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88-656: In 1471, Portuguese explorers encountered fishing villages rich with ivory and gold along the Atlantic coast of modern-day Ghana, which the Portuguese called the Gold Coast. The prospect of trade in the Gold Coast region helped spur the construction of the fortress São Jorge da Mina (St. George of the Mine) in 1482, which soon came to be known as Elmina Castle, derived from the Portuguese term "el mina" ("the mine"). The castle

176-492: A World Heritage Site for their geological value, four of them are considered of "Outstanding Universal Value" based on their cultural and natural criteria: Þingvellir , Iceland; Landscape of the Pico Island Vineyard Culture , Portugal; Gough and Inaccessible Islands , United Kingdom; and Brazilian Atlantic Islands: Fernando de Noronha and Atol das Rocas Reserves, Brazil. Continental shelves in

264-412: A municipality in the area. Native governors, known as braffos, were given authority by the Portuguese, and migration from the interior to coastal regions increased. The cultivation of maize and cassava, first introduced to the region by the Portuguese through trans-Atlantic trade, flourished in the Gold Coast and became dietary staples throughout West Africa. Further, Portuguese contact and activity along

352-450: A Navy Sonic Depth Finder to draw a continuous map across the bed of the Atlantic. This involved little guesswork because the idea of sonar is straightforward with pulses being sent from the vessel, which bounce off the ocean floor, then return to the vessel. The deep ocean floor is thought to be fairly flat with occasional deeps, abyssal plains , trenches , seamounts , basins , plateaus , canyons , and some guyots . Various shelves along

440-721: A branch of the Gulf Stream which flows northward from the Grand Banks ; and the Subpolar Front , an extension of the North Atlantic Current, a wide, vaguely defined region separating the subtropical gyre from the subpolar gyre. This system of currents transports warm water into the North Atlantic, without which temperatures in the North Atlantic and Europe would plunge dramatically. North of

528-552: A consolidation of relationships between the Donatários and their vassals. This subjective process usually involved close associations with the royal family or confidants of the Crown: a feudal meritocracy of vassals. This could result from rendering service during the overseas expansion or resulting from some heroism that may have been rewarded with a title. The monarch surrounded himself with "trustworthy" men who were existed within

616-515: A native translator, Caramansa reacted skeptically to the proposition, as several African homes would have to be destroyed for construction on the castle to begin. After the Portuguese threatened violence, Caramansa met Portuguese demands. However, he prohibited the use of sacred local rock, known to the native Elminans as Kokobo, and forbid the Portuguese from accessing the natives’ freshwater supply. Portuguese settlers, defying Caramansa's demands, mined Kokobo rock for construction purposes. Doing so upset

704-416: A weak Intertropical Convergence Zone , South Atlantic tropical cyclones are rare. The Atlantic Ocean is underlain mostly by dense mafic oceanic crust made up of basalt and gabbro and overlain by fine clay, silt and siliceous ooze on the abyssal plain. The continental margins and continental shelf mark lower density, but greater thickness felsic continental rock that is often much older than that of

792-477: A web of relationships, forming a restricted circle of individuals. In some cases precedents were superseded in favor of people they could trust, including setting aside the laws of male inheritance in favor of a daughter, for example (as with the case of the daughter of Jácome de Bruges ). Yet, most had to prove themselves, as was the case with Álvaro de Ornelas (captain of Pico), who lost his captaincy due to "inefficiency" in its settlement. The captaincy system

880-621: Is a complex of four water masses, two that form by deep convection in the open ocean – classical and upper Labrador sea water – and two that form from the inflow of dense water across the Greenland-Iceland-Scotland sill – Denmark Strait and Iceland-Scotland overflow water. Along its path across Earth the composition of the NADW is affected by other water masses, especially Antarctic bottom water and Mediterranean overflow water. The NADW

968-467: Is fed by a flow of warm shallow water into the northern North Atlantic which is responsible for the anomalous warm climate in Europe. Changes in the formation of NADW have been linked to global climate changes in the past. Since human-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

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1056-498: Is found off the eastern coast of Canada. Surface water temperatures, which vary with latitude, current systems, and season and reflect the latitudinal distribution of solar energy, range from below −2 °C (28 °F) to over 30 °C (86 °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 7–8 °C (13–14 °F). From October to June

1144-575: Is interrupted by larger transform faults at two places: the Romanche Trench near the Equator and the Gibbs fracture zone at 53°N . The MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other. The MAR rises 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and its rift valley is the divergent boundary between

