The largest lake in the world is the Caspian Sea. Why is the Caspian Sea so named and why is it called a lake

The Caspian Sea is a brief description of the endorheic salt lake of Eurasia and the largest lake on the planet is presented in this article. A message about the Caspian Sea will help you prepare for classes.

Caspian Sea: report

This water body is located at the geographical junction of Europe and Asia. The water level is 28 m below the level of the World Ocean. Over its long history, the Caspian Sea has “changed” more than 70 names. And it received its modern name from the ancient Caspian tribe, who were engaged in horse breeding and settled along the southwestern shore of the lake.

Salinity of the Caspian Sea not constant: near the mouth of the Volga River it is 0.05%, and in the southeast the figure increases to 13%. The area of ​​the water body today is about 371,000 km2, the maximum depth of the Caspian Sea is 1025 m.

Features of the Caspian Sea

Scientists have conditionally divided the lake-sea into 3 natural zones:

• Northern
• Average
• Southern

Each of them has a different depth and composition of water. For example, the smallest part is Northern. The full-flowing Volga River flows here, so the salinity here is the lowest. And the southern part is the deepest, and, accordingly, salty.

The Caspian Sea was formed more than 10 million years ago. It can be called part of the ancient Tethys superocean, which once lay between the African, Indian and Eurasian continental plates. Its long history is also evidenced by the nature of the bottom and geological coastal deposits. The length of the coastline is 6500 - 6700 km, and including the islands up to 7000 km.

The shores of the Caspian Sea are predominantly smooth and low-lying. The northern part of the coastline is indented by islands and channels of the Ural and Volga deltas. The shore is swampy and low, covered with thickets. The eastern coast is characterized by limestone coasts that are adjacent to deserts and semi-deserts. The west and east coasts have winding coastlines.

Where does the Caspian Sea flow?

Since the Caspian Sea is an endorheic body of water, it is logical that it does not flow anywhere. But 130 rivers flow into it. The largest of them are Terek, Volga, Emba, Ural, Kura, Atrek, Samur.

Climate of the Caspian Sea

In the northern part of the sea the climate is continental, in the middle part it is temperate and in the southern part it is subtropical. In winter, the average temperature ranges from – 8 … – 10 (northern part) to +8 … + 10 (southern part). Summer average temperatures range from +24 (northern part) to +27 (southern part). The maximum temperature recorded on the east coast was 44 degrees.

Animal and plant life

The fauna is diverse and includes 1809 species. The sea is home to 415 invertebrates and 101 species of fish. It contains most of the world's reserves of pike perch, sturgeon, roach, and carp. The Caspian Sea is home to carp, mullet, bream, sprat, perch, kutum, pike, as well as such a large mammal as the Caspian seal.

The flora is represented by 728 species. The sea is dominated by diatoms, brown algae, red algae, blue-green algae, chara algae, ruppium and zoster.

The importance of the Caspian Sea

On its territory there are many gas and oil reserves, the fields of which are at the development stage. Scientists have calculated that oil resources amount to 10 billion tons, and gas condensate - 20 billion tons. The first oil well was drilled in 1820 on the Absheron shelf. Limestone, sand, salt, stone, and clay are also mined on its shelf.

In addition, the Caspian Sea is popular among tourists. Modern resort areas are being created on its banks; mineral waters and mud contribute to the development of health complexes and sanatoriums. The most famous resorts are Amburan, Nardaran, Zagulba, Bilgakh.

Environmental problems of the Caspian Sea

Sea waters are polluted as a result of the extraction and transportation of gas and oil on the shelf. Pollutants also come from the rivers that flow into it. Poaching of sturgeon caviar has led to a decrease in the number of these fish.

We hope that the report on the Caspian Sea helped you prepare for the lesson. You can supplement your essay about the Caspian Sea using the comment form below.

The Caspian Lake is one of the most unique places on Earth. It keeps many secrets related to the history of the development of our planet.

Position on physical map

The Caspian Sea is an internal, drainless salt lake. The geographical location of the Caspian Lake is the continent of Eurasia at the junction of parts of the world (Europe and Asia).

The length of the lake shoreline ranges from 6500 km to 6700 km. Taking into account the islands, the length increases to 7000 km.

The coastal areas of the Caspian Lake are mostly low-lying. Their northern part is cut by the channels of the Volga and Ural. The river delta is rich in islands. The surface of the water in these areas is covered with thickets. Large areas of land are swampy.

