The Caspian Sea is located between Asia and Europe. This is the largest salt sea-lake, located on the territory of Kazakhstan, Russia, Azerbaijan, Iran and Turkmenistan. Currently, its level is 28 meters below the level of the World Ocean. Depth Caspian Sea big enough. The area of ​​the reservoir is 371 thousand square kilometers.

Story

About five million years ago, the sea divided into small bodies of water, including the Black and Caspian seas. After these events they united and separated. About two million years ago Caspian lake was cut off from the World Ocean. 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 body of water, containing about 44% of the planet’s lake waters. Despite the changes taking place, the depth of the Caspian Sea did not change very much.

Once it was called Khvalian and Khazar, and the tribes of horse breeders gave it another name - 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:

1. Abeskunskoe.
2. Derbent.
3. Saraiskoe.
4. Xihai.
5. Dzhurdzhanskoe.
6. Hyrcanian.

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 depth is on average 180-200 m, but the relief in different parts 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 the 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 in the northern part of the depression there are several ridges. This is where it is marked maximum depth Caspian Sea.

Coastline Features

Its length is seven thousand kilometers. Northern part coastline It is a lowland, with mountains in the south and west, and hills in the east. 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, Krasnovodsk.

If you go on a cruise from north to south, the route length will be 1200 kilometers. 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 it is 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 Tyuleni Islands.

Pond food

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

Caspian resources

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

Relict flora and fauna have been preserved in the Caspian Sea, including the largest school of sturgeon fish. As it evolves marine flora changed more than once, adapting to salinization and desalination. As a result, these waters became rich in freshwater species, but few in marine species.

After the Volga-Don Canal was built, new species of algae appeared in the reservoir, which were previously found in the Black and Seas of Azov. Now in the Caspian Sea there are 854 species of animals, of which 79 are vertebrates, and over 500 species of plants. This unique sea-lake produces up to 80% of the catch of all sturgeon in the world and approximately 95% of the black caviar production.

Five species of sturgeon are found in the Caspian Sea: stellate sturgeon, thorn, sterlet, beluga and sturgeon. Beluga is the largest representative of the species. Its weight can reach a ton, and its length can be five meters. In addition to sturgeon, 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 bodies of water in 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 a major route for bird migration between Asia, the Middle East and Europe. Every year, approximately 12 million birds fly over the sea during migration (south in spring and north in autumn). In addition, another 5 million remain in these places for the winter.

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

The Caspian Sea is the largest endorheic lake on Earth, located at the junction of Europe and Asia, called a sea due to the fact that its bed is folded earth's crust oceanic type. The Caspian Sea is an endorheic 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 approximately 1200 kilometers, from west to east - from 195 to 435 kilometers, on average 310-320 kilometers. The Caspian Sea is conventionally divided according to physical and geographical conditions into 3 parts - the Northern Caspian, the Middle Caspian and the Southern Caspian. The conditional border between the Northern and Middle Caspian runs along the line of the island. Chechen - Cape Tyub-Karagansky, between the Middle and Southern Caspian Sea - along the line of the island. Residential - Cape Gan-Gulu. The area of ​​the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

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

Bottom relief The relief of the northern part of the Caspian Sea is a shallow undulating plain with banks and accumulative islands, the average depth of the Northern Caspian Sea is 4-8 meters, the maximum does not exceed 25 meters. The Mangyshlak threshold separates the Northern Caspian from the Middle Caspian. The Middle Caspian is quite deep, the water depth in the Derbent depression reaches 788 meters. The Absheron threshold separates the Middle and Southern Caspian Seas. The Southern Caspian is considered deep-sea; the water depth in the South Caspian depression reaches 1025 meters from the surface of the Caspian Sea. Shell sands are widespread on the Caspian shelf, deep-sea areas are covered with silty sediments, and in some areas there is an outcrop of bedrock. Temperature Water temperature is subject to significant latitudinal changes, most clearly expressed in winter, when the temperature varies from 0-0.5 °C at the ice edge in the north of the sea to 10-11 °C in the south, that is, the water temperature difference is about 10 °C . For shallow water areas with depths less than 25 m, the annual amplitude can reach 25-26 °C. On average the water temperature is west coast 1-2 °C higher than in the east, and in the open sea the water temperature is 2-4 °C higher than near the coasts.

