Outer and inner seas of the Atlantic Ocean. Where is the Atlantic Ocean? Ocean characteristics, North and South Atlantic oceans

The Atlantic Ocean occupying the second place among the world's oceans by area, was the first to attract the attention of researchers and for a long time remained the most studied. At present, geotectonic specialists tend to believe that the Atlantic Ocean is possibly the youngest.

There are subtle signs of the existence of a meridional water space in this part of the globe until the Late Mesozoic, that is, about 100 million years ago, and a connection between the South Atlantic and the Indian Ocean, as evidenced by organic remains of the Upper Cretaceous age. As a result of detailed and systematic studies of the northern and southern basins of the Atlantic Ocean conducted by the expedition on the Meteor, theories of the origin and structure of the Atlantic Ocean appeared. Cober (1928) was the first to suggest the existence of a system of mountain ranges encircling the globe, which he considered as an orogenic belt (as opposed to a taphrogenic Heezen's hypothesis).

According to the data of Cossin (1921), which are usually referred to, the area of ​​the Atlantic Ocean (the ocean itself) is about 8.2 * 10 ^ 7 km2, and including the marginal seas (Caribbean, Mediterranean, etc.) - about 10.6 * 10 ^ 7 km3. The average depth in the first case is 3920 m and in the second 3332 m.

The Atlantic Ocean is not as deep as the Pacific and Indian Oceans, mainly due to the vast continental shoals extending northward and the thick layer of sediment.

According to Murray (1888), the total area of ​​runoff into the Atlantic Ocean is about 3.5 10 ^ 7 km2, and including the Arctic, about 5.0 * 10 ^ 7 km2, which is four times the area of ​​runoff into the Indian Ocean and almost four times area of ​​drainage into the Pacific Ocean. At present, the water balance of the World Ocean can be maintained only with a constant flow from the Atlantic Ocean to other oceans.

In the Atlantic Ocean, unlike the Indian and Pacific Oceans, there are only a few seamounts and guyots and no coral atolls. Sections of the coastline are largely devoid of coastal reefs, even under favorable conditions. However, coral banks are known in the cold waters of the Atlantic Ocean.

The decrease in water temperature during the Pleistocene and the isolation of the Atlantic Ocean from latitudinal currents as a result of tectonic movements of the earth's crust in the Middle and Late Tertiary periods determined a rather poor and "isolated" benthic fauna, which contrasts with the "universal" nature of benthos in the Cretaceous and early Tertiary periods.

The main groups of islands of continental origin, they are located off the coast (Greenland, the Canadian Arctic Archipelago, Svalbard, Great Britain, the Falkland (Malvinas) Islands, the Scotia arc, etc.). Several oceanic islands cover only 5.0 * 106 km2 [Iceland (1.05.10 ^ 5 km2), Jan Mayen Island, Bermuda and Azores, Madeira Island, Canary Islands, Cape Verde Islands, Fernando de Noronha Island, Island Assension, St. Helena Island, Tristan da Cunha Island, Gough Island, Bouvet Island, etc. These islands are mainly of volcanic origin.

Basins of the atlantic ocean

Western atlantic

Labrodor Basin located between the Labrador Peninsula, Greenland and the island of Newfoundland. This basin extends well beyond the Labrador Sea and includes most of the Irminger Sea. Turbidity streams carrying sedimentary material settling on the bottom flow down the mid-oceanic canyon to the Som abyssal plain.

Newfoundland Basin located between the island of Newfoundland and the Azores. It is partially separated from the adjacent basins in the south. In the southwest, this basin is bounded by the Southeast Newfoundland Rise. Its northern border runs along a line from the Flemish Cap Bank in the northeast to the western branch of the Mid-Atlantnian Range, at about 55 ° N. sh., which from north to south crosses the mid-oceanic canyon connecting the Labrador depression with the abyssal plain of the Som.

North American Basin Is a very large depression, which, strictly speaking, is not a true basin. It is located near the underwater Bermuda Upland, as well as several abyssal plains that border the elevation on three sides — Som from the northeast, Hatteras from the west, and Nares (900 thousand km2) from the southeast. The last two plains are at 24 ° N. w, 68 ° W d. shares the Vema Abyssal Gorge. The Black Bahamas Outer Ridge separates the Hatteras Abyssal Plain from the narrow Black Bahamas Basin and Abyssal Plains. this basin includes the Puerto Rico Trench, a typical deep-sea trench in the Atlantic Ocean. There are two maximum depths within the trough, one of which is sometimes referred to as the Brownson Basin. the other was named the Milwaukee Basin (after the name of the ship that first discovered it), but even deeper depths were later discovered.

Guiana Basin located near the Venezuelan, Guiana and Amazonian coasts of Brazil. In the basin, the following are distinguished: in the west - the Demerara abyssal plain (335 thousand km2), on which sediments are accumulated carried out by the Orinoco River, the rivers of Guiana and partly by the Amazon runoff; in the east - the abyssal plain of Keara, separated from the abyssal by the early Demerara by the huge Amazonian abyssal cone, which is also its main source of sedimentary material.

Brazilian Basin (Tizard Basin) is located near the east coast of Brazil. It is bounded in the north by the Para Rise (now Belem), the continuation of which outside the basin is a partly volcanic ridge crowned with the islands of Fernando de Noronha and Rocas. At the northern end of the ridge there is a vast depression of the bottom - the Recife Abyssal Plain), however, to the south of the Trindade Volcanic Rise, the area of ​​the Abyssal Plain is small.

Argentine Basin. To the southwest of the Rio Grande seamount is the long narrow Argentine abyssal plain (200 thousand km2), to the east of it there is a wide, gently sloping Argentine uplift, an area of ​​insignificant abyssal hills.

