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The Atlantic Ocean is the world's second largest ocean with a total area of about 106,400,000 square kilometres (41,100,000 sq mi). It covers approximately 20 percent of the Earth's surface. "Atlantic" refers to Atlas of Greek mythology.
Geologic history[change | change source]
The Atlantic formed when the Americas moved west from Eurasia and Africa. This began sometime in the Cretaceous period, roughly 135 million years ago. It was part of the break-up of the supercontinent Pangaea.
The east coast of South America is shaped somewhat like the west coast of Africa, and this gave a clue that continents moved over long periods of time (continental drift). The Atlantic Ocean is still growing now, because of sea-floor spreading from the mid-Atlantic Ridge, while the Pacific Ocean is said to be shrinking because the sea floor is folding under itself.
Geography[change | change source]
The Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea and Barents Sea. It connects with the Mediterranean Sea though Strait of Gibraltar.
In the southeast, the Atlantic merges into the Indian Ocean. The 20° East meridian defines its border.
The Atlantic ocean is second in size to the Pacific. It occupies an area of about 106,400,000 square kilometres (41,100,000 sq mi). The volume of the Atlantic with its adjacent seas is 354,700,000 cubic kilometers.
The average depth of the Atlantic with its adjacent seas, is 3,339 metres (1,826 fathoms; 10,955 ft). The greatest depth is Milwaukee Deep near Puerto Rico with 8,380 metres (4,580 fathoms; 27,490 ft)
Gulf Stream[change | change source]
The Atlantic Ocean has important ocean currents. One of these, called the Gulf Stream, flows across the North Atlantic. Water gets heated by the sun in the Caribbean Sea and then moves northwest toward the North Pole. This makes France, Ireland, Britain, Iceland, and Norway in Europe much warmer in winter than Newfoundland and Nova Scotia in Canada. Without the Gulf Stream, the climates of northeast Canada and northwest Europe might be the same, because these places are about the same distance from the North Pole.
There are currents in the South Atlantic too, but the shape of this sea means that it has less effect on South Africa.
Geology[change | change source]
The main feature of the seabed of the Atlantic Ocean is a large underwater mountain chain that runs through it from north to south, called the Mid-Atlantic Ridge. This is at the boundary of four tectonic plates: Eurasian, North American, South American and African. The ridge extends from Iceland in the north to about 58° south.
The salinity of the surface waters of the open ocean ranges from 33-37 parts per thousand and varies with latitude and season.
Other websites[change | change source]
- LA Times special Altered Oceans
- Oceanography Image of the Day, from the Woods Hole Oceanographic Institution
- National Oceanic and Atmospheric Administration
- NOAA In-situ Ocean Data Viewer Plot and download ocean observations
- CIA World Factbook information about Atlantic Ocean
- Oceans at the Open Directory Project