Caspian Sea
The wide and endorheic Caspian Sea has a north–south orientation and its main freshwater inflow, the Volga River, enters at the shallow north end. Two deep basins occupy its central and southern areas. These facts lead to horizontal differences in temperature, salinity, and ecology. The Caspian Sea spreads out over nearly 750 miles (1,200 km) from north to south, with an average width of 200 miles (320 km). It covers a region of around 149,200 square miles (386,400 square km)—bigger than the region of Japan—and its surface is about 90 feet (27 meters) below sea level. The sea bed in the southern part reaches as low as 1,023 m (3,356 ft) below sea level, which is the second lowest natural depression on earth after Lake Baikal (−1,180 m, −3,871 ft). The ancient inhabitants of its coast perceived the Caspian Sea as an ocean, probably because of its saltiness and large size.
Garabogazköl
The salinity of the bay is about 35%, compared to the Caspian Sea's 1.2%, and 3–4% for the bulk of the world's oceans. Because of the exceptionally high salinity, comparable to the Dead Sea, it has practically no marine vegetation. Large evaporite, mostly salt deposits accumulated at the south shore were harvested by the local population since the 1920s, but in the 1930s manual collection stopped and the industry shifted northwest to its present center near Garabogaz. From the 1950s on, ground water was pumped from levels lower than the bay itself, yielding more valuable types of salts. In 1963 construction began at Garabogaz on a modern plant for increased production of salines, all the year round and independently of natural evaporation. This plant was completed in 1973.
In March 1980, the barrier to the Caspian was blocked, due to concerns evaporation was accelerating a fall in Caspian Sea level, reducing water levels. The resulting "salt bowl" caused widespread problems of blowing salt, reportedly poisoning the soil and causing health problems for hundreds of kilometers downwind to the east. In 1984 the lake was completely dry. In June 1992, when Caspian Sea levels were rising again, the barrier was breached, allowing Caspian water to again refill Garabogazköl. The remnants of the breached dam can be seen in the satellite photo of the inlet, near the Caspian Sea entrance.