Which ocean does the Caspian Sea belong to? Temperature and salinity. Vertical mixing of water. Which countries is washed by the Caspian Sea?

In dry and hot climates, a large amount sea water evaporates, water molecules move into the air. So, every year such a thing is carried away from the surface of the Caspian Sea great amount water particles that together they would fill a bowl with a volume of several hundred cubic kilometers. This amount of water could fill ten such reservoirs as Kuibyshevskoye.

But can water from the surface of the sea get into the bottom layers of the Caspian Sea, to a depth of 900-980 meters?

This is possible provided that the density of the surface layers of water is greater than the density of the bottom layers.

It is known that the density of sea water depends on salinity and temperature. The more salts the water contains, the denser it is, and therefore heavier. Water with high temperature less dense than cold water. Only at low temperatures (about 0-4° Celsius) is the opposite relationship given, when water, heating up, becomes more dense.

High salinity of the surface layers of the sea is created in the hot season, when the water evaporates strongly, but the salt remains in the sea. At this time, the salinity of surface waters turns out to be no less, and even slightly greater than the salinity of deep and near-bottom layers.

The temperature of surface waters in the warm season is the same everywhere, about 25-28°, that is, five times higher than at a depth of 150-200 meters. With the onset of the cold season, the temperature of the surface layers decreases and during a certain period it turns out to be 5-6° above zero.

The temperature of the bottom and deep (deeper than 150-200 m) layers of the Caspian Sea is the same (5-6°), practically unchanged throughout the year.

Under these conditions, it is possible for denser surface cold and highly saline water to sink into the bottom layers.

Only in the southern regions of the Caspian Sea the surface water temperature, as a rule, does not drop to 5-6° even in winter. And, although the descent of surface water into depth cannot directly occur in these areas, water that has descended from the surface to more depth is brought here by deep currents. northern parts seas.

A similar phenomenon is observed in the eastern part of the border zone between the Middle and Southern Caspian Seas, where cooled surface waters descend along the southern slope of the border underwater threshold and then follow a deep current into the southern regions of the sea.

This widespread mixing of surface and deep waters is confirmed by the fact that oxygen was found at all depths of the Caspian Sea.

Oxygen can only reach depths with the surface layers of water, where it comes directly from the atmosphere or as a result of photosynthesis.

If there were no continuous supply of oxygen to the bottom layers, it would quickly be absorbed by animal organisms there or spent on the oxidation of soil organic matter. Instead of oxygen, the bottom layers would be saturated with hydrogen sulfide, which is what is observed in the Black Sea. The vertical circulation in it is so weak that oxygen in sufficient quantities does not reach the depth, where hydrogen sulfide is formed.

Although oxygen has been found at all depths of the Caspian Sea, it is not in the same quantity in different seasons of the year.

The water column is richest in oxygen in winter. The harsher the winter, that is, the lower the surface temperature, the more intense the aeration process occurs, which reaches the deepest parts of the sea. Conversely, several warm winters in a row can cause the appearance of hydrogen sulfide in the bottom layers and even the complete disappearance of oxygen. But such phenomena are temporary and disappear during the first more or less severe winter.

The upper water column to a depth of 100-150 meters is especially rich in dissolved oxygen. Here the oxygen content ranges from 5 to 10 cubic meters. cm in liter. At depths of 150-450 m, there is much less oxygen - from 5 to 2 cubic meters. cm in liter.

Below 450 m there is very little oxygen and life is represented very sparsely - several species of worms and mollusks, small crustaceans.

Mixing of water masses is also caused by surge phenomena and waves.

Waves, currents, winter vertical circulation, surges, surges act constantly and are important factors mixing water It is not surprising, therefore, that no matter where we take a water sample in the Caspian Sea, everywhere chemical composition hers will be permanent. If there were no mixing of waters, all living organisms great depths died out. Life would only be possible in the photosynthetic zone.

Where the waters mix well and this process occurs quickly, for example in shallow areas of the seas and oceans, life is richer.

The constancy of the salt composition of the water of the Caspian Sea is a general property of the waters of the World Ocean. But this does not mean that the chemical composition of the Caspian Sea is the same as in the ocean or in any sea connected to the ocean. Consider a table showing the salt content in the waters of the ocean, the Caspian Sea and the Volga.

