Caspian Sea Caspian. Caspian Sea: report

The Caspian Sea is located on the continent of Eurasia. What is surprising is that the Caspian Sea, with an area of ​​370 thousand square kilometers, is actually the most big lake, since it has no communication with the ocean. Although it is difficult to call it a lake, because the composition of the water, flora and fauna are similar to those of the sea. The salinity of the water is close to oceanic (from 0.05% to 13%).

Photo: Seagulls on the shores of the Caspian Sea.

About 50 million years ago, the Tethys Sea was located on the territory of Eastern Europe, which, when drying up, was divided into several large bodies of water - the Caspian, Black and Mediterranean seas.

Thanks to mineral waters and therapeutic mud The Caspian Sea has great recreational and health potential. Therefore, there is an increase in the popularity of the coasts of Turkmenistan, Iran, Azerbaijan and Russian Dagestan among tourists.

Particularly popular resort area in the Baku region, where it is located popular resort in Amburan, as well as the area of ​​the village of Nardaran, sanatoriums in the villages of Zagulba and Bilgah. In the north of Azerbaijan, the resort in Nabran is gaining popularity.

Unfortunately, tourism in Turkmenistan is poorly developed, which is due to the policy of isolation. And in Iran, Sharia law prohibits vacationing foreign tourists on the coast.

But if you decide to relax on the Caspian Lake, then you will enjoy walking through protected areas; you will see extraordinary floating islands, various plants and animals that live in fresh and salt waters.

There is a greater variety of ways to have a good time throughout the year. For example, you can go on boat cruises, go fishing or waterfowl hunting, or you can simply enjoy the healing waters, looking at seals and a variety of birds. The protected areas of the sea coast are very beautiful, for example the Astrakhan International Biosphere Reserve and the Volga delta with lotus fields.

A special feature of the Caspian zone is the oriental flavor with hookah and mesmerizing dances. Traditional music will delight your ears, and East Asian cuisine will satisfy your hunger.

See where the Caspian Sea is located on the world map.

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Video: Caspian Sea. Storm. 07/08/2012.


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, Canadian lake The top one is also a huge area, like 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. Yes and Big Soviet Encyclopedia replies 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.

In my own way geographical location The Caspian Sea itself, unlike the land territories surrounding it, has not been the object of any targeted attention on the part of 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 when the crews of Iranian ships could include citizens of third countries using the service for unfriendly purposes (Article 7). Treaty of 1921 maritime border did not provide 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 Iran10 signed in 1940 protected the Caspian Sea from such a prospect: it repeated the main provisions of previous agreements, which provided for the presence in its waters of 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 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.

Besides having 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 banks there are such large sea ​​ports, like Russian Astrakhan, the capital of Azerbaijan Baku, Turkmen Turkmenbashi, Iranian Anzeli and Kazakh Aktau, between which trade, cargo and passenger maritime 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, 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, primarily 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 their ranks. 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, in this capacity, starting 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 sector adjacent to it integral part 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 states to begin new stage 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”.

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. Shared with others large rivers– Terek, Ural, Emba and Sulak – this accounts for up to 90% of the total annual runoff 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 drainless body of water 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 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, local residents often called the sea. 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 associated with ancient history terrain. 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.

V. N. MIKHAILOV

The Caspian Sea is the largest closed lake on the planet. This body of water is called the sea for its huge size, brackish water and a regime similar to the sea. The level of the Caspian Sea-lake lies much lower than the level of the World Ocean. At the beginning of 2000, it was around -27 abs. m. At this level, the area of ​​the Caspian Sea is ~ 393 thousand km2 and the volume of water is 78,600 km3. The average and maximum depths are 208 and 1025 m, respectively.

The Caspian Sea stretches from south to north (Fig. 1). The Caspian Sea washes the shores of Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran. The reservoir is rich in fish, its bottom and shores are rich in oil and gas. The Caspian Sea has been studied quite well, but many mysteries remain in its regime. The most characteristic feature of a reservoir is the instability of the level with sharp drops and rises. The last increase in the level of the Caspian Sea occurred before our eyes from 1978 to 1995. It gave rise to many rumors and speculation. Numerous publications appeared in the press talking about catastrophic floods and an environmental disaster. They often wrote that the rise in the level of the Caspian Sea led to the flooding of almost the entire Volga delta. What is true in the statements made? What is the reason for this behavior of the Caspian Sea?

