The Caspian Sea is artificial or not. Resources of the Caspian Sea

The Caspian Sea is inland and is located in an extensive continental depression on the border of Europe and Asia. The Caspian Sea has no connection with the ocean, which formally allows us to call it a lake, but it has all the features of the sea, since in past geological eras it had connections with the ocean.

The sea area is 386.4 thousand km2, the volume of water is 78 thousand m3.

The Caspian Sea has a vast drainage basin, with an area of ​​about 3.5 million km2. The nature of the landscapes, climatic conditions and types of rivers are different. Despite its vastness, only 62.6% of its area falls on waste areas; about 26.1% - for closed drainage. The area of ​​the Caspian Sea itself is 11.3%. 130 rivers flow into it, but almost all of them are located in the north and west (and the eastern bank does not have a single river reaching the sea at all). The largest river in the Caspian basin is the Volga, which provides 78% of the river waters entering the sea (it should be noted that more than 25% of Russia's economy is located in the basin of this river, and this undoubtedly determines many and other features of the Caspian Sea waters), as well as the Kura River , Zhaiyk (Ural), Terek, Sulak, Samur.

Physically and geographically and by nature, the sea is divided into three parts: northern, middle and southern. The conditional border between the northern and middle parts runs along the line of the Chechen island - Cape Tyub-Karagan, between the middle and southern - along the line of the island Zhiloy - Cape Kuuli.

The shelf of the Caspian Sea is, on average, limited to a depth of about 100 m. The continental slope, which begins below the edge of the shelf, ends in the middle part at a depth of 500–600 m, in the southern part, where it is very steep, at 700–750 m.

The northern part of the sea is shallow, its average depth is 5–6 m, maximum depths of 15–20 m are located on the border with the middle part of the sea. The bottom relief is complicated by the presence of banks, islands, grooves.

The middle part of the sea is a separate basin, the area of ​​the maximum depths of which - Derbent - is shifted to the western coast. The average depth of this part of the sea is 190 m, the greatest is 788 m.

The southern part of the sea is separated from the middle Absheron threshold, which is a continuation. The depths above this underwater ridge do not exceed 180 m. The deepest part of the South Caspian depression with a maximum depth of 1025 m for the sea is located east of the Kura delta. Several underwater ridges up to 500 m high rise above the bottom of the basin.

The shores of the Caspian Sea are diverse. In the northern part of the sea, they are rather strongly indented. Here are the Kizlyarsky, Agrakhansky, Mangyshlaksky bays and many shallow bays. Notable peninsulas: Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak. Large islands in the northern part of the sea - Tyuleniy, Kulaly. In the deltas of the Volga and Ural rivers, the coastline is complicated by many islets and channels, which often change their position. Many small islands and banks are located in other areas. coastline.

The middle part of the sea has a relatively flat coastline. On the west coast bordering southern part the sea is the Absheron Peninsula. To the east of it are the islands and banks of the Absheron archipelago, of which the most large island Residential. The eastern coast of the Middle Caspian is more indented, here the Kazakh Gulf with Kenderli Bay and several capes stand out. The largest bay on this coast is.

Farther south Absheron Peninsula the islands of the Baku archipelago are located. The origin of these islands, as well as some banks off the eastern coast of the southern part of the sea, is associated with the activity of underwater mud volcanoes lying on the bottom of the sea. On east coast there are large bays of Turkmenbashy and Turkmensky, and near the island of Ogurchinsky.

One of the most striking phenomena of the Caspian is the periodic variability of its level. In historical time, the Caspian Sea had a level lower than the World Ocean. Fluctuations in the level of the Caspian Sea are so great that for more than a century they have attracted the attention of not only scientists. Its peculiarity is that in the memory of mankind its level has always been below the level of the World Ocean. Since the beginning of instrumental observations (since 1830) over the sea level, the amplitude of its fluctuations was almost 4 m, from –25.3 m in the eighties of the XIX century. to –29 m in 1977. In the last century, the level of the Caspian Sea changed significantly twice. In 1929, it stood at about –26 m, and since it was close to this mark for almost a century, this level position was considered as a mean annual or secular level. In 1930, the level began to decline rapidly. By 1941, it dropped by almost 2 m. This led to the drying up of vast coastal bottom areas. A decrease in the level, with its small fluctuations (short-term insignificant level rises in 1946-1948 and 1956-1958), continued until 1977 and reached -29.02 m, that is, the level took the lowest position in the last 200 years.

In 1978, contrary to all forecasts, the sea level began to rise. As of 1994, the level of the Caspian Sea was at –26.5 m, that is, in 16 years the level rose by more than 2 m. The rate of this rise is 15 cm per year. The increase in the level in some years was higher, and in 1991 it reached 39 cm.

