Caspian Sea where it is located. Sefidrud is a high-water river of the Caspian Sea. The history of the appearance of the Caspian Sea

Caspian Sea

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

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

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

The Caspian Sea washes the shores of five coastal states:

Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, the length of the coastline is 695 kilometers Kazakhstan - in the north, northeast and east, the length of the coastline is 2320 kilometers Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers Iran - in the south, the length of the coastline - 724 kilometers Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

Water temperature

It 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 water temperature difference is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average, the water temperature near the western coast is 1 - 2 °C higher than that of the eastern coast, and in the open sea the water temperature is 2 - 4 °C higher than near the coasts.

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

Animal world

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

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, char and others, of flowering - zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought into the Caspian Sea by man either consciously or on the bottoms of ships.

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 resources of oil and gas condensate 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 on 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.

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

The Caspian Sea is conditionally divided according to physical and geographical conditions into 3 parts - the Northern Caspian, the Middle Caspian and the Southern Caspian. The conditional border between the North and the Middle Caspian we pass along the Chechen line (island)- Tyub-Karagansky Cape, between the Middle and South Caspian - along the line of the Residential (island)- Gan Gulu (cape). The area of the Northern, Middle and Southern Caspian is 25, 36, 39 percent respectively.

According to one of the hypotheses, the Caspian Sea got its name in honor of the ancient tribes of horse breeders - the Caspians, who lived before our era on the southwestern coast of the Caspian Sea. Throughout the history of its existence, the Caspian Sea had about 70 names for different tribes and peoples: the Hyrcanian Sea; The Khvalyn Sea or the Khvalis Sea is an ancient Russian name, derived from the name of the inhabitants of Khorezm, who traded in the Caspian Sea - Khvalis; Khazar Sea - name in Arabic (Bahr-al-Khazar), Persian (Daria-e Khazar), Turkish and Azerbaijani (Khazar Denizi) languages; Abeskun Sea; Saray Sea; Derbent Sea; Sihai and other names. In Iran, the Caspian Sea is still called the Khazar or Mazenderan (by the name of the people inhabiting the coastal province of Iran of the same name).

The coastline of the Caspian Sea is estimated at about 6500 - 6700 kilometers, with islands - up to 7000 kilometers. The shores of the Caspian Sea in most of its territory are low-lying and smooth. In the northern part, the coastline is indented by water streams and islands of the Volga and Ural deltas, the shores are low and swampy, and the water surface is covered with thickets in many places. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding coasts are on the west coast in the area of the Apsheron Peninsula and on the east coast in the area of the Kazakh Gulf and Kara-Bogaz-Gol.

Large peninsulas of the Caspian Sea: Agrakhan Peninsula, Absheron Peninsula, Buzachi, Mangyshlak, Miankale, Tub-Karagan.

There are about 50 large and medium-sized islands in the Caspian Sea with total area approximately 350 square kilometers. The largest islands: Ashur-Ada, Garasu, Gum, Dash, Zira (island), Zyanbil, Kyur Dashy, Khara-Zira, Sengi-Mugan, Chechnya (island), Chygyl.

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

Off the eastern coast is the salt lake Kara Bogaz Gol, which until 1980 was a bay-lagoon of the Caspian Sea, connected to it by a narrow strait. In 1980, a dam was built separating Kara-Bogaz-Gol from the Caspian Sea, in 1984 a culvert was built, after which the level of Kara-Bogaz-Gol dropped by several meters. In 1992, the strait was restored, through which water leaves the Caspian Sea to Kara-Bogaz-Gol and evaporates there. Every year, 8-10 cubic kilometers of water enters Kara-Bogaz-Gol from the Caspian Sea (according to other sources - 25 thousand kilometers) and about 150 thousand tons of salt.

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

The area of the Caspian Sea basin is approximately 3.1 - 3.5 million square kilometers, which is approximately 10 percent of the world's closed water basins. The length of the Caspian Sea basin from north to south is about 2,500 kilometers, from west to east - about 1,000 kilometers. The Caspian Sea basin covers 9 states - Azerbaijan, Armenia, Georgia, Iran, Kazakhstan, Russia, Uzbekistan, Turkey and Turkmenistan.

The Caspian Sea washes the shores of five coastal states:

Russia (Dagestan, Kalmykia and Astrakhan region)- in the west and northwest, the length of the coastline is 695 kilometers
Kazakhstan - in the north, northeast and east, the length of the coastline is 2320 kilometers
Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers
Iran - in the south, the length of the coastline - 724 kilometers
Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

The largest city - a port on the Caspian Sea - Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and has 2,070 thousand people (2003) . Other large Azerbaijani Caspian cities are Sumgayit, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the South-East of the Absheron Peninsula, there is a settlement of oil workers Neftyanye Kamni, whose facilities stand on artificial islands, flyovers and technological platforms.

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. 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 the eastern shore 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 shore of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, formerly Krasnovodsk. Several Caspian cities are located in the southern (Iranian) coast, the largest of them - Anzeli.

The area and volume of water in the Caspian Sea varies significantly depending on fluctuations in water levels. At a water level of -26.75 m, the area was approximately 392,600 square kilometers, the volume of water was 78,648 cubic kilometers, which is approximately 44 percent of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface level. In terms of maximum depth, the Caspian Sea is second only to Baikal (1620 m.) and Tanganyika (1435 m.). The average depth of the Caspian Sea, calculated from the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

The water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past 3 thousand years, the amplitude of changes in the water level of the Caspian Sea has amounted to 15 meters. Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during this time the highest water level was recorded in 1882 (-25.2 m.), the lowest - in 1977 (-29.0 m.), since 1978 the water level has risen and in 1995 reached -26.7 m, since 1996 there has been a downward trend again. Scientists associate the causes of changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.

