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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. The first part of its name refers to Atlas of Greek mythology.
Scientists say that millions of years ago, there was only one ocean, and that most of the land in the world was joined together over where the Atlantic Ocean is now. Eventually, they think an enormous crack developed in the ground due to volcanic forces, and that the continents started ever so slowly drifting away from each other. The crack would have filled with water from rivers, and eventually the sea might have broken through from the north and the south. Even to this day, the east coast of the Americas is shaped somewhat like the west coast of Africa, but the difference is actually much greater than it might appear, so it is not really an exact fit or even a close one. 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.
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.
Features[change | change source]
The Atlantic is shaped like the letter 'S', the second largest ocean on Earth, after the Pacific and comprises approximately 20% of its surface. Specifically the area is 106.5 million km² including its marginal seas (including the Arctic ocean), if the marginal seas are excluded comprising 82.4 million km². The volume of water is 354.7 million km³, if the adjacent seas, or 323.6 km³ are counted, if not considered. The width of the Atlantic varies from 2,848 km (between Brazil and Liberia), the 4,870 km (between the United States and Morocco). Its maximum is 11,800 km, a distance that goes from the Gulf of Mexico to Georgia, on the shores of the Black Sea. It has an average depth of 3,900 m. Despite this, the number of islands is relatively small. The salinity of the Atlantic Ocean is about 36 grams of salt per liter of water and the most fished species are sardines, herring and cod. Furthermore, it is the most difficult ocean of the Earth from a commercial point of view.
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, which is formed 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 latitude, achieving a maximum width of 1,600 km, approximately. The water depth over the dorsal less than 2700 meters in many areas, and some peaks above water, forming islands. The seafloor is believed to be generally quite flat, although there is abundant seamounts, plus deep pits. The Puerto Rico Trench, in the North Atlantic, is the deepest. In the South Atlantic, the South Sandwich Trench reaches a depth of 8,428 m. A third grave, grave Romanche, is located near the Ecuador and has 7,760 m. Furthermore, there are a number of deep channels cut platforms. Ocean sediments are composed of terrigenous, pelagic, and material. Terrigenous deposits consist of sand, mud, and rock particles formed by erosion, wear, and volcanic activity on land and then transported to the sea. These materials are found abundantly in the continental shelves and are further ahead of the mouths of large rivers or desert coasts.
Water Features[change | change source]
The salinity of surface waters in the open ocean ranges from 33-37 parts per thousand and varies with latitude and season. Although the minimum salinity values are found just north of Ecuador, in general the lowest values are in the high latitudes and coasts where large rivers flow into the ocean. The maximum salinity occurs at approximately 25 ° north latitude. Surface salinity is influenced by evaporation, precipitation, river flows and thawing. Surface temperatures, which vary with latitude, current systems, stations and reflect the distribution of solar flux as a function of latitude, ranging from less than 2-29 ° C. Maximum temperatures occur in northern Ecuador, and minimum in the polar regions. A middle latitudes, where the maximum variations are, the values may vary 7 or 8 ° C. The Atlantic Ocean consists of four major water masses. The central water is surface water. The tides are a general wave that moves from south to north.
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