Pacific Ocean

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Pacific Ocean,

largest and deepest ocean, c.70,000,000 sq mi (181,300,000 sq km), occupying about one third of the earth's surface; named by the explorer Ferdinand MagellanMagellan, Ferdinand
, Port. Fernão de Magalhães, Span. Fernando de Magallanes, c.1480–1521, Portuguese navigator who sailed for Portugal and Spain. Born of a noble family, he was reared as a page in the royal household.
..... Click the link for more information. ; the southern part is also known as the South Sea.

Physical Geography

Extent and Seas

The Pacific Ocean extends from the arctic to antarctic regions between North and South America on the east and Asia and Australia on the west. The international date line passes through it. It is connected with the Arctic Ocean by the Bering Strait; with the Atlantic Ocean by the Drake Passage, Straits of Magellan, and the Panama Canal; and with the Indian Ocean by passages in the Malay Archipelago and between Australia and Antarctica. Its maximum length is c.9,000 mi (14,500 km), and its greatest width c.11,000 mi (17,700 km), between the Isthmus of Panama and the Malay Peninsula. The principal arms of the Pacific Ocean are (in the north) the Bering Sea; (in the east) the Gulf of California; (in the south) Ross Sea; and (in the west) the Sea of Okhotsk, the Sea of Japan, and the Yellow, East China, South China, Philippine, Coral, and Tasman seas. Few large rivers drain into the Pacific Ocean; the largest are the Columbia of North America and the Huang He and Chang (Yangtze) of China.

Coastline and Islands

Along the E Pacific shore, generally, the coast rises abruptly from a deep seafloor to mountain heights on land, and there is a narrow continental shelf. The Asian coast is generally low and indented and is fringed with islands rising from a wide continental shelf. A series of volcanoes, the Circum-Pacific Ring of Fire, rims the Pacific basin.

The approximately 20,000 islands in the Pacific Ocean are concentrated in the south and west. Most of the larger islands are structurally part of the continent and rise from the continental shelf; these include the Japanese island arc, the Malay Archipelago, and the islands of NW North America and SW South America. Scattered around the Pacific and rising from the ocean floor are high volcanic islands (such as the Hawaiian Islands) and low coral islands (such as those of OceaniaOceania
or Oceanica
, collective name for the approximately 25,000 islands of the Pacific, usually excluding such nontropical areas as the Ryukyu and Aleutian islands and Japan, as well as Taiwan, Indonesia, and the Philippines, whose populations are more closely
..... Click the link for more information. ).

Ocean Floor

The floor of the Pacific Ocean, which has an average depth of c.14,000 ft (4,300 m), is largely a deep-sea plain. The greatest known depth (35,798.6 ft/10,911.5 m) is in the Challenger Deep in the Marianas trench c.250 mi (400 km) SW of Guam. Rising from the plain are swells (many of which are volcanic), seamounts, and guyots; the extensive Albatross Plateau covers most of the SE and E central Pacific basin.

Currents

Huge whirls, formed by the major ocean currents, are found roughly north and south of the equator; the Equatorial Counter Current separates them. The northern whirl is formed by the North Equatorial Current, Japan Current, North Pacific Drift, and California Current; the southern whirl is formed by the South Equatorial Current, East Australian Current, West Wind Drift, and Peruvian (or Humboldt) Current. There are many branch and feeder currents that help to constantly circulate ocean water of differing temperatures and salinities.

Commerce and Shipping

The principal commercial fishing areas in the Pacific are found in the shallower waters of the continental shelf; salmon, halibut, herring, sardines, and tuna are the chief catch. Most of the transpacific sea-lanes pass through the Hawaiian Islands; the chief Pacific ports are San Francisco, Los Angeles, Seattle, Tokyo-Yokohama, Guangzhou, Hong Kong, Shanghai, Manila, and Sydney. Since the 1950s many of the South Pacific islands have become tourist centers.

