Where is the source of the Caspian Sea. Caspian Sea (largest lake)

The Caspian Sea is the most big lake On the Earth. It is called the sea because of its size and bed, which is folded like an ocean basin. The area is 371,000 square meters, the depth is 1025 m. The list of rivers flowing into the Caspian Sea includes 130 names. The largest of them are: Volga, Terek, Samur, Sulak, Ural and others.

Caspian Sea

It took 10 million years before the Caspian was formed. The reason for its formation is that the Sarmatian Sea, having lost contact with the World Ocean, was divided into two bodies of water, which were called the Black and Caspian Seas. Thousands of kilometers of waterless road stretch between the latter and the World Ocean. It is located at the junction of two continents - Asia and Europe. Its length in the north-south direction is 1200 km, west-east - 195-435 km. The Caspian Sea is an internal drainage basin of Eurasia.

At the Caspian Sea, the water level is below the level of the World Ocean, moreover, it is subject to fluctuations. According to scientists, this is due to many factors: anthropogenic, geological, climatic. Currently average level water reaches 28 m.

The river network and wastewater are unevenly distributed along the coast. A few rivers flow into a part of the sea from the north side: Volga, Terek, Ural. From the west - Samur, Sulak, Kura. The east coast is characterized by the absence of permanent streams. Differences in space in the flow of waters that bring rivers to the Caspian are important geographic feature this reservoir.

Volga

This river is one of the largest in Europe. It is the sixth largest in Russia. In terms of the catchment area, it is second only to the Siberian rivers flowing into the Caspian Sea, such as the Ob, Lena, Yenisei, Irtysh. For the source from which the Volga originates, the key is taken near the Volgoverkhovye village of the Tver region on the Valdai Upland. Now at the source there is a chapel attracting the attention of tourists, for whom it is a pride to step over the very beginning of the mighty Volga.

A small, fast stream is gradually gaining strength and becomes a huge river. Its length is 3690 km. The source is 225 m above sea level. Among the rivers flowing into the Caspian Sea, the Volga is the largest. Its path runs through many regions of our country: Tver, Moscow, Nizhny Novgorod, Volgograd and others. The territories through which it flows are Tatarstan, Chuvashia, Kalmykia and Mari El. The Volga is the location of millionaire cities - Nizhny Novgorod, Samara, Kazan, Volgograd.

Volga delta

The main channel of the river is divided into channels. A definite shape of the mouth is formed. It is called delta. Its beginning is the place where the Buzan branch separates from the Volga river bed. The delta is located 46 km north of the city of Astrakhan. It includes channels, branches, small rivers. There are several main branches, but only Akhtuba is navigable. Among all the rivers in Europe, the Volga has the largest delta, which is the rich fish region of this basin.

It lies lower than the ocean level, at 28 m. The mouth of the Volga is the location of the southernmost Volga city of Astrakhan, which in the distant past was the capital of the Tatar Khanate. Later in early XVIII century (1717), Peter 1 endowed the city with the status of "the capital of the Astrakhan province". During his reign, the main attraction of the city, the Assumption Cathedral, was built. Its Kremlin is made of white stone brought from the capital of the Golden Horde, Saray. The mouth is divided by arms, the largest of which are: Bolda, Bakhtemir, Buzan. Astrakhan is a southern city spread over 11 islands. Today it is a city of shipbuilders, sailors and fishermen.

Currently, the Volga needs protection. For this purpose, a reserve has been established in the place where the river flows into the sea. The Volga Delta, the largest river flowing into the Caspian Sea, is replete with unique flora and fauna: sturgeon fish, lotuses, pelicans, flamingos and others. Immediately after the 1917 revolution, a law was passed on their protection by the state as part of the Astrakhan reserve.

Sulak river

It is located in Dagestan, flows through its territory. It feeds on the waters of melted snows that flow from the mountains, as well as tributaries: Maly Sulak, Chvakhun-bak, Akh-su. Water also enters Sulak through the canal from the Aksai and Aktash rivers.

The source is formed by the confluence of two rivers that originate in the basins: Didoiskaya and Tushinskaya. The length of the Sulaks River is 144 km. Its pool has a fairly large area - 15 200 square meters. It flows along the canyon with the same name as the river, then along the Akhetlinsky gorge and finally comes out onto the plane. Skirting the Agrakhan Bay from the south, Sulak flows into the sea.

The river provides Kaspiysk and Makhachkala with drinking water, hydroelectric power plants, urban-type settlements Sulak and Dubki, as well as the small town of Kizilyurt are located on it.

Samur

The river got this name for a reason. The name translated from the Caucasian language (one of them) means "middle". Indeed, the waterway along the Samur River marked the border between the states of Russia and Azerbaijan.

The sources of the river are glaciers and springs, originating in the spurs of the Caucasian ridge from the northeastern side, not far from Guton Mountain. The height above sea level is 3200 m. Samur has a length of 213 km. The height in the upper reaches and the mouth differs by three kilometers. The catchment basin has an area of almost five thousand square meters.

The places where the river flows are narrow gorges located between the mountains. great height composed of shale and sandstone, which is why the water here is muddy. The Samur basin has 65 rivers. Their length reaches 10 km and more.

Samur: the valley and its description

The valley of this river in Dagestan is the most densely populated area. Derbent is located near the mouth - oldest city the world. The banks of the Samur River are home to twenty or more species of relict flora. Endemics, endangered and rare species listed in the Red Book grow here.

In the delta of the river, there is a relict forest, which is the only one in Russia. The liana forest is a fairy tale. Huge trees of the rarest and most common species, intertwined with lianas, grow here. The river is rich in valuable fish species: mullet, pike perch, pike, catfish and others.

Terek

The river got its name from the Karachai-Balkarian peoples who lived along its banks. They called her "Terk Suu", which means "rushing water" in translation. The Ingush and Chechens called it Lomeki - "mountain water".

The beginning of the river is the territory of Georgia, the Zigla-Khokh glacier is a mountain located on the slope of the Caucasian ridge. It is under glaciers all year round. One of them melts when sliding down. A small stream forms, which is the source of the Terek. It is located at an altitude of 2713 m above sea level. The length of the river flowing into the Caspian Sea is 600 km. When it flows into the Caspian, the Terek is divided into many branches, resulting in the formation of a vast delta, its area is 4000 square meters. In some places it is very swampy.

