Practical work in geography (for the textbook A. A

ATLANTIC OCEAN (Latin name Mare Atlanticum, Greek? Τλαντ? Σ - meant the space between the Strait of Gibraltar and the Canary Islands, the whole ocean was called Oceanus Occidental is - Western Ocean), the second largest ocean on Earth (after the Pacific Ocean), part of the World Ocean. The modern name first appeared in 1507 on the map of the Lorraine cartographer M. Waldseemüller.

Physical and geographical sketch. General information ... In the north, the border of the Atlantic Ocean with the Arctic Ocean basin runs along the eastern entrance of the Hudson Strait, then through the Davis Strait and along the coast of Greenland to Cape Brewster, through the Danish Strait to Cape Reidinupur on Iceland, along its coast to Cape Gerpier (Terpir), then to the Faroe Islands, then to the Shetland Islands and 61 ° north latitude to the coast of the Scandinavian Peninsula. In the east Atlantic Ocean limited by the shores of Europe and Africa, in the west - by the shores North America and South America. The border of the Atlantic Ocean with the Indian Ocean is drawn along a line passing from Cape Agulhas along the meridian 20 ° east longitude to the coast of Antarctica. The border with the Pacific Ocean is drawn from Cape Horn along the meridian 68 ° 04 'West longitude or along the shortest distance from South America to the Antarctic Peninsula through the Drake Passage, from Oste Island to Cape Sternek. The South Atlantic Ocean is sometimes called the Atlantic Sector of the Southern Ocean, drawing the boundary along the subantarctic convergence zone (approximately 40 ° S latitude). In some works, the division of the Atlantic Ocean into the North and South Atlantic oceans is proposed, but it is more customary to consider it as a single ocean. The Atlantic Ocean is the most biologically productive of the oceans. It contains the longest underwater oceanic ridge - the Mid-Atlantic ridge, the only sea that does not have solid shores, limited by currents - the Sargasso Sea; Bay of Fundy with the highest tidal wave; the Black Sea with a unique hydrogen sulfide layer belongs to the Atlantic Ocean basin.

The Atlantic Ocean stretches from north to south for almost 15 thousand km, its smallest width is about 2830 km in the equatorial part, the largest is 6700 km (along the parallel of 30 ° north latitude). The area of the Atlantic Ocean with seas, bays and straits is 91.66 million km 2, without them - 76.97 million km 2. The volume of water is 329.66 million km 3, without seas, bays and straits - 300.19 million km 3. The average depth is 3597 m, the greatest is 8742 m (the trench of Puerto Rico). The most easily accessible ocean shelf zone (with depths of up to 200 m) occupies about 5% of its area (or 8.6% if we take into account seas, bays and straits), its area is larger than in the Indian and Pacific Oceans, and much less than in the Arctic Ocean. Areas with depths from 200 m to 3000 m (continental slope zone) occupy 16.3% of the ocean area, or 20.7% taking into account the seas and bays, more than 70% - the ocean floor (abyssal zone). See the map.

Seas... In the basin of the Atlantic Ocean there are numerous seas, which are divided into: the internal ones - the Baltic, Azov, Black, Marmara and Mediterranean (in the latter, in turn, the seas are distinguished: Adriatic, Alboran, Balearic, Ionian, Cypriot, Ligurian, Tyrrhenian, Aegean) ; inter-island - the Irish and inland seas of the west coast of Scotland; marginal - Labrador, Severnoye, Sargassovo, Caribbean, Scotia (Scotia), Weddell, Lazareva, western part of Riiser-Larsen (see separate articles on the seas). The largest bays of the ocean: Biscay, Bristol, Guinea, Mexican, Maine, Saint Lawrence.

Islands... Unlike other oceans, the Atlantic Ocean has few seamounts, guyots and coral reefs, and there are no coastal reefs. The total area of the islands of the Atlantic Ocean is about 1070 thousand km 2. The main groups of islands are located on the outskirts of the continents: British (Great Britain, Ireland, etc.) - the largest in area, Greater Antilles (Cuba, Haiti, Jamaica, etc.), Newfoundland, Iceland, the Tierra del Fuego archipelago (Tierra del Fuego, Oste, Navarino ), Marajo, Sicily, Sardinia, Lesser Antilles, Falkland (Malvinas), Bahamas, etc. In the open ocean there are small islands: Azores, Sao Paulo, Ascension, Tristan da Cunha, Bouvet (on the Mid-Atlantic ridge) and dr.

The shores... The coastline in the North Atlantic Ocean is heavily indented (see also the article Shore), almost all large inland seas and bays are located here, in the South Atlantic, the shores are weakly indented. The shores of Greenland, Iceland and the coast of Norway are predominantly of tectonic-glacial dissection of the fjord and fiard types. Farther south, in Belgium, they give way to sandy shallow shores. The Flanders coast is mainly of artificial origin (coastal dams, polders, canals, etc.). The shores of the island of Great Britain and the island of Ireland are abrasion-coiled, high limestone cliffs alternate with sandy beaches and muddy drylands. On the Cherbourg peninsula there are rocky shores, sandy and gravel beaches. The northern coast of the Iberian Peninsula is made of rock, to the south, off the coast of Portugal, sandy beaches prevail, often fencing off lagoons. Sandy beaches also border the shores of Western Sahara and Mauritania. To the south of Cape Zelyoniy there are leveled abrasion-bay shores with mangrove thickets. The western section of Côte d'Ivoire has an accumulative

coast with rocky capes. To the southeast, to the vast delta of the Niger River, there is an accumulative bank with a significant number of spits and lagoons. In southwestern Africa, there are accumulative, less often abrasion-bay shores with extensive sandy beaches. The shores of southern Africa of the abrasion-bay type are composed of hard crystalline rocks. The shores of Arctic Canada are abrasive, with high cliffs, glacial deposits and limestones. In eastern Canada and northern St Lawrence Bay, there are intensely eroded limestone and sandstone cliffs. In the west and south of the Gulf of St. Lawrence, there are wide beaches. On the shores of the Canadian provinces of Nova Scotia, Quebec, Newfoundland - outcrops of hard crystalline rocks. From about 40 ° north latitude to Cape Canaveral in the USA (Florida) there is an alternation of leveled accumulative and abrasion types of shores, composed of loose rocks. The Gulf Coast is low-lying, fringed by Florida mangroves, Texas sand barriers and Louisiana delta shores. On the Yucatan Peninsula - cemented beach sediments, to the west of the peninsula - an alluvial-marine plain with coastal ramparts. On the Caribbean coast, abrasion and accumulation areas alternate with mangrove swamps, coastal barriers and sandy beaches. To the south of 10 ° north latitude, accumulative banks are widespread, composed of material carried out from the mouth of the Amazon River and other rivers. In the northeast of Brazil, there is a sandy coast with mangrove thickets, interrupted by river estuaries. From Cape Kalkanyar to 30 ° South latitude there is a high abrasion-type coastline. To the south (off the coast of Uruguay) there is an abrasion-type coast, composed of clays, loesses and sand and gravel deposits. In Patagonia, the shores are represented by high (up to 200 m) cliffs with loose sediments. The shores of Antarctica are 90% composed of ice and belong to the ice and thermal abrasion type.

Bottom relief... At the bottom of the Atlantic Ocean, the following large geomorphological provinces are distinguished: the underwater margin of the continents (shelf and continental slope), the ocean floor (deep-sea basins, abyssal plains, zones of abyssal hills, uplifts, mountains, deep-sea trenches), mid-ocean ridges.

The boundary of the continental shelf (shelf) of the Atlantic Ocean runs on average at depths of 100-200 m, its position can vary from 40-70 m (in the area of Cape Hatteras and the Florida Peninsula) to 300-350 m (Weddell Cape). The shelf width ranges from 15-30 km (northeastern Brazil, Iberian Peninsula) to several hundred km (North Sea, Gulf of Mexico, Bank of Newfoundland). In high latitudes, the relief of the shelf is complex and bears traces of glacial impact. Numerous uplifts (banks) are separated by longitudinal and transverse valleys or trenches. Off the coast of Antarctica, ice shelves are located on the shelf. At low latitudes, the shelf surface is more leveled, especially in the zones of terrigenous material removal by rivers. It is crossed by transverse valleys, often turning into canyons of the continental slope.

The slope of the continental slope of the ocean averages 1-2 ° and varies from 1 ° (areas of Gibraltar, Shetland Islands, parts of the African coast, etc.) to 15-20 ° off the coast of France and the Bahamas. The height of the continental slope varies from 0.9-1.7 km near the Shetland Islands and Ireland to 7-8 km in the Bahamas and the Puerto Rico trench. The active margins are characterized by high seismicity. The surface of the slope is in places dissected by steps, scarps and terraces of tectonic and accumulative origin and longitudinal canyons. At the foot of the continental slope there are often gentle hills up to 300 m high and shallow underwater valleys.