The general fluctuations in the level of the Caspian Sea are superimposed on its seasonal changes, the average long-term of which reaches 40 cm, as well as surges. The latter are especially pronounced in the Northern Caspian. For north west coast characterized by large surges created by the prevailing storms of the eastern and southeastern directions, especially during the cold period of the year. A number of large (more than 1.5–3 m) surges have been observed here over the past decades. An especially large surge with catastrophic consequences was noted in 1952. Fluctuations in the level of the Caspian Sea cause great damage to the states surrounding its water area.

Climate... The Caspian Sea is located in the temperate and subtropical. Climatic conditions change in the meridional direction, since the sea stretches for almost 1200 km from north to south.

In the Caspian region, various circulation systems interact, however, during the year, the winds of the eastern points prevail (the influence of the Asian maximum). The position in rather low latitudes provides a positive balance of heat inflow, therefore the Caspian Sea serves as a source of heat and moisture for most of the year for those passing by. The average annual in the northern part of the sea is 8–10 ° С, in the middle - 11–14 ° С, in the southern part - 15–17 ° С. However, in the northernmost regions of the sea, the average January temperature is from –7 to –10 ° С, and the minimum during invasions is up to –30 ° С, which determines the formation of the ice cover. In summer, the entire region under consideration is dominated by rather high temperatures - 24–26 ° С. Thus, the North Caspian is subject to the sharpest temperature fluctuations.

The Caspian Sea is characterized by a very small amount of precipitation falling per year - only 180 mm, and most of it falls on the cold season of the year (from October to March). However, the North Caspian Sea differs in this respect from the rest of the basin: here the average annual precipitation is less (for the western part, only 137 mm), and the seasonal distribution is more even (10–18 mm per month). In general, we can talk about proximity to arid.

Water temperature. Distinctive features The Caspian Sea (large differences in depths in different parts of the sea, nature, isolation) have a certain impact on the formation of temperature conditions. In the shallow North Caspian, the entire water column can be regarded as homogeneous (the same applies to shallow bays located in other parts of the sea). In the Middle and South Caspian, surface and deep masses can be distinguished, separated by a transitional layer. In the North Caspian and in the surface layers of the Middle and South Caspian, the water temperature varies over a wide range. In winter, temperatures change from north to south from less than 2 to 10 ° С, the water temperature near the western coast is 1–2 ° С higher than that of the east, in the open sea the temperature is higher than at the coasts: by 2–3 ° С in the middle part and by 3–4 ° С in the southern part of the sea. In winter, the temperature distribution is more uniform with depth, which is facilitated by the winter vertical circulation. In moderate and severe winters in the northern part of the sea and shallow bays on the eastern coast, the water temperature drops to freezing point.

In summer, the temperature changes in space from 20 to 28 ° C. The highest temperatures are observed in the southern part of the sea, and temperatures are also quite high in the well-warmed shallow North Caspian. The zone of distribution of the lowest temperatures is adjacent to the eastern coast. This is due to the rise of cold deep waters to the surface. Temperatures are also relatively low in the poorly warmed deep-water central part. In the open areas of the sea, in late May – early June, a layer of temperature jump begins, which is most pronounced in August. Most often it is located between 20 and 30 m in the middle part of the sea and 30 and 40 m in the south. In the middle part of the sea, due to the drive off the east coast, the shock layer rises close to the surface. In the bottom layers of the sea, the temperature throughout the year is about 4.5 ° C in the middle and 5.8–5.9 ° C in the southern part.

Salinity... The salinity values ​​are determined by such factors as river runoff, water dynamics, including mainly wind and gradient currents, the resulting water exchange between the western and eastern parts The North Caspian and between the North and Middle Caspian, the bottom topography, which determines the location of waters with different, mainly along isobaths, evaporation, providing a shortage of fresh water and the inflow of more saline ones. These factors collectively affect seasonal differences in salinity.

The North Caspian can be seen as a constant mixing of river and Caspian waters. The most active mixing occurs in the western part, where both river and Middle Caspian waters directly flow. In this case, the horizontal salinity gradients can reach 1 ‰ per 1 km.

The eastern part of the North Caspian is characterized by a more uniform salinity field, since most of the river and sea (Middle Caspian) waters enter this sea area in a transformed form.

According to the values ​​of the horizontal salinity gradients, it is possible to distinguish in the western part of the North Caspian a river-sea contact zone with water salinity from 2 to 10 ‰, in the eastern part from 2 to 6 ‰.

Significant vertical gradients of salinity in the North Caspian are formed as a result of the interaction of river and sea ​​waters, the decisive role in this is played by the runoff. The intensification of vertical stratification is also facilitated by the unequal thermal state of the water layers, since the temperature of the surface desalinated water arriving in summer from the seaside is 10–15 ° C higher than that of the near-bottom.

In the deep-water basins of the Middle and South Caspian, salinity fluctuations in the upper layer are 1–1.5 ‰. The greatest difference between the maximum and minimum salinity was noted in the area of ​​the Absheron sill, where it is 1.6 ‰ in the surface layer and 2.1 ‰ at the 5 m horizon.