	Carbonates (CaCO 3)	Sulfates CaSO 4, MgSO 4	Chlorides NaCl, KCl, MgCl 2	Average water salinity ‰
Ocean	0,21	10,34	89,45
Caspian Sea	1,24	30,54	67,90	12,9
Volga river	57,2	33,4

The table shows that ocean water has very little in common with river water in terms of salt composition. In terms of salt composition, the Caspian Sea occupies an intermediate position between the river and the ocean, which is explained by the great influence of river runoff on the chemical composition of Caspian water. The ratio of salts dissolved in water Aral Sea, is closer to the salt composition of river water. This is understandable, since the ratio of the volume of river flow to the volume of water in the Aral Sea is much greater than for the Caspian Sea. A large number of sulphate salts in the Caspian Sea gives its water a bitter-salty taste, distinguishing it from the waters of the oceans and the seas connected to them

The salinity of the Caspian Sea continuously increases towards the south. In the pre-estuary space of the Volga, a kilogram of water contains hundredths of a gram of salts. In the eastern regions of the Southern and Middle Caspian Sea, salinity reaches 13-14‰

Salt concentration in Caspian water small. So, in this water you can dissolve almost twenty times more salts than are present in it.

B.A. Shlyamin. Caspian Sea. 1954

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Is it correct to call the Caspian Sea a sea?

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

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

So, after all, the Caspian Sea is a lake? That's Wikipedia says it And the Great Soviet Encyclopedia answers that no one has yet been able to give an exact definition of this issue - “There is no generally accepted classification.”

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

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

Due to its geographical location, the Caspian Sea itself, unlike 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 19th century. the first treaties were concluded between Russia and Persia: Gulistan (1813) 4 and Turkmanchay (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 military fleet in the Caspian sea. Russian and Persian merchants were allowed to trade freely 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, the new Russian government that came to power renounced its exclusive military presence in the Caspian Sea. The treaty 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 the common use of the parties: both states were granted equal rights of free navigation, with the exception of 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 agreement was signed, the parties to which were new subjects of international law - the Soviet Union and Iran, which acted under a new name. The parties confirmed the provisions of the 1921 agreement, but introduced into the agreement a new concept for the Caspian Sea - a 10-mile fishing zone, which limited the spatial limits of this fishery for its participants. This was done in order to control and preserve 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 agreement between the USSR and Iran on trade and navigation in the Caspian Sea. The reason for this was the concern of the Soviet side, caused by Germany’s interest in intensifying its trade ties with Iran and the danger of using the Caspian Sea as one of the stages of the transit route. The agreement between the USSR and Iran 10 signed in 1940 protected the Caspian Sea from such a prospect: it repeated the main provisions of previous agreements, which provided for the presence of ships of only these two Caspian states in its waters. 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 a large number of new problems, the problem of the Caspian Sea arose. Instead of two states - the USSR and Iran, which previously bilaterally resolved all emerging issues of maritime navigation, fishing and the use of 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 as successor, the other three are new states: Azerbaijan, Kazakhstan, Turkmenistan. They had access to the Caspian Sea before, but only as republics of the USSR, and not as independent states. Now, having become independent and sovereign, they have the opportunity to participate on equal terms with Russia and Iran in discussions and decision-making in considering all the issues mentioned above. This was also reflected in the attitude of these states towards the Caspian Sea, since all five states that had access to it showed equal interest in using 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 became the subject of the most heated and protracted negotiations for a long time. But not only them.

In addition to the presence of rich mineral resources, the waters of the Caspian Sea are home to about 120 species and subspecies of fish; here is the global gene pool of sturgeon, the catch of which until recently accounted for 90% of the total world catch.

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

And yet, the main object of attention of the Caspian states is its mineral resources - oil and natural gas, which each of them can lay claim to within the boundaries that must be determined by them collectively on the basis of international law. And to do this, they will have to divide between themselves both the waters of 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 starting widespread mining of Caspian mineral resources 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 resolve it, and there is no agreement yet among them. But at the same time, each of them strives to quickly begin production of Caspian oil and natural gas and make their sale abroad a constant source of funds to form their budget.