The eastern coast of the Caspian Sea adjoins the On the shores of the lake there are significant deposits of limestone. The western and part of the eastern coasts are characterized by a winding coastline.

The Caspian Lake is represented on the map by its considerable size. The entire territory adjacent to it was called the Caspian region.

Some characteristics

The Caspian Lake has no equal on Earth in terms of its area and volume of water. It stretches from north to south for 1049 kilometers, and its longest length from west to east is 435 kilometers.

If we take into account the depth of the reservoirs, their area and volume of water, then the lake is comparable to the Yellow, Baltic and Black Seas. According to the same parameters, the Caspian Sea surpasses the Tyrrhenian, Aegean, Adriatic and other seas.

The volume of water available in the Caspian Lake is 44% of the supply of all lake waters on the planet.

Lake or sea?

Why is the Caspian Lake called a sea? Was it really the impressive size of the reservoir that became the reason for assigning such a “status”? More precisely, this became one of these reasons.

Others include the huge mass of water in the lake, the presence of large waves during stormy winds. All this is typical for real seas. It becomes clear why the Caspian Lake is called a sea.

But one of the main conditions that must exist in order for geographers to classify a body of water as a sea is not mentioned here. We are talking about a direct connection between the lake and the World Ocean. It is precisely this condition that the Caspian Sea does not meet.

Where the Caspian Lake is 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 Sea. According to scientists, at the end of the 20th century, the water level in the Caspian Sea was 28 meters below the level of the World Ocean. The direct connection between the waters of the lake and the ocean ceased to exist approximately 6 thousand years ago. The conclusion from the above is that the Caspian Sea is a lake.

There is one more feature that distinguishes the Caspian Sea from the sea - the salinity of its water is almost 3 times lower than the salinity of the World Ocean. The explanation for this is that about 130 large and small rivers carry fresh water to the Caspian Sea. The Volga makes the most significant contribution to this work - it “gives” up to 80% of all water to the lake.

The river played another important role in the life of the Caspian Sea. It is she who will help find the answer to the question of why the Caspian Lake is called a sea. Now that man has built many canals, it has become a fact that the Volga connects the lake with the World Ocean.

History of the lake

The modern appearance and geographical position of the Caspian Lake are determined by continuous processes occurring on the surface of the Earth and in its depths. There were times when the Caspian was connected to the Sea of ​​Azov, and through it to the Mediterranean and Black Sea. That is, tens of thousands of years ago the Caspian Lake was part of the World Ocean.

As a result of processes associated with the rise and fall of the earth's crust, mountains appeared that are located on the site of the modern Caucasus. They isolated a body of water that was part of a huge ancient ocean. Tens of thousands of years passed before the basins of the Black and Caspian Seas separated. But for a long time the connection between their waters was carried out through the strait, which was on the site of the Kuma-Manych depression.

Periodically, the narrow strait was either dried up or filled with water again. This happened due to fluctuations in the level of the World Ocean and changes in the appearance of the land.

In a word, the origin of the Caspian Lake is closely connected with the general history of the formation of the Earth's surface.

The lake received its modern name because of the Caspian tribes that inhabited the eastern parts of the Caucasus and the steppe zones of the Caspian territories. Throughout the history of its existence, the lake has had 70 different names.

Territorial division of the lake-sea

The depth of the Caspian Lake is very different in different places. Based on this, the entire water area of ​​the lake-sea was conditionally divided into three parts: the Northern, Middle and Southern Caspian.

Shallow water is the northern part of the lake. The average depth of these places is 4.4 meters. The highest level is 27 meters. And on 20% of the entire area of ​​the Northern Caspian the depth is only about a meter. It is clear that this part of the lake is of little use for navigation.

The Middle Caspian has the greatest depth of 788 meters. The deep-water part is occupied by lakes. The average depth here is 345 meters, and the greatest is 1026 meters.

Seasonal changes at sea

Due to the large extent of the reservoir from north to south, the climatic conditions on the coast of the lake are not the same. Seasonal changes in the areas adjacent to the reservoir also depend on this.

In winter, on the southern coast of the lake in Iran, the water temperature does not drop below 13 degrees. During the same period, in the northern part of the lake off the coast of Russia, the water temperature does not exceed 0 degrees. The Northern Caspian is covered with ice for 2-3 months of the year.

