The Atlantic Ocean is the second largest ocean on Earth after the Pacific Ocean, located between Greenland and Iceland in the north, Europe and Africa in the east, North and South America in the west, and Antarctica in the south.

The area is 91.6 million km², of which about a quarter falls on the inland seas. The area of ​​coastal seas is small and does not exceed 1% of the total water area. The volume of water is 329.7 million km³, which is equal to 25% of the volume of the World Ocean. The average depth is 3736 m, the greatest is 8742 m (Puerto Rico Trench). The average annual salinity of the ocean waters is about 35 ‰. The Atlantic Ocean has a strongly indented coastline with a pronounced division into regional water areas: seas and bays.

The name comes from the name of the titan Atlas (Atlanta) in Greek mythology.

Characteristics:

• Area - 91.66 million km²
• Volume - 329.66 million km³
• The greatest depth - 8742 m
• Average depth - 3736 m

Etymology

The name of the ocean is first encountered in the 5th century BC. e. in the writings of the ancient Greek historian Herodotus, who wrote that "the sea with the pillars of Hercules is called Atlantis (ancient Greek Ἀτλαντίς - Atlantis)". The name comes from the ancient Greek myth of Atlanta, a titan holding the vault of heaven on his shoulders at the extreme western point of the Mediterranean. The Roman scientist Pliny the Elder in the 1st century used the modern name Oceanus Atlanticus (lat. Oceanus Atlanticus) - “Atlantic Ocean”. At different times, separate parts of the ocean were called the Western Ocean, the North Sea, the Outer Sea. Since the middle of the 17th century, the Atlantic Ocean has become the only name referring to the entire water area.

Physical and geographical characteristics

General information

The Atlantic Ocean is the second largest. Its area is 91.66 million km², the volume of water is 329.66 million km³. It extends from the subarctic latitudes to Antarctica itself. The border with the Indian Ocean runs along the meridian of Cape Agulhas (20° E) to the coast of Antarctica (Queen Maud Land). The border with the Pacific Ocean is drawn from Cape Horn along the meridian 68 ° 04 'W. or the shortest distance from South America to the Antarctic Peninsula through the Drake Passage, from Ost Island to Cape Sternek. The border with the Arctic Ocean passes along the eastern entrance of the Hudson Strait, then through the Davis Strait and along the coast of Greenland Island to Cape Brewster, through the Denmark Strait to Cape Reidinupur on the island of Iceland, along its coast to Cape Gerpir, then to the Faroe Islands, then to Shetland islands and along 61 ° north latitude to the coast of the Scandinavian Peninsula. Sometimes the southern part of the ocean, with a northern boundary of 35 ° S. sh. (on the basis of the circulation of water and the atmosphere) up to 60 ° S. sh. (according to the nature of the bottom topography), they are attributed to the Southern Ocean, which is not officially distinguished.

Seas and bays

The area of ​​the seas, bays and straits of the Atlantic Ocean is 14.69 million km² (16% of the total ocean area), the volume is 29.47 million km³ (8.9%). Seas and main bays (clockwise): Irish Sea, Bristol Bay, North Sea, Baltic Sea (Gulf of Bothnia, Gulf of Finland, Gulf of Riga), Bay of Biscay, Mediterranean Sea (Alboran Sea, Balearic Sea, Ligurian Sea, Tyrrhenian Sea, Adriatic Sea, Ionian Sea, Aegean Sea), Sea of ​​Marmara, Black Sea, Sea of ​​\u200b\u200bAzov, Gulf of Guinea, Riiser-Larsen Sea, Lazarev Sea, Weddell Sea, Scotia Sea (the last four are sometimes referred to as the Southern Ocean), Caribbean Sea, Gulf of Mexico , Sargasso Sea, Gulf of Maine, Gulf of Saint Lawrence, Labrador Sea.

Islands

The largest islands and archipelagos of the Atlantic Ocean: the British Isles (Great Britain, Ireland, the Hebrides, Orkney Islands, Shetland Islands), the Greater Antilles (Cuba, Haiti, Jamaica, Puerto Rico, Huventud), Newfoundland, Iceland, the Tierra del Fuego archipelago (Fire Land, Oste, Navarino), Marajo, Sicily, Sardinia, Lesser Antilles (Trinidad, Guadeloupe, Martinique, Curacao, Barbados, Grenada, St. Vincent, Tobago), Falkland (Malvinas) Islands (East Falkland (Soledad), West Falkland (Gran Malvina)), Bahamas (Andros, Grand Inagua, Grand Bahama), Cape Breton, Cyprus, Corsica, Crete, Anticosti, Canary Islands (Tenerife, Fuerteventura, Gran Canaria), Zeeland, Prince Edward, Balearic Islands (Mallorca), South Georgia, Long Island, Moonsund Archipelago (Saaremaa, Hiiumaa), Cape Verde Islands, Euboea, Southern Sporades (Rhodes), Gotland, Funen, Cyclades, Azores, Ionian Islands, South Shetland Islands, B Yoko, Bijagos Islands, Lesvos, Aland Islands, Faroe Islands, Öland, Lolland, South Orkney Islands, Sao Tome, Madeira Islands, Malta, Principe, Saint Helena, Ascension, Bermuda.

History of ocean formation

The Atlantic Ocean was formed in the Mesozoic as a result of the split of the ancient supercontinent Pangea into the southern continent of Gondwana and northern Laurasia. As a result of the multidirectional movement of these continents at the very end of the Triassic, it led to the formation of the first oceanic lithosphere of the current North Atlantic. The resulting rift zone was the western continuation of the rift crack in the Tethys Ocean. The Atlantic basin at an early stage of its development was formed as a connection of two large ocean basins of the Tethys Ocean in the east and the Pacific Ocean in the west. Further growth of the Atlantic Ocean basin will take place due to the reduction in the size of the Pacific Ocean. In the early Jurassic, Gondwana began to split into Africa and South America, and the oceanic lithosphere of the modern South Atlantic was formed. During the Cretaceous, Laurasia split apart, and the separation of North America from Europe began. At the same time, Greenland, shifting to the north, broke away from Scandinavia and Canada. During the last 40 million years and up to the present time, the opening of the Atlantic Ocean basin continues along a single rift axis located approximately in the middle of the ocean. Movement today tectonic plates continues. In the South Atlantic, the divergence of the African and South American plates continues at a rate of 2.9-4 cm per year. In the Central Atlantic, the African, South American and North American plates diverge at a rate of 2.6-2.9 cm per year. In the North Atlantic, the spreading of the Eurasian and North American plates continues at a rate of 1.7-2.3 cm per year. The North American and South American plates move to the west, the African to the northeast, and the Eurasian to the southeast, forming a compression belt in the Mediterranean Sea.

Geological structure and bottom topography

Underwater margins of the continents

Significant areas of the shelf are confined to the northern hemisphere and are adjacent to the coasts of North America and Europe. In Quaternary times, most of the shelf was subjected to continental glaciation, which formed relic glacial landforms. Another element of the relict relief of the shelf is flooded river valleys found in almost all shelf regions of the Atlantic Ocean. Relic continental deposits are widespread. Off the coast of Africa and South America, the shelf occupies smaller areas, but in the southern part of South America it expands significantly (Patagonian shelf). Tidal currents have formed sandy ridges, which are the most widespread of modern subaqueous landforms. They are very characteristic of the shelf North Sea, they are found in large numbers in the English Channel, as well as on the shelves of North and South America. In equatorial-tropical waters (especially in the Caribbean Sea, on the Bahamas, off the coast of South America), coral reefs are diverse and widely represented.

Continental slopes in most areas of the Atlantic Ocean are expressed as steep slopes, sometimes having a stepped profile and deeply dissected by submarine canyons. In some areas, continental slopes are supplemented by marginal plateaus: Blake, São Paulo, Falkland on the American submarine margins; Podkupain and Goban on the underwater outskirts of Europe. The blocky structure is the Farrero-Iceland threshold, which extends from Iceland to the North Sea. In the same region is the Rokkol Upland, which is also a submerged part of the underwater part of the European subcontinent.

The continental foot, for most of its length, is an accumulation plain lying at a depth of 3-4 km and composed of a thick (several kilometers) thickness of bottom sediments. Three rivers of the Atlantic Ocean are among the ten largest in the world - Mississippi (solid runoff 500 million tons per year), Amazon (499 million tons) and Orange (153 million tons). The total volume of sedimentary material carried annually into the Atlantic Ocean basin by only 22 of its main rivers is more than 1.8 billion tons. Large fans of turbidity flows are located in certain areas of the continental foot, among them the most significant fans of the submarine canyons of the Hudson, Amazon, Rhone (in the Mediterranean), Niger, Congo. Along the North American continental margin, due to the bottom runoff of cold Arctic waters along the continental foot, giant accumulation landforms are formed in a southerly direction (for example, the "sedimentary ridges" of Newfoundland, Blake-Bahama and others).

transition zone

Transitional zones in the Atlantic Ocean are represented by areas: the Caribbean, the Mediterranean and the area of ​​the Scotia Sea or the South Sandwich.

The Caribbean region includes: the Caribbean Sea, the deep-water part of the Gulf of Mexico, island arcs and deep-sea trenches. The following island arcs can be distinguished in it: Cuban, Cayman-Siera-Maestra, Jamaica-South Haiti, outer and inner arcs of the Lesser Antilles. In addition, the underwater height of Nicaragua, the Beata and Aves ridges are distinguished here. The Cuban arc has a complex structure and has a Laramian age of folding. Its continuation is the northern cordillera of the island of Haiti. The Cayman-Siera Maestra fold structure, which is of Miocene age, begins with the Maya mountains on the Yucatan Peninsula, then continues in the form of the Cayman submarine ridge and the Sierra Maestra mountain range of Southern Cuba. The Little Antilles arc includes a number of volcanic formations (including three volcanoes, for example, Montagne Pele). The composition of the eruption products: andesites, basalts, dacites. The outer ridge of the arc is limestone. From the south, the Caribbean Sea is bordered by two parallel young ridges: the arc of the Leeward Islands and the mountain range of the Caribbean Andes, passing to the east into the islands of Trinidad and Tobago. Island arcs and underwater ridges divide the bottom of the Caribbean Sea into several basins, which are leveled by a thick layer of carbonate bottom sediments. The deepest of them is Venezuelan (5420 m). There are also two deep-water trenches - Cayman and Puerto Rico (with the greatest depth of the Atlantic Ocean - 8742 m).

The areas of the Scotia Ridge and the South Sandwich Islands are borderlands - sections of the underwater continental margin, fragmented by tectonic movements of the earth's crust. The island arc of the South Sandwich Islands is complicated by a number of volcanoes. From the east, it adjoins the South Sandwich Deep Trench with a maximum depth of 8228 m. The mountainous and hilly topography of the bottom of the Scotia Sea is associated with the axial zone of one of the branches of the mid-ocean ridge.