The water temperature is subject to significant latitudinal changes, most pronounced in winter, when the temperature varies from 0 - 0.5 °C at the ice edge in the north of the sea to 10 - 11 °C in the south, i.e. the water temperature difference is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average, the water temperature near the western coast is 1 - 2 °C higher than that of the eastern coast, and in the open sea the water temperature is 2 - 4 °C higher than near the coasts. According to the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time intervals can be distinguished in the upper 2-m layer. From October to March, the water temperature increases in the south and east, which is especially evident in the Middle Caspian. Two stable quasi-latitudinal zones can be distinguished, where the temperature gradients are 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 Apsheron threshold, from 7 to 10 °C. During this period, the least chilled waters are in the center of the South Caspian, which form a quasi-stationary core. In April-May, the area of minimum temperatures moves to the Middle Caspian, which is associated with faster warming of waters in the shallow northern part of the sea. True, at the beginning of the season in the northern part of the sea, a large amount of heat is spent on melting ice, but already in May the temperature rises here to 16 - 17 °C. In the middle part, the temperature at this time is 13 - 15 °C, and in the south it rises to 17 - 18 °C. The spring warming of the water evens out the horizontal gradients, and the temperature difference between coastal areas and the open sea does not exceed 0.5 °C. The heating of the surface layer, which begins in March, breaks the uniformity in the temperature distribution with depth. In June-September, there is a horizontal uniformity in the temperature distribution in surface layer. In August, which is the month of the highest warming, the water temperature throughout the sea is 24 - 26 °C, and in southern regions 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 prevailing summer season northwest winds. Wind this direction causes the outflow of warm surface waters from the coast and the rise of colder waters from the intermediate layers. Upwelling starts in June, but it reaches its highest intensity in July-August. As a result, there is a decrease in temperature on the surface of the water. (7 - 15°C). Horizontal temperature gradients reach 2.3 °C at the surface and 4.2 °C at a depth of 20 m. in June to 43 - 45 ° N in September. Summer upwelling has great importance for the Caspian Sea, radically changing the dynamic processes in the deep water area. In the open areas of the sea in late May - early June, the formation of a temperature jump layer begins, which is most clearly expressed in August. Most often, it is located between the horizons of 20 and 30 m in the middle part of the sea and 30 and 40 m in the southern part. Vertical temperature gradients in the shock layer are very significant and can reach several degrees per meter. In the middle part of the sea, due to the surge near the eastern coast, the shock layer rises close to the surface. Since there is no stable baroclinic layer in the Caspian Sea with a large potential energy reserve similar to the main thermocline of the World Ocean, with the cessation of the effect of the prevailing winds that cause upwelling, and with the onset of autumn-winter convection in October-November, the temperature fields are rapidly reorganized to the winter regime. In the open sea, the water temperature in the surface layer drops in the middle part to 12 - 13 °C, in the southern part to 16 - 17 °C. In the vertical structure, the shock layer is washed out due to convective mixing and disappears by the end of November.

The salt composition of the waters of the closed Caspian Sea differs from that of the ocean. There are significant differences in the ratios of the concentrations of salt-forming ions, especially for the waters of areas under the direct influence of continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total amount of salts 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, chloride and magnesium. The least conservative are calcium and bicarbonate ion. In the Caspian Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of Azov, and sulfate anion is three times higher. The salinity of water changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and the Urals up to 10 - 11 units. psu on the border with the Middle Caspian. Mineralization in shallow saline bays-kultuks can reach 60 - 100 g/kg. In the Northern Caspian, during the entire ice-free period from April to November, a quasi-latitudinal salinity front is observed. The greatest desalination associated with the spread of river runoff over the sea area is observed in June. On the formation of salinity field in the Northern Caspian big influence renders the wind field. In the middle and southern parts of the sea, salinity fluctuations are small. Basically, it is 11.2 - 12.8 units. psu, increasing in the southern and eastern directions. Salinity increases slightly with depth. (at 0.1 - 0.2 psu). In the deep-water part of the Caspian Sea, in the vertical salinity profile, characteristic troughs of isohalines and local extrema are observed in the area of the eastern continental slope, which indicate the processes of near-bottom creep of waters becoming saline in the eastern shallow waters of the South Caspian. Salinity is also highly dependent on sea level and (which is related) from the amount of continental runoff.

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

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

Winds often blow on the territory of the Caspian Sea, their average annual speed is 3-7 meters per second, the wind rose is dominated by northern winds. In the autumn and winter months, the winds increase, the wind speed often reaches 35-40 meters per second. The most windy territories are the Apsheron Peninsula and the environs of Makhachkala-Derbent, the most high wave- 11 meters.

The circulation of water in the Caspian Sea is connected with the runoff and winds. Since most of the water flow falls on the Northern Caspian, northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current splits into two branches, one of which moves further along West Bank, the other goes to the Eastern Caspian.

The fauna of the Caspian Sea is represented by 1810 species, of which 415 are vertebrates. 101 species of fish are registered in the Caspian world, and most of the world's stocks of sturgeon are concentrated in it, as well as such freshwater fish as vobla, carp, pike perch. The Caspian Sea is the habitat of such fish as carp, mullet, sprat, kutum, bream, salmon, perch, pike. The Caspian Sea is also inhabited by a marine mammal - the Caspian seal. Since March 31, 2008, 363 dead seals have been found on the coast of the Caspian Sea in Kazakhstan.

It is known that the sea is part of the oceans. From this geographically correct point of view, the Caspian cannot be considered a sea, because it is separated from the ocean by huge land masses. The shortest distance from the Caspian to the Black Sea, the closest of the seas included in the system of the World Ocean, is 500 kilometers. Therefore, it would be more correct to speak of the Caspian as a lake. This is the world's largest lake, often referred to simply as the Caspian or lake-sea.

The Caspian Sea has a number of features of the sea: its water is salty (however, there are other salt lakes), the area is not much inferior to the area of such seas as the Black, Baltic, Red, Northern, and even exceeds the area of Azov and some others (however, Canadian Lake Superior also huge area, like the three Seas of Azov). In the Caspian, fierce storm winds and huge waves are frequent (and this is not uncommon in Baikal).

So, after all, the Caspian Sea is a lake? That's Wikipedia says it Yes, and the Great Soviet Encyclopedia answers that no one has yet been able to give an exact definition of this issue - "A generally accepted classification does not exist."

Do you know why this is very important and fundamental? And here's why...

The lake belongs to inland waters- sovereign territories of coastal states to which the international regime does not apply (the principle of non-intervention of the UN in the internal affairs of states). But the water area of the sea is divided differently, and the rights of coastal states are completely different here.

In terms of its geographical position, the Caspian itself, in contrast to the land territories surrounding it, has not been the object of any targeted attention from the coastal states for many centuries. Only at the beginning of the XIX century. between Russia and Persia, the first treaties were concluded: Gulistan (1813) 4 and Turkmanchaisky (1828), summing up the results of the Russian-Persian war, as a result of which Russia annexed a number of Transcaucasian territories and received the exclusive right to maintain a navy in the Caspian Sea. Russian and Persian merchants were allowed to freely trade on the territory of both states and use the Caspian Sea to transport goods. The Turkmanchay Treaty confirmed all these provisions and became the basis for maintaining international relations between the parties until 1917.

