Black Sea, inland sea, c.
159,600sq mi (413,360sq km), between SE Europe and Asia, connected with
the Mediterranean Sea by the Bosphorus, the Sea of Marmara, and the
Dardanelles. It is c. 750 mi (1,210 km) from 7,367 ft (2,245 m). Its
largest arm is the sea of Azov, which joins it through the Kerch Strait.
The Black Sea is enclosed by Ukraine on the north, Russia on the
northeast, Georgia on the east, Turkey on the south, and Bulgaria and
Romania on the west.
The Black Sea was once part of a larger body that included
the Caspian and Aral seas. In the Tertiary period, it was separeted from
the Caspian Sea and was linked to the Mediterranean Sea. Growing evidence
suggests that more recently, about 7,600 years ago, at the end of a long
dry period, it was flooded suddenly when the Mediterannean, having again
become separate, broke through at the Bosphorus, an event that may have
scattered farmers from its shores into Europe and Asia. The Dnieper,
Southern Buh, Dniester, and Danube rivers are its principal feeders, the
don and Kuban rivers flow into the Sea of Azov. The rivers flowing into
the northern part of the Black Sea carry much silt and form deltas,
sandbars, and lagoons along the generally low and sandy northern coast.
The southern coast is steep and rocky. The Black Sea has tow layers of
water of different densities. The heavily saline bottom layer has little
movement and contains hydrogen sulfide, it has no marine life. The top
layer, much less saline and richer in fish, flows in a countewrclockwise
direction around the sea. There is little tidal action.