ATLANTIC OCEAN(Latin name Mare Atlanticum, Greek 'Ατλαντίς - denoted the space between the Strait of Gibraltar and the Canary Islands, the entire ocean was called Oceanus Occidentalis - Western ca.), the second largest ocean on Earth (after the Pacific ca.), part Worldwide approx. Modern name first appeared in 1507 on the map of the Lorraine cartographer M. Waldseemüller.
Physiographical sketch
General information
In the north, the border of A. o. with the Arctic basin approx. passes along the east. entrance to Hudson Strait, then through Davis Strait. and along the coast of Greenland to Cape Brewster, through the Danish Strait. to Cape Røydinupyur on the island. Iceland, along its coast to Cape Gerpir (Terpir), then to the Faroe Islands, then to the Shetland Islands and along 61° N. w. to the coast of the Scandinavian Peninsula. In the east of A. o. limited by the shores of Europe and Africa, in the west by the shores of the North. America and South America. Border of A. o. with Indian approx. draw along a line running from Cape Agulhas along the meridian 20° east. to the coast of Antarctica. Border with the Pacific approx. carried out from Cape Horn along the meridian 68°04′ W. or at the shortest distance from South. America to the Antarctic Peninsula through the Strait. Drake, from Fr. Oste to Cape Sternek. South part of A. o. sometimes called the Atlantic sector of the South Caucasus, drawing the border along the subantarctic zone. convergence (approximately 40° S). Some works propose the division of A. o. to the North and Yuzh. The Atlantic Oceans, but it is more common to view it as a single ocean. A. o. – the most biologically productive of the oceans. It contains the longest underwater ocean. ridge – Mid-Atlantic Ridge; the only sea that does not have solid shores, limited by currents, is Sargasso Sea; hall. Fundy with the highest tidal wave; to the A. o. pool applies Black Sea with a unique hydrogen sulfide layer.
A. o. stretches from north to south for almost 15 thousand km, its smallest width is approx. 2830 km in the equatorial part, the largest – 6700 km (along the parallel of 30° N). Area of A. o. with seas, bays and straits 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. Wed. depth 3597 m, greatest – 8742 m (trench Puerto Rico). The most easily accessible shelf zone of the ocean (with depths up to 200 m) occupies approx. At 5% of its area (or 8.6% if seas, bays and straits are taken into account), its area is larger than that of the Indian and Pacific Oceans, and significantly smaller than that of 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 seas and bays, more than 70% is the ocean bed (abyssal zone). See map.
Seas
In the basin of A. o. - numerous seas, which are divided into: internal - Baltic, Azov, Black, Marmara and Mediterranean (the latter, in turn, includes the following seas: Adriatic, Alboran, Balearic, Ionian, Cyprus, Ligurian, Tyrrhenian, Aegean); interisland – Irish and int. western seas coast of Scotland; marginal - Labrador, Northern, Sargasso, Caribbean, Scotia (Scotia), Weddell, Lazareva, west. part of the Riiser-Larsen (see separate article on the seas). The largest bays of the ocean: Biscay, Bristol, Guinea, Mexico, Maine, St. Lawrence. The most important straits of the ocean: Great Belt, Bosphorus, Gibraltar, Dardanelles, Danish, Davis, Drake, Oresund (Sund), Cabot, Kattegat, Kerch, English Channel (including Pas de Calais), Little Belt, Messina, Skagerrak , Florida, Yucatan.
Islands
Unlike other oceans, in A. o. there are few seamounts, guyots and coral reefs, and there are no coastal reefs. The total area of the islands of A. o. OK. 1070 thousand km 2. Basic 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, Tierra del Fuego archipelago (Terra del Fuego, Oste, Navarino) , Marajo, Sicily, Sardinia, Lesser Antilles, Falklands (Malvinas), Bahamas, etc. open ocean there are small islands: the Azores, Sao Paulo, Ascension, Tristan da Cunha, Bouvet (on the Mid-Atlantic Ridge), etc.
Shores
Coastline in the north. parts of A. o. heavily indented (see also Shore), almost all large inland seas and bays are located here, in the south. parts of A. o. The banks are slightly indented. The coasts of Greenland, Iceland and the coast of Norway are predominant. tectonic-glacial dissection of fjord and fiard types. Further south, in Belgium, they give way to sandy, shallow shores. Coast of Flanders ch. arr. arts origin (coastal dams, polders, canals, etc.). Shores of the island Great Britain and about. Ireland has abrasion bays, high limestone cliffs alternating with sandy beaches and muddy drainage areas. The Cotentin Peninsula has rocky shores, sandy and gravel beaches. North The coast of the Iberian Peninsula is composed of rocks; to the south, off the coast of Portugal, sandy beaches predominate, often enclosing lagoons. Sandy beaches also border the shores of the West. Sahara and Mauritania. To the south of Cape Zeleny there are leveled abrasion-bay shores with mangroves. Zap. The Ivory Coast site has an accumulative coastline with rocky headlands. To the southeast, to the vast river delta. Niger is an accumulative coast, which means. number of spits, lagoons. In the southwest Africa - accumulative, less often abrasion-bay shores with extensive sandy beaches. The coast of southern Africa is of abrasion-bay type and is composed of solid crystalline rocks. breeds Arctic shores Canada abrasive, with high cliffs, glacial deposits and limestones. To the east Canada and northern parts of the hall St. Lawrence contains intensively eroded cliffs of limestone and sandstone. In the west and south there is a hall. St. Lawrence – wide beaches. On the shores of the Canadian provinces of Nova Scotia, Quebec, and Newfoundland there are outcrops of solid crystalline particles. breeds From approximately 40° N. w. to Cape Canaveral in the USA (Florida) - alternation of leveled accumulative and abrasive types of shores composed of loose rocks. Coast of the Gulf of Mexico. low-lying, bordered by mangroves in Florida, sand barriers in Texas and deltaic shores in Louisiana. On the Yucatan Peninsula there are cemented beach sediments, to the west of the peninsula there is an alluvial-marine plain with coastal levees. On the coast of the Caribbean Sea, abrasion and accumulative areas alternate with mangrove swamps, coastal barriers and sandy beaches. South of 10° N. w. Accumulative banks are common, composed of material carried out from the mouth of the river. Amazon and other rivers. In the northeast of Brazil there is a sandy coast with mangroves, interrupted by river estuaries. From Cape Kalkanyar to 30° S. w. – a high, deep shore of abrasion type. To the south (off the coast of Uruguay) there is an abrasion-type coast composed of clays, loess and sand and gravel deposits. In Patagonia, the shores are represented by high (up to 200 m) cliffs with loose sediments. The coasts of Antarctica are 90% composed of ice and belong to the ice and thermal abrasion type.
Bottom relief
At the bottom of A. o. The following major geomorphological structures are distinguished: provinces: underwater continental margins (shelf and continental slope), ocean floor (deep-sea basins, abyssal plains, abyssal hill zones, uplifts, mountains, deep-sea trenches), mid-ocean. ridges.
Boundary of the continental shelf (shelf) of the A. region. takes place on Wed. 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 (northeast Brazil, Iberian Peninsula) to several hundred km (Northern Sea, Gulf of Mexico, Newfoundland Bank). In high latitudes, the shelf topography is complex and bears traces of glacial influence. Numerous uplifts (banks) are separated by longitudinal and transverse valleys or trenches. Off the coast of Antarctica there are ice shelves on the shelf. At low latitudes, the shelf surface is more leveled, especially in zones where rivers carry terrigenous material. It is crossed by transverse valleys, often turning into canyons of the continental slope.
The slope of the continental slope of the ocean is on average. 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 area of the Bahamas and the Puerto Rico Trench. Active margins are characterized by high seismicity. The surface of the slope is in some places dissected by steps, ledges and terraces of tectonic and accumulative origin and longitudinal canyons. At the foot of the continental slope there are often gentle hills high. up to 300 m and shallow underwater valleys.
In the middle part of the bottom of the A. lake. The largest mountain system of the Mid-Atlantic Ridge is located. It extends from Fr. Iceland to o. Bouvet at 18,000 km. The width of the ridge ranges from several hundred to 1000 km. The crest of the ridge runs close to the midline of the ocean, dividing it to the east. and zap. parts. On both sides of the ridge there are deep-sea basins, separated by bottom rises. In zap. parts of A. o. From north to south there are basins: Labrador (with depths of 3000–4000 m); Newfoundland (4200–5000 m); North American Basin(5000–7000 m), which includes the abyssal plains of Som, Hatteras and Nares; Guiana (4500–5000 m) with the plains of Demerara and Ceara; Brazilian Basin(5000–5500 m) with the Pernambuco abyssal plain; Argentinean (5000–6000 m). To the east parts of A. o. The basins are located: Western European (up to 5000 m), Iberian (5200–5800 m), Canary (over 6000 m), Cape Verde (up to 6000 m), Sierra Leone (approx. 5000 m), Guinean (over 6000 m). 5000 m), Angola (up to 6000 m), Cape (over 5000 m) with abyssal plains of the same name. In the south is the African-Antarctic Basin with the Weddell Abyssal Plain. The bottoms of deep-sea basins at the foot of the Mid-Atlantic Ridge are occupied by a zone of abyssal hills. The basins are separated by the Bermuda, Rio Grande, Rockall, Sierra Leone, etc. uplifts, and the Whale, Newfoundland, and other ridges.
Seamounts (isolated conical heights of 1000 m or more) at the bottom of the Arctic Ocean. concentrated primarily in the Mid-Atlantic Ridge area. In the deep sea large groups seamounts are found north of the Bermuda Islands, in the Gibraltar sector, off the north-east. ledge South. America, in the Guinea Hall. and west of South. Africa.
Deep sea trenches of Puerto Rico, Caiman(7090 m), South Sandwich Trench(8264 m) are located near island arcs. Gutter Romanche(7856 m) is a large fault. The steepness of the slopes of deep-sea trenches is from 11° to 20°. The bottom of the gutters is flat, leveled by accumulation processes.
Geological structure
A. o. arose as a result of the breakup of the Late Paleozoic supercontinent Pangea in Jurassic time. It is characterized by a sharp predominance of passive outskirts. A. o. borders on adjacent continents transform faults south of the island Newfoundland, along the north. coast of the Gulf of Guinea, along the Falkland submarine plateau and the Agulhas plateau in the south. parts of the ocean. Active margins are observed in the section. areas (in the area of the Lesser Antilles arc and the arc of the South Sandwich Islands), where subsidence occurs ( subduction) lithosphere of the A. o. The Gibraltar subduction zone, limited in extent, was identified in the Gulf of Cadiz.
In the Mid-Atlantic Ridge, the seafloor is moving apart ( spreading) and the formation of oceanic. bark at a rate of up to 2 cm per year. Characterized by high seismicity. and volcanic activity. In the north, paleospreading ridges branch off from the Mid-Atlantic Ridge into the Cape of Labrador and into the Bay of Biscay. In the axial part of the ridge there is a clearly defined rift valley, which is absent in the extreme south and in the bay. part of the Reykjanes ridge. Within its borders there is volcanic. uplifts, frozen lava lakes, basaltic lava flows in the form of pipes (pillow basalts). To the Center Metalliferous fields discovered in the Atlantic hydrotherm, many of which form hydrothermal structures at the outlet (composed of sulfides, sulfates and metal oxides); installed metalliferous sediments. At the foot of the valley slopes there are screes and landslides consisting of blocks and crushed stone of oceanic rocks. crust (basalts, gabbros, peridotites). The age of the crust within the Oligocene ridge is modern. The Mid-Atlantic Ridge divides the western zones. and east abyssal plains, where oceanic. the foundation is covered by a sedimentary cover, the thickness of which increases in the direction of the continental foothills to 10–13 km due to the appearance of more ancient horizons in the section and the supply of clastic material from land. In the same direction, the age of oceanic animals increases. crust, reaching the Early Cretaceous (north of Florida - Middle Jurassic). The abyssal plains are practically aseismic. The Mid-Atlantic Ridge is crossed by numerous. transform faults extending to adjacent abyssal plains. The thickening of such faults is observed in equatorial zone(up to 12 at 1700 km). The largest transform faults (Vima, Sao Paulo, Romanche, etc.) are accompanied by deep incisions (trenches) on the ocean floor. They reveal the entire oceanic section. crust and partly upper mantle; Protrusions (cold intrusions) of serpentinized peridotites are widely developed, forming ridges elongated along the strike of the faults. Mn. transform faults are transoceanic, or main (demarcation) faults. In A. o. there are so-called intraplate uplifts, represented by underwater plateaus, aseismic ridges and islands. They have oceanic bark of increased thickness and have ch. arr. volcanic origin. Many of them were formed as a result of the action mantle plumes; some arose at the intersection of the spreading ridge by large transform faults. K volcanic uplifts include: o. Iceland, o. Bouvet, oh. Madeira, the Canary Islands, Cape Verde, the Azores, the paired uplifts of the Sierra and Sierra Leone, the Rio Grande and the Whale Ridge, the Bermuda Uplift, the Cameroon group of volcanoes, etc. There are intraplate uplifts of non-volcanic ones. nature, which includes the underwater Rockall Plateau, separated from the British Islands by one. touching. The plateau represents microcontinent, separated from Greenland in the Paleocene. Another microcontinent that also separated from Greenland is the Hebrides in northern Scotland. The underwater marginal plateaus off the coast of Newfoundland (Great Newfoundland, Flemish Cap) and off the coast of Portugal (Iberian) were separated from the continents as a result of rifting at the end of the Jurassic - the beginning of the Cretaceous.