Animal and plant life The fauna of the Caspian Sea is represented by 1809 species, of which 415 are vertebrates. 101 species of fish are registered in the Caspian Sea, where most of the world's sturgeon stocks are concentrated, as well as freshwater fish such as roach, carp, and pike perch. The Caspian Sea is the habitat of fish such as carp, mullet, sprat, kutum, bream, salmon, perch, and pike. The Caspian Sea is also home to a marine mammal - the Caspian seal. The flora of the Caspian Sea and its coast is represented by 728 species. The predominant plants in the Caspian Sea are algae - blue-green, diatoms, red, brown, characeae and others, and flowering plants - zoster and ruppia. In origin, the flora is predominantly of Neogene age, but some plants were brought into the Caspian Sea by humans deliberately or on the bottoms of ships.

Minerals Many oil and gas fields are being developed in the Caspian Sea. Proven oil resources in the Caspian Sea are about 10 billion tons, total oil and gas condensate resources are estimated at 18-20 billion tons. Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf. In the second half of the 19th century, oil production began on an industrial scale on the Absheron Peninsula, and then in other territories. In addition to oil and gas production, salt, limestone, stone, sand, and clay are also mined on the coast of the Caspian Sea and the Caspian shelf.

CaspAndyskoe mOre(Caspian) is the largest enclosed body of water on Earth. In size, the Caspian Sea is much larger than lakes such as Superior, Victoria, Huron, Michigan, and Baikal. According to formal characteristics, the Caspian Sea is an endorheic lake. However, given its large size, brackish waters and a regime similar to the sea, this body of water is called a sea.

According to one hypothesis, the Caspian Sea (among the ancient Slavs – the Khvalynsk Sea) received its name in honor of the Caspian tribes who lived BC 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; average width – 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 Caucasus Mountains approach the sea, in the south the Elburz ridge stretches near the coast.

The surface of the Caspian Sea is located significantly below the level of the World Ocean. Its current level fluctuates around -27...-28 m. These levels correspond to a sea surface area of ​​390 and 380 thousand km 2 (without the Kara-Bogaz-Gol Bay), a water volume of 74.15 and 73.75 thousand km 3, average depth approximately 190 m.

The Caspian Sea is traditionally divided into three large parts: the Northern (24% of the sea area), the Middle (36%) and the Southern 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, the volume is less than 1% of the total water mass of the sea. The Middle Caspian is an isolated basin with an 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 sea's water mass is concentrated here.

There are about 50 islands in the Caspian Sea with total area approximately 400 km 2; 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 rugged. Here are the large bays of Kizlyarsky, Komsomolets, Mangyshlaksky, Kazakhsky, Kara-Bogaz-Gol, Krasnovodsky and Turkmensky, many bays; off the west coast - Kyzylagachsky. The largest peninsulas are Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak, Krasnovodsky, Cheleken and Apsheronsky. The most common shores are accumulative; areas with abrasion shores are found along the contour of the Middle and Southern Caspian Sea.

Over 130 rivers flow into the Caspian Sea, the largest of which are the Volga , Ural, Terek, Sulak, Samur, Kura, Sefidrud, Atrek, Emba (its flow 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 an endorheic 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 and coastal zones. In the Caspian Sea level varied in the range of ~200 m: from -140 to +50 m BS; at -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 level 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 in level has been dominant - to -27.69 m BS in 2013.

During major north shore The Caspian Sea shifted to Samara Luka on the Volga, and maybe further. During maximum transgressions, the Caspian Sea turned into a drainage lake: excess water flowed through the Kuma-Manych depression into the Sea of ​​Azov and further into the Black Sea. In extreme regressions South coast The Caspian Sea shifted to the Absheron threshold.

Long-term fluctuations in the level of the Caspian Sea are explained by changes in the structure of the water balance of the Caspian Sea. Sea level rises when the incoming part of the water balance (primarily the water flow of rivers) increases and exceeds the outgoing part, and decreases if the inflow river waters is shrinking. The total water flow of all rivers averages 300 km 3 /year; while the five largest rivers account for almost 95% (the Volga gives 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 was the Volga runoff), precipitation - 70.9, underground flow - 4 km 3 /year, and evaporation and outflow into the Kara-Bogaz-Gol Bay are 354.79 and 9.8 km 3 /year. During the period of intense 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.

