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Atlantic Ocean

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Earth's five oceans
     * Atlantic Ocean
     * Arctic Ocean
     * Indian Ocean
     * Pacific Ocean
     * Southern Ocean

   Atlantic Ocean

   The Atlantic Ocean is the second-largest ocean, covering approximately
   one-fifth of the Earth's surface. The ocean's name, derived from Greek
   mythology, means the "Sea of Atlas." The oldest known mention of this
   name is contained in The Histories of Herodotus around 450 BC (I 202).

   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. A man-made connection between
   the Atlantic and Pacific is provided by the Panama Canal. On the east,
   the dividing line between the Atlantic and the Indian Ocean is the 20°
   East meridian, running south from Cape Agulhas to Antarctica. The
   Atlantic is separated from the Arctic by a line from Greenland to
   northwestern Iceland and then from northeastern Iceland to the
   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  square kilometres (41,100,000  sq mi);
   without them, it has an area of 82,400,000 square kilometres
   (31,800,000 sq mi). 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  cubic kilometres
   (85,100,000  cu mi) and without them 323,600,000 cubic kilometres
   (77,640,000 cu mi).

   The average depths of the Atlantic, with its adjacent seas, is 3,338
   metres (10,932 ft); without them it is 3,926 metres (12,881 ft). The
   greatest depth, 8,605 metres (28,232 ft), is in the Puerto Rico Trench.
   The width of the Atlantic varies from 2,848 kilometres (1,770 mi)
   between Brazil and Liberia to about 4,830 kilometres (3,000 mi) between
   the United States and northern Africa.

Ocean bottom

   The principal feature of the bottom bathymetry ( terrain) of the
   Atlantic Ocean is a 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 kilometres (1,000
   mi). 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 and
   form 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 metres (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.

   The deep ocean floor is thought to be fairly flat, although numerous
   seamounts and some guyots exist. Several deeps or trenches are also
   found on the ocean floor. The Puerto Rico Trench, in the North
   Atlantic, is the deepest. The Laurentian Abyss is found off the eastern
   coast of Canada. In the South Atlantic, the South Sandwich Trench
   reaches a depth of 8,428 metres (27,651 ft). A third major trench, the
   Romanche Trench, is located near the equator and reaches a depth of
   about 7,454 metres (24,455 ft). The shelves along the margins of the
   continents constitute about 11% of the bottom topography. Several deep
   channels cut across the continental rise.

   Ocean sediments are composed of terrigenous, pelagic, and authigenic
   material. Terrigenous deposits consist of sand, mud, and rock particles
   formed by erosion, weathering, and volcanic activity on land and then
   washed to sea. These materials are found mostly on the continental
   shelves and are thickest off the mouths of large rivers or off desert
   coasts. Pelagic deposits, which contain the remains of organisms that
   sink to the ocean floor, include red clays and Globigerina, pteropod,
   and siliceous oozes. Covering most of the ocean floor and ranging in
   thickness from 60 to 3,300 metres (200 to 11,000 ft), they are thickest
   in the convergence belts and in the zones of upwelling. Authigenic
   deposits consist of such materials as manganese nodules. They occur
   where sedimentation proceeds slowly or where currents sort the
   deposits.

Water characteristics

   The Atlantic Ocean as seen from the west coast of Ireland on a fair
   day.
   Enlarge
   The Atlantic Ocean as seen from the west coast of Ireland on a fair
   day.

   On average, the Atlantic is the saltiest of the world's major oceans;
   the salinity of the surface waters in the open ocean ranges from 33 to
   37 parts per thousand (3.3 - 3.7%) by mass and varies with latitude and
   season. Surface salinity values are influenced by evaporation,
   precipitation, river inflow, and melting of sea ice. Although the
   minimum salinity values are found just north of the equator (because of
   heavy tropical rainfall), in general the lowest values are in the high
   latitudes and along coasts where large rivers flow into the ocean.
   Maximum salinity values occur at about 25° north and south of the
   equator, in subtropical regions with low rainfall and high evaporation.

   Surface water temperatures, which vary with latitude, current systems,
   and season and reflect the latitudinal distribution of solar energy,
   range from less than −2 ° C to 29 °C (28 ° F to 84 °F). Maximum
   temperatures occur north of the equator, and minimum values are found
   in the polar regions. In the middle latitudes, the area of maximum
   temperature variations, values may vary by 7 °C to 8 °C (13°F to 14°F).

   The Atlantic Ocean consists of four major water masses. The North and
   South Atlantic central waters constitute the surface waters. The
   sub-Antarctic intermediate water extends to depths of 1,000 metres
   (3,300 ft). The North Atlantic deep water reaches depths of as much as
   4,000 metres (13,200 ft). The Antarctic bottom water occupies ocean
   basins at depths greater than 4,000 metres (13,200 ft).

