is the smallest sea in the world. The average depth is only 7.4 m, the greatest is 13.5 m. The sea was formed around 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 \u200b\u200bAzov is probably the only one in the world that has had more than 100 names in its entire history! Here are just a few of them: Meotian, Karguluk, Balysyr, Samakush, Saks, Frankish, Kaffa, 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 sq. km, the average depth is 51 m. Some scientists distinguish the part of the sea between the Gulf of Bothnia and the Gulf of Finland as a separate water area - the Archipelago Sea.
In the "Tale of Bygone Years" this sea is called the Varangian, the Swedes, Germans and Danes called it the East, and in ancient Rome the sea was described as the Sarmatian Ocean. For a long time, the Baltic Sea has been considered one of the main transport routes linking Russia and Europe.
The Hebrides Sea is located between Scotland and the Hebrides. The area is 47 thousand sq. km, the average depth is 64 m.
The sea is cold, winds and hurricanes often rage over its surface, which are alternately replaced by showers and fogs. The weather here is unpredictable, 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.
In the last 100 years, the issue of building a bridge across the seas or an underwater tunnel has been widely discussed. And according to Greenpeace, the Irish Sea is considered the most radioactively polluted in the world.
It separates Central and South America, and is connected to the Pacific Ocean through the Panama Canal. Its area is 2.7 million sq. km, the average depth is 2500 m.
The sea got its name in honor of the Caribs - 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 also called the Antilles.
In the XVII-XVIII 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.
It 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 of 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 Strait of St. George, and the southern was designated as the "south-western approaches" to Great Britain. After a series of studies at the beginning of the 20th century, it was decided to single out this area as a separate sea and assign an official name to it.
Washes the southeast coast of Greenland. This small area is famous for its harsh climate and cold waters, which are 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. During the winter months, the Labrador Sea is covered by 2/3 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. Kortirial in 1500. Translated from port. "Terro do Lavrador" means "land of the plowman".
- an inland sea separating the Asian and European parts of Turkey. The area is 11.4 thousand sq. km, the average depth is 259 m.
The Sea of Marmara was formed several million years ago, its description is found in the historical writings of the ancient Greeks and Arabs. But the first scientific research here was carried out by Russians: in 1845, the expedition of M. P. Manganari, in 1890, a special scientific expedition of S. O. Makarov and I. B. Spindler.
- a unique sea, which in many ways differs from all the seas on earth.
Firstly, this is the only sea on the planet without coasts. 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 listed in the Guinness Book of Records as the largest stretch of calm water. Indeed, almost 90% of the sea is covered with sargasso - brown algae. Such a vast spot is visible even from space.
Thirdly, this is one of the safest seas in the world, as 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 this sea for laying eggs.
Until recently, the waters of the Sargasso Sea were considered the most transparent - there is little plankton, so it was possible to look deep into almost 60 meters. Unfortunately, the currents bring here a lot of garbage, including plastic waste, which seriously threaten the ecology of the water area.
Washes the northern coast of Europe, located between the British Isles, Scandinavia and the mainland. The area is 755 thousand sq. km, the average depth is 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's.
The Atlantic Ocean is second in size only to the Pacific, its area is approximately 91.56 million km². It is distinguished from other oceans by the strong indentation of the coastline, which forms numerous seas and bays, especially in the northern part. In addition, the total area of river basins flowing into this ocean or its marginal seas is much larger than that of rivers flowing into any other ocean. Another difference of the Atlantic Ocean is a relatively small number of islands and a complex bottom topography, which, thanks to underwater ridges and uplifts, forms many separate basins.
North Atlantic Ocean
borders and coastlines. The Atlantic Ocean is divided into northern and southern parts, the boundary between which is conventionally drawn along the equator. From an oceanographic point of view, however, the equatorial countercurrent, located at 5-8 ° N latitude, should be attributed to the southern part of the ocean. The northern boundary is usually drawn along the Arctic Circle. In some places this boundary is marked by underwater ridges.
In the Northern Hemisphere, the Atlantic Ocean has a heavily indented coastline. Its relatively narrow northern part is connected to the Arctic Ocean by three narrow straits. In the northeast, the Davis Strait, 360 km wide (at the latitude of the Arctic Circle), connects it with the Baffin Sea, which belongs to the Arctic Ocean. In the central part, between Greenland and Iceland, is Denmark Strait the width at its narrowest point is only 287 km. 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 - total length OK. 4000 km. in the Strait of Gibraltar, which connects the ocean with mediterranean sea, there are two oppositely directed currents one under the other. The lower position is occupied by the current from the Mediterranean Sea to the Atlantic Ocean, since the Mediterranean waters, due to more intensive evaporation from the surface, are characterized by greater salinity and, consequently, greater density.
In the tropical zone in the southwest of the North Atlantic are the Caribbean Sea and the Gulf of Mexico, connected to the ocean by the Strait of Florida. The coast of North America is indented by small bays (Pamlico, Barnegat, Chesapeake, Delaware and Long Island Sound); to the northwest are the Bays of Fundy and St. Lawrence, Belle Isle, Hudson Strait, and Hudson Bay.
The largest islands are concentrated in the northern part of the ocean; these are the British Isles, Iceland, Newfoundland, Cuba, Haiti (Hispaniola) and Puerto Rico. On the eastern outskirts There are several groups of small islands in the Atlantic Ocean - Azores, Canaries, Cape Verde. There are similar groups in the western part of the ocean. Examples include the Bahamas, Florida Keys and Lesser Antilles. The archipelagos of the Greater and Lesser Antilles form an island arc surrounding the eastern part of the Caribbean Sea. In the Pacific Ocean, such island arcs are characteristic of regions of crustal deformations. Deep-water trenches are located along the convex side of the arc.
The basin of the Atlantic Ocean is bordered by a shelf, the width of which varies. The shelf is cut through by deep gorges - the so-called. submarine canyons. Their origin is still a matter of controversy. According to one theory, the canyons were cut by rivers when the ocean level was below present. Another theory links their formation with the activity of turbidity currents. It has been suggested that turbidity currents are the main agent responsible for the deposition of sediments on the ocean floor and that it is they that cut submarine canyons.
The bottom of the northern part of the Atlantic Ocean has a complex rugged relief, formed by a combination of underwater ridges, hills, basins and gorges. Most of the ocean floor, from a depth of about 60 m to several kilometers, is covered with thin silty deposits of dark blue or bluish-green color. A relatively small area is occupied by rocky outcrops and areas of gravel-pebble and sandy deposits, as well as deep-water red clays.
Telephone and telegraph cables have been laid on the shelf in the northern part of the Atlantic Ocean to connect North America with northwestern Europe. Here, the areas of industrial fishing, which are among the most productive in the world, are confined to the area of the North Atlantic shelf.
In the central part of the Atlantic Ocean, almost repeating the outlines of the coastlines, a huge underwater mountain range approx. 16 thousand km, known as the Mid-Atlantic Ridge. This ridge divides the ocean into two approximately equal parts. Most of the peaks of this underwater ridge do not reach the surface of the ocean and are located at a depth of at least 1.5 km. Some of the highest peaks rise above ocean level and form the islands - Azores in the North Atlantic and Tristan da Cunha - in the South. In the south, the range bends around the coast of Africa and continues further north into the Indian Ocean. A rift zone extends along the axis of the Mid-Atlantic Ridge.
Surface currents in the North Atlantic Ocean move clockwise. The main elements of this large system are the warm current of the Gulf Stream directed to the north, as well as the North Atlantic, Canary and Northern Equatorial (Equatorial) currents. The Gulf Stream follows from the Florida Strait and Cuba Island in a northerly direction along the coast of the USA and approximately 40°N. sh. deviates to the northeast, changing its name to the North Atlantic Current. This current divides into two branches, one of which follows the northeast along the coast of Norway and further into the Arctic Ocean. It is because of it that the climate of Norway and all of northwestern Europe is much warmer than would be expected at latitudes corresponding to the region stretching from Nova Scotia to southern Greenland. The second branch turns south and further southwest along the coast of Africa, forming the cold Canary Current. This current moves to the southwest and joins the North Equatorial Current, which heads west towards the West Indies, where it merges with the Gulf Stream. To the north of the North Equatorial Current is an area of stagnant water, abundant in algae and known as the Sargasso Sea. Along the North Atlantic coast of North America, the cold Labrador Current passes from north to south, following from the Baffin Bay and the Labrador Sea and cooling the coast of New England.
