Why is the Caspian Sea considered a lake? Rivers flowing into the Caspian Sea: list, description, characteristics Which countries surround the Caspian Sea

, Kazakhstan, Turkmenistan, Iran, Azerbaijan

Geographical position

Caspian Sea - view from space.

The Caspian Sea is conventionally divided according to physical and geographical conditions into 3 parts - Northern Caspian, Middle Caspian and Southern Caspian. The conditional border between the Northern and Middle Caspian runs along the line of the island. Chechen - Cape Tyub-Karagansky, between the Middle and Southern Caspian Sea - along the line of the island. Residential - Cape Gan-Gulu. The area of the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

Coast of the Caspian Sea

Coast of the Caspian Sea in Turkmenistan

The territory adjacent to the Caspian Sea is called the Caspian region.

Peninsulas of the Caspian Sea

Ashur-Ada
Garasu
Zyanbil
Khara-Zira
Sengi-Mugan
Chygyl

Bays of the Caspian Sea

Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, the length of the coastline is about 1930 kilometers
Kazakhstan - in the north, northeast and east, the length of the coastline is about 2320 kilometers
Turkmenistan - in the southeast, the length of the coastline is about 650 kilometers
Iran - in the south, the length of the coastline is about 1000 kilometers
Azerbaijan - in the southwest, the length of the coastline is about 800 kilometers

Cities on the Caspian Sea coast

On the Russian coast are the cities of Lagan, Makhachkala, Kaspiysk, Izberbash and the southernmost city of Russia, Derbent. Astrakhan is also considered a port city of the Caspian Sea, which, however, is not located on the shores of the Caspian Sea, but in the Volga delta, 60 kilometers from the northern coast of the Caspian Sea.

Physiography

Area, depth, volume of water

The area and volume of water in the Caspian Sea varies significantly depending on fluctuations in water levels. At a water level of −26.75 m, the area is approximately 371,000 square kilometers, the volume of water is 78,648 cubic kilometers, which is approximately 44% of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface level. In terms of maximum depth, the Caspian Sea is second only to Baikal (1620 m) and Tanganyika (1435 m). The average depth of the Caspian Sea, calculated from the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

Water level fluctuations

Vegetable world

The flora of the Caspian Sea and its coast is represented by 728 species. The predominant plants in the Caspian Sea are algae - blue-green, diatoms, red, brown, characeae and others, and flowering plants - zoster and ruppia. In origin, the flora is predominantly of Neogene age, but some plants were brought into the Caspian Sea by humans deliberately or on the bottoms of ships.

History of the Caspian Sea

Origin of the Caspian Sea

Anthropological and cultural history of the Caspian Sea

Finds in the Khuto Cave off the southern coast of the Caspian Sea indicate that man lived in these areas approximately 75 thousand years ago. The first mentions of the Caspian Sea and the tribes living on its coast are found in Herodotus. Around the V-II centuries. BC e. Saka tribes lived on the Caspian coast. Later, during the period of settlement of the Turks, in the period of the 4th-5th centuries. n. e. Talysh tribes (Talysh) lived here. According to ancient Armenian and Iranian manuscripts, Russians sailed the Caspian Sea from the 9th-10th centuries.

Research of the Caspian Sea

Research of the Caspian Sea was started by Peter the Great, when, on his order, an expedition was organized in 1714-1715 under the leadership of A. Bekovich-Cherkassky. In the 1720s, hydrographic research was continued by the expedition of Karl von Werden and F. I. Soimonov, and later by I. V. Tokmachev, M. I. Voinovich and other researchers. At the beginning of the 19th century, instrumental surveys of the shores were carried out by I. F. Kolodkin, in the mid-19th century. - instrumental geographical survey under the direction of N. A. Ivashintsev. Since 1866, for more than 50 years, expeditionary research on the hydrology and hydrobiology of the Caspian Sea was carried out under the leadership of N. M. Knipovich. In 1897, the Astrakhan Research Station was founded. In the first decades of Soviet power, geological research by I.M. Gubkin and other Soviet geologists was actively carried out in the Caspian Sea, mainly aimed at searching for oil, as well as research into the study of water balance and level fluctuations in the Caspian Sea.

Economy of the Caspian Sea

Mining of oil and gas

Many oil and gas fields are being developed in the Caspian Sea. Proven oil resources in the Caspian Sea are about 10 billion tons, total oil and gas condensate resources are estimated at 18-20 billion tons.

Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf near Baku. In the second half of the 19th century, oil production began on an industrial scale on the Absheron Peninsula, and then in other territories.

Shipping

Shipping is developed in the Caspian Sea. There are ferry crossings on the Caspian Sea, in particular, Baku - Turkmenbashi, Baku - Aktau, Makhachkala - Aktau. The Caspian Sea has a shipping connection with the Sea of Azov through the Volga, Don and Volga-Don Canal rivers.

Fishing and seafood production

Fishing (sturgeon, bream, carp, pike perch, sprat), caviar production, as well as seal fishing. More than 90 percent of the world's sturgeon catch occurs in the Caspian Sea. In addition to industrial mining, illegal fishing of sturgeon and their caviar flourishes in the Caspian Sea.

Recreational resources

The natural environment of the Caspian coast with sandy beaches, mineral waters and healing mud in the coastal zone creates good conditions for recreation and treatment. At the same time, in terms of the degree of development of resorts and the tourism industry, the Caspian coast is noticeably inferior to the Black Sea coast of the Caucasus. At the same time, in recent years, the tourism industry has been actively developing on the coasts of Azerbaijan, Iran, Turkmenistan and Russian Dagestan. In Azerbaijan, the resort area in the Baku region is actively developing. At the moment, a world-class resort has been created in Amburan, another modern tourist complex is being built in the area of the village of Nardaran, and holidays in the sanatoriums of the villages of Bilgah and Zagulba are very popular. A resort area is also being developed in Nabran, in northern Azerbaijan. However, high prices, a generally low level of service and a lack of advertising lead to the fact that there are almost no foreign tourists at the Caspian resorts. The development of the tourism industry in Turkmenistan is hampered by a long-term policy of isolation, in Iran - Sharia laws, due to which mass holidays of foreign tourists on the Caspian coast of Iran are impossible.

