Atlantic Ocean
Geographical location.The Atlantic Ocean stretches from north to south for 16 thousand km from subarctic to Antarctic latitudes. The ocean is wide in the northern and southern parts, narrowing in equatorial latitudes to 2900 km. In the north it communicates with the Arctic Ocean, and in the south it is widely connected with the Pacific and Indian Oceans. It is limited by the shores of North and South America in the west, Europe and Africa in the east, and Antarctica in the south.
The Atlantic Ocean is the second largest among the planet's oceans. The ocean coastline in the northern hemisphere is heavily dissected by numerous peninsulas and bays. There are many islands, internal and marginal seas near the continents. The Atlantic includes 13 seas, which occupy 11% of its area.
Bottom relief. Through the entire ocean (approximately at an equal distance from the coasts of the continents) passes Mid-Atlantic Ridge. The relative height of the ridge is about 2 km. Transverse faults divide it into separate segments. In the axial part of the ridge there is a giant rift valley ranging from 6 to 30 km wide and up to 2 km deep. Both underwater active volcanoes and the volcanoes of Iceland and the Azores are confined to the rift and faults of the Mid-Atlantic Ridge. On both sides of the ridge there are basins with a relatively flat bottom, separated by elevated rises. The shelf area in the Atlantic Ocean is larger than in the Pacific.
Mineral resources. Oil and gas reserves have been discovered on the North Sea shelf, in the Gulf of Mexico, Guinea and Biscay. Phosphorite deposits were discovered in the area of rising deep waters off the coast of North Africa in tropical latitudes. Placer deposits of tin off the coast of Great Britain and Florida, as well as diamond deposits off the coast of South-West Africa, have been identified on the shelf in sediments of ancient and modern rivers. Ferromanganese nodules were found in bottom basins off the coasts of Florida and Newfoundland.
Climate.The Atlantic Ocean is located in all climate zones of the Earth. The main part of the ocean is between 40° N latitude. and 42° S - is located in subtropical, tropical, subequatorial and equatorial climatic zones. There are high positive air temperatures here all year round. The most severe climate is found in sub-Antarctic and Antarctic latitudes, and to a lesser extent in subpolar and northern latitudes.
Currents.In the Atlantic, as in the Pacific, two rings of surface currents are formed. In the northern hemisphere, the Northern Trade Wind Current, Gulf Stream, North Atlantic and Canary Currents form a clockwise movement of water. In the southern hemisphere, the South Trade Wind, the Brazilian Current, the West Wind Current and the Benguela Current form the movement of water counterclockwise. Due to the considerable extent of the Atlantic Ocean from north to south, meridional water flows are more developed in it than latitudinal ones.
Properties of water. The zoning of water masses in the ocean is complicated by the influence of land and sea currents. This is manifested primarily in the temperature distribution of surface waters. In many areas of the ocean, isotherms off the coast deviate sharply from the latitudinal direction.
The northern half of the ocean is warmer than the southern half, the temperature difference reaches 6°C. The average surface water temperature (16.5°C) is slightly lower than in the Pacific Ocean. The cooling effect is exerted by the waters and ice of the Arctic and Antarctic. The salinity of surface waters in the Atlantic Ocean is high. One of the reasons for increased salinity is that a significant part of the moisture evaporating from the water area does not return to the ocean, but is transferred to neighboring continents (due to the relative narrowness of the ocean).
Many large rivers flow into the Atlantic Ocean and its seas: the Amazon, Congo, Mississippi, Nile, Danube, La Plata, etc.
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They carry huge masses of fresh water, suspended material and pollutants into the ocean. Ice forms in the desalinated bays and seas of subpolar and temperate latitudes in winter off the western shores of the ocean. Numerous icebergs and floating sea ice are disrupting shipping in the North Atlantic Ocean.