Therefore, oil companies of Azerbaijan, Kazakhstan and Turkmenistan, without waiting for the end of the settlement of existing disagreements over the territorial division of the Caspian Sea, 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 to 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 to the territorial division of its water area and bottom or develop their own for this case.

Kazakhstan advocated recognition of the Caspian Sea by the sea. Such recognition will make it possible to apply 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 to the division of the Caspian Sea. This would allow coastal states to gain sovereignty over the subsoil of the territorial sea (Article 2) and exclusive rights to the exploration and development of resources on the continental shelf (Article 77). But the Caspian Sea cannot be called a sea from the standpoint of the 1982 UN Convention on the Law of the Sea, since this body of water is closed and has no natural connection with the world ocean.

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

In the agreements between the USSR and Iran, the Caspian Sea was considered as a border lake. With the Caspian Sea being given the legal status of a “lake”, it is expected to be divided into sectors, as is done in relation to border lakes. But there is no norm in international law obliging states to do exactly this: division into sectors is an established practice.

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

In the literature, a proposal was made to give the Caspian Sea the status of a “sui generis” lake, and in this case we are talking about the special international legal status of such a lake and its special regime. A regime implies the joint development by states of their own rules for the use of its resources.

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

Currently, all Caspian states recognize that the modern legal regime was established by the established practice of its use, but now the Caspian Sea is in actual common use not by two, but by five states. Even at a meeting of foreign ministers held in Ashgabat on November 12, 1996, the Caspian states confirmed that the status of the Caspian Sea can be changed only with the consent of all five coastal states. This was later 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 during numerous Caspian negotiations, conferences and four summits of the Caspian states (Ashgabat summit on April 23-24, 2002, Tehran summit on October 16, 2007, Baku summit on November 18, 2010 and Astrakhan on September 29, 2014) agreement was reached by the Caspian countries failed to achieve this.

So far, cooperation at the bilateral and trilateral level has proven to be more productive. Back in May 2003, Russia, Azerbaijan and Kazakhstan entered into an agreement on the junction point of the demarcation lines of adjacent sections of the Caspian Sea bottom, 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 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, it was announced that the seabed would be delimited between adjacent and opposite parties along a modified median line based on the principle of fairness and agreement of the parties. At the bottom of the site, states have sovereign rights, but their common use of the water surface is preserved.

Iran perceived this agreement as separate and in violation of previous Treaties with the USSR in 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 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 comes 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, involves dividing only the bottom between the coastal states, and considering the water surface to be common and open to all coastal countries.

The existing options for delimiting the Caspian Sea, including those mentioned above, are possible only if there is good political will of the parties. Azerbaijan and Kazakhstan have clearly expressed their position from the very beginning of the multilateral consultation process. Azerbaijan considers the Caspian Sea to be a lake and therefore should be divided. Kazakhstan proposes to consider the Caspian Sea a closed sea, citing 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 Sea, but foreign companies already developing resources off the coast of Turkmenistan influenced the policies of its president, who began to object to the establishment of a condominium regime, supporting the position of dividing the sea.

The first of the Caspian states to begin to use the hydrocarbon riches of the Caspian Sea under new conditions was Azerbaijan. After the conclusion of the “Deal of the Century” in September 1994, Baku expressed a desire to declare the adjacent sector an integral part of its territory. This provision was 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 has expressed fears that this would open access to the Caspian Sea to countries in other regions. Azerbaijan agreed to a compromise. The 2002 Agreement between the Russian Federation and Azerbaijan on the delimitation of adjacent areas of the Caspian Sea established a provision 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 has expressed a desire to completely divide the Caspian Sea, Iran proposes to leave its subsoil and water for joint use, but does not object to the option of dividing the Caspian Sea 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. Moscow has long insisted on establishing a condominium, but wanting to build a long-term policy with its neighbors, who were not interested in considering the Caspian Sea as the property of five coastal states, it changed its position. This then prompted the states to begin a new stage of negotiations, at the end of which the above Agreement was signed in 1998, where Russia stated that it was “ripe” for the division of the Caspian Sea. Its main principle was the position “common water - divide the bottom.”

Taking into account the fact that some Caspian states, namely Azerbaijan, Kazakhstan and Russia, have reached agreements on the conditional delimitation of spaces in the Caspian Sea, 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 the joint use of the surface reservoir for navigation and fishing.