   Within the North Atlantic, ocean currents isolate a large elongated
   body of water known as the Sargasso Sea, in which the salinity is
   noticeably higher than average. The Sargasso Sea contains large amounts
   of seaweed and is also the spawning ground for the European eel.

   Because of the Coriolis effect, water in the North Atlantic circulates
   in a clockwise direction, whereas water circulation in the South
   Atlantic is counter-clockwise. The south tides in the Atlantic Ocean
   are semi- diurnal; that is, two high tides occur during each 24 lunar
   hours. The tides are a general wave that moves from south to north. In
   latitudes above 40° North some east-west oscillation occurs.

Climate

   Waves in the trade winds in the Atlantic Ocean—areas of converging
   winds that move along the same track as the prevailing wind—create
   instabilities in the atmosphere that may lead to the formation of
   hurricanes.
   Waves in the trade winds in the Atlantic Ocean—areas of converging
   winds that move along the same track as the prevailing wind—create
   instabilities in the atmosphere that may lead to the formation of
   hurricanes.

   The climate of the Atlantic Ocean and adjacent land areas is influenced
   by the temperatures of the surface waters and water currents as well as
   the winds blowing across the waters. Because of the ocean's great
   capacity for retaining heat, maritime climates are moderate and free of
   extreme seasonal variations. Precipitation can be approximated from
   coastal weather data and air temperature from the water temperatures.
   The oceans are the major source of the atmospheric moisture that is
   obtained through evaporation. Climatic zones vary with latitude; the
   warmest climatic zones stretch across the Atlantic north of the
   equator. The coldest zones are in the high latitudes, with the coldest
   regions corresponding to the areas covered by sea ice. Ocean currents
   contribute to climatic control by transporting warm and cold waters to
   other regions. Adjacent land areas are affected by the winds that are
   cooled or warmed when blowing over these currents. The Gulf Stream, for
   example, warms the atmosphere of the British Isles and northwestern
   Europe, and the cold water currents contribute to heavy fog off the
   coast of northeastern Canada (the Grand Banks area) and the
   northwestern coast of Africa. In general, winds tend to transport
   moisture and warm or cool air over land areas. Hurricanes develop in
   the southern part of the North Atlantic Ocean.

History

   The Atlantic Ocean appears to be the second youngest of the world's
   oceans, after the Southern Ocean. Evidence indicates that it did not
   exist prior to 180 million years ago, when the continents that formed
   from the breakup of the ancestral supercontinent, Pangaea, were being
   rafted apart by the process of seafloor spreading. The Atlantic has
   been extensively explored since the earliest settlements were
   established along its shores. The Vikings, Portuguese, and Christopher
   Columbus were the most famous among its early explorers. After
   Columbus, European exploration rapidly accelerated, and many new trade
   routes were established. As a result, the Atlantic became and remains
   the major artery between Europe and the Americas (known as
   transatlantic trade). Numerous scientific explorations have been
   undertaken, including those by the German Meteor expedition, Columbia
   University's Lamont Geological Observatory, and the United States Navy
   Hydrographic Office.

   Some important events in relation to the Atlantic:
     * In 1858, the first transatlantic telegraph cable was laid by Cyrus
       Field.
     * On April 14th 1912 the RMS Titanic sank after hitting an iceberg
       with loss of 1,593 people.
     * In 1919, the American NC-4 became the first airplane to cross the
       Atlantic (though it made a couple of landings on islands along the
       way).
     * Later in 1919, a British airplane piloted by Alcock and Brown made
       the first non-stop transatlantic flight, from Newfoundland to
       Ireland.
     * In 1921, the British were the first to cross the North Atlantic in
       an airship.
     * In 1922, the Portuguese were the first to cross the South Atlantic
       in an airship.
     * The first transatlantic telephone call was made on January 7, 1927.
     * In 1927, Charles Lindbergh made the first solo non-stop
       transatlantic flight in an airplane (between New York City and
       Paris).
     * In 1998, Ben Lecomte was the first person to swim across the
       Atlantic Ocean, stopping for only one week in the Azores.
     * After rowing for 81 days and 4,767 kilometres (2,962 mi), on
       December 3, 1999, Tori Murden became the first woman to cross the
       Atlantic Ocean by rowboat alone when she reached Guadeloupe from
       the Canary Islands.