1232-854: Is intersected by two perpendicular ridges: the Azores–Gibraltar Transform Fault , the boundary between the Nubian and Eurasian plates , intersects the MAR at the Azores triple junction , on either side of the Azores microplate, near the 40°N . A much vaguer, nameless boundary, between the North American and South American plates, intersects the MAR near or just north of the Fifteen-Twenty fracture zone , approximately at 16°N . In

1320-729: Is now northern and central Brazil. The formation of the Central American Isthmus closed the Central American Seaway at the end of the Pliocene 2.8 Ma ago. The formation of the isthmus resulted in the migration and extinction of many land-living animals, known as the Great American Interchange , but the closure of the seaway resulted in a "Great American Schism" as it affected ocean currents, salinity, and temperatures in both

1408-794: Is now the Carpathian region, that were similar to the Sargasso Sea. It is possible that the population in the Sargasso Sea migrated to the Atlantic as the Tethys closed at the end of the Miocene around 17 Ma. The origin of the Sargasso fauna and flora remained enigmatic for centuries. The fossils found in the Carpathians in the mid-20th century often called the "quasi-Sargasso assemblage", finally showed that this assemblage originated in

1496-690: Is the second-largest of the world's five oceanic divisions , with an area of about 85,133,000 km (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery , it was known for separating the New World of the Americas ( North America and South America ) from the Old World of Afro-Eurasia ( Africa , Asia , and Europe ). Through its separation of Afro-Eurasia from

1584-472: The Age of Discovery , the Atlantic was also known to English cartographers as the Great Western Ocean . The pond is a term often used by British and American speakers in reference to the northern Atlantic Ocean, as a form of meiosis , or ironic understatement. It is used mostly when referring to events or circumstances "on this side of the pond" or "on the other side of the pond" or "across

1672-564: The Carpathian Basin from where it migrated over Sicily to the central Atlantic where it evolved into modern species of the Sargasso Sea. The location of the spawning ground for European eels remained unknown for decades . In the early 19th century it was discovered that the southern Sargasso Sea is the spawning ground for both the European and American eel and that the former migrate more than 5,000 km (3,100 mi) and

1760-474: The Icelandic Low produces frequent storms. Icebergs are common from early February to the end of July across the shipping lanes near the Grand Banks of Newfoundland . The ice season is longer in the polar regions, but there is little shipping in those areas. Hurricanes are a hazard in the western parts of the North Atlantic during the summer and autumn. Due to a consistently strong wind shear and

1848-684: The North American and Eurasian plates in the North Atlantic and the South American and African plates in the South Atlantic. The MAR produces basaltic volcanoes in Eyjafjallajökull , Iceland, and pillow lava on the ocean floor. 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. The MAR

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1936-616: The North Atlantic Drift is thought to have at least some influence on climate. For example, the Gulf Stream helps moderate winter temperatures along the coastline of southeastern North America, keeping it warmer in winter along the coast than inland areas. The Gulf Stream also keeps extreme temperatures from occurring on the Florida Peninsula. In the higher latitudes, the North Atlantic Drift, warms

2024-514: The North Atlantic oscillation , occurs. On average, the Atlantic is the saltiest major ocean; surface water salinity in the open ocean ranges from 33 to 37 parts per thousand (3.3–3.7%) by mass and varies with latitude and season. Evaporation, precipitation, river inflow and sea ice melting influence surface salinity values. Although the lowest salinity values are just north of the equator (because of heavy tropical rainfall), in general,

2112-555: The Scotia Sea , and other tributary water bodies. Including these marginal seas the coast line of the Atlantic measures 111,866 km (69,510 mi) compared to 135,663 km (84,297 mi) for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km (41,100,000 sq mi) or 23.5% of the global ocean and has a volume of 310,410,900 km (74,471,500 cu mi) or 23.3% of

2200-619: The Titan in Greek mythology , who supported the heavens and who later appeared as a frontispiece in medieval maps and also lent his name to modern atlases . On the other hand, to early Greek sailors and in ancient Greek mythological literature such as the Iliad and the Odyssey , this all-encompassing ocean was instead known as Oceanus , the gigantic river that encircled the world; in contrast to

2288-666: The United Kingdom . From the 16th to 19th centuries, the Atlantic Ocean was the center of both an eponymous slave trade and the Columbian exchange while occasionally hosting naval battles. Such naval battles, as well as growing trade from regional American powers like the United States and Brazil , both increased in degree during the early 20th century, and while no major military conflicts have taken place in

