The Caspian Sea is salty or freshwater. Caspian lake. Why is the Caspian Lake called a sea? Water level fluctuations

The Caspian Sea is located in different geographical areas. It plays a large role in world history and is an important economic region and source of resources. The Caspian Sea is a unique body of water.

Short description

This sea is large. The bottom is covered with oceanic crust. These factors allow us to classify it as a sea.

It is a closed body of water, has no drains and is not connected to the waters of the World Ocean. Therefore, it can also be classified as a lake. In this case, it will be the largest lake on the planet.

The approximate area of the Caspian Sea is about 370 thousand square kilometers. The volume of the sea changes depending on various fluctuations in water level. The average value is 80 thousand cubic kilometers. The depth varies in its parts: the southern one has greater depth than the northern one. The average depth is 208 meters, the greatest value in the southern part exceeds 1000 meters.

The Caspian Sea plays a major role in the development of trade relations between countries. The resources mined there, as well as other trade items, were transported to different countries since the development of maritime navigation. Since the Middle Ages, merchants have brought exotic goods, spices and furs. Today, in addition to transporting resources, transport is carried out by sea ferry crossings between cities. The Caspian Sea is also connected by a shipping canal through rivers with Sea of Azov.

Geographical characteristics

The Caspian Sea is located between two continents - Europe and Asia. It washes the territory of several countries. These are Russia, Kazakhstan, Iran, Turkmenistan and Azerbaijan.

It has more than 50 islands, both large and small in area. For example, the islands of Ashur-Ada, Tyuleniy, Chigil, Gum, Zenbil. And also the peninsulas, the most significant - Absheronsky, Mangyshlak, Agrakhansky and others.

Main influx water resources The Caspian Sea receives its water from the rivers flowing into it. There are a total of 130 tributaries of this reservoir. The largest is the Volga River, which brings the bulk of water. The rivers Heras, Ural, Terek, Astarchay, Kura, Sulak and many others also flow into it.

The waters of this sea form many bays. Among the largest: Agrakhansky, Kizlyarsky, Turkmenbashi, Hyrkan Bay. In the eastern part there is a bay-lake called Kara-Bogaz-Gol. It communicates with the sea through a small strait.

Climate

The climate is characterized geographical location sea, therefore it has several types: from continental in the northern region to subtropical in the southern. This affects air and water temperatures, which have large contrasts depending on the part of the sea, especially in the cold season.

in winter average temperature air in the northern region is about -10 degrees, water reaches a value of -1 degree.

In the southern region, air and water temperatures in winter warm up to an average of +10 degrees.

IN summer time The air temperature in the northern zone reaches +25 degrees. It's much hotter in the south. The maximum recorded value here is + 44 degrees.

Resources

The natural resources of the Caspian Sea contain large reserves of various deposits.

One of the most valuable resources of the Caspian Sea is oil. Mining has been carried out since approximately 1820. The springs opened on the territory of the seabed and its coast. Already by the beginning of the new century, the Caspian Sea occupied a leading position in obtaining this valuable product. During this time, thousands of wells were opened, which made it possible to extract oil on a huge industrial scale.

The Caspian Sea and its surrounding area also have rich deposits of natural gas, mineral salts, sand, lime, several types of natural clay and rocks.

Inhabitants and fisheries

The biological resources of the Caspian Sea are distinguished by great diversity and good productivity. It contains more than 1,500 species of inhabitants and is rich in commercial fish species. Occupancy depends on climatic conditions in different parts of the sea.

In the northern part of the sea, pike perch, bream, catfish, asp, pike and other species are more common. The western and eastern areas are inhabited by gobies, mullet, bream, and herring. Southern waters are rich in different representatives. One of the many is sturgeon. In terms of their content, this sea occupies a leading place among other bodies of water.

Among the wide variety, tuna, beluga, stellate sturgeon, sprat and many others are also caught. In addition, there are mollusks, crayfish, echinoderms and jellyfish.