Exploration and Settlement

The Pacific islands of the south and west were populated by migrants from Asia who crossed long distances of open sea in primitive boats, beginning some 3,400 years ago. Polynesian voyagers reached Easter Island, in the E South Pacific perhaps as early as A.D. 800, by which time they had also reached Hawaii. European travelers including Marco Polo had reported an ocean off Asia, and in the late 15th cent. trading ships had sailed around Africa to the western rim of the Pacific, but European recognition of the Pacific as distinct from the Atlantic Ocean dates from Balboa's sighting of its eastern shore (1513).

Magellan's crossing of the Philippines (1520–21) initiated a series of explorations, including those of Drake, Tasman, Dampier, Cook, Bering, and Vancouver, which by the end of the 18th cent. had disclosed the coastline and the major islands. In the 16th cent. supremacy in the Pacific area was shared by Spain and Portugal. The English and the Dutch established footholds in the 17th cent., France and Russia in the 18th, and Germany, Japan, and the United States in the 19th. Sealers and whalers sailed the Pacific from the late 18th cent., and Yankee clippers entered Pacific trade in the early 19th cent.

Bibliography

See G. Soule, The Greatest Depths (1970); E. S. Dodge, Beyond the Capes (1971); J. Gilbert, Charting the Vast Pacific (1971); V. S. Gorshkov, ed., Pacific Ocean (1976).

Pacific Ocean

the world’s largest and deepest ocean, with the continents of Eurasia and Australia to the west, North and South America to the east, and Antarctica to the south. The Pacific Ocean’s boundary with the Arctic Ocean runs through the Bering Strait, from Cape Peek off the Chukchi Peninsula to Cape Prince of Wales off the Seward Peninsula in Alaska. The border between the Pacific and Indian oceans extends along the northern edge of the Strait of Malacca, the western coast of Sumatra, and the southern coasts of Java, Timor, and New Guinea, passes through the Torres and Bass straits, skirts the eastern shore of Tasmania, and, keeping to the underwater ridges, touches Antarctica at Cape Williams on the Oates Coast. The boundary with the Atlantic Ocean stretches from the Antarctic Peninsula, running between the South Shetland Islands, to Tierra del Fuego.

The Pacific Ocean extends for about 15,800 km from north to south and for about 19,500 km from east to west. Including its seas, the Pacific has an area of 179,679,000 sq km, an average depth of 3,984 m, and a water volume of 723,699,000 cu km. (Without the seas, the figures are 165,246,200 sq km, 4,282 m, and 707,555,000 cu km, respectively.) The deepest place in the Pacific Ocean, and in the world ocean, is the Marianas Trench, which descends to 11,022 m. The international date line passes through the Pacific along the 180th meridian.

Seas. Most of the ocean’s seas lie along its northwestern and western edges: the semienclosed Bering Sea, Sea of Okhotsk, Sea of Japan, and East China, Yellow, and South China seas; Japan’s Inland Sea (Seto-naikai); the interisland Sulu, Celebes (Sulawesi), Molucca, Ceram, Banda, Flores, Java, and Savu seas; and the marginal Coral and Tasman seas. In the east the only seas are the Gulf of California, a semienclosed sea, and the marginal Ross, Amundsen, and Bellingshausen seas off the coast of Antarctica.

Islands. In the number and area of its islands, the Pacific Ocean ranks first among the world’s oceans. Many of the Pacific’s 10,000 islands, grouped in archipelagoes and island chains, are found along the ocean’s rim, chiefly in the west. They include the Aleutian and Kuril islands, Sakhalin, the Japanese Islands, the Philippines, the Moluccas, the Sunda Islands, and Fiji, Tonga, and New Zealand. In the open ocean there are numerous islands of volcanic origin (Marquesas, Society Islands, Hawaiian Islands, Samoa, Galápagos) or of coral origin (Marshall Islands, Gilbert Islands, and the islands of Tokelau, Phoenix, Line, and Tuamo-tu). Such islands as Marcus, Wake, Nauru, Ocean, and Tongareva are uplifted reefs.

Coasts. Most of the Pacific coastline is of the fjord or abrasion type. Along the eastern edge of the Pacific, from Puget Sound in North America to Chiloé Island in South America, the coasts are of the abrasion type, slightly indented and hilly. Southward to Cape Horn and northward to the Aleutian Islands, they are of the fjord type. The coasts of the marginal seas of Asia are of the fjord type in the north (along the Bering Sea and Kamchatka). Further south abrasion coasts are found along mountainous stretches and accumulative ones along lowlands. In the west the tropical zone has chiefly coral coasts, with barrier reefs in places. Most of the Antarctic coast is primarily formed by shelf glaciers.

