Evaporation, precipitation, river inflow and sea ice melting influence surface salinity values. Sa surface, sans les mers bordières, est de l'ordre de 82 millions de ki [58], West Gondwana (South America and Africa) broke up in the Early Cretaceous to form the South Atlantic. During the 21st century some species have shown weak signs of recovery, including Greenland halibut, yellowtail flounder, Atlantic halibut, haddock, spiny dogfish, while other stocks shown no such signs, including cod, witch flounder, and redfish. [6], The Gulf Stream and its northern extension towards Europe, the North Atlantic Drift is thought to have at least some influence on climate. The exact timing is controversial with estimates ranging from 200 to 170 Ma. [13], The Pond is a term often used by British and American speakers in context to the Northern Atlantic Ocean, as a form of meiosis, or sarcastic understatement. [51], The opening of the Atlantic Ocean coincided with the initial break-up of the supercontinent Pangaea, both of which were initiated by the eruption of the Central Atlantic Magmatic Province (CAMP), one of the most extensive and voluminous large igneous provinces in Earth's history associated with the Triassic–Jurassic extinction event, one of Earth's major extinction events. Almost half of the stocks are fished at biologically unsustainable levels. The south tides in the Atlantic Ocean are semi-diurnal; that is, two high tides occur during every 24 lunar hours. By end of the 17th century, the volume of the Trans-Atlantic trade had surpassed that of the Mediterranean trade. In the early 1990s, this finally resulted in the collapse of the Atlantic northwest cod fishery. This involved little guesswork because the idea of sonar is straight forward with pulses being sent from the vessel, which bounce off the ocean floor, then return to the vessel. The opening of the Northern Atlantic closely followed the margins of its predecessor, the Iapetus Ocean, and spread from the Central Atlantic in six stages: Iberia–Newfoundland, Porcupine–North America, Eurasia–Greenland, Eurasia–North America. Round sardinella was an important species in the 1990s but is now considered overfished. Climatic zones vary with latitude; the warmest zones stretch across the Atlantic north of the equator. [17], The Atlantic has irregular coasts indented by numerous bays, gulfs and seas. Arctic saithe and haddock are considered fully fished; Sand eel is overfished as was capelin which has now recovered to fully fished. [86], In the North-West Atlantic landings have decreased from 4.2 million tons in the early 1970s to 1.9 million tons in 2013. [45] Recent but disputed research suggests that eels possibly use Earth's magnetic field to navigate through the ocean both as larvae and as adults. Besides major transatlantic transportation and communication routes, the Atlantic offers abundant petroleum deposits in the sedimentary rocks of the continental shelves. [26] The depth of water at the apex of the ridge is less than 2,700 m (1,500 fathoms; 8,900 ft) in most places, while the bottom of the ridge is three times as deep. Drift net fishing can kill dolphins, albatrosses and other seabirds (petrels, auks), hastening the fish stock decline and contributing to international disputes. A new model", "History of NOAA Ocean Exploration: Timeline", "The human genetic history of the Americas: the final frontier", "Two millennia of North Atlantic seasonality and implications for Norse colonies", "Global continental and ocean basin reconstructions since 200Ma", "Tracing the flow of North Atlantic Deep Water using chlorofluorocarbons", "On the water masses and mean circulation of the South Atlantic Ocean", "A new scheme for the opening of the South Atlantic Ocean and the dissection of an Aptian salt basin", "The North Atlantic subpolar gyre in four high-resolution models", "Mapping of the Puerto Rico Trench, the Deepest Part of the Atlantic, is Nearing Completion", "The Red Atlantic: American Indigenes and the Making of the Modern World, 1000–1927", "Changes in tropical cyclone number, duration, and intensity in a warming environment", "Map of Atlantic Coast of North America from the Chesapeake Bay to Florida", https://en.wikipedia.org/w/index.php?title=Atlantic_Ocean&oldid=994576088, Short description is different from Wikidata, Wikipedia introduction cleanup from December 2020, Articles covered by WikiProject Wikify from December 2020, All articles covered by WikiProject Wikify, All Wikipedia articles written in American English, Articles using infobox body of water without pushpin map, Articles using infobox body of water without