The Caspian seal is a mammal that lives in the Caspian Sea, or this animal is unique and lives only in these waters.

The sea is also characterized by a high content of various algae, for example, blue-green, red, brown; sea grass and phytoplankton.

Ecology

Oil production and transportation have a huge negative impact on the ecological situation of the sea. Oil products getting into water is almost inevitable. Oil stains cause irreparable damage to marine habitats.

The main influx of water resources to the Caspian Sea comes from rivers. Unfortunately, most of them have high level pollution, which deteriorates the quality of sea water.

Industrial and domestic wastewater from surrounding cities in huge quantities drain into the sea, which also causes environmental damage.

Poaching causes great damage to marine habitats. The main target for illegal fishing is sturgeon species. This significantly reduces the number of sturgeon and threatens the entire population of this type.

The information provided will help to assess the resources of the Caspian Sea and briefly study the characteristics and ecological situation of this unique body of water.

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 water streams and the 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.

Peninsulas of the Caspian Sea

Large peninsulas of the Caspian Sea:
* Agrakhan Peninsula
* Absheron Peninsula, located on the western coast of the Caspian Sea in the territory of Azerbaijan, at the northeastern end Greater Caucasus, on its territory the cities of Baku and Sumgayit are located
* Buzachi
* Mangyshlak, located on the eastern coast of the Caspian Sea, on the territory of Kazakhstan, on its territory is the city of Aktau.
* Miankale
* Tub-Karagan

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

Most large islands:

* Ashur-Ada
* Garasu
*Hum
* Dash
* Zira (island)
* Zyanbil
* Cure Dasha
* Khara-Zira
* Sengi-Mugan
* Chechen (island)
* Chygyl

Large bays of the Caspian Sea:

* Agrakhan Bay,
* Komsomolets (bay),
* Mangyshlak,
* Kazakh (bay),
* Turkmenbashi (bay) (formerly Krasnovodsk),
* Turkmen (bay),
* Gizilagach,
* Astrakhan (bay)
* Gyzlar
* Hyrcanus (formerly Astarabad) and
* Anzeli (formerly Pahlavi).

Rivers flowing into the Caspian Sea

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

Basin 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.

Coastal states

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, coastline length 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, coastline length 955 kilometers

Cities on the Caspian Sea coast

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 major Azerbaijani Caspian cities are Sumgait, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the South-East of the Absheron Peninsula, 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. port city Astrakhan is also considered to be part 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 on the southern (Iranian) coast, the largest of them is Anzeli.

Area, depth, volume of water

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 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 in Northern part The Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

Water level fluctuations

The water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past 3 thousand years the amplitude of changes in the water level of the Caspian Sea has amounted to 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), the lowest in 1977 (-29.0 m) , since 1978, the water level has risen and in 1995 reached −26.7 m; since 1996, there has again been a downward trend in the level of the Caspian Sea. Scientists associate the reasons for changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.

Water temperature

Water temperature is subject to significant latitudinal changes, most clearly expressed in winter period when the temperature changes from 0-0.5 °C at the ice edge in the north of the sea to 10-11 °C in the south, that is, the water temperature difference is about 10 °C. For shallow areas with depths less than 25 m, the annual amplitude can reach 25-26 °C. On average, the water temperature off the western coast is 1-2 °C higher than that on the eastern coast, 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 can be distinguished: time intervals in the upper 2-meter layer. From October to March, the water temperature increases in the southern and eastern regions, which is especially noticeable 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 amount of heat is spent on melting 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 up of the surface layer, starting in March, disrupts the homogeneity in the temperature distribution with depth. In June-September, horizontal homogeneity 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 northwestern winds prevailing in the summer season. 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 surface of the water (7-15 °C). Horizontal temperature gradients reach 2.3 °C at the surface and 4.2 °C at a depth of 20 m.