A. o. 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 (ca. 200 million years ago) from the Central segment. In the Triassic - Early Jurassic, oceanic spreading occurred. the bottom was preceded by continental rifting, traces of which are recorded in the form of half-grabens filled with clastic deposits in the Amer. and northern - African the edges of the ocean. At the end of the Jurassic - the beginning of the Cretaceous, the Antarctic segment began to open. In the Early Cretaceous, spreading was experienced by the South. segment in South Atlantic and the Newfoundland-Iberian segment in the North. Atlantic. The opening of the Labrador-British segment began at the end of the Early Cretaceous. At the end of the Late Cretaceous, the Labrador Sea basin arose here as a result of spreading on a side axis, which continued until the late Eocene. North and Yuzh. The Atlantic merged in the mid-Cretaceous - Eocene during the formation of the Equatorial segment.
Bottom sediments
Thickness of the modern strata. bottom sediments range from a few m in the crest zone of the Mid-Atlantic Ridge to 5–10 km in transverse fault zones (for example, in the Romanche Trench) and at the foot of the continental slope. In deep-sea basins, their thickness ranges from several tens to 1000 m. More than 67% of the area of the ocean floor (from Iceland in the north to 57–58° S) is covered with calcareous deposits formed by the remains of shells of planktonic organisms (mostly foraminifera, coccolithophoride). Their composition varies from coarse sands (at depths up to 200 m) to silts. At depths of more than 4500–4700 m, calcareous silts are replaced by polygenic and siliceous planktogenic sediments. The first ones take approx. 28.5% of the ocean floor area, lining the bottoms of basins, and are represented red deep ocean clay(deep-sea clayey silts). These sediments contain means. amounts of manganese (0.2–5%) and iron (5–10%) and very small amounts of carbonate material and silicon (up to 10%). Siliceous planktonic sediments occupy approx. 6.7% of the ocean floor area, of which the most common are diatomaceous oozes (formed by the skeletons of diatoms). They are common off the coast of Antarctica and on the southwest shelf. Africa. Radiolarian oozes (formed by the skeletons of radiolarians) are found Ch. arr. in the Angola Basin. Along the ocean coasts, on the shelf and partly on the continental slopes, terrigenous sediments of various compositions (gravel-pebble, sandy, clayey, etc.) are developed. The composition and thickness of terrigenous sediments are determined by the bottom topography, the activity of the supply of solid material from land and the mechanism of their transfer. Glacial sediments carried by icebergs are common along the coast of Antarctica. Greenland, o. Newfoundland, Labrador Peninsula; composed of poorly sorted clastic material including boulders, to a greater extent in the south of A. o. 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 localized in the Gulf of Mexico, the Caribbean Sea and the north-east. coast of Brazil; their maximum depth is 3500 m. Volcanogenic sediments are developed near volcanoes. islands (Iceland, Azores, Canaries, Cape Verde, etc.) and are represented by volcanic fragments. rocks, slag, pumice, volcanic. ashes Modern chemogenic sediments are found on the Great Bahama Bank, in the Florida-Bahamas, Antilles regions (chemogenic and chemogenic-biogenic carbonates). In the basins of North America, Brazil, and Cape Verde there are ferromanganese nodules; their composition in A. o.: 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 near the east. coast of the USA and north-west. coast of Africa. Phosphorites are common along the east. coast of A. o. – from the Iberian Peninsula to Cape Agulhas.
Climate
Due to the large extent of A. o. its waters are located in almost all natural climates. zones - from subarctic in the north to Antarctic in the south. From the north and south, the ocean is wide open to the influence of the Arctic. and Antarctic water and ice. The lowest air temperatures are observed in the polar regions. Over the coast of Greenland, temperatures can drop to –50 °C, and in the south. In parts of Cape Weddell, a temperature of –32.3 °C was recorded. In the equatorial region, the air temperature is 24–29 °C. The pressure field over the ocean is characterized by a consistent change of stable large pressure formations. There are anticyclones over the ice domes of Greenland and Antarctica, in the temperate latitudes of the North. and Yuzh. hemispheres (40–60°) - cyclones, in lower latitudes - anticyclones, separated by a zone of low pressure at the equator. This pressure structure maintains tropical temperatures. and equatorial latitudes, stable winds are east. directions (trade winds), in moderate latitudes - strong winds from the west. directions that were named by sailors. "Roaring Forties". Strong winds are also typical for the Bay of Biscay. In the equatorial region, the interaction of northern. and south pressure systems lead to frequent tropical cyclones (tropical hurricanes), the greatest activity of which is observed from July to November. Horizontal dimensions tropical. cyclones up to several hundred km. 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. Low pressure areas in temperate and equatorial latitudes often experience precipitation and heavy cloud cover. So, St. falls on the equator. 2000 mm of precipitation per year, in temperate latitudes - 1000–1500 mm. In areas of high pressure (subtropics and tropics), precipitation decreases to 500–250 mm per year, and in areas adjacent to the desert coasts of Africa and in the South Atlantic High, to 100 mm or less per year. In areas where warm and cold currents meet, fogs are frequent, for example. in the Newfoundland Bank area and into the hall. La Plata.
Hydrological regime
Rivers and water balance With. To the pool of A. o. Every year 19,860 km 3 of water is carried out by rivers, this is more than into any other ocean (about 45% of the total flow into the World Ocean). The largest rivers (with an annual flow of over 200 km 3): 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 of the A. o. negative: evaporation from its surface (100–125 thousand km 3 / year) significantly exceeds atmospheric precipitation (74–93 thousand km 3 / year), river and underground runoff (21 thousand km 3 / year) and melting of ice and icebergs in the Arctic and Antarctic (approx. 3 thousand km 3 /year). The water balance deficit is compensated by the influx of water, ch. arr. from the Pacific Ocean, through the Drake Passage with the current of the Western Winds, 3,470 thousand km 3 /year comes, and from the A. o. in Quiet approx. only 210 thousand km 3 /year goes away. From the Arctic Ocean approx. through numerous straits in A. o. 260 thousand km 3 /year and 225 thousand km 3 /year are received from the Atlantic. water flows back to the Arctic approx. Water balance with Indian ca. negative, in Indian approx. with the flow of the Western Winds, 4976 thousand km 3 /year are carried out, and return with the Coastal Antarctic Sea. current, deep and bottom waters only 1692 thousand km 3 /year.
Temperature regime m. Wed. The temperature of ocean waters as a whole is 4.04 °C, and that of surface waters is 15.45 °C. The distribution of water temperature on the surface is asymmetrical relative to the equator. Strong influence of the Antarctic. water leads to the fact that the surface waters of the South. hemisphere is almost 6 °C colder than the Northern hemisphere, the warmest waters of the open part of the ocean (thermal equator) are between 5 and 10 ° N. sh., i.e. shifted to the north of the geographic. equator. Features of large-scale water circulation lead to the fact that the water temperature on the surface near the west. The ocean shores are approximately 5 °C higher than those on the eastern shores. The warmest water temperature (28–29 °C) on the surface is in the Caribbean Sea and Gulf of Mexico. in August, the lowest is off the coast of the island. Greenland, o. Baffin Island, Labrador and Antarctica peninsulas, south of 60°, where even in summer the water temperature does not rise above 0 °C. Temperature of water in the layer Ch. thermocline (600–900 m) is approx. 8–9 °C, deeper, in intermediate waters, falls on Wed. up to 5.5 °C (1.5–2 °C in Antarctic intermediate waters). In deep waters, water temperature on avg. 2.3 °C, in the bottom 1.6 °C. At the very bottom, the water temperature increases slightly due to geothermal conditions. heat flow.
Salinity. In the waters of A. o. contains approx. 1.1×10 16 t salts. Wed. The salinity of the waters of the entire ocean is 34.6‰, and the salinity of surface waters is 35.3‰. The highest salinity (over 37.5‰) is observed on the surface in the subtropics. areas where the evaporation of water from the surface exceeds its supply with precipitation, the lowest (6–20‰) in the mouth areas of large rivers flowing into the ocean. From the subtropics to high latitudes, surface salinity decreases to 32–33‰ under the influence of precipitation, ice, river and surface runoff. In temperate and tropical areas max. salinity values are on the surface; an intermediate minimum of salinity is observed at depths of 600–800 m. Northern waters. parts of A. o. characterized by a deep maximum salinity (more than 34.9‰), which is formed by highly saline Mediterranean waters. Deep waters of A. o. have a salinity of 34.7–35.1‰ and a temperature of 2–4 °C, 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 A. o. temperature is of greater importance in the formation of the water density field. Water with lowest density located in the equatorial and tropical. areas with high water temperatures and strong influence flow of rivers such as the Amazon, Niger, Congo, etc. (1021.0–1022.5 kg/m3). To the south In the northern part of the ocean, the density of surface water increases to 1025.0–1027.7 kg/m 3 , in the northern part – to 1027.0–1027.8 kg/m 3 . Density of deep waters of the A. o. 1027.8–1027.9 kg/m3.
Ice regime in the north. parts of A. o. First-year ice is formed ch. arr. in internal seas of temperate latitudes, multi-year ice is carried out of the Arctic approx. The boundary of the distribution of ice cover in the north. parts of A. o. changes significantly; in winter, pack ice can reach decomposition. years 50–55° N. w. There is no ice in summer. Antarctic border multi-year ice in winter it passes at a distance of 1600–1800 km from the coast (approximately 55° S); in summer (February–March) ice is found only in coastal strip Antarctica and Weddell Cape. Basic Suppliers of icebergs are the ice sheets and ice shelves of Greenland and Antarctica. total weight icebergs coming from the Antarctic. glaciers, estimated at 1.6×10 12 tons per year, base. their source is the Filchner Ice Shelf in Weddell Cape. From the glaciers of the Arctic to the Arctic. icebergs with a total mass of 0.2–0.3×10 12 tons per year are received, mainly from the Jakobshavn glacier (in the area of Disko Island off the western coast of Greenland). Wed. life expectancy of the arctic icebergs approx. 4 years, slightly more Antarctic. The limit of iceberg distribution in the north. parts of the ocean 40° N. sh., but in dep. in cases they were observed up to 31° N. w. To the south parts of the border passes at 40° south. sh., to the center. part of the ocean and at 35° south. w. to the west and east periphery.
Currents I. Water circulation of the A. o. is divided into 8 quasi-stationary oceanic. gyres located almost symmetrically relative to the equator. From low to high latitudes in the North. and Yuzh. hemispheres are tropical. anticyclonic, tropical cyclonic, subtropical anticyclonic, subpolar cyclonic. oceanic gyres. Their boundaries, as a rule, are ch. oceanic currents. A warm current originates near the Florida Peninsula Gulf Stream. Absorbing warm waters Antillean Current And Florida Current, The Gulf Stream heads northeast and at high latitudes splits into several branches; the most significant of them are Irminger current, which transports warm waters to Davis Strait, the North Atlantic Current, Norwegian Current, going to the Norwegian Cape and further to the northeast, along the coast of the Scandinavian Peninsula. To meet them from Davis Strait. it comes out cold Labrador Current, the waters of which can be traced off the coast of America to almost 30° N. w. From the Danish Strait. The cold East Greenland Current flows into the ocean. At low latitudes, A. o. warm air flows from east to west Northern trade wind currents And Southern trade wind currents, between them, approximately 10° N. sh., from west to east there is an Intertrade Countercurrent, which is active Ch. arr. in summer in the North. hemispheres. Separates from the Southern Trade Wind Currents Brazilian Current, which runs from the equator to 40° S. w. along the coast of America. North the branch of the Southern Trade Wind Currents forms Guiana Current, which is directed from south to northwest until it connects with the waters of the Northern Trade Wind Currents. Off the coast of Africa from 20° N. w. The warm Guinea Current passes to the equator; in the summer, the Intertrade Countercurrent is connected to it. To the south parts of A. o. crosses the cold Western Winds current(Antarctic Circumpolar Current), which is part of the Arctic Ocean. through the strait Drake, descends to 40° S. w. and goes out to Indian approx. south of Africa. Separated from it is the Falkland Current, which reaches along the coast of America almost to the mouth of the river. Parana, Benguela Current, running along the coast of Africa almost to the equator. Cold Canary Current passes from north to south - from the shores of the Iberian Peninsula to the Cape Verde Islands, where it turns into the Northern Trade Wind Currents.
Deep circulation in e. Deep circulation and structure of waters of the A.O. are formed as a result of changes in their density during cooling of waters or in zones of mixing of decomposed waters. origin, where density increases as a result of mixing water with decomposition. salinity and temperature. Subsurface waters are formed in the 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 the 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. character. Deep waters are formed in high northern latitudes. and south parts of the ocean. Waters formed in the Antarctic. area, have the highest density and spread from south to north in the bottom layer, their temperature varies from negative (in high southern latitudes) to 2.5 °C, salinity 34.64–34.89‰. Waters formed in the high north. 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. Broker substantiated the scheme of planetary interoceanic transfer of energy and matter, which was called. “global conveyor belt” or “global thermohaline circulation of the World Ocean”. According to this theory, the relatively salty North Atlantic. waters reach the coast of Antarctica, mix with supercooled shelf water and, passing through the Indian Ocean, end their journey to the north. parts of the Pacific Ocean.