Organic world. The Atlantic Ocean is poorer in flora and fauna species than the Pacific Ocean. One of the reasons for this is its relative geological youth and noticeable cooling in the Quaternary period during the glaciation of the northern hemisphere. At the same time, in quantitative terms, the ocean is rich in organisms - it is the most productive per unit area. This is primarily due to the widespread development of shelves and shallow banks, which are home to many bottom and bottom fish (cod, flounder, perch, etc.). The biological resources of the Atlantic Ocean are depleted in many areas. The ocean's share of global fisheries has declined significantly in recent years.
Natural complexes.In the Atlantic Ocean, all zonal complexes are distinguished - natural zones, except for the North Polar. Water northern subpolar belt rich in life. It is especially developed on the shelves off the coasts of Iceland, Greenland and the Labrador Peninsula.
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Temperate zone Characterized by intense interaction of cold and warm waters, its waters are the most productive areas of the Atlantic. Vast expanses of warm waters of two subtropical, two tropical and equatorial zones less productive than the waters of the northern temperate zone.
In the northern subtropical zone it stands out special natural aquatic complex of the Sargasso Sea. It is worth saying that it is characterized by increased water salinity (up to 37.5 ppm) and low bioproductivity. Grow in clear water of pure blue color brown algae - sargassum, which gave the name to the water area.
In the temperate zone of the southern hemisphere, as in the north, natural complexes are rich in life in areas where waters with different temperatures and water densities mix. In the subantarctic and antarctic belts Characterized by the manifestation of seasonal and permanent ice phenomena, which affect the composition of the fauna (krill, cetaceans, notothenia fish).
Economic use. The Atlantic Ocean represents all types of human economic activity in marine areas. Among them, maritime transport is of greatest importance, followed by underwater oil and gas production, and only then by fishing and use of biological resources.
On the shores of the Atlantic there are more than 70 coastal countries with a population of over 1.3 billion people. Many transoceanic routes with large volumes of freight and passenger traffic pass through the ocean. The most significant ports in the world in terms of cargo turnover are located on the coasts of the ocean and its seas.
The already explored mineral resources of the ocean are significant (examples are given above). At the same time, oil and gas fields are currently being intensively developed on the shelf of the North and Caribbean Seas, in the Bay of Biscay. Many countries that previously did not have significant reserves of these types of mineral raw materials are now experiencing economic growth due to their production (England, Norway, the Netherlands, Mexico, etc.).
Biological resources oceans have been used intensively for a long time. At the same time, due to overfishing of a number of valuable commercial fish species, in recent years the Atlantic is inferior to the Pacific Ocean in the production of fish and seafood.
Intensive human economic activity in the Atlantic Ocean and its seas causes a noticeable deterioration of the natural environment - both in the ocean (water and air pollution, reduction in stocks of commercial fish species) and on the coasts. In particular, recreational conditions on the ocean shores are deteriorating. In order to prevent further and reduce existing pollution of the natural environment of the Atlantic Ocean, scientific recommendations are being developed and international agreements are being concluded on the rational use of ocean resources.
Atlantic Ocean - concept and types. Classification and features of the category "Atlantic Ocean" 2017, 2018.
The Atlantic Ocean provides 2/5 of the world's catch and its share has been decreasing over the years. In subantarctic and Antarctic waters, notothenia, blue whiting and others are of commercial importance, in the tropical zone - mackerel, tuna, sardine, in areas of cold currents - anchovies, in temperate latitudes of the northern hemisphere - herring, cod, haddock, halibut, sea bass. In the 1970s, due to overfishing of some fish species, fishing volumes declined sharply, but after the introduction of strict limits, fish stocks are gradually recovering. There are several international fisheries conventions in force in the Atlantic Ocean basin, which aim at the effective and rational use of biological resources, based on the application of scientifically based measures to regulate fishing. The Atlantic Ocean shelves are rich in oil and other mineral deposits. Thousands of wells have been drilled offshore the Gulf of Mexico and the North Sea. Phosphorite deposits were discovered in the area of rising deep waters off the coast of North Africa in tropical latitudes. Placer deposits of tin off the coast of Great Britain and Florida, as well as diamond deposits off the coast of South-West Africa, have been identified on the shelf in sediments of ancient and modern rivers. Ferromanganese nodules were found in bottom basins off the coasts of Florida and Newfoundland.