The decrease in salinity along the western coast of the South Caspian in the 0–20 m layer is caused by the Kura river runoff. The influence of the Kura runoff decreases with depth; at the depths of 40–70 m, the range of salinity fluctuations is no more than 1.1 ‰. Along the entire western coast to the Absheron Peninsula, there is a strip of desalinated waters with a salinity of 10–12.5 ‰ coming from the North Caspian.

In addition, in the South Caspian, an increase in salinity occurs when saline waters are carried out from bays and bays on the eastern shelf under the influence of southeastern winds. Subsequently, these waters are transferred to the Middle Caspian.

In the deep layers of the Middle and South Caspian, salinity is about 13 ‰. In the central part of the Middle Caspian, such salinity is observed at horizons below 100 m, and in the deep-water part of the South Caspian, the upper boundary of waters with increased salinity drops to 250 m. It is obvious that in these parts of the sea, vertical mixing of waters is difficult.

Surface water circulation... The currents in the sea are mainly wind-driven. In the western part of the Northern Caspian, the currents of the western and eastern quarters are most often observed, in the eastern - southwestern and southern. The currents caused by the runoff of the Volga and Ural rivers are traced only within the estuarine seashore. The prevailing current velocities are 10–15 cm / s, in the open regions of the Northern Caspian the maximum velocities are about 30 cm / s.

In the coastal areas of the middle and southern parts of the sea, in accordance with the directions of the wind, currents of the north-west, north, south-east and south directions are observed, along the east coast currents of the east direction often take place. Along the western coast of the middle part of the sea, the most stable currents are southeastern and southern. The velocities of the currents are on average about 20–40 cm / s, the maximum ones reach 50–80 cm / s. Other types of currents also play a significant role in the circulation of sea waters: gradient, seiche, inertial.

Ice formation... The North Caspian is covered with ice annually in November, the area of ​​the freezing part of the water area depends on the severity of winter: in severe winters, the entire North Caspian is covered with ice, in soft ice it is kept within the 2-3 meter isobath. The appearance of ice in the middle and southern parts of the sea occurs in December-January. On the east coast, ice is of local origin, on the west coast - most often brought from the northern part of the sea. In severe winters near the eastern coast of the middle part of the sea, shallow bays freeze, near the coast, coastlines and fast ice form, near the western coast, drifting ice in abnormally cold winters extends to the Absheron Peninsula. The disappearance of the ice cover is observed in the second half of February – March.

Oxygen content... The spatial distribution of dissolved oxygen in the Caspian Sea has a number of regularities.
The central part of the Northern Caspian is characterized by a fairly uniform oxygen distribution. An increased oxygen content is found in the areas of the pre-estuarine seashore of the Volga River, a lower one - in the southwestern part of the North Caspian.

In the Middle and South Caspian, the highest oxygen concentrations are confined to coastal shallow areas and pre-estuarine coastal areas of rivers, with the exception of the most polluted areas of the sea (Baku Bay, Sumgait region, etc.).

In the deep-water areas of the Caspian Sea, the main regularity remains in all seasons - a decrease in oxygen concentration with depth.
Due to the autumn-winter cooling, the density of the waters of the North Caspian increases to a value at which it becomes possible for the North Caspian waters with a high oxygen content to flow along the continental slope to significant depths of the Caspian Sea.

The seasonal distribution of oxygen is mainly associated with the annual course and the seasonal ratio of production and destruction processes taking place in the sea.

In spring, the production of oxygen in the process of photosynthesis very significantly overlaps the decrease in oxygen caused by a decrease in its solubility with an increase in water temperature in spring.

In the areas of estuarine seaside rivers feeding the Caspian Sea, in spring there is a sharp increase in the relative oxygen content, which in turn is an integral indicator of the intensification of the photosynthesis process and characterizes the degree of productivity of the zones of mixing of sea and river waters.

In summer, due to significant heating and activation of photosynthesis processes by the leading factors in the formation of the oxygen regime, in surface waters are photosynthetic processes, in the bottom - biochemical oxygen consumption by bottom sediments.

Thanks to high temperature water, stratification of the water column, a large influx of organic matter and its intense oxidation, oxygen is rapidly consumed with a minimum supply to the lower layers of the sea, as a result of which a zone of oxygen deficiency is formed in the North Caspian. Intensive photosynthesis in the open waters of the deep-water regions of the Middle and South Caspian covers the upper 25-meter layer, where oxygen saturation is more than 120%.

In autumn, in the well-aerated shallow-water areas of the Northern, Middle and Southern Caspian, the formation of oxygen fields is determined by the processes of water cooling and the less active, but still ongoing process of photosynthesis. The oxygen content is increasing.