Tides and waves e. Tides in A. o. preim. semi-daily allowance. Tidal wave height: 0.2–0.6 m in the open part of the ocean, a few cm in the Black Sea, 18 m in the bay. Fundy (the northern part of the Gulf of Maine in North America) is 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. Quite rarely (once every 15–20 years) high waves have been observed. 22–26 m.
Flora and fauna
The large extent of the Arctic region, the diversity of climates. conditions, that is. influx of fresh water and large upwellings provide a variety of living conditions. In total, the ocean is inhabited by approx. 200 thousand species of plants and animals (of which about 15,000 species of fish, about 600 species of cephalopods, about 100 species of whales and pinnipeds). Life is distributed very unevenly in the ocean. There are three main ones. type of zonation of life distribution in the ocean: latitudinal, or climatic, vertical and circumcontinental. 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 the tropics. latitude to high.
Planktonic organisms (phytoplankton and zooplankton) are the basis of the food chain in the ocean, mainly. a lot of them live in the upper zone of the ocean, where light penetrates. The highest biomass of plankton is in high and temperate latitudes during spring-summer flowering (1–4 g/m3). During the year, biomass can change 10–100 times. Basic species of phytoplankton - diatoms, zooplankton - copepods and euphausids (up to 90%), as well as chaetognaths, hydromedusas, ctenophores (in the north) and salps (in the south). At low latitudes, plankton biomass varies from 0.001 g/m 3 in the centers of anticyclonic. gyres up to 0.3–0.5 g/m 3 in the Gulf of Mexico and Guinea. Phytoplankton is represented by Ch. arr. coccolithines and peridineans, the latter can develop in huge quantities in coastal waters, causing catastrophes. "red tide" phenomenon. Zooplankton at low latitudes is represented by copepods, chaetognaths, hyperids, hydromedusae, siphonophores and other species. There are no clearly defined dominant species of zooplankton at low latitudes.
The benthos is represented by large algae (macrophytes), which b. h. grow on the bottom of the shelf zone to a depth of 100 m and cover approx. 2% of the total ocean floor area. The development of phytobenthos is observed in places where there are suitable conditions - soils suitable for attachment to the bottom, the absence or moderate speeds of bottom currents, etc. In high latitudes, the A. o. basic part of the phytobenthos consists of kelp and red algae. In the temperate zone of the north. parts of the A. region, along the American and European coasts, are brown algae (fucus and ascophyllum), kelp, desmarestia, and red algae (furcellaria, ahnfeltia, etc.). Zostera is common on soft soils. In the temperate and cold zones of the south. parts of A. o. Brown algae predominate. In the tropics 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 Cape, where floating macrophytes (mainly three species of algae of the genus Sargassum) form clusters on the surface in the form of ribbons from 100 m to several m long. kilometers.
Most of the nekton biomass (actively swimming animals - fish, cephalopods and mammals) consists of fish. The largest number of species (75%) live in the shelf zone; with depth and distance from the coast, the number of species decreases. Characteristic for cold and temperate zones: from fish – decomposition. species of cod, haddock, pollock, herring, flounder, catfish, conger eel, etc., herring and arctic sharks; among mammals – pinnipeds (harp seal, hooded seal, etc.), decomp. species of cetaceans (whales, sperm whales, killer whales, pilot whales, bottlenose whales, etc.).
There is great similarity between the faunas of temperate and high latitudes of both hemispheres. At least 100 species of animals are bipolar, that is, they are characteristic of both temperate and high zones. For tropical zones of A. o. characteristic: from fish – decomposition. sharks, flying fish, sailboats, etc. species of tuna and glowing anchovies; among animals - sea turtles, sperm whales, river dolphin; Cephalopods are also numerous - various. species of squid, octopus, etc.
Deep-sea fauna (zoobenthos) A. o. represented by sponges, corals, echinoderms, crustaceans, mollusks, etc. worms.
History of the study
There are three stages of research into A. o. The first is characterized by the establishment of the boundaries of the ocean and the discoveries of its individual objects. AT 12- 5th centuries BC e. the Phoenicians, Carthaginians, Greeks and Romans left descriptions of sea travels and the first nautical charts. Their voyages reached the Iberian Peninsula, England and the mouth of the Elbe. In the 4th century. BC e.Piteas(Pytheas) while sailing to the North. Atlantic determined the coordinates of a number of points and described tidal phenomena in the Arctic Ocean. By the 1st century. n. e. There are references to the Canary Islands. In the 9th–10th centuries. Normans (RowdyEirik and his son Leif Eirikson) crossed the ocean, visited Iceland, Greenland, Newfoundland and explored the shores of the North. America under 40°s. w. In the eraGreat geographical discoveries(mid 15th – mid 17th centuries) seafarers (mostly Portuguese and Spanish) explored the route to India and China along the coast of Africa. The most outstanding voyages during this period were carried out by the Portuguese B.Diashem(1487), by the Genoese H.Columbus(1492–1503), Englishman J.Cabot(1497) and the Portuguese Vasco daGama(1498); for the first time they are trying to measure the depths of open parts of the ocean and the speed of surface currents. First bathymetric map (depth map) of A. o. was compiled in Spain in 1523. In 1520 F.Magellanfirst passed from A. o. in Quiet approx. the strait later named after him. In the 16th–17th centuries. The Atlantic is being intensively studied. North coast America (English J.Davis, 1576–78, G. Hudson, 1610, U. Baffin, 1616, and other navigators whose names can be found on the ocean map). The Falkland Islands were discovered in 1591–92. South shores of A. o. - the continent of Antarctica - were discovered and first described by Russian. Antarctic expedition F.F.Bellingshausen and M.P. Lazarevin 1819–21. This completed the study of the ocean's boundaries.
The second stage is characterized by the study of physics. properties of ocean waters, temperature, salinity, currents, etc. In 1749, the Englishman G. Ellis made the first measurements of temperature at various depths, repeated by the Englishman J. Cook(1772), Swiss O. Saussure(1780), Russian I.F. Krusenstern(1803), etc. In the 19th century. A. o. becomes a testing ground for testing new methods for exploring depths, new equipment and new approaches to organizing work. For the first time, bathometers, deep-sea thermometers, thermal depth gauges, deep-sea trawls and dredges were used. Of the most significant expeditions, Russian can be noted. sailing on the ships "Rurik" (1815–18) and "Enterprise" (1823–26) under the leadership of O.E.Kotzebue(1815–18); English on Erebus and Terror under the direction of J.K.Rossa(1840–43); Amer. on the "Arctic" under the leadership of M.F.Mori(1856). Real comprehensive oceanographic Ocean exploration began with an expedition to English. corvette« Challenger" led by W. Thomson (1872–76). The significant expeditions that followed were carried out on the ships Gazelle (1874–76), Vityaz (1886–89), Valdivia (1898–99), and Gauss (1901–03). From 1885 to 1922, he made a great contribution to the study of A. o. contributed by Prince Albert I of Monaco, who organized and led expeditionary research on the yachts “Irendel”, “Princess Alice”, “Irendel II”, “Princess Alice II” in the north. parts of the ocean. During these same years, he organized the Oceanographic Museum in Monaco. Since 1903, work began on “standard” sections in the North Atlantic under the leadership of the International Council for the Exploration of the Sea (ICES), the first international oceanographic study. 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, and Atlantis. In 1931, the International Council of Scientific Unions (ICSU) was formed, which is still active today, organizing and coordinating ocean research.
After World War II, echo sounders began to be widely used to study the ocean floor. This made it possible to obtain a real picture of the topography of the ocean floor. In the 1950s–70s. complex geophysical surveys were carried out. and geological research of A. o. and the features of the topography of its bottom, tectonics, and the structure of the sedimentary strata were established. Many large forms of bottom relief have been identified (underwater ridges, mountains, trenches, fault zones, extensive basins and uplifts), and geomorphological data have been compiled. and tectonic cards. Unique results were obtained from the international deep ocean drilling program IODP (1961–2015, ongoing).
The third stage of ocean research is aimed mainly at studying its role in global processes of matter and energy transfer and its influence on climate formation. Complexity and wide range research work demanded broad international cooperation. In the coordination and organization of international research big role They are played by the Scientific Committee for Ocean Research (SCOR), formed in 1957, the Intergovernmental Oceanographic Commission of UNESCO (IOC), operating since 1960, and other international organizations. In 1957–58, extensive work was carried out within the framework of the first International Geophysical Year (IGY). Subsequently, large international projects were aimed at studying individual parts of the A.O., for example, EQUALANT I–III (1963–64), Polygon-70 (1970), SIKAR (1970–75), POLYMODE (1977–78 ), and A. o. as parts of the World Ocean, for example TOGA (1985–89), GEOSECS (1973–74), WOCE (1990–96), etc. During these projects, the features of water circulation of various scales, distribution and composition of suspended matter were studied; the role of the ocean in the global carbon cycle and many others. other questions. In the end 1980s owls deep-sea vehicles"World» The unique ecosystems of geothermal regions of the ocean rift zone were studied. If at the beginning 80s it was ok. 20 international projects ocean exploration, then by the 21st century. St. 100. The largest programs:« International Geosphere-Biosphere Program» (since 1986, 77 countries participate), it includes projects« Dynamics of global ocean ecosystems» (GLOBES, 1995–2010), "Global flows of matter in the ocean» (JGOFS, 1988–2003), " Land–ocean interaction in the coastal zone» (LOICZ), Integrated Marine Biogeochemistry and Ecosystem Research (IMBER), Land-Ocean Interactions in the Coastal Zone (LOICZ, 1993–2015), Surface Ocean-Lower Atmosphere Interaction Study (SOLAS, 2004–15, ongoing),« World Program climate research» (WCRP, since 1980, 50 countries participate), International study of biogeochemical cycles and large-scale distribution of trace elements and their isotopes in the marine environment (GEOTRACES, 2006–15, ongoing) and many others. etc. The Global Ocean Observing System (GOOS) is being developed. One of the main projects of the WCRP was the Climate and Ocean: Volatility, Predictability and Variability program (CLIVAR, since 1995), which was based on the results of TOGA and WOCE. Ross. For many years, scientists have been conducting expeditionary studies of exchange processes at the border of the Arctic Ocean. and the Arctic Ocean, circulation in the Drake Passage, distribution of cold Antarctic waters along deep-sea faults. Operating since 2005 international program"ARGO", in which observations are carried out by autonomous sounding instruments throughout the World Ocean (including the Arctic Ocean), and the results are transmitted via artificial satellites Lands to data centers.
In November 2015, Russia sailed from Kronstadt to the shores of Antarctica for the first time in the last 30 years. research vessel Baltic Fleet"Admiral Vladimirsky". It made a journey over 34 thousand nautical miles. miles. Along the route, hydrographic, hydrological, hydrometeorological and radio navigation studies were carried out, information was collected to correct marine navigation charts, manuals and navigation manuals. Having rounded the southern tip of the African continent, the ship entered the marginal seas of Antarctica. He moored near the tower. Progress station, scientists exchanged data with station staff on monitoring ice conditions, melting Arctic ice, and weather. The expedition ended on April 15, 2016. In addition to the crew, hydrograph specialists from the 6th Atlantic Oceanographic Division took part in the expedition. hydrographic expeditions services of the Baltic Fleet, employees of the Russian Federation. state hydrometeorological University, the Institute of the Arctic and Antarctic, etc. Work has been completed on the creation of the third part of the Oceanographic Atlas WOCE (The World Ocean Circulation Experiment), dedicated to the Atlantic Ocean, the presentation of which took place in February 2015 at the IO RAS. P. P. Shirshova.
Economic use
A. o. occupies the most important place in the global economy among other oceans of our planet. Human use of the Arctic Ocean, like other seas and oceans, is based on several principles. directions: transport and communications, fishing, mineral extraction. resources, energy, recreation.
Transport
Already for 5 centuries A. o. takes a leading role in maritime transport. With the opening of the Suez (1869) and Panama (1914) canals, short sea routes between the Atlantic, Indian and Pacific oceans. To the share of A. o. account for approx. 3/5 of the cargo turnover of world shipping, in con. 20th century up to 3.5 billion tons of cargo were transported across its waters per year (according to IOC data). OK. 1/2 of the transport volume is oil, gas and petroleum products, followed by general cargo, then iron ore, grain, coal, bauxite and alumina. Ch. The direction of transportation is North Atlantic, which passes between 35–40° N. w. and 55–60° N. w. Basic shipping routes connect port cities in Europe, the USA (New York, Philadelphia) and Canada (Montreal). This direction is adjacent to the Norwegian, Northern and inland sea routes. seas of Europe (Baltic, Mediterranean and Black). Transported to main raw materials (coal, ores, cotton, timber, etc.) and general cargo. Dr. important transportation directions - South Atlantic: Europe - Central (Panama, etc.) and South America (Rio de Janeiro, Buenos Aires); East Atlantic: Europe - southern Africa (Cape Town); Western-Atlantic: North. America, South America - South Africa. Before the reconstruction of the Suez Canal (1981) b. including oil tankers from the Indian basin approx. was forced to go around Africa.