After the October Revolution of 1917, in a note dated January 14, 1918, by the new Russian government that came to power, it renounced its exclusive military presence in the Caspian Sea. The agreement between the RSFSR and Persia of February 26, 1921 declared invalid all agreements concluded before it by the tsarist government. The Caspian Sea became a body of water for common use by the parties: both states were granted equal rights of free navigation, except in cases where the crews of Iranian ships could include citizens of third countries using the service for unfriendly purposes (Article 7). The 1921 agreement did not provide for a maritime border between the parties.

In August 1935, the following treaty was signed, the parties to which were new subjects of international law - the Soviet Union and Iran, which acted under the new name. The parties reaffirmed the provisions of the 1921 agreement, but introduced into the agreement a new concept for the Caspian - a 10-mile fishing zone, which limited the spatial limits of this fishery for its participants. This was done in order to control and conserve the living resources of the reservoir.

In the context of the outbreak of World War II, unleashed by Germany, an urgent need arose to conclude a new treaty between the USSR and Iran on trade and navigation in the Caspian. The reason for this was anxiety Soviet side, caused by Germany's interest in intensifying its trade relations with Iran and the danger of using the Caspian Sea as one of the stages of the transit route. The treaty signed between the USSR and Iran in 1940 10 protected the Caspian Sea from such a prospect: it repeated the main provisions of the previous agreements, which provided for the stay in its waters of the ships of only these two Caspian states. It also included a provision for its indefinite validity.

The collapse of the Soviet Union radically changed the regional situation in the former Soviet space, in particular in the Caspian region. Among the large number of new problems, the problem of the Caspian also arose. Instead of two states - the USSR and Iran, which previously bilaterally resolved all emerging issues of maritime navigation, fishing and the use of its other living and non-living resources, now there are five of them. Of the former, only Iran remained, Russia took the place of the USSR on the rights of succession, the remaining three are new states: Azerbaijan, Kazakhstan, Turkmenistan. They used to have access to the Caspian, but only as republics USSR, not independent states. Now, having become independent and sovereign, they have the opportunity to participate on an equal footing with Russia and Iran in the discussion and decision-making in the consideration of all the above issues. This was also reflected in the attitude of these states to the Caspian, since all five states that had access to it showed equal interest in the use of its living and non-living resources. And this is logical, and most importantly, justified: the Caspian Sea is rich in natural resources, both fish stocks and black gold - oil and blue fuel - gas. Exploration and production of the last two resources have long been the subject of the most heated and protracted negotiations. But not only them.

In addition to the presence of rich mineral resources, about 120 species and subspecies of fish live in the waters of the Caspian Sea, here is the world gene pool of sturgeons, the extraction of which, until recently, accounted for 90% of their total world catch.

Due to its location, the Caspian Sea has traditionally and long been widely used for navigation, acting as a kind of transport artery between the peoples of the coastal states. Along its banks are such large seaports, as the Russian Astrakhan, the capital of Azerbaijan Baku, the Turkmen Turkmenbashi, the Iranian Anzeli and the Kazakh Aktau, between which trade, cargo and passenger sea transport routes have long been laid.

And yet, the main object of attention of the Caspian states is its mineral resources - oil and natural gas, to which each of them can claim within the limits that should be determined by them collectively on the basis of international law. And for this, they will have to divide between themselves both the Caspian Sea and its bottom, in the depths of which its oil and gas are hidden, and develop rules for their extraction with minimal damage to a very fragile environment, especially the marine environment and its living inhabitants.

The main obstacle in resolving the issue of the beginning of a wide extraction of the mineral resources of the Caspian Sea for the Caspian states continues to be its international legal status: should it be considered a sea or a lake? The complexity of the issue lies in the fact that these states themselves must solve it, and so far no agreement has been observed in their ranks. But at the same time, each of them seeks to start extracting Caspian oil and natural gas as soon as possible and make their sale abroad a permanent source of funds to form their budget.

Therefore, the oil companies of Azerbaijan, Kazakhstan and Turkmenistan, without waiting for the end of the settlement of existing disagreements on the territorial division of the Caspian, have already begun active production of its oil, in the hope of ceasing to be dependent on Russia, turning their countries into oil-producing countries and already in this capacity begin build their own long-term trade relations with neighbors.

However, the issue of the status of the Caspian Sea remains unresolved. Regardless of whether the Caspian states agree to consider it a “sea” or a “lake”, they will have to apply the principles corresponding to the choice made or develop their own for this case to the territorial division of its water area and bottom.

Kazakhstan was in favor of recognizing the Caspian as a sea. Such recognition will make it possible to apply to the division of the Caspian the provisions of the 1982 UN Convention on the Law of the Sea on Internal Waters, the Territorial Sea, the Exclusive Economic Zone, and the Continental Shelf. This would allow the coastal states to gain sovereignty over the subsoil of the territorial sea (Article 2) and exclusive rights to explore and develop the resources of the continental shelf (Article 77). But the Caspian cannot be called a sea from the standpoint of the UN Convention on the Law of the Sea of 1982, since this body of water is closed and has no natural connection with the oceans.

In this case, the option of joint use of its water area and bottom resources is also excluded.

In the treaties between the USSR and Iran, the Caspian Sea was considered as a border lake. With the legal status of a "lake" given to the Caspian Sea, it is supposed to be divided into sectors, as is done with respect to border lakes. But there is no norm in international law obliging states to do just that: division into sectors is an established practice.

The Russian Foreign Ministry has repeatedly made statements that the Caspian is a lake, and its waters and subsoil are the common property of the coastal states. Iran also considers the Caspian Sea as a lake from the position fixed in the treaties with the USSR. The government of the country believes that this status implies the creation of a consortium for the unified management of the extraction and use of its resources. littoral states. Some authors also express this opinion, for example, R. Mammadov believes that with such a status, the extraction of hydrocarbon resources in the Caspian Sea by these states should be carried out jointly.

In the literature, there has been a proposal to give the Caspian Sea the status of a “sui generis” lake, and in this case we are talking about a special international legal status of such a lake and its special regime. Under the regime, it is assumed that the states jointly develop their own rules for the use of its resources.