A. M. MUROMTSEV

Topography and geological structure of the bottom. The underwater continental margins that encircle the Pacific Ocean have a complex topography and geological structure. The width of the shelf varies from a few dozen kilometers, along the coast of North and South America, to 700–800 km, in the Bering, East China, and South China seas. The depth of the outer edge of the shelf ranges from 150 to 500 m. The continental slopes—steep, often terraced, and dissected by canyons—are composed of ancient rocks of various ages. Along the Pacific’s northern and western periphery, from the Alaska Peninsula to New Zealand, stretches a system of marginal sea basins, island arcs, and deep-sea trenches, encompassing the region of the Australian and Asian seas and together forming a geosynclinal belt. This vast area is characterized by a contrasting topography, active volcan-ism, intensive seismic activity, and a complex alternation of oceanic, continental, and intermediate crusts. The greatest depths of the sea basins, varying from 3,500 m to 7,500 m, are found in the Bering, Okhotsk, Japan, South China, Sulu, Sulawesi, Philippine, and Coral seas. Many of the basins are complicated by elevations.

The island arcs consist of one or two chains of islands, with no volcanic activity occurring on the outer islands. South of Japan the island arcs are divided into two branches, framing the Philippine Basin. Associated with the island arcs are deep-sea trenches in which are found the ocean’s maximum depths: the Aleutian Trench (7,822 m), the Kuril-Kamchatka Trench (9,717 m), the Japan Trench (8,412 m), the Bonin Trench (9,810 m), the Marianas Trench (11,022 m), the Philippine Trench (10,265 m), and the New Britain (8,320 m), Bougainville (9,103 m), Tonga (10,882 m), and Kermadec (10,047 m) trenches. Along the coasts of South and Central America and Lower California stretch the Peru Trench (6,601 m), the Chile Trench (8,069 m), the Middle America Trench (6,489 m), and the Cedros Trench (6,225 m). Trenches do not occur further north. At the surface of the deep-sea trenches are enormous fractures, steeply inclined toward the continents and penetrating deeply into the mantle (Benioff zones). The Andesite Line, the boundary of andesite volcanic activity, parallels the trenches.

Within the bounds of the ocean bed (of the oceanic plates, or thalassocratons) are vast basins separated by major elevations. Among the largest are the Northeast, Northwest, East Marianas, West Caroline, East Caroline, Melanesia, Central, South, Bellingshausen, Chile, and Peru basins, whose depths vary from 4,000 to 7,000 m. Their bottoms are hilly, with groups and chains of underwater mountains, although abyssal plains have developed in the northeastern Pacific and at the base of the Antarctic continent. Many of the elevations are encircled by sediment fans. The largest structure of the Pacific Ocean is the East Pacific Rise, part of the worldwide system of mid-oceanic ridges. Unlike the system’s other ridges, it divides the ocean into two asymmetrical parts and lacks a clearly discernible rift valley. The rise divides into several branches—the Galápagos, Cocos, and Macquarie ridges; the Gulf of California is located at its northern extension.

Among the large elevations of the Pacific bed are volcanic seamounts and ridges: Line, Hawaiian, Emperor, Marcus-Necker, Caroline, Marshall Islands, and Tuamotu. There are also block uplifts such as the Shatsky and Manihiki rises. Many of the elevations are surmounted by volcanic mountains, guyots, or islands, the largest of which are the Hawaiian Islands with active volcanoes. The eastern Pacific Ocean and the East Pacific Rise are intersected by numerous long fracture zones extending in a sublatitudinal and northwestern direction and having large horizontal dislocations, among them the Mendocino, Murray, Molokai, Clarion, Clipperton, and Galápagos and Easter Island and Eltanin Island fracture zones. Their relief is dominated by escarpments and mountain chains.