image bathymetry, Articles containing Ancient Greek (to 1453)-language text, Articles to be expanded from December 2020, Articles with dead external links from June 2019, Articles with permanently dead external links, Articles with dead external links from May 2019, Articles with dead external links from July 2017, Wikipedia articles with WORLDCATID identifiers, Creative Commons Attribution-ShareAlike License, 111,866 km (69,510 mi) including marginal seas, This page was last edited on 16 December 2020, at 12:50. Associated offshore basaltic flows reach as far south as the Falkland Islands and South Africa. Since man-made substances were introduced into the environment, the path of the NADW can be traced throughout its course by measuring tritium and radiocarbon from nuclear weapon tests in the 1960s and CFCs. Correspondingly, the extent and number of oceans and seas vary. On the African east coast the small cyclonic Angola Gyre lies embedded in the large subtropical gyre. The Atlantic Ocean is the second-largest of the world's oceans, with an area of about 106,460,000 km 2 (41,100,000 sq mi). Contradictory data from archaeology and genetics will most likely deliver future hypotheses that will, eventually, confirm each other. [69] The European coasts of the North Atlantic were permanently populated about 9–8.5 thousand years ago. The apparent fit between the coastlines of the two continents was noted on the first maps that included the South Atlantic and it was also the subject of the first computer-assisted plate tectonic reconstructions in 1965. [6], The Atlantic harbors petroleum and gas fields, fish, marine mammals (seals and whales), sand and gravel aggregates, placer deposits, polymetallic nodules, and precious stones. Stocks of northern shrimp and Norwegian lobster are in good condition. There this water is cooled during winter and forms return currents that merge along the eastern continental slope of Greenland where they form an intense (40–50 Sv) current which flows around the continental margins of the Labrador Sea. [1][18], Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 (41,100,000 sq mi) or 23.5% of the global ocean and has a volume of 310,410,900 km3 (74,471,500 cu mi) or 23.3% of the total volume of the earth's oceans. [93] If the AMO were responsible for SST variability, the AMOC would have increased in strength, which is apparently not the case. During the latest glacial stages, the now-submerged plains of the Agulhas Bank were exposed above sea level, extending the South African coastline farther south by hundreds of kilometers. Growth was more rapid in non-absolutist countries, such as Britain and the Netherlands, and more limited in absolutist monarchies, such as Portugal, Spain, and France, where profit mostly or exclusively benefited the monarchy and its allies. Au delà de 1000 m de profondeur la température est relativement homogène. North Atlantic Central Water flows into South Atlantic Central Water at 15°N. In 1922 a historic moment in cartography and oceanography occurred. These include the Baltic Sea, Black Sea, Caribbean Sea, Davis Strait, Denmark Strait, part of the Drake Passage, Gulf of Mexico, Labrador Sea, Mediterranean Sea, North Sea, Norwegian Sea, almost all of the Scotia Sea, and other tributary water bodies. La figure 4.3 représente la distribution moyenne de la température sur une coupe de l'océan Atlantique Ouest.Cette figure illustre bien le confinement des températures élevées dans la partie supérieure de l'océan. The extent of the volcanism has been estimated to 4.5×106 km2 (1.7×106 sq mi) of which 2.5×106 km2 (9.7×105 sq mi) covered what is now northern and central Brazil. [6] 44% of stocks are being fished at unsustainable levels. For their own safety, the crew jettisoned two nuclear bombs, which were never recovered. A third of this water becomes part of the deep portion of the North Atlantic Deep Water (NADW). Icebergs are common from early February to the end of July across the shipping lanes near the Grand Banks of Newfoundland. Although the lowest salinity values are 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 enter. The wide range of salinities in the North Atlantic is caused by the asymmetry of the northern subtropical gyre and the large number of contributions from a wide range of sources: Labrador Sea, Norwegian-Greenland Sea, Mediterranean, and South Atlantic Intermediate Water. The NADW, in its turn, feeds the meridional overturning circulation (MOC), the northward heat transport of which is threatened by anthropogenic climate change. [2][3] It covers approximately 20 percent of Earth's surface and about 29 