To me these two oceans seem complete opposite. One has very cold waters, the other, on the contrary, is the warmest of the oceans. But do they have any common features? I think that these two oceans should be disassembled.

Features of the concept of "ocean"

It is one of the largest geographic water bodies. The totality of all the oceans makes up the so-called World Ocean. It is located among all the continents and is characterized by a system of water circulation. Each of the four oceans can be distinguished by its own characteristics. Quiet, for example, the most huge. The Arctic is the coldest and smallest among all. The Atlantic is characterized by its cold currents and is the dividing line between Europe and America. Indian is the warmest of all. By the way, the ocean is the main source of various chemical elements, and all of them are constantly renewed.

Description of the Indian Ocean

Geographically, the ocean is located between:

• Africa (west);
• Eurasia (north);
• Antarctica (south);
• Australia (east).

It is connected with the Atlantic and Pacific Oceans. The Indian Ocean is located in both the Northern and Southern Hemispheres and, at the same time, is located entirely in the eastern part of the planet. The area of ​​the ocean is 76 thousand square kilometers. The main seas that belong to the ocean: Arabian, Red, Timor, Andaman. The deepest point is located in the Sunda Trench (7729 meters). The average depth is 3.9 km.

Atlantic Ocean

The ocean washes with its waters:

• Eurasia;
• South America;
• Antarctica;
• North America;
• Africa.

It has a direct connection with the Arctic Ocean (north), Indian (east), Pacific (west). Like Indian, covers both hemispheres. For the most part, its territory dominates the western part of the world. The area of ​​the Atlantic Ocean is larger, namely, 92 million km². The following seas belong to this ocean: Mediterranean, North, Baltic, Azov, Aegean, Black. The deepest point is 8.7 km, and the average depth does not exceed 3.7 km.

Atlantic Ocean part of the World Ocean, bounded by Europe and Africa from the east and North and South America from the west. The name comes from the name of the titan Atlas (Atlanta) in Greek mythology.

Atlantic Ocean inferior in size only to the Pacific; its area is approximately 91.56 million km 2. The length of the Atlantic Ocean from north to south is about 15,000 km, and its minimum width is about 2,830 km (in the equatorial part of the Atlantic Ocean). The average depth is 3332 m, the average volume of water is 337541 thousand km 3 (without seas, respectively: 82441.5 thousand km 2, 3926 m and 323 613 thousand km 3). 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.

States of the Atlantic coast - 49 countries: Angola, Antigua and Barbuda, Argentina, Bahamas, Barbados, Benin, Brazil, Great Britain, Venezuela, Gabon, Haiti, Guyana, Gambia, Ghana, Guinea, Guinea-Bissau, Grenada, Democratic Republic Congo, Dominica, Dominican Republic, Ireland, Iceland, Spain, Cape Verde, Cameroon, Canada, Cote d'Ivoire, Cuba, Liberia, Mauritania, Morocco, Namibia, Nigeria, Norway, Portugal, Republic of the Congo, Sao Tome and Principe , Senegal, Saint Kitts and Nevis, Saint Lucia, Suriname, USA, Sierra Leone, Togo, Trinidad and Tobago, Uruguay, France, Equatorial Guinea, South Africa.

Climate

The climate of the Atlantic Ocean is varied; the predominant part of the ocean area is between 40 degrees N. sh. and 40 degrees south. sh. located in the equatorial, tropical and subtropical climate zones. In the north and south of the ocean, areas of strong cooling and high atmospheric pressure are formed. The circulation of the atmosphere over the ocean causes the action of the trade winds, in temperate latitudes - westerly winds, which often turn into storms. Climate features are reflected in the properties of water masses.

It is conditionally carried out 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 border is usually drawn along the Northern 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 narrow northern part is connected to the Arctic Ocean by three narrow straits. In the northeast, the Davis Strait, 360 km wide, connects it with the Baffin Sea, belonging 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 tropical zone in the southwest of the North Atlantic are the Caribbean Sea and Gulf of Mexico connected to the ocean by the Strait of Florida. Coast North America 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.

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 Strait of Florida and the island of Cuba in a northerly direction along the coast of the United States and at about 40 ° N. latitude. 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. 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 southern border Atlantic is an imaginary line connecting Cape Horn in South America with the Cape 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. The southernmost tip of this continent - Tierra del Fuego - has a rugged coastline bordered by numerous small islands.

major islands not 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, South Atlantic two main underwater mountain ranges stand out. 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 protrusion of the east coast of Brazil, it divides 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 the 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.