The distribution of bottom sediments is closely linked with the tectonics and topography of the ocean floor and is subject to cir-cumcontinental, vertical, and climatic zonality. Terrigenous de-trital (sands and silts) and clayey deposits have developed along the underwater edges of the continents, in the sea basins, and in the deep-sea trenches and adjacent parts of the ocean bed. An important role is played by turbidites and, in the higher latitudes, by detrital material of glacial dispersion.

The most prevalent biogenic sediments are pelagic calcareous (coccolith-foraminifer) oozes, which occupy extensive areas of the bottom at depths of 4–4.5 km. In shallower areas the main calcareous sediments are shell and coral-algae deposits. Siliceous sediments, both diatom and diatom-radiolarian, form three latitudinal belts in zones of high phytoplankton productivity—a northern belt, which encompasses the Far Eastern seas, an equatorial belt, and a sub-Antarctic belt. Diatoma ooze also occurs in the Gulf of California, near the coast of Peru, and on the bottom of some trenches and depressions.

Pelagic red clays have developed at depths greater than 4.5–5 km in areas of lesser productivity. In the western Pacific bottom sediments are frequently enriched with products of andesite vol-canism (ash and tuffites) and in the central Pacific by those of basaltic volcanism. Vast areas of the bottom are covered with ferro-manganese nodules rich in Cu, Ni, and Co. In the vicinity of the East Pacific Rise and in adjacent parts of the basins there are metal-bearing silts containing more than 10 percent Fe. Phosphorites, generally pre-Anthropogene, are found on shelfs and underwater mountains. Recent phosphorites are encountered on the Peru and Chile shelfs. Outcrops of ancient sediments, dating from the Neogene to the Late Cretaceous, as well as outcrops of volcanic rock, chiefly basalt, are abundant on the summits and slopes of many ridges and rises, in fracture zones, and on the hilly bottoms of basins. Intrusive ultrabasic and basic rocks—dunites, peridotites, serpentinites, and gabbronorites—have been discovered in the Tonga and Marianas trenches.

The thickness of the sedimentary layer on the ocean floor and in the trenches ranges from 0 to 2–3 km (with an average layer of a few hundred meters), increasing near the continents and in the equatorial zone. Data gathered from deep-sea boring reveal that the age of the base of the sediment layer and of the cover of basalts gradually changes as one moves northwestward from the East Pacific from Pleistocene-Pliocene to Jurassic (Shatsky Rise). Southeastward from the East Pacific Rise, the sediments gradually become Cretaceous. The cross sections of many borings have established the replacement (downward) of deep-sea sediments by more shallow ones, major stratigraphic discontinuities, and changes in paleogeographic conditions during the Cenozoic and Mesozoic.

Below the sediment layer in the oceanic crust there is a “second” and a “third” layer. The second layer consists chiefly of basalts and possibly, in places, of metamorphosed sedimentary rocks. Seismic waves pass through this layer at a rate of approximately 5 km/sec. The third layer is probably composed of metabasalts, gabbros, amphibolites, and serpentinites and has a seismic-wave velocity of 6.6–6.9 km/sec. The velocities in the upper part of the mantle exceed 8 km/sec; on the East Pacific Rise they are 7.3–7.7 km/sec. The Pacific Ocean is characterized by a complex system of linear magnetic anomalies, which provide a record of the development of the earth’s crust. Although its floor is young, the Pacific is the world’s oldest ocean. (SeeOCEAN for hypotheses concerning the origin of the Pacific.)

Minerals. Exploration for petroleum and natural gas is being conducted on many shelfs of the Pacific Ocean. Petroleum deposits are being worked off California, in Alaska’s Cook Inlet, and in the Japan, South China, Java, and Tasman seas. On the ocean floor the most promising deposits of ferromanganese nodules lie at depths of 3.5–5.5 km.

Many countries bordering on the Pacific Basin are prospecting for or extracting valuable minerals from coastal placers, among them zircon (zirconium silicate), rutile, ilmenite, monazite, titanomagnetite, and cassiterite. Deposits of these minerals have been discovered off Australia, the USA, Japan, Indonesia, Malaysia, and Thailand.