The channel in this place has changed several times. The old sleeves are now being turned into canals. The middle of the last century (1957) was marked by the construction of the Kargalinsky hydroelectric complex. It is used to supply water to the canals.

How is the Terek replenished?

The river has a mixed feeding, but for the upper course, waters from the melting of glaciers play an important role, they fill the river. In this regard, 70% of the runoff occurs in spring and summer, that is, at this time the water level in the Terek is the highest, and the lowest - in February. The river freezes if winters are characterized by a harsh climate, but the freeze-up is unstable.

The river is not clean and transparent. Turbidity of water is large: 400-500 g / m 3. Every year the Terek and its tributaries pollute the Caspian Sea, pouring into it from 9 to 26 million tons of various suspensions. This is due to the rocks from which the banks are composed, and they are clayey.

Mouth Terek

Sunzha is the most large influx, flowing into the Terek, the lower reaches of which are counted precisely from this river. By this time, the Terek has been flowing for a long time across the flat terrain, leaving the mountains behind the Elkhotovo gate. The bottom here is composed of sand and pebble rocks, the current slows down, and in some places it stops altogether.

The mouth of the Terek River has an unusual appearance: the channel here is raised above the valley, along outward appearance resembles a canal, which is fenced off by an embankment of great height. The water level rises above the land level. This phenomenon is due to a natural cause. Since the Terek is a turbulent river, it brings sand and stones in large quantities from the Caucasian ridge. Considering that the current in the lower reaches is weak, part of them settles here and does not reach the sea. For the inhabitants of this area, sediments are both a threat and a boon. When they are washed away by water, floods of great destructive force occur, this is very bad. But in the absence of floods, the soil becomes fertile.

Ural river

In ancient times (until the second half of the 18th century) the river was called Yaik. It was renamed in Russian by the decree of Catherine II in 1775. It was at this time that the Peasant War, led by Pugachev, was suppressed. The name has survived to this day in the Bashkir language, and in Kazakhstan it is official. The Ural is the third longest in Europe, the largest of this river is only the Volga and Danube.

The Ural originates in Russia, on the slope of the Round Hill of the Uraltau ridge. The source is a spring that gushes out of the ground at an altitude of 637 m above sea level. At the beginning of its path, the river flows in the north-south direction, but after the plateau meets on the way, it makes sharp turn and continues to flow northwestward. However, beyond Orenburg, its direction again changes to the south-west, which is considered the main one. Having overcome the winding path, the Ural flows into the Caspian Sea. The length of the river is 2,428 km. The wellhead is divided into sleeves and tends to become shallow.

The Ural is a river along which there is a natural water border between Europe and Asia, with the exception of the upper course. It is an internal European river, but its headwaters east of the Ural Range are the territory of Asia.

The importance of the rivers of the Caspian

The rivers flowing into the Caspian Sea are of great importance. Their waters are used for human and animal consumption, domestic needs, agricultural and industrial needs. Hydroelectric power plants are being built on the rivers, the energy of which is demanded by humans for various purposes. The river basins are full of fish, algae, and shellfish. Even in ancient times, people chose river valleys for future settlements. And now cities and towns are being built on their banks. Rivers are plowed by passenger and transport ships, performing important tasks for the transport of passengers and goods.

CASPIAN SEA (Caspian Sea), the largest on the globe closed reservoir, closed-drain brackish lake. Located on the southern border of Asia and Europe, it washes the shores of Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Due to the size, originality natural conditions and the complexity of the hydrological processes of the Caspian Sea is usually attributed to the class of closed inland seas.

The Caspian Sea is located in a vast area of internal flow 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 maximum depth is 1025 m. With a width of 200 to 400 km, the sea is elongated along the meridian by 1030 km.

The largest bays: in the east - Mangyshlak, Kara-Bogaz-Gol, Turkmenbashi (Krasnovodsky), Turkmen; in the west - Kizlyarsky, Agrakhansky, Kyzylagaj, 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; the larger ones are Kulaly, Morskoy, Tyuleniy, Chechen. On the western shores - the Apsheron archipelago, to the south lie the islands of the Baku archipelago, east coast- the narrow Ogurchinsky island stretched from north to south.

The northern shores of the Caspian Sea are low-lying and very sloping, characterized by a wide development of drylands, which are formed as a result of surge phenomena; here are also developed delta shores (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, to the south of the Apsheron Peninsula, for the most part, the accumulative deltaic type with numerous barrows and spits. The southern shores are low. The eastern shores are mostly deserted and low-lying, composed of sands.

Relief and geological structure bottom.

The Caspian Sea is located in a zone of increased seismic activity. In the city of Krasnovodsk (now Turkmenbashi) in 1895, there was a strong earthquake with a magnitude of 8.2 on the Richter scale. On the islands and the 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 washed away by waves and reappear.

According to the peculiarities of the physical and geographical conditions and the nature of the bottom relief in the Caspian Sea, it is customary to distinguish the North, Middle and South Caspian. The North Caspian is distinguished by exceptional shallowness, it is located entirely within the shelf with an average depth of 4-5 m.Even small changes in the level here at low-lying coasts lead to significant fluctuations in the area of the water surface, therefore the sea borders in the northeastern part on the maps small scale show with a dotted line. The greatest depths (about 20 m) are observed only near the conditional border with the Middle Caspian, which is drawn along the line connecting the Chechen island (north of the Agrakhan peninsula) with the Tyub-Karagan cape on the Mangyshlak peninsula. In the relief of the bottom of the Middle Caspian, the Derbent depression is distinguished (the maximum depth is 788 m). The border between the Middle and South Caspian Sea runs over the Apsheron rapids with depths of up to 180 m along the line from Chilov Island (east of the Apsheron Peninsula) to Cape Kuuli (Turkmenistan). The basin of the South Caspian 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 falls on the Middle Caspian, in the North Caspian, due to shallow depths, there is less than 1% of the Caspian waters. In general, shelf areas prevail in the bottom relief of the Caspian Sea (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. Terrigenous shell sands, shells, oolitic sands are widespread on the shelf; 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, bedrock of the Neogene age is exposed. Mirabilite accumulates in the Ka-ra-Bogaz-Gol Bay.

