Caspian Sea in Kazakhstan
Largest closed reservoir in the world. Kazakhstan Ecology
The Caspian Sea is the largest closed reservoir in the world, which washes the western part of Kazakhstan. The name of the Sea is connected with the Caspii tribes who had settled these shores from time immemorial. It had had such names as Girkanskoye, Khazarskoye, and Khvalynskoye. The first mention of the Caspian Sea and its tribes was in the works of Gerodot. The document about the Russian navigators' visit to the Caspian Sea and their sailing is dated back to the 9th-10th centuries. At the beginning of the 18th century Peter I had begun the constant exploration of the Caspian Sea (through the expeditions of Bekovich-Cherkasky A. and others). Then Soimonov I. F., Ivashinsev N. A., Pallas P. S., Gmelin S. G., Karelin G. S., and others began research of the Caspian Sea.
The Caspian Sea stretches from north to south 1,200 km; its median width is 320 km, and the length of its shore line is about 7,000 km (6,000 km of which in the territory of Russia and other countries). The area of water territory is 371,000 sq km; the sea level is lower than the level of the ocean by 28.5 m (1971). Maximum depth is 1,025m (in the southern part); the Kazakhstan part is not deep, and the depth of the north Caspian is about 15-20 m. The largest gulfs are: Komsomolets, Mangyshlaksky (Magystau), Kenderli, Kazakhsky, and Kara-Bogas-Gol. The total territory of the 50 islands is about 350 sq.km.
The rivers Volga, Ural and Emba flow into the Caspian Sea from the northern side. By the bottom topography and hydrological features we can distinguish the Northern, Middle and Southern Caspian. At the bottom of the Caspian Sea are deposits of oil and gas. The Caspian Sea crosses several climate zones: in the northern part, continental, on the western, temperate-warm, in the southwestern, wet-subtropical, and in the east, dry-steppe zone.
The northern part is differentiated by the sudden variability of the air temperature and lack of atmospheric precipitation. In the northern and middle parts from October-April the wind blows from the east, from May-September the monsoon wind blows from the northwestern part to the south, on the eastern middle parts and in the northwestern and north parts there are winds, the speed of which exceeds 24 m/s. Average temperature of July and August is +24°C - +26°C, the absolute maximum is +44°C in the east.
In winter months the temperature changes from -10°C in the north to -12°C in the south. About 200 mm of precipitation falls over the Sea. The average value of evaporation is 1000mm per year. Average temperature of the water surface is +24°C - +26°C in summer, and in the southern part is +29°C. Average temperature of the water in the north is -0.5C in winter, in the middle part from -3°C to -7°C, and in the south -8°C -10°C. In the north the water surface freezes from November to March, and the ice is 2 m thick. Average water salinity is 12.7-12.8%, on the eastern coast is 13.2%, in the closest parts to the Volga and Ural mouth is 0.1-0.2%. The sea level sometimes rises and falls by 2-2.5m . The total seasonal fluctuation is about 30 cm. It is known that the lowest sea level occurred during the 6th-7th centuries (to 2-4 m lower than the present day).
The last falling of the sea level occurred between 1929 and 1957. The falling of the sea level was the result of the dry climate, and the building of the largest hydro-mechanical and irrigation structures on the river. Flora and fauna of the Caspian Sea are comparatively scarce. More than 500 kinds of plants, 854 kinds of fishes and animals, and a few kinds of aquatic birds dwell here. There are mostly near large populated areas near the Caspian Sea such as: Guriev, Shevchenko, Eraliev, Balykshy, Ganushkino etc, and important economic regions.
Charasteristics and ecology.
The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, though it is not a freshwater lake. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it is endothecia, i.e. there is no natural outflow (other than by evaporation). Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the ecstatic level of the world's oceans.
The Caspian became landlocked about 5.5 million years ago. The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians claim that a medieval rising of the Caspian caused the coastal towns of Khazaria, such as Atil, to flood. In 2004, the water level is -28 meters, or 28 meters below sea level. Over the centuries, the Caspian Sea levels have changed in synchronicity with the estimated discharge of the Volga, which in turn depends on rainfall levels in its vast catchment basin. Precipitation is related to variations in the amount of North Atlantic depressions that reach the interior, and they in turn are affected by cycles of the North Atlantic Oscillation. Thus levels in the Caspian Sea relate to atmospheric conditions in the North Atlantic thousands of miles to the north and west.
Recently discovered huge oil fields also lie beneath the Caspian Sea, though further exploration is needed to define the full extent of the oil potential in this part of the world. The main problem is the status of the Caspian Sea and the establishment of the water boundaries between the five riparian countries. Oil exploration around the sea began in the mid-1870s in the Baku region of Azerbaijan. By the turn of the twentieth century, its contribution to the world's total oil supply was estimated at 10%.
The USSR's Republic of Kazakhstan began in 1979 to exploit a major oil reserve along the Caspian. Since then, estimates of oil and natural gas reserves have grown sharply, with each of the littoral states keen on exploiting those reserves for export. Today, several foreign oil and gas companies have entered into various arrangements with the littoral states for exploration, production and transport of oil and gas resources with the hope of being able to export large quantities to markets around the globe. Oil and gas extraction, along with transportation and industrial production, has been the source of severe air, water, and soil pollution in the Caspian region. Systematic water sampling in different parts of the Caspian basin, it shows contamination from phenols, oil products, and other sources. Mineral deposit exploration, particularly oil extraction and pipeline construction, have contributed to the pollution of about 30,000 hectares of land.