WHAT HAPPENED TO THE CASPIAN IN THE XX CENTURY

Systematic observations of the level of the Caspian Sea began in 1837. In the second half of the 19th century, the average annual values ​​of the Caspian Sea level were in the range from – 26 to – 25.5 abs. m and had a slight downward trend. This trend continued into the 20th century (Fig. 2). In the period from 1929 to 1941, sea level dropped sharply (by almost 2 m - from - 25.88 to - 27.84 abs. m). In subsequent years, the level continued to fall and, having decreased by approximately 1.2 m, reached in 1977 the lowest level during the observation period - 29.01 abs. m. Then the sea level began to rise rapidly and, having risen by 2.35 m by 1995, reached 26.66 abs. m. In the next four years, the average sea level dropped by almost 30 cm. Its average levels were - 26.80 in 1996, - 26.95 in 1997, - 26.94 in 1998 and - 27.00 abs. m in 1999.

The decrease in sea level in 1930-1970 led to the shallowing of coastal waters, the extension of the coastline towards the sea, and the formation of wide beaches. The latter was perhaps the only positive consequence of the drop in level. There were significantly more negative consequences. As the level dropped, the areas of feeding grounds for fish stocks in the northern Caspian Sea decreased. The shallow-water estuarine coastal area of ​​the Volga began to quickly become overgrown with aquatic vegetation, which worsened the conditions for the passage of fish to spawn in the Volga. Fish catches have sharply decreased, especially valuable species: sturgeon and sterlet. Shipping began to suffer due to the fact that the depths in the approach channels decreased, especially near the Volga delta.

The rise in levels from 1978 to 1995 was not only unexpected, but also led to even greater negative consequences. After all, both the economy and the population of coastal areas have already adapted to the low level.

Many sectors of the economy began to suffer damage. Significant territories were in the zone of flooding and inundation, especially in the northern (plain) part of Dagestan, in Kalmykia and Astrakhan region. The cities of Derbent, Kaspiysk, Makhachkala, Sulak, Kaspiysky (Lagan) and dozens of other smaller settlements suffered from the rise in level. Significant areas of agricultural land have been flooded and submerged. Roads and power lines, engineering structures of industrial enterprises and public utilities are being destroyed. A threatening situation has developed with fish farming enterprises. Abrasion processes in the coastal zone and the influence of seawater surges have intensified. IN last years seaside flora and fauna and coastal zone The Volga delta suffered significant damage.

Due to the increase in depth in the shallow waters of the Northern Caspian and the reduction in the areas occupied by aquatic vegetation in these places, the conditions for the reproduction of stocks of anadromous and semi-anadromous fish and the conditions for their migration to the delta for spawning have somewhat improved. However, the predominance of negative consequences from rising sea levels has led to talk of an environmental catastrophe. The development of measures to protect national economic facilities and settlements from the advancing sea began.

HOW UNUSUAL IS THE CURRENT BEHAVIOR OF THE CASPIAN SEA?

Research into the life history of the Caspian Sea can help answer this question. Of course, there are no direct observations of the past regime of the Caspian Sea, but there is archaeological, cartographic and other evidence for historical time and the results of paleogeographic studies covering a longer period.

It has been proven that during the Pleistocene (the last 700-500 thousand years), the level of the Caspian Sea underwent large-scale fluctuations in the range of about 200 m: from -140 to + 50 abs. m. During this period of time, four stages are distinguished in the history of the Caspian Sea: Baku, Khazar, Khvalyn and Novo-Caspian (Fig. 3). Each stage included several transgressions and regressions. The Baku transgression occurred 400-500 thousand years ago, sea level rose to 5 abs. m. During the Khazar stage, there were two transgressions: early Khazar (250-300 thousand years ago, maximum level 10 abs. m) and late Khazar (100-200 thousand years ago, highest level -15 abs. m). The Khvalynian stage in the history of the Caspian Sea included two transgressions: the largest during the Pleistocene period, the Early Khvalynian (40-70 thousand years ago, maximum level 47 absolute meters, which is 74 m higher than the modern one) and the Late Khvalynian (10-20 thousand years ago, rise level up to 0 abs. m). These transgressions were separated by the deep Enotayev regression (22-17 thousand years ago), when sea level dropped to -64 abs. m and was 37 m lower than the modern one.