In the middle part of the floor of the Atlantic Ocean is the largest mountain system of the Mid-Atlantic Ridge. It stretches from Iceland to Bouvet Island for 18,000 km. The width of the ridge ranges from several hundred to 1000 km. The ridge runs close to the midline of the ocean, dividing it into eastern and western parts. On both sides of the ridge, there are deep-water basins separated by bottom uplifts. In the western part of the Atlantic Ocean, the following basins are distinguished from north to south: Labrador (with depths of 3000-4000 m); Newfoundland (4200-5000 m); The North American Basin (5000-7000 m), which includes the Som, Hatteras and Nares abyssal plains; Guiana (4500-5000 m) with the plains of Demerara and Ceara; Brazilian Basin (5000-5500 m) with the Abyssal Plain of Pernambuco; Argentinian (5000-6000 m). In the eastern part of the Atlantic Ocean there are basins: Western European (up to 5000 m), Iberian (5200-5800 m), Canary (over 6000 m), Cape Verde (up to 6000 m), Sierra Leone (about 5000 m), Guinea (over 5000 m) ), Angolan (up to 6000 m), Cape (over 5000 m) with the abyssal plains of the same name. In the south, there is the African-Antarctic Basin with the Weddell Abyssal Plain. The bottom of the deep-water basins at the foot of the Mid-Atlantic Ridge is occupied by a zone of abyssal hills. The basins are separated by the uplifts of Bermuda, Rio Grande, Rockall, Sierra Leone, and others, and by the Kitovy, Newfoundland, and other ridges.

Seamounts (isolated conical elevations with a height of 1000 m and more) on the floor of the Atlantic Ocean are concentrated mainly in the zone of the Mid-Atlantic Ridge. In the deep-water part, large groups of seamounts are found north of Bermuda, in the Gibraltar sector, at the northeastern bulge of South America, in the Gulf of Guinea and west of South Africa.

Deep-sea trenches Puerto Rico, Cayman (7090 m), South Sandwich trench (8264 m) are located at the island arcs. The Romansh Trench (7856 m) is a large fault. The steepness of the slopes of the deep-water trenches is from 11 ° to 20 °. The bottom of the gutters is flat, leveled by accumulation processes.

Geological structure. The Atlantic Ocean emerged as a result of the collapse of the late Paleozoic supercontinent Pangea during the Jurassic time. It is characterized by a sharp predominance of passive outskirts. The Atlantic Ocean is bordered by adjacent continents along transform faults south of Newfoundland, along the northern coast of the Gulf of Guinea, along the Falklands Submarine Plateau and the Agulhas Plateau in the southern part of the ocean. Active margins are observed in some areas (in the area of the Lesser Antilles arc and the arc of the South Sandwich Islands), where subsidence occurs with subduction (subduction) of the Atlantic Ocean crust. The limited extent of the Gibraltar subduction zone has been identified in the Gulf of Cadiz.

In the Mid-Atlantic Ridge, the bottom is spreading (spreading) and the formation of the oceanic crust at a rate of up to 2 cm per year. High seismic and volcanic activity is characteristic. To the north of the Mid-Atlantic Ridge, paleospreading ridges branch off into the Labrador Sea and the Bay of Biscay. In the axial part of the ridge, there is a pronounced rift valley, which is absent in the extreme south and in most of the Reykjanes ridge. Within its limits are volcanic uplifts, frozen lava lakes, basaltic lava flows in the form of pipes (pillubasalts). In the Central Atlantic, fields of metalliferous fluids have been discovered, many of which form hydrothermal edifices at the outlet (composed of sulfides, sulfates, and metal oxides); metal-bearing sediments have been established. At the foot of the slopes of the valley there are taluses and landslides, consisting of blocks and rubble of rocks of the oceanic crust (basalts, gabbros, peridotites). The age of the crust within the Oligocene ridge is modern. The Mid-Atlantic Ridge separates the zones of the western and eastern abyssal plains, where the oceanic basement is overlain by a sedimentary cover, the thickness of which increases towards the continental foothills to 10-13 km due to the appearance of more ancient horizons in the section and the influx of clastic material from the land. In the same direction, the age of the oceanic crust increases, reaching the Early Cretaceous (north of Florida in the Middle Jurassic). The abyssal plains are practically aseismic. The Mid-Atlantic Ridge is crossed by numerous transform faults extending to the adjacent abyssal plains. The thickening of such faults is observed in the equatorial zone (up to 12 by 1700 km). The largest transform faults (Vima, Sao Paulo, Romansh, etc.) are accompanied by deep incisions (grooves) on the ocean floor. They reveal the entire section of the oceanic crust and partly of the upper mantle; there are widespread protrusions (cold intrusions) of serpentinized peridotites, forming ridges elongated along the strike of the faults. Many transform faults are transoceanic, or main (demarcation) faults. The Atlantic Ocean contains the so-called intraplate uplifts, represented by submarine plateaus, aseismic ridges and islands. They have a thick oceanic crust and are mainly of volcanic origin. Many of them were formed as a result of the action of mantle jets (plumes); some arose at the intersection of the spreading ridge by large transform faults. Volcanic uplifts include: Iceland Island, Bouvet Island, Madeira Island, Canary Islands, Cape Verde, Azores, pair of Sierra and Sierra Leone uplifts, Rio Grande and Whale Ridge, Bermuda Uplift, Cameroon group of volcanoes, etc. In the Atlantic Ocean there are intraplate uplifts of non-volcanic nature, including the Rockall underwater plateau, separated from the British Isles by the trough of the same name. The plateau is a microcontinent that split off from Greenland in the Paleocene. Another microcontinent also split off from Greenland is the Hebrides Massif in northern Scotland. Submarine marginal plateaus off the coast of Newfoundland (Great Newfoundland, Flemish Cap) and off the coast of Portugal (Iberian) were cut off from the continents as a result of rifting in the late Jurassic - early Cretaceous.

The Atlantic Ocean is divided by transoceanic transform faults into segments with different opening times. From north to south, the Labrador-British, Newfoundland-Iberian, Central, Equatorial, Southern and Antarctic segments are distinguished. The opening of the Atlantic began in the early Jurassic (about 200 million years ago) from the Central Segment. In the Triassic - Early Jurassic, the spreading of the ocean floor was preceded by continental rifting, traces of which are recorded in the form of semi-grabens (see Graben) filled with detrital deposits on the American and North African margins of the ocean. In the late Jurassic - early Cretaceous, the Antarctic segment began to open. In the Early Cretaceous, spreading was experienced by the Southern Segment in the South Atlantic and the Newfoundland-Iberian Segment in the North Atlantic. Opening of the Labrador-British segment began at the end of the Early Cretaceous. At the end of the Late Cretaceous, the Labrador Basin Sea arose here as a result of spreading on the side axis, which continued until the Late Eocene. The North and South Atlantic united in the middle Cretaceous - Eocene during the formation of the Equatorial segment.

Bottom sediments... The thickness of the strata of modern bottom sediments ranges from several meters in the zone of the ridge of the Mid-Atlantic Ridge to 5-10 km in the zones of transverse faults (for example, in the Romanche trench) and at the foot of the continental slope. In deep-water basins, their thickness is from several tens to 1000 m. Over 67% of the ocean floor area (from Iceland in the north to 57-58 ° south latitude) is covered with calcareous deposits formed by the remains of shells of planktonic organisms (mainly foraminifera, coccolithophorids). Their composition varies from coarse sands (at depths of up to 200 m) to silts. At depths of more than 4500-4700 m, lime mud is replaced by polygenic and siliceous planktonic sediments. The former occupy about 28.5% of the ocean floor area, lining the bottoms of the basins, and are represented by deep-sea red oceanic clay (deep-sea clayey silts). These sediments contain a significant amount of manganese (0.2-5%) and iron (5-10%) and a very small amount of carbonate material and silicon (up to 10%). Siliceous planktonic sediments occupy about 6.7% of the ocean floor, of which diatom oozes (formed by the skeletons of diatoms) are the most widespread. They are common off the coast of Antarctica and on the shelf of Southwest Africa. Radiolarian oozes (formed by the skeletons of radiolarians) are found mainly in the Angola Basin. Terrigenous sediments of various compositions (gravel-pebble, sandy, clayey, etc.) are developed along the coast of the ocean, on the shelf and partly on the continental slopes. The composition and thickness of terrigenous sediments are determined by the bottom topography, the activity of the influx of solid material from the land and the mechanism of their transfer. Glacial precipitation carried by icebergs is widespread along the coast of Antarctica, Greenland, Newfoundland, and the Labrador Peninsula; are composed of poorly sorted detrital material with the inclusion of boulders, in to a greater extent in the south of the Atlantic Ocean. In the equatorial part, sediments (from coarse sand to silt) formed from pteropod shells are often found. Coral sediments (coral breccias, pebbles, sands and silts) are located in the Gulf of Mexico, the Caribbean and off the northeastern coast of Brazil; their maximum depth is 3500 meters. Volcanic sediments are developed near volcanic islands (Iceland, Azores, Canary, Cape Verde, etc.) and are represented by fragments of volcanic rocks, slag, pumice, volcanic ash. Modern chemogenic sediments are found in the Big Bahamas Bank, in the Florida-Bahamas, Antilles regions (chemogenic and chemogenic-biogenic carbonates). In the depressions of the North American, Brazilian, Cape Verde, ferromanganese nodules are found; their composition in the Atlantic Ocean: manganese (12.0-21.5%), iron (9.1-25.9%), titanium (up to 2.5%), nickel, cobalt and copper (tenths of a percent). Phosphorite nodules appear at depths of 200-400 m off the east coast of the United States and the northwest coast of Africa. Phosphorites are distributed along the eastern coast of the Atlantic Ocean - from the Iberian Peninsula to Cape Agulhas.