currents of the atlantic ocean

Between the currents of the Atlantic Ocean, one should distinguish between permanent and surface. The latter are completely flat, shallow, purely surface currents, arising wherever a continuous, not too weak wind blows. These currents are therefore for the most part very variable; however, the current, supported on both sides of the equator by the trade winds, is quite even and reaches a speed of 15-18 km per day. But even constant currents, especially if they are weaker, with respect to direction and strength, are subject to the influence of continuous winds. Between constant currents, it differs primarily equatorial a current that crosses the A. ocean in its entire width from east to west. It begins approx. near the Guinean Islands and has an initial width of 300-350 km between 1 ° north. lat. and 2 - 2 S ° south. lat. In the west, it gradually widens, so that on the meridian of Cape Palma it extends already between 2° N. lat. (even further north) and 5 ° south. wide, and approx. 10° west duty. reaches a width of 8° - 9° (800-900 km). A little to the west of the Ferro meridian, a rather significant branch separates from the main current in a northwestern direction, traced up to 20 °, in some places up to 30 ° north. lat. The equatorial current itself near the Brazilian coast in front of Cape San Roque is divided into the Guiana current (north) and the Brazilian coastal current (south). The initial speed of this current is 40-50 km per day, to Yu.Z. from Cape Palma in summer sometimes increases to 80-120 km, and even further west, approx. at 10° west latitude, it reaches an average of 60 km again, but can rise up to 110 km. The temperature of the equatorial current is everywhere several degrees lower than the temperature of the neighboring parts of the sea, and thus proves that the water of this current is supplied by polar currents. Challenger's research showed that the equatorial current does not reach a significant depth either, since already at a depth of 100 m the current speed was found to be half that on the surface, and at 150 m depth there was almost no movement at all. South branch - brazilian current, stretches approx. at a distance of 400 km from the coast, has a daily speed of 35 km and, gradually expanding, reaches the mouth of La Plata. Here it divides: the weaker branch continues south almost to Cape Gorn, while the main branch turns east and joins with the current from the Pacific Ocean, which goes around the southern tip of America, to form the great South Atlantic current. This latter accumulates its waters off the southern part of the western coast of Africa, so that only with a southerly wind the Agulhas current, which goes around the southern tip of the mainland, delivers its more warm waters to the north, while in the case of western or northern winds it turns completely to the east. Off the coast of Lower Guiana, the northern current dominates, carrying the accumulated waters back into the equatorial current. The northern branch of this current called Guiana- goes along the coast of South America at a distance of 20 km from it, strengthened on the one hand by the northern trade wind current, on the other hand, by the waters of the Amazon River, forming a current towards the north and northwest. The speed of the Guiana Current ranges from 36 to 160 km per day. Between Trinidad and Martinique, it enters the Caribbean Sea, which it crosses with gradually decreasing speed in a large arc, generally parallel to the coast, until it flows through the Yucatan Strait into the Gulf of Mexico. Here it divides into two branches: the weaker one along the northern coast of the island of Cuba goes straight to the Strait of Florida, while the main branch describes a large arc parallel to the coast and at southern tip Florida connects with the first branch. The speed gradually increases to 50-100 km per day. Through the Florida Strait (Beminin Gorge), it again enters open ocean entitled gulfstrom, dominating under the northern part of the A. ocean; the significance of the Gulfstrom extends far beyond the limits of the A. ocean; he rendered greatest influence on the whole development of the newest international relations (cf. Gulfstrom). Crossing A. ocean approx. at 40° north lat., it is divided into several branches: one goes between Iceland and the Faroe Islands to the northeast; the other has an easterly direction, enters the Bay of Biscay at Cape Ortegala and then makes a turn to the north and northwest. called the Rennel current, separating a small side branch into the Irish Sea, meanwhile the main current with reduced speed goes to northern shores Norway and is even noticed near our Murmansk coast. The current of the Rennel is dangerous for sailors, as it often drives ships heading to the Pas de Calais to the cliffs of the Scillian Islands. outstanding value for navigation and climate, they also have two currents emerging from the Arctic Ocean: one of them (East Greenland) is directed along the eastern coast of Greenland to the south, maintaining this direction for the bulk of its waters up to 50 ° north. lat., separating only a branch that runs past Cape Farewell into Davis Strait; the second current, often incorrectly called the Hudson Bay Current, leaves Baffin Bay through Davis Strait and joins the East Greenland Current at New Foundland. Encountering an obstacle there in the Gulfstrom, this current turns to the west and runs along the coast of the United States to Cape Hatteras and is noticeable even near Florida. Part of the waters of this current apparently passes under the Gulfstrom. Since the water of this current is 10 ° sometimes even 17 ° colder than the Gulfstrom, it has a strong cooling effect on the climate of the eastern coast of America. Shipping should especially keep this current in mind because of the mass of ice it brings from the polar countries. These ice floes take the form of either ice mountains originating from the Greenland glaciers, or ice fields torn off from ice jams Arctic Ocean. In the area of ​​the North Atlantic shipping lines, these floating ice masses appear in March and threaten ships sailing there until August.

