Resources of the Caspian Sea. A brief description of. Caspian Sea. A small sea or a huge lake? (3 photos)

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

Meanwhile, it is really more correct to call the Caspian a lake, not a sea. Why? Let's figure it out.

A bit of geography. Where is the Caspian Sea located?

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

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

Why is the Caspian called a lake?

The main feature of any sea is the presence of straits connecting it with the ocean. The Caspian is a closed, or endorheic body of water, which receives river water, but does not connect with any ocean.


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

The waters of the Caspian Sea are not subject to international maritime laws, and its water area is divided among all countries that adjoin it, in proportion to the coastline.

Why is the Caspian called the sea?

Despite all of the above, most often in geography, as well as in international and domestic documents, the name “Caspian Sea” is used, and not “Caspian Lake”. First of all, this is due to the size of the reservoir, which is much more typical for the sea than for the lake. Even, which is much smaller in area than the Caspian, the locals often call the sea. There are no other lakes in the world whose shores belong to five different countries at the same time.

In addition, attention should be paid to the structure of the bottom, which near the Caspian Sea has a pronounced oceanic type. Once the Caspian Sea, most likely, was connected with the Mediterranean, but tectonic processes and drying up separated it from the World Ocean. More than fifty islands are located in the Caspian Sea, and the area of ​​some of them is quite large, even by international standards they are considered large. All this makes it possible to call the Caspian a sea, not a lake.

origin of name

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


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

The Caspian Sea is located in different geographical zones. It plays a big role in world history, is an important economic region and a source of resources. The Caspian Sea is a unique body of water.

Short description

This sea is large. The bottom is covered with oceanic bark. These factors make it possible to classify it as a sea.

It is a closed reservoir, has no drains and is not connected with the waters of the oceans. Therefore, it can also be attributed to the category of lakes. In this case, it will be the largest lake on the planet.

The approximate area of ​​the Caspian Sea is about 370 thousand square kilometers. The volume of the sea changes depending on the various fluctuations in the water level. The average value is 80 thousand cubic kilometers. The depth varies in its parts: the southern one has a greater depth than the northern one. The average depth is 208 meters, the highest value in the southern part exceeds 1000 meters.

The Caspian Sea plays an important role in the development of trade relations between the countries. The resources mined in it, as well as other trade items, have been transported to different countries since the development of navigation at sea. Since the Middle Ages, merchants have delivered exotic goods, spices and furs. Today, in addition to transporting resources, ferries between cities are carried out by sea. The Caspian Sea is also connected by a navigable canal through the rivers with the Sea of ​​Azov.

Geographic characteristics

The Caspian Sea is located between two continents - Europe and Asia. Washes the territory of several countries. These are Russia, Kazakhstan, Iran, Turkmenistan and Azerbaijan.

It has more than 50 islands, both large and small in size. For example, the islands of Ashur-Ada, Tyuleniy, Chigil, Gum, Zenbil. As well as the peninsulas, the most significant - Absheron, Mangyshlak, Agrakhan and others.

The Caspian Sea receives the main influx of water resources from the rivers flowing into it. In total, there are 130 tributaries of this reservoir. The largest is the Volga River, which brings the bulk of the water. The Kheras, Ural, Terek, Astarchay, Kura, Sulak and many others rivers also flow into it.

The waters of this sea form many bays. Among the largest are: Agrakhansky, Kizlyarsky, Turkmenbashi, Girkan Bay. In the eastern part there is a bay-lake called Kara-Bogaz-Gol. It communicates with the sea by a small strait.

Climate

The climate is characterized by the geographical location of the sea, therefore it has several types: from continental in the northern region to subtropical in the south. This affects the air and water temperatures, which have great contrasts depending on the part of the sea, especially in the cold season.

In winter, the average air temperature in the northern region is about -10 degrees, the water reaches -1 degrees.

In the southern region, the temperature of air and water in winter warms up to an average of +10 degrees.

In summer, the air temperature in the northern zone reaches +25 degrees. Much hotter in the south. The maximum recorded value here is + 44 degrees.

Resources

The natural resources of the Caspian Sea contain large reserves of various deposits.

One of the most valuable resources of the Caspian Sea is oil. Mining has been carried out since about 1820. Springs were opened on the territory of the seabed and its coast. By the beginning of the new century, the Caspian was at the forefront in obtaining this valuable product. During this time, thousands of wells were opened, which made it possible to extract oil on a huge industrial scale.

The Caspian Sea and the territory adjacent to it also have rich deposits of natural gas, mineral salts, sand, lime, several types of natural clay and rocks.

Inhabitants and fisheries

The biological resources of the Caspian Sea are very diverse and highly productive. It contains more than 1500 species of inhabitants, rich in commercial fish species. Population depends on climatic conditions in different parts of the sea.