Rice. 4. Fluctuations in the level of the Caspian Sea over the past 10 thousand years. P is the natural range of fluctuations in the level of the Caspian Sea under climatic conditions characteristic of the sub-Atlantic Holocene epoch (risk zone). I-IV - stages of the New Caspian transgression; M - Mangyshlak, D - Derbent regression

Significant fluctuations in the level of the Caspian Sea also occurred during the New Caspian stage of its history, which coincided with the Holocene (the last 10 thousand years). After the Mangyshlak regression (10 thousand years ago, the level dropped to – 50 abs. m), five stages of the New Caspian transgression were noted, separated by small regressions (Fig. 4). Following fluctuations in sea level—its transgressions and regressions—the outline of the reservoir also changed (Fig. 5).

Over historical time (2000 years), the range of changes in the average level of the Caspian Sea was 7 m – from – 32 to – 25 abs. m (see Fig. 4). The minimum level in the last 2000 years was during the Derbent regression (VI-VII centuries AD), when it decreased to – 32 abs. m. During the time elapsed after the Derbent regression, the average sea level changed in an even narrower range - from – 30 to – 25 abs. m. This range of level changes is called the risk zone.

Thus, the level of the Caspian Sea has experienced fluctuations before, and in the past they were more significant than in the 20th century. Such periodic fluctuations are a normal manifestation of the unstable state of a closed reservoir with variable conditions at the outer boundaries. Therefore, there is nothing unusual in the decrease and increase in the level of the Caspian Sea.

Fluctuations in the level of the Caspian Sea in the past, apparently, did not lead to irreversible degradation of its biota. Of course, sharp drops in sea level created temporary unfavorable conditions, for example, for fish stocks. However, as the level rose, the situation corrected itself. Natural conditions coastal zone (vegetation, bottom animals, fish) experience periodic changes along with sea level fluctuations and, apparently, have a certain margin of stability and resistance to external influences. After all, the most valuable sturgeon stock has always been in the Caspian basin, regardless of sea level fluctuations, quickly overcoming temporary deterioration in living conditions.

Rumors that rising sea levels caused floods throughout the Volga delta were not confirmed. Moreover, it turned out that the increase in water levels even in the lower part of the delta is inadequate to the magnitude of the sea level rise. The increase in water level in the lower part of the delta during the low-water period did not exceed 0.2-0.3 m, and during the flood it almost did not appear at all. At the maximum level of the Caspian Sea in 1995, the backwater from the sea extended along the deepest branch of the delta, Bakhtemiru, no more than 90 km, and along other branches no more than 30 km. Therefore, only the islands on the seashore and the narrow coastal strip of the delta were flooded. Flooding in the upper and middle parts of the delta was associated with high floods in 1991 and 1995 (which is a normal phenomenon for the Volga delta) and with the unsatisfactory condition of protective dams. The reason for the weak influence of sea level rise on the regime of the Volga delta is the presence of a huge shallow coastal zone, which dampens the impact of the sea on the delta.

As for the negative impact of sea level rise on the economy and life of the population in the coastal zone, the following should be recalled. At the end of the last century, sea level was higher than it is now, and this was not perceived as ecological catastrophy. And before the level was even higher. Meanwhile, Astrakhan has been known since the middle of the 13th century, and here in the 13th - mid-16th centuries the capital of the Golden Horde, Sarai-Batu, was located. These and many others settlements on the Caspian coast did not suffer from high water levels, since they were located on elevated places and during abnormal flood levels or surges, people temporarily moved from low places to higher ones.