In the Mediterranean Sea, there is a wide distribution of the continental crust. The suboceanic crust is developed only in spots in the deepest basins: Balearic, Tyrrhenian, Central and Cretan. The shelf is significantly developed only within the Adriatic Sea and the Sicilian threshold. The mountainous folded structure connecting the Ionian Islands, Crete and the islands to the east of the latter is an island arc, which is bounded from the south by the Hellenic Trench, in turn framed by the rise of the East Mediterranean Swell from the south. The bottom of the Mediterranean Sea in the geological section is composed of salt-bearing strata of the Messinian stage (Upper Miocene). The Mediterranean Sea is a seismic zone. Several active volcanoes have been preserved here (Vesuvius, Etna, Santorini).

Mid-Atlantic Ridge

The meridional Mid-Atlantic Ridge divides the Atlantic Ocean into eastern and western parts. It begins off the coast of Iceland under the name of the Reykjanes Range. Its axial structure is formed by a basalt ridge, rift valleys are poorly expressed in the relief, but active volcanoes are known on the flanks. At a latitude of 52-53 ° N the mid-ocean ridge is crossed by the transverse zones of the Gibbs and Reykjanes faults. Behind them begins the Mid-Atlantic Ridge with a clearly defined rift zone and rift valleys with numerous transverse faults and deep grabens. At latitude 40°N the mid-ocean ridge forms the Azores volcanic plateau, with numerous above-water (forming islands) and underwater active volcanoes. To the south of the Azores Plateau, in the rift zone, under calcareous muds 300 m thick, basalts occur, and beneath them is a blocky mixture of ultrabasic and basic rocks. In this area, modern violent volcanic and hydrothermal activity is observed. In the equatorial part, the North Atlantic Ridge is divided by a large number of transverse faults into a number of segments experiencing significant (up to 300 km) lateral displacements relative to each other. Near the equator, the Romansh depression is connected with deep-water faults with depths up to 7856 m.

The South Atlantic Ridge has a meridional strike. Rift valleys are well expressed here, the number of transverse faults is less, so this ridge looks more monolithic compared to the North Atlantic Ridge. In the south and middle parts Ridge stand out volcanic plateau of the Ascension, the islands of Tristan da Cunha, Gough, Bouvet. The plateau is confined to active and recently active volcanoes. From Bouvet Island, the South Atlantic Ridge turns to the east, goes around Africa and merges with the West Indian Median Ridge in the Indian Ocean.

Ocean bed

The Mid-Atlantic Ridge divides the bed of the Atlantic Ocean into two almost equal parts. In the western part, mountain structures: the Newfoundland Range, the Baracuda Range, the Ceara and Rio Grande rises divide the ocean bed into basins: Labrador, Newfoundland, North American, Guiana, Brazilian, Argentine. To the east of the mid-ocean ridge, the bed is divided by the underwater base of the Canary Islands, the uplift of the Cape Verde Islands, the Guinean uplift and the Whale Ridge into basins: Western European, Iberian, North African, Cape Verde, Sierra Leone, Guinea, Angolan, Cape. In the basins, flat abyssal plains are widespread, composed mainly of calcareous biogenic, as well as terrigenous material. Over most of the area of ​​the ocean floor, the thickness of precipitation is more than 1 km. Under the sedimentary rocks, a layer was found represented by volcanic rocks and compacted sedimentary rocks.

Abyssal hills are widespread along the periphery of mid-ocean ridges in areas of basins remote from the submarine margins of continents. About 600 mountains are located within the ocean floor. A large group of seamounts is confined to the Bermuda Plateau (in the North American Basin). There are several large submarine valleys, of which the most significant are the Hazen and Maury valleys in the northern part of the Atlantic Ocean floor, stretching on both sides of the Mid-Ocean Ridge.

Bottom sediments

The sediments of the shallow part of the Atlantic Ocean are mostly represented by terrigenous and biogenic sediments, and occupy 20% of the ocean floor area. Of the deep-sea deposits, calcareous foraminiferal silts are the most common (65% of the ocean floor area). In the Mediterranean and Caribbean Seas, in the southern zone of the South Atlantic Ridge, pteropod deposits have become widespread. Deep-sea red clay occupies about 20% of the ocean floor area and is confined to the deepest parts of oceanic basins. Radilarian muds are found in the Angolan Basin. In the southern part of the Atlantic, siliceous diatom deposits are presented with an authigenic silica content of 62-72%. In the zone of the Current of the Western Winds, a continuous field of diatomaceous oozes extends, with the exception of the Drake Passage. In some basins of the ocean floor, terrigenous silts and pelites are significantly developed. Terrigenous deposits at abyssal depths are characteristic of the North Atlantic, Hawaiian, and Argentine basins.

Climate

The variety of climatic conditions on the surface of the Atlantic Ocean is determined by its large meridional extent and the circulation of air masses under the influence of four main atmospheric centers: Greenland and Antarctic highs, Icelandic and Antarctic lows. In addition, two anticyclones constantly operate in the subtropics: Azores and South Atlantic. They are separated by an equatorial region of low pressure. This distribution of baric regions determines the system of prevailing winds in the Atlantic. The greatest influence on the temperature regime of the Atlantic Ocean is exerted not only by its large meridional extent, but also by water exchange with the Arctic Ocean, the seas of the Antarctic and the Mediterranean Sea. Surface waters are characterized by their gradual cooling as they move away from the equator to high latitudes, although the presence of powerful currents causes significant deviations from zonal temperature regimes.

All the climatic zones of the planet are represented in the vastness of the Atlantic. Tropical latitudes are characterized by slight seasonal temperature fluctuations (average - 20 ° C) and heavy rainfall. North and south of the tropics are subtropical belts with more noticeable seasonal (from 10 °C in winter to 20 °C in summer) and daily temperature fluctuations; Precipitation here falls mainly in summer. Frequent occurrence in the subtropical zone - tropical hurricanes. In these monstrous atmospheric eddies, wind speeds reach several hundred kilometers per hour. The most powerful tropical hurricanes rage in the Caribbean: for example, in the Gulf of Mexico and the West Indies. West Indian tropical hurricanes form in the western part of the ocean around 10-15°N. and move to the Azores and Ireland. Further to the north and south, the subtropical zones follow, where in the coldest month the temperature drops to 10 ° C, and in winter cold air masses from the polar regions low pressure bring abundant rainfall. In temperate latitudes, the average temperature of the warmest month is kept within 10-15 °C, and the coldest -10 °C. Significant diurnal temperature fluctuations are also noted here. The temperate zone is characterized by fairly even precipitation throughout the year (about 1,000 mm), reaching a maximum in the autumn-winter period, and frequent fierce storms, for which the southern temperate latitudes are nicknamed the "roaring forties". The 10 °C isotherm defines the boundaries of the Northern and Southern Subpolar Belts. In the Northern Hemisphere, this boundary runs in a wide strip between 50°N. (Labrador) and 70°N. (Northern Norway coast). In the Southern Hemisphere, the subpolar zone begins closer to the equator - approximately 45-50°S. The most low temperature(-34 °C) has been recorded in the Weddell Sea.

Hydrological regime

Surface water circulation

Powerful carriers of thermal energy are circular surface currents, located on both sides of the equator: such, for example, are the North Trade Wind and South Trade Wind currents that cross the ocean from east to west. The Northern Tradewind Current near the Lesser Antilles is divided: into a northern branch continuing northwest along the shores of the Greater Antilles (Antilles current) and into a southern branch leaving through the straits of the Lesser Antilles into the Caribbean Sea, and then flows through the Yucatan Strait into the Gulf of Mexico, and leaves it through the Florida Strait, forming the Florida Current. The latter has a speed of 10 km / h and gives rise to the famous Gulf Stream. Gulf Stream, following along American coast, at 40°N as a result of the influence of westerly winds and the Coriolis force, it acquires an easterly and then a northeasterly direction and is called the North Atlantic Current. The main flow of waters of the North Atlantic Current passes between Iceland and the Scandinavian Peninsula and flows into the Arctic Ocean, softening the climate in the European sector of the Arctic. Two powerful streams of cold desalinated water flow out of the Arctic Ocean - the East Greenland Current, which runs along the eastern coast of Greenland, and the Labrador Current, which envelops Labrador, Newfoundland and penetrates south to Cape Hatteras, pushing the Gulf Stream from the coast of North America.

The South Equatorial Current partially enters the northern hemisphere, and at Cape San Roque it is divided into two parts: one of them goes south, forming the Brazilian Current, the other turns north, forming the Guiana Current, which goes into the Caribbean Sea. The Brazilian Current in the La Plata region meets the cold Falkland Current (an offshoot of the West Wind Current). Near the southern end of Africa, the cold Benguela Current branches off from the West Wind Current and, moving along the coast of South West Africa, gradually deviates to the west. In the southern part of the Gulf of Guinea, this current closes the anticyclonic circulation of the South Trade Wind Current.

There are several layers of deep currents in the Atlantic Ocean. A powerful countercurrent passes under the Gulf Stream, the main core of which lies at a depth of up to 3500 m, with a speed of 20 cm/s. The countercurrent flows in a narrow stream in the lower part of the continental slope, the formation of this current is associated with the bottom runoff of cold waters from the Norwegian and Greenland seas. In the equatorial zone of the ocean, the Lomonosov subsurface current has been discovered. It starts from the Antilo-Guiana countercurrent and reaches the Gulf of Guinea. The powerful deep Louisiana current is observed in the eastern part of the Atlantic Ocean, formed by the bottom runoff of saltier and warmer Mediterranean waters through the Strait of Gibraltar.

The highest tide values ​​are confined to the Atlantic Ocean, which are noted in the fjord bays of Canada (in Ungava Bay - 12.4 m, in Frobisher Bay - 16.6 m) and Great Britain (up to 14.4 m in Bristol Bay). The highest tide in the world is recorded in the Bay of Fundy, on the east coast of Canada, where the maximum tide reaches 15.6-18 m.

Temperature, salinity, ice formation

The temperature fluctuation of Atlantic waters during the year is not large: in the equatorial-tropical zone - no more than 1-3 °, in the subtropics and temperate latitudes - within 5-8 °, in subpolar latitudes - about 4 ° in the north and not more than 1 ° on South. The warmest waters are in the equatorial and tropical latitudes. For example, in the Gulf of Guinea, the temperature in the surface layer does not drop below 26 °C. In the northern hemisphere, north of the tropics, the temperature of the surface layer decreases (at 60°N it is 10°C in summer). In the southern hemisphere, temperatures rise much faster and by 60°S. hover around 0°C. In general, the ocean in the southern hemisphere is colder than in the northern. In the northern hemisphere, the western part of the ocean is colder than the eastern one, and vice versa in the southern hemisphere.

The highest salinity of surface waters in open ocean observed in the subtropical zone (up to 37.25 ‰), and the maximum in the Mediterranean Sea is 39 ‰. In the equatorial zone, where maximum amount precipitation, salinity decreases to 34 ‰. A sharp desalination of water occurs in the estuarine areas (for example, at the mouth of La Plata 18-19 ‰).