Flora and fauna of the Atlantic Ocean

Flora The Atlantic Ocean is very diverse. Bottom vegetation (phytobenthos), which occupies the coastal zone to a depth of 100 m (about 2% of the total area of ​​the ocean floor), includes brown, green and red algae, as well as flowering plants living in salt water (philospadix, zoster, poseidonia).
There are similarities between the bottom vegetation of the northern and southern parts of the Atlantic Ocean, but the leading forms are represented by different species and sometimes even genera. The similarity between the vegetation of the western and eastern coasts is more clearly expressed.
There is a clear geographical change in the main forms of phytobenthos in latitude. In the high arctic latitudes of the Atlantic Ocean, where the surface is covered with ice for a long time, the littoral is devoid of vegetation. The main mass of phytobenthos in the sublittoral is kelp with an admixture of red algae. The temperate zone along the American and European coasts of the North Atlantic is characterized by the rapid development of phytobenthos. The littoral is dominated by brown algae (fucus and ascophyllum). In the sublittoral, they are replaced by species of kelp, alaria, desmarestia, and red algae (furcelaria, anfeltia, lithotamnion, rhodimenia, etc.). Zostera is common on soft soils. In the temperate and cold zones of the Southern Hemisphere, brown algae, in particular kelp, predominate. In the tropical zone in the littoral and in the upper horizons of the sublittoral, due to strong heating and intense insolation, vegetation is almost absent.
Between 20 and 40° N. sh. and 30 and 60°W in the Atlantic Ocean is located the so-called. Sargasso Sea, characterized by the constant presence of a mass of floating brown algae - Sargasso.
Phytoplankton, unlike phytobenthos, develops over the entire area of ​​the ocean in the upper 100-meter layer, but reaches its highest concentration in the upper 40-50-meter layer.
Phytoplankton is made up of small unicellular algae(diatoms, peridine, blue-green, flint-flagellated, coccoliths). The mass of phytoplankton ranges from 1 to 100 mg/m 3 , and in high latitudes (50-60°) of the Northern and Southern hemispheres during the period of mass development (“flowering”) it reaches 10 g/m 3 or more.
In the cold and temperate zones The northern and southern parts of the Atlantic Ocean are dominated by diatoms, which make up the bulk of phytoplankton. The coastal regions of the North Atlantic are characterized by the mass development of pheocistis (from golden algae) in spring. Widespread in the tropics different kinds coccolithin and the blue-green alga Trichodesmium.
The greatest quantitative development of phytoplankton in the high latitudes of the Atlantic Ocean is observed in summer during the period of the most intense insolation. The temperate region is characterized by two peaks in the development of phytoplankton. Spring "flowering" is characterized by maximum biomass. During autumn "flowering" biomass is much lower than in spring. In the tropical region, phytoplankton development occurs all year round, but the biomass throughout the year is low.
The flora of the tropical region of the Atlantic Ocean is characterized by greater qualitative diversity, but less quantitative development than the flora of the temperate and cold zones.

Animal organisms inhabit the entire water column of the Atlantic Ocean. The diversity of fauna increases towards the tropics. In cold and temperate zones, it has thousands of species, in tropical - tens of thousands. The cold and temperate zones are characterized by: from mammals - whales and pinnipeds, from fish - herring, cod, perch and flounder, in zooplankton there is a sharp predominance of copepods and sometimes pteropods. There is a great similarity between the faunas of the temperate zones of both hemispheres. At least 100 species of animals are bipolar, that is, they are characteristic of cold and temperate zones and are absent in the tropics. These include seals, seals, whales, sprats, sardines, anchovies, and many invertebrates, including mussels. For tropical belts The Atlantic Ocean is characterized by: sperm whales, sea turtles, crustaceans, sharks, flying fish, crabs, coral polyps, scyphoid jellyfish, siphonophores, radiolarians. The fauna of the Sargasso Sea is peculiar. Both free-swimming animals (mackerel, flying fish, sea needle, crabs, etc.) and animals attached to algae (anemones, bryozoans) live here.
Deep-sea fauna The Atlantic Ocean is richly represented by sponges, corals, echinoderms, crustaceans, fish, and others. This fauna stands out as an independent Atlantic deep-sea region. For commercial fish, see Fisheries and Marine Fishing.

Seas and bays

Most of seas Atlantic Ocean in terms of physical and geographical conditions, they are Mediterranean - the Baltic, Black, Mediterranean, Caribbean Seas, the Gulf of Mexico, etc., and marginal - the North, the Gulf of Guinea.

Islands

The largest islands are concentrated in the northern part of the ocean; these are the British Isles, Iceland, Newfoundland, Cuba, Haiti (Hispaniola) and Puerto Rico. On the eastern edge of the Atlantic Ocean there are several groups of small islands - 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. Along the convex side of the arc are located deep sea trenches.

There are no large islands in the South Atlantic Ocean, but 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.

It is its great length (16 thousand km) from north to south - from the Arctic to the Antarctic latitudes and a relatively small width, especially in equatorial latitudes, where it does not exceed 2900 km. The average depth of the ocean is 3597 m, the maximum is 8742 m (Puerto Rico Trench). It was the Atlantic Ocean with the peculiarities of its configuration, age and bottom topography that served as the basis for the development of the theory of continental drift - the theory of mobilism - movement lithospheric plates. It was formed as a result of the split of Pangea, and then the separation of Laurasia and Gondwana. The main processes of the formation of the Atlantic took place in the Cretaceous period. The axial zone of the ocean is the “S”-shaped Mid-Atlantic Ridge, which rises above the bottom of the basin by an average of 2000 m, and in Iceland, taking into account its above-water part, by more than 4000 m. The Mid-Atlantic Ridge is young, tectonic processes it is active to this day, as evidenced by earthquakes, surface and underwater volcanism.

Unlike other oceans, the Atlantic has significant areas continental crust(off the coast of Scotland, Greenland, the Blake Plateau, at the mouth of La Plata), which indicates the youth of the ocean.

In the Atlantic, as in other oceans, planetary morphostructures are distinguished: the underwater margins of the continents (shelf, continental slope and continental foot), transition zones, mid-ocean ridges and the ocean floor with a series of basins.

The characteristic features of the Atlantic Ocean shelf are the presence of its two types (glacial and normal) and the unequal width off the coasts of North and South America, Europe and Africa.

The glacial shelf is confined to the areas of development of modern and cover Quaternary glaciation, it is well developed in the northern part of the Atlantic, including the North and Baltic Seas, and off the coast of Antarctica. The glacial shelf is characterized by great dissection, wide development of glacial exaration and accumulative relief. South of Newfoundland and Nova Scotia on the American side and the English Channel on the European side, the glacial shelf is replaced by a normal one. The surface of such a shelf is leveled by accumulative-abrasive processes, which from the beginning of the Quaternary period to the present have influenced the bottom topography.

The African shelf is very narrow. Its depths are from 110 to 190 m. In the south (near Cape Town) it is terraced. The shelf of South America is narrow, with depths up to 90 m, leveled, gently sloping. In some places there are terraces and weakly expressed underwater valleys of large rivers.