In the northern part of the sea, pike perch, bream, catfish, asp, pike and other species are more common. Gobies, mullet, bream, herring live in the western and eastern. Southern waters are rich in various representatives. One of the many are sturgeons. According to their content, this sea occupies a leading place among other reservoirs.

Among the wide variety, tuna, beluga, stellate sturgeon, sprat and many others are also caught. In addition, there are mollusks, crayfish, echinoderms and jellyfish.

The mammal Caspian seal lives in the Caspian Sea, or This animal is unique and lives only in these waters.

The sea is also characterized by a high content of various algae, for example, blue-green, red, brown; sea ​​grass and phytoplankton.

Ecology

The extraction and transportation of oil has a huge negative impact on the ecological situation of the sea. The ingress of oil products into water is almost inevitable. Oil stains cause irreparable damage to marine habitats.

The main inflow of water resources to the Caspian Sea is provided by rivers. Unfortunately, most of them have a high level of pollution, which degrades the quality of the water in the sea.

Industrial and domestic effluents from the surrounding cities are poured into the sea in large quantities, which also damages the environment.

Poaching causes great damage to the marine habitat. Sturgeon species are the main target for illegal catching. This significantly reduces the number of sturgeon and threatens the entire population of this type.

The above information will help to assess the resources of the Caspian Sea, to briefly study the characteristics and ecological situation of this unique reservoir.

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

The area of ​​the sea 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 landscapes, climatic conditions and types of rivers are different. Despite its vastness, only 62.6% of its area is in waste areas; about 26.1% - for drainless. 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 coast 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 water entering the sea (it should be noted that more than 25% of the Russian economy is located in the basin of this river, and this undoubtedly determines many other features of the waters of the Caspian Sea), as well as the Kura River , Zhaiyk (Ural), Terek, Sulak, Samur.

In physical and geographical terms and according to the nature of the underwater relief, the sea is divided into three parts: northern, middle and southern. The conditional boundary between the northern and middle parts runs along the line of Chechen Island–Cape Tyub-Karagan, between the middle and southern parts - along the line of Zhiloy Island–Cape Kuuli.

The shelf of the Caspian Sea, on average, is limited to depths of about 100 m. The continental slope, which begins below the edge of the shelf, ends in the middle part at about 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, the 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, furrows.

The middle part of the sea is a separate basin, the region of maximum depths of which - the Derbent depression - 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 part by the Apsheron threshold, which is a continuation of the Greater Caucasus. Depths above this underwater ridge do not exceed 180 m. The deepest part of the South Caspian basin with a maximum sea depth of 1025 m 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 quite strongly indented. Here are the bays of Kizlyar, Agrakhan, Mangyshlak and many shallow bays. Notable peninsulas: Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak. Large islands in the northern part of the sea are 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 on other parts of the coastline.

The middle part of the sea has a relatively flat coastline. On the western coast, on the border with the southern part of the sea, the Apsheron Peninsula is located. To the east of it, islands and banks of the Apsheron archipelago stand out, of which the largest is Zhiloy Island. The eastern shore of the Middle Caspian is more indented, the Kazakh Bay stands out here with the Kenderli Bay and several capes. The largest bay of this coast is Kara-Bogaz-Gol.

South of the Absheron Peninsula are the islands of the Baku archipelago. 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 at the bottom of the sea. On the eastern shore are the large bays of Turkmenbashi and Turkmensky, and near it is the island of Ogurchinsky.

One of the most striking phenomena of the Caspian Sea is the periodic variability of its level. In historical times, the Caspian Sea had a lower level 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) of the sea level, the amplitude of its fluctuations has been 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 has changed significantly twice. In 1929 it stood at a mark of about -26 m, and since it had been close to this mark for almost a century, this position of the level was considered as a long-term or secular average. In 1930, the level began to decline rapidly. Already by 1941, it had dropped by almost 2 m. This led to the drying up of vast coastal areas of the bottom. The decrease in the level, with its small fluctuations (short-term insignificant rises in the level in 1946-1948 and 1956-1958), continued until 1977 and reached the mark of -29.02 m, i.e., the level took the lowest position for 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 has risen by more than 2 m. The rate of this rise is 15 cm per year. The level increment in some years was higher, and in 1991 it reached 39 cm.

