The Pacific Ocean is the largest of the oceans. Its area is 178.7 million km 2. The ocean surpasses in area all the continents combined, and has a rounded configuration: it is noticeably elongated from the northwest to the southeast, therefore air and water masses reach the greatest development here in the vast northwestern and southeastern water areas. The length of the ocean from north to south is about 16 thousand km, from west to east - more than 19 thousand km. It reaches its maximum width in the equatorial-tropical latitudes, so it is the warmest of the oceans. The volume of water is 710.4 million km 3 (53% of the water volume of the World Ocean). The average depth of the ocean is 3980 m, the maximum is 11,022 m (Marian Trench).
The ocean washes with its waters the shores of almost all continents except Africa. It reaches Antarctica on a broad front, and its cooling influence extends through the waters far to the north. On the contrary, Quiet is protected from cold air masses by considerable isolation (the close location of Chukotka and Alaska with a narrow strait between them). In this regard, the northern half of the ocean is warmer than the southern. The Pacific Ocean basin is connected to all other oceans. The boundaries between them are rather arbitrary. The most reasonable border with the Arctic Ocean: it runs along the underwater rapids of the narrow (86 km) Bering Strait somewhat south of the Arctic Circle. The border with the Atlantic Ocean runs along the wide Drake Passage (along the line Cape Horn in the archipelago - Cape Sternek on the Antarctic Peninsula). The border with the Indian Ocean is conditional.
Usually it is carried out as follows: the Malay Archipelago belongs to the Pacific Ocean, and between Australia and Antarctica the oceans delimit along the meridian of the South Cape (Tasmania Island, 147 ° E). The official boundary with the Southern Ocean ranges from 36° S. sh. off the coast of South America to 48 ° S. sh. (at 175°W). The outlines of the coastline are rather simple on the eastern margin of the ocean and very complex on the western margin, where the ocean occupies a complex of marginal and interisland seas, island arcs, and deep-water trenches. This is a vast region of the largest horizontal and vertical dissection of the earth's crust on Earth. The marginal type includes seas off the coast of Eurasia and Australia. Most of the inter-island seas are located in the area of the Malay Archipelago. They are often combined under the general name of the Australo-Asiatic. The seas are separated from the open ocean by numerous groups of islands and peninsulas. Island arcs are usually accompanied by deep-sea trenches, the number and depth of which is unparalleled in the Pacific Ocean. The coasts of North and South America are slightly indented, there are no marginal seas and such large clusters of islands. Deep-sea trenches are located directly off the coasts of the continents. Off the coast of Antarctica in the Pacific sector there are three large marginal seas: Ross, Amundsen and Bellingshausen.
The margins of the ocean, together with the adjacent parts of the continents, are included in the Pacific mobile belt ("ring of fire"), which is characterized by powerful manifestations of modern volcanism and seismic activity.
The islands of the central and southwestern parts of the ocean are united under the general name Oceania.
Its unique records are associated with the huge size of the Pacific Ocean: it is the deepest, the warmest on the surface, the highest wind waves are formed here, the most destructive tropical hurricanes and tsunamis, etc. The position of the ocean in all latitudes determines the exceptional diversity of its natural conditions and resources .
Occupying about 1/3 of the surface of our planet and almost 1/2 of the area, the Pacific Ocean is not only a unique geophysical object of the Earth, but also largest region multilateral economic activity and diverse interests of mankind. Since ancient times, the inhabitants of the Pacific shores and islands have mastered the biological resources of coastal waters and made short voyages. Over time, other resources began to be involved in the economy, their use gained a wide industrial scope. Today, the Pacific Ocean plays a very important role in the life of many countries and peoples, which is largely determined by its natural conditions, economic and political factors.
Features of the economic and geographical position of the Pacific Ocean
In the north, vast expanses of the Pacific Ocean through the Bering Strait are connected to the Arctic Ocean.
The border between them runs along a conditional line: Cape Unikyn (Chukotka Peninsula) - Shishmareva Bay (Seward Peninsula). In the west, the Pacific Ocean is bounded by the Asian mainland, in the southwest by the shores of the islands of Sumatra, Java, Timor, then by the east coast of Australia and a conditional line crossing the Bass Strait and then following along the coast of Tasmania, and to the south along the ridge of underwater rises to Cape Alden on Wilkes Land in . The eastern limits of the ocean are the shores of North and South America, and to the south - a conditional line from the island of Tierra del Fuego to the Antarctic Peninsula on the mainland of the same name. In the extreme South, the waters of the Pacific Ocean wash Antarctica. Within these limits, it occupies an area of 179.7 million km2, including marginal seas.
The ocean has a spherical shape, especially pronounced in the northern and eastern parts. Its greatest extent in latitude (about 10,500 miles) is noted along the parallel of 10°N, and the greatest length (about 8,500 miles) falls on the meridian of 170°W. Such great distances between the northern and southern, western and eastern shores are an essential natural feature of this ocean.
The coastline of the ocean is strongly indented in the west, in the east the coasts are mountainous and poorly dissected. In the north, west and south of the ocean are large seas: Bering, Okhotsk, Japanese, Yellow, East China, South China, Sulawesi, Javanese, Ross, Amundsen, Bellingshausen, etc.
The bottom relief of the Pacific Ocean is complex and uneven. In most of the transition zone, the shelves do not have significant development. For example, off the American coast, the width of the shelf does not exceed several tens of kilometers, but in the Bering, East China, and South China seas it reaches 700-800 km. In general, the shelves occupy about 17% of the entire transition zone. Continental slopes are steep, often stepped, dissected by submarine canyons. The ocean bed occupies a huge space. By a system of large uplifts, ridges and individual mountains, wide and relatively low swells, it is divided into large basins: Northeast, Northwest, East Mariana, West Caroline, Central, South, etc. The most significant East Pacific uplift is included in world system of mid-ocean ridges. In addition to it, large ridges are common in the ocean: Hawaiian, Imperial Mountains, Carolina, Shatsky, etc. A characteristic feature of the topography of the ocean floor is the confinement of the greatest depths to its periphery, where deep-sea trenches are located, most of which are concentrated in the western part of the ocean - from the Gulf of Alaska to New Zealand.
The vast expanses of the Pacific Ocean cover all natural belts from the northern subpolar to the southern polar, which is the reason for the diversity of its climatic conditions. At the same time, the most significant part of the ocean space, located between 40 ° N. sh. and 42 ° S, is located within the equatorial, tropical and subtropical zones. The southern marginal part of the ocean is climatically more severe than the northern one. Due to the cooling influence of the Asian continent and the predominance of west-east transport, typhoons are characteristic of temperate and subtropical latitudes of the western part of the ocean, especially frequent in June-September. The northwestern part of the ocean is characterized by monsoons.
Exceptional dimensions, peculiar outlines, large-scale atmospheric processes largely determine the features of the hydrological conditions of the Pacific Ocean. Since a fairly significant part of its area is located in equatorial and tropical latitudes, and the connection with the Arctic Ocean is very limited, since the water on the surface is higher than in other oceans and is equal to 19’37 °. The predominance of precipitation over evaporation and a large river runoff cause a lower salinity of surface waters than in other oceans, the average value of which is 34.58% o.
The temperature and salinity on the surface vary both by water area and by season. The most noticeable seasonal changes in temperature in the western part of the ocean. Seasonal fluctuations in salinity are generally small. Vertical changes in temperature and salinity are observed mainly in the upper 200-400 m layer. At great depths they are insignificant.
The general circulation in the ocean consists of horizontal and vertical movements of water, which are traced to some extent from the surface to the bottom. Under the influence of large-scale atmospheric circulation over the ocean, surface currents form anticyclonic gyres in subtropical and tropical latitudes and cyclonic gyres in northern temperate and southern high latitudes. The ring-shaped movement of surface waters in the northern part of the ocean is formed by the North trade wind, Kuroshio, North Pacific warm currents, California, Kuril cold and Alaska warm. The system of circular currents in the southern regions of the ocean includes the warm South Trade Winds, the East Australian, the zonal South Pacific, and the cold Peruvian. The rings of currents of the northern and southern hemispheres during the year separate the Inter-trade current, passing north of the equator, in the band between 2-4 ° and 8-12 ° N. latitude. The speeds of surface currents are different in different regions of the ocean and change with the seasons. Vertical water movements of different mechanism and intensity are developed throughout the ocean. Density mixing takes place in the surface horizons, which is especially significant in areas of ice formation. In areas of convergence of surface currents, surface waters sink and underlying waters rise. The interaction of surface currents and vertical movements of water is one of critical factors formation of the structure of waters and water masses of the Pacific Ocean.
In addition to these main natural features, the economic development of the ocean is strongly influenced by social and economic conditions characterized by the EGP of the Pacific Ocean. In relation to the land spaces gravitating towards the ocean, the EGP has its own distinctive features. The Pacific Ocean and its seas wash the coasts of three continents, on which there are more than 30 coastal states with general population about 2 billion people, i.e. about half of humanity lives here.
Countries - Russia, China, Vietnam, USA, Canada, Japan, Australia, Colombia, Ecuador, Peru, etc. - go to the Pacific Ocean. Each of the three main groups of Pacific states includes countries and their regions with a more or less high level of economic development . This affects the nature and possibilities of using the ocean.
The length of the Pacific coast of Russia is more than three times the length of the coastline of our Atlantic seas. In addition, unlike the western ones, the Far Eastern sea coasts form a continuous front, which facilitates economic maneuvering in its individual sections. However, the Pacific Ocean is far from the main economic centers and densely populated areas of the country. This remoteness seems to be decreasing as a result of the development of industry and transport in the eastern regions, but nevertheless it significantly affects the nature of our relations with this ocean.
Almost all mainland states and many island states, with the exception of Japan, adjacent to the Pacific basin, have large reserves of diverse natural resources that are being intensively developed. Consequently, the sources of raw materials are distributed relatively evenly along the periphery of the Pacific Ocean, and the centers of its processing and consumption are located mainly in the northern part of the ocean: in the USA, Japan, Canada and, to a lesser extent, in Australia. The uniform distribution of natural resources along the coast of the ocean and the confinement of their consumption to certain centers is a characteristic feature of the EGP of the Pacific Ocean.
Continents and partially islands in vast spaces separate the Pacific Ocean from other oceans by natural boundaries. Only to the south of Australia and New Zealand are the Pacific waters connected by a wide front to the waters of the Indian Ocean, and through the Strait of Magellan and the Drake Strait - to the waters of the Atlantic. In the north, the Pacific Ocean is connected to the Arctic Ocean by the Bering Strait. In general, the Pacific Ocean, excluding its sub-Antarctic regions, is connected to other oceans in a relatively small part. Ways, its communications with the Indian Ocean pass through the Australo-Asian seas and their straits, and with the Atlantic - through the Panama Canal and the Strait of Magellan. The narrowness of the straits of the seas of Southeast Asia, the limited capacity of the Panama Canal, the remoteness from major world centers of the vast expanses of Antarctic waters reduce the transport capabilities of the Pacific Ocean. This is an important feature of his EGP in relation to the world's sea routes.
The history of the formation and development of the basin
The pre-Mesozoic stage of the development of the World Ocean is largely based on assumptions, and many questions about its evolution remain unclear. Regarding the Pacific Ocean, there is a lot of indirect evidence indicating that the Paleo-Pacific Ocean has existed since the middle of the Precambrian. It washed the only continent of the Earth - Pangea-1. It is believed that direct evidence of the antiquity of the Pacific Ocean, despite the youth of its modern crust (160-180 million years), is the presence of ophiolite rock associations in folded systems found throughout the continental periphery of the ocean and having an age up to the Late Cambrian. The history of ocean development in the Mesozoic and Cenozoic times has been more or less authentically reconstructed.
The Mesozoic stage, apparently, played a large role in the evolution of the Pacific Ocean. The main event of the stage is the collapse of Pangea II. In the Late Jurassic (160-140 million years ago), the opening of the young Indian and Atlantic Oceans took place. The growth of their bed (spreading) was compensated by the reduction in the area of the Pacific Ocean and the gradual closure of the Tethys. The ancient oceanic crust of the Pacific Ocean sank into the mantle (subduction) in the Zavaritsky-Benioff zones, which bordered the ocean, as at the present time, with an almost continuous strip. At this stage in the development of the Pacific Ocean, its ancient mid-ocean ridges were restructured.
The formation in the Late Mesozoic of folded structures in northeast Asia and Alaska separated the Pacific Ocean from the Arctic Ocean. In the east, the development of the Andean belt swallowed up the island arcs.
Cenozoic stage
The Pacific Ocean continued to shrink due to the thrust of the continents on it. As a result of the continuous movement of America to the west and the absorption of the ocean floor, the system of its median ridges turned out to be significantly shifted to the east and southeast, and even partially submerged under the continent of North America in the Gulf of California. The marginal seas of the northwestern water area also formed, and the island arcs of this part of the ocean acquired their modern form. In the north, during the formation of the Aleutian island arc, the Bering Sea split off, the Bering Strait opened up, and the cold waters of the Arctic Ocean began to flow into the Pacific Ocean. The basins of the Ross, Bellingshausen and Amundsen seas formed off the coast of Antarctica. There was a major fragmentation of the land that connected Asia and Australia, with the formation of numerous islands and seas of the Malay Archipelago. The marginal seas and islands of the transitional zone to the east of Australia acquired a modern look. An isthmus between the Americas formed 40-30 million years ago, and the connection between the Pacific Ocean and the Atlantic Ocean in the Caribbean region was finally interrupted.
Over the past 1-2 million years, the size of the Pacific Ocean has decreased very slightly.
The main features of the bottom topography
As in other oceans, all the main planetary morphostructural zones are clearly distinguished in the Pacific: the underwater margins of the continents, transitional zones, the ocean floor, and mid-ocean ridges. But the general plan of the bottom topography, the ratio of areas and the location of these zones, despite a certain similarity with other parts of the World Ocean, are distinguished by great originality.
The underwater margins of the continents occupy about 10% of the area of the Pacific Ocean, which is much less in comparison with other oceans. The continental shelf (shelf) accounts for 5.4%.
The shelf, like the entire underwater margin of the continents, reaches its greatest development in the western (Asiatic-Australian) coastal sector, in the marginal seas - the Bering, Okhotsk, Yellow, East China, South China, seas of the Malay Archipelago, as well as to the north and east from Australia. The shelf is wide in the northern part of the Bering Sea, where there are flooded river valleys and traces of relict glacial activity. In the Sea of Okhotsk, a submerged shelf (1000-1500 m deep) is developed.
The continental slope is also wide, with signs of fault-block dissection, cut by large underwater canyons. The continental foot is a narrow plume of accumulation of the products of the removal of turbidity flows and landslide masses.
To the north of Australia is a vast continental shelf with the widespread development of coral reefs. In the western part of the Coral Sea there is a unique structure of the Earth - the Great Barrier Reef. This is a discontinuous strip of coral reefs and islands, shallow bays and straits, stretching in the meridional direction for almost 2500 km, in the northern part the width is about 2 km, in the southern part up to 150 km. The total area is more than 200 thousand km 2. At the base of the reef lies a thick layer (up to 1000-1200 m) of dead coral limestone, accumulated under conditions of slow subsidence of the earth's crust in this area. To the west, the Great Barrier Reef descends gently and is separated from the mainland by a vast shallow lagoon - a strait up to 200 km wide and no more than 50 m deep. In the east, the reef breaks off to the mainland slope with an almost sheer wall.