Due to the growth of cities, the development of shipping in many seas and in the ocean itself, a deterioration in natural conditions has recently been observed. The waters and air are polluted, and conditions for recreation on the shores of the ocean and its seas have deteriorated. For example, the North Sea is covered with many kilometers of oil slicks. Off the coast of North America, the oil film is hundreds of kilometers wide. The Mediterranean Sea is one of the most polluted on Earth. The Atlantic is no longer able to clean itself of waste on its own.
124.Physico-geographical zoning of the Atlantic Ocean. At the level of physical-geographical zones, the following divisions are distinguished: 1. Northern subpolar belt (northwest part of the ocean adjacent to Labrador and Greenland). Despite the low water and air temperatures, these areas are distinguished by their high productivity and have always had important commercial importance.2. Northern temperate zone (extends far beyond the Arctic Circle into the Arctic Ocean). The coastal regions of this belt have a particularly rich organic world and have long been famous for the productivity of fishing regions.3. Northern subtropical zone (narrow). It stands out primarily for its high salinity and high water temperature. Life here is much poorer than in higher latitudes. The commercial significance is small, except for the Mediterranean (the pearl of the entire belt =)4. Northern tropical zone. It is characterized by a rich organic world within the neritic zone of the Caribbean Sea and very sparse within the open water area.5. Equatorial belt. It is distinguished by the constancy of temperature conditions, the abundance of precipitation and the general richness of the organic world.6. The southern tropical, subtropical and temperate zones, generally similar to those of the same name in the northern hemisphere, only the boundaries of the southern tropical and southern subtropical pass in the western part of approx. to the south (the influence of the Brazilian Current), and in the east - to the north (the influence of the cold Benguela Current).7. Southern subpolar – important commercial value.8. South polar! (it is absent in the north), are distinguished by the most severe natural conditions, ice cover and are significantly less populated.
125.Geographical location, size, boundaries, configuration of the Pacific Ocean. Pacific, ocean - greatest Earth's ocean. It accounts for about half (49%) of the area and more than half (53%) of the volume of the waters of the World Ocean, and its surface area is equal to almost a third of the entire surface of the Earth as a whole. In terms of the number (about 10 thousand) and total area (more than 3.5 million km 2) of islands, it ranks first among the other oceans of the Earth. In the northwest and west the Pacific Ocean limited the shores of Eurasia and Australia, in the northeast and east - the shores of North and South America. The border with the Arctic Ocean is drawn through the Bering Strait along the Arctic Circle. The southern border of the Pacific Ocean (as well as the Atlantic and Indian) is considered to be the northern coast of Antarctica. When distinguishing the Southern (Antarctic) Ocean, its northern boundary is drawn along the waters of the World Ocean, depending on the change in the regime of surface waters from temperate latitudes to Antarctic latitudes. Square The Pacific Ocean from the Bering Strait to the shores of Antarctica is 178 million km 2, the volume of water is 710 million km 3. The boundaries with other oceans south of Australia and South America are also drawn conditionally along the water surface: with the Indian Ocean - from Cape South East Point at approximately 147° E, with the Atlantic Ocean - from Cape Horn to the Antarctic Peninsula. In addition to wide connections with other oceans in the south, there is communication between the Pacific and northern Indian Oceans through the interisland seas and the straits of the Sunda archipelago. Northern and western (Eurasian) shores of the Pacific Ocean dismembered seas (there are more than 20 of them), bays and straits separating large peninsulas, islands and entire archipelagos of continental and volcanic origin. The coasts of Eastern Australia, southern North America, and especially South America are generally straightforward and inaccessible from the ocean. With a huge surface area and linear dimensions (more than 19 thousand km from west to east and about 16 thousand km from north to south), the Pacific Ocean is characterized by weak development of the continental margins (only 10% of the bottom area) and a relatively small number of shelf seas. Within the intertropical space, the Pacific Ocean is characterized by clusters of volcanic and coral islands.
Climate and hydrological regime of the Atlantic Ocean. Hydrological resources.