The continental slope of the normal shelf is leveled, passing towards the ocean either as a series of terraces with inclinations of 1–2°, or as a steep ledge with inclinations of 10–15°, for example, near the Florida and Yucatan peninsulas.

From Trinidad to the mouth of the Amazon, this is a dissected ledge with depths up to 3500 m with two ledges: the Guiana and Amazon marginal plateaus. To the south, the ledge is stepped with blocky forms. Off the coast of Uruguay and Argentina, the slope has a concave shape and is heavily dissected by canyons. The continental slope off the coast of Africa is of a blocky nature with well-defined steps near the Cape Verde Islands and the delta of the river. Niger.

Transitional zones are areas of articulation of lithospheric plates with underthrust (subduction). They occupy a small place in the Atlantic Ocean.

One of these zones - a relic of the Tethys Ocean - is located in the Caribbean-Antilles and continues into the Mediterranean Sea. It is separated by the expanding Atlantic. In the west, the role of the marginal sea is played by the Caribbean Sea, the Greater and Lesser Antilles Islands form island arcs, they are accompanied by deep-sea trenches - Puerto Rico (8742 m) and Cayman (7090 m). In the south of the ocean, the Scotia Sea borders the South Antilles submarine ridge with chains from the east volcanic islands forming an arc (South Georgia, South Sandwich, etc.). At the eastern foot of the ridge there is a deep-water trench - Yuzhno-Sandvichev (8264 m).

The mid-ocean ridge is the brightest geographical feature Atlantic Ocean.

The northernmost link of the Mid-Atlantic Ridge itself - the Reykjanes Ridge - at 58 ° N. sh. bounded by the sublatitudinal Gibbs Fault Zone. The ridge has a distinct rift zone and flanks. At o. The Iceland crest of the ridge has steep ledges, and the Gibbs Fault is a double chain of trenches with structures offset up to 350 km.

District about. Iceland, the surface part of the North Atlantic Ridge, is a very active rift structure passing through the entire island, with spreading, as evidenced by the basalt composition of the entire ridge shaft, the youth of sedimentary rocks, the symmetry of anomalous magnetic lines, an increased heat flow from the bowels, the presence of numerous small earthquakes, breaks in structures (transform faults), etc.

On a physical map, the pattern of the Mid-Atlantic Ridge can be traced along the islands: Fr. Iceland, on east slope- Azores, at the equator - about. St. Paul, southeast - about. Ascension, further on. Saint Helena, Fr. Tristan da Cunha (between and Cape Town) and about. Bouvet. Having rounded Africa, the Mid-Atlantic Ridge joins with the ranges.

The northern part of the Mid-Atlantic Ridge (to the Azores) has a width of 1100-1400 km and represents an arc convex to the east.

This arc is cut by transverse faults - Faraday (49° N), Maxwell (48° N), Humboldt (42° N), Kurchatov (41° N). The flanks of the ridge are gently sloping surfaces with block-block-ridge relief. North-east of the Azores - two ridges (Poliser and Mesyatseva). The Azores Plateau is located at the site of a triple junction of plates (oceanic and two continental). The southern part of the North Atlantic Ridge up to the equator also has the form of an arc, but its convex part is turned to the west. The width of the ridge here is 1600-1800 km, narrowing to 900 km towards the equator. The entire length of the rift zone and flanks is dissected by transform faults in the form of troughs, some of which also extend into the adjacent basins of the ocean floor. The most well-studied are the Okeanograph, Atlantis, and Romany transform faults (at the equator). The displacement of structures in the faults is within 50-550 km with a depth of up to 4500 m, and in the Romansh trench - 7855 m.

South Atlantic Ridge from the equator to about. Bouvet is up to 900 km wide. Here, as well as in the North Atlantic, the rift zone is developed with depths of 3500-4500 m.

Faults of the southern part - Cheyne, Ascension, Rio Grande, Falkland. On the eastern flank, on the underwater plateaus, the mountains of Bagration, Kutuzov, and Bonaparte rise.

In the Antarctic waters, the African-Antarctic Ridge is not wide - only 750 km, dissected by a series of transform faults.

A characteristic feature of the Atlantic is a fairly clear symmetry of the orographic structures of the bed. On both sides of the Mid-Atlantic Ridge there are basins with a flat bottom, successively replacing each other from north to south. They are separated by small underwater ridges, rapids, uplifts (for example, Rio Grande, Kitovy), successively replacing each other from north to south.

In the extreme northwest is the Labrador Basin, more than 4,000 m deep - a flat abyssal plain with a thick two-kilometer sedimentary cover. Next - Newfoundland Basin ( maximum depth more than 5000 m), with an asymmetric bottom structure: in the west it is a flat abyssal plain, in the east it is hilly.

The North American Basin is the largest in size. In the center is the Bermuda Plateau with a thick layer of precipitation (up to 2 km). Drilling revealed Cretaceous deposits, but geophysical data indicate that there is an even older formation under them. Volcanic mountains form the base of the Bermuda Islands. The islands themselves are composed of coral limestone and represent a giant atoll, which is rare for the Atlantic Ocean.

To the south is the Guyana Basin, part of which is occupied by the threshold of Para. It can be assumed that the threshold has an accumulative origin and is associated with the accumulation of material from turbidity flows fed by the huge removal of solid sediments from the Amazon (more than 1 billion tons per year).

Further south is the Brazil Basin with a range of seamounts, one of which is home to the only coral atoll in the South Atlantic, Rocas.

