Caspandmaboutre(Caspian) - the largest enclosed body of water on Earth. In size, the Caspian Sea is much larger than such lakes as the Upper, Victoria, Huron, Michigan, Baikal. According to formal features, the Caspian Sea is an endorheic lake. However, given its large size, brackish waters and sea-like regime, this body of water is called the sea.
According to one of the hypotheses, the Caspian Sea (among the ancient Slavs - the Khvalyn Sea) got its name in honor of the Caspian tribes who lived before our era on its southwestern coast.
The Caspian Sea washes the shores of five states: Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan.
The Caspian Sea is elongated in the meridional direction and is located between 36°33' and 47°07' N latitude. and 45°43΄ and 54°03΄ E (without Kara-Bogaz-Gol Bay). The length of the sea along the meridian is about 1200 km; the average width is 310 km. The northern coast of the Caspian Sea is bordered by the Caspian lowland, the eastern coast by the deserts of Central Asia; in the west, the mountains of the Caucasus approach the sea, in the south, near the coast, the Elburz ridge stretches.
The surface of the Caspian Sea is much lower than the level of the World Ocean. Its current level fluctuates around -27 ... -28 m. These levels correspond to the sea surface area of 390 and 380 thousand km 2 (without the Kara-Bogaz-Gol Bay), the volume of water is 74.15 and 73.75 thousand km 3, average depth is about 190 m.
The Caspian Sea is traditionally divided into three large parts: the North (24% of the sea area), the Middle (36%) and the South Caspian (40%), which differ significantly in morphology and regime, as well as the large and isolated Kara-Bogaz-Gol Bay. The northern, shelf part of the sea is shallow: its average depth is 5–6 m, maximum depths are 15–25 m, and the volume is less than 1% of the total water mass of the sea. The Middle Caspian is a separate basin with the area of maximum depths in the Derbent depression (788 m); its average depth is about 190 m. In the South Caspian, the average and maximum depths are 345 and 1025 m (in the South Caspian depression); 65% of the water mass of the sea is concentrated here.
There are about 50 islands in the Caspian Sea with a total area of approximately 400 km2; the main ones are Tyuleniy, Chechen, Zyudev, Konevsky, Dzhambaysky, Durneva, Ogurchinsky, Apsheronsky. The length of the coastline is approximately 6.8 thousand km, with islands - up to 7.5 thousand km. The shores of the Caspian Sea are diverse. In the northern and eastern parts, they are quite strongly indented. There are large bays Kizlyarsky, Komsomolets, Mangyshlaksky, Kazakhsky, Kara-Bogaz-Gol, Krasnovodsky and Turkmensky, many bays; off the western coast - Kyzylagach. The largest peninsulas are Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak, Krasnovodsky, Cheleken and Apsheronsky. The most common banks are accumulative; areas with abrasion shores are found along the contour of the Middle and South Caspian.
More than 130 rivers flow into the Caspian Sea, the largest of which is the Volga. , Ural, Terek, Sulak, Samur, Kura, Sefidrud, Atrek, Emba (its runoff enters the sea only in high-water years). Nine rivers have deltas; the largest are located at the mouths of the Volga and Terek.
The main feature of the Caspian Sea, as a drainless reservoir, is instability and a wide range of long-term fluctuations in its level. This most important hydrological feature of the Caspian Sea has a significant impact on all its other hydrological characteristics, as well as on the structure and regime of river mouths, on coastal zones. In the Caspian Sea level varied in the range of ~200 m: from -140 to +50 m BS; in from -34 to -20 m BS. From the first third of the 19th century and until 1977, sea level dropped by about 3.8 m - to the lowest point in the last 400 years (-29.01 m BS). In 1978–1995 The level of the Caspian Sea rose by 2.35 m and reached -26.66 m BS. Since 1995, a certain downward trend has dominated - to -27.69 m BS in 2013.
During major periods, the northern shore of the Caspian Sea shifted to Samarskaya Luka on the Volga, and perhaps even further. At maximum transgressions, the Caspian turned into a sewage lake: excess water flowed through the Kuma-Manych depression into the Sea of Azov and further into the Black Sea. In extreme regressions, the southern coast of the Caspian Sea was shifted to the Apsheron threshold.
Long-term fluctuations in the level of the Caspian are explained by changes in the structure of the water balance of the Caspian Sea. The sea level rises when the incoming part of the water balance (primarily river runoff) increases and exceeds the outgoing part, and decreases if the inflow of river waters decreases. The total water flow of all rivers averages 300 km 3 /year; while the five largest rivers account for almost 95% (the Volga provides 83%). During the period of the lowest sea level, in 1942–1977, the river flow was 275.3 km 3 / year (of which 234.6 km 3 / year is the flow of the Volga), precipitation - 70.9, underground flow - 4 km 3 /year, and evaporation and outflow to the Kara-Bogaz-Gol Bay - 354.79 and 9.8 km 3 /year. During the period of intensive sea level rise, in 1978-1995, respectively, 315 (Volga - 274.1), 86.1, 4, 348.79 and 8.7 km 3 / year; in the modern period - 287.4 (Volga - 248.2), 75.3, 4, 378.3 and 16.3 km 3 / year.
The intra-annual changes in the level of the Caspian Sea are characterized by a maximum in June–July and a minimum in February; the range of intra-annual level fluctuations is 30–40 cm. Surge-surge level fluctuations are manifested throughout the sea, but they are most significant in the northern part, where, with maximum surges, the level can rise by 2–4.5 m and the line “retreat” by several tens of kilometers inland, and in case of surges - to drop by 1–2.5 m. Seiche and tidal level fluctuations do not exceed 0.1–0.2 m.
Despite the relatively small size of the reservoir in the Caspian Sea, there is strong excitement. The highest wave heights in the South Caspian can reach 10–11 m. Wave heights decrease from south to north. Storm waves can develop at any time of the year, but more often and more dangerously in the cold half of the year.
The Caspian Sea is generally dominated by wind currents; nevertheless, runoff currents play an appreciable role on the estuarine coasts of large rivers. Cyclonic water circulation prevails in the Middle Caspian, and anticyclonic circulation in the South Caspian. In the northern part of the sea, the patterns of wind currents are more irregular and depend on the characteristics and variability of the wind, bottom topography and coastlines, river runoff and aquatic vegetation.