Why is it that now the consequences of sea level rise, even to lower levels, are perceived as a catastrophe? The reason for the enormous damage suffered by the national economy is not the rise in level, but the thoughtless and short-sighted development of a strip of land within the mentioned risk zone, freed (as it turned out, temporarily!) from under sea level after 1929, that is, when the level decreased below the mark - 26 abs. m. The buildings erected in the risk zone, naturally, turned out to be flooded and partially destroyed. Now, when a territory developed and polluted by humans is flooded, a dangerous ecological situation is actually created, the source of which is not natural processes, but unreasonable economic activity.

ABOUT THE REASONS FOR CASPIAN LEVEL FLUCTUATIONS

When considering the reasons for fluctuations in the level of the Caspian Sea, it is necessary to pay attention to the confrontation between two concepts in this area: geological and climatic. Significant contradictions in these approaches emerged, for example, at the international conference "Caspian-95".

According to the geological concept, the causes of changes in the level of the Caspian Sea include processes of two groups. The processes of the first group, according to geologists, lead to changes in the volume of the Caspian basin and, as a consequence, to changes in sea level. Such processes include vertical and horizontal tectonic movements of the earth's crust, accumulation of bottom sediments and seismic phenomena. The second group includes processes that, as geologists believe, affect the underground flow into the sea, either increasing or decreasing it. Such processes are called periodic extrusion or absorption of waters that saturate bottom sediments under the influence of changing tectonic stresses (changes in periods of compression and extension), as well as technogenic destabilization of the subsurface caused by oil and gas production or underground nuclear explosions. It is impossible to deny the fundamental possibility of the influence of geological processes on the morphology and morphometry of the Caspian basin and underground flow. However, at present, the quantitative connection of geological factors with fluctuations in the level of the Caspian Sea has not been proven.

There is no doubt that tectonic movements played a decisive role in the initial stages of the formation of the Caspian basin. However, if we take into account that the Caspian Sea basin is located within a geologically heterogeneous territory, which results in a periodic rather than linear nature of tectonic movements with repeated changes in sign, then one should hardly expect a noticeable change in the capacity of the basin. The tectonic hypothesis is not supported by the fact that the coastlines of the New Caspian transgressions on all sections of the Caspian coast (with the exception of certain areas within the Absheron archipelago) are at the same level.

There is no reason to believe that the cause of fluctuations in the level of the Caspian Sea is a change in the capacity of its depression due to the accumulation of sediments. The rate of filling of the basin with bottom sediments, among which the main role is played by river discharges, is estimated, according to modern data, to be about 1 mm/year or less, which is two orders of magnitude less than the currently observed changes in sea level. Seismic deformations, which are observed only near the epicenter and attenuate at close distances from it, cannot have any significant effect on the volume of the Caspian basin.

As for the periodic large-scale discharge of groundwater into the Caspian Sea, its mechanism is still unclear. At the same time, this hypothesis is contradicted, according to E.G. Maevu, firstly, the undisturbed stratification of silt waters, indicating the absence of noticeable migrations of water through the thickness of bottom sediments, and secondly, the absence of proven powerful hydrological, hydrochemical and sedimentation anomalies in the sea, which should have accompanied large-scale discharge of groundwater that could influence changes in reservoir level.

The main proof of the insignificant role of geological factors at present is the convincing quantitative confirmation of the plausibility of the second, climatic, or more precisely, water-balance concept of Caspian level fluctuations.

CHANGES IN THE COMPONENTS OF THE CASPIAN WATER BALANCE AS THE MAIN REASON FOR FLUCTUATIONS IN ITS LEVEL

For the first time, fluctuations in the level of the Caspian Sea were explained by changes climatic conditions(more specifically river flow, evaporation and precipitation on the sea surface) also E.Kh. Lentz (1836) and A.I. Voeikov (1884). Later, the leading role of changes in the components of the water balance in sea level fluctuations was proven again and again by hydrologists, oceanologists, physical geographers and geomorphologists.