The largest basin in the South Atlantic - the African-Antarctic - from the Scotia Sea to the Kerguelen Rise, its length is 3500 miles, its width is about 800 miles, and its maximum depth is 6972 m.

In the eastern part of the ocean floor there is also a series of basins, often separated by volcanic uplifts: in the region of the Azores, near the Cape Verde Islands and the Cameroon Fault. The basins of the eastern part (Iberian, Western European, Canary, Angolan, Cape) are characterized by the oceanic type of the earth's crust. The sedimentary cover of the Jurassic and Cretaceous age has a thickness of 1-2 km.

Ridges play an important role in the ocean as ecological barriers. The basins differ from each other in bottom sediments, soils, and a complex of minerals.

Bottom sediments

Among the bottom sediments of the Atlantic, the most common are foraminiferal silts, occupying about 65% of the area of ​​the ocean floor, in second place are deep-sea red and red-brown clays (about 20%). Terrigenous deposits are widespread in the basins. The latter are especially characteristic of the Guinean and Argentine basins.

Bottom sediments and bedrock of the ocean floor contain wide range mineral. The Atlantic Ocean is rich in oil and gas fields.

The most famous deposits of the Gulf of Mexico, North Sea, the Bay of Biscay and the Bay of Guinea, the Maracaibo lagoon, coastal regions near the Falkland (Malvinas) Islands. New fields and gas are discovered annually: off the east coast of the United States, in the Caribbean and North Seas, etc. By 1980, 500 fields were discovered on the shelf off the coast of the United States, and more than 100 in the North Sea. drilling. In the Gulf of Mexico, for example, the Glomar Challenger drilled and discovered a salt dome at a depth of 4000 m, and off the coast of Iceland in an area with sea depths from 180 to 1100 m and a thick four-kilometer sediment cover, an oil-bearing well was drilled with a flow rate of 100-400 tons per day.

In coastal waters with powerful ancient and modern alluvium, there are deposits of gold, tin, and diamonds. Monazite sands are mined off the coast of Brazil. This is the world's largest deposit. Ilmenite and rutile deposits are known off the coast of Florida (USA). Most large placers ferromanganese nodules and phosphorite deposits belong to the regions of the South Atlantic.

Features of the climate of the Atlantic Ocean

The climate of the Atlantic Ocean is largely determined by its large meridional extent, the features of the formation of the baric field, and the peculiarity of the configuration (water areas are larger in temperate latitudes than in equatorial-tropical ones). On the northern and southern margins there are huge regions of cooling and the formation of high atmospheric pockets. Above the ocean area, constant areas of low pressure are also formed in equatorial and temperate latitudes and high blood pressure- in the subtropics.

These are the Equatorial and Antarctic depressions, the Icelandic low, the North Atlantic (Azores) and South Atlantic highs. The position of these centers of action changes with the seasons: they shift towards the summer hemisphere.

Trade winds blow from the subtropical highs to the equator. The stability of the direction of these winds is up to 80% per year, the strength of the winds is more variable - from 1 to 7 points. In the temperate latitudes of both hemispheres, westerly winds dominate, with significant speeds, in the Southern Hemisphere often turning into a storm - the so-called "roaring forties" latitudes.

Atmospheric pressure distribution and features air masses affect the nature of cloudiness, the regime and amount of precipitation. Cloudiness over the ocean varies by zone: the maximum amount of clouds near the equator with a predominance of cumulus and cumulonimbus forms, the least cloudiness - in tropical and subtropical latitudes, in temperate latitudes the number of clouds increases again - stratified and stratified-nimbus forms dominate here.

Dense fogs are very characteristic of the temperate latitudes of both hemispheres (especially the Northern), formed when warm air masses and cold waters of the ocean come into contact, as well as when waters of cold and warm currents meet at about. Newfoundland. Especially dense summer fogs in this area complicate navigation, especially since icebergs are often found there. In tropical latitudes, fogs are most likely near the Cape Verde Islands, where the dust carried from the Sahara serves as condensation nuclei for atmospheric water vapor. Fogs are also common off the southwestern coast of Africa in the region of the climate of "wet" or "cold" deserts.

Highly dangerous phenomenon in the tropical latitudes of the ocean - tropical cyclones, causing hurricane-force winds and heavy showers. Tropical cyclones often develop from small depressions that move from the African continent to the Atlantic Ocean. Gaining strength, they become especially dangerous for the islands of the West Indies and southern North America.

Temperature regime

On the surface, the Atlantic Ocean is generally colder than the Indian Ocean due to its large north-south extent, small width near the equator, and wide connection with.

Medium surface water- 16.9°С (according to other sources - 16.53°С), while in the Pacific - 19.1°С, Indian - 17°С. The average temperature of the entire thickness also differs. water mass Northern and Southern hemispheres. Mainly due to the Gulf Stream, the average water temperature of the North Atlantic (6.3°C) is somewhat higher than that of the South (5.6°C).

Seasonal temperature changes are also well observed. The lowest temperature is recorded in the north and in the south of the ocean, and the highest - vice versa. However, the annual temperature amplitude at the equator is no more than 3°С, in subtropical and temperate latitudes - 5-8°С, in subpolar latitudes - about 4°С. Daily fluctuations in the temperature of the surface layer are even less - on average 0.4-0.5°C.

The horizontal temperature gradient of the surface layer is significant at the meeting points of cold and warm currents, such as the East Greenland and Irminger, where a temperature difference of 7°C over a distance of 20-30 km is a common occurrence.