South Atlantic Ocean
Some experts attribute to the Atlantic Ocean in the south the entire body of water up to the Antarctic ice sheet itself; others take for the southern boundary of the Atlantic an imaginary line connecting Cape Horn in South America with the Cape of Good Hope in Africa. The coastline in the southern part of the Atlantic Ocean is much less indented than in the northern part; there are also no inland seas along which the influence of the ocean could penetrate deep into the continents of Africa and South America. The only major bay on the African coast is Guinea. On the coast of South America, large bays are also few in number. The southernmost tip of this continent - Tierra del Fuego - has a rugged coastline, bordered by numerous small islands.
There are no large islands in the southern part of the Atlantic Ocean, however, there are separate isolated islands, such as Fernando de Noronha, Ascension, Sao Paulo, St. Helena, the Tristan da Cunha archipelago, and in the extreme south - Bouvet, South Georgia , South Sandwich, South Orkney, Falkland Islands.
In addition to the Mid-Atlantic Ridge, there are two main submarine mountain ranges in the South Atlantic. The whale range extends from the southwestern tip of Angola to about. Tristan da Cunha, where it joins the Mid-Atlantic. The Rio de Janeiro ridge stretches from the Tristan da Cunha Islands to the city of Rio de Janeiro and is a group of separate underwater hills.
The main current systems in the South Atlantic move counterclockwise. The South Tradewind current is directed to the west. At the 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.
The name alone of the Atlantic Ocean already reflects its vast scale. It is part of the oceans and contains significant reserves water resources. In terms of size, it ranks second (after the Pacific) place. It contains a quarter of all the water on the planet, and this is a lot - 25%. Its huge area is impressive, amounting to about 91 million square meters. km. An equally significant amount of water, which amounted to 329.7 million km³ according to the latest data. An indicator such as the average depth of the ocean is considered to be 3,600 meters. The salinity of the waters of the Atlantic Ocean is approximately 35%. To date, it is known that scientists have taken measurements and as a result have established more accurate data, according to which the average depth of the ocean is 4022 meters.
The Atlantic Ocean got its name not by chance, there are several versions of its origin. The first says that he was so named in honor of the legendary continent of Atlantis, while the second is based on the fact that he received the name from the name of the hero of ancient myths - Atlanta, who supported the entire sky on his shoulders. Even the geographical location of the mythical hero is known - at the most extreme point of the western part of the Mediterranean.
The seas of which are of great scientific interest - about 14.69 million km², which is approximately 16% of the total ocean area. The seas and bays include the following: the Irish, Baltic, North Seas, as well as the Finnish, Bothnian and If you list the seas of the Atlantic Ocean, then this is the Mediterranean, and such seas as the Balearic, Alboran, Ligurian, Adriatic, Tyrrhenian, Ionian, Aegean , Marble, Black, Azov and This list can be continued, since the Riiser-Larsen, Lazarev, Sargasso, Weddell, Caribbean, Gulfs of Maine, Mexican, St. Lawrence and Labrador, the Scotia Sea also belong here.
The seas of the Atlantic Ocean have an indirect connection with their main source, it is carried out through nearby bays and seas, therefore, there are various specific climatic conditions peculiar only to these regions, as well as a difference in diverse species of flora and fauna.
The Mediterranean Sea stretches between Asia, Europe and Africa. it is connected in the northeast with the Sea of Marmara, and the Bosporus with the Black Sea. From the southeast, it is connected through the unique Red Sea. 2,500 thousand km is the area of the Mediterranean Sea, while its volume is 3,839 thousand km³.
It communicates with the ocean through the North, and the Black through the waters of the neighboring Marmara and Mediterranean Seas. The Baltic Sea is inland, its area is 385 thousand km, the average depth is 86 meters. It received its modern outlines approximately 2.5 thousand years ago. The volume of water in it is 21,700 km3.
The Black Inland Sea also enters the seas of the Atlantic Ocean. In the southwest, it is connected to the Sea of Marmara through the Bosporus Strait. Its area is almost 413.5 thousand km, and the average depth is 1000 m (with a maximum depth of 2245 m), the volume of water in this sea is 537 thousand km. cubic.
For many centuries, a very important life-supporting phenomenon has been formed, such as the Gulf Stream. It originates in the southeast of North America. The width of the current of the Atlantic Ocean is 75 km, and its speed is 6-30 km/h. It is characterized by a warm upper layer of water with a temperature of 26 degrees and a speed that lies within such limits - 6-30 km / h. Warm provide the European states, which are located on its shores, with a mild and favorable climate, very comfortable for living. The heat that the Gulf Stream emits is equivalent to the amount of heat that 1 million nuclear power plants can generate.
ATLANTIC OCEAN(Latin name Mare Atlanticum, Greek 'Ατλαντίς - denoted the space between the Strait of Gibraltar and the Canary Islands, the whole ocean was called Oceanus Occidentalis - Western ok.), the second largest ocean on Earth (after the Pacific ok.), part World approx. Modern name first appeared in 1507 on the map of the Lorraine cartographer M. Waldseemüller.
Physical-geographical sketch
General information
In the north, the border of A. o. with the Arctic basin approx. runs along the east. Hudson Strait entrance, then through Davis Strait. and along the coast. Greenland to Cape Brewster, through the Danish Strait. to Cape Rydinupyur on about. Iceland, along its coast to Cape Gerpir (Terpire), then to the Faroe Islands, then to the Shetland Islands and along 61 ° N. sh. to the coast of the Scandinavian Peninsula. In the east of A. about. bounded by the shores of Europe and Africa, in the west - by the shores of the North. America and South. America. The border of A. o. with Indian ca. carried out along the line passing from Cape Igolny along the meridian 20 ° E. to the coast of Antarctica. The border with the Pacific carried out from Cape Horn along the meridian 68 ° 04′ W. or the shortest distance from Yuzh. America to the Antarctic Peninsula through the strait. Drake, from Fr. Oste to Cape Sternek. South part A. o. sometimes called the Atlantic sector of the Southern Ocean, drawing the border along the subantarctic zone. convergence (approximately 40° S). In some works division A. about is offered. to Sev. and Yuzh. The Atlantic Oceans, but it is more common to consider it as a single ocean. A. o. - the most biologically productive of the oceans. It contains the longest underwater ocean. ridge - Mid-Atlantic Ridge; the only sea that does not have solid shores, limited by currents - Sargasso Sea; hall. fandi with the highest tidal wave; to the basin of A. o. applies Black Sea with a unique hydrogen sulfide layer.
A. o. stretches from north to south for almost 15 thousand km, its smallest width is approx. 2830 km in the equatorial part, the largest - 6700 km (along the parallel of 30 ° N). Area A. o. with seas, bays and straits 91.66 million km 2, without them - 76.97 million km 2. The volume of water is 329.66 million km 3, without seas, bays and straits - 300.19 million km 3. Wed depth 3597 m, maximum - 8742 m (chute Puerto Rico). The most easily accessible for development shelf zone of the ocean (with depths up to 200 m) occupies approx. 5% of its area (or 8.6%, if we take into account the seas, bays and straits), its area is larger than in the Indian and Pacific Oceans, and significantly less than in the Arctic Ocean. Areas with depths from 200 m to 3000 m (continental slope zone) occupy 16.3% of the ocean area, or 20.7%, taking into account the seas and bays, more than 70% - the ocean floor (abyssal zone). See map.
Seas
In the basin of A. o. - numerous. seas, which are divided into: internal - Baltic, Azov, Black, Marmara and Mediterranean (in the latter, in turn, the seas are distinguished: Adriatic, Alboran, Balearic, Ionian, Cypriot, Ligurian, Tyrrhenian, Aegean); interisland - Irish and int. sea west. the coast of Scotland; marginal - Labrador, Northern, Sargasso, Caribbean, Scotia (Scotia), Weddell, Lazarev, zap. part of Riiser-Larsen (see separate articles on the seas). The largest bays of the ocean: Biscay, Bristol, Guinean, Mexican, Maine, St. Lawrence. Major straits oceans: Great Belt, Bosphorus, Gibraltar, Dardanelles, Danish, Davis, Drake, Oresund (Sund), Cabota, Kattegat, Kerch, English Channel (including Pas de Calais), Small Belt, Messinian, Skagerrak, Florida , Yucatan.
