The Caspian Sea is all about it. Caspian Sea or Lake? Recreational resources of the Caspian lake

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

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

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

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

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

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

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

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

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

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

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

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

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

Caspian Sea on the map

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

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

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

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

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

Yuri Syromyatnikov

The Caspian Sea is located on the border of Europe and Asia and is surrounded by the territories of five states: Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan. Despite the name, the Caspian is the largest lake on the planet (its area is 371,000 km2), but the bottom, formed by the oceanic crust, and salt water, together with its large size, give reason to consider it as a sea. A large number of rivers flow into the Caspian Sea, for example, such large ones as the Volga, Terek, Ural, Kura and others.

Relief and depth of the Caspian Sea

According to the bottom relief, the Caspian Sea is divided into three parts: southern (the largest and deepest), middle and northern.

In the northern part, the depth of the sea is the smallest: on average, it ranges from four to eight meters, and the maximum depth here reaches 25 m. The northern part of the Caspian Sea is limited by the Mangyshlak Peninsula and occupies 25% of the entire area of ​​the reservoir.

The middle part of the Caspian Sea is deeper. Here the average depth is already equal to 190 m, while the maximum is 788 meters. The area of ​​the middle Caspian Sea is 36% of the total, and the volume of water is 33% of the total volume of the sea. It is separated from the southern part by the Absheron Peninsula in Azerbaijan.

The deepest and largest part of the Caspian Sea is the southern one. It occupies 39% of the total area, and its share of the total water volume is 66%. Here is the South Caspian depression, in which the deepest point of the sea is located - 1025 m.

Islands, peninsulas and bays of the Caspian Sea

In total, there are about 50 islands in the Caspian Sea, almost all of them are uninhabited. Due to the shallower depth of the northern part of the sea, most of the islands are located there, including the Baku archipelago belonging to Azerbaijan, the Seal Islands in Kazakhstan, as well as many Russian islands off the coast of the Astrakhan region and Dagestan.

Among the peninsulas of the Caspian Sea, the largest are Mangyshlak (Mangistau) in Kazakhstan and Absheron in Azerbaijan, where such large cities as the capital of the country Baku and Sumgait are located.

Gulf of Kara-Bogaz-Gol Caspian Sea

The coastline of the sea is strongly indented, and there are many bays on it, for example, Kizlyar, Mangyshlak, Dead Kultuk and others. The Kara-Bogaz-Gol Bay deserves a special mention, which is actually a separate lake connected to the Caspian by a narrow strait, due to which a separate ecosystem and higher water salinity are preserved in it.

Fishing in the Caspian Sea

The Caspian Sea has long attracted the inhabitants of its shores with its fish resources. Here, about 90% of all world sturgeon production is caught, as well as fish such as carp, bream, sprat.

Caspian Sea video

In addition to fish, the Caspian is extremely rich in oil and gas, the total reserves of which are about 18-20 million tons. Salt, limestone, sand and clay are also mined here.

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The program of celebration of the Day of the Caspian Sea has begun in Astrakhan today. Such holidays are celebrated in five Caspian states. Although the Caspian in modern conditions requires not so much festive events as respect from everyone who inhabits its shores and exploits its wealth.

“Caspian News”, of course, cannot stand aside, because the attitude towards the Caspian Sea is in the very name and ideology of our portal. Our story about a unique reservoir is a kind of tribute to the “hero of the occasion”.

The uniqueness of the Caspian Sea lies, first of all, in the fact that it is not a sea at all, but a real drainless lake. The sea should have access to the World Ocean, which the Caspian does not have, on the other hand, this salt lake has all the sea features, from the ebb and flow and ending with real storms, about which the sailors say: “Anyone who has survived a storm in the Caspian is not afraid of any oceanic storms ". And the oceanic bottom relief is convincing evidence that initially the Caspian, together with the Black and Azov Seas, belonged to a single ancient reservoir, that is, it was part of the World Ocean.