Atlantco-Antarctic catlovin (South Atlantic Polar Basin; Afrnan-Antarctic Basin.) Stretching across the entire South Atlantic from the Weddell Sea to the Indian Ocean, includes the long depression, the Abyssal Weddell Plain. An isolated depression between South Sandwich and Bouvet Islands is the Sandwich Abyssal Plain. Here, another typical deep-sea trench of the Atlantic Ocean was discovered - the South Sandwich Trench (or Sandwich Trench) with a maximum depth of 8264 m. It is separated by several ridges from the Atlantic-Antarctic Basin. Within the Scotia Sea, there are numerous small closed basins that do not have names.

East atlantic

Western European Basin (Northeast Atlantic Basin). In the basin, two connecting abyssal plains were discovered: Porcupine to the west of Great Britain and Biscay (80 thousand km2), which in turn in the south by the abyssal Teta gorge (43 N abyssal plain. These abyssal plains are described by Lawton as part of a ledge-like system gradually descending southward along a series of narrow ravines and canals.

Iberian Basin (Spanish Basin) is located west of Spain (name
The Iberian Basin had another basin in the western Mediterranean, east of Spain; to avoid confusion, the latter was given the name "Balearic Basin") and is connected by the Teta Abyssal Gorge with the Biscay Abyssal Plain. The smaller depression, the Tajo Abyssal Plain (15 thousand km2), receives precipitation through the underwater canyon carried by the Tajo River (Portugal). In addition, to the south (west of the sources of sedimentary materials of Gibraltar, Guadiana and Guadalquivir) is the Horseshoe Abyssal Plain (14 thousand km2).

Canary basin (Monaco Basin) is located to the south of the Azores uplift (belt of seamounts), which stretches in the SEE direction. This basin is largely occupied by the Madeira Abyssal Plain and is now established to include a sector formerly part of the Canary Abyssal Plain. The smaller depression, the Sein Abyssal Plain (39 thousand km1), located east of the Seni Bank, is separated from this basin and, apparently, feeds from it. Wust distinguishes the North Canary and South Canary basins, but this distinction is not very clear. Most of the Canary Basin is the wide continental foot of Morocco and volcanic plateaus Canary Islands and Madeira Islands.

Cape Verde basin (North African Trench, Chan Basin, Moselle Basin). The Cape Verde Abyssal Plain is almost not separated from the Madeier Abyssal Plain (together 530 thousand km2, the border is a belt of abyssal hills), continues a vast belt of abyssal plains about 1000 km long, following along the outer border of West Africa, turns approximately to the west and southwest from the Cape Verde Islands. To the south of these islands lies the Gambia Abyssal Plain.

Sierra Leone Basin The above-mentioned belt of abyssal plains skirts the western coast of Africa, separated by aseismic uplift and abyssal hills from the Sierra Leone seamount, which in turn is separated from the mainland base by the Sierra Leone abyssal plain. At the same time, the width of the continental foot
decreases to about 500 km.

Guinean Basin (West African Trench). This basin is an extension of the same belt of abyssal plains in the Gulf of Guinea, but contains an elongated depression — the Abyssal Plain of Guinea, abundantly fed by the largest river in West Africa — the Niger, and the Niger abyssal fan.

Angolan Basin (Buchanan depression). South of the Guinean Volcanic Ridge (Fernando Po islands, etc.), there is an extensive depression of the Angola Abyssal Plain (140 thousand km Atlantic.

Cape Basin (Valvis Basin). The Whale Ridge, which runs from northeast to southwest parallel to the Guinea Ridge, but, in contrast to it, is currently aseismic and non-volcanic, is followed by the Cape Abyssal Plain, which is fed by the Orange River.

Agulhas Basin ... On a complex area of ​​the continental borderland (Bank of Agulhas) and a fault quasi-crate crust, the main depression is the Agulhas abyssal plain (east of latitude 20 ° located in the Indian Ocean).

Raised and ridges

The Mid-Atlantic Ridge is the main topographic feature of the Atlantic Ocean floor and divides the bulk of the ocean into two large basins. Secondary ridges or uplifts divide these basins into basins. However, the ridges rarely form a continuous chain, so that bottom waters from Antarctica can move north along the western edges of the Atlantic Ocean to the North American Basin and east and then south to the eastern basin through the Romanche Trench (or Romanche Gorge). The Romansh Trench corresponds to a large latitudinal fault zone. Another significant fault zone located to the north of the above is known as the Guinea Fault Zone. Another fault zone occurs at about 50-53 ° N. sh. This area, surveyed during the laying of the transatlantic cable, is called the Telegraph Plateau. The transverse ridges were mainly discovered and named by the Meteor expedition. The Atlantic Ocean has the following uplifts and ridges.

Western atlantic

Greenland-Icelandic uplift - a well-defined sill with a depth of less than 1000 m separates the Greenland Sea from the Irminger Sea.

Labrador uplift not distinctly expressed and extends from Flemish Bank towards the north-east. It is cut by a mid-oceanic canyon. It is believed that continental rocks are not found outside the bank.

Southeast Newfoundland Rise extends southeast of the Great Newfoundland Bank. Like the previous uplift, it is indistinct and is also cut by a mid-oceanic canyon.

Antillean or Caribbean arc (ridge) is a typical double island arc. The island of Barbados is an outer non-volcanic ridge. Numerous Windward Islands are of volcanic origin.

Raising Steam located between northeastern Brazil and the Mid-Atlantic Ridge and is not a barrier to deep currents. It is partly a "mound" of sedimentary materials coming from the underwater alluvial cones of the Amazon and others. To the southeast is a small volcanic ridge with mature, deeply dissected volcanic formations Fernando de Noronha and Rocas.

The Rise of Trindade - a distinct volcanic ridge, stretching to the east from the Brazilian province of Espiritu Saito for 1200 km. Reaches the highest altitude on Trindade Island and Martin Vas reefs. It partially forms the border between the North Brazilian and South Brazilian Basins, but east of
the island of Trindade has no barriers at all.