Climate... Due to the great length of the Atlantic Ocean, its waters are located in almost all natural climatic zones - from the subarctic in the north to the Antarctic in the south. From the north and south, the ocean is wide open to the influence of Arctic and Antarctic waters and ice. The lowest air temperature is observed in the polar regions. Over the coast of Greenland, temperatures can drop to -50 ° C, and in the southern Weddell Sea, temperatures of -32.3 ° C have been recorded. In the equatorial region, the air temperature is 24-29 ° C. The pressure field over the ocean is characterized by a successive change of stable large baric formations. Over the ice domes of Greenland and Antarctica there are anticyclones, in the temperate latitudes of the Northern and Southern Hemispheres (40-60 °) - cyclones, in lower latitudes - anticyclones, separated by a zone of low pressure at the equator. This baric structure supports steady eastward winds (trade winds) in tropical and equatorial latitudes, and strong westerly winds in temperate latitudes, which have been called "roaring forties" by seafarers. Strong winds are typical for the Bay of Biscay. In the equatorial region, the interaction of the northern and southern baric systems leads to frequent tropical cyclones (tropical hurricanes), the greatest activity of which is observed from July to November. The horizontal dimensions of tropical cyclones are up to several hundred kilometers. The wind speed in them is 30-100 m / s. They move, as a rule, from east to west at a speed of 15-20 km / h and reach their greatest strength over the Caribbean Sea and the Gulf of Mexico. In areas of low pressure in temperate and equatorial latitudes, precipitation often falls and strong clouds are observed. Thus, over 2000 mm of precipitation falls on the equator per year, in temperate latitudes - 1000-1500 mm. In areas of high pressure (subtropics and tropics), the amount of precipitation decreases to 500-250 mm per year, and in areas adjacent to the desert coast of Africa, and in the South Atlantic maximum - to 100 mm or less per year. In areas where warm and cold currents meet, fogs are frequent, for example, in the area of the Newfoundland Bank and in La Plata Bay.

Hydrological regime. Rivers and water balance. In the Atlantic Ocean basin, 19,860 km 3 of water is annually carried out by rivers, which is more than in any other ocean (about 45% of the total flow into the World Ocean). The largest rivers (with an annual discharge of over 200 km): Amazon, Mississippi (flows into the Gulf of Mexico), St. Lawrence River, Congo, Niger, Danube (flows into the Black Sea), Parana, Orinoco, Uruguay, Magdalena (flows into the Caribbean Sea) ). However, the balance of fresh water in the Atlantic Ocean is negative: evaporation from its surface (100-125 thousand km 3 / year) significantly exceeds atmospheric precipitation (74-93 thousand km 3 / year), river and groundwater runoff (21 thousand km 3 / year) and melting of ice and icebergs in the Arctic and Antarctic (about 3 thousand km 3 / year). The water balance deficit is made up for by the influx of water, mainly from the Pacific Ocean, 3470 thousand km 3 / year flows through the Drake Passage with the course of the Western Winds, and only 210 thousand km 3 / year leave the Atlantic Ocean to the Pacific Ocean. 260 thousand km 3 / year flows from the Arctic Ocean through numerous straits into the Atlantic Ocean, and 225 thousand km 3 / year of Atlantic waters flows back into the Arctic Ocean. The water balance with the Indian Ocean is negative, in Indian Ocean with the course of the Western Winds, 4976 thousand km 3 / year are carried out, and only 1692 thousand km 3 / year comes back with the Coastal Antarctic Current, deep and bottom waters.

Temperature regime... The average temperature of ocean waters as a whole is 4.04 ° С, and of surface waters 15.45 ° С. The distribution of water temperature on the surface is asymmetric relative to the equator. The strong influence of Antarctic waters leads to the fact that the surface waters of the Southern Hemisphere are almost 6 ° C colder than the North, the warmest waters of the open part of the ocean (thermal equator) are located between 5 and 10 ° N latitude, that is, they are displaced north of the geographic equator. The peculiarities of large-scale water circulation lead to the fact that the water temperature on the surface near the western coast of the ocean is approximately 5 ° C higher than that of the eastern one. The warmest water temperature (28-29 ° C) on the surface in the Caribbean Sea and the Gulf of Mexico in August, the lowest - off the coast of Greenland, Baffin Island, Labrador Peninsula and Antarctica, south of 60 °, where even in summer the water temperature does not rise above 0 ° C. The water temperature in the layer of the main thermocline (600-900 m) is about 8-9 ° C, deeper, in intermediate waters, it drops on average to 5.5 ° C (1.5-2 ° C in Antarctic intermediate waters). In deep waters, the average water temperature is 2.3 ° C, in bottom waters - 1.6 ° C. At the very bottom, the water temperature rises slightly due to the geothermal heat flux.

Salinity... The waters of the Atlantic Ocean contain about 1.1 · 10 16 tons of salts. Average salinity waters of the entire ocean 34.6 ‰, surface waters 35.3 ‰. The highest salinity (over 37.5 ‰) is observed on the surface in subtropical regions, where the evaporation of water from the surface exceeds its input with atmospheric precipitation, the lowest (6-20 ‰) in the mouths of large rivers flowing into the ocean. From subtropics to high latitudes, salinity on the surface decreases to 32-33 ‰ under the influence of precipitation, ice, river and surface runoff. In temperate and tropical regions, the maximum salinity values are on the surface, an intermediate minimum salinity is observed at depths of 600-800 m. The waters of the North Atlantic Ocean are characterized by a deep maximum salinity (more than 34.9 ‰), which is formed by highly saline Mediterranean waters. The deep waters of the Atlantic Ocean have a salinity of 34.7-35.1 ‰ and a temperature of 2-4 ° C, the bottom, occupying the deepest depressions of the ocean, 34.7-34.8 ‰ and 1.6 ° C, respectively.

Density... The density of water depends on temperature and salinity, and for the Atlantic Ocean, temperature is more important in the formation of the field of water density. The waters with the lowest density are located in the equatorial and tropical zones with high water temperatures and a strong influence of the runoff of such rivers as the Amazon, Niger, Congo, etc. (1021.0-1022.5 kg / m 3). In the southern part of the ocean, the density of surface waters increases to 1025.0-1027.7 kg / m 3, in the northern part - up to 1027.0-1027.8 kg / m 3. The density of the deep waters of the Atlantic Ocean is 1027.8-1027.9 kg / m 3.

Ice regime... In the North Atlantic Ocean, first-year ice forms mainly in the inland seas of temperate latitudes, perennial ice is carried out from the Arctic Ocean. The boundary of the distribution of ice cover in the North Atlantic Ocean changes significantly; in winter, pack ice can reach 50-55 ° N latitude in different years. There is no ice in summer. The boundary of the Antarctic perennial ice in winter runs at a distance of 1600-1800 km from the coast (approximately 55 ° South latitude), in summer (February - March) ice is found only in the coastal strip of Antarctica and in the Weddell Sea. The main suppliers of icebergs are the ice sheets and ice shelves of Greenland and Antarctica. The total mass of icebergs coming from Antarctic glaciers is estimated at 1.6 · 10 12 tons per year, their main source is the Filchner Ice Shelf in the Weddell Sea. Icebergs with a total mass of 0.2-0.3 x 10 12 tons per year come from the glaciers of the Arctic into the Atlantic Ocean, mainly from the Jacobshavn Glacier (in the area of Disko Island off the western coast of Greenland). The average lifespan of Arctic icebergs is about 4 years, Antarctic icebergs are slightly longer. The boundary of the distribution of icebergs in the northern part of the ocean is 40 ° north latitude, but in some cases they were observed up to 31 ° north latitude. In the southern part, the border runs at 40 ° S, in the central part of the ocean and at 35 ° S on the western and eastern periphery.

Currents... The water circulation of the Atlantic Ocean is subdivided into 8 quasi-stationary oceanic gyres located almost symmetrically relative to the equator. Tropical anticyclonic, tropical cyclonic, subtropical anticyclonic, subpolar cyclonic oceanic gyres are located from low to high latitudes in the Northern and Southern Hemispheres. Their boundaries, as a rule, are the main ocean currents... The warm current of the Gulf Stream begins at the Florida Peninsula. Taking in the waters of the warm Antilles Current and the Florida Current, the Gulf Stream is directed to the northeast and at high latitudes is divided into several branches; the most significant of them are the Irminger Current, which carries warm waters to the Davis Strait, the North Atlantic Current, and the Norwegian Current, which flows into the Norwegian Sea and further to the northeast, along the coast of the Scandinavian Peninsula. A cold Labrador Current emerges from the Davis Strait towards them, the waters of which can be traced off the coast of America to almost 30 ° north latitude. The cold East Greenland Current flows from the Danish Strait into the ocean. In the low latitudes of the Atlantic Ocean, warm North trade currents and South trade winds are directed from east to west, between them, at about 10 ° north latitude, from west to east there is an inter-trade countercurrent, which is active mainly in summer in the northern hemisphere. From the South trade winds, the Brazilian current is separated, which runs from the equator and up to 40 ° south latitude along the coast of America. The northern branch of the South Tradewinds forms the Guiana Current, which runs from south to northwest until it joins the waters of the North Tradewinds. Off the coast of Africa, from 20 ° north latitude to the equator, the warm Guinean Current passes; in summer, the Inter-trade countercurrent is connected to it. In the southern part, the Atlantic Ocean is crossed by the cold West Winds Current (Antarctic Circumpolar Current), which enters the Atlantic Ocean through the Drake Passage, descends to 40 ° S latitude and exits into the Indian Ocean south of Africa. It is separated from it by the Falkland Current, which runs along the coast of America almost to the mouth of the Parana River, and the Benguela Current, which runs along the coast of Africa almost to the equator. The cold Canary Current runs from north to south - from the shores of the Iberian Peninsula to the Cape Verde Islands, where it passes into the North Trade Winds.