The water temperature is subject to significant latitudinal and seasonal changes. In winter, it varies from 0–0.5 o C at the ice edge in the north of the sea to 10–11 o C in the south. In summer, the water temperature in the sea averages 23–28 o C, and in shallow coastal waters in the Northern Caspian it can reach 35–40 o C. At depths, a constant temperature is maintained: deeper than 100 m it is 4–7 o C.
In winter, only the northern part of the Caspian Sea freezes; in severe winter - the entire Northern Caspian and the coastal zones of the Middle Caspian. Freezing in the Northern Caspian lasts from November to March.
The salinity of water changes especially sharply in the northern part of the sea: from 0.1‰ on the estuarine coasts of the Volga and Urals to 10–12‰ on the border with the Middle Caspian. In the Northern Caspian, the temporal variability of water salinity is also great. In the middle and southern parts of the sea, salinity fluctuations are small: it is mainly 12.5–13.5‰, increasing from north to south and from west to east. The highest water salinity is in the Kara-Bogaz-Gol Bay (up to 300‰). With depth, the salinity of water increases slightly (by 0.1–0.3‰). The average salinity of the sea is about 12.5‰.
More than a hundred species of fish live in the Caspian Sea and the mouths of the rivers flowing into it. There are Mediterranean and Arctic invaders. Gobies, herring, salmon, carp, mullet and sturgeon fish serve as the object of fishing. The latter number five species: sturgeon, beluga, stellate sturgeon, spike and sterlet. The sea is capable of producing up to 500-550 thousand tons of fish annually if overfishing is not allowed. Of the marine mammals, the endemic Caspian seal lives in the Caspian Sea. Every year 5-6 million waterfowl migrate through the Caspian region.
The economy of the Caspian Sea is connected with oil and gas production, shipping, fishing, extraction of seafood, various salts and minerals (Kara-Bogaz-Gol Bay), with the use of recreational resources. The explored oil resources in the Caspian Sea are about 10 billion tons, the total resources of oil and gas condensate are estimated at 18–20 billion tons. Oil and gas are being produced on an ever-increasing scale. The Caspian Sea is also used by water transport, including along the river-sea and sea-river routes. The main ports of the Caspian Sea: Astrakhan, Olya, Makhachkala (Russia), Aktau, Atyrau (Kazakhstan), Baku (Azerbaijan), Nowshahr, Bender-Enzeli, Bender-Torkemen (Iran) and Turkmenbashi (Turkmenistan).
The economic activity and hydrological features of the Caspian Sea create a number of serious environmental and water management problems. Among them: anthropogenic pollution of river and sea waters (mainly with oil products, phenols and synthetic surfactants), poaching and reduction of fish stock, especially sturgeons; damage to the population and coastal economic activity due to large-scale and rapid changes in the level of the reservoir, the impact of numerous hazardous hydrological phenomena and hydrological and morphological processes.
The total economic damage for all the Caspian countries associated with the rapid and significant recent rise in the level of the Caspian Sea, the flooding of part of the coastal land, the destruction of coasts and coastal structures, was estimated at 15 to 30 billion US dollars. It took urgent engineering measures to protect the coast.
A sharp drop in the level of the Caspian Sea in the 1930s–1970s. led to less damage, but they were significant. The navigable approach channels became shallow, the shallow seashore at the mouths of the Volga and the Urals became heavily overgrown, which became an obstacle to the passage of fish into the rivers for spawning. It was necessary to build fish passages through the seasides mentioned above.
Among the unresolved problems is the lack of an international agreement on the international legal status of the Caspian Sea, the division of its water area, bottom and subsoil.
The Caspian Sea is the object of many years of research by specialists from all the Caspian states. Such domestic organizations as the State Oceanographic Institute, the Institute of Oceanology of the Russian Academy of Sciences, the Hydrometeorological Center of Russia, the Caspian Research Institute of Fisheries, the Faculty of Geography of Moscow State University, etc. took an active part in the study of the Caspian Sea.
Caspian Sea The Caspian Sea (Greek Káspion pélagos, Latin Caspium Mare), the world's largest enclosed body of water in the USSR (RSFSR, Kazakh SSR, Turkmen SSR, Azerbaijan SSR) and Iran. It is often regarded as the greatest lake on Earth, which is inaccurate, because in terms of its size, the nature of the processes, and the history of its development, the sea is a sea. It received its name from the ancient tribes of the Caspians (See Caspians), who lived in the eastern part of the Caucasus. Other historical names -
Hyrcanian, Khvalynsk (Khvalissk), Khazar - also by the names of the ancient peoples who lived on its shores. Physico-geographical essay. General information. K. m. elongated from north to south by almost 1200 km, average width 320 km, the length of the coastline is about 7 thousand km. km(Of which more than 6,000 km within the USSR). The area is about 371 thousand sq. km 2; level at 28.5 m below the level of the World Ocean (1969). Maximum depth 1025 m. In 1929, before a significant decrease in the level of the K. m., its area was 422 thousand square meters. km 2. The largest bays are: in the north - Kizlyarsky, Komsomolets; in the east - Mangyshlaksky, Kenderli, Kazakhsky, Kara-Bogaz-Gol, Krasnovodsky; in the west - Agrakhansky, Baku Bay; in the south - shallow lagoons. There are up to 50 islands, mostly small ones (the total area is about 350 km 2),
the most significant are Kulaly, Tyuleniy, Chechen, Artem, Zhiloy, Ogurchinsky. The most significant rivers flow into the northern part of the sea - the Volga, Emba, Ural, Terek, the total annual flow of which is about 88% of the total river water flow into the Caspian. On the western coast, the large rivers Sulak, Samur, Kura and a number of smaller ones (about 7% of the flow) flow into it. The remaining 5% of the runoff is provided by the rivers of the Iranian coast (Gorgan, Heraz, Sefidrud). On the east coast, including the coast of Kara-Bogaz-Gol, there is not a single permanent watercourse. Shores. The shores of the northern part of the Caspian are low-lying and very sloping, characterized by a wide development of droughts formed as a result of surge phenomena; deltaic shores are also developed here (deltas of the Volga, Ural, Terek). In general, the coasts of the northern part are intensively growing, which is facilitated by a drop in sea level, the rapid growth of deltas, and an abundant supply of terrigenous material. The western shores of the Caspian Sea are also mostly accumulative (numerous bay-bars and spits), and some areas on the coasts of Dagestan and the Absheron Peninsula are abrasion. On the eastern coast of the sea, abrasion shores, worked out in limestone, which form the adjacent semi-desert and desert plateaus, predominate. There are also accumulative forms: the Karabogaz bay separating from the sea the largest bay of the Caspian - Kara-Bogaz-Gol, the Krasnovodskaya and Kenderli spits. To the south of the Krasnovodsk Peninsula, accumulative shores predominate. Relief. According to the nature of the relief and hydrological features, the Caspian Sea is usually subdivided into the Northern Caspian, the Middle Caspian, and the Southern Caspian. Northern Caspian (area about 80 thousand sq. km 2) -
the shallowest part of the sea with depths 4-8 m.
