Caspian Sea (largest lake). Caspian Sea Caspian Sea fresh water

Caspian Sea

The Caspian Sea is one of the most amazing closed bodies of water on Earth.

Over the centuries, the sea has changed more than 70 names. The modern one came from the Caspians - tribes inhabiting the central and southeastern part of Transcaucasia 2 thousand years BC.
Geography Caspian Sea

The Caspian Sea is located at the junction of Europe and Asia and geographical location is divided into the Southern, Northern and Middle Caspian.
Average and Northern part The sea belongs to Russia, the south to Iran, the east to Turkmenistan and Kazakhstan, and the southwest to Azerbaijan.

For many years, the Caspian states have been dividing the Caspian waters among themselves, and quite sharply at that.

Caspian sea map

Lake or sea?

In fact, the Caspian Sea is the world's largest lake, but has a number of marine signs.
These include: a large body of water, strong storms with high waves, high and low tides.

But the Caspian Sea does not have a natural connection with the World Ocean, which makes it impossible to call it a sea.
At the same time, thanks to the Volga and artificially created channels, such a connection appeared.

The salinity of the Caspian Sea is 3 times lower than the usual sea salinity, which does not allow the reservoir to be classified as a sea.

There were times when the Caspian Sea was truly part of the World Ocean.
Several tens of thousands of years ago the Caspian Sea was connected to the Sea of ​​Azov, and through it to the Black and Mediterranean.
As a result of long-term processes occurring in earth's crust, formed Caucasus Mountains, which isolated the reservoir.
The connection between the Caspian and Black Seas was carried out for a long time through the strait (Kuma-Manych depression) and gradually ceased.

Physical quantities

Area, volume, depth

The area, volume and depth of the Caspian Sea are not constant and directly depend on the water level.
On average, the area of ​​the reservoir is 371,000 km², the volume is 78,648 km³ (44% of all world lake water reserves).

The depth of the Caspian Sea in comparison with lakes Baikal and Tanganyika

The average depth of the Caspian Sea is 208 m; the northern part of the sea is considered the shallowest. The maximum depth is 1025 m, noted in the South Caspian depression.
In terms of depth, the Caspian Sea is second only to Baikal and Tanganyika.

The length of the lake from north to south is about 1200 km, from west to east on average 315 km. The length of the coastline is 6600 km, with islands - about 7 thousand km.

Shores

Mostly, the coast of the Caspian Sea is low and smooth.
In the northern part- strongly indented by the river channels of the Urals and Volga. The swampy shores here are located very low.
Eastern Shores adjacent to semi-desert zones and deserts, covered with limestone deposits.
The most winding shores are in the west in the area of ​​the Absheron Peninsula, and in the east in the area of ​​the Kazakh Bay and Kara-Bogaz-Gol.

Sea water temperature

Temperature of the Caspian Sea in different time of the year

Average water temperature in winter in the Caspian Sea it ranges from 0 °C in the northern part to +10 °C in the southern part.
In Iranian waters, the temperature does not drop below +13 °C.
With the onset of cold weather, the shallow northern part of the lake becomes covered with ice, which lasts for 2-3 months. The thickness of the ice cover is 25-60 cm, and at especially low temperatures it can reach 130 cm. Late autumn and in winter, drifting ice floes can be observed in the north.

In summer average temperature The surface water temperature in the sea is + 24 °C.
In most parts the sea warms up to +25 °C…+30 °C.
Warm water and beautiful sandy, occasionally shell and pebble beaches create excellent conditions for a good beach holiday.
In the eastern part of the Caspian Sea, near the city of Begdash, it remains abnormally low water temperature.

Nature of the Caspian Sea

Islands, peninsulas, bays, rivers

The Caspian Sea includes about 50 large and medium-sized islands, with a total area of ​​350 km².
The largest of them are: Ashur-Ada, Garasu, Gum, Dash and Boyuk-Zira. The largest peninsulas are: Agrakhansky, Absheronsky, Buzachi, Mangyshlak, Miankale and Tyub-Karagan.

