Like the Caspian Sea. Interesting facts about the Caspian Sea: depth, relief, coastline, resources

18.10.2021

, Kazakhstan, Turkmenistan, Iran, Azerbaijan

Geographical position

Caspian Sea - view from space.

The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The length of the Caspian Sea from north to south is about 1200 kilometers (36 ° 34 "-47 ° 13" N), from west to east - from 195 to 435 kilometers, on average 310-320 kilometers (46 ° -56 ° c. d.).

The Caspian Sea is conventionally divided by physical and geographical conditions into 3 parts - the North Caspian, the Middle Caspian and the South Caspian. The conditional border between the North and Middle Caspian runs along the line about. Chechnya - Cape Tyub-Karagan, between the Middle and South Caspian - along the line of about. Residential - Cape Gan-Gulu. The area of the North, Middle and South Caspian is 25, 36, 39 percent, respectively.

Caspian Sea coast

Coast of the Caspian Sea in Turkmenistan

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

Peninsulas of the Caspian Sea

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

Bays of the Caspian Sea

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

Cities on the coast of the Caspian Sea

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

Physiography

Area, depth, volume of water

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

Water level fluctuations

Vegetable world

The flora of the Caspian Sea and its coast is represented by 728 species. Of the plants in the Caspian Sea, algae predominate - blue-green, diatoms, red, brown, charovy and others, of flowering plants - zostera and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were introduced into the Caspian Sea by humans deliberately or on the bottoms of ships.

History of the Caspian Sea

Origin of the Caspian Sea

Anthropological and cultural history of the Caspian Sea

The finds in the Khuto cave off the southern coast of the Caspian Sea indicate that people lived in these parts about 75 thousand years ago. The first mentions of the Caspian Sea and tribes living on its coast are found at Herodotus. Approximately in the V-II centuries. BC NS. the tribes of the Saks lived on the coast of the Caspian. Later, during the period of the settlement of the Turks, during the IV-V centuries. n. NS. Talysh tribes (Talysh) lived here. According to ancient Armenian and Iranian manuscripts, Russians sailed in the Caspian Sea from the 9th-10th centuries.

Exploration of the Caspian Sea

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

Economy of the Caspian Sea

Mining of oil and gas

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

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

Shipping

Shipping is well developed in the Caspian Sea. Ferry services operate on the Caspian Sea, in particular, Baku - Turkmenbashi, Baku - Aktau, Makhachkala - Aktau. The Caspian Sea has a navigable connection with the Sea of Azov through the Volga, Don and Volga-Don Canal.

Fishing and seafood production

Fishing (sturgeon, bream, carp, pike perch, sprat), caviar and seal fishing. More than 90 percent of the world's sturgeon catch is carried out in the Caspian Sea. In addition to industrial production, illegal production of sturgeon and their caviar is flourishing in the Caspian Sea.

Recreational resources

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

Ecological problems

The environmental problems of the Caspian Sea are associated with water pollution as a result of oil production and transportation on the continental shelf, the influx of pollutants from the Volga and other rivers flowing into the Caspian Sea, the vital activity of coastal cities, as well as flooding of certain objects due to the rise in the level of the Caspian Sea. Predatory hunting of sturgeons and their caviar, rampant poaching lead to a decrease in the number of sturgeons and to forced restrictions on their production and export.

International status of the Caspian Sea

Legal status of the Caspian Sea

After the collapse of the USSR, the division of the Caspian Sea for a long time was and still remains the subject of unresolved disagreements related to the division of the resources of the Caspian shelf - oil and gas, as well as biological resources. For a long time, negotiations were going on 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 - on dividing the Caspian Sea by one fifth between all the Caspian states.

With regard to the Caspian, the key is the physical and geographical circumstance that it is a closed inland water body that does not have a natural connection with the World Ocean. Accordingly, the norms and concepts of international maritime law should not be automatically applied to the Caspian Sea, in particular, the provisions of the 1982 UN Convention on the Law of the Sea. economic zone "," continental shelf ", etc.