The spatial distribution of nutrients in the Caspian Sea reveals the following regularities:

• high concentrations of nutrients are characteristic of the areas of the estuaries of rivers feeding the sea and shallow areas of the sea, subject to active anthropogenic influence (Baku Bay, Turkmenbashy Bay, waters adjacent to Makhachkala, Fort-Shevchenko, etc.);
• The North Caspian, which is a vast area of ​​mixing of river and sea waters, is characterized by significant spatial gradients in the distribution of nutrients;
• in the Middle Caspian, the nature of the circulation contributes to the uplift of deep waters with a high content of nutrients into the overlying layers of the sea;
• in the deep-water regions of the Middle and South Caspian, the vertical distribution of nutrients depends on the intensity of the convective mixing process, and their content increases with depth.

The dynamics of nutrient concentrations throughout the year in the Caspian Sea is influenced by such factors as seasonal fluctuations in the nutrient runoff in the sea, the seasonal ratio of production and destruction processes, the intensity of exchange between soil and water mass, ice conditions in winter in the North Caspian Sea, winter processes. vertical circulation in deep sea areas.

In winter, a significant water area of ​​the North Caspian is covered with ice, but biochemical processes are actively developing in sub-ice water and ice. The ice of the North Caspian, being a kind of accumulator of nutrients, transforms these substances entering the sea from and from the atmosphere.

As a result of the winter vertical circulation of waters in the deep-water regions of the Middle and South Caspian in the cold season, the active layer of the sea is enriched with nutrients due to their supply from the underlying layers.

Spring for the waters of the Northern Caspian is characterized by a minimum content of phosphates, nitrites and silicon, which is explained by the spring outbreak of phytoplankton development (silicon is actively consumed by diatoms). High concentrations of ammonium and nitrate nitrogen, characteristic of the waters of a large area of ​​the Northern Caspian during floods, are due to intensive washing by river waters.

In the spring season, in the area of ​​water exchange between the North and Middle Caspian in the subsurface layer, at the maximum oxygen content, the phosphate content is minimal, which, in turn, indicates the activation of the photosynthesis process in this layer.

In the South Caspian, the distribution of nutrients in spring is basically similar to their distribution in the Middle Caspian.

V summer time redistribution of various forms of biogenic compounds is found in the waters of the Northern Caspian. Here, the content of ammonium nitrogen and nitrates significantly decreases, at the same time, there is a slight increase in the concentrations of phosphates and nitrites and a rather significant increase in the concentration of silicon. In the Middle and South Caspian, the concentration of phosphates decreased due to their consumption in the process of photosynthesis and the difficulty of water exchange with the deep-water accumulation zone.

In the autumn in the Caspian Sea, due to the cessation of the activity of some types of phytoplankton, the content of phosphates and nitrates increases, and the concentration of silicon decreases, as there is an autumn outbreak of the development of diatoms.

For more than 150 years, oil has been produced on the shelf of the Caspian Sea.

Currently, large reserves of hydrocarbons are being developed on the Russian shelf, the resources of which on the Dagestan shelf are estimated at 425 million tons of oil equivalent (of which 132 million tons of oil and 78 billion cubic meters of gas), on the shelf of the North Caspian - 1 billion tons of oil ...

In total, about 2 billion tons of oil have already been produced in the Caspian Sea.

Losses of oil and products of its processing during extraction, transportation and use reach 2% of the total volume.

The main sources of entry of pollutants, including oil products, into the Caspian Sea are removal with river runoff, discharge of untreated industrial and agricultural wastewater, municipal wastewater from cities and villages located on the coast, shipping, exploration and exploitation of oil and gas fields located at the bottom of the sea, transportation of oil by sea. The places of entry of pollutants with river runoff are 90% concentrated in the North Caspian, industrial are confined mainly to the region of the Absheron Peninsula, and increased oil pollution of the South Caspian is associated with oil production and oil exploration drilling, as well as with active volcanic activity (mud) in the zone oil and gas structures.

From the territory of Russia, about 55 thousand tons of oil products are annually delivered to the North Caspian, including 35 thousand tons (65%) from the Volga River and 130 tons (2.5%) from the Terek and Sulak rivers.

Thickening of the film on the water surface up to 0.01 mm disrupts the processes of gas exchange, threatens the death of the hydrobiota. Toxic for fish is the concentration of oil products 0.01 mg / l, for phytoplankton - 0.1 mg / l.

The development of oil and gas resources of the bottom of the Caspian Sea, the projected reserves of which are estimated at 12-15 billion tons of standard fuel, in the coming decades will become the main factor of anthropogenic pressure on the ecosystem of the sea.

Caspian autochthonous fauna... The total number of autochthons is 513 species or 43.8% of the entire fauna, which include herring, gobies, molluscs, etc.

Arctic species. The total number of the Arctic group is 14 species and subspecies, or only 1.2% of the entire fauna of the Caspian Sea (mysids, sea cockroach, white fish, Caspian salmon, Caspian seal, etc.). The basis of the Arctic fauna is made up of crustaceans (71.4%), which easily tolerate desalination and live at great depths in the Middle and South Caspian (from 200 to 700 m), since the lowest water temperatures are kept here throughout the year (4.9– 5.9 ° C).