Tyuleniy Island in the Caspian Sea, part of the Dagestan Nature Reserve

To the largest bays of the Caspian Sea include: Agrakhansky, Kazakh, Kizlyarsky, Dead Kultuk and Mangyshlaksky.
In the east is salt lake Kara-Bogaz-Gol, formerly a lagoon connected to the sea by a strait.
In 1980, a dam was built on it, through which water from the Caspian goes to Kara-Bogaz-Gol, where it then evaporates.

130 rivers flow into the Caspian Sea, located mainly in its northern part. The largest of them are: Volga, Terek, Sulak, Samur and Ural.
The average annual drainage of the Volga is 220 km³. 9 rivers have delta-shaped mouths.

Flora and fauna

The Caspian Sea is home to about 450 species of phytoplankton, including algae, aquatic and flowering plants. Of the 400 species of invertebrates, worms, crustaceans and molluscs predominate. There are a lot of small shrimp in the sea, which are the object of fishing.

More than 120 species of fish live in the Caspian Sea and delta. Fishing objects include sprat (“Kilkin fleet”), catfish, pike, bream, pike perch, kutum, mullet, roach, rudd, herring, white fish, pike perch, goby, grass carp, burbot, asp and pike perch. Stocks of sturgeon and salmon are currently depleted, however, the sea is the largest supplier of black caviar in the world.

Fishing in the Caspian Sea is allowed all year round except for the period from the end of April to the end of June. There are many along the coast fishing bases with all conviniences. Fishing in the Caspian Sea is a great pleasure. In any part of it, including in large cities, the catch is unusually rich.

The lake is famous for its wide variety of waterfowl. Geese, ducks, loons, seagulls, waders, eagles, geese, swans and many others fly to the Caspian Sea during the migration or nesting period.
The largest number of birds - over 600 thousand individuals - is observed at the mouths of the Volga and Ural, in the Turkmenbashi and Kyzylagach bays. During the hunting season, a huge number of fishermen come here not only from Russia, but also from countries near and far abroad.

Caspian seal

The Caspian Sea is home to the only mammal. This is the Caspian seal or seal. Until recently, seals swam close to the beaches, everyone could admire the amazing animal with round black eyes, and the seals behaved very friendly.
Now the seal is on the verge of extinction.

Cities on the Caspian Sea

The largest city on the Caspian Sea coast is Baku.
The number of one of the most the most beautiful cities the world is over 2.5 million people. Baku is located on the picturesque Absheron Peninsula and is surrounded on three sides by the waters of the warm and oil-rich Caspian Sea.
Less big cities: the capital of Dagestan is Makhachkala, the Kazakh Aktau, the Turkmen Turkmenbashi and the Iranian Bender-Anzeli.

Baku Bay, Baku - a city on the Caspian Sea

Interesting Facts

Scientists are still arguing about whether to call a body of water a sea or a lake.
The level of the Caspian Sea is gradually decreasing.
The Volga delivers most of the water to the Caspian Sea.
90% of black caviar is mined in the Caspian Sea. Among them, the most expensive is the albino beluga caviar “Almas” ($2 thousand per 100 g).

Companies from 21 countries are taking part in the development of oil fields in the Caspian Sea. According to Russian estimates, hydrocarbon reserves in the sea amount to 12 billion tons.

American scientists claim that a fifth of the world's hydrocarbon reserves are concentrated in the depths of the Caspian Sea. This is more than the combined reserves of oil-producing countries such as Kuwait and Iraq.

The Caspian Sea is located at the junction of two parts Eurasian continent- Europe and Asia. The Caspian Sea is shaped like the Latin letter S, the length of the Caspian Sea from north to south is approximately 1200 kilometers (36°34" - 47°13" N), from west to east - from 195 to 435 kilometers, on average 310-320 kilometers (46° - 56° E).

The Caspian Sea is conventionally divided according to physical and geographical conditions into 3 parts - the Northern Caspian, the Middle Caspian and the Southern Caspian. The conditional border between the Northern and Middle Caspian Seas passes along the Chechen line (island)- Tyub-Karagansky Cape, between the Middle and Southern Caspian Seas - along the Zhiloi line (island)- Gan-Gulu (Cape). The area of ​​the Northern, Middle and Southern Caspian Sea is 25, 36, 39 percent, respectively.