The source of upwelling gradually shifts from 41-42° north. latitude in June, to 43-45° north. latitude 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, in late May - early June, the formation of a temperature jump layer begins, which is most clearly expressed in August. Most often it is located between 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 in the Caspian Sea there is no stable baroclinic layer with a large reserve of 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 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.

Water composition

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. On the formation of the salinity field in the Northern Caspian Sea big influence exerts a wind field. In the middle and southern parts sea salinity fluctuations are small. Basically it is 11.2-12.8 units. psu, increasing in the southern and eastern directions. With depth, salinity increases slightly (by 0.1-0.2 units psu).

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 processes of bottom sliding of waters salinizing in the eastern shallow waters of the South Caspian. The magnitude of salinity also strongly depends on sea level and (which is interconnected) on the volume of continental runoff.

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 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.

Climate

The climate of the Caspian Sea is continental in the northern part, temperate in the middle part and subtropical in the southern part. In winter, the average monthly temperature of the Caspian Sea varies from −8 −10 in the northern part to +8-10 in the southern part, in summer period- 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 areas are the Absheron Peninsula and the environs of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.

Currents

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

Animal world

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 world, where most of the world's sturgeon reserves are concentrated, as well as such freshwater fish 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.

Vegetable world

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

Origin of the Caspian Sea

The Caspian Sea is of oceanic origin - its bed is composed of oceanic-type crust. It was formed approximately 10 million years ago, when the closed Sarmatian Sea, which lost contact with the world's oceans approximately 70 million years ago, was divided into two parts - the "Caspian Sea" and the Black Sea.

Anthropological and cultural history Caspian Sea

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

Research of the Caspian Sea

Research of the Caspian Sea was started by Peter the Great, when, on his order, an expedition was organized in 1714-1715 under the leadership of A. Bekovich-Cherkassky. In the 1820s, hydrographic research was continued by I. F. Soyomov, and later by I. V. Tokmachev, M. I. Voinovich and other researchers. At the beginning of the 19th century, instrumental surveys of the shores were carried out by I. F. Kolodkin, in the mid-19th century. - instrumental geographical survey under the direction of N. A. Ivashintsev. Since 1866, for more than 50 years, expeditionary research on the hydrology and hydrobiology of the Caspian Sea was carried out under the leadership of N. M. Knipovich. In 1897, the Astrakhan Research Station was founded. In the first decades of Soviet power, geological research by I.M. Gubkin and other Soviet geologists was actively carried out in the Caspian Sea, mainly aimed at searching for oil, as well as research into the water balance and level fluctuations of the Caspian Sea.

Mining of oil and gas

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

Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf. 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.

Shipping

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

Fishing and seafood production

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

Recreational resources

Natural environment of the Caspian coast with sandy beaches, mineral waters And therapeutic mud in the coastal zone creates good conditions for rest and treatment. At the same time, according to the degree of development of resorts and the tourism industry Caspian coast loses noticeably Black Sea coast Caucasus. At the same time, in last years The tourism industry is actively developing on the coasts of Azerbaijan, Iran, Turkmenistan and Russian Dagestan.

Ecological problems

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

Border dispute over the status of the Caspian Sea

After the collapse of the USSR, the division of the Caspian Sea has long been and still remains the subject of unresolved disagreements related to the division of Caspian shelf resources - oil and gas, as well as biological resources. For a long time, negotiations were ongoing between the Caspian states on the status of the Caspian Sea - Azerbaijan, Kazakhstan and Turkmenistan insisted on dividing the Caspian along the median line, Iran insisted on dividing the Caspian by one-fifth between all Caspian states. In 2003, Russia, Azerbaijan and Kazakhstan signed an agreement on the partial division of the Caspian Sea along the median line.

Coordinates: 42.622596 50.041848

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 Zhilaya 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 southwest coast Caspian Sea. Throughout the history of its existence, the Caspian Sea had about 70 names among different tribes and peoples: 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. The largest 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. The largest river flowing into the Caspian Sea is 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 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 major Azerbaijani Caspian cities are Sumgait, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the South-East of the Absheron Peninsula, the oil workers’ settlement Neftyanye Kamni is located, the structures of which are located on artificial islands, overpasses and technological sites.