2376-638: The meridional overturning circulation (MOC), the northward heat transport of which is threatened by anthropogenic climate change. Large variations in the subpolar gyre on a decade-century scale, associated with the North Atlantic oscillation , are especially pronounced in Labrador Sea Water , the upper layers of the MOC. The South Atlantic is dominated by the anti-cyclonic southern subtropical gyre. The South Atlantic Central Water originates in this gyre, while Antarctic Intermediate Water originates in

2464-458: The thermocline of the subtropical gyre. The Sargasso Sea in the western North Atlantic can be defined as the area where two species of Sargassum ( S. fluitans and natans ) float, an area 4,000 km (2,500 mi) wide and encircled by the Gulf Stream , North Atlantic Drift , and North Equatorial Current . This population of seaweed probably originated from Tertiary ancestors on

2552-578: 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

2640-618: The 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean. The Atlantic has irregular coasts indented by numerous bays, gulfs and seas. 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

2728-485: The 1960s and CFCs . 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. In the North Atlantic, surface circulation is dominated by three inter-connected currents: the Gulf Stream which flows north-east from the North American coast at Cape Hatteras ; the North Atlantic Current ,

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2816-578: The Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse were the first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus' expedition ushered in an age of exploration and colonization of the Americas by European powers , most notably Portugal , Spain , France , and

2904-516: The Asante and Denkyira regions of modern-day Ghana and became the dominant export from the colony along with, to a lesser extent, ivory. Additionally, the inflow of foreign crops into the Gold Coast region globalized the region's agricultural practices and output, introducing sugar, maize, guava, sweet potatoes, coconut, yams, and cassava to the African agricultural landscape. Further, the dominance of

2992-453: The Atlantic and Pacific. Marine organisms on both sides of the isthmus became isolated and either diverged or went extinct. Donatary captain A donatary captain was a Portuguese colonial official to whom the Crown granted jurisdiction, rights, and revenues over some colonial territory. The recipients of these grants were called donatários (donataries), because they had been given

3080-537: The Atlantic are wide off Newfoundland, southernmost South America, and northeastern Europe. In the western Atlantic carbonate platforms dominate large areas, for example, the Blake Plateau and Bermuda Rise . The Atlantic is surrounded by passive margins except at a few locations where active margins form deep trenches : the Puerto Rico Trench (8,376 m or 27,480 ft maximum depth) in

3168-625: The Atlantic include the Challenger expedition and the German Meteor expedition ; as of 2001 , Columbia University 's Lamont–Doherty Earth Observatory and the United States Navy Hydrographic Office conduct research on the ocean. The MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2,000 m (6,600 ft) along most of its length, but

3256-403: The Atlantic north of the equator. The coldest zones are in high latitudes, with the coldest regions corresponding to the areas covered by sea ice. Ocean currents influence the climate by transporting warm and cold waters to other regions. The winds that are cooled or warmed when blowing over these currents influence adjacent land areas. The Gulf Stream and its northern extension towards Europe,

3344-589: The Atlantic recently, the ocean remains a core component of trade around the world. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and the Americas to the west. As one component of the interconnected World Ocean , it is connected in the north to the Arctic Ocean , to the Pacific Ocean in the southwest, the Indian Ocean in

3432-469: The Atlantic sea ' , etym . ' Sea of Atlas ' ) and in The Histories of Herodotus around 450 BC (Hdt. 1.202.4): Atlantis thalassa (Ancient Greek: Ἀτλαντὶς θάλασσα , ' Sea of Atlas ' or ' the Atlantic sea ' ) where the name refers to "the sea beyond the pillars of Heracles " which is said to be part of the sea that surrounds all land. In these uses, the name refers to Atlas ,

3520-633: The Bahamas, while coarse river outwash sands and silt are common in shallow shelf areas like the Georges Bank . Coarse sand, boulders, and rocks were transported into some areas, such as off the coast of Nova Scotia or the Gulf of Maine during the Pleistocene ice ages. The break-up of Pangaea began in the central Atlantic, between North America and Northwest Africa, where rift basins opened during

3608-686: The Dutch were expelled from the area in what became known as the Battle of Elmina (1625) . In August of 1637, the Dutch West India Company again targeted Elmina, which they saw as both the seat of Portuguese power in the Gulf of Guinea and a potential foothold into the African slave trade . To aid in the conflict, known as the second Battle of Elmina (1637) , the Dutch encouraged members of