Ice formation in the Atlantic Ocean occurs in the Greenland and Baffin Seas and Antarctic waters. The main source of icebergs in the South Atlantic is the Filchner Ice Shelf in the Weddell Sea. On the Greenland coast, icebergs are produced by outlet glaciers, such as the Jakobshavn Glacier near Disko Island. Floating ice in the northern hemisphere reaches 40°N in July. In the southern hemisphere floating ice are present throughout the year up to 55°S, reaching their maximum distribution in September-October. The total removal from the Arctic Ocean is estimated at an average of 900,000 km³/year, from the surface of Antarctica - 1630 km³/year.

water masses

Under the influence of wind and convective processes, vertical mixing of water occurs in the Atlantic Ocean, covering a surface thickness of 100 m in the southern hemisphere and up to 300 m in the tropics and equatorial latitudes. Below the layer of surface waters, outside the subantarctic zone, in the Atlantic, there is Antarctic intermediate water, which is almost universally identified with an intermediate minimum of salinity and is characterized by a higher content compared to the overlying waters. nutrients, and extends to the north to the area of ​​20°N. at depths of 0.7-1.2 km.

A feature of the hydrological structure of the eastern part of the North Atlantic is the presence of an intermediate Mediterranean water mass, which gradually descends to a depth of 1000 to 1250 m, turning into a deep water mass. In the southern hemisphere this water mass drops to 2500-2750 m and wedged south of 45°S. The main feature of these waters is high salinity and temperature in relation to the surrounding waters. In the bottom layer of the Strait of Gibraltar, salinity is up to 38 ‰, temperature is up to 14 °C, but already in the Gulf of Cadiz, where Mediterranean waters reach the depths of their existence in the Atlantic Ocean, their salinity and temperature, as a result of mixing with background waters, decrease to 36 ‰ and 12-13°C, respectively. At the periphery of the distribution area, its salinity and temperature are, respectively, 35 ‰ and about 5°C. Under the Mediterranean water mass in the northern hemisphere, the North Atlantic deep water is formed, which sinks as a result of winter cooling of relatively saline waters in the North European Basin and the Labrador Sea to a depth of 2500-3000 m in the northern hemisphere and to 3500-4000 m in the southern hemisphere, reaching to about 50°S The North Atlantic deep water differs from the above and below Antarctic waters in its increased salinity, temperature and oxygen content, as well as the reduced content of nutrients.

The Antarctic bottom water mass is formed on the Antarctic slope by mixing cold and heavy Antarctic shelf water with lighter, warmer and more saline Circumpolar Deep Waters. These waters, spreading from the Weddell Sea, passing through all orographic obstacles up to 40 ° N, have a temperature of less than minus 0.8 ° C in the north of this sea, 0.6 ° C at the equator and 1.8 ° C near Bermuda. The Arctic bottom water mass has lower salinity values ​​compared to the overlying waters, and in the South Atlantic it is characterized by an increased content of biogenic elements.

Flora and fauna

The bottom flora of the northern part of the Atlantic is represented by brown (mainly fucoids, and in the subtidal zone - kelp and alaria) and red algae. In the tropical zone, green (caulerpa), red (calcareous lithotamnia) and brown algae (sargasso) predominate. In the southern hemisphere, bottom vegetation is mainly represented by kelp. Phytoplankton of the Atlantic Ocean has 245 species: peridine, coccolithophorids, diatoms. The latter have a clearly defined zonal distribution; their maximum number lives in temperate latitudes of the northern and southern hemispheres. The most dense population of diatoms is in the strip of the Current of the Western Winds.

The distribution of the fauna of the Atlantic Ocean has a pronounced zonal character. In the subantarctic and antarctic waters, notothenia, blue whiting and others are of commercial importance from fish. Benthos and plankton in the Atlantic are poor in both species and biomass. In the subantarctic zone and in the adjacent zone of the temperate zone, the biomass reaches its maximum. Copepods and pteropods predominate in zooplankton, while whales (blue whales), pinnipeds, and nototheniids predominate in nekton. In the tropical zone, zooplankton is represented by numerous species of foraminifera and pteropods, several species of radiolarians, copepods, larvae of molluscs and fish, as well as siphonophores, various jellyfish, large cephalopods (squids), and octopuses among benthal forms. Commercial fish are represented by mackerel, tuna, sardines, in areas of cold currents - anchovies. Corals are confined to tropical and subtropical zones. The temperate latitudes of the northern hemisphere are characterized by abundant life with a relatively small variety of species. From commercial fish greater value have herring, cod, haddock, halibut, sea bass. The most common zooplankton species are foraminifera and copepods. The greatest abundance of plankton is in the area of ​​the Newfoundland Bank and the Norwegian Sea. The deep-sea fauna is represented by crustaceans, echinoderms, specific fish species, sponges, and hydroids. Several species of endemic polychaetes, isopods, and holothurians have been found in the Puerto Rico Trench.

Environmental problems

The Atlantic Ocean has been a place of intensive sea fishing and hunting since time immemorial. A sharp increase in capacity and a revolution in fishing technology have led to alarming proportions. With the invention of the harpoon gun in the North Atlantic, whales were largely exterminated as early as the end of the 19th century. In connection with the massive development of pelagic whaling in Antarctic waters in the middle of the 20th century, whales here were also close to complete extermination. Since the 1985-1986 season, the International Whaling Commission has introduced a complete moratorium on commercial whaling of any kind. In June 2010, at the 62nd meeting of the International Whaling Commission, under pressure from Japan, Iceland and Denmark, the moratorium was suspended.

The explosion on the Deepwater Horizon oil platform, owned by the British company BP, which occurred on April 20, 2010 is considered the largest environmental catastrophe that has ever taken place at sea. As a result of the accident, about 5 million barrels of crude oil spilled into the waters of the Gulf of Mexico, polluting 1,100 miles of coastline. The authorities introduced a ban on fishing, more than a third of the entire water area of ​​the Gulf of Mexico is closed for fishing. As of November 2, 2010, 6,814 dead animals have been collected, including 6,104 birds, 609 sea turtles, 100 dolphins and other mammals, and 1 other reptile. According to the Office of Specially Protected Resources of the National Oceanic and Atmospheric Administration, in 2010-2011, an increase in the mortality of cetaceans in the northern Gulf of Mexico was several times higher than in previous years (2002-2009).

A large garbage patch of plastic and other waste has formed in the Sargasso Sea, formed by ocean currents, gradually concentrating garbage thrown into the ocean in one area.

In some areas of the Atlantic Ocean, radioactive contamination is observed. Waste from nuclear power plants and research centers are discharged into rivers and coastal waters of the seas, and sometimes into the deep parts of the ocean. The water areas of the Atlantic Ocean heavily contaminated with radioactive waste include the North, Irish, Mediterranean Seas, the Gulf of Mexico, the Bay of Biscay and the Atlantic coast of the United States. In 1977 alone, 7180 containers containing 5650 tons of radioactive waste were dumped into the Atlantic. The US Environmental Protection Agency has reported seabed contamination 120 miles east of the Maryland-Delaware border. For 30 years, 14,300 cemented containers were buried there, which contained plutonium and cesium, radioactive contamination exceeded "expected" by 3-70 times. In 1970, the United States sank the Russell Brig, 500 km off the coast of Florida, carrying 68 tons of nerve gas (sarin) placed in 418 concrete containers. In 1972, in the waters of the ocean north of the Azores, Germany flooded 2,500 metal drums with industrial waste containing potent cyanide poisons. There are cases of rapid destruction of containers in the relatively shallow waters of the North and Irish Seas and the English Channel with the most detrimental consequences for the fauna and flora of the waters. 4 nuclear submarines sank in the waters of the North Atlantic: 2 Soviet (in the Bay of Biscay and the open part of the ocean) and 2 American (off the coast of the United States and in the open part of the ocean).

States of the Atlantic Ocean

On the shores of the Atlantic Ocean and its constituent seas there are states and dependent territories:

• In Europe (from north to south): Iceland, Norway, Sweden, Finland, Russian Federation, Estonia, Latvia, Lithuania, Poland, Federal Republic of Germany, Denmark, Netherlands, Belgium, Great Britain, Ireland, Isle of Man (UK property), Jersey (UK property), France, Spain, Portugal, Gibraltar (UK property), Italy, Malta, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Albania, Greece, Turkey, Bulgaria, Romania, Ukraine, Abkhazia (not recognized by the UN), Georgia;
• In Asia: Cyprus, Turkish Republic Northern Cyprus (not recognized by the UN), Akrotiri and Dhekelia (possession of Great Britain), Syria, Lebanon, Israel, the Palestinian Authority (not recognized by the UN);
• In Africa: Egypt, Libya, Tunisia, Algeria, Morocco, Saharan Arab Democratic Republic (not recognized by the UN), Mauritania, Senegal, Gambia, Cape Verde, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Côte d'Ivoire , Ghana, Togo, Benin, Nigeria, Cameroon, Equatorial Guinea, Sao Tome and Principe, Gabon, Republic of the Congo, Angola, Democratic Republic of the Congo, Namibia, Republic of South Africa, Bouvet Island (Norwegian possession), Saint Helena, Ascension and Tristan da Cunha (British possession);
• AT South America(from south to north): Chile, Argentina, South Georgia and the South Sandwich Islands (UK), Falkland Islands (UK), Uruguay, Brazil, Suriname, Guyana, Venezuela, Colombia, Panama;
• In the Caribbean: US Virgin Islands (U.S.), Anguilla (UK), Antigua and Barbuda, Bahamas, Barbados, British Virgin Islands (UK), Haiti, Grenada, Dominica, Dominican Republic, Cayman Islands (UK) , Cuba, Montserrat (UK), Navassa (US), Puerto Rico (US), Saint Vincent and the Grenadines, Saint Kitts and Nevis, St. Lucia, Turks and Caicos (UK), Trinidad and Tobago , Jamaica;
• In North America: Costa Rica, Nicaragua, Honduras, Guatemala, Belize, Mexico, United States of America, Bermuda (UK), Canada.

History of the exploration of the Atlantic Ocean by Europeans

Long before the era of great geographical discoveries, numerous ships plied the Atlantic. As early as 4000 BC, the peoples of Phoenicia were engaged in maritime trade with the inhabitants of the islands of the Mediterranean Sea. At a later time, from the 6th century BC, the Phoenicians, according to the Greek historian Herodotus, made campaigns around Africa, and through the Strait of Gibraltar and around the Iberian Peninsula reached british isles. By the 6th century BC, Ancient Greece, having a military merchant fleet that was huge at that time, sailed to the shores of England and Scandinavia, in the Baltic Sea and to the western coast of Africa. In X-XI Art. new page the Vikings entered the study of the northern part of the Atlantic Ocean. According to most researchers of pre-Columbian discoveries, the Scandinavian Vikings were the first to cross the ocean more than once, reaching the shores of the American continent (they called it Vinland) and discovering Greenland and Labrador.