Rio Grande Seamount (sometimes called the Bromley Plateau) is a massive aseismic ridge that stretches east of the Brazilian province of Rio Grande do Sul for 1,500 km. It does not reach the edge of the Mid-Atlantic Ridge slightly. On the mainland side, it is partially separated from a wide plateau (continental borderland), located southeast of São Paulo, and consists of continental rocks, probably split from the shelf as a result of the Stock tectonics.

Falkland Plateau stretches 1800 km east of the Argentine shelf. Stille called it a structural spur of the borderland, composed of typical continental rocks (demonic and others, naked in the Falkland Islands). The plateau is partially split by faults going towards the Malvin Basin, south of the Falkland Islands.

Raising South Georgia - short, stretching northeast from South Georgia Island.

Arc, or ridge, Scotia (South Antilles arc, South Sandwich Ridge) is a typical island arc of non-volcanic origin, located in the area of ​​South Georgia and the South Orkney Islands, in the zone of volcanic activity near the angle of the maximum bend of the South Shetland Islands. It is assumed that latitudinal horizontal faults occur along the northern and southern edges of the arc, as in the Antilles arc in the Caribbean Sea. Thus, the two arcs are almost identical in structure.

East atlantic

Faroese Icelandic rapids an aseismic ridge that forms a massive barrier in the North Atlantic. The Faroe Islands are composed of mature clusters of volcanic origin. Volcanoes in this area have long lost their activity.

Wyville Thomson's threshold (Faroe - Shetland ridge) - an aseismic barrier similar to the Icelandic - Faroe ridge. It covers the Icelandic-Faroe Range in the south and adjoins it to the west of the Faroe Islands. In the south, the rapids are divided by a fault depression of the Faroe-Shetland Strait

Bank, or plateau, Rockall extends southwest of Wyville Thomson's Rapid and is surmounted by the Rockall isolated magma stock. It also belongs to aseismic
ridges.

Porcupine Bank is located near the continental shelf southwest of Ireland and is a wreck of the mainland borderland.

Biscay Rise extends west from Galicia (Spain) and essentially connects to the eastern edge of the Mid-Atlantic Ridge; it is crossed by a number of deep-water channels, along which turbidity streams move in a southerly direction.

Azores uplift extends east of the Azores Plateau, which is an unusual domed section of the Mid-Atlantic Ridge and resembles the young Icelandic Plateau. The uplift is a volcanic ridge formed by a continuous chain of seamounts. continuing to the Bank of the Seine and almost to the Strait of Gibraltar

Madeira ridge Is a short volcanic ridge located southwest of Portugal.

Raising the Canary Islands - a wide volcanic plateau, the geological structure of the basement of which is unknown, located parallel to the coast of North Africa and more like a continental borderland.

Cape Verde Plateau is a similar to the previous one, but a wider plateau (or uplift), classified by Hizen as an aseismic ridge, stretching to the west from the Senegalese coast of Africa for about 800 km. It is characterized by mature volcanoes as well as Tertiary rocks and is, at least in part, a continental borderland.

Sierra Leone upland - a weakly expressed uplift of abyssal hills, stretching southwest of Freetown and reaching the Mid-Atlantic Ridge northeast of Sao Paulo Island. It is crossed by several significant latitudinal fault zones, in particular the Guinea fault zone.

The Rise of Liberia - a small, but peculiar uplift of a mid-oceanic character, apparently dissected in the north and in the south by latitudinal faults. It partly separates the Sierra Leone Basin from the Guinea Basin.

Guinea ridge - a significant volcanic ridge, which is a continuation of the Cameroon volcanic belt. The Guinean Ridge passes through Fernando Po Island and other volcanic islands in the Gulf of Guinea Slightly south of the equator, it approaches the northeastern part of the Mid-Atlantic Ridge.

Whale ridge (Valvis) - the most significant cross ridge in the South Atlantic, connecting South-West Africa with the Srsdina-Atlantic ridge. It has benches of more than 1000 m, but at the southwestern end it drops significantly in the direction
Islands of Tristan da Cunha Islands of Gough.

Cape uplift - the southernmost transverse landform, partly a volcanic ridge, stretching from the Cape of Good Hope to the southwest towards Bouvet Island. It has a smoothed relief with separate seamounts.

Hydrological regime temperature and salinity

Of all the oceans in the world, the largest amount of data is available for the Atlantic Ocean. Compiled detailed maps of the temperature and salinity of the Atlantic Ocean.
There is also more data on chemical and biological characteristics in the Atlantic Ocean than in other oceans. It is also possible to calculate water and heat budgets, such as evaporation and heat transfer between the ocean and the atmosphere.

Temperature and salinity. The Atlantic Ocean is the warmest and saltiest of all oceans. It receives by far the largest part of the river flow. The average potential temperature and salinity are, respectively, 3.73 ° C and 34.90 prom. The temperature amplitude of the surface layer depends mainly on the latitude and the system of currents, its average value is 16 9 ° C (between 90 ° N and 80 ° S). The salinity of the surface layer is influenced by the amount of precipitation, the amount of fresh water flow from the continents and the presence of a current. Its average value is 34.87 prom (between 90 ° N and 80 ° S). Below the surface layer, the controlling factors for both parameters are advection and turbulent diffusion. There are seasonal variations in the temperature and salinity of the surface layer, extending to a depth of approximately 200 m. These changes are most pronounced near coasts with a continental climate.

The highest annual temperature amplitude of the surface layer in the open ocean is 7 ° C (between 40-50 ° N and 30-40 ° S). (This is the average zonal value; fluctuations in the Northwest Atlantic can reach 15 ° C.) The temperature amplitude of the surface layer in the equatorial and polar regions is less than 2 ° C. In coastal regions, the temperature of the surface layer can vary by 25 ° C throughout the year. the annual fluctuations in the salinity of the surface layer are influenced by various factors: melting and formation of sea ice (polar regions), seasonal changes in the rate of evaporation and the amount of precipitation (Caribbean Sea). In coastal areas affected by high spring runoff, such as near the northeastern coast of the United States, salinity fluctuations can be as high as 3 ppm; however, in the open ocean, the salinity of the surface layer changes to a much lesser extent, rarely by more than 1 ppm.

