In what part of the ocean is the Pacific Ocean. Pacific Ocean ~ Seas and Oceans

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 is assigned 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 the largest region of 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 mainland of Asia, 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 there are large seas: Bering, Okhotsk, Japan, Yellow, East China, South China, Sulawesi, Yavan, 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 water movements is one of the most important factors in the formation of the structure of waters and water masses in the Pacific Ocean.

In addition to these main natural features, the economic development of the ocean is strongly influenced by the 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 a total population of 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 domed profile, a considerable width (up to 2000 km), and a discontinuous strip of axial rift valleys with a wide participation of transverse fault zones in the formation of the topography. 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 at 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. Underwater ridges divide the eastern part of the ocean floor into a series of basins: Guatemalan (4199 m), Panama (4233 m), Peruvian (5660 m), Chilean (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. 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. An important distinguishing feature of the bottom sediments of the Pacific Ocean is the wide distribution of deep-water 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 coal are of greatest importance.

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. The United States, Japan, Indonesia, Peru, Chile, Brunei, Papua, Australia, New Zealand, Russia (in the region of Sakhalin Island) are producing oil and gas. 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.

It is believed that the first person to visit the Pacific Ocean on a ship was Magellan. In 1520, he circled South America and saw new expanses of water. Since Magellan's team did not meet a single storm during the entire journey, the new ocean was called " Quiet".

But even earlier in 1513 the Spaniard Vasco Nunez de Balboa headed south from Colombia to what he was told was a wealthy country with a large sea. Having reached the ocean, the conquistador saw an endless expanse of water stretching to the west, and called it " South Sea".

Fauna of the Pacific Ocean

The ocean is famous for its rich flora and fauna. About 100 thousand species of animals live in it. There is no such diversity in any other ocean. For example, the second largest ocean - Atlantic, is inhabited by "only" 30 thousand species of animals.

There are several places in the Pacific Ocean where the depth exceeds 10 km. These are the famous Mariana Trench, the Philippine Trench and the Kermadec and Tonga depressions. Scientists were able to describe 20 species of animals that live at such a great depth.

Half of all seafood consumed by humans is caught in the Pacific Ocean. Among 3,000 fish species, industrial-scale fishing is open for herring, anchovies, mackerels, sardines, etc.

Climate

The large extent of the ocean from north to south quite logically explains the diversity of climatic zones - from equatorial to Antarctic. The largest zone is the equatorial zone. Throughout the year, the temperature here does not fall below 20 degrees. Temperature fluctuations during the year are so small that we can safely say that it is always +25 there. There is a lot of precipitation, more than 3,000 mm. in year. Very frequent cyclones are characteristic.

The amount of precipitation is greater than the amount of evaporating water. Rivers, which bring more than 30,000 m³ of fresh water into the ocean every year, make surface water less saline than other oceans.

The relief of the bottom and islands of the Pacific Ocean

The bottom relief is extremely varied. Located in the east East Pacific Rise where the terrain is relatively flat. In the center are basins and deep-sea trenches. The average depth is 4,000 m, and in some places exceeds 7 km. The bottom of the center of the ocean is covered with products of volcanic activity with a high content of copper, nickel and cobalt. The thickness of such deposits in some areas can be 3 km. The age of these rocks begins with the Jurassic and Cretaceous period.

At the bottom there are several long chains of seamounts formed as a result of the action of volcanoes: mountains of the Emperor, Louisville and the Hawaiian islands. There are about 25,000 islands in the Pacific Ocean. That's more than all the other oceans combined. Most of them are located south of the equator.

Islands are classified into 4 types:

1. continental islands. Very closely related to the continents. Includes New Guinea, the islands of New Zealand and the Philippines;
2. high islands. Appeared as a result of eruptions of underwater volcanoes. Many of today's high islands have active volcanoes. For example, Bougainville, Hawaii and the Solomon Islands;
3. Coral raised atolls;

The last two types of islands are huge colonies of coral polyps that form coral reefs and islands.

• This ocean is so huge that its maximum width is equal to half the earth's equator, i.e. more than 17 thousand km.
• The animal world is large and varied. Even now, new animals unknown to science are regularly discovered there. So, in 2005, a group of scientists discovered about 1000 species of decapod cancer, two and a half thousand mollusks and more than a hundred crustaceans.
• The deepest point on the planet is in the Pacific Ocean in the Mariana Trench. Its depth exceeds 11 km.
• The highest mountain in the world is located in the Hawaiian Islands. It is called Muana Kea and is an extinct volcano. The height from the base to the top is about 10,000 m.
• At the bottom of the ocean is Pacific volcanic ring of fire, which is a chain of volcanoeslocated along the perimeter of the entire ocean.