Ecological problems

Environmental problems of the Caspian Sea are associated with water pollution as a result of oil production and transportation on the continental shelf, the flow of pollutants from the Volga and other rivers flowing into the Caspian Sea, the life activity of coastal cities, as well as the flooding of individual objects due to rising levels of the Caspian Sea. Predatory production of sturgeon and their caviar, rampant poaching lead to a decrease in the number of sturgeon and to forced restrictions on their production and export.

International status of the Caspian Sea

Legal status of the Caspian Sea

After the collapse of the USSR, the division of the Caspian Sea has long been and still remains the subject of unresolved disagreements related to the division of Caspian shelf resources - oil and gas, as well as biological resources. For a long time, negotiations were ongoing between the Caspian states on the status of the Caspian Sea - Azerbaijan, Kazakhstan and Turkmenistan insisted on dividing the Caspian along the median line, Iran insisted on dividing the Caspian by one-fifth between all Caspian states.

In relation to the Caspian Sea, the key is the physical-geographical circumstance that it is a closed inland body of water that does not have a natural connection with the World Ocean. Accordingly, the norms and concepts of international maritime law, in particular, the provisions of the UN Convention on the Law of the Sea of 1982, should not be automatically applied to the Caspian Sea. Based on this, in relation to the Caspian Sea it would be unlawful to apply such concepts as “territorial sea”, “exclusive economic zone", "continental shelf", etc.

The current legal regime of the Caspian Sea was established by the Soviet-Iranian treaties of 1921 and 1940. These treaties provide for freedom of navigation throughout the sea, freedom of fishing with the exception of ten-mile national fishing zones and a ban on vessels flying the flag of non-Caspian states sailing in its waters.

Negotiations on the legal status of the Caspian Sea are currently ongoing.

Delineation of sections of the Caspian seabed for subsoil use

The Russian Federation concluded an agreement with Kazakhstan on delimiting the bottom of the northern part of the Caspian Sea in order to exercise sovereign rights to subsoil use (dated July 6, 1998 and the Protocol thereto dated May 13, 2002), an agreement with Azerbaijan on delimiting adjacent areas of the bottom of the northern part of the Caspian Sea (dated September 23, 2002), as well as the trilateral Russian-Azerbaijani-Kazakh agreement on the junction point of the demarcation lines of adjacent sections of the bottom of the Caspian Sea (dated May 14, 2003), which established the geographical coordinates of the dividing lines limiting the sections of the bottom within which the parties exercise their sovereign rights in the field of exploration and production of mineral resources.

CASPIAN SEA (Caspian), the largest enclosed body of water on the globe, an endorheic brackish lake. Located on the southern border of Asia and Europe, it washes the shores of Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Due to its size, unique natural conditions and the complexity of hydrological processes, the Caspian Sea is usually classified as a closed inland sea.

The Caspian Sea is located in a vast area of internal drainage and occupies a deep tectonic depression. The water level in the sea is about 27 m below the level of the World Ocean, the area is about 390 thousand km 2, the volume is about 78 thousand km 3. The greatest depth is 1025 m. With a width of 200 to 400 km, the sea extends along the meridian for 1030 km.

The largest bays: in the east - Mangyshlaksky, Kara-Bogaz-Gol, Turkmenbashi (Krasnovodsky), Turkmensky; in the west - Kizlyarsky, Agrakhansky, Kizilagaj, Baku Bay; in the south there are shallow lagoons. There are many islands in the Caspian Sea, but almost all of them are small, with a total area of less than 2 thousand km 2. In the northern part there are numerous small islands adjacent to the Volga delta; larger ones are Kulaly, Morskoy, Tyuleniy, Chechen. Off the western coast is the Absheron archipelago, to the south lie the islands of the Baku archipelago, off the eastern coast is the narrow island of Ogurchinsky, stretched from north to south.

The northern shores of the Caspian Sea are low-lying and very sloping, characterized by the widespread development of drying areas formed as a result of surge phenomena; deltaic shores are also developed here (deltas of the Volga, Ural, Terek) with an abundant supply of terrigenous material; the Volga delta with extensive reed thickets stands out. The western shores are abrasive, south of the Absheron Peninsula, mostly accumulative deltaic type with numerous bay bars and spits. The southern shores are low. The eastern shores are mostly deserted and low-lying, composed of sand.

Relief and geological structure of the bottom.

The Caspian Sea is located in a zone of increased seismic activity. In the city of Krasnovodsk (now Turkmenbashi) in 1895, a powerful earthquake measuring 8.2 on the Richter scale occurred. On the islands and coast of the southern part of the sea, eruptions of mud volcanoes are often observed, leading to the formation of new shoals, banks and small islands, which are eroded by waves and appear again.