Passenger transportation occupies an important place in the airport. since the 19th century, when mass emigration from the Old World to America began. The first steam-sailing ship, the Savannah, crossed the A.O. for 29 days in 1819. At the beginning. 19th century A Blue Ribbon prize has been established for passenger ships that can cross the ocean the fastest. This prize was awarded, for example, to such famous liners as the Lusitania (4 days and 11 hours), the Normandy (4 days and 3 hours), and the Queen Mary (4 days and 3 minutes). The last time the Blue Ribbon was awarded to Amer. to the United States liner in 1952 (3 days and 10 hours). In the beginning. 21st century The flight duration of a passenger airliner between London and New York is 5–6 days. Max. passenger transportation through A. o. occurred in 1956–57, when more than 1 million people were transported per year; in 1958, the volume of passenger transportation by air was equal to sea transportation, and then everything went on. h. passengers give preference air transport(record flight time of the supersonic Concorde airliner on the route New York - London - 2 hours 54 minutes). The first non-stop flight through A. O. committed 14–15.6.1919 English. pilots J. Alcock and A. W. Brown (Newfoundland Island - Ireland Island), the first non-stop flight through A.O. alone (from continent to continent) 5/20–21/1927 – Amer. pilot C. Lindberg (New York - Paris). In the beginning. 21st century almost the entire flow of passengers through the airport. served by aviation.
Connection
In 1858, when there was no radio communication between the continents, through the A. o. The first telegraph cable was laid. K con. 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. St. acted at the bottom of the ocean. 10 telephone lines. In 1988, the first transatlantic fiber-optic communication line was laid, at the beginning of the 21st century. 8 lines operate.
Fishing
A. o. considered the most productive ocean, his biological resources are most intensively exploited by humans. In A. o. Fishing and seafood production account for 40–45% of the total world catch (approx. 25% of the world). Most of the catch (up to 70%) consists of herring fish (herring, sardines, etc.), cod fish (cod, haddock, hake, whiting, pollock, navaga, etc.), flounder, halibut, and sea bass. Extraction of mollusks (oysters, mussels, squid, etc.) and crustaceans (lobsters, crabs) approx. 8%. According to FAO estimates, the annual catch of fish products in the A. region. is 85–90 million tons, but for most fishing areas of the Atlantic, fish catches reached mid. 1990s its maximum and increasing it is undesirable. The traditional and most productive fishing area is north-east. part of the Arctic Ocean, including the North and Baltic seas (mainly herring, cod, flounder, sprats, mackerel). In the north-west area of the ocean, on the Newfoundland banks, cod, herring, flounder, squid, etc. have been caught for many centuries. To the center. parts of A. o. There is a catch of sardines, horse mackerel, mackerel, tuna, etc. In the south, on the Patagonian-Falkland shelf, which is elongated in latitude, there is fishing for both warm-water species (tuna, marlin, swordfish, sardines, etc.) and cold-water species (blue whiting, hake , notothenia, toothfish, etc.). Off the coast of the west. and southwest African catch of sardine, anchovy and hake. In the Antarctic region In the ocean area, planktonic crustaceans (krill), marine mammals, and fish - notothenia, toothfish, silverfish, etc. are of commercial importance. Until mid. 20th century in high latitude northern and south areas of the ocean, active fishing was carried out. species of pinnipeds and cetaceans, but in recent decades it has sharply declined due to biological depletion. resources and thanks to environmental measures, including intergovernmental ones. agreements to limit their production.
Mineral resources
The development of the mineral is becoming more and more active. riches of the ocean floor. Oil and combustible gas deposits have been studied more fully, the first mentions of their exploitation in the Arctic basin. date back to 1917, when industrial oil production began. scale in the east. parts of the Maracaibo lagoon (Venezuela). Largest centers marine production: Venezuelan Gulf, Maracaibo Lagoon ( Maracaiba oil and gas basin), Mexican Hall. ( Gulf of Mexico oil and gas basin), hall. Pariah ( Orinoco oil and gas basin), Brazilian shelf (Sergipe-Alagoas oil and gas basin), Gulf of Guinea. ( Gulf of Guinea oil and gas basin), Northern metro station ( North Sea oil and gas bearing area) etc. Placer deposits of heavy minerals are common along many coasts. The largest developments of placer deposits of ilmenite, monocyte, zircon, and rutile are carried out off the coast of Florida. Similar deposits are located in the Gulf of Mexico, near the east. coast of the USA, as well as Brazil, Uruguay, Argentina and the Falkland Islands. On the shelf southwest. In Africa, coastal marine diamond deposits are being developed. Gold placers were discovered off the coast of Nova Scotia at depths of 25–45 m. In A. o. One of the world's largest iron ore deposits, Wabana (in Conception Bay off the coast of Newfoundland), has been explored; iron ore is also mined off the coast of Finland, Norway and France. Coal deposits are being developed in the coastal waters of Great Britain and Canada, extracting it in mines located on land, the horizontal workings of which go under the seabed. On the shelf of the Gulf of Mexico. large sulfur deposits are being developed Gulf of Mexico sulfur province. In the coastal zone of the ocean, sand and gravel are mined for construction and glass production. On the shelf east. coast of the USA and western On the coast of Africa, phosphorite-bearing sediments have been explored, but their development is not yet profitable. The total mass of phosphorites on the continental shelf is estimated at 300 billion tons. Large fields of ferromanganese nodules have been found at the bottom of the North American Basin and on the Blake Plateau, their total reserves in the Arctic Ocean. are estimated at 45 billion tons.
Recreational resources
From the 2nd half. 20th century great importance for the economy of coastal countries is the use of recreational resources of the ocean. Old resorts are being developed and new ones are being built. Since the 1970s ocean liners intended only for cruises are laid down, they are distinguished big sizes(displacement 70 thousand tons or more), increased level comfort and relative low speed. Basic routes of cruise ships A. o. – Mediterranean and Caribbean Seas and the Mexican Hall. From the end 20 – beginning 21st centuries Scientific tourism and extreme cruise routes are being developed, mainly in the high latitudes of the North. and Yuzh. hemispheres. In addition to the Mediterranean and Black Sea basins, the main resort centers are located in the Canary Islands, Azores, Bermuda, the Caribbean and the Gulf of Mexico.
Energy
Energy sea tides A. o. is estimated at approximately 250 million kW. In the Middle Ages, mills and sawmills were built in England and France using tidal waves. At the mouth of the river Rance (France) operates a tidal power plant. The use of hydrothermal energy from the ocean (temperature differences in surface and deep waters) is also considered promising; a hydrothermal station operates on the coast of Côte d’Ivoire.
Port cities
On the shores of A. o. most of the world's major ports are located: in Western Europe - Rotterdam, Marseille, Antwerp, London, Liverpool, Genoa, Le Havre, Hamburg, Augusta, Southampton, Wilhelmshaven, Trieste, Dunkirk, Bremen, Venice, Gothenburg, Amsterdam, Naples, Nantes-St. Nazer, Copenhagen; all in. 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, Abidjan, Cape Town. Ross. port cities do not have direct access to the Arctic Ocean. and are located on the banks of the inland. seas belonging to its basin: St. Petersburg, Kaliningrad, Baltiysk (Baltic Sea), Novorossiysk, Tuapse (Black Sea).
ATLANTIC OCEAN (Latin name Mare Atlanticum, Greek?τλαντ?ς - designated the space between the Strait of Gibraltar and the Canary Islands, the entire 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.
Physico-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 Davis Strait and along the coast of Greenland to Cape Brewster, through the Denmark Strait to Cape Reydinupur on the island of Iceland, along its coast to Cape Gerpir (Terpir), then to the Faroe Islands, then to the Shetland Islands and along 61° north latitude to the coast of the Scandinavian Peninsula. In the east, the Atlantic Ocean is limited by the shores of Europe and Africa, in the west by the shores of North America and South America. The border of the Atlantic Ocean with the Indian Ocean is drawn along a line running from Cape Agulhas along the meridian of 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 Sterneck. The South Atlantic Ocean is sometimes called the Atlantic sector of the Southern Ocean, drawing the boundary along the subantarctic convergence zone (approximately 40° south latitude). Some works propose dividing the Atlantic Ocean into the North and South Atlantic Oceans, but it is more common to view it as a single ocean. The Atlantic Ocean is the most biologically productive of the oceans. It contains the longest underwater ocean ridge- The Mid-Atlantic Ridge, the only sea that does not have solid shores, limited by currents, is 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 extends from north to south for almost 15 thousand km, its smallest width is about 2830 km in the equatorial part, the greatest - 6700 km (along the parallel of 30° north latitude). The area of the Atlantic Ocean with seas, bays and straits is 91.66 million km2, without them - 76.97 million km2. 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 (Puerto Rico Trench). The most easily accessible shelf zone of the ocean (with depths 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 significantly 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 seas and bays, more than 70% is the ocean bed (abyssal zone). See the map.
Seas. In the Atlantic Ocean basin there are numerous seas, which are divided into: internal - Baltic, Azov, Black, Marmara and Mediterranean (in the latter, in turn, the seas are distinguished: Adriatic, Alboran, Balearic, Ionian, Cyprus, Ligurian, Tyrrhenian, Aegean) ; interisland - Irish and inland seas west coast Scotland; marginal - Labrador, North, Sargasso, 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, Mexico, Maine, St. 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 Atlantic Ocean islands 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, Tierra del Fuego archipelago (Terra del Fuego, Oste, Navarino ), Marajo, Sicily, Sardinia, Lesser Antilles, Falklands (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 etc.
Shores. The coastline in the northern part of the Atlantic Ocean is strongly indented (see also the article Coast), almost all large inland seas and bays are located here; in the southern part of the Atlantic Ocean the shores are slightly indented. The coasts of Greenland, Iceland and the coast of Norway are predominantly of tectonic-glacial dissection of the fjord and fiard types. Further south, in Belgium, they give way to sandy, shallow shores. The coast of Flanders is mainly of artificial origin (coastal dams, polders, canals, etc.). The shores of the island of Great Britain and the island of Ireland are abrasive bays, high limestone cliffs alternate with sandy beaches and muddy drainages. The Cherbourg Peninsula has rocky shores and sandy and gravel beaches. The northern coast of the Iberian Peninsula is composed of rocks; to the south, off the coast of Portugal, sandy beaches predominate, often enclosing lagoons. Sandy beaches also line the shores of Western Sahara and Mauritania. To the south of Cape Zeleny there are leveled abrasion-bay shores with mangroves. The western part 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 coast with a significant number of spits and lagoons. In southwestern Africa there are accumulative, less often abrasion-bay shores with extensive sandy beaches. The coasts of southern Africa are of abrasion-bay type and are composed of hard crystalline rocks. The coasts of Arctic Canada are abrasive, with high cliffs, glacial deposits and limestones. In eastern Canada and the northern Gulf of St. Lawrence there are intensely eroded cliffs of limestone and sandstone. There are wide beaches in the west and south of the Gulf of St. Lawrence. On the shores of the Canadian provinces of Nova Scotia, Quebec, and Newfoundland there are outcrops of hard crystalline rocks. From approximately 40° north latitude to Cape Canaveral in the USA (Florida) there is an alternation of leveled accumulative and abrasive types of shores composed of loose rocks. The Gulf Coast is low-lying, bordered by mangroves in Florida, sandbars in Texas, and deltaic shores in Louisiana. On the Yucatan Peninsula there are cemented beach sediments, to the west of the peninsula there is an alluvial-marine plain with coastal levees. 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 common, composed of material carried from the mouth of the Amazon River and other rivers. In the northeast of Brazil there is a sandy coast with mangroves, interrupted by river estuaries. From Cape Kalkanyar to 30° south latitude there is a high, deep coast of abrasion type. To the south (off the coast of Uruguay) there is an abrasion-type coast composed of clays, loess and sand and gravel deposits. In Patagonia, the shores are represented by high (up to 200 m) cliffs with loose sediments. The coasts 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, abyssal hill zones, 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 (northeast Brazil, Iberian Peninsula) to several hundred km (North Sea, Gulf of Mexico, Newfoundland Bank). In high latitudes, the shelf topography is complex and bears traces of glacial influence. Numerous uplifts (banks) are separated by longitudinal and transverse valleys or trenches. Off the coast of Antarctica there are ice shelves on the shelf. At low latitudes, the shelf surface is more leveled, especially in zones where rivers carry terrigenous material. 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° (regions 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 area of the Bahamas and the Puerto Rico Trench. Active margins are characterized by high seismicity. The surface of the slope is in some places dissected by steps, ledges 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 Atlantic Ocean floor is the largest mountain system of the Mid-Atlantic Ridge. It extends from Iceland to Bouvet Island for 18,000 km. The width of the ridge ranges from several hundred to 1000 km. The crest of 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-sea basins, separated by bottom rises. In the western part of the Atlantic Ocean, from north to south, basins are distinguished: Labrador (with depths of 3000-4000 m); Newfoundland (4200-5000 m); North American Basin (5000-7000 m), which includes the abyssal plains of Som, Hatteras and Nares; Guiana (4500-5000 m) with the plains of Demerara and Ceara; Brazilian Basin (5000-5500 m) with the abyssal plain of Pernambuco; Argentinean (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 ), Angola (up to 6000 m), Cape (over 5000 m) with the abyssal plains of the same name. In the south is the African-Antarctic Basin with the Weddell Abyssal Plain. The bottoms of deep-sea basins at the foot of the Mid-Atlantic Ridge are occupied by a zone of abyssal hills. The basins are separated by the Bermuda, Rio Grande, Rockall, Sierra Leone, etc. uplifts, and the Whale, Newfoundland, and other ridges.