Mediterranean species... These are 2 types of mollusks, needle-fish, etc. At the beginning of the 20s of our century, the mithielastr mollusk penetrated here, later 2 types of shrimp (with mullet, when acclimatized), 2 types of mullet and flounder. Some species entered the Caspian after the opening of the Volga-Don Canal. Mediterranean species play a significant role in the food supply for fish in the Caspian Sea.

Freshwater fauna (228 species). This group includes anadromous and semi-anadromous fish (sturgeon, salmon, pike, catfish, carp, as well as rotifers).

Marine species... These are ciliates (386 forms), 2 types of foraminifera. There are especially many endemics among higher crustaceans (31 species), gastropods (74 species and subspecies), bivalve molluscs (28 species and subspecies) and fish (63 species and subspecies). The abundance of endemics in the Caspian Sea makes it one of the most original brackish water bodies of the planet.

The Caspian Sea provides over 80% of the world's catches sturgeon fish, most of which are in the North Caspian.

To increase catches of sturgeon, which sharply decreased during the years of falling sea level, a set of measures is being carried out. Among them - a complete ban on fishing sturgeon in the sea and its regulation in rivers, an increase in sturgeon hatchery.

The Caspian Sea is called the most big 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 28m below the level. The water in the Caspian Sea has a lower 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 we take it together with the islands, then more than 7000 km.

The seashore is mostly low and smooth. If you look at the northern part, there are many islands, water channels cut by the Volga and the Urals. In these places, the coast is swampy and covered with thickets. From the east, a semi-desert and desert area 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. The shelf is in the northern part, the average depth here is from 4 to 9 m, the maximum is 24 m, which gradually increases and reaches 100 m. The continental slope in the middle part drops to 500 m. The Mangyshlak sill separates the northern part from the middle. 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 north-west, the length of the coast of 695 km is the territory of Russia. Most of the 2,320 km long coastline belongs to Kazakhstan in the east and northeast. Turkmenistan has 1200 km in the southeastern part, Iran owns 724 km in the south and Azerbaijan owns 955 km of the coastline on the south-western side.

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

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

The largest bays of the Caspian Sea: Agrakhan, Kizlyar, Kaidak, Kazakh, Dead Kultuk, Mangyshlak, Hasan-Kuli, Turkmenbashi, Kazakh, Gyzlar, Anzeli, Astrakhan, Gyzlar.

Until 1980, Kara-Bogaz-Gol was a lagoon bay, which was connected to the sea by a narrow strait. Now it is 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 gets into the lake annually.

Water temperature

The greatest temperature fluctuations are observed during the winter period. 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. Optimum water warming occurs in July-August, in shallow water the temperature reaches 320. But at this time the north-western winds raise cold water layers (upwelling). This process begins in June and reaches its intensity in August. The temperature at the surface of the water is dropping. 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, in the south it is subtropical. On east coast the temperature is always higher than in the west. Once on the east coast, 44 degrees were recorded.

The composition of the Caspian waters

The salinity is about 0.3%. This is a typical desalinated pool. But the further south you go, 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 areas. They arise 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 accounts for almost 80% of all other rivers.

V last years there is a rapid pollution of water with oil products and phenols. Their level has already exceeded the permissible level.

Minerals

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

Fauna and flora

The fauna of the Caspian Sea is up to 1800 species. Of these, 415 are vertebrates, 101 are fish species, there is a world stock of sturgeon. Freshwater fish such as carp, pike perch, roach 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.

Of the plants, blue-green algae, brown, red, can be noted. Zostera and ruppia also grow, they are referred to as flowering algae.

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

Both local and migratory birds can be seen on the coast. In the south, geese and ducks winter, birds such as pelicans, herons, and flamingos arrange nesting grounds.

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

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

Caspian Sea - the largest lake on Earth, endless, located at the junction of Europe and Asia, called the sea because of its size, and also because its bed is folded crust oceanic type. The water in the Caspian is salty, - from 0.05 ‰ near the mouth of the Volga to 11-13 ‰ in the southeast. The water level is subject to fluctuations, according to 2009 data was 27.16 m below sea level. The area of ​​the Caspian Sea is currently about 371,000 km², maximum depth- 1025 m.

Geographical position

The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The length of the Caspian Sea from north to south is about 1200 kilometers (36 ° 34 "-47 ° 13" N), from west to east - from 195 to 435 kilometers, on average 310-320 kilometers (46 ° -56 ° c. d.). The Caspian Sea is conventionally divided by physical and geographical conditions into 3 parts - the North Caspian, the Middle Caspian and the South Caspian. The conditional border between the North and Middle Caspian runs along the line about. Chechnya - Cape Tyub-Karagan, between the Middle and South Caspian - along the line of about. Residential - Cape Gan-Gulu. The area of ​​the North, Middle and South Caspian is 25, 36, 39 percent, respectively.

