the fact that at great depths freshwater sponges grow here.