Seamounts (isolated conical heights 1000 m or more high) on the floor of the Atlantic Ocean are concentrated primarily in the Mid-Atlantic Ridge zone. In the deep sea, large groups of seamounts occur north of Bermuda, in the Gibraltar sector, off the northeastern bulge of South America, in the Gulf of Guinea and west of South Africa.
The deep-sea trenches of Puerto Rico, Cayman (7090 m), and the South Sandwich Trench (8264 m) are located near island arcs. The Romanche Trench (7856 m) is a large fault. The steepness of the slopes of deep-sea trenches is from 11° to 20°. The bottom of the gutters is flat, leveled by accumulation processes.
Geological structure. The Atlantic Ocean arose from the breakup of the late Paleozoic supercontinent Pangea during Jurassic times. It is characterized by a sharp predominance of passive outskirts. The Atlantic Ocean borders adjacent continents along transform faults south of the island 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 certain areas (in the area of the Lesser Antilles arc and the arc of the South Sandwich Islands), where subsidence with underthrust (subduction) of the Atlantic Ocean crust occurs. The Gibraltar subduction zone, limited in extent, was identified in the Gulf of Cadiz.
In the Mid-Atlantic Ridge, the seafloor is moving apart (spreading) and oceanic crust is forming at a rate of up to 2 cm per year. Characterized by high seismic and volcanic activity. In the north, paleospreading ridges branch off from the Mid-Atlantic Ridge 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 throughout most of the Reykjanes Range. Within its boundaries are volcanic uplifts, frozen lava lakes, and basaltic lava flows in the form of pipes (pillow basalts). In the Central Atlantic, fields of metal-bearing hydrotherms have been discovered, many of which form hydrothermal structures at the outlet (composed of sulfides, sulfates and metal oxides); metalliferous sediments have been established. At the foot of the valley slopes there are screes and landslides consisting of blocks and crushed rocks of 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 foundation is covered 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 supply of clastic material from land. In the same direction, the age of the oceanic crust increases, reaching the Early Cretaceous (north of Florida - Middle Jurassic). The abyssal plains are practically aseismic. The Mid-Atlantic Ridge is crossed by numerous transform faults that extend into adjacent abyssal plains. The concentration of such faults is observed in the equatorial zone (up to 12 per 1700 km). The largest transform faults (Vima, Sao Paulo, Romanche, etc.) are accompanied by deep incisions (trenches) on the ocean floor. They reveal the entire section of the oceanic crust and part of the upper mantle; Protrusions (cold intrusions) of serpentinized peridotites are widely developed, forming ridges elongated along the strike of the faults. Many transform faults are transoceanic, or main (demarcation) faults. In the Atlantic Ocean there are so-called intraplate uplifts, represented by underwater plateaus, aseismic ridges and islands. They have an oceanic crust of increased thickness 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, the Canary Islands, Cape Verde, Azores, paired uplifts of Sierra and Sierra Leone, Rio Grande and the Whale Ridge, Bermuda Uplift, Cameroon group of volcanoes, etc. In the Atlantic Ocean there are intraplate uplifts of non-volcanic nature, which include the underwater Rockall plateau, separated from British Isles trog of the same name. The plateau is a microcontinent that broke away from Greenland in the Paleocene. Another microcontinent that also separated from Greenland is the Hebrides in northern Scotland. The underwater marginal plateaus off the coast of Newfoundland (Great Newfoundland, Flemish Cap) and off the coast of Portugal (Iberian) were separated from the continents as a result of rifting at the end of the Jurassic - the beginning of the Cretaceous.
The Atlantic Ocean is divided by transoceanic transform faults into segments that have 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, spreading of the ocean floor was preceded by continental rifting, traces of which are recorded in the form of half-grabens (see Graben) filled with clastic sediments on the American and North African margins of the ocean. At the end of the Jurassic - the beginning of the Cretaceous, the Antarctic segment began to open up. In the Early Cretaceous, spreading was experienced by the Southern Segment in the South Atlantic and the Newfoundland-Iberian Segment in the North Atlantic. The 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 a secondary axis, which continued until the late Eocene. The North and South Atlantic merged in the mid-Cretaceous - Eocene with the formation of the Equatorial segment.
Bottom sediments . The thickness of modern bottom sediments varies from a few meters in the crest zone of the Mid-Atlantic Ridge to 5-10 km in transverse fault zones (for example, in the Romanche Trench) and at the foot of the continental slope. In deep-sea basins their thickness ranges 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, coccolithophores). Their composition varies from coarse sands (at depths up to 200 m) to silts. At depths of more than 4500-4700 m, calcareous silts are replaced by polygenic and siliceous planktogenic sediments. The former occupy about 28.5% of the ocean floor area, lining the bottoms of basins, and are represented by red deep-sea oceanic clay (deep-sea clayey silts). These sediments contain significant amounts of manganese (0.2-5%) and iron (5-10%) and very small amounts of carbonate material and silicon (up to 10%). Siliceous plankton sediments occupy about 6.7% of the ocean floor area, of which the most common are diatomaceous oozes (formed by the skeletons of diatoms). They are common off the coast of Antarctica and on the shelf of South-West Africa. Radiolarian muds (formed by radiolarian skeletons) are found mainly in the Angola Basin. Along the ocean coasts, on the shelf and partly on the continental slopes, terrigenous sediments of various compositions (gravel-pebble, sandy, clayey, etc.) are developed. The composition and thickness of terrigenous sediments are determined by the bottom topography, the activity of the supply of solid material from land and the mechanism of their transfer. Glacial sediments carried by icebergs are distributed along the coast of Antarctica, Greenland, Newfoundland, and the Labrador Peninsula; composed of poorly sorted clastic material including boulders, mostly 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 muds) are localized in the Gulf of Mexico, the Caribbean Sea and off the northeastern coast of Brazil; their maximum depth is 3500 meters. Volcanogenic sediments are developed near the volcanic islands (Iceland, Azores, Canaries, Cape Verde, etc.) and are represented by fragments of volcanic rocks, slag, pumice, and volcanic ash. Modern chemogenic sediments are found on the Great Bahama Bank, in the Florida-Bahamas, Antilles regions (chemogenic and chemogenic-biogenic carbonates). Ferromanganese nodules are found in the North American, Brazilian, and Cape Verde basins; 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 large extent of the Atlantic Ocean, its waters are located in almost all natural climatic zones - from subarctic in the north to Antarctic in the south. From the north and south, the ocean is widely exposed to Arctic and Antarctic waters and ice. The lowest air temperatures are observed in the polar regions. Over the Greenland coast, temperatures can drop to -50°C, while temperatures of -32.3°C have been recorded in the southern Weddell Sea. In the equatorial region the air temperature is 24-29 °C. The pressure field over the ocean is characterized by a consistent change of stable large pressure formations. There are anticyclones over the ice domes of Greenland and Antarctica, in the temperate latitudes of the Northern and Southern Hemispheres (40-60°) there are cyclones, in lower latitudes there are anticyclones separated by a zone of low pressure at the equator. This pressure structure maintains stable winds in tropical and equatorial latitudes east direction(trade winds), in temperate latitudes - strong westerly winds, which navigators called the “roaring forties”. Strong winds are also typical for the Bay of Biscay. In the equatorial region, the interaction of the northern and southern pressure 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 usually move 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. Low pressure areas in temperate and equatorial latitudes often experience precipitation and heavy cloud cover. Thus, at the equator over 2000 mm of precipitation falls per year, in temperate latitudes - 1000-1500 mm. In areas of high pressure (subtropics and tropics), precipitation decreases to 500-250 mm per year, and in areas adjacent to the desert coasts of Africa and in the South Atlantic High - to 100 mm or less per year. Fogs are common in areas where warm and cold currents meet, for example in the Newfoundland Banks and La Plata Bay.
Hydrological regime. Rivers and water balance. In the Atlantic Ocean basin, 19,860 km 3 of water is carried out by rivers annually, which is more than in any other ocean (about 45% of the total flow into the World Ocean). The largest rivers (with an annual flow 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 underground 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 compensated by the influx of water, mainly from the Pacific Ocean; 3,470 thousand km 3 /year flows through the Drake Passage with the flow of the Western Winds, and only 210 thousand km 3 /year leaves from the Atlantic Ocean to the Pacific Ocean. From the Arctic Ocean, 260 thousand km 3 /year flows into the Atlantic Ocean through numerous straits, and 225 thousand km 3 /year of Atlantic water flows back to the Arctic Ocean. The water balance with the Indian Ocean is negative, in Indian Ocean With the current of the Western Winds, 4976 thousand km 3 /year is carried out, and only 1692 thousand km 3 /year comes back with the Coastal Antarctic Current, deep and bottom waters.
Temperature. The average temperature of ocean waters as a whole is 4.04 °C, and that of surface waters is 15.45 °C. The distribution of water temperature on the surface is asymmetrical 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 Northern Hemisphere, the warmest waters of the open part of the ocean (thermal equator) are located between 5 and 10 ° northern latitude, that is, shifted north of the geographic equator. Features of large-scale water circulation lead to the fact that the surface water temperature along the western shores of the ocean is approximately 5°C higher than at the eastern shores. The warmest water temperature (28-29°C) on the surface is in the Caribbean Sea and the Gulf of Mexico in August, the lowest is off the coast of Greenland, Baffin Island, the 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 to an average of 5.5 °C (1.5-2 °C in Antarctic intermediate waters). In deep waters, the water temperature is on average 2.3 °C, in near-bottom waters - 1.6 °C. At the very bottom, the water temperature increases slightly due to geothermal heat flow.
Salinity. The waters of the Atlantic Ocean contain about 1.1·10 16 tons of salts. The average salinity of the waters of the entire ocean is 34.6‰, and that of surface waters is 35.3‰. The highest salinity (over 37.5‰) is observed on the surface in subtropical areas, where the evaporation of water from the surface exceeds its supply with precipitation, the lowest (6-20‰) in the mouths of large rivers flowing into the ocean. From the subtropics to high latitudes, surface salinity 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 northern part of the 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, bottom waters, which occupy the deepest depressions of the ocean, have a salinity of 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 of greater importance in the formation of the water density field. Waters with the lowest density are located in the equatorial and tropical zones with high water temperatures and the strong influence of runoff from rivers such as the Amazon, Niger, Congo, etc. (1021.0-1022.5 kg/m3). In the southern part of the ocean, the density of surface water increases to 1025.0-1027.7 kg/m 3, in the northern part - to 1027.0-1027.8 kg/m 3. The density of the deep waters of the Atlantic Ocean is 1027.8-1027.9 kg/m3.
Ice regime. In the northern part of the Atlantic Ocean, first-year ice is formed mainly in the inland seas of temperate latitudes, while multi-year ice is carried out from the Arctic Ocean. The extent of ice cover in the northern part of the Atlantic Ocean changes significantly; in winter, pack ice can reach 50-55° north latitude in different years. There is no ice in summer. The boundary of Antarctic multi-year 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 × 10 12 tons per year enter the Atlantic Ocean from the Arctic glaciers, mainly from the Jakobshavn glacier (in the area of Disko Island off the west coast of Greenland). The average lifespan of Arctic icebergs is about 4 years, Antarctic icebergs are somewhat longer. The distribution limit 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° south latitude in the central part of the ocean and at 35° south latitude on the western and eastern periphery.
Currents. The circulation of the waters of the Atlantic Ocean is divided into 8 quasi-stationary oceanic gyres, located almost symmetrically relative to the equator. From low to high latitudes in the Northern and Southern Hemispheres there are tropical anticyclonic, tropical cyclonic, subtropical anticyclonic, and subpolar cyclonic oceanic gyres. Their boundaries, as a rule, are the main ocean currents. The warm Gulf Stream originates near the Florida Peninsula. Absorbing the warm waters of the Antilles Current and the Florida Current, the Gulf Stream heads to the northeast and in high latitudes it is divided into several branches; the most significant of them are the Irminger Current, which carries warm waters into the Davis Strait, the North Atlantic Current, the Norwegian Current, going into the Norwegian Sea and further to the northeast, along the coast of the Scandinavian Peninsula. The cold Labrador Current comes out of Davis Strait to meet 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 Denmark Strait into the ocean. In the low latitudes of the Atlantic Ocean, the warm Northern Trade Wind Currents and the Southern Trade Wind Currents flow from east to west; between them, at approximately 10° north latitude, the Inter-Trade Wind Countercurrent runs from west to east, which is active mainly in the summer in the Northern Hemisphere. Separated from the Southern Trade Wind Currents is the Brazilian Current, which runs from the equator to 40° south latitude along the coast of America. The northern branch of the Southern Trade Wind Currents forms the Guiana Current, which is directed from south to northwest until it joins the waters of the Northern Trade Wind Currents. Off the coast of Africa, from 20° north latitude to the equator, the warm Guinea Current passes, and in the summer the Intertrade Countercurrent is connected to it. In the southern part of the Atlantic Ocean, the cold Western Wind Current (Antarctic Circumpolar Current) crosses, which enters the Atlantic Ocean through the Drake Passage, descends to 40° south latitude and exits into the Indian Ocean south of Africa. Separated from it are the Falkland Current, which reaches 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. Cold Canary Current runs from north to south - from the shores of the Iberian Peninsula to the Cape Verde Islands, where it turns into the Northern Trade Wind Currents.