Diversity climatic conditions on the surface of the Atlantic Ocean is determined by its large meridional extent and the circulation of air masses under the influence of four main atmospheric centers: the Greenland and Antarctic max., Icelandic and Antarctic minima. In addition, two anticyclones are constantly active in the subtropics: the Azores and the South Atlantic. They are separated by an equatorial region of low pressure. This distribution of pressure regions determines the system of prevailing winds in the Atlantic. The greatest influence on the temperature regime of the Atlantic Ocean is exerted not only by its large meridional extent, but also by water exchange with the Arctic Ocean, the Antarctic seas and the Mediterranean Sea. Tropical latitudes are characterized by tempera. - 20 °C. To the north and south of the tropics there are subtropical zones with more noticeable seasonal zones (from 10 °C in winter to 20 °C in summer). Tropical hurricanes are a frequent occurrence in the subtropical zone. In temperate latitudes, the average temperature of the warmest month is between 10-15 °C, and the coldest month is −10 °C. Precipitation is about 1000 mm.
Surface currents. Northern Trade Wind Current(t)>Antilles(t)>Mexico. Gulf>Florida(t)>Gulf Stream>North Atlantic(t)>Canary(x)>North Trade Wind Current(t) – northern gyre.
Southern trade wind>Guiana heat. (north) and Brazilian heat. (south)>current Western winds(x)>Bengela(x)>Southern trade winds – southern gyre.
There are several tiers in the Atlantic Ocean deep sea currents. A powerful countercurrent passes under the Gulf Stream, the main core of which lies at a depth of up to 3500 m, with a speed of 20 cm/s. The powerful deep Louisiana Current is observed in the eastern part of the Atlantic Ocean, formed by the bottom runoff of saltier and warmer Mediterranean waters through the Strait of Gibraltar.
The highest tide values are confined to the Atlantic Ocean, which are observed in the fiord bays of Canada (in Ungava Bay - 12.4 m, in Frobisher Bay - 16.6 m) and Great Britain (up to 14.4 m in Bristol Bay). The highest tide in the world is recorded in the Bay of Fundy, on the east coast of Canada, where the maximum tide reaches 15.6-18 m.
Salinity. The highest salinity of surface waters in the open ocean is observed in the subtropical zone (up to 37.25 ‰), and the maximum in the Mediterranean Sea is 39 ‰. In the equatorial zone, where the maximum amount of precipitation is recorded, salinity decreases to 34 ‰. A sharp desalination of water occurs in the estuary areas (for example, at the mouth of La Plata 18-19 ‰).
Ice formation. Ice formation in the Atlantic Ocean occurs in the Greenland and Baffin seas and Antarctic waters. The main source of icebergs in the South Atlantic is the Filchner Ice Shelf in the Weddell Sea. Floating ice in the northern hemisphere reaches 40°N in July.
Upwelling. Along the entire western coast of Africa there is a particularly powerful upwelling zone caused by wind driven water,<связан. с пассатной циркуляцией. Также это зоны у Зелёного мыса, у берегов Анголы и Конго. Эти области наиболее благоприятны для развития орг. мира.
The bottom flora of the northern part of the Atlantic is represented by brown (mainly fucoids, and in the subditorial zone - kelp and alaria) and red algae. In the tropical zone, green algae (caulerpa), red algae (calcareous lithothamnia) and brown algae (sargassum) predominate. In the southern hemisphere, bottom vegetation is mainly represented by kelp forests. There are 245 species of phytoplankton in the Atlantic Ocean: peridinea, coccolithophores, and diatoms. The latter have a clearly defined zonal distribution; the maximum number of them lives in the temperate latitudes of the northern and southern hemispheres. The population of diatoms is most dense in the zone of the Western Wind Current.