Deep water circulation... The deep circulation and structure of the waters of the Atlantic Ocean are formed as a result of changes in their density during cooling of waters or in zones of mixing of waters of different origins, where the density increases as a result of mixing of waters with different salinity and temperature. Subsurface waters are formed in subtropical latitudes and occupy a layer with a depth of 100-150 m to 400-500 m, with a temperature of 10 to 22 ° C and a salinity of 34.8-36.0 ‰. Intermediate waters are formed in subpolar regions and are located at depths from 400-500 m to 1000-1500 m, with a temperature of 3 to 7 ° C and a salinity of 34.0-34.9 ‰. The circulation of subsurface and intermediate waters is generally anticyclonic in nature. Deep waters form in the high latitudes of the northern and southern parts of the ocean. The waters formed in the Antarctic region have the highest density and spread from south to north in the bottom layer, their temperature is from negative (in high southern latitudes) to 2.5 ° C, salinity is 34.64-34.89 ‰. Waters formed in high northern latitudes move from north to south in a layer from 1500 to 3500 m, the temperature of these waters is from 2.5 to 3 ° C, salinity is 34.71-34.99 ‰. In the 1970s, V.N. Stepanov and, later, V.S. The broker substantiated the scheme of planetary interoceanic transfer of energy and matter, called the "global conveyor" or "global thermohaline circulation of the World Ocean." According to this theory, relatively salty North Atlantic waters reach the coast of Antarctica, mix with supercooled shelf water and, passing through the Indian Ocean, end their journey in the North Pacific Ocean.

Tides and excitement... The tides in the Atlantic Ocean are predominantly semidiurnal. Tidal wave height: 0.2-0.6 m in the open ocean, a few centimeters in the Black Sea, 18 meters in the Bay of Fundy ( Northern part Gulf of Maine in North America) - the highest in the world. The height of wind waves depends on the speed, time of exposure and acceleration of the wind; during strong storms it can reach 17-18 m. Rarely enough (once every 15-20 years), waves with a height of 22-26 m were observed.

Flora and fauna... The great length of the Atlantic Ocean, a variety of climatic conditions, a significant influx of fresh water and large upwellings provide a variety of living conditions. In total, about 200 thousand species of plants and animals live in the ocean (of which there are about 15,000 species of fish, about 600 species of cephalopods, about 100 species of whales and pinnipeds). Life is very unevenly distributed in the ocean. There are three main types of zoning in the distribution of life in the ocean: latitudinal, or climatic, vertical and circumcontinental zoning. The density of life and its species diversity decrease with distance from the coast towards the open ocean and from the surface to deep waters. Species diversity also decreases from tropical latitudes to high ones.

Planktonic organisms (phytoplankton and zooplankton) are the basis of the food chain in the ocean, the bulk of them live in the upper zone of the ocean, where light penetrates. The greatest biomass of plankton is in high and temperate latitudes during spring-summer flowering (1-4 g / m 3). During the year, the biomass can change 10-100 times. The main species of phytoplankton are diatoms, zooplankton - copepods and euphausids (up to 90%), as well as bristle-mandibular, hydromedusa, comb jellies (in the north) and salps (in the south). In low latitudes, the plankton biomass varies from 0.001 g / m 3 in the centers of anticyclonic gyres to 0.3-0.5 g / m 3 in the Gulfs of Mexico and Guinea. Phytoplankton is represented mainly by coccolithins and peridineas, the latter can develop in coastal waters in huge quantities, causing catastrophic phenomenon"Red tide". Zooplankton of low latitudes are represented by copepods, chaetomaxillary, hyperids, hydromedusae, siphonophores and other species. There are no clearly pronounced dominant species of zooplankton at low latitudes.

Benthos is represented by large algae (macrophytes), which mostly grow on the bottom of the shelf zone, to a depth of 100 m and cover about 2% of the total area of the ocean floor. The development of phytobenthos is observed in those places where there are suitable conditions - soils suitable for anchoring to the bottom, the absence or moderate velocities of bottom currents, etc. In the high latitudes of the Atlantic Ocean, the main part of phytobenthos is made up of kelp and red algae. IN temperate zones In the northern part of the Atlantic Ocean, along the American and European coasts, there are brown algae (fucus and ascophyllum), kelp, desmarestia and red algae (furcellaria, anfeltia, etc.). Zostera is common on soft soils. The temperate and cold zones of the southern Atlantic Ocean are dominated by brown algae. In the tropical zone in the littoral zone, due to strong heating and intense insolation, vegetation on the ground is practically absent. A special place is occupied by the ecosystem of the Sargasso Sea, where floating macrophytes (mainly of three species of Sargassum algae) form clusters on the surface in the form of ribbons ranging from 100 m to several kilometers long.

Most of the biomass of nekton (actively swimming animals - fish, cephalopods and mammals) is fish. The largest number of species (75%) lives in the shelf zone, with depth and distance from the coast, the number of species decreases. The cold and temperate zones are characterized by: fish - various types of cod, haddock, pollock, herring, flounder, catfish, conger eel, etc., herring and polar sharks; among mammals - pinnipeds (harp seal, hooded seal, etc.), various species of cetaceans (whales, sperm whales, killer whales, grind, bottlenose, etc.).

There is a great deal of similarity between the faunas of the temperate and high latitudes of both hemispheres. At least 100 animal species are bipolar, that is, they are characteristic of both temperate and high belts. The tropical zone of the Atlantic Ocean is characterized by: fish - various sharks, flying fish, sailboats, various types of tuna and glowing anchovies; from animals - sea turtles, sperm whales, river dolphin inia; cephalopods are also numerous - various types of squid, octopus, etc.

The deep-sea fauna (zoobenthos) of the Atlantic Ocean is represented by sponges, corals, echinoderms, crustaceans, molluscs, and various worms.

Research history

There are three stages in the study of the Atlantic Ocean. The first is characterized by the establishment of the boundaries of the ocean and the discovery of its individual objects. In the 12-5 centuries BC, the Phoenicians, Carthaginians, Greeks and Romans left descriptions of sea voyages and the first nautical charts. Their voyages reached the Iberian Peninsula, England and the mouth of the Elbe. In the 4th century BC, Piteas (Pytheas), while sailing in the North Atlantic, determined the coordinates of a number of points and described the tidal phenomena in the Atlantic Ocean. The Canary Islands are mentioned in the 1st century AD. In the 9-10th centuries, the Normans (Eirik Raudie and his son Leif Erikson) crossed the ocean, visited Iceland, Greenland, Newfoundland and explored the shores of North America up to 40 ° north latitude. In the era of the Great geographical discoveries(mid 15th - mid 17th century) seafarers (mainly Portuguese and Spaniards) mastered the way to India and China along the coast of Africa. The most outstanding voyages during this period were made by the Portuguese B. Dias (1487), the Genoese J. Columbus (1492-1504), the Englishman J. Cabot (1497) and the Portuguese Vasco da Gama (1498), who were the first to try to measure the depths of the open parts of the ocean and speed of surface currents.

The first bathymetric map (depth map) of the Atlantic Ocean was compiled in Spain in 1529. In 1520 F. Magellan first passed from the Atlantic Ocean to the Pacific Ocean by the strait, later named after him. In the 16-17 centuries the Atlantic coast of North America was intensively explored (the British J. Davis, 1576-78, G. Hudson, 1610, W. Baffin, 1616, and other navigators whose names can be found on the map of the ocean). The Falkland Islands were discovered in 1591-92. The southern shores of the Atlantic Ocean (mainland Antarctica) were discovered and first described by the Russian Antarctic expedition of F. F. Bellingshausen and M. P. Lazarev in 1819-21. This completed the study of the boundaries of the ocean.

The second stage is characterized by the study physical properties ocean waters, temperature, salinity, currents, etc. In 1749, the Englishman G. Ellis carried out the first temperature measurements at various depths, repeated by the Englishman J. Cook (1772), the Swiss O. Saussure (1780), the Russian I.F. Kruzenshtern (1803) and others. In the 19th century, the Atlantic Ocean became a testing ground for developing new methods of exploring depths, new technology and new approaches to organizing work. For the first time, bathometers, deep-sea thermometers, thermo-depth meters, deep-water trawls and dredges are used. Among the most significant can be noted the Russian expeditions on the ships "Rurik" and "Enterprise" under the leadership of O.E. Kotzebue (1815-18 and 1823-26); English - on "Erebus" and "Terror" under the direction of J. Ross (1840-43); American - on "Seiklab" and "Arctic" under the leadership of MF Mori (1856-57). Real comprehensive oceanographic studies of the ocean began with an expedition on board the British corvette Challenger, led by C.W. Thomson (1872-76). Significant expeditions that followed her were carried out on the ships Gazelle (1874-76), Vityaz (1886-89), Valdivia (1898-1899), Gauss (1901-03). A great contribution (1885-1922) to the study of the Atlantic Ocean was made by Prince Albert I of Monaco, who organized and headed the expeditionary research on the yachts Irendel, Princess Alice, Irendel II, Princess Alice II in the northern part of the ocean. In the same years, he organized the Oceanographic Museum in Monaco. Since 1903, work began on the "standard" sections in the North Atlantic under the leadership of the International Council for the Study of the Sea (ICES) - the first international oceanographic scientific organization, which existed before the 1st World War.