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 density increases as a result of mixing 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 the 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 ranges from negative (in high southern latitudes) to 2.5 ° C, and 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, and the 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 up in the North Pacific Ocean.
Tides and swells. 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 (the northern part of the 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. Quite rarely (once every 15-20 years) waves with a height of 22-26 m have been observed.
Flora and fauna. The large extent 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, the ocean is home to about 200 thousand species of plants and animals (of which about 15,000 species are fish, about 600 species of cephalopods, about 100 species of whales and pinnipeds). Life is distributed very unevenly in the ocean. There are three main types of zonality in the distribution of life in the ocean: latitudinal, or climatic, vertical and circumcontinental zonation. 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 to high latitudes.
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/m3). During the year, biomass can change 10-100 times. The main types of phytoplankton are diatoms, zooplankton - copepods and euphausids (up to 90%), as well as chaetognaths, hydromedusae, ctenophores (in the north) and salps (in the south). At low latitudes, 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 Gulf of Mexico and Guinea. Phytoplankton is represented mainly by coccolithines and peridineans; the latter can develop in huge quantities in coastal waters, causing the catastrophic phenomenon of “red tide”. Zooplankton at low latitudes is represented by copepods, chaetognaths, hyperids, hydromedusae, siphonophores and other species. There are no clearly defined 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 places where there are suitable conditions - soils suitable for attachment to the bottom, the absence or moderate speeds of bottom currents, etc. In the high latitudes of the Atlantic Ocean, the main part of phytobenthos consists of kelp and red algae. In the temperate zone of the North Atlantic Ocean, along the American and European coasts, there are brown algae (fucus and ascophyllum), kelp, desmarestia and red algae (furcellaria, ahnfeltia, etc.). Zostera is common on soft soils. In the temperate and cold zones of the South Atlantic Ocean, brown algae predominate. 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 three species of Sargassum algae) form accumulations on the surface in the form of ribbons from 100 m to several kilometers long.
Most of the nekton biomass (actively swimming animals - fish, cephalopods and mammals) consists of fish. The largest number of species (75%) live in the shelf zone; with depth and distance from the coast, the number of species decreases. Characteristic for cold and temperate zones: 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, pilot whales, bottlenose whales, etc.).
There is great similarity between the faunas of temperate and high latitudes of both hemispheres. At least 100 species of animals are bipolar, that is, they are characteristic of both temperate and high zones. The tropical zone of the Atlantic Ocean is characterized by: fish - various sharks, flying fish, sailfish, various types of tuna and luminous anchovies; among animals - sea turtles, sperm whales, river dolphin; Cephalopods are also numerous - various types of squid, octopuses, etc.
The deep-sea fauna (zoobenthos) of the Atlantic Ocean is represented by sponges, corals, echinoderms, crustaceans, mollusks, and various worms.
History of the study
There are three stages of exploration of the Atlantic Ocean. The first is characterized by the establishment of the boundaries of the ocean and the discoveries of its individual objects. In the 12th-5th centuries BC, the Phoenicians, Carthaginians, Greeks and Romans left descriptions of sea travels and the first sea maps. 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 tidal phenomena in the Atlantic Ocean. Mentions of the Canary Islands date back to the 1st century AD. In the 9th and 10th centuries, the Normans (Eirik Raudi and his son Leif Eirikson) crossed the ocean, visited Iceland, Greenland, Newfoundland and explored the shores of North America to 40° north latitude. In the era of the Great geographical discoveries(mid-15th - mid-17th centuries) sailors (mainly Portuguese and Spaniards) explored the route to India and China along the coast of Africa. The most outstanding voyages during this period were carried out by the Portuguese B. Dias (1487), the Genoese H. Columbus (1492-1504), the Englishman J. Cabot (1497) and the Portuguese Vasco da Gama (1498), who for the first time tried 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 through the strait, later named after him. In the 16th and 17th 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 ocean map). The Falkland Islands were discovered in 1591-92. The southern shores of the Atlantic Ocean (continent 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 ocean's boundaries.
The second stage is characterized by the study of the physical properties of ocean waters, temperature, salinity, currents, etc. In 1749, the Englishman G. Ellis made the first measurements of temperature at various depths, repeated by the Englishman J. Cook (1772), the Swiss O. Saussure (1780), Russian I.F. Krusenstern (1803), etc. In the 19th century, the Atlantic Ocean became a testing ground for developing new methods for exploring depths, new technology and new approaches to organizing work. For the first time, bathometers, deep-sea thermometers, thermal depth gauges, deep-sea trawls and dredges were used. Among the most significant are 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 leadership of J. Ross (1840-43); American - on the "Cyclub" and "Arctic" under the leadership of M. F. Mori (1856-57). Real comprehensive oceanographic research of the ocean began with an expedition on the English corvette Challenger, led by C.W. Thomson (1872-76). The significant expeditions that followed were carried out on the ships Gazelle (1874-76), Vityaz (1886-89), Valdivia (1898-1899), and 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 led expeditionary research on the yachts “Irendel”, “Princess Alice”, “Irendel II”, “Princess Alice II” in the northern part of the ocean. During these same years, he organized the Oceanographic Museum in Monaco. Since 1903, work began on “standard” sections in the North Atlantic under the leadership of the International Council for the Exploration of the Sea (ICES), the first international oceanographic scientific organization that 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, and Atlantis. In 1931, the International Council of Scientific Unions (ICSU) was formed, which is still active today, organizing and coordinating ocean research.
After World War II, echo sounders began to be widely used to study the ocean floor. This made it possible to obtain a real picture of the topography of the ocean floor. In the 1950-70s, comprehensive geophysical and geological studies of the Atlantic Ocean were carried out and the features of the topography of its bottom, tectonics, and the structure of the sedimentary strata were established. Many large forms of bottom relief have been identified (underwater ridges, mountains, trenches, fault zones, extensive basins and uplifts), and geomorphological and tectonic maps have been compiled.
The third stage of ocean research is aimed mainly at studying its role in global processes of matter and energy transfer and its influence on climate formation. The complexity and wide range of research efforts required extensive international collaboration. The Scientific Committee for International Research plays an important role in the coordination and organization of international research. oceanographic research(SCOR), formed in 1957, the Intergovernmental Oceanographic Commission of UNESCO (IOC), active since 1960, and other international organizations. In 1957-58, major work was carried out within the framework of the first International Geophysical Year (IGY). Subsequently, large international projects were aimed not only at studying individual parts of the Atlantic Ocean (for example, EQUALANT I-III; 1962-1964; Polygon, 1970; SICAR, 1970-75; POLIMODE, 1977; TOGA, 1985-89), but also at study of it as part of the World Ocean (GEOSECS, 1973-74; WOCE, 1990-96, etc.). During the implementation of these projects, the peculiarities of water circulation 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 Soviet Mir deep-sea submersibles explored the unique ecosystems of geothermal regions of the ocean rift zone. If in the early 1980s there were about 20 international ocean research projects, then by the 21st century there were over 100. The largest programs: “International Geosphere-Biosphere Program” (since 1986, 77 countries participate), it includes projects “Interaction land - ocean in the coastal zone" (LOICZ), "Global flows of matter in the ocean" (JGOFS), "Dynamics of global ocean 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 global economy among other oceans on our planet. Human use of the Atlantic Ocean, as well as other seas and oceans, occurs in several main areas: transport and communications, fishing, extraction of mineral resources, energy, and 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 turnover; at the end of the 20th century, up to 3.5 billion tons of cargo were transported through its waters per year (according to IOC). About 1/2 of the transport volume is oil, gas and petroleum products, followed by general cargo, then iron ore, grain, coal, bauxite and alumina. The main direction of transportation is the North Atlantic, which passes 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). Adjacent to this direction are the Norwegian, Northern and inland seas Europe (Baltic, Mediterranean and Black). Mainly raw materials (coal, ores, cotton, timber, etc.) and general cargo are transported. Other important transportation directions are the South Atlantic: Europe - Central (Panama, etc.) and South America (Rio de Janeiro, Buenos Aires); East Atlantic: Europe - southern Africa (Cape Town); Western Atlantic: North America, South America - southern Africa. Before the reconstruction of the Suez Canal (1981), most oil tankers from the Indian basin were forced to go around Africa.
Passenger transportation has occupied 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 ship, the 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 could cross the ocean the fastest. This prize was awarded, for example, to such famous liners as the Lusitania (4 days and 11 hours), the Normandy (4 days and 3 hours), and the Queen Mary (4 days without 3 minutes). The last time the Blue Ribbon was awarded was 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 airliner 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 per year; in 1958, the volume of passenger transportation by air was equal to sea transportation, and then an increasing proportion of passengers preferred air transport (record flight time for a supersonic airliner Concorde route New York - London - 2 hours 54 minutes). The first non-stop flight across the Atlantic Ocean was made on June 14-15, 1919 by English pilots J. Alcock and A. W. Brown (Newfoundland - Island of Ireland), the first non-stop flight across the Atlantic Ocean alone (from continent to continent) on May 20-21, 1927 - American pilot C. Lindbergh (New York - Paris). At the beginning of the 21st century, virtually all passenger traffic 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 continents; by the mid-1990s, there were over 10 telephone lines 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 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%) consists of herring fish (herring, sardines, etc.), cod (cod, haddock, hake, whiting, pollock, navaga, etc.), flounder, halibut, and sea bass. Production of mollusks (oysters, mussels, squid, etc.) and crustaceans (lobsters, crabs) is about 8%. FAO estimates that the annual catch of fishery products in the Atlantic Ocean is 85-90 million tons, but for most fishing areas in the Atlantic, fish catches reached their maximum in the mid-1990s and an 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 northwestern region ocean, on the Newfoundland banks, cod, herring, flounder, squid, etc. have been caught for many centuries. In the central part of the Atlantic Ocean, sardines, horse mackerel, mackerel, tuna, etc. are being fished. In the south, on the Patagonian-Falkland shelf, which is elongated in latitude, both warm-water species (tuna, marlin, swordfish, sardines, etc.) and cold-water species (blue whiting, hake, notothenia, toothfish, etc.). Off the coast of western and southwestern Africa, sardines, anchovies and hake are caught. In the Antarctic region of the ocean, planktonic crustaceans (krill), marine mammals, fish - notothenia, toothfish, silverfish, etc. are of commercial importance. Until the mid-20th century, active fishing was carried out in the high-latitude northern and southern regions of the ocean various types pinnipeds and cetaceans, but in recent decades it has sharply declined due to the depletion of biological resources and due to environmental measures, including intergovernmental agreements to limit their production.
Mineral resources. The mineral wealth of the ocean floor is being increasingly exploited. Oil and combustible gas deposits have been studied more fully; the first mention of their exploitation in the Atlantic Ocean dates back to 1917, when oil production on an industrial scale began in the eastern part of the Maracaibo lagoon (Venezuela). The largest offshore production centers: Gulf of Venezuela, Maracaibo Lagoon (Maracaiba oil and gas basin), Gulf of Mexico (Gulf of Mexico oil and gas basin), Gulf of Paria (Orinoc oil and gas basin), Brazilian shelf (Sergipe-Alagoas oil and gas basin), Gulf of Guinea (Gulf of Guinea oil and gas basin) ), North Sea ( North Sea oil and gas bearing region), etc. Placer deposits of heavy minerals are common along many coasts. The largest developments of placer deposits of ilmenite, monocyte, zircon, and rutile are carried out off the coast of Florida. Similar deposits are located in the Gulf of Mexico, off the east coast of the United States, as well as Brazil, Uruguay, Argentina and the Falkland Islands. On the shelf of southwest Africa, coastal marine diamond deposits are being mined. Gold placers were discovered 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. Coal deposits are being developed in the coastal waters of Great Britain and Canada, extracting it 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 and gravel are mined for construction and glass production. 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. Large fields of ferromanganese nodules were found at the bottom of the North American Basin and on the Blake Plateau; their total reserves in the Atlantic Ocean are estimated at 45 billion tons.
Recreational resources. Since the 2nd half of the 20th century, the use of ocean recreational resources has been of great importance for the economies of coastal countries. Old resorts are being developed and new ones are being built. Since the 1970s, ocean liners have been laid down, intended only for cruises; they are distinguished by their large size (displacement of 70 thousand tons or more), increased level of comfort and relative slowness. The main routes of cruise ships are the Atlantic Ocean - the Mediterranean and Caribbean Seas and the Gulf of Mexico. Since the late 20th and 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 generated by the Atlantic Ocean's tides is estimated at approximately 250 million kW. In the Middle Ages, mills and sawmills were built in England and France using tidal waves. There is a tidal power station at the mouth of the Rance River (France). The use of ocean hydrothermal energy (temperature differences in surface and deep waters) is also considered promising; a hydrothermal station operates on the coast of Côte 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; V South America- Maracaibo, Rio de Janeiro, Santos, Buenos Aires; in Africa - Dakar, Abi-jan, Cape Town. Russian port cities do not have direct access to the Atlantic Ocean and are located on the shores of 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 20th century. M., 1978; Terms. Concepts, reference tables / Edited by S. G. Gorshkov. M., 1980; Atlantic Ocean. L., 1984; Biological resources of the Atlantic Ocean / Responsible. editor D. E. Gershanovich. M., 1986; Broeker W. S. The great ocean conveyor // Oceanography. 1991. Vol. 4. No. 2; Pushcharovsky Yu. M. Tectonics of the Atlantic with elements of nonlinear geodynamics. M., 1994; World ocean atlas 2001: In 6 vol. Silver Spring, 2002.