However, the lack of complete clarity and unity in the position of all coastal countries prevents the Caspian states themselves from developing oil production. And oil is of key importance to them. There is no clear data regarding their reserves in the Caspian Sea. According to the US Energy Information Agency in 2003, the Caspian Sea ranked second in oil reserves and third in gas reserves. The data from 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 geopolitical significance of the region, which is associated with the foreign policy plans of the US and the EU, became a factor in the distortion of the data. Zbigniew Brzezinski expressed the opinion back in 1997 that this region is the “Eurasian Balkans”.

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

According to one hypothesis, the Caspian Sea (among the ancient Slavs – the Khvalynsk Sea) received its name in honor of the Caspian tribes who lived BC on its southwestern coast.

The Caspian Sea washes the shores of five states: Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan.

The Caspian Sea is elongated in the meridional direction and is located between 36°33΄ and 47°07΄ N latitude. and 45°43΄ and 54°03΄ E. (without Kara-Bogaz-Gol Bay). The length of the sea along the meridian is about 1200 km; average width – 310 km. The northern coast of the Caspian Sea is bordered by the Caspian lowland, the eastern coast by the deserts of Central Asia; in the west the Caucasus Mountains approach the sea, in the south the Elburz ridge stretches near the coast.

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

The Caspian Sea is traditionally divided into three large parts: the Northern (24% of the sea area), the Middle (36%) and the Southern Caspian (40%), which differ significantly in morphology and regime, as well as the large and isolated Kara-Bogaz-Gol Bay. The northern, shelf part of the sea is shallow: its average depth is 5–6 m, maximum depths are 15–25 m, the volume is less than 1% of the total water mass of the sea. The Middle Caspian is an isolated basin with an area of maximum depths in the Derbent depression (788 m); its average depth is about 190 m. In the South Caspian, the average and maximum depths are 345 and 1025 m (in the South Caspian depression); 65% of the sea's water mass is concentrated here.

There are about 50 islands in the Caspian Sea with a total area of approximately 400 km2; the main ones are Tyuleniy, Chechen, Zyudev, Konevsky, Dzhambaysky, Durneva, Ogurchinsky, Apsheronsky. The length of the coastline is approximately 6.8 thousand km, with islands – up to 7.5 thousand km. The shores of the Caspian Sea are diverse. In the northern and eastern parts they are quite rugged. Here are the large bays of Kizlyarsky, Komsomolets, Mangyshlaksky, Kazakhsky, Kara-Bogaz-Gol, Krasnovodsky and Turkmensky, many bays; off the west coast - Kyzylagachsky. The largest peninsulas are Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak, Krasnovodsky, Cheleken and Apsheronsky. The most common shores are accumulative; areas with abrasion shores are found along the contour of the Middle and Southern Caspian Sea.

Over 130 rivers flow into the Caspian Sea, the largest of which are the Volga , Ural, Terek, Sulak, Samur, Kura, Sefidrud, Atrek, Emba (its flow enters the sea only in high-water years). Nine rivers have deltas; the largest are located at the mouths of the Volga and Terek.

The main feature of the Caspian Sea, as an endorheic reservoir, is instability and a wide range of long-term fluctuations in its level. This most important hydrological feature of the Caspian Sea has a significant impact on all its other hydrological characteristics, as well as on the structure and regime of river mouths and coastal zones. In the Caspian Sea level varied in the range of ~200 m: from -140 to +50 m BS; at -34 to -20 m BS. From the first third of the 19th century. and until 1977, sea level dropped by about 3.8 m - to the lowest level in the last 400 years (-29.01 m BS). In 1978–1995 The level of the Caspian Sea rose by 2.35 m and reached -26.66 m BS. Since 1995, a certain downward trend in level has been dominant - to -27.69 m BS in 2013.

During major events, the northern coast of the Caspian Sea shifted to the Samara Luka on the Volga, and perhaps further. During maximum transgressions, the Caspian Sea turned into a drainage lake: excess water flowed through the Kuma-Manych depression into the Sea of Azov and further into the Black Sea. During extreme regressions, the southern coast of the Caspian Sea shifted to the Absheron threshold.