The most significant expeditions in the period between the world wars were carried out on the ships "Meteor", "Discovery-II", "Atlantis". In 1931, the International Council of Scientific Unions (ICSU) was formed, which operates to the present day, organizing and coordinating ocean research.

After World War II, an echo sounder began to be widely used to study the ocean floor. This allowed us to get a real picture of the topography of the ocean floor. In the 1950s-70s, comprehensive geophysical and geological studies of the Atlantic Ocean were carried out and the features of the topography of its bottom and tectonics, the structure of the sedimentary stratum, were established. Many large forms of bottom topography (underwater ridges, mountains, trenches, fault zones, vast basins and uplifts) have been identified, and geomorphological and tectonic maps have been compiled.

The third stage of ocean research is mainly aimed at studying its role in global processes of transfer of matter and energy, and its influence on climate formation. Complexity and wide range research works demanded broad international cooperation. The Scientific Committee for Oceanographic Research (SCOR), formed in 1957, plays an important role in the coordination and organization of international research. oceanographic commission at UNESCO (IOC), operating since 1960, and other international organizations. In 1957-58, great work was carried out within the framework of the first International Geophysical Year (IGY). Subsequently, large international projects are aimed not only at studying individual parts of the Atlantic Ocean (for example, EQUALANT I-III; 1962-1964; Polygon, 1970; CICAR, 1970-75; POLYMODE, 1977; TOGA, 1985-89), but also at its study as a part of the World Ocean (GEOSECS, 1973-74; WOCE, 1990-96, and others). During the implementation of these projects, the features of the circulation of waters of various scales, the distribution and composition of suspended matter, the role of the ocean in the global carbon cycle, and many other issues were studied. In the late 1980s, the unique ecosystems of the geothermal regions of the rift zone of the ocean were investigated by Soviet deep-sea vehicles "Mir". If at the beginning of the 1980s there were about 20 international ocean research projects, then by the 21st century there were more than 100. The largest programs: International Geosphere-Biosphere Program (since 1986, 77 countries participate), it includes projects “Interaction land - ocean in coastal zone ”(LOICZ),“ Global Fluxes of Matter in the Ocean ”(JGOFS),“ Dynamics of Global Oceanic Ecosystems ”(GLOBES),“ World Climate Research Program ”(since 1980, 50 countries participate) and many others. The Global Ocean Observing System (GOOS) is being developed.

Economic use

The Atlantic Ocean occupies the most important place in the world economy among other oceans of our planet. Human use of the Atlantic Ocean, like other seas and oceans, goes in several main directions: transport and communications, fishing, production mineral resources, energy, recreation.

Transport... For 5 centuries, the Atlantic Ocean has played a leading role in maritime transport. With the opening of the Suez (1869) and Panama (1914) canals, short sea routes appeared between the Atlantic, Indian and Pacific oceans. The Atlantic Ocean accounts for about 3/5 of the world's shipping traffic; at the end of the 20th century, up to 3.5 billion tons of cargo was transported across its water area (according to IOC data). Oil, gas and oil products account for about 1/2 of the traffic volume, followed by general cargo, then iron ore, grain, coal, bauxite and alumina. The main direction of transportation is the North Atlantic, which runs between 35-40 ° north latitude and 55-60 ° north latitude. The main shipping routes connect the port cities of Europe, the USA (New York, Philadelphia) and Canada (Montreal). This direction is adjacent to the sea routes of the Norwegian, North and inland seas of Europe (Baltic, Mediterranean and Black). Mainly raw materials (coal, ores, cotton, timber, etc.) and general cargo are transported. Other important directions of transportation - South Atlantic: Europe - Central (Panama, etc.) and South America (Rio de Janeiro, Buenos Aires); East Atlantic: Europe - southern Africa (Cape Town); West Atlantic: North America, South America - southern Africa. Before the reconstruction of the Suez Canal (1981), most of the oil tankers from the Indian Basin were forced to sail around Africa.

Passenger transportation has been an important place in the Atlantic Ocean since the 19th century, when mass emigration from the Old World to America began. The first steam-sailing vessel "Savannah" crossed the Atlantic Ocean in 28 days in 1818. At the beginning of the 19th century, the Blue Ribbon Prize was established for passenger ships that would cross the ocean faster. This prize was awarded, for example, to such famous liners as "Lusitania" (4 days and 11 hours), "Normandy" (4 days and 3 hours), "Queen Mary" (4 days without 3 minutes). Last time The Blue Ribbon was awarded to the American liner United States in 1952 (3 days and 10 hours). At the beginning of the 21st century, the duration of a passenger liner flight between London and New York was 5-6 days. The maximum passenger traffic across the Atlantic Ocean occurred in 1956-57, when more than 1 million people were transported a year, in 1958 the volume of passenger traffic by air was equal to sea transport, and then more and more passengers prefer air transport (the record flight time of a supersonic liner "Concorde" on the route New York - London - 2 hours 54 minutes). The first non-stop flight across the Atlantic Ocean was made on 14-15 June 1919 by the English pilots J. Alcock and A. W. Brown (Newfoundland Island - the island of Ireland), the first non-stop flight across the Atlantic Ocean alone (from continent to continent) 20-21 May 1927 - American pilot C. Lindbergh (New York - Paris). At the beginning of the 21st century, almost all the flow of passengers across the Atlantic Ocean is served by aviation.

Connection... In 1858, when there was no radio communication between the continents, the first telegraph cable was laid across the Atlantic Ocean. By the end of the 19th century, 14 telegraph cables connected Europe with America and 1 with Cuba. In 1956, the first telephone cable was laid between the continents; by the mid-1990s, over 10 telephone lines were operating on the ocean floor. In 1988, the first transatlantic fiber-optic communication line was laid; in 2001, 8 lines were in operation.

Fishing... The Atlantic Ocean is considered the most productive ocean and its biological resources are most intensively exploited by humans. In the Atlantic Ocean, fishing and seafood production account for 40-45% of the total world catch (an area of about 25% of the World Ocean). Most of the catch (up to 70%) is made up of herring fish (herring, sardines, etc.), cod fish (cod, haddock, hake, whiting, pollock, navaga, etc.), flounder, halibut, sea bass. The catch of molluscs (oysters, mussels, squid, etc.) and crustaceans (lobsters, crabs) is about 8%. According to FAO estimates, the annual catch of fish products in the Atlantic Ocean is 85-90 million tons, but for most of the fishing areas of the Atlantic, fish catch reached its maximum in the mid-1990s and its increase is undesirable. The traditional and most productive fishing area is the northeastern part of the Atlantic Ocean, including the North and Baltic Seas (mainly herring, cod, flounder, sprats, mackerel). In the northwestern region of the ocean, on the Newfoundland banks, cod, herring, flounder, squid, etc. have been caught for many centuries. In the central part of the Atlantic Ocean, there is a catch of sardine, horse mackerel, mackerel, tuna, etc. -Falkland Shelf, fishing both warm-water species (tuna, marlins, swordfish, sardines, etc.) and cold-water species (blue whiting, hake, notothenia, toothfish, etc.). Sardines, anchovy and hake are caught off the coast of western and southwestern Africa. In the Antarctic region of the ocean, planktonic crustaceans (krill), marine mammals, from fish - notothenia, toothfish, silverfish, etc. are of commercial importance. Until the middle of the 20th century, active fishing was carried out in the high-latitude northern and southern regions of the ocean different types pinnipeds and cetaceans, but in recent decades it has sharply decreased due to the depletion of biological resources and thanks to environmental protection measures, including intergovernmental agreements on limiting their production.

Mineral resources... The mineral wealth of the ocean floor is being exploited more and more actively. Oil and combustible gas deposits have been studied more fully, the first mention of their exploitation in the Atlantic Ocean basin dates back to 1917, when oil production began on an industrial scale in the eastern part of the Maracaibo lagoon (Venezuela). Largest centers offshore mining: Gulf of Venezuela, Maracaibo lagoon (Maracaibo oil and gas basin), Gulf of Mexico (Gulf of Mexico oil and gas basin), Gulf of Paria (Orinoco oil and gas basin), Brazilian shelf (Sergipe-Alagoas oil and gas basin), Gulf of Guinea (Sea of Guinea basin) oil and gas basin (Oil and gas bearing region of the North Sea), etc. Placer deposits of heavy minerals are widespread along many coasts. The largest development of placer deposits of ilmenite, monocyte, zircon, rutile is carried out off the coast of Florida. Such deposits are located in the Gulf of Mexico, off the east coast of the United States, as well as in Brazil, Uruguay, Argentina and the Falkland Islands. On the shelf of southwest Africa, offshore diamond deposits are being developed. Gold-bearing placers were found off the coast of Nova Scotia at depths of 25-45 m. One of the world's largest iron ore deposits, Wabana (in Conception Bay off the coast of Newfoundland), has been explored in the Atlantic Ocean; iron ore is also mined off the coast of Finland, Norway and France. In the coastal waters of Great Britain and Canada, coal deposits are being developed, it is mined in mines located on land, the horizontal workings of which go under the seabed. Large sulfur deposits are being developed on the shelf of the Gulf of Mexico. In the coastal zone of the ocean, sand is mined for construction and the production of glass, gravel. Phosphorite-bearing sediments have been explored on the shelf of the east coast of the United States and the west coast of Africa, but their development is not yet profitable. The total mass of phosphorites on the continental shelf is estimated at 300 billion tons. At the bottom of the North American Basin and on the Blake Plate, large fields of ferromanganese nodules have been found, their total reserves in the Atlantic Ocean are estimated at 45 billion tons.