Islands
Unlike other oceans, in A. o. there are few seamounts, guyots and coral reefs, and there are no coastal reefs. The total area of \u200b\u200bthe islands of A. o. OK. 1070 thousand km 2. Main groups of islands are located on the outskirts of the continents: British (Great Britain, Ireland, etc.) - the largest in area, Greater Antilles (Cuba, Haiti, Jamaica, etc.), Newfoundland, Iceland, the Tierra del Fuego archipelago (Land of Fire, Oste, Navarino) , Marajo, Sicily, Sardinia, Lesser Antilles, Falkland (Malvinas), Bahamas, etc. Small islands are found in the open ocean: Azores, Sao Paulo, Ascension, Tristan da Cunha, Bouvet (on the Mid-Atlantic Ridge), etc. .
coast
Coastline in the north. parts of A. o. heavily indented (see also Shore ), almost all major inland seas and bays are located here, in the south. parts of A. o. the banks are slightly indented. The coast of Greenland, Iceland and the coast of Norway preim. tectonic-glacial division of fjord and fiard types. To the south, in Belgium, they give way to sandy shallow shores. Coast of Flanders arr. arts. origin (coastal dams, polders, canals, etc.). The coast of UK and about. Ireland abrasion-bay, high limestone cliffs alternate with sandy beaches and muddy lands. The Cotentin Peninsula has rocky shores, sandy and gravel beaches. Sev. the coast of the Iberian Peninsula is composed of rocks, to the south, off the coast of Portugal, sandy beaches predominate, often fencing off lagoons. Sandy beaches also border the shores of the West. Sahara and Mauritania. To the south of Cape Zeleny there are leveled abrasion-bay shores with mangrove thickets. Zap. the Ivory Coast section has an accumulative coast with rocky headlands. To the southeast, to the vast delta of the river. Niger, - accumulative coast with means. the number of spits, lagoons. In the southwest Africa - accumulative, less often abrasion-bay shores with extensive sandy beaches. The shores of southern Africa of the abrasion-bay type are composed of solid crystalline. breeds. Coasts of the Arctic. Canadas are abrasive, with high cliffs, glacial deposits and limestones. In east. Canada and sowing. parts of the hall. St. Lawrence are intensively eroded limestone and sandstone cliffs. To the west and south of the hall. St. Lawrence - wide beaches. On the shores of the Canadian provinces of Nova Scotia, Quebec, Newfoundland - outcrops of solid crystalline. breeds. From about 40 ° N. sh. to Cape Canaveral in the USA (Florida) - alternation of leveled accumulative and abrasion types of coasts, composed of loose rocks. Coast of the Gulf of Mexico. low-lying, bordered by mangroves in Florida, sand barriers in Texas, and deltaic shores in Louisiana. On the Yucatan Peninsula - cemented beach sediments, to the west of the peninsula - an alluvial-marine plain with coastal ridges. On the coast of the Caribbean Sea, abrasion and accumulation areas alternate with mangrove swamps, alongshore barriers, and sandy beaches. South of 10° N. sh. accumulative banks are common, composed of material carried out from the mouth of the river. Amazon and other rivers. In the northeast of Brazil - a sandy coast with mangroves, interrupted by river estuaries. From Cape Kalkanyar to 30°S sh. - high deep coast of abrasion type. To the south (off the coast of Uruguay) there is an abrasion-type coast composed of clays, loess and sand and gravel deposits. In Patagonia, the coasts are represented by high (up to 200 m) cliffs with loose deposits. The shores of Antarctica are 90% composed of ice and belong to the ice and thermal abrasion type.
Bottom relief
At the bottom of A. o. distinguish the following major geomorphological. provinces: the underwater margin of the continents (shelf and continental slope), the ocean floor (deep basins, abyssal plains, zones of abyssal hills, uplifts, mountains, deep-sea trenches), mid-oceanic. ridges.
The boundary of the continental shelf (shelf) A. o. takes place on Wed. at depths of 100–200 m, its position can vary from 40–70 m (near Cape Hatteras and the Florida Peninsula) to 300–350 m (Cape Weddell). The shelf width varies from 15–30 km (Northeast Brazil, Iberian Peninsula) to several hundred km (Northern Sea, Gulf of Mexico, Newfoundland Bank). In high latitudes, the shelf relief is complex and bears traces of glacial influence. Numerous uplifts (banks) are separated by longitudinal and transverse valleys or trenches. Off the coast of Antarctica on the shelf are ice shelves. At low latitudes, the shelf surface is more leveled, especially in the areas where terrigenous material is carried out by rivers. It is crossed by transverse valleys, often turning into canyons of the continental slope.
The slope of the continental slope of the ocean is cf. 1–2° and varies from 1° (areas of Gibraltar, the Shetland Islands, parts of the coast of Africa, etc.) to 15–20° off the coast of France and the Bahamas. The height of the continental slope varies from 0.9–1.7 km near the Shetland Islands and Ireland to 7–8 km in the area of the Bahamas and the Puerto Rico Trench. Active margins are characterized by high seismicity. The surface of the slope is dissected in places by steps, ledges and terraces of tectonic and accumulative origin and longitudinal canyons. At the foot of the continental slope, gently sloping hills are often located. up to 300 m and shallow underwater valleys.
In the middle part of the bottom of A. o. is the largest mountain system of the Mid-Atlantic Ridge. It extends from about. Iceland to about. Bouvet at 18,000 km. The width of the ridge is from several hundred to 1000 km. The crest of the ridge runs close to the midline of the ocean, dividing it to the east. and app. parts. On both sides of the ridge there are deep-sea basins separated by bottom uplifts. In zap. parts of A. o. Basins are distinguished from north to south: Labradorskaya (with depths of 3000–4000 m); Newfoundland (4200–5000 m); North American Basin(5000–7000 m), which includes the abyssal plains of Som, Hatteras and Nares; Guiana (4500–5000 m) with the Demerara and Ceara plains; brazilian basin(5000–5500 m) with the abyssal plain of Pernambuco; Argentinean (5000–6000 m). In east. parts of A. o. basins are located: Western European (up to 5000 m), Iberian (5200–5800 m), Canary (over 6000 m), Zeleny Cape (up to 6000 m), Sierra Leone (about 5000 m), Guinea (over 6000 m). 5000 m), Angolan (up to 6000 m), Cape (over 5000 m) with the abyssal plains of the same name. To the south is the African-Antarctic Basin with the abyssal Weddell Plain. The bottoms of deep-water basins at the foot of the Mid-Atlantic Ridge are occupied by the zone of abyssal hills. The basins are separated by the Bermuda, Rio Grande, Rockall, Sierra Leone, and other uplifts, and by the Kitovy, Newfoundland, and other ridges.
Seamounts (isolated conical elevations 1,000 m or more high) at the bottom of the sea. concentrated preim. in the Mid-Atlantic Ridge. In the deep-water part, large groups of seamounts are found north of Bermuda, in the Gibraltar sector, near the northeast. ledge South. America, in the Guinea Hall. and west of South. Africa.
Deep sea trenches of Puerto Rico, Caiman(7090 m), South Sandwich Trench(8264 m) are located near the island arcs. gutter Romansh(7856 m) is a major fault. The steepness of the slopes of deep-sea trenches is from 11° to 20°. The bottom of the troughs is flat, leveled by accumulation processes.
Geological structure
A. o. arose as a result of the collapse of the Late Paleozoic supercontinent Pangea during the Jurassic. It is characterized by a sharp predominance of passive margins. A. o. borders on adjacent continents transform faults south of about. Newfoundland, along the north. coast of the Gulf of Guinea., along the Falkland underwater plateau and the Agulhas plateau in the south. parts of the ocean. Active margins are observed at areas (in the region of the Lesser Antilles arc and the arc of the South Sandwich Islands), where the subsidence occurs ( subduction) lithosphere A. o. The Gibraltar subduction zone, limited in length, has been identified in the Gulf of Cadiz.