P. L. BEZRUKOV

Climate. The great extent of the Pacific Ocean from north to south determines the diversity of its climates, which vary from equatorial to subarctic in the north and to antarctic in the south. The greater part of the ocean’s surface, the area lying approximately between 40° N lat. and 42° S lat., is situated in the equatorial, tropical, and subtropical climatic zones. The atmospheric circulation over the Pacific is determined by four principal pressure areas: the Aleutian low and the North Pacific, South Pacific, and Antarctic highs. The interaction between these centers of atmospheric activity accounts for the remarkable steadiness of the trade winds (moderate winds blowing from the northeast in the north and southeast in the south) in the tropical and subtropical parts of the Pacific and of the strong westerlies in the temperate latitudes. Particularly strong winds are observed in the southern temperate latitudes, where the storm frequency reaches 25–35 percent. In the northern temperate latitudes the storm frequency is 30 percent in winter and 5 percent in summer. In the west typhoons often occur in the tropical zones from June through November. The northwestern Pacific is marked by monsoon atmospheric circulation.

The average February air temperature declines from 26°–27°C at the equator to – 20°C in the Bering Strait and – 10°C off Antarctica. The average August temperature, 26°–28°C at the equator, drops to 6°–8°C in the Bering Strait and to – 25°C near Antarctica. North of 40° S lat. there are substantial differences in air temperature between the eastern and western parts of the ocean, owing to the preponderant influence of warm or cold currents and to the nature of the winds. In the tropical and subtropical latitudes the air temperature is 4°–8°C lower in the east than in the west. In the northern temperate latitudes the opposite is true: the temperature in the east is 8°–12°C higher than in the west.

The annual frequency of cloudiness in areas of low atmospheric pressure averages 60–90 percent; in regions of high atmospheric pressure it fluctuates between 10 percent and 30 percent. The average annual precipitation exceeds 3,000 mm at the equator. In the temperate latitudes it ranges from 1,000 mm in the west to 2,000–3,000 mm in the east. The eastern edge of subtropical regions with a high atmospheric pressure receives the least amount of precipitation (100–200 mm); in the west the precipitation increases to 1,500–2,000 mm. Fogs, characteristic of the temperate latitudes, are especially frequent in the vicinity of the Kuril Islands.

Hydrology. Under the influence of the atmospheric circulation over the Pacific, the currents form anticyclonic gyres in the subtropical and tropical latitudes and cyclonic gyres in the northern temperate and southern high latitudes. In the northern Pacific the circulation is formed by the warm North Equatorial, Kuroshio, and North Pacific currents and the cold California Current. In the northern temperate latitudes, the cold Kuril Current predominates in the west and the warm Alaska Current in the east. In the southern Pacific an anticyclonic gyre is formed by the warm South Equatorial and East Australian currents, the zonal South Pacific Current, and the cold Peru Current. North of the equator, between 2°–4° and 8°–12° N lat., the northern and southern circulations are divided by the Equatorial Countercurrent.

The average temperature of the Pacific Ocean’s surface waters, 19.37° C, is two degrees higher than that of the Atlantic and Indian Ocean waters because of the relatively large expanse located in well-warmed latitudes (more than 20 kcal/cm²/year) and because of limited contact with the Arctic Ocean. The February water temperature averages 26°–28° C at the equator and -0.5° to -1°C north of 58° N lat., near the Kuril Islands, and south of 67° S lat. In August the temperature is 25°–29° C at the equator, 5°–8° C in the Bering Strait, and – 0.5° to -1° C south of 60°–62° S lat. Between 40° S lat. and 40° N lat. the water temperature in the eastern Pacific is 3°–5° C lower than in the western part. North of 40° N lat. the opposite holds true: the temperature is 4°–7° C higher in the east than in the west. South of 40° S lat., where a zonal transfer of surface waters prevails, there is no difference between the water temperature in the east and west.

In the Pacific, precipitation exceeds evaporation. Including river discharge, the ocean receives more than 30,000 cu km of fresh water annually. Consequently, its surface waters, with an average salinity of 34.58‰, are less saline than those of the other oceans. The lowest salinity (30.0–31.0‰ or less) occurs in the western and eastern parts of the northern temperate latitudes and in the coastal waters of the eastern Pacific. The highest salinity is found in the northern and southern subtropical latitudes (35.5‰ and 36.5‰, respectively). The salinity decreases from 34.5‰ or less at the equator to 32.0‰ or less in the northern high latitudes and to 33.5‰ or less in the south.