Recreational resources... From the 2nd half of the 20th century great importance for the economies of coastal countries has the use recreational resources ocean. Old resorts are developing and new ones are being built. Since the 1970s, ocean liners designed only for cruises have been laid, they are distinguished by their large size (displacement of 70 thousand tons or more), an increased level of comfort and relative slowness. The main routes of the Atlantic Ocean cruise ships are the Mediterranean and the Caribbean and the Gulf of Mexico. From the late 20th - early 21st centuries, scientific tourism and extreme cruise routes have been developing, mainly in the high latitudes of the Northern and Southern Hemispheres. In addition to the Mediterranean and Black Sea basins, the main resort centers are located in the Canary Islands, Azores, Bermuda, the Caribbean Sea and the Gulf of Mexico.

Energy... The energy of the tides of the Atlantic Ocean is estimated at about 250 million kWh. In the Middle Ages, tidal wave mills and sawmills were built in England and France. A tidal power plant operates at the mouth of the Rance River (France). The use of hydrothermal energy of the ocean (the difference in temperature in surface and deep waters) is also considered promising; a hydrothermal station operates on the coast of Cote d'Ivoire.

Port cities... Most of the world's major ports are located on the shores of the Atlantic Ocean: in Western Europe - Rotterdam, Marseille, Antwerp, London, Liverpool, Genoa, Le Havre, Hamburg, Augusta, Southampton, Wilhelmshaven, Trieste, Dunkirk, Bremen, Venice, Gothenburg, Amsterdam, Naples, Nantes Saint Nazaire, Copenhagen; in North America - New York, Houston, Philadelphia, Baltimore, Norfolk-Newport, Montreal, Boston, New Orleans; in South America - Maracaibo, Rio de Janeiro, Santos, Buenos Aires; in Africa - Dakar, Abi-jan, Cape Town. Russian port cities do not have direct output to the Atlantic Ocean and are located on the shores of the inland seas belonging to its basin: St. Petersburg, Kaliningrad, Baltiysk (Baltic Sea), Novorossiysk, Tuapse (Black Sea).

Lit .: Atlantic Ocean. M., 1977; Safyanov G. A. Coastal zone of the ocean in the XX century. M., 1978; Terms. Concepts, reference tables / Edited by S.G. Gorshkov. M., 1980; Atlantic Ocean. L., 1984; Biological Resources of the Atlantic Ocean / Otv. editor D. E. Gershanovich. M., 1986; Broeker W. S. The great ocean conveyor // Oceanograpy. 1991. Vol. 4. No. 2; Pushcharovsky Yu. M. Atlantic tectonics with elements of nonlinear geodynamics. M., 1994; World ocean atlas 2001: In 6 vol. Silver Spring, 2002.

P. N. Makkaveev; AF Limonov (geological structure).

The Atlantic Ocean is second only to the Pacific Ocean in size, its area is approximately 91.56 million km². It is distinguished from other oceans by a strong indented coastline, which forms numerous seas and bays, especially in the northern part. In addition, the total area of river basins flowing into this ocean or its marginal seas is much larger than that of rivers flowing into any other ocean. Another distinctive feature of the Atlantic Ocean is the relatively small number of islands and the complex topography of the seabed, which, thanks to underwater ridges and uplifts, forms many separate basins.

North Atlantic Ocean

Borders and coastline. The Atlantic Ocean is divided into northern and southern parts, the border between which is conventionally drawn along the equator. From an oceanographic point of view, however, the equatorial countercurrent located at 5-8 ° N should be attributed to the southern part of the ocean. The northern border is usually drawn along the Arctic Circle. In places, this border is marked by underwater ridges.

In the Northern Hemisphere, the Atlantic Ocean has a highly indented coastline... Its relatively narrow northern part is connected to the Arctic Ocean by three narrow straits. In the northeast, the Davis Strait, 360 km wide (at the latitude of the Arctic Circle), connects it with the Baffin Sea, which belongs to the Arctic Ocean. In the central part, between Greenland and Iceland, there is the Danish Strait, which is only 287 km wide at its narrowest point. Finally, in the northeast, between Iceland and Norway, lies the Norwegian Sea, approx. 1220 km. To the east of the Atlantic Ocean, two water areas deeply protruding into the land are cut off. The northernmost of them begins with the North Sea, which, to the east, passes into the Baltic Sea with the Gulf of Bothnia and the Gulf of Finland. To the south, there is a system of inland seas - the Mediterranean and the Black - with a total length of approx. 4000 km In the Strait of Gibraltar, which connects the ocean with the Mediterranean Sea, there are one under the other two oppositely directed currents. A lower position is occupied by the current heading from the Mediterranean Sea to the Atlantic Ocean, since Mediterranean waters, due to more intense evaporation from the surface, are characterized by higher salinity and, therefore, higher density.

In the tropical zone in the southwest of the North Atlantic are the Caribbean Sea and the Gulf of Mexico, connected to the ocean by the Florida Strait. The coast of North America is indented by small bays (Pamlico, Barnegat, Chesapeake, Delaware and Long Island Sound); in the northwest are the Bays of Fundy and St. Lawrence, Bell Isle, Hudson Strait and Hudson Bay.

The largest islands are concentrated in the northern part of the ocean; these are the British Isles, Iceland, Newfoundland, Cuba, Haiti (Hispaniola) and Puerto Rico. On the eastern edge of the Atlantic Ocean there are several groups of small islands - the Azores, Canary Islands, Cape Verde. There are similar groups in the western part of the ocean. Examples include the Bahamas, Florida Keys and Lesser Antilles. The archipelagos of the Greater and Lesser Antilles form an island arc surrounding eastern part The Caribbean. In the Pacific Ocean, such island arcs are characteristic of deformation regions crust... Deep-sea trenches are located along the convex side of the arc.

The bottom of the North Atlantic Ocean has a complex rugged relief formed by a combination of underwater ridges, hills, hollows and gorges. Most of the ocean floor, from a depth of about 60 m and up to several kilometers, is covered with thin silty deposits of dark blue or bluish green color. A relatively small area is occupied by rocky outcrops and areas of gravel-pebble and sandy deposits, as well as deep-water red clays.

Telephone and telegraph cables have been laid on the shelf in the North Atlantic Ocean to connect North America with North-West Europe. Here, to the region of the North Atlantic shelf are confined to the areas of industrial fishing, which are among the most productive in the world.

In the central part of the Atlantic Ocean passes, almost repeating the outlines of the coastlines, a huge underwater mountain range approx. 16 thousand km, known as the Mid-Atlantic Ridge. This ridge divides the ocean into two approximately equal parts. Most of the peaks of this underwater ridge do not reach the ocean surface and are at a depth of at least 1.5 km. Some of the highest peaks rise above sea level and form the islands - the Azores in the North Atlantic and Tristan da Cunha - in the South. In the south, the ridge skirts the coast of Africa and continues further north into the Indian Ocean. A rift zone extends along the axis of the Mid-Atlantic Ridge.

Surface currents in the North Atlantic Ocean move clockwise. The main elements of this large system are the north-facing warm current Gulf Stream, as well as the North Atlantic, Canary and North Passat (Equatorial) currents. The Gulf Stream follows from the Florida Strait and Cuba Island in a northerly direction along the coast of the United States and at about 40 ° N. NS. deviates to the northeast, changing its name to the North Atlantic Current. This current splits into two branches, one of which follows to the northeast along the coast of Norway and further into the Arctic Ocean. It is thanks to her that the climate of Norway and all of northwestern Europe is significantly warmer than one would expect at latitudes corresponding to the region stretching from Nova Scotia to southern Greenland. The second branch turns south and further south-west along the coast of Africa, forming the cold Canary Current. This current moves to the southwest and connects with the North Passat Current, which heads west towards the West Indies, where it merges with the Gulf Stream. To the north of the North Tradewind Current lies an area of stagnant waters teeming with algae known as the Sargasso Sea. The cold Labrador Current runs along the North Atlantic coast of North America from north to south, flowing from Baffin Bay and the Labrador Sea and cooling the shores of New England.

South Atlantic Ocean

Some experts attribute to the Atlantic Ocean in the south the entire body of water up to the Antarctic ice sheet; others take for the southern boundary of the Atlantic an imaginary line connecting Cape Horn in South America to the Cape Good Hope in Africa. The coastline in the southern part of the Atlantic Ocean is much less indented than in the northern one; there are also no inland seas along which the influence of the ocean could penetrate deep into the continents of Africa and South America. The only major bay on the African coast is the Guinean bay. There are also few large bays on the coast of South America. The southernmost tip of this continent, Tierra del Fuego, has a rugged coastline bordered by numerous small islands.

There are no large islands in the South Atlantic Ocean, but there are isolated isolated islands, such as Fernando de Noronha, Ascension, Sao Paulo, St. Helena, the Tristan da Cunha archipelago, and in the extreme south - Bouvet, South Georgia , South Sandwich, South Orkney, Falkland Islands.