In the 15th century, Spanish and Portuguese navigators began to make long voyages in search of routes to India and China. In 1488, the Portuguese expedition of Bartolomeu Dias reached the Cape of Good Hope and circled Africa from the south. In 1492, the expedition of Christopher Columbus mapped many islands of the Caribbean and the huge mainland, later called America. In 1497, Vasco da Gama passed from Europe to India, rounding Africa from the south. In 1520, Ferdinand Magellan, during the first circumnavigation of the world, passed through the Strait of Magellan from the Atlantic to the Pacific Ocean. At the end of the 15th century, the rivalry between Spain and Portugal for dominance in the Atlantic escalated so much that the Vatican was forced to intervene in the conflict. In 1494, an agreement was signed, which along the 48-49 ° west longitude established the so-called. papal meridian. All lands to the west of it were given to Spain, and to the east - to Portugal. In the 16th century, as colonial wealth was being developed, the waves of the Atlantic began to regularly surf the ships carrying gold, silver, precious stones, pepper, cocoa and sugar to Europe. Weapons, fabrics, alcohol, food and slaves for cotton and sugar cane plantations were delivered to America in the same way. It is not surprising that in the XVI-XVII centuries. piracy and privateering flourished in these parts, and many famous pirates, such as John Hawkins, Francis Drake and Henry Morgan, inscribed their names in history. The southern border of the Atlantic Ocean (continent of Antarctica) was discovered in 1819-1821 by the first Russian Antarctic expedition of F. F. Bellingshausen and M. P. Lazarev.

The first attempts to study the seabed were made in 1779 near the coast of Denmark, and the first Russian round-the-world expedition under the command of naval officer Ivan Krusenstern laid the foundation for serious scientific research in 1803-1806. Temperature measurements at various depths were carried out by J. Cook (1772), O. Saussure (1780), and others. Participants of subsequent trips took temperature measurements and specific gravity water at different depths, took samples of water transparency and established the presence of undercurrents. The collected material made it possible to draw up a map of the Gulf Stream (B. Franklin, 1770), a map of the depths of the northern part of the Atlantic Ocean (M.F. Maury, 1854), as well as maps of the winds and currents of the ocean (M.F. Maury, 1849-1860) and to carry out other research.

From 1872 to 1876, the first scientific ocean expedition took place on the English sailing-steam corvette Challenger, new data were obtained on the composition of the ocean waters, on the flora and fauna, on the bottom topography and soils, the first map of the depths of the ocean was compiled and the first collection was collected. deep-sea animals, as a result of which extensive material was collected, published in 50 volumes. It was followed by expeditions on the Russian sail-propeller corvette Vityaz (1886-1889), on the German ships Valdivia (1898-1899) and Gauss (1901-1903) and others. The most important work was carried out on the British ship Discovery II (since 1931), thanks to which oceanographic and hydrobiological studies were carried out in the open part of the South Atlantic at great depths. Within the framework of the International Geophysical Year (1957-1958), international forces (especially the USA and the USSR) carried out research, as a result of which new bathymetric and marine navigation charts Atlantic Ocean. In 1963-1964, the Intergovernmental Oceanographic Commission conducted a major expedition to explore the equatorial and tropical zones of the ocean, in which the USSR took part (on the ships Vityaz, Mikhail Lomonosov, Akademik Kurchatov and others), the USA, Brazil and others countries.

In recent decades, numerous measurements of the ocean have been carried out from space satellites. The result was released in 1994 by the American National Center geophysical data bathymetric atlas of the oceans with a map resolution of 3-4 km and a depth accuracy of ±100 m.

Economic importance

Fishing and marine industries

The Atlantic Ocean provides 2/5 of the world catch and its share decreases over the years. In subantarctic and antarctic waters, notothenia, blue whiting and others are of commercial importance, in the tropical zone - mackerel, tuna, sardine, in areas of cold currents - anchovies, in temperate latitudes of the northern hemisphere - herring, cod, haddock, halibut, sea bass. In the 1970s, due to overfishing of some species of fish, the volume of fishing fell sharply, but after the introduction of strict limits, fish stocks are gradually restored. Several international fisheries conventions operate in the Atlantic Ocean basin, aiming at efficient and rational use biological resources, based on the application of scientifically based measures to regulate the fishery.

Transport routes

The Atlantic Ocean occupies a leading position in world shipping. Most of paths leading from Europe to North America. The main navigable straits of the Atlantic Ocean: the Bosphorus and the Dardanelles, Gibraltar, the English Channel, Pas de Calais, the Baltic straits (Skagerrak, Kattegat, Øresund, Greater and Lesser Belt), Danish, Florida. The Atlantic Ocean is connected to the Pacific Ocean by the artificial Panama Canal dug between North and South America along the Isthmus of Panama, as well as to the Indian Ocean by the artificial Suez Canal through the Mediterranean Sea. The largest ports: St. Petersburg (general cargo, oil products, metals, timber, containers, coal, ore, chemical cargo, scrap metal), Hamburg (machinery and equipment, chemical products, raw materials for metallurgy, oil, wool, timber, food) , Bremen, Rotterdam (oil, natural gas, ores, fertilizers, equipment, food), Antwerp, Le Havre (oil, equipment), Felixstowe, Valencia, Algeciras, Barcelona, ​​Marseille (oil, ore, grain, metals, chemicals, sugar , fruits and vegetables, wine), Gioia-Tauro, Marsaxlokk, Istanbul, Odessa (raw sugar, containers), Mariupol (coal, ore, grain, containers, oil products, metals, timber, food), Novorossiysk (oil, ore, cement, grain, metals, equipment, food), Batumi (oil, general and bulk cargo, food), Beirut (export: phosphorites, fruits, vegetables, wool, timber, cement, import: cars, fertilizers, cast iron, Construction Materials, food), Port Said, Alexandria (export: cotton, rice, ores, import: equipment, metals, oil products, fertilizers), Casablanca (export: phosphorites, ores, citrus fruits, cork, food, import: equipment, fabrics, oil products ), Dakar (peanuts, dates, cotton, livestock, fish, ores, import: equipment, oil products, food), Cape Town, Buenos Aires (export: wool, meat, grain, leather, vegetable oil, linseed, cotton, import: equipment, iron ore, coal, oil, manufactured goods), Santos, Rio de Janeiro (export: iron ore, pig iron, coffee, cotton, sugar, cocoa beans, lumber, meat, wool, leather, import: oil products, equipment, coal, grain, cement, food), Houston (petroleum, grain, sulfur, equipment), New Orleans (ores, coal, building materials, cars, grain, rolling, equipment, coffee, fruit, food), Savannah , New York (general cargo, oil, chemicals, equipment, pulp, paper, coffee, sugar, metals), Monre eal (grain, oil, cement, coal, timber, metals, paper, asbestos, weapons, fish, wheat, equipment, cotton, wool).

Air traffic plays a leading role in passenger traffic between Europe and North America across the Atlantic Ocean. Most of the transatlantic lines run in the North Atlantic through Iceland and Newfoundland. Another message goes through Lisbon, Azores and Bermuda. The air route from Europe to South America passes through Lisbon, Dakar and further through the narrowest part of the Atlantic Ocean in Rio de Janeiro. Airlines from the US to Africa pass through the Bahamas, Dakar and Robertsport. On the coast of the Atlantic Ocean there are spaceports: Cape Canaveral (USA), Kourou (French Guiana), Alcantara (Brazil).

Minerals

Mining, primarily oil and gas, is carried out on the continental shelves. Oil is produced on the shelves of the Gulf of Mexico, the Caribbean Sea, the North Sea, the Bay of Biscay, the Mediterranean Sea, and the Gulf of Guinea. There is also natural gas production on the shelf of the North Sea. Sulfur is commercially mined in the Gulf of Mexico, and iron ore off the island of Newfoundland. Diamonds are mined from sea placers on the continental shelf of South Africa. The next most important group of mineral resources is formed by coastal deposits of titanium, zirconium, tin, phosphorites, monazite and amber. Coal, barite, sand, pebbles and limestone are also mined from the seabed.

Tidal power plants have been built on the shores of the seas of the Atlantic Ocean: La Rance on the Rance River in France, Annapolis in the Bay of Fundy in Canada, and Hammerfest in Norway.

Recreational resources

The recreational resources of the Atlantic Ocean are characterized by considerable diversity. The main countries of formation of outbound tourism in this region are formed in Europe (Germany, Great Britain, France, Italy, the Netherlands, Belgium, Austria, Sweden, the Russian Federation, Switzerland and Spain), North (USA and Canada) and South America. The main recreational areas: the Mediterranean coast of Southern Europe and North Africa, the coasts of the Baltic and Black Seas, the Florida peninsula, the islands of Cuba, Haiti, the Bahamas, areas of cities and urban agglomerations of the Atlantic coast of North and South America.

Recently, the popularity of such Mediterranean countries as Turkey, Croatia, Egypt, Tunisia and Morocco has been growing. Among the countries of the Atlantic Ocean with the largest flow of tourists (according to 2010 data from the World Tourism Organization) stand out: France (77 million visits per year), USA (60 million), Spain (53 million), Italy (44 million), Great Britain (28 million), Turkey (27 million), Mexico (22 million), Ukraine (21 million), Russian Federation (20 million), Canada (16 million), Greece (15 million), Egypt (14 million), Poland (12 million ), Netherlands (11 million), Morocco (9 million), Denmark (9 million), South Africa (8 million), Syria (8 million), Tunisia (7 million), Belgium (7 million), Portugal (7 million) , Bulgaria (6 million), Argentina (5 million), Brazil (5 million).

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

North Atlantic Ocean

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

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

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

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

The basin of the Atlantic Ocean is bordered by a shelf, the width of which varies. The shelf is cut through by deep gorges - the so-called. submarine canyons. Their origin is still a matter of controversy. According to one theory, the canyons were cut by rivers when the ocean level was below present. Another theory links their formation with the activity of turbidity currents. It has been suggested that turbidity currents are the main agent responsible for the deposition of sediments on the ocean floor and that it is they that cut submarine canyons.

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

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

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

Surface currents in the North Atlantic Ocean move clockwise. The main elements of this big system are the warm current of the Gulf Stream directed to the north, as well as the North Atlantic, Canary and Northern Equatorial (Equatorial) currents. The Gulf Stream follows from the Florida Strait and Cuba Island in a northerly direction along the coast of the USA and approximately 40°N. sh. deviates to the northeast, changing its name to the North Atlantic Current. This current divides into two branches, one of which follows the northeast along the coast of Norway and further into the Arctic Ocean. It is because of it that the climate of Norway and all of northwestern Europe is much warmer than would be expected at latitudes corresponding to the region stretching from Nova Scotia to southern Greenland. The second branch turns south and further southwest along the coast of Africa, forming the cold Canary Current. This current moves to the southwest and joins the North Equatorial Current, which heads west towards the West Indies, where it merges with the Gulf Stream. To the north of the North Equatorial Current is an area of ​​stagnant water, abundant in algae and known as the Sargasso Sea. Along the North Atlantic coast of North America, the cold Labrador Current passes from north to south, following from the Baffin Bay and the Labrador Sea and cooling the coast of New England.