The bottom relief is a slightly wavy accumulative plain with a series of banks and accumulative islands, the so-called Mangyshlak threshold, which separates the Northern Caspian from the Middle. Within the Middle Caspian (an area of about 138 thousand sq. km 2) stand out: Derbent depression (maximum depth 788 m),
shelf and continental slope, complicated by underwater landslides and canyons; on the northern, rather gentle slope, relics of ancient river valleys were found. In the south, the basin of the Middle Caspian is separated from the basin of the South Caspian by the Apsheron threshold, on which a number of banks and islands are located. The basin of the South Caspian (the greatest depth is 1025 m), which is about 1/3 of the area of the sea, has a narrow shelf off the western and southern (Iranian) coasts, and the shelf is much wider off the eastern coast. The bottom of the depression is a flat abyssal plain. In the northern part of the basin, there are several underwater ridges with northwestern and southeastern strikes. Geological structure and minerals. The northern part of the Caspian sea is the margin of the Caspian syneclise of the East European platform; The Mangyshlak threshold is structurally connected with the Hercynian buried shaft of Karpinsky on the western coast of the sea and with the mountains of Mangyshlak on the east. The bottom of the Middle Caspian has a heterogeneous structure. Its eastern part is a submerged section of the epihercynian Turan platform; The Derbent depression, as well as the western parts of the shelf and the continental slope, are the marginal foredeep of the Greater Caucasus geosyncline. The Apsheron Sill corresponds to one of the branches of the newest structures formed on the subsidence of the folded formations of the Greater Caucasus and connecting them with the folded structures of the Kopetdag. The Southern Caspian is characterized by the suboceanic structure of the earth's crust; there is no granite layer here. Under the sedimentary layer up to 25 km(which obviously indicates the great antiquity of the South Caspian depression) there is a basalt layer up to 15 km.
Up to the Upper Miocene, the Caspian as a marine basin in its geological history was closely connected with the Black Sea. After the Upper Miocene folding, this connection was interrupted, and the K. m. turned into a closed reservoir. Communication with the ocean resumed in the Upper Pliocene, in the Akchagyl age. In the Anthropogen, in connection with the alternation of glacial and postglacial epochs on the East European Plain, the Caspian Sea repeatedly experienced transgressions (Baku, Khazar, Khvalyn) and regressions, traces of which are preserved in the form of terraces on the sea coast and in the stratigraphy of the ancient Caspian deposits. On the shelf, terrigenous-shell sands, shells, and oolitic sands are common; deep-water areas of the bottom are covered with silty and silty sediments with a high content of calcium carbonate. In some areas of the bottom, Neogene bedrocks are exposed. At the bottom of the sea there are rich deposits of oil and gas. Oil and gas are the Apsheron threshold, the Dagestan and Turkmen regions of the sea. Promising for oil and gas are the areas of the seabed adjacent to Mangyshlak, as well as the Mangyshlak threshold. The Kara-Bogaz-Gol Bay is the largest deposit of chemical raw materials (in particular, mirabilite). Climate. The main baric centers that determine atmospheric circulation in the area of the Caspian Sea are the spur of the Asian maximum in winter and the spurs of the Azores maximum and South Asian minimum in summer. Characteristic features of the climate are: significant continentality, the predominance of anticyclonic weather conditions, dry winds, severe frosty winters (especially in the northern part), sharp temperature changes throughout the year, poverty in precipitation (excluding the southwestern part of the reservoir). At atmospheric fronts, cyclonic activity is developing, which is also an important element of climate and weather in the Caspian. In the northern and middle parts of the Caspian Sea, easterly winds prevail from October to April, and northwestern winds prevail from May to September; in the southern part of the sea, the monsoon character of the winds is most pronounced. The strongest winds are found in the area of the Absheron Peninsula (Baku north blowing mainly in autumn), the eastern coast of the middle part and the northwestern region of the northern part; storms are frequent here, in which the wind speed reaches more than 24 m/sec.