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 level fluctuations occur 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 edge “retreat” by several tens kilometers inland, and during surges it will 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, there is strong excitement in the Caspian Sea. The highest wave heights in the Southern Caspian Sea can reach 10–11 m. Wave heights decrease in the direction from south to north. Storm waves can develop at any time of the year, but they are more frequent and more dangerous in the cold half of the year.

In the Caspian Sea as a whole, wind currents predominate; Nevertheless, in the estuary coastal zones of large rivers, runoff currents play a significant role. In the Middle Caspian, cyclonic water circulation predominates, in the Southern Caspian - anticyclonic. In the northern part of the sea, patterns of wind currents are more irregular and depend on the characteristics and variability of the wind, bottom topography and coastal contours, river flow and aquatic vegetation.

Water temperature is subject to significant latitude 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 Sea it can reach 35–40 o C. At depths, a constant temperature is maintained: deeper than 100 m it is 4–7 o C.

It only freezes in winter Northern part Caspian Sea; in severe winter - the entire Northern Caspian and coastal zones of the Middle Caspian. Freeze-up in the Northern Caspian lasts from November to March.

Water salinity changes especially sharply in the northern part of the sea: from 0.1‰ at the mouth shores of the Volga and Ural to 10–12‰ on the border with the Middle Caspian. In the Northern Caspian Sea, the temporal variability of water salinity is also great. In the middle and southern parts of the sea, salinity fluctuations are small: it is generally 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. The fish species are goby, herring, salmon, carp, mullet and sturgeon. The latter include five species: sturgeon, beluga, stellate sturgeon, thorn and sterlet. The sea can produce 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. 5–6 million waterfowl migrate through the Caspian region annually.

The economy of the Caspian Sea is associated with oil and gas production, shipping, fishing, seafood, various salts and minerals (Kara-Bogaz-Gol Bay), using recreational resources. The explored oil resources in the Caspian Sea amount to about 10 billion tons, the total resources of oil and gas condensate are estimated at 18–20 billion tons. Oil and gas production is carried out on an ever-increasing scale. The Caspian Sea is used and 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), Noushehr, Bandar-Anzeli, Bandar-Torkemen (Iran) and Turkmenbashi (Turkmenistan).

Economic activities and hydrological features The Caspian Sea creates a number of serious environmental and water management problems. Among them: anthropogenic pollution of river and sea ​​waters(mainly petroleum products, phenols and surfactants), poaching and reduction of fish stocks, especially sturgeon; 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 dangerous hydrological phenomena and hydrological-morphological processes.

The total economic damage for all 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, and the destruction of coastlines and coastal structures, amounted to an estimated amount of 15 to 30 billion US dollars. Urgent engineering measures were required to protect the coast.

A sharp drop in the level of the Caspian Sea in the 1930s–1970s. resulted in less damage, but it was still significant. Navigable approach channels became shallow, the shallow seaside at the mouths of the Volga and Ural became heavily overgrown, which became an obstacle to the passage of fish into the rivers to spawn. Fish passages had to be built through the mentioned seashores.

Among the unresolved problems is the lack of an international agreement on the international legal status of the Caspian Sea, the division of its waters, bottom and subsoil.

The Caspian Sea is the object of many years of research by specialists from all 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 the Moscow State University took an active part in the study of the Caspian Sea. state university and etc.

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

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

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

Map of the Caspian Sea

The Caspian Sea washes the shores of five coastal states:

Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, 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, coastline length - 724 kilometers
Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

Water temperature

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

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

Animal world

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

Vegetable world

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

Mining of oil and gas

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

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

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

Ecological problems

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

The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The Caspian Sea is shaped like 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 conventionally divided according to physical and geographical conditions into 3 parts - the Northern Caspian, the Middle Caspian and the Southern Caspian. The conditional border between the Northern and Middle Caspian Seas passes along the Chechen line (island)- Tyub-Karagansky Cape, between the Middle and Southern Caspian Seas - along the Zhiloi line (island)- Gan-Gulu (Cape). The area of ​​the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

According to one hypothesis, the Caspian Sea received its name in honor of the ancient tribes of horse breeders - the Caspians, who lived BC on the southwestern coast of the Caspian Sea. Throughout the history of its existence, the Caspian Sea had about 70 names among 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 (Darya-e Khazar), Turkish and Azerbaijani (Khazar denizi) languages; Abeskun Sea; Sarayskoye Sea; Derbent Sea; Sihai and other names. In Iran, the Caspian Sea is still called the Khazar or Mazandaran Sea. (after the name of the people inhabiting the coastal province of Iran of the same name).