South Atlantic Ocean

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

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

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

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

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

Physico-geographical essay. General information. In the north, the border of the Atlantic Ocean with the Arctic Ocean basin runs along the eastern entrance of the Hudson Strait, then through the Davis Strait and along the coast of Greenland Island to Cape Brewster, through the Denmark Strait to Cape Reidinupur on the island of Iceland, along its coast to Cape Gerpir (Terpire), 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 bounded 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 the line passing 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 of 68°04' west longitude or along the shortest distance from South America to the Antarctic Peninsula through the Drake Passage, from Oste Island to Cape Sternek. The southern part of the 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 papers propose the division of the Atlantic Ocean into the North and South Atlantic Oceans, but it is more common to consider it as a single ocean. The Atlantic Ocean is the most biologically productive of the oceans. It contains the longest underwater oceanic ridge - the Mid-Atlantic Ridge, the only sea that does not have solid shores, limited by currents - the Sargasso Sea; the Bay of Fundy with the highest tidal wave; The Black Sea with a unique hydrogen sulfide layer belongs to the Atlantic Ocean basin.

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

Seas. In the basin of the Atlantic Ocean 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, Cypriot, Ligurian, Tyrrhenian, Aegean) ; interisland - Irish and inland seas of the western coast of Scotland; marginal - Labrador, Northern, Sargasso, Caribbean, Scotia (Scotia), Weddell, Lazareva, the western part of Riiser-Larsen (see separate articles about the seas). The largest bays of the ocean: Biscay, Bristol, Guinean, Mexican, Maine, St. Lawrence.

Islands. Unlike other oceans, there are few seamounts, guyots and coral reefs in the Atlantic Ocean, and there are no coastal reefs. The total area of ​​the islands of the Atlantic Ocean is about 1070 thousand km2. The main groups of islands are located on the outskirts of the continents: British (Great Britain, Ireland, etc.) - the largest in area, Greater Antilles (Cuba, Haiti, Jamaica, etc.), Newfoundland, Iceland, the Tierra del Fuego archipelago (Land of Fire, Oste, Navarino ), Marajo, Sicily, Sardinia, Lesser Antilles, Falkland (Malvinas), Bahamas, etc. Small islands are found in the open ocean: Azores, Sao Paulo, Ascension, Tristan da Cunha, Bouvet (on the Mid-Atlantic Ridge) and others

coast. The coastline in the northern part of the Atlantic Ocean is strongly indented (see also the article Coast), almost all major inland seas and bays are located here, in the southern part of the Atlantic Ocean the coasts are slightly indented. The coasts of Greenland, Iceland and the coast of Norway are predominantly tectonic-glacial dissection of the fjord and fiard types. To the south, in Belgium, they give way to sandy shallow shores. Coast of Flanders mainly artificial origin(coastal dams, polders, canals, etc.). The shores of the island of Great Britain and the island of Ireland are abrasion-bay, high limestone cliffs alternate with sandy beaches and muddy lands. The Cherbourg Peninsula has rocky shores, 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 fencing off lagoons. Sandy beaches also border the shores of Western Sahara and Mauritania. To the south of Cape Zeleny there are leveled abrasion-bay shores with mangrove thickets. The western section of Côte d'Ivoire has an accumulative

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

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

The boundary of the continental shelf (shelf) of the Atlantic Ocean passes on average at depths of 100-200 m, its position can vary from 40-70 m (near Cape Hatteras and the Florida Peninsula) to 300-350 m (Weddell Cape). Shelf width from 15-30 km (northeast of Brazil, Iberian Peninsula) to several hundred km (North Sea, Gulf of Mexico, Newfoundland Bank). In high latitudes, the shelf relief 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 on the shelf are ice shelves. At low latitudes, the shelf surface is more even, especially in the areas where terrigenous material is carried out by rivers. It is crossed by transverse valleys, often turning into canyons of the continental slope.

The slope of the continental slope of the ocean averages 1-2° and varies from 1° (regions of Gibraltar, the Shetland Islands, parts of the coast of Africa, 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 dissected in places by steps, ledges and terraces of tectonic and accumulative origin and longitudinal canyons. At the foot of the continental slope, gently sloping hills up to 300 m high and shallow underwater valleys are often located.

In the middle part of the bottom of the Atlantic Ocean is the largest mountain system of the Mid-Atlantic Ridge. It extends from the island of Iceland to the island of Bouvet for 18,000 km. The width of the ridge is 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 uplifts. In the western part of the Atlantic Ocean, basins are distinguished from north to south: Labrador (with depths of 3000-4000 m); Newfoundland (4200-5000 m); the North American basin (5000-7000 m), which includes the 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; Argentine (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), Zeleniy Cape (up to 6000 m), Sierra Leone (about 5000 m), Guinean (over 5000 m ), Angolan (up to 6000 m), Cape (over 5000 m) with the abyssal plains of the same name. To the south is the African-Antarctic Basin with the abyssal Weddell Plain. The bottoms of deep-water basins at the foot of the Mid-Atlantic Ridge are occupied by the zone of abyssal hills. The basins are separated by the Bermuda, Rio Grande, Rockall, Sierra Leone, and other uplifts, and by the Kitovy, Newfoundland, and other ridges.

Seamounts (isolated conical elevations 1000 m or more high) on the bottom of the Atlantic Ocean are concentrated mainly in the zone of the Mid-Atlantic Ridge. In the deep waters, large groups of seamounts occur north of Bermuda, in the Gibraltar sector, off the northeast salient of South America, in the Gulf of Guinea, and west of South Africa.

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

Geological structure. The Atlantic Ocean arose as a result of the breakup of the Late Paleozoic supercontinent Pangea during the Jurassic. It is characterized by a sharp predominance of passive margins. The Atlantic Ocean borders the adjacent continents along transform faults south of Newfoundland, along the northern coast of the Gulf of Guinea, along the Falkland Submarine Plateau and the Agulhas Plateau in the southern part of the ocean. Active margins are observed in separate areas (in the area of ​​the Lesser Antilles arc and the arc of the South Sandwich Islands), where subduction with underthrust (subduction) of the Atlantic Ocean crust occurs. The Gibraltar subduction zone, limited in length, has been identified in the Gulf of Cadiz.

In the Mid-Atlantic Ridge, the bottom is being pushed apart (spreading) and oceanic crust is forming at a rate of up to 2 cm per year. High seismic and volcanic activity is characteristic. To 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 is pronounced rift valley , which is absent in the far south and most of the Reykjanes Range. Within its limits - volcanic uplifts, frozen lava lakes, basaltic lava flows in the form of pipes (pillow-basalts). In the Central Atlantic, fields of metal-bearing hydrotherms have been found, many of which form hydrothermal structures at the outlet (composed of sulfides, sulfates, and metal oxides); metal-bearing sediments have been established. At the foot of the slopes of the valley there are scree and landslides, consisting of blocks and crushed stone of oceanic crust rocks (basalts, gabbro, peridotites). The age of the crust within the Oligocene ridge is modern. The Mid-Atlantic Ridge separates the zones of the western and eastern abyssal plains, where the oceanic basement is covered by a sedimentary cover, the thickness of which increases towards the continental foothills up to 10-13 km due to the appearance of more ancient horizons in the section and the supply of detrital material from land. In the same direction, the age of the oceanic crust increases, reaching the Early Cretaceous (Middle Jurassic north of Florida). Abyssal plains are practically aseismic. The Mid-Atlantic Ridge is crossed by numerous transform faults extending to the adjacent abyssal plains. The thickening of such faults is observed in the equatorial zone (up to 12 per 1700 km). The largest transform faults (Vima, São Paulo, Romansh, etc.) are accompanied by deep incisions (troughs) on the ocean floor. They expose the entire section of the oceanic crust and partially 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 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 originated at the intersection of the spreading ridge by large transform faults. Volcanic uplifts include: Iceland Island, Bouvet Island, Madeira Island, Canary Islands, Cape Verde, Azores, paired uplifts of Sierra and Sierra Leone, Rio Grande and the Whale Range, Bermuda Uplift, Cameroon group of volcanoes, etc. In the Atlantic Ocean there are intra-plate uplifts of non-volcanic nature, among which is the underwater Rockall Plateau, separated from the British Isles by the trough of the same name. The plateau is a microcontinent that separated from Greenland in the Paleocene. Another micro-continent that also broke away 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) separated from the continents as a result of rifting in the late Jurassic - early Cretaceous.

The Atlantic Ocean is divided by transoceanic transform faults into segments with different opening times. From north to south, the Labrador-British, Newfoundland-Iberian, Central, Equatorial, Southern and Antarctic segments are distinguished. The opening of the Atlantic began in the Early Jurassic (about 200 million years ago) from the Central Segment. In the Triassic - Early Jurassic, the spreading of the ocean floor was preceded by continental rifting, traces of which are recorded in the form of semi-grabens (see Graben) filled with clastic deposits 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 the side axis, which continued until the late Eocene. Northern and South Atlantic united in the middle of the Cretaceous - Eocene during the formation of the Equatorial segment.

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

Climate. Due to the great length of the Atlantic Ocean, its waters are located in almost all natural climatic zones - from the subarctic in the north to the Antarctic in the south. From the north and south, the ocean is widely open to the influence of arctic and antarctic waters and ice. The lowest air temperature is observed in the polar regions. Over the coast of Greenland, temperatures can drop to -50°C, 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 successive change of stable large baric formations. Above the ice domes of Greenland and Antarctica - anticyclones, in the temperate latitudes of the Northern and Southern hemispheres (40-60 °) - cyclones, in lower latitudes - anticyclones, separated by a zone of low pressure at the equator. This baric structure maintains stable winds in tropical and equatorial latitudes. east direction(trade winds), in temperate latitudes - strong winds western direction, which received the name "roaring forties" from sailors. Strong winds are also characteristic of the Bay of Biscay. In the equatorial region, the interaction of the northern and southern baric systems leads to frequent tropical cyclones (tropical hurricanes), which are most active 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 greatest strength over the Caribbean Sea and the Gulf of Mexico. In areas of low pressure in temperate and equatorial latitudes, precipitation is frequent and heavy clouds are observed. Thus, at the equator over 2000 mm of precipitation falls annually, in temperate latitudes - 1000-1500 mm. In areas of high pressure (subtropics and tropics), the amount of precipitation decreases to 500-250 mm per year, and in areas adjacent to the desert coast of Africa, and in the South Atlantic High, to 100 mm or less per year. In areas where warm and cold currents meet, fogs are frequent, for example, in the area of ​​the Newfoundland bank and in La Plata Bay.