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 is in the inland seas. The area of ​​coastal seas is small and does not exceed 1% of the total area of ​​the 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 (the trench of Puerto Rico). The average annual salinity of ocean waters is about 35 ‰. The Atlantic Ocean has a highly indented coastline with a pronounced division into regional waters: seas and bays.

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

Specifications:

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

Etymology

The name of the ocean was first encountered in the 5th century BC. e. in the works 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 myth of Atlanta, a titan, well-known in Ancient Greece, holding on his shoulders the firmament at the extreme western point of the Mediterranean. The Roman scientist Pliny the Elder in the 1st century uses the modern name Oceanus Atlanticus (Latin Oceanus Atlanticus) - "Atlantic Ocean". V different time some 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 stretches from 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 along the shortest distance from South America to the Antarctic Peninsula through the Drake Passage, from Oste Island to Cape Sternek. The border with the Arctic Ocean runs along the eastern entrance of the Hudson Strait, then through the Davis Strait and along the coast of Greenland to Cape Brewster, through the Danish Strait to Cape Reidinupyur on the island of Iceland, along its coast to Cape Gerpier, then to the Faroe Islands, then to Shetland islands and 61 ° north latitude to the coast of the Scandinavian Peninsula. Sometimes the southern part of the ocean, with a northern boundary from 35 ° S. sh. (based on the circulation of water and atmosphere) up to 60 ° S. sh. (by the nature of the bottom relief), refer to Southern Ocean, which is not officially allocated.

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 major bays (clockwise): Irish Sea, Bristol Gulf, 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 ​​Azov, 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 St. Lawrence, Labrador Sea.

Islands

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

History of the formation of the ocean

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 present 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 junction of two large oceanic 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 at the expense of a reduction in the size of the Pacific Ocean. In the early Jurassic time, Gondwana began to split into Africa and South America and the oceanic lithosphere of the modern South Atlantic was formed. In the Cretaceous, Laurasia split, and the separation of North America from Europe began. At the same time, Greenland, shifting to the north, broke away from Scandinavia and Canada. Over the past 40 million years and up to the present, the opening of the Atlantic Ocean basin continues along a single rift axis located approximately in the middle of the ocean. Today movement tectonic plates continues. In the South Atlantic, the separation of the African and South American plates continues at a speed of 2.9-4 cm per year. In the Central Atlantic, the African, South American and North American plates are diverging at a speed of 2.6-2.9 cm per year. In the North Atlantic, the spread of the Eurasian and North American plates continues at a speed 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 region.

Geological structure and bottom topography

Submarine outskirts of continents

Significant areas of the shelf are confined to the northern hemisphere and adjoin the shores of North America and Europe. In Quaternary times, most of the shelf was subjected to continental glaciation, which formed relict glacial landforms. Another element of the relict topography of the shelf is flooded river valleys found in almost all shelf regions of the Atlantic Ocean. Relict 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). Sandy ridges are formed by tidal currents, which are the most widespread among modern subaquatic landforms. They are very characteristic of the North Sea shelf, and 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 by steep slopes, sometimes with a stepped profile and deeply dissected by submarine canyons. In some areas, the continental slopes are complemented by the marginal plateaus: Blake, Sao Paulo, Falklands on the American submarine margins; Bribe and Goban on the underwater outskirts of Europe. The blocky structure is the Farrero-Icelandic Rapid, which extends from Iceland to the North Sea. In the same region, there 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 folded by a thick (several kilometers) layer of bottom sediments. Three rivers of the Atlantic Ocean are among the ten largest in the world - Mississippi (solid flow 500 million tons per year), Amazon (499 million tons) and Orange (153 million tons). The total volume of sedimentary material carried out annually into the Atlantic Ocean basin by only its 22 main rivers is more than 1.8 billion tons. In some areas of the continental foot there are large cones of turbidity flows, among them the most significant are the fans of the underwater canyons of the Hudson, Amazon, and 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 in a southerly direction, giant accumulation forms of relief are formed (for example, the “sedimentary ridges” of Newfoundland, Blake-Bahamas, and others).

Transition zone

Transitional zones in the Atlantic Ocean are represented by areas: Caribbean, Mediterranean and the Scotia Sea or 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-Ciera-Maestra, Jamaica-South Haiti, outer and inner arcs of the Lesser Antilles. In addition, the seamount of Nicaragua, the Beata and Aves ranges are distinguished here. The Cuban Arc has complex structure and is of Laramian folding age. Its continuation is the northern cordelier of the island of Haiti. The folded structure of the Cayman-Sierra Maestra, which has a Miocene age, begins with the Mayan mountains on the Yucatan Peninsula, then continues in the form of the Cayman ridge and the Sierra Maestra mountain range of South Cuba. The Lesser Antilles arc includes a number of volcanic formations (including three volcanoes such as 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 Caribbean Andes mountain range, passing to the east into the islands of Trinidad and Tobago. Island arcs and underwater ridges divide the bottom Caribbean into several basins, which are leveled by a thick stratum of carbonate bottom sediments. The deepest of them is Venezuelan (5420 m). There are also two deep-water trenches here - Cayman and Puerto Rico (with the deepest Atlantic Ocean - 8742 m).

Areas of the Scotia Ridge and the South Sandwich Islands are borderlands - areas 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 is adjoined by the South Sandwich deep-water trench with a maximum depth of 8228 m. The mountainous and hilly relief of the Scotia Sea bottom is associated with the axial zone of one of the branches of the mid-ocean ridge.

The Mediterranean Sea has a widespread continental crust. The suboceanic crust is developed only in spots in the deepest basins: the Balearic, Tyrrhenian, Central and Cretan. The shelf is significantly developed only within 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 from the south, framed by the uplift of the East Mediterranean Wall. 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 (Vesuvius, Etna, Santorini) have survived here.