A peculiar structure is the underwater margin of New Zealand. The New Zealand Plateau consists of two flat-topped uplifts: Campbell and Chatham separated by a depression. The underwater plateau is 10 times the area of the islands themselves. This is a huge block of the earth's crust of the continental type, with an area of about 4 million km 2, not associated with any of the nearest Continents. From almost all sides, the plateau is bounded by a continental slope, which passes into the foot. This peculiar structure, called the New Zealand microcontinent, has existed since at least the Paleozoic.
The underwater margin of North America is represented by a narrow strip of leveled shelf. The continental slope is heavily indented by numerous underwater canyons.
A peculiar area of the underwater margin, located to the west of California and called the California borderland. The bottom relief here is large boulders, characterized by a combination of underwater heights - horsts and depressions - grabens, the depths of which reach 2500 m. The nature of the relief of the borderland is similar to the relief of the adjacent land area. It is believed that this is a part of the continental shelf that is highly fragmented and submerged to different depths.
The underwater margin of Central and South America is distinguished by a very narrow shelf just a few kilometers wide. For a long distance, the role of the continental slope here is played by the near-continental wall of deep-water trenches. The continental foot is practically not expressed.
A significant part of the continental shelf of Antarctica is covered by ice shelves. The continental slope here is distinguished by its large width and dissection by submarine canyons. The transition to the ocean floor is characterized by weak manifestations of seismicity and modern volcanism.
transition zones
These morphostructures within the Pacific Ocean occupy 13.5% of its area. They are extremely diverse in their structure and are most fully expressed in comparison with other oceans. This is a natural combination of marginal sea basins, island arcs, and deep-water trenches.
In the Western Pacific (Asiatic-Australian) sector, a number of transitional regions are usually distinguished, replacing one another mainly in the submeridional direction. Each of them is different in its structure, and perhaps they are at different stages of development. The Indonesian-Philippines region is complexly built, including the South China Sea, the seas and island arcs of the Malay Archipelago and deep-water trenches, which are located here in several rows. To the northeast and east of New Guinea and Australia is also the complex Melanesian region, in which island arcs, basins, and trenches are located in several echelons. To the north of the Solomon Islands there is a narrow depression with depths up to 4000 m, on the eastern extension of which the Vityaz trench (6150 m) is located. OK. Leontiev identified this area as a special type of transition zone - Vityazevsky. A feature of this area is the presence of a deep-water trench, but the absence of an island arc along it.
In the transitional zone of the American sector, there are no marginal seas, no island arcs, and there are only deep-water troughs of the Central American (6662 m), Peruvian (6601 m) and Chilean (8180 m). Island arcs in this zone are replaced by young folded mountains of Central and South America, where active volcanism is concentrated. In the gutters, there is a very high density of earthquake epicenters with a magnitude of up to 7-9 points.
The transitional zones of the Pacific Ocean are areas of the most significant vertical dissection of the earth's crust on Earth: the excess of the Mariana Islands over the bottom of the trench of the same name is 11,500 m, and the South American Andes over the Peru-Chile Trench - 14,750 m.
Mid-ocean ridges (uplifts). They occupy 11% of the Pacific Ocean and are represented by the South Pacific and East Pacific Rise. The mid-ocean ridges of the Pacific Ocean differ in their structure and location from similar structures in the Atlantic and Indian Oceans. They do not occupy a middle position and are significantly shifted to the east and southeast. Such an asymmetry of the modern spreading axis in the Pacific Ocean is often explained by the fact that it is in the stage of a gradually closing oceanic basin, when the rift axis shifts to one of its edges.
The structure of the mid-ocean rises of the Pacific Ocean also has its own characteristics. These structures are characterized by a vault-like profile, a considerable width (up to 2000 km), a discontinuous strip of axial rift valleys with a wide participation of transverse fault zones in the formation of the relief. Subparallel transform faults cut the East Pacific Rise into separate blocks shifted relative to each other. The entire uplift consists of a series of gently sloping domes, with the spreading center confined to the middle part of the dome, approximately equal distances from the faults that bound it from the north and south. Each of these domes is also dissected by echelon-shaped short faults. Large transverse faults cross the East Pacific Rise every 200-300 km. The length of many transform faults exceeds 1500-2000 km. Often they not only cross the flank uplift zones, but also go far on the ocean floor. Among the largest structures of this type are Mendocino, Murray, Clarion, Clipperton, Galapagos, Easter, Eltanin and others. the system of the axial zone of the mid-ocean rises of the Pacific Ocean is less pronounced than in the Mid-Atlantic and other ridges of this type.
North of the equator, the East Pacific Rise narrows. The rift zone is clearly expressed here. In the California region, this structure invades the North American mainland. This is associated with the breakaway of the California Peninsula, the formation of a large active San Andreas fault and a number of other faults and depressions within the Cordillera. The formation of the Californian borderland is probably connected with the same.
The absolute marks of the bottom topography in the axial part of the East Pacific Rise are everywhere about 2500–3000 m, but at some elevations they decrease to 1000–1500 m. On the highest parts of the uplift are about. Easter and the Galapagos Islands. Thus, the amplitude of uplift above the surrounding basins is generally very large.
The South Pacific Rise, separated from the East Pacific Rise by the Eltanin Fault, is very similar to it in its structure. The length of the Eastern uplift is 7600 km, the Southern one is 4100 km.
Ocean bed
It occupies 65.5% of the total area of the Pacific Ocean. Mid-ocean rises divide it into two parts, differing not only in their size, but also in the features of the bottom topography. The eastern (more precisely, southeastern) part, which occupies 1/5 of the ocean floor, is shallower and less complex in comparison with the vast western part.
A large part of the eastern sector is occupied by morphostructures that are directly related to the East Pacific Rise. Here are its lateral branches - the Galapagos and Chilean uplifts. The large blocky ridges of Tehuantepec, Kokosovy, Carnegie, Noska, Sala y Gomez are confined to the transform fault zones that cross the East Pacific Rise. Submarine ridges divide eastern part ocean floor into a number of basins: Guatemala (4199 m), Panama (4233 m), Peru (5660 m), Chile (5021 m). The Bellingshausen Basin (6063 m) is located in the extreme southeastern part of the ocean.
The vast western part of the Pacific Ocean bed is characterized by a significant complexity of structure and a variety of landforms. Almost all morphological types of underwater uplifts of the bed are located here: arched shafts, blocky mountains, volcanic ridges, marginal uplifts, individual mountains (guyots).
Arched uplifts of the bottom are wide (several hundreds of kilometers) linearly oriented swellings of the basalt crust with an excess of 1.5 to 4 km above the adjacent basins. Each of them is, as it were, a gigantic shaft, cut by faults into a series of blocks. Usually, entire volcanic ridges are associated with the central dome, and sometimes with the flank zones of these uplifts. So, the largest Hawaiian swell is complicated by a volcanic ridge, some of the volcanoes are active. The surface peaks of the ridge form the Hawaiian Islands. The largest one is o. Hawaii is a volcanic massif of several merged shield basalt volcanoes. The largest of them - Mauna Kea (4210 m) makes Hawaii the highest of the oceanic islands of the World Ocean. In the northwest direction, the size and height of the islands of the archipelago decrease. Most of the islands are volcanic, 1/3 are coral.
The most significant swells and ridges in the western and central parts of the Pacific Ocean have a common pattern: they form a system of arched, subparallel in terms of uplifts.
The northernmost arc is formed by the Hawaiian Ridge. To the south is the next, the largest in length (about 11 thousand km), starting with the Cartographers Mountains, which then pass into the Marcus Necker (Midpacific) Mountains, giving way to the underwater ridge of the Line Islands and further passing into the base of the Tuamotu Islands. The underwater continuation of this upland can be traced further to the east up to the East Pacific Rise, where at the place of their intersection there is about. Easter. The third mountain arc begins at the northern part of the Mariana Trench with the Magellan Mountains, which pass into the underwater base of the Marshall Islands, Gilbert Islands, Tuvalu, Samoa. Probably, the ridge of the southern islands of Cook and Tubu a continues this mountain system. The fourth arc begins with the uplift of the North Caroline Islands, which pass into the submarine swell of Kapingamaranga. The last (southernmost) arc also consists of two links - the South Caroline Islands and the Eauriapic submarine swell. Most of the islands mentioned, which mark arched underwater swells on the surface of the ocean, are coral, with the exception of the volcanic islands of the eastern part of the Hawaiian Ridge, the Samoa Islands, and others. - relics of the mid-ocean ridge that existed here in the Cretaceous period (called the Darwin Rise), which in the Paleogene underwent severe tectonic destruction. This uplift extended from the Cartographers Mountains to the Tuamotu Islands.
Blocky ridges are often accompanied by faults that are not associated with mid-ocean uplifts. In the northern part of the ocean, they are confined to submeridional fault zones south of the Aleutian Trench, along which the Northwestern Range (Imperial) is located. Blocky ridges accompany a large fault zone in the Philippine Sea Basin. Systems of faults and blocky ridges have been identified in many basins of the Pacific Ocean.
Various uplifts of the Pacific Ocean floor, together with mid-ocean ridges, form a kind of orographic bottom frame and separate oceanic basins from each other.
The largest basins in the west-central part of the ocean are the Northwestern (6671 m), Northeastern (7168 m), Philippine (7759 m), East Mariana (6440 m), Central (6478 m), West Caroline ( 5798 m), East Caroline (6920 m), Melanesian (5340 m), South Fijian (5545 m), Southern (6600 m) and others. low power bottom sediments, and therefore flat abyssal plains are very limited (the Bellingshausen Basin due to the abundant supply of terrigenous sedimentary material carried from the Antarctic continent by icebergs, the Northeast Basin and a number of other areas). The transport of material to other basins is “intercepted” by deep-water trenches, and therefore the relief of hilly abyssal plains prevails in them.
The bed of the Pacific Ocean is characterized by separately located guyots - seamounts with flat tops, at depths of 2000-2500 m. Coral structures arose on many of them and atolls formed. The guyots, as well as the large thickness of dead coral limestones on the atolls, testify to the significant subsidence of the earth's crust within the Pacific Ocean floor during the Cenozoic.
The Pacific Ocean is the only one whose bed is almost entirely within the oceanic lithospheric plates (Pacific and small - Nazca, Cocos) with a surface at an average depth of 5500 m.
Bottom sediments
The bottom sediments of the Pacific Ocean are exceptionally diverse. Terrigenous sediments are developed in the marginal parts of the ocean on the continental shelf and slope, in the marginal seas and deep-sea trenches, and in some places on the ocean floor. They cover more than 10% of the area of the Pacific Ocean floor. Terrigenous iceberg deposits form a strip near Antarctica 200 to 1000 km wide, reaching 60°S. sh.
Among the biogenic sediments, the largest areas in the Pacific Ocean, as in all others, are occupied by carbonate (about 38%), mainly foraminiferal deposits.
Foraminiferal muds are distributed mainly south of the equator to 60°S. sh. In the Northern Hemisphere, their development is limited to the summit surfaces of ridges and other uplifts, where benthic foraminifers predominate in the composition of these oozes. Pteropod deposits are common in the Coral Sea. Coral sediments are located on the shelves and continental slopes within the equatorial-tropical belt of the southwestern part of the ocean and occupy less than 1% of the ocean floor area. Shellfish, consisting mainly of shells of bivalves and their fragments, are found on all shelves, except for the Antarctic. Biogenic siliceous sediments cover more than 10% of the area of the Pacific Ocean floor, and together with siliceous-carbonate sediments, about 17%. They form three main belts of silicic accumulation: the northern and southern siliceous diatom oozes (at high latitudes) and the equatorial belt of siliceous radiolarian sediments. Pyroclastic volcanic sediments are observed in areas of modern and Quaternary volcanism. Important distinguishing feature bottom sediments of the Pacific Ocean - a wide distribution of deep-sea red clays (more than 35% of the bottom area), which is explained by the great depths of the ocean: red clays are developed only at depths of more than 4500-5000 m.
Mineral resources of the bottom
In the Pacific Ocean there are the most significant areas of distribution of ferromanganese nodules - more than 16 million km 2. In some areas, the content of nodules reaches 79 kg per 1 m 2 (average 7.3-7.8 kg / m 2). Experts predict a bright future for these ores, arguing that their mass production can be 5-10 times cheaper than obtaining similar ores on land.
The total reserves of ferromanganese nodules at the bottom of the Pacific Ocean are estimated at 17 thousand billion tons. Pilot development of nodules is carried out by the United States and Japan.
Phosphorite and barite are distinguished from other minerals in the form of nodules.
Commercial reserves of phosphorites have been found near the California coast, in the shelf parts of the Japanese island arc, off the coast of Peru and Chile, near New Zealand, in California. Phosphorites are mined from depths of 80-350 m. The reserves of this raw material are large in the open part of the Pacific Ocean within the limits of underwater uplifts. Barite nodules have been found in the Sea of Japan.
Placer deposits of metal-bearing minerals are currently of great importance: rutile (titanium ore), zircon (zirconium ore), monazite (thorium ore), etc.
Australia occupies the leading place in their production; placers along its eastern coast stretch for 1.5 thousand km. Coastal placers of cassiterite concentrate (tin ore) are located on the Pacific coast of mainland and insular Southeast Asia. Significant placers of cassiterite off the coast of Australia.
Titanomagnetite and magnetite placers are being developed near about. Honshu in Japan, in Indonesia, in the Philippines, in the USA (near Alaska), in Russia (near Iturup Island). Gold sands are known off the western coast of North America (Alaska, California) and South America (Chile). Platinum sands are mined off the coast of Alaska.
In the eastern part of the Pacific Ocean, near the Galapagos Islands in the Gulf of California and elsewhere in rift zones, ore-forming hydrotherms (“black smokers”) have been identified - outcrops of hot (up to 300-400 ° C) juvenile waters with a high content of various compounds. Here is the formation of deposits of polymetallic ores.
Among non-metallic raw materials located in the shelf zone, glauconite, pyrite, dolomite, building materials - gravel, sand, clay, limestone-shell rock, etc. are of interest. Offshore deposits, gas and hard coal.
Oil and gas shows have been found in many areas of the shelf zone in both the western and eastern parts of the Pacific Ocean. Oil and gas production is carried out by the USA, Japan, Indonesia, Peru, Chile, Brunei, Papua, Australia, New Zealand, Russia (near Sakhalin Island). The development of oil and gas resources of the Chinese shelf is promising. The Bering, Okhotsk and Japanese seas are considered promising for Russia.
In some areas of the Pacific shelf, coal-bearing seams occur. The extraction of coal from the bowels of the seabed in Japan is 40% of the total. On a smaller scale, coal is mined by sea in Australia, New Zealand, Chile and some other countries.
Magellan discovered the Pacific Ocean in the autumn of 1520 and called the ocean the Pacific Ocean, “because, according to one of the participants, during the transition from Tierra del Fuego to the Philippine Islands, more than three months, we never experienced the slightest storm.” By the number (about 10 thousand) and the total area of the islands (about 3.6 million km²), the Pacific Ocean ranks first among the oceans. In the northern part - the Aleutian; in the western - Kuril, Sakhalin, Japanese, Philippine, Greater and Lesser Sunda, New Guinea, New Zealand, Tasmania; in the central and southern - numerous small islands. The bottom relief is varied. In the east - the East Pacific Rise, in the central part there are many basins (North-Eastern, North-Western, Central, Eastern, Southern, etc.), deep-water trenches: in the north - Aleutian, Kuril-Kamchatsky, Izu-Boninsky; in the west - Mariana (with a maximum depth of the World Ocean - 11,022 m), Philippine, etc.; in the east - Central American, Peruvian, etc.