Tectonically, within the Northern Caspian, the southern part of the Caspian syneclise of the East European platform is distinguished, which is framed in the south by the Astrakhan-Aktobe zone, composed of Devonian-Lower Permian carbonate rocks, lying on a volcanic base and containing large deposits of oil and natural combustible gas. From the southwest, the Paleozoic fold formations of the Donetsk-Caspian zone (or the Karpinsky ridge) are thrust onto the syneclise, which is a protrusion of the basement of the young Scythian (in the west) and Turan (in the east) platforms, which are divided at the bottom of the Caspian Sea by the Agrakhan-Guryev fault (left strike-slip) 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 folded system of the Greater Caucasus. The sedimentary cover of the platform and trough, composed of Jurassic and younger sediments, encloses oil and combustible gas deposits in local uplifts. The Absheron sill, separating the Middle Caspian from the South, is a closing link of the Cenozoic fold systems of the Greater Caucasus and Kopetdag. The South Caspian basin of the Caspian Sea with oceanic or transitional type crust is filled with a thick (over 25 km) complex of Cenozoic sediments. The South Caspian Basin contains numerous large deposits hydrocarbons.

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 Paratethys). By the beginning of the Pliocene, it had lost its connection with the Black Sea. The North and Middle Caspian were drained, and through them stretched the valley of the paleo-Volga, the delta of which was located in the area of the Apsheron Peninsula. Deltaic sediments have become the main reservoir of oil and natural combustible gas deposits in Azerbaijan and Turkmenistan. In the Late Pliocene, due to the Akchagyl transgression, the area of the Caspian Sea greatly increased and the connection with the World Ocean was temporarily renewed. The waters of the sea covered more than just the bottom modern depression The Caspian Sea, but also the adjacent territories. In the Quaternary time, the transgressions (Absheron, Baku, Khazar, Khvalynskaya) alternated with regressions. The southern half of the Caspian Sea is located in a zone of increased seismic activity.

Climate... Strongly elongated from north to south, the Caspian Sea is located within several climatic zones... In the northern part, the climate is temperate continental, on the western coast it is moderately warm, the southwestern and southern coasts lie within the subtropics, on the eastern coast the desert climate prevails. In winter, over the North and Middle Caspian, the weather is formed under the influence of the Arctic continental and sea air and the South Caspian is often affected by southern cyclones. The weather in the west is unstable 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 under the influence of the Iranian-Afghani minimum, which together creates dry, stable warm weather. Winds of the northern and north-western (up to 40%) and southeastern (about 35%) directions prevail over the sea. The average wind speed is about 6 m / s, in central regions sea up to 7 m / s, in the area of the Apsheron Peninsula - 8-9 m / s. Northern stormy "Baku Nords" reach a speed of 20-25 m / s. The lowest average monthly air temperatures of -10 ° С are observed in January-February in the northeastern regions (in the most severe winters they reach -30 ° С), in southern regions 8-12 ° C. In July - August, the average monthly temperatures over the entire sea area are 25-26 ° С, with a maximum up to 44 ° С on the eastern coast. Distribution atmospheric precipitation very uneven - from 100 mm per year on the eastern banks to 1700 mm in Lankaran. On the open sea, on average, about 200 mm of precipitation falls per year.

Hydrological regime. Changes in the water balance of an enclosed sea strongly affect the change in the volume of water and the corresponding fluctuations in the 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, atmospheric precipitation 77/20, groundwater runoff 4/1, evaporation 377/97, runoff in Kara-Bogaz- Goal 13/3, which forms a negative water balance of 9 km 3, or 3 cm of the layer, per year. According to paleogeographic data, over the past 2000 years, the range of fluctuations in the level of the Caspian Sea reached at least 7 m. -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 Azov Sea. 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 mainly determined by fluctuations in climatic characteristics. Seasonal fluctuations in the level of the Caspian Sea are associated with the unevenness of the flow of river runoff (primarily the Volga runoff), therefore, the lowest level is observed in winter, the highest in summer. Short-term abrupt changes in the level are associated with surges, they are most pronounced in shallow northern regions and during storm surges can reach 3-4 m. Such surges cause flooding of significant coastal land areas. In the Middle and South Caspian Sea, surging level fluctuations are on 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, the duration is up to one day. In the Caspian, as in any closed water body, 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 fluctuations usually does not exceed 20-30 cm.

River runoff in the Caspian Sea is extremely unevenly distributed. 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 with the Urals and enters the shallow North Caspian. The rivers of the western coast - Kura, Samur, Sulak, Terek, etc. - give up to 10% of the runoff. Another 5% of fresh water is brought to the South Caspian by the rivers of the Iranian coast. The eastern desert shores are completely devoid of constant fresh flow.

Average speeds of wind currents are 15-20 cm / s, the highest - up to 70 cm / s. In the North Caspian, the prevailing winds create a flow directed along the northwest 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. At the Absheron Peninsula, the current bifurcates. Its part in the open sea flows into the cyclonic circulation of the Middle Caspian, and the coastal one bends around the shores of the South Caspian and turns to the north, being included in the coastal current that bends around the entire eastern coast. The average state of movement of surface Caspian waters is often disturbed due to variability of wind conditions and other factors. For example, in the northeastern shallow water area, a local anticyclonic circulation may arise. Two anticyclonic eddies are often observed in the South Caspian. In the Middle Caspian in the warm season, stable northwestern winds create a southern transport along the eastern coast. In light winds and during calm weather, currents may have different directions.

Wind waves develop very strongly, since the prevailing winds have a long acceleration length. The excitement develops mainly in the northwest and southeast directions. Strong storms are observed in the open water area of the Middle Caspian, in the regions of Makhachkala, the Absheron Peninsula and the Mangyshlak Peninsula. The average wave height of the highest frequency of occurrence is 1-1.5 m, at wind speeds of more than 15 m / s, it increases to 2-3 m. 10 m.