In the Mid-Atlantic Ridge, the bottom is moving apart ( spreading) and the formation of oceanic. bark at a rate of up to 2 cm per year. Characterized by high seismic and volcanic. activity. In the north, paleospreading ridges branch off from the Mid-Atlantic Ridge into Cape Labrador and into the Bay of Biscay. In the axial part of the ridge, a rift valley is pronounced, which is absent in the extreme south and on the b. including the Reykjanes Ridge. Within its limits - volcanic. uplifts, solidified lava lakes, basaltic lava flows in the form of pipes (pillow-basalts). To the Center. The Atlantic found fields of metal-bearing hydrotherm, many of which form hydrothermal structures at the outlet (composed of sulfides, sulfates and metal oxides); installed metaliferous sediments. At the foot of the slopes of the valley there are screes and landslides, consisting of blocks and crushed stone of oceanic rocks. bark (basalts, gabbro, peridotites). The age of the crust within the Oligocene ridge is modern. The Mid-Atlantic Ridge separates the zones west. and east. abyssal plains, where oceanich. The basement is covered by a sedimentary cover, the thickness of which increases in the direction of the continental foothills up to 10–13 km due to the appearance of older horizons in the section and the influx of clastic material from land. In the same direction, the age of the oceans is increasing. crust, reaching the Early Cretaceous (north of Middle Jurassic Florida). Abyssal plains are practically aseismic. The Mid-Atlantic Ridge is crossed by numerous transform faults leading to adjacent abyssal plains. The thickening of such faults is observed in the equatorial zone (up to 12 per 1700 km). The largest transform faults (Vima, São Paulo, Romansh, etc.) are accompanied by deep incisions (troughs) on the ocean floor. The entire section of the oceanic is opened in them. bark and partly upper mantle; protrusions (cold intrusions) of serpentinized peridotites are widely developed, forming ridges elongated along the strike of the faults. Mn. transform faults are transoceanic, or main (demarcation). In A. o. there are so-called. intraplate uplifts represented by underwater plateaus, aseismic ridges and islands. They have an oceanic a bark of the increased power also have hl. arr. volcanic origin. Many of them were formed as a result of the action mantle plumes; some originated at the intersection of the spreading ridge by large transform faults. To the volcanic uplifts include: about. Iceland, about Bouvet, oh Madeira, the Canary Islands, the Cape Verde, the Azores, the paired uplifts of Sierra and Sierra Leone, the Rio Grande and the Whale Range, the Bermuda Uplift, the Cameroon group of volcanoes, and others. there are intraplate uplifts of non-volcanic. nature, which includes the underwater plateau of Rockall, separated from the British Isles by the same name. trog. The plateau represents microcontinent, detached from Greenland in the Paleocene. Another micro-continent that also broke away from Greenland is the Hebrides in northern Scotland. The underwater marginal plateaus off the coast of Newfoundland (Great Newfoundland, Flemish Cap) and off the coast of Portugal (Iberian) separated from the continents as a result of rifting at the end of the Jurassic - the beginning of the Cretaceous.
A. o. is divided by transoceanic transform faults into segments with different opening times. From north to south, the Labrador-British, Newfoundland-Iberian, Central, Equatorial, Southern and Antarctic segments are distinguished. The opening of the Atlantic began in the Early Jurassic (about 200 million years ago) from the Central Segment. In the Triassic-Early Jurassic, oceanic spreading. the bottom was preceded by the continental rifting, traces of which are recorded in the form of semigrabens filled with clastic deposits on the Amer. and north - afri. the outskirts of the ocean. At the end of the Jurassic - the beginning of the Cretaceous, the Antarctic segment began to open up. In the early Cretaceous, spreading was experienced by Yuzh. segment in South. Atlantic and Newfoundland-Iberian segment in the North. Atlantic. The opening of the Labrador-British segment began at the end of the Early Cretaceous. At the end of the Late Cretaceous, the basin of the Labrador Sea arose here as a result of spreading on the side axis, which continued until the late Eocene. Sev. and Yuzh. The Atlantic united in the middle of the Cretaceous - Eocene during the formation of the Equatorial segment.
Bottom sediments
The thickness of the modern bottom sediments varies from a few m in the zone of the crest of the Mid-Atlantic Ridge to 5–10 km in the zones of transverse faults (for example, in the Romansh trench) and at the foot of the continental slope. In deep-sea basins, their thickness varies from several tens to 1000 m. St. 67% of the area of the ocean floor (from Iceland in the north to 57–58 ° S) is covered with calcareous deposits formed by the remains of shells of planktonic organisms (main sample foraminifera, coccolithophorid). Their composition varies from coarse sands (at depths up to 200 m) to silts. At depths greater than 4500–4700 m, calcareous muds are replaced by polygenic and siliceous planktonic sediments. The first take approx. 28.5% of the ocean floor area, lining the bottom of the basins, and represented red deep ocean clay(deep-sea clay silts). These sediments contain the amount of manganese (0.2–5%) and iron (5–10%) and a very small amount of carbonate material and silicon (up to 10%). Siliceous planktonic sediments occupy approx. 6.7% of the ocean floor area, of which diatom silts (formed by the skeletons of diatoms) are the most common. They are common off the coast of Antarctica and on the shelf of the Southwest. Africa. Radiolarian oozes (formed by skeletons of radiolarians) meet hl. arr. in the Angolan Basin. Along the coasts of the ocean, on the shelf and partly on the continental slopes, terrigenous sediments of various compositions (gravel-pebble, sandy, clayey, etc.) are developed. The composition and thickness of terrigenous sediments are determined by the bottom relief, the activity of solid material supply from land, and the mechanism of their transfer. Glacial precipitation carried by icebergs is distributed along the coast of Antarctica, about. Greenland, about. Newfoundland, Labrador Peninsula; composed of weakly sorted detrital material with the inclusion of boulders, mostly in the south of the A. o. Sediments (from coarse sand to silt) formed from pteropod shells are often found in the equatorial part. Coral sediments (coral breccias, pebbles, sands and silts) are localized in the Gulf of Mexico, the Caribbean Sea and near the northeast. the coasts of Brazil; their ultimate depth is 3500 m. Volcanic sediments are developed near the volcanic. islands (Iceland, Azores, Canaries, Cape Verde, etc.) and are represented by fragments of volcanic. rocks, slag, pumice, volcanic. ashes. Modern chemogenic sediments are found on the Great Bahama Bank, in the Florida-Bahamas, Antilles regions (chemogenic and chemogenic-biogenic carbonates). In the basins of the North American, Brazilian, Green Cape there are ferromanganese nodules; their composition in AO: manganese (12.0–21.5%), iron (9.1–25.9%), titanium (up to 2.5%), nickel, cobalt, and copper (tenths of a percent ). Phosphorite concretions appear at depths of 200–400 m near the east. US coast and north-west. coast of Africa. Phosphorites are distributed along the east. coast of A. o. - from the Iberian Peninsula to Cape Agulhas.
Climate
Due to the large length of A. o. its waters are located in almost all natural climates. zones - from the subarctic in the north to the antarctic in the south. From the north and south, the ocean is widely open to the influence of the Arctic. and antarctic. waters and ice. The lowest air temperature is observed in the polar regions. Over the coast of Greenland, the temperature can drop to -50 ° C, and in the south. part of Cape Weddell recorded a temperature of –32.3 °C. In the equatorial region, the air temperature is 24–29 ° C. The pressure field over the ocean is characterized by a successive change of stable large baric formations. Above the ice domes of Greenland and Antarctica - anticyclones, in temperate latitudes North. and Yuzh. hemispheres (40–60°) - cyclones, at lower latitudes - anticyclones, separated by a zone of low pressure near the equator. This baric structure supports tropical. and equatorial latitudes steady winds east. directions (trade winds), in temperate latitudes - strong winds west. directions, which received the names of the sailors. "roaring forties". Strong winds are also characteristic of the Bay of Biscay. In the equatorial region, the interaction of the sowing. and south. baric systems leads to frequent tropical. cyclones (tropical hurricanes), the greatest activity of which is observed from July to November. Tropical horizontal dimensions. cyclones up to several hundred km. The wind speed in them is 30–100 m/s. They move, as a rule, from east to west at a speed of 15-20 km / h and reach their greatest strength over the Caribbean and the Gulf of Mexico. In areas of low pressure in temperate and equatorial latitudes, precipitation is frequent and heavy clouds are observed. So, at the equator, St. 2000 mm of precipitation per year, in temperate latitudes - 1000–1500 mm. In areas of high pressure (subtropics and tropics), the amount of precipitation decreases to 500–250 mm per year, and in areas adjacent to the desert coasts of Africa and in the South Atlantic High, to 100 mm or less per year. In areas where warm and cold currents meet, fogs are frequent, for example. in the Newfoundland Bank area and in the hall. La Plata.
