Geographical position of the Pacific Ocean between which continents. Geographical position of the Pacific Ocean: description and features
Geographical position
Describe the Pacific GP as planned: .
1. The area of the ocean and its place among other oceans.
2.The location of the ocean relative to the equator, the tropics (arctic circles), the prime and 180th meridians.
3. Extreme points of the ocean, coordinates. Length in degrees and kilometers from north to south and from west to east.
4.Which continents are washed by the ocean.
5.Location in hemispheres and climate zones.
6.Oceans, seas that are part of the ocean
7. Location relative to continents and other oceans.
8. Ocean currents.
SIZE Area with seas 178.620 million km², volume 710 million km³, average depth 3980 m, maximum 11022 m. The Pacific Ocean occupies half of the Earth's total water surface, and more than thirty percent of the planet's surface area.
Name Its original name was "Great", and it was given by the Spaniard Vasco Nunez de Balboa, who, exploring the New World, September 30th 1513 g. crossed the Isthmus of Panama from north to south. Magellan discovered the Pacific Ocean in the fall of 1520 and named the ocean the Pacific Ocean, “because,” as one of the participants reports, during the passage from Tierra del Fuego to the Philippine Islands, more than three months, “we never experienced the slightest storm.”
In 1534, on the instructions of the Spanish king Carlos V, the discoverer of the Pacific Ocean, the Castilian hidalgo Don Vasco Nunez de Balboa, carried out the first topographical studies for the construction of a canal through the Panama
Map - path Vasco Nunez Balboa, Central America, 1513.
Composition of the Sea: Beringovo , Okhotsk , Japanese , East China , Yellow , South China , Javanese , Sulawesi , Sulu , Filipino , Coral , Fiji , Tasmanovo etc. Seas Amundsen , Bellingshausen , Rossa are now included in South ocean. In terms of the number (about 10 thousand) and total area of islands (about 3.6 million km²), the Pacific Ocean ranks among oceans first place. In the northern part - Aleutian; in the western - Kuril , Sakhalin , Japanese , Filipino , Large And Lesser Sunda , New Guinea , New Zealand , Tasmania; in the central and southern regions there are numerous small islands. Mark the islands and seas of the Pacific Ocean on the map.
Bottom relief
The bottom topography is varied. In the east - East Pacific Rise, in the central part there are many basins (North-Eastern, North-Western, Central, Eastern, Southern, etc.), deep-sea trenches: in the north - Aleutian, Kuril-Kamchatka, Izu-Boninsky;
in the West - Mariana(with maximum depth
World Ocean - 11,022 m), Philippine, etc.;
in the east - Central American, Peruvian
and others. 
Currents
The main surface currents: in the northern part of the Pacific Ocean - warm Kuroshio, North Pacific and Alaskan and cold Californian and Kuril; in the southern part - the warm South Trade Wind and East Australian Wind and the cold Western Wind and Peruvian Wind. Surface water temperature equator from 26 to 29 °C, in the polar regions up to −0.5 °C. Salinity 30-36.5 ‰.
Label the currents of the Pacific Ocean on an outline map. 
Flora and fauna of the Pacific Ocean
Economic significance
The Pacific Ocean accounts for about half of the world's fish catch ( pollock , herring , salmon , cod , sea bass and etc.). Production crabs , shrimp , oysters .
Important sea and air communications between the countries of the Pacific basin and transit routes between countries lie across the Pacific Ocean Atlantic And Indian oceans. Large ports : Vladivostok , Nakhodka (Russia), Shanghai (China), Singapore(Singapore), Sydney (Australia), Vancouver (
A. strong dismemberment in the west and east
b. strong dismemberment in the west and weak in the east
V. weak dismemberment in the west and strong in the east
G. weak dismemberment in the west and east
The widest part of the Pacific Ocean is located at... latitudes
A. equatorial and tropical
b. tropical and temperate
V. temperate and arctic
Arctic and Antarctic
The most specific type of water movement in the Pacific Ocean is...
A. ocean currents
b. wind waves
V. tsunami
ebbs and flows
An analogue of the Gulf Stream (Atlantic Ocean) in the Pacific Ocean is the current...
A. Western winds
b. Kuroshio
V. North Pacific
Californian
Ice in the Pacific Ocean is found mainly in its... parts A. northern and central b. central and southern
V. southern and northern
The most diverse organic world in the Pacific Ocean is characterized by waters...
A. equatorial and tropical latitudes
b. tropical and temperate latitudes c. temperate and arctic latitudes arctic and antarctic latitudes
The first European to see the waters of the Pacific Ocean...
A. Magellan
b. Balboa
V. Drake Tasman
Introduction
Pacific Ocean- the largest and most ancient of all oceans. Its area is 178.6 million km2. It can easily accommodate all the continents and islands combined, which is why it is sometimes called the Great. The name “Pacific” is associated with the name of F. Magellan, who traveled around the world and sailed through the Pacific Ocean under favorable weather conditions.
This ocean is truly great: it occupies 1/3 of the surface of the entire planet and almost 1/2 of the area of the World Ocean. The ocean has an oval shape, it is especially wide at the equator.
The peoples inhabiting the Pacific coasts and islands have been sailing the ocean for a long time and exploring its riches. Information about the ocean was accumulated as a result of the voyages of F. Magellan and J. Cook. Its wide study began in the 19th century with the first round-the-world Russian expedition of I.F. Kruzenshtern. Currently, a special international organization has been created for the study of the Pacific Ocean. In recent years, new data have been obtained about its nature, its depth has been determined, currents and bottom topography have been studied, biological resources of the ocean.
Geographical position
Great or Pacific Ocean - the greatest ocean on Earth. It accounts for about half (49%) of the area and more than half (53%) of the volume of the waters of the World Ocean, and its surface area is equal to almost a third of the entire surface of the Earth as a whole. In terms of the number (about 10 thousand) and total area (more than 3.5 million km 2) of islands, it ranks first among the other oceans of the Earth.
In the northwest and west, the Pacific Ocean is limited by the shores of Eurasia and Australia, in the northeast and east by the shores of North and South America. The border with the Arctic Ocean is drawn through the Bering Strait along the Arctic Circle. The southern border of the Pacific Ocean (as well as the Atlantic and Indian) is considered to be the northern coast of Antarctica. When distinguishing the Southern (Antarctic) Ocean, its northern boundary is drawn along the waters of the World Ocean, depending on the change in the regime of surface waters from temperate latitudes to Antarctic latitudes. It runs approximately between 48 and 60° S.
Ocean Boundaries
The boundaries with other oceans south of Australia and South America are also drawn conditionally along the water surface: with the Indian Ocean - from Cape South East Point at approximately 147° E, with the Atlantic Ocean - from Cape Horn to the Antarctic Peninsula. In addition to wide connections with other oceans in the south, there is communication between the Pacific and northern Indian Oceans through the interisland seas and the straits of the Sunda archipelago.
The area of the Pacific Ocean from the Bering Strait to the shores of Antarctica is 178 million km 2, the volume of water is 710 million km 3.
The northern and western (Eurasian) shores of the Pacific Ocean are dissected by seas (more than 20 of them), bays and straits, separating large peninsulas, islands and entire archipelagos of continental and volcanic origin. The coasts of Eastern Australia, southern North America, and especially South America are generally straightforward and inaccessible from the ocean. With a huge surface area and linear dimensions (more than 19 thousand km from west to east and about 16 thousand km from north to south), the Pacific Ocean is characterized by weak development of the continental margins (only 10% of the bottom area) and a relatively small number of shelf seas.
Within the intertropical space, the Pacific Ocean is characterized by clusters of volcanic and coral islands.
Relief of the ocean floor
There are still different points of view on the question of the time of formation of the Pacific Ocean in its modern form, but, obviously, by the end of the Paleozoic era, a vast body of water already existed in the place of its basin, as well as the ancient continent of Pangea, located approximately symmetrically with respect to the equator . At the same time, the formation of the future Tethys Ocean began in the form of a huge bay, the development of which and the invasion of Pangea subsequently led to its disintegration and the formation of modern continents and oceans.
The bed of the modern Pacific Ocean is formed by a system of lithospheric plates, bounded on the ocean side by mid-ocean ridges, which are part of the global system of mid-ocean ridges of the World Ocean. These are the East Pacific Rise and the South Pacific Ridge, which, reaching a width of up to 2 thousand km in places, connect with each other in the southern part of the ocean and continue westward into the Indian Ocean. The East Pacific Ridge, extending northeast to the coast of North America, in the Gulf of California region, connects with the system of continental rift faults of the California Valley, the Yosemite Trench and the San Andreas Fault. The middle ridges of the Pacific Ocean themselves, unlike the ridges of other oceans, do not have a clearly defined axial rift zone, but are characterized by intense seismicity and volcanism with a predominance of emissions of ultrabasic rocks, i.e., they have the features of a zone of intensive renewal of the oceanic lithosphere. Throughout the entire length, the middle ridges and adjacent plate sections are intersected by deep transverse faults, which are also characterized by the development of modern and, especially, ancient intraplate volcanism. Located between the median ridges and limited by deep-sea trenches and transition zones, the vast floor of the Pacific Ocean has a complexly dissected surface, consisting of a large number of basins with a depth of 5000 to 7000 m or more, the bottom of which is composed of oceanic crust covered with deep-sea clays, limestones and silts of organic origin. . The bottom topography of the basins is mostly hilly. The deepest basins (about 7000 m or more): Central, Western Mariana, Philippine, Southern, Northeastern, East Carolinian.
Basins, archipelagos and islands
The basins are separated from each other or crossed by arched rises or blocky ridges on which volcanic structures are planted, within the intertropical space often crowned with coral structures. Their tops protrude above the water in the form of small islands, often grouped into linearly elongated archipelagos. Some of them are still active volcanoes, spewing streams of basaltic lava. But for the most part these are already extinct volcanoes, built on with coral reefs. Some of these volcanic mountains are located at a depth of 200 to 2000 m. Their peaks are leveled by abrasion; the position deep under water is obviously associated with the lowering of the bottom. Formations of this type are called guyots.
Of particular interest among the archipelagos of the central Pacific Ocean are the Hawaiian Islands. They form a chain 2,500 km long, stretching north and south of the Tropic of the North, and are the tops of huge volcanic massifs rising from the ocean floor along a powerful deep fault. Their visible height is from 1000 to 4200 m, and their underwater height is approximately 5000 m. In terms of their origin, internal structure and appearance, the Hawaiian Islands are a typical example of oceanic intraplate volcanism.