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3696-463: The Elmina, Komenda, and Efutu states to turn against the Portuguese. After gaining some local support, the Dutch were better equipped to take on the opposing Portuguese forces and succeeded in capturing a hill facing the fort of Elmina. After enduring days of cannon fire, the Portuguese conceded, and Elmina castle officially came under Dutch control on August 29, 1637. Without their stronghold in Elmina,

3784-516: The European shores of the former Tethys Ocean and has, if so, maintained itself by vegetative growth , floating in the ocean for millions of years. Other species endemic to the Sargasso Sea include the sargassum fish , a predator with algae-like appendages which hovers motionless among the Sargassum . Fossils of similar fishes have been found in fossil bays of the former Tethys Ocean, in what

3872-519: The Gold Coast extended from an area near modern-day New Town , Ghana, in the west to the historic settlement of Adda (near modern-day Denu , Ghana) in the east. Other European nations conducting trade in the Gulf, including the English and Dutch, offered lower-priced commodities than the Portuguese, driving many Africans to accept the risk of Portuguese retaliation in order to yield a larger profit from trade. Competition with European powers coupled with

3960-1050: The Gold Coast integrated the region into the global economy. The larger trade volume in the region centralized the small, distinct states that existed prior to Portuguese contact into larger political entities. The advent of global trade in the Gold Coast also consolidated commercial activity in coastal cities, which connected inland African communities with European trade. 15th century 16th century 15th century 16th century 17th century 18th century 19th century 16th century 17th century 15th century 16th century Portuguese India 17th century Portuguese India 18th century Portuguese India 16th century 17th century 19th century Portuguese Macau 20th century Portuguese Macau 15th century [Atlantic islands] 16th century [Canada] 16th century 17th century 18th century 19th century Atlantic Ocean The Atlantic Ocean

4048-461: The Gulf. After generations of intimate contact with local African dialects, Portuguese creole emerged as an important language of trade along the Gulf Coast, second only to Portuguese itself. Further, interbreeding between Portuguese and Africans led to a sizable mixed-race population along the Gold Coast. Urbanization occurred around Elmina, spurred partly by Portuguese attempts to establish

4136-623: The Late Triassic and Early Jurassic. This period also saw the first stages of the uplift of the Atlas Mountains. The exact timing is controversial with estimates ranging from 200 to 170 Ma. 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

4224-468: The North Atlantic Gyre, the cyclonic North Atlantic Subpolar Gyre plays a key role in climate variability. It is governed by ocean currents from marginal seas and regional topography, rather than being steered by wind, both in the deep ocean and at sea level. The subpolar gyre forms an important part of the global thermohaline circulation . Its eastern portion includes eddying branches of the North Atlantic Current which transport warm, saline waters from

4312-439: The Portuguese trade route along the Gulf Coast in the sixteenth century led to Portuguese becoming the principal language of exchange in the Gulf of Guinea. The language has endured in the area despite the presence of other European powers in the Gulf after the colony was ceded in 1642. The internal African slave trade established by the Portuguese laid the groundwork for the vast networks of human trafficking that would flourish in

4400-553: The Portuguese were completely expelled from the region by 1642. Donatary captain (donatário, or Captain-major) was a designation given by the Portuguese Crown to an official tasked with overseeing colonial territory. The following is a list of the known donatary captaincies in São Jorge da Mina: The Portuguese imported slaves to Elmina throughout the sixteenth century, using them primarily to transport goods to and from interior African states, but also to exchange with local Elminans for gold. The main supply of Gold Coast slaves came from

4488-437: The South Atlantic, and the "Atmospheric Bridge", which evaporates subtropical Atlantic waters and exports it to the Pacific. The Atlantic Ocean consists of four major, upper water masses with distinct temperature and salinity. The Atlantic subarctic upper water in the northernmost North Atlantic is the source for subarctic intermediate water and North Atlantic intermediate water. North Atlantic central water can be divided into

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4576-412: The atmosphere over the oceans, keeping the British Isles and northwestern Europe mild and cloudy, and not severely cold in winter, like other locations at the same high latitude. The cold water currents contribute to heavy fog off the coast of eastern Canada (the Grand Banks of Newfoundland area) and Africa's northwestern coast. In general, winds transport moisture and air over land areas. Every winter,