Hydrological regime. Rivers and water balance. In the Atlantic Ocean basin, 19,860 km 3 of water is annually carried out by rivers, which is more than in any other ocean (about 45% of the total flow into the World Ocean). The largest rivers (with an annual 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 fresh water balance of 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 deficit in the water balance is replenished by the inflow of water, mainly from the Pacific Ocean, through the Drake Strait with the course of the West Winds, 3470 thousand km 3 / year enters, and only 210 thousand km 3 / year goes from the Atlantic Ocean to the Pacific Ocean. From the Arctic Ocean, through numerous straits, 260 thousand km 3 / year enters the Atlantic Ocean and 225 thousand km 3 / year of Atlantic water flows back to the Arctic Ocean. Water balance with the Indian Ocean is negative, 4976 thousand km 3 / year is carried out into the Indian Ocean with the course of the West Winds, and only 1692 thousand km 3 / year comes back with the Coastal Antarctic Current, deep and bottom waters.

Temperature regime. The average temperature of the 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 asymmetric with respect 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 between 5 and 10 ° north latitude, that is, they are shifted north of the geographic equator. Features of large-scale circulation of waters lead to the fact that the temperature of water on the surface near the western coasts of the ocean is approximately 5 ° C higher than that of the eastern ones. The warmest water temperature (28-29 ° C) on the surface in the Caribbean Sea and the Gulf of Mexico in August, the lowest - off the coast of Greenland, Baffin Island, 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 bottom waters - 1.6 °C. At the very bottom, the water temperature rises slightly due to the 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 regions, where the evaporation of water from the surface exceeds its inflow with precipitation, the lowest (6-20‰) in the estuarine sections of large rivers flowing into the ocean. From the subtropics to high latitudes, salinity on the surface decreases to 32-33‰ under the influence of precipitation, ice, river and surface runoff. In temperate and tropical regions, the maximum salinity values ​​are on the surface, an intermediate minimum of salinity is observed at depths of 600-800 m. The waters of the northern part of the Atlantic Ocean are characterized by a deep salinity maximum (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 occupying the deepest depressions of the ocean, respectively, 34.7-34.8‰ and 1.6 °C.

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

Ice regime. In the northern part of the Atlantic Ocean, first-year ice forms mainly in the inland seas of temperate latitudes; multi-year ice is carried out of the Arctic Ocean. The boundary of the distribution of the 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. Antarctic border multi-year ice in winter it passes at a distance of 1600-1800 km from the coast (approximately 55 ° south latitude), in summer (in 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 the Antarctic glaciers is estimated at 1.6·10 12 tons per year, their main source is the Filchner Ice Shelf in the Weddell Sea. Icebergs with a total mass of 0.2-0.3 x 10 12 tons per year enter the Atlantic Ocean from the glaciers of the Arctic, mainly from the Jakobshavn glacier (near Disko Island off the western coast of Greenland). The average life expectancy of Arctic icebergs is about 4 years, Antarctic icebergs are somewhat longer. The iceberg distribution limit in the northern part of the ocean is 40° north latitude, but in some cases they have been observed up to 31° north latitude. In the southern part, the boundary passes at 40° S latitude in the central part of the ocean and at 35° S latitude on the western and eastern periphery.

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

Deep water circulation. The deep circulation and structure of the waters of the Atlantic Ocean are formed as a result of changes in their density during cooling of waters or in zones of mixing of waters of different origin, where density increases as a result of mixing of waters with different salinities and temperatures. 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. Deep waters are formed in the high latitudes of the northern and southern parts of the ocean. The waters formed in the Antarctic region have the highest density and spread from south to north in the bottom layer, their temperature is from negative (in high southern latitudes) to 2.5 ° C, salinity is 34.64-34.89‰. The waters formed in the high northern latitudes move from north to south in the layer from 1500 to 3500 m, the temperature of these waters is from 2.5 to 3 °C, salinity is 34.71-34.99‰. In the 1970s, V.N. Stepanov and, later, V.S. The broker substantiated the scheme of planetary interoceanic transfer of energy and matter, which was called the "global conveyor" or "global thermohaline circulation of the World Ocean". According to this theory, relatively salty North Atlantic waters reach the coast of Antarctica, mix with supercooled shelf water and, passing through the Indian Ocean, end their journey in the North Pacific Ocean.

Tides and excitement. The tides in the Atlantic Ocean are predominantly semidiurnal. Tidal wave height: 0.2-0.6 m in the open part of the 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) is the highest in the world. The height of wind waves depends on the speed, exposure time and wind acceleration, during strong storms it can reach 17-18 m. Quite rarely (once every 15-20 years) waves 22-26 m high were observed.

Flora and fauna. The great extent of the Atlantic Ocean, the diversity of climatic conditions, a significant inflow of fresh water and large upwellings provide a variety of habitat conditions. In total, about 200 thousand species of plants and animals live in the ocean (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 types of zonality in the distribution of life in the ocean: latitudinal or climatic, vertical and circumcontinental zonality. 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, most of them live in the upper zone of the ocean, where light penetrates. The highest plankton biomass is in high and temperate latitudes during the spring-summer bloom (1-4 g/m3). During the year, biomass can change by 10-100 times. The main types of phytoplankton are diatoms, zooplankton are copepods and euphausids (up to 90%), as well as chaetognaths, hydromedusae, ctenophores (in the north) and salps (in the south). At low latitudes, the plankton biomass varies from 0.001 g/m 3 in the centers of anticyclonic gyres to 0.3-0.5 g/m 3 in the Gulf of Mexico and Guinea. Phytoplankton is represented mainly by coccolithins and peridineans, the latter can develop in coastal waters in huge quantities, causing the catastrophic phenomenon of the "red tide". Low latitude zooplankton is represented by copepods, chaetognaths, hyperids, hydromedusae, siphonophores, and other species. There are no clearly pronounced dominant zooplankton species in low latitudes.

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

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

There is a 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, sailboats, various types of tuna and luminous anchovies; from animals - sea turtles, sperm whales, river dolphin inia; cephalopods are also numerous - various types of squids, octopuses, etc.

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

Research history

There are three stages in the study of the Atlantic Ocean. The first is characterized by the establishment of the boundaries of the ocean and the discovery of its individual objects. In the 12-5 centuries BC, the Phoenicians, Carthaginians, Greeks and Romans left descriptions of maritime wanderings and the first nautical charts. Their voyages reached the Iberian Peninsula, England and the mouth of the Elbe. In the 4th century BC, Pytheas (Pytheas), while sailing in the North Atlantic, determined the coordinates of a number of points and described the tidal phenomena in the Atlantic Ocean. Mentions of the Canary Islands date back to the 1st century AD. In the 9th-10th centuries, the Normans (Eirik Raudi and his son Leif Eirikson) crossed the ocean, visited Iceland, Greenland, Newfoundland and explored the coast of North America up to 40 ° north latitude. During the Age of Discovery (mid-15th - mid-17th century), navigators (mainly the Portuguese and Spaniards) mastered the route to India and China along the coast of Africa. The most outstanding voyages during this period were made by the Portuguese B. Dias (1487), the Genoese 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 for the first time 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. Buffin, 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 (the continent of Antarctica) were discovered and first described by the Russian Antarctic expedition of F. F. Bellingshausen and M. P. Lazarev in 1819-21. This completed the study of the boundaries of the ocean.

The second stage is characterized by the study of the physical properties of ocean waters, temperature, salinity, currents, etc. In 1749, the Englishman G. Ellis carried out the first temperature measurements at various depths, repeated by the Englishman J. Cook (1772), the Swiss O. Saussure (1780), Russian I.F. Kruzenshtern (1803) and others. In the 19th century, the Atlantic Ocean became a testing ground for testing new methods for studying depths, new techniques and new approaches to organizing work. For the first time, bathometers, deep-sea thermometers, thermal depth gauges, deep-sea trawls and dredges are used. Of the most significant, 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 "Seyklab" and "Arktika" under the leadership of M.F. Mori (1856-57). Real complex oceanographic research of the ocean began with an expedition on the English corvette "Challenger", led by C.W. Thomson (1872-76). The following significant expeditions were carried out on the ships Gazelle (1874-76), Vityaz (1886-89), Valdivia (1898-1899), Gauss (1901-03). A great contribution (1885-1922) to the study of the Atlantic Ocean was made by Prince Albert I of Monaco, who organized and led expeditionary research on the yachts Irendel, Princess Alice, Irendel II, Princess Alice II in the northern part of the ocean. In the same years he organized the Oceanographic Museum in Monaco. Since 1903, work began on the "standard" sections in the North Atlantic under the leadership of the International Council for the Study of the Sea (ICES), the first international oceanographic scientific organization 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, 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, the echo sounder 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, complex geophysical and geological studies of the Atlantic Ocean were carried out and the features of the topography of its bottom and tectonics, and the structure of the sedimentary strata were established. Many large forms bottom relief (submarine ridges, mountains, trenches, fault zones, vast basins and uplifts), geomorphological and tectonic maps were compiled.

The third stage of ocean research is mainly aimed at studying its role in the global processes of matter and energy transfer and its influence on climate formation. The complexity and wide range of research work required a wide range of international cooperation. The Scientific Committee for Oceanographic Research (SCOR), formed in 1957, the Intergovernmental Oceanographic Commission of UNESCO (IOC), which has been operating since 1960, and others play an important role in coordinating and organizing international research. international organizations. In 1957-58, a lot of work was carried out within the framework of the first International Geophysical Year (IGY). Subsequently, major 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 its study as part of the World Ocean (GEOSECS, 1973-74; WOCE, 1990-96, etc.). During the implementation of these projects, the features of the circulation of waters of various scales, the distribution and composition of suspended matter, the role of the ocean in the global carbon cycle, and many other issues were studied. In the late 1980s, Soviet deep-sea submersibles "Mir" explored the unique ecosystems of geothermal regions. rift zone ocean. If in the early 1980s there were about 20 international ocean research projects, then by the 21st century - over 100. The largest programs are: "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 world economy among other oceans of our planet. Human use of the Atlantic Ocean, as well as other seas and oceans, goes in several main areas: transport and communications, fishing, mining, energy, recreation.

Transport. For 5 centuries, the Atlantic Ocean has played a leading role in shipping. 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 per year was transported through its waters (according to IOC). About 1/2 of the volume of traffic is oil, gas and oil products, followed by general cargo, then iron ore, grain, coal, bauxite and alumina. The main direction of transportation is the North Atlantic, which runs between 35-40° north latitude and 55-60° north latitude. The main shipping routes connect the port cities of Europe, the USA (New York, Philadelphia) and Canada (Montreal). The sea routes of 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 directions of transportation are the South Atlantic: Europe - Central (Panama, etc.) and South America (Rio de Janeiro, Buenos Aires); East Atlantic: Europe - South Africa (Cape Town); West Atlantic: North America, South America - southern Africa. Prior to the reconstruction of the Suez Canal (1981), most of the oil tankers from the Indian Basin were forced to go around Africa.