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 zones, the number of species increases sharply, 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 the general nature of the distribution of temperature and salinity: near the equator 1.0215-1.0225 g/cm3, in the North - 1.0265 g/cm3 and more, in the South - 1.0275 g/cm3 and more. The color of the water in 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 predominates, 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 ° south latitude, in summer it shifts to 70 ° south latitude, icebergs are carried out to 46-48 ° south latitude at the end of summer. Icebergs form mainly in the Ross Sea.

A report on the Pacific Ocean for a geography lesson can be supplemented with interesting facts. Messages about the Pacific Ocean contains a lot of information.

Report on the topic "Pacific Ocean"

The Pacific Ocean got its name thanks to, which in 1521 crossed the Pacific Ocean from the western coast of South America to the shores of South Asia, and never got into a storm, which is why he called the ocean "Pacific".

The Pacific Ocean is called the Great Ocean for its size, as it is the largest body of water on Earth.

• This deepest and warmest in the surface layer of the ocean.
• The highest wind waves and the most destructive tropical hurricanes form here.
• He takes first place in the number of islands. The islands of the central part of the ocean are united under the common name Oceania.
• It occupies almost half the area of ​​the entire World Ocean and washes the shores of the five continents of the Earth.

Geographical position of the Pacific Ocean

The Pacific Ocean covers over 30% of the Earth's surface and surpasses all continents in area. It stretches for 16,000 km from north to south, and more than 19,000 km from west to east.

In the east, the boundaries of the ocean are the coasts of South and North America, the Drake Passage, in the west - the coasts of Asia, the Malacca Strait, the islands of Sumatra, Java, Lesser Sunda, New Guinea, Torres Strait, Tasmania Island, in the south the border runs conditionally along the line of the Antarctic convergence.

Average depth of the Pacific Ocean 3976 m, maximum 11,034 m (Marian Trench).

Volcanoes are common at the bottom of the Pacific Ocean. During the eruption of underwater volcanoes, islands are sometimes formed, many of which are short-lived and eroded by water.

The underwater relief of the vast ocean is diverse. At the bottom of the Pacific Ocean there are vast basins, and separate mountains, and elevations, and in the southern part there are two uplifts that form a mid-ocean ridge.

Climate of the Pacific

The climate of the ocean is varied and varies from equatorial to subarctic in the north and Antarctic in the south.

The widest part is located in hot zones. Therefore, the average temperature in the surface layer is 2 gr. higher than in the Atlantic and Indian Oceans.

The average salinity of the ocean is 34.5 ppm- this is lower than in other oceans, since more fresh water enters it with precipitation and rivers than evaporates.

The stretch of the ocean from the northern to the southern polar latitudes determines the climatic diversity in its spaces:

- Monsoons are typical for the western part of the ocean

- Temperate latitudes are characterized by winds that are relatively unstable in direction, and a fairly frequent recurrence of storm winds with a speed of more than 16 m / s, and their maximum speed at times reaches 45 m / s

- In tropical latitudes - trade winds

In the tropics, typhoons often form (from the Chinese “tai feng” - a big wind) - a tropical cyclone, inside which hurricane-force winds blow at speeds up to 100 km / h.

Organic World of the Pacific

The organic world of the Pacific Ocean is rich and varied. It is the richest in the number of species of living organisms. In general, the ocean inhabits about 100 thousand species of animals. Only plant plankton has about 1300 species. It accounts for half of the total mass of living organisms in the oceans.

Brown algae are abundant in the cold and temperate waters of the Pacific Ocean. In the Southern Hemisphere, in these latitudes, a giant from the world of algae grows 200 m long.

Coral reefs are one of the marvels of the tropical seas. Coral structures of various colors and shapes create a magical world underwater. Among the lilac, green, orange, yellow branches of coral buildings, bright silhouettes of fish flicker; shellfish, starfish and algae live here.

Coral reefs are created by living organisms - coral polyps living in colonies. A branched coral colony has been growing for many years, the growth rate is 10-20 cm per year.

For the development of corals, sea water with a salinity of 27-40‰ and a temperature of at least +20 ºС is required. Corals live only in the upper 50-meter layer of clean clear water.