percent of its water surface area. Other hunter-gatherers followed in waves interrupted by large-scale hazards such as the Laacher See volcanic eruption, the inundation of Doggerland (now the North Sea), and the formation of the Baltic Sea. [37], The clockwise warm-water North Atlantic Gyre occupies the northern Atlantic, and the counter-clockwise warm-water South Atlantic Gyre appears in the southern Atlantic. [6], The shelves of the Atlantic hosts one of the world's richest fishing resources. In La Riera Cave (23–13 kya) in Asturias, Spain, only some 26,600 molluscs were deposited over 10 kya. [53], The formation of the Central American Isthmus closed the Central American Seaway at the end of the Pliocene 2.8 Ma ago. [32] The deep ocean floor is thought to be fairly flat with occasional deeps, abyssal plains, trenches, seamounts, basins, plateaus, canyons, and some guyots. In the 1870s, the Challenger expedition discovered parts of what is now known as the Mid-Atlantic Ridge, or: An elevated ridge rising to an average height of about 1,900 fathoms [3,500 m; 11,400 ft] below the surface traverses the basins of the North and South Atlantic in a meridianal direction from Cape Farewell, probably its far south at least as Gough Island, following roughly the outlines of the coasts of the Old and the New Worlds. [62], In the southern segment the Early Cretaceous (133–130 Ma) intensive magmatism of the Paraná–Etendeka Large Igneous Province produced by the Tristan hotspot resulted in an estimated volume of 1.5×106 to 2.0×106 km3 (3.6×105 to 4.8×105 cu mi). Maximum salinity values occur at about 25° north and south, in subtropical regions with low rainfall and high evaporation. The oldest known mentions of an "Atlantic" sea come from Stesichorus around mid-sixth century BC (Sch. Fisheries have, however, undergone significant changes since the 1950s and global catches can now be divided into three groups of which only two are observed in the Atlantic: fisheries in the Eastern Central and South-West Atlantic oscillate around a globally stable value, the rest of the Atlantic is in overall decline following historical peaks. In the North-East Atlantic 21% of stocks are considered overfished. Changes in the formation of NADW have been linked to global climate changes in the past. Together these three tectonic forces are slowly developing into a new subduction system in the eastern Atlantic Basin. [66] [86], In 1497 John Cabot became the first Western European since the Vikings to explore mainland North America and one of his major discoveries was the abundant resources of Atlantic cod off Newfoundland. ", "The great American schism: divergence of marine organisms after the rise of the Central American Isthmus", "On the Movements of the North Atlantic Subpolar Front in the Preinstrumental Past", "Coastal South Africa and the Coevolution of the Modern Human Lineage and the Coastal Adaptation", "Stone age people in a changing South African greater Cape Floristic Region", "Stability of the thermohaline circulation under millennial CO2 forcing and two alternative controls on Atlantic salinity", "The Discovery of America: The first Americans may have swept the Western Hemisphere and decimated its fauna within 1000 years", "Extensive 200-million-year-old continental flood basalts of the Central Atlantic Magmatic Province", "Why did modern human populations disperse from Africa ca. Arctic Intermediate Water, flows from north to become the source for North Atlantic Deep Water south of the Greenland-Scotland sill. [95], Ocean between Europe, Africa and the Americas, "Atlantic", "North Atlantic", "South Atlantic", and "Atlantic Basin" redirect here. Précision : Cette carte de température de la mer a été realisée à partir des données de l'analyse SST de Medspiration (précision d'environ 2km) pour l'analyse France, et à partir de l'analyse RGHSST 0.083° deg d'hier pour la carte monde. [24], Continental shelves in the Atlantic are wide off Newfoundland, southernmost South America, and north-eastern Europe. Because of the ocean's great capacity to store and release heat, maritime climates are more moderate and have less extreme seasonal variations than inland climates. Following these explorations, Spain and Portugal quickly conquered and colonized large territories in the New World and forced the Amerindian population into slavery in order to explore the vast quantities of silver and gold they found. [59][60] This magnificent fit, however, has since then proven problematic and later reconstructions have introduced various deformation zones along the shorelines to accommodate the northward-propagating break-up.