Caspian Sea. A small sea or a huge lake? (3 photos). Caspian lake. Why is the Caspian lake called the sea

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

Sochi, Anapa, Tuapse, Gelendzhik or Crimea? Or maybe the Baltic Sea is better? Or the Far East with excursions to killer whales, seals and whales? For many, all of the above is not something attractive and interesting, and some are completely frightened by prices, the level of service and the distance of the trip. In this case, many choose Thailand or Turkey - in general, to be inexpensive, warm and the sea is nearby. But for some reason everyone forgets about another sea in Russia...

Another sea

This sea is certainly no worse than the Black, and even more so the Baltic (no offense to fans of this coast). Yes, there is no lush flora and fauna, palaces and large embankments, but here you can find an inexpensive and pleasant vacation away from the hustle and bustle on long sandy beaches. It is probably very clear that we are talking about the Caspian Sea. Lack of infrastructure? Lake? Unsalted? Dangerous region? Wait, don't rush to throw stereotyped excuses - these are all myths that become popular due to the fact that few people really tried to find out anything about these places. For example, the water temperature in summer in the Caspian Sea is more than suitable for swimming and recreation with children. But first things first.

What is the Caspian Sea?

Alas, very few people really know at least something about this sea. Let's start with the fact that it is the largest drainless lake on our planet. Yes, it is called a lake for the reason that it does not have access to the ocean. And despite this, the Caspian has much more similarities with the sea than with a lake on the outskirts of an average Russian city.

In addition, the Caspian Sea is really huge: the distance from the northernmost point to the southern one is about 1200 kilometers. The width in some places reaches 500 kilometers. The Caspian Sea belongs to the deep seas: its maximum depth exceeds 1 kilometer.

According to the nature of the relief, it is conditionally divided into several parts: the Northern, Middle and Southern Caspian. The first part is the shallowest: the depth here does not exceed a couple of hundred meters. But the southern part occupies a large area - almost 66% of the entire sea. The countries that are located on the Caspian coast include Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan. Our country has about 650 km of coastline, the largest bay of this sea, which is called Kara-Bogaz-Gol, is also located here.

And now a surprise - the water in the Caspian Sea is salty! Not the same as in the Mediterranean Sea or the ocean, but not very different from the salinity of the Black, and even more so the Azov. According to the latest data, a salinity of 13 ppm was recorded in the southeast of the sea (against 17 off the coast of Sochi or Crimea). Yes, there are no dolphins here, and the underwater world is somewhat poorer, but in all other respects the Caspian is in no way inferior to any other sea.

Resorts of the Caspian Sea

Many tourists refuse to go to the coast of the Caspian Sea for only one reason - the temperature of the water. In fact, this is another stereotype. The coast of the Caspian Sea is famous for its comfortable climate. We will study the water temperature by months in detail, and now we will briefly go over the main resorts of these places.

Russia has two regions with access to and By the way, this fact also frightens many travelers who immediately recall news reports about another instability in Makhachkala. However, it should be noted that in the light of recent events, foreign resorts like Turkish ones, all the more so, cannot guarantee the safety of life and health. And in recent years, Dagestan has been increasingly included in the lists of the most visited places chosen by residents of the Russian Federation.

The most popular cities are Kaspiysk, Derbent and Makhachkala. By the way, the water temperature in the Caspian Sea in Makhachkala is no different from the water temperature in any other place on the Russian coast, since it is in the same climatic zone, like the entire basin of this amazing sea as a whole. There are numerous bases and hotels that offer a wide range of services. Fishermen will especially like it here, as they can rent all the necessary equipment for fishing or spearfishing. In addition, there are a lot of restaurants on the coast of the Caspian Sea where you can bring your catch and ask a professional chef to cook a delicious fish dinner.

As for housing, then, as mentioned above, here you can find a room or a house for every taste and budget. In addition to ordinary buildings, everyone will be able to rent floating houses right on the water. In a word, there really is plenty to choose from, and the issue of housing and entertainment in the resorts of the Caspian Sea can be a topic for a separate article.