Based on the peculiarities of physical-geographical conditions and the nature of the bottom topography in the Caspian Sea, it is customary to distinguish the Northern, Middle and Southern Caspian Seas. The Northern Caspian Sea is distinguished by exceptionally shallow waters, located entirely within the shelf with average depths of 4-5 m. Even small changes in the level here on low-lying coasts lead to significant fluctuations in the area of the water surface, therefore the boundaries of the sea in the northeastern part are shown with a dotted line on small-scale maps. The greatest depths (about 20 m) are observed only near the conventional border with the Middle Caspian, which is drawn along a line connecting the island of Chechen (north of the Agrakhan Peninsula) with Cape Tyub-Karagan on the Mangyshlak Peninsula. The Derbent depression (maximum depth 788 m) stands out in the bottom topography of the Middle Caspian Sea. The border between the Middle and Southern Caspian Sea passes over the Absheron threshold with depths of up to 180 m along a line from Chilov Island (east of the Absheron Peninsula) to Cape Kuuli (Turkmenistan). The Southern Caspian basin is the most extensive area of the sea with the greatest depths; almost 2/3 of the waters of the Caspian Sea are concentrated here, 1/3 is in the Middle Caspian, and less than 1% of the Caspian waters are located in the Northern Caspian due to shallow depths. In general, the topography of the Caspian Sea bottom is dominated by shelf areas (the entire northern part and a wide strip along the eastern coast of the sea). The continental slope is most pronounced on the western slope of the Derbent Basin and almost along the entire perimeter of the South Caspian Basin. On the shelf, terrigenous-shelly sands, shell, and oolitic sands are common; deep-sea areas of the bottom are covered with siltstone and silty sediments with a high content of calcium carbonate. In some areas of the bottom, bedrock of Neogene age is exposed. Mirabilite accumulates in the Kara-Bogaz-Gol Bay.

Tectonically, within the Northern Caspian Sea, the southern part of the Caspian syneclise of the Eastern European Platform is distinguished, which in the south is framed by the Astrakhan-Aktobe zone, composed of Devonian-Lower Permian carbonate rocks that lie on a volcanic base and contain large deposits of oil and natural combustible gas. From the southwest, Paleozoic folded formations of the Donetsk-Caspian zone (or Karpinsky ridge) are thrust onto the syneclise, which is a protrusion of the foundation of the young Scythian (in the west) and Turanian (in the east) platforms, which are separated at the bottom of the Caspian Sea by the Agrakhan-Gurievsky fault (left shear) of northeastern strike. The Middle Caspian mainly belongs to the Turanian platform, and its southwestern margin (including the Derbent depression) is a continuation of the Terek-Caspian foredeep of the Greater Caucasus fold system. The sedimentary cover of the platform and trough, composed of Jurassic and younger sediments, contains deposits of oil and combustible gas in local uplifts. The Absheron threshold, separating the Middle Caspian from the South, is a connecting link of the Cenozoic folded systems of the Greater Caucasus and Kopetdag. The South Caspian basin of the Caspian Sea with crust of oceanic or transitional type is filled with a thick (over 25 km) complex of Cenozoic sediments. Numerous large hydrocarbon deposits are concentrated in the South Caspian Basin.

Until the end of the Miocene, the Caspian Sea was a marginal sea of the ancient Tethys Ocean (from the Oligocene - the relict oceanic basin of the Paratethys). By the beginning of the Pliocene, it lost contact with the Black Sea. The Northern and Middle Caspian Seas were drained, and the paleo-Volga valley stretched through them, the delta of which was located in the Absheron Peninsula region. Delta sediments have become the main reservoir of oil and natural combustible gas deposits in Azerbaijan and Turkmenistan. In the late Pliocene, in connection with the Akchagyl transgression, the area of the Caspian Sea greatly increased and the connection with the World Ocean was temporarily resumed. The waters of the sea covered not only the bottom of the modern depression of the Caspian Sea, but also the adjacent territories. In Quaternary time, transgressions (Apsheron, Baku, Khazar, Khvalyn) alternated with regressions. The southern half of the Caspian Sea is located in a zone of increased seismic activity.

Climate. The Caspian Sea, strongly elongated from north to south, is located within several climatic zones. In the northern part the climate is temperate continental, on the west coast it is warm temperate, the southwestern and southern coasts lie within the subtropics, and on the east coast a desert climate prevails. In winter, over the Northern and Middle Caspian, the weather is formed under the influence of Arctic continental and sea air, and the Southern Caspian is often under the influence of southern cyclones. The weather in the west is unstable and rainy, in the east it is dry. In summer, the western and northwestern regions are influenced by the spurs of the Azores atmospheric maximum, and the southeastern ones are influenced by the Iran-Afghan minimum, which together creates dry, stable warm weather. Over the sea, winds prevail in the northern and northwestern (up to 40%) and southeastern (about 35%) directions. The average wind speed is about 6 m/s, in the central regions of the sea up to 7 m/s, in the area of the Absheron Peninsula - 8-9 m/s. Northern storm “Baku Nords” reach speeds of 20-25 m/s. The lowest average monthly air temperatures -10 °C are observed in January - February in the northeastern regions (in the most severe winters they reach -30 °C), in the southern regions 8-12 °C. In July - August, average monthly temperatures over the entire sea area are 25-26 °C, with a maximum of 44 °C on the east coast. The distribution of atmospheric precipitation is very uneven - from 100 mm per year on the eastern shores to 1700 mm in Lankaran. The open sea receives an average of about 200 mm of precipitation per year.

