​

The Caspian Sea accounts for 40 to 44 percent of the total lacustrine waters of the world.  The coastlines of the Caspian are shared by Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan.

​

The Caspian Sea can be divided into five different regions based on their physical and geographical characteristics:

Northern Caspian Sea: This region is located in the northern part of the Caspian Sea and is characterized by shallow waters and sandy beaches. It is also the location of several large islands, including Ogurja Ada Island and Tyuleniy Island.

 

Southern Caspian Sea: This region is located in the southern part of the Caspian Sea and is characterized by deep waters and rocky coastlines. The largest island in this region is Ashuradeh Island, which is located off the coast of Iran.

 

Western Caspian Sea: This region is located in the western part of the Caspian Sea and is characterized by a rugged coastline and deep waters. It is also home to several large rivers, including the Volga and the Ural.

Eastern Caspian Sea: This region is located in the eastern part of the Caspian Sea and is characterized by shallow waters and extensive wetlands. It is also the location of several large cities, including Turkmenbashi and Aktau.

 

Central Caspian Sea: This region is located in the central part of the Caspian Sea and is characterized by deep waters and a relatively flat seabed. It is also the location of several large oil and gas fields, which have been the subject of exploration and development by the surrounding countries.

 

 

 

Hazards in and around the Caspian

 

 

​

​

 

​

 

 

  

​

Caspian is divided into three distinct physical regions: the Northern, Middle, and Southern Caspian.[15] The Northern–Middle boundary is the Mangyshlak Threshold, which runs through Chechen Island and Cape Tiub-Karagan. The Middle–Southern boundary is the Apsheron Threshold, a sill of tectonic origin between the Eurasian continent and an oceanic remnant,[16] that runs through Zhiloi Island and Cape Kuuli.[17] The Garabogazköl Bay is the saline eastern inlet of the Caspian, which is part of Turkmenistan and at times has been a lake in its own right due to the isthmus that cuts it off from the Caspian.

 

Differences between the three regions are dramatic. The Northern Caspian only includes the Caspian shelf,[18] and is very shallow; it accounts for less than 1% of the total water volume with an average depth of only 5–6 metres (16–20 ft). The sea noticeably drops off towards the Middle Caspian, where the average depth is 190 metres (620 ft).[17] The Southern Caspian is the deepest, with oceanic depths of over 1,000 metres (3,300 ft), greatly exceeding the depth of other regional seas, such as the Persian Gulf. The Middle and Southern Caspian account for 33% and 66% of the total water volume, respectively.[15]

The northern portion of the Caspian Sea typically freezes in the winter, and in the coldest winters ice forms in the south as well.[19]

 

Over 130 rivers provide inflow to the Caspian, with the Volga River being the largest. A second affluent, the Ural River, flows in from the north, and the Kura River flows into the sea from the west. In the past, the Amu Darya (Oxus) of Central Asia in the east often changed course to empty into the Caspian through a now-desiccated riverbed called the Uzboy River, as did the Syr Darya farther north.

 

 

The Caspian also has several small islands; they are primarily located in the north and have a collective land area of roughly 2,000 km2 (770 sq mi). Adjacent to the North Caspian is the Caspian Depression, a low-lying region 27 metres (89 ft) below sea level.

​

The Central Asian steppes stretch across the northeast coast, while the Caucasus mountains hug the western shore. The biomes to both the north and east are characterized by cold, continental deserts. 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.[2]

The Caspian Sea has numerous islands throughout, all of them near the coasts; none in the deeper parts of the sea. Ogurja Ada is the largest island. The island is 37 km (23 mi) long, with gazelles roaming freely on it. In the North Caspian, the majority of the islands are small and uninhabited, like the Tyuleniy Archipelago, an Important Bird Area (IBA), although some of them have human settlements.

​

​

​

​

 

 

 

 

 

 

 

 

​