Hydrological regime
Rivers and water balance with. In the basin of A. o. 19,860 km 3 of water are annually carried out by rivers, this is more than in any other ocean (about 45% of the total flow into the World Ocean). The largest rivers (with an annual flow of over 200 km 3): Amazon, Mississippi(flows into the Gulf of Mexico.), Saint Lawrence river, Congo, Niger, Danube(flows into the Black Sea) Paraná, Orinoco, Uruguay, Magdalena(flows into the Caribbean). However, the fresh water balance of A. o. negative: evaporation from its surface (100–125 thousand km 3 / year) significantly exceeds atmospheric precipitation (74–93 thousand km 3 / year), river and underground runoff (21 thousand km 3 / year) and ice melting and icebergs in the Arctic and Antarctic (about 3 thousand km 3 / year). The deficit of the water balance is compensated by the inflow of waters, Ch. arr. from the Pacific Ocean, through the Drake Strait with the course of the West Winds, 3,470 thousand km 3 / year enter in Pacific ok. only 210 thousand km 3 / year go. From the Arctic ca. through numerous straits in A. about. 260 thousand km 3 / year and 225 thousand km 3 / year are supplied by the Atlantic. water flows back into the Arctic Ocean. Water balance with Indian c. negative, in the Indian apprx. with the course of the West Winds, 4976 thousand km 3 / year are taken out, and come back with the Coastal Antarctic. current, deep and bottom waters, only 1692 thousand km 3 / year.
Temperature regime m. Wed. the temperature of the ocean waters as a whole is 4.04 ° C, and that of surface waters is 15.45 ° C. The distribution of water temperature on the surface is asymmetric with respect to the equator. The strong influence of the Antarctic. waters leads to the fact that the surface waters of the South. hemisphere almost 6 °C colder than the northern hemisphere, the most warm waters the open part of the ocean (thermal equator) are between 5 and 10 ° N. sh., i.e., shifted north of the geographic. equator. Features of large-scale water circulation lead to the fact that the water temperature on the surface near the west. coasts of the ocean are about 5 °C higher than those of the east. The warmest water temperature (28–29 ° C) on the surface is in the Caribbean and the Gulf of Mexico. in August, the lowest - off the coast of about. Greenland, about. Baffin Island, Labrador Peninsula and Antarctica, south of 60 °, where even in summer the water temperature does not rise above 0 ° C. The temperature of the waters in the layer Ch. thermocline (600–900 m) is approx. 8–9 °C, deeper, in intermediate waters, descends at cf. up to 5.5 °C (1.5–2 °C in Antarctic intermediate waters). In deep waters, the water temperature in cf. 2.3 °C, in the bottom 1.6 °C. At the very bottom, the temperature of the water increases slightly due to geothermal. heat flow.
Salinity In the waters of A. o. contains approx. 1.1×10 16 tons of salts. Wed the salinity of the waters of the entire ocean is 34.6‰, and that of surface waters is 35.3‰. The highest salinity (over 37.5‰) is observed on the surface in the subtropical. areas where the evaporation of water from the surface exceeds its inflow with atmospheric precipitation, the smallest (6–20‰) in the estuarine sections of large rivers flowing into the ocean. From the subtropics to high latitudes, salinity on the surface decreases to 32–33‰ under the influence of precipitation, ice, river and surface runoff. In temperate and tropical areas max. salinity values are on the surface, an intermediate salinity minimum is observed at depths of 600–800 m. parts of A. o. are characterized by a deep salinity maximum (more than 34.9‰), which is formed by highly saline Mediterranean waters. Deep waters of A. o. have a salinity of 34.7–35.1‰ and a temperature of 2–4 °C, near-bottom, occupying the deepest depressions of the ocean, respectively 34.7–34.8‰ and 1.6 °C.
Density The density of water depends on temperature and salinity; temperature is of greater importance in the formation of the water density field. Waters with the lowest density are located in the equatorial and tropical regions. zones with a high water temperature and a strong influence of the flow of such rivers as the Amazon, Niger, Congo, etc. (1021.0–1022.5 kg / m 3). In the south part of the ocean, the density of surface waters increases to 1025.0–1027.7 kg/m 3 , in the northern part – up to 1027.0–1027.8 kg/m 3 . Density of deep waters A. o. 1027.8–1027.9 kg / m 3.
Ice regime m. In the north. parts of A. o. first-year ice is formed Ch. arr. in the inner seas of temperate latitudes, multi-year ice is carried out from the Arctic approx. The boundary of the distribution of the ice cover in the sowing. parts of A. o. changes significantly in winter period pack ice can reach dec. years 50–55°N sh. There is no ice in summer. Antarctic border. In winter, multi-year ice passes at a distance of 1600-1800 km from the coast (approximately 55 ° S), in summer (February - March) ice is found only in the coastal strip of Antarctica and in Cape Weddell. Main icebergs are supplied by the ice sheets and ice shelves of Greenland and Antarctica. The total mass of icebergs coming from the Antarctic. glaciers, estimated at 1.6 × 10 12 tons per year, main. their source is the Filchner Ice Shelf in Cape Weddell. From the glaciers of the Arctic to the A. O. icebergs with a total mass of 0.2–0.3 × 10 12 tons arrive per year, in the main. from the Jacobshavn glacier (near Disko Island off the western coast of Greenland). Wed arctic lifespan. icebergs approx. 4 years, Antarctic a little more. The border of distribution of icebergs in sowing. parts of the ocean 40 ° N. sh., but in otd. cases they were observed up to 31 ° C. sh. In the south part of the boundary passes at 40 ° S. sh., in the center. parts of the ocean and at 35 ° S. sh. on the app. and east. periphery.
I flow. Water circulation A. o. subdivided into 8 quasi-stationary oceanic. gyres located almost symmetrically about the equator. From low to high latitudes in the North. and Yuzh. hemispheres are tropical. anticyclonic, tropical cyclonic, subtropical anticyclonic, subpolar cyclonic. oceanic cycles. Their boundaries, as a rule, are Ch. oceanic currents. A warm current begins off the Florida Peninsula Gulfstream. Taking in the warm waters Antilles Current and Florida Current, the Gulf Stream heads northeast and splits into several branches at high latitudes; the most significant of them are Irminger Current, which carries warm water into Davis Strait, the North Atlantic Current, norwegian current, going to the Norwegian Sea and further to the northeast, along the coast of the Scandinavian Peninsula. To meet them from Devisova Prospekt. comes out cold Labrador Current, whose waters can be traced off the coast of America to almost 30 ° N. sh. From Danish Strait. the cold East Greenland current flows into the ocean. In low latitudes A. about. warm temperatures move from east to west northern trade winds and South trade winds, between them, approximately 10 ° N. sh., from west to east there is an Intertrade countercurrent, which is active Ch. arr. summer in Sev. hemisphere. separates from the southern trade winds brazilian current, which runs from the equator to 40 ° S. sh. along the coast of America. Sev. branch of the South trade wind currents forms Guiana current, which is directed from south to northwest to the connection with the waters of the Northern trade winds. Off the coast of Africa from 20 ° N. sh. the warm Guinea current passes to the equator, in the summer the Intertrade countercurrent connects with it. In the south parts of A. o. crosses the cold West winds flow(Antarctic circumpolar current), which is included in the A. about. through the strait Drake, descends to 40 ° S. sh. and goes to the Indian ca. south of Africa. The Falkland current separates from it, reaching along the coast of America almost to the mouth of the river. Parana, the Benguela Current, running along the coast of Africa almost to the equator. Cold canary current runs from north to south - from the shores of the Iberian Peninsula to the Cape Verde Islands, where it passes into the Northern trade winds.
Deep circulation during e. Deep circulation and structure of waters A. o. are formed as a result of a change in their density during cooling of waters or in zones of mixing of waters decomp. origin, where the density increases as a result of the mixing of waters with decomp. salinity and temp. Subsurface waters are formed in the subtropical. latitudes and occupy a layer with a depth of 100–150 m to 400–500 m, with a temperature of 10–22 °C and a salinity of 34.8–36.0‰. Intermediate waters are formed in the subpolar regions and are located at depths from 400–500 m to 1000–1500 m, with a temperature of 3 to 7 °C and a salinity of 34.0–34.9‰. The circulation of subsurface and intermediate waters is generally anticyclonic. character. Deep waters are formed in high latitudes. and south. parts of the ocean. Waters formed in the Antarctic area, have the highest density and spread from south to north in the bottom layer, their temperature varies from negative (in high southern latitudes) to 2.5 ° C, salinity 34.64–34.89‰. Waters formed in high sowing. latitudes, move from north to south in a layer from 1500 to 3500 m, the temperature of these waters is from 2.5 to 3 ° C, salinity is 34.71–34.99‰. In the 1970s V. N. Stepanov and, later, V. S. Broker substantiated the scheme of planetary interoceanic transfer of energy and matter, which received the name. "global conveyor" or "global thermohaline circulation of the World Ocean". According to this theory, the relatively salty North Atlantic. waters reach the coast of Antarctica, mix with supercooled shelf water and, passing through the Indian Ocean, end their journey in the sowing. parts of the Pacific Ocean.