Beaches and weather

The Caspian coast is very attractive for families: there are no pebble beaches with sharp or large stones that are painful and unpleasant to walk on. The entrance to the sea is also very pleasant, the depth is gradually gaining, and there is a soft sandy surface under your feet. At the same time, the sand here does not have a dirty gray tint. The period from June to October is the most pleasant time of the year to relax on the Caspian Sea. The water temperature in summer is much higher here than at any other time of the year, and in the southern part the sea warms up faster than in the north. The air also warms up to a comfortable temperature in the summer, but here it never gets hot and too humid, as in the resorts of the Krasnodar Territory. If in Sochi the thermometers show up to 40 degrees Celsius, here the thermometers do not go over 30.

Water temperature

Finally, consider the water temperature in the Caspian Sea. At the very beginning, it should be noted that today it is possible to monitor data on the Web. On specialized weather sites, you can see what the water temperature is in the Caspian Sea, for example, in Kaspiysk or any other city.

Local residents and tourists open the swimming season at the end of May, when the water warms up to +18 degrees. The same temperature happens in October, which makes it possible to relax here as much as on the Black Sea coast. The warmest sea becomes around July-August. At this time, the water reaches 27-28 degrees Celsius.

conclusions

Thus, the Caspian Sea remains a very attractive place for recreation and for the development of resort infrastructure. Despite the fact that there are very pleasant and comfortable weather conditions here, the tourist flow to the Russian coast of the Caspian Sea is several times lower than to the resorts of the Crimea or Kuban, which ensures a quiet and relaxing holiday on uncrowded sandy beaches. At the same time, the water temperature in the Caspian Sea ranges from 18 degrees in May and October to 27 degrees in July and August.

The Caspian Sea is the largest drainless lake on the planet. This body of water is called the sea for its huge size, brackish water and sea-like regime. The level of the Caspian Sea-lake lies much lower than the level of the World Ocean. At the beginning of 2000, he had a mark of about - 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 is elongated from south to north (Fig. 1). The Caspian washes the shores of Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran. The reservoir is rich in fish, its bottom and banks are rich in oil and gas. The Caspian Sea is quite well studied, but many mysteries remain in its regime. The most characteristic feature of the reservoir is the instability of the level with sharp drops and rises. The last rise in the level of the Caspian took place before our eyes from 1978 to 1995. It gave rise to many rumors and speculation. Numerous publications appeared in the press, which spoke about catastrophic floods and ecological catastrophe. It was often written 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 such behavior of the Caspian Sea?

WHAT HAPPENED TO THE CASPIAN IN THE 20TH CENTURY

Systematic observations over the level of the Caspian Sea were started in 1837. In the second half of the 19th century, the average annual values ​​of the Caspian Sea level were in the range of marks from -26 to -25.5 abs. m and showed a slight downward trend. This trend continued into the 20th century (Fig. 2). In the period from 1929 to 1941, the 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 mark for 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 a mark of 26.66 abs. m. In the next four years, the average sea level decreased by almost 30 cm. Its average marks 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 the years 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 level drop. There were many more negative consequences. With a decrease in the level, the areas of forage land for fish stocks in the northern Caspian have decreased. The shallow estuarine coast of the Volga began to quickly overgrow with aquatic vegetation, which worsened the conditions for the passage of fish to spawn in the Volga. Catches of fish, especially valuable species such as sturgeon and sterlet, have sharply decreased. Shipping began to suffer damage due to the fact that the depths in the approach channels decreased, especially near the Volga delta.

The rise in the level 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 a low level.

Many sectors of the economy began to suffer damage. Significant territories turned out to be in the zone of flooding and flooding, especially in the northern (flat) part of Dagestan, in Kalmykia and the Astrakhan region. The cities of Derbent, Kaspiysk, Makhachkala, Sulak, Caspian (Lagan) and dozens of other smaller settlements suffered from the level rise. Significant areas of agricultural land have been flooded and flooded. Roads and power lines, engineering structures of industrial enterprises and public utilities are being destroyed. A threatening situation has developed with fish-breeding enterprises. Abrasion processes in the coastal zone and the effect of sea water surges have intensified. In recent years, the flora and fauna of the seashore and the coastal zone of the Volga delta suffered significant damage.

In connection with the increase in depth in the shallow waters of the Northern Caspian and the reduction in the areas occupied in these places by aquatic vegetation, 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 the rising sea level made us speak of an ecological catastrophe. The development of measures to protect national economic objects and settlements from the advancing sea began.