The Hawaiian Islands are the northern edge of a huge island group in the central Pacific Ocean, collectively known as Polynesia. The continuation of this group to approximately 10° S. are the islands of Central and Southern Polynesia (Samoa, Cook, Society, Tabuai, Marquesas, etc.). These archipelagos, as a rule, extend from northwest to southeast, along transform fault lines. Most of them are of volcanic origin and are composed of strata of basaltic lava. Some are topped by wide and gently sloping volcanic cones 1000-2000 m high. The smallest islands in most cases are coral structures. Similar features have numerous clusters of small islands located mainly north of the equator, in the western part of the Pacific lithospheric plate: the Mariana, Caroline, Marshall and Palau Islands, as well as the Gilbert Archipelago, which partially extends into the southern hemisphere. These groups of small islands are collectively called Micronesia. All of them are of coral or volcanic origin, mountainous and rise hundreds of meters above sea level. The coasts are surrounded by surface and underwater coral reefs, making navigation very difficult. Many small islands are atolls. Near some islands there are deep-sea ocean trenches, and to the west of the Mariana Archipelago there is a deep-sea trench of the same name, belonging to the transition zone between the ocean and the Eurasian continent.
In the part of the Pacific Ocean bed adjacent to the American continents, small single volcanic islands are usually scattered: Juan Fernandez, Cocos, Easter, etc. The largest and most interesting group are the Galapagos Islands, located near the equator near the coast of South America. This is an archipelago of 16 large and many small volcanic islands with the peaks of extinct and active volcanoes up to 1700 m high.
Transition zones from the ocean to the continents differ in the structure of the ocean floor and the characteristics of tectonic processes both in the geological past and at the present time. They surround the Pacific Ocean in the west, north and east. In different parts of the ocean, the processes of formation of these zones proceed differently and lead to different results, but everywhere they are distinguished by great activity both in the geological past and at the present time.
On the side of the ocean floor, transition zones are limited by arcs of deep-sea trenches, in the direction of which lithospheric plates move and the oceanic lithosphere subsides under the continents. Within the transition zones, the structure of the ocean floor and marginal seas is dominated by transitional types of the earth's crust, and oceanic types of volcanism are replaced by mixed effusive-explosive volcanism of subduction zones. Here we are talking about the so-called “Pacific Ring of Fire,” which encircles the Pacific Ocean and is characterized by high seismicity, numerous manifestations of paleovolcanism and volcanogenic landforms, as well as the existence within its boundaries of more than 75% of the planet’s currently active volcanoes. This is mainly mixed effusive-explosive volcanism of intermediate composition.
The southern region of the Pacific Ocean transition zone northeast of Australia is particularly complex. It extends from Kalimantan to New Guinea and further south to 20° S, bordering the Sokhul-Queensland shelf of Australia to the north. This entire section of the transition zone is a complex combination of deep-sea trenches with depths of 6000 m or more, submarine ridges and island arcs, separated by basins or areas of shallow water.
Off the eastern coast of Australia, between New Guinea and New Caledonia, is the Coral Sea. From the east it is limited by a system of deep-sea trenches and island arcs (New Hebrides, etc.). The depths of the Coral basin and other seas of this transitional region (the Fiji sea and especially the Tasman sea) reach 5000-9000 m, their bottom is composed of oceanic or transitional type crust.
The hydrological regime of the northern part of this area favors the development of corals, which are especially common in the Coral Sea. On the Australian side, it is limited by a unique natural structure - the Great Barrier Reef, which stretches along the continental shelf for 2,300 km and reaches a width of 150 km in the southern part. It consists of individual islands and entire archipelagos, made of coral limestone and surrounded by underwater reefs of living and dead coral polyps. Narrow channels crossing the Great Barrier Reef lead to the so-called Great Lagoon, the depth of which does not exceed 50 m.
The transition zone of the eastern part of the Pacific Ocean, facing the continents of North and South America, differs significantly from its western margin. There are no marginal seas or island arcs. A strip of narrow shelf with mainland islands stretches from the south of Alaska to Central America. Along the western coast of Central America, as well as from the equator along the edge of South America, there is a system of deep-sea trenches - Central American, Peruvian and Chilean (Atacama) with maximum depths of more than 6000 and 8000 m, respectively. Obviously, the process of formation of this part of the ocean and neighboring continents proceeded in interaction deep-sea trenches and continental lithospheric plates that existed at that time. North America moved onto the trenches along its path to the west and closed them, and the South American Plate moved the Atacama Trench to the west. In both cases, as a result of the interaction of oceanic and continental structures, folding occurred, the marginal parts of both continents were uplifted, and powerful suture zones were formed—the North American Cordillera and the Andes of South America. Each of these structural zones is characterized by intense seismicity and the manifestation of mixed types of volcanism. O.K. Leontiev considered it possible to compare them with the underwater ridges of the island arcs of the western transition zone of the Pacific Ocean.
Climate and hydrological conditions
The Pacific Ocean extends between 60° north and south latitude. In the north, it is almost closed by the landmass of Eurasia and North America, separated from each other only by the shallow Bering Strait with its smallest width of 86 km, connecting the Bering Sea of the Pacific Ocean with the Chukchi Sea, which is part of the Arctic Ocean.
Eurasia and North America extend south all the way to the Tropic of the North in the form of vast, massive land areas that represent centers of formation of continental air that can influence the climate and hydrological conditions of neighboring parts of the ocean. To the south of the Northern Tropic, the land becomes fragmented; up to the coast of Antarctica, its large land areas are only Australia in the southwest of the ocean and South America in the east, especially its extended part between the equator and 20° S latitude. South of 40° S. The Pacific Ocean, together with the Indian and Atlantic Oceans, merge into a single water surface, uninterrupted by large areas of land, over which oceanic air of temperate latitudes is formed, and into which Antarctic air masses freely penetrate.
The Pacific Ocean reaches its greatest width (almost 20 thousand km) within the tropical-equatorial space, i.e. in that part where the thermal energy of the sun is most intensively and regularly received throughout the year. Because of this, the Pacific Ocean receives more solar heat throughout the year than other parts of the world's oceans. And since the distribution of heat in the atmosphere and on the water surface depends not only on the direct distribution of solar radiation, but also on the air exchange between land and water surface and water exchange between different parts of the World Ocean, it is quite clear that the thermal equator over the Pacific Ocean is shifted to the northern hemisphere and runs approximately between 5 and 10°N latitude, and the northern part of the Pacific Ocean is generally warmer than the southern one.
Pressure systems
Let us consider the main pressure systems that determine meteorological conditions (wind activity, precipitation, air temperature), as well as the hydrological regime of surface waters (current systems, temperature of surface and subsurface waters, salinity) of the Pacific Ocean throughout the year. First of all, this is a subequatorial depression (calm zone), somewhat expanded towards the northern hemisphere. This is especially pronounced in the summer of the northern hemisphere, when a vast and deep pressure depression is established over highly heated Eurasia, centered in the Indus River basin. Streams of moisture-unstable air from subtropical high pressure centers of both the northern and southern hemispheres rush towards this depression. Most of the northern half of the Pacific Ocean at this time is occupied by the North Pacific High, along the southern and eastern periphery of which the monsoons blow towards Eurasia. They are associated with heavy rainfall, the amount of which increases towards the south. The second monsoon flow moves from the southern hemisphere, from the side of the subtropical high pressure belt. In the northwest there is a weakened westerly transport towards North America.
In the southern hemisphere, where it is winter at this time, strong westerly winds carrying air from temperate latitudes cover the waters of all three oceans south of the parallel of 40° S. almost to the shores of Antarctica, where they are replaced by easterly and southeasterly winds blowing from the mainland. The westerly transport operates at these latitudes of the southern hemisphere in the summer, but with less force. Winter conditions in these latitudes are characterized by heavy precipitation, stormy winds, and high waves. With a large number of icebergs and floating sea ice, travel in this part of the world's oceans poses great dangers. It is not for nothing that sailors have long called these latitudes “the roaring forties.”
At the corresponding latitudes in the northern hemisphere, the dominant atmospheric process is also westerly transport, but due to the fact that this part of the Pacific Ocean is closed by land from the north, west and east, in winter the meteorological situation there is slightly different than in the southern hemisphere. With the westerly transport, cold and dry continental air from Eurasia enters the ocean. It is involved in the closed system of the Aleutian Low, which forms over the northern part of the Pacific Ocean, is transformed and is carried by south-westerly winds to the shores of North America, leaving heavy precipitation in the coastal zone and on the slopes of the Cordillera of Alaska and Canada.
Wind systems, water exchange, topography features of the ocean floor, the position of continents and the outlines of their coasts influence the formation of surface ocean currents, and these, in turn, determine many features of the hydrological regime. In the Pacific Ocean, with its vast size within the intertropical space, there is a powerful system of currents generated by the trade winds of the northern and southern hemispheres. In accordance with the direction of movement of the trade winds along the equatorward outskirts of the North Pacific and South Pacific maximums, these currents move from east to west, reaching a width of more than 2000 km. The Northern Trade Wind Current heads from the coast of Central America to the Philippine Islands, where it splits into two branches. The southern one partially spreads over the interisland seas and partially feeds the surface inter-trade wind countercurrent running along the equator and to the north of it, moving towards the Central American isthmus. The northern, more powerful branch of the North Trade Wind Current heads towards the island of Taiwan, and then enters the East China Sea, skirting the Japanese islands from the east, giving rise to a powerful system of warm currents in the northern part of the Pacific Ocean: this is the Kuroshio, or Japan Current, moving at a speed of 25 to 80 cm/s. Near the island of Kyushu, the Kuroshio branches, and one of the branches enters the Sea of Japan under the name of the Tsushima Current, the other goes out into the ocean and follows along the eastern coast of Japan, until at 40 ° N. latitude. it is not pushed to the east by the cold Kuril-Kamchatka countercurrent, or Oyashio. The continuation of the Kuroshio to the east is called the Kuroshio Drift, and then the North Pacific Current, which heads towards the shores of North America at a speed of 25-50 cm/s. In the eastern part of the Pacific Ocean, north of the 40th parallel, the North Pacific Current branches into the warm Alaska Current, heading towards the shores of Southern Alaska, and the cold California Current. The latter, following along the coast of the mainland, south of the tropic flows into the Northern Trade Wind Current, closing the northern gyre of the Pacific Ocean.
Most of the Pacific Ocean north of the equator experiences high surface water temperatures. This is facilitated by the large width of the ocean in the intertropical space, as well as by the system of currents that carry the warm waters of the Northern Trade Wind Current north along the coast of Eurasia and its neighboring islands.