The water density on the ocean surface increases steadily from the equator to the high latitudes in conformity with the general temperature regime and distribution of salinity. It is 1.0215–1.0225 g per cu cm at the equator, 1.0265 g per cu cm or more in the north, and 1.0275 g per cu cm or more in the south. In the subtropical and tropical latitudes the water is dark blue, and its transparency in some places exceeds 50 m. In the northern temperate latitudes the open sea is generally a dark azure color, and the coastal waters are greenish. Here, the transparency decreases to 15–25 m. In the antarctic latitudes the water is greenish, with a transparency of up to 25 m.

In the northern Pacific tides are either mixed, reaching 5.4 m in the Gulf of Alaska, or semidiurnal, rising to 12.9 m in Penzhina Bay of the Sea of Okhotsk. At the Solomon Islands and along part of the coast of New Guinea, tides are diurnal and rise to 2.5 m. The strongest wind turbulence is noted between 40° and 60° S lat., an area dominated by stormy westerly winds (“roaring forties”); in the northern hemisphere, the strongest turbulence occurs north of 40° N lat. Wind-driven waves reach a height of 15 m or more and lengths exceeding 300 m. The waves known as tsunami occur most frequently in the northern, southwestern, and southeastern Pacific.

In the northern Pacific, ice forms in seas with harsh winter climatic conditions (Bering Sea, Sea of Okhotsk, Sea of Japan, and Yellow Sea) and in the bays along the island of Hokkaido and the Kamchatka and Alaska peninsulas. During the winter and spring the Kuril Current carries ice floes to the extreme northwestern part of the Pacific Ocean. Small icebergs are encountered in the Gulf of Alaska. In the southern Pacific ice floes and icebergs are formed off the coast of Antarctica and carried by currents and winds into the open ocean. The northernmost boundary of floating ice extends along 61°–64° S lat. in winter and along 70° S lat. in summer. At the end of the summer, icebergs, most of them formed in the Ross Sea, are carried to 46°–48° S lat.

The Pacific’s intermediate and abyssal circulations and its vertical structure are formed by waters that sink in zones of convergence of surface currents and by abyssal waters flowing from the Indian and Atlantic oceans. The higher the latitudes where the sinking of water occurs, the lower the level it will occupy in the ocean. The surface waters extend to 100–150 m (in the antarctic latitudes, to 200 m). The water characteristics of the entire layer are similar to those on the ocean’s surface.

Approximately between 40° N lat. and 40° S lat., beneath the surface layer, lie subsurface intermediate waters that have submerged in subtropical zones of convergence in the northern and southern Pacific. Occupying a layer that extends down to 400–500 m, these waters have temperatures of 10°–20° C and a salinity of more than 35‰. Their oxygen content ranges from 1 milliliter per liter (ml/l) to 5.8 ml/l. Below this layer, to depths of 1,000–1,500 m, are intermediate waters that have sunk at the northern and southern polar ocean fronts. Their temperatures vary between 3° and 6° C, and their salinity is 33.9–34.3‰ in the north and 34.1–34.5‰ in the south. Their oxygen content is 0.5–1.6 ml/l in the north and 2.7–4.1 ml/l in the south.

Abyssal waters occupy a layer between 1,000–1,500 m and 3,000–3,500 m. They are formed in the southern high and temperate latitudes through the mixing of Pacific waters with abyssal waters from the Atlantic and Indian oceans. The abyssal waters have temperatures of 1.7°–2.5° C, a salinity of 34.65–34.75‰, and an oxygen content of 2.0–2.9 ml/l in the north and 3.1–4.5 ml/l in the south. From 3,500 m to the ocean floor there are bottom waters formed in the high southern latitudes through the cooling and sinking of surface waters and their subsequent mixing with abyssal waters. Such bottom waters have temperatures of 0.24°–0.28° C and a salinity of 34.70–34.72‰ in the antarctic latitudes and temperatures of 1.0°–1.6° C and a salinity of 34.1–34.64‰ elsewhere. The oxygen content of the bottom waters ranges from 3.5 ml/l to 4.6 ml/l.