Passenger transportation takes 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 would cross the ocean the fastest. This prize was awarded, for example, to such famous liners as Lusitania (4 days and 11 hours), Normandie (4 days and 3 hours), Queen Mary (4 days without 3 minutes). The last time the Blue Ribbon was awarded to the US liner United States was in 1952 (3 days and 10 hours). At the beginning of the 21st century, the duration of a passenger liner flight between London and New York is 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 traffic by air caught up with sea traffic, and then an increasing part of passengers prefer air transport (the record time for a flight of a supersonic liner "Concord" on the 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 - 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, almost the entire flow of passengers across the Atlantic Ocean is served by aviation.

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

Fishing. The Atlantic Ocean is considered the most productive ocean and its biological resources are most intensively exploited by man. In the Atlantic Ocean, fishing and seafood production account for 40-45% of the total world catch (an area of ​​about 25% of the World Ocean). Most of the catch (up to 70%) is made up of herring fish (herring, sardines, etc.), cod fish (cod, haddock, hake, whiting, saithe, saffron cod, etc.), flounder, halibut, sea bass. Production of shellfish (oysters, mussels, squids, etc.) and crustaceans (lobsters, crabs) is about 8%. According to FAO estimates, the annual catch of fish products in the Atlantic Ocean is 85-90 million tons, but for most of the fishing areas of the Atlantic, the fish catch reached its maximum in the mid-1990s and its increase is undesirable. The traditional and most productive fishing area is the northeastern part of the Atlantic Ocean, including the North and Baltic Seas (mainly herring, cod, flounder, sprats, mackerel). AT northwestern region ocean, on the Newfoundland banks, cod, herring, flounder, squid, etc. have been harvested for many centuries. In the central part of the Atlantic Ocean, sardines, horse mackerels, mackerels, tuna, etc. 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, catching sardines, anchovies and hake. In the Antarctic region of the ocean, planktonic crustaceans (krill), marine mammals, fish - notothenia, toothfish, silverfish, etc., are of commercial importance. Until the middle of the 20th century, in high-latitude northern and southern regions In the ocean, various species of pinnipeds and cetaceans were actively fished, but in recent decades it has declined sharply 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 developed more and more actively. Oil and combustible gas fields have been studied more fully, the first mention of their exploitation in the Atlantic Ocean basin dates back to 1917, when oil production began on an industrial scale in the eastern part of the Maracaibo lagoon (Venezuela). Major 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 (Orinok oil and gas basin), Brazilian shelf (Sergipe-Alagoas oil and gas basin), Gulf of Guinea (Gulf of Guinea oil and gas basin) ), the North Sea (North Sea oil and gas region), etc. Placer deposits of heavy minerals are common along many coasts. The largest development of alluvial deposits of ilmenite, monocyte, zircon, 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 Falkland Islands. On the shelf of southwestern Africa, the development of coastal marine diamond placers is underway. Gold-bearing placers were found off the coast of Nova Scotia at depths of 25-45 m. In the Atlantic Ocean, one of the world's largest iron ore deposits, Wabana, has been explored (in Conception Bay off the coast of Newfoundland), iron ore is also being mined off the coast of Finland, Norway and France. In the coastal waters of Great Britain and Canada, coal deposits are being developed, it is mined in mines located on land, the horizontal workings of which go under the seabed. Large sulfur deposits are being developed on the shelf of the Gulf of Mexico. In the coastal zone of the ocean, sand is mined for construction and glass production, gravel. Phosphorite-bearing sediments have been explored on the shelf of the east coast of the United States and the west coast of Africa, but their development is still unprofitable. 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 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 designed only for cruises have been laid down, they are distinguished by big sizes(displacement of 70 thousand tons or more), increased comfort level and relative low speed. The main routes of cruise liners are the Atlantic Ocean - the Mediterranean and Caribbean Seas and the Gulf of Mexico. Since the end of the 20th - the beginning of the 21st century, 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 Canaries, Azores, Bermuda, the Caribbean Sea and the Gulf of Mexico.

Energy. Energy sea ​​tides The Atlantic Ocean is estimated at about 250 million kilowatts. In the Middle Ages, tidal wave mills and sawmills were built in England and France. A tidal power plant operates at the mouth of the Rance River (France). The use of the hydrothermal energy of the ocean (temperature difference in surface and deep waters) is also considered promising; the 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 St. Nazaire, Copenhagen; in North America - New York, Houston, Philadelphia, Baltimore, Norfolk-Newport, Montreal, Boston, New Orleans; in South America - Maracaibo, Rio de Janeiro, Santos, Buenos Aires; in Africa - Dakar, Abijan, 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 XX century. M., 1978; Terms. Concepts, reference tables / Edited by S. G. Gorshkov. M., 1980; Atlantic Ocean. L., 1984; Biological resources of the Atlantic Ocean / Ed. editor D. E. Gershanovich. M., 1986; Broeker W.S. The great ocean conveyor // Oceanograpy. 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).

It occupies an area of ​​92 million km. It collects fresh water from the most significant part of the land and stands out among other oceans in that it connects both polar regions of the Earth in the form of a wide strait. The Mid-Atlantic Ridge runs through the center of the Atlantic. This is the belt of instability. Individual peaks of this ridge rise above the water in the form. Among them, the largest -.

The southern tropical part of the ocean is under the influence of the southeast trade wind. The sky above this part is slightly clouded with cumulus clouds that look like cotton wool. it the only place in the Atlantic, where there is no . The color of the water in this part of the ocean ranges from dark blue to bright green (near). The waters turn green when approaching, as well as near the southern shores. The tropical part of the South Atlantic is very rich in life: the density of plankton there is 16 thousand individuals per liter; there is an abundance of flying fish, sharks and other predatory fish. There are no builder corals in the southern part of the Atlantic: they have been pushed out of here. Many researchers notice that cold currents in this part of the ocean are richer in life than warm ones.

: 34-37.3‰.

Additional Information: the Atlantic Ocean got its name from the Atlas Mountains located in northwest Africa, according to another version - from the mythical continent Atlantis, according to thirds - on behalf of the titan Atlas (Atlanta); The Atlantic Ocean is conditionally divided into the Northern and Southern regions, the boundary between which runs along the equator line.

Secrets of the Atlantic Ocean

The Atlantic Ocean has been known to human civilization since time immemorial. It was here, according to ancient legends, that the mysterious island of Atlantis was located, which went under water seventeen thousand years ago. A warlike and courageous people (Atlanteans) lived on it, and the god Poseidon reigned over it together with his wife Kleito. The name of their eldest son was Atlan. In his honor, the boundless sea washing this land was named the Atlantic.

Atlantic Ocean

The mysterious civilization has sunk into oblivion, the sea was renamed the ocean, but the name has remained. The secrets of the Atlantic Ocean have not disappeared anywhere. As the centuries passed, there were no fewer of them. But before you get acquainted with everything unusual and mysterious, you need to get general idea about the majestic waters washing simultaneously the shores of hot Africa, and the lands of old Europe, and the distant rocky coast of the American continent, covered with a haze of fabulous legends.

Today, the Atlantic Ocean is called a huge body of water on planet Earth, which accounts for 25% of the volume of the oceans. 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 are 2.8 thousand km wide.

If we take the distance of 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 great difference. Its average value is 3600 m, and the maximum is recorded in the Puerto Rico trench and corresponds to 8742 meters.

The bottom of the Atlantic is divided lengthwise into two parts by the Mid-Atlantic Ridge. It exactly repeats the outlines of a huge body of water and stretches in a wide winding mountainous chain: from the north - from the Reykjanes Ridge (Iceland), to the African-Antarctic Ridge in the south (Bouve Island), going beyond the border of the distribution of Arctic ice.

Scattered to the right and left of the ridge are hollows, troughs, faults, small ridges that make the topography of the ocean floor very complex and confusing. The coastline (especially in northern latitudes) also has no simple structure. It is strongly indented by small bays, has vast water areas that go deep into the land and form seas. Numerous straits in the coastal zone of the continents, as well as straits and channels connecting the Atlantic with the Pacific Ocean, are also an integral part.

The Atlantic Ocean washes the shores of 96 state formations. It owns 14 seas and 4 large bays. The diverse climate in these geographical and geological parts of the earth's surface is provided by numerous surface currents. They flow full-flowing in all directions and are divided into warm and cold.

In the northern latitudes, up to the equator, the North Trade Wind, Gulf Stream and North Atlantic currents dominate. They carry warm waters and delight the world around them with a mild climate and high temperatures. This cannot be said about the Labrador and Canarian currents. The latter are cold and create frosty and slushy weather on the adjacent lands.

South of the equator, the picture is the same. The warm South Trade Wind, Guinean and Brazilian currents rule here. The cold West Winds and the Bengal wind try to be in no way inferior to their more humane counterparts and also make their feasible negative contribution to climate formation. 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 from the north and south the waters of the Atlantic are squeezed by eternal giant ice crusts. True, at the expense of eternity, a little bust, since often very large blocks of ice break off from them and begin to slowly drift towards the equator. Such blocks are called icebergs, and they move north of Greenland up to 40 ° N. latitude, and in the south of Antarctica to 40 ° S. sh. Their remnants are also observed closer to the equator, reaching 31-35 ° southern and northern latitudes.

Very large sizes is a loose concept. More specifically, there are icebergs that are tens of kilometers long and sometimes exceed 1,000 km² in area. These ice floes can travel through the expanses of 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 just over 100-120 meters.

Meeting with such sea ​​traveler for the courts has never been a joy. It poses the greatest danger already in adulthood. By this time, the iceberg has thawed significantly, its center of gravity has shifted, and the huge ice block has turned over. Its underwater part is above the water. It does not shine blue, but is a dark blue ice cap, which, especially in conditions of poor visibility, is very difficult to distinguish on the surface of the ocean.

The sinking of the Titanic

A typical example of the insidiousness of floating ice blocks can be the death 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: it is rather imprudent to write off everything on a "stray" iceberg. This shipwreck is still one of the greatest secrets Atlantic Ocean. There is still no clue to the causes of the tragedy, although there are a great many different Versky and assumptions.

As expected, the largest passenger ship in the world (length 269 m, width 28.2 m, displacement 46,300 tons) collided with an iceberg, which had a venerable age and apparently turned over in the water more than once. Its dark surface did not give reflections, it merged with the water surface of the ocean, so it was very difficult to notice a huge floating ice block in time. The culprit of the tragedy was recognized only when he was at a distance of 450 meters from the ship, and not 4-6 km, as usually happens in such situations.

The sinking of the Titanic made a lot of noise. It was a worldwide sensation at the beginning of the second decade of the twentieth century. Mostly everyone was amazed - how could such a huge and reliable ship sink so quickly, dragging hundreds and hundreds of unfortunate people to the bottom with it. Nowadays, many researchers tend to see the true causes of the terrible tragedy not in the ill-fated iceberg (although few people deny its indirect role), but in completely different factors that for some reason, at one time, were hidden from the general public.

Versions, conjectures, 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 part of the Titanic's hull like a tin can. The wound was terrible: its length reached 100 meters, and six of the sixteen waterproof compartments were damaged. This turned out to be enough for the proud Briton to go to the bottom and forever calm down at a huge depth, taking human lives and colossal material values ​​with him to the sea soil.