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

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

Delimitation of sections of the seabed of the Caspian Sea for the purpose of subsoil use

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

On Sunday, August 12, in Kazakhstan's Aktau, the presidents of Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan signed the Convention on the Legal Status of the Caspian Sea. Previously, its status was regulated by the Soviet-Iranian treaties, in which the Caspian Sea was defined as a closed (inland) sea, and each Caspian state had sovereign rights to a 10-mile zone and equal rights to the rest of the sea.

Now, according to the new convention, each country has its own territorial waters (zones 15 miles wide). In addition, the provisions of the 1982 UN Convention on the Law of the Sea will not apply to the Caspian Sea, the seabed will be delineated into sectors, as is done by neighbors in the seas, and sovereignty over the water column will be established on the basis of the principle that it is a lake.

Why is the Caspian not considered a lake or a sea?

To be considered a sea, the Caspian must have access to the ocean, this is one of the most important conditions, according to which a body of water can be called a sea. But the Caspian does not have an outlet to the ocean, therefore it is considered a closed body of water, not connected to the World Ocean.

The second feature that distinguishes sea waters from lakes is their high salinity. The water in the Caspian Sea is indeed salty, but in terms of its salt composition, it occupies an intermediate position between the river and the ocean. In addition, salinity in the Caspian Sea increases towards the south. The Volga delta contains from 0.3 ‰ of salts, and in the eastern regions of the South and Middle Caspian the salinity reaches 13-14 ‰. And if we talk about the salinity of the World Ocean, then it averages 34.7 ‰.

Due to the specific geographic and hydrological characteristics, the reservoir has received a special legal status. The summit participants made a decision according to which the Caspian is an inland water body that has no direct connection with the World Ocean, and therefore cannot be considered a sea, and at the same time, due to its size, water composition and bottom features, it cannot be considered a lake.

What has been achieved since the signing of the Convention?

The new treaty expands opportunities for cooperation between countries, and also involves limiting any military presence of third countries. According to political scientist, director of the Institute of the Newest States Alexei Martynov, the main achievement of the last summit is that its participants managed to stop any talk about the possible construction of NATO military bases and infrastructure facilities in the Caspian Sea.

“The most important thing that has been achieved is to fix that the Caspian will be demilitarized for all Caspian states. There will be no other military personnel, other than those representing the countries that signed the Caspian agreement. This is a fundamental and main issue that was important to fix. Everything else, that which is divided in proportion to the zone of influence, zone of extraction of biological resources, zone of production of shelf resources was not so important. As we remember, in the past twenty years, the military has actively sought to the region. The United States even wanted to build its own military base there, ”Martynov says.

In addition to the distribution of each country's shares in the oil and gas fields of the Caspian Basin, the Convention also provides for the construction of pipelines. As stated in the document, the rules for their laying provide for the consent of only neighboring countries, and not all countries of the Caspian Sea. After the signing of the agreement, Turkmenistan, in particular, announced that it was ready to lay pipelines along the seabed of the Caspian, which would allow it to export its gas through Azerbaijan to Europe. The consent of Russia, which previously insisted that the project could be implemented only with the permission of all five Caspian states, is no longer required. The gas pipeline is planned to be connected in the future to the Trans-Anatolian gas pipeline, through which natural gas will go through the territory of Azerbaijan, Georgia and Turkey to Greece.

“Turkmenistan is not a foreign country to us, but our partner, a country that we consider very important for us on the territory of the post-Soviet space. We cannot be against them receiving an additional impetus for development through such pipeline projects. Gas has long been coming from Turkmenistan and other countries through a different pipeline system, somewhere it even mixes with Russian, and there is nothing wrong with that. If this project works, then everyone will benefit, including Russia. The project should in no way be regarded as some kind of competition. The European market is so big and insatiable, I mean the energy market, that there is enough room for everyone, ”Martynov says.

Today, almost all Turkmen gas is supplied to China, where Russia also intends to supply blue fuel. For this purpose, in particular, a large-scale project for the construction of the Power of Siberia gas pipeline is being implemented. Thus, the geography of gas supplies from both countries can expand - Turkmenistan will gain access to the European market, and Russia will be able to increase its gas supplies to China.