Tides and waves e. Tides in A. o. preim. semi-diurnal. Tidal wave height: 0.2–0.6 m in the open part of the ocean, a few cm in the Black Sea, 18 m in the bay. Fundy (the northern part of the Gulf of Maine in North America) is the highest in the world. The height of wind waves depends on the speed, exposure time and wind acceleration; during strong storms it can reach 17–18 m. 22–26 m.
Flora and fauna
The large length of the A. O., the variety of climatic. conditions, that is. inflow fresh water and major upwellings provide a variety of living conditions. In total, approx. 200,000 species of plants and animals (including about 15,000 fish species, about 600 species of cephalopods, about 100 species of whales and pinnipeds). Life is distributed very unevenly in the ocean. There are three main the type of zonality of the distribution of life in the ocean: latitudinal, or climatic, vertical and circumcontinental. The density of life and its species diversity decrease with distance from the coast towards the open ocean and from the surface to deep waters. Species diversity also decreases from tropical. latitudes to high.
Planktonic organisms (phytoplankton and zooplankton) are the basis of the food chain in the ocean, osn. their mass lives in the upper zone of the ocean, where light penetrates. The highest plankton biomass is in high and temperate latitudes during spring and summer blooms (1–4 g/m3). During the year, biomass can change by 10–100 times. Main phytoplankton species - diatoms, zooplankton - copepods and euphausids (up to 90%), as well as chaetognaths, hydromedusae, ctenophores (in the north) and salps (in the south). At low latitudes, the plankton biomass varies from 0.001 g/m 3 in the centers of anticyclonics. gyres up to 0.3–0.5 g/m 3 in the Gulf of Mexico and Guinea. Phytoplankton is represented by Ch. arr. coccolithins and peridineas, the latter can develop in coastal waters in large quantities, causing catastrophic. red tide phenomenon. Low-latitude zooplankton is represented by copepods, chaetognaths, hyperids, hydromedusae, siphonophores, and other species. There are no clearly pronounced dominant zooplankton species in low latitudes.
Benthos is represented by large algae (macrophytes), which b. hours grow at the bottom of the shelf zone to a depth of 100 m and cover approx. 2% of the total area of the ocean floor. The development of phytobenthos is observed in those places where there are suitable conditions—soils suitable for fastening to the bottom, the absence or moderate speeds of near-bottom currents, and so on. main part of the phytobenthos is made up of kelp and red algae. In the temperate zone, parts of the sea, along the American and European coasts, are brown algae (fucus and ascophyllum), kelp, desmarestia, and red algae (furcellaria, ahnfeltia, and others). Zostera is common on soft soils. In the temperate and cold zones of the south. parts of A. o. brown algae predominate. In the tropical in the littoral zone, due to strong heating and intense insolation, vegetation on the ground is practically absent. A special place is occupied by the ecosystem of the Sargasso m., where floating macrophytes (mainly three types algae of the genus Sargassum) form clusters on the surface in the form of ribbons ranging in length from 100 m to several. kilometers.
The main part of the nekton biomass (actively swimming animals - fish, cephalopods, and mammals) are fish. The largest number of species (75%) lives in the shelf zone; with depth and with distance from the coast, the number of species decreases. For cold and temperate zones are characteristic: from fish - dec. species of cod, haddock, saithe, herring, flounder, catfish, conger eel, etc., herring and polar sharks; from mammals - pinnipeds (harp seal, hooded seal, etc.), decomp. species of cetaceans (whales, sperm whales, killer whales, pilot whales, bottlenose whales, etc.).
There is a great similarity between the faunas of temperate and high latitudes of both hemispheres. At least 100 species of animals are bipolar, that is, they are characteristic of both temperate and high zones. For the tropical A.'s zones about. characteristic: from fish - dec. sharks, flying fish, sailboats, decomp. species of tuna and glowing anchovies; from animals - sea turtles, sperm whales, river dolphin inia; numerous and cephalopods - diff. species of squid, octopus, etc.
Deep-sea fauna (zoobenthos) A. o. represented by sponges, corals, echinoderms, crustaceans, mollusks, decomp. worms.
Research history
Allocate three stages of research And. The first is characterized by the establishment of the boundaries of the ocean and the discovery of its individual objects. AT 12- 5th century BC e. Phoenicians, Carthaginians, Greeks and Romans left descriptions of maritime wanderings and the first sea charts. Their voyages reached the Iberian Peninsula, England and the mouth of the Elbe. In the 4th c. BC e.Piteas(Pytheas) while sailing to the North. Atlantic, he determined the coordinates of a number of points and described the tidal phenomena in the A. O. By the 1st century n. e. include references to the Canary Islands. In the 9th-10th centuries. Normans (RowdyEirik and his son Leif Eirikson) crossed the ocean, visited Iceland, Greenland, Newfoundland and explored the shores of the North. America under 40° c. sh. In the eraGreat geographical discoveries(mid. 15th - mid. 17th centuries) navigators (mainly the Portuguese and Spaniards) mastered the way to India and China along the coast of Africa. The most outstanding voyages during this period were made by the Portuguese B.Diashem(1487), Genoese H.Columbus(1492–1503), the Englishman J.Cabot(1497) and the Portuguese Vasco dagama(1498); for the first time trying to measure the depths of the open parts of the ocean and the speed surface currents. The first bathymetric map (depth map) was compiled in Spain in 1523. In 1520 F.Magellanfirst passed from A. o. in Pacific ok. strait, later named after him. In the 16th and 17th centuries Atlantic is intensively studied. coast of the North. America (English J.Davis, 1576–78, G. Hudson, 1610, W. Baffin, 1616, and other sailors whose names can be found on the map of the ocean). The Falkland Islands were discovered in 1591–92. South shores of A. o. - the mainland Antarctica - were discovered and first described by Rus. antarctic expedition F.F.Bellingshausen and M.P. Lazarevain 1819–21. This completed the study of the boundaries of the ocean.
The second stage is characterized by the study of physical. properties of ocean waters, temperature, salinity, currents, etc. In 1749, the Englishman G. Ellis made the first temperature measurements at various depths, repeated by the Englishman J. cook(1772), Swiss O. Saussure(1780), Russian. I.F. Kruzenshtern(1803) and others. In the 19th century. A. o. becomes a testing ground for testing new methods of studying depths, new equipment and new approaches to the organization of work. For the first time, bathometers, deep-sea thermometers, thermal depth gauges, deep-sea trawls and dredges are used. Of the most significant expeditions can be noted Rus. sailing on the ships "Rurik" (1815-18) and "Enterprise" (1823–26) under the direction of O. E.Kotzebue(1815–18); English on "Erebus" and "Terror" under the leadership of J.K.Ross(1840–43); Amer. on the "Arctic" under the leadership of M.F.Maury(1856). True complex oceanographic ocean exploration began with an expedition in English. corvette« Challenger "led by W. Thomson (1872-76). The following significant expeditions were carried out on the ships Gazelle (1874-76), Vityaz (1886-89), Valdivia (1898-99), Gauss (1901-03). From 1885 to 1922, a great contribution to the study of A. o. introduces Prince Albert I of Monaco, who organized and led expeditionary research on the yachts Irendel, Princess Alice, Irendel II, Princess Alice II in the north. parts of the ocean. In the same years he organized the Oceanographic Museum in Monaco. Since 1903, work began on the "standard" sections in the North Atlantic under the leadership of the International Council for the Study of the Sea (ICES) - the first international oceanographic. scientific organization that existed before the 1st World War.
The most significant expeditions between the world wars were carried out on the ships Meteor, Discovery II, Atlantis. In 1931, the International Council of Scientific Unions (ICSU) was formed, which is still active today and organizes and coordinates ocean research.
After the 2nd World War, the echo sounder began to be widely used to study the ocean floor. This made it possible to obtain a real picture of the topography of the ocean floor. In the 1950s–70s. carried out complex geophysical. and geological. A.'s research about. and established the features of the relief of its bottom and tectonics, the structure of the sedimentary strata. Many large forms of bottom topography (submarine ridges, mountains, trenches, fault zones, vast basins and uplifts) have been identified, and geomorphological data have been compiled. and tectonic. cards. Unique results were obtained under the IODP International Deep Sea Ocean Drilling Program (1961–2015, ongoing).