The key to most of the studies mentioned is the development of a water balance equation and the analysis of its components. The meaning of this equation is as follows: the change in the volume of water in the sea is the difference between the incoming (river and underground runoff, precipitation on the sea surface) and outgoing (evaporation from the sea surface and outflow of water into the Kara-Bogaz-Gol Bay) components of the water balance. The change in the level of the Caspian Sea is the quotient of the change in the volume of its waters divided by the area of ​​the sea. The analysis showed that the leading role in the water balance of the sea belongs to the ratio of the runoff of the Volga, Ural, Terek, Sulak, Samur, Kura rivers and visible or effective evaporation, the difference between evaporation and precipitation on the sea surface. An analysis of the components of the water balance revealed that the largest contribution (up to 72% of the variance) to the level variability is made by the influx of river water, and more specifically, the runoff formation zone in the Volga basin. As for the reasons for the change in the Volga runoff itself, many researchers believe that they are associated with the variability of atmospheric precipitation (mainly winter) in the river basin. And the precipitation regime, in turn, is determined by atmospheric circulation. It has long been proven that the latitudinal type of atmospheric circulation contributes to an increase in precipitation in the Volga basin, and the meridional type contributes to a decrease.

V.N. Malinin revealed that the root cause of moisture entering the Volga basin should be sought in the North Atlantic, and specifically in the Norwegian Sea. It is there that an increase in evaporation from the sea surface leads to an increase in the amount of moisture transferred to the continent and, accordingly, to an increase in atmospheric precipitation in the Volga basin. The latest data on the water balance of the Caspian Sea, obtained by employees of the State Oceanographic Institute R.E. Nikonova and V.N. Bortnik, are given with clarifications by the author in table. 1. These data provide convincing evidence that the main causes of both the rapid drop in sea level in the 1930s and the sharp rise in 1978-1995 were changes in river flow, as well as visible evaporation.

Bearing in mind that river flow is one of the main factors influencing the water balance and, as a consequence, the level of the Caspian Sea (and the Volga flow provides at least 80% of the total river flow into the sea and about 70% of the incoming part of the Caspian water balance), It would be interesting to find a connection between sea level and the flow of the Volga alone, measured most accurately. Direct correlation of these quantities does not give satisfactory results.

However, the connection between sea level and Volga runoff is clearly visible if we take into account the river flow not for every year, but take the ordinates of the difference integral runoff curve, that is, the sequential sum of normalized deviations of annual runoff values ​​from the long-term average value (norm). Even a visual comparison of the course of the average annual levels of the Caspian Sea and the difference integral curve of the Volga runoff (see Fig. 2) allows us to identify their similarities.

Over the entire 98-year period of observations of the Volga runoff (Verkhnee Lebyazhye village at the top of the delta) and sea level (Makhachkala), the correlation coefficient of the connection between sea level and the ordinates of the difference integral runoff curve was 0.73. If we discard years with small changes in level (1900-1928), then the correlation coefficient increases to 0.85. If we take for analysis a period with a rapid decline (1929-1941) and a rise in level (1978-1995), then the overall correlation coefficient will be 0.987, and separately for both periods 0.990 and 0.979, respectively.

The above calculation results fully confirm the conclusion that during periods of a sharp decrease or rise in sea level, the levels themselves are closely related to the runoff (more precisely, to the sum of its annual deviations from the norm).

A special task is to assess the role of anthropogenic factors in fluctuations in the level of the Caspian Sea, and first of all, the reduction of river flow due to irreversible losses due to the filling of reservoirs, evaporation from the surface of artificial reservoirs, and water intake for irrigation. It is believed that since the 40s, irreversible water consumption has steadily increased, which has led to a reduction in the influx of river water to the Caspian Sea and an additional decrease in its level compared to the natural one. According to V.N. Malinin, by the end of the 80s, the difference between the actual sea level and the restored (natural) reached almost 1.5 m. At the same time, the total irrecoverable water consumption in the Caspian basin was estimated in those years at 36-45 km3/year (of which the Volga accounted for about 26 km3/year). If it were not for the withdrawal of river flow, sea level rise would have begun not in the late 70s, but in the late 50s.