P. N. Makkaveev; A. F. Limonov (geological structure).
Secrets of the Atlantic Ocean
The Atlantic Ocean is famous human civilization from time immemorial. It was here, according to ancient legends, that the mysterious island of Atlantis was located, which sank under the water seventeen thousand years ago. A warlike and courageous people (the Atlanteans) lived on it, and the god Poseidon reigned over it along with his wife Cleito. Their eldest son's name was Atlan. In his honor, the boundless sea washing this land was named Atlantic.
Atlantic Ocean
The mysterious civilization sank into oblivion, the sea was renamed the ocean, but the name remained the same. The secrets of the Atlantic Ocean have not disappeared anywhere. Over the centuries, there have been no fewer of them. But before you get acquainted with everything unusual and mysterious, you need to get a general idea of the majestic waters that simultaneously wash the shores of hot Africa, the lands of old Europe, and the distant rocky coast of the American continent, covered in the haze of fairy tales.
Nowadays, the Atlantic Ocean is the name given to a huge body of water on planet Earth, which accounts for 25% of the volume of the World Ocean. Its area is almost 92 million km², together with the adjacent seas and the Atlantic part of the Southern Ocean. From north to south, the waters of the Atlantic stretch for 15.5 thousand km, and from west to east, in the narrowest part (from Brazil to Liberia), they have a width of 2.8 thousand km.
If we take the distance of the Atlantic waters from the western coast of the Gulf of Mexico to the eastern coast of the Black Sea, then there will be a completely different figure - 13.5 thousand km. The depth of the ocean is also a big difference. Her average value is 3600 m, and the maximum was recorded in the Puerto Rico trench and corresponds to 8742 meters.
The floor of the Atlantic is divided lengthwise into two parts by the Mid-Atlantic Ridge. It exactly follows the contours of a huge reservoir and stretches in a wide, winding mountainous chain: from the north - from the Reykjanes Ridge (Iceland), to the African-Antarctic Ridge in the south (Bouvet Island), going beyond the distribution of Arctic ice.
To the right and left of the ridge there are scattered basins, trenches, faults, and small ridges that make the topography of the ocean floor very complex and confusing. The coastline (especially in northern latitudes) also has a complex structure. It is heavily indented by small bays and has vast water areas that extend deep into the land and form seas. An integral part are the numerous straits in the coastal zone of the continents, as well as straits and channels connecting the Atlantic with the Pacific Ocean.
The Atlantic Ocean washes the shores 96 state entities. Its property includes 14 seas and 4 large bays. The richly diverse climate in these geographical and geological parts of the earth's surface is provided by numerous surface currents. They flow freely in all directions and are divided into warm and cold.
In the northern latitudes, up to the equator, the Northern Trade Wind, Gulf Stream and Northern Atlantic current. They carry warm waters and delight the surrounding world with a mild climate and high temperatures. This cannot be said about the Labrador and Canary currents. The latter are classified as cold and create frosty and slushy weather in the adjacent lands.
South of the equator the picture is the same. The warm South Trade Wind, Guinea and Brazilian Currents rule here. The cold Western Winds and the Bengal Winds try to be in no way inferior to their more humane colleagues and also make their feasible negative contribution to the formation of the climate southern hemisphere. In general, the average temperature on the surface of the Atlantic Ocean is plus 16° Celsius. At the equator it can reach up to 28° Celsius. But in the northern latitudes it is very cold - here the water freezes.
Icebergs of the Atlantic
From what has been said, it is not difficult to guess that the waters of the Atlantic are squeezed from the north and south by eternal giant ice crusts. True, regarding eternity, it’s a little overkill, since very large blocks of ice often break off from them and begin to slowly drift towards the equator. These blocks are called icebergs, and they move north of Greenland up to 40° N. sh, and in the south from Antarctica to 40° S. w. Their remains are also observed closer to the equator, reaching 31-35° southern and northern latitudes.
Very large sizes are a loose concept. More specifically, there are icebergs whose length is tens of kilometers, and whose area sometimes exceeds 1000 km². These ice floes can travel across the ocean for years, hiding their true size under the water surface.
The fact is that a mountain of ice shines blue above the water, which corresponds to only 10% of the total volume of the iceberg. The remaining 90% of this block is hidden in the ocean depths due to the fact that the density of ice does not exceed 940 kg/m³, and the density of sea water on the surface ranges from 1000 to 1028 kg/m³. The usual, average height of an iceberg, as a rule, corresponds to 28-30 meters, while its underwater part is slightly more than 100-120 meters.
Meeting such a sea traveler was never a joy for ships. It poses the greatest danger already in adulthood. By this time, the iceberg has melted significantly, its center of gravity has shifted, and the huge ice block turns over. Its underwater part is above the water. It does not shine blue, but is a dark blue ice cap, which, especially in poor visibility conditions, is very difficult to distinguish on the surface of the ocean.
The sinking of the Titanic
A typical example of the treachery of floating ice blocks is the sinking of the Titanic, which occurred on the night of April 14-15, 1912. It sank 2 hours 40 minutes after colliding with an iceberg in the northern waters of the Atlantic Ocean (41° 43′ 55″ N, 49° 56′ 45″ E). This resulted in the death of 1,496 passengers and crew members.
True, we must immediately make a reservation: attributing everything to a “lost” iceberg is rather imprudent. This shipwreck is still one of the greatest mysteries of the Atlantic Ocean today. There is still no clue to the reasons for the tragedy, although there are a great many different theories and assumptions.
It is assumed that the largest passenger ship in the world (length 269 m, width 28.2 m, displacement 46,300 tons) collided with an iceberg, which was of venerable age and had apparently capsized more than once in the water. Its dark surface did not give any reflections; it merged with the water surface of the ocean, so it was very difficult to notice the huge floating ice block in a timely manner. The culprit of the tragedy was recognized only when he was 450 meters from the ship, and not 4-6 km away, as usually happens in such situations.
The sinking of the Titanic caused a lot of noise. It was a world sensation at the beginning of the second decade of the twentieth century. The main thing that amazed everyone was how such a huge and reliable ship could sink so quickly, dragging hundreds and hundreds of unfortunate people with it to the bottom. Nowadays, many researchers tend to see the true causes of the terrible tragedy not in the ill-fated iceberg (although few deny its indirect role), but in completely other factors, which for some reason, at one time, were hidden from the general public.
Versions, guesses, assumptions
The official conclusion of the commission investigating the disaster was unequivocal - the ice of the Atlantic turned out to be stronger than steel. He ripped open the underwater hull of the Titanic like a tin can. The wound was terrible: its length reached 100 meters, and out of sixteen waterproof compartments, six were damaged. This turned out to be enough for the proud Briton to sink to the bottom and become silent forever at enormous depths, taking with him human lives and colossal material values to the sea soil.
The sinking of the Titanic
The sinking of the Titanic
Such a verdict is not convincing for a specialist, and even a person far from shipbuilding understands that the supporting hull of a huge liner plowing the oceans cannot in any way resemble a tin can. The melted ice of the old iceberg also does not have sufficient hardness, which, judging by the conclusion, should have exceeded the strength of a diamond, in order to pierce the steel plating of a multi-ton passenger ship for tens of meters.
You can build various assumptions and hypotheses for as long as you like, but only practical research can give answers to all questions. In this situation, given the depth at which the Titanic lay, exploration work became possible no earlier than the 80s of the 20th century. It was by this time that deep-sea vehicles capable of for a long time located at a depth of 4 kilometers.
The first such swallow was the expedition of the American oceanographer Robert Ballard, which arrived at the site of the tragedy on the ship Knor in September 1985. It was armed with the Argo deep-sea towed complex. It was he who determined the depth of the remains of the Titanic. The water thickness in this place was 3,750 meters. The ship was lying on seabed, split into two parts, the distance between them was approximately 600 meters.
No visible damage was found that caused the death of the ocean liner. Robert Ballard believed that they were hidden by the soil in which the multi-ton structure was stuck. The laceration on the Titanic’s hull was not found during the second expedition organized by the American scientist in 1986.
French and American specialists followed the beaten path. In the summer of 1987, they arrived in the waters of the Atlantic Ocean and spent two long months at the disaster site. Using the deep-sea submersible Nautilus, researchers recovered more than 900 objects from the bottom that were on board the sunken ship. These were samples of ship utensils, some of which ended up in museums, and some were distributed to private collections.
Survey of the Titanic
Submersible explores the sunken Titanic
Finally, in 1991, the ship Akademik Mstislav Keldysh arrived at the site of the sinking of the Titanic. On board was an international research expedition led by Canadian geologist-oceanographer Steve Blask. The expedition had at its disposal two autonomous underwater vehicles, Mir-1 and Mir-2. The researchers made 38 dives on them. The ship's hull was examined, a sample of the side plating was taken, film, video and photography were taken.
Despite all efforts, a ragged hole several tens of meters long was not found. But we managed to find a hole, the size of which did not exceed a square meter, and numerous cracks were noticed along the lines of the rivets.
A steel fragment that broke off from the Titanic's hull was sent for testing. It was tested for metal fragility - the conclusion was not reassuring: the prototype was strikingly fragile. This could be attributed to the long 80 years on the seabed, which significantly affected the properties of the steel. Therefore, for the objectivity of the picture, a similar piece of metal, preserved at the shipyard since 1911, was tested. The result was almost the same.
It's hard to believe, but the Titanic's hull did not respond regulatory requirements. It was made from material with high content sulfur compounds. The latter gave the steel structure high fragility, which, in combination with ice water, made it very fragile.
If the hull were made of steel that met all standards and requirements, then after contact with an iceberg, it would bend, but retain its integrity. In this situation, the ship hit an iceberg on its starboard side - and the impact was of little force, but the fragile hull of the Titanic could not withstand it either. It split along the rivet lines below the waterline. Ice water poured into the resulting holes, which instantly filled the lower compartments and, most likely, caused the explosion of the hot steam boilers.
The huge ship began to rapidly plunge into the waters of the Atlantic. According to eyewitnesses, at first the Titanic sank on an even keel, which indicates that the lower compartments filled with water evenly. Then the bow trim appeared. The stern began to rise upward, reached a vertical position, and the multi-ton colossus very quickly sank to the bottom. Already at great depths, due to high pressure, the Titanic split into two parts, which were pulled along the ocean floor for more than 500 meters.
Who benefited from the sinking of the Titanic?
It turns out that this disaster has nothing to do with the mysteries of the Atlantic Ocean: everything seems to be clear. No, there is no need to rush to conclusions. As already mentioned, there are many versions of the death of the ocean liner, and among them there is not one that can be called the ultimate truth. There are many other assumptions, opinions of very authoritative people who consider the cause of the terrible catastrophe from a completely different angle.
So to this day there is a version that the culprit of the accident was the White Star Line company itself, the owner of the ship. It was its leaders who initially planned the construction of the Titanic with gross violations of all possible norms and rules. The purpose of this grandiose fraud was to obtain huge insurance that could improve the company's precarious financial position and save it from complete collapse.
That is why the ocean liner, despite warnings about icebergs from ships in the same area, was traveling at the maximum possible speed (20.5 miles per hour). The captain of the ship had one task - to provoke a collision of the Titanic with a huge floating ice floe.
Most likely, no one could even imagine such a number of dead people, since according to all calculations it turned out that the ship would sink for a long time. The main focus was on rescue ships, which had to have enough time to get to the scene of the tragedy and have time to save all the passengers and valuables on board. However, unpredictable fate made its own adjustments to the original scenario.
In addition to this rather dubious and unsteady version, there is another. This is a fire in a coal bunker. During long-term storage, the lower layers of coal begin to smolder, releasing explosive gas. The temperature gradually increases, and the concentration of gas vapor increases. In such a situation, an explosion can occur from a normal shock. The collision with the iceberg was the detonator that caused a huge surge of energy that tore apart and destroyed the entire lower part of the ship.
In a word, even today there is no consensus on the causes of the terrible tragedy. Only the remains of a ship resting at great depths can reveal this secret of the Atlantic Ocean. Their scrupulous study by dozens of specialists is possible only under normal earthly conditions. To do this, you need to raise the Titanic from the bottom of a huge reservoir.
Technically this is extremely difficult to achieve. As for the financial side of the issue, the picture is different. Although such work will cost crazy amounts of money, it will more than pay off. After all, we must not forget that there are gold bars worth 10 million pounds sterling on the ship. Jewelry, diamonds, jewelry are also stored here richest people of the world who sailed on this ship. Fragments of the Titanic's hull, the remains of the interior, and dishes will go out of auction with a bang at incredible prices.
If we consider the unfortunate Titanic as a source of material wealth, then he is by no means alone. The bottom of the Atlantic Ocean is the Klondike, Eldorado. Here lies a huge number of ships that are simply filled with precious metals, diamonds, and other valuables that can make anyone rich who gets to them. This is precisely the whole question: breaking through the thickness of ocean waters is an impossible task not only for individual adventurers, but also for serious companies and reputable financial structures.