The third stage of ocean research is mainly aimed at studying its role in the global processes of matter and energy transfer and its influence on climate formation. Complexity and wide range research work demanded extensive international cooperation. The Scientific Committee for Oceanic Research (SCOR), formed in 1957, the Intergovernmental Oceanographic Commission of UNESCO (IOC), which has been operating since 1960, and other international organizations play an important role in coordinating and organizing international research. In 1957-58, a lot of work was carried out within the framework of the first International Geophysical Year (IGY). Subsequently, major international projects were aimed both at the study of individual parts of the AO, for example, EQUALANT I–III (1963–64), Polygon-70 (1970), SICAR (1970–75), POLYMODE (1977–78 ), and A. o. as parts of the World Ocean, for example, TOGA (1985–89), GEOSECS (1973–74), WOCE (1990–96), and others. the role of the ocean in the global carbon cycle and more. other questions. In con. 1980s owls. deep-sea submersibles"World» unique ecosystems of geothermal regions of the ocean rift zone were studied. If in the beginning 80s it was ok. 20 international ocean research projects, then by the 21st century. St. 100. The largest programs:« International Geosphere-Biosphere Program» (since 1986, 77 countries participate), it includes projects« Dynamics of global ocean ecosystems» (GLOBES, 1995–2010), "Global flows of matter in the ocean» (JGOFS, 1988–2003), " Land-ocean interaction in the coastal zone» (LOICZ), Integral Marine Biogeochemistry and Ecosystem Research (IMBER), Coastal Land-Ocean Interaction (LOICZ, 1993–2015), Ocean Surface-Lower Atmosphere Interaction Study (SOLAS, 2004–15, ongoing) ,« World Climate Research Program» (WCRP, since 1980, 50 countries participate), International Study of Biogeochemical Cycles and Large Scale Distribution of Trace Elements and Their Isotopes in the Marine Environment (GEOTRACES, 2006–15, ongoing), and more. etc. The Global Ocean Observing System (GOOS) is being developed. One of the main projects of the WCRP was the program "Climate and Ocean: Unsteadiness, Predictability and Variability" (CLIVAR, since 1995), which was based on the results of TOGA and WOCE. Ros. For many years, scientists have been conducting expeditionary studies of exchange processes at the border of the A. O. and the Arctic Ocean, circulation in the Drake Passage, distribution of cold Antarctic waters along deep-sea faults. Operating since 2005 international program"ARGO", in which observations are carried out by autonomous sounding instruments throughout the World Ocean (including AO), and the results are transmitted via artificial earth satellites to data centers.
In November 2015, for the first time in the last 30 years, Ross made a voyage from Kronstadt to the shores of Antarctica. research vessel of the Baltic Fleet "Admiral Vladimirsky". It made a transition with a length of over 34 thousand sea. miles. Along the route, hydrographic, hydrological, hydrometeorological and radio navigation studies were carried out, information was collected to correct marine navigation charts, navigation manuals and manuals. Having rounded the southern tip of the African continent, the ship entered the marginal seas of Antarctica. He moored near the station "Progress", scientists exchanged with the staff of the station data on monitoring the ice conditions, the melting of the Arctic ice, the weather. The expedition ended on 15.4.2016. In addition to the crew, hydrographers of the 6th Atlantic oceanographic department took part in the expedition. hydrographic expeditions. services of the Baltic Fleet, employees of Ros. state hydrometeorological University, the Institute of the Arctic and Antarctic, etc. The work on the creation of the third part of the Oceanographic Atlas WOCE (The World Ocean Circulation Experiment), dedicated to the Atlantic Ocean, was completed, the presentation of which took place in February 2015 at the IO RAS named after A.I. P. P. Shirshova.
Economic use
A. o. occupies an important place in the world economy among other oceans of our planet. Man's use of the sea, as well as other seas and oceans, follows several basic principles. directions: transport and communications, fishing, mining. resources, energy, recreation.
Transport
Already within 5 centuries A. about. occupies a leading role in maritime transport. With the opening of the Suez (1869) and Panama (1914) canals, short sea routes appeared between the Atlantic, Indian and Pacific oceans. To the share of A. o. accounts for approx. 3/5 of the cargo turnover of world shipping, in con. 20th century up to 3.5 billion tons of cargo per year was transported through its waters (according to IOC). OK. 1/2 of the volume of traffic is oil, gas and oil products, followed by general cargo, then iron ore, grain, coal, bauxite and alumina. Ch. the direction of transportation is the North Atlantic, which runs between 35–40 ° N. sh. and 55–60° N. sh. Main shipping routes connect the port cities of Europe, the USA (New York, Philadelphia) and Canada (Montreal). This direction adjoins the sea routes of the Norwegian, Northern and int. seas of Europe (Baltic, Mediterranean and Black). Transported to the main raw materials (coal, ores, cotton, timber, etc.) and general cargo. Dr. important directions of transportation - South Atlantic: Europe - Central (Panama, etc.) and South America (Rio de Janeiro, Buenos Aires); East Atlantic: Europe - South Africa (Cape Town); west-Atlantic: Sev. America, South America is southern Africa. Before the reconstruction of the Suez Canal (1981) b. hours of oil tankers from the Indian basin approx. was forced to go around Africa.
The transportation of passengers occupies an important place in the A. about. since the 19th century, when mass emigration from the Old World to America began. The first steam-sailing vessel, the Savannah, crossed the A. O. for 29 days in 1819. At the beginning. 19th century The Blue Ribbon Prize was established for passenger ships that will cross the ocean the fastest. This prize was awarded, for example, to such famous liners as Lusitania (4 days and 11 hours), Normandy (4 days and 3 hours), Queen Mary (4 days without 3 minutes). The last time the "Blue Ribbon" was awarded to the Amer. liner "United States" in 1952 (3 days and 10 hours). In the beginning. 21st century the duration of a passenger liner flight between London and New York is 5–6 days. Max. passenger transportation through A. o. fell on 1956–57, when more than 1 million people were transported a year; The majority of passengers prefer air transport (the record flight time for the Concorde supersonic airliner on the New York-London route is 2 hours 54 minutes). The first non-stop flight through A. about. committed 14-15.6.1919 English. pilots J. Alcock and A. W. Brown (Newfoundland - Ireland), the first non-stop flight through the A. about. alone (from continent to continent) 20–21.5.1927 – Amer. pilot C. Lindberg (New York - Paris). In the beginning. 21st century practically the entire flow of passengers through A. o. served by aviation.
Connection
In 1858, when there was no radio communication between the continents, through A. o. The first telegraph cable was laid. To con. 19th century 14 telegraph cables connected Europe with America and 1 with Cuba. In 1956, the first telephone cable was laid between the continents, by the mid-1990s. at the bottom of the ocean, St. 10 telephone lines. In 1988, the first transatlantic fiber-optic communication line was laid, at the beginning of the 21st century. there are 8 lines.
Fishing
A. o. considered the most productive ocean, its biological. resources are exploited by man most intensively. In A. o. fishing and seafood production account for 40–45% of the total world catch (area approx. 25% of the world approx.). The majority of the catch (up to 70%) consists of herring fish (herring, sardines, etc.), cod fish (cod, haddock, hake, whiting, pollock, saffron cod, etc.), flounder, halibut, and sea bass. Production of shellfish (oysters, mussels, squids, etc.) and crustaceans (lobsters, crabs) approx. eight%. According to FAO estimates, the annual catch of fish products in the A. about. is 85–90 million tons, but for most of the fishing areas of the Atlantic, the fish catch reached in the middle. 1990s its maximum and its increase is undesirable. The traditional and most productive fishing area is the north-east. part of the Arctic Ocean, including the North and Baltic Seas (mainly herring, cod, flounder, sprats, and mackerel). In the north-west. area of the ocean, on the Newfoundland banks, cod, herring, flounder, squid, etc. have been harvested for many centuries. In the center. parts of A. o. there is a catch of sardine, horse mackerel, mackerel, tuna, etc. In the south, on the Patagono-Falkland shelf elongated along the latitude, fishing for both warm-water species (tuna, marlin, swordfish, sardines, etc.) and cold-water species (blue whiting, hake , notothenia, toothfish, etc.). Off the coast of and southwest. African catch of sardine, anchovy and hake. In the Antarctic area of the ocean, planktonic crustaceans (krill), marine mammals, from fish - notothenia, toothfish, silverfish, etc., are of commercial importance. 20th century in high-latitude sowing. and south. areas of the ocean were active fishing decomp. species of pinnipeds and cetaceans, but in recent decades it has declined sharply due to the depletion of biological. resources and thanks to environmental activities, including intergovernmental ones. agreements to limit their production.