According to one hypothesis, the Caspian Sea received its name in honor of the ancient tribes of horse breeders - the Caspians, who lived BC on the southwestern coast of the Caspian Sea. Throughout the history of its existence, the Caspian Sea had about 70 names among different tribes and peoples: the Hyrcanian Sea; The Khvalyn Sea or the Khvalis Sea is an ancient Russian name, derived from the name of the inhabitants of Khorezm who traded in the Caspian Sea - Khvalis; Khazar Sea - name in Arabic (Bahr al-Khazar), Persian (Darya-e Khazar), Turkish and Azerbaijani (Khazar denizi) languages; Abeskun Sea; Sarayskoye Sea; Derbent Sea; Sihai and other names. In Iran, the Caspian Sea is still called the Khazar or Mazandaran Sea. (after the name of the people inhabiting the coastal province of Iran of the same name).

The coastline of the Caspian Sea is estimated at approximately 6,500 - 6,700 kilometers, with islands - up to 7,000 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 streams and islands of the Volga and Ural deltas, the banks are low and swampy, and the water surface in many places is covered with thickets. The east 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 Gulf and Kara-Bogaz-Gol.

Large peninsulas of the Caspian Sea: Agrakhan Peninsula, Absheron Peninsula, Buzachi, Mangyshlak, Miankale, Tub-Karagan.

There are about 50 large and medium-sized islands in the Caspian Sea with a total area of ​​approximately 350 square kilometers. Most large islands: Ashur-Ada, Garasu, Gum, Dash, Zira (island), Zyanbil, Kur Dashi, Khara-Zira, Sengi-Mugan, Chechen (island), Chygyl.

Large bays of the Caspian Sea: Agrakhansky Bay, Komsomolets (bay) (formerly Dead Kultuk, formerly Tsesarevich Bay), Kaydak, Mangyshlak, Kazakh (bay), Turkmenbashi (bay) (formerly Krasnovodsk), Turkmen (bay), Gizilagach, Astrakhan (bay), Gyzlar, Girkan (formerly Astarabad) and Anzeli (formerly Pahlavi).

On the eastern coast is the salt lake Kara Bogaz Gol, which until 1980 was a bay-lagoon of the Caspian Sea, connected to it by a narrow strait. In 1980, a dam was built separating Kara-Bogaz-Gol from the Caspian Sea, and in 1984 a culvert was built, after which the level of Kara-Bogaz-Gol dropped by several meters. In 1992, the strait was restored, through which water flows from the Caspian Sea to Kara-Bogaz-Gol and evaporates there. Every year, 8 - 10 cubic kilometers of water flow from the Caspian Sea to Kara-Bogaz-Gol (according to other sources - 25 thousand kilometers) and about 150 thousand tons of salt.

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

The area of ​​the Caspian Sea basin is approximately 3.1 - 3.5 million square kilometers, which is approximately 10 percent of the world's closed water basin area. The length of the Caspian Sea basin from north to south is about 2500 kilometers, from west to east - about 1000 kilometers. The Caspian Sea basin covers 9 states - Azerbaijan, Armenia, Georgia, Iran, Kazakhstan, Russia, Uzbekistan, Turkey and Turkmenistan.

The Caspian Sea washes the shores of five coastal states:

• Russia (Dagestan, Kalmykia and Astrakhan region)- in the trap 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, coastline length - 724 kilometers
• Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

The largest city and port on the Caspian Sea is Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and has a population of 2,070 thousand people. (2003) . Other large Azerbaijani Caspian cities are Sumgait, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near southern border Azerbaijan. To the South-East of the Absheron Peninsula, the oil workers’ village of Neftyanye Kamni is located, the buildings of which stand on artificial islands, overpasses and technological sites.

Large Russian cities- the capital of Dagestan Makhachkala and the most Southern City Russia Derbent - located on the western coast of the Caspian Sea. Astrakhan is also considered a port city of the Caspian Sea, which, however, is not located on the shores of the Caspian Sea, but in the Volga delta, 60 kilometers from north coast Caspian Sea.

On east coast On the Caspian Sea there is a Kazakh city - the port of Aktau, in the north in the Ural delta, 20 km from the sea, the city of Atyrau is located, south of Kara-Bogaz-Gol on the northern shore of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, former Krasnovodsk. Several Caspian cities are located in the southern (Iranian) coast, the largest of them is Anzeli.