Hydrological regime. Changes in the water balance of an enclosed sea greatly influence changes in the volume of water and corresponding fluctuations in level. Average long-term components of the water balance of the Caspian Sea for the 1900-90s (km 3 /cm layer): river runoff 300/77, precipitation 77/20, underground runoff 4/1, evaporation 377/97, runoff to Kara-Bogaz- Gol 13/3, which forms a negative water balance of 9 km 3, or 3 cm of layer, per year. According to paleogeographic data, over the past 2000 years, the range of fluctuations in the level of the Caspian Sea has reached at least 7 m. Since the beginning of the 20th century, level fluctuations have shown a steady downward trend, as a result of which over 75 years the level dropped by 3.2 m and in 1977 reached -29 m (lowest position in the last 500 years). The sea surface area has decreased by more than 40 thousand km 2, which exceeds the area of the Sea of Azov. Since 1978, a rapid rise in level began, and by 1996 a mark of about -27 m relative to the level of the World Ocean was reached. In the modern era, fluctuations in the level of the Caspian Sea are determined mainly by fluctuations in climatic characteristics. Seasonal fluctuations in the level of the Caspian Sea are associated with the unevenness of river flow (primarily the Volga runoff), therefore the lowest level is observed in winter, the highest in summer. Short-term sharp changes in level are associated with surge phenomena; they are most pronounced in shallow northern areas and during storm surges can reach 3-4 m. Such surges cause flooding of large coastal areas of land. In the Middle and Southern Caspian Sea, surge fluctuations in level average 10-30 cm, under storm conditions - up to 1.5 m. The frequency of surges, depending on the region, is from one to 5 times a month, lasting up to one day. In the Caspian Sea, as in any closed body of water, seiche level fluctuations are observed in the form of standing waves with periods of 4-9 hours (wind) and 12 hours (tidal). The magnitude of seiche vibrations usually does not exceed 20-30 cm.

River flow in the Caspian Sea is distributed extremely unevenly. More than 130 rivers flow into the sea, which on average bring about 290 km 3 of fresh water per year. Up to 85% of the river flow falls on the Volga and the Urals and enters the shallow Northern Caspian Sea. The rivers of the western coast - Kura, Samur, Sulak, Terek, etc. - provide up to 10% of the flow. Another approximately 5% of fresh water is brought to the South Caspian by rivers on the Iranian coast. The eastern desert shores are completely deprived of constant fresh flow.

The average speed of wind currents is 15-20 cm/s, the highest - up to 70 cm/s. In the Northern Caspian Sea, the prevailing winds create a flow directed along the northwestern coast to the southwest. In the Middle Caspian, this current merges with the western branch of the local cyclonic circulation and continues to move along the western coast. Near the Absheron Peninsula the current bifurcates. Its part in the open sea flows into the cyclonic circulation of the Middle Caspian, and the coastal part goes around the shores of the Southern Caspian and turns north, joining the coastal current that goes around the entire eastern coast. The average state of movement of Caspian surface waters is often disturbed due to variability in wind conditions and other factors. Thus, in the northeastern shallow area, a local anticyclonic gyre may arise. Two anticyclonic eddies are often observed in the Southern Caspian Sea. In the Middle Caspian in the warm season, stable northwest winds create southerly transport along the eastern coast. In light winds and during calm weather, currents may have other directions.

Wind waves develop very strongly, since the prevailing winds have a long acceleration length. The disturbance develops mainly in the northwest and southeast directions. Strong storms are observed in the open waters of the Middle Caspian Sea, in the areas of Makhachkala, the Absheron Peninsula and the Mangyshlak Peninsula. The average wave height of greatest frequency is 1-1.5 m; at wind speeds of more than 15 m/s it increases to 2-3 m. The highest wave heights are recorded during strong storms in the area of the Neftyanye Kamni hydrometeorological station: annually 7-8 m, in some cases up to 10 m.

The water temperature on the sea surface in January - February in the Northern Caspian Sea is close to freezing temperature (about -0.2 - -0.3 °C) and gradually increases southward to 11 °C off the coast of Iran. In summer, surface waters warm up to 23-28 °C everywhere, except for the eastern shelf of the Middle Caspian Sea, where in July - August seasonal coastal upwelling develops and the surface water temperature drops to 12-17 °C. In winter, due to intense convective mixing, the water temperature changes little with depth. In summer, under the upper heated layer at horizons of 20-30 m, a seasonal thermocline (a layer of sharp temperature changes) is formed, separating deep cold waters from warm surface ones. In the bottom layers of water in deep-sea depressions, the temperature remains 4.5-5.5 °C all year round in the Middle Caspian and 5.8-6.5 °C in the Southern Caspian. Salinity in the Caspian Sea is almost 3 times lower than in open areas of the World Ocean, averaging 12.8-12.9‰. It should be especially emphasized that the salt composition of Caspian water is not completely identical to the composition of ocean waters, which is explained by the isolation of the sea from the ocean. The waters of the Caspian Sea are poorer in sodium salts and chlorides, but richer in carbonates and sulfates of calcium and magnesium due to the unique composition of salts entering the sea with river and underground runoff. The highest salinity variability is observed in the Northern Caspian, where in the estuarine areas of the Volga and Ural the water is fresh (less than 1‰), and as we move south, the salt content increases to 10-11‰ at the border with the Middle Caspian. The greatest horizontal salinity gradients are characteristic of the frontal zone between sea and river waters. The differences in salinity between the Middle and Southern Caspian Seas are small; salinity increases slightly from northwest to southeast, reaching 13.6‰ in the Turkmen Gulf (in Kara-Bogaz-Gol up to 300‰). Vertical changes in salinity are small and rarely exceed 0.3‰, which indicates good vertical mixing of waters. Water transparency varies widely from 0.2 m in the mouth areas of large rivers to 15-17 m in the central regions of the sea.

According to the ice regime, the Caspian Sea is classified as a partially frozen sea. Ice conditions are observed annually only in the northern regions. The Northern Caspian is completely covered by sea ice, the Middle Caspian is partially covered (only in severe winters). The average boundary of sea ice runs along an arc convex to the north, from the Agrakhan Peninsula in the west to the Tyub-Karagan Peninsula in the east. Ice formation usually begins in mid-November in the extreme northeast and gradually spreads to the southwest. In January, the entire Northern Caspian Sea is covered with ice, mostly fast ice (immobile). Drifting ice borders the fast ice with a strip 20-30 km wide. The average ice thickness is from 30 cm at the southern border to 60 cm in the northeastern regions of the Northern Caspian Sea, in hummocky accumulations - up to 1.5 m. The destruction of the ice cover begins in the 2nd half of February. In severe winters, drifting ice is carried south, along the western coast, sometimes to the Absheron Peninsula. At the beginning of April, the sea is completely free of ice cover.