HOW UNUSUAL IS CURRENT CASPIAN BEHAVIOR?

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 are archaeological, cartographic and other evidence for historical time and the results of paleogeographic studies covering a longer period.

It is proved 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. In this period of time in the history of the Caspian, four stages are distinguished: Baku, Khazar, Khvalyn and New Caspian (Fig. 3). Each stage included several transgressions and regressions. The Baku transgression occurred 400-500 thousand years ago, the sea level rose to 5 abs. m. During the Khazar stage, there were two transgressions: the early Khazar (250-300 thousand years ago, the maximum level is 10 abs. m) and the late Khazar (100-200 thousand years ago, the highest level is 15 abs. m). The Khvalyn stage in the history of the Caspian included two transgressions: the largest for the Pleistocene period, the early Khvalyn (40-70 thousand years ago, the maximum level is 47 abs. m, which is 74 m higher than the modern one) and the late Khvalyn (10-20 thousand years ago, the rise level up to 0 abs. m). These transgressions were separated by a deep Enotaevskaya regression (22-17 thousand years ago), when the 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 subatlantic epoch of the Holocene (risk zone). I-IV - stages of the New Caspian transgression; M - Mangyshlak, D - Derbent regression

Significant fluctuations in the level of the Caspian 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, a level decrease to -50 abs. m), five stages of the New Caspian transgression were noted, separated by small regressions (Fig. 4). Following sea level fluctuations, its transgressions and regressions, the outline of the reservoir also changed (Fig. 5).

Over the 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 that has passed since the Derbent regression, the average sea level has 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 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 lowering and rising of the level of the Caspian Sea.

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

Rumors that rising sea levels have caused flooding throughout the Volga Delta have not been 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 the water level in the lower part of the delta during the low water period did not exceed 0.2-0.3 m, and almost did not manifest itself during the flood. At the maximum level of the Caspian Sea in 1995, the backwater from the sea extended along the deepest branch of the Bakhtemir delta by no more than 90 km, and along other branches by no more than 30 km. Therefore, only islands on the seashore and a 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 normal for the Volga delta) and with the unsatisfactory condition of protective dams. The reason for the weak effect of sea level rise on the regime of the Volga delta is the presence of a huge shallow coastal zone, which dampens the effect of the sea on the delta.

With regard to 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, the sea level was higher than at present, and this was not perceived as an ecological disaster. And before the level was even higher. Meanwhile, Astrakhan has been known since the middle of the 13th century, and Sarai-Batu, the capital of the Golden Horde, was located here in the 13th - mid-16th centuries. These and many other settlements on the Caspian coast did not suffer from high level standing, since they were located on elevated places and during abnormal flood levels or surges, people temporarily moved from low places to higher ones.

Why, then, are the consequences of a rise in sea level even to smaller levels now perceived as a catastrophe? The reason for the enormous damage that the national economy suffers is not the rise in the 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 the sea level after 1929, that is, with a decrease in the level below the mark - 26 abs. m. The buildings erected in the risk zone, of course, turned out to be flooded and partially destroyed. Now, when the territory developed and polluted by man is flooded, a dangerous ecological situation is really created, the source of which is not natural processes, but unreasonable economic activity.

ABOUT THE REASONS FOR THE CASPIAN LEVEL FLUCTUATIONS

Considering the issue of the causes of fluctuations in the level of the Caspian Sea, it is necessary to pay attention to the confrontation in this area of ​​two concepts: geological and climatic. Significant contradictions in these approaches were revealed, for example, at the international conference "Caspian-95".

According to the geological concept, two groups of processes are attributed to the causes of changes in the level of the Caspian Sea. The processes of the first group, according to geologists, lead to a change in the volume of the Caspian depression and, as a result, to changes in sea level. Such processes include vertical and horizontal tectonic movements of the earth's crust, accumulation of bottom sediments, and seismic events. The second group includes processes that, as geologists believe, affect the underground runoff into the sea, either increasing it or decreasing it. Such processes are called periodic extrusion or absorption of water, which saturate bottom sediments under the influence of changing tectonic stresses (changes in periods of compression and tension), as well as technogenic destabilization of the subsoil due to 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 depression and underground runoff. However, at present, the quantitative relationship 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 depression. 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 sign changes, then one should hardly expect a noticeable change in the capacity of the basin. Not in favor of the tectonic hypothesis is the fact that the coastlines of the New Caspian transgressions in all sections of the Caspian coast (with the exception of certain areas within the Apsheron archipelago) are at the same level.