The main surface currents: in the northern part of the Pacific Ocean - warm Kuroshio, North Pacific and Alaska and cold California and Kuril; in the southern part - warm South Trade Winds and East Australian and cold West Winds and Peruvian. The water temperature on the surface near the equator is from 26 to 29 ° C, in the subpolar regions up to −0.5 ° C. Salinity 30-36.5 ‰. The Pacific Ocean accounts for about half of the world's fish catch (pollock, herring, salmon, cod, sea bass, etc.). Extraction of crabs, shrimps, oysters.
Important sea and air communications between the countries of the Pacific basin and transit routes between the countries of the Atlantic and Indian Oceans run through the Pacific Ocean. Major ports: Vladivostok, Nakhodka (Russia), Shanghai (China), Singapore (Singapore), Sydney (Australia), Vancouver (Canada), Los Angeles, Long Beach (USA), Huasco (Chile). The International Date Line runs along the 180th meridian across the Pacific Ocean.
Plant life (except bacteria and lower fungi) is concentrated in the upper 200th layer, in the so-called euphotic zone. Animals and bacteria inhabit the entire water column and the ocean floor. Life develops most abundantly in the shelf zone, and especially near the coast at shallow depths, where the flora of brown algae and a rich fauna of mollusks, worms, crustaceans, echinoderms, and other organisms are diversely represented in the temperate zones of the ocean. In tropical latitudes, the shallow water zone is characterized by the widespread and strong development of coral reefs, and mangroves near the shore. With the advancement from cold zones to tropical ones, the number of species sharply increases, and the density of their distribution decreases. About 50 species of coastal algae - macrophytes are known in the Bering Strait, over 200 off the Japanese Islands, over 800 in the waters of the Malay Archipelago. There are about 4000 known species of animals in the Soviet Far Eastern seas, and at least 40-50 thousand in the waters of the Malay Archipelago . In the cold and temperate zones of the ocean, with a relatively small number of plant and animal species, due to the mass development of some species, the total biomass greatly increases; in the tropical zones, individual forms do not receive such a sharp predominance, although the number of species is very large.
With distance from the coasts to the central parts of the ocean and with increasing depth, life becomes less diverse and less abundant. In general, the fauna of T. o. includes about 100 thousand species, but only 4-5% of them are found deeper than 2000 m. At depths of more than 5000 m, about 800 species of animals are known, more than 6000 m - about 500, deeper than 7000 m - slightly more than 200, and deeper than 10 thousand m - only about 20 species.
Among coastal algae - macrophytes - in temperate zones, fucus and kelp are especially distinguished by their abundance. In tropical latitudes, they are replaced by brown algae - Sargasso, green - Caulerpa and Galimeda and a number of red algae. The surface zone of the pelagial is characterized by the massive development of unicellular algae (phytoplankton), mainly diatoms, peridiniums and coccolithophorids. In zooplankton, the most important are various crustaceans and their larvae, mainly copepods (at least 1000 species) and euphausids; a significant admixture of radiolarians (several hundred species), coelenterates (siphonophores, jellyfish, ctenophores), eggs and larvae of fish and benthic invertebrates. In T. o. one can distinguish, in addition to the littoral and sublittoral zones, a transitional zone (up to 500-1000 m), bathyal, abyssal and ultraabyssal, or a zone of deep-water trenches (from 6-7 to 11 thousand m).
Planktonic and benthic animals serve as abundant food for fish and marine mammals (nekton). The fish fauna is exceptionally rich, including at least 2,000 species in tropical latitudes and about 800 in the Soviet Far Eastern seas, where, in addition, there are 35 species of marine mammals. The most commercially important fish are: anchovies, Far Eastern salmon, herring, mackerel, sardine, saury, sea bass, tuna, flounder, cod and pollock; from mammals - sperm whale, several species of minke whales, fur seal, sea otter, walrus, sea lion; from invertebrates - crabs (including Kamchatka), shrimps, oysters, scallops, cephalopods and many others; from plants - kelp (seaweed), agaronos-anfeltia, sea grass zoster and phyllospadix. Many representatives of the fauna of the Pacific Ocean are endemic (pelagic cephalopod nautilus, most Pacific salmon, saury, greenling fish, northern fur seal, sea lion, sea otter, and many others).
The large extent of the Pacific Ocean from North to South determines the diversity of its climates - from equatorial to subarctic in the North and Antarctic in the South. Most of the ocean surface, approximately between 40 ° north latitude and 42 ° south latitude, is located in the zones of equatorial, tropical and subtropical climates. The circulation of the atmosphere over the Pacific Ocean is determined by the main areas of atmospheric pressure: the Aleutian Low, the North Pacific, South Pacific and Antarctic Highs. The indicated centers of action of the atmosphere in their interaction determine the great constancy of northeast winds in the North and southeast winds of moderate strength - trade winds - in the tropical and subtropical parts of the Pacific Ocean and strong westerly winds in temperate latitudes. Especially strong winds are observed in the southern temperate latitudes, where the frequency of storms is 25-35%, in the northern temperate latitudes in winter - 30%, in summer - 5%. In the West of the tropical zone, from June to November, tropical hurricanes - typhoons are frequent. The monsoon circulation of the atmosphere is typical for the northwestern part of the Pacific Ocean. The average air temperature in February decreases from 26-27°C near the equator to -20°C in the Bering Strait and -10°C off the coast of Antarctica. In August, the average temperature varies from 26-28°C near the equator to 6-8°C in the Bering Strait and to -25°C off the coast of Antarctica. Throughout the Pacific Ocean, located north of 40 ° south latitude, there are significant differences in air temperature between the eastern and western parts of the ocean, caused by the corresponding dominance of warm or cold currents and the nature of the winds. In tropical and subtropical latitudes, the air temperature in the East is 4–8 °C lower than in the West. In the northern temperate latitudes, the opposite is true: in the East, the temperature is 8–12 °C higher than in the West. The average annual cloudiness in areas of low atmospheric pressure is 60-90%. high pressure - 10-30%. The average annual precipitation at the equator is more than 3000 mm, in temperate latitudes - 1000 mm in the West. and 2000-3000 mm to the east. The least amount of precipitation (100-200 mm) falls on the eastern outskirts of the subtropical regions of high atmospheric pressure; in the western parts, the amount of precipitation increases to 1500-2000 mm. Fogs are typical for temperate latitudes, they are especially frequent in the area of the Kuril Islands.
Under the influence of the atmospheric circulation developing over the Pacific Ocean, surface currents form anticyclonic gyres in subtropical and tropical latitudes and cyclonic gyres in northern temperate and southern high latitudes. In the northern part of the ocean, circulation is formed by warm currents: the Northern Trade Wind - Kuroshio and the North Pacific and cold California currents. In the northern temperate latitudes, the cold Kuril Current dominates in the West, and the warm Alaska Current dominates in the East. In the southern part of the ocean, the anticyclonic circulation is formed by warm currents: the South Equatorial, East Australian, zonal South Pacific and cold Peruvian. To the north of the equator, between 2-4° and 8-12° north latitude, the northern and southern circulations are separated during the year by the Intertrade (Equatorial) countercurrent.
The average temperature of the surface waters of the Pacific Ocean (19.37 ° C) is 2 ° C higher than the temperature of the waters of the Atlantic and Indian Oceans, which is the result of the relatively large size of that part of the Pacific Ocean area, which is located in well-heated latitudes (over 20 kcal / cm2 per year). ), and limited communication with the Arctic Ocean. The average water temperature in February varies from 26-28 °С near the equator to -0.5, -1 °С north of 58° north latitude, near the Kuril Islands and south of 67° south latitude. In August, the temperature is 25-29 °С near the equator, 5-8 °С in the Bering Strait and -0.5, -1 °С south of 60-62 ° south latitude. Between 40 ° south latitude and 40 ° north latitude, the temperature in the eastern part of the T. o. 3-5 °C lower than in the western part. To the north of 40 ° north latitude - on the contrary: in the East, the temperature is 4-7 ° C higher than in the West. To the south of 40 ° south latitude, where zonal transport of surface waters prevails, there is no difference between water temperatures in the East and in the West. In the Pacific Ocean, there is more rainfall than evaporating water. Taking into account the river runoff, more than 30 thousand km3 of fresh water comes here annually. Therefore, the salinity of the surface waters of the T. o. lower than in other oceans (average salinity is 34.58‰). The lowest salinity (30.0-31.0‰ and less) is observed in the West and East of the northern temperate latitudes and in the coastal regions of the eastern part of the ocean, the highest (35.5‰ and 36.5‰) - respectively in the northern and southern subtropical latitudes. At the equator, water salinity decreases from 34.5‰ or less, in high latitudes - to 32.0‰ or less in the North, to 33.5‰ or less in the South.
The density of water on the surface of the Pacific Ocean increases fairly evenly from the equator to high latitudes in accordance with general character distribution of temperature and salinity: at the equator 1.0215-1.0225 g/cm3, in the North - 1.0265 g/cm3 or more, in the South - 1.0275 g/cm3 or more. The color of the water in the subtropical and tropical latitudes is blue, the transparency in some places is more than 50 m. In the northern temperate latitudes, the dark blue color of the water prevails, off the coast it is greenish, the transparency is 15-25 m. In the Antarctic latitudes, the color of the water is greenish, the transparency is up to 25 m .
Tides in the northern part of the Pacific Ocean are dominated by irregular semidiurnal (height up to 5.4 m in the Gulf of Alaska) and semidiurnal (up to 12.9 m in the Penzhina Bay of the Sea of Okhotsk). Near the Solomon Islands and off part of the coast of New Guinea, daily tides, up to 2.5 m. 40° north latitude. The maximum height of wind waves in the Pacific Ocean is 15 m or more, the length is over 300 m. Tsunami waves are characteristic, especially often observed in the northern, southwestern and southeastern parts of the Pacific Ocean.
Ice in the northern part of the Pacific Ocean is formed in seas with severe winter climatic conditions (Bering, Okhotsk, Japanese, Yellow) and in bays off the coast of Hokkaido, the Kamchatka and Alaska peninsulas. In winter and spring, ice is carried by the Kuril current to the extreme northwestern part of the Pacific Ocean. Small icebergs are found in the Gulf of Alaska. In the South Pacific, ice and icebergs form off the coast of Antarctica and are carried by currents and winds into the open ocean. The northern limit of floating ice in winter passes at 61-64 ° S, in summer it shifts to 70 ° S, icebergs at the end of summer are carried up to 46-48 ° S. Icebergs form mainly in the Ross Sea.
The Pacific Ocean is the largest ocean in terms of size, with the greatest average and maximum measured depths. The marginal seas of the Pacific Ocean include: Bering, Okhotsk, Japan, East China, Philippine, South China, Coral and Tasmanovo, as well as other, smaller seas of Indonesia, the New Guinea and Solomon Seas. In the Encyclopedia, the Arafura and Timor Seas refer to the seas of the Indian Ocean, and the Scotia Sea (also sometimes included in the Pacific Ocean) to the seas of the Southern Ocean. The Fiji Sea is included in the descriptions of the southwestern sector of the Pacific Ocean. The boundary between the northern and southern parts of the Pacific Ocean is the equator; the Galapagos and Gilbert Islands, located on the equator, belong to the South Pacific Ocean.
In addition to the marginal seas. The International Hydrographic Bureau distinguishes between individual marginal waters: the Gulf of Alaska (1533 thousand km3), Queen Charlotte, the Gulf of California (160 thousand km-) and the Bass Strait (70 thousand km2).
The Pacific Ocean extends 15,500 km from the Bering Strait to Cape Adair and 17,200 km from Panama to Mindanao, or 24,000 km if this line is extended to the Gulf of Thailand. The area of the Pacific Ocean (together with the marginal seas) is 169,000,000 km2, the average depth is 4028
Pacific borders
The western boundary runs along the meridian from Singapore to the island of Sumatra (Strait of Malacca) (according to Kossin) or along the northern edge of the Strait of Malacca (according to the International Hydrographic Bureau), or along the linden northwest of the Pedro Peninsula (according to Murchson); then the border follows the line of the island of Sumatra - the island of Java - the island of Roti - the island of Timor. Opinions are divided whether the Timor and Arafura Seas and the Gulf of Carpentaria should be attributed to the Indian Ocean basin or to the Pacific Ocean basin.Eastern border. All experts agree on the definition of Cape Horn as the boundary point. Further, the boundary goes along the meridian 68°04" W to the Antarctic Peninsula. The northern boundary passes with the Chukchi Sea.
Climate
In the northern hemisphere in winter, in the Pacific Ocean, in comparison with other oceans, the greatest zonal stability of atmospheric processes is observed, which is determined by the almost symmetrical arrangement of the main pressure centers in both hemispheres. In addition, in the Pacific Ocean there is a subtropical convergence zone with a wide belt of equatorial calm and two semi-permanent anticyclones: North Pacific, or Hawaiian and South Pacific. In the summer of the northern hemisphere, these anticyclones intensify and their centers are located at 40°N. sh. and 30°S sh. respectively. In the winter of the northern hemisphere, the North Pacific anticyclone weakens and shifts somewhat to the southeast. The South Pacific High does not change in the winter of the southern hemisphere. Due to the very cold Peruvian current in the east and the rise in temperature under the influence of the monsoons in the area of Australia and the Solomon Islands in the west, the South Pacific anticyclone is shifting to the east.trade winds spread on both sides of the equator up to 25 °, the southeast trade winds in the summer of the southern hemisphere shift somewhat north of the equator, in the same direction there is a slight movement of the thermal equator. The trade winds in the Pacific Ocean are less constant and usually weaker than the trade winds in other oceans. In the eastern parts of the Pacific, the trade winds are stronger and more noticeable. The thermal equator lies at about 5°N. sh., and on this parallel there are very heavy rains.
Monsoons quite significant in both the northwestern and southwestern Pacific Ocean. In the northwestern part of the summer of the northern hemisphere, the southeast monsoon affects the entire Southeast. East Asia, most of China and the marginal seas of the Pacific Ocean up to 145 ° E. d. Mariana Islands and even south to the equator, where the same air current expands with the southeast trade winds and the Australian High becomes the southeast monsoon of East India. The Southwest Pacific Ocean is subject to the northwest monsoon during the southern hemisphere summer, affecting the climate of New Guinea, Northern Australia, the Solomon Islands, New Caledonia and, to a lesser extent, the Fiji Islands.
While over most of the eastern half of the Pacific Ocean there is a very slight seasonal shift in the boundaries of the trade winds, in the western half there is a change in wind direction by 180 °. This is most noticeable in the Pacific Northwest, because during the northern hemisphere winter, the development of the Siberian High results in a strong outflow of very hard, dry northwest air, which creates a climate in Northeast China similar to that of the northeastern United States. But this climate is more severe, since the Canadian anticyclone is only rarely as strong as the Siberian one.
In the high latitudes of the North Pacific Ocean, a semi-permanent Aleutian cyclone (stronger in winter) is associated with the polar front, which often runs from Japan to Alaska, and westerly winds are enhanced by a strong winter runoff of cold air masses from Siberia. In summer, these conditions change due to a cyclone over Siberia and the Aleutian cyclone moves north and becomes much weaker.
In the same latitudes of the South Pacific Ocean, the Australian anticyclone, as a rule, does not block western disturbances, because the polar fronts pass mainly over the Southern Ocean, while heavy winter rains fall over Southeast Australia and the islands of New Zealand. Between the islands of New Zealand and the coast of Southern Chile, in the main westerly belt, there is not a single island at a distance of 8000 km.