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 ridge. 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 latitude 52-53 ° N the mid-ocean ridge is crossed by the Gibbs and Reykjanes transverse fault zones. Behind them begins the Mid-Atlantic Ridge with a well-defined rift zone and rift valleys with numerous transverse faults and deep grabens. At a latitude of 40 ° N the mid-ocean ridge forms the Azores volcanic plateau, with numerous surface (forming islands) and underwater active volcanoes... To the south of the Azores plateau, in the rift zone, under calcareous silts with a thickness of 300 m, there are basalts, and beneath them is a blocky mixture of ultrabasic and basic rocks. The area is currently experiencing violent volcanic and hydrothermal activity. 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 Romanche depression is connected with deep-water faults with depths of up to 7856 m.

The South Atlantic Ridge has a meridional strike. Rift valleys are well defined here, the number of transverse faults is less, therefore this ridge looks more monolithic in comparison with the North Atlantic ridge. In the southern and middle parts of the ridge, there are volcanic plateaus 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 eastward, bends around Africa and in the Indian Ocean joins the West Indian Mid-Range Ridge.

Ocean bed

The Mid-Atlantic Ridge divides the Atlantic Ocean bed into two nearly equal parts. In the western part, mountain structures: the Newfoundland ridge, the Baracuda ridge, the Ceara and Rio Grande uplifts divide the ocean floor into depressions: Labrador, Newfoundland, North American, Guiana, Brazilian, Argentinean. 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 the basins: Western European, Iberian, North African, Cape Verde, Sierra Leone, Guinea, Angola, Cape. In the depressions, flat abyssal plains are widespread, composed mainly of calcareous biogenic and terrigenous material. Over most of the ocean floor area, the thickness of precipitation is more than 1 km. Under sedimentary rocks discovered a layer represented by volcanic rocks and compacted sedimentary rocks.

Abyssal hills are widespread along the periphery of mid-ocean ridges in areas of hollows remote from the underwater margins of the 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 underwater valleys, the most significant of which are the Hazen and Morey valleys in the northern Atlantic bed, stretching on either side of the Mid-Ocean Ridge.

Bottom sediments

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

Climate

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

All 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. To the north and south of the tropics, there are subtropical zones with more noticeable seasonal (from 10 ° C in winter to 20 ° C in summer) and daily temperature fluctuations; precipitation falls here mainly in summer. A frequent occurrence in the subtropical zone is tropical hurricanes. In these monstrous atmospheric vortices, the wind speed reaches several hundred kilometers per hour. The most powerful tropical hurricanes are in the Caribbean, such as the Gulf of Mexico and the West Indies. West Indian tropical hurricanes form in the western part of the ocean in the region of 10-15 ° N. and move to the Azores and Ireland. Further to the north and south are the subtropical zones, where in the coldest month the temperature drops to 10 ° C, and in winter cold air masses from the polar regions of low pressure bring abundant rainfall. In temperate latitudes, the average temperature of the warmest month is 10-15 ° C, and the coldest -10 ° C. Significant daily temperature drops are also noted here. The temperate zone is characterized by fairly even precipitation throughout the year (about 1,000 mm), reaching a maximum in 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 North and South circumpolar belts. In the Northern Hemisphere, this border runs in a wide strip between 50 ° N. (Labrador) and 70 ° N (coast of Northern Norway). In the Southern Hemisphere, the circumpolar zone begins closer to the equator - approximately 45-50 ° S. The most low temperature(-34 ° C) was 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 are, for example, the North Tradewind and South Tradewind currents crossing the ocean from east to west. The Northern Tradewind Current near the Lesser Antilles is divided: into a northern branch continuing to the northwest along the shores of the Greater Antilles (Antilles Current) and a southern branch extending through the straits of the Lesser Antilles into the Caribbean Sea, and then through the Yucatan Strait flows 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. The Gulf Stream, following along the American coast, at 40 ° N. as a result of the influence of westerly winds and the Coriolis force, it acquires an east and then a northeast direction and is called the North Atlantic Current. The main stream 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. From the North Arctic Ocean two powerful streams of cold freshened waters flow out - the East Greenland Current, passing along the eastern coast of Greenland, and the Labrador Current enveloping Labrador, Newfoundland and penetrating south to Cape Hatteras, pushing the Gulf Stream off the coast of North America.

The Southern Tradewind 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 to the north, forming the Guiana Current, which goes into the Caribbean Sea. The Brazilian Current in the La Plata region meets the cold Falkland Current (a branch of the Western Winds Current). Near the southern end of Africa, the cold Benguela Current branches off from the Western Winds 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-sea currents in the Atlantic Ocean. A powerful countercurrent passes under the Gulf Stream, the main rod of which lies at a depth of 3500 m, at 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. The Lomonosov subsurface current was discovered in the equatorial zone of the ocean. It starts from the Antilo-Guiana countercurrent and reaches the Gulf of Guinea. A 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 Atlantic Ocean has the highest tidal values, which are noted in the fiord 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 largest tide in the world is recorded in the Bay of Fundy, on the east coast of Canada, where the maximum tide is 15.6-18 m.

Temperature, salinity, ice formation

Fluctuations in the temperatures of Atlantic waters during the year are not great: in the equatorial-tropical zone - no more than 1-3 °, in the subtropics and temperate latitudes - within 5-8 °, in polar latitudes - about 4 ° in the north and no more than 1 ° on South. The warmest waters are in equatorial and tropical latitudes. For example, in the Gulf of Guinea, the surface temperature does not drop below 26 ° C. In the northern hemisphere to the north of the tropics, the temperature of the surface layer decreases (by 60 ° N it is 10 ° C in summer). In the southern hemisphere, temperatures rise much faster and by 60 ° S latitude. fluctuate 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, in the southern - the opposite.