, Kazakhstan, Turkmenistan, Iran, Azerbaijan

Geographical position

Caspian Sea - view from space.

Caspian Sea coast

Coast of the Caspian Sea in Turkmenistan

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

Peninsulas of the Caspian Sea

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

Bays of the Caspian Sea

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

Cities on the coast of the Caspian Sea

Physiography

Area, depth, volume of water

Water level fluctuations

Vegetable world

History of the Caspian Sea

Origin of the Caspian Sea

Anthropological and cultural history of the Caspian Sea

Exploration of the Caspian Sea

Economy of the Caspian Sea

Mining of oil and gas

Shipping

Fishing and seafood production

Recreational resources

Ecological problems

International status of the Caspian Sea

Legal status of the Caspian Sea

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

Delimitation of sections of the seabed of the Caspian Sea for the purpose of subsoil use

The Caspian Sea is the world's largest closed drainage body of water 28.5 m below the level of the World Ocean. The Caspian Sea stretches from north to south for almost 1200 km, the average width is 320 km, the length of the coastline is about 7 thousand km. The area of the Caspian Sea as a result of the lowering of the level decreased from 422 thousand km2 (1929) to 371 thousand km2 (1957). The volume of waters is about 76 thousand km3, the average depth is 180 m. The coastal indentedness coefficient is 3.36. The largest bays: Kizlyarsky, Komsomolets, Kara-Bogaz-Gol, Krasnovodsky, Mangyshlaksky.

There are about 50 islands with a total area of 350 km2. The most significant of them are: Kulaly, Tyuleniy, Chechen, Zhiloy. More than 130 rivers flow into the Caspian Sea. The rivers Volga, Ural, Emba, Terek (total annual runoff 88% of the total river runoff into the sea) flow into the northern part of the sea. On its western coast, the rivers Sulak, Samur, Kura and others, smaller, give 7% of the total runoff. The remaining 5% of the runoff is supplied by the rivers of the Iranian coast.

The relief of the bottom of the Caspian Sea

By the nature of the underwater relief and the peculiarities of the hydrological regime in the Caspian Sea, the North, Middle and South Caspian are distinguished. The North Caspian (about 80 thousand km2) is a shallow, slightly undulating accumulative plain with prevailing depths of 4-8 cape Ridge of banks and islands - the Mangyshlak sill - separates the North and Middle Caspian. Within the Middle Caspian (138 thousand km2) shelf, continental slope and Derbent depression (maximum depth 788 m). The Absheron sill - a chain of banks and islands with depths of 170 m between them - limits the Middle Caspian from the south. The South Caspian (1/3 of the sea area) is distinguished by a very narrow shelf off the western and southern coasts and a much wider shelf off the eastern shores. The deepest sea depth of 1025 m was measured in the South Caspian basin. The bottom of the depression is a flat abyssal plain.

Climate in the Caspian Sea

The main oaric centers that determine the atmospheric circulation over the Caspian Sea: in winter - a spur of the Asian maximum, and in summer - the crest of the Azores maximum and the trough of the South Asian depression. The characteristic features of the climate are the predominance of anticyclonic weather conditions, dry winds, and sharp changes in air temperature.

In the northern and middle parts of the Caspian Sea, from October to April, the winds of the eastern quarter prevail, and from May to September, winds of the northwestern points. In the southern part of the Caspian Sea, the monsoon nature of the winds is clearly expressed.

The average long-term air temperature of the warm months (July-August) over the entire sea is 24-26 ° C. The absolute maximum (up to 44 ° C) was noted on the eastern coast. On average, 200 mm of precipitation falls over the sea per year, with 90-100 mm on the arid eastern coast and 1700 mm in the subtropical southwestern part of the coast. Evaporation in most of the water area is about 1000 mm / year and in the eastern part of the South Caspian and in the area of the Absheron Peninsula up to 1400 mm / year.