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 and smooth. In the northern part, the coastline is cut 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 eastern coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of ​​the Absheron Peninsula and on the eastern coast in the area of ​​the Kazakh Bay and Kara-Bogaz-Gol. The territory adjacent to the Caspian Sea is called the Caspian region.

Peninsulas of the Caspian Sea

Major peninsulas of the Caspian Sea:

• Agrakhan Peninsula
• Absheron Peninsula, located on the western coast of the Caspian Sea in the territory of Azerbaijan, at the northeastern end of the Greater Caucasus, on its territory are the cities of Baku and Sumgait
• Buzachi
• Mangyshlak, located on the eastern coast of the Caspian Sea, on the territory of Kazakhstan, on its territory there is the city of Aktau
• Miancale
• Tyub-Karagan

Islands of the Caspian Sea

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

• Ashur-Ada
• Garasu
• Boyuk-Zira
• Zyanbil
• Kur Dashi
• Hara-Zira
• Ogurchinsky
• Sengi-Mugan
• Seal
• Seal Islands
• Chechen
• Chygyl

Bays of the Caspian Sea

Large bays of the Caspian Sea:

• Agrakhan Gulf
• Kizlyar Bay
• Dead Kultuk (former Komsomolets, former Gulf of Tsesarevich)
• Kaydak
• Mangyshlak
• Kazakh
• Kenderli
• Turkmenbashi (bay) (former Krasnovodsk)
• Turkmen (bay)
• Gizilagach (former Kirov Bay)
• Astrakhan (bay)
• Hasan-kuli
• Gyzlar
• Hyrcanus (formerly Astarabad)
• Anzali (formerly Pahlavi)
• Kara-Bogaz-Gol

Rivers flowing into the Caspian Sea- 130 rivers flow into the Caspian Sea, of which 9 rivers have delta-shaped estuaries. Major rivers flowing into the Caspian Sea - Volga, Terek, Sulak, Samur (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Atrek (Turkmenistan), Sefidrud (Iran) and others. The largest river flowing into the Caspian Sea is the Volga, its average annual runoff is 215-224 cubic kilometers. The Volga, Ural, Terek, Sulak and Emba provide up to 88-90% of the annual runoff into the Caspian Sea.

Physiography

Area, depth, volume of water- the area and volume of water in the Caspian Sea varies significantly depending on fluctuations in the water level. With a water level of -26.75 m, the area is approximately 371,000 square kilometers, the volume of water is 78,648 cubic kilometers, which is approximately 44% of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface. In terms of maximum depth, the Caspian Sea is second only to Baikal (1620 m) and Tanganyika (1435 m). The average depth of the Caspian Sea, calculated according to the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

Water level fluctuations- the water level in the Caspian Sea is subject to significant fluctuations. According to modern science Over the past three thousand years, the magnitude of the change in the water level of the Caspian Sea has reached 15 meters. According to archeology and written sources, a high level of the Caspian Sea is recorded at the beginning of the XIV century. Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuation have been conducted since 1837, during this time the highest water level was recorded in 1882 (-25.2 m), the lowest - in 1977 (-29.0 m), with In 1978, the water level increased and in 1995 reached the level of -26.7 m, since 1996, a downward trend has been observed again. Scientists associate the reasons for the change in the water level of the Caspian Sea with climatic, geological and anthropogenic factors. But in 2001, the sea level began to rise again, and reached -26.3 m.

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

Water composition- the salt composition of the waters of the enclosed Caspian Sea differs from that of the ocean. There are significant differences in the ratios of the concentrations of salt-forming ions, especially for the waters of areas under the direct influence of continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total amount of salts of sea waters, an increase in the relative amount of carbonates, sulfates, calcium, which are the main components in chemical composition river waters. The most conservative ions are potassium, sodium, chlorine and magnesium. The least conservative are calcium and bicarbonate ions. In the Caspian, the content of calcium and magnesium cations is almost twice as high as in the Sea of ​​Azov, and the content of sulfate anions is three times higher.

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

Climate- The climate of the Caspian Sea is continental in the northern part, temperate in the middle and subtropical in the southern part. In winter, the average monthly air temperature 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. Maximum temperature+44 degrees recorded on the east coast. Average annual rainfall is 200 millimeters, from 90-100 millimeters in the arid eastern part to 1,700 millimeters off the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea - about 1000 millimeters per year, the most intense evaporation in the area of ​​the Absheron Peninsula and in the eastern part of the South Caspian - up to 1400 millimeters per year. The average annual wind speed is 3-7 meters per second, the wind rose is dominated by north winds... In the autumn and winter months, the winds intensify, the speed of the winds often reaches 35-40 meters per second. The most windy areas are the Apsheron Peninsula, the vicinity of Makhachkala and Derbent, where the most high wave 11 meters high.