Where the Caspian Lake is now located, a depression was formed in the earth's crust several tens of thousands of years ago. Today it is filled with the waters of the Caspian. At the end of the 20th century, the water level in the Caspian Sea was 28 meters below the level of the World Ocean. About six thousand years ago, the waters of the Caspian gained independence, parting with the World Ocean. Another feature that distinguishes the Caspian from the sea is that the salinity of the water in it is almost three times lower than the salinity of the sea. This is because the rivers carry their fresh waters to the Caspian Sea. The Volga accounts for the largest contribution: it gives the sea-lake almost 80% of all waters. And it also connects the Caspian with the World Ocean through a system of canals. That is why this lake is still considered the sea!

In terms of its area and volume of water, the Caspian Sea-Lake has no equal on Earth. The volume of water in the Caspian Sea is 44% of the reserve of all lake waters of the planet! If we talk about the depth of reservoirs, their area and volume of water, the lake can compete with the Yellow, Baltic and Black Seas and surpasses the Aegean and Adriatic Seas in the same parameters.

Not every sea can boast of having so many names in its history as the Caspian: as many as seventy! Every traveler, every expedition to the Caspian Sea and the ancient peoples inhabiting its coast, gave him their names. The most famous names are: Dzhurdzhanskoe, Khvalynskoe, Shirvanskoe, Derbentskoe, Sarayskoe and finally, Khazarskoe. In Azerbaijan and Iran, the Caspian Sea is still called the Khazar Sea. And the sea got its modern name because of the tribes of the Caspian horse breeders, who for a long time inhabited the eastern parts of the Caucasus and the steppes of the Caspian territories.

The Caspian Sea is the hero of many legends and traditions in the epic of all peoples living on its shores. Legends, as a rule, tell about the love of the mighty and beautiful hero of the Caspian Sea for some of the beauties named Volga, Kura or Amu-Darya - the choice is huge, since about 130 large and small rivers flow into the sea, nine of which have mouths in the form deltas. Fantasy on the theme of love is about the same for everyone.

The sea water area is divided into three areas: North, Middle and South Caspian. The North Caspian is shallow. The deepest depth of the Middle Caspian in the area of ​​the Derbent depression is about 788 m. The South Caspian begins beyond the Absheron threshold, it is here that the sea is deepest: about 1025 m. For clarity, imagine three Eiffel towers, stacked on top of each other.

There are many secrets and mysteries associated with the Caspian Sea. In 1939, archaeologists-divers found a flooded ancient gostiny dvor (caravanserai) in the Baku bay. Many inscriptions have survived on the walls, indicating that the building was erected in 1234-1235. Perhaps these are the remains of the ancient city of Sabail. Ancient quarries have been discovered in the sea nearby. And in 1940, when laying a dam on the Absheron Peninsula, an ancient cemetery was discovered at the bottom of the sea. The burials date back to the 1st century BC. It can be assumed that the level of the Caspian in those days was about four meters lower than the present.

It is no coincidence that the inscription on the geographical map, compiled in 1320, reads: "The sea comes to one palm every year, and many good cities are already flooded."

Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuation have been carried out since 1837. The highest water level was recorded in 1882 (-25.2 m), the lowest - in 1977 (-29.0 m), since 1978 the water level has been rising and in 1995 reached -26.7 m, since 1996 Years again began to decline, and since 2001 - to rise again and reached the level of -26.3 m. The reasons for this "behavior" of the Caspian Sea - in climate change, as well as geological and anthropogenic factors.

Another mystery of the unique sea-lake remains the Caspian seal: scientists cannot answer the question of where the animal of northern latitudes came from in the Caspian. In total, 1809 species of various groups of animals live in the Caspian Sea. The Caspian Sea is also famous for its valuable fish species, in particular sturgeon. Their reserves account for up to 80% of the world's resources. The most valuable caviar is not black, as many are accustomed to believe, but white. The albino beluga caviar "Almas" has a color from light gray to white. The lighter, the more expensive: the cost of 100 grams is $ 2,000. This fish is caught in the Caspian Sea off the coast of Iran.