Long-term fluctuations in the level of the Caspian Sea are explained by changes in the structure of the water balance of the Caspian Sea. Sea level rises when the incoming part of the water balance (primarily the water flow of rivers) increases and exceeds the outgoing part, and decreases if the influx of river water decreases. The total water flow of all rivers averages 300 km 3 /year; while the five largest rivers account for almost 95% (the Volga gives 83%). During the period of the lowest sea level, in 1942–1977, the river flow was 275.3 km 3 /year (of which 234.6 km 3 /year was the Volga runoff), precipitation - 70.9, underground flow - 4 km 3 /year, and evaporation and outflow into the Kara-Bogaz-Gol Bay are 354.79 and 9.8 km 3 /year. During the period of intense sea level rise, in 1978–1995, - respectively 315 (Volga - 274.1), 86.1, 4, 348.79 and 8.7 km 3 /year; in the modern period - 287.4 (Volga - 248.2), 75.3, 4, 378.3 and 16.3 km 3 /year.

Intra-annual changes in the level of the Caspian Sea are characterized by a maximum in June–July and a minimum in February; the range of intra-annual level fluctuations is 30–40 cm. Surge level fluctuations occur throughout the sea, but they are most significant in the northern part, where, with maximum surges, the level can rise by 2–4.5 m and the edge “retreat” by several tens kilometers inland, and during surges it will drop by 1–2.5 m. Seiche and tidal level fluctuations do not exceed 0.1–0.2 m.

Despite the relatively small size of the reservoir, there is strong excitement in the Caspian Sea. The highest wave heights in the Southern Caspian Sea can reach 10–11 m. Wave heights decrease in the direction from south to north. Storm waves can develop at any time of the year, but they are more frequent and more dangerous in the cold half of the year.

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

Water temperature is subject to significant latitudinal and seasonal changes. In winter, it varies from 0–0.5 o C at the ice edge in the north of the sea to 10–11 o C in the south. In summer, the water temperature in the sea averages 23–28 o C, and in shallow coastal waters in the Northern Caspian Sea it can reach 35–40 o C. At depths, a constant temperature is maintained: deeper than 100 m it is 4–7 o C.

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

Water salinity changes especially sharply in the northern part of the sea: from 0.1‰ at the mouth shores of the Volga and Ural to 10–12‰ on the border with the Middle Caspian. In the Northern Caspian Sea, the temporal variability of water salinity is also great. In the middle and southern parts of the sea, salinity fluctuations are small: it is generally 12.5–13.5‰, increasing from north to south and from west to east. The highest water salinity is in the Kara-Bogaz-Gol Bay (up to 300‰). With depth, the salinity of water increases slightly (by 0.1–0.3‰). The average salinity of the sea is about 12.5‰.

More than a hundred species of fish live in the Caspian Sea and the mouths of the rivers flowing into it. There are Mediterranean and Arctic invaders. The fish species are goby, herring, salmon, carp, mullet and sturgeon. The latter include five species: sturgeon, beluga, stellate sturgeon, thorn and sterlet. The sea can produce up to 500–550 thousand tons of fish annually, if overfishing is not allowed. Of the marine mammals, the endemic Caspian seal lives in the Caspian Sea. 5–6 million waterfowl migrate through the Caspian region annually.

The economy of the Caspian Sea is associated with oil and gas production, shipping, fishing, seafood, various salts and minerals (Kara-Bogaz-Gol Bay), and the use of recreational resources. The explored oil resources in the Caspian Sea amount to about 10 billion tons, the total resources of oil and gas condensate are estimated at 18–20 billion tons. Oil and gas production is carried out on an ever-increasing scale. The Caspian Sea is also used by water transport, including along the river-sea and sea-river routes. The main ports of the Caspian Sea: Astrakhan, Olya, Makhachkala (Russia), Aktau, Atyrau (Kazakhstan), Baku (Azerbaijan), Noushehr, Bandar-Anzeli, Bandar-Torkemen (Iran) and Turkmenbashi (Turkmenistan).

Economic activities and hydrological features of the Caspian Sea create a number of serious environmental and water management problems. Among them: anthropogenic pollution of river and sea waters (mainly with petroleum products, phenols and surfactants), poaching and reduction of fish stocks, especially sturgeon; damage to the population and coastal economic activities due to large-scale and rapid changes in the level of the reservoir, the impact of numerous dangerous hydrological phenomena and hydrological-morphological processes.