Economy

   The ocean has also contributed significantly to the development and
   economy of the countries around it. Besides its major transatlantic
   transportation and communication routes, the Atlantic offers abundant
   petroleum deposits in the sedimentary rocks of the continental shelves
   and the world's richest fishing resources, especially in the waters
   covering the shelves. The major species of fish caught are cod,
   haddock, hake, herring, and mackerel. The most productive areas include
   the Grand Banks of Newfoundland, the shelf area off Nova Scotia,
   Georges Bank off Cape Cod, the Bahama Banks, the waters around Iceland,
   the Irish Sea, the Dogger Bank of the North Sea, and the Falkland
   Banks. Eel, lobster, and whales have also been taken in great
   quantities. All these factors, taken together, tremendously enhance the
   Atlantic's great commercial value. Because of the threats to the ocean
   environment presented by oil spills, marine debris, and the
   incineration of toxic wastes at sea, various international treaties
   exist to reduce some forms of pollution.

Terrain

   Atlantic bathymetry
   Enlarge
   Atlantic bathymetry

   The surface is usually covered with sea ice in the Labrador Sea,
   Denmark Strait, and Baltic Sea from October to June. There is a
   clockwise warm-water gyre in the northern Atlantic, and a
   counter-clockwise warm-water gyre in the southern Atlantic. The ocean
   floor is dominated by the Mid-Atlantic Ridge, a rugged north-south
   centerline for the entire Atlantic basin, first discovered by the
   Challenger Expedition.

   The Atlantic Ocean has irregular coasts indented by numerous bays,
   gulfs, and seas. These include the Caribbean Sea, Gulf of Mexico, Gulf
   of St. Lawrence, Mediterranean Sea, Black Sea, English Channel , North
   Sea, Labrador Sea, Baltic Sea , Gulf of Maine , Bay of Fundy and
   Norwegian- Greenland Sea. Islands in the Atlantic Ocean include Faroe
   Islands, Greenland, Iceland, Rockall, Great Britain, Ireland, Fernando
   de Noronha, the Azores, the Madeira Islands, the Canaries, the Cape
   Verde Islands, Sao Tome e Principe, Newfoundland, Bermuda, the West
   Indies, Ascension, St. Helena, Trindade, Martin Vaz, Tristan da Cunha,
   the Falkland Islands, and South Georgia Island.

Elevation extremes

     * lowest point: Milwaukee Deep in the Puerto Rico Trench −8,605
       metres (28,232 ft)
     * highest point: sea level, 0 metres

Natural hazards

   Icebergs are common in the Davis Strait, Denmark Strait, and the
   northwestern Atlantic Ocean from February to August and have been
   spotted as far south as Bermuda and the Madeira Islands. Ships are
   subject to superstructure icing in extreme northern Atlantic from
   October to May. Persistent fog can be a maritime hazard from May to
   September, as can hurricanes north of the equator (May to December).

   The Bermuda Triangle is popularly believed to be the site of numerous
   aviation and shipping incidents because of unexplained and supposedly
   mysterious causes, but coast guard records do not support this belief.

Current environmental issues

   Endangered marine species include the manatee, seals, sea lions,
   turtles, and whales. Drift net fishing is killing dolphins, albatrosses
   and other seabirds ( petrels, auks), hastening the decline of fish
   stocks and contributing to international disputes. There is municipal
   sludge pollution off the eastern United States, southern Brazil, and
   eastern Argentina; oil pollution in the Caribbean Sea, Gulf of Mexico,
   Lake Maracaibo, Mediterranean Sea, and North Sea; and industrial waste
   and municipal sewage pollution in the Baltic Sea, North Sea, and
   Mediterranean Sea.

   On June 7, 2006, Florida's wildlife commission voted to take the
   manatee off of the state's endangered species list. Some
   environmentalists worry that this could erode safeguards for the
   popular sea creature.

Major ports and harbours

North America

United States

     * Baltimore, Maryland
     * Boston, Massachusetts
     * Port Canaveral, Florida
     * Charleston, South Carolina
     * Corpus Christi, Texas
     * Port Everglades
     * Houston, Texas
     * Jacksonville, Florida
     * Port of Miami-Dade
     * Morehead City, North Carolina
     * Nantucket, Massachusetts
     * New Haven, Connecticut
     * New London, Connecticut
     * New Orleans, Louisiana
     * New York, New York
     * Newport News, Virginia
     * Norfolk, Virginia
     * Port of Palm Beach
     * Port Newark-Elizabeth Marine Terminal
     * Portland, Maine
     * Portsmouth, New Hampshire
     * Providence, Rhode Island
     * Savannah, Georgia
     * Tampa, Florida
     * Wilmington, North Carolina