The Northern Trade Wind Current carries water with temperatures of 25...29 °C all year round. High surface water temperatures (up to a depth of approximately 700 m) persist within Kuroshio to almost 40° N latitude. (27...28 °C in August and up to 20 °C in February), as well as within the North Pacific Current (18...23 °C in August and 7... 16 °C in February). A significant cooling effect on the northeast of Eurasia up to the north of the Japanese Islands is exerted by the cold Kamchatka-Kuril Current originating in the Bering Sea, which in winter is intensified by cold waters coming from the Sea of Okhotsk. From year to year, its power fluctuates greatly depending on the severity of winters in the Bering and Okhotsk Seas. The area of the Kuril Islands and Hokkaido is one of the few in the North Pacific Ocean where there is ice in winter. At 40° N latitude when meeting the Kuroshio Current, the Kuril Current plunges to depth and flows into the North Pacific. In general, the temperature of the waters of the northern part of the Pacific Ocean is higher than in the southern part at the same latitudes (5...8 °C in August in the Bering Strait). This is partly due to limited water exchange with the Arctic Ocean due to the threshold in the Bering Strait.
The Southern Trade Wind Current moves along the equator from the coast of South America to the west and even enters the northern hemisphere to approximately 5° N latitude. In the area of the Moluccas Islands, it branches: the bulk of the water, together with the Northern Trade Wind Current, enters the Inter-Trade Wind Countercurrent system, and the other branch penetrates the Coral Sea and, moving along the coast of Australia, forms the warm East Australian Current, which flows into the current off the coast of the island of Tasmania Western winds. The surface water temperature in the South Trade Wind Current is 22...28 °C, in the East Australian Current in winter it varies from north to south from 20 to 11 °C, in summer – from 26 to 15 °C.
The Pacific Ocean, to a greater extent than other parts of the World Ocean, is the arena for the emergence of the atmospheric process known as tropical cyclones or hurricanes. These are vortices of small diameter (no more than 300-400 km) and high speed (30-50 km/h). They form within the tropical trade wind convergence zone, usually during the summer and autumn of the northern hemisphere, and move first in accordance with the direction of the prevailing winds, from west to east, and then along the continents to the north and south. For the formation and development of hurricanes, a vast expanse of water is required, heated from the surface to at least 26 ° C, and atmospheric energy, which would impart forward motion to the resulting atmospheric cyclone. The characteristics of the Pacific Ocean (its size, in particular, its width within the intertropical space, and the maximum surface water temperatures for the World Ocean) create conditions over its waters that are conducive to the formation and development of tropical cyclones.
The passage of tropical cyclones is accompanied by catastrophic phenomena: winds of destructive force, strong waves in the open sea, heavy rainfall, flooding of plains on adjacent land, floods and destruction, leading to severe disasters and loss of life. Moving along the coasts of continents, the most powerful hurricanes go beyond the intratropical space, transforming into extratropical cyclones, sometimes reaching great strength.
The main area of origin of tropical cyclones in the Pacific Ocean is located south of the Tropic of the North, east of the Philippine Islands. Moving initially to the west and northwest, they reach the coast of Southeast China (in Asian countries these vortices have the Chinese name “typhoon”) and move along the continent, deviating towards the Japanese and Kuril Islands.
The branches of these hurricanes, deviating to the west south of the tropic, penetrate into the interisland seas of the Sunda archipelago, into the northern part of the Indian Ocean and cause destruction in the lowlands of Indochina and Bengal. Hurricanes originating in the southern hemisphere north of the Tropic of the South move towards the coast of North-Western Australia. There they are called locally "BILLY-BILLY". Another center for the generation of tropical hurricanes in the Pacific Ocean is located off the western coast of Central America, between the Tropic of the North and the equator. From there, hurricanes rush to the offshore islands and shores of California.
In the first years of the new millennium, an increase in the frequency of tropical cyclones (typhoons) off the Asian and North American coasts of the Pacific Ocean, as well as an increase in their power, was noted. This applies not only to the Pacific, but also to other oceans of the Earth. This phenomenon may be one of the consequences of global warming. The increased warming of the surface waters of the oceans in tropical latitudes also increases the atmospheric energy that provides the forward movement, speed of movement and destructive power of hurricanes.
Animal and plant life
More than half of the living matter of the entire Earth's oceans is concentrated in the waters of the Pacific Ocean. This applies to both plants and animal populations. The organic world as a whole is distinguished by species richness, antiquity and a high degree of endemism.
The fauna, totaling up to 100 thousand species, is characterized by mammals that live mainly in temperate and high latitudes.A representative of toothed whales, the sperm whale, is widespread; among toothless whales, there are several species of striped whales. Their fishing is strictly limited. Separate genera of the family of eared seals (sea lions) and fur seals are found in the south and north of the ocean. Northern fur seals are valuable fur-bearing animals, the hunting of which is strictly controlled. The northern waters of the Pacific Ocean are also home to the now very rare Steller sea lion (an eared seal) and the walrus, which has a circumpolar range but is now on the verge of extinction.
The fish fauna is very rich. In tropical waters there are at least 2000 species, in the northwestern seas - about 800 species. The Pacific Ocean accounts for almost half of the world's fish catch. The main fishing areas are the northern and central parts of the ocean. The main commercial families are salmon, herring, cod, anchovies, etc.
The predominant mass of living organisms inhabiting the Pacific Ocean (as well as other parts of the World Ocean) are invertebrates that live at various levels of ocean waters and on the bottom of shallow waters: these are protozoa, coelenterates, arthropods (crabs, shrimp), mollusks (oysters, squids) , octopuses), echinoderms, etc. They serve as food for mammals, fish, seabirds, but also constitute an essential component of marine fisheries and are objects of aquaculture.
The Pacific Ocean, due to the high temperatures of its surface waters in tropical latitudes, is especially rich in various types of corals, including those with a calcareous skeleton. In no other ocean is there such an abundance and variety of coral structures of various types as in the Pacific.
The basis of plankton is made up of single-celled representatives of the animal and plant world. There are almost 380 species of phytoplankton in the Pacific Ocean.
The greatest wealth of the organic world is characteristic of areas where so-called upwelling is observed (the rise to the surface of deep waters rich in minerals) or mixing of waters with different temperatures occurs, which creates favorable conditions for the nutrition and development of phyto- and zooplankton, which feed on fish and other nekton animals. In the Pacific Ocean, upwelling areas are concentrated off the coast of Peru and in divergence zones in subtropical latitudes, where there are areas of intensive fishing and other industries.
Whale Sperm Whale Eared seal
Anchovy
Sea lion
"El Niño"
Against the background of normal, annually recurring conditions, the Pacific Ocean is characterized by a phenomenon that disrupts the usual rhythm of circulation and hydrological processes and is not observed in other parts of the World Ocean. It manifests itself at intervals of 3 to 7 years and entails a disruption of the usual environmental conditions within the intertropical space of the Pacific Ocean, affecting the life of living organisms, including the population of coastal regions of land. It consists of the following: at the end of November or December, i.e. shortly before Christmas (why the phenomenon received the popular name “El Niño”, which means "Holy Child"), for reasons that have not yet been clarified, the southern trade wind is weakening and, consequently, the Southern Trade Wind Current and the influx of relatively cold waters to the shores of South America and to the west of it are weakening. At the same time, winds that are usually unusual for these latitudes begin to blow from the northwest towards the southern hemisphere, carrying relatively warm waters to the southeast, strengthening the Intertrade Wind Countercurrent. This disrupts the upwelling phenomenon both in the intertropical divergence zone and off the coast of South America, which, in turn, leads to the death of plankton, and then the fish and other animals that feed on them.
The El Niño phenomenon has been regularly observed since the second half of the 19th century. It was found that in many cases it was accompanied by a violation of environmental conditions not only in the ocean, but also in vast areas of adjacent land: an abnormal increase in precipitation in the arid regions of South America and, conversely, droughts in the island and coastal regions of Southeast Asia and Australia. The consequences of El Niño 19 82-19 83 and 19 9 7-19 9 8 are considered especially severe, when this unfavorable phenomenon lasted for several months.
The Pacific Ocean is the largest of the oceans. Its area is 178.7 million km 2. The ocean is larger in area than all the continents taken together, and has a rounded configuration: noticeably elongated from northwest to southeast, so air and water masses reach their greatest development here in the vast northwestern and southeastern waters. 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 equatorial-tropical latitudes, so it is the warmest of the oceans. The volume of water is 710.4 million km 3 (53% of the volume of waters of the World Ocean). The average ocean depth is 3980 m, the maximum is 11,022 m (Mariana Trench).
The ocean washes the shores of almost all continents with its waters, except Africa. It reaches Antarctica with a wide front, and its cooling influence extends through the waters far to the north. On the contrary, Quiet is protected from cold air masses by its significant 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 half. The Pacific Ocean basin is connected to all other oceans. The boundaries between them are quite arbitrary. The most reasonable border is 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 Sterneck on the Antarctic Peninsula). The border with the Indian Ocean is arbitrary.
It is usually carried out as follows: the Malay archipelago is attributed to the Pacific Ocean, and between Australia and Antarctica the oceans are delimited along the meridian of Cape South (Tasmania Island, 147° E). The official boundary with the Southern Ocean ranges from 36° S. w. off the coast of South America to 48° S. w. (at 175° W). The outlines of the coastline are quite simple on the eastern edge of the ocean and very complex on the western edge, where the ocean occupies a complex of marginal and interisland seas, island arcs and deep-sea trenches. This is a vast area of the largest horizontal and vertical division of the earth's crust on Earth. The marginal type includes seas off the coasts of Eurasia and Australia. Most of the interisland seas are located in the Malay Archipelago region. They are often combined under the general name Australasian. 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 are unparalleled in the Pacific Ocean. The coasts of North and South America are slightly indented; there are no marginal seas or such large clusters of islands. Deep-sea trenches are located directly off the coasts of 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 part of the Pacific mobile belt (“ring of fire”), which is characterized by powerful manifestations of modern volcanism and seismicity.
The islands of the central and southwestern parts of the ocean are united under the general name Oceania.
The huge size of the Pacific Ocean is associated with its unique records: it is the deepest, the warmest on the surface, the highest wind waves, the most destructive tropical hurricanes and tsunamis are formed here, 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, residents of the Pacific coasts and islands have developed the biological resources of coastal waters and made short voyages. Over time, other resources began to be involved in the economy, and their use gained wide industrial scope. Nowadays, the Pacific Ocean plays a very important role in the lives 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 are connected to the Arctic Ocean through the Bering Strait.