The coastline of the Caspian Sea is estimated at approximately 6,500 - 6,700 kilometers, with islands - up to 7,000 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 banks are low and swampy, and the water surface in many places is covered with thickets. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of ​​the Absheron Peninsula and on the eastern coast in the area of ​​the Kazakh Gulf and Kara-Bogaz-Gol.

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. Most large islands: Ashur-Ada, Garasu, Gum, Dash, Zira (island), Zyanbil, Kur Dashi, Khara-Zira, Sengi-Mugan, Chechen (island), Chygyl.

Large bays of the Caspian Sea: Agrakhansky Bay, Komsomolets (bay) (formerly Dead Kultuk, formerly Tsesarevich Bay), Kaydak, Mangyshlak, Kazakh (bay), Turkmenbashi (bay) (formerly Krasnovodsk), Turkmen (bay), Gizilagach, Astrakhan (bay), Gyzlar, Girkan (formerly Astarabad) and Anzeli (formerly Pahlavi).

Off the east coast is salt Lake Kara Bogaz Gol, 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, and 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 flows from the Caspian Sea to Kara-Bogaz-Gol and evaporates there. Every year, 8 - 10 cubic kilometers of water flow from the Caspian Sea to Kara-Bogaz-Gol (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 delta-shaped mouth. Large rivers flowing into the Caspian Sea - Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (Russian border with Azerbaijan), Atrek (Turkmenistan) and others. Largest river, flowing into the Caspian Sea - the Volga, its average annual flow is 215-224 cubic kilometers. The Volga, Ural, Terek and Emba provide up to 88 - 90% of the annual runoff 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 basin area. The length of the Caspian Sea basin from north to south is about 2500 kilometers, from west to east - about 1000 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 trap and north-west, 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, coastline length - 724 kilometers
• Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

The largest city and port on the Caspian Sea is Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and has a population of 2,070 thousand people. (2003) . Other large Azerbaijani Caspian cities are Sumgait, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near southern border Azerbaijan. To the South-East of the Absheron Peninsula, the oil workers’ village of Neftyanye Kamni is located, the buildings of which stand on artificial islands, overpasses and technological sites.

Large Russian cities- the capital of Dagestan Makhachkala and the most Southern City Russia Derbent - 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 north coast Caspian Sea.

On east coast On 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, former Krasnovodsk. Several Caspian cities are located in the southern (Iranian) coast, the largest of them is Anzeli.

The area and volume of water of 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 Lake 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 been 15 meters. Instrumental measurements of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during which time the highest water level was recorded in 1882 (-25.2 m.), lowest - in 1977 (-29.0 m.), since 1978 the water level has risen and in 1995 reached −26.7 m; since 1996, a downward trend has emerged again. Scientists associate the reasons for changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.