Thus, the recognition of the Caspian as a lake does not require its mandatory division into sectors - each coastal state has its own part. In addition, there are no norms in international law on the division of lakes between states: this is their good will, behind which certain internal interests may be hidden.

At present, all the Caspian states recognize that the modern legal regime was established by the established practice of its use, but now the Caspian is in actual common use not by two, but by five states. Even at the meeting of foreign ministers held in Ashgabat on November 12, 1996, the Caspian states confirmed that the status of the Caspian Sea could be changed only with the consent of all five coastal states. Later, this was also confirmed by Russia and Azerbaijan in a joint statement dated January 9, 2001 on the principles of cooperation, as well as in the Declaration on cooperation in the Caspian Sea signed between Kazakhstan and Russia dated October 9, 2000.

But in the course of numerous Caspian negotiations, conferences and four summits of the Caspian states (Ash-Khabad summit on April 23-24, 2002, Tehran summit on October 16, 2007, Baku summit on November 18, 2010 and Astrakhan summit on September 29, 2014 d.) the Caspian countries failed to reach agreement.

More productive so far is cooperation at the bilateral and trilateral levels. Back in May 2003, Russia, Azerbaijan and Kazakhstan signed an agreement on the junction of the lines of delimitation of adjacent sections of the bottom of the Caspian Sea, which was based on previous bilateral agreements. In the current situation, Russia, by its participation in these agreements, seemed to confirm that the agreements between the USSR and Iran are outdated and do not correspond to the existing realities.

In the Agreement of July 6, 1998 between the Russian Federation and the Republic of Kazakhstan on the delimitation of the bottom of the northern part of the Caspian Sea in order to exercise sovereign rights to subsoil use, the delimitation of the seabed between adjacent and opposite sides along a modified median line based on the principle of fairness was announced. - Livosti and agreements of the parties. At the bottom of the section, the states have sovereign rights, but their common use of the water surface is preserved.

Iran perceived this agreement as separate and violating the previous Treaties with the USSR of 1921 and 1940. However, it should be noted that in the preamble of the 1998 agreement, to which Russia and Kazakhstan were parties, the agreement was considered as a temporary measure pending the signing of the convention by all the Caspian states.

Later, on July 19 of the same year, Iran and Russia made a joint statement in which they proposed three possible scenarios for the delimitation of the Caspian Sea. First: the sea should be shared on the basis of the condominium principle. The second scenario boils down to dividing the water area, waters, bottom and subsoil into national sectors. The third scenario, which is a compromise between the first and second options, suggests dividing only the bottom between the coastal states, and considers the water surface to be common and open to all coastal countries.

The existing options for the delimitation of the Caspian Sea, including those mentioned above, are possible only if there is good political will on the part of the parties. Azerbaijan and Kazakhstan have clearly expressed their position from the very beginning of the process of multilateral consultations. Azerbaijan considers the Caspian Sea to be a lake and, therefore, it should be divided. Kazakhstan proposes to consider the Caspian as a closed sea, referring to the 1982 UN Convention (Articles 122, 123), and, accordingly, advocates its division in the spirit of the Convention. Turkmenistan has long supported the idea of joint management and use of the Caspian, but foreign companies already developing resources off the coast of Turkmenistan influenced the policy of its president, who began to object to the establishment of a condominium regime, supporting the position of dividing the sea.

Azerbaijan was the first of the Caspian states to start using the hydrocarbon resources of the Caspian under the new conditions. After the conclusion of the “Deal of the Century” in September 1994, Baku expressed a desire to declare the sector adjacent to it integral part its territory. This provision was also enshrined in the Constitution of Azerbaijan, adopted in order to exercise sovereign rights to subsoil use, Moscow, July 6, 1998 at a referendum on November 12, 1995 (Article 11). But such a radical position from the very beginning did not correspond to the interests of all other coastal states, especially Russia, which expresses fears that this will open access to the Caspian Sea to countries in other regions. Azerbaijan agreed to a compromise. In the Agreement between the Russian Federation and Azerbaijan on the delimitation of adjacent sections of the Caspian Sea in 2002, a provision was fixed in which the division of the bottom was carried out using the median line, and the water area of the reservoir remained in joint use.

Unlike Azerbaijan, which expressed a desire to completely divide the Caspian, Iran proposes to leave its bowels and water for joint use, but does not object to the option of dividing the Caspian into 5 equal parts. Accordingly, each member of the Caspian five would be allocated 20 percent of the total territory of the reservoir.

Russia's point of view was changing. For a long time Moscow insisted on the establishment of a condominium, but wishing to build a long-term policy with its neighbors, which did not benefit from considering the Caspian as the property of five coastal states, it changed its position. This then prompted the states to start a new stage of negotiations, after which, in 1998, the above Agreement was signed, where Russia declared that it was “ripe” for the division of the Caspian Sea. Its main principle was the position "the water is common - we divide the bottom."

Taking into account the fact that agreements have been reached between some of the Caspian states, namely Azerbaijan, Kazakhstan and Russia, on the conditional delimitation of spaces in the Caspian, we can conclude that they are actually satisfied with the already established regime with the division of its bottom along a modified median line and sharing the surface of the reservoir for navigation and fishing.

However, the lack of complete clarity and unity in the position of all countries of the coast prevents the Caspian states themselves from developing oil production. And oil is of key importance to them. There are no unequivocal data regarding their reserves in the Caspian Sea. According to the US Energy Information Agency in 2003, the Caspian was ranked second in oil reserves and third in gas reserves. The data of the Russian side is different: they speak of an artificial overestimation by Western experts of the energy resources of the Caspian Sea. Differences in assessments are due to the political and economic interests of regional and external players. The data distortion factor was the geopolitical significance of the region, with which the foreign policy plans of the US and the EU are connected. Zbigniew Brzezinski back in 1997 expressed the opinion that this region is the "Eurasian Balkans".

Yes, geography can sometimes break my brain quite a bit. You look at the map and see the name - "Caspian Sea". What a normal person would think in such a situation - yes, of course, it would not occur to him that we are talking about ... a lake! So now I'll tell you why the Caspian Sea is not a sea, but a lake, how did it happen and what is this strange whirlwind with names.

The sea is not the sea

Yes, the Caspian Sea is a geographical object, the essence of which does not really coincide with its name.