The border between them runs along a conventional line: Cape Unikyn (Chukchi Peninsula) - Shishmareva Bay (Seward Peninsula). In the west, the Pacific Ocean is limited by the Asian mainland, in the southwest - by the shores of the islands of Sumatra, Java, Timor, then - by the eastern coast of Australia and a conventional line crossing the Bass Strait and then following along the shores of the island of Tasmania, and to the south along a ridge of underwater rises to Cape Alden on Wilkes' Land. The eastern limits of the ocean are the shores of North and South America, and to the south there is a conventional line from the island of Tierra del Fuego to the Antarctic Peninsula on the continent 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 km 2, including marginal seas.
The ocean has a spherical shape, especially pronounced in the northern and eastern parts. Its greatest latitudinal extent (about 10,500 miles) is noted along the parallel of 10° N, and its greatest length (about 8,500 miles) falls on the meridian 170° W. Such large distances between the northern and southern, western and eastern shores are an essential natural feature of this ocean.
The ocean coastline is heavily indented in the west, while in the east the shores 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, 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, shelves occupy about 17% of the entire transition zone. The continental slopes are steep, often stepped, dissected by submarine canyons. The ocean bed occupies a huge space. A system of large uplifts, ridges and individual mountains, wide and relatively low shafts, it is divided into large basins: North-Eastern, North-Western, East Mariana, West Carolina, Central, South, etc. The most significant East Pacific Rise is included in the world's system of mid-ocean ridges. In addition to it, large ridges are common in the ocean: Hawaiian, Imperial Mountains, Caroline, Shatsky, etc. A characteristic feature of the topography of the ocean floor is that the greatest depths are confined 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 zones from the northern subpolar to the southern polar, which determines the diversity of its climatic conditions. At the same time, the most significant part of the ocean space, located between 40° N. w. 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 part. Due to the cooling influence of the Asian continent and the predominance of west-east transport, the temperate and subtropical latitudes of the western part of the ocean are characterized by typhoons, especially frequent in June-September. The northwestern part of the ocean is characterized by monsoons.
Its exceptional size, unique shape, and large-scale atmospheric processes largely determine the characteristics of the hydrological conditions of the Pacific Ocean. Since quite a 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 large river runoff cause a lower salinity of surface waters than in other oceans, the average value of which is 34.58% o.
Temperature and salinity on the surface vary both over the water area and over the seasons. Temperature changes most noticeably over the seasons in the western part of the ocean. Seasonal variations in salinity are small throughout. Vertical changes in temperature and salinity are observed mainly in the upper, 200-400-meter layer. At great depths they are insignificant.
The general circulation in the ocean consists of horizontal and vertical movements of water, which can be traced to one degree or another 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 Northern Trade Wind, Kuroshio, North Pacific warm currents, California, Kuril cold and Alaskan warm currents. The system of circular currents in the southern regions of the ocean includes the warm South Passat, East Australian, zonal South Pacific and cold Peruvian. The rings of currents of the northern and southern hemispheres throughout the year separate the Intertrade Current, passing north of the equator, in the band between 2-4° and 8-12° N latitude. The speeds of surface currents vary in different areas of the ocean and vary with the seasons. Vertical water movements of different mechanisms and intensity are developed throughout the ocean. Density mixing occurs in the surface horizons, especially significant in areas of ice formation. In zones 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 the most important factors in the 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 the social and economic conditions characterized by the EGP of the Pacific Ocean. In relation to land areas gravitating towards the ocean, 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 facing the Pacific Ocean include Russia, China, Vietnam, the USA, Canada, Japan, Australia, Colombia, Ecuador, Peru, etc. 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 significantly remote 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 still it significantly influences the nature of our connections with this ocean.
Almost all mainland states and many island states, with the exception of Japan, adjacent to the Pacific Ocean, have large reserves of various natural resources that are being intensively developed. Consequently, 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 ocean coast and the confinement of their consumption to certain areas is a characteristic feature of the EGP of the Pacific Ocean.
Continents and partly islands over vast areas 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 broad front to the waters of the Indian Ocean, and through the Strait of Magellan and the Drake Passage 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 Antarctic regions, is connected in a relatively small part with other oceans. The routes and its communications with the Indian Ocean pass through the Australasian 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, and the remoteness of vast areas of Antarctic waters from major world centers reduce the transport capabilities of the Pacific Ocean. This is an important feature of its EGP in relation to world sea routes.
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 issues of its evolution remain unclear. Regarding the Pacific Ocean, there is much indirect evidence indicating that the paleo-Pacific Ocean has existed since the mid-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 ophiolitic 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 the development of the ocean in Mesozoic and Cenozoic times has been more or less reliably restored.
The Mesozoic stage appears to have 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 young Indian and Atlantic oceans opened. The expansion 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, in an almost continuous strip. At this stage of the development of the Pacific Ocean, a restructuring of its ancient mid-ocean ridges took place.
The formation of folded structures in northeast Asia and Alaska in the late Mesozoic separated the Pacific Ocean from the Arctic Ocean. In the east, the development of the Andean belt absorbed the island arcs.
Cenozoic stage
The Pacific Ocean continued to shrink due to continents pushing against 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 region. The marginal seas of the northwestern waters also formed, and the island arcs of this part of the ocean acquired their modern appearance. In the north, with the formation of the Aleutian island arc, the Bering Sea became detached, the Bering Strait opened, and the cold waters of the Arctic began to flow into the Pacific Ocean. Off the coast of Antarctica, basins of the Ross, Bellingshausen and Amundsen seas took shape. There was a major fragmentation of the land connecting Asia and Australia, with the formation of numerous islands and seas of the Malay Archipelago. The marginal seas and islands of the transition zone to the east of Australia have acquired a modern appearance. 40-30 million years ago, an isthmus formed between the Americas, and the connection between the Pacific Ocean and the Atlantic Ocean in the Caribbean region was completely interrupted.
Over the past 1-2 million years, the size of the Pacific Ocean has decreased very slightly.
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 continents, transition zones, the ocean floor and mid-ocean ridges. But the general plan of the bottom relief, 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 significantly less compared to other oceans. The continental shallows (shelf) account for 5.4%.
The shelf, like the entire underwater margin of the continents, reaches its greatest development in the western (Asian-Australian) continental 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 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, and is cut through by large underwater canyons. The continental base is a narrow trail of accumulation of products carried out by turbidity currents and landslide masses.
To the north of Australia there is a vast continental shelf with widespread development of coral reefs. In the western part of the Coral Sea there is a unique structure on Earth - the Great Barrier Reef. This is an intermittent 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 during the 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 like an almost vertical wall towards the continental slope.
The underwater margin of New Zealand represents a unique structure. The New Zealand plateau consists of two flat-topped rises: Campbell and Chatham, separated by a depression. The underwater plateau is 10 times larger than the area of the islands themselves. This is a huge block of continental-type earth's crust, with an area of about 4 million km 2, not connected to any of the nearest continents. On almost all sides the plateau is limited by the continental slope, which turns into the foot. This peculiar structure, called the New Zealand microcontinent, has existed at least since the Paleozoic.
The submarine margin of North America is represented by a narrow strip of leveled shelf. The continental slope is heavily indented by numerous submarine canyons.
The area of the underwater margin located to the west of California and called the California Borderland is unique. The bottom relief here is large-block, characterized by a combination of underwater hills - horsts and depressions - grabens, the depths of which reach 2500 m. The nature of the borderland relief is similar to the relief of the adjacent land area. It is believed that this is a highly fragmented part of the continental shelf, submerged to different depths.
The underwater margin of Central and South America is distinguished by a very narrow shelf only a few kilometers wide. Over a long distance, the role of the continental slope here is played by the continental side of the deep-sea trenches. The continental foot is practically not expressed.
A significant part of the continental shelf of Antarctica is blocked by ice shelves. The continental slope here is distinguished by its large width and dissected 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 compared to other oceans. This is a natural combination of basins of marginal seas, island arcs and deep-sea trenches.
In the Western Pacific (Asian-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-Philippine region is complex, including the South China Sea, the seas and island arcs of the Malay Archipelago and deep-sea 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 arranged in several echelons. To the north of the Solomon Islands there is a narrow depression with depths of up to 4000 m, on the eastern extension of which the Vityaz Trench (6150 m) is located. OK. Leontyev identified this area as a special type of transition zone - Vityazevsky. A feature of this area is the presence of a deep-sea trench, but the absence of an island arc along it.
In the transition zone of the American sector there are no marginal seas, no island arcs, and only the deep-water trenches 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 trenches there is a very high density of earthquake epicenters with a magnitude of up to 7-9 points.
The transition zones of the Pacific Ocean are areas of the most significant vertical division of the earth's crust on Earth: the elevation of the Mariana Islands above the bottom of the trench of the same name is 11,500 m, and the South American Andes above the Peruvian-Chilean trench is 14,750 m.
Mid-ocean ridges (rises). They occupy 11% of the area of the Pacific Ocean and are represented by the South Pacific and East Pacific rises. 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 central position and are significantly shifted to the east and southeast. This 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 trench, 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, significant width (up to 2000 km), an intermittent strip of axial rift valleys with extensive participation in the formation of the relief of transverse fault zones. Subparallel transform faults cut the East Pacific Rise into separate blocks, shifted relative to each other. The entire uplift consists of a series of gentle domes, with the spreading center confined to the middle part of the dome, at approximately equal distances from the faults that bound it to the north and south. Each of these domes is also cut by en-echelon short faults. Large transverse faults cut 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 zones of uplift, but also extend far out onto the ocean floor. Among the largest structures of this type are Mendocino, Murray, Clarion, Clipperton, Galapagos, Easter, Eltanin, etc. The high density of the earth's crust under the ridge, high heat flow values, seismicity, volcanism and a number of others are manifested very clearly, despite the fact that the rift 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 defined 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 the large active San Andreas fault and a number of other faults and depressions within the Cordillera. The formation of the California borderland is probably connected with this.
The absolute elevations of the bottom relief 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. The foot of the slopes is clearly traced along an isobath of 4000 m, and the bottom depths in the framing basins reach 5000-6000 m At the highest parts of the uplift there are islands. Easter and the Galapagos Islands. Thus, the amplitude of uplift above the surrounding basins is generally quite large.
The South Pacific uplift, separated from the East Pacific by the Eltanin fault, is very similar to it in its structure. The length of the Eastern uplift is 7600 km, the Southern uplift 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 characteristics of the bottom topography. The eastern (more precisely, southeastern) part, which occupies 1/5 of the ocean floor, is shallower and less complexly built in comparison with the vast western part.