Underwater ship graveyards
At the beginning of the 21st century, there are many companies specializing in the search for sunken ships. The game is worth the candle, since according to experts, at least 80,000 ships from all countries and peoples that have been shipwrecked over the past 400 years rest on the bottom of the Atlantic alone, with valuables worth $600 billion on board.
One of these companies, the American company Odyssey, discovered a Spanish sailing ship in the Canary Islands in 2007. On board there were 500 thousand ancient gold and silver coins. Their total weight reached 17 tons, and the cost was 500 million dollars. This is 100 million dollars more than the wealth that was recovered in 1985 from a Spanish galleon that sank off the coast of Florida in the twenties of the 17th century.
The lion's share of all the valuables that sank to the bottom of the ocean in the 16th and first half of the 17th centuries rested precisely on Spanish ships, which in a continuous caravan carried gold, silver, precious stones and products made from them to Europe from America from the Indian peoples.
In theory, goods obtained in this way cannot be the property of the state. The Spanish government thought differently. At the beginning of the 21st century, it declared 800 Spanish ships that sank in the 16th-18th centuries, carrying illegally acquired utensils, a national treasure. The monetary equivalent of all this wealth is estimated at 130 billion dollars.
Underwater treasures are available to search teams in the coastal areas of the Atlantic Ocean. Here, as a rule, ships sank after hitting shoals or reefs. In the vast expanses of water, where at least 3000 meters lie under the keel, galleons, brigantines, frigates carrying cargo, and then steamships, motor ships, yachts, battleships sank to the bottom, experiencing all the power and force of ocean storms (the height of the waves in the Atlantic often reaches 10-15 meters) or deceit and cruelty pirate ships And submarines enemy during the years of hostilities.
The ratio of ships that have sunk in coastal areas and in the open ocean over the past 400 years is 85 to 15. That is, it turns out that the closer to the shore, the more dangerous. Only every seventh ship perished in the vast and majestic expanses of the Atlantic Ocean, the rest of the floating craft sank in the sight of native or foreign shores, which, as they say, were just a stone's throw away.
One of the largest underwater cemeteries is the English Channel. Its length is 560 km, its width in the west is 240 km, in the east 32 km, and the average depth is 63 m. Only in some places the depth exceeds this mark and reaches 170 m. There are many shallows and fogs are frequent. Countless ships rest at the bottom of the strait, especially in its western part.
The waters around Cape Hatteras (North Carolina, USA) are not far behind in the number of shipwrecks. Here there is a long narrow spit, the eastern ledge of which is actually the ill-fated cape. This place is characterized by countless shoals, constant storms, fogs, and strong currents. Vessels that dare to approach these shores expose themselves to complete real danger- manifestation of carelessness, frivolity and ignoring the directions almost always leads to tragic consequences.
Bermuda Triangle
Perhaps the most intriguing secret of the Atlantic Ocean can be called the Bermuda Triangle. Its peaks lie on the southern tip of Florida, Bermuda and Puerto Rico. It is part of the so-called Devil's Belt, of which the Devil's Triangle, located in the Pacific waters around Miyake Island (Japan), is also a part.
The excitement around this seemingly unremarkable place arose in the second half of the 20th century. Previously, for hundreds of years, everything seemed to be normal. The ships decorously crossed this expanse of ocean, and the crews on them had no idea what mortal danger they exposed themselves.
The year 1950 put an end to such outrageous frivolity. It was then that a short article by Associated Press correspondent Edward Johnson was published. It was not even an article, but a thin brochure published in Florida in a small edition. Its name was “Bermuda Triangle”, and the facts presented in it told about the mysterious disappearances of ships and planes in the Bermuda area.
Bermuda Triangle
It did not attract the attention of the public in any way, but apparently forced the attention of certain people who feed on sensations and bestsellers. However, it took almost 15 years before Vincent Gladdis’s article entitled “The Deadly Bermuda Triangle” saw the light of day. It was published in 1964 in a spiritualist magazine. With a short break, a book by the same author, “Invisible Horizons,” was published. In it, a whole chapter was already devoted to the mysterious section of the ocean.
A more detailed, solid and capacious work was presented to readers ten years later. The author of this bestseller, simply and succinctly called “The Bermuda Triangle,” was Charles Berlitz. It provided a lot of data about the mysterious disappearances of ships and aircraft, and also described incomprehensible phenomena associated with changes in the properties of time and space. Reputable publishers different countries reprinted this book, and in a short time, tens of millions of citizens living in different parts of the planet learned about the Bermuda Triangle.
In any business, there will always be corrosive skeptics, whom don’t feed with bread, but let the fly in the ointment spoil the barrel of honey. A blow to such a successfully and dynamically spreading sensation was dealt already in the next 1975 by the American journalist Lawrence David Kusche. This gentleman left no stone unturned from all the arguments and statements of Charles Berlitz on the pages of his book “The Mystery of the Bermuda Triangle Solved.”
To the credit of the author, the content of the book is by no means unsubstantiated criticism, which would be based on envy of a more successful and cunning colleague, but a serious study based on a painstaking study of documents and eyewitness accounts. It was on the basis of factual material that many errors, inaccuracies, and sometimes outright hoaxes in the work of Charles Berlitz were identified.
The conclusion of Lawrence David Kushe's book is clear: nothing mysterious, supernatural, or inexplicable is happening in the Bermuda Triangle. The statistics of tragedies in this section of the Atlantic Ocean correspond to similar data in any other place of the huge body of water. Mysterious disappearances of material objects are fictitious, and stories about ships abandoned by crews, about lost time, about instantaneous movement in space for hundreds of kilometers are a myth.
Critics of anomalous phenomena are sober-minded people. In order to convince them of something, you need to provide ironclad evidence of this phenomenon. But in Everyday life It is not that simple. What lies beyond the real cannot be explained from the point of view of the laws of physics, mechanics or chemistry. Rather, human imagination and belief in the mysterious and unusual dominate here.
By the way, many paranormal phenomena occurring in the Bermuda Triangle can be interpreted as a direct consequence of ordinary banal processes occurring in the waters of the Atlantic. Eg, mysterious disappearance sea vessels has a simple explanation related to methane emissions. This gas escapes from gas hydrate deposits on the seabed and saturates the water. The density of the latter drops sharply. A ship caught in such a section of the ocean instantly sinks.
The methane released is not limited to aquatic environment. It rises into the air and also reduces its density. This can lead to the loss of aircraft, which is almost impossible to explain to people on the ground. We must not forget that the gas dissipates very quickly in both water and air. That is, he is a killer who leaves no traces behind.
Anomalies over time can be explained increased activity magnetic field in the Bermuda Triangle area. Airplane passengers caught in a cluster of magnetic forces can verify their influence by looking at the hands of their watches that have stopped or slowed down. After some time negative factor disappears, the clock starts running normally again, but everyone, without exception, is behind by the same number of minutes. This gives rise to the false belief that the plane disappeared into another dimension.
If we talk about ships found in the ocean that did not have a single crew member, then the blame can be laid on infrasound, which occurs on the water surface under certain conditions. The human brain, heart, and other organs of his body - they all have their own vibration frequency. If some of them coincide with the frequency of infrasound, then the resulting resonance can mercilessly hit people’s psyches, plunge them into horror and panic, force them to jump overboard and die in the water.
All the arguments presented look quite convincing and realistic. But we must not forget that this is not evidence, but only speculation. Supporters of the paranormal version can also present to the public their vision of the problem, which will be no less convincing and will find many adherents.
Where is the truth? Probably, as always, in the middle. A sober look, combined with faith in the unusual and supernatural, will be more productive in solving the mysteries of not only the Bermuda Triangle, but also other mysteries of the Atlantic Ocean, of which there are a great many both on its surface and in the dark depths.
Based on factruz material
Atlantic Ocean- the second largest ocean after the Pacific Ocean. It contains 25% of all the planet's water. The average depth is 3,600 m. The maximum is in the Puerto Rico trench - 8,742 m. The ocean area is 91 million square meters. km.
general information
The ocean arose as a result of the splitting of a supercontinent. Pangea"into two large parts, which subsequently formed into modern continents.
The Atlantic Ocean has been known to man since ancient times. Mentioning the ocean, which " called Atlantic“, can be found in records of the 3rd century. BC. The name probably arose from the legendary missing continent " Atlantis«.
True, it is not clear what territory it designated, because in ancient times people had limited means of transportation by sea.
Relief and islands
A distinctive feature of the Atlantic Ocean is the very small number of islands, as well as the complex bottom topography, which forms many pits and gutters. The deepest among them are the Puerto Rico and South Sandwich trench, whose depth exceeds 8 km.
Earthquakes and volcanoes have a great impact on the structure of the bottom; the greatest activity tectonic processes observed in the equatorial zone.
Volcanic activity in the ocean has been going on for 90 million years. The height of many underwater volcanoes exceeds 5 km. The largest and most famous are located in the Puerto Rico and South Sandwich trenches, as well as on the Mid-Atlantic Ridge.
Climate
The large meridional extent of the ocean from north to south explains the diversity of climatic conditions on the ocean surface. In the equatorial zone there are slight temperature fluctuations throughout the year and an average of +27 degrees. The exchange of water with the Arctic Ocean also has a huge impact on ocean temperature. Tens of thousands of icebergs drift from the north into the Atlantic Ocean, reaching almost tropical waters.
The Gulf Stream, the largest current on the planet, originates off the southeastern coast of North America. Water consumption per day is 82 million cubic meters, which is 60 times higher than the consumption of all rivers. The width of the current reaches 75 km. wide and depth 700 m. Current speed ranges from 6-30 km/h. The Gulf Stream carries warm waters, the temperature of the upper layer of the current is 26 degrees.
In the area of The Newfoundland Gulf Stream meets the "cold wall" of the Labrador Current. Mixing water creates ideal conditions for the proliferation of microorganisms in upper layers. Best known in this regard Large Newfoundland barrel, which is a source of fish such as cod, herring and salmon.
Flora and fauna
The Atlantic Ocean is characterized by an abundance of biomass with a relatively poor species composition in the northern and southern margins. The greatest species diversity is observed in the equatorial zone.
Of the fish, the most common families are nanothenia and white-blooded pike. Large mammals are most widely represented: cetaceans, seals, fur seals, etc. The amount of plankton is insignificant, which causes migration of whales to feeding fields to the north or to temperate latitudes, where there is more of it.
Many places in the Atlantic Ocean have been and continue to be intensive fishing grounds. Previous development of the ocean led to the fact that hunting for mammals has been widespread here for a long time. This has reduced the numbers of some animal species compared to the Pacific and Indian Oceans. 
Plants include a wide range of green, brown and red algae. The famous Sargasso forms the Sargasso Sea, popular in books and interesting stories.
Vertically, but under different conditions that determine the intensity of metabolic processes: depending on geographic latitude, amount of oxygen, transparency, etc. Depending on geographic latitude and depth, the number of plants and animals changes. In low latitudes, 1 liter of water contains more than 10 thousand microorganisms, at a depth of 1 km - 90, and at a depth of 5 km - only 15.
At a depth of about 4 meters off the coast of Cuba, a “sea fan” coral lives, which has the appearance of burdock-shaped leaves penetrated by a network of vessels - this is the soft coral Gongonaria, forming entire thickets - “underwater forests”.
In tropical waters there are many inhabitants dangerous to humans: sharks, barracudas, moray eels. There are urchin fish and invertebrate sea urchins, the pricks of which are very painful.
The deep-sea regions of the Atlantic Ocean, like other oceans, represent a special environment of huge, low temperatures and eternal darkness. Here you can find crustaceans, echinoderms, annelids, silicon sponges, and sea lilies.
In the Atlantic Ocean there is also an “ocean desert” (“ocean Sahara”) - this is the Sargasso Sea, where the biomass value is no more than 25 mg/m 3, which is primarily due, apparently, to the special gas regime of the sea.
Biological resources of the Atlantic Ocean
The Atlantic Ocean has fairly rich biological resources. It accounts for 40% of fish and seafood catches. These are fish, crustaceans, etc.
The largest catches are in the northeastern part of the ocean, where biological productivity is very high due to the dynamics of coastal waters, abundance of food, good lighting, shallow depths and the peculiar structure of the bottom. The catch of ocean gifts here is carried out by Belgium, Denmark, France, Finland, Germany, Greece, Iceland, the Netherlands, Norway, Great Britain, Poland, Portugal, Sweden, Spain and the CIS countries. Maximum seafood catches were in the 80s. XX century and amounted to about 12 million tons. The species composition of the catch is as follows: mackerel, pollock, catfish, perch, herring, sprat, flounder, crab, lobster, lobster, 5 types of shrimp, squid, snails, oysters, scallops, brown and red algae.
In tropical latitudes there is also fishing, although less abundant. The main objects are tuna, some types of sharks, swordfish, lobsters, shrimp, squid, turtles, shellfish, etc. The productivity of the ocean here is low, but in general, in terms of species composition, the catches are 7 times richer than in temperate latitudes.
Until the end of the 50s. XX century The Atlantic Ocean led the way in fish production. But years of overfishing have taken their toll on its resources, and the Pacific Ocean has taken first place.