The distribution of the fauna of the Atlantic Ocean has a pronounced zonal character. In the subantarctic and antarctic In the waters, notothenia, blue whiting and others are of commercial importance. Benthos and plankton in the Atlantic are poor in both species and biomass. In the subantarctic zone and in the adjacent temperate zone, biomass reaches its maximum. The zooplankton is dominated by copepods and pteropods; the nekton is dominated by mammals such as whales (blue whale), pinnipeds, and their fish - nototheniids. In the tropical zone, zooplankton is represented by numerous species of foraminifera and pteropods, several species of radiolarians, copepods, larvae of mollusks and fish, as well as siphonophores, various jellyfish, large cephalopods (squid), and, among benthic forms, octopuses. Commercial fish are represented by mackerel, tuna, sardines, and in areas of cold currents - anchovies. To tropical and subtropical corals are confined to the zones. Temperate latitudes The northern hemisphere is characterized by abundant life with a relatively small diversity of species. Of the commercial fish, the most important are herring, cod, haddock, halibut, and sea bass. Foraminifera and copepods are the most characteristic of zooplankton. The greatest abundance of plankton is in the area of the Newfoundland Bank and the Norwegian Sea. The deep-sea fauna is represented by crustaceans, echinoderms, specific species of fish, sponges, and hydroids. Several species of endemic polychaetes, isopods, and holothurians have been found in the Puerto Rico Trench.
There are 4 biogeographical regions in the Atlantic Ocean: 1. Arctic; 2. North Atlantic; 3. Tropico-Atlantic; 4. Antarctic.
Biological resources. The Atlantic Ocean provides 2/5 of the world's catch and its share has been decreasing over the years. In subantarctic and Antarctic waters, notothenia, blue whiting and others are of commercial importance, in the tropical zone - mackerel, tuna, sardine, in areas of cold currents - anchovies, in temperate latitudes of the northern hemisphere - herring, cod, haddock, halibut, sea bass. In the 1970s, due to overfishing of some fish species, fishing volumes declined sharply, but after the introduction of strict limits, fish stocks are gradually recovering. There are several international fisheries conventions in force in the Atlantic Ocean basin, which aim at the effective and rational use of biological resources, based on the application of scientifically based measures to regulate fishing.
Oil and natural gas
The most important mineral resources of the Atlantic Ocean include oil and natural gas. Oil and gas-bearing shelves off the coast of North America include the shelves of the Labrador Sea, as well as the bays of Georges Bank, Nova Scotia and St. Lawrence.
On the eastern shelf of Canada, oil reserves amount to 2.5 billion tons, natural gas reserves - 3.3 trillion. cube m; on the continental slope and eastern shelf of the United States - up to 0.54 billion tons of oil and gas - 0.39 trillion. cube m. More than 280 deposits have been identified on the southern shelf of the United States, and more than 20 deposits off the coast of Mexico. More than 60% of all Venezuela's oil is produced in the Maracaibo Lagoon. The fields near the island of Trinidad in the Gulf of Paria are actively exploited.
Oil and gas bearing areas have been discovered on the shelves of the Gulf of Sao Jorge (Argentina) and the Gulf of Toduz-os-Santos (Brazil). The total reserves of the Caribbean Sea shelves are up to 13 billion tons of oil and 8.5 trillion. cube m of natural gas. Oil fields have been discovered in the Irish and North (114 fields) seas, the Gulf of Guinea (on the Nigerian shelf - 50, off Gabon - 37, off Congo - 3, etc.). On the Mediterranean shelf, the forecast oil reserves are 110-120 billion tons. There are deposits in the Adriatic, Aegean, Ionian seas, off the coasts of Egypt, Tunisia, Spain, etc.
Oil and gas basins
The largest oil and gas basins in the Atlantic Ocean include:
- Gulf of Mexico oil and gas basin;
- Maracaiba oil and gas basin.
The oil and gas basin of the Gulf of Mexico is located in the waters of the Gulf and adjacent territories of Mexico, the USA, Cuba, Belize, and Guatemala. The total area of the oil and gas basin is about 2.5 million square meters. km. The initial industrial reserves of oil and condensate (data for 1985) are 18.3 billion tons and natural gas - 14.6 trillion. cube m.