4664-483: The best parcels of lands and be able to contract renters to the donatárias (lands of the Donatários), in the name of the crown. Many of the donatários were hereditary, with a few exceptions, referred in the Salic Laws ( Portuguese : Leis Sálicas ) of the time; these laws regulated all aspects of life, including crime, taxation, indemnity, and female inheritance. The Captains were less restricted to these conditions. Yet, many of these captains were selected as part of

4752-416: The captain-major was the channel by which the monarch could delegate his powers, with certain restrictions, under the responsibility of peoples he felt he could confide. The Donatário could administer, in the sovereign's name, the lands for which he was assigned, with all the regalia, rights, and obligations, with the exception of certain limits, including military authority over soldiers and detachments of

4840-402: The crown, or the administration of justice. The Captains were agents named by the Donatário, and after 1495, by the Crown, to a lifetime title that was passed down by the "legitimate male heirs". As administrators, the Captains enjoyed various judicial and economic privileges that provided an incentive to settle and develop their captaincies. They had the authority to administer sentences, with

4928-432: The decline of Portugal’s economic might in the early 1600s led to a waning of Portuguese influence in the Gold Coast region. Spurred by reports of the successful Portuguese gold trade in the Gulf of Guinea, Dutch forces began mobilizing against the Portuguese in an effort to wrest control of the region and monopolize the gold trade. In 1625, the Dutch West India Company initiated an attack on São Jorge da Mina, which stood as

5016-431: The east, the boundaries of the ocean proper are Europe: the Strait of Gibraltar (where it connects with the Mediterranean Sea  – one of its marginal seas  – and, in turn, the Black Sea , both of which also touch upon Asia) and Africa. In the southeast, the Atlantic merges into the Indian Ocean. The 20° East meridian , running south from Cape Agulhas to Antarctica defines its border. In

5104-544: The eastern and western North Atlantic central water since the western part is strongly affected by the Gulf Stream and therefore the upper layer is closer to underlying fresher subpolar intermediate water. The eastern water is saltier because of its proximity to Mediterranean water. North Atlantic central water flows into South Atlantic central water at 15°N . There are five intermediate waters: four low-salinity waters formed at subpolar latitudes and one high-salinity formed through evaporation. Arctic intermediate water flows from

5192-400: The enclosed seas well known to the Greeks: the Mediterranean and the Black Sea. In contrast, the term "Atlantic" originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the West African coast. The term " Aethiopian Ocean ", derived from Ancient Ethiopia , was applied to the southern Atlantic as late as the mid-19th century. During

5280-419: The exception of those involving penalties of death or mutilation. Economically, they had the exclusive authority to mill, bake bread and sell salt, in addition to their entitlement to receive rent paid to the King for lands, fees and taxes due. In addition, they could receive a tithe (the tenth portion) paid to the captaincy directly. In addition to the regalia of office, the captains-major would hold title to

5368-413: The grant as a doação (donation) by the king, often as a reward for service. The term also applied as the rank title of the field officer that was in charge of a captaincy (group of companies) of the Ordenanças , the Portuguese territorial militia that existed from the 16th to the 19th centuries. Due to the impossibility of exercising direct control and sovereignty over overseas territories,

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5456-505: The island of São Miguel when it was discovered. This captaincy, which lasted from 1439 to 1461, was described in 1460 by Henry the Navigator in a letter to Cabral as Capitão por mim em minhas ilhas de Santa Maria e São Miguel dos Açores ( Captain for Me in My Islands of Santa Maria and São Miguel in the Azores ). The progressive discovery of the islands of the archipelago resulted in new captaincies; in total, there have been thirteen unique captaincies in Azores since their discovery: Such

5544-421: The issues of their masters. The following is an incomplete list of some of the captaincies and their first Donatary-Captains: There were three captaincies in the archipelago of Madeira , associated with the three principal discoverers of the islands: Following their discovery, Gonçalo Velho Cabral became the first Donatary-Captain of the islands, beginning with the island of Santa Maria, but later including

5632-454: The latter 2,000 km (1,200 mi). Ocean currents such as the Gulf Stream transport eel larvae from the Sargasso Sea to foraging areas in North America, Europe, and northern Africa. Recent but disputed research suggests that eels possibly use Earth's magnetic field to navigate through the ocean both as larvae and as adults. The climate is influenced by the temperatures of the surface waters and water currents as well as winds. Because of