The increase in water consumption in the Caspian basin by 2000 was predicted first to 65 km3/year, and then to 55 km3/year (36 of which were accounted for by the Volga). Such an increase in irrevocable losses of river flow should have reduced the level of the Caspian Sea by more than 0.5 m by 2000. In connection with assessing the impact of irreversible water consumption on the level of the Caspian Sea, we note the following. Firstly, estimates in the literature of the volumes of water intake and losses due to evaporation from the surface of reservoirs in the Volga basin are apparently significantly overestimated. Secondly, forecasts for the growth of water consumption turned out to be erroneous. The forecasts included the pace of development of water-consuming sectors of the economy (especially irrigation), which not only turned out to be unrealistic, but also gave way to a decline in production in recent years. In fact, as A.E. points out. Asarin (1997), by 1990, water consumption in the Caspian basin was about 40 km3/year, and has now decreased to 30-35 km3/year (in the Volga basin up to 24 km3/year). Therefore, the “anthropogenic” difference between the natural and actual sea level is currently not as great as predicted.

ABOUT POSSIBLE FLUCTUATIONS IN THE CASPIAN SEA LEVEL IN THE FUTURE

The author does not set himself the goal of analyzing in detail the numerous forecasts of fluctuations in the level of the Caspian Sea (this is an independent and difficult task). The main conclusion from assessing the results of forecasting Caspian level fluctuations can be drawn as follows. Although the forecasts were based on completely different approaches (both deterministic and probabilistic), there was not a single reliable forecast. The main difficulty in using deterministic forecasts based on the sea water balance equation is the lack of development of the theory and practice of ultra-long-term climate change forecasts over large areas.

When sea levels dropped in the 1930s to 1970s, most researchers predicted they would fall further. In the last two decades, when sea level rise began, most forecasts predicted an almost linear and even accelerating rise in sea level to -25 and even -20 abs. m and higher at the beginning of the 21st century. Three circumstances were not taken into account. Firstly, the periodic nature of fluctuations in the level of all closed reservoirs. The instability of the Caspian Sea level and its periodic nature is confirmed by an analysis of its current and past fluctuations. Secondly, at a sea level close to – 26 abs. m, the flooding of large bays-sors on the north-eastern coast of the Caspian Sea - Dead Kultuk and Kaydak, as well as low-lying areas in other places on the coast - will begin to flood, which have dried out at a low level. This would lead to an increase in the area of ​​shallow waters and, as a consequence, to an increase in evaporation (up to 10 km3/year). With more high level sea, the outflow of water into Kara-Bogaz-Gol will increase. All this should stabilize or at least slow down the level increase. Thirdly, level fluctuations under the conditions of the modern climatic era (the last 2000 years), as shown above, are limited by the risk zone (from – 30 to – 25 abs. m). Taking into account the anthropogenic decrease in runoff, the level is unlikely to exceed the level of 26-26.5 abs. m.

The decrease in average annual levels in the last four years by a total of 0.34 m may indicate that in 1995 the level reached its maximum (- 26.66 abs. m), and a change in the trend of the Caspian level. In any case, the prediction is that sea level is unlikely to exceed 26 absolute. m, apparently, is justified.

In the 20th century, the level of the Caspian Sea changed within 3.5 m, first falling and then rising sharply. This behavior of the Caspian Sea is the normal state of a closed reservoir as an open dynamic system with variable conditions at its inlet.

Each combination of incoming (river flow, precipitation on the sea surface) and outgoing (evaporation from the surface of a reservoir, outflow into the Kara-Bogaz-Gol Bay) components of the Caspian water balance corresponds to its own level of equilibrium. Since the components of the water balance of the sea also change under the influence of climatic conditions, the level of the reservoir fluctuates, trying to reach an equilibrium state, but never reaches it. Ultimately, the trend of changes in the Caspian Sea level in given time depends on the ratio of precipitation minus evaporation in the catchment area (in the basins of the rivers that feed it) and evaporation minus precipitation above the reservoir itself. There is actually nothing unusual about the recent rise in the Caspian sea level by 2.3 m. Such level changes have happened many times in the past and did not cause irreparable damage natural resources Caspian Sea. The current rise in sea level has become a disaster for the economy of the coastal zone only because of the unreasonable development by man of this risk zone.