The area and volume of water of the Caspian Sea varies significantly depending on fluctuations in water levels. At a water level of −26.75 m, the area was approximately 392,600 square kilometers, the volume of water was 78,648 cubic kilometers, which is approximately 44 percent of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface level. In terms of maximum depth, the Caspian Sea is second only to Lake Baikal (1620 m.) and Tanganyika (1435 m.). The average depth of the Caspian Sea, calculated from the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

The water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past 3 thousand years the amplitude of changes in the water level of the Caspian Sea has been 15 meters. Instrumental measurements of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during which time the highest water level was recorded in 1882 (-25.2 m.), lowest - in 1977 (-29.0 m.), since 1978 the water level has risen and in 1995 reached −26.7 m; since 1996, a downward trend has emerged again. Scientists associate the reasons for changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.

Water temperature is subject to significant latitudinal changes, most clearly expressed 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 water areas with depths less than 25 m, the annual amplitude can reach 25 - 26 °C. On average the water temperature is west coast 1 - 2 °C higher than in the east, and in the open sea the water temperature is 2 - 4 °C higher than on the coasts. Based on the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time periods can be distinguished in the upper 2-meter layer. From October to March, the water temperature increases in the southern and eastern regions, which is especially clearly visible in the Middle Caspian. Two stable quasi-latitudinal zones can be distinguished, where temperature gradients are increased. This is, firstly, the border between the Northern and Middle Caspian, and, secondly, between the Middle and Southern. At the ice edge, in the northern frontal zone, the temperature in February-March increases from 0 to 5 °C, in the southern frontal zone, in the area of ​​the Absheron threshold, from 7 to 10 °C. During this period, the least cooled waters are in the center of the South Caspian Sea, which form a quasi-stationary core. In April-May, the area of ​​minimum temperatures moves to the Middle Caspian Sea, which is associated with faster heating of waters in the shallow northern part of the sea. True, at the beginning of the season in the northern part of the sea a large number of heat is spent on melting the ice, but already in May the temperature here rises to 16 - 17 °C. In the middle part the temperature at this time is 13 - 15 °C, and in the south it increases to 17 - 18 °C. Spring warming of water evens out horizontal gradients, and the temperature difference between coastal areas and the open sea does not exceed 0.5 °C. Warming of the surface layer, which begins in March, disrupts the uniformity of temperature distribution with depth. In June-September, horizontal uniformity in the temperature distribution in the surface layer is observed. In August, which is the month of greatest warming, the water temperature throughout the sea is 24 - 26 °C, and in the southern regions it rises to 28 °C. In August, the water temperature in shallow bays, for example, in Krasnovodsk, can reach 32 °C. The main feature of the water temperature field at this time is upwelling. It is observed annually along the entire eastern coast of the Middle Caspian and partially penetrates even into the Southern Caspian. The rise of cold deep waters occurs with varying intensity as a result of the influence of prevailing summer season northwest winds. The wind in this direction causes the outflow of warm surface waters from the coast and the rise of colder waters from the intermediate layers. Upwelling begins in June, but it reaches its greatest intensity in July-August. As a result, a decrease in temperature is observed on the water surface (7 - 15 °C). Horizontal temperature gradients reach 2.3 °C on the surface and 4.2 °C at a depth of 20 m. The source of upwelling gradually shifts from 41 - 42° N. in June to 43 - 45° N. in September. Summer upwelling is of great importance for the Caspian Sea, radically changing the dynamic processes in the deep-water area. In open areas of the sea, at the end of May - beginning of June, the formation of a temperature jump layer begins, which is most clearly expressed in August. Most often it is located between horizons of 20 and 30 m in the middle part of the sea and 30 and 40 m in the southern part. Vertical temperature gradients in the shock layer are very significant and can reach several degrees per meter. In the middle part of the sea, due to the surge off the eastern coast, the shock layer rises close to the surface. Since in the Caspian Sea there is no stable baroclinic layer with a large reserve of potential energy similar to the main thermocline of the World Ocean, then with the cessation of the prevailing winds causing upwelling and with the beginning of autumn-winter convection in October-November, a rapid restructuring of temperature fields to the winter regime occurs. In the open sea, the water temperature in the surface layer drops in the middle part to 12 - 13 °C, in the southern part to 16 - 17 °C. In the vertical structure, the shock layer is eroded due to convective mixing and disappears by the end of November.