5720-448: The leaders of interior states, including to the Eguafo state to which Elmina belonged. Their strategy along the coast, however, entailed using force against Africans to prevent them from trading with European competitors. Portuguese violence along the coast soured their relations with neighboring African states; as such, the Portuguese lacked sufficient manpower to enforce their rule across the entire Gulf of Guinea. Portuguese influence along

5808-474: The limits of the oceans and seas in 1953, but some of these definitions have been revised since then and some are not recognized by various authorities, institutions, and countries, for example the CIA World Factbook . Correspondingly, the extent and number of oceans and seas vary. 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 . To

5896-405: The local population, yet conflict was avoided after the Portuguese bestowed gifts upon the native Elminans. Once constructed, Elmina Castle represented the first major European construction in sub-Saharn Africa and is currently recognized as a UNESCO World Heritage Site . In order to establish good trade relationships with neighboring African nations, the Portuguese frequently extended gifts to

5984-429: The lowest values are in the high latitudes and along coasts where large rivers enter. Maximum salinity values occur at about 25° north and south , in subtropical regions with low rainfall and high evaporation. The high surface salinity in the Atlantic, on which the Atlantic thermohaline circulation is dependent, is maintained by two processes: the Agulhas Leakage/Rings , which brings salty Indian Ocean waters into

6072-454: The margins of the continents constitute about 11% of the bottom topography with few deep channels cut across the continental rise. The mean depth between 60°N and 60°S is 3,730 m (12,240 ft), or close to the average for the global ocean, with a modal depth between 4,000 and 5,000 m (13,000 and 16,000 ft). In the South Atlantic the Walvis Ridge and Rio Grande Rise form barriers to ocean currents. The Laurentian Abyss

6160-407: The maximum depth, the Milwaukee Deep in the Puerto Rico Trench , is 8,376 m (27,480 ft). Top large seas: The bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge (MAR). It runs from 87°N or 300 km (190 mi) south of the North Pole to the subantarctic Bouvet Island at 54°S . Expeditions to explore the bathymertry of

6248-510: 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 . Theoliitic dikes , sills , and lava flows from the CAMP eruption at 200 Ma have been found in West Africa, eastern North America, and northern South America. The extent of the volcanism has been estimated to 4.5 × 10  km (1.7 × 10  sq mi) of which 2.5 × 10  km (9.7 × 10  sq mi) covered what

6336-571: The north to become the source for North Atlantic deep water, south of the Greenland-Scotland sill. These two intermediate waters have different salinity in the western and eastern basins. The wide range of salinities in the North Atlantic is caused by the asymmetry of the northern subtropical gyre and a large number of contributions from a wide range of sources: Labrador Sea, Norwegian-Greenland Sea, Mediterranean, and South Atlantic Intermediate Water. The North Atlantic deep water (NADW)

6424-425: The ocean's great capacity to store and release heat, maritime climates are more moderate and have less extreme seasonal variations than inland climates. Precipitation can be approximated from coastal weather data and air temperature from water temperatures. The oceans are the major source of atmospheric moisture that is obtained through evaporation. Climatic zones vary with latitude; the warmest zones stretch across

6512-565: The outlines of the coasts of the Old and the New Worlds. The remainder of the ridge was discovered in the 1920s by the German Meteor expedition using echo-sounding equipment. The exploration of the MAR in the 1950s led to the general acceptance of seafloor spreading and plate tectonics . Most of the MAR runs under water but where it reaches the surfaces it has produced volcanic islands. While nine of these have collectively been nominated

6600-595: The pond", rather than to discuss the ocean itself. The term dates to 1640, first appearing in print in a pamphlet released during the reign of Charles I , and reproduced in 1869 in Nehemiah Wallington 's Historical Notices of Events Occurring Chiefly in The Reign of Charles I , where "great Pond" is used in reference to the Atlantic Ocean by Francis Windebank , Charles I's Secretary of State . The International Hydrographic Organization (IHO) defined

6688-582: The region during the centuries to come, as the Dutch and, later, the British capitalized on pre-established trade routes during the Atlantic slave trade . Further, the shipping might of the Portuguese encouraged new, long-distance river trading amidst West African states, and the volume of trade along the Gulf of Guinea increased as a result of Portuguese presence. Boatbuilding became an important craft that accompanied an increase in coastal trade and seamanship in