The water temperature on the sea surface in January - February in the Northern Caspian is close to the freezing point (about -0.2 - -0.3 ° C) and gradually rises southward to 11 ° C off the coast of Iran. Summer surface waters warm up to 23-28 ° С everywhere, except for the eastern shelf of the Middle Caspian, where seasonal coastal upwelling develops in July-August and the water temperature on the surface drops to 12-17 ° С. In winter, due to intense convective mixing, the water temperature changes little with depth. In summer, a seasonal thermocline (layer of abrupt temperature change) is formed under the upper heated layer at horizons of 20-30 m, separating deep cold waters from warm surface waters. In the bottom layers of the waters of deep-water depressions, the temperature is maintained at 4.5-5.5 ° С in the Middle Caspian Sea and 5.8-6.5 ° С in the South all year round. Salinity in the Caspian Sea is almost 3 times lower than in the open regions of the World Ocean, and averages 12.8-12.9 ‰. It should be especially emphasized that salt composition 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 calcium and magnesium carbonates and sulfates due to the peculiar composition of the salts that enter the sea with river and underground runoff. The highest variability of salinity is observed in the Northern Caspian, where in the estuarine areas of the Volga and the Urals the water is fresh (less than 1 ‰), and as we move to the south, the salt content increases to 10-11 ‰ on the border with the Middle Caspian. The largest horizontal salinity gradients are characteristic of the frontal zone between sea and river waters. Differences in salinity between the Middle and South Caspian are small, salinity slightly increases from northwest to southeast, reaching 13.6 ‰ in the Turkmen Bay (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. The transparency of the water 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 belongs to the partially freezing seas. Ice conditions are observed annually only in the northern regions. The Northern Caspian is completely covered with sea ice, the Middle - partially (only in severe winters). Middle border sea ice runs in an arc facing the bulge to the north, from the Agrakhan peninsula in the west to the Tyub-Karagan peninsula in the east. Usually ice formation begins in mid-November in the far northeast and gradually spreads to the southwest. In January, the entire North Caspian is covered with ice, mostly fast ice (motionless). Drifting ice borders fast ice in a strip 20-30 km wide. Average ice thickness from 30 cm southern border up to 60 cm in the northeastern regions of the North Caspian, in hummock heaps - up to 1.5 m. The destruction of the ice cover begins in the second half of February. In severe winters, drifting ice is carried out to the south, along west coast, sometimes to the Absheron Peninsula. At the beginning of April, the sea is completely free of ice cover.

Research history... It is believed that the modern name of the Caspian Sea comes from the ancient tribes of the Caspians who inhabited the coastal regions in the 1st millennium BC; other historical names: Hyrkan (Irkan), Persian, Khazar, Khvalynskoe (Khvaliss), Khorezm, Derbent. The first mentions of the existence of the Caspian Sea date back to the 5th century BC. Herodotus was one of the first to assert that this reservoir is isolated, that is, it is a lake. In the works of Arab scientists of the Middle Ages, there is information that in the 13-16 centuries the Amu Darya partially flowed into this sea by one of the branches. Known numerous ancient Greek, Arab, 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 coastlines are close to modern ones, was compiled in 1720 using astronomical definitions by the Russian military hydrographers F.I.Soimonov and K. Verdun. In 1731, Soimonov published the first atlas, and soon the first printed pilot of the Caspian Sea. A new edition of the 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 second half of the 18th century was continued by I.V. Tokmachev, M.I. In 1807, a new map of the Caspian Sea was published, based on the latest inventories. In 1837, systematic instrumental observations of sea level fluctuations began in Baku. In 1847 the first Full description of the Kara-Bogaz-Gol bay. In 1878, the 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, expeditionary research on the hydrology and hydrobiology of the Caspian was conducted under the leadership of N.M. Soviet geologists I.M. Gubkin, D.V. and V.D. Golubyatnikovs, P.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 in the Caspian Sea, systematic and versatile research was launched aimed at studying the hydrometeorological regime, biological conditions and the 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. Caspian Marine Research Center (CaspMNITs), established in 1995 by a government decree Russian Federation, conducts research work in hydrometeorology, oceanography and ecology. The Caspian Scientific Research Institute of Fisheries (CaspNIRKh) traces its history from the Astrakhan Scientific Research Station [created in 1897, since 1930 the Volga-Caspian Scientific Fisheries Station, since 1948 the Caspian branch of the All-Russian Scientific Research Institute of Fisheries and Oceanography, since 1954 the Caspian Research Institute of Marine Fisheries and Oceanography (CaspNIRO), modern name since 1965]. CaspNIRKh is developing the foundations for the conservation and rational use of the biological resources of the Caspian Sea. It includes 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 self-precipitated mineral salts in the Kara-Bogaz-Gol Bay. The Caspian region is also known as a mass habitat for waterfowl and semi-aquatic birds. About 6 million migratory birds migrate through the Caspian Sea every year. In this regard, the Volga delta, the Kyzylagaj, North Cheleken and Turkmenbashi bays are recognized as international land under the Ramsar Convention. The estuaries 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 estuarine sections of rivers. Marine species are of commercial importance - herring, sprat, gobies, sturgeon; freshwater - carp, perch; Arctic "invaders" - salmon, white fish. Major ports: Astrakhan, Makhachkala in Russia; Aktau, Atyrau in Kazakhstan; Turkmenbashi in Turkmenistan; Bandar Torkemen, Bandar Anzali in Iran; Baku in Azerbaijan.

Ecological state. The Caspian Sea is under a powerful anthropogenic impact 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 catches of recent decades, poaching and a sharp deterioration in the ecological situation have put many valuable fish species on the brink of extinction. The living conditions have worsened not only for fish, but also for birds and sea animals (the Caspian seal). The countries washed by the waters of the Caspian Sea face the problem of creating a set of international measures to prevent pollution aquatic environment and developing the most effective environmental strategy for the near future. Stable ecological state observed only in parts of the sea remote from the coast.

Lit .: Caspian Sea. M., 1969; Comprehensive research The Caspian Sea. M., 1970. Issue. one; Gul K. K., Lappalainen T. N., Polushkin V. A. Caspian Sea. M., 1970; Zalogin B.S., Kosarev A.N. M., 1999; International tectonic map of the Caspian Sea and its framing / 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).