In the southern tropical zone off the coast of Australia, a unique natural complex of the Great Barrier Reef has formed. This is the largest "mountain range" on Earth created by organisms.

It is comparable in size to the Ural Range.

The Pacific Ocean in people's lives

About half of the world's population lives along the shores of the Pacific Ocean. The life of many of them is inextricably linked with the ocean and depends on it.

The longest sea routes run through this ocean, connecting the port cities of different continents. However, the economic activity of people has led to a serious problem of pollution of the Great Ocean. Entire islands of debris have accumulated in its waters.

The message about the Pacific can be used by students in grades 5-7. If you are a student of grades 2-3, it is better to shorten the report by selecting the main facts.

Mankind has always been attracted by secrets hidden from its sight. From the vast expanses of the Universe to the deepest points of the World Ocean... Modern technologies partially make it possible to learn some secrets of the Earth, Water and Space. The more the veil of secrecy opens, the more a person wants to know, because new knowledge gives rise to questions. The largest, oldest and least explored Pacific Ocean is no exception. Its influence on the processes that take place on the planet is obvious: it is it that makes it possible for a deeper and more thorough study. The average depth, the direction of currents, communication with the seas and other water bodies - everything matters for the optimal use of man's unlimited resources.

World Ocean

All biological species on Earth depend on water, it is the basis of life, so the importance of studying the hydrosphere in all its manifestations becomes a priority for humanity. In the process of forming this knowledge, much attention is paid to both fresh sources and huge volumes of salt resources. The world ocean is the main part of the hydrosphere, which occupies 94% of the earth's surface. and archipelagos share water spaces, which makes it possible to territorially designate them on the face of the planet. On the modern map of the world since 1953, the international hydrogeographic society has marked four Indian, Arctic and Pacific. Each of them has the corresponding coordinates and boundaries, which are rather arbitrary for the movement of water flows. Relatively recently, the fifth ocean was singled out - the Southern Ocean. All of them differ significantly in area, water volumes, depths and composition. More than 96% of the entire hydrosphere is salty ocean water, which moves in vertical and horizontal directions and has its own global mechanism for metabolism, creation and use of energy flows. In the life of a modern person, the World Ocean plays a significant role: it forms the climatic conditions on the continents, provides an indispensable transport structure, gives people a lot of resources, including biological ones, and at the same time remains an ecosystem, the possibilities of which have not yet been fully explored.

Pacific Ocean

49.5% of the area of ​​the World Ocean and 53% of the volume of its water resources is occupied by its most ancient and mysterious part. The Pacific Ocean with incoming seas has the greatest extent of its water area: from north to south - 16 thousand km, from west to east - 19 thousand km. Most of it is located in the southern latitudes. The most significant are the numerical expressions of quantitative characteristics: volume - 710 million km 3, occupied area - almost 180 million km 3. The average depth of the Pacific Ocean, according to various estimates, varies from 3900 to 4200 meters. The only continent that is not washed by its waters is Africa. More than 50 states are located on its coast and islands, with all parts of the hydrosphere it has conditional boundaries and a constant exchange of flows. The number of islands located in the Pacific Ocean exceeds 10 thousand, they have different sizes and structure of formation. More than 30 seas are included in its water area (including internal ones), their area occupies 18% of the entire surface, the largest part is located on the western coast and washes Eurasia. The greatest depth of the Pacific Ocean, like the entire World Ocean, is in the Mariana Trench. Its research has been going on for more than 100 years, and the more information about the deep-sea quarry becomes available, the more it is of interest to scientists around the world. The shallowest depth of the Pacific Ocean is observed in its coastal zones. They have been studied quite well, but, given their constant use in human economic activity, the need for further scientific research is increasing.

