Black Sea, inland sea, c.159,600 sq mi (413,360 sq km), between SE Europe and Asia, connected with the Mediterranean Sea by the Bosporus, the Sea of Marmara, and the Dardanelles. It is c.750 mi (1,210 km) from east to west, up to 350 mi (560 km) wide, and has a maximum depth of 7,364 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 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 two 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 counterclockwise direction around the sea. There is little tidal action.

Pollution in the Black Sea has spurred surrounding nations to cooperate in instituting environmental safeguards; overfishing is also a significant problem and has altered the sea's ecosystem. The sea is subject to severe winter storms, and waterspouts are common in summer. Ice-free, it is the chief shipping outlet of the Ukraine and Russia; Odessa and Sevastopol in Ukraine and Novorossiysk in Russia are major ports. Other important ports are Constanţa in Romania; Varna and Burgas in Bulgaria; and Trabzon, Samsun, and Zonguldak in Turkey. The Black Sea region, especially in the S Crimea and W Caucasus, is a popular resort area.

History

The Black Sea was once part of a larger body that included the Caspian and Aral seas. In the Tertiary period, it was separated from the Caspian Sea and was linked to the Mediterranean Sea. Evidence suggests that more recently, about 7,600 years ago, at the end of a long dry period, it was flooded when the Mediterranean, having again become separate, broke through at the Bosporus, an event that may have scattered farmers from its shores into Europe and Asia. Some scientists have hypothesized that this event happened catastrophically and is the source of the biblical story of the Deluge.

The Pontus Euxinus [hospitable sea] of the ancients, the Black Sea was navigated and its shores colonized by the Greeks (8th-6th cent. B.C.) and later by the Romans (3d-1st cent. B.C.). Its importance increased with the founding of Constantinople (A.D. 330). In the 13th cent. the Genoese established colonies on the Black Sea, and from the 15th to the 18th cent. it was a Turkish "lake." The rise of Russia led to protracted dispute with the Ottoman Empire over control and use of the Bosporus and Dardanelles. In 1783, Russia annexed the Tatar Khanate of Crimea, which blocked its access to the sea, but the Treaty of Paris, which ended the Crimean War of 1856, frustrated Russia's expansionist ambitions, and Russia and its successor, the Soviet Union, retained limited influence in the region. In 1992, after the breakup of the Soviet Union, the Black Sea Economic Cooperation was established by nations surrounding the sea (not all members actually border the sea); it became a formal international organization in 1998. The six nations bordering the sea established the Black Sea Naval Cooperation Task Group in 2001 to promote cooperation on naval and environmental issues.

Sea between Europe and Asia. Bordered by Ukraine, Russia, Georgia, Turkey, Bulgaria, and Romania, it has a maximum depth of 7,250 ft (2,210 m). The Black Sea proper has an area of 163,000 sq mi (422,000 sq km). It is connected with the Aegean Sea through the Bosporus, the Sea of Marmara, and the Dardanelles, and with the Sea of Azov by Kerch Strait. It receives many rivers, including the Danube, Dniester, Bug, Dnieper, Kuban, Kinodotzinodotl, and Sakarya. The Crimean Peninsula (see Crimea) extends into it from the north. Created when structural upheavals in Asia Minor split off the Caspian basin from the Mediterranean Sea, the Black Sea gradually became isolated; salinity is now less than half that of the world's oceans. Though long popular for its resorts, it has suffered severe pollution in recent decades.

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