Hydrological regime

The currents of the Caspian Sea are formed as a result of the cumulative impact of the wind regime, river runoff and density differences in individual regions. In the northern part of the Caspian Sea, the runoff waters of the Volga River are divided into two branches. The smaller of them goes along the northern coast to the east, merges with the runoff waters of the Ural River and forms a closed cycle. The main part of the Volga runoff flows along the western coast to the south. Somewhat north of the Absheron Peninsula, part of the waters of this current is separated and, crossing the sea, goes to its eastern shores and flows into the waters moving to the north. Thus, a counterclockwise water cycle is formed in the Middle Caspian. The bulk of the waters extending to the south. along the western coast, it enters the South Caspian and, having reached the southern coast, turns to the east, and then goes north along the eastern shores.
The speed of the currents is on the average of the order of 10-15 cm / s. The frequent recurrence of moderate and strong winds leads to a large number of days with significant waves.

The maximum wave height (11 m) is observed in the area of the Absheron sill. The water temperature of the surface layer of the sea in August is about 24-26 ° C in the North and Middle Caspian, up to 29 ° C in the South, 32 ° C in the Krasnovodsk Bay and over 35 ° C in the Kara-Bogaz-Gol Bay. In July-August, upwelling and associated temperature drops to 8-10 ° C are observed near the eastern shores.

Ice formation in the northern part of the Caspian Sea begins in December, ice lasts 2-3 months. In cold winters, drifting ice is carried south to the Absheron Peninsula.
Isolation from the World Ocean, the influx of river waters and the deposition of salts as a result of intense evaporation in the Kara-Bogaz-Gol Bay determine the originality of the salt composition of the Caspian Sea water - a lower content of chlorides and an increased concentration of carbonates in comparison with the waters of the World Ocean. The Caspian Sea is a brackish water basin, the salinity of which is three times less than the normal oceanic one.

The average salinity of the waters in the northwestern part of the Caspian Sea is 1–2 prom, in the area of the northern border of the Middle Caspian 12.7–12.8 and in the South Caspian 13, the maximum salinity (13.3 prom) is observed near the eastern coasts. In the Kara-Bogaz-Gol gulf the salinity of 300 industrial In the North and South Caspian, due to a decrease in inflow and salinization during ice formation, salinity increases in winter. In the South Caspian at this time, salinity decreases due to a decrease in evaporation. In summer, an increase in river runoff causes a decrease in the salinity of waters in the North and Middle Caspian, and increasing evaporation leads to an increase in the salinity of the waters of the South Caspian. Salinity changes from surface to bottom are small. Therefore, seasonal fluctuations in temperature and salinity of water, causing an increase in density, determine the winter vertical circulation of water, which extends to the bottom in the North Caspian, and to a depth of 300 m in the Middle. in winter, the waters of the Middle Caspian through the Absheron threshold and the sliding of cooled high salinity waters from the eastern shallow waters. Studies have shown that due to an increase in water salinity over the past 25 years, the depth of mixing has significantly increased, and accordingly the oxygen content has increased and the hydrogen sulfide contamination of deep waters has disappeared.

Tidal fluctuations in the level of the Caspian Sea do not exceed 3 cm. Short-term non-periodic fluctuations caused by surges can cause the level to rise to 2-2.2 m and decrease to 2 m. Seiches are observed with a period from 10 minutes to 12 hours and an amplitude about 0.7 m. The range of seasonal fluctuations of the level is about 30 cm. A characteristic feature of the hydrological regime of the Caspian Sea is sharp interannual fluctuations of the average annual level. The average level from zero of the Baku tide stock for a century (1830-1930) was 326 cm. The highest level (363 cm) was observed in 1896. From 327 cm (1929) the level dropped to 109 cm (1954), i.e., by 218 In the last decade, the level of the Caspian Sea has stabilized at low elevations with interannual fluctuations of the order of ± 20 cm. Fluctuations in the level of the Caspian Sea are associated with climate changes over the entire basin of this sea.

A system of measures is being developed to prevent a further drop in sea level. There is a project to transfer the waters of the northern rivers Vychegda and Pechora to the Volga river basin, which will increase the flow by about 32 km3. A project was developed (1972) for regulating the flow of Caspian waters into the Kara-Bogaz-Gol Bay.