Annual temperature fluctuations are clearly seen in the surface layer up to 300-400 m.

Salinity

The Atlantic Ocean is the saltiest of all. The salt content in the waters of the Atlantic is on average 35.4% o, which is more than in other oceans.

The highest salinity is observed in tropical latitudes (according to Gembel) - 37.9% o, in the North Atlantic between 20 and 30 ° C N.S. sh., in the South - between 20 and 25 ° S. sh. The trade wind circulation dominates here, there is little precipitation, while evaporation makes up a layer of 3 m. Fresh water from land almost does not come. Somewhat higher medium salinity and in the temperate latitudes of the Northern Hemisphere, where the waters of the North Atlantic Current rush. Salinity in equatorial latitudes - 35% o. There is a change in salinity with depth: at a depth of 100-200 m it is 35.4% o, which is associated with the subsurface Lomonosov current. It has been established that the salinity of the surface layer in some cases does not coincide with the salinity at depth.

Sharp drops in salt content are also observed when currents of different temperatures meet. For example, south of Newfoundland at the meeting of the Gulf Stream and the Labrador Current on insignificant distance salinity drops from 35% o to 31-32% o.

The existence in the Atlantic Ocean of underground fresh water - submarine sources (according to I. S. Zetzker) - is an interesting feature of it. One of them has long been known to sailors, it is located east of the Florida Peninsula, where ships replenish their supplies. fresh water. This is a 90-meter "fresh window" in the salty ocean. Here a typical phenomenon of unloading of an underground source occurs in the area of ​​tectonic disturbances or areas of karst development. When the pressure groundwater exceeds column pressure sea ​​water, unloading occurs - the outpouring of groundwater to the surface. A well was recently drilled on the continental slope of the Gulf of Mexico off the coast of Florida. When drilling a well, a column of fresh water 9 meters high escaped from a depth of 250 m. The search and study of submarine sources is just beginning.

Optical properties of water

Transparency, which determines the illumination of the bottom, the nature of the heating of the surface layer, is the main indicator optical properties. It varies over a wide range, which is why the albedo of water also changes.

The transparency of the Sargasso Sea is 67 m, the Mediterranean - 50, the Black - 25, the North and Baltic - 13-18 m. The transparency of the waters of the ocean itself is far from the coast, in the tropics it is 65 m. The optical structure of the waters of the tropical latitudes of the Atlantic is especially interesting. The waters here are characterized by a three-layer structure: the upper mixed layer, a layer of reduced transparency and deep transparent ones. Depending on the hydrological conditions, the thickness, intensity, and a number of features of these layers vary in time and space. The depth of the layer of maximum transparency decreases from 100 m off the coast North Africa up to 20 meters off the coast of South America. This is due to the turbidity of the waters at the mouth of the Amazon. The waters of the central part of the ocean are homogeneous and transparent. The structure of transparency is also changing in the upwelling zone off the coast of South Africa due to the increased content of plankton. The boundaries between layers with different transparency are often blurry and fuzzy. Against the mouth of the river The Congo also has a three-layer profile, to the north and south - a two-layer one. In the Guinean sector of the Atlantic, the picture is the same as at the mouth of the Amazon: many particulate matter rivers carry out into the ocean, in particular the river. Congo. Here is the place of convergence and divergence of currents, deep transparent waters rise along the continental slope.

Water dynamics

They learned about the existence in the ocean relatively recently, even the Gulf Stream became known only at the beginning of the 16th century.

There are currents in the Atlantic Ocean various origins: drift - North and South Trade winds, West drift or West Winds (with a flow rate of 200 sverdrups), stock (Florida), tidal. In the Bay of Fundy, for example, the tide reaches record levels (up to 18 meters). There are also density countercurrents (for example, the Lomonosov countercurrent is subsurface).

Powerful surface currents in the tropical latitudes of the ocean they are caused by the trade winds. These are the North and South Tradewinds, moving from east to west. At the eastern shores of both Americas, they branch out. In summer, the Equatorial countercurrent manifests itself most effectively, its axis moves from 3° to 8° N. sh. The North Tradewind current near the Antilles is divided into branches. One goes to the Caribbean Sea and the Gulf of Mexico, the other - the Antilles branch merges with the Florida branch and, leaving the bay, forms a giant warm Gulf Stream. This current, together with its branches, has a length of more than 10 thousand km, the maximum flow is 90 sverdrups, the minimum is 60, the average is 69. The water flow in the Gulf Stream is 1.5-2 times greater than that of the largest currents of the Pacific and Indian Oceans - Kuroshio and Somali. The width of the stream is 75-100 km, the depth is up to 1000 m, the speed is up to 10 km/h. The boundary of the Gulf Stream is determined by an isotherm of 15°C at a depth of 200 m. Salinity is more than 35% o, in the southern branch - 35.1% o. The main stream reaches 55°W. e. Prior to this segment, there is almost no transformation of the water mass on the surface; at a depth of 100-300 m, the properties of the flow do not change at all. At Cape Hatteras (Gateras), the waters of the Gulf Stream divide into a series of narrow, strongly meandering streams. One of them, with an expenditure of about 50 Sverdrups, goes to the Newfoundland Bank. From 41°W The North Atlantic Current begins. Rings are observed in it - vortices moving in the direction of the general movement of water.