The salt composition of the waters of the closed Caspian Sea differs from the oceanic one. There are significant differences in the ratios of concentrations of salt-forming ions, especially for waters in areas directly influenced by continental runoff. The process of metamorphism 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 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 Sea, the content of calcium and magnesium cations is almost two times higher than in the Sea of ​​Azov, and the sulfate anion is three times higher. Water salinity changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and Ural up to 10 - 11 units. psu on the border with the Middle Caspian. Mineralization in shallow salty bays-kultuks can reach 60 - 100 g/kg. In the Northern Caspian, during the entire ice-free period from April to November, a salinity front of a quasi-latitudinal location is observed. The greatest desalination, associated with the spread of river flow across the sea, is observed in June. The formation of the salinity field in the Northern Caspian Sea is greatly influenced by the wind field. In the middle and southern parts of the sea, salinity fluctuations are small. Basically it is 11.2 - 12.8 units. psu, increasing in the southern and eastern directions. Salinity increases slightly with depth (by 0.1 - 0.2 psu units). In the deep-sea part of the Caspian Sea, in the vertical profile of salinity, characteristic deflections of isohalines and local extrema are observed in the area of ​​the eastern continental slope, which indicate the processes of bottom sliding of waters salinizing in the eastern shallow waters of the South Caspian. The salinity value also strongly depends on sea level and (which is related) on the volume of continental runoff.

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

The climate of the Caspian Sea is continental in the northern part, temperate in the middle and subtropical in the southern part. In winter average monthly temperature 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 maximum temperature recorded on the east coast was 44 degrees.

The average annual precipitation is 200 millimeters per year, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters along the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea is 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 Sea is up to 1400 millimeters per year.

Winds often blow on the territory of the Caspian Sea, their average annual speed is 3-7 meters per second, the wind rose is dominated by north winds. In the autumn and winter months, winds become stronger, with wind speeds often reaching 35-40 meters per second. The most windy territories are the Absheron Peninsula and the environs of Makhachkala - Derbent, where the most high wave- 11 meters.

Water circulation in the Caspian Sea is related to runoff and winds. Because the most of The drainage falls on the Northern Caspian Sea, northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current divides into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.

The fauna of the Caspian Sea is represented by 1810 species, of which 415 are vertebrates. 101 species of fish are registered in the Caspian world, where most of the world's sturgeon reserves are concentrated, as well as freshwater fish such as roach, carp, and pike perch. The Caspian Sea is the habitat of fish such as carp, mullet, sprat, kutum, bream, salmon, perch, and pike. The Caspian Sea is also home to a marine mammal - the Caspian seal. Since March 31, 2008, 363 dead seals have been found on the coast of the Caspian Sea in Kazakhstan.

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

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

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

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

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

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

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

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

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

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

During major north shore The Caspian Sea shifted to Samara Luka on the Volga, and maybe further. During maximum transgressions, the Caspian Sea turned into a drainage lake: excess water flowed through the Kuma-Manych depression into the Sea of ​​Azov and further into the Black Sea. In extreme regressions South coast The Caspian Sea shifted to the Absheron threshold.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Many geographical names, can mislead people who are not keen on geography. Could it be that an object marked on all maps as a sea is actually a lake? Let's figure it out.

The history of the appearance of the Caspian Sea?

14,000,000 years ago, the Sarmatian Sea existed on the planet. It included the modern Black, Caspian and Azov seas. About 6,000,000 years ago, due to the rise of the Caucasus Mountains and the decrease in water levels in the Mediterranean Sea, it divided, forming four different seas.

The Caspian is inhabited by many representatives of the fauna of Azov, which once again confirms that these reservoirs were once one whole. This is one of the reasons why the Caspian Sea is considered a lake.

The name of the sea comes from the ancient tribes of the Caspian Sea. They inhabited its shores in the first millennia BC and were engaged in horse breeding. But over the many hundreds of years of its existence, this sea has had many names. It was called Derbentsky, Saraisky, Girkansky, Sigai, Kukkuz. Even in our time, for residents of Iran and Azerbaijan, this lake is called Khazar.

