The world's largest inland body of water is the Caspian Sea. Lying between Europe and Asia, it is bordered by Russia and Azerbaijan on the west, Kazakhstan and Turkmenistan on the north and east, and Iran on the south. The sea was named for the Kaspi, ancient peoples who once lived on its western shores.

Physical features

The Caspian Sea is nearly the size of Japan, covering an area of about 143,000 square miles (370,000 square kilometers). The sea has an elongated shape: it is about 750 miles (1,200 kilometers) long, but its average width is only 200 miles (320 kilometers). Three major rivers—the Volga, Ural, and Terek—empty into the Caspian from the north.

The Caspian is shallowest in the north. There the depth averages just 13 to 20 feet (4 to 6 meters). The deepest parts are in the south. In one place the sea floor lies 3,360 feet (1,024 meters) below the water's surface. The sea contains as many as 50 islands, most of them quite small.

Because of the Caspian's great length from north to south, it stretches across a number of different climates. The north has moderate temperatures, but the middle and much of the south can get quite hot. The eastern shores have a desert climate. Average annual rainfall ranges from 8 to 67 inches (20 to 170 centimeters) across the sea.

Economy

The Caspian Sea has long been famous for its sturgeon. These fish produce eggs that are made into caviar, a salty delicacy. The number of sturgeon greatly declined, however, as the water level of the Caspian dropped greatly during much of the 20th century. The lower sea level caused sturgeon spawning grounds to dry up. Too much fishing of sturgeons over the years is another reason why their numbers have fallen. Today sturgeon fishing is strictly controlled. To help make up for the decline in fishing, a seal industry has been developed in the northern Caspian. The main product is furs.

Today, however, the chief industry of the Caspian region is the production of oil and natural gas. Surrounding countries collect these products from the seabed and sell them to other countries. The Caspian is also used to ship oil and other products, including wood, cotton, rice, and grain.

Environmental issues

The production of oil and natural gas has been a major source of pollution in the Caspian area. Another is contaminated water that flows into the Caspian from the Volga and other rivers. These problems have been made worse by the changing water level of the sea. After the sea level stopped dropping in 1977, it started to rise. A rise of more than 7 feet (2.1 meters) since then has flooded some coastal areas. The flooding has destroyed homes and spread the sea's polluted water.