6776-438: The seafloor. The oldest oceanic crust in the Atlantic is up to 145 million years and is situated off the west coast of Africa and the east coast of North America, or on either side of the South Atlantic. In many places, the continental shelf and continental slope are covered in thick sedimentary layers. For instance, on the North American side of the ocean, large carbonate deposits formed in warm shallow waters such as Florida and

6864-422: The site of construction for Elmina Castle to maximize defensibility. A nobleman named Diogo de Azambuja was appointed by the Portuguese king, John II , to construct the coastal fortress. To maintain peace with the native peoples of Elmina, Azambuja entered into negotiations with the native leader Caramansa over their plans to construct Elmina Castle. In a discussion facilitated by a Portuguese merchant and aided by

6952-536: The southeast, and the Southern Ocean in the south. Other definitions describe the Atlantic as extending southward to Antarctica . The Atlantic Ocean is divided in two parts, the northern and southern Atlantic, by the Equator . The oldest known mentions of an "Atlantic" sea come from Stesichorus around mid-sixth century BC (Sch. A. R. 1. 211): Atlantikôi pelágei (Ancient Greek: Ἀτλαντικῷ πελάγει , '

7040-551: The subtropics to the northeastern Atlantic. 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 . A third of this water becomes part of the deep portion of the North Atlantic Deep Water (NADW). The NADW, in turn, feeds

7128-421: The surface is usually covered with sea ice in the Labrador Sea , Denmark Strait , and Baltic Sea. The Coriolis effect circulates North Atlantic water in a clockwise direction, whereas South Atlantic water circulates counter-clockwise. The south tides in the Atlantic Ocean are semi-diurnal; that is, two high tides occur every 24 lunar hours. In latitudes above 40° North some east–west oscillation, known as

7216-480: The total volume of the Earth's oceans. Excluding its marginal seas, the Atlantic covers 81,760,000 km (31,570,000 sq mi) and has a volume of 305,811,900 km (73,368,200 cu mi). The North Atlantic covers 41,490,000 km (16,020,000 sq mi) (11.5%) and the South Atlantic 40,270,000 km (15,550,000 sq mi) (11.1%). The average depth is 3,646 m (11,962 ft) and

7304-494: The trade route between Benin and Elmina, which also supplied the Portuguese with important commodities such as cotton, cloth, and beads. The slave trade was later expanded to encompass the Niger River delta and the island of São Tome . Cloth, linens , beads, copper and brass pots, pans, bracelets, and slaves were all used as bartering tools to obtain gold from the native merchants of Elmina. Elmina's gold originated from

7392-678: The trading hub for the Portuguese in West Africa. The Dutch fleet was made up of the combined forces of Captain Jan Dircksz Lam and the remaining ships from Boudewijn Hendricksz’s failed venture in Salvador against the Spanish. On October 25, 1625, the Dutch were ambushed by Portuguese forces and their African allies, which were persuaded to join the fight after the Portuguese promised them compensation. After incurring heavy losses,

7480-581: The upper layers of the circumpolar region, near the Drake Passage and the Falkland Islands. Both these currents receive some contribution from the Indian Ocean. On the African east coast, the small cyclonic Angola Gyre lies embedded in the large subtropical gyre. The southern subtropical gyre is partly masked by a wind-induced Ekman layer . The residence time of the gyre is 4.4–8.5 years. North Atlantic Deep Water flows southward below

7568-424: The western Atlantic and South Sandwich Trench (8,264 m or 27,113 ft) in the South Atlantic. There are numerous submarine canyons off northeastern North America, western Europe, and northwestern Africa. Some of these canyons extend along the continental rises and farther into the abyssal plains as deep-sea channels. In 1922, a historic moment in cartography and oceanography occurred. The USS Stewart used

7656-621: Was built on confidence and good faith between the captain and donatário , owing to the distance between each. This weakened the Donatário 's control over the officials, resulting in a disparity between actual and perceived function. Some were either incompetent in their roles, power-hungry or just absent. In some cases the inhabitants of certain possessions were often subject to irregularities resulting from judicial or fiscal issues. Some captains appointed overseers, ouvidores ( auditors ) to represent them who were unqualified to respond to

7744-460: Was erected near a populated African town which was also called Elmina. The other major Portuguese settlements on the Gold Coast included the following: The Portuguese decision to construct the fortress at Elmina was influenced by a pre-established trade system between native Elminans and Portuguese merchants in the area. A natural peninsula, enclosed by the Atlantic and the Benya river, was chosen as

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