History of development

The peoples who inhabited the Pacific coast on different continents knew a lot about its individual parts, but did not represent the full power and size of this body of water. The first European who saw a small coastal bay was the Spaniard - the conquistador Vasco de Balboa, who for this overcame the high mountain ranges of the Isthmus of Panama. He took what he saw for the sea and called it the South. That is why the discovery of the Pacific Ocean and giving it its present name is the merit of Magellan, who was very lucky with the conditions in which he crossed its southern part. This name does not at all correspond to the true nature of this aquatic giant, but it has taken root more than all the others that have been proposed as it has been studied. Many expeditions followed in the footsteps of Magellan, the Pacific Ocean attracted new researchers with a large number of questions. The Dutch, the British, the Spaniards were looking for ways to communicate with known lands and in parallel opened new ones. Everything was of interest to researchers: what is the greatest depth of the Pacific Ocean, the speed and direction of movement of water masses, salinity, flora and fauna of waters, etc. Scientists managed to collect more accurate information in the 19th-20th centuries, this is the period of formation of oceanology as a science. But the first attempt to determine the depth of the Pacific Ocean was made by Magellan using a hemp line. He failed - the bottom could not be reached. A lot of time has passed since then, and today the results of ocean depth measurements can be seen on any map. Modern scientists use improved technology and can, with a high degree of probability, indicate where the depth of the Pacific Ocean is maximum, where places with a lower level lie, and where shoals lie.

Bottom relief

More than 58% of the earth's surface is occupied by the ocean floor. It has a varied relief - these are large plains, high ridges and deep depressions. In percentage terms, the ocean floor can be divided as follows:

1. Continental shallow (depth from 0 to 200 meters) - 8%.
2. Continental slopes (from 200 to 2500 meters) - 12%.
3. Ocean bed (from 2500 to 6000 meters) - 77%.
4. Maximum depths (from 6000 to 11000 meters) - 3%.

The ratio is quite approximate, 2/3 of the ocean floor was measured, and the data of various research expeditions may vary due to constant movement. The accuracy of measuring instruments increases every year, the information obtained earlier is corrected. In any case, the greatest depth of the Pacific Ocean, its minimum value and the average value depend on the topography of the ocean floor. The smallest depths, as a rule, are observed in the territory adjacent to the continents - this is the coastal part of the oceans. It can have a length of 0 to 500 meters, the average varies within 68 meters.

The continental shelf is characterized by a slight slope, that is, it is flat, with the exception of the coasts, on which the mountain ranges are located. In this case, the relief is quite diverse, depressions and bottom cracks can reach a depth of 400-500 meters. The minimum depth of the Pacific Ocean is less than 100 meters. The large reef and its lagoons with warm clear water provide a unique opportunity to see everything that happens on the bottom. Continental slopes also vary in slope and length, depending on the location of the coastal region. Their typical structure has a smooth, gradually lowering relief or the presence of a deep canyon. They tried to explain this fact in two versions: tectonic and flooding of river valleys. In favor of the latter assumption, soil samples from their bottom, which also contains silt, speak. These canyons are quite deep, due to their average depth of the Pacific Ocean is quite impressive. The bed is a flatter part of the relief with constant depth. Cracks, crevices and depressions at the bottom of the World Ocean are a frequent phenomenon, and the maximum value of their depths, as already mentioned, is observed in the Mariana Trench. The relief of the bottom of each area is individual, it is fashionable to compare it with land landscapes.

Features of the relief of the Pacific Ocean

The depth of the abysses in the Northern Hemisphere and a significant part of the Southern Hemisphere (and this is more than 50% of the entire area of ​​the ocean floor) varies within 5000 meters. In the northwestern part of the ocean, there are a large number of depressions and cracks that are located along the edge of the coastal zone, in the region of the continental slope. Almost all of them coincide with mountain ranges on land and have an oblong shape. This is typical for the coast of Chile, Mexico and Peru, and this group also includes the Aleutian northern basin, the Kuril and Kamchatka. In the Southern Hemisphere, a depression 300 meters long is located along the islands of Tonga, Kermadec. To find out how deep the Pacific Ocean is on average, people used various measuring instruments, the history of which is closely connected with research work in the water spaces of the planet.

Depth gauges

Lot is the most primitive means of depth measurement. It's a rope with a load on the end. This tool is not suitable for measuring sea and ocean depths, since the weight of the lowered cable will exceed the weight of the load. The results of the measurement with the help of the lot gave a distorted picture or did not bring any results at all. An interesting fact: Brook's lot was actually invented by Peter 1. His idea was that a load was attached to the cable, which popped up when it hit the bottom. This stopped the process of lowering the lot and made it possible to determine the depth. A more advanced depth gauge worked on the same principle. Its feature was the possibility of capturing part of the soil for further research. All these measuring devices have a significant drawback - the measurement time. To fix the value of a large depth, the cable must be lowered in stages over several hours, while the research vessel must stand in one place. Over the past 25 years, soundings have been carried out with the help of an echo sounder, which works on the principle of signal reflection. The operating time has been reduced to a few seconds, while on the echogram you can view the types of bottom soils and detect sunken objects. To determine what the average depth of the Pacific Ocean is, it is necessary to take a large number of measurements, which are then summed up, as a result, the delta is calculated.