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

On the eastern shore of the Caspian Sea there is a Kazakh city - the port of Aktau, in the north in the Ural delta, 20 km from the sea, the city of Atyrau is located, south of Kara-Bogaz-Gol on the northern shore of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, 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 amounted to 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 noticeable 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 amount of heat is spent on melting 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 the open sea does not exceed 0.5 °C. The heating 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 northwestern winds prevailing in the summer season. 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 upwelling center 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 in the Caspian Sea there is no stable baroclinic layer with a large reserve of 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 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 the chemical composition of river waters. The most conservative ions are potassium, sodium, chlorine and magnesium. The least conservative are calcium and bicarbonate ions. In the Caspian Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of Azov, and the sulfate anion is three times higher. 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 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 part and subtropical in the southern part. In winter, the average monthly temperature of the Caspian Sea varies from −8 −10 in the northern part to +8 - +10 in the southern part, in summer - from +24 - +25 in the northern part to +26 - +27 in the southern part. The maximum temperature recorded on the east coast was 44 degrees.

On the territory of the Caspian Sea, winds often blow, their average annual speed is 3-7 meters per second, and northern winds predominate in the wind rose. In the autumn and winter months, winds become stronger, with wind speeds often reaching 35-40 meters per second. The most windy areas are the Absheron Peninsula and the environs of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.

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 such freshwater fish 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 Caspian Sea is the most big lake of our planet, which is located in a depression of the earth’s surface (the so-called Aral-Caspian Lowland) on the territory of Russia, Turkmenistan, Kazakhstan, Azerbaijan and Iran. Although they consider it as a lake, because it is not connected with the World Ocean, but by the nature of the formation processes and history of origin, by its size, the Caspian Sea is a sea.

The area of the Caspian Sea is about 371 thousand km 2. The sea, stretching from north to south, has a length of about 1200 km and an average width of 320 km. The length of the coastline is about 7 thousand km. The Caspian Sea is located 28.5 m below the level of the World Ocean and its greatest depth is 1025 m. There are about 50 islands in the Caspian Sea, mostly small in area. The large islands include such islands as Tyuleniy, Kulaly, Zhiloy, Chechen, Artem, Ogurchinsky. There are also many bays in the sea, for example: Kizlyarsky, Komsomolets, Kazakhsky, Agrakhansky, etc.

The Caspian Sea is fed by more than 130 rivers. The largest amount of water (about 88% of the total flow) is brought by the rivers Ural, Volga, Terek, Emba, which flow into the northern part of the sea. About 7% of the runoff comes from large rivers Kura, Samur, Sulak and small ones flowing into the sea on the west coast. The rivers Heraz, Gorgan, and Sefidrud flow into the southern Iranian coast, bringing only 5% of the flow. IN eastern part Not a single river flows into the sea. The water in the Caspian Sea is salty, its salinity ranges from 0.3‰ to 13‰.

Shores of the Caspian Sea

The shores have different landscapes. The shores of the northern part of the sea are low and flat, surrounded by low-lying semi-desert and somewhat elevated desert. In the south, the shores are partly low-lying, bordered by the coastal lowland small area, behind which the Elburz ridge runs along the coast, which in some places comes close to the coast. In the west, the Greater Caucasus ranges approach the coast. In the east there is an abrasion coast, carved out of limestone, and semi-desert and desert plateaus approach it. The coastline changes greatly due to periodic fluctuations in water levels.

The climate of the Caspian Sea is different:

Continental in the north;

Moderate in the middle

Subtropical in the south.

At the same time, there are severe frosts and snowstorms on the northern shore, while fruit trees and magnolias bloom on the southern shore. In winter, strong storm winds rage at sea.