The average long-term air temperature of the warm months (July-August) over the entire sea is 24-26 °C, the absolute maximum (up to 44 °C) is noted on the east coast. In the winter months, the temperature varies from -10 °C in the north to 12 °C in the south. An average of 200 mm precipitation per year, on the west coast - up to 400 mm,
in the arid east - 90-100 mm,
in the subtropical southwestern part of the coast - before 1700 mm. Evaporation from most of the sea surface is very high - up to 1000 mm in year; in the eastern part of the South Caspian and in the area of the Apsheron Peninsula - up to 1400 mm in year. hydrological regime. The cyclonic circulation of waters dominates in the sea, mainly due to river runoff and prevailing winds. Masses of water move from north to south along the western coast of the sea to the Absheron Peninsula, where the current divides: one branch continues along the western coast, the other crosses the Caspian Sea in the region of the Apsheron threshold and, near the eastern coast, joins with waters moving to the north. along the eastern shore from the South Caspian. In the South Caspian, cyclonic circulation is also observed, but less clearly expressed, and between Baku and the mouth of the river. Chickens complicated by local anticyclone circulation. Unstable wind currents of various directions prevail in the Northern Caspian. Their speed is usually 10-15 cm/sec, with strong winds coinciding with the direction of the currents, the speed can reach 30-40 and even 100 cm/sec. The frequent recurrence of moderate and strong winds causes a large number of days with significant waves. Maximum observed wave height up to 11 m- in the area of the Apsheron threshold. The water temperature in summer on the surface averages 24-26°C, in the south - up to 29°C, in the Krasnovodsk Bay - up to 32°C. Near the eastern shores in July and August the temperature sometimes drops to 10-12 °C. This phenomenon is associated with the driving effect of winds and the rise of deep waters. In winter, there are significant temperature contrasts: negative temperatures (up to -0.5°C) in the north, 3–7°C in the Middle Caspian, and 8–10°C in the South. The northern part of the sea usually freezes for 2-3 months., the ice thickness reaches 2 m. In the Middle Caspian, in severe winters, individual shallow bays freeze. There are frequent cases of intense breaking of ice by the wind and their drift from the North Caspian to the south along the western coast. In some years, floating ice reaches the area of the Apsheron Peninsula and can cause significant damage to hydraulic structures in the sea. The average salinity of the waters is 12.7-12.8 ‰, the maximum (not counting the Kara-Bogaz-Gol Bay) near the eastern shores is up to 13.2 ‰, the minimum is in the northwest. - 1-2 ‰. Fluctuations in salinity over the area of the sea, along the vertical, and over time are insignificant, and only in the north are they more noticeable in connection with fluctuations in the flow of the Volga. The composition of salts differs from the usual oceanic salts in a high content of sulfates, calcium and magnesium carbonates and, accordingly, a lower content of chlorides, which is due to the influence of river runoff. Vertical mixing of waters in winter covers the entire water column in the Northern Caspian and layer 200-300 m in deep-water areas, in summer and autumn it is limited to the upper layer 15-30 m. In these seasons, at the lower boundary of the upper well-heated and mixed layer (15-30 m) an intense layer of temperature jump (several degrees per meter) is formed, which prevents the spread of heat into the deep layers of the sea. Level fluctuations. Short-term non-periodic fluctuations in the level of K. m. m or downgrade to 2 m. Seishi are observed with a period of 10 min to 12 h with amplitude up to 0.7 m. There are small seasonal fluctuations in the level (about 30 cm). The level of K. m. is subject to significant long-term and secular fluctuations, determined mainly by changes in its water balance. According to geological, archaeological, historical and geomorphological data, it has been established that a high level of K. m. (up to a mark of 22 m) was noted 4-6 thousand years ago, at the beginning of AD. e. and at the beginning of the 19th century. (New Caspian transgression). It is also known that in the 7-11 centuries. n. e. was low (perhaps 2-4 m below modern). The last major decline in the level occurred since 1929 (when the level was around 26 m) until 1956-57. Now the level fluctuates within several cm around 28.5 m. In addition to climatic changes, which led to a decrease in river runoff in the Caspian Sea and an increase in evaporation from its surface, the reasons for the last drop in the level were also hydraulic engineering construction on the Volga (creation of large artificial reservoirs) and the consumption of river waters for irrigating arid lands and for production needs. The runoff of the K. m. in the Kara-Bogaz-Gol Bay also negatively affects the water balance, the level of which is 4 m below the level of the Caspian Sea. In general, the components of the water balance for 1970: income - precipitation 66.8 km 3, river flow 266.4 km 3, underground inflow 5 km 3, consumption - evaporation 357.3 km 3, drain to Kara-Bogaz-Gol 4 km 3 , sea water intake 1 km 3 . The excess of the expenditure over the inflow of water causes an average annual decrease in the level (for the period 1966-67) by 7 cm. To prevent a further drop in sea level (by 2000, a level decrease of 2 m) a number of measures are being developed. There is a project to transfer the flow of the northern rivers - Vychegda and Pechora - in the Volga basin, which will give the Volga and K. m. about 32 km 3 water per year; a project was developed (1972) to regulate the flow of Caspian waters into the Kara-Bogaz-Gol Bay. The flora and fauna of the K. m. are rather poor in species composition, but significant in biomass. More than 500 species of plants and 854 species of fish and animals, diverse in their origin, live in the Caspian Sea. Blue-green and diatom (rhizosolinae, etc.) algae predominate among the plants in the sea. Among recent invaders there are many red and brown algae. Of the flowering plants, zostera and ruppia are the most common. Chara algae provide the largest biomass (up to 30 kg for 1 m 3 bottoms). By origin, the fauna is mainly of the Neogene age, which has experienced great changes due to frequent and significant fluctuations in salinity. This group includes fish - sturgeons, herring, sprats, gobies, gobies, from mollusks - zebra mussels and cockles, from other invertebrates - gammarids, polychaetes, sponges, one type of jellyfish. In addition, 15 species of invaders from the Arctic and Mediterranean basins live here. A noticeable group is represented by organisms of freshwater origin (from fish - pike perch). In general, a high degree of endemism is characteristic. Some organisms have migrated to the sea just recently either as a result of introduction on the bottoms of sea vessels (mainly various fouling agents, such as mytilaster, rhizosalium algae, balanuses, and crabs) or through conscious acclimatization by humans (for example, from fish - mullet, from invertebrates - nereis, syndesmia). Research History. Documentary evidence of the acquaintance of Russians with the K. m. and their voyages on it dates back to the 9th-10th centuries. (Arabic, Armenian, Iranian ancient manuscripts). Regular exploration of the Caspian Sea was begun by Peter I, on whose initiative an expedition was organized in 1714-15 under the leadership of A. Bekovich-Cherkassky, who explored, in particular, the eastern coast of the Caspian Sea. In the 20s. 18th century hydrographic studies of the sea were started by I.F. Soymonov; in the second half of the 18th century. they were continued by I. V. Tokmachev, M. I. Voinovich, at the beginning of the 19th century. - Kolodkin, who for the first time performed instrumental compass survey of the coast. In the middle of the 19th century a detailed instrumental hydrographic survey of the rock was carried out under the direction of N. A. Ivashintsev. The maps created as a result of these surveys served as the basis for subsequent editions of nautical charts for the Caspian until the 1930s. 20th century In the study of natural conditions K. m. in the 19th century. scientists made a great contribution - P. S. Pallas, S. G. Gmelin, G. S. Karelin, K. M. Baer, G. V. Abikh, O. A. Grim, N. I. Andrusov, I. B. . Spindler. In 1897 the Astrakhan Research Station (now the Caspian Institute of Fisheries) was founded. 