The Caspian Sea is the largest closed body of water on the planet Earth, located on the continent of Eurasia - in the border territories of the states of Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. In fact, it is a giant lake left after the disappearance of the ancient Tethys ocean. Nevertheless, there is every reason to consider it as an independent sea (this is indicated by salinity, a large area and a decent depth, the bottom of the oceanic crust and other signs). In terms of maximum depth, it is the third among closed bodies of water - after lakes Baikal and Tanganyika. In the northern part of the Caspian Sea (a few kilometers from the northern coast - parallel to it) passes geographic boundary between Europe and Asia.

Toponymy

Other names: throughout the history of mankind different nations The Caspian Sea had about 70 different names. The most famous of them: Khvalynskoe or Khvalisskoe (took place during the time of Ancient Rus, arose by the name of the people praises who lived in the Northern Caspian Sea and traded with the Russians), Girkanskoe or Dzhurdzhanskoe (derived from the alternative names of the city of Gorgan, located in Iran), Khazar, Abeskunskoe (by the name of the island and the city in the Kura delta - now flooded), Saraisk, Derbent, Sihai ...
Origin of name: according to one of the hypotheses, the Caspian Sea received its modern and most ancient name from a tribe of nomadic horse breeders Kaspiev who lived in the 1st millennium BC on the southwestern coast.

Morphometry

Drainage area: 3,626,000 km².
Mirror area: 371,000 km².
Length coastline: 7,000 km
Volume: 78 200 km³.
Average depth: 208 m.
Maximum depth: 1,025 m.

Hydrology

The presence of a constant flow: no, drainless.
Inflows:, Ural, Emba, Atrek, Gorgan, Heraz, Sefidrud, Astarchay, Kura, Pirsagat, Kusarchay, Samur, Rubas, Darvagchay, Uluchay, Shuraozen, Sulak, Terek, Kuma.
Bottom: very diverse. At shallow depths, sandy soil with an admixture of shells is common, in deep-water places it is silty. Pebble and rocky places can be found in the coastal strip (especially where mountain ranges adjoin the sea). In the estuarine areas, the underwater soil consists of river sediments. The Kara-Bogaz-Gol bay is notable for the fact that its bottom is a thick layer of mineral salts.

Chemical composition

Water: brackish.
Salinity: 13 g / l.
Transparency: 15 m.

Geography

Rice. 1. Map of the Caspian Sea Basin.

Coordinates: 41 ° 59′02 ″ s. sh., 51 ° 03'52 ″ in. etc.
Height above sea level:-28 m.
Coastal landscape: due to the fact that the coastline of the Caspian Sea is very long, and it itself is located in different geographic areas- The coastal landscape is diverse. In the northern part of the reservoir, the shores are low, swampy, in places of the deltas of large rivers cut by numerous channels. The eastern shores are mostly limestone - desert or semi-desert. The western and southern shores are adjacent to mountain ranges. The most indented coastline is observed in the west - in the area of the Apsheron Peninsula, as well as in the east - in the area of the Kazakh and Kara-Bogaz-Gol bays.
Settlements on the banks:
- Russia: Astrakhan, Derbent, Kaspiysk, Makhachkala, Olya.
- Kazakhstan: Aktau, Atyrau, Kuryk, Sogandyk, Bautino.
- Turkmenistan: Ekerem, Karabogaz, Turkmenbashi, Khazar.
- Iran: Astara, Balboser, Bender-Torkemen, Bender-Anzali, Neka, Chalus.
- Azerbaijan: Alat, Astara, Baku, Dubendi, Lankaran, Sangachaly, Sumgayit.

Interactive map

Ecology

The ecological situation in the Caspian Sea is far from ideal. Almost all large rivers flowing into it are polluted by drains industrial enterprises located upstream. This could not but affect the presence of pollutants in the waters and bottom sediments of the Caspian - over the past half century, their concentration has increased markedly, and the content of some heavy metals has already exceeded the permissible limits.

In addition, the waters of the Caspian Sea are constantly polluted by domestic wastewater from coastal cities, as well as during oil production on the continental shelf, and during its transportation.

Fishing in the Caspian Sea

Fish species:
Artificial settlement: not all of the above fish species in the Caspian Sea are indigenous. About 4 dozen species were caught by accident (for example, through the channels from the Black and Baltic seas), or were deliberately inhabited by humans. An example is mullet. Three Black Sea species of these fish - striped mullet, ostronos and singil - were released in the first half of the 20th century. Loban didn’t take root, but ostronos with singil have successfully acclimatized, and by now they have settled practically throughout the entire water area of the Caspian, having formed several commercial herds. At the same time, the fish feed faster than in the Black Sea, and reach larger sizes. In the second half of the last century (since 1962), attempts were also made to settle in the Caspian Sea such Far Eastern salmon fishes as pink salmon and chum salmon. In total, several billion fry of these fish were released into the sea for 5 years. The pink salmon did not survive in the new habitat, the chum salmon, on the contrary, successfully took root and even began to spawn in the rivers flowing into the sea. However, she could not reproduce in sufficient numbers and gradually disappeared. For her full natural reproduction while there are no favorable conditions (there are very few places where spawning and development of fry could be successful). To ensure them, reclamation of rivers is needed, otherwise, without human help (artificial sampling of eggs and its incubation), the fish will not be able to maintain their numbers.

Fishing spots

In fact, fishing is possible anywhere along the coast of the Caspian Sea, which can be reached by land or water. What species of fish will be caught at the same time depends on local conditions, but to a greater extent on whether rivers flow here. As a rule, in places where estuaries and deltas are located (especially large watercourses), the water in the sea is greatly desalinated, therefore freshwater fish (carp, catfish, bream, etc.) usually prevail in catches, and species characteristic of flowing rivers (barbel, shemaya). Of the marine species in desalinated areas, those for which salinity does not matter (mullet, some of the gobies) are caught. In certain periods of the year, semi-anadromous and anadromous species can be found here, feeding in the sea, and spawning in rivers (sturgeon, some of herring, Caspian salmon). In places where there are no rivers flowing into it, freshwater species are found in slightly smaller numbers, but at the same time marine fish appear, usually avoiding desalinated areas (for example, sea pike perch). Away from the coast, fish that prefer salt water and deep-sea species are caught.