Mineral resources
Miner is being developed more and more actively. wealth of the ocean floor. Deposits of oil and combustible gas have been studied more fully; belong to 1917, when oil production began in the industrial. scales in east. parts of the Maracaibo lagoon (Venezuela). Major centers offshore production: Venezuelan Bay, Maracaibo Lagoon ( Maracaiba oil and gas basin), Mexican Hall. ( Gulf of Mexico oil and gas basin), hall. Pariah ( Orinok oil and gas basin), Brazilian shelf (Sergipe-Alagoas oil and gas basin), Gulf of Guinea. ( Gulf of Guinea oil and gas basin), Northern m. ( North Sea oil and gas region), etc. Alluvial deposits of heavy minerals are widespread along many coasts. The largest development of alluvial deposits of ilmenite, monocyte, zircon, rutile are carried out off the coast of Florida. Similar deposits are located in the Gulf of Mexico, off the east. US coasts, as well as Brazil, Uruguay, Argentina and the Falkland Islands. On the shelf southwest. Africa is developing coastal marine diamond placers. Gold-bearing placers were found off the coast of Nova Scotia at depths of 25–45 m. In A. o. one of the world's largest iron ore deposits, Wabana, has been explored (in Conception Bay off the coast of Newfoundland), and iron ore is also mined off the coast of Finland, Norway, and France. In the coastal waters of Great Britain and Canada, coal deposits are being developed, it is mined in mines located on land, the horizontal workings of which go under the seabed. On the shelf of the Gulf of Mexico. large sulfur deposits are being developed Gulf of Mexico sulfur-bearing province. In the coastal zone of the ocean, sand is mined for construction and production of glass, gravel. On the shelf east. US coasts and west. coasts of Africa, phosphorite-bearing sediments have been explored, but their development is still unprofitable. The total mass of phosphorites on the continental shelf is estimated at 300 billion tons. Large fields of ferromanganese nodules have been found at the bottom of the North American Basin and on the Blake Plateau; are estimated at 45 billion tons.
Recreational resources
From the 2nd floor. 20th century The use of recreational resources of the ocean is of great importance for the economies of coastal countries. Old resorts are being developed and new ones are being built. Since the 1970s ocean liners are laid down, intended only for cruises, they are distinguished by their large size (displacement of 70 thousand tons or more), an increased level of comfort and relative slowness. Main cruise ship routes A. o. – The Mediterranean and Caribbean Seas and the Mexican Hall. From con. 20 - early. 21st century scientific-tourist and extreme cruise routes are developing, mainly in the high latitudes of the North. and Yuzh. hemispheres. In addition to the Mediterranean and Black Sea basins, the main resort centers are located in the Canary, Azores, Bermuda Islands, in the Caribbean and the Gulf of Mexico.
Energy
Energy sea tides A. o. is estimated at about 250 million kW. In the Middle Ages, tidal wave mills and sawmills were built in England and France. At the mouth of the river Rance (France) operates a tidal power plant. The use of the hydrothermal energy of the ocean (temperature difference in surface and deep waters) is also considered promising; a hydrothermal station operates on the coast of Côte d'Ivoire.
Port cities
On the banks of A. o. most of the world's major ports are located: in Western Europe - Rotterdam, Marseille, Antwerp, London, Liverpool, Genoa, Le Havre, Hamburg, Augusta, Southampton, Wilhelmshaven, Trieste, Dunkirk, Bremen, Venice, Gothenburg, Amsterdam, Naples, Nantes - St. Naser, Copenhagen; all in. America - New York, Houston, Philadelphia, Baltimore, Norfolk - Newport, Montreal, Boston, New Orleans; in Yuzh. America - Maracaibo, Rio de Janeiro, Santos, Buenos Aires; in Africa - Dakar, Abidjan, Cape Town. Ros. port cities do not have direct access to the sea. and are located on the banks int. the seas belonging to its basin: St. Petersburg, Kaliningrad, Baltiysk (Baltic Sea), Novorossiysk, Tuapse (Black Sea).
Many seas wash the shores of one or more countries. Some of these seas are huge, others are very small... Only the inland seas are not part of the ocean.
After the Earth formed from a bunch of gas and dust 4.5 billion years ago, the temperature on the planet dropped and the vapor contained in the atmosphere condensed (turned into liquid when cooled), settling on the surface in the form of rain. From this water, the world ocean was formed, subsequently divided by the continents into four oceans. These oceans include numerous coastal seas, often interconnected.
The largest seas of the Pacific Ocean
Philippine Sea
Area: 5.7 million km 2, located between Taiwan in the north, the Marianne Islands in the east, the Caroline Islands in the southeast and the Philippines in the west.
coral sea
Area: 4 million km 2, bounded in the west by Australia, Papua New Guinea in the north, Vanuatu in the east and New Caledonia
South China Sea
Area: 3.5 million km 2, located between the Philippines in the east, Malaysia in the south, Vietnam in the west and China in the north
tasman sea
Area: 3.3 million km 2, washes Australia in the west and New Zealand in the east and separates the Pacific and Indian oceans.
Bering Sea
Area: 2.3 million km 2, located between Chukotka (Russia) in the west and Alaska (USA) in the east.
Japanese Sea
Area: 970,000 km 2, located between the Russian Far East in the northwest, Korea in the west, and Japan in the east.
Major seas of the Atlantic Ocean
Sargasso Sea
Area: 4 million km 2, located between Florida (USA) in the west and the northern Antilles in the south.
Composition of sea water
Sea water is approximately 96% water and 4% salt. Apart from the Dead Sea, the most salty sea in the world is the Red Sea: it contains 44 grams of salt per liter of water (against 35 grams on average for most seas). Such a high salt content is due to the fact that in this hot region, water evaporates faster.
gulf of guinea
Area: 1.5 million km 2, located at the latitude of the Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Equatorial Guinea and Gabon.
Mediterranean Sea
Area: 2.5 million km 2, surrounded by Europe in the north, Western Asia in the east and North Africa on South.
Antilles Sea
Area: 2.5 million km 2, located between the Antilles in the east, the coast of South America in the South and Central America in the West.
Gulf of Mexico
Area: 1.5 million km 2, it is adjacent to the southern coast of the United States from the north and Mexico from the west.
Baltic Sea
Area: 372,730 km 2 , washes Russia and Finland in the north, Estonia, Latvia and Lithuania in the east, Poland and Germany in the south and Denmark with Sweden in the west.
North Sea
Area: 570,000 km2, bordered by Scandinavia to the east, Germany, the Netherlands, Belgium and France to the south, and Great Britain to the west.
Major seas of the Indian Ocean
Arabian Sea
Area: 3.5 million km 2, washes the Arabian Peninsula in the west, Pakistan in the north and India in the east.
bay of bengal
Area: 2.1 million km 2, located between the coasts of India in the west, Bangladesh in the north, Myanmar (Burma) in the northeast, the Andaman and Nicobar Islands in the southeast and Sri Lanka in the southwest.
Great Australian Bight (Australian Bight)
Area: 1.3 million km 2, extends along south coast Australia.
Arafura Sea
Area: 1 million km 2, located between Papua New Guinea in the northwest, Indonesia in the west and Australia in the south.
mozambique channel
Area: 1.4 million km 2, located near Africa, between the coasts of Mozambique in the west and Madagascar in the east.
The largest seas of the Arctic Ocean
Barents Sea
Area: 1.4 million km 2, washes the coast of Norway in the west and Russia in the east.
Greenland Sea
Area: 1.2 million km 2, bounded by Greenland in the west and the island of Svalbard (Norway) in the east.
East-Siberian Sea
Area: 900,000 km 2, washes the coast of Siberia.
The largest seas of Antarctica
inland seas
Inland, or closed, seas are completely surrounded by land. Black and Caspian Sea- the largest of them.
Black Sea
Area: 461,000 km2. It is surrounded by Romania and Bulgaria to the west, Russia and Ukraine to the north, Georgia to the east and Turkey to the south. It communicates with the Mediterranean Sea through the Sea of Marmara.
Bellingshausen Sea
Area: 1.2 million km 2, located near Antarctica.
Caspian Sea
Area: 376,000 km2, located between Azerbaijan in the west, Russia in the northwest, Kazakhstan in the north and east, Turkmenistan in the southeast and Iran in the south.
Ross Sea
Area: 960,000 km2, located north of Antarctica.
Weddell Sea
Area: 1.9 million km 2, located between the South Orkney Islands (UK) and the South Shetland Islands (UK) in the north and Antarctica in the south.
The Dead Sea is so salty that there are no living organisms in it.