There are no grounds to consider the change in the capacity of its basin due to the accumulation of precipitation as the reason for fluctuations in the level of the Caspian Sea. The rate of filling the basin with bottom sediments, among which the main role is played by river discharges, is estimated, according to modern data, at a value of 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 noted 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. Maev, firstly, the undisturbed stratification of interstitial waters, indicating the absence of noticeable migrations of waters 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 a large-scale discharge of groundwater capable of affect changes in water levels.

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

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

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

The key to most of the studies mentioned is the compilation of the 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, atmospheric 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 is the quotient of dividing the change in the volume of its waters 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 flow of the Volga, Ural, Terek, Sulak, Samur, Kura rivers and visible or effective evaporation, the difference between evaporation and atmospheric precipitation on the sea surface. An analysis of the components of the water balance revealed that the largest contribution (up to 72% of the dispersion) to the level variability comes from the inflow of river waters, and more specifically, the runoff formation zone in the Volga basin. As for the reasons for the change in the flow of the Volga itself, they are associated, as many researchers believe, with the variability of atmospheric precipitation (mainly winter) in the river basin. And the mode of precipitation, in turn, is determined by the circulation of the atmosphere. It has long been proven that the latitudinal type of atmospheric circulation contributes to an increase in precipitation in the Volga basin, while 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 the 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, received by the staff of the State Oceanographic Institute R.E. Nikonova and V.N. Bortnik, are given with the author's clarifications in Table. 1. These data convincingly prove that the main reasons for 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 apparent evaporation.

Keeping in mind that river runoff is one of the main factors affecting the water balance and, as a result, the level of the Caspian Sea (and the Volga runoff provides at least 80% of the total river runoff to 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 one Volga, measured most accurately. Direct correlation of these quantities does not give satisfactory results.

However, the relationship between the sea level and the Volga runoff is well traced if the river runoff is not taken into account for each year, but the ordinates of the difference integral runoff curve are taken, that is, the sequential sum of the normalized deviations of the 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) makes it possible to reveal their similarity.

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

The presented 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 above all, the reduction in river flow due to its irretrievable losses for filling reservoirs, evaporation from the surface of artificial reservoirs, and water withdrawal for irrigation. It is believed that since the 1940s, irretrievable water consumption has been steadily increasing, which has led to a reduction in the inflow of river waters 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 1980s, the difference between the actual sea level and the restored (natural) level reached almost 1.5 m. about 26 km3/year). If it were not for the withdrawal of river runoff, then the rise in sea level would have begun not at the end of the 70s, but at the end of the 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 them were in the Volga). Such an increase in irretrievable losses of river runoff should have lowered the level of the Caspian by more than 0.5 m by 2000. In connection with the assessment of the impact of irreversible water consumption on the level of the Caspian, we note the following. First, estimates of water withdrawal volumes and evaporation losses from the surface of reservoirs in the Volga basin found in the literature seem to be significantly overestimated. Secondly, forecasts of water consumption growth turned out to be erroneous. The forecasts included the rate 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. 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 to 24 km3/year). Therefore, the "anthropogenic" difference between the natural and actual sea levels is currently not as large as predicted.

ON POSSIBLE FLUCTUATIONS OF THE CASPIAN 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 the assessment of the results of forecasting fluctuations in the level of the Caspian 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 forecasts of climate change over large areas.

When the sea level decreased in the 30-70s, most researchers predicted its further fall. In the last two decades, when sea level rise began, most forecasts predicted an almost linear and even accelerating rise in level to -25 and even -20 abs. m and above at the beginning of the XXI century. In this case, three factors were not taken into account. First, the periodic nature of fluctuations in the level of all endorheic reservoirs. The instability of the Caspian level and its periodic nature are confirmed by the analysis of its current and past fluctuations. Secondly, at sea level close to - 26 abs. m, the flooding of large sor bays on the northeastern coast of the Caspian Sea - Dead Kultuk and Kaydak, as well as low-lying areas in other places of the coast, dried up at a low standing level, will begin. This would lead to an increase in the area of ​​shallow waters and, as a consequence, an increase in evaporation (up to 10 km3/year). With a higher sea level, the outflow of water to Kara-Bogaz-Gol will increase. All this should stabilize or at least slow down the level growth. Thirdly, level fluctuations under the conditions of the modern climatic epoch (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 mark of 26-26.5 abs. m.