Conventionally, there are 9 places or areas that are interesting in terms of fishing:

North Shore (RF)- this site is located on the northern coast of the Russian Federation (from the Volga delta to the Kizlyar Bay). Its main features are insignificant salinity of water (the lowest in the Caspian Sea), shallow depth, the presence of multiple shoals, islands, highly developed aquatic vegetation. In addition to the Volga delta with its numerous channels, bays and eriks, it also includes the near-estuarine seashore, called the Caspian peals. These places are popular with Russian fishermen, and for good reason: the conditions for fish are very favorable here, and there is also a good food base. The ichthyofauna in these parts may not be distinguished by the richness of species, but it is distinguished by its multiplicity, and its individual representatives reach very considerable sizes. Typically, the main catches are freshwater fish typical for the Volga basin. Most often caught: perch, pike perch, roach (more precisely - its varieties, called roach and ram), rudd, asp, sabrefish, bream, goldfish, carp, catfish, pike. Bersh, silver bream, white-eyed, blue bream are somewhat less common. Representatives of sturgeon (sturgeon, stellate sturgeon, beluga, etc.), salmon (nelma, brown trout - Caspian salmon) are also found in these places, but fishing is prohibited.
Northwest coast (RF)- this section covers West Coast Russian Federation (from Kizlyar Bay to Makhachkala). The rivers Kuma, Terek and Sulak flow here - they carry their waters both along natural channels and artificial canals. There are bays in this area, some of which are quite large (Kizlyarsky, Agrakhansky). The sea in these places is shallow. Freshwater fish predominate in the catches: pike, perch, carp, catfish, rudd, bream, barbel, etc.
West Bank (RF)- from Makhachkala to the border of the Russian Federation with Azerbaijan. A site where mountain ranges adjoin the sea. The salinity of the water here is slightly higher than in previous places, therefore, in the catches of fishermen, marine species are more common (sea pike perch, mullet, herring). However, freshwater fish are by no means uncommon.
West Bank (Azerbaijan)- from the border of the Russian Federation with Azerbaijan along the Absheron Peninsula. Continuation of the site, where mountain ranges adjoin the sea. Fishing here is even more similar to the typical sea one, thanks to such fish as ostronos and singil (mullet) and several species of gobies, which are also caught here. In addition to them, there are kutum, herring, and some typically freshwater species, for example, the carp.
Southwest coast (Azerbaijan)- from the Absheron Peninsula to the border of Azerbaijan with Iran. Most of this site is occupied by the Kura River delta. The same fish species that were listed in the previous paragraph are caught here, but freshwater fish are more often caught.
North coast (Kazakhstan)- this section covers the northern coast of Kazakhstan. The Ural delta and the Akzhaiyk state reserve are located here, so fishing directly in the river delta and in some adjacent water area is prohibited. Fishing is possible only outside the reserve - upstream of the delta, or in the sea - at some distance from it. Fishing near the Ural delta has much in common with fishing at the confluence of the Volga - almost the same species of fish are found here.
North-east coast (Kazakhstan)- from the mouth of the Emba to Cape Tyub-Karagan. Unlike the northern part of the sea, where the water is greatly diluted by the large rivers flowing into it, its salinity somewhat increases here, so those fish species appear that avoid freshened areas, for example, sea pike perch, which is caught in the Dead Kultuk Bay. Other representatives of the marine fauna are also often found in the catches.
East coast (Kazakhstan, Turkmenistan)- from Cape Tyub-Karagan to the border of Turkmenistan and Iran. Differs in almost complete absence of flowing rivers. The salinity of the water is at its maximum here. Of the fish in these places, marine species predominate, the main catch is mullet, sea pike perch and gobies.
South Coast (Iran)- covers the southern coast of the Caspian. Along the entire length of this section, the sea is adjacent to mountain range Elburs. Many rivers flow here, most of which are represented by small streams, there are also several medium and one large river. Among fish, in addition to marine species, there are also some freshwater, as well as semi-anadromous and anadromous species, for example, sturgeon.

Fishing features

The most popular and catchy amateur tackle, which is used on the Caspian coast, is a heavy spinning rod converted into a "sea donkey". Usually it is equipped with a strong reel, on which a rather thick line (0.3 mm and more) is wound. The thickness of the line is determined not so much by the size of the fish as by the mass of a rather heavy sinker, which is necessary for ultra-long casting (in the Caspian it is generally believed that the further from the coast the casting point is, the better). After the sinker, there is a thinner line - with several leads. Shrimps and amphipods that live in coastal thickets of seaweed are used as a bait - if you intend to fish for sea fish, or an ordinary bait like a worm, May beetle larvae and others - if freshwater species are found in the fishing area.

At the mouths of rivers flowing in, other gear can be used, such as a float rod, feeder and traditional spinning rod.

kasparova2 majorov2006 g2gg2g-61.

Photo 8. Sunset in Aktau.

The Caspian Sea is the largest closed body of water on the planet Earth, located on the continent of Eurasia - in the border territories of the states of Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. In fact, it is a giant lake left after the disappearance of the ancient Tethys ocean. Nevertheless, there is every reason to consider it as an independent sea (this is indicated by salinity, a large area and a decent depth, a bottom from the oceanic crust and other signs). In terms of maximum depth, it is the third among closed bodies of water - after lakes Baikal and Tanganyika. In the northern part of the Caspian Sea (a few kilometers from the northern coast - parallel to it) there is a geographical border between Europe and Asia.

Toponymy

Other names: throughout the history of mankind, the Caspian Sea had about 70 different names among different peoples. The most famous of them: Khvalynskoe or Khvalisskoe (took place during the time of Ancient Rus, arose by the name of the people praises who lived in the Northern Caspian Sea and traded with the Russians), Girkanskoe or Dzhurdzhanskoe (derived from the alternative names of the city of Gorgan, located in Iran), Khazar, Abeskunskoe (by the name of the island and the city in the Kura delta - now flooded), Saraisk, Derbent, Sihai ...
Origin of name: according to one of the hypotheses, the Caspian Sea received its modern and most ancient name from a tribe of nomadic horse breeders Kaspiev who lived in the 1st millennium BC on the southwestern coast.

Morphometry

Drainage area: 3,626,000 km².
Mirror area: 371,000 km².
Coastline length: 7,000 km
Volume: 78 200 km³.
Average depth: 208 m.
Maximum depth: 1,025 m.