The first deposits on the mainland part of the basin were discovered in 1896 (USA), and on the shelf - in 1938 (USA). In the American part of the basin, the largest deposits were discovered in the 30s. (Agua Dals-Stratton, East Texas, Carthage, Caillou Island, Old Ocean), and in the Mexican part - in the 70s. (Iris-Giraldas, Bermudez, Cantarel).
Note 1
In total, more than 5 thousand oil and 4 thousand gas and gas condensate fields have been discovered in the oil and gas basin of the Gulf of Mexico. 95% of deposits are in the USA.
Gulf of Mexico oil and gas basin confined to the southern regions of the Atlantic Epihercynian platform, represented by the Gulf of Mexico basin and the Gulf Coast. The basin is formed by sedimentary rocks of the Mesozoic-Cenozoic period with a maximum thickness of 15 km. The entire section of the sedimentary cover is associated with oil and gas content.
The furthest offshore deposit was identified at a distance of 240 km from the coast of Louisiana. Individual exploration wells are located at a distance of 260 km at a depth of 600 m. The oil in the outer zone is low-sulfur and light. Sulfur content increases in deposits that are associated with caprocks of salt domes. In the interior regions of the basin, oils are of medium density, methane-naphthenic composition and high-sulfur.
Natural gases contain a small amount of heavy homologues of methane and a lot of gas condensate. The main centers of natural gas production are Texas, Louisiana, Bay of Campeche, and the Reforma region.
On the territory of the Mexican oil and gas basin there is an extensive network of oil and gas pipelines, 75 oil refineries and 400 gas processing plants.
Maracaiba oil and gas basin is located in the northeast of Colombia, northwest of Venezuela, occupies the Gulf of Venezuela and the adjacent part of the landmass, Lake Maracaibo. The pool area is 86 thousand square meters. km, including about 30 thousand sq. km. water areas. The basin is surrounded by individual spurs of the Andes mountain system. The development of oil fields began in 1917. In total, 79 oil fields and 4 gas fields were discovered.
Initial oil reserves were 6.6 billion tons, natural gas - 1.7 trillion. cube m., on the shelf 5 billion tons and 1.2 trillion. cube m. respectively.
The Bolivar coastal-offshore oil and gas accumulation zone, stretching over 3.5 thousand square meters, stands out separately. km. Bolivar unites 8 deposits. The largest oil field is Lama, containing 584 million tons. Potential oil resources are estimated at 9.3 billion tons, natural gas - 1.9 trillion. cube m.
The Maracaiba oil and gas basin is formed mainly by terrigenous deposits of the Mesozoic and Cenozoic. The maximum thickness is 11 km. The reservoirs are sandstones and fractured limestones. A characteristic feature of the basin is its predominant oil content. Gas reserves represent 90% dissolved gas from oil fields. Oils are mainly viscous and heavy. Lighter oils belong to the Cretaceous deposits. The dissolved gas of the Bolivar zone contains heavy homologues of methane and fatty.
The main oil and gas processing centers are located in Punta Cardon and Amuay.
Minerals
The following minerals are mined on continental shelves:
- sulfur (Gulf of Mexico);
- iron ore (near the island of Newfoundland);
- diamonds (continental shelf of South America);
- phosphate sands and phosphorite formations (near Liberia, Morocco, Blake Plateau);
- hard coal (Canada, UK).
Coastal areas are rich in zirconium, titanium, monazite, phosphorites, and amber. The largest deposits are located off the coast of the Florida Peninsula and near Brazil. These minerals were found in smaller quantities off the coast of Uruguay, Argentina, Spain, Denmark, and Portugal.
Ferrous and tin-bearing sands are common on the Atlantic coast of Europe and North America, and deposits of gold, platinum and diamonds are found off the coast of southwestern Africa (Namibia, Angola, South Africa).
Note 2
The extraction of phosphorites and phosphate sand is unprofitable due to their lower quality compared to terrestrial fossils.
In the northwestern regions of the ocean, on the Blake Plateau and in the North American Basin, there are extensive fields of ferromanganese nodules. Their total reserves are estimated at 45 billion tons. They contain a high concentration of non-ferrous metals.