The decrease in average annual levels in the last four years by a total of 0.34 m, possibly indicates 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 that sea level is unlikely to exceed 26 abs. m, apparently justified.

In the 20th century, the level of the Caspian Sea changed within 3.5 m, first dropping and then rising sharply. Such 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 runoff, precipitation on the sea surface) and outgoing (evaporation from the surface of the reservoir, outflow to 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 in the level of the Caspian Sea at a 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 over the reservoir itself. There is really nothing unusual about the recent rise of the Caspian Sea level by 2.3 m. Such level changes have occurred many times in the past and did not cause irreparable damage to the natural resources of the Caspian. The current rise in sea level has become a catastrophe for the economy of the coastal zone only because of the unreasonable development of this risk zone by man.

Vadim Nikolaevich Mikhailov, Doctor of Geographical Sciences, Professor of the Department of Terrestrial Hydrology of the Faculty of Geography of Moscow State University, Honored Worker of Science of the Russian Federation, full member of the Academy of Water Management 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 papers, including 11 monographs, two textbooks, four scientific and methodological manuals.

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

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

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

Map of the Caspian Sea

The Caspian Sea washes the shores of five coastal states:

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

Water temperature

is subject to significant latitudinal changes, most pronounced in winter, when the temperature varies from 0 - 0.5 °C at the ice edge in the north of the sea to 10 - 11 °C in the south, that is, the water temperature difference is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average, the water temperature near the western coast is 1 - 2 °C higher than that of the eastern coast, and in the open sea the water temperature is 2 - 4 °C higher than near the coasts.

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

Animal world

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

Vegetable world

Vegetable world Caspian Sea and its coast is represented by 728 species. From plants to Caspian Sea algae predominate - blue-green, diatoms, red, brown, char and others, from flowering ones - zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought into Caspian Sea by a person consciously or on the bottoms of ships.

Mining of oil and gas

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

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

In addition to oil and gas production, on the coast Caspian Sea and the Caspian shelf, salt, limestone, stone, sand, and clay are also being mined.

Ecological problems

Ecological problems Caspian Sea 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 Caspian Sea, the vital activity of coastal cities, as well as the flooding of individual facilities due to an increase in the level Caspian Sea. Predatory harvesting of sturgeons and their caviar, rampant poaching lead to a decrease in the number of sturgeons and forced restrictions on their production and export.

The Caspian Sea is the largest lake on our planet. It is located between Europe and Asia and is called the sea for its size.

Caspian Sea

The water level is below the level of 28m. The water in the Caspian Sea has less salinity in the north in the delta. The highest salinity is observed in the southern regions.

The Caspian Sea covers an area of ​​371 thousand km2, the greatest depth is 1025 meters (South Caspian depression). The coastline is estimated from 6500 to 6700 km, and if you take it together with the islands, then more than 7000 km.

The seashore is mostly low-lying and smooth. If you look at the northern part, then there are many islands, water channels, indented by the Volga and the Urals. In these places, the coast is swampy and covered with thickets. From the east, semi-desert and desert terrain with limestone shores approaches the sea. The area of ​​the Kazakh Bay, the Absheron Peninsula and the Kara-Bogaz-Gol Bay have winding shores.

Bottom relief

The bottom relief is divided into three main forms. Shelf in the northern part, the average depth here is from 4 to 9 m, the maximum depth is 24 m, which gradually increases and reaches 100 m. The continental slope in the middle part drops to 500 m. The Mangyshlak threshold separates the northern part from the middle part. Here one of the deepest places is the Derbent depression (788 m).

2. Heraz, Babol, Sefudrud, Gorgan, Polerud, Chalus, Tejen - https://site/russia/travel/po-dagestanu.html;

4. Atrek - Turkmenistan;

Samur is located on the border between Azerbaijan and Russia, Astarachay is on the border of Azerbaijan and Iran.