Hydrology

The presence of a constant flow: no, drainless.
Inflows:, Ural, Emba, Atrek, Gorgan, Heraz, Sefidrud, Astarchay, Kura, Pirsagat, Kusarchay, Samur, Rubas, Darvagchay, Uluchay, Shuraozen, Sulak, Terek, Kuma.
Bottom: very diverse. At shallow depths, sandy soil with an admixture of shells is common, in deep-water places it is silty. Pebble and rocky places can be found in the coastal strip (especially where mountain ranges adjoin the sea). In the estuarine areas, the underwater soil consists of river sediments. The Kara-Bogaz-Gol bay is notable for the fact that its bottom is a thick layer of mineral salts.

Chemical composition

Water: brackish.
Salinity: 13 g / l.
Transparency: 15 m.

Geography

Rice. 1. Map of the Caspian Sea Basin.

Coordinates: 41 ° 59′02 ″ s. sh., 51 ° 03'52 ″ in. etc.
Height above sea level:-28 m.
Coastal landscape: due to the fact that the coastline of the Caspian Sea is very long, and it itself is located in different geographic zones, the coastal landscape is diverse. In the northern part of the reservoir, the shores are low, swampy, in places of the deltas of large rivers cut by numerous channels. The eastern shores are mostly limestone - desert or semi-desert. The western and southern shores are adjacent to mountain ranges. The most indented coastline is observed in the west - in the area of the Apsheron Peninsula, as well as in the east - in the area of the Kazakh and Kara-Bogaz-Gol bays.
Settlements on the banks:
- Russia: Astrakhan, Derbent, Kaspiysk, Makhachkala, Olya.
- Kazakhstan: Aktau, Atyrau, Kuryk, Sogandyk, Bautino.
- Turkmenistan: Ekerem, Karabogaz, Turkmenbashi, Khazar.
- Iran: Astara, Balboser, Bender-Torkemen, Bender-Anzali, Neka, Chalus.
- Azerbaijan: Alat, Astara, Baku, Dubendi, Lankaran, Sangachaly, Sumgayit.

Interactive map

Ecology

The ecological situation in the Caspian Sea is far from ideal. Practically all large rivers flowing into it are polluted by wastewater from industrial enterprises located upstream. This could not but affect the presence of pollutants in the waters and bottom sediments of the Caspian - over the past half century, their concentration has increased markedly, and the content of some heavy metals has already exceeded the permissible limits.

Fishing in the Caspian Sea

Fish species:
Artificial settlement: not all of the above fish species in the Caspian Sea are indigenous. About 4 dozen species came by accident (for example, through canals from the Black and Baltic Seas), or were deliberately inhabited by humans. An example is mullet. Three Black Sea species of these fish - striped mullet, ostronos and singil - were released in the first half of the 20th century. Loban didn’t take root, but ostronos with singil have successfully acclimatized, and by now they have settled practically throughout the entire water area of the Caspian, having formed several commercial herds. At the same time, the fish feed faster than in the Black Sea, and reach larger sizes. In the second half of the last century (since 1962), attempts were also made to settle in the Caspian Sea such Far Eastern salmon fishes as pink salmon and chum salmon. In total, several billion fry of these fish were released into the sea for 5 years. The pink salmon did not survive in the new habitat, the chum salmon, on the contrary, successfully took root and even began to spawn in the rivers flowing into the sea. However, she could not reproduce in sufficient numbers and gradually disappeared. So far, there are no favorable conditions for its full-fledged natural reproduction (there are very few places where spawning and development of fry could successfully occur). To ensure them, reclamation of rivers is needed, otherwise, without human help (artificial sampling of eggs and its incubation), the fish will not be able to maintain their numbers.

Fishing spots

Conventionally, there are 9 places or areas that are interesting in terms of fishing:

North Shore (RF)- this site is located on the northern coast of the Russian Federation (from the Volga delta to the Kizlyar Bay). Its main features are insignificant salinity of water (the lowest in the Caspian Sea), shallow depth, the presence of multiple shoals, islands, highly developed aquatic vegetation. In addition to the Volga delta with its numerous channels, bays and eriks, it also includes the near-estuarine seashore, called the Caspian peals. These places are popular with Russian fishermen, and for good reason: the conditions for fish are very favorable here, and there is also a good food base. The ichthyofauna in these parts may not be distinguished by the richness of species, but it is distinguished by its multiplicity, and its individual representatives reach very considerable sizes. Typically, the main catches are freshwater fish typical for the Volga basin. Most often caught: perch, pike perch, roach (more precisely - its varieties, called roach and ram), rudd, asp, sabrefish, bream, goldfish, carp, catfish, pike. Bersh, silver bream, white-eyed, blue bream are somewhat less common. Representatives of sturgeon (sturgeon, stellate sturgeon, beluga, etc.), salmon (nelma, brown trout - Caspian salmon) are also found in these places, but fishing is prohibited.
Northwest coast (RF)- this section covers the western coast of the Russian Federation (from the Kizlyar Bay to Makhachkala). The rivers Kuma, Terek and Sulak flow here - they carry their waters both along natural channels and artificial canals. There are bays in this area, some of which are quite large (Kizlyarsky, Agrakhansky). The sea in these places is shallow. Freshwater fish predominate in the catches: pike, perch, carp, catfish, rudd, bream, barbel, etc.
West Bank (RF)- from Makhachkala to the border of the Russian Federation with Azerbaijan. A site where mountain ranges adjoin the sea. The salinity of the water here is slightly higher than in previous places, therefore, in the catches of fishermen, marine species are more common (sea pike perch, mullet, herring). However, freshwater fish are by no means uncommon.
West Bank (Azerbaijan)- from the border of the Russian Federation with Azerbaijan along the Absheron Peninsula. Continuation of the site, where mountain ranges adjoin the sea. Fishing here is even more similar to the typical sea one, thanks to such fish as ostronos and singil (mullet) and several species of gobies, which are also caught here. In addition to them, there are kutum, herring, and some typically freshwater species, for example, the carp.
Southwest coast (Azerbaijan)- from the Absheron Peninsula to the border of Azerbaijan with Iran. Most of this site is occupied by the Kura River delta. The same fish species that were listed in the previous paragraph are caught here, but freshwater fish are more often caught.
North coast (Kazakhstan)- this section covers the northern coast of Kazakhstan. The Ural delta and the Akzhaiyk state reserve are located here, so fishing directly in the river delta and in some adjacent water area is prohibited. Fishing is possible only outside the reserve - upstream of the delta, or in the sea - at some distance from it. Fishing near the Ural delta has much in common with fishing at the confluence of the Volga - almost the same species of fish are found here.
North-east coast (Kazakhstan)- from the mouth of the Emba to Cape Tyub-Karagan. Unlike the northern part of the sea, where the water is greatly diluted by the large rivers flowing into it, its salinity somewhat increases here, so those fish species appear that avoid freshened areas, for example, sea pike perch, which is caught in the Dead Kultuk Bay. Other representatives of the marine fauna are also often found in the catches.
East coast (Kazakhstan, Turkmenistan)- from Cape Tyub-Karagan to the border of Turkmenistan and Iran. Differs in almost complete absence of flowing rivers. The salinity of the water is at its maximum here. Of the fish in these places, marine species predominate, the main catch is mullet, sea pike perch and gobies.
South Coast (Iran)- covers the southern coast of the Caspian. Along the entire length of this section, the Elburs mountain range adjoins the sea. Many rivers flow here, most of which are represented by small streams, there are also several medium and one large river. Among fish, in addition to marine species, there are also some freshwater, as well as semi-anadromous and anadromous species, for example, sturgeon.