The highest salinity of surface waters in the open ocean is observed in the subtropical zone (up to 37.25 ‰), and the maximum in the Mediterranean Sea is 39 ‰. In the equatorial zone, where the maximum amount of precipitation is noted, salinity decreases to 34 ‰. A sharp desalination of water occurs in the estuarine areas (for example, at the mouth of the 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 is present throughout the year up to 55 ° S, reaching its 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 in the Atlantic Ocean occurs, covering a surface layer with a thickness of 100 m in the southern hemisphere and up to 300 m in the tropics and equatorial latitudes. Below the surface water layer, outside the subantarctic zone, in the Atlantic there is Antarctic intermediate water, which is almost universally identified with an intermediate minimum salinity and is characterized by a higher content of nutrients in relation to the overlying waters, and extends northward to the region of 20 ° N latitude. 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 sinks to a depth of 1000 to 1250 m, passing into the deep water mass. In the southern hemisphere, this water mass drops to elevations of 2500-2750 m and wedges south of 45 ° S latitude. main feature of these waters - high salinity and temperature in relation to the surrounding waters. In the bottom layer of the Strait of Gibraltar, salinity is noted up to 38 ‰, temperatures are 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, drop 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, North Atlantic deep water is formed, which sinks as a result of winter cooling of relatively salty waters in the North European Basin and the Labrador Sea to a depth of 2500-3000 m in the northern hemisphere and up to 3500-4000 m in the southern hemisphere, reaching to about 50 ° S latitude. The North Atlantic deep water differs from the higher and lower Antarctic waters in higher salinity, temperature and oxygen content, as well as a lower content of nutrients.

Antarctic bottom water mass is formed on the Antarctic slope as a result of the mixing of cold and heavy Antarctic shelf water with lighter, warmer and saltier Circumpolar deep waters. These waters, spreading from the Weddell Sea, crossing 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 sublittoral zone - by kelp and alaria) and red algae. In the tropical zone, green (kaulerpa), red (calcareous lithotamnias) and brown algae (sargassum) predominate. In the southern hemisphere, benthic vegetation is mainly represented by kelp. The phytoplankton of the Atlantic Ocean has 245 species: peridinium, coccolithophorids, diatoms. The latter have a clearly pronounced zonal distribution; their maximum number lives in the temperate latitudes of the northern and southern hemispheres. The most densely populated diatoms are in the Western Winds Current.

The distribution of the fauna of the Atlantic Ocean has a pronounced zonal character. In 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 temperate zone, the biomass reaches a maximum. Zooplankton is dominated by copepods, pteropods; in the nekton, whales (blue whale), pinnipeds, and their fish are dominated by notothenia. 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 (squid), and among the benthal forms - octopuses. 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 relatively little species diversity. Of the commercial fish, the most important are herring, cod, haddock, halibut, and sea bass. Foraminifera and copepods are most typical for zooplankton. 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 sea cucumbers have been found in the Puerto Rican trench.

Ecological problems

Since time immemorial, the Atlantic Ocean has been a place of intensive marine fishing and animal hunting. The dramatic increase in capacity and the revolution in fishing technique have led to an alarming scale. With the invention of the harpoon cannon in the North Atlantic, whales were largely exterminated back in late XIX century. Due to 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 all types of commercial whaling. In June 2010, at the 62nd meeting of the International Whaling Commission, under pressure from Japan, Iceland and Denmark, the moratorium was suspended.

Explosion on oil platform Deepwater Horizon, owned by the British company BP, which occurred on April 20, 2010, is considered the largest environmental disaster that has ever occurred at sea. As a result of the accident, about 5 million barrels of crude oil spilled into the waters of the Gulf of Mexico, contaminating 1,100 miles of coastline. The authorities have 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 cetacean mortality in the north of the Gulf of Mexico was recorded several times compared to previous years (2002-2009).

In the Sargasso Sea, a large debris patch of plastic and other waste has formed, formed by ocean currents, gradually concentrating debris 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 is discharged into rivers and coastal waters of the seas, and sometimes into deep-sea parts of the ocean. The waters of the Atlantic Ocean heavily contaminated with radioactive waste include the North Sea, the Irish Sea, the Mediterranean Sea, the Gulf of Mexico, Biscay and the Atlantic coast of the United States. In 1977 alone, 7,180 containers with 5,650 tons of radioactive waste were dumped into the Atlantic. The US Environmental Protection Agency has reported a seabed contamination 120 miles east of the Maryland-Delaware border. Over the course of 30 years, 14,300 cemented containers were buried there, which contained plutonium and cesium, the radioactive contamination exceeded the "expected" by 3-70 times. In 1970, the United States sank the Russell Brigue, 500 kilometers off the coast of Florida, carrying 68 tons of nerve gas (sarin) in 418 concrete containers. In 1972, in the ocean waters north of the Azores, Germany flooded 2,500 metal barrels containing 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 disastrous consequences for the fauna and flora of the water areas. 4 nuclear submarines sank in the waters of the North Atlantic: 2 Soviet (in the Bay of Biscay and the open ocean) and 2 American (off the coast of the United States and in the open 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, the Russian Federation, Estonia, Latvia, Lithuania, Poland, Federal Republic of Germany, Denmark, Netherlands, Belgium, Great Britain, Ireland, Isle of Man (owned by Great Britain), Jersey (owned by Great Britain), France, Spain, Portugal, Gibraltar (owned by Great Britain), 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 of Northern Cyprus (not recognized by the UN), Akrotiri and Dhekelia (owned by Great Britain), Syria, Lebanon, Israel, 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, South Africa, Bouvet Island (owned by Norway), Saint Helena, Ascension and Tristan da Cunha (British possession);
• In South America (from south to north): Chile, Argentina, South Georgia and the South Sandwich Islands (owned by Great Britain), Falkland Islands (owned by Great Britain), Uruguay, Brazil, Suriname, Guyana, Venezuela, Colombia, Panama;
• In the Caribbean: American Virgin Islands (US possession), Anguilla (UK possession), Antigua and Barbuda, Bahamas, Barbados, British Virgin Islands (British possession), Haiti, Grenada, Dominica, Dominican Republic, Cayman Islands (British possession) , Cuba, Montserrat (UK), Navassa (US), Puerto Rico (US), Saint Vincent and the Grenadines, Saint Kitts and Nevis, Saint Lucia, Turks and Caicos (UK), Trinidad and Tobago , Jamaica;
• In North America: Costa Rica, Nicaragua, Honduras, Guatemala, Belize, Mexico, United States of America, Bermuda (British possession), Canada.