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. These works were continued after 1917 by the Caspian Expedition created under the Academy of Sciences of the USSR, also led by Knipovich. In the first decades after the October Revolution, an outstanding role in the study of the geological structure and oil content of the Apsheron Peninsula and the geological history of the K. m. was played by the research of owls. geologists I. M. Gubkin, D. V. and V. D. Golubyatnikov, P. A. Pravoslavlev, V. P. Baturin, S. A. Kovalevsky. B. A. Appolov, V. V. Valedinsky, K. P. Voskresensky, and L. S. Berg made a significant contribution to the study of the water balance and fluctuations in the level of the sea level at that time. After the Great Patriotic War of 1941–45, systematic, versatile research began on the sea, aimed at studying the hydrometeorological regime, the biological conditions, and the geological structure of the sea (Moscow State University, the Institute of Geography of the Academy of Sciences of the Azerbaijan SSR, the State Oceanographic Institute, and the observatory of the hydrometeorological service. institutes of geology and development of fossil fuels (IGIRGI) and physics of the Earth of the Academy of Sciences of the USSR, the Laboratory of Aeromethods and the All-Russian Research Institute of Geophysics of the Ministry of Geology of the USSR, the Caspian Institute of Sturgeon Fisheries and other scientific institutions of the Republican Academy of Sciences and ministries]. Economic and geographical outline. The Caspian Sea has long been famous as an area for the production of valuable varieties of fish, especially sturgeon (82% of the world catch), herring, and freshwater fish (bream, pike perch, roach, and carp). As a result of the fall in sea level (which resulted in the disappearance of valuable spawning grounds), the regulation of the flow of the Volga, Kura and Araks rivers, which worsened the breeding conditions for anadromous and semi-anadromous fish, etc. the number and catch of primarily valuable varieties of fish (herring, sturgeon) have declined sharply. In 1936, the gross catch of fish was about 500,000 tonnes. t, in 1956 - 461 thousand. t(respectively, the catch of sturgeon - 21.5 and 15.0, roach - 197 and 18, pike perch - 55 and 8.4 thousand tons). t). A relatively small reduction in the gross catch is due to a sharp increase in the production of low-value fish, mainly kilka. In connection with the decrease in the number of sturgeons, work is underway to breed and restore valuable fish species. In 1924, oil production began for the first time in Ilyich Bay (Baku region), but production increased especially after the Great Patriotic War of 1941-45. Oil is extracted in the sea from overpasses (Oil Rocks) and artificial islands. The main regions are Priapsheronsky, Sangachalsky near the western coast, Chelekensky - near the east. Offshore oil fields provide more than 50% of all oil produced in the Azerbaijan SSR. Of great economic importance is the extraction of sodium sulfate, mirabilite and epsomite in the Kara-Bogaz-Gol region. The ever-increasing need for fresh water has led to the appearance of seawater desalination plants in the sea. the largest of them (to obtain fresh water for industrial and domestic needs in the adjacent desert and semi-desert regions) are being built (1972) in the cities. Shevchenko and Krasnovodsk. The metropolitan area is of great transport importance both for internal transportation and for external communications. The main cargoes transported across the Caspian are oil, timber, grain, cotton, rice, sulfate. The largest ports - Astrakhan, Baku, Makhachkala, Krasnovodsk, Shevchenko - are also connected by regular flights of passenger ships. Sea railways run between Baku and Krasnovodsk. ferries. A ferry service between Makhachkala and Shevchenko is being designed (1972). In Iran, the main ports are Pahlavi and Bandar Shah. Lit.: Fluctuations in the level of the Caspian Sea, M., 1956; Fedorov P.V., Stratigraphy of Quaternary deposits and the history of the development of the Caspian Sea, M., 1957; Geological structure of the underwater slope of the Caspian Sea, M., 1962; Materials of the All-Union Conference on the Problem of the Caspian Sea, Baku, 1963; Zenkevich L. A., Biology of the Seas of the USSR, M., 1963; Leontiev O. K., Khalilov A. I., Natural conditions for the formation of the shores of the Caspian Sea, Baku, 1965; Pakhomova A. S., Zatuchnaya B. M., Hydrochemistry of the Caspian Sea, Leningrad, 1966; Geology of oil and gas fields of Azerbaijan, M., 1966; Caspian Sea, M., 1969; Complex studies of the Caspian Sea. Sat. st., c. 1, M., 1970; Gul K. K., Lappalainen T. N., Polushkin V. A., Caspian Sea, Moscow, 1970; Gul K. K., Zhilo P. V., Zhirnov V. M., Bibliographic annotated guide to the Caspian Sea. Baku, 1970. K. K. Gul, O. K. Leontiev.
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
Synonyms:See what the "Caspian Sea" is in other dictionaries:
Drainage, washes the shores of Russia (Dagestan, Kalmykia, Astrakhan region) and Azerbaijan, Iran, Kazakhstan, Turkmenistan. The earliest mention of the Caspian Sea is found in Assyrian. cuneiform inscriptions (VIII VII centuries BC), where it ... ... Geographic Encyclopedia
CASPIAN SEA, the world's largest endorheic lake. The area is 376 thousand km2. Lies 27.9 m below sea level (1986). From 1929 to 1977 there was a drop in the level, from 1978 a rise began. In the North Caspian the depth is 5-8 m, in the Middle Caspian up to 788 m... Modern Encyclopedia
The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The Caspian Sea is similar in shape to the Latin letter S, 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° E).
The Caspian Sea is conditionally 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 North and the Middle Caspian we pass along the Chechen line (island)- Tyub-Karagansky Cape, between the Middle and South Caspian - along the line of the Residential (island)- Gan Gulu (cape). The area of the Northern, Middle and Southern Caspian is 25, 36, 39 percent respectively.
According to one of the hypotheses, the Caspian Sea got its name in honor of the ancient tribes of horse breeders - the Caspians, who lived before our era on the southwestern coast of the Caspian Sea. Throughout the history of its existence, the Caspian Sea had about 70 names for different tribes and peoples: the Hyrcanian Sea; The Khvalyn Sea or the Khvalis Sea is an ancient Russian name, derived from the name of the inhabitants of Khorezm, who traded in the Caspian Sea - Khvalis; Khazar Sea - name in Arabic (Bahr-al-Khazar), Persian (Daria-e Khazar), Turkish and Azerbaijani (Khazar Denizi) languages; Abeskun Sea; Saray Sea; Derbent Sea; Sihai and other names. In Iran, the Caspian Sea is still called the Khazar or Mazenderan (by the name of the people inhabiting the coastal province of Iran of the same name).
The coastline of the Caspian Sea is estimated at about 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 streams and islands of the Volga and Ural deltas, the shores are low and swampy, and the water surface is covered with thickets in many places. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding coasts are on the west coast in the area of the Apsheron Peninsula and on the east coast in the area of the Kazakh Gulf and Kara-Bogaz-Gol.