The North Atlantic Current also "branches", the Portuguese branch separates from it, which merges with the Canary Current. In the north, the Norwegian branch is formed and further - the North Cape. The Irminger Current departs to the northwest, meeting with the cold runoff East Greenland Current. West Greenland in the south merges with the Labrador current, which, mixing with the warm current, leads to a deterioration meteorological conditions in the Newfoundland Bank area. The water temperature in January is 0°С, in July - 12°С. The Labrador Current often carries icebergs into the ocean south of Greenland.

The Southern Equatorial Current off the coast of Brazil bifurcates into the Guiana and Brazilian Currents, to the north the Guiana Current merges with the Northern Equatorial Current. Brazilian in the south about 40 ° S. sh. connects with the course of the West Winds, from which the cold Benguela current departs to the shores of Africa. It merges with the South Tradewind, and southern ring current is closed. Towards the Brazilian from the south comes the cold Falkland.

Opened in the 60s of the XX century, the Lomonosov countercurrent has a direction from west to east, passes at a depth of 300-500 m in the form of a huge river several hundred kilometers wide.

In the southern part of the Northern Equatorial Current, eddies of an anticyclonic nature were discovered with a speed of 5.5 cm/sec. In the ocean, there are eddies of large diameters - 100-300 km (medium ones have a diameter of 50 km, small ones - 30 km). The discovery of these eddies, called synoptic, has great importance for laying the course of ships. In compiling maps with the designation of the direction and speed of movement of synoptic vortices, artificial satellites of the Earth are of great help.

The dynamics of ocean waters has a huge energy potential, which until now is almost not used. And although the ocean in most cases is less concentrated, less convenient to use than the energy of rivers, scientists believe that these are inexhaustible resources, constantly renewed. In the first place is the energy of the tides.

The first successfully operating tidal water mills were built in England (in Wales) as early as the 10th-11th centuries. Since then, they have been constantly built on the shores of Europe and North America. However, serious energy projects appeared in the 1920s. The possibilities of using tides as energy sources are most likely off the coast of France, Great Britain, the USA,. The first small-capacity tidal power plants are already in operation.

Work is underway to harness the thermal energy of the oceans. The surface layer of water in tropical latitudes can warm up to minor seasonal fluctuations. At a depth (300-500 m) the water temperature is only 8-10°C. An even sharper drop in upwelling zones. The temperature difference can be used to generate energy in water-steam turbines. The first ocean experimental thermal station with a capacity of 7 MW was created by French scientists near Abidjan (Côte d'Ivoire).

The Atlantic Ocean (map added below) is an integral part of the World Ocean. It is considered the most studied body of water on our planet. In terms of its area, it ranks second, second only to the Pacific. The Atlantic Ocean covers an area of ​​91.66 million square kilometers. km, while Quiet - at 178.684 million square meters. km. As we can see, these numbers are quite impressive.

Description of the geographical position of the Atlantic Ocean

Meridionally, the ocean stretches for 13 thousand km. In the north, it washes the shores of about. Greenland, Canada and parts of Europe, connected to the waters Arctic Ocean. In the south, the Atlantic Ocean reaches the shores of Antarctica itself. Sometimes the southern part of the Atlantic, from about 35 ° S. sh. up to 60°S sh., are classified as separate, but its existence is still a controversial issue.

The greatest width of the Atlantic Ocean is 6,700 km. In the east, it washes the western coast of Africa, Europe, connects with along the border from Cape Igolny to Queen Maud Land (in Antarctica). In the west, it brings its waters to the shores of South and North America, through connecting with the Pacific.

The geographical position of the Atlantic Ocean is such that it unites with all other major bodies of water on the planet, and also washes the shores of all continents except Australia.

Briefly about the ocean

The area of ​​the Atlantic is more than 91 million square meters. km. In percentage terms, it accounts for 25% of all the waters of the oceans. Of the total water area, 16% falls on bays and seas. There are only 16 of the latter. Sargasso, the Mediterranean and the Caribbean are the largest seas that make up the Atlantic Ocean. The map added below also shows the largest bays. This is Mexican, Maine. The Atlantic Ocean is rich in both islands and archipelagos. The most significant in terms of area: British, Greater Falkland, Iceland, Newfoundland, Greater Antilles, Bahamas, etc.

The average depths of the ocean are in the region of 3,500-4,000 m. The maximum is the Puerto Rico trench, its length is 1,754 km, its width is 97 km, and the greatest depth in this place reaches 8,742 m.

The Atlantic Ocean, or the Atlantic, is the second largest (after the Pacific) and the most developed among other water areas. From the east it is limited by the coast of South and North America, from the west - by Africa and Europe, in the north - by Greenland, in the south it merges with the Southern Ocean.

Distinctive features of the Atlantic: a small number of islands, a complex bottom topography and a heavily indented coastline.

Ocean characteristics

Area: 91.66 million sq. km, with 16% of the territory falling on the seas and bays.

Volume: 329.66 million sq. km

Salinity: 35‰.

Depth: average - 3736 m, maximum - 8742 m (Puerto Rico Trench).

Temperature: in the very south and north - about 0 ° C, at the equator - 26-28 ° C.

Currents: conventionally, 2 circulations are distinguished - the Northern (currents move clockwise) and the Southern (counterclockwise). The gyres are separated by the Equatorial inter-trade countercurrent.

Main currents of the Atlantic Ocean

Warm:

Northern trade wind - begins off the western coast of Africa, crosses the ocean from east to west and meets the Gulf Stream near Cuba.