History of European exploration of the Atlantic Ocean

Long before the era of great geographical discoveries, numerous ships roamed the vastness of the Atlantic. As early as 4000 years BC, the peoples of Phenicia were engaged in maritime trade with the inhabitants of the Mediterranean islands. 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 the British Isles. By the 6th century BC, Ancient Greece, possessing a huge military merchant fleet at that time, sailed to the shores of England and Scandinavia, in the Baltic Sea and to the west coast of Africa. In the X-XI Art. The Vikings added a new page to the exploration of the North Atlantic Ocean. According to most researchers of the pre-Columbian discoveries, the Scandinavian Vikings were the first and more than once to swim across the ocean, 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 of the Caribbean islands and the vast continent later called America. In 1497, Vasco da Gama passed from Europe to India, circling Africa from the south. In 1520, Fernand Magellan, during his first circumnavigation of the world, passed 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 intensified so much that the Vatican was forced to intervene in the conflict. In 1494, an agreement was signed, which 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 the colonial riches were being developed, the waves of the Atlantic began to regularly surf the ships carrying gold, silver, precious stones, pepper, cocoa and sugar to Europe. Arms, textiles, alcohol, food and slaves for cotton and sugarcane plantations were delivered to America in the same way. It is not surprising that in the XVI-XVII Art. pirate fishing and privateering flourished in these parts, and many famous pirates such as John Hawkins, Francis Drake and Henry Morgan wrote their names in history. The southern border of the Atlantic Ocean (mainland 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 off the coast of Denmark, and serious scientific research was initiated in 1803-1806 by the first Russian round the world expedition under the command of naval officer Ivan Kruzenshtern. Temperature measurements at various depths were carried out by J. Cook (1772), O. Saussure (1780), and others. Participants in subsequent trips measured the temperature and specific gravity of water at different depths, took samples of water transparency and established the presence of underwater currents. Collected material made it possible to compile a map of the Gulf Stream (B. Franklin, 1770), a map of the depths of the North Atlantic Ocean (MF Mori, 1854), as well as maps of winds and ocean currents (MF Mori, 1849-1860) and other studies ...

From 1872 to 1876, the first scientific oceanic expedition took place on the English sailing-steam corvette Challenger, new data were obtained on the composition of ocean waters, flora and fauna, bottom topography and soils, the first map of the ocean depths 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-screw corvette Vityaz (1886-1889), on the German ships Valdivia (1898-1899) and Gauss (1901-1903) and others. The largest works were carried out on the English ship Discovery II (from 1931), thanks to which oceanographic and hydrobiological studies were carried out in the open part of the South Atlantic at great depths. In the framework of the International Geophysical Year (1957-1958), international forces (especially the United States and the USSR) carried out studies, as a result of which new bathymetric and marine navigational charts of the Atlantic Ocean were compiled. In 1963-1964, the Intergovernmental Oceanographic Commission conducted a large 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), USA, Brazil and others country.

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

Economic significance

Fishing and marine industries

The Atlantic Ocean provides 2/5 of the world's 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 the temperate latitudes of the northern hemisphere - herring, cod, haddock, halibut, sea bass. In the 1970s, due to overfishing of some fish species, the volume of fishery decreased sharply, but after the introduction of strict limits, fish stocks are gradually recovering. In the Atlantic Ocean basin, several international conventions on fisheries are in force, aiming at the efficient and rational use of biological resources, based on the application of scientifically based measures to regulate fishing.

Transport routes

The Atlantic Ocean occupies a leading position in the world's shipping. Most of paths leads from Europe to North America. The main navigable straits of the Atlantic Ocean: Bosphorus and Dardanelles, Gibraltar, English Channel, Pas-de-Calais, Baltic straits (Skagerrak, Kattegat, Øresund, Big and Small 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, and also to the Indian Ocean by the artificial Suez Canal through the Mediterranean Sea. Largest ports: St. Petersburg (general cargo, oil products, metals, timber cargo, 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), Filixstow, Valencia, Algeciras, Barcelona, ​​Marseille (oil, ore, grain, metals, chemical cargo, sugar , fruits and vegetables, wine), Joya 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: machines, fertilizers, cast iron, building 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 (groundnuts, 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, industrial goods), Santos , Rio de Janeiro (export: iron ore, cast iron, coffee, cotton, sugar, cocoa beans, lumber, meat, wool, leather, import: oil products, equipment, coal, grain, cement, food), Houston (oil , grain, sulfur, equipment), New Orleans (ores, coal, construction materials, cars, grain, rolling, equipment, coffee, fruits, food), Savannah, New York (general cargo, oil, chemical cargo, equipment, cellulose , paper, coffee, sugar, metals), Montreal (grain, oil, cement, coal, timber, metals, paper, asbestos tons, weapons, fish, wheat, equipment, cotton, wool).

Leading role in passenger traffic between Europe and North America air traffic across the Atlantic Ocean. Most of the transatlantic lines run in the North Atlantic through Iceland and Newfoundland. Another connection 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 to Rio de Janeiro. Airlines from the United States to Africa pass through the Bahamas, Dakar and Robertsport. On the shores of the Atlantic Ocean there are cosmodromes: Cape Canaveral (USA), Kourou (French Guiana), Alcantara (Brazil).

