an almost landlocked sea of the Atlantic Ocean off the southeastern coast of North America, between the Florida and Yucatán peninsulas and the island of Cuba. Area, 1,543 sq km; water volume, 2,332,000 cu km. In the east it is connected with the Atlantic Ocean by the Straits of Florida, and in the south it is connected with the Caribbean by the Yucatán Channel. The Gulf of Mexico has a well-developed basin descending to 5,203 m. The central section is an abyssal plateau with a cluster of underwater hills about 300 m high. On the north, south, and east the plateau is rimmed by shelves up to 250 km wide; the northwestern shelf is rich in oil.
The climate is tropical in the south and subtropical in the north. The air temperature is about 28°C in summer, and in winter it ranges from 14−15°C in the north (sometimes falling to 0°C) to 21−23°C in the south. Evaporation (1,000–1,750 mm) exceeds precipitation (1,000–1,200 mm per year). Hurricanes are frequent in summer and fall. In summer the water temperature is 29°C on the surface and 30−31°C in the shallows; in winter temperatures range from 18°C in the north to 25°C in the south. The salinity of the surface water is generally 36.0–36.9 parts per thousand. At depths of more than 2,000 m, temperature (4.3°C) and salinity (34.98 parts per thousand) are almost constant and equal. The surface currents generally move in a clockwise direction. The Yucatán Current, entering the gulf from the Caribbean Sea, has a speed of 50–200 cm per sec, and the Florida Current, which flows out of the gulf and begins the Gulf Stream, has speeds to 300 cm cu sec and a discharge of 25 million cu m per sec. Tides are primarily diurnal, with heights of 0.3–0.6 m, but semidiurnal and mixed tides also occur. The open sea has little plankton, but it is plentiful on the shelves (1 g per cu m). Fish, chiefly herring and menhaden, oysters, shrimp, lobsters, and turtles are caught on the shelves, and tuna and sharks are caught throughout the gulf. The principal ports are New Orleans (USA), Veracruz (Mexico), and Havana (Cuba).
A. S. POLOSIN