The Caspian Sea is certainly the most curious inland water body on Earth. Whether it is a lake or a sea, we may never know—the dispute goes on for centuries. Surrounded by five countries, it plays a major role in their economy and generates a reasonable income from tourism.
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It is described as the world’s largest lake.
However, it is not a freshwater body, but due to 1,2% salinity puts it among the brackish water bodies.
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Along with the Black, Azov, and Aral seas, it is one of the largest saltwater bodies.
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It was formed 30 million years ago.
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It is a remnant of the Paratethys Sea of the Tethys Ocean, dating back to Mesozoic, and early Cenozoic Eras.
The Caspian Sea, along with the Black Sea, and the Aral Sea formed due to the evaporation of the Tethys Ocean.
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It covers an area of 386,400 square kilometers.
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The average depth of the Caspian Sea is about 210 meters.
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Its surface is located 28 meters below sea level.
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Whether it is a sea or a lake is a matter of political conflict.
Marking it as a lake would cause international law to lose all control of its use.
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In the north, it is encompassed by the Caspian Depression, one of the world’s lowest points.
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Its maximum depth is 1,025 meters, which places it in third place in terms of maximum depth, right after Baikal (1,637 m) and Tanganyika (1,435 m).
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Its name derives from the Kaspi, a tribe inhabiting the region in the 6th century B.C.
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It is surrounded by Kazakhstan, Russia, Turkmenistan, Iran, and Azerbaijan.
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The longest river in Europe, the Volga River, discharges into the Caspian Sea.
It provides over 80% of the inflowing water. Overall, 130 rivers flow into the Caspian Sea.
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There are 50 islands in the Caspian Sea.
The largest is the Ogurja Ada, which belongs to Turkmenistan.
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It has a diverse ecosystem.
Over 2,000 species live around the Caspian Sea, and approximately 400 of them are endemic to this unique area (such as Horsfield’s tortoise, Caspian gull, Caspian white fish, beluga sturgeon, Caspian turn, Caspian seal, or the spur-thighed tortoise).
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The beluga sturgeon is a critically endangered endemic species of fish.
It is the largest freshwater fish in the world, famous for its caviar. The vast majority of its caviar consumed worldwide comes from the Caspian Sea.
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The Caspian Sea has no outflow.
It loses water only through evaporation.
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It is rich in oil and gas reserves.
It is one of the world’s oldest oil-producing areas.
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Oil and gas production causes serious water and land pollution.
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The water level of the Caspian Sea varies, but recent measurements prove it systematically rises.
It flooded in 1977, and several times after that, causing widespread destruction. Since then, the water level has risen 2,2 meters. However, scientists have estimated that the water level drops by 7 cm each year, as a result of the global increase in temperature caused by climate change. If this trend continues, water loss may threaten the fauna and flora of the Caspian Sea.
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The Caspian Sea is a dumping site of over 1 million cubic meters of sewage annually.
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The Kara-Bogaz-Gol forms a lagoon on the Caspian Sea.
It covers an area of 18,000 square kilometers and is separated from the Caspian Sea by sand spits.
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Limestone, sand, clay, and salt are mined from the Caspian Sea.