On the coast of the Caspian Sea there are big cities, ports: Baku, Lankaran, Turkmenbashi, Lagan, Makhachkala, Kaspiysk, Izberbash, Astrakhan, etc.

The fauna of the Caspian Sea is represented by 1809 species of animals. More than 70 species of fish are found in the sea, including: herring, gobies, stellate sturgeon, sturgeon, beluga, white fish, sterlet, pike perch, carp, bream, roach, etc. Of the marine mammals, only the smallest in the world, the Caspian seal, is found in the lake. not found in other seas. The Caspian Sea lies on the main migratory route of birds between Asia, Europe and the Middle East. Every year, about 12 million birds fly over the Caspian Sea during migration, and another 5 million usually winter here.

Vegetable world

The flora of the Caspian Sea and its coast includes 728 species. Basically, the sea is inhabited by algae: diatoms, blue-greens, red, characeae, brown and others, of the flowering ones - rupee and zoster.

The Caspian Sea is rich in reserves natural resources, many oil and gas fields are being developed in it, in addition, limestone, salt, sand, stone and clay are also mined here. The Caspian Sea is connected by the Volga-Don Canal with the Sea of Azov, and shipping is well developed. A lot is caught in the reservoir different fish, including more than 90% of the world's sturgeon catch.

The Caspian Sea is also a recreation area; on its shores there are holiday homes, tourist centers and sanatoriums.

Related materials:

The Caspian Sea is remarkable in that its western shore belongs to Europe, and its eastern shore is located in Asia. This is a huge body of salt water. It is called a sea, but, in fact, it is a lake, since it has no connection with the World Ocean. Therefore, it can be considered the most large lake in the world.

The area of the water giant is 371 thousand square meters. km. As for the depth, the northern part of the sea is quite shallow, and the southern part is deep. The average depth is 208 meters, but it does not give any idea of the thickness of the water mass. The entire reservoir is divided into three parts. These are the Northern, Middle and Southern Caspian. The northern one is a sea shelf. It accounts for only 1% of the total volume of water. This part ends behind the Kizlyar Bay near the island of Chechen. The average depth in these places is 5-6 meters.

In the Middle Caspian, the seabed noticeably decreases, and the average depth reaches 190 meters. The maximum is 788 meters. This part of the sea contains 33% of the total volume of water. And the South Caspian is considered the deepest. It absorbs 66% of the total water mass. The maximum depth is noted in the South Caspian depression. She is equal 1025 meters and is considered the official maximum depth of the sea today. The Middle and Southern Caspian Seas are approximately equal in area and occupy a total of 75% of the area of the entire reservoir.

The maximum length is 1030 km, and the corresponding width is 435 km. The minimum width is 195 km. The average figure corresponds to 317 km. That is, the reservoir has an impressive size and is rightfully called a sea. The length of the coastline together with the islands reaches almost 7 thousand km. As for the water level, it is 28 meters below the level of the World Ocean.

The most interesting thing is that the level of the Caspian Sea is subject to cyclicity. The water rises and falls. Water level measurements have been carried out since 1837. According to experts, over the last thousand years the level has fluctuated within 15 meters. This is a very large number. And they associate it with geological and anthropogenic (human impact on the environment) processes. However, it has been noted that since the beginning of the 21st century, the level of the huge reservoir has been steadily rising.

The Caspian Sea is surrounded by 5 countries. These are Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. And the longest coastline Kazakhstan has. Russia is in 2nd place. But the length of the coastline of Azerbaijan reaches only 800 km, but in this place there is the most major port in the Caspian Sea. This is, of course, Baku. The city is home to 2 million people, and the population of the entire Absheron Peninsula is 2.5 million people.

"Oil Rocks" - a city in the sea
These are 200 platforms with total length 350 kilometers

Notable is the oil workers' village, which is called " Oil Rocks". It is located 42 km east of Absheron in the sea and is a creation of human hands. All residential and industrial buildings are built on metal overpasses. People service drilling rigs that pump oil from the bowels of the earth. Naturally, there are no permanent residents in this village.