History of the study . It is believed that the modern name of the Caspian Sea comes from the ancient Caspian tribes who inhabited the coastal areas in the 1st millennium BC; other historical names: Hyrkan (Irkan), Persian, Khazar, Khvalyn (Khvalis), Khorezm, Derbent. The first mention of the existence of the Caspian Sea dates back to the 5th century BC. Herodotus was one of the first to claim that this body of water is isolated, that is, it is a lake. In the works of Arab scientists of the Middle Ages there is information that in the 13th-16th centuries the Amu Darya partially flowed into this sea through one of its branches. The well-known numerous ancient Greek, Arabic, European, including Russian, maps of the Caspian Sea until the beginning of the 18th century did not reflect reality and were actually arbitrary drawings. By order of Tsar Peter I, in 1714-15, an expedition was organized under the leadership of A. Bekovich-Cherkassky, who explored the Caspian Sea, in particular its eastern shores. The first map, on which the contours of the coasts are close to modern ones, was compiled in 1720 using astronomical definitions by Russian military hydrographers F.I. Soimonov and K. Verdun. In 1731, Soimonov published the first atlas, and soon the first printed sailing guide of the Caspian Sea. A new edition of maps of the Caspian Sea with corrections and additions was carried out by Admiral A.I. Nagaev in 1760. The first information on the geology and biology of the Caspian Sea was published by S. G. Gmelin and P. S. Pallas. Hydrographic research in the 2nd half of the 18th century was continued by I.V. Tokmachev, M.I. Voinovich, and at the beginning of the 19th century by A.E. Kolodkin, who for the first time carried out instrumental compass surveying of the coast. In 1807, a new map of the Caspian Sea was published, compiled taking into account the latest inventories. In 1837, systematic instrumental observations of sea level fluctuations began in Baku. In 1847, the first complete description of the Kara-Bogaz-Gol Bay was made. In 1878, a General Map of the Caspian Sea was published, which reflected the results of the latest astronomical observations, hydrographic surveys and depth measurements. In 1866, 1904, 1912-13, 1914-15, under the leadership of N. M. Knipovich, expeditionary research was carried out on the hydrology and hydrobiology of the Caspian Sea; in 1934, the Commission for the Comprehensive Study of the Caspian Sea was created at the USSR Academy of Sciences. Soviet geologists I. made a great contribution to the study of the geological structure and oil content of the Absheron Peninsula and the geological history of the Caspian Sea. M. Gubkin, D. V. and V. D. Golubyatnikov, P. A. Pravoslavlev, V. P. Baturin, S. A. Kovalevsky; in the study of water balance and sea level fluctuations - B. A. Appolov, V. V. Valedinsky, K. P. Voskresensky, L.S. Berg. After the Great Patriotic War, systematic, comprehensive research was launched in the Caspian Sea, aimed at studying the hydrometeorological regime, biological conditions and geological structure of the sea.

In the 21st century in Russia, two large scientific centers are engaged in solving the problems of the Caspian Sea. The Caspian Marine Research Center (CaspMNRC), created in 1995 by decree of the Government of the Russian Federation, conducts research work in hydrometeorology, oceanography and ecology. The Caspian Research Institute of Fisheries (CaspNIRKH) traces its history back to the Astrakhan Research Station [established in 1897, since 1930 the Volga-Caspian Scientific Fisheries Station, since 1948 the Caspian Branch of the All-Russian Research Institute of Fisheries and Oceanography, since 1954 the Caspian Scientific Research Institute of Marine Fisheries and Oceanography (CaspNIRO), modern name since 1965]. CaspNIRH is developing the foundations for the conservation and rational use of biological resources of the Caspian Sea. It consists of 18 laboratories and scientific departments - in Astrakhan, Volgograd and Makhachkala. It has a scientific fleet of more than 20 vessels.

Economic use. The natural resources of the Caspian Sea are rich and varied. Significant hydrocarbon reserves are being actively developed by Russian, Kazakh, Azerbaijani and Turkmen oil and gas companies. There are huge reserves of mineral self-sedimented salts in the Kara-Bogaz-Gol Bay. The Caspian region is also known as a massive habitat for waterfowl and semi-aquatic birds. About 6 million migratory birds migrate across the Caspian Sea every year. In this regard, the Volga delta, Kyzylagaj, Northern Cheleken and Turkmenbashi bays are recognized as sites of international rank within the framework of the Ramsar Convention. The mouth areas of many rivers flowing into the sea have unique types of vegetation. The fauna of the Caspian Sea is represented by 1800 species of animals, of which 415 are vertebrate species. More than 100 species of fish live in the sea and river mouths. Marine species are of commercial importance - herring, sprat, gobies, sturgeon; freshwater - carp, perch; Arctic “invaders” - salmon, whitefish. Large ports: Astrakhan, Makhachkala in Russia; Aktau, Atyrau in Kazakhstan; Turkmenbashi in Turkmenistan; Bender-Torkemen, Bender-Anzeli in Iran; Baku in Azerbaijan.

Ecological state. The Caspian Sea is under powerful anthropogenic influence due to the intensive development of hydrocarbon deposits and the active development of fishing. In the 1980s, the Caspian Sea provided up to 80% of the world's sturgeon catch. Predatory fishing in recent decades, poaching and a sharp deterioration of the environmental situation have brought many valuable fish species to the brink of extinction. The living conditions of not only fish, but also birds and sea animals (Caspian seal) have deteriorated. Countries washed by the waters of the Caspian Sea are faced with the problem of creating a set of international measures to prevent pollution of the aquatic environment and developing the most effective environmental strategy for the near future. A stable ecological state is observed only in parts of the sea remote from the coast.