The sinking of the Titanic

The sinking of the Titanic

Such a verdict is not convincing for a specialist, and a person who is far from shipbuilding understands that the carrying hull of a huge liner plowing the oceans cannot in any way resemble a tin can. The melted ice of an old iceberg also does not have sufficient hardness, which, judging by the conclusion, should have exceeded the strength of a diamond in order to cut through the steel plating of a multi-ton passenger ship for tens of meters.

You can build various assumptions and hypotheses for an arbitrarily long time, but only practical research can answer all questions. In this situation, given the depth at which the Titanic lay, survey work became possible no earlier than the 80s of the XX century. It was at this time that deep-sea vehicles appeared capable of for a long time located at a depth of 4 km.

The first such swallow was the expedition of the American oceanologist Robert Ballard, who in September 1985 arrived at the scene of the tragedy on the ship Knor. She was armed with a deep-water towed complex "Argo". It was he who determined the depth of the remains of the Titanic. The water column in this place was 3,750 meters. The ship lay on seabed, split into two parts, the distance between them was approximately 600 meters.

No visible damage that caused the death of the ocean liner was found. Robert Ballard considered that they were hidden by the ground, in which the multi-ton structure was bogged down. A lacerated wound on the body of the Titanic was not found during the second expedition organized by an American scientist in 1986.

French and American experts followed the beaten track. In the summer of 1987, they arrived in the waters of the Atlantic Ocean and spent two long months at the crash site. Using the Nautil deep-sea submersible, the researchers recovered more than 900 items from the bottom of the sunken ship. These were samples of ship utensils, some of which ended up in museums, and some went to private collections.

Survey of the Titanic

A 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 and oceanographer Steve Blask. The expedition had at its disposal two autonomous underwater vehicles Mir-1 and Mir-2. On them, the researchers made 38 dives. The ship's hull was examined, a sample of the side plating was taken, film, video and photography were carried out.

Despite all efforts, a ragged hole, several tens of meters long, was not found. But it was possible to find a hole, the size of which did not exceed square meter, and numerous cracks were observed along the lines of the rivets.

A steel fragment that broke away from the Titanic's hull was sent for testing. It was checked for metal fragility - the conclusion was not encouraging: the prototype was amazingly fragile. This could be attributed to the long 80 years on the seabed, which significantly affected the properties of steel. Therefore, for the objectivity of the picture, a similar piece of metal was tested, which has been preserved at the shipyard since 1911. The result was almost the same.

It's hard to believe, but the body of the Titanic did not respond regulatory requirements. It was made from a material with a high content of sulfur compounds. The latter gave the steel structure a high brittleness, which, in combination with ice water, made it very brittle.

If the hull were made of steel that meets all the standards and requirements, then after contact with the iceberg, it would bend, but retain its integrity. In the same situation, the ship hit an iceberg with its starboard side - and the blow was of little force, but the fragile skin of the Titanic could not stand it either. It split along the rivet lines below the waterline. Ice water poured into the holes that formed, which instantly filled the lower compartments and, most likely, caused the explosion of red-hot steam boilers.

The huge ship began to rapidly sink into the waters of the Atlantic. According to eyewitnesses, at first the Titanic sank on an even keel, which indicates that the lower compartments were filled with water evenly. Then came the trim on the nose. The stern began to rise up, reached a vertical position, and the multi-ton colossus very quickly went to the bottom. Already at great depth, 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 catastrophe has nothing to do with the secrets 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 truth in last resort. 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 White Star Line company, the owner of the ship, was the culprit of the accident. 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 grand scam was to obtain a huge insurance policy that could correct the precarious financial situation of the company and save it from total collapse.

That is why the ocean liner, despite warnings about icebergs from ships in the same area, was moving at the highest possible speed (20.5 miles per hour). The task of the captain of the ship was one - 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 stake was placed on rescue ships, which should have had enough time to get to the scene of the tragedy and manage to save all passengers and valuables on board. However, unpredictable fate has made its own adjustments to the original scenario.

In addition to this rather dubious and unsteady version, there is another. It's a fire in a coal bunker. With prolonged storage, the lower layers of coal begin to smolder, releasing explosive gas. The temperature gradually increases, the concentration of gas vapors increases. In such a situation, an explosion can occur from a normal push. The collision with the iceberg was the detonator that caused a huge surge of energy that tore 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 a great depth can reveal this secret of the Atlantic Ocean. Their scrupulous study by dozens of specialists is possible only in 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 implement. As for financial side question, here is another picture. Although such work will cost crazy money, but they will more than pay off. After all, we must not forget that gold bars worth 10 million pounds sterling lie on the ship. Jewelry, diamonds, jewelry are also stored here. the richest people of the world that sailed on this ship. Fragments of the Titanic hull, the remains of the interior, dishes will leave the auctions with a bang at fabulous 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 great amount ships that are simply stuffed with precious metals, diamonds, and other valuables that can make anyone who gets to them rich. This is exactly the whole question: to break through the thickness of oceanic waters is an overwhelming task not only for individual adventurers, but also for serious firms and solid financial structures.

Underwater cemeteries of ships

At the beginning of the XXI century, there are many companies specializing in the search for sunken ships. The game is worth the candle, because according to experts, at least 80,000 ships of all countries and peoples that have been shipwrecked over the past 400 years, carrying valuables worth 600 billion dollars, are resting at the bottom of the Atlantic alone.

One of these companies - the American company "Odyssey" - discovered in 2007, in the area of ​​the Canary Islands, a Spanish sailing ship. On board were 500 thousand old 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 riches that were raised in 1985 from the 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 went to the bottom of the ocean in the 16th and in the first half of the 17th centuries rests precisely on Spanish ships, which in a continuous caravan carried to Europe from America the gold, silver, precious stones and products stolen from the Indian peoples.

In theory, the good obtained in this way cannot be the property of the state. The Spanish government thought otherwise. At the beginning of the 21st century, it declared 800 Spanish ships sunk in the 16th-18th centuries, carrying illegally acquired utensils, as a national treasure. The monetary equivalent of all this wealth is estimated at 130 billion dollars.

Underwater treasures are available for search teams in coastal zones Atlantic Ocean. Here, as a rule, ships sank, running aground or reefs. On 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 went to the bottom, having experienced all the power and strength of ocean storms (the height of the waves in the Atlantic often reaches 10-15 meters) or the cunning and cruelty of enemy pirate ships and submarines during the years of hostilities.

The ratio of ships drowned 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 coast, 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 visibility of native or foreign shores, which, as they say, were within easy reach.

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 it is 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, fogs are frequent. At the bottom of the strait rests countless ships, especially in its western part.

In terms of the number of shipwrecks, the waters in the area of ​​​​Cape Hatteras (North Carolina, USA) do not lag behind. There is a narrow long spit here, the eastern ledge of which is actually the ill-fated cape. This place is characterized by countless shoals, constant storms, fogs, strong currents. Vessels that dare to approach these shores expose themselves to a very real danger - the manifestation of carelessness, frivolity and ignoring the direction, almost constantly, leads to tragic consequences.

Bermuda Triangle

Perhaps the most intriguing mystery of the Atlantic Ocean can be called the Bermuda Triangle. Its peaks lie at 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 is also a part, located in Pacific waters around Miyake Island (Japan).

The excitement around this seemingly unremarkable place arose in the second half of the 20th century. Before, for hundreds of years, everything seemed to be normal. The ships sedately crossed this expanse of the ocean, and the crews on them did not even guess what mortal danger they were exposing themselves to.

The year 1950 put an end to such outrageous frivolity. It was then that a short article by Associated Press correspondent Edward Johnson came out. It was not even an article, but a thin pamphlet published in Florida in a small circulation. It was called the "Bermuda Triangle", and the facts presented in it told about the mysterious disappearances of ships and aircraft in the Bermuda region.

Bermuda Triangle

She did not attract the attention of the public in any way, but apparently forced the attention of individuals who feed on sensations and circulation of bestsellers to draw attention to themselves. However, it took almost 15 years before Vincent Gladdis's article titled "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 given to the mysterious part of the ocean.

A more detailed solid and capacious work was presented to the readers ten years later. The author of this bestseller, simply and concisely called "The Bermuda Triangle", was Charles Berlitz. It provided a lot of data on the mysterious disappearances of ships and aircraft, and also described incomprehensible phenomena associated with changes in the properties of time and space. Reputable publishing houses from 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 who do not feed with bread, but let them spoil a barrel of honey with a fly in the ointment. A blow to such a successfully and dynamically spreading sensation was dealt as early as the next 1975 by the American journalist Lawrence David Kouche. This gentleman did not leave a 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 crafty colleague, but a serious study based on a painstaking study of documents and eyewitness accounts. Precisely on the basis actual material many errors, inaccuracies, and sometimes outright hoaxes were revealed in the work of Charles Berlitz.

The conclusion of Lawrence David Couchet's book is unequivocal: nothing mysterious, supernatural, inexplicable happens in the Bermuda Triangle. The statistics of tragedies in this section of the Atlantic Ocean corresponds to similar data in any other place of the huge reservoir. The 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, it is necessary to provide iron evidence of this phenomenon. But in everyday life, things are not so simple. What lies beyond the real cannot be explained in terms of the laws of physics, mechanics or chemistry. Here, rather, the human imagination and faith in the mysterious and unusual dominate.

By the way, many paranormal activity, taking place in the Bermuda Triangle, can be interpreted as a direct consequence of the usual banal processes occurring in the waters of the Atlantic. For example, the mysterious disappearance of ships has a simple explanation related to methane emissions. This gas escapes from the gas hydrate deposits on the seabed and saturates the water. The density of the latter drops sharply. A ship that enters such a section of the ocean immediately sinks.

The released methane is not limited to the aquatic environment. It rises into the air and also reduces its density. This can lead to the death of aircraft, which is almost impossible to explain to people on the ground. We must not forget that the gas dissipates very quickly both in water and in air. That is, he is a killer, leaving no traces behind.

Anomalies over time can be explained by the increased activity of the magnetic field in the Bermuda Triangle zone. Passengers of the aircraft who find themselves in a bunch of magnetic forces can be convinced of their impact by looking at the hands of the wrist watch that have stopped or slowed down. After some time, the 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 opinion that the plane was lost in another dimension.

If we talk about ships found in the ocean, on which there was not a single crew member, then here the blame can be put on infrasound, which occurs on water surface under certain conditions. The human brain, heart, other organs of his body - they all have their own oscillation frequency. If some of them coincide with the frequency of infrasound, then the resulting resonance can ruthlessly hit the psyche of people, plunge them into horror and panic, make them jump overboard and die in the water.

All the arguments presented are quite convincing and realistic. But we must not forget that this is not evidence, but only assumptions. Supporters of the paranormal version can also put their vision of the problem to the public, which will be no less convincing and will find many adherents.

Where is the truth? Probably, as always, in the middle. sober look in combination with faith in the unusual and supernatural, it 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 material factruz