The general fluctuations in the level of the Caspian Sea are superimposed by its seasonal changes, the average long-term of which reaches 40 cm, as well as surge phenomena. The latter are especially pronounced in the Northern Caspian. The northwestern coast is characterized by large surges created by the prevailing, especially in the cold season, storms of eastern and southeastern directions. Over the past decades, a number of large (more than 1.5–3 m) surges have been observed here. A particularly 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 zones. 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, easterly winds prevail throughout the year (the influence of the Asian high). The position at rather low latitudes provides a positive balance of heat inflow, so the Caspian Sea serves as a source of heat and moisture for passing air masses for most of the year. The average annual temperature in the northern part of the sea is 8–10°С, in the middle part - 11–14°С, in the southern part – 15–17°С. However, in the northernmost parts of the sea, the average January temperature is from –7 to –10°C, and the minimum temperature during arctic air intrusions is up to –30°C, which determines the formation of the ice cover. In summer, rather high temperatures dominate over the entire region under consideration - 24–26°С. Thus, the Northern Caspian is subject to the most sharp temperature fluctuations.

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

Water temperature. The distinctive features of the Caspian Sea (great differences in depths in different parts of the sea, the nature of the bottom relief, isolation) have a certain influence on the formation of temperature conditions. In the shallow North Caspian, the entire water column can be considered 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 separated by a transitional layer can be distinguished. In the Northern Caspian and in the surface layers of the Middle and Southern Caspian, the water temperature varies over a wide range. In winter, temperatures vary from north to south from less than 2 to 10°С, the water temperature near the western coast is 1–2°С higher than near the eastern one, in the open sea the temperature is higher than near 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. During moderate and severe winters in the northern part of the sea and shallow bays on the east coast, the water temperature drops to freezing.

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

Salinity. 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 of the Northern Caspian and between the Northern and Middle Caspian, the bottom topography, which determines the location of waters with different salinity, mainly along the isobaths, evaporation, which ensures the shortage of fresh water and the inflow of more saline ones. These factors collectively affect the seasonal differences in salinity.

The Northern Caspian can be considered as a reservoir of constant mixing of river and Caspian waters. The most active mixing occurs in the western part, where both river and Central Caspian waters directly enter. In this case, horizontal salinity gradients can reach 1‰ per 1 km.

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

According to the values ​​of horizontal salinity gradients, in the western part of the Northern Caspian, a river-sea contact zone can be distinguished with water salinity from 2 to 10‰, in the eastern part from 2 to 6‰.

Significant vertical salinity gradients in the Northern Caspian are formed as a result of the interaction of river and sea waters, with runoff playing a decisive role. The intensification of vertical stratification is also facilitated by the unequal thermal state of the water layers, since the temperature of the surface desalinated waters coming from the coast in summer is 10–15°C higher than that of the bottom ones.

In the deep basins of the Middle and South Caspian, salinity fluctuations in the upper layer are 1–1.5‰. The largest difference between the maximum and minimum salinity was noted in the area of ​​the Apsheron threshold, 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 runoff of the Kura River. The influence of the Kura runoff decreases with depth; at the horizons of 40–70 m, the range of salinity fluctuations is no more than 1.1‰. Along the entire western coast to the Absheron Peninsula stretches a strip of desalinated water with a salinity of 10–12.5‰ coming from the Northern Caspian.

In addition, salinity increases in the South Caspian due to the removal of saline waters from bays and inlets on the eastern shelf under the action of southeasterly winds. In the future, 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 part of the South Caspian, the upper boundary of waters with increased salinity drops to 250 m. Obviously, vertical mixing of waters is difficult in these parts of the sea.

Surface water circulation. Currents in the sea are mainly wind-driven. In the western part of the Northern Caspian, 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 can be traced only within the estuarine coast. The prevailing current velocities are 10–15 cm/s; in the open areas 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, currents of the northwestern, northern, southeastern, and southern directions are observed in accordance with the wind directions; eastward currents often occur near the eastern coast. Along the western coast of the middle part of the sea, the most stable currents are southeast and south. Current velocities 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 ones.

ice formation. The Northern Caspian is covered with ice annually in November, the area of ​​the freezing part of the water area depends on the severity of the winter: in severe winters, the entire Northern Caspian is covered with ice, in soft ice it stays within the 2–3 meter isobath. The appearance of ice in the middle and southern parts of the sea falls on December-January. Near the eastern coast, ice is of local origin, near the western coast - most often brought from the northern part of the sea. In severe winters, shallow bays freeze off the eastern coast of the middle part of the sea, coasts and landfast ice form off the coast, and drift ice spreads to the Absheron Peninsula in abnormally cold winters off the western coast. 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 distribution of oxygen. An increased oxygen content is found in the areas of the pre-estuary seashore of the Volga River, a lower one - in the southwestern part of the Northern Caspian.

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

In the deep-water regions of the Caspian Sea, the main pattern is preserved 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 flow of North Caspian waters with a high oxygen content along the continental slope to significant depths of the Caspian Sea.

The seasonal distribution of oxygen is mainly related to the annual course and seasonal ratio of production-destruction processes occurring in the sea.

In spring, the production of oxygen in the process of photosynthesis quite significantly covers the decrease in oxygen due to a decrease in its solubility with an increase in water temperature in spring.