The total economic damage for all Caspian countries associated with the rapid and significant recent rise in the level of the Caspian Sea, the flooding of part of the coastal land, and the destruction of coastlines and coastal structures, amounted to an estimated amount of 15 to 30 billion US dollars. Urgent engineering measures were required to protect the coast.

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

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

The Caspian Sea is the object of many years of research by specialists from all Caspian states. Such domestic organizations as the State Oceanographic Institute, the Institute of Oceanology of the Russian Academy of Sciences, the Hydrometeorological Center of Russia, the Caspian Research Institute of Fisheries, the Faculty of Geography of Moscow State University, etc. took an active part in the study of the Caspian Sea.

The territory of Russia is washed by twelve seas belonging to the basins of three oceans. But one of these seas - the Caspian - is often called a lake, which sometimes confuses people who have little understanding of geography.

Meanwhile, it is really more correct to call the Caspian a lake rather than a sea. Why? Let's figure it out.

A little geography. Where is the Caspian Sea located?

Occupying an area that exceeds 370,000 square kilometers, the Caspian Sea stretches from north to south, dividing the spaces of Europe and Asia with its water surface. Its coastline belongs to five different countries: Russia, Kazakhstan, Azerbaijan, Turkmenistan and Iran. Geographers conventionally divide its water area into three parts: the Northern (25% of the area), the Middle (36% of the area) and the Southern Caspian (39% of the area), which differ in climate, geological conditions and natural features. The coastline is predominantly flat, indented by river channels, covered with vegetation, and in the northern part, where the Volga flows into the Caspian Sea, it is also swampy.

The Caspian Sea has about 50 large and small islands, about one and a half dozen bays and six large peninsulas. In addition to the Volga, approximately 130 rivers flow into it, and nine rivers form fairly wide and branched deltas. The annual drainage of the Volga is about 120 cubic kilometers. Together with other large rivers - Terek, Ural, Emba and Sulak - this accounts for up to 90% of the total annual flow into the Caspian Sea.

Why is the Caspian called a lake?

The main feature of any sea is the presence of straits connecting it to the ocean. The Caspian Sea is a closed or closed reservoir that receives river water, but is not connected to any ocean.

Its water contains a very small amount of salt compared to other seas (about 0.05%) and is considered slightly salty. Due to the absence of at least one strait connecting to the ocean, the Caspian Sea is often called the largest lake in the world, since the lake is a completely enclosed body of water that is fed only by river water.

The waters of the Caspian Sea are not subject to international maritime laws, and its waters are divided between all countries that are adjacent to it, in proportion to the coastline.

Why is the Caspian called a sea?

Despite all of the above, most often in geography, as well as in international and internal documents, the name “Caspian Sea” is used, and not “Caspian Lake”. First of all, this is explained by the size of the reservoir, which is much more typical for the sea than for the lake. Even, which is much smaller in area than the Caspian Sea, is often called a sea by local residents. There are no other lakes in the world whose shores belong simultaneously to five different countries.

In addition, you should pay attention to the structure of the bottom, which near the Caspian Sea has a pronounced oceanic type. Once upon a time, the Caspian Sea most likely connected with the Mediterranean, but tectonic processes and drying out separated it from the World Ocean. There are more than fifty islands in the Caspian Sea, and the area of some of them is quite large, even by international standards they are considered large. All this allows us to call the Caspian a sea, and not a lake.

origin of name

Why is this sea (or lake) called the Caspian? The origin of any name is often connected with the ancient history of the area. Different peoples who lived on the shores of the Caspian called it differently. More than seventy names of this reservoir have been preserved in history - it was called the Hyrcanian, Derbent, Sarai Sea, etc.

Iranians and Azerbaijanis still call it the Khazar Sea. It began to be called Caspian after the name of the ancient tribe of nomadic horse breeders who lived in the steppes adjacent to its coast - the numerous Caspian tribe. It was they who gave the name to the largest lake on our planet - the Caspian Sea.