Currents of the Pacific Ocean
The surface currents of the Pacific Ocean arise as a result of the trade winds and westerly winds. The surface flow is mainly westward at low latitudes and eastward at high latitudes. Near the continents, zonal flows deviate to the north and south and form currents along the eastern and western boundaries of the Pacific Ocean. A system of cyclonic and anticyclonic gyres is formed along the equator.In the middle latitudes, large subtropical anticyclonic circulations prevail: western boundary currents (Kuroshio in the north and East Australian in the south. Parts of the western wind drift current, eastern boundary currents (California current in the north. Peruvian in the south). Northern and southern trade wind currents having a western a direction located a few degrees north and south of the equator.
In the higher latitudes of the southern hemisphere, there is the Circumpolar Antarctic Current, going east around Antarctica, and in the northern hemisphere, a subarctic circular circulation, consisting of the Alaska Current, the Kuril Current (Oyashio), going southwest along Kamchatka and the Kuril Islands, and parts of the North Pacific.
In the region of the equator, the North and South Trade-wind currents go westward, and between them in the band 5-10 ° N. sh. to the east is the Intertrade countercurrent.
The highest speed is observed in the Kuroshio Current (more than 150 cm/s). Velocities up to 50 cm/s are observed in the westerly flow near the equator and in the Circumpolar Antarctic Current. Velocities from 10 to 40 cm/s occur at the eastern boundary of the California and Peruvian currents.
Subsurface countercurrents have been found under the eastern boundary currents and along the equator. Under the Californian and Peruvian currents there are currents 50-150 km wide, directed poleward and extending from a horizon of 150 m down to several hundred meters. In the California Current system, the countercurrent also appears on the surface during the winter months.
The intertrade subsurface countercurrent is a narrow (300 km wide) fast flow (up to 150 cm/s) running eastward at the equator under the western surface current. This current is located approximately at a depth of 50-100 m and spreads from 160 ° E. to the Galapagos Islands (90°W).
Surface layer temperature varies from freezing at high latitudes to 28°C or more at low latitudes in winter. The isotherms are not always directed in latitude, since some currents (Kuroshio, East Australian, Alaska) carry warmer water towards high latitudes, while other currents (California, Peru, Kuril) carry cold water towards the equator. Moreover, the rise of cold deep water in the eastern boundary currents and at the equator also influences the distribution of heat.
Salinity of water surface layer reaches a maximum in the middle latitudes, where evaporation exceeds precipitation. The highest salinity values are slightly higher than 35.5 and 36.5 ppm. respectively in the northern and southern subtropical anticyclonic circulations. The salinity of water is much lower at high and low latitudes, where precipitation exceeds evaporation. The salinity of the waters of the open ocean is 32.5 ppm. in the north and 33.8 prom in the south (near Antarctica). Near the equator, the lowest salinity values (less than 33.5 ppm) are observed in the eastern part of the Pacific Ocean. Under the influence of circulation, salinity is redistributed. The California and Peruvian currents carry low salinity waters from high latitudes towards the equator, while the Kuroshio carries high salinity waters from the equatorial region towards the pole; subtropical closed circulations turn out to be, as it were, lenses of water of high salinity, surrounded by waters of low salinity.
The oxygen concentration in the surface layer is always very close to saturation because the upper layers are in contact with the atmosphere. The amount of saturation depends on both temperature and salinity, but the role of temperature is much greater, and the overall distribution of oxygen on the surface largely reflects the distribution of temperature. The oxygen concentration is high in cold waters of high latitudes and low in warm equatorial waters. At greater depths, the oxygen concentration decreases. The degree of oxygen saturation is used as an indicator of the "age" of water - the time elapsed since the last contact of water with the atmosphere.
Top water circulation takes place under the influence of the wind. The adaptation of the density field to geostrophic equilibrium, as well as the convergence and divergence caused by the wind, lead to the formation of deep currents that are completely different from surface ones. At greater depths, where the circulation is mostly thermohaline, the differences are even greater in subtropical wind-driven anticyclonic circulations, there is convergence of the water surface, and the accumulation of water leads to the formation of a mixed layer (up to 300 m thick in the western Pacific during winter). Similarly, the divergence of surface waters in high-latitude cyclonic circulations leads to the rise of deep waters to the surface, and then to their spread to the periphery of cyclones. Along the coasts of North and South America at mid-latitudes, winds directed towards the equator cause surface water to move away from the coast, as a result of which deep water rises to the surface. At the equator, westerly winds and the rotation of the Earth cause surface water to move both south and north from the equator. which also leads to the rise of deep waters. Anticyclonic circulations are thus large lenses of less dense water. They are supported by wind-driven convergence of waters, as well as heating and evaporation.
In the subtropics of the Pacific Ocean, lenses of warm saline water propagate downward to a depth of more than 500 m. As a result, lenses of cold water of low salinity are formed here. A similar picture, although to a lesser extent, is characteristic of the equatorial region.
Characteristics of water masses and deep circulation. In the high latitudes of the North Pacific, surface waters are so low in salinity that even cooling to the freezing point will not give them sufficient density to sink deeper than the 200 m horizon. The deep waters of the North Pacific Ocean come from the South Pacific Ocean (since water exchange with the Arctic Ocean the ocean is small). These deep waters, which form in the Weddell Sea in the North Atlantic (where a certain temperature-salinity ratio forms very dense water on the surface), are constantly replenished.
Oxygen enters the surface waters of the ocean from the atmosphere. The waters sinking into the Weddell Sea in the North Atlantic are rich in oxygen, and they oxygenate the deep waters of the Pacific Ocean as they move north. Compared to the high oxygen content at the surface and at the bottom, the oxygen content at intermediate depths is much lower, and in some parts of the subtropical There is almost no oxygen in the northern part of the Pacific Ocean.
Distribution of nutrients in the Pacific Ocean depends on the water circulation system. Inorganic phosphates are consumed when plants grow on the surface and are regenerated at great depths when plants sink and decompose. As a result, nutrients are usually higher at depths of 1 to 2 km than at the surface. The deep waters of the Pacific Ocean are richer in phosphates than those of the Atlantic. Since the outflow of water from the Pacific Ocean occurs mainly due to surface waters, which are poorer in phosphates, phosphates accumulate in the Pacific Ocean, and their average concentration is approximately twice as high as in the Atlantic.
Bottom sediments
The longest sediment cores taken from the bottom of the Pacific Ocean reached 30 m, but most of the cores did not exceed 10 m. Experimental deep-sea drilling in two areas—near San Diego (California) and near Guadalupe Island—made it possible to significantly increase the depth of the study.
The total thickness of sediments in the Pacific Ocean is unknown. However, according to geophysical data, a layer of non-consolidated sediments is approximately 300 m. Under this layer there is a second layer about 1 km thick, which is represented by consolidated sediments and volcanic rocks, but a more complete picture of these two layers can be obtained only as a result of deep-sea drilling. While drilling for the Mohol project off the coast of Southern California, basalt was discovered under a 200-meter layer of sediment.
Volcanic precipitation
In some areas of the Pacific Ocean, there are layers of sediments, almost entirely consisting of fragments of unaltered volcanic rocks. Such material may be distributed to large area in case of surface eruptions. During underwater eruptions, the area of distribution of such precipitation will be much smaller. Underwater alteration of volcanic silt and its mixing with other sediments leads to the formation of a continuous series of intermediate varieties of sediments of mixed origin. For volcanic sediments, lavas of the andesite and rhyolite type are the parent lavas, because their eruption is explosive and they are sufficiently resistant to secondary changes. Sediments near Indonesia, Central America, and in the Gulf of Alaska contain significant amounts of this kind of material. Basaltic volcanic sediments occur locally, due to the fact that the volcanic material of the basic composition, compared with the acidic, quickly decomposes with the formation of autogenous minerals. Modification of glassy clasts is one of the most important reactions resulting in the formation of aluminosilicates found in near-surface ocean sediments.
Coral reefs
Coral reefs are wave-resistant ecological features composed primarily of hermatypic corals and calcareous algae. Coral reefs border the continents and islands of the Pacific Ocean in areas where the temperature is at least 18 ° C. In the sediments of reef lagoons, coral fragments, foraminifera and fine-grained carbonate silt are found. Reef fragments spread along the edges of oceanic islands to the abyssal depths, where they undergo the same dissolution processes as foraminiferal calcium carbonate. On some coral islands, dolomite has been found at a certain depth. it also occurs in abyssal sediments near coral islands and is probably formed from calcium carbonate supplied from them, which expands in deep waters. In areas where there is little rainfall, coral rocks, as a result of reaction with phosphate from guano, are modified into phosphate rocks, consisting of apatite. The Lower Eocene phosphatized fauna was found on the Sylvania Guyot. There are also reactions of calcium carbonate with phosphates dissolved in sea water; Early Eocene phosphatized fauna was found on the Sylvania Guyot.History of the development of the Pacific Ocean
For more than a hundred years, scientists have been trying to solve one of the greatest mysteries of geology - to restore the tectonic history of the Pacific Ocean. In its size, structure, paleogeography, the Pacific Ocean differs from all other oceans of the globe.The Pacific Ocean is the largest ocean on earth, with many more volcanoes, seamounts, and atolls at its bottom than all the other oceans combined. The Pacific Ocean is surrounded on all sides by the longest continuous belts of folded mountains, replete with active volcanoes, where earthquakes occur more often than in any other area of \u200b\u200bthe globe. The propagation of seismic waves under the crust of the Pacific Ocean occurs at a shallower depth from the surface and at a higher speed than in other oceans.
The bottom of the central part of the ocean is covered with more than thin layer precipitation than in other oceans, so here you can better study the features of the underlying crust. All these features are enough to show why geologists and geophysicists consider the Pacific Ocean unique in geotectonic terms.
Geotectonic zoning within the Pacific Ocean clearly distinguishes between two physiographic provinces: 1) the main, or central. The Pacific basin and 2) marginal seas with numerous ridges and depressions of the second order located within them.
Pacific basin
In general, the bottom of the Pacific Ocean is a gently undulating abyssal plain; its individual parts are exceptionally aligned for tens and sometimes hundreds of kilometers. Its average depth is 5000 m.
This plain is traversed by numerous seamounts or volcanic ridges and countless elevations ranging from small hills to fairly massive (conical) seamounts. The East Pacific Rise, which is a continuation of the Mid-Ocean Ridge, extends from Antarctica to the southern tip of New Zealand, capturing the Pacific-Antarctic Ridge. The Easter Island Rise and the Galapagos Rise, and ends at America in the Gulf of California. In terms of its geomorphological features, this uplift is similar to other mid-ocean ridges of the Atlantic and Indian Oceans, but in its shape it is surprisingly asymmetric and noticeably deviates towards the American mainland. The small forms of its relief are the same as those of other submarine ridges of this type. The ridge is marked by a narrow rift or a series of graben structures, and most of the slopes are complicated by irregular (extending for about 1000 km) ridges and trenches located parallel to the uplift axis. The average height of these ridges is 2000-3000 m above the level of the bottom of the central part of the Pacific Ocean; in addition, it also includes local accumulations of small volcanic islands and seamounts. It can be assumed that the Juan de Fuca Ridge near Vancouver Island is a continuation of the main ridge.
Submarine fans and abyssal plains
Almost along the entire northeastern edge of the ocean there are numerous fans, quite large, which in some places pass into the abyssal plains. However, the number of the latter in the Pacific Ocean is small, since usually narrow oceanic trenches act as "traps" for sedimentary material, preventing further movement of turbidity flows.
Archipelagos of the Western and Central Pacific with volcanic islands, submarine rises and atolls. This area is characterized by rectilinear subparallel belts of volcanic islands, submarine ridges and atolls. Fan-shaped from the foothills of these underwater ridges diverge sediment cones, which everywhere form slightly inclined slopes, gradually merging with the ocean floor (approximately 5000-6000 m). An interesting feature of most underwater ridges (an example is the ridge whose peaks are represented by the Hawaiian Islands) is the presence of shallow depressions that almost completely surround the island slopes.
Archipelagos of the Central Pacific occupy 13.7% of its area. The height of the islands is different. An example of high islands is the Tahiti chain, while the Tuamotu chain parallel to it is under water and is represented only by atolls on the surface. Main plain with low relief. It occupies most of the Pacific Ocean at a depth of 5000-6000 m. This plain is extremely flat, and there are no gentle slopes typical of abyssal plains, directed in one direction. The relief of the plain is rather undulating and is a system of conjugated low ridges and shallow depressions with elevations of about 300 m and distances between the tops of the ridges of about 200 km. In some areas, the maximum relative elevation does not even reach 60 m, while in others it can reach 500 m or more. Separate submarine ridges occasionally rise above the surface of the plain, but their number is small, with the exception of certain areas - island arcs or such specific provinces as the Gulf of Alaska.
Fault zones (linear ledges)
Large fault zones stretch for long distances (up to 2000 km), they cross the low relief plains of the northeastern sector of the Pacific Ocean and the East Pacific Rise.
Peripheral zone of island arcs and trenches
The boundaries of the main part of the Pacific Basin are fixed, as a rule, by a zone of deep-water trenches; on the side of the continents, these trenches are bordered by rocky mountains or arches of islands associated with one or more submarine ridges. In the western part of the Pacific Ocean, these island arcs and trenches are isolated and separated from the mainland by intermediate depressions, as a result of which the influx of sediments in the trench is insignificant, and most of them remain unfilled with sediments. These western trenches are extremely narrow, their bottom is flat due to a small influx of sediments. The slopes are steep, the steepness is 25-45°.
Along the eastern edge of the Pacific Ocean, the coastal Cordilleras are cut by large rivers that carry large amounts of sedimentary material into the depressions, in some cases completely filling them. The island arcs themselves are located on a double ridge; the outer islands are inherently non-volcanic, or at least not active volcanoes, while the inner zone contains many active or very recently extinct volcanoes. This is the so-called famous "fiery belt" of the Pacific Ocean.
marginal seas
They are located only in the western part of the Pacific Ocean and separate the island arcs from the mainland. There are several secondary inland seas, they reach a width of 500-1000 km and about the same length. The bed topography of these seas is exceptionally diverse and, like the main basin, reflects their tectonic history and existing sources of drift. According to sounding data, the following main types of relief are distinguished.
Volcanic hills- an exceptionally disorderly heap of hills with steep, precipitous slopes, similar to volcanic cones, which completely cover the bottom of more distant depressions, such as the Pandora depression.
abyssal plains- flat, even or slightly sloping plains covered with sediments brought by fast bottom currents, such as turbidity. It is hard to imagine how otherwise such plains could form. In addition, the surface of this type is always somewhat higher (50-100 m) in the place where sediments from the mainland enter the sea. For example, the Tasman Basin is slightly shallower in the northwest, just opposite the Sydney, Hawkesburn and Hanger rivers that flow into it. There is a similar shallow water in the northeast of the Fiji Sea, where the Rewa (powerful tropical stream) flows into it, pouring out from the Fiji Islands. The largest of the basins of this type has a depth of up to 5000 m, smaller basins are characterized by the smallest depths - from 2000 to 4000 m.
Areas of microcontinental blocks found in numerous areas; they are a heap of quasi-cratonic blocks of large and small sizes, sometimes the distance between these regions is only a few kilometers, but more often they are separated from each other by hundreds of kilometers. The Melanesian plateau is a complex of this type.
underwater plateau widely distributed in the Pacific Ocean at shallow or medium depths. Plateaus are separated from the mainland. Typical examples: the Coral Sea plateau, the Belloy plateau in the southwestern part of the Pacific Ocean. Their usual depth is 500-2000 m; numerous coral atolls rise from the surface of the plateau.