Minerals

Extraction of minerals, 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. Natural gas is also produced on the shelf of the North Sea. In the Gulf of Mexico, industrial production of sulfur is carried out, and off the island of Newfoundland - iron ore. Diamonds are mined from placers on the South African continental shelf. 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 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 highly diverse. The main countries of formation of outbound tourism in this region are formed in Europe (Germany, Great Britain, France, Italy, Netherlands, Belgium, Austria, Sweden, 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, 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 (as of 2010 by 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 shallowest sea in the world. The average depth is only 7.4 m, the greatest is 13.5 m. The sea was formed approximately in 5600 BC. after the spill of the neighboring Black Sea, which flooded the mouth of the Don, forming a new water area.

The Sea of ​​Azov is probably the only one in the world that has had more than 100 names in its entire history! Here are just some of them: Meoti, Karguluk, Balysyra, Samakush, Saksin, Frank, Kaffskoe, Akdeniz. The modern name of the sea was given by the city of the same name, conquered for Russia by Peter I. And only from the middle of the 18th century on the maps it began to be designated as Azov.

Despite its shallow depth, the Sea of ​​Azov is considered one of the richest in terms of the number of individuals per 1 sq. Km. According to this indicator, it is 40 times richer than the Mediterranean and 160 times richer than the Black.

- marginal sea in the north-west of Europe. The area is 415 thousand square kilometers, the average depth is 51 m. Some scientists distinguish part of the sea between the Gulfs of Bothnia and Finland as a separate water area - the Archipelago Sea.

In the "Tale of Bygone Years" this sea is called Varangian, the Swedes, Germans and Danes called it the Eastern, and in ancient Rome the sea was described as the Sarmatian Ocean. For a long time, the Baltic Sea was considered one of the main transport routes connecting Russia and Europe.
The Hebrides Sea is located between Scotland and the Hebrides. Area - 47 thousand sq. Km, average depth - 64 m.

The sea is cold, winds and hurricanes often rage over its surface, alternating with showers and fogs. The weather is unpredictable here, which makes navigation very difficult.

- a small sea (area 100 thousand square kilometers) between Great Britain and Ireland. The ancient Greeks called it the Ibernian Ocean. In winter storms rage here, in summer the water warms up to 13-16 ° C. And the height of the tidal waves reaches 6 meters.

Over the past 100 years, the issue of building a bridge over the sea or an underwater tunnel has been widely discussed. And according to Greenpeace, the Irish Sea is considered the most radioactively contaminated in the world.

Divides Central and South America, and through the Panama Canal is connected with the Pacific Ocean. Its area is 2.7 million square kilometers, the average depth is 2500 m.

The sea got its name in honor of the Caribbean - a group of Indian tribes who settled in the Antilles in the 15th century, that is, at the time when the Spanish conquerors appeared in these waters. However, very often this sea was called the Antilles.

In the 17th and 18th centuries, piracy flourished in the Caribbean, which had a significant impact on the development of the region's economy. The most famous pirates of the Caribbean: Henry Morgan, Edward Teach (nicknamed "Blackbeard") and Bartholomew Roberts ("Black Brother").

By the way, Tortuga is a real island in the Caribbean, which was once a stronghold of piracy.

Washes the southern parts of Ireland and Great Britain and the northwestern coast of France.

The name for the sea in 1921 was proposed by the English scientist E. Holt, who decided to perpetuate the memory the most ancient people who lived in this region - the Celts. Until that time, the northern part of the sea was considered part of the St George's Strait, and the southern part was designated as the "southwestern approaches" to Great Britain. After a number of studies at the beginning of the 20th century, it was decided to single out this water area as a separate sea and assign it an official name.

Washes the southeastern coast of Greenland. This small area is famous for its harsh climate and cold waters brought here by the Arctic currents. The sea is named after the greatest Danish hydrographer of the 19th century K.L. Irminger.

- the northernmost sea of ​​the Atlantic with an area of ​​840 thousand square kilometers, the average depth is 1898 m. The proximity of the Arctic is clearly felt here. V winter months The Labrador Sea is 2/3 covered by floating ice. And because of the melting of glaciers, icebergs are often found. One of the largest turbidite channels in the world lies in this water area.

Despite the harsh climate, the coasts of Labrador were inhabited as early as the 5th century BC. The coast of this sea has become home to many ancient cultures of the Indians and Eskimos.

The sea is named after the island of the same name, which was discovered by the Portuguese G. Cortirial in 1500. Translated from the port. Terro do Lavrador means the land of the plowman.

- the inland sea dividing the Asian and European part Turkey. Area - 11.4 thousand sq. Km, average depth - 259 m.

The Sea of ​​Marmara was formed several million years ago; its description is found in the historical works of the ancient Greeks and Arabs. But the first scientific research was carried out here by the Russians: in 1845 - the expedition of M.P. Manganari, in 1890 - a special scientific expedition of S.O. Makarov and I. B. Shpindler.

- a unique sea that is in many ways different from all the seas on earth.

Firstly, it is the only sea on the planet without a coast. Its boundaries are currents. That is why the area of ​​the Sargasso Sea is determined approximately - 6-7 million square kilometers.

Secondly, the sea is included in the Guinness Book of Records as the largest stretch of calm water. Indeed, almost 90% of the sea is covered with sargassum - brown algae. Such a vast spot can be seen even from space.

Thirdly, this is one of the safest seas in the world, since predatory marine animals do not look here for fear of getting entangled in algae. Other fish (especially eels) use this with might and main, choosing these seas for laying eggs.

Until recently, the waters of the Sargasso Sea were considered the most transparent - there is little plankton, so you could look almost 60 meters deep. Unfortunately, currents bring here a lot of garbage, including plastic waste, which seriously threaten the ecology of the water area.

Washes north coast Europe, located between British Isles, Scandinavia and the mainland. Area - 755 thousand sq. Km, average depth - 95 m.

The North Sea is of great transport importance. Almost all the main sea routes of our planet intersect here, and the cargo turnover in this sea is 20% of the world.