The Caspian Sea belongs to five states. From the west and northwest, the length of the coast of 695 km is the territory of Russia. Most of the coastline with a length of 2320 km belongs to Kazakhstan in the east and northeast. Turkmenistan has 1,200 km in the southeast, Iran has 724 km in the south, and Azerbaijan has 955 km of coastline in the southwest.

In addition to the five states that have access to the sea, the Caspian basin also includes Armenia, Turkey, and Georgia. The Volga (Volga-Baltic Way, White Sea-Baltic Canal) connects the sea with the World Ocean. There is a connection with the Azov and Black Seas through the Volga-Don Canal, with the Moscow River (the Moscow Canal).

The main ports are Baku in Azerbaijan; Makhachkala in ; Aktau in Kazakhstan; Olya in Russia; Nowshahr, Bander-Torkemen and Anzeli in Iran.

The largest bays of the Caspian Sea: Agrakhan, Kizlyar, Kaydak, Kazakh, Dead Kultuk, Mangyshlak, Hasan-kuli, Turkmenbashi, Kazakh, Gyzlar, Enzeli, Astrakhan, Gyzlar.

Until 1980, Kara-Bogaz-Gol was a bay-lagoon, which was connected to the sea by a narrow strait. Now it is a salt lake, separated from the sea by a dam. After the construction of the dam, the water began to decrease sharply, and a culvert had to be built. Through it, up to 25 km3 of water enters the lake annually.

Water temperature

The greatest fluctuations in temperature are observed in winter. In shallow water, it reaches 100 in winter. The difference between summer and winter temperatures reaches 240. On the coast in winter, it is always 2 degrees lower than in the open sea. The optimum warming up of the water occurs in July-August, in shallow water the temperature reaches 320. But at this time, north-western winds raise cold layers of water (upwelling). This process begins already in June and reaches intensity in August. The temperature at the surface of the water drops. The temperature difference between the layers disappears by November.

The climate in the northern part of the sea is continental, in the middle part it is temperate, and in the southern part it is subtropical. On the east coast, the temperature is always higher than on the west. Once on the east coast recorded 44 degrees.

The composition of the Caspian waters

About salinity is 0.3%. This is a typical desalinated pool. But the farther south, the higher the salinity. In the southern part of the sea, it already reaches 13%, and in Kara-Bogaz-Gol more than 300%.

Storms are frequent in shallow water areas. They occur due to changes in atmospheric pressure. Waves can reach 4 meters.

The water balance of the sea depends on river flows and precipitation. Among them, the Volga makes up almost 80% of all other rivers.

In recent years, there has been a rapid pollution of water by oil products and phenols. Their level already exceeds the permissible level.

Minerals

Back in the 19th century, the beginning of hydrocarbon production was laid. These are the main natural resources. There are also mineral, balneological biological resources here. Today, in addition to gas and oil production, sea-type salts (Astrakhanite, mirabalite, halite), sand, limestone, and clay are mined on the shelf.

Animal and plant world

The fauna of the Caspian Sea is up to 1800 species. Of these, 415 are vertebrates, 101 species of fish, and there is a world stock of sturgeons. Freshwater fish such as carp, pike perch, and vobla also live here. They catch carp, salmon, pike, bream in the sea. The Caspian Sea is the habitat of one of the mammals - the seal.

From plants, blue-green algae, brown, red can be noted. Zostera and ruppia also grow, they are classified as flowering algae.

The plankton brought into the sea by birds begins to bloom in spring, the sea is literally covered with greenery, and rhizosolation during flowering paints most of the sea territory in yellow-green color. The accumulation of rhizosolenia is so dense that even waves can calm down. In some places near the coast, literally meadows of algae have grown.

On the coast you can see both local and migratory birds. In the south, geese, ducks winter, birds such as pelicans, herons, flamingos arrange nesting.

The Caspian Sea contains almost 90% of the world's sturgeon stocks. But recently, the environment has been deteriorating, you can often meet poachers who hunt sturgeon because of expensive caviar.

Governments are investing a lot of money to improve the situation. They purify sewage, build factories for breeding fish, despite these measures, it is necessary to limit the production of sturgeon.