Many oil and gas fields are being developed in the Caspian Sea. The first oil well was drilled on the Absheron Peninsula near Baku back in 1820. In 1949, for the first time, they began to extract oil from the bottom of the Caspian Sea. Salt, limestone, stone, sand and clay are also mined on the coast of the Caspian Sea and the Caspian shelf.

The Caspian Sea washes the shores of five countries: Kazakhstan, Azerbaijan, Turkmenistan, Iran and Russia. For several years now, the Caspian Day has been celebrated in every country, reminding that the Caspian is not just a drinker and a breadwinner for the peoples inhabiting its shores, but a very fragile ecosystem.

By the way, in 1978, the World Maritime Day appeared in the calendar of world events, which belongs to the international days of the UN, designed to draw the attention of mankind to the problems of the hydraulic system. There is also an international day of the Black Sea: in 1996, representatives of Russia, Ukraine, Bulgaria, Romania, Turkey and Georgia signed a strategic action plan to save the Black Sea. In this series, the day of the Caspian Sea is also, rather, not a holiday, but a warning, a warning to people about how everything is interconnected in this world and how it is possible, mercilessly exploiting, to lose what is dear to everyone.

Marina Parenskaya

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

Geographical position

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

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

Peninsulas of the Caspian Sea

Major peninsulas of the Caspian Sea:

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

Islands of the Caspian Sea

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

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

Bays of the Caspian Sea

Large bays of the Caspian Sea:

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

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

Physiography

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

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

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

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

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

Climate- The climate of the Caspian Sea is continental in the northern part, temperate in the middle and subtropical in the southern part. In winter, the average monthly air temperature varies from -8 ... -10 in the northern part to + 8 ... + 10 in the southern part, in summer - from + 24 ... + 25 in the northern part to + 26 ... + 27 in the southern part. The maximum temperature of +44 degrees was recorded on the east coast. Average annual rainfall is 200 millimeters, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters off the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea is about 1000 millimeters per year, the most intense evaporation is in the area of ​​the Absheron Peninsula and in the eastern part of the South Caspian - up to 1400 millimeters per year. The average annual wind speed is 3-7 meters per second, northern winds prevail in the wind rose. In the autumn and winter months, the winds increase, the speed of the winds often reaches 35-40 meters per second. The most windy areas are the Apsheron Peninsula, the vicinity of Makhachkala and Derbent, where the highest wave with a height of 11 meters was also recorded.

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

Economic development of the Caspian Sea

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

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

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

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

Caspian Sea is inland and is located in an extensive mainland depression on the border of Europe and Asia. The Caspian Sea has no connection with the ocean, which formally allows us to call it a lake, but it has all the features of the sea, since in past geological eras it had connections with the ocean.
Today Russia has access only to the North Caspian and the Dagestan part of the western coast of the Middle Caspian. The waters of the Caspian Sea wash the shores of countries such as Azerbaijan, Iran, Turkmenistan, Kazakhstan.
The sea area is 386.4 thousand km2, the volume of water is 78 thousand m3.

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

Physically and geographically and by the nature of the underwater relief, the sea is divided into three parts: northern, middle and southern. The conditional border between the northern and middle parts runs along the line of the Chechen island - the Tyub-Karagan cape, between the middle and the south - along the line of the Zhiloy island - Kuuli cape.
The shelf of the Caspian Sea is, on average, limited to a depth of about 100 m. The continental slope, which begins below the edge of the shelf, ends in the middle part at a depth of 500–600 m, in the southern part, where it is very steep, at 700–750 m.