The fact is that by name it is a sea, but in fact it is a lake. They called it the sea due to the large size and salinity of the water. After all, people did not want to delve into geographical nuances - the name appeared a long time ago.

Only really Caspian lake has no outlet to the ocean. And this is one of the most important conditions for which a body of water is called a sea. It turns out that without access to the ocean, the Caspian is considered a lake. Big, salty and very similar to the sea - but still a lake.

So, once again I will list what a reservoir should have in order for it to be considered a sea:

A lake is not a lake

The Caspian Sea-Lake, however, is different from other lakes. It is indeed very large - so much so that it washes the territory five different countries. In addition, it has about fifty fairly large islands.

Yes and water there salty. However, by maritime standards, all the same not enough- which again inclines us towards the fact that this is a lake.

And the abundance of waters of the Caspian decreases over the years. Long time it replenished the Volga, but in recent years it she becomes shallow- respectively, the water level in the Caspian Sea is also decreasing. So, perhaps in a hundred or two years it will turn into a regular-sized lake if global warming does not stop.

Throughout the world, the Caspian Sea is unanimously considered a lake. Even his water territory is divided not according to those international laws that were invented for marine areas, but lake legislation.

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In a huge number of books I read about the Caspian Sea, its greatness and how local people love and respect it. And indeed, I was very surprised when I once found myself on the shore of this sea. But after a while I began to hear that it is called a lake. I was wondering why is this happening? And then I delved into literature in order to understand the situation.

Why the Caspian is a lake

There is one main reason why people no longer consider this beautiful body of water to be the sea - the lack of access to the ocean. Usually the sea must have a strait connecting it with a larger part of a huge water reservoir - the oceans. For example, we can recall the Sea of \u200b\u200bAzov, with its Kerch Strait, or the following Black, with the Bosphorus. A succession of such straits and seas leads them to Atlantic Ocean.

But the Caspian Sea is a unique case. There is not a single drain from it. Even the Angara River flows out of the great Baikal.

The only weighty argument for the fact that the Caspian is a sea is its salinity. But the numbers speak against it. The average percentage of water salinity here is 12.9%, while in other seas this figure is 35%.

Where does the Caspian Sea draw water from?

In this, the largest, as I figured out, lake on the planet, five great rivers flow at once:

Samur;
Volga;
Ural;
Terek;
Kura.

At the confluence of the rivers, the water is almost fresh, but closer to the south, the lake saturates it with its own salt reserves.

Fluctuations in the level of the Caspian Sea

The locals told me that the Caspian is fickle. The water level is extremely variable. This is due to the change in the level of the rivers, the internal sources of this sea-lake. Climate plays a big role. On this moment The height of the Caspian Sea is steadily increasing, reaching almost 26 meters below sea level. For comparison: 20 years ago, this figure was almost two meters lower.

This has pros and cons. On the one hand, navigation is improving, and on the other, pastures and fields are flooded.

The inhabitants of the coast love the Caspian, despite its unusual nature and stormy character. I liked him very much too!

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Many names, not only toponyms, have always surprised me with their seeming groundlessness. Guinea pigs are not guinea pigs, bats are not related to rodents, and the Caspian Sea is generally a lake.

I didn't say "apparently" for nothing. Every name has a backstory. And often very interesting.

How the sea became a lake

The Caspian Sea is not so undeservedly called the sea. Once it really was part of the ocean.

It even rests in the bed of the earth's crust ocean type.

The Caspian is brackish although the salinity of the water is variable. Near the mouth of the Volga, which flows into it, the salinity of the water is minimal. The size of the Caspian in no way inferior to the sea. Its surface area: 371,000 km².

main reason, according to which Caspian considered to be lake, it is his isolation from the oceans. He has nothing to do with him.

But it was many years ago.

It all started with Sarmatian Sea, which existed more than 13 million years ago. It was loosely associated with by sea mediterranean, but later lost this connection and began to desalinate. Then it briefly restored contact with the sea, but then lost it again.

6.5 - 5.2 million years ago formed Pontic Sea, which is smaller in area. Which, moreover, was soon divided into several unconnected reservoirs. The resulting Balakhani lake can be considered a grandmother Caspian Sea. It gained and lost access to the sea several more times, raised and lowered the water level, changed in size, until finally something appeared. Caspian Sea as we see it now.

How to consider the Caspian Sea: the sea or the lake

And the disputes here are not so much between geographers, but between politicians.

The Caspian washes the territories at once five states:

Kazakhstan;
Russia;
Turkmenistan;
Iran;
Azerbaijan.

But Caspian Sea is not only important transport node, but also a storehouse of various natural resources, among which:

oil;
gas;
fish, including sturgeon.

And here comes the problem with legal status of the Caspian. If you count it by sea, then when using it, states should focus on United Nations Convention on the Law of the Sea 1982. But the procedure for the use of international rivers and lakes, as a rule, is established by the coastal states themselves, concluding appropriate agreements.

Full agreement between the countries has not yet been reached.

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I rested somehow in the camp. It's no secret that almost every day there are competitions for the entertainment of children and youth. So. Was we have quiz. Question: "Which lake is the largest?" One guy of about fifteen was the first to raise his hand and answer: "Baikal." The strangest thing was that his answer was counted as correct! How so? Isn't the Caspian Sea the largest lake? Now I will explain to you.

How to distinguish the sea from the lake

I will list several signs by which a body of water is defined as a sea.

1. Rivers can flow into the sea.

2. The outer sea has direct access to the ocean.

3. If the sea is inland, then it is connected by straits with other seas or directly with the ocean.

Is the Caspian Sea suitable for the parameters of the sea

Need to check, does the Caspian Sea have signs of a sea. into it really rivers flow, but they flow into many bodies of water: seas, lakes, oceans, and other rivers. The Caspian Sea is surrounded from all sides dry land. Is it really inland sea? Then it should be connected to the Black or Azov seas some strait. Strait Same No. Exactly due to the lack of access to the World Ocean, the Caspian Sea is considered a lake.

“But why was it then called the sea, if it is a lake?”- you ask. Answer very simple: because of his large sizes and salinity. Indeed, The Caspian Sea is several times larger than the Sea of Azov and almost the same size as the Baltic Sea..

Great! The quiz issue has been resolved. Soap judge!!!

Well then I told, that the Caspian Sea In fact - lake. Now I want to you provide small collection of interesting facts about this lake.