In addition to the Mid-Atlantic Ridge, there are two main submarine mountain ranges in the South Atlantic. The whale ridge stretches from the southwestern tip of Angola to about. Tristan da Cunha, where it joins the Mid-Atlantic. The Rio de Janeiro ridge stretches from the islands of Tristan da Cunha to the city of Rio de Janeiro and is a group of separate seamounts.

The main systems of currents in the South Atlantic Ocean move counterclockwise. The South Tradewind Current is directed to the west. At the bulge of the eastern coast of Brazil, it splits into two branches: the northern one carries waters along the northern coast of South America to the Caribbean, and the southern, warm Brazilian Current, moves south along the coast of Brazil and joins the West Winds, or Antarctic Current, which heads east and then northeast. Part of this cold current separates and carries its waters northward along the African coast, forming the cold Benguela Current; the latter eventually joins the South Tradewind Current. The warm Guinean Current moves south along the shores of Northwest Africa into the Gulf of Guinea.

ATLANTIC OCEAN, part of the World Ocean, bounded by Europe and Africa from the east and North and South America from the west. Its name supposedly comes from the Atlas Mountains in northern Africa or from the mythical lost continent of Atlantis.
The Atlantic Ocean is second only to the Pacific Ocean in size; its area is approximately 91.56 million km2. It is distinguished from other oceans by a strong indented coastline, which forms numerous seas and bays, especially in the northern part. In addition, the total area of river basins flowing into this ocean or its marginal seas is much larger than that of rivers flowing into any other ocean. Another distinctive feature of the Atlantic Ocean is the relatively small number of islands and a complex bottom topography, which, thanks to underwater ridges and uplifts, forms many separate basins.

NORTHERN ATLANTIC OCEAN

Borders and coastline.

The Atlantic Ocean is divided into northern and southern parts, the border between which is conventionally drawn along the equator. From an oceanographic point of view, however, the equatorial countercurrent located at 5-8 ° N should be attributed to the southern part of the ocean. The northern border is usually drawn along the Arctic Circle. In places, this border is marked by underwater ridges.

In the Northern Hemisphere, the Atlantic Ocean has a heavily indented coastline. Its relatively narrow northern part is connected to the Arctic Ocean by three narrow straits. In the northeast, the Davis Strait, 360 km wide (at the latitude of the Arctic Circle), connects it with the Baffin Sea, which belongs to the Arctic Ocean. In the central part, between Greenland and Iceland, there is the Danish Strait, which is only 287 km wide at its narrowest point. Finally, in the northeast, between Iceland and Norway, lies the Norwegian Sea, approx. 1220 km. To the east of the Atlantic Ocean, two water areas deeply protruding into the land are cut off. The northernmost of them begins with the North Sea, which, to the east, passes into the Baltic Sea with the Gulf of Bothnia and the Gulf of Finland. To the south, there is a system of inland seas - the Mediterranean and the Black - with a total length of approx. 4000 km In the Strait of Gibraltar, which connects the ocean with the Mediterranean Sea, there are one under the other two oppositely directed currents. A lower position is occupied by the current heading from the Mediterranean Sea to the Atlantic Ocean, since the Mediterranean waters, due to more intense evaporation from the surface, are characterized by higher salinity and, therefore, higher density.

Islands.

The largest islands are concentrated in the northern part of the ocean; these are the British Isles, Iceland, Newfoundland, Cuba, Haiti (Hispaniola) and Puerto Rico. On the eastern edge of the Atlantic Ocean there are several groups of small islands - the Azores, Canary Islands, Cape Verde. There are similar groups in the western part of the ocean. Examples include the Bahamas, Florida Keys and Lesser Antilles. The archipelagos of the Greater and Lesser Antilles form an island arc surrounding the eastern Caribbean. In the Pacific Ocean, such island arcs are characteristic of deformation regions of the earth's crust. Deep-sea trenches are located along the convex side of the arc.

Bottom relief.

The Atlantic Ocean Basin is bordered by a shelf, the width of which varies. The shelf is cut by deep gorges - the so-called. underwater canyons. Their origin is still controversial. According to one theory, the canyons were carved by rivers when the sea level was below modern. Another theory associates their formation with the activity of turbidity currents. It has been suggested that turbidity currents are the main agent for sedimentation on the ocean floor and that it is they that cut through the underwater canyons.
The bottom of the North Atlantic Ocean has a complex rugged relief formed by a combination of underwater ridges, hills, hollows and gorges. Most of the ocean floor, from a depth of about 60 m and up to several kilometers, is covered with thin, dark blue or bluish green silty deposits. A relatively small area is occupied by rocky outcrops and areas of gravel-pebble and sandy deposits, as well as deep-water red clays.

A rift zone extends along the axis of the Mid-Atlantic Ridge.

Currents.

Surface currents in the North Atlantic Ocean move clockwise. The main elements of this large system are the north-facing warm Gulf Stream, as well as the North Atlantic, Canary and North Passat (Equatorial) currents. The Gulf Stream follows from the Florida Strait and Cuba Island in a northerly direction along the coast of the United States and at about 40 ° N. deviates to the northeast, changing its name to the North Atlantic Current. This current splits into two branches, one of which follows to the northeast along the coast of Norway and further into the Arctic Ocean. It is thanks to her that the climate of Norway and all of northwestern Europe is significantly warmer than one would expect at latitudes corresponding to the region stretching from Nova Scotia to southern Greenland. The second branch turns south and further south-west along the coast of Africa, forming the cold Canary Current. This current moves to the southwest and connects with the North Passat Current, which heads west towards the West Indies, where it merges with the Gulf Stream. To the north of the North Tradewind Current lies an area of stagnant waters teeming with algae known as the Sargasso Sea. The cold Labrador Current runs along the North Atlantic coast of North America from north to south, flowing from Baffin Bay and the Labrador Sea and cooling the shores of New England.

SOUTH ATLANTIC OCEAN

Borders and coastline.

Some experts attribute to the Atlantic Ocean in the south the entire body of water up to the Antarctic ice sheet; others mistake the imaginary line connecting Cape Horn in South America with the Cape of Good Hope in Africa for the southern boundary of the Atlantic. The coastline in the southern part of the Atlantic Ocean is much less indented than in the northern one; there are also no inland seas along which the influence of the ocean could penetrate deep into the continents of Africa and South America. The only major bay on the African coast is the Guinean bay. There are also few large bays on the coast of South America. The southernmost tip of this continent, Tierra del Fuego, has a rugged coastline bordered by numerous small islands.

Islands.

There are no large islands in the South Atlantic Ocean, but there are isolated isolated islands, such as Fernando de Noronha, Ascension, Sao Paulo, St. Helena, the Tristan da Cunha archipelago, and in the extreme south - Bouvet, South Georgia , South Sandwich, South Orkney, Falkland Islands.

Bottom relief.

Currents.

The Atlantic Ocean is considered one of the largest and most voluminous in size, namely the second largest after the Pacific Ocean. This ocean is the most studied and developed when compared with other water areas. Its location is as follows: from the east it is framed by the shores of North and South America, and in the west its borders end in Europe and Africa. In the South, it passes into the Southern Ocean. And on the north side it borders on Greenland. The ocean is distinguished by the fact that there are very few islands in it, and the relief of its bottom is all speckled and has a complex structure. The coastline is broken.

Characteristics of the Atlantic Ocean

If we talk about the area of the ocean, then it occupies 91.66 million square meters. km. We can say that part of its territory is not the ocean itself, but the existing seas and bays. The volume of the ocean is 329.66 million square meters. km, and its average depth is 3736 m. Where the Puerto Rico trench is located, it is considered the deepest ocean depth, which is 8742 m. There are two currents - North and South.

Atlantic Ocean from the north side

The ocean border from the north is marked in some places by ridges located under water. In this hemisphere, the Atlantic is framed by a jagged coastline. A small northern part of it is connected to the Arctic Ocean by several narrow straits. Davis Strait is located in the northeast and connects the ocean with the Baffin Sea, which is also considered to be part of the Arctic Ocean. Closer to the center, the Danish Strait is less wide than the Davis. Between Norway and Iceland, closer to the northeast is the Norwegian Sea.

In the southwest of the North Current is the Gulf of Mexico, which is connected by the Florida Strait. And also the Caribbean Sea. Many bays can be noted here, such as Barnegat, Delaware, Hudson Bay and others. It is in the north side of the ocean that you can see the largest and largest islands, which are famous for their fame. These are Puerto Rico, the world famous Cuba and Haiti, as well as the British Isles and Newfoundland. Closer to the east, small clusters of islands can be found. These are the Canary Islands, Azores and Cape Verde. Closer to the west - the Bahamas, Lesser Antilles.

South Atlantic Ocean

Some geographers believe that the southern part is the entire space up to Antarctica. Someone defines the border at Cape Horn and the Cape of Good Hope of two continents. The coast in the south of the Atlantic Ocean is not as indented as in the north, and there are no seas. There is one large bay near Africa - the Guinean bay. The farthest point in the south is Tierra del Fuego, which is framed by small islands in a large number... Also, you cannot find large islands here, but there are separate islands, like about. Ascension, St. Helena, Tristan ─ da Cunha. In the extreme south, you can find the South Islands, Bouvet, Falkland Islands and others.