Lit.: Caspian Sea. M., 1969; Comprehensive studies of the Caspian Sea. M., 1970. Issue. 1; Gul K.K., Lappalainen T.N., Polushkin V.A. Caspian Sea. M., 1970; Zalogin B.S., Kosarev A.N. Seas. M., 1999; International tectonic map of the Caspian Sea and its frame / Ed. V. E. Khain, N. A. Bogdanov. M., 2003; Zonn I. S. Caspian Encyclopedia. M., 2004.

M. G. Deev; V. E. Khain (geological structure of the bottom).

(Caspian Sea) is the largest enclosed body of water on the globe, an endorheic brackish lake. Located on the southern border of Asia and Europe. Due to its size, unique natural conditions and the complexity of hydrological processes, it is usually classified as a closed inland sea. The water level in the Caspian Sea is about 27 meters below the level of the World Ocean, the area is about 390 thousand square kilometers, the volume is about 78 thousand cubic kilometers. The greatest depth is 1025 meters. With a width of 200 to 400 kilometers, the sea extends along the meridian for 1030 kilometers.

More than 130 rivers flow into the Caspian Sea, the largest of which is the Volga, which connects it with the World Ocean.

The Caspian region is rich in hydrocarbon reserves - oil and gas. Among the biological resources of the Caspian Sea, sturgeon are of particular value, forming the basis of the world stock and gene pool, preserved and reproducing on Earth.

Five states have a coastline with the Caspian Sea: Russia - in the west and northwest, Kazakhstan - in the north, northeast and east, Iran - in the south, Azerbaijan - in the southwest, Turkmenistan - in the southeast.

In Soviet times, the Caspian Sea was practically an internal body of water within the borders of the USSR and only in the south washed the shores of Iran. The status of the Caspian Sea as an internal (inland) body of water established by the Soviet-Iranian treaties was practically recognized by the entire international community of states and was confirmed in the doctrine of international law.

The question of determining the legal status of the Caspian Sea, when the emergence of new subjects of international law - Azerbaijan, Kazakhstan and Turkmenistan - raised the question of delimiting the Caspian Sea between five countries. The difficulties in determining the status of the Caspian Sea are associated, in particular, with its recognition as a lake or sea, the delimitation of which is regulated by various provisions of international law.

Currently, the legal regime of the Caspian Sea is determined by the Treaty between the RSFSR and Persia of February 26, 1921 and the Treaty on Trade and Navigation between the USSR and Iran of March 25, 1940. These documents, based on the principle of “common water,” provide for freedom of navigation and fishing for the Caspian states (in the latter case, with the exception of a 10-mile fishing zone), and a ban on the navigation of ships flying the flags of non-Caspian countries. At the same time, the agreements do not regulate issues of subsoil use, environmental protection and military activities. In addition, their effectiveness is not recognized by all newly emerged Caspian states.

In order to develop a Convention on the legal status of the Caspian Sea, in 1996, by decision of the foreign ministers of the five Caspian littoral states, a Special Working Group (SWG) was formed at the level of deputy foreign ministers.

Negotiations on the development of a Convention on the Legal Status of the Caspian Sea are being held within the framework of the AWG, as well as at bilateral and trilateral consultations. The agenda of the meetings also includes issues of interaction in the development of biological and mineral resources, navigation, ensuring security and preserving the Caspian ecosystem.

Coordination of draft sectoral international agreements on the Caspian theme is carried out at the level of representatives of the relevant government bodies of the parties.

On July 6, 1998, the Agreement on delimitation of the bottom of the northern part of the Caspian Sea for the purpose of exercising sovereign rights to subsoil use and on May 13, 2002, the Protocol to this Agreement were concluded between the Russian Federation and the Republic of Kazakhstan.

On November 29, 2001 and February 27, 2003, an Agreement was concluded between the Republic of Kazakhstan and the Republic of Azerbaijan on the delimitation of the bottom of the Caspian Sea and the Protocol thereto, respectively.

Caspian Sea - the largest lake on Earth, endorheic, located at the junction of Europe and Asia, called a sea because of its size, as well as because its bed is composed of oceanic-type crust. The water in the Caspian Sea is salty, from 0.05 ‰ near the mouth of the Volga to 11-13 ‰ in the southeast. The water level is subject to fluctuations, according to 2009 data it was 27.16 m below sea level. The area of the Caspian Sea is currently approximately 371,000 km², the maximum depth is 1025 m.

Geographical position

The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The length of the Caspian Sea from north to south is approximately 1200 kilometers (36°34"-47°13" N), from west to east - from 195 to 435 kilometers, on average 310-320 kilometers (46°-56° v. d.). The Caspian Sea is conventionally divided according to physical and geographical conditions into 3 parts - the Northern Caspian, the Middle Caspian and the Southern Caspian. The conditional border between the Northern and Middle Caspian runs along the line of the island. Chechen - Cape Tyub-Karagansky, between the Middle and Southern Caspian Sea - along the line of the island. Residential - Cape Gan-Gulu. The area of the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

The length of the coastline of the Caspian Sea is estimated at approximately 6500-6700 kilometers, with islands - up to 7000 kilometers. The shores of the Caspian Sea in most of its territory are low-lying and smooth. In the northern part, the coastline is indented by water channels and islands of the Volga and Ural deltas, the banks are low and swampy, and the water surface in many places is covered with thickets. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of the Absheron Peninsula and on the eastern coast in the area of the Kazakh Gulf and Kara-Bogaz-Gol. The territory adjacent to the Caspian Sea is called the Caspian region.