The coastline of the Caspian Sea is estimated at about 6500 - 6700 kilometers, with islands up to 7000 kilometers. The shores of the Caspian Sea in most of its territory are low and smooth. In the northern part, the coastline is cut by water streams and islands in the Volga and Ural deltas, the shores are low and swampy, and the water surface in many places is covered with thickets. The eastern 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 east coast in the area of the Kazakh Bay and Kara-Bogaz-Gol.

Peninsulas of the Caspian Sea

Major 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 of the Greater Caucasus, on its territory are the cities of Baku and Sumgait
* Buzachi
* Mangyshlak, located on the eastern coast of the Caspian Sea, on the territory of Kazakhstan, on its territory there is the city of Aktau.
* Miancale
* Tub-Karagan

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

The largest islands:

* Ashur-Ada
* Garasu
* Gum
* Dash
* Zira (island)
* Zyanbil
* Kur Dasha
* Hara-Zira
* Sengi-Mugan
* Chechnya (island)
* Chygyl

Large bays of the Caspian Sea:

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

Rivers flowing into the Caspian Sea

130 rivers flow into the Caspian Sea, 9 of which have delta-shaped estuaries. Large rivers flowing into the Caspian Sea are 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 runoff 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 basins. 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 west and northwest, the length of the coastline is 695 kilometers
* Kazakhstan - in the north, north-east and east, the length of the coastline is 2320 kilometers
* Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers
* Iran - in the south, the length of the coastline is 724 kilometers
* Azerbaijan - in the south-west, the length of the coastline is 955 kilometers

Cities on the coast of the Caspian Sea

The largest city - port on the Caspian Sea - Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and employs 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 the southern border of Azerbaijan. To the South-East of the Absheron Peninsula, there is a village of oil workers Neftyanye Kamni, whose structures 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 coast of the Caspian Sea is the 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 coast of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, formerly Krasnovodsk. Several Caspian cities are located on the southern (Iranian) coast, the largest of which is Anzali.

Area, depth, volume of water

The area and volume of water in the Caspian Sea varies significantly depending on the fluctuations in the water level. With 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. 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 according to the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian 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 was 15 meters. Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuation have been conducted since 1837, during this time the highest water level was recorded in 1882 (-25.2 m), the lowest - in 1977 (-29.0 m). , since 1978 the water level has been rising and in 1995 reached the mark of -26.7 m, since 1996 there has been a tendency for the level of the Caspian Sea to decrease again. Scientists associate the reasons for the change 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 pronounced 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 areas with depths less than 25 m, the annual amplitude can reach 25-26 ° C. On average, the water temperature near the western coast is 1–2 ° C higher than that of the eastern one, and in the open sea the water temperature is 2–4 ° C higher than that near the coast. By the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time segment in the upper 2-meter layer. From October to March, the water temperature increases in the southern and eastern, which is especially well traced in the Middle Caspian. Two stable quasi-latitude zones can be distinguished, where temperature gradients are increased. This is, firstly, the border between the North and Middle Caspian, and, secondly, between the Middle and South. At the ice edge, in the northern frontal zone, the temperature in February-March increases from 0 to 5 ° C, in the southern frontal zone, in the area of the Absheron sill, from 7 to 10 ° C. During this period, the least cooled waters are in the center of the South Caspian, which form a quasi-stationary core.

In April-May, the area of minimum temperatures moves to the Middle Caspian, which is associated with a faster warming up 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 ice melting, 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 water warming evens out the horizontal gradients, and the temperature difference between the coastal areas and the open sea does not exceed 0.5 ° C. The heating of the surface layer, which begins in March, disturbs the uniformity in the temperature distribution with depth; in June-September, there is horizontal uniformity in the temperature distribution in the surface layer. 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 South Caspian.