In the areas of the estuarine coasts of the 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 mixing zones of sea and river waters.

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

Due to the high temperature of the waters, the stratification of the water column, the large influx of organic matter and its intense oxidation, oxygen is quickly consumed with its minimal entry into the lower layers of the sea, as a result of which an oxygen deficiency zone is formed in the Northern 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 rising.

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

• increased concentrations of biogenic substances characterize the areas of pre-estuary seashores of rivers that feed the sea and shallow areas of the sea subject to active anthropogenic influence (Baku Bay, Turkmenbashi Bay, water areas adjacent to Makhachkala, Fort Shevchenko, etc.);
• The Northern Caspian, which is a vast mixing zone of river and sea waters, is characterized by significant spatial gradients in the distribution of nutrients;
• in the Middle Caspian, the cyclonic nature of the circulation contributes to the upwelling of deep waters with a high content of nutrients into the overlying layers of the sea;
• in the deep water areas 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 during the year in the Caspian Sea is influenced by such factors as seasonal fluctuations in the biogenic runoff into the sea, the seasonal ratio of production-destruction processes, the intensity of exchange between soil and water mass, ice conditions in winter in the Northern Caspian, the processes of winter vertical circulation in the deep sea areas.

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

As a result of the winter vertical circulation of waters in the deep-sea regions of the Middle and Southern 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 North 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 flushing by river waters.

In the spring season, in the area of ​​water exchange between the Northern and Middle Caspian in the subsurface layer, with the maximum oxygen content, the content of phosphates 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.

In the summertime, the waters of the Northern Caspian reveal a redistribution of various forms of biogenic compounds. Here, the content of ammonium nitrogen and nitrates significantly decreases, while 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 has decreased due to their consumption in the process of photosynthesis and the difficulty of water exchange with the deep water accumulation zone.

In 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 an autumn outbreak of diatoms occurs.

Oil has been produced on the shelf of the Caspian Sea for more than 150 years.

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 m3 of gas), on the shelf of the Northern Caspian - 1 billion tons of oil .

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

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

The main sources of pollutants, including oil products, entering the Caspian Sea are carry-over with river runoff, discharge of untreated industrial and agricultural effluents, domestic wastewater from cities and towns 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. 90% of pollutants with river runoff are concentrated in the Northern Caspian, industrial effluents are confined mainly to the area of ​​the Apsheron Peninsula, and increased oil pollution of the Southern Caspian is associated with oil production and oil exploration drilling, as well as active volcanic activity (mud) in zone of oil and gas bearing structures.

From the territory of Russia, about 55 thousand tons of oil products enter the Northern Caspian every year, including 35 thousand tons (65%) from the Volga River and 130 tons (2.5%) from the Terek and Sulak rivers.

The thickening of the film on the water surface up to 0.01 mm disrupts the processes of gas exchange and threatens the death of 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 estimated reserves of which are estimated at 12–15 billion tons of standard fuel, will become the main factor in the anthropogenic load on the ecosystem of the sea in the coming decades.

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

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

mediterranean views. These are 2 types of mollusks, needle-fish, etc. At the beginning of the 20s of our century, the mollusk mitilyastra penetrated here, later 2 types of shrimp (with mullets, during their acclimatization), 2 types of mullet and flounder. Some Mediterranean species entered the Caspian after the opening of the Volga-Don Canal. Mediterranean species play a significant role in the fish food base of the Caspian Sea.

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

sea ​​views. These are ciliates (386 forms), 2 species of foraminifera. There are especially many endemics among higher crustaceans (31 species), gastropod molluscs (74 species and subspecies), bivalve mollusks (28 species and subspecies) and fish (63 species and subspecies). The abundance of endemics in the Caspian Sea makes it one of the most unique brackish water bodies on the planet.

The Caspian Sea provides more than 80% of the world's sturgeon catch, most of which falls on the North Caspian.

To increase the catches of sturgeon, which dropped sharply during the years of sea level drop, a set of measures is being implemented. Among them - a complete ban on sturgeon fishing in the sea and its regulation in rivers, an increase in the scale of factory breeding of sturgeons.

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.

Caspian Sea

The Caspian Sea is the largest lake on Earth, located at the junction of Europe and Asia, called the sea because of its size. The Caspian Sea is an endorheic 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. The area of ​​the Caspian Sea is currently approximately 371,000 sq. km, the maximum depth is 1025 m.

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.

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

The Caspian Sea washes the shores of five coastal states:

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

Water temperature

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

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

Animal world

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

Vegetable world

The flora of the Caspian Sea and its coast is represented by 728 species. Of the plants in the Caspian Sea, algae predominate - blue-green, diatoms, red, brown, char and others, of flowering - zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought into the Caspian Sea by man either consciously or on the bottoms of ships.

Mining of oil and gas

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

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

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