The northern part of the sea is shallow, its average depth is 5–6 m, maximum depths of 15–20 m are located on the border with the middle part of the sea. The bottom relief is complicated by the presence of banks, islands, grooves.
The middle part of the sea is a separate basin, the area of ​​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 Apsheron sill, which is a continuation of the Greater Caucasus. The depths above this underwater ridge do not exceed 180 m. The deepest part of the South Caspian depression with a maximum depth of 1025 m for the sea is located east of the Kura delta. Several underwater ridges up to 500 m high rise above the bottom of the basin.

The shores The Caspian Sea is diverse. In the northern part of the sea, they are quite indented. Here are the Kizlyarsky, Agrakhansky, Mangyshlaksky bays and many shallow bays. Notable peninsulas: Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak. Large islands in the northern part of the sea - Tyuleniy, Kulaly. In the deltas of the Volga and Ural rivers, the coastline is complicated by many islets and channels, which often change their position. Many small islands and banks are located 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 Absheron Peninsula is located. To the east of it, the islands and banks of the Absheron archipelago stand out, of which the largest is Zhiloy Island. The eastern coast of the Middle Caspian is more indented, here the Kazakh Gulf with Kenderli Bay and several capes stand out. The largest bay on this coast is Kara-Bogaz-Gol.

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

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

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

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

Climate. The Caspian Sea is located in temperate and subtropical climatic zones. Climatic conditions change in the meridional direction, since from north to south the sea stretches for almost 1200 km.
In the Caspian region, various systems of atmospheric circulation interact, however, during the year, the winds of the eastern points prevail (the influence of the Asian maximum). The position in rather low latitudes provides a positive balance of heat inflow, therefore the Caspian Sea serves as a source of heat and moisture for the passing air masses for most of the year. The average annual air temperature in the northern part of the sea is 8–10 ° С, in the middle - 11–14 ° С, in the southern part - 15–17 ° С. However, in the northernmost regions of the sea, the average January temperature is from –7 to –10 ° С, and the minimum during the invasions of the Arctic air is up to –30 ° С, which determines the formation of the ice cover. In summer, the entire region under consideration is dominated by rather high temperatures - 24–26 ° С. Thus, the North Caspian is subject to the sharpest temperature fluctuations.

The Caspian Sea is characterized by a very small amount of precipitation falling per year - only 180 mm, and most of it falls on the cold season of the year (from October to March). However, the North Caspian Sea differs in this respect from the rest of the basin: here the average annual precipitation is less (for the western part, only 137 mm), and the 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. Distinctive features of the Caspian Sea (large differences in depths in different parts of the sea, the nature of the bottom topography, isolation) have a certain impact on the formation of temperature conditions. In the shallow North Caspian, the entire water column can be regarded as homogeneous (the same applies to shallow bays located in other parts of the sea). In the Middle and South Caspian, surface and deep masses can be distinguished, separated by a transitional layer. In the North Caspian and in the surface layers of the Middle and South Caspian, the water temperature varies over a wide range. In winter, temperatures change from north to south from less than 2 to 10 ° С, the water temperature near the western coast is 1–2 ° С higher than that of the east, in the open sea the temperature is higher than at the coasts: by 2–3 ° С in the middle part and by 3–4 ° С in the southern part of the sea. In winter, the temperature distribution is more uniform with depth, which is facilitated by the winter vertical circulation. 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 point.

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

Salinity. Salinity values ​​are determined by such factors as river runoff, water dynamics, which mainly includes wind and gradient currents, the resulting water exchange between the western and eastern parts of the North Caspian and between the North and Middle Caspian, bottom topography, which determines the location of waters with different salinity, mainly along the isobaths, evaporation, providing a shortage of fresh water and the inflow of more saline ones. These factors collectively affect seasonal differences in salinity.
The North Caspian can be 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 Middle Caspian waters directly flow. In this case, the horizontal salinity gradients can reach 1 ‰ per 1 km.

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

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

Significant vertical 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 water arriving in summer from the seaside is 10–15 ° C higher than that of the bottom water.
In the deep-water 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 Apsheron sill area, where it is 1.6 ‰ in the surface layer and 2.1 ‰ at the 5 m horizon.