Peninsulas of the Caspian Sea

Large peninsulas of the Caspian Sea:

Agrakhan Peninsula
The Absheron Peninsula, located on the western coast of the Caspian Sea on the territory of Azerbaijan, at the northeastern end of the Greater Caucasus, on its territory the cities of Baku and Sumgait are located
Buzachi
Mangyshlak, located on the eastern coast of the Caspian Sea, on the territory of Kazakhstan, on its territory is the city of Aktau
Miankale
Tyub-Karagan

Islands of the Caspian Sea

There are about 50 large and medium-sized islands in the Caspian Sea with a total area of approximately 350 square kilometers. Largest islands:

Ashur-Ada
Garasu
Boyuk-Zira
Zyanbil
Cure Dashi
Khara-Zira
Ogurchinsky
Sengi-Mugan
Seal
Seal Islands
Chechen
Chygyl

Bays of the Caspian Sea

Large bays of the Caspian Sea:

Agrakhan Bay
Kizlyar Bay
Dead Kultuk (formerly Komsomolets, formerly Tsesarevich Bay)
Kaydak
Mangyshlaksky
Kazakh
Kenderli
Turkmenbashi (bay) (formerly Krasnovodsk)
Turkmen (bay)
Gizilagach (formerly Kirov Bay)
Astrakhan (bay)
Hasan-kuli
Gizlar
Hyrcanus (formerly Astarabad)
Anzali (formerly Pahlavi)
Kara-Bogaz-Gol

Rivers flowing into the Caspian Sea-130 rivers flow into the Caspian Sea, of which 9 rivers have a delta-shaped mouth. Large rivers flowing into the Caspian Sea are the Volga, Terek, Sulak, Samur (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Atrek (Turkmenistan), Sefidrud (Iran) and others. The largest river flowing into the Caspian Sea is the Volga, its average annual flow is 215-224 cubic kilometers. The Volga, Ural, Terek, Sulak and Emba provide up to 88-90% of the annual flow into the Caspian Sea.

Physiography

Area, depth, volume of water- the area and volume of water in the Caspian Sea varies significantly depending on fluctuations in water level. At a water level of −26.75 m, the area is approximately 371,000 square kilometers, the volume of water is 78,648 cubic kilometers, which is approximately 44% of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface level. In terms of maximum depth, the Caspian Sea is second only to Baikal (1620 m) and Tanganyika (1435 m). The average depth of the Caspian Sea, calculated from the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

Water level fluctuations- the water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past three thousand years, the magnitude of the change in the water level of the Caspian Sea has reached 15 meters. According to archeology and written sources, a high level of the Caspian Sea is recorded at the beginning of the 14th century. Instrumental measurements of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during which time the highest water level was recorded in 1882 (−25.2 m), the lowest in 1977 (−29.0 m), with Since 1978, the water level has risen and in 1995 reached −26.7 m; since 1996, a downward trend has emerged again. Scientists associate the reasons for changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors. But in 2001, sea level began to rise again, and reached −26.3 m.

Water temperature- water temperature is subject to significant latitudinal changes, most clearly expressed in winter, when the temperature varies from 0-0.5 °C at the ice edge in the north of the sea to 10-11 °C in the south, that is, the water temperature difference is about 10 ° C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25-26 °C. On average, the water temperature off the west coast is 1-2 °C higher than that on the east, and in the open sea the water temperature is 2-4 °C higher than off the coasts.

Water composition- the salt composition of the waters of the closed Caspian Sea differs from the oceanic one. There are significant differences in the ratios of concentrations of salt-forming ions, especially for waters in areas directly influenced by continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total amount of salts of sea waters, an increase in the relative amount of carbonates, sulfates, calcium, which are the main components in the chemical composition of river waters. The most conservative ions are potassium, sodium, chlorine and magnesium. The least conservative are calcium and bicarbonate ions. In the Caspian Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of Azov, and the sulfate anion is three times higher.

Bottom relief- the relief of the northern part of the Caspian Sea is a shallow undulating plain with banks and accumulative islands, the average depth of the Northern Caspian Sea is 4-8 meters, the maximum does not exceed 25 meters. The Mangyshlak threshold separates the Northern Caspian from the Middle Caspian. The Middle Caspian is quite deep, the water depth in the Derbent depression reaches 788 meters. The Absheron threshold separates the Middle and Southern Caspian Seas. The Southern Caspian is considered deep-sea; the water depth in the South Caspian depression reaches 1025 meters from the surface of the Caspian Sea. Shell sands are widespread on the Caspian shelf, deep-sea areas are covered with silty sediments, and in some areas there is an outcrop of bedrock.

Climate- the climate of the Caspian Sea is continental in the northern part, temperate in the middle part and subtropical in the southern part. In winter, the average monthly air temperature varies from −8…−10 in the northern part to +8…+10 in the southern part, in summer - from +24…+25 in the northern part to +26…+27 in the southern part. The maximum temperature of +44 degrees was recorded on the east coast. The average annual precipitation is 200 millimeters, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters along the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea is about 1000 millimeters per year, the most intense evaporation in the area of the Absheron Peninsula and in the eastern part of the South Caspian Sea is up to 1400 millimeters per year. The average annual wind speed is 3-7 meters per second, with northern winds prevailing in the wind rose. In the autumn and winter months, winds become stronger, with wind speeds often reaching 35-40 meters per second. The most windy areas are the Absheron Peninsula, the environs of Makhachkala and Derbent, where the highest wave of 11 meters was recorded.

Currents- water circulation in the Caspian Sea is associated with drainage and winds. Since most of the drainage occurs in the Northern Caspian Sea, northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current divides into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.