Barite, pebbles, sand, and limestone are mined from the seabed. Atlantic countries extract magnesium, table salt, bromine, and magnesium from sea water (Great Britain, France, Italy, Spain, Argentina, Canada).
South Atlantic Ocean. This includes areas adjacent to the east coast of South America and the southwest coast of Africa, as well as the Antarctic regions, with a total area
more than 40 million km 2 , of which only about 3 million km 2 (7.5%)
occupied by depths of less than 1000 m, and the largest shallow water plateau (about 1.4 million km 2) called the Patagonian-Falkland shelf, adjacent to the Atlantic coast of Uruguay and Argentina. The large latitudinal extent, which includes both warm subtropical and cold Antarctic zones, leaves its mark on the commercial fauna, represented here by both warm water (tuna, marlin, swordfish, scienes, sardines, etc.) and cold water (blue whiting, merluea, notothenia, silverfish, toothfish, etc.) inhabitants. The intensity of fishing here is quite high only on the southwestern and southern coasts of Africa, where in some years (1968-1970) sardines (up to 1.7 million tons), anchovies (0.4-0.6 million tons) and hake (0.5-0.7 million tons), while on the Patagonian shelf, the raw materials of which make it possible to produce at least 5-6 million tons of fish, the fishery is extremely poorly developed (only about 1.0 million tons). The total catch within the South Atlantic in recent years alone has reached 4 million tons, while the possible catch exceeds 10 million tons.
The Antarctic regions are of significant importance for fishing, where whales, seals, some fish, squid live in commercial quantities, and the resource of the abundant planktonic crustacean, Arctic krill, has a particularly great potential commercial importance.
Summarizing the current assessment of the used biological resources in the Atlantic Ocean and the possible prospects for the further development of fisheries, it should be considered that in this basin the catch of traditional fisheries by all countries can be increased from 23 - 25 to 35 million tons
The Soviet Union produced 3.5 million tons in the Atlantic Ocean basin, i.e. a significant portion (39%) of its marine fish catches, and in recent years Russia has been eyeing this vast region
as the most important for the implementation of sea and ocean fishing,
Lecture No. 9 Topic: "Raw materials of the Pacific Ocean."
Pacific Ocean. The Pacific Ocean basin makes up half
(176.7 million km 2 - 49.8%) of the entire water area of the World Ocean. The predominant part of its surface (80.8%) is located above depths from
3000 to 6000 m and only 8.7% (15.5 million km 2) is occupied by relatively shallow depths (less than 1000 m) and in this respect it is significantly inferior to the Atlantic, where about 15% is in shallow areas.
The greatest ruggedness of the coastline and the largest sections of the shelf are characteristic of the northern and western parts of the ocean (4.5 million km 2), where the Bering, Okhotsk, Japanese, Yellow, East and South China seas, etc. are located, as well as areas adjacent to the Indonesian archipelago. In addition, the shelf zones of Australia, New Zealand and Tasmania are quite extensive (more than 2 million km 2). Along the Pacific coast of North and esp. but the South American shelf is poorly developed. The oceanological regime of the Pacific Ocean is significantly influenced by a system of currents that creates several large-scale frontal zones and gyres in the northern and southern parts of the ocean.
Unlike the Atlantic, the northern part of the Pacific is connected to the Arctic Ocean basin by the narrow and shallow Bering Strait, and Pacific waters cannot warm the seas of the corresponding sector of the Arctic (East Siberian, Chukotka, etc.), which are characterized as low-productive. Here, only cod (polar cod) can be considered as a relatively abundant commercial fish.
The Pacific Ocean basin provides more than 53 million tons (6%) of global marine production. However, the relatively weak development of shallow waters leads to the fact that the catches here are sharply dominated by pelagic (89^) rather than bottom-dwelling objects, while in the Atlantic Ocean basin the share of the latter is much higher. Its modern fish productivity (300 kg/km) exceeded that of the Atlantic Ocean (250 kg/km) and many times
higher than the Indian one (60 kg/km), and there are still opportunities for further development of fishing for traditional objects within its boundaries.
