The Caspian lake. Why is the Caspian Sea called the sea?

The Caspian lake is one of the most unique places on Earth. It stores many secrets connected with the history of the development of our planet.

Position on the physical map

The Caspian is an internal, drainless salt lake. The geographic 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 shore line of the lake ranges from 6,500 km to 6,700 km. Taking into account the islands, the extension is increased to 7000 km.

The coastal areas of the Caspian Lake are mostly low-lying. The northern part of them is cut by the channels of the Volga and the Urals. The delta of the rivers is rich in islands. The surface of the water in these areas is covered with thickets. Bogged large areas of land.

The eastern coast of the Caspian is adjacent to deserts and semi-deserts. On the shores of the lake there are significant deposits of limestone. For the western and part of the east coast is characterized by a winding line of the shore.

The Caspian lake on the map is represented by considerable sizes. All the adjoining territory was called the Caspian Sea.

Some characteristics

The Caspian lake has no equal in its area and water volume in it on the Earth. It stretches from north to south for 1049 kilometers, and its largest length from west to east is 435 kilometers.

If you take into account the depth of water bodies, their area and the volume of water, the lake is commensurate with the Yellow, Baltic and Black Seas. By the same parameters, the Caspian is superior to the Tyrrhenian, Aegean, Adriatic and other seas.

The volume of water available in the Caspian lake makes up 44% of the reserve of all the lake water of the planet.

The lake or the sea?

Why is the Caspian Sea called the sea? Is it just the impressive size of the reservoir that led to the appropriation of such a "status"? More precisely, it became one of such reasons.

Others include a huge mass of water in the lake, the presence of tides and waves , a large wave during the storm winds. All this is characteristic of real seas. It becomes clear why the Caspian is called the sea.

But here one of the main conditions that should not exist is one that must necessarily exist so that geographers can rank the pond to the sea. This refers to the direct connection of the lake to the world's oceans. It is this condition that the Caspian does not match.

Where the Caspian Lake is located, tens of thousands of years ago a deepening in the earth's crust formed. 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 of the waters of the lake and the ocean ceased to exist approximately 6 millennia ago. The conclusion from the above is that the Caspian Sea is a lake.

There is one more feature that distinguishes the Caspian from the sea - the salinity of the water in it 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. Volga brings to this work the most significant contribution - up to 80% of all water "gives" the lake it is.

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

History of the Lake

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

As a result of the processes associated with raising and lowering the earth's crust, mountains appeared on the site of the present-day Caucasus. They isolated a pond that was part of a huge ancient ocean. Tens of thousands of years passed before the basins of the Black and Caspian seas split. But for a long time the connection between their waters was realized through the strait, which was in place of the Kumo-Manych depression.

Periodically the narrow strait was then drained, then again filled with water. This was 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 inhabiting the eastern parts of the Caucasus and the steppe zones of the Caspian territories. For all history of existence the lake had 70 different names.

Territorial division of lake-sea

The depth of the Caspian Lake in its different places is very different. Proceeding from this, the entire water area of the lake-sea was conditionally divided into three parts: the Northern Caspian, the Middle and the South.

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

The average Caspian has the greatest depth of 788 meters. The deep-water part occupies the southern water area of the lake. The average depth here is 345 meters, and the largest - 1,026 meters.

Seasonal changes at sea

Because of the great length of the reservoir from north to south, the climatic conditions on the shore of the lake are not the same. Seasonal changes also depend on this in the territories adjacent to the reservoir.

In winter, the temperature of the water does not drop below 13 degrees on the southern coast of the lake in Iran. In the same period in the northern part of the lake off the coast of Russia, water has a temperature of no higher than 0 degrees. The Northern Caspian is ice-bound for 2-3 months a year.

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

The Caspian on the political map of the world

On the shores of the Caspian lake are five states - Russia, Iran, Azerbaijan, Kazakhstan and Turkmenistan.

The territory of Russia belongs to the western regions of the Northern and Middle Caspian. Iran is located on the southern shores of the sea, it owns 15% of the entire length of the coastline. The eastern coastline is shared by Kazakhstan and Turkmenistan. In the south-western territories of the Caspian region, Azerbaijan is located.

The issue of dividing the lake water between the Caspian states has been the most acute for many years. The heads of the five states are trying to find a solution that would satisfy the demands and demands of everyone.

Natural treasures of the lake

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

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

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

In total, 1809 species of various groups of animals inhabit the Caspian Sea. There are 728 species of plants. Most of them are the "aboriginals" of the lake. But there is a small group of plants that were brought here by the person intentionally.

Of the minerals, the main wealth of the Caspian is oil and gas. Some information sources compare the oil reserves of the Caspian Sea deposits with Kuwait. Industrial marine extraction of black gold has been conducted on the lake since the end of the XIX century. The first well appeared on the Absheron shelf in 1820.

Today, the governments of the Caspian states unanimously believe that it is impossible to consider the region only as a source of oil and gas, while neglecting the ecology of the Caspian.

In addition to oil deposits, there are deposits of salt, stone, limestone, clay and sand on the territory of the Caspian Sea. Their extraction could not but affect the ecological situation in the region.

Sea-level fluctuations

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

There are other data on the water level in the Caspian Lake. The facts indicate that the level was much lower than the current level. Evidence is the ancient architectural structures found on the seabed. Buildings belong to the VII-XIII centuries. Now the depth of their flooding is from 2 to 7 meters.

In 1930, the water level in the lake began to decline catastrophically. The process lasted for almost fifty years. This caused great concern among people, since all the economic activities of the Caspian Sea are adapted to the previously established water level.

Since 1978, the level has started to rise again. Today, it has grown by more than 2 meters. This is also an undesirable phenomenon for people living on the shores of the lake-sea.

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

However, it can not be said that this is the only opinion explaining the fluctuation of the water level in the Caspian Lake. There are other, no less plausible.

Human activities and environmental problems

The catchment area of the Caspian lake is 10 times the surface area of the water body itself. Therefore, all the changes that take place on such a huge territory in one way or another affect the ecology of the Caspian Sea.

Human activity plays an important role in changing the ecological situation in the region of the Caspian Lake. For example, the contamination of the reservoir by harmful and dangerous substances occurs together with the influx of fresh water. This is directly related to industrial production, mining of mineral resources and other economic activities of a person in the catchment area.

The state of the environment of the Caspian Sea and its surrounding areas 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 by joint efforts can the ecology of the Caspian be improved.