Large peninsulas of the Caspian Sea: Agrakhan Peninsula, Absheron Peninsula, Buzachi, Mangyshlak, Miankale, Tub-Karagan.
There are about 50 large and medium-sized islands in the Caspian Sea with a total area of approximately 350 square kilometers. The largest islands: Ashur-Ada, Garasu, Gum, Dash, Zira (island), Zyanbil, Kyur Dashy, Khara-Zira, Sengi-Mugan, Chechnya (island), Chygyl.
Large bays of the Caspian Sea: Agrakhansky Bay, Komsomolets (bay) (former Dead Kultuk, former Tsesarevich Bay), Kaydak, Mangyshlak, Kazakh (bay), Turkmenbashi (bay) (former Krasnovodsk), Turkmen (bay), Gyzylagach, Astrakhan (bay), Gyzlar, Girkan (former Astarabad) and Anzeli (former Pahlavi).
Off the eastern coast is the salt lake Kara Bogaz Gol, which until 1980 was a bay-lagoon of the Caspian Sea, connected to it by a narrow strait. In 1980, a dam was built separating Kara-Bogaz-Gol from the Caspian Sea, in 1984 a culvert was built, after which the level of Kara-Bogaz-Gol dropped by several meters. In 1992, the strait was restored, through which water leaves the Caspian Sea to Kara-Bogaz-Gol and evaporates there. Every year, 8-10 cubic kilometers of water enters Kara-Bogaz-Gol from the Caspian Sea (according to other sources - 25 thousand kilometers) and about 150 thousand tons of salt.
130 rivers flow into the Caspian Sea, of which 9 rivers have a mouth in the form of a delta. Large rivers flowing into the Caspian Sea - Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (border of Russia with Azerbaijan), Atrek (Turkmenistan) and others. The largest river flowing into the Caspian Sea is the Volga, its average annual runoff is 215-224 cubic kilometers. The Volga, Ural, Terek and Emba provide up to 88 - 90% of the annual drainage of the Caspian Sea.
The area of the Caspian Sea basin is approximately 3.1 - 3.5 million square kilometers, which is approximately 10 percent of the world's closed water basins. The length of the Caspian Sea basin from north to south is about 2,500 kilometers, from west to east - about 1,000 kilometers. The Caspian Sea basin covers 9 states - Azerbaijan, Armenia, Georgia, Iran, Kazakhstan, Russia, Uzbekistan, Turkey and Turkmenistan.
The Caspian Sea washes the shores of five coastal states:
- Russia (Dagestan, Kalmykia and Astrakhan region)- in the west and northwest, the length of the coastline is 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, the length of the coastline - 724 kilometers
- Azerbaijan - in the southwest, the length of the coastline is 955 kilometers
The largest city - a port on the Caspian Sea - Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and has 2,070 thousand people (2003) . Other large Azerbaijani Caspian cities are Sumgayit, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the South-East of the Absheron peninsula, there is the settlement of oil workers Neftyanye Kamni, whose facilities are located on artificial islands, overpasses and technological sites.
Large Russian cities - the capital of Dagestan Makhachkala and the southernmost city of Russia Derbent - are located on the western coast of the Caspian Sea. 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.
On the eastern shore of the Caspian Sea there is a Kazakh city - the port of Aktau, in the north in the Ural delta, 20 km from the sea, the city of Atyrau is located, south of Kara-Bogaz-Gol on the northern shore of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, formerly Krasnovodsk. Several Caspian cities are located in the southern (Iranian) coast, the largest of them - Anzeli.
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 was approximately 392,600 square kilometers, the volume of water was 78,648 cubic kilometers, which is approximately 44 percent 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.
The water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past 3 thousand years, the amplitude of changes in the water level of the Caspian Sea has amounted to 15 meters. Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during this time the highest water level was recorded in 1882 (-25.2 m.), the lowest - in 1977 (-29.0 m.), since 1978 the water level has risen and in 1995 reached -26.7 m, since 1996 there has been a downward trend again. Scientists associate the causes of changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.
The water temperature is subject to significant latitudinal changes, most pronounced in winter, when the temperature changes from 0 - 0.5 °C at the ice edge in the north of the sea to 10 - 11 °C in the south, i.e. 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 near the western coast is 1 - 2 °C higher than that of the eastern coast, and in the open sea the water temperature is 2 - 4 °C higher than near the coasts. According to the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time intervals can be distinguished in the upper 2-m layer. From October to March, the water temperature increases in the south and east, which is especially evident in the Middle Caspian. Two stable quasi-latitudinal zones can be distinguished, where the temperature gradients are elevated. This is, firstly, the border between the North and Middle Caspian, and, secondly, between the Middle and South. At the ice edge, in the northern frontal zone, the temperature in February-March increases from 0 to 5 °C, in the southern frontal zone, in the area of the Apsheron threshold, from 7 to 10 °C. During this period, the least chilled waters are in the center of the South Caspian, which form a quasi-stationary core. In April-May, the area of minimum temperatures moves to the Middle Caspian, which is associated with faster warming of waters in the shallow northern part of the sea. True, at the beginning of the season in the northern part of the sea, a large amount of heat is spent on melting ice, but already in May the temperature rises here to 16 - 17 °C. In the middle part, the temperature at this time is 13 - 15 °C, and in the south it rises to 17 - 18 °C. The spring warming of the water evens out the horizontal gradients, and the temperature difference between the coastal areas and the open sea does not exceed 0.5 °C. The heating of the surface layer, which begins in March, breaks the uniformity in the temperature distribution with depth. In June-September, there is a horizontal uniformity in the temperature distribution in the surface layer. In August, which is the month of the greatest warming, the water temperature throughout the sea is 24 - 26 °C, and in the southern regions it rises to 28 °C. In August, the water temperature in shallow bays, for example, in Krasnovodsk, can reach 32 °C. The main feature of the water temperature field at this time is upwelling. It is observed annually along the entire eastern coast of the Middle Caspian and partially penetrates even into the South Caspian. The rise of cold deep waters occurs with varying intensity as a result of the influence of northwestern winds prevailing in the summer season. The wind of this direction causes the outflow of warm surface waters from the coast and the rise of colder waters from the intermediate layers. Upwelling starts in June, but it reaches its highest intensity in July-August. As a result, there is a decrease in temperature on the surface of the water. (7 - 15°C). Horizontal temperature gradients reach 2.3 °C at the surface and 4.2 °C at a depth of 20 m. in June to 43 - 45 ° N in September. Summer upwelling is of great importance for the Caspian Sea, radically changing the dynamic processes in the deep water area. In the open areas of the sea in late May - early June, the formation of a temperature jump layer begins, which is most clearly expressed in August. Most often, it is located between the horizons of 20 and 30 m in the middle part of the sea and 30 and 40 m in the southern part. Vertical temperature gradients in the shock layer are very significant and can reach several degrees per meter. In the middle part of the sea, due to the surge near the eastern coast, the shock layer rises close to the surface. Since there is no stable baroclinic layer in the Caspian Sea with a large potential energy reserve similar to the main thermocline of the World Ocean, with the cessation of the effect of the prevailing winds that cause upwelling, and with the onset of autumn-winter convection in October-November, the temperature fields are rapidly reorganized to the winter regime. In the open sea, the water temperature in the surface layer drops in the middle part to 12 - 13 °C, in the southern part to 16 - 17 °C. In the vertical structure, the shock layer is washed out due to convective mixing and disappears by the end of November.