In addition to Baku, there are other large cities along the shores of the salty reservoir. At the southern tip is the Iranian city of Anzali with a population of 111 thousand people. This is the largest Iranian port on the Caspian Sea. Kazakhstan owns the city of Aktau with a population of 178 thousand people. And in the northern part, directly on the Ural River, is the city of Atyrau. It is inhabited by 183 thousand people.

The Russian city of Astrakhan also has the status of a seaside city, although it is 60 km from the coast and is located in the Volga River delta. This is a regional center with a population of more than 500 thousand people. Directly on the seashore there are such Russian cities as Makhachkala, Kaspiysk, Derbent. The latter refers to ancient cities peace. People have been living in this place for more than 5 thousand years.

Many rivers flow into the Caspian Sea. There are about 130 of them. The largest of them are the Volga, Terek, Ural, Kura, Atrek, Emba, Sulak. It is rivers, not precipitation, that feed the huge reservoir. They give him up to 95% of water per year. The basin of the reservoir is 3.626 million square meters. km. These are all rivers with their tributaries flowing into the Caspian Sea. The territory is huge, it includes Kara-Bogaz-Gol Bay.

It would be more correct to call this bay a lagoon. It means a shallow body of water separated from the sea by a sandbar or reefs. There is such a spit in the Caspian Sea. And the strait through which water flows from the sea is 200 km wide. True, people, with their restless and ill-considered activities, almost destroyed Kara-Bogaz-Gol. They fenced off the lagoon with a dam, and its level dropped sharply. But after 12 years the mistake was corrected and the strait was restored.

The Caspian Sea has always been shipping is developed. In the Middle Ages, merchants brought exotic spices and snow leopard skins from Persia to Rus' by sea. Nowadays, the reservoir connects the cities located on its banks. Ferry crossings are practiced. There is a water connection with the Black and Baltic Sea through rivers and canals.

Caspian Sea on the map

The body of water is also important from the point of view fisheries, because sturgeon live in large numbers there and provide caviar. But today the number of sturgeon has decreased significantly. Environmentalists propose to ban the fishing of this valuable fish until the population recovers. But this issue has not yet been resolved. The number of tuna, bream, and pike perch also decreased. Here you need to take into account the fact that poaching is highly developed at sea. The reason for it is heavy economic situation region.

And, of course, I need to say a few words about oil. The extraction of “black gold” at sea began in 1873. The areas adjacent to Baku have become a real gold mine. There were more than 2 thousand wells here, and oil production and refining was carried out on an industrial scale. At the beginning of the 20th century it was the center of the international oil industry. In 1920, Azerbaijan was captured by the Bolsheviks. Oil wells and factories were requisitioned. The entire oil industry came under the control of the USSR. In 1941, Azerbaijan supplied 72% of all oil produced in the socialist state.

In 1994, the “Contract of the Century” was signed. He started international development Baku oil fields. The main Baku-Tbilisi-Ceyhan pipeline allows Azerbaijani oil to flow directly to the Mediterranean port of Ceyhan. It was put into operation in 2006. Today, oil reserves are estimated at 12 trillion. US dollars.

Thus, it is clear that the Caspian Sea is one of the most important economic regions of the world. The political situation in the Caspian region is quite complicated. For a long time there have been debates about maritime borders between Azerbaijan, Turkmenistan and Iran. There were many inconsistencies and disagreements, which negatively affected the development of the region.

This came to an end on August 12, 2018. On this day, the states of the “Caspian Five” signed the Convention on the Legal Status of the Caspian Sea. This document delimited the bottom and subsoil, and each of the five countries (Russia, Kazakhstan, Iran, Turkmenistan, Azerbaijan) received its share in the Caspian basin. Rules for navigation, fishing, scientific research, and pipeline laying were also approved. The boundaries of territorial waters received state status.

Yuri Syromyatnikov

It might be useful to read: