Atlantic Ocean

Photo Courtesy of CIA World Factbook

The Atlantic Ocean is Earth's second-largest ocean, covering approximately one-fifth of its surface. The ocean's name, derived from Greek mythology, means the "Sea of Atlas".

This ocean occupies an elongated, S-shaped basin extending in a north-south direction and is divided into the North Atlantic and South Atlantic by equatorial counter currents at about 8° north latitude. Bounded by the Americas on the west and Europe and Africa on the east, the Atlantic is linked to the Pacific Ocean by the Arctic Ocean on the north and the Drake Passage on the south. An artificial connection between the Atlantic and Pacific is also provided by the Panama Canal. On the east, the dividing line between the Atlantic and the Indian Ocean is the 20° east meridian. The Atlantic is separated from the Arctic Ocean by a line from Greenland to northwestern Iceland and then from northeastern Iceland to southernmost tip of Spitsbergen and then to North Cape in northern Norway.

Covering approximately 20% of Earth's surface, the Atlantic Ocean is second only to the Pacific in size. With its adjacent seas it occupies an area of about 106,400,000 km² (41,100,000 square miles); without them, it has an area of 82,400,000 km² (31,800,000 mi²). The land area that drains into the Atlantic is four times that of either the Pacific or Indian oceans. The volume of the Atlantic Ocean with its adjacent seas is 354,700,000 km³ (85,100,000 mi³) and without them 323,600,000 km³ (77,640,000 mi³).

The average depth of the Atlantic, with its adjacent seas, is 3,332 m (10,932 ft); without them it is 3,926 m (12,881 ft). The greatest depth, 8,605 m (28,232 ft), is in the Puerto Rico Trench. The width of the Atlantic varies from 2,848 km (1,770 miles) between Brazil and Liberia to about 4,830 km (3,000 miles) between the United States and northern Africa.

The principal feature of the bottom topography of the Atlantic Ocean is a great submarine mountain range called the Mid-Atlantic Ridge. It extends from Iceland in the north to approximately 58° south latitude, reaching a maximum width of about 1,600 km (1,000 miles). A great rift valley also extends along the ridge over most of its length. The depth of water over the ridge is less than 2,700 m (8,900 ft) in most places, and several mountain peaks rise above the water, forming islands. The South Atlantic Ocean has an additional submarine ridge, the Walvis Ridge.

The Mid-Atlantic Ridge separates the Atlantic Ocean into two large troughs with depths averaging between 3,700 and 5,500 m (12,000 and 18,000 ft). Transverse ridges running between the continents and the Mid-Atlantic Ridge divide the ocean floor into numerous basins. Some of the larger basins are the Guiana, North American, Cape Verde, and Canaries basins in the North Atlantic. The largest South Atlantic basins are the Angola, Cape, Argentina, and Brazil basins.