The salt composition of the waters of the closed Caspian Sea differs from that of the ocean. There are significant differences in the ratios of the concentrations of salt-forming ions, especially for the waters of areas under the direct influence of 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 in sea waters, an increase in the relative amount of carbonates, sulfates, and calcium, which are the main components in the chemical composition of river waters. The most conservative ions are potassium, sodium, chloride and magnesium. The least conservative are calcium and bicarbonate ion. In the Caspian Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of Azov, and sulfate anion is three times higher. The salinity of water changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and the Urals up to 10 - 11 units. psu on the border with the Middle Caspian. Mineralization in shallow saline bays-kultuks can reach 60 - 100 g/kg. In the Northern Caspian, during the entire ice-free period from April to November, a quasi-latitudinal salinity front is observed. The greatest desalination associated with the spread of river runoff over the sea area is observed in June. The formation of the salinity field in the Northern Caspian is greatly influenced by the wind field. In the middle and southern parts of the sea, salinity fluctuations are small. Basically, it is 11.2 - 12.8 units. psu, increasing in the southern and eastern directions. Salinity increases slightly with depth. (at 0.1 - 0.2 psu). In the deep-water part of the Caspian Sea, in the vertical salinity profile, characteristic isohaline troughs and local extrema are observed in the area of the eastern continental slope, which indicate the processes of near-bottom creep of waters becoming saline in the eastern shallow waters of the South Caspian. Salinity is also highly dependent on sea level and (which is related) from the amount of continental runoff.
The relief of the northern part of the Caspian is a shallow wavy plain with banks and accumulative islands, the average depth of the Northern Caspian is about 4 - 8 meters, the maximum does not exceed 25 meters. The Mangyshlak threshold separates the Northern Caspian from the Middle. The Middle Caspian is quite deep, the depth of water in the Derbent depression reaches 788 meters. The Apsheron threshold separates the Middle and South Caspian. The South Caspian is considered deep water, the depth of water in the South Caspian depression reaches 1025 meters from the surface of the Caspian Sea. Shell sands are widespread on the Caspian shelf, deep-water areas are covered with silty sediments, and in some areas there is an outcrop of bedrock.
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 temperature of the Caspian 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 is 44 degrees.
The average annual rainfall is 200 millimeters per year, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters off the southwestern subtropical coast. The 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 is up to 1400 millimeters per year.
Winds often blow on the territory of the Caspian Sea, their average annual speed is 3-7 meters per second, north winds prevail in the wind rose. In the autumn and winter months, the winds increase, the wind speed often reaches 35-40 meters per second. The most windy territories are the Apsheron Peninsula and the environs of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.
The circulation of water in the Caspian Sea is connected with the runoff and winds. Since most of the water flow falls on the Northern Caspian, northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current is divided into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.
The fauna of the Caspian Sea is represented by 1810 species, of which 415 are vertebrates. 101 species of fish are registered in the Caspian world, and most of the world's stocks of sturgeon are concentrated in it, as well as such freshwater fish as vobla, carp, pike perch. The Caspian Sea is the habitat of such fish as carp, mullet, sprat, kutum, bream, salmon, perch, pike. The Caspian Sea is also inhabited by a marine mammal - the Caspian seal. Since March 31, 2008, 363 dead seals have been found on the coast of the Caspian Sea in Kazakhstan.
The flora of the Caspian Sea and its coast is represented by 728 species. Of the plants in the Caspian Sea, algae predominate - blue-green, diatoms, red, brown, char and others, of flowering - zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought into the Caspian Sea by man either consciously or on the bottoms of ships.
The Caspian Sea is the largest drainless lake on Earth, located at the junction of Europe and Asia, called the sea due to the fact that its bed is composed of oceanic-type earth's crust. The Caspian Sea is a drainless 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, according to 2009 data it was 27.16 m below sea level. 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 about 1200 kilometers, from west to east - from 195 to 435 kilometers, an average of 310-320 kilometers. The Caspian Sea is conditionally 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 North and Middle Caspian runs along the line of about. Chechnya - Cape Tyub-Karagansky, between the Middle and South Caspian - along the line of about. Residential - Cape Gan-Gulu. The area of the Northern, Middle and Southern Caspian is 25, 36, 39 percent respectively.
The length of the coastline of the Caspian Sea is estimated at about 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 shores are low and swampy, and the water surface is covered with thickets in many places. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding coasts are on the west coast in the area of the Apsheron Peninsula and on the east coast in the area of the Kazakh Gulf and Kara-Bogaz-Gol. The territory adjacent to the Caspian Sea is called the Caspian Sea.
The Caspian Sea is one of the most amazing enclosed bodies of water on Earth.
Over the centuries, the sea has changed more than 70 names. The modern came from the Caspians - the tribes inhabiting the central and southeastern part of Transcaucasia 2 thousand years BC.
Geography of the Caspian Sea
The Caspian Sea is located at the junction of Europe with Asia and is geographically divided into the South, North and Middle Caspian. The middle and northern part of the sea belongs to Russia, the southern part to Iran, the eastern part to Turkmenistan and Kazakhstan, and the southwestern part to Azerbaijan. For many years, the Caspian states have been dividing the Caspian water area among themselves, and quite sharply at that.
Lake or sea?