Ridges and uplifts of the transition zone. The entire region is crossed by positive structures: either wide domed uplifts or narrow, strongly dissected ridges. These structures are associated with small volcanoes, seamounts and sometimes atolls. The main line of the ridges is almost continuous and runs almost parallel to the main peripheral belt of island arcs and trenches. Some of them end on the surface with such islands as the Japanese, Philippine, New Guinea, New Caledonia, New Zealand, etc.
Troughs and deep sea trenches the transition zone is usually associated with the aforementioned positive landforms. They usually occur in pairs, i.e., a large uplift usually corresponds to an equally large parallel depression. It is interesting that a trench or depression is usually located on the mainland side of the ridge at the bottom of the Mediterranean or marginal sea, i.e. they have a completely opposite orientation than
peripheral belt of the Central Pacific Ocean.
Features of the structure of the Pacific Ocean. The Pacific Ocean is in many ways different from the rest of the world's oceans. It gave its name to three concepts: Pacific coastlines, Pacific volcanism, Pacific type of crust.
Pacific coastlines. A characteristic feature of the Atlantic-type coasts is that the coastline cuts off the tectonic structures of the mainland; this is due to faults that extend along the coast with the subsidence of individual large tectonic blocks or, generally speaking, with disturbances in continuous structures that originally stretched from the mainland into the ocean. In contrast to the Atlantic, the Pacific type of coasts reflects the continuous, continuous linear strike of the Pacific Ocean systems of folded mountains, island arcs, and adjacent marginal depressions. The Pacific Ocean is a flooded foreland on which peripheral folded belts pile up. The main distinguishing feature of the Pacific type of coasts is parallelism, i.e. mountains, coasts, beaches, reefs, trenches tend to maintain linearity and are located on the periphery relative to the central part of the Pacific Ocean.
Parallel ancient terraces of various heights run along the main line of the Pacific-type coast; sometimes, within a few kilometers, the height changes by 1000 m. The main trend of the relief is positive. The secondary terraces of the Pacific type are less active, but their height is also unstable, the Pliocene terraces of Southeast Australia can reach a height of 2000 m (southern part of New South Wales). However, most of the coastline of the secondary type is characterized by faults, negative landforms predominate.
Pacific volcanoes Pacific lavas are mainly confined to the belts of the circum-Pacific folding, and not the central part of the Pacific Ocean. The main rocks are andesites, rhyolites and olivine basalts. The Atlantic type of volcanism is characterized by alkaline lavas; it is regionally associated with stretch or shear zones.
Pacific bark. Based on geophysical studies of the earth's crust, it has been established that the character of the Pacific Ocean's crust is somewhat specific, although there are areas with similar structures in other oceans. The most significant fluctuations in the values of gravity Vening-Meines recorded over the peripheral arcs. Based on the data obtained, it can be assumed that there is an uncompensated mass deficit along the trenches and an excess mass under the island arcs. Mid-ocean ridges are characterized by the presence of lighter material in thick "roots".
Analysis of seismic data on earthquakes and sounding data shows that under a layer of water 5–6 km thick in the central part of the Pacific Ocean there is a layer of sediments with a thickness of 0.5–1.0 km - the “second layer” is, apparently, water-bearing igneous rocks. type of serpentinite; however, some geologists believe that this layer is formed by consolidated sediments. The second layer lies on the section of the Mohorović surface
Systematic surveys with a towed magnetometer in the Pacific Northeast showed the presence of alternating highly and weakly magnetized rocks, oriented from north to south, which had a lateral displacement due to large latitudinal faults.
Intermediate crust in the western Pacific. A wide zone of marginal seas, stretching along the western borders of the Pacific Ocean from the Bering and Okhotsk to the Coral and Tasman Seas, is perhaps one of the most interesting features of the Pacific Ocean. In other oceans there are marginal seas, but in no other ocean are these seas so large and so numerous; moreover, nowhere except the Pacific Ocean, they are located along the western border.
It is quite clear that the general geology of these marginal seas in the western Pacific is fundamentally different from that of the central Pacific. The line between these two provinces in the western part of the Pacific Ocean also separates two huge physiographic regions: the central part of the Pacific Ocean and the western marginal seas.
Deep sea trenches and island arcs. The main part of the Pacific Ocean has another significant feature: an almost continuous belt of trenches or ditches runs along the chain of island arcs on the oceanic side and the coastal Cordillera. Similar landforms exist locally in other oceans, but they do not form a peripheral belt there. These belts correspond to strong negative gravity anomalies. Behind these belts, on the mainland side, there is a belt of positive gravity anomalies. Similar belts of positive and negative anomalies are also found in other oceans, but in the Pacific Ocean they are especially widespread. Several important points should be noted in the distribution of the Pacific island arcs.
island arcs found only in the western part of the Pacific Ocean, in the east they correspond to the coastal cordillera. Thus, both of these forms are similar in the geotectonic sense, but they are not identical, since there are marginal seas that are located between the continents and island arcs. Such seas also exist within the Antilles and Scotia arcs, which are quasi-Pacific structures protruding towards the Atlantic Ocean.
Island arcs usually consist of two rows of islands, the outer line being mostly non-volcanic islands, while the inner line islands are mostly volcanoes. Dislocated and faulted sediments of Mesozoic age occur on the outer arc. The distance between rows is usually 50-150 km. In some cases, volcanoes are completely absent on one of the arcs. The "fiery belt" of the Pacific Ocean is not continuous everywhere.
Island arcs, as the name implies, have the shape of a semicircle. The bend radius varies from 200 to 2000 km. However, in some cases, such as the Tonga and Kermadec trenches, both rows of islands are rectilinear. Deep-sea trenches and arcs are complexly interconnected with the seismic zone, which belongs to the most intense seismic belts of the globe.
The trace of the so-called uplifting fault surface as a whole is a uniform distribution of earthquake sources along a simple plane, but the epicenters do not really clearly reflect the levels of earthquake shocks. Some geologists believe that earthquake shocks are accompanied by faults, and many large zones of the western Pacific trenches are now well correlated with horizontal displacement faults.
Pacific Stability The question of the constancy of continents and oceans belongs to the philosophical aspect of geology. It was put forward for discussion in the last century, but has not yet been resolved. This issue is considered from three points of view: 1) biogeographic, 2) geochemical and geophysical, 3) geotectonic. Each of these points of view needs careful analysis.
Biogeographic transoceanic connections. At the Pacific Congress in 1971 in Honolulu, a large number of biogeographers persistently defended the idea of a Polynesian continent, agreeing at least only on wide land bridges between the now completely isolated islands. This whole area was formerly the mainland, which subsequently divided into numerous groups of islands; The Hawaiian Islands were the first to secede. Deep drilling in the Central Pacific atolls has found typical land snails at various epochal levels up to the Miocene at least (eg at 251 and 552 m).
The "island steps" that existed in ancient times, which are still found today, contributed to the migration of individual species from island to island. The Galapagos Islands rise at the intersection of the East Pacific Rise and short secondary ridges leading to Central and South America.
The Swedish botanist Scottsberg devoted his life to studying the flora of the Pacific Islands; on the basis of observational data, he came to the conclusion that once there was a Pacific flora, autochthonous (local), mainland, not associated either with the flora of North America or with the flora of any other neighboring continent.
The existing landforms in the area of New Guinea, New Zealand, the Philippine Islands and the Fiji Islands are good evidence of the existence of connections between the continents (this includes shallow underwater ridges and platforms); in addition, there are good geological data.
The theory of the existence of a mainland bridge or isthmus is well suited to explain the marginal migrations throughout the periphery of the Pacific Ocean through the Aleutian Islands to the Bering Strait, through the Antilles and from South America to Australia and New Zealand. Geotectonics in most cases is not in conflict with the presence of such relationships. When explaining migration along the transantarctic line, two serious questions arise: the area between the Ross Sea and New Zealand. The tectonic structures of South America, extending through the Scotia arc, connect with the Mesozoic folds of West Antarctica, but then abruptly break off at the Ross Sea. From the Ross Sea to New Zealand or Australia, not a single ridge departs. Here, apparently, the separation of the bark took place;
Geographical position. The Pacific (or Great) Ocean is a unique natural object of our planet in terms of size and features of nature. The ocean is located in all hemispheres of the Earth, between the continents of Eurasia and Australia in the west, North and South America in the east and Antarctica in the south.
The Pacific Ocean occupies more than 1/3 of the planet's surface and almost half of the World Ocean (Table VII.3). It has an oval outline, is somewhat elongated from the northwest to the southeast, and is widest between the tropics. The coastline is relatively straight off the coasts of North and South America and is highly indented off the coasts of Eurasia. The Pacific Ocean includes a number of marginal seas of East and Southeast Asia. There are a large number of archipelagos and individual islands in the ocean, which are studied as part of Oceania.
Table VII.3
General information about the oceans
Oceans Area, million km3 Volume,
million km3 Medium
depth, m
depth, m World Ocean 361.10 1340.74 3700 11022 (Marian Trench) Pacific 178.62 710.36 3980 11022 (Marian Trench) Atlantic 91.56 329.66 3600 8142 (Puerto Rico Trench) Indian 16.17 2 82 ,65 3710 7729 (Zonda Trench) Arctic
14,75
18,07
1220
5527 (Greenland Sea)
Bottom relief. The Pacific Ocean is the deepest. Its bottom relief is complex. The shelf (continental shallow) occupies a relatively small area. Off the coast of North and South America, its width does not exceed tens of kilometers, and off the coast of Eurasia, the shelf is measured in hundreds of kilometers. Deep-sea trenches are located in the marginal parts of the ocean, and the main part of the deep-sea trenches of the entire World Ocean is located in the Pacific Ocean: 25 out of 35 have a depth of more than 5 km; and all trenches with a depth of more than 10 km - there are 4 of them. Large uplifts of the bottom, individual mountains and ridges divide the ocean floor into basins. In the southeast of the ocean, the East Pacific Rise is located, which is part of the global system of mid-ocean ridges.
An almost continuous chain of active volcanoes is connected with the system of deep-sea trenches and mountain structures on the continents and islands adjacent to the ocean, forming the Pacific “Ring of Fire”. Ground and underwater earthquakes are also frequent in this zone, causing giant waves - tsunamis.
Climate. The Pacific Ocean stretches from subarctic to subantarctic latitudes, that is, it is located in almost all climatic zones of the Earth. Its main part is located in the equatorial, subequatorial and tropical zones of both hemispheres. The air temperature over the water area of these latitudes is from +16 to +24°С throughout the year. However, in the north of the ocean in winter it drops below 0°C. Near the coasts of Antarctica, this temperature is maintained even in the summer months.
The circulation of the atmosphere over the ocean is characterized by zonal features: westerly winds prevail in temperate latitudes, trade winds dominate in tropical latitudes, and monsoons are pronounced in subequatorial latitudes off the coast of Eurasia. Strong storm-force winds and tropical cyclones - typhoons are frequent over the Pacific Ocean. The maximum amount of precipitation falls in the western parts of the equatorial belt (about 3000 mm), the minimum - in the eastern regions of the ocean between the equator and the southern tropic (about 100 mm).
currents. The Pacific Ocean is quite strongly elongated from west to east and therefore latitudinal water flows predominate in it. Two huge rings of water movement are formed in the ocean: northern and southern. The Northern Ring includes the North Trade Wind, Kuroshio, North Pacific and California currents. The southern ring is made up of the South Equatorial, East Australian, Western Winds Current and Peruvian Current. Currents have a significant impact on the redistribution of heat in the ocean and on the nature of adjacent continents. Thus, trade wind currents drive warm waters from the western tropical coasts of the continents to the eastern ones, therefore, at low latitudes, the western part of the ocean is much warmer than the eastern one. In middle high latitudes, on the contrary, the eastern parts of the ocean are warmer than the western ones.
Water properties. All types of surface water masses are formed in the Pacific Ocean, except for the Arctic ones. Due to the ocean's large area between the tropics, its surface waters are warmer than other oceans. The average annual water temperature between the tropics is +19°C, in equatorial latitudes - from +25 to +29°C, off the coast of Antarctica - drops to -1°C. Precipitation falling over the ocean generally dominates evaporation. The salinity of the surface waters of the Pacific Ocean is slightly lower than in the Atlantic, since the western part of the ocean receives a lot of fresh river water (Amur, Yellow River, Yangtze, Mekong and others). Ice phenomena in the northern part of the ocean and in the subantarctic belt are seasonal. Off the coast of Antarctica, sea ice persists throughout the year. Antarctic icebergs with surface currents rise to 40°S.
organic world. In terms of biomass and number of species, the organic world of the Pacific Ocean is richer than in other oceans. This is due to its long geological history, huge size, variety of environmental conditions. Organic life is especially rich in equatorial-tropical latitudes, in areas where coral reefs develop. In the northern part of the ocean, there are many different types of salmon fish.
Fishing in the Pacific Ocean accounts for more than 45% of the world's catch. The main fishing areas are areas of interaction between warm and cold waters; shelf areas in the west of the ocean and areas of deep water rise off the coast of North, and especially South, America.
natural complexes. In the Pacific Ocean there are all natural belts, except for the north polar one.
The northern polar belt occupies a small part of the Bering and Okhotsk seas. In this belt, there is an intensive circulation of water, so they are rich in fish. The northern temperate zone occupies vast water areas. It is characterized by the interaction of warm and cold water masses. This contributes to the development of the organic world. In the west of the belt, a unique aquatic complex of the Sea of Japan is formed, which is distinguished by a large species diversity.
The northern subtropical belt in the Pacific Ocean is not as pronounced as the temperate one. The western part of the belt is warm, the eastern part is relatively cold. The waters are slightly mixed, blue, transparent. The number of plankton and fish species is low.
The Northern Tropical Belt is formed under the influence of the powerful Northern Tradewind Current. There are many separate islands and archipelagos in this belt. The productivity of the belt's waters is low. However, near the underwater heights and islands, where the vertical movement of the waters increases, accumulations of fish and other marine organisms appear.
In the equatorial belt, there is a complex interaction of winds and various currents. At the boundaries of flows, eddies and gyres contribute to the rise of waters, therefore their biological productivity increases. Aquatic complexes near the Sunda Islands and the shores of Northeast Australia, as well as coral reef complexes, are the richest in life.
In the southern hemisphere in the Pacific Ocean, similar natural belts are formed as in the northern hemisphere, but they differ in some properties of water masses and the composition of organisms. For example, notothenia and white-blooded fish live in the waters of the subantarctic and antarctic belts. In the southern tropical zone between 4 and 23 ° S.l. a special aquatic complex is being formed off the coast of South America. It is characterized by a steady and intensive rise of deep waters (upwelling), the active development of organic life. This is one of the most productive areas of the entire oceans.
Economic use. The Pacific Ocean and its seas wash the coasts of the continents, on which there are more than 30 coastal states with a total population of about 2 billion people. The main types of natural resources of the ocean are its biological resources. Ocean waters are characterized by high productivity (about 200 kg/km2). In recent years, the Pacific Ocean has ranked first in the world in terms of fish and seafood production. Mining began on the ocean shelf: deposits of oil and gas, tin ores and other non-ferrous metals; from sea water, table and potassium salts, magnesium, and bromine are obtained. World and regional shipping routes pass through the Pacific Ocean, and a large number of ports are located on the ocean shores. The most important lines run from the shores of North America to the Far East shores of Asia. The energy resources of the Pacific waters are large and varied, but are still underused.
Human economic activity has led to severe pollution of some areas of the Pacific Ocean. This was especially evident off the coast of Japan and North America. Depleted stocks of whales, a number valuable species fish and other animals. Some of them have lost their former commercial value.