Currents- the circulation of waters in the Caspian Sea is associated with runoff and winds. Since most of the runoff is in the North Caspian, northern currents prevail. The intense northern current carries water from the North Caspian along the western coast to the Absheron Peninsula, where the current splits into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.

Economic development of the Caspian Sea

Mining of oil and gas- Many oil and gas fields are being developed in the Caspian Sea. The proven oil resources in the Caspian Sea are about 10 billion tons, the total oil and gas condensate resources are estimated at 18-20 billion tons. Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf near Baku. In the second half of the 19th century, oil production began in industrial volumes on the Absheron Peninsula, then in other territories. In 1949, at Oil Rocks, for the first time, they began to extract oil from the bottom of the Caspian Sea. So, on August 24 this year, Mikhail Kaverochkin's team started drilling a well, which gave the long-awaited oil on November 7 of the same year. In addition to oil and gas production, salt, limestone, stone, sand and clay are also mined on the coast of the Caspian Sea and the Caspian shelf.

Shipping- shipping is developed in the Caspian Sea. Ferry services operate on the Caspian Sea, in particular, Baku - Turkmenbashi, Baku - Aktau, Makhachkala - Aktau. The Caspian Sea has a shipping connection with By the Azov Sea across the Volga, Don and Volga-Don canal.

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

Legal status of the Caspian Sea- after the collapse of the USSR, the division of the Caspian Sea for a long time was and still remains the subject of unresolved disagreements related to the division of the resources of the Caspian shelf - oil and gas, as well as biological resources. For a long time, negotiations were going on between the Caspian states on the status of the Caspian Sea - Azerbaijan, Kazakhstan and Turkmenistan insisted on dividing the Caspian along the median line, Iran - on dividing the Caspian by one fifth between all Caspian states. The current legal regime of the Caspian was established by the Soviet-Iranian treaties of 1921 and 1940. These treaties provide for freedom of navigation throughout the sea, freedom of fishing with the exception of ten-mile national fishing zones and a ban on ships flying the flag of non-Caspian states in its waters. Negotiations on the legal status of the Caspian are currently ongoing.

The Caspian Sea is remarkable in that its western coast belongs to Europe, and the eastern one is located in Asia. This is a huge body of salt water. It is called the sea, but, in fact, it is a lake, since it has no connection with the World Ocean. Therefore, it can be considered the most large lake in the world.

The area of ​​the water giant is 371 thousand square meters. km. As for the depth, the northern part of the sea is rather shallow, while the southern part is deep. The average depth is 208 meters, but it does not give any idea of ​​the thickness of the water mass. The entire reservoir is divided into three parts. These are the North, Middle and South Caspian. The northern one is a sea shelf. It accounts for only 1% of the total volume of water. This part ends behind the Kizlyar Bay near the Chechen island. The average depth in these places is 5-6 meters.

In the Middle Caspian, the seabed is noticeably decreasing, and the average depth reaches 190 meters. The maximum is 788 meters. This part of the sea contains 33% of the total volume of water. And the South Caspian is considered the deepest. It absorbs 66% of the total water mass. The maximum depth was noted in the South Caspian depression. She is equal 1025 meters away and is considered the official maximum sea depth today. The Middle and South Caspian are approximately equal in area and occupy a total of 75% of the area of ​​the entire reservoir.

The maximum length is 1030 km, and the corresponding width is 435 km. The minimum width is 195 km. The average figure is 317 km. That is, the reservoir has an impressive size and is rightfully called the sea. The length of the coastline, together with the islands, reaches almost 7 thousand km. As for the water level, it is below the level of the World Ocean by 28 meters.

The most interesting thing is that the level of the Caspian Sea is subject to cyclicality. The water rises and falls. The water level has been measured since 1837. According to experts, over the past thousand years, the level has fluctuated within 15 meters. This is a very large figure. And they associate it with geological and anthropogenic (human impact on environment) processes. However, it was noted that since the beginning of the 21st century, the level of a huge reservoir has been steadily rising.

5 countries surround the Caspian Sea... These are Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Moreover, Kazakhstan has the longest coastline. Russia is in second place. But the length of the coastal line of Azerbaijan reaches only 800 km, but on the other hand, the largest port in the Caspian Sea is located in this place. This is, of course, Baku. The city is home to 2 million people, and the population of the entire Absheron Peninsula is 2.5 million people.

"Oil Rocks" - a city in the sea
These are 200 platforms with a total length of 350 kilometers.

Notable is the oilmen settlement, which bears the name " Oil Rocks". It is located 42 km east of Absheron in the sea and is a creation of human hands. All residential and industrial buildings are built on metal racks. People serve oil rigs pumping oil from the bowels of the earth. Of course, there are no permanent residents in this village.

In addition to Baku, there are others along the shores of the salt reservoir. big cities... On the southern tip is the Iranian city of Anzali with a population of 111 thousand people. It is the largest Iranian port in the Caspian. Kazakhstan owns the city of Aktau with a population of 178 thousand people. And in the northern part, directly on the Ural River, there is the city of Atyrau. It is inhabited by 183 thousand people.