, 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 approximately 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 according to physical and geographical conditions into 3 parts - Northern Caspian, Middle Caspian and Southern Caspian. The conditional border between the Northern and Middle Caspian runs along the line of the island. Chechen - Cape Tyub-Karagansky, between the Middle and Southern Caspian Sea - along the line of the island. Residential - Cape Gan-Gulu. The area of the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

Coast of the Caspian Sea

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
Khara-Zira
Sengi-Mugan
Chygyl

Bays of the Caspian Sea

Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, the length of the coastline is about 1930 kilometers
Kazakhstan - in the north, northeast 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 southwest, the length of the coastline is about 800 kilometers

Cities on the Caspian Sea coast

On the Russian coast are the cities of 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 fluctuations in water levels. At 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 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.

Water level fluctuations

Vegetable world

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

History of the Caspian Sea

Origin of the Caspian Sea

Anthropological and cultural history of the Caspian Sea

Finds in the Khuto Cave off the southern coast of the Caspian Sea indicate that man lived in these areas approximately 75 thousand years ago. The first mentions of the Caspian Sea and the tribes living on its coast are found in Herodotus. Around the V-II centuries. BC e. Saka tribes lived on the Caspian coast. Later, during the period of settlement of the Turks, in the period of the 4th-5th centuries. n. e. Talysh tribes (Talysh) lived here. According to ancient Armenian and Iranian manuscripts, Russians sailed the Caspian Sea from the 9th-10th centuries.

Research of the Caspian Sea

Research of the Caspian Sea was started by Peter the Great, when, on his order, an expedition was organized in 1714-1715 under the leadership of A. Bekovich-Cherkassky. In the 1720s, hydrographic research was continued by the expedition of Karl von Werden and F. I. Soimonov, and later by I. V. Tokmachev, M. I. Voinovich and other researchers. At the beginning of the 19th century, instrumental surveys of the shores were carried out by I. F. Kolodkin, in the mid-19th century. - instrumental geographical survey under the direction of N. A. Ivashintsev. Since 1866, for more than 50 years, expeditionary research on the hydrology and hydrobiology of the Caspian Sea was carried out under the leadership of N. M. Knipovich. In 1897, the Astrakhan Research Station was founded. In the first decades of Soviet power, geological research by I.M. Gubkin and other Soviet geologists was actively carried out in the Caspian Sea, mainly aimed at searching for oil, as well as research into the study of water balance and level fluctuations in 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. Proven oil resources in the Caspian Sea are about 10 billion tons, total oil and gas condensate resources are estimated at 18-20 billion tons.

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

Shipping

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

Fishing and seafood production

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

Recreational resources

The natural environment of the Caspian coast with sandy beaches, mineral waters and healing mud in the coastal zone creates good conditions for recreation and treatment. At the same time, in terms of the degree of development of resorts and the 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. In Azerbaijan, the resort area in the Baku region is actively developing. 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, and holidays in the sanatoriums of the villages of Bilgah and Zagulba are very popular. A resort area is also being developed in Nabran, in northern Azerbaijan. However, high prices, a generally low level of service and a lack of advertising lead to the fact that there are almost no foreign tourists at the Caspian resorts. The development of the tourism industry in Turkmenistan is hampered by a long-term policy of isolation, in Iran - Sharia laws, due to which mass holidays of foreign tourists on the Caspian coast of Iran are impossible.

Ecological problems

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

International status of the Caspian Sea

Legal status of the Caspian Sea

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

In relation to the Caspian Sea, the key is the physical-geographical circumstance that it is a closed inland body of water that does not have a natural connection with the World Ocean. Accordingly, the norms and concepts of international maritime law, in particular, the provisions of the UN Convention on the Law of the Sea of 1982, should not be automatically applied to the Caspian Sea. Based on this, in relation to the Caspian Sea it would be unlawful to apply such concepts as “territorial sea”, “exclusive 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 vessels flying the flag of non-Caspian states sailing in its waters.

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

Delineation of sections of the Caspian seabed for subsoil use

The Russian Federation concluded 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 thereto dated May 13, 2002), an agreement with Azerbaijan on delimiting adjacent areas 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 demarcation lines of adjacent sections of the bottom of the Caspian Sea (dated May 14, 2003), which established the geographical coordinates of the dividing lines limiting the sections of the bottom within which the parties exercise their sovereign rights in the field of exploration and production of mineral resources.