1. The Caspian Sea is below sea level (-28 m), which once again proves that this is a lake.

2. BC around the lake area lived nomadic Caspian tribes,in honor of which he was nicknamed the Caspian.

3. It the deepest enclosed body of water on the planet.

4. Many believe that the name of the group "Caspian cargo" is related to the Caspian Sea. In a way they are right No). In fact the expression "Caspian cargo" can refer to any illegal cargo.

5.Caspian Sea Fine suitable for tourism. Under the USSR, a large number of sanatoriums were built here. Today same here you can see many hotels, water parks and beaches.

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

The Caspian Sea is located in a vast area of internal flow and occupies a deep tectonic depression. The water level in the sea is at around 27 m below the level of the World Ocean, the area is about 390 thousand km 2, the volume is about 78 thousand km 3. The greatest depth is 1025 m. With a width of 200 to 400 km, the sea is elongated along the meridian for 1030 km.

The largest bays: in the east - Mangyshlak, Kara-Bogaz-Gol, Turkmenbashi (Krasnovodsk), Turkmen; in the west - Kizlyar, Agrakhan, Kyzylagadzh, Baku Bay; in the south - shallow lagoons. There are many islands in the Caspian Sea, but almost all of them are small, with a total area of less than 2 thousand km 2. In the northern part, there are numerous small islands adjacent to the Volga delta; larger ones - Kulaly, Morskoy, Tyuleniy, Chechen. Off the western shores is the Apsheron archipelago, to the south lie the islands of the Baku archipelago, off the eastern coast is the narrow island of Ogurchinsky, elongated from north to south.

The northern shores of the Caspian Sea are low-lying and very sloping, characterized by a wide development of droughts formed as a result of surge phenomena; deltaic shores are also developed here (the deltas of the Volga, the Urals, and the Terek) with an abundant supply of terrigenous material; the Volga delta stands out with extensive reed beds. The western shores are abrasion, south of the Apsheron Peninsula for the most part accumulative delta type with numerous bays and spits. southern shores base. The eastern shores are mostly deserted and low-lying, composed of sands.

relief and geological structure bottom.

The Caspian Sea is located in a zone of increased seismic activity. In the city of Krasnovodsk (now Turkmenbashi) in 1895 there was a strong earthquake measuring 8.2 on the Richter scale. Eruptions of mud volcanoes are often observed on the islands and the coast of the southern part of the sea, leading to the formation of new shoals, banks and small islands, which are washed away by waves and reappear.

According to the peculiarities of physical and geographical conditions and the nature of the bottom topography in the Caspian Sea, it is customary to distinguish the Northern, Middle and Southern Caspian. The Northern Caspian is characterized by exceptionally shallow water, located completely within the shelf with average depths of 4-5 m. Even small changes in the level here at low coasts lead to significant fluctuations in the area of the water mirror, therefore, the boundaries of the sea in the northeastern part on small-scale maps are shown by a dotted line. The greatest depths (about 20 m) are observed only near the conditional border with the Middle Caspian, which is drawn along the line connecting Chechen Island (to the north of the Agrakhan Peninsula) with Tyub-Karagan Cape on the Mangyshlak Peninsula. In the relief of the bottom of the Middle Caspian, the Derbent depression stands out (the greatest depth is 788 m). The boundary between the Middle and South Caspian passes over the Apsheron threshold with depths up to 180 m along the line from Chilov Island (to the east of the Absheron Peninsula) to Cape Kuuli (Turkmenistan). The basin of the South Caspian is the most extensive area of the sea with the greatest depths, almost 2/3 of the waters of the Caspian Sea are concentrated here, 1/3 falls on the Middle Caspian, and less than 1% of the Caspian waters are located in the North Caspian due to shallow depths. In general, the shelf areas (the entire northern part and a wide strip along the eastern coast of the sea) predominate in the bottom relief of the Caspian Sea. The continental slope is most pronounced on western slope Derbent basin and almost along the entire perimeter of the South Caspian basin. On the shelf, terrigenous-shell sands, shells, and oolitic sands are common; deep-water areas of the bottom are covered with silty and silty sediments with a high content of calcium carbonate. In some areas of the bottom, Neogene bedrocks are exposed. Mirabilite accumulates in the Ka-ra-Bogaz-Gol Bay.

In tectonic terms, within the Northern Caspian, there are southern part The Caspian syneclise of the East European platform, which is framed in the south by the Astrakhan-Aktobe zone, composed of Devonian-Lower Permian carbonate rocks, occurring on a volcanic base and containing large deposits of oil and natural combustible gas. Paleozoic folded formations of the Donetsk-Caspian zone (or the Karpinsky ridge) are pushed onto the syneclise from the southwest, which is a protrusion of the basement of the young Scythian (in the west) and Turan (in the east) platforms, which are separated at the bottom of the Caspian Sea by the Agrakhan-Guryev fault (left shift) of northeast strike. The Middle Caspian mainly belongs to the Turan platform, and its southwestern margin (including the Derbent depression) is a continuation of the Terek-Caspian foredeep of the Greater Caucasus fold system. The sedimentary cover of the platform and trough, composed of Jurassic and younger sediments, contains oil and combustible gas deposits in local uplifts. The Apsheron Sill, which separates the Middle Caspian from the South, is a connecting link of the Cenozoic folded systems of the Greater Caucasus and the Kopetdag. The South Caspian Basin of the Caspian Sea with crust of oceanic or transitional type is filled with a thick (over 25 km) complex of Cenozoic sediments. Numerous large hydrocarbon deposits are concentrated in the South Caspian Basin.

Until the end of the Miocene, the Caspian Sea was a marginal sea of the ancient Tethys Ocean (since the Oligocene, the relic oceanic basin of the Paratethys). By the beginning of the Pliocene, it lost contact with the Black Sea. The Northern and Middle Caspians were drained, and the paleo-Volga valley stretched through them, the delta of which was located in the area of the Apsheron Peninsula. Delta sediments have become the main reservoir of oil and natural combustible gas deposits in Azerbaijan and Turkmenistan. In the late Pliocene, due to the Akchagyl transgression, the area of the Caspian Sea greatly increased and the connection with the World Ocean temporarily resumed. The waters of the sea covered not only the bottom of the modern depression of the Caspian Sea, but also the adjacent territories. In the Quaternary, transgressions (Absheron, Baku, Khazar, Khvalyn) alternated with regressions. The southern half of the Caspian Sea is located in a zone of increased seismic activity.