In summer, almost everywhere the Caspian Lake warms up to 25-30 degrees. Warm water, excellent sandy beaches, and sunny weather create excellent conditions for people to relax.

Caspian Sea on the political map of the world

There are five states on the shores of the Caspian Lake - Russia, Iran, Azerbaijan, Kazakhstan and Turkmenistan.

The western regions of the Northern and Middle Caspian Sea belong to the territory of Russia. Iran is located on the southern shores of the sea, it owns 15% of the entire coastline. The eastern coastline is shared by Kazakhstan and Turkmenistan. Azerbaijan is located in the southwestern territories of the Caspian region.

The issue of dividing the lake’s waters between the Caspian states has been the most pressing for many years. The heads of five states are trying to find a solution that would satisfy everyone's needs and requirements.

Natural resources of the lake

Since ancient times, the Caspian Sea has served as a water transport route for local residents.

The lake is famous for valuable fish species, in particular sturgeon. Their reserves account for up to 80% of the world's resources. The issue of preserving the sturgeon population is of international importance; it is being resolved at the level of the government of the Caspian states.

The Caspian seal is another mystery of the unique sea-lake. Scientists have still not fully unraveled the mystery of the appearance of this animal in the waters of the Caspian Sea, as well as other species of animals of northern latitudes.

In total, the Caspian Sea is home to 1,809 species of different groups of animals. There are 728 species of plants. Most of them are “indigenous inhabitants” of the lake. But there is a small group of plants that were brought here intentionally by humans.

Of the mineral resources, the main wealth of the Caspian Sea is oil and gas. Some information sources compare the oil reserves of the Caspian Lake fields with those of Kuwait. Industrial sea mining of black gold has been carried out on the lake since the end of the 19th century. The first well appeared on the Absheron shelf in 1820.

Today, governments unanimously believe that the region cannot be viewed only as a source of oil and gas, while leaving the ecology of the Caspian Sea without attention.

In addition to oil fields, in the Caspian region there are deposits of salt, stone, limestone, clay and sand. Their production also could not but affect the ecological situation of the region.

Sea level fluctuations

The water level in the Caspian Lake is not constant. This is evidenced by evidence dating back to the 4th century BC. The ancient Greeks, who explored the sea, discovered a large bay at the confluence of the Volga. The existence of a shallow strait between the Caspian and the Sea of ​​Azov was also discovered by them.

There are other data on the water level in the Caspian Lake. The facts suggest that the level was much lower than what exists now. The proof is provided by ancient architectural structures discovered on the seabed. The buildings date back to the 7th-13th centuries. Now the depth of their flooding ranges from 2 to 7 meters.

In 1930, the water level in the lake began to decline catastrophically. The process continued for almost fifty years. This caused great concern among people, since all economic activity in the Caspian region is adapted to the previously established water level.

From 1978 the level began to rise again. Today he has become more than 2 meters higher. This is also an undesirable phenomenon for people living on the coast of the lake-sea.

The main reason affecting fluctuations in the lake is climate change. This entails an increase in the volume of river water entering the Caspian Sea, the amount of precipitation, and a decrease in the intensity of water evaporation.

However, it cannot be said that this is the only opinion that explains the fluctuation in water level in the Caspian Lake. There are others, no less plausible.

Human activities and environmental issues

The area of ​​the Caspian Lake's drainage basin is 10 times larger than the surface of the reservoir itself. Therefore, all changes occurring in such a vast territory in one way or another affect the ecology of the Caspian Sea.

Human activity plays an important role in changing the environmental situation in the Caspian Lake region. For example, pollution of a reservoir with harmful and dangerous substances occurs along with the influx of fresh water. This is directly related to industrial production, mining and other human activities in the watershed.

The state of the environment of the Caspian Sea and adjacent territories is of general concern to the governments of the countries located here. Therefore, the discussion of measures aimed at preserving the unique lake, its flora and fauna has become traditional.

Each state has an understanding that only through joint efforts can the ecology of the Caspian Sea be improved.

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 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 shores 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 events, the northern coast of the Caspian Sea shifted to the Samara Luka on the Volga, and perhaps 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. During extreme regressions, the southern coast of 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, in the estuary coastal zones of 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 latitudinal 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, water salinity 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), and the use of 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 also used 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 of the Caspian Sea create 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 activities 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 coast.