§ 8. Atlantic Ocean
Geographical position. The Atlantic Ocean stretches from north to south for 16,000 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 bounded 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 ocean in the world. The coastline of the ocean in the northern hemisphere is heavily dissected by numerous peninsulas and bays. There are many islands, inland and marginal seas near the continents. The Atlantic consists of 13 seas, which occupy 11% of its area.
Bottom relief. The Mid-Atlantic Ridge runs through the entire ocean (at about an equal distance from the coasts of the continents). 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 6 to 30 km wide and up to 2 km deep. Both underwater active volcanoes and 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 uplifts. The shelf area in the Atlantic Ocean is larger than in the Pacific.
Mineral resources. Oil and gas reserves have been discovered on the shelf of the North Sea, in the Gulf of Mexico, Guinea and Biscay. Phosphorite deposits have been discovered in the area of deep water rise 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 found on the shelf in the sediments of ancient and modern rivers. Ferromanganese nodules have been found in bottom basins off the coasts of Florida and Newfoundland.
Climate. The Atlantic Ocean is located in all climatic zones of the Earth. The main part of the ocean area is between 40°N. and 42° S - is located in subtropical, tropical, subequatorial and equatorial climatic zones. There are high positive air temperatures all year round. The most severe climate is in the subantarctic and antarctic latitudes, and to a lesser extent in the subpolar, northern latitudes.
currents. In the Atlantic, as in the Pacific, two rings of surface currents are formed. In the northern hemisphere, the North Equatorial Current, the Gulf Stream, the North Atlantic and Canary Currents form the movement of waters in a clockwise direction. In the southern hemisphere, the South Trade Winds, the Brazilian, the West Winds and the Benguela move the waters counterclockwise. Due to the considerable length of the Atlantic Ocean from north to south, meridional water flows are more developed in it than latitudinal ones.
Water properties. The zonality 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, the isotherms near the coast deviate sharply from the latitudinal direction.
The northern half of the ocean is warmer than the southern one, the temperature difference reaches 6°С. 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 ices 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 again, but is transferred to neighboring continents (due to the relative narrowness of the ocean).
A lot of water flows into the Atlantic Ocean and its seas. big rivers: Amazon, Congo, Mississippi, Nile, Danube, La Plata, etc. They carry huge masses of fresh water, suspended material and pollutants into the ocean. In desalinated bays and seas of subpolar and temperate latitudes, ice forms near the western shores of the ocean in winter. Numerous icebergs and floating sea ice hinder navigation in the North Atlantic Ocean.
organic world. The Atlantic Ocean is poorer in species in the composition of flora and fauna than the Pacific. One of the reasons for this is its relative geological youth and a noticeable cooling in the Quaternary period during the glaciation of the northern hemisphere. However, in quantitative terms, the ocean is rich in organisms - it is the most productive per unit area. This is primarily due to the wide development of shelves and shallow banks, which are inhabited by many demersal and bottom fish (cod, flounder, perch, etc.). biological resources The Atlantic Ocean in many areas is depleted. The share of the ocean in world fisheries has declined significantly in recent years.
natural complexes. In the Atlantic Ocean, all zonal complexes are distinguished - natural belts, except for the northern polar one. The waters of the northern subpolar belt are rich in life. It is especially developed on the shelves off the coasts of Iceland, Greenland and the Labrador Peninsula. The temperate zone is characterized by intense interaction between cold and warm waters, its waters are the most productive areas of the Atlantic. The vast expanses of warm waters of the two subtropical, two tropical and equatorial zones are less productive than the waters of the northern temperate zone.
In the northern subtropical zone, a special natural aquatic complex of the Sargasso Sea stands out. It is characterized by high water salinity (up to 37.5 ppm) and low bioproductivity. Brown algae grow in clear, pure blue water - sargasso, which gave the name to the water area.
In the temperate zone of the southern hemisphere, as in the northern one, natural complexes are rich in life in areas where waters with different temperatures and water densities mix. In the subantarctic and antarctic belts, the manifestation of seasonal and permanent ice phenomena is characteristic, which affects the composition of the fauna (krill, cetaceans, notothenia fish).
Economic use. All types of human economic activity in marine areas are represented in the Atlantic Ocean. Among them, maritime transport is of the greatest importance, then - underwater oil and gas production, only then - the catch and use of biological resources.
More than 70 coastal countries with a population of over 1.3 billion people are located on the shores of the Atlantic. Many transoceanic routes pass through the ocean with large volumes of freight and passenger traffic. On the coasts of the ocean and its seas, the most significant ports of the world in terms of cargo turnover are located.
The already explored mineral resources of the ocean are significant (examples are given above). However, 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 an economic upswing due to their extraction (England, Norway, the Netherlands, Mexico, etc.).
The biological resources of the ocean have long been intensively used. However, due to the overfishing of a number of valuable commercial fish species, in recent years the Atlantic has yielded to the Pacific Ocean in terms of fish and seafood.
Intensive human economic activity in the waters of the Atlantic Ocean and its seas causes a noticeable deterioration of the natural environment - both in the ocean (water and air pollution, a decrease in the stocks of commercial fish species) and on the coasts. In particular, recreational conditions on the ocean coast are deteriorating. In order to prevent further and reduce the 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.
The Pacific Ocean is the largest ocean in terms of area and depth on Earth. It is located between the continents of Eurasia and Australia in the west, North and South America in the east, Antarctica in the south.
- Area: 179.7 million km²
- Volume: 710.4 million km³
- Maximum depth: 10,994 m
- Average depth: 3984 m
The Pacific Ocean stretches approximately 15.8 thousand km from north to south and 19.5 thousand km from east to west. Square with seas
179.7 million km², average depth - 3984 m, water volume - 723.7 million km³ (without seas, respectively: 165.2 million km², 4282 m and 707.6 million km³). The greatest depth of the Pacific Ocean (and the entire World Ocean) is 10,994 m (in the Mariana Trench). The international date line runs through the Pacific Ocean along the 180th meridian.
Etymology
The first European to see the ocean was the Spanish conquistador Balboa. In 1513, he and his companions crossed the Isthmus of Panama and came to the shore of an unknown ocean. Since they reached the ocean in a bay open to the south, Balboa called it the South Sea (Spanish: Mar del Sur). On November 28, 1520, Ferdinand Magellan entered the open ocean. He crossed the ocean from Tierra del Fuego to the Philippine Islands in 3 months and 20 days. All this time the weather was calm, and Magellan called it the Pacific Ocean. In 1753, the French geographer Jean-Nicolas Buache proposed calling it the Great Ocean as the largest of the oceans. But this name has not received universal recognition, and the name Pacific Ocean remains dominant in world geography. In English-speaking countries, the ocean is called English. pacific ocean.
Until 1917, the name Eastern Ocean was used on Russian maps, which was preserved by tradition from the time when Russian explorers entered the ocean.
Asteroid (224) Oceana is named after the Pacific Ocean.
Physical and geographical characteristics
General information
Occupying 49.5% of the surface of the World Ocean and containing 53% of its water volume, the Pacific Ocean is the largest ocean on the planet. From east to west, the ocean stretches for more than 19,000 km and 16,000 from north to south. Its waters are located mostly in the southern latitudes, less - in the northern ones. 
In 1951, an English expedition on the research ship Challenger recorded a maximum depth of 10,863 meters using an echo sounder. According to the results of measurements carried out in 1957 during the 25th voyage of the Soviet research vessel Vityaz (headed by Alexei Dmitrievich Dobrovolsky), the maximum depth of the chute is 11,023 m (updated data, the depth was originally reported as 11,034 m). The difficulty of measuring is that the speed of sound in water depends on its properties, which are different at different depths, so these properties must also be determined at several horizons with special instruments (such as a barometer and thermometer), and in the depth value shown by the echo sounder , amended. Studies in 1995 showed that it is about 10,920 m, and studies in 2009 - that 10,971 m. The latest study in 2011 gives a value of 10,994 m with an accuracy of ± 40 m. ”(Eng. Challenger Deep) is further from sea level than Mount Chomolungma is above it.
With its eastern edge, the ocean washes the western coasts of North and South America, with its western edge it washes the eastern coasts of Australia and Eurasia, and from the south it washes Antarctica. The border with the Arctic Ocean is the line in the Bering Strait from Cape Dezhnev to Cape Prince of Wales. The border with the Atlantic Ocean is drawn from Cape Horn along the meridian 68 ° 04 'W. or the shortest distance from South America to the Antarctic Peninsula through the Drake Passage, from Ost Island to Cape Sternek. The border with the Indian Ocean passes: south of Australia - along the eastern border of the Bass Strait to the island of Tasmania, then along the meridian 146 ° 55 'E. to Antarctica; north of Australia - between the Andaman Sea and the Strait of Malacca, further along the southwestern coast of Sumatra, the Sunda Strait, the southern coast of Java, the southern borders of the Bali and Savu seas, the northern border of the Arafura Sea, the southwestern coast of New Guinea and the western border of the Torres Strait . Sometimes the southern part of the ocean, with a northern boundary of 35 ° S. sh. (on the basis of the circulation of water and the atmosphere) up to 60 ° S. sh. (according to the nature of the bottom topography), refer to Southern Ocean, which is not officially released.
Seas
The area of the seas, bays and straits of the Pacific Ocean is 31.64 million km² (18% of the total ocean area), the volume is 73.15 million km³ (10%). Most of the seas are located in the western part of the ocean along Eurasia: Bering, Okhotsk, Japanese, Inner Japanese, Yellow, East China, Philippine; seas between the islands of Southeast Asia: South China, Javanese, Sulu, Sulawesi, Bali, Flores, Savu, Banda, Seram, Halmahera, Moluccas; along the coast of Australia: New Guinea, Solomonovo, Coral, Fiji, Tasmanovo; Antarctica has seas (sometimes referred to as the Southern Ocean): D'Urville, Somov, Ross, Amundsen, Bellingshausen. There are no seas along North and South America, but there are large bays: Alaska, California, Panama. 
Islands
Several thousand islands scattered across the Pacific Ocean were formed by volcanic eruptions. Some of these islands were overgrown with corals, and eventually the islands again sank into the sea, leaving behind coral rings - atolls.
By the number (about 10 thousand) and the total area of the islands, the Pacific Ocean occupies the first place among the oceans. In the ocean are the second and third largest islands of the Earth: New Guinea (829.3 thousand km²) and Kalimantan (735.7 thousand km²); the largest group of islands: the Greater Sunda Islands (1485 thousand km², including the largest islands: Kalimantan, Sumatra, Sulawesi, Java, Banka). Other largest islands and archipelagos: New Guinea Islands (New Guinea, Kolepom), Japanese islands(Honshu, Hokkaido, Kyushu, Shikoku), Philippine Islands (Luzon, Mindanao, Samar, Negros, Palawan, Panay, Mindoro), New Zealand (South and North Islands), Lesser Sunda Islands (Timor, Sumbawa, Flores, Sumba), Sakhalin, Moluccas (Seram, Halmahera), Bismarck Archipelago (New Britain, New Ireland), Solomon Islands (Bougainville), Aleutian Islands, Taiwan, Hainan, Vancouver, Fiji Islands (Viti Levu), Hawaiian Islands (Hawaii), New Caledonia, Kodiak Archipelago, Kuril Islands, New Hebrides, Queen Charlotte Islands, Galapagos Islands, Wellington, St. Lawrence, Ryukyu Islands, Riesko, Nunivak, Santa Ines, D'Antrecasto Islands, Samoa Islands, Revilla Gigedo, Palmer Archipelago, Shantar Islands, Magdalena, Louisiade Archipelago, Linga Archipelago, Loyalty Islands, Karaginsky, Clarence, Nelson, Princess Royal, Hanover, Commander Islands.
History of ocean formation
During the disintegration of the Pangea procontinent in the Mesozoic era into Gondwana and Laurasia, the Panthalassa ocean surrounding it began to decrease in area. By the end of the Mesozoic, Gondwana and Laurasia separated, and as their parts diverge, the modern Pacific Ocean began to form. Within the Pacific Trench, four fully oceanic tectonic plates developed during the Jurassic: the Pacific, Kula, Farallon, and Phoenix. The northwestern Kula plate was moving under the eastern and southeastern margins of the Asian continent. The northeastern Farallon oceanic plate was moving under Alaska, Chukotka and under the western margin of North America. The southeastern Phoenix oceanic plate was subducting under the western margin of South America. In the Cretaceous, the southeastern Pacific oceanic plate moved under the eastern margin of the then united Australo-Antarctic continent, as a result of which the blocks that now form the New Zealand Plateau and the underwater heights of Lord Howe and Norfolk broke away from the mainland. In the Late Cretaceous, the split of the Australo-Antarctic continent began. The Australian plate separated and began to move towards the equator. At the same time, in the Oligocene, the Pacific Plate changed its direction to the northwest. In the Late Miocene, the Farallon Plate split into two: Cocos and Nazca. The Kula plate, moving to the northwest, completely submerged (together with the northern margin of the Pacific plate) under Eurasia and under the proto-Aleutian Trench. 
Movement today tectonic plates continues. The axis of this movement is the mid-ocean rift zones in the South Pacific and East Pacific uplifts. To the west of this zone is the most large stove the Pacific Ocean, which continues to move northwest at a speed of 6-10 cm per year, crawling under the Eurasian and Australian plates. To the west, the Pacific Plate is pushing the Philippine Plate northwest under the Eurasian Plate at a rate of 6-8 cm per year. To the east of the mid-ocean rift zone are located: in the northeast, the Juan de Fuca plate, crawling at a rate of 2-3 cm per year under the North American plate; in the central part, the Cocos plate is moving northeast under the Caribbean lithospheric plate at a rate of 6-7 cm per year; to the south is the Nazca plate, moving east, sinking under the South American plate at a rate of 4-6 cm per year.
Geological structure and bottom topography
Underwater margins of the continents
The underwater margins of the continents occupy 10% of the Pacific Ocean. The relief of the shelf shows features of transgressive plains with subaerial relict relief. Such forms are typical for underwater river valleys on the Yavan shelf and for the shelf of the Bering Sea. Ridge landforms formed by tidal currents are widespread on the Korean shelf and the shelf of the East China Sea. Various coral structures are common on the shelf of equatorial-tropical waters. Most of the Antarctic shelf lies at depths of more than 200 m, the surface is very dissected, underwater elevations of a tectonic nature alternate with deep depressions - grabens. The continental slope of North America is heavily dissected by submarine canyons. Large submarine canyons are known on the continental slope of the Bering Sea. The continental slope of Antarctica is distinguished by a large width, diversity and dissection of the relief. Along North America, the continental foot is distinguished by very large fans of turbidity flows, merging into a single sloping plain, bordering the continental slope with a wide strip. 
The underwater margin of New Zealand has a peculiar continental structure. Its area is 10 times the area of the islands themselves. This underwater New Zealand plateau consists of the flat-topped Campbell and Chatham uplifts and the Baunkee depression between them. On all sides it is bounded by the continental slope, bordered by the continental foot. This includes the Late Mesozoic submarine Lord Howe ridge.
transition zone
On the western margin of the Pacific Ocean there are transitional areas from the margins of the continents to the ocean floor: Aleutian, Kuril-Kamchatka, Japanese, East China, Indonesian-Philippines, Bonin-Marianskaya (with the deepest point of the ocean - the Mariana Trench, depth 11,022 m), Melanesian, Vityazevskaya, Tonga-Kermadekskaya, Macquarie. These transitional areas include deep sea trenches, marginal seas, bounded by island arcs. On the eastern outskirts there are transitional regions: Central American and Peru-Chile. They are expressed only by deep-sea trenches, and instead of island arcs, young rocky years of Central and South America stretch along the trenches.