The rise of cold deep waters occurs with varying intensity as a result of the influence of the 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. The upwelling begins in June, but it reaches its highest 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 upwelling focus is gradually shifting from 41-42 ° north. latitude in June, to 43-45 ° north. latitude in September. Summer upwelling is of great importance for the Caspian Sea, fundamentally changing the dynamic processes in the deep water area. In the open areas of the sea in late May - early June, a layer of temperature jump begins, which is most pronounced in August. Most often it is located between the horizons of 20 and 30 m in the middle part of the sea and 30 and 40 m in the southern part. Vertical temperature gradients in the jump layer are very significant and can reach several degrees per meter. In the middle part of the sea, as a result of the drive 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 supply of potential energy, similar to the main thermocline of the World Ocean, then with the termination of the prevailing winds causing upwelling, and with the onset 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 decreases in the middle 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

The salt composition of the waters of the enclosed Caspian Sea differs from that of the ocean. There are significant differences in the ratios of the concentrations of salt-forming ions, especially for the waters of areas under the direct influence of continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total salt 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, the content of calcium and magnesium cations is almost twice as high as in the Sea of Azov, and the content of sulfate anions is three times higher. The salinity of water changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and the Urals up to 10-11 units. psu on the border with the Middle Caspian.

Mineralization in shallow salty bays-kultuk 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-latitude location is observed. The greatest desalination associated with the spread of river runoff over the sea area is observed in June. The formation of the salinity field in the North Caspian is greatly influenced by the wind field. In the middle and southern parts of the sea, salinity fluctuations are small. Basically, it is 11.2-12.8 units. psu, increasing southerly and easterly. Salinity increases insignificantly with depth (by 0.1-0.2 psu units).

In the deep-water part of the Caspian Sea, in the vertical salinity profile, there are characteristic isohaline troughs and local extrema in the region 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 amount of salinity is also strongly dependent on sea level and (which is interconnected) on the volume of continental runoff.

Bottom relief

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

Climate

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 highest temperature recorded on the east coast is 44 degrees.

Average annual rainfall is 200 millimeters per year, from 90-100 millimeters in the arid eastern part to 1,700 millimeters off the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea - 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 - 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, northern winds prevail in the wind rose. In the autumn and winter months, the winds increase, the speed of the winds often reaches 35-40 meters per second. The most windy areas are the Apsheron Peninsula and the vicinity of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.

Currents

The circulation of water in the Caspian Sea is associated with runoff and winds. Since most of the runoff is in the North Caspian, northern currents prevail. The intense northern current carries water from the North Caspian along the western coast to the Absheron Peninsula, where the current splits 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 is represented by 1809 species, of which 415 are vertebrates. In the Caspian world, 101 species of fish are registered, and most of the world's stocks of sturgeon, as well as such freshwater fish as roach, carp, and pike perch, are concentrated in the Caspian world. The Caspian Sea is a habitat for fish such as carp, mullet, sprat, kutum, bream, salmon, perch, 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

Origin of the Caspian Sea

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

Anthropological and cultural history of the Caspian Sea

Exploration of the Caspian Sea

The exploration of the Caspian Sea was started by Peter the Great, when, on his order, in 1714-1715, an expedition was organized 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 survey of the banks was carried out by I.F.Kolodkin, in the middle of the 19th century. - instrumental geographic survey under the direction of N. A. Ivashintsev. Since 1866, for more than 50 years, expeditionary studies on the hydrology and hydrobiology of the Caspian have been conducted under the leadership of N.M. Knipovich. In 1897, the Astrakhan Research Station was founded. In the first decades of Soviet power in the Caspian Sea, geological research by I.M.Gubkin and other Soviet geologists was actively carried out, mainly aimed at finding oil, as well as research on the study of the water balance and fluctuations in the level of the Caspian Sea.

Mining of oil and gas

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 in industrial volumes on the Absheron Peninsula, 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

Fishing and seafood production

Recreational resources

Ecological problems

Frontier dispute over the status of the Caspian Sea

After the collapse of the USSR, the division of the Caspian Sea for a long time was and still remains the subject of unresolved disagreements related to the division of the resources of the Caspian shelf - oil and gas, as well as biological resources. For a long time, negotiations were going on 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 on dividing the Caspian by one fifth between all the 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