As for the current in the south of the ocean, here all systems flow counterclockwise. Near the east of Brazil, the South Trade Wind forks. One branch goes north, flows near the northern coast of South America, filling the Caribbean. And the second is considered southern, very warm, moves near Brazil and soon connects with the Antarctic Current, then goes to the east. Partially separates and turns into the Benguela Current, which is distinguished by its cold waters.

Atlantic Ocean attractions

The Belize Barrier Reef has a very special underwater cave. They called it the Blue Hole. It is very deep, and inside it there is a whole series of caves, which are connected with each other by tunnels. The cave reaches 120 m deep and is considered unique in its kind.

There is no person who does not know about Bermuda Triangle... But it is located in the Atlantic Ocean and excites the imagination of many superstitious travelers. Bermuda shorts beckon with their mystery, but at the same time they frighten with the unknown.

It is in the Atlantic that you can see an unusual sea that has no shores. And all because it is located in the middle of a body of water, and its boundaries cannot be framed by land, only currents show the boundaries of this sea. This is the only sea in the world that has such unique data and is called the Sargasso Sea.

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, Black, Caribbean) and the Gulf (Biscay, Guinean, Mexican). In the southern hemisphere, the shores are little indented (there is only one open sea, Vedella). Inland and marginal seas occupy about 16% of the area.

1. General characteristics

1.1. Conditional boundaries

between the coast of Canada and the southern tip of Greenland, the Atlantic Sea of Labrador borders the Davis Strait (the dividing line between the Labrador Sea and the Davis Strait runs from the intersection of the 60th parallel with the coast of the Labrador Peninsula)
from Cape Wedel on the east coast of Greenland (extreme northern point 68 37 "24.9" N) a straight line to Cape Streymnes in northwest Iceland delimits the Atlantic Ocean and the Greenland Sea of the Arctic Ocean;
from Cape Bardneshodn in the east of Iceland there is a broken line of the border between the Atlantic Ocean and the Norwegian Sea - through the northern edge of Viyoi Island (far north of the Faroe Islands) and a point on the 61st parallel north of Anst Island (Shetland Islands). Further along the 61st parallel to the coast of Norway, the border continues between the Norwegian Sea of the Arctic Ocean and the Atlantic North Sea (in the area of the Sognesean channel at the southern entrance to the Sognefjord).

In the South-West The Pacific Ocean, which includes the Strait of Magellan

In the southeast off the coast of Africa, the Atlantic Ocean borders the Indian Ocean

To the south a special Southern Ocean surrounding Antarctica is allocated from the Atlantic

1.2. Width

Maximum width

Minimum width

2. Bottom relief

4. Hydrological regime

Physical map of the Atlantic Ocean

The hydrological regime is mainly determined by the climate. Currents caused by atmospheric circulation form a complex system of movement of the surface layer of the Atlantic Ocean. Thanks to the trade winds, the North and South Equatorial currents arise, which have a westerly direction. Further, in the tropics and temperate latitudes, they form anticyclonic circulation rings. An integral part rings in the Northern Hemisphere have warm currents of the Antilles and the Gulf Stream. An offshoot of the Gulf Stream forms the Canary Cold Current. In the northwest, the cold currents of East Greenland and Labrador flow into the Atlantic Ocean. The coast of Brazil is washed by the warm current of the same name. Sloping eastward, it merges into the drifting current of the West Winds. At the southwestern coast of Africa, its northern branch forms a cold Bengel current. The distribution of water temperatures is associated with the currents. In the Northern Hemisphere, thanks to the Gulf Stream, water temperatures are significantly higher than in the Southern, where the cooling effect of Antarctica affects. The distribution of water temperatures is generally similar to the distribution of air temperatures. The typical salinity of the Atlantic Ocean is 35.4%. The highest salinity is observed in tropical and subtropical latitudes of both hemispheres, where there is little rainfall and high evaporation. With depth, the water temperature decreases, the salinity of the water decreases. In the bottom layer, the water temperature is from 0 to +2, salinity is 34.6 - 34.9%. The amplitude of the tides in the Atlantic Ocean varies widely. In the open ocean, it does not exceed 1 m. In the Bay of Fundy, the known tides are up to 18 m, which are the maximum for the world's oceans. Ice in the form of coastal fast ice is known only in Antarctica. More common is floating ice of marine and continental origin, which can float into mid-latitudes.

To the Atlantic Ocean flow: Amazon, Dnieper, Don, Danube, Congo, St. Lawrence River, Mackenzie, Mississippi, Niger, Nile, Orinoco, Parana, Rhine and others, giving together about 60% of the mass of continental waters flowing to the oceans.

5. Plant and animal world

Vegetable and animal world in the tropical zone it is distinguished by a variety of species, but a limited number of individuals; in the temperate and cold zones, on the contrary. The bottom vegetation is represented by various algae, which are widespread in the coastal zone to a depth of 100 m.Phytoplankton in temperate and cold latitudes extends to a depth of 50 m, in the tropics - up to 50-80 m.In the water column, phytoplankton dominates, consisting of dinoflagellates and diatoms algae. In the midst of their seasonal bloom, the sea off the coast of Florida turns bright red, and a liter of seawater contains tens of millions of unicellular plants. Donna flora is represented by brown (fucus, kelp), green, red algae and some vascular plants. At the mouths of the rivers, Zostera seaweed grows, and in the tropics, green (Caulerps, Wallonia) and storms (Sargasum) algae prevail. The southern part of the ocean is characterized by brown algae (fucus, lesonia, elektus).

The most development of life is marked by the stripes at the junction of the cold and temperate zones. They are the main fishing areas: the Bank of Newfoundland, Icelandic waters, the North Sea and the whaling areas of the Southern Hemisphere.

Herring, cod, and salmon fish are of the greatest industrial importance. More than half of the world's catch of cod, herring, mackerel, tuna and sardines comes from the North Atlantic Ocean. In the 1970s, as a result of overfishing of some fish species, the volume of fishery decreased sharply, but after the introduction of strict limits, fish stocks are gradually recovering.

6. Economic and political significance

Economically and politically, the Atlantic Ocean is of great international importance. It is a junction of important economic and strategic sea routes. The most important are the lines: North Atlantic (between Europe, USA and Canada), Far Eastern (between Europe and Asia and Australia, through Suez), Mid-Atlantic (between Europe, West Indies and South America). Natural resources The overwhelming majority of countries in the world enjoy the Atlantic Ocean. The main ports of the Atlantic Ocean and the seas of its basin: Odessa (Ukraine), Amsterdam, Rotterdam (Netherlands), London, Liverpool (Great Britain), Hamburg (Germany), Marseille (France), Cape Town (South Africa), Lagos (Nigeria), Buenos- Aires (Argentina), Rio de Janeiro (Brazil), Halifax (Canada), Boston, New Orleans, New York, Houston (USA), Genoa (Italy), St. Petersburg (Russia).

7. Research

The first philosopher of antiquity to use the word "Atlantic" in his works was the Greek historian Herodotus, who wrote that "the sea on which the Hellenes swim, and that beyond the Pillars of Hercules, is called the Atlantic". The term "Atlantic Ocean" is established in the ancestors of Yeratosthenes of Kirensky (III century BC) and Plinia the Elder (I century BC), albeit in that, since the water itself was known in ancient times, in the past it was not remembered. You can, so they called the aquatorium between the Gibraltarskoy channel and the Canary Islands.

Back to the era of great geographic views, the vastness of the Atlantic was plagued by the number of ships of the Vikings, Carthaginians, Finnish, Normans and Basques. For example, the tribes "I Basque settled on the Pireneyskiy pіostrovі before the emergence on the continents of the Indo-European peoples. Being in the Ribal prominence, but I don’t have access to the quiet bays of the Middle-Earth Sea, the Basques have completely buried the capital. reached the "Earth in" Yalenoi Ribi "(Newfoundland Island) along that side of the Atlantic: there are waters and donines famous for rich ribbons. X-XI Art. Normans added a new side to the pivnichnaya part of the Atlantic Ocean. On the thought of a large number of pre-Columbian views, the Scandinavian Vikings first and more than once overflowed the ocean, reaching the shores of the American continent (the stench called it Winland) and brought up Greenland and Labrador.

Through the capital of the expedition of Christopher Columbus, they mapped the islands of the Caribbean Basin and the majestic continent, from the name of America, to the map. The English did not bother to order to the winter-skid shores of the New Svitu decilka of the pre-daily expeditions, as they chose even more prices, and in 1529 p. Spanish cartographers have laid down a map of the private part of the Atlantic, which is located on the western shores of Europe and Africa, and marked on some of the most important miles of the reef.

In the end of the 15th century, there is a supernatural culture between Spain and Portugal for panuvannya in the Atlantics, the walls have become stark, and the Vatican has gotten involved in the confrontation. In 1494, there were signed contracts, yakim vdovzh 48-49 of the old dovgoti stood in the so-called. "Papa Meridian". All lands at the end of the New Boule were from Spain, and at the last - from Portugal. In the 16th century, in the world of colonial wealth development, the Atlantic began to sail regularly, and gold, silver, expensive stones, pepper, cocoa and tsukor were transported to Europe. In the same way, they were delivered to America with wild animals, textiles, alcohol, products and slaves for plantations of bavaria and candied reeds. Vidtak, in the XVI-XVII centuries. In these regions, there was a priestly business and privateering, and many famous pirates, such as John Hawkins, Francis Drake and Henry Morgan, wrote their names in history.