Water temperature is subject to significant latitudinal changes, most clearly expressed in winter, when the temperature varies from 0 - 0.5 °C at the ice edge in the north of the sea to 10 - 11 °C in the south, that is, the difference in water temperature is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average, the water temperature off the west coast is 1 - 2 °C higher than that on the east, and in the open sea the water temperature is 2 - 4 °C higher than on the coasts. Based on the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time periods can be distinguished in the upper 2-meter layer. From October to March, the water temperature increases in the southern and eastern regions, which is especially clearly visible in the Middle Caspian. Two stable quasi-latitudinal zones can be distinguished, where temperature gradients are increased. This is, firstly, the border between the Northern and Middle Caspian, and, secondly, between the Middle and Southern. 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 Absheron threshold, from 7 to 10 °C. During this period, the least cooled waters are in the center of the South Caspian Sea, which form a quasi-stationary core. In April-May, the area of ​​minimum temperatures moves to the Middle Caspian Sea, which is associated with faster heating 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 number of heat is spent on melting the ice, but already in May the temperature here rises to 16 - 17 °C. In the middle part the temperature at this time is 13 - 15 °C, and in the south it increases to 17 - 18 °C. Spring warming of water evens out horizontal gradients, and the temperature difference between coastal areas and open sea does not exceed 0.5 °C. Warming of the surface layer, which begins in March, disrupts the uniformity of temperature distribution with depth. In June-September, horizontal uniformity in the temperature distribution in the surface layer is observed. In August, which is the month of 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 Southern Caspian. The rise of cold deep waters occurs with varying intensity as a result of the influence of prevailing summer season northwest winds. The wind in this direction causes the outflow of warm surface waters from the coast and the rise of colder waters from the intermediate layers. Upwelling begins in June, but it reaches its greatest intensity in July-August. As a result, a decrease in temperature is observed on the water surface (7 - 15 °C). Horizontal temperature gradients reach 2.3 °C on the surface and 4.2 °C at a depth of 20 m. The source of upwelling gradually shifts from 41 - 42° N. 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 open areas of the sea, at the end of May - beginning of June, the formation of a temperature jump layer begins, which is most clearly expressed in August. Most often it is located between 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 off the eastern coast, the shock layer rises close to the surface. Since the Caspian Sea lacks a stable baroclinic layer with large supply potential energy similar to the main thermocline of the World Ocean, then with the cessation of the prevailing winds causing upwelling and with the beginning of autumn-winter convection in October-November, a rapid restructuring of the temperature fields to the winter regime occurs. 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 eroded due to convective mixing and disappears by the end of November.

The salt composition of the waters of the closed Caspian Sea differs from the oceanic one. There are significant differences in the ratios of concentrations of salt-forming ions, especially for waters in areas directly influenced by continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total amount of salts of sea waters, an increase in the relative amount of carbonates, sulfates, calcium, which are the main components in chemical composition river waters. The most conservative ions are potassium, sodium, chlorine and magnesium. The least conservative are calcium and bicarbonate ions. In the Caspian Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of ​​Azov, and the sulfate anion is three times higher. Water salinity changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and Ural up to 10 - 11 units. psu on the border with the Middle Caspian. Mineralization in shallow salty bays-kultuks can reach 60 - 100 g/kg. In the Northern Caspian, during the entire ice-free period from April to November, a salinity front of a quasi-latitudinal location is observed. The greatest desalination, associated with the spread of river flow across the sea, is observed in June. The formation of the salinity field in the Northern Caspian Sea 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 (by 0.1 - 0.2 psu units). In the deep-sea part of the Caspian Sea, in the vertical profile of salinity, characteristic deflections of isohalines and local extrema are observed in the area of ​​the eastern continental slope, which indicate the processes of bottom sliding of waters salinizing in the eastern shallow waters of the South Caspian. The salinity value also strongly depends on sea level and (which is related) on the volume of continental runoff.

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

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

The average annual precipitation is 200 millimeters per year, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters along the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea is about 1000 millimeters per year, the most intense evaporation in the area of ​​the Absheron Peninsula and in the eastern part of the South Caspian Sea is up to 1400 millimeters per year.

Winds often blow on the territory of the Caspian Sea, their average annual speed is 3-7 meters per second, the wind rose is dominated by north winds. In the autumn and winter months, winds become stronger, with wind speeds often reaching 35-40 meters per second. The most windy territories are the Absheron Peninsula and the environs of Makhachkala - Derbent, where the most high wave- 11 meters.

Water circulation in the Caspian Sea is related to runoff and winds. Because the most of The drainage falls on the Northern Caspian Sea, northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current divides into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.

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, where most of the world's sturgeon reserves are concentrated, as well as freshwater fish such as roach, carp, and pike perch. The Caspian Sea is the habitat of fish such as carp, mullet, sprat, kutum, bream, salmon, perch, and pike. The Caspian Sea is also home to 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. Among the plants in the Caspian Sea, the predominant algae are blue-green, diatoms, red, brown, characeae and others, and among the flowering plants - zoster and ruppia. In origin, the flora is predominantly of Neogene age, but some plants were brought into the Caspian Sea by humans deliberately or on the bottoms of ships.