Gulfstream- the most powerful current in the world, which carries 140 million cubic meters of water per second (for comparison: all the rivers of the world carry only 1 million cubic meters of water per second). It originates near the coast of the Bahamas, where the Florida and Antilles currents meet. Together, they give rise to the Gulf Stream, which, through the strait between Cuba and the Florida Peninsula, enters the Atlantic Ocean with a powerful stream. The current then moves north along the US coast. Approximately off the coast of the state North Carolina The Gulf Stream turns east and out into the open ocean. After about 1500 km, it meets the cold Labrador Current, which slightly changes the course of the Gulf Stream and carries it to the northeast. Closer to Europe, the current is divided into two branches: Azores and North Atlantic.

It has only recently become known that a reverse current flows 2 km below the Gulf Stream, heading from Greenland to the Sargasso Sea. This flow ice water called the Antigulf Stream.

north atlantic- continuation of the Gulf Stream, which washes the western coast of Europe and brings warmth southern latitudes providing a mild and warm climate.

Antillean- begins east of the island of Puerto Rico, flows north and joins the Gulf Stream near the Bahamas. Speed ​​— 1-1.9 km/h, water temperature 25-28°C.

Intertrade countercurrent - flow around Earth along the equator. In the Atlantic, it separates the North Equatorial and South Equatorial currents.

South trade wind (or South Equatorial) - passes through the southern tropics. The average water temperature is 30°C. When the South Equatorial Current reaches the shores of South America, it divides into two branches: caribbean, or Guiana (flows north to the coast of Mexico) and brazilian- moves south along the coast of Brazil.

Guinean located in the Gulf of Guinea. It flows from west to east and then turns south. Together with the Angolan and South Equatorial forms a cyclic course of the Gulf of Guinea.

Cold:

Lomonosov countercurrent - discovered by a Soviet expedition in 1959. It originates off the coast of Brazil and moves north. A stream 200 km wide crosses the equator and flows into the Gulf of Guinea.

Canarian- flows from north to south, towards the equator along the coast of Africa. This wide stream (up to 1 thousand km) near Madeira and canary islands meets with the Azores and Portuguese currents. Approximately in the region of 15°N. joins with the Equatorial Countercurrent.

Labrador - begins in the strait between Canada and Greenland. It flows south to the Newfoundland bank, where it meets the Gulf Stream. The waters of the current carry cold from the Arctic Ocean, and along with the stream, huge icebergs are carried south. In particular, the iceberg that destroyed the famous Titanic was brought by the Labrador Current.

Benguela- is born near the Cape of Good Hope and moves along the coast of Africa to the north.

Falkland (or Malvinas) branches off from the West Wind Current and flows north along the east coast of South America to La Plata Bay. Temperature: 4-15°C.

The course of the westerly winds encircles the globe in the region of 40-50 °S. The stream moves from west to east. In the Atlantic it branches off South Atlantic flow.

Underwater world of the Atlantic Ocean

The underwater world of the Atlantic is poorer in diversity than in pacific ocean. This is due to the fact that the Atlantic Ocean was more frozen during the ice age. But the Atlantic is richer in the number of individuals of each species.

The flora and fauna of the underwater world is clearly distributed across climatic zones.

The flora is represented mainly by algae and flowering plants (Zostera, Posidonia, Fucus). In the northern latitudes, kelp predominates, in temperate latitudes - red algae. Phytoplankton flourishes throughout the ocean at depths of up to 100 m.

The fauna is rich in species. Almost all species and classes of marine animals live in the Atlantic. Of the commercial fish, herring, sardine, and flounder are especially valued. There is an active catch of crustaceans and mollusks, whaling is limited.

The tropical belt of the Atlantic is striking in its abundance. There are many corals and many amazing species of animals: turtles, flying fish, several dozen species of sharks.

For the first time the name of the ocean is found in the writings of Herodotus (5th century BC), who calls it the sea of ​​Atlantis. And in the 1st century AD. Roman scientist Pliny the Elder writes about the vast expanse of water, which he calls Oceanus Atlantikus. But official name"Atlantic Ocean" was fixed only by the XVII century.

There are 4 stages in the history of Atlantic exploration:

1. From antiquity to the 15th century. The first documents that talk about the ocean date back to the 1st millennium BC. The ancient Phoenicians, Egyptians, Cretans and Greeks knew the coastal zones of the water area well. Preserved maps of those times with detailed measurements of depths, indications of currents.

2. Time of the Great geographical discoveries (XV-XVII centuries). The development of the Atlantic continues, the ocean becomes one of the most important trade routes. In 1498, Vasco de Gama, rounding Africa, paved the way to India. 1493-1501 Three voyages of Columbus to America. The Bermuda anomaly has been identified, many currents have been discovered, and detailed maps of depths, coastal zones, temperatures, and bottom topography have been compiled.

Expeditions of Franklin in 1770, I. Krusenstern and Yu. Lisyansky in 1804-06.

3. XIX-first half of the XX century - the beginning of scientific oceanographic research. Chemistry, physics, biology, geology of the ocean are being studied. A map of currents has been drawn up, and research is being carried out to lay a submarine cable between Europe and America.

4. 1950s - our days. Held comprehensive study all aspects of oceanography. In priority: studying the climate of different zones, identifying global atmospheric problems, ecology, mining, ensuring the movement of ships, seafood.

In the center of the Belize Barrier Reef is a unique underwater cave - the Great Blue Hole. Its depth is 120 meters, and at the very bottom there is a whole gallery of smaller caves connected by tunnels.

The only sea in the world without shores, Sargasso, is located in the Atlantic. Its borders are formed by ocean currents.

Here is one of the most mysterious places on the planet: Bermuda Triangle. The Atlantic Ocean is also the birthplace of another myth (or reality?) - the mainland of Atlantis.