In fact, the Caspian Sea is the world's largest lake, but it has a number of marine features. These include: a large body of water, strong storms with high waves, high and low tides. But the Caspian has no natural connection with the World Ocean, which makes it impossible to call it a sea. At the same time, thanks to the Volga and artificially created channels, such a connection appeared. The salinity of the Caspian Sea is 3 times lower than the usual sea level, which does not allow classifying the reservoir as a sea.
There were times when the Caspian Sea was indeed part of the World Ocean. Several tens of thousands of years ago, the Caspian was connected to the Sea of Azov, and through it to the Black and Mediterranean. As a result of long-term processes occurring in the earth's crust, the Caucasus Mountains formed, which isolated the reservoir. Communication between the Caspian and Black Seas for a long time was carried out through the strait (Kumo-Manych depression) and gradually ceased.
Physical quantities
Area, volume, depth
The area, volume and depth of the Caspian Sea are not constant and directly depend on the water level. On average, the area of \u200b\u200bthe reservoir is 371,000 km², the volume is 78,648 km³ (44% of all world lake water reserves).
(Depth of the Caspian Sea in comparison with lakes Baikal and Tanganyika)
The average depth of the Caspian is 208 m, the northern part of the sea is considered the shallowest. The maximum depth is 1025 m, noted in the South Caspian depression. In depth, the Caspian is second only to Baikal and Tanganyika.
The length of the lake from north to south is about 1200 km, from west to east an average of 315 km. The length of the coastline is 6600 km, with islands - about 7 thousand km.
coast
Basically, the coast of the Caspian Sea is low-lying and smooth. In the northern part, it is heavily indented by the river channels of the Urals and the Volga. The swampy local shores are located very low. The eastern shores are adjacent to semi-desert zones and deserts, covered with limestone deposits. The most winding coasts are in the west in the region of the Apsheron Peninsula, and in the east - in the area of the Kazakh Gulf and Kara-Bogaz-Gol.
sea water temperature
(The temperature of the Caspian Sea at different times of the year)
The average water temperature in the Caspian in winter ranges from 0 °C in the northern part to +10 °C in the south. In the waters of Iran, the temperature does not fall below +13 °C. With the onset of cold weather, the shallow northern part of the lake is covered with ice, which lasts for 2-3 months. The thickness of the ice cover is 25-60 cm, at especially low temperatures it can reach 130 cm. In late autumn and winter, drifting ice floes can be observed in the north.
In summer, the average surface water temperature in the sea is + 24 °C. Most of the sea warms up to +25 °C ... +30 °C. Warm water and beautiful sandy, occasionally shell and pebble beaches create excellent conditions for a full-fledged beach holiday. In the eastern part of the Caspian Sea, near the city of Begdash, anomalously low water temperatures persist in the summer months.
Nature of the Caspian Sea
Islands, peninsulas, bays, rivers
The Caspian Sea includes about 50 large and medium-sized islands, the total area of which is 350 km². The largest of them are: Ashur-Ada, Garasu, Gum, Dash and Boyuk-Zira. The largest peninsulas are: Agrakhansky, Absheronsky, Buzachi, Mangyshlak, Miankale and Tyub-Karagan.
(Tyuleniy Island in the Caspian Sea, part of the Dagestan Reserve)
The largest bays of the Caspian include: Agrakhan, Kazakh, Kizlyar, Dead Kultuk and Mangyshlak. In the east is the salt lake Kara-Bogaz-Gol, previously a lagoon connected to the sea by a strait. In 1980, a dam was built on it, through which water from the Caspian goes to Kara-Bogaz-Gol, where it then evaporates.
130 rivers flow into the Caspian Sea, located mainly in its northern part. The largest of them: Volga, Terek, Sulak, Samur and Ural. The average annual runoff of the Volga is 220 km³. 9 rivers have a delta-shaped mouth.
Flora and fauna
About 450 species of phytoplankton live in the Caspian Sea, including algae, aquatic and flowering plants. Of the 400 species of invertebrates, worms, crustaceans and mollusks predominate. There are a lot of small shrimp in the sea, which is an object of fishing.
More than 120 species of fish live in the Caspian and the delta. Fishing objects are sprat (“Kilkin fleet”), catfish, pike, bream, pike perch, kutum, mullet, vobla, rudd, herring, white fish, pike perch, goby, grass carp, burbot, asp and pike perch. Stocks of sturgeon and salmon are currently depleted, however, the sea is the largest supplier of black caviar in the world.
Fishing in the Caspian Sea is allowed all year round except for the period from late April to late June. On the coast there are many fishing bases with all amenities. Fishing in the Caspian is a great pleasure. In any part of it, including in large cities, the catch is unusually rich.
The lake is famous for its large variety of waterfowl. Geese, ducks, loons, gulls, waders, sea eagles, geese, swans and many others come to the Caspian during migration or nesting. The largest number of birds - over 600 thousand individuals is observed in the mouths of the Volga and the Urals, in the bays of Turkmenbashi and Kyzylagach. During the hunting season, a huge number of fishermen come here not only from Russia, but also from countries near and far abroad.
The only mammal lives in the Caspian Sea. This is the Caspian seal or seal. Until recently, the seals swam close to the beaches, everyone could admire the amazing animal with round black eyes, the seals behaved very friendly. Now the seal is on the verge of extinction.
Cities on the Caspian Sea
Baku is the largest city on the coast of the Caspian Sea. The population of one of the most beautiful cities in the world is over 2.5 million people. Baku is spread out on the most picturesque Absheron peninsula and is surrounded on three sides by the waters of the warm and oil-rich Caspian Sea. Smaller cities: the capital of Dagestan - Makhachkala, Kazakh Aktau, Turkmen Turkmenbashi and Iranian Bandar Anzeli.
(Baku Bay, Baku - a city on the Caspian Sea)
Interesting Facts
Scientists are still arguing about whether to call a reservoir a sea or a lake. The level of the Caspian Sea is gradually decreasing. The Volga delivers most of the water to the Caspian. 90% of black caviar is mined in the Caspian Sea. Among them, the most expensive is Almas beluga caviar ($2,000 per 100 g).
Companies from 21 countries are participating in the development of oil fields in the Caspian Sea. According to Russian estimates, hydrocarbon reserves in the sea amount to 12 billion tons. American scientists claim that one fifth of the world's hydrocarbon reserves are concentrated in the depths of the Caspian Sea. This is more than the combined reserves of such oil-producing countries as Kuwait and Iraq.