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 the international legal status of the Caspian Sea, the 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 Moscow State University, etc. took an active part in the study of the Caspian Sea.

The Caspian Sea is one of the largest salty bodies of water on Earth, located at the junction of Europe and Asia. Its total area is about 370 thousand square meters. km. The reservoir receives more than 100 water streams. The largest rivers flowing into the Volga, Ural, Emba, Terek, Sulak, Samur, Kura, Atrek, Sefidrud.

The Volga River - the pearl of Russia

The Volga is a river flowing on the territory of the Russian Federation, partially crossing Kazakhstan. It belongs to the category of the largest and longest rivers on Earth. The total length of the Volga is more than 3,500 km. The river originates in the village of Volgoverkhovye, Tver Region, located on After that, it continues its movement through the territory of the Russian Federation.

It flows into the Caspian Sea, but does not have direct access to the World Ocean, so it is classified as internal drainage. The watercourse receives about 200 tributaries and has more than 150 thousand outlets. Today, reservoirs have been built on the river to regulate flow, which has sharply reduced fluctuations in water levels.

The river's fisheries are varied. In the Volga region, melon growing predominates: the fields are occupied by grain and industrial crops; table salt is extracted. Oil and gas deposits have been discovered in the Urals region. The Volga is the largest river flowing into the Caspian Sea, so it is of great importance for Russia. The main transport structure that allows you to cross this stream is the longest in Russia.

Ural - river in Eastern Europe

The Ural, like the Volga River, flows on the territory of two states - Kazakhstan and the Russian Federation. Historical name - Yaik. It originates in Bashkortostan at the top of the Uraltau ridge. The Ural River flows into the Caspian Sea. Its pool is the sixth largest in the Russian Federation, and its area is more than 230 square meters. km. Interesting fact: the Ural River, contrary to popular belief, is an inland European river, and only its upper course in Russia belongs to Asia.

The mouth of the watercourse gradually becomes shallow. At this point the river divides into several branches. This feature is characteristic along the entire length of the channel. During floods, you can observe how the Ural overflows its banks, in principle, like many other Russian rivers flowing into the Caspian Sea. This is especially observed in places with a gently sloping coastline. Flooding occurs at a distance of up to 7 meters from the riverbed.

Emba - river of Kazakhstan

Emba is a river flowing in the territory of the Republic of Kazakhstan. The name comes from the Turkmen language, literally translated as “valley of food”. The river basin has an area of ​​40 thousand square meters. km. The river begins its journey in the Mugodzhary mountains and, as it flows, it gets lost among the swamps. When asking which rivers flow into the Caspian Sea, we can say that in high-flow years the Emba reaches its basin.

Along the river's coastline, natural resources such as oil and gas are being extracted. The issue of passing the border between Europe and Asia along the Emba watercourse, as in the case of the river. Ural, an open topic even today. The reason for this is a natural factor: the mountains of the Ural Range, which are the main landmark for drawing boundaries, disappear, forming a homogeneous terrain.

Terek - mountain water stream

Terek is a river of the North Caucasus. The name is literally translated from Turkic as “poplar”. The Terek flows from the glacier of Mount Zilga-Khokh, located in the Trusovsky Gorge of the Caucasus Range. passes through the lands of many states: North Ossetia, Georgia, Stavropol Territory, Kabardino-Balkaria, Dagestan and the Chechen Republic. It flows into the Caspian Sea and Arkhangelsk Bay. The length of the river is just over 600 km, the basin area is about 43 thousand square meters. km. An interesting fact is that every 60-70 years the flow forms a new transit branch, while the old one loses its strength and disappears.

The Terek, like other rivers flowing into the Caspian Sea, is widely used to satisfy human economic needs: it is used to irrigate the arid areas of the adjacent lowlands. There are also several hydroelectric power stations located on the water stream, the total average annual production of which is more than 200 million kWh. New additional stations are planned to be launched in the near future.

Sulak - water stream of Dagestan

Sulak is a river connecting the Avar Koisu and Andean Koisu streams. It flows through the territory of Dagestan. It begins in the Main Sulak Canyon and ends its journey in the waters of the Caspian Sea. The main purpose of the river is to supply water to two cities of Dagestan - Makhachkala and Kaspiysk. Also, several hydroelectric power stations are already located on the river, and new ones are planned to be launched to increase the generated power.