Canada

     * Charlottetown, Prince Edward Island
     * Corner Brook, Newfoundland and Labrador
     * Digby, Nova Scotia
     * Halifax, Nova Scotia
     * Happy Valley-Goose Bay, Newfoundland and Labrador
     * Saint John, New Brunswick
     * Shelburne, Nova Scotia
     * Sept-Îles, Quebec
     * St. John's, Newfoundland and Labrador
     * Sydney, Nova Scotia
     * Yarmouth, Nova Scotia
     * Calgary, Alberta

Other North American locales

     * Puerto Cortés, Honduras
     * Willemstad, Netherlands Antilles

Europe

     * Aberdeen, United Kingdom
     * A Coruña, Spain
     * Ålesund, Norway
     * Amsterdam, Netherlands
     * Antwerp, Belgium
     * Avilés, Spain
     * Belfast, United Kingdom
     * Bergen, Norway
     * Bilbao, Spain
     * Bodø, Norway
     * Bordeaux, France
     * Bremen, Germany
     * Brest, France
     * Bristol, United Kingdom
     * Cadiz, Spain
     * Cherbourg-Octeville, France
     * Cork, Republic of Ireland
     * Dublin Port, Republic of Ireland
     * Dunkirk, France
     * Edinburgh, United Kingdom
     * Esbjerg, Denmark
     * Funchal, Portugal
     * Galway, Republic of Ireland
     * Gijón, Spain
     * Glasgow, United Kingdom
     * Gothenburg, Sweden
     * Hafnarfjörður, Iceland
     * Hamburg, Germany
     * Las Palmas de Gran Canaria, Canary Islands
     * Le Havre, France
     * Lisbon, Portugal
     * Liverpool, United Kingdom
     * London, United Kingdom
     * Milford Haven, United Kingdom
     * Nantes, France
     * Narvik, Norway
     * Newcastle upon Tyne, United Kingdom
     * Newport, United Kingdom
     * Normandy, France
     * Oslo, Norway
     * Ostend, Belgium
     * Penzance, United Kingdom
     * Peterhead, United Kingdom
     * Porto, Portugal
     * Portsmouth, United Kingdom
     * Reykjavík, Iceland
     * Rotterdam, Netherlands
     * Saint-Nazaire, France
     * Santa Cruz de Tenerife, Canary Islands
     * Santander, Spain
     * Seville, Spain
     * Sines, Portugal
     * Southampton, United Kingdom
     * Stavanger, Norway
     * Swansea, United Kingdom
     * Tromsø, Norway
     * Trondheim, Norway
     * Tórshavn, Faroe Islands
     * Vigo, Spain

South America

     * Quequen Argentina
     * Bahia Blanca, Argentina
     * Mar del Plata, Argentina
     * Cayenne, French Guiana
     * Punta Arenas, Chile
     * Puerto Williams, Chile
     * Georgetown, Guyana
     * Iquitos, Peru (via the Amazon)
     * Pucallpa, Peru (via the Amazon)
     * Yurimaguas, Peru (via the Amazon)
     * Paramaribo, Suriname

Brazil

     * Belém, Pará
     * São Luís , Maranhão
     * Fortaleza, Ceará
     * Recife, Pernambuco
     * Suape,Pernambuco
     * Maceió, Alagoas
     * Aratu, Bahia
     * Salvador, Bahia
     * Vitória, Espírito Santo
     * Rio de Janeiro, Rio de Janeiro
     * São Sebastião, São Paulo
     * Santos, São Paulo
     * Paranaguá, Paraná
     * Itajaí, Santa Catarina
     * São Francisco do Sul, Santa Catarina
     * Porto Alegre, Rio Grande do Sul
     * Rio Grande, Rio Grande do Sul

Africa

     * Abidjan, Côte d'Ivoire
     * Accra, Ghana
     * Banjul, The Gambia
     * Bissau, Guinea-Bissau
     * Cape Town, South Africa
     * Casablanca, Morocco
     * Conakry, Guinea
     * Cotonou, Benin
     * Dakar, Senegal
     * Douala, Cameroon
     * Lagos, Nigeria
     * Libreville, Gabon
     * Lomé, Togo
     * Luanda, Angola
     * Malabo, Equatorial Guinea
     * Monrovia, Liberia
     * Nouakchott, Mauritania
     * Port Harcourt, Nigeria
     * Porto-Novo, Benin
     * Praia, Cape Verde
     * Rabat, Morocco
     * Saldanah, South Africa
     * Tangier, Morocco
     * Walvis Bay, Namibia

   Note: This list of ports and harbors is very short. For instance,
   Panama alone has 30 ports.
   Retrieved from " http://en.wikipedia.org/wiki/Atlantic_Ocean"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