Economic development of the Caspian Sea

Mining of oil and gas-Many oil and gas fields are being developed in the Caspian Sea. Proven oil resources in the Caspian Sea are about 10 billion tons, total oil and gas condensate resources are estimated at 18-20 billion tons. Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf near Baku. In the second half of the 19th century, oil production began on an industrial scale on the Absheron Peninsula, and then in other territories. In 1949, oil was first produced at Neftyanye Kamni from the bottom of the Caspian Sea. So, on August 24 of this year, Mikhail Kaverochkin’s team began drilling a well, which yielded the long-awaited oil on November 7 of the same year. In addition to oil and gas production, salt, limestone, stone, sand, and clay are also mined on the coast of the Caspian Sea and the Caspian shelf.

Shipping- Shipping is developed in the Caspian Sea. There are ferry crossings on the Caspian Sea, in particular, Baku - Turkmenbashi, Baku - Aktau, Makhachkala - Aktau. The Caspian Sea has a shipping connection with the Sea of Azov through the Volga, Don and Volga-Don Canal rivers.

Fishing and seafood production-fishing (sturgeon, bream, carp, pike perch, sprat), caviar production, as well as seal fishing. More than 90 percent of the world's sturgeon catch occurs in the Caspian Sea. In addition to industrial mining, illegal fishing of sturgeon and their caviar flourishes in the Caspian Sea.

Legal status of the Caspian Sea- after the collapse of the USSR, the division of the Caspian Sea for a long time was and still remains the subject of unresolved disagreements related to the division of the resources of the Caspian shelf - oil and gas, as well as biological resources. For a long time, negotiations were ongoing between the Caspian states on the status of the Caspian Sea - Azerbaijan, Kazakhstan and Turkmenistan insisted on dividing the Caspian along the median line, Iran insisted on dividing the Caspian by one-fifth between all Caspian states. The current legal regime of the Caspian was established by the Soviet-Iranian treaties of 1921 and 1940 These treaties provide for freedom of navigation throughout the sea, freedom of fishing with the exception of ten-mile national fishing zones and a ban on vessels flying the flag of non-Caspian states sailing in its waters. Negotiations on the legal status of the Caspian Sea are currently ongoing.

Caspian Sea- the largest lake on Earth, located at the junction of Europe and Asia, called the sea because of its size. Caspian Sea is a closed lake, and the water in it is salty, from 0.05% near the mouth of the Volga to 11-13% in the southeast.
The water level is subject to fluctuations, currently approximately 28 m below the level of the World Ocean.
Square Caspian Sea currently - approximately 371,000 km2, maximum depth - 1025 m.

Length of coastline Caspian Sea is estimated at approximately 6,500 - 6,700 kilometers, with islands - up to 7,000 kilometers. Shores Caspian Sea Most of its territory is low-lying and smooth. In the northern part, the coastline is indented by water channels and islands of the Volga and Ural deltas, the banks are low and swampy, and the water surface in many places is covered with thickets. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of the Absheron Peninsula and on the eastern coast in the area of the Kazakh Gulf and Kara-Bogaz-Gol.

IN Caspian Sea 130 rivers flow in, of which 9 rivers have a delta-shaped mouth. Large rivers flowing into the Caspian Sea are the Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (Russian border with Azerbaijan), Atrek (Turkmenistan) and others.

Map of the Caspian Sea

The Caspian Sea washes the shores of five coastal states:

Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, coastline length 695 kilometers
Kazakhstan - in the north, northeast and east, the length of the coastline is 2320 kilometers
Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers
Iran - in the south, coastline length - 724 kilometers
Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

Water temperature

is subject to significant latitudinal changes, most clearly expressed in winter, when the temperature varies from 0 - 0.5 °C at the ice edge in the north of the sea to 10 - 11 °C in the south, that is, the difference in water temperature is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average, the water temperature off the west coast is 1 - 2 °C higher than that on the east, and in the open sea the water temperature is 2 - 4 °C higher than on the coasts.

Climate of the Caspian Sea- continental in the northern part, temperate in the middle part and subtropical in the southern part. In winter, the average monthly temperature of the Caspian Sea varies from?8?10 in the northern part to +8 - +10 in the southern part, in summer - from +24 - +25 in the northern part to +26 - +27 in the southern part. The maximum temperature recorded on the east coast was 44 degrees.

Animal world

The fauna of the Caspian Sea is represented by 1809 species, of which 415 are vertebrates. IN Caspian Sea 101 species of fish are registered, and it contains the majority of the world's sturgeon reserves, as well as freshwater fish such as roach, carp, and pike perch. Caspian Sea- habitat for fish such as carp, mullet, sprat, kutum, bream, salmon, perch, pike. IN Caspian Sea also inhabited by a marine mammal - the Caspian seal.

Vegetable world

Vegetable world Caspian Sea and its coastline is represented by 728 species. From plants to Caspian Sea The predominant algae are blue-green, diatoms, red, brown, characeae and others, and flowering algae include zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought in Caspian Sea by a person knowingly or on the bottoms of ships.

Mining of oil and gas

IN Caspian Sea Many oil and gas fields are being developed. Proven oil resources in Caspian Sea are about 10 billion tons, the total resources of oil and gas condensate are estimated at 18 - 20 billion tons.

Oil production in Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf. In the second half of the 19th century, oil production began on an industrial scale on the Absheron Peninsula, and then in other territories.

In addition to oil and gas production, on the coast Caspian Sea Salt, limestone, stone, sand, and clay are also mined on the Caspian shelf.

Ecological problems

Ecological problems Caspian Sea associated with water pollution as a result of oil production and transportation on the continental shelf, the flow of pollutants from the Volga and other rivers flowing into Caspian Sea, the life activity of coastal cities, as well as the flooding of individual objects due to rising levels Caspian Sea. Predatory production of sturgeon and their caviar, rampant poaching lead to a decrease in the number of sturgeon and to forced restrictions on their production and export.