All transitional areas are characterized by volcanism and high seismicity; they form the marginal Pacific belt of earthquakes and modern volcanism. Transitional areas on the western margin of the Pacific Ocean are located in the form of two echelons, the youngest areas in terms of the stage of development are located on the border with the ocean floor, and the more mature ones are separated from the ocean floor by island arcs and island land masses with the continental crust.
Mid-ocean ridges and ocean floor
11% of the area of the Pacific Ocean floor is occupied by mid-ocean ridges, represented by the South Pacific and East Pacific Rise. They are wide, slightly dissected hills. Lateral branches depart from the main system in the form of the Chilean uplift and the Galapagos rift zone. The system of mid-ocean ridges of the Pacific Ocean also includes the Gorda, Juan de Fuca and Explorer ridges in the northeast of the ocean. The mid-ocean ridges of the ocean are seismic belts with frequent surface earthquakes and active volcanic activity. Fresh lavas, metal-bearing sediments, usually associated with hydrotherms, have been found in the rift zone. 
The Pacific Rise system divides the bed of the Pacific Ocean into two unequal parts. The eastern part is less complex and shallower. Here, the Chilean uplift (rift zone) and the Nazca, Sala y Gomez, Carnegie and Coconut ridges are distinguished. These ranges divide the eastern part of the bed into the Guatemalan, Panama, Peruvian and Chilean basins. All of them are characterized by a complexly dissected hilly and mountainous bottom topography. In the area of the Galapagos Islands, a rift zone is distinguished.
The other part of the bed, which lies to the west of the Pacific Rise, occupies approximately 3/4 of the entire bed of the Pacific Ocean and has a very complex relief structure. Dozens of hills and underwater ridges divide the ocean floor into a large number of basins. The most significant ranges form a system of uplifts, arched in plan, starting in the west and ending in the southeast. The Hawaiian Ridge forms the first such arc, parallel to it, the Cartographers Mountains, Markus Necker, the underwater ridge of the Line Islands form the next arc, the arc ends with the underwater base of the Tuamotu Islands. The next arc consists of the submerged bases of the Marshall Islands, Kiribati, Tuvalu, and Samoa. The fourth arc includes the Caroline Islands and the underwater height of Kapingamarangi. The fifth arc consists of the southern group of the Caroline Islands and the Eauripik shaft. Some ridges and uplands differ in their strike from those listed above, these are the Imperial (North-Western) ridge, the uplands of Shatsky, Magellan, Hess, Manihiki. These uplands are distinguished by leveled summit surfaces and are covered with carbonate deposits of increased thickness from above.
There are active volcanoes in the Hawaiian Islands and the Samoa archipelago. Around 10,000 separate seamounts, mostly of volcanic origin, are scattered along the bed of the Pacific Ocean. Many of them are guyots. The tops of some guyots are at a depth of 2-2.5 thousand m, the average depth above them is about 1.3 thousand m. The vast majority of islands in the central and western parts of the Pacific Ocean are of coral origin. Almost all volcanic islands are fringed with coral structures.
The bed and mid-ocean ridges of the Pacific Ocean are characterized by fault zones, usually expressed in the relief as complexes of linearly oriented grabens and horsts. All fault zones have their own names: Surveyor, Mendocino, Murray, Clarion, Clipperton and others. The basins and uplifts of the Pacific Ocean floor are characterized by an oceanic-type crust with a sedimentary layer thickness of 1 km in the northeast to 3 km on the Shatsky Rise and with a basalt layer thickness of 5 km to 13 km. Mid-ocean ridges have a rift-type crust characterized by increased density. Ultramafic rocks are found here, and schists have been uplifted in the Eltanin fault zone. Subcontinental (Kuril Islands) and continental crust (Japanese Islands) were found under the island arcs.
Bottom sediments
The major rivers of Asia, such as the Amur, the Yellow River, the Yangtze, the Mekong and others, carry more than 1,767 million tons of sediment per year into the Pacific Ocean. This alluvium almost completely remains in the waters of the marginal seas and bays. The largest rivers in America - the Yukon, Colorado, Columbia, Fraser, Guayas and others - provide about 380 million tons of sediment per year, and 70-80% of the suspended material is carried out into the open ocean, which is facilitated by the insignificant width of the shelf. 
Red clays are widespread in the Pacific Ocean, especially in the northern hemisphere. This is due to the great depth of the ocean basins. In the Pacific Ocean, there are two belts (southern and northern) of siliceous diatom oozes, as well as a distinct equatorial belt of siliceous radiolarian deposits. Vast areas of the bottom of the southwestern ocean are occupied by coral-algal biogenic deposits. To the south of the equator, foraminiferal oozes are widespread. There are several fields of pteropod deposits in the Coral Sea. In the northern deepest part of the Pacific Ocean, as well as in the Southern and Peruvian basins, extensive fields of ferromanganese nodules are observed.
Climate
The climate of the Pacific Ocean is formed due to the zonal distribution of solar radiation and atmospheric circulation, as well as a powerful seasonal influence Asian mainland. Almost all climatic zones can be distinguished in the ocean. In the northern temperate zone in winter, the baric center is the Aleutian minimum of pressure, which is weakly expressed in summer. To the south is the North Pacific High. Along the equator there is an Equatorial depression (area reduced pressure), which is replaced by the South Pacific High to the south. Further south, the pressure decreases again and then again gives way to a high pressure area over Antarctica. The direction of the wind is formed in accordance with the location of baric centers. In the temperate latitudes of the northern hemisphere, strong westerly winds prevail in winter, and weak southerly winds in summer. In the northwest of the ocean, north and northeast monsoon winds are established in winter, which are replaced by south monsoons in summer. Cyclones that occur on the polar fronts determine the high frequency of storm winds in the temperate and circumpolar zones (especially in the southern hemisphere). In the subtropics and tropics of the northern hemisphere, the northeast trade winds dominate. In the equatorial zone, mostly calm weather is observed all year round. In the tropical and subtropical zones of the southern hemisphere, a steady southeast trade wind dominates, strong in winter and weak in summer. Violent tropical hurricanes, here called typhoons, are born in the tropics (mainly in summer). They usually arise east of the Philippines, from where they move northwest and north through Taiwan, Japan and fade on the approaches to the Bering Sea. Another area where typhoons originate is the coastal regions of the Pacific Ocean adjacent to Central America. In the fortieth latitudes of the southern hemisphere, strong and constant westerly winds are observed. In the high latitudes of the southern hemisphere, the winds are subject to the general cyclonic circulation characteristic of the sub-Antarctic region of low pressure. 
The distribution of air temperature over the ocean is subordinated to the general latitudinal zonality, but the western part has a warmer climate than the eastern part. In the tropical and equatorial zones, average air temperatures from 27.5 °C to 25.5 °C prevail. During the summer, the 25°C isotherm widens northward in the western part of the ocean and only slightly in the eastern, and strongly shifts northward in the southern hemisphere. Passing over the vast expanses of the ocean, the air masses are intensively saturated with moisture. On both sides of the equator in the near-equatorial zone, two narrow bands of maximum precipitation are noted, outlined by an isohyet of 2000 mm, and a relatively arid zone is expressed along the equator. In the Pacific Ocean, there is no zone of convergence of the northern trade winds with the southern ones. There are two independent zones with excessive moisture and a relatively dry zone separating them. To the east, in the equatorial and tropical zones, the amount of precipitation decreases. The most arid regions in the northern hemisphere are adjacent to California, in the southern - to the Peruvian and Chilean basins (coastal regions receive less than 50 mm of precipitation per year).
Hydrological regime
Surface water circulation
The general scheme of the currents of the Pacific Ocean is determined by the laws of the general circulation of the atmosphere. The northeast trade wind of the northern hemisphere contributes to the emergence of the Northeast Trade Wind, which crosses the ocean from the Central American coast to the Philippine Islands. Further, the current is divided into two branches: one deviates to the south and partly feeds the Equatorial countercurrent, and partly spreads over the basins of the Indonesian seas. The northern branch follows the East China Sea and, leaving it south of the island of Kyushu, gives rise to a powerful warm current Kuroshio. This current follows north to the coast of Japan, having a noticeable effect on the climate of the Japanese coast. At 40° N. sh. The Kuroshio flows into the North Pacific Current, following east to the Oregon coast. Colliding with North America, it is divided into the northern branch of the warm Alaska Current (passing along the mainland to the Alaska Peninsula) and the southern branch of the cold California Current (along the California Peninsula, flowing into the Northeast Current, closing the circle). In the southern hemisphere, the Southeast Trade Wind forms the South Trade Wind Current, which crosses the Pacific Ocean from the coast of Colombia to the Moluccas. Between the Line and Tuamotu Islands, it forms a branch that follows the Coral Sea and further south along the coast of Australia, forming the East Australian Current. The main masses of the South Equatorial Current east of the Moluccas merge with the southern branch of the North Equatorial Current and together form the Equatorial Countercurrent. The East Australian Current flows south of New Zealand into the powerful Antarctic Circumpolar Current, which flows from the Indian Ocean and crosses the Pacific Ocean from west to east. At the southern end of South America, this current branches off to the north in the form of the Peruvian Current, which in the tropics joins the South Equatorial Current, completing the southern circle of currents. Another branch of the current of the West winds goes around South America under the name of the current of Cape Horn and goes into the Atlantic Ocean. An important role in the circulation of the waters of the Pacific Ocean belongs to the cold subsurface Cromwell Current, which flows under the South Trade Wind Current from 154° W. to the area of the Galapagos Islands. In summer, El Niño is observed in the eastern equatorial part of the ocean, when a warm, slightly saline current pushes the cold Peruvian current away from the coast of South America. At the same time, the supply of oxygen to the subsurface layers is stopped, which leads to the death of plankton, fish and birds that feed on them, and heavy rains fall on the usually dry coast, causing catastrophic floods. 
Salinity, ice formation
Tropical zones have the maximum salinity (up to a maximum of 35.5-35.6 ‰), where the intensity of evaporation is combined with a relatively small amount of precipitation. To the east, under the influence of cold currents, salinity decreases. A large amount of precipitation also lowers salinity, especially at the equator and in the western circulation zones of temperate and subpolar latitudes.
Ice in the south of the Pacific Ocean is formed in the Antarctic regions, and in the north - only in the Bering, Okhotsk and partially in the Sea of Japan. From the shores of southern Alaska, a certain amount of ice is dumped in the form of icebergs, which in March - April reach 48-42 ° N. sh. The northern seas, especially the Bering Sea, supply almost the entire mass of floating ice in the northern regions of the ocean. In Antarctic waters, the limit of pack ice reaches 60-63°S. latitude, icebergs spread far to the north, up to 45 ° N. sh.
water masses
In the Pacific Ocean, surface, subsurface, intermediate, deep and bottom water masses are distinguished. The surface water mass has a thickness of 35-100 m and is distinguished by the relative uniformity of temperatures, salinity and density, which is especially characteristic of tropical waters, and the variability of characteristics due to the seasonality of climatic phenomena. This water mass is determined by heat transfer at the ocean surface, the ratio of precipitation and evaporation, and intense mixing. The same, but to a lesser extent, applies to subsurface water masses. In the subtropics and cold latitudes, these water masses are surface for half a year, and subsurface for half a year. in different climatic zones their boundary with intermediate waters ranges between 220 and 600 m. Subsurface waters are distinguished by increased salinity and density, with temperatures ranging from 13-18 ° C (in the tropics and subtropics) to 6-13 ° C (in the temperate zone). Subsurface water in warm climates is formed by sinking more saline surface water. 
Intermediate water masses of temperate and high latitudes have a temperature of 3-5 ° C and a salinity of 33.8-34.7 ‰. The lower boundary of the intermediate masses is at a depth of 900 to 1700 m. Deep water masses are formed as a result of the submergence of cooled waters in the Antarctic waters and the waters of the Bering Sea and their subsequent spreading over the basins. Bottom masses of water are located at depths of more than 2500-3000 m. They are characterized by low temperature (1-2 ° C) and salinity uniformity (34.6-34.7 ‰). These waters are formed on the Antarctic shelf under conditions of strong cooling. Gradually, they spread along the bottom, fill all the depressions and penetrate through the transverse passages in the mid-ocean ridges into the Southern and Peruvian, and then into the northern basins. Compared to the bottom waters of other oceans and the South Pacific, the bottom water masses of the northern basins of the Pacific Ocean are characterized by a reduced content of dissolved oxygen. Bottom waters, together with deep waters, make up 75% of the total volume of Pacific Ocean waters.
Flora and fauna
The Pacific Ocean accounts for more than 50% of the total biomass of the World Ocean. Life in the ocean is abundant and varied, especially in the tropical and subtropical zones between the coasts of Asia and Australia, where vast areas are occupied by coral reefs and mangroves. The phytoplankton of the Pacific Ocean mainly consists of microscopic unicellular algae, numbering about 1300 species. About half of the species belong to the peridineans and somewhat less to the diatoms. In shallow water areas and in upwelling zones, most of the vegetation is concentrated. The bottom vegetation of the Pacific Ocean has about 4 thousand species of algae and up to 29 species of flowering plants. In the temperate and cold regions of the Pacific Ocean, brown algae are massively distributed, especially from the kelp group, and in the southern hemisphere there are giants from this family up to 200 m long. Fucus, large green and well-known red algae, which, along with coral polyps, are especially common reef-building organisms. 
The fauna of the Pacific Ocean is 3-4 times richer in species composition than in other oceans, especially in tropical waters. In the Indonesian seas, more than 2 thousand species of fish are known, in the northern seas there are only about 300 of them. In the tropical zone of the ocean there are more than 6 thousand species of mollusks, and in the Bering Sea there are about 200 of them. For the fauna of the Pacific Ocean, the antiquity of many systematic groups and endemism. A large number of ancient species of sea urchins live here, primitive genera of horseshoe crabs, some very ancient fish that have not been preserved in other oceans (for example, Jordan, Gilbertidia); 95% of all salmon species live in the Pacific Ocean. Endemic species of mammals: dugong, fur seal, sea lion, sea otter. Gigantism is characteristic of many species of the fauna of the Pacific Ocean. In the northern part of the ocean, giant mussels and oysters are known; in the equatorial zone, the largest bivalve mollusk, the tridacna, lives, weighing up to 300 kg. In the Pacific Ocean, the ultra-abyssal fauna is most clearly represented. Under conditions of enormous pressure, low water temperature at a depth of more than 8.5 km, about 45 species live, of which more than 70% are endemic. Among these species, holothurians predominate, leading a very sedentary lifestyle and capable of passing through the gastrointestinal tract great amount soil, the only source of nutrition at these depths. 
Ecological problems
Human economic activity in the Pacific Ocean has led to the pollution of its waters, to the depletion of biological wealth. So, by the end of the 18th century, sea cows in the Bering Sea were completely exterminated. At the beginning of the 20th century, northern fur seals and some species of whales were on the verge of extinction, now their fishing is limited. A great danger in the ocean is the pollution of waters with oil and oil products (the main pollutants), some heavy metals, and waste from the nuclear industry. Harmful substances are carried by currents throughout the ocean. Even off the coast of Antarctica, these substances have been found in the composition of marine organisms. Ten US states are constantly dumping their waste into the sea. In 1980, more than 160,000 tons of waste were destroyed in this way, since then this figure has decreased. 