A large proportion of the eastern sector is occupied by morphostructures that have a direct connection with the East Pacific Rise. Here are its lateral branches - the Galapagos and Chilean uplifts. The large blocky ridges of Tehuantepec, Coconut, Carnegie, Nosca, and Sala y Gomez are confined to zones of transform faults cutting the East Pacific Rise. Underwater ridges divide the eastern part of the ocean floor into a number of basins: Guatemala (4199 m), Panama (4233 m), Peruvian (5660 m), Chilean (5021 m). In the extreme southeastern part of the ocean is the Bellingshausen Basin (6063 m).
The vast western part of the Pacific Ocean floor is characterized by significant structural complexity and a variety of relief forms. Almost all morphological types of underwater bed rises are located here: arched shafts, block mountains, volcanic ridges, marginal rises, individual mountains (guyots).
The arched uplifts of the bottom are wide (several hundred kilometers) linearly oriented swellings of the basaltic crust with an excess of 1.5 to 4 km over the adjacent basins. Each of them is like a giant shaft, cut by faults into a number of blocks. Usually, entire volcanic ridges are confined to the central arched and sometimes to the flank zones of these uplifts. Thus, 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 biggest one is o. Hawaii is a volcanic massif of several fused shield basalt volcanoes. The largest of them, Mauna Kea (4210 m), makes Hawaii the highest of the oceanic islands of the World Ocean. In a northwesterly 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 of the western and central parts of the Pacific Ocean have a common pattern: they form a system of arcuate, subparallel uplifts.
The northernmost arc is formed by the Hawaiian Ridge. To the south is the next one, the largest in length (about 11 thousand km), starting with the Cartographer Mountains, which then turn into the Marcus Necker Mountains (Midpacific), giving way to the underwater ridge of the Line Islands and then turning into the base of the Tuamotu Islands. The underwater continuation of this rise can be traced further east up to the East Pacific Rise, where the island is located at the place of their intersection. 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, and Samoa. Probably, the ridge of the southern islands of Cook and Tubu continues this mountain system. The fourth arc begins with the uplift of the North Caroline Islands, turning into the Kapingamarangi submarine swell. 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 shafts 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, etc. There is an idea (G. Menard, 1966) that many underwater rises of the central part of the Pacific Ocean - relics of the mid-ocean ridge that existed here in the Cretaceous period (called the Darwin Rise), which underwent severe tectonic destruction in the Paleogene. This uplift extended from the Cartographer Mountains to the Tuamotu Islands.
Block ridges are often accompanied by faults that are not associated with mid-ocean rises. In the northern part of the ocean, they are confined to submeridional fault zones south of the Aleutian Trench, along which the North-Western Ridge (Imperial) is located. Block ridges accompany a large fault zone in the Philippine Sea basin. Systems of faults and block 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 framework of the bottom and separate oceanic basins from each other.
The largest basins in the west-central part of the ocean are: Northwestern (6671 m), Northeastern (7168 m), Philippine (7759 m), East Mariana (6440 m), Central (6478 m), West Carolina ( 5798 m), East Carolina (6920 m), Melanesian (5340 m), South Fiji (5545 m), South (6600 m), etc. The bottoms of the Pacific Ocean basins are characterized by low thickness of bottom sediments, and therefore flat abyssal plains are very limited in distribution (the Bellingshausen Basin due to the abundant supply of terrigenous sedimentary material carried from the Antarctic continent by icebergs, the North-Eastern Basin and a number of other areas). The transport of material into other basins is “intercepted” by deep-sea trenches, and therefore they are dominated by the topography of hilly abyssal plains.
The Pacific Ocean bed is characterized by separately located guyots - underwater mountains with flat tops, at depths of 2000-2500 m. On many of them, coral structures arose and atolls formed. The guyots, as well as the large thickness of dead coralline limestones on the atolls, indicate 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 a depth of an average of 5500 m.
Bottom sediments
Bottom sediments of the Pacific Ocean are extremely diverse. In the marginal parts of the ocean on the continental shelf and slope, in marginal seas and deep-sea trenches, and in some places on the ocean floor, terrigenous sediments are developed. They cover more than 10% of the Pacific Ocean floor. Terrigenous iceberg deposits form a strip near Antarctica with a width of 200 to 1000 km, reaching 60° S. w.
Among biogenic sediments, the largest areas in the Pacific Ocean, as in all others, are occupied by carbonate (about 38%), mainly foraminiferal sediments.
Foraminiferal oozes are distributed mainly south of the equator to 60° S. w. In the Northern Hemisphere, their development is limited to the top surfaces of ridges and other elevations, where bottom foraminifera predominate in the composition of these silts. Pteropod deposits are common in the Coral Sea. Coral sediments are located on shelves and continental slopes within the equatorial-tropical zone of the southwestern part of the ocean and occupy less than 1% of the ocean floor area. Shelly shells, consisting mainly of bivalve shells and their fragments, are found on all shelves except the Antarctic. Biogenic siliceous sediments cover more than 10% of the Pacific Ocean floor area, and together with siliceous-carbonate sediments - about 17%. They form three main belts of siliceous accumulation: the northern and southern siliceous diatom oozes (at high latitudes) and the equatorial belt of siliceous radiolarian sediments. In areas of modern and Quaternary volcanism, pyroclastic volcanogenic sediments are observed. An important distinctive feature of the bottom sediments of the Pacific Ocean is the widespread occurrence 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.
Bottom mineral resources
The Pacific Ocean contains 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 m2 (on average 7.3-7.8 kg/m2). 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. The USA and Japan are conducting pilot industrial development of nodules.
Other minerals in the form of nodules include phosphorite and barite.
Industrial 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, and in California. Phosphorites are mined from depths of 80-350 m. There are large reserves of this raw material in the open part of the Pacific Ocean within underwater rises. Baryte nodules were discovered in the Sea of Japan.
Placer deposits of metal-bearing minerals are currently important: rutile (titanium ore), zircon (zirconium ore), monazite (thorium ore), etc.
Australia occupies a leading place in their production; along its eastern coast, placers stretch for 1.5 thousand km. Coastal-sea placers of cassiterite concentrate (tin ore) are located on the Pacific coast of mainland and island Southeast Asia. There are significant placers of cassiterite off the coast of Australia.
Titanium-magnetite and magnetite placers are being developed near the island. Honshu in Japan, Indonesia, the Philippines, the USA (near Alaska), in Russia (near Iturup Island). Gold-bearing sands are known off the west 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 in other places in rift zones, ore-forming hydrotherms (“black smokers”) have been identified - outlets of hot (up to 300-400°C) juvenile waters with a high content of various compounds. Polymetallic ore deposits are being formed here.
Among the 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 of gas and coal are of greatest importance.
Oil and gas shows have been discovered 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, and Russia (in the area of Sakhalin Island). The development of oil and gas resources on the Chinese shelf is promising. The Bering, Okhotsk and Japanese seas are considered promising for Russia.
In some areas of the Pacific shelf there are coal-bearing strata. Coal production from the subsoil of the seabed in Japan accounts for 40% of the total. On a smaller scale, coal is mined by sea in Australia, New Zealand, Chile and some other countries.
The Pacific Ocean is the largest and oldest on our planet. It is so huge that it can easily accommodate all the continents and islands combined and that is why it is often called the Great. The area of the Pacific Ocean is 178.6 million square meters. km, which corresponds to 1/3 of the surface of the entire globe.
general characteristics
The Pacific Ocean is the most important part of the World Ocean, as it contains 53% of its total water volume. It extends from east to west for 19 thousand kilometers, and from north to south - 16 thousand. Moreover, most of its waters are located in southern latitudes, and a smaller part - in northern latitudes.
The Pacific Ocean is not only the largest, but also the deepest body of water. The maximum depth of the Pacific Ocean is 10994 m - this is exactly the depth of the famous Mariana Trench. The average figures fluctuate within 4 thousand meters.
Rice. 1. Mariana Trench.
The Pacific Ocean owes its name to the Portuguese navigator Ferdinand Magellan. During his long journey, calm and calm weather reigned across the oceanic expanses, without a single storm or storm.
The bottom topography is very diverse.
Here you can find:- basins (Southern, Northeastern, Eastern, Central);
- deep-sea trenches (Mariana, Philippine, Peruvian;
- elevations (East Pacific Rise).
The properties of water are formed through interaction with the atmosphere and are largely subject to change. The salinity of the Pacific Ocean is 30-36.5%.
It depends on the location of the waters:- maximum salinity (35.5-36.5%) is characteristic of waters in tropical zones, where relatively little precipitation is combined with intense evaporation;
- salinity decreases to the east under the influence of cold currents;
- salinity also decreases under the influence of heavy precipitation, this is especially noticeable at the equator.
Geographical position
The Pacific Ocean is conventionally divided into two regions - southern and northern, the border between which lies along the equator. Since the ocean is colossal in size, its boundaries are the coasts of several continents and partially bordering oceans.
In the northern part, the border between the Pacific and Arctic Oceans is the line connecting Cape Dezhnev and Cape Prince of Wales.
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Rice. 2. Cape Dezhnev.
In the east, the Pacific Ocean borders the coasts of South and North America. A little further south, the boundary between the Pacific and Atlantic Oceans extends from Cape Horn to Antarctica.
In the west, the waters of the Pacific Ocean wash Australia and Eurasia, then the border runs along the Bass Strait on the eastern side, and descends along the meridian south to Antarctica.
Climate Features
The climate of the Pacific Ocean is subject to general latitudinal zonality and the powerful seasonal influence of the Asian continent. Due to its huge area, the ocean is characterized by almost all climatic zones.
- Northeast trade winds reign in the tropical and subtropical zones of the northern hemisphere.
- The equatorial zone is characterized by calm weather throughout the year.
- In the tropics and subtropics of the southern hemisphere, the southeast trade wind dominates. In the summer, tropical hurricanes of incredible strength - typhoons - arise in the tropics.
The average air temperature in the equatorial and tropical zones is 25 Celsius. On the surface, the water temperature fluctuates between 25-30 C, while in the polar regions it drops to 0 C.
Near the equator, precipitation reaches 2000 mm, decreasing to 50 mm per year near the coast of South America.
Seas and islands
The Pacific coastline is most indented in the west, and least in the east. In the north, the Strait of Georgia cuts deeply into the mainland. The largest Pacific bays are California, Panama and Alaska.
The total area of the seas, bays and straits belonging to the Pacific Ocean occupies 18% of the total ocean area. Most of the seas are located along the coasts of Eurasia (Okhotsk, Bering, Japanese, Yellow, Philippine, East China), along the Australian coast (Solomonovo, New Guinea, Tasmanovo, Fiji, Coral). The coldest seas are located near Antarctica: Ross, Amundsen, Somov, D'Urville, Bellingshausen.