Fishing features

At the mouths of rivers flowing in, other gear can be used, such as a float rod, feeder and traditional spinning rod.

kasparova2 majorov2006 g2gg2g-61.

Photo 8. Sunset in Aktau.

The Caspian Sea is located between Asia and Europe. It is the largest salt sea-lake located in Kazakhstan, Russia, Azerbaijan, Iran and Turkmenistan. At present, its level is 28 meters below the level of the World Ocean. The depth of the Caspian Sea is quite large. The area of the reservoir is 371 thousand square kilometers.

Story

About five million years ago, the sea split into small bodies of water, including the Black and Caspian Sea... After these events, they joined and separated. About two million years ago Caspian lake was cut off from the oceans. This period is considered the beginning of its formation. Throughout history, the reservoir has changed its contours several times, and the depth of the Caspian Sea has also changed.

Now the Caspian is the largest inland water body, containing about 44% of the planet's lake waters. Despite the ongoing changes, the depth of the Caspian Sea has not changed very much.

Once it was called the Khvali and Khazar, and the tribes of horse breeders gave it another name - the Caspian. This is the name of the tribe living on the southwestern shore of the reservoir. In total, during its existence, the lake had more than seventy names, here are some of them:

Abeskunskoe.
Derbent.
Saraiskoe.
Sihai.
Dzhurdzhanskoe.
Girkanskoe.

Depth and relief

The relief and features of the hydrological regime divide the sea-lake into northern, middle and southern parts. Over the entire area of the Caspian Sea, the average depth is 180-200 m, but the relief in different parts is different.

The northern part of the reservoir is shallow. Here the depth of the Caspian Sea-lake is approximately 25 meters. In the middle part of the Caspian there are very deep depressions, continental slopes, and shelves. Here average depth is 192 meters, and in the Derbent depression - about 788 meters.

The greatest depth of the Caspian Sea is in the South Caspian depression (1025 meters). Its bottom is flat, and there are several ridges in the northern part of the depression. It is here marked maximum depth The Caspian Sea.

Features of the coastline

Its length is seven thousand kilometers. The northern part of the coastline is lowland, the southern and western are mountains, and the eastern is highlands. The spurs of Elbrus and the Caucasus Mountains approach the shores of the sea.

The Caspian has large bays: Kazakh, Kizlyar, Mangyshlak, Kara-Bogaz-Gol, Krasnovodsky.

If you go on a cruise from north to south, the route will be 1200 kilometers long. In this direction, the reservoir has an elongated shape, and from west to east the width of the sea is different. At its narrowest point, it is 195 kilometers, and at its widest - 435 kilometers. The average width of the reservoir is 315 km.

The sea has several peninsulas: Mangyshlak, Buzachi, Miankale and others. There are also several islands here. The largest are Chygyl, Kur-Dashi, Gum, Dash, and Seal Islands.

Reservoir nutrition

About one hundred and thirty rivers flow into the Caspian. Most of them flow in the north and west. The main river flowing into the sea is the Volga. Three large rivers account for about ninety percent of the runoff: the Volga (80%), the Kura (6%) and the Ural (5%). Five percent - to Terek, Sulak and Samur, and the remaining four are brought by small rivers and streams of Iran.

Caspian resources

The reservoir has amazing beauty, a variety of ecosystems and the richest supply natural resources... When there are frosts in its northern part, magnolias and apricots bloom in the south.

The relict flora and fauna have been preserved in the Caspian Sea, including the largest flock of sturgeon fish. As it evolved, the marine flora changed more than once, adjusting to salinization and desalination. As a result, there are many freshwater species in these waters, but few marine ones.

After the Volga-Don Canal was built, new types of algae appeared in the reservoir, which were previously found in the Black and Azov seas... Now there are 854 animal species in the Caspian, of which 79 are vertebrates, and over 500 plant species. This unique sea-lake provides up to 80% of all sturgeon catch in the world and about 95% of black caviar catch.

There are five sturgeon species in the Caspian: stellate sturgeon, thorn, sterlet, beluga and sturgeon. Beluga is the largest member of the species. Its weight can reach a ton and its length is five meters. In addition to sturgeon fish, herring, salmon, kutum, roach, asp and other types of fish are caught in the sea.

Of the mammals in the Caspian Sea, only the local seal is found, which is not found in other water bodies of the world. It is considered the smallest on the planet. Its weight is about a hundred kilograms, and its length is 160 centimeters. The Caspian region is the main migration route for birds between Asia, the Middle East and Europe. Each year, approximately 12 million birds fly over the sea during their migration (in the spring to the south, and in the fall to the north). In addition, another 5 million remain in these places for wintering.

The greatest wealth of the Caspian Sea is its huge reserves of oil and gas. Geological exploration in the region has discovered large deposits of these minerals. Their potential puts the local reserves in second place in the world after