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

hydrological regime. Changes in the water balance of an enclosed sea strongly affect the change in the volume of water and the corresponding level fluctuations. Average long-term components of the water balance of the Caspian Sea for the 1900-90s (km 3 / cm layer): river runoff 300/77, precipitation 77/20, underground runoff 4/1, evaporation 377/97, runoff in Kara-Bogaz- Goal 13/3, which forms a negative water balance of 9 km 3 or 3 cm layer per year. According to paleogeographic data, over the past 2000 years, the range of fluctuations in the level of the Caspian Sea has reached at least 7 m. -29 m (the lowest position in the last 500 years). The sea surface area has decreased by more than 40 thousand km 2, which exceeds the area Sea of Azov. Since 1978, a rapid rise in level began, and by 1996 a mark of about -27 m relative to the level of the World Ocean was reached. In the modern era, fluctuations in the level of the Caspian Sea are determined mainly by fluctuations in climatic characteristics. Seasonal fluctuations in the level of the Caspian Sea are associated with the uneven flow of river flow (primarily the flow of the Volga), so the lowest level is observed in winter, the highest in summer. Short-term sharp changes in the level are associated with surge phenomena, they are most pronounced in shallow waters. northern regions and during storm surges can reach 3-4 m. Such surges cause flooding of significant coastal land areas. In the Middle and South Caspian, surge fluctuations in the level are on average 10-30 cm, under storm conditions - up to 1.5 m. The frequency of surges, depending on the area, is from one to 5 times a month, the duration is up to one day. In the Caspian, as in any closed reservoir, seiche fluctuations in the level are observed in the form of standing waves with periods of 4-9 hours (wind) and 12 hours (tidal). The magnitude of seiche fluctuations usually does not exceed 20–30 cm.

River flow in the Caspian Sea is distributed extremely unevenly. More than 130 rivers flow into the sea, which, on average, bring about 290 km 3 of fresh water per year. Up to 85% of the river flow falls on the Volga with the Urals and enters the shallow Northern Caspian. The rivers of the western coast - Kura, Samur, Sulak, Terek, etc. - give up to 10% of the runoff. Another approximately 5% of fresh water is brought to the South Caspian by the rivers of the Iranian coast. The eastern desert shores are completely devoid of constant fresh water.

The average speed of wind currents is 15-20 cm/s, the highest - up to 70 cm/s. In the North Caspian, the prevailing winds create a flow directed along the northwestern coast to the southwest. In the Middle Caspian, this current merges with the western branch of the local cyclonic circulation and continues to move along the western coast. At the Absheron Peninsula, the current bifurcates. Its part in the open sea flows into the cyclonic circulation of the Middle Caspian, and the coastal part goes around the shores of the South Caspian and turns to the north, joining the coastal current, enveloping the entire eastern coast. The average state of the movement of the Caspian surface waters is often disturbed due to the variability of wind conditions and other factors. Thus, in the northeastern shallow area, a local anticyclonic gyre can occur. Two anticyclonic eddies are often observed in the South Caspian. In the Middle Caspian, during the warm season, steady northwest winds create southward transport along the east coast. In light winds and during calm weather, the currents may have other directions.

Wind waves develop very strongly, since the prevailing winds have a large acceleration length. The excitement develops mainly in the northwestern and southeastern directions. Severe storms are observed in the open waters of the Middle Caspian, in the areas of the city of Makhachkala, the Apsheron Peninsula and the Mangyshlak Peninsula. Average Height waves of the greatest frequency of 1-1.5 m, with wind speeds of more than 15 m / s it increases to 2-3 m. .

The water temperature on the sea surface in January - February in the North Caspian is close to freezing (about -0.2 - -0.3 °C) and gradually rises southward to 11 °C off the coast of Iran. In summer, surface waters warm up to 23-28 °C everywhere, except for the eastern shelf of the Middle Caspian, where seasonal coastal upwelling develops in July-August and the water temperature on the surface drops to 12-17 °C. In winter, due to intense convective mixing, the water temperature changes little with depth. In summer, under the upper heated layer at the horizons of 20-30 m, a seasonal thermocline (a layer of sharp temperature change) is formed, separating deep cold waters from warm surface waters. In the bottom layers of water deep sea trenches All year round the temperature is 4.5-5.5 °C in the Middle Caspian and 5.8-6.5 °C in the South. The salinity in the Caspian Sea is almost 3 times lower than in the open areas of the World Ocean, and averages 12.8-12.9‰. It should be especially emphasized that salt composition Caspian water is not completely identical to the composition of ocean waters, which is explained by the isolation of the sea from the ocean. The waters of the Caspian Sea are poorer in sodium salts and chlorides, but richer in calcium and magnesium carbonates and sulfates due to the unique composition of salts entering the sea with river and underground runoff. The highest variability of salinity is observed in the Northern Caspian, where in the estuarine sections of the Volga and the Urals the water is fresh (less than 1‰), and as you move south, the salt content increases to 10-11‰ at the border with the Middle Caspian. The greatest horizontal salinity gradients are characteristic of the frontal zone between the sea and river waters. Differences in salinity between the Middle and South Caspian are small, salinity slightly increases from northwest to southeast, reaching 13.6‰ in the Turkmen Gulf (up to 300‰ in Kara-Bogaz-Gol). Salinity changes along the vertical are small and rarely exceed 0.3‰, which indicates a good vertical mixing water. Water transparency varies over a wide range from 0.2 m in the mouth areas of large rivers to 15-17 m in the central regions of the sea.

According to the ice regime, the Caspian Sea belongs to partially freezing seas. Ice conditions are observed annually only in the northern regions. The Northern Caspian is completely covered with sea ice, the Middle - partially (only in severe winters). Middle border sea ice passes along an arc, turned by a bulge to the north, from the Agrakhan Peninsula in the west to the Tyub-Karagan Peninsula in the east. Usually, ice formation begins in mid-November in the extreme northeast and gradually spreads to the southwest. In January, the entire Northern Caspian is covered with ice, mostly landfast ice (fixed). Drifting ice borders the fast ice with a strip 20-30 km wide. The average thickness of ice is from 30 cm at the southern border to 60 cm in the northeastern regions of the Northern Caspian, in hummocky heaps - up to 1.5 m. The destruction of the ice cover begins in the 2nd half of February. In severe winters, drifting ice is carried to the south, along the western coast, sometimes as far as the Absheron Peninsula. In early April, the sea is completely free of ice cover.