History of soundings

The 19th century is "golden" for oceanography in general and the Pacific Ocean in particular. The first expeditions of Kruzenshtern and Lisyansky set as their goal not only the measurement of depths, but also the determination of temperatures, pressure, density and salinity of water. 1823-1826: taking part in the research work of O. E. Kotzebue, the physicist E. Lenz used the bathometer he created. The year 1820 was marked by the discovery of Antarctica, the expedition of navigators F. F. Bellingshausen and M. P. Lazarev studied the northern seas of the Pacific Ocean. At the end of the 20th century (1972-1976), the British vessel Challenger carried out a comprehensive oceanographic survey, which provided most of the information used to this day. Since 1873, the United States, with the help of the navy, measured the depths and fixed the topography of the Pacific Ocean floor for laying a telephone cable. The 20th century was marked by a technological breakthrough for all mankind, which to a large extent affected the work of Pacific Ocean researchers, who asked a lot of questions. Swedish, British and Danish expeditions set off on a round-the-world trip to explore the largest body of water on our planet. How deep is the Pacific Ocean at its maximum and minimum? Where are these points located? What underwater or surface currents influence them? What caused them to form? The study of the bottom was carried out for a long time. From 1949 to 1957, the crew of the Vityaz research ship mapped many relief elements on a map of the Pacific Ocean floor and tracked its currents. The watch was continued by other vessels that constantly cruised in the water area to obtain the most accurate and timely information. In 1957, the scientists of the Vityaz vessel determined the point at which the greatest depth of the Pacific Ocean is observed - the Mariana Trench. Until today, its bowels are carefully studied not only by oceanologists, but also by biologists, for whom there was also a lot of interesting things.

Mariana Trench

The trench stretched for 1500 meters along the islands of the same name in the western part of the Pacific coast. It looks like a wedge and has varying depths throughout. The history of occurrence is connected with the tectonic activity of this part of the Pacific Ocean. In this segment, it gradually goes under the Philippine one, moving 2-3 cm per year. At this point, the depth of the Pacific Ocean is maximum, and the depth of the World Ocean too. Measurements have been taken for hundreds of years, and each time their values ​​are corrected. The 2011 study gives the most surprising result, which may not be conclusive. The deepest point of the Mariana Trench is the "Challenger Abyss": the bottom is at a distance of 10,994 m below sea level. For its study, a bathyscaphe equipped with cameras and devices for soil sampling was used.

How deep is the Pacific Ocean?

There is no unequivocal answer to this question: the bottom topography is so complex and not fully understood that each figure mentioned can be corrected in the near future. The average depth of the Pacific Ocean is 4000 meters, the smallest is less than 100 meters, the famous "Challenger Abyss" is characterized by impressive figures - almost 11,000 meters! Along the mainland there are a number of depressions, which also amaze with their depths, for example: the Vityaz 3 depression (Tonga trench, 10,882 meters); "Argo" (9165, Northern New Hebrides Trench); Cape Johnson (Philippine Trench, 10,497), etc. The Pacific Ocean contains the largest number of the deepest points of the World Ocean. Modern oceanologists expect a lot of interesting work and amazing discoveries.

Flora and fauna

Notable for researchers is the fact that even at a maximum depth of 11,000 meters, biological activity was found: tiny microorganisms survive without light, while being subjected to the monstrous pressure of many tons of water. The vastness of the Pacific Ocean itself is an ideal habitat for many species of animals and plants. Which is confirmed by facts and concrete figures. More than 50% of the biomass of the World Ocean lives in the Pacific, the diversity of species is explained by the fact that vast expanses of water are located in all belts of the planet. Tropical and subtropical latitudes are more densely populated, but the northern borders are not empty either. A characteristic feature of the fauna of the Pacific Ocean is endemism. Here are the habitats of the most ancient animals of the planet, endangered species (sea lions, sea otters). Coral reefs are one of the wonders of nature, and the richness of flora and fauna attracts not only a lot of tourists, but also explorers. The Pacific Ocean is the largest and most powerful. The task of people is to study and understand all the processes taking place in it, which will help reduce the degree of harm caused by humans to this unique ecosystem.