Samur - the pearl of Southern Dagestan

Samur is the second largest river in Dagestan. The name is literally translated from Indo-Aryan as “abundance of water.” It originates at the foot of Mount Guton; It flows into the waters of the Caspian Sea through two branches - Samur and Small Samur. The total length of the river is just over 200 km.

All rivers flowing into the Caspian Sea are of great importance for the territories through which they flow. Samur is no exception. The main purpose of using the river is to irrigate land and provide residents of nearby cities with drinking water. It is because of this that the waterworks and a number of the Samur-Divichi canal were built.

At the beginning of the twentieth century (2010), Russia and Azerbaijan signed an interstate agreement requiring both parties to rationally use the resources of the Samur River. The same agreement introduced territorial changes between these countries. The border of the two states has been moved to the middle of the hydroelectric complex.

Kura - the largest river in Transcaucasia

When wondering which rivers flow into the Caspian Sea, I would like to describe the Kuru stream. It flows on the land of three states at once: Turkey, Georgia, Azerbaijan. The length of the stream is more than 1000 km, the total area of ​​the basin is about 200 thousand square meters. km. Part of the basin is located on the territory of Armenia and Iran. The source of the river is in the Turkish province of Kars, flowing into the waters of the Caspian Sea. The path of the river is thorny, laid among hollows and gorges, for which it received its name, which translated from the Mingrelian language means “gnaw”, that is, the Kura is a river that “gnaws” itself among the mountains.

There are many cities on it, such as Borjomi, Tbilisi, Mtskheta and others. It plays an important role in meeting the economic needs of the residents of these cities: fishing is carried out, hydroelectric power stations are located, and the Mingachevir reservoir created on the river is one of the main fresh water reserves for Azerbaijan. Unfortunately, the ecological state of the stream leaves much to be desired: the level of harmful substances is several times higher than the permissible limits.

Features of the Atrek River

Atrek is a river located on the territory of Iran and Turkmenistan. It originates in the Turkmen-Kharasan mountains. Due to active use for economic needs for irrigation, the river has become shallow. For this reason, it reaches the Caspian Sea only during flood periods.

Sefidrud - high-water river of the Caspian Sea

Sefidrud is a major river of the Iranian state. Initially it was formed by the confluence of two water streams - Kyzyluzen and Shahrud. Now it flows out of the Shabanau reservoir and flows into the depths of the Caspian Sea. The total length of the river is more than 700 km. The creation of a reservoir became a necessity. It made it possible to minimize the risk of flooding, thereby protecting the cities located in the river delta. The waters are used to irrigate lands with a total area of ​​more than 200 thousand hectares of land.

As can be seen from the presented material, the Earth's water resources are in unsatisfactory condition. The rivers flowing into the Caspian Sea are actively used by people to satisfy their needs. And this has a detrimental effect on their condition: watercourses are depleted and polluted. That is why scientists around the world are sounding the alarm and conducting active propaganda, calling for saving and conserving water on Earth.

The Caspian Sea is located at the junction of two parts of the 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 Zhilaya 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; Xihai 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. The largest 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 major Azerbaijani Caspian cities are Sumgait, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the southeast of the Absheron Peninsula, there is an oil workers’ settlement called Neftyanye Kamni, whose structures are located on artificial islands, overpasses and technological sites.

Large Russian cities - the capital of Dagestan, Makhachkala, and the southernmost city of Russia, Derbent - are 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 the northern coast of the Caspian Sea.

On the eastern shore of 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 off the west coast is 1 - 2 °C higher than that on 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 amount of heat is spent on melting 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 northwest winds prevailing in the summer season. 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 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 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, the average monthly temperature of the Caspian Sea varies from −8 −10 in the northern part to +8 - +10 in the southern part, in summer - from +24 - +25 in the northern part to +26 - +27 in the southern part. The 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.

On the territory of the Caspian Sea, winds often blow, their average annual speed is 3-7 meters per second, and northern winds predominate in the wind rose. In the autumn and winter months, winds become stronger, with wind speeds often reaching 35-40 meters per second. The most windy areas are the Absheron Peninsula and the environs of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.

Water circulation in the Caspian Sea is related to runoff and winds. Since most of the drainage occurs in 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.