Rice. 3. Coral sea.
All rivers of the Pacific Ocean basin are relatively short, but with rapid water flow. The largest river flowing into the ocean is the Amur.
There are about 25 thousand large and small islands in the Pacific Ocean, with unique flora and fauna. For the most part, they are located in equatorial, tropical and subtropical natural complexes.
The large archipelagos of the Pacific Ocean include the Hawaiian Islands, the Philippine archipelago, Indonesia, and the largest island is New Guinea.
An urgent problem in the Pacific Ocean is the significant pollution of its waters. Industrial waste, oil spills, and thoughtless destruction of ocean inhabitants can cause irreparable harm to the Pacific Ocean, upsetting the fragile balance of its ecosystem.
What have we learned?
When studying the topic “Pacific Ocean”, we became acquainted with a brief description of the ocean and its geographical location. We found out which islands, seas and rivers belong to the Pacific Ocean, what are the characteristics of its climate, and became familiar with the main environmental problems.
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The area of the Pacific Ocean with seas is 178.7 million km 2, which is about half the water area of the World Ocean or more than 1/3 of the surface of the globe. The shape of the ocean is isometric, slightly elongated from northwest to southeast. Its length from north to south is about 16,000 km, from west to east up to 20,000 km. It contains about 710.4 million km 3 of water, which corresponds to 53% of the volume of water in the World Ocean. 78.9% of its area falls at depths from 3000 to 6000 m. The average depth of the ocean is 3976 m, the maximum is 11,022 m.
In the west, the ocean boundary runs along the coast of Asia, the Strait of Malacca, the western and southern outskirts of the Malay Archipelago, New Guinea, Torres Strait, the coast of Australia, Bass Strait, the island of Tasmania and further along the meridian of the Southern Cape until it intersects with Antarctica, in the south - along the coast Antarctica, in the east - along the Drake Passage from Cape Sternek on the Antarctic Peninsula to Cape Horn in the Tierra del Fuego archipelago, along the coast of South and North America, in the north - along the Bering Strait.
The contours of the coastline are very complex on the western periphery of the ocean and relatively simple on the eastern. In the west, the transition zone between the ocean floor and the continents is represented by a complex complex of marginal and interisland seas, island arcs and deep-sea trenches. The most significant horizontal and vertical division of the earth's crust on Earth is observed here. In the east, the coasts of North and South America are slightly indented, there are no marginal seas or large clusters of islands, and deep-sea trenches are located directly off the continents.
The peculiarities of the geographical location and the huge size of the Pacific Ocean help to reduce the cooling effect of the waters of the Arctic Ocean, but increase the influence of Antarctica, and therefore the northern part of the ocean is warmer than the southern one. Most of the ocean is located in equatorial tropical latitudes, making it the warmest of all the oceans. The position of the ocean in all latitudes determines the diversity of its natural conditions and resources, as well as the identification within its boundaries of all physical-geographical zones, with the exception of the Arctic.
In the Pacific Ocean there are many islands of different origin, area and configuration. In terms of their number and total area (about 3.6 million km), it ranks first among the oceans. Volcanic islands are found throughout the ocean (Aleutian, Kuril, Ryukyu, Hawaiian, Chatham, Easter, Galapagos, etc.) Continental islands are located mainly in the western part of the ocean (Sakhalin, Japanese, Taiwan, large islands of the Malay archipelago, New Zealand and etc.). Biogenic islands are located mainly in equatorial-tropical latitudes (Carolina, Marshall, Gilbert, Fiji, Tuamotu, etc.). The islands of the central and southwestern parts of the ocean are united under the general name Oceania.
Geological structure and bottom topography. Underwater continental margins occupy 18.2 million km 2 or about 10.2% of the area of the Pacific Ocean, including 5.4% on the shelf, 3.0% on the continental slope and 1.8% on the continental foot. They are most widely represented in the marginal seas of the western continental sector, the region of the Malay Archipelago, and off the northern and eastern coasts of Australia.
In the Bering Sea, about half of the bottom area is on the shelf with shallow depths and leveled relief. It is characterized by the presence of traces of flooded river valleys and relict forms of glacial relief reworked by later marine abrasion-accumulative processes. The continental slope is relatively wide with signs of fault-block dissection and large submarine canyons. The continental foot is weakly expressed, in the form of a uniform and narrow accumulative trail.
On the shelf of the Sea of Okhotsk, a coastal shelf is clearly distinguished, which is an abrasion-accumulative plain limited by an isobath of 100 m and a submerged shelf, occupying the entire central part of the sea with individual depressions up to 1000-1500 m. The continental slope is narrow and steep, indented by underwater canyons and depressions of turbidity flows. . The continental foot is a narrow plain formed by the products of turbidity flows and landslide masses. In the Sea of Japan, the shelf is poorly defined and occupies a significant area only in the Tartary Strait. The continental slope is represented by a narrow strip of steeply inclined bottom. The shelf relief of the East China and Yellow Seas is leveled due to thick alluvial deposits of the Yangtze and Yellow Rivers. Only in the coastal strip are sand ridges formed by tidal currents common. In the South China Sea and the seas of the Malay Archipelago, the underwater margin of the continents is also well developed. Coral structures and accumulation features of carbonate and pyroclastic sediments play a significant role in the structure of shelf zones.
To the north of Australia there is a vast shelf characterized by widespread carbonate sediments and coral reefs. East of Australia lies the world's largest lagoon, separated from the sea by the world's largest barrier reef. The Great Barrier Rift is an intermittent strip of coral reefs and islands, shallow bays and straits, extending in the meridional direction for almost 2500 km, with a width of about 2 km in the northern part, and up to 150 km in the southern part. In the east, the reef breaks off like an almost vertical wall towards the continental slope. A unique morphostructure of Paleozoic age is the New Zealand Plateau, which is a block of continental crust not connected to the mainland. On almost all sides, the plateau is bounded by a wide continental slope, dissected by underwater canyons, gradually turning into the foot.
The relief of the underwater margin of North America is characterized by significant fragmentation, the presence of numerous depressions, flat-topped hills, and wide transverse valleys. Off the coast of Alaska, it shows traces of glacial processing. The relief of the California borderland is characterized by maximum fragmentation, with well-defined tectonic dissection. The shelf is narrow and limited by a ledge at depths of 1000-1500 m. The continental slope is cut by numerous underwater canyons, the alluvial cones of which form the inclined plain of the continental foot. Off the coast of Central and South America, the shelf is very narrow, up to several kilometers wide. South of 40° S. w. it expands somewhat, but is greatly fragmented. The role of the continental slope is played by the continental sides of deep-sea trenches. The continental foot is practically not expressed.
The continental margin of Antarctica is distinguished by the deep position of the shelf edge (mainly up to a depth of 500 m), dissected relief, and a wide distribution of glacial and iceberg deposits. The continental slope is wide, cut by underwater canyons. The well-developed continental base is represented by a gently undulating sloping plain.
Transition zone areas The Pacific Ocean occupy 13.5% of its area and represent a natural combination of basins of marginal seas, island arcs and deep-sea trenches. They are at different stages of development and differ in the set, configuration and arrangement of these components. They are characterized by the complex structure of the earth's crust belonging to the geosynclinal type. Seismic and together form the Pacific Ring of earthquakes and modern volcanism.
In the Western Pacific sector, the following transition regions are distinguished: Aleutian, Kuril-Kamchatka, Japanese, East China, Indonesian-Philippines, Bonin-Mariana, Malesian, Vityazevskaya, Tongo-Kermadec and Macquarie. In this part of the ocean, younger transitional areas are located on the border with the ocean floor, those at a later stage of development are located closer to the continents or are separated from the ocean floor by well-developed island arcs (Aleutian, Kuril-Kamchatka) and islands with continental crust (Japanese) .
There are two transition regions in the East Pacific sector: Central American and Peruvian-Chilean. Here the transition zone is expressed only by deep-sea trenches. There are no marginal seas or island arcs. The role of island arcs in this zone is played by young folded structures of Central and South America.
Mid-ocean ridges occupy 11% of the area of the Pacific Ocean and are represented by the South Pacific and East Pacific rises. Essentially, it is a single structure, approximately 11,700 km long, which is part of the planetary system of mid-ocean ridges. They are characterized by an arched structure, significant width (up to 2000 km), and an intermittent strip of axial rift valleys intersected by transverse transform faults. The rift system of the axial zone is less pronounced than in the Mid-Atlantic and other ridges of this type. But such features of the structures under consideration, such as the high density of the earth’s crust under the ridge, seismicity, volcanism, high values of heat flow and a number of others, appear very clearly. North of the equator, the East Pacific Rise narrows. The rift zone of the ridge becomes more pronounced. In the California region, this structure invades the mainland. This is associated with the formation of the California borderland, the large active San Andreas fault, the Sacramento and Yosemite Valley depressions, the block structures of the Great Basin and the main rift of the Rocky Mountains. The mid-ocean rises of the Pacific Ocean have lateral branches in the form of the Chilean rise and the Galapagos rift zone. In addition, the system of mid-ocean ridges includes the Gorda, Juan de Fuca and Explorer underwater ridges located in the northeast of the ocean. Mid-ocean ridges are characterized by rift-type crust, which is denser than oceanic crust.
Bed of the Pacific occupies 65.5% of its area and is almost entirely located within the oceanic lithospheric plate, the surface of which is located on average at a depth of 5500 m. Mid-ocean rises divide the ocean bed into two parts differing in size and features of the bottom topography. The eastern part is occupied by extensive basins and morphostructures associated mainly with the East Pacific Rise. The western sector is characterized by a more complex structure and variety of relief forms. Almost all morphological types of underwater rises of the ocean floor are found here: oceanic swells, block mountains, volcanic ridges, marginal swells and ridges, individual mountains (guyots). The ridges and rises of the Pacific Ocean are separated from each other by ocean basins. The main ones are: Northwestern (6671 m), Northeastern (7168 m), Philippine (7759 m), Eastern Mariana (6440 m), Central (6478 m), Western Carolinian (5798 m), Eastern -Carolinian (6920 m), Melanesian (5340 m), Southern (6600 m), Chilean (5021 m) and Bellingshausen (5290 m). The bottom topography of the basins is characterized by hilly, sometimes flat (Bellingshausen Basin) abyssal plains, individual underwater peaks, guyots and latitudinal faults with a length of up to 4000-5000 km. The largest faults are confined to the Northeast Basin: Mendocino, Murray, Molokai, Clarion, Clipperton. Significant faults in the eastern part of the ocean are also found south of the equator: Galapagos, Marquesas, Easter, Challenger.