Research history. It is believed that modern name The Caspian Sea comes from the ancient tribes of the Caspians, who inhabited the coastal regions in the 1st millennium BC; other historical names: Hyrkan (Irkan), Persian, Khazar, Khvalyn (Khvalis), Khorezm, Derbent. The first mention of the existence of the Caspian Sea dates back to the 5th century BC. Herodotus was one of the first to argue that this reservoir is isolated, that is, it is a lake. In the works of Arab scientists of the Middle Ages, there is information that in the 13-16 centuries the Amu Darya partially flowed into this sea by one of the branches. The well-known numerous ancient Greek, Arabic, European, including Russian, maps of the Caspian Sea until the beginning of the 18th century did not reflect reality and were in fact arbitrary drawings. By order of Tsar Peter I, an expedition was organized in 1714-15 under the leadership of A. Bekovich-Cherkassky, who explored the Caspian Sea, in particular its eastern shores. The first map, on which the contours of the coasts are close to modern ones, was compiled in 1720 using astronomical definitions by Russian military hydrographers F. I. Soymonov and K. Verden. In 1731, Soimonov published the first atlas, and soon the first printed sailing direction of the Caspian Sea. A new edition of the maps of the Caspian Sea with corrections and additions was carried out by Admiral A. I. Nagaev in 1760. The first information on the geology and biology of the Caspian Sea was published by S. G. Gmelin and P. S. Pallas. Hydrographic research in the 2nd half of the 18th century was continued by I.V. Tokmachev, M.I. Voinovich, at the beginning of the 19th century - by A.E. Kolodkin, who was the first to perform instrumental compass survey of the coast. Published in 1807 new map of the Caspian Sea, compiled taking into account the latest inventories. In 1837, systematic instrumental observations of sea level fluctuations began in Baku. In 1847, the first complete description of the Kara-Bogaz-Gol Bay was made. In 1878, the General Map of the Caspian Sea was published, which reflected the results of the latest astronomical observations, hydrographic surveys, and depth measurements. In 1866, 1904, 1912–13, and 1914–15, under the leadership of N. M. Knipovich, expeditionary studies were carried out in the hydrology and hydrobiology of the Caspian Sea; in 1934, a Commission for the Comprehensive Study of the Caspian Sea was established under the Academy of Sciences of the USSR. A great contribution to the study of the geological structure and oil content of the Apsheron Peninsula and the geological history of the Caspian Sea was made by Soviet geologists I. M. Gubkin, D. V. and V. D. Golubyatnikovs, P. A. Pravoslavlev, V. P. Baturin, S. A . Kovalevsky; in the study of water balance and sea level fluctuations - B. A. Appolov, V. V. Valedinsky, K. P. Voskresensky, L.S. Berg. After the Great Patriotic War, systematic diversified studies were launched in the Caspian Sea, aimed at studying the hydrometeorological regime, biological conditions and the geological structure of the sea.

In the 21st century, two large scientific centers are engaged in solving the problems of the Caspian Sea in Russia. The Caspian Marine Research Center (CaspMNIC), established in 1995 by a decree of the Government of the Russian Federation, conducts research work in hydrometeorology, oceanography and ecology. The Caspian Research Institute of Fisheries (CaspNIRKH) traces its history from the Astrakhan Research Station [established in 1897, since 1930 the Volga-Caspian Scientific Fisheries Station, since 1948 the Caspian Branch of the All-Russian Research Institute of Fisheries and Oceanography, since 1954 the Caspian Research Institute of Marine Fisheries and Oceanography (KaspNIRO), modern name since 1965]. CaspNIRKh is developing the foundations for the conservation and rational use biological resources Caspian Sea. It consists of 18 laboratories and scientific departments - in Astrakhan, Volgograd and Makhachkala. It has a scientific fleet of more than 20 vessels.

Economic use. The natural resources of the Caspian Sea are rich and varied. Significant hydrocarbon reserves are being actively developed by Russian, Kazakh, Azerbaijani and Turkmen oil and gas companies. There are huge reserves of mineral self-saddle salts in the Kara-Bogaz-Gol Bay. The Caspian region is also known as a massive habitat for waterfowl and near-water birds. About 6 million migratory birds migrate through the Caspian Sea every year. In this regard, the Volga delta, Kyzylagadzh, Northern Cheleken and Turkmenbashi bays are recognized as sites of international rank under the Ramsar Convention. The estuarine sections of many rivers flowing into the sea have unique types of vegetation. The fauna of the Caspian Sea is represented by 1800 animal species, of which 415 species are vertebrates. More than 100 species of fish live in the sea and estuaries of rivers. are of commercial importance sea views- herring, sprat, gobies, sturgeons; freshwater - carp, perch; arctic "invaders" - salmon, white salmon. Major ports: Astrakhan, Makhachkala in Russia; Aktau, Atyrau in Kazakhstan; Turkmenbashi in Turkmenistan; Bandar Torkemen, Bandar Anzeli in Iran; Baku in Azerbaijan.

Ecological state. The Caspian Sea is under a powerful anthropogenic impact due to the intensive development of hydrocarbon deposits and the active development of fishing. In the 1980s, the Caspian Sea produced up to 80% of the world's sturgeon catch. Predatory catches of recent decades, poaching and a sharp deterioration in the ecological situation have put many valuable fish species on the brink of extinction. Habitat conditions have deteriorated not only for fish, but also for birds and marine animals (Caspian seal). The countries washed by the waters of the Caspian Sea face the problem of creating a set of international measures to prevent pollution of the aquatic environment and developing the most effective environmental strategy for the near future. A stable ecological state is noted only in parts of the sea remote from the coast.

Lit.: Caspian Sea. M., 1969; Complex studies of the Caspian Sea. M., 1970. Issue. 1; Gul K.K., Lappalainen T.N., Polushkin V.A. The Caspian Sea. M., 1970; Zalogin B. S., Kosarev A. N. Morya. M., 1999; International tectonic map Caspian Sea and its framing / Ed. V. E. Khain, N. A. Bogdanov. M., 2003; Zonn I. S. Caspian Encyclopedia. M., 2004.

M. G. Deev; V. E. Khain (geological structure of the bottom).