Geographical location

Two parts of the world - Europe and Asia - are washed by the waters of the Caspian Sea. The coastline covers the following countries:

• Turkmenistan
• Russia
• Azerbaijan
• Kazakhstan

The length from north to south is about one thousand two hundred kilometers, the width from west to east is about three hundred kilometers. The average depth is about two hundred meters, the greatest depth is about a thousand kilometers. total area The reservoir covers more than 370,000 square kilometers and is divided into three climatic and geographical zones:

1. Northern
2. Average
3. Southern Caspian

The water area includes six large peninsulas and about fifty islands. Their total area is four hundred square kilometers. The largest islands are Dzhambaisky, Ogurchinsky, Chechen, Tyuleniy, Konevsky, Zyudev and the Absheron Islands. About one hundred and thirty rivers flow into the Caspian Sea, including the Volga, Ural, Atrek, Sefirud, Terek, Kura and many others.

Sea or lake?

The official name used in documentation and cartography is the Caspian Sea. But is this true?

In order to have the right to be called a sea, any body of water must be connected to the world's oceans. In the case of the Caspian Sea, this is not reality. The Caspian Sea is separated by almost 500 km of land from the nearest sea, the Black Sea. This is a completely enclosed body of water. The main differences between the seas:

• The seas can be fed by waterways - rivers.
• The external seas are directly connected to the ocean, that is, they have access to it.
• Inland seas are connected to other seas or oceans by straits.

The Caspian received the right to be called a sea primarily because of its impressive size, which is more typical of seas rather than lakes. In area it surpasses even Azov. Also no small role was played by the fact that not a single lake washes the shores of five states at once.

It is worth noting that the structure of the Caspian Sea bottom is of the oceanic type. This happened due to the fact that it was once part of the ancient World Ocean.

Compared to other seas, the percentage of salt saturation in it is very weak and does not exceed 0.05%. The Caspian Sea is fed only by rivers flowing into it, like all lakes on the globe.

Like many seas, the Caspian is famous for its powerful storms. The height of the waves can reach eleven meters. Storms can occur at any time of the year, but they are most dangerous in autumn and winter.

In fact, the Caspian Sea is the most big lake in the world. Its waters are not subject to international maritime laws. The territory of waters is divided between countries on the basis of laws adopted for lakes, and not for seas.

The Caspian Sea has rich mineral resources such as oil and gas. Its waters are inhabited by more than one hundred and twenty species of fish. Among them are the most valuable sturgeons, such as stellate sturgeon, sturgeon, sterlet, beluga, and thorn. 90% of the world's sturgeon catch comes from the Caspian Sea.

Interesting features:

• Scientists around the world have not yet come to a clear conclusion as to why the Caspian Sea is considered a lake. Some experts even suggest considering it a “lake-sea” or an “inland” sea, like the Dead Sea in Israel;
• The most deep point Caspian Sea - more than one kilometer;
• Historically, it is known that the total water level in the reservoir has changed more than once. The exact reasons for this are still not understood;
• It is the only body of water separating Asia and Europe;
• The largest water artery feeding the lake is the Volga River. It is this that carries the bulk of the water;
• Thousands of years ago the Caspian Sea was part of the Black Sea;
• In terms of the number of fish species, the Caspian Sea is inferior to some rivers;
• The Caspian Sea is the main supplier of the most expensive delicacy - black caviar;
• The water in the lake is completely renewed every two hundred and fifty years;
• The territory of Japan is smaller than the area of ​​the Caspian Sea.

Ecological situation

Intervention into the ecology of the Caspian Sea regularly occurs due to the extraction of oil and natural resources. There are also interventions in the fauna of the reservoir, cases of poaching and illegal fishing of valuable fish species are frequent.

The water level in the Caspian Sea is falling every year. This is due to global warming, due to the influence of which the water temperature on the surface of the reservoir increased by one degree and the sea began to actively evaporate.

It is estimated that water levels have fallen by seven centimeters since 1996. By 2015, the level of the fall was about one and a half meters, and the water continues to fall.

If this continues, in a century the shallowest part of the lake may simply disappear. This will be the part that washes the borders of Russia and Kazakhstan. If global warming intensifies, the process may accelerate and this will happen much earlier.

