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Caspian Sea

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The Caspian Sea is the largest inland body of water on Earth.

Caspian Sea from orbit
Caspian Sea from orbit

While it is often called a sea, it is technically an endorheic basin. An endorheic basin is a closed system where water flows in but never flows out to the ocean. Instead, water only leaves the basin through evaporation. This unique setup means its water levels change independently of the world's oceans.

Paratethys Megalake Infographic 23X 2 EN
Paratethys Megalake Infographic 23X 2 EN

It covers a surface area of approximately 371,000 square kilometers. This is roughly the same size as the country of Japan.

Geographically, the Caspian Sea sits at a crossroads between Europe and Asia.

Afro-Eurasia location map with borders
Afro-Eurasia location map with borders

It is located east of the Caucasus and west of the Central Asian steppes. To the north, it is bordered by Russia and Kazakhstan. To the west sits Azerbaijan, while Turkmenistan lies to the southeast. The southern coast is bounded by Iran. The sea is quite large, stretching 1,200 kilometers from north to south. Its surface sits about 27 meters below global sea level.

The water in the Caspian Sea is brackish, meaning it is slightly salty. Its salinity is about 1.2%, which is only one third of the salinity found in average seawater.

Caspian Sea
Caspian Sea

Most of this water comes from over 130 different rivers. The Volga River is the most important source. It is the longest river in Europe and provides about 80% of the sea's total inflow. Other notable rivers include the Ural and the Kura. Because the system is closed, the water level relies heavily on rainfall in the Volga's catchment basin.

The sea is divided into three distinct physical regions. The Northern Caspian is a very shallow shelf. It holds less than 1% of the total water volume and averages only 5 to 6 meters in depth. The Middle Caspian is deeper, with an average depth of 190 meters. The Southern Caspian is the deepest zone. Here, the seabed reaches depths of over 1,023 meters.

Caspian Sea
Caspian Sea

This makes the southern seabed the third-lowest natural non-oceanic depression on Earth. These different depths create unique zones for temperature, salt levels, and ecology.

The history of the Caspian Sea is millions of years old. Scientists believe it is a remnant of the ancient Paratethys Sea.

Paratethys Megalake Infographic 23X 2 EN
Paratethys Megalake Infographic 23X 2 EN

About 5.5 million years ago, tectonic uplift and falling sea levels turned it into a landlocked basin. Its name comes from the ancient Caspi people. They lived in the region known as Transcaucasia.

Caspian sea Ibn Hawqal
Caspian sea Ibn Hawqal

Over time, different cultures have given it many names. In the past, Arabic speakers called it the "sea of the Khazars." This refers to the Khazar Khaganate, a large empire that existed north of the sea between the 7th and 10th centuries.

Today, the Caspian Sea is a vital center for several major industries. It is famous for its oil and gas resources.

Caspian region oil and natural gas infrastructure
Caspian region oil and natural gas infrastructure

You can see large structures used for extraction on the water.

Jack-up-rig-in-the-caspian-sea
Jack-up-rig-in-the-caspian-sea

It is also well known for its caviar industry. However, these industries bring environmental challenges. Pollution from oil refining and untreated sewage from the Volga River harms the ecosystem. Additionally, the construction of dams on feeder rivers can change the water flow.

Looking toward the future, the Caspian Sea faces significant risks. Scientists predict that the water level may decrease by 9 to 18 meters during the 21st century. This decline is linked to global warming and desertification. Such a drop in water could lead to an ecocide, which is a massive loss of life in an ecosystem. Maintaining the balance of this massive, ancient body of water remains a major global concern.

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🖼️ Images & Media (33)
File:Flag of Azerbaijan.svg
Flag of Azerbaijan.svg
File:Flag of the Ottoman Empire (1844–1922).svg
Flag of the Ottoman Empire (1844–1922).svg
File:Flag of the Soviet Union.svg
Flag of the Soviet Union.svg
File:State flag of Iran (1964–1980).svg
State flag of Iran (1964–1980).svg
File:Flag of Kazakhstan.svg
Flag of Kazakhstan.svg
File:Flag of Turkmenistan.svg
Flag of Turkmenistan.svg
File:Flag of Iran.svg
Flag of Iran.svg
File:Afro-Eurasia location map with borders.svg
Afro-Eurasia location map with borders.svg
File:Symbol template class pink.svg
Symbol template class pink.svg
File:Red pog.svg
Red pog.svg
File:West Asia non political with water system.jpg
West Asia non political with water system.jpg
File:Paratethys Megalake Infographic 23X 2 EN.jpg
Paratethys Megalake Infographic 23X 2 EN.jpg

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