The basins and uplifts of the Pacific Ocean floor correspond to oceanic-type crust. The granite layer is replaced by a “second layer” consisting of compacted sedimentary or volcanic rocks. The thickness of the sedimentary layer varies from 1000 to 2000 m, and in some places it is absent. The thickness of the “second layer” ranges from several hundred to several thousand meters; in some areas it is also absent. The average thickness of the basalt layer is about 7000 m.
Bottom sediments and minerals The Pacific Ocean is very diverse. Terrigenous sediments occupy about 10% of the Pacific Ocean floor area. They are mainly confined to the underwater margins of continents, but are also found in marginal seas, deep-sea trenches, and even in certain areas of the ocean floor. Terrigenous iceberg deposits form a strip up to 1000 km wide off the coast of Antarctica. Of the biogenic sediments, the most common are carbonate foraminiferal sediments (about 38%), occupying significant areas of the bottom south of the equator to 60° S. w. In the northern hemisphere, their development is limited to the top surfaces of ridges and other elevations, and the silts are dominated by bottom foraminifera. Pteropod deposits occupy several areas of the floor in the Coral Sea. Coral sediments occupy less than 1% of the ocean area and are located on shelves and continental slopes in the equatorial-tropical zone. Shell sediments are found on all shelves except the Antarctic. Biogenic siliceous sediments cover more than 10% of the bottom area and form three main belts: northern and southern siliceous diatomaceous oozes in high latitudes and equatorial siliceous radiolarians. In areas of modern and Quaternary volcanism, pyroclastic deposits are observed. Due to the predominance of depths of more than 4500-5000 m, significant areas of the bottom in the Pacific Ocean (about 35%) are covered with deep-sea red clay.
Iron-manganese nodules are distributed almost everywhere on the Pacific Ocean bed, occupying an area of about 16 million km 2. The average content of nodules is 7.3-7.8 kg/m2, and in some areas of the ocean reaches 70 kg/m2. Their total reserves are estimated at 17 thousand billion tons. The United States and Japan are conducting pilot industrial development of iron-manganese nodules. Other minerals in the form of nodules include phosphorite and barite. Industrial reserves of phosphorites have been found off the Californian coast, on the shelf of the Japanese Islands, off the coast of Peru and Chile, New Zealand, on underwater rises of the open ocean and other areas. Potential reserves of this raw material are estimated at hundreds of billions of tons.
The placer deposits of metalliferous minerals discovered in the Pacific Ocean are of great importance: rutile (titanium ore), zircon (zirconium ore), monocyte (thorium ore) and others. The leading place in their production is occupied by Australia, where placers stretch for 1.5 thousand km along the eastern coast. Coastal-marine placers of cassiterite (tin ore) are located on the Pacific coast of Southeast Asia and Australia. Titanium-magnetite and magnetite (iron ore) placers are mined in the area of the Japanese Islands, the Malay Archipelago, the Kuril Ridge and the coast of Alaska. Deposits of gold-bearing sands were discovered off the western coast of North (Alaska, California) and South (Chile) America. 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 other regions in the area of rift zones, ore-forming hydrotherms have been identified.
Among non-metallic mineral resources, it is worth noting deposits of glauconite, pyrite, dolomite, building materials: gravel, sand, clay, limestone-shell rock, etc. Significant oil and gas deposits have been discovered in many areas of the Pacific shelf zone. In some areas of the shelf off the coast of Japan, Australia, New Zealand and South America, there are seams of coal.
Climate The Pacific Ocean is determined by planetary patterns of distribution solar radiation and atmospheric circulation.
The annual amount of total solar radiation varies from 3000-3200 MJ/m 2 in subarctic and Antarctic latitudes to 7500-8000 MJ/m 2 in equatorial tropical latitudes. The value of the annual radiation balance ranges from 1500-2000 to 5000-5500 MJ/m2. In January, a negative radiation balance is observed north of the line: the middle part of the Sea of Japan - the southern tip of the island. Vancouver (up to -80 MJ/m2); in July – south of 50° S. w. The balance reaches its maximum monthly value (up to 500 MJ/m2) in the tropical region, in January in the southern hemisphere, and in July in the northern hemisphere.
In the temperate latitudes of the northern hemisphere there is the Aleutian minimum, which is more pronounced in winter. In the subpolar region of the southern hemisphere, the Antarctic low pressure belt is distinguished. In the subtropical latitudes of both hemispheres above the ocean there are centers of two constant baric maxima: the North Pacific (Hawaiian) and the South Pacific. Along the equator there is an equatorial depression. The formation of the climate of the Pacific Ocean is also influenced by pressure centers that form over the adjacent continents: the seasonal Asian maximum (winter), the reversible Australian pressure center (maximum in winter and minimum in summer of the southern hemisphere) and the permanent Antarctic high pressure area.
Wind systems are formed in accordance with the distribution of the main pressure centers. Subtropical highs and equatorial depressions determine the formation of trade winds in tropical latitudes. The frequency of trade winds in the southern hemisphere is about 80%, at a speed of 6-15 m/s (sometimes up to 20 m/s), in the northern hemisphere up to 60-70%, at a speed of 6-10 m/s. Calm weather prevails in the trade wind convergence zone. In temperate latitudes, westerly winds are most characteristic, especially in the southern hemisphere, where they are strongest and most constant. In high latitudes off the coast of Antarctica, easterly winds are observed. The northwestern Pacific Ocean has a pronounced monsoon circulation. Winter north and north-west winds give way to south and south-east winds in summer. Maximum wind speeds are associated with the passage of tropical cyclones. The areas of their occurrence lie between 20 and 5° latitude in each hemisphere, with a maximum frequency in summer and autumn. The largest number of tropical cyclones in the Pacific Ocean is observed in the area located between the Yellow Sea, the Philippine Islands and 170° east. d. On average, there are 27 typhoons per year, in some years up to 50, of which about half have hurricane-force wind speeds of more than 33 m/s.
Average air temperature February in equatorial latitudes is + 26 – + 28 °C, off the coast of Antarctica it drops to -10 °C, and in the Bering Strait to -20 °C. The average temperature in August varies from 26 – + 28 °C at the equator to +5 °C in the Bering Strait and to -25 °C near Antarctica. Maximum air temperatures (up to +36 – +38 °C) are observed in the northern tropic region east of the Philippine Sea, as well as off the Californian and Mexican coasts. Minimum temperatures are observed in Antarctica (up to -60 °C). The highest annual temperature amplitudes are typical for the northwestern monsoon region off the coast of Asia - 20-25 °C. At equatorial latitudes, the amplitude does not exceed 2-4 °C.
The distribution of air temperature over the ocean is significantly influenced by continents, prevailing winds and ocean currents. Within the equatorial-tropical zone, the western part of the Pacific Ocean, with the exception of the area adjacent to Asia, is warmer than the eastern part. In the temperate latitudes of the northern hemisphere, on the contrary, the west is colder than the east. In the temperate zone of the southern hemisphere, such differences are not observed.
Average annual cloudy over the Pacific Ocean reaches maximum values in temperate latitudes – 7-9 points. In equatorial regions it is somewhat lower and amounts to 6-7 points. In the zone of influence of subtropical baric maxima, cloudiness decreases to 3-5 points, and in certain areas of the southern hemisphere - to 1 point.
Largest quantity precipitation falls in the equatorial-tropical trade wind convergence zone, where intense ascending air currents develop. Here the annual precipitation exceeds 3000 mm. In temperate latitudes, precipitation ranges from 1000 mm in the west to 2000 in the east of the ocean. The least amount of precipitation falls in the zone of action of the eastern periphery of subtropical pressure maxima, where downward air currents dominate and cold ocean currents pass. To the west of the California Peninsula, the annual precipitation does not exceed 300 mm, and off the coast of Peru and northern Chile it is 100 and even 30 mm. In the western parts of subtropical regions, precipitation increases to 1000-2000 mm. In the high latitudes of both hemispheres, due to low air temperatures and low evaporation, the amount of precipitation decreases to 300 mm in the north and 100 in the south. In the intertropical convergence zone and subtropical high pressure areas, precipitation falls almost evenly throughout the year. In the area of the Aleutian Low, as well as in the temperate and subpolar latitudes of the southern hemisphere, the frequency of precipitation increases in winter. In the monsoon region of the northwestern Pacific Ocean, maximum precipitation occurs in summer.
Fogs most often form in temperate latitudes, especially over the waters adjacent to the Kuril and Aleutian Islands, where the average annual number of days with fog reaches 40, with a maximum in the summer. In temperate latitudes of the southern hemisphere, their number generally does not exceed 10-20 days.
Hydrological regime. Location surface currents in the Pacific Ocean is mainly determined by the peculiarities of atmospheric circulation over its waters and adjacent continents. In the ocean, circulation systems similar to atmospheric ones and genetically determined by them are formed. North of 40°N. a subpolar cyclonic gyre stands out, consisting of the Alaskan, Aleutian, Kamchatka, Kuril and North Pacific currents. To the south of this current system is a subtropical anticyclonic gyre formed by the Sulfur Trade Wind, Kuroshio, North Pacific and California currents. At low latitudes, the Northern Trade Wind, Inter-Trade Wind (Equatorial Countercurrent) and Southern Trade Wind Currents form two narrow tropical cyclonic gyres. In the Southern Hemisphere there is also a subtropical anticyclonic gyre, consisting of the Southern Trade Wind, East Australian, Western Winds and Peruvian Currents. The West Winds current interacts with the weakly expressed coastal Antarctic Current in the eastern direction, forming a southern subpolar cyclonic gyre. Alternating anticyclonic and cyclonic current gyres are not completely closed systems. They interact with each other and are connected through common currents.
An important role in the circulation of Pacific Ocean waters belongs to the subsurface compensation Cromwell Current, moving under the South Trade Wind Current at a depth of 50-100 m in an easterly direction. The length of this current is about 7000 km, width is approximately 300 km and speed is from 1.8 to 3.3 km/h. The average speed of most main surface currents is 1-2 km/h, Kuroshio and Peruvian up to 3 km/h.
The Pacific Ocean produces the highest wind waves(up to 34 m). Increased wave activity is observed between 40-50° N. w. and 40-60° S. sh., where during a storm the wave length reaches 100-120 m, height 6-8 m, sometimes up to 15-20 m, with a period of 10 s. The area with maximum storm activity is located between Antarctica and New Zealand in the vicinity of Macquarie Island, with an average wave height of about 3 m. Tsunamis are quite often observed in the area of the islands and the coast of the Asian continent in the northern and northwestern parts of the ocean, as well as off the coast of South America .