The decrease in salinity along the western coast of the South Caspian in the 0–20 m layer is caused by the Kura river runoff. The influence of the Kura runoff decreases with depth; at the 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, there is a strip of desalinated waters with a salinity of 10–12.5 ‰ coming from the North Caspian.

In addition, in the South Caspian, an increase in salinity occurs when saline waters are carried out from bays and bays on the eastern shelf under the influence of southeastern winds. Subsequently, these waters are transferred to the Middle Caspian.
In the deep layers of the Middle and South Caspian, salinity is about 13 ‰. In the central part of the Middle Caspian, such salinity is observed at horizons below 100 m, and in the deep-water part of the South Caspian, the upper boundary of waters with increased salinity drops to 250 m. It is obvious that in these parts of the sea, vertical mixing of waters is difficult.

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

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

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

On the dynamics of concentrations nutrients During the year, the Caspian Sea is influenced by such factors as seasonal fluctuations of biogenic runoff in the sea, seasonal ratio of production and destruction processes, the intensity of exchange between soil and water mass, ice conditions in winter in the North Caspian, processes of winter vertical circulation in deep-water areas seas.
In winter, a significant water area of ​​the North Caspian is covered with ice, but biochemical processes are actively developing in sub-ice water and in ice. The ice of the North Caspian, being a kind of accumulator of nutrients, transforms these substances entering the sea with river runoff and from the atmosphere.

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

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

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

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

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

More than 150 years on the shelf of the Caspian Sea oil.
Currently, large reserves of hydrocarbons are being developed on the Russian shelf, the resources of which on the Dagestan shelf are estimated at 425 million tons of oil equivalent (of which 132 million tons of oil and 78 billion cubic meters of gas), on the shelf of the North Caspian - 1 billion tons of oil ...
A total of about 2 billion tons of oil have already been produced in the Caspian Sea.
Losses of oil and products of its processing during extraction, transportation and use reach 2% of the total volume.
Main sources of income pollutants, including oil products, into the Caspian Sea - this is the outflow with river runoff, the discharge of untreated industrial and agricultural wastewater, municipal 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. Places of entry of pollutants with river runoff are 90% concentrated in the North Caspian, industrial effluents are mainly confined to the area of ​​the Absheron Peninsula, and increased oil pollution of the South Caspian is associated with oil production and oil exploration drilling, as well as with active volcanic activity (mud volcanism) in the zone of oil and gas structures.

From the territory of Russia, about 55 thousand tons of oil products are annually supplied to the North Caspian, including 35 thousand tons (65%) from the Volga River and 130 tons (2.5%) from the Terek and Sulak rivers.
Thickening of the film on the water surface up to 0.01 mm disrupts the processes of gas exchange, threatens the death of the hydrobiota. Toxic for fish is the concentration of oil products 0.01 mg / l, for phytoplankton - 0.1 mg / l.

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

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

Arctic species. The total number of the Arctic group is 14 species and subspecies, or only 1.2% of the entire fauna of the Caspian Sea (mysids, sea cockroach, white fish, Caspian salmon, Caspian seal, etc.). The basis of the Arctic fauna is made up of crustaceans (71.4%), which easily tolerate desalination and live at great depths in the Middle and South Caspian (from 200 to 700 m), since the lowest water temperatures are maintained here throughout the year (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 mithielastr mollusk penetrated here, later 2 types of shrimp (with mullet, when acclimatized), 2 types of mullet and flounder. Some Mediterranean species entered the Caspian after the opening of the Volga-Don Canal. Mediterranean species play an essential role in the food supply for fish in the Caspian Sea.

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

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

The Caspian Sea provides over 80% of the world's sturgeon catches, the bulk of which is in the North Caspian.
To increase catches of sturgeon, which sharply decreased during the years of falling sea level, a set of measures is being carried out. Among them is a complete ban on fishing for sturgeon in the sea and its regulation in rivers, an increase in the scale of factory sturgeon breeding.