The Russian city of Astrakhan also has the status of a seaside city, although it is 60 km from the coast and is located in the Volga River delta. it regional center with a population of over 500 thousand people. Directly on the seashore are such Russian cities as Makhachkala, Kaspiysk, Derbent. The latter refers to ancient cities the world. People have been living in this place for over 5 thousand years.

Many rivers flow into the Caspian Sea. There are about 130 of them. The largest of them are the Volga, Terek, Ural, Kura, Atrek, Emba, Sulak. It is the rivers, not precipitation, that feed the huge reservoir. They give him up to 95% of water a year. The basin of the reservoir is 3.626 million square meters. km. These are all rivers with their tributaries flowing into the Caspian. The territory is huge, it includes and Kara-Bogaz-Gol Bay.

It is more correct to call this bay a lagoon. It means a shallow body of water, separated from the sea by a sand bar or reefs. There is such a spit in the Caspian as well. And the strait through which water comes from the sea is 200 km wide. True, people with their restless and ill-considered activities almost destroyed Kara-Bogaz-Gol. They fenced off the lagoon with a dam, and its level plummeted. But after 12 years, the mistake was corrected and the strait was restored.

In the Caspian at all times there was developed shipping... In the Middle Ages, merchants carried exotic spices and skins of snow leopards from Persia to Russia by sea. Today, the reservoir connects the cities located on its banks. Ferry crossings are practiced. There is a water connection with the Black and Baltic Seas through rivers and canals.

Caspian Sea on the map

The reservoir is also important from the point of view fishing, because sturgeon lives in it in large numbers and gives caviar. But today the number of sturgeons has significantly decreased. Environmentalists propose to ban the capture of this valuable fish until the population recovers. But this issue has not yet been resolved. The number of tuna, bream and pike perch also decreased. Here you need to take into account the fact that poaching is highly developed at sea. The reason for it is heavy economic situation region.

And, of course, I need to say a few words about oil... The mining of "black gold" at sea began in 1873. The districts adjacent to Baku have become a real gold mine. There were more than 2 thousand wells here, and oil production and processing was carried out on an industrial scale. At the beginning of the 20th century, it was the center of the international oil industry. In 1920, Azerbaijan was captured by the Bolsheviks. Oil wells and factories were requisitioned. All oil industry came under the control of the USSR. In 1941, Azerbaijan supplied 72% of all oil produced in the socialist state.

In 1994, the "Contract of the Century" was signed. He laid the foundation for the international development of the Baku oil fields. The main Baku-Tbilisi-Ceyhan pipeline allows Azerbaijani oil to flow directly to the Mediterranean port of Ceyhan. It was put into operation in 2006. Today, oil reserves are estimated at 12 trillion. US dollars.

Thus, it is clear that the Caspian Sea is one of the most important economic regions the world. The political situation in the Caspian region is rather complicated. For a long time, there were disputes about the maritime borders between Azerbaijan, Turkmenistan and Iran. There were many inconsistencies, disagreements, which negatively affected the development of the region.

This was ended on August 12, 2018. On this day, the states of the "Caspian Five" signed the Convention on the Legal Status of the Caspian Sea. This document delimited the bottom and subsoil, and each of the five countries (Russia, Kazakhstan, Iran, Turkmenistan, Azerbaijan) received its share in the Caspian basin. The rules for the implementation of navigation, fishing, scientific research, and laying of pipelines were also approved. The boundaries of territorial waters received the status of state ones.

Yuri Syromyatnikov

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 closed 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, currently - about 28 m below the level of the World Ocean.
Square Caspian Sea at present, it is about 371,000 sq km, the maximum depth is 1025 m.

The length of the coastline Caspian Sea estimated at about 6,500 - 6,700 kilometers, with islands up to 7,000 kilometers. The shores Caspian Sea most of its territory is low and smooth. In the northern part, the coastline is cut 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 eastern coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of ​​the Absheron Peninsula and on the eastern coast in the area of ​​the Kazakh Bay and Kara-Bogaz-Gol.

V Caspian Sea 130 rivers flow into the river, of which 9 rivers have delta-shaped estuaries. Large rivers flowing into the Caspian Sea are Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (Russian border with Azerbaijan), Atrek (Turkmenistan) and others.

Caspian Sea Map

The Caspian Sea washes the shores of five coastal states:

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

Water temperature

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

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

Animal world

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

Vegetable world

Vegetable world Caspian Sea and its coastline is represented by 728 species. From plants to Caspian Sea predominantly algae - blue-green, diatomaceous, red, brown, charovy and others, from flowering - zostera and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were introduced into Caspian Sea a person knowingly or on the bottoms of ships.

Mining of oil and gas

V 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 in industrial volumes on the Absheron Peninsula, then in other territories.

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

Ecological problems

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