Irregular semidiurnal patterns are observed across much of the Pacific Ocean. tides. Regular semidiurnal tides prevail in the southern part of the ocean. Small areas in the equatorial region and in the north (Kuril Islands, eastern Kamchatka) have daily tides. The average tidal wave value is 1-2 m. In the bays of the Gulf of Alaska - 5-7 m, in Cook Bay - up to 12 m. The maximum tidal value was recorded in Penzhinskaya Bay (Sea of Okhotsk) - 13.2 m.
The Pacific Ocean is the warmest of the oceans. Average annual temperature his surface waters is 19.1°C. This is due to the enormous size of the ocean, the location of most of it (about 50%) in equatorial tropical latitudes and significant isolation from the Arctic Ocean.
The temperature distribution of surface waters of the Pacific Ocean is determined mainly by heat exchange with the atmosphere and water circulation, which often disrupts the sublatitudinal variation of isotherms. The highest annual and seasonal water temperatures are observed in equatorial-tropical latitudes – +25 – +29 °C. In equatorial-tropical and subtropical zones, the western part of the ocean is 2-5 °C warmer than the eastern part. In temperate and subpolar latitudes of the northern hemisphere, throughout the year, the western sector of the ocean is 3-7 °C colder than the eastern one. In summer, the water temperature in the Bering Strait is +5 – +6 °C. In winter, the border of negative temperatures passes in the middle part of the Bering Sea. In the temperate and polar latitudes of the southern hemisphere there are no significant differences in water temperature between the western and eastern parts of the ocean. In the Antarctic floating ice area, the water temperature, even in summer, rarely rises to +2 – +3 °C. In winter, negative water temperatures are observed south of 60-62°S. w.
Salinity distribution The waters of the Pacific Ocean are determined mainly by moisture exchange processes on the surface and water circulation. The water balance of the ocean is characterized by a significant excess of atmospheric precipitation and river flow over evaporation. The salinity of its waters at all depths is lower than in other oceans. The highest salinity values of surface waters are observed in the subtropics up to 35.5 ‰ in the Northern Hemisphere and up to 36.5 ‰ in the Southern. In the equatorial zone, salinity decreases to 34.5 ‰ or less, in high latitudes - to 31-30 ‰ in the north and up to 33 ‰ in the south. Along the coast in the east of the ocean, currents carry less saline waters from high latitudes to lower latitudes, and in the west - more saline waters from low to high latitudes.
Ice formation in the Pacific Ocean occurs in the Antarctic regions, as well as in the Bering, Okhotsk, Japanese and Yellow Seas, the Gulf of Alaska, the bays of the eastern coast of Kamchatka and the island of Hokkaido. There is no multi-year ice in the northern part of the ocean. The maximum age of ice is 4-6 months, thickness is 1-1.5 m. Floating ice does not fall below 40° N. w. at o. Hokkaido and 50° N. w. off the eastern shores of the Gulf of Alaska. There is virtually no ice removal from the Arctic Ocean. In the northern Gulf of Alaska there are several coastal glaciers (Malaspina), which form small icebergs. Typically, ice in the northern part of the ocean is not a serious obstacle to ocean navigation. In the southern part of the ocean, large masses of ice are constantly present, and all types of ice extend far to the north. The average limit of floating Antarctic ice in winter lies in the region of 61-64° S. w. In some years with severe winters, the ice extends to 56-60° S. w. In summer, the edge of floating ice is located about 70° south. w. Multi-year pack ice, characteristic of the Central Arctic, is absent in Antarctica. The powerful continental glaciers of Antarctica give rise to numerous icebergs that reach 48-48°S. w. The main areas of iceberg formation are the Ross and Amundsen seas. The average size of icebergs is 2-3 x 1-1.5 km, maximum up to 400 x 100 km. The height of the surface part ranges from 10-15 m to 60-100 m.
Transparency water in temperate and Antarctic latitudes of the Pacific Ocean ranges from 15 to 25 meters. In equatorial-tropical latitudes, transparency increases to 30-40 m in the east and to 40-50 m in the west of the ocean.
In the Pacific Ocean the following are distinguished: types of water masses: surface, subsurface, intermediate, deep and bottom. The properties of surface water masses are determined by the processes of heat and moisture exchange on the ocean surface. They have a thickness of 30-100 m and are distinguished by relative uniformity of temperature, salinity, density and seasonal variability of properties. Subsurface waters in the temperate zone are formed as a result of autumn-winter cooling and wind mixing of water, and in warm climates - through the sinking of more saline surface waters. They differ from surface ones in increased salinity and density, with water temperatures in the tropics and subtropics being 13-18 °C, and in temperate latitudes 6-13 °C. Depending on climatic conditions, the depth of their boundary with intermediate waters ranges from 200 to 600 m. Intermediate water masses in the northwestern part of the ocean are formed as a result of the subsidence of cold waters from the Bering Sea, in the Antarctic regions - due to the subsidence of cooled waters on the Antarctic shelf, in other areas - through local climatic conditions and the characteristics of vertical water circulation. In temperate and high latitudes they have a temperature of 3-5°C and a salinity of 33.8-34.7 ‰. The lower boundary of this structural zone is located at a depth of 900 to 1700 m. The deep water masses of the Pacific Ocean are formed mainly as a result of the subsidence of the cold waters of the Antarctic and the Bering Sea with their subsequent spreading over the basins. Their lower boundary passes at a depth of 2500-3000 m. Bottom water masses form on the Antarctic shelf and gradually spread along the bottom, filling all ocean basins. They are characterized by uniform salinity (34.6-34.7 ‰) and low temperature (1-2°C). Deep and bottom water masses make up about 75% of the volume of Pacific Ocean waters.
Due to the huge size of the water area and the diversity of natural conditions organic world The Pacific Ocean is the richest in the number of species, ecological communities, total biomass and commercial biological resources. The phytoplankton of the Pacific Ocean is represented mainly by unicellular algae (about 1300 species), almost all of which belong to peridinians and diatoms. Most vegetation is concentrated in the coastal zone, relatively shallow ocean areas and upwelling areas. High and temperate latitudes of both hemispheres are characterized by massive development of brown algae, especially the kelp group. In equatorial-tropics, fucus, large green (up to 200 m long) and calcareous red algae are widespread. The bottom vegetation of the Pacific Ocean has about 4 thousand species of algae and up to 30 species of flowering plants (sea grasses).
The fauna of the Pacific Ocean is 3-4 times richer in species composition than in other oceans. All groups of animal organisms living in the World Ocean are presented here. The fauna of the western regions of the Pacific Ocean in the equatorial-tropical regions is especially rich in the number of species. In the seas of the Malay Archipelago there are more than 2 thousand species of fish, while in the seas in the north of the ocean only about 300 are known. But even in these waters the number of fish species is twice as large as in similar seas of other oceans. In the area of the Sunda Islands and northeast of Australia, the coral fauna is widely developed. More than 6,000 species of mollusks live in tropical waters. The fauna of the deep-sea parts of the ocean is unique. At depths of more than 8.5 km, 45 species of animals live, of which approximately 70% are endemic. Holothurians, elasmobranchs, polychaetes, brittle stars and other organisms adapted to life in the ultraabyssal predominate here. The fauna of the Pacific Ocean is distinguished by the antiquity of many systematic groups, the endemism and gigantism of their representatives. Ancient sea urchins and fish (Jordan, Gilbertidia, etc.) live here, and endemic mammals - fur seal, sea beaver, sea lion, giant mussels, oysters, the largest bivalve mollusk, tridacna, weighing up to 300 kg.
The Pacific Ocean is characterized by high biological productivity. The distribution of primary production and biomass is determined by latitudinal geographic zonality, the position of the main oceanic water cycles and dynamic zones (convergence, divergence, upwelling). Areas of significant productivity are confined to the subpolar, temperate and equatorial zones (250-500 mg C/m2). Within these zones, the maximum values of primary production and biomass correspond to upwelling zones. In tropical latitudes, bioproductivity is significantly lower (100 mg C/m2 or less). In the central regions of subtropical gyres, it is minimal and does not exceed 50 mg C/m2.
The Pacific Ocean is divided into three biogeographic regions: North Pacific, Tropic-Indo-Pacific and Antarctic. The North Pacific region is characterized by salmon and Far Eastern sardines; Tropic-Indo-Pacific – sharks, flying fish, tuna, etc.; Antarctic - nototenaceae.
The first place among the commercial biological resources of the Pacific Ocean is occupied by fish (85% of the catch), the second place is occupied by mollusks, crustaceans, echinoderms and other non-fishery objects, including algae (10%), and the third place by marine mammals (5%). The Pacific Ocean catches 45% of the world's fish.
The main fishing areas are in the northwestern, northeastern, eastern and southeastern parts of the ocean. These are areas of interaction between the warm waters of the Kuroshio and the cold currents of the Kuril Current, the zone of penetration of the warm Alaskan Current into high latitudes, shelf areas in the western ocean and upwelling zones off the coast of North and especially South America. Since the 70s, fish catches in the Antarctic regions have increased significantly. The main commercial fish of the Pacific Ocean: pollock, anchovy, herring, sardine, horse mackerel, mackerel, saury, salmon, tuna, cod, hake. flounder, halibut, sea bass. Also in the ocean there is fishing for whales and various invertebrates. Mariculture has received significant development, especially recently.
In the Pacific Ocean (according to D.V. Bogdanov, 1991) all physiographic belts with the exception of the Arctic. Due to significant differences in the natural conditions of the western, eastern and central regions of the ocean, within the belts there are physiographic regions. When determining areas, the features of their geographical location, climatic conditions, hydrological regime, the degree of expression of natural processes and phenomena, etc. are taken into account. In the western part of the Pacific Ocean, marginal seas are usually isolated as physiographic regions; in the eastern part, zones of intense upwelling are usually isolated. Northern subpolar belt: Bering Sea, Sea of Okhotsk; northern temperate zone: Gulf of Alaska area, Sea of Japan, Yellow Sea; northern subtropical zone: California region, Kuroshio, East China Sea; northern tropical zone: Philippine region, South China Sea, Gulf of California; equatorial belt: Panama region, Australasian seas, New Guinea Sea, Solomon Sea; southern tropical zone: Peruvian region, Eastern region, Coral Sea with Great Barrier Reef subregion; southern subtropical zone: Tasman Sea; southern temperate zone: Chilean region; southern subpolar belt; south polar zone: Ross Sea.