The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the world’s largest lake or a full-fledged sea.
It is in an endorheic basin (it has no outflows) located between Europe and Asia.
It is bordered on the northeast by Kazakhstan, on the southeast by Turkmenistan, on the south by Iran, on the southwest by Azerbaijan, and on the northwest by Russia.
The elongated sea sprawls for 1,030 kilometers (640 miles) from north to south, although its average width is only 320 kilometers (200 miles); max. width is 435 kilometers (270 miles).
The sea has a surface area of 371,000 square kilometers (143,200 square miles) and its surface lies 28 meters (92 feet) below sea level.
The maximum depth is 1,025 meters (3,360 feet) and average depth 211 meters (690 feet) below the sea’s surface.
The water volume of the Caspian Sea is about 78,200 cubic kilometers (18,800 cubic miles).
Caspian Sea forms 40 to 44% of the total lake waters of the world.
It has a salinity of approximately 1.2% (12 g/l), about a third of the salinity of most seawater.
The drainage basin of the sea covers some 3,625,000 square kilometers (1,400,000 square miles).
The Caspian receives the Volga (which supplies about 80% of its inflow), Ural, Emba, Kura, and Terek rivers, but has no outlet; There are about 130 rivers which drain water into the Caspian Sea.
It has a large embayment on the shore of Turkmenistan, namely Kara Bogaz Gol.
There are many islands scattered throughout the Caspian Sea, most of which are uninhabited by humans.
The longest island in the Caspian Sea is Ogurja Ada which is 37 kilometers (23 miles) long. Its maximum width is 3 kilometers (1.86 miles).
Conversely, the climate to the southwest and south are generally warm with uneven elevation due to a mix of highlands and mountain ranges; the drastic changes in climate alongside the Caspian have led to a great deal of biodiversity in the region.
The Caucasus Mountains rise from the southwestern shore, and the Elburz Mountains parallel the southern coast.
The Caspian Sea, like the Aral Sea, Black Sea, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level.
Approximately 850 animal species and more than 500 plant species are represented in the Caspian. This number of species is relatively low for a body of water of this size. Many species are unique to the Caspian.
There are 115 species of fish found in the lake.
Sturgeons, including the beluga sturgeon, the largest freshwater fish in the world, inhabit the Caspian Sea in great numbers and yield roe (eggs) that are processed into caviar. In recent years, overfishing has threatened the sturgeon population to the point that environmentalists advocate banning sturgeon fishing completely until the population recovers.
Other fish speaces include Caspian roach, Caspian marine shad, Caspian bream, and the Caspian salmon; there is also several species of mollusks; and a range of other marine organisms including sponges.
Reptiles native to the sea include spur-thighed tortoise and Horsfield’s tortoise. The Caspian turtle, although found in neighbouring areas, is a wholly freshwater species.
Several species of animals are named after the region, like the Caspian gull, the Caspian tern, and the Caspian seal, which is the only aquatic mammal that can be found here and is endemic to the lake.
As the only coast in Azerbaijan, Kazakhstan and Turkmenistan, the Caspian Sea is a popular destination for domestic tourists.
Baku, the capital of Azerbaijan is the largest city by the Caspian Sea.
In Iran, the Caspian coast offers sandy beaches, lush vegetation, and spectacular natural scenery which provide a refreshing contrast to city life and the dry interior
The word “Caspian” is derived from Caspi, an ancient tribe that lived in the southwestern part of the sea, in Transcaucasia.
The lake was and still is known under many different names. The Greeks and Persians used to call the lake the the Hyrcanian Ocean. In Persian antiquity but also in modern Iran, the Caspian Sea is known as the Mazandaran Sea. Indians used to call it Kashyap Sagar, which in Turkey is known under the name of Khazar Sea.
The Caspian Sea region is one of the oldest oil-producing areas in the world and is an increasingly important source of global energy production. The area has significant oil and natural gas reserves from both offshore deposits in the Caspian Sea itself and onshore fields in the region.
The level of the Caspian has fallen and risen, often rapidly, many times over the centuries.
The last short-term sea-level cycle started with a sea-level fall of 3 meters (9.84 feet) from 1929 to 1977, followed by a rise of 3 meters (9.84 feet) from 1977 until 1995. Since then smaller oscillations have taken place. These changes have caused major environmental problems.
A number of fossils of human ancestors like Homo erectus have been recovered from the region around the Caspian Sea.