It is known that long before the onset of global warming, the water level in the Caspian Sea underwent changes. The water kept rising and then falling. Scientists still cannot say exactly why this happened.

, Kazakhstan, Turkmenistan, Iran, Azerbaijan

Geographical position

Caspian Sea - view from space.

The Caspian Sea is located at the junction of two parts of the Eurasian continent - Europe and Asia. The length of the Caspian Sea from north to south is approximately 1200 kilometers (36°34"-47°13" N), from west to east - from 195 to 435 kilometers, on average 310-320 kilometers (46°-56° c. d.).

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

Coast of the Caspian Sea

Coast of the Caspian Sea in Turkmenistan

The territory adjacent to the Caspian Sea is called the Caspian region.

Peninsulas of the Caspian Sea

• Ashur-Ada
• Garasu
• Zyanbil
• Khara-Zira
• Sengi-Mugan
• Chygyl

Bays of the Caspian Sea

• Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and northwest, the length of the coastline is about 1930 kilometers
• Kazakhstan - in the north, northeast and east, the length of the coastline is about 2320 kilometers
• Turkmenistan - in the southeast, the length of the coastline is about 650 kilometers
• Iran - in the south, the length of the coastline is about 1000 kilometers
• Azerbaijan - in the southwest, the length of the coastline is about 800 kilometers

Cities on the Caspian Sea coast

On the Russian coast are the cities of Lagan, Makhachkala, Kaspiysk, Izberbash and the southernmost city of Russia, Derbent. Astrakhan is also considered a port city of the Caspian Sea, which, however, is not located on the shores of the Caspian Sea, but in the Volga delta, 60 kilometers from the northern coast of the Caspian Sea.

Physiography

Area, depth, volume of water

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

Water level fluctuations

Vegetable world

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

History of the Caspian Sea

Origin of the Caspian Sea

Anthropological and cultural history of the Caspian Sea

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

Research of the Caspian Sea

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

Economy of the Caspian Sea

Mining of oil and gas

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

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

Shipping

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

Fishing and seafood production

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

Recreational resources

Natural environment of the Caspian coast with sandy beaches, mineral waters and healing mud in the coastal zone creates good conditions for rest and treatment. At the same time, in terms of the degree of development of resorts and the tourism industry, the Caspian coast is noticeably inferior to the Black Sea coast of the Caucasus. At the same time, in last years The tourism industry is actively developing on the coasts of Azerbaijan, Iran, Turkmenistan and Russian Dagestan. In Azerbaijan, the resort area in the Baku region is actively developing. At the moment, a world-class resort has been created in Amburan, another modern tourist complex is being built in the area of ​​​​the village of Nardaran, and holidays in the sanatoriums of the villages of Bilgah and Zagulba are very popular. A resort area is also being developed in Nabran, in northern Azerbaijan. However high prices, in general, the low level of service and lack of advertising lead to the fact that there are almost no foreign tourists at the Caspian resorts. The development of the tourism industry in Turkmenistan is hampered by a long-term policy of isolation, in Iran - Sharia laws, due to which mass holidays of foreign tourists on the Caspian coast of Iran are impossible.

Ecological problems

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

International status of the Caspian Sea

Legal status of the Caspian Sea

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

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

The current legal regime of the Caspian Sea was established by the Soviet-Iranian treaties of 1921 and 1940. These treaties provide for freedom of navigation throughout the sea, freedom of fishing with the exception of ten-mile national fishing zones and a ban on vessels flying the flag of non-Caspian states sailing in its waters.

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

Delineation of sections of the Caspian seabed for subsoil use

The Russian Federation concluded an agreement with Kazakhstan on delimiting the bottom of the northern part of the Caspian Sea in order to exercise sovereign rights to subsoil use (dated July 6, 1998 and the Protocol thereto dated May 13, 2002), an agreement with Azerbaijan on delimiting adjacent areas of the bottom of the northern part of the Caspian Sea (dated September 23, 2002), as well as the trilateral Russian-Azerbaijani-Kazakh agreement on the junction point of the demarcation lines of adjacent sections of the Caspian Sea bottom (dated May 14, 2003), which established geographical coordinates dividing lines limiting the areas of the seabed within which the parties exercise their sovereign rights in the field of exploration and production of mineral resources.