The Great Pacific Garbage Patch of plastic and other waste has formed in the North Pacific Ocean, formed by ocean currents, gradually concentrating garbage thrown into the ocean in one area thanks to the North Pacific Current System. This slick stretches across the North Pacific Ocean from a point about 500 nautical miles off the coast of California, past Hawaii, and narrowly misses Japan. In 2001, the mass of the garbage island was more than 3.5 million tons, and the area was more than 1 million km², which was six times the mass of zooplankton. Every 10 years, the landfill area increases by an order of magnitude.
On August 6 and 9, 1945, the US military carried out atomic bombings of the Japanese cities of Hiroshima and Nagasaki - the only two examples of the combat use of nuclear weapons in the history of mankind. The total death toll ranged from 90 to 166 thousand people in Hiroshima and from 60 to 80 thousand people in Nagasaki. From 1946 to 1958, the United States of America carried out nuclear tests on the Bikini and Eniwetok atolls (Marshall Islands). A total of 67 explosions of atomic and hydrogen bombs were carried out. On March 1, 1954, during a surface test of a 15 megaton hydrogen bomb, the explosion produced a crater 2 km in diameter and 75 m deep, a mushroom cloud 15 km high and 20 km in diameter. As a result, Bikini Atoll was destroyed, and the territory was subjected to the largest radioactive contamination in US history and exposure of local residents. In 1957-1958, the UK carried out 9 atmospheric nuclear tests at the Christmas and Malden atolls (Line Islands) in Polynesia. In 1966-1996, France carried out 193 nuclear tests (including 46 in the atmosphere, 147 underground) on the atolls of Mururoa and Fangataufa (Tuamotu Archipelago) in French Polynesia. 
On March 23, 1989, the Exxon Valdez tanker, owned by ExxonMobil (USA), crashed off the coast of Alaska. As a result of the disaster, about 260,000 barrels of oil spilled into the sea, forming a slick of 28,000 km². About 2,000 kilometers of coastline were polluted with oil. This accident was considered the largest environmental disaster that has ever occurred at sea (up to the accident of the DH drilling rig in the Gulf of Mexico on April 20, 2010).
Pacific coast states
States along the borders of the Pacific Ocean (clockwise):
- USA,
- Canada,
- United Mexican States,
- Guatemala,
- El Salvador,
- Honduras,
- Nicaragua,
- Costa Rica,
- Panama,
- Colombia,
- Ecuador,
- Peru,
- Chile,
- Australian Union,
- Indonesia,
- Malaysia,
- Singapore,
- Brunei Darussalam,
- Philippines,
- Thailand,
- Cambodia,
- Socialist Republic of Vietnam,
- People's Republic Of China,
- The Republic of Korea,
- Democratic People's Republic of Korea,
- Japan,
- Russian Federation.
Directly on the oceanic expanses are island states and possessions of states that are not part of the region, forming Oceania:
Melanesia:
- Vanuatu,
- New Caledonia (France),
- Papua New Guinea,
- Solomon islands,
- Fiji;
micronesia:
- Guam (USA),
- Kiribati,
- Marshall Islands,
- Nauru,
- Palau,
- Northern Mariana Islands (USA),
- Wake Atoll (USA)
- Federated States of Micronesia;
Polynesia:
- Eastern Samoa (USA),
- New Zealand,
- Samoa,
- Tonga,
- Tuvalu,
- Pitcairn (UK)
- Wallis and Futuna (France)
- French Polynesia (France).
History of Pacific exploration
The study and development of the Pacific Ocean began long before the appearance of a written history of mankind. Junks, catamarans and simple rafts were used to navigate the ocean. The expedition of 1947 on a raft of balsa logs "Kon-Tiki" under the leadership of the Norwegian Thor Heyerdahl proved the possibility of crossing the Pacific Ocean in a westerly direction from central South America to the islands of Polynesia. Chinese junks made trips along the ocean coast to the Indian Ocean (for example, Zheng He's seven voyages in 1405-1433). 
The first European to see the Pacific Ocean was the Spanish conquistador Vasco Nunez de Balboa, who in 1513, from one of the peaks of the mountain range on the Isthmus of Panama, “in silence” saw the boundless water surface of the Pacific Ocean stretching to the south and dubbed it the South Sea. In the autumn of 1520, the Portuguese navigator Ferdinand Magellan circled South America, breaking the strait, after which he saw new expanses of water. During the further transition from Tierra del Fuego to the Philippine Islands, which took more than three months, the expedition did not encounter a single storm, which is obviously why Magellan called the Pacific Ocean. The first detailed map of the Pacific Ocean was published by Ortelius in 1589. As a result of the expedition of 1642-1644 under the command of Tasman, it was proved that Australia is a separate mainland.
Active exploration of the ocean began in the 18th century. The leading states of Europe began to send research expeditions to the Pacific Ocean, led by navigators: the Englishman James Cook (exploration of Australia and New Zealand, the discovery of many islands, including Hawaii), the French Louis Antoine Bougainville (exploration of the islands of Oceania) and Jean-Francois La Perouse , Italian Alessandro Malaspina (mapped the entire western coast of South and North America from Cape Horn to the Gulf of Alaska). The northern part of the ocean was explored by Russian explorers S. I. Dezhnev (discovery of the strait between Eurasia and North America), V. Bering (exploration of the northern shores of the ocean) and A. I. Chirikov (exploration of the northwestern coast of North America, the northern part of the Pacific Ocean and northeast coast of Asia). During the period from 1803 to 1864, Russian sailors completed 45 round-the-world and semi-circumnavigation voyages, as a result of which the Russian military and commercial fleet mastered the sea route from Baltic Sea to the Pacific Ocean and along the way discovered several islands in the ocean. During the round-the-world expedition of 1819-1821, under the leadership of F.F. Bellingshausen and M.P. Lazarev, Antarctica was discovered along with 29 islands of the Southern Ocean.
From 1872 to 1876, the first scientific ocean expedition took place on the English sailing-steam corvette Challenger, new data were obtained on the composition of the ocean waters, on the flora and fauna, on the bottom topography and soils, the first map of the depths of the ocean was compiled and the first collection was collected. deep sea animals. A round-the-world expedition on the Russian propeller-sailing corvette "Vityaz" of 1886-1889, led by oceanographer S. O. Makarov, explored the northern part of the Pacific Ocean in detail. The results of this expedition and all previous Russian and foreign expeditions, many round-the-world trips Makarov carefully studied and for the first time made a conclusion about the circular rotation and counterclockwise direction of surface currents in the Pacific Ocean. The result of the American expedition of 1883-1905 on the ship "Albatross" was the discovery of new types of living organisms and the laws of their development. A great contribution to the study of the Pacific Ocean was made by the German expedition on the ship Planet (1906-1907) and the American oceanographic expedition on the non-magnetic schooner Carnegie (1928-1929) led by the Norwegian X. W. Sverdrup. In 1949, a new Soviet research vessel "Vityaz" was launched under the flag of the USSR Academy of Sciences. Until 1979, the ship made 65 scientific voyages, as a result of which many "white spots" were closed on the maps of the underwater relief of the Pacific Ocean (in particular, the maximum depth in the Mariana Trench was measured). At the same time, research was carried out by expeditions of Great Britain - the Challenger II (1950-1952), Sweden - Albatross III (1947-1948), Denmark - Galatea (1950-1952) and many others, which brought a lot of new information about topography of the ocean floor, bottom sediments, life in the ocean, the physical characteristics of its waters. Within the framework of the International Geophysical Year (1957-1958), international forces (especially the USA and the USSR) carried out research, as a result of which new bathymetric and marine navigation charts of the Pacific Ocean were compiled. Since 1968, regular deep-water drilling, work on the movement of water masses at great depths, and biological research have been carried out on the American ship Glomar Challenger. On January 23, 1960, the first human dive was made to the bottom of the deepest trench in the World Ocean - the Mariana. On the Trieste research bathyscaphe, US Navy Lieutenant Don Walsh and explorer Jacques Picard descended there. On March 26, 2012, American director James Cameron on the Deepsea Challenger made the first solo and second-ever dive to the bottom of the Mariana Trench. The device stayed at the bottom of the depression for about six hours, during which samples of underwater soil, plants and living organisms were collected. Cameron's footage will form the basis of a National Geographic Channel science documentary.
In 1966-1974, the monograph "Pacific Ocean" was published in 13 volumes, published by the Institute of Oceanography of the USSR Academy of Sciences. In 1973, the Pacific Oceanological Institute named after V.I. V. I. Ilyichev, who carried out extensive studies of the Far Eastern seas and the open space of the Pacific Ocean. In recent decades, numerous measurements of the ocean have been carried out from space satellites. The result was a bathymetric atlas of the oceans released in 1994 by the US National Geophysical Data Center with a map resolution of 3-4 km and a depth accuracy of ±100 m.
Economic importance
At present, the coast and islands of the Pacific Ocean are developed and populated extremely unevenly. The largest centers of industrial development are the US coast (from the Los Angeles region to the San Francisco region), the coast of Japan and South Korea. The role of the ocean in the economic life of Australia and New Zealand is significant. The South Pacific is a "graveyard" of spacecraft. Here, far from shipping routes, decommissioned space objects are flooded. 
Fishing and marine industries
The temperate and tropical latitudes of the Pacific Ocean are of the greatest commercial importance. The Pacific Ocean accounts for about 60% of the world's fish catch. Among them are salmon (pink salmon, chum salmon, coho, sim), herring (anchovy, herring, sardine), cod (cod, pollock), perch (mackerel, tuna), flounder (flounder). Mammals are being hunted: sperm whale, minke whale, fur seal, sea otter, walrus, sea lion; invertebrates: crabs, shrimps, oysters, scallops, cephalopods. A number of plants are harvested (kelp (seaweed), anfeltia (agaronos), seagrass eelgrass and phyllospadix), processed into Food Industry and for medicine. The most productive fishery is carried out in the West-Central and North-Western parts of the Pacific Ocean. The largest fishing powers of the Pacific Ocean: Japan (Tokyo, Nagasaki, Shimonoseki), China (Zhoushan archipelago, Yantai, Qingdao, Dalian), Russian Federation (Primorye, Sakhalin, Kamchatka), Peru, Thailand, Indonesia, Philippines, Chile, Vietnam, South Korea, North Korea, Commonwealth of Australia, New Zealand, USA.
Transport routes
Important sea and air communications between the countries of the Pacific basin and transit routes between the countries of the Atlantic and Indian Oceans run through the Pacific Ocean. The most important ocean routes lead from Canada and the United States to Taiwan, China and the Philippines. The main navigable straits of the Pacific Ocean: Bering, Tatar, La Perouse, Korean, Taiwan, Singapore, Malacca, Sangar, Bass, Torres, Cook, Magellan. The Pacific Ocean is connected to the Atlantic Ocean by the artificial Panama Canal, dug between North and South America along the Isthmus of Panama. Major ports: Vladivostok (general cargo, oil products, fish and seafood, timber and lumber, scrap metal, ferrous and non-ferrous metals), Nakhodka (coal, oil products, containers, metal, scrap metal, refrigerated cargo), Vostochny, Vanino (coal, oil) ( Russia), Busan (Republic of Korea), Kobe-Osaka (oil and oil products, machinery and equipment, cars, metals and scrap metal), Tokyo-Yokohama (scrap metal, coal, cotton, grain, oil and oil products, rubber, chemicals, wool, machinery and equipment, textiles, automobiles, medicines), Nagoya (Japan), Tianjin, Qingdao, Ningbo, Shanghai (all types of dry, liquid and general cargo), Hong Kong (textiles, clothing, fiber, radio and electrical goods, plastic products, machinery, equipment), Kaohsiung, Shenzhen, Guangzhou (China), Ho Chi Minh City (Vietnam), Singapore (petroleum products, rubber, food, textiles, machinery and equipment) (Singapore), Klang (Malaysia), Jakarta (Indonesia), Manila (Philippines ), Sydney (general cargo, iron ore, coal, oil and oil products, grain), Newcastle, Melbourne (Australia), Auckland (New Zealand), Vancouver (timber cargo, coal, ores, oil and oil products, chemicals and general cargo) (Canada), San Francisco, Los Angeles (petroleum and oil products, copra, chemical cargoes, timber, grain, flour, canned meat and fish, citrus fruits, bananas, coffee, machinery and equipment, jute, cellulose), Auckland, Long Beach (USA), Colon (Panama), Huasco (ores, fish, fuel, food) (Chile). The Pacific Ocean has a significant number of relatively small multifunctional ports. 
Air transportation across the Pacific Ocean plays an important role. The first regular flight across the ocean was made in 1936 on the route San Francisco (USA) - Honolulu (Hawaii) - Manila (Philippines). Now the main transoceanic routes are laid through the northern and central regions of the Pacific Ocean. Airways are of great importance in domestic transportation and between the islands. In 1902, Great Britain laid the first underwater telegraph cable (12.55 thousand km long) along the ocean floor, passing through the Fanning and Fiji Islands, linking Canada, New Zealand, and the Commonwealth of Australia. Radio communication has been widely used for a long time. Now artificial earth satellites are used for communication across the Pacific Ocean, which significantly expands the capacity of communication channels between countries.
Minerals
The bottom of the Pacific Ocean hides rich deposits of various minerals. Oil and gas are produced on the shelves of China, Indonesia, Japan, Malaysia, the United States of America (Alaska), Ecuador (Guayaquil Bay), Australia (Bass Strait), and New Zealand. According to existing estimates, the subsoil of the Pacific Ocean contains up to 30-40% of all potential oil and gas reserves of the World Ocean. The largest producer of tin concentrates in the world is Malaysia, and Australia is the largest producer of zircon, ilmenite and others. The ocean is rich in ferromanganese nodules, with total surface reserves of up to 7 1012 tons. The most extensive reserves are observed in the northern deepest part of the Pacific Ocean, as well as in the South and Peruvian basins. In terms of the main ore elements, the nodules of the ocean contain manganese 7.1 1010 tons, nickel 2.3 109 tons, copper 1.5 109 tons, cobalt 1 109 tons. the Kuril Ridge and the Sakhalin Shelf in the Sea of Okhotsk, the Nankai Trench in the Sea of Japan and around the coast of Japan, in the Peru Depression. In 2013, Japan intends to begin pilot drilling to extract natural gas from methane hydrate deposits on the Pacific Ocean floor northeast of Tokyo.
Recreational resources
The recreational resources of the Pacific Ocean are characterized by considerable diversity. According to the World Tourism Organization, at the end of the 20th century, East Asia and the Pacific accounted for 16% of international tourist visits (by 2020, the share is projected to increase to 25%). The main countries of formation of outbound tourism in this region are Japan, China, Australia, Singapore, Republic of Korea, Russia, USA and Canada. Main recreational areas: Hawaiian Islands, the islands of Polynesia and Micronesia, the east coast of Australia, the Bohai Bay and Hainan Island in China, the coast of the Sea of Japan, areas of cities and urban agglomerations of the coast of North and South America. 
Among the countries with the largest flow of tourists (according to 2010 data from the World Tourism Organization) in the Asia-Pacific region, China (55 million visits per year), Malaysia (24 million), Hong Kong (20 million), Thailand (16 million), Macau (12 million), Singapore (9 million), Republic of Korea (9 million), Japan (9 million), Indonesia (7 million), Australia (6 million), Taiwan (6 million), Vietnam (5 million), Philippines (4 million), New Zealand (3 million), Cambodia (2 million), Guam (1 million); coastal countries of the Americas: USA (60 million), Mexico (22 million), Canada (16 million), Chile (3 million), Colombia (2 million), Costa Rica (2 million), Peru (2 million ), Panama (1 million), Guatemala (1 million), El Salvador (1 million), Ecuador (1 million).
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