Vadim Nikolaevich Mikhailov, Doctor of Geographical Sciences, Professor of the Department of Land Hydrology, Faculty of Geography, Moscow State University, Honored Scientist of the Russian Federation, Full Member of the Academy of Water Sciences. Area of ​​scientific interests – hydrology and water resources, interaction of rivers and seas, deltas and estuaries, hydroecology. Author and co-author of about 250 scientific works, including 11 monographs, two textbooks, four scientific and methodological manuals.

Caspian Sea short description endorheic salt lake of Eurasia and largest lake planets is described in this article. A message about the Caspian Sea will help you prepare for classes.

Caspian Sea: report

This water body is located at the geographical junction of Europe and Asia. The water level is 28 m below the level of the World Ocean. Over its long history, the Caspian Sea has “changed” more than 70 names. And it received its modern name from the ancient Caspian tribe, who were engaged in horse breeding and settled along the southwestern shore of the lake.

Salinity of the Caspian Sea not constant: near the mouth of the Volga River it is 0.05%, and in the southeast the figure increases to 13%. The area of ​​the water body today is about 371,000 km2, the maximum depth of the Caspian Sea is 1025 m.

Features of the Caspian Sea

Scientists have conditionally divided the lake-sea into 3 natural zones:

  • Northern
  • Average
  • Southern

Each of them has a different depth and composition of water. For example, the smallest part is Northern. The full-flowing Volga River flows here, so the salinity here is the lowest. And the southern part is the deepest, and, accordingly, salty.

The Caspian Sea was formed more than 10 million years ago. It can be called part of the ancient Tethys superocean, which once lay between the African, Indian and Eurasian continental plates. Its long history is also evidenced by the nature of the bottom and geological coastal deposits. The length of the coastline is 6500 - 6700 km, and including the islands up to 7000 km.

The shores of the Caspian Sea are predominantly smooth and low-lying. The northern part of the coastline is indented by islands and channels of the Ural and Volga deltas. The shore is swampy and low, covered with thickets. The eastern coast is characterized by limestone coasts that are adjacent to deserts and semi-deserts. The west and east coasts have winding coastlines.

Where does the Caspian Sea flow?

Since the Caspian Sea is an endorheic body of water, it is logical that it does not flow anywhere. But 130 rivers flow into it. The largest of them are Terek, Volga, Emba, Ural, Kura, Atrek, Samur.

Climate of the Caspian Sea

In the northern part of the sea the climate is continental, in the middle part it is temperate and in the southern part it is subtropical. in winter average temperature ranges from – 8 … – 10 ( Northern part) to +8 … + 10 ( South part). Summer average temperatures range from +24 (northern part) to +27 (southern part). The maximum temperature recorded on the east coast was 44 degrees.

Animal and plant life

The fauna is diverse and includes 1809 species. The sea is home to 415 invertebrates and 101 species of fish. It contains most of the world's reserves of pike perch, sturgeon, roach, and carp. The Caspian Sea is home to carp, mullet, bream, sprat, perch, kutum, pike, as well as such a large mammal as the Caspian seal.

The flora is represented by 728 species. The sea is dominated by diatoms, brown algae, red algae, blue-green algae, chara algae, ruppium and zoster.

The importance of the Caspian Sea

On its territory there are many gas and oil reserves, the fields of which are at the development stage. Scientists have calculated that oil resources amount to 10 billion tons, and gas condensate - 20 billion tons. The first oil well was drilled in 1820 on the Absheron shelf. Limestone, sand, salt, stone, and clay are also mined on its shelf.

In addition, the Caspian Sea is popular among tourists. Modern resort areas are being created on its banks, mineral water and dirt contribute to the development health complexes and sanatoriums. The most famous resorts- Amburan, Nardaran, Zagulba, Bilgah.

Environmental problems of the Caspian Sea

Sea waters are polluted as a result of the extraction and transportation of gas and oil on the shelf. Pollutants also come from the rivers that flow into it. Poaching of sturgeon caviar has led to a decrease in the number of these fish.

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