Subsurface and intermediate waters circulate in the same way as surface waters, but at much lower speeds. An exception is the subsurface Equatorial Countercurrent (Cromwell Current), which moves eastward in a direction opposite to the South Equatorial Current flowing above it. The countercurrent, about 300–400 km wide, crosses the entire ocean along the equator in a thin band between 25–50 m and 300 m. Abyssal waters flow north in a lower stream and south in an upper stream.

A. M. MUROMTSEV

Flora and fauna. With the exception of bacteria and the lower fungi, plant life is concentrated in the upper 200-m layer, known as the euphotic zone. Animals and bacteria inhabit all the water levels and the ocean bottom. The most abundant plant and animal life is found in the shelf zone, especially in shallow coastal waters. In the temperate zones these waters contain various types of brown algae and numerous mollusks, worms, crustaceans, echinoderms, and other organisms. In the tropical latitudes large coral reefs are found everywhere in shallow waters, and mangroves thrive along the coasts.

As one moves from the colder zones to the tropics, the number of species increases sharply, although the density of their distribution decreases. About 50 species of coastal algae— macrophytes—are known to exist in the Bering Strait, more than 200 off the Japanese Islands, and more than 800 in the waters of the Malay Archipelago. Whereas the seas of the Soviet Far East contain about 4,000 species of fauna, the waters of the Malay Archipelago have at least 40,000–50,000 species. In the cold and temperate zones of the ocean, despite the comparatively modest number of plant and animal species, the overall biomass increases substantially, owing to the great proliferation of some species. In the tropical zones individual forms do not achieve such a clearly marked dominance, although the number of species is very great.

With distance from the coast and increasing depth, plant and animal life becomes less diverse and less abundant. On the whole, Pacific fauna includes approximately 100,000 species, but only 4–5 percent are encountered at depths greater than 2,000 m. At depths of more than 5,000 m about 800 species of animals have been identified; below 6,000 m, about 500 species; below 7,000 m, about 200 species; and below 10,000 m, only about 20 species.

In the temperate zones the most abundant coastal algae (macrophytes) are the brown algae of the orders Fucales and La-minariales. In the tropical latitudes these give way to brown algae of the family Sargassaceae, green algae of the genera Caulerpa and Halimeda, and a number of red algae.

The surface of the pelagic area is characterized by a massive development of unicellular algae (phytoplankton), chiefly diatoms, peridiniums, and coccolithophores. Most important among the zooplankton are various crustaceans and their larvae, primarily copepods (at least 1,000 species) and euphausids. There is a considerable admixture of radiolarians (several hundred species), coelenterates (siphonophores, medusae, and ctenophores), fish eggs and larvae, and bottom-living invertebrates. In addition to the littoral and sublittoral zones, the ocean has a transitional zone (to 500–1,000 m), as well as bathyal, abyssal, and hadal zones (from 6,000 m to 11,000 m).

Plankton and bottom fauna serve as an abundant food supply for fish and marine mammals (nekton). The Pacific is especially rich in fish. At least 2,000 species are found in the tropical latitudes, and about 800 species are known to exist in the seas of the Soviet Far East, which also have 35 species of marine mammals. Commercially important fish include anchovies, Pacific salmon, herrings, chub mackerel (Scomber japonicus), sardines, Pacific saury (Cololabis saira), fish of the genus Sebastes, tunas, flounders, cod, and walleye pollock. The most valuable mammals are the sperm whale, several species of finback whale, northern fur seal, sea otter, walrus, and Steller’s sea lion. Among highly prized invertebrates are crabs (including the king crab), shrimps, oysters, scallops, and squids. The plant harvest includes laminaria (sea kelp), agar-yielding Ahnfeltia, Zostera, and phyllospadix.

Many representatives of Pacific fauna are endemic, among them the deep-sea cephalopod mollusk nautilus, most Pacific salmon, the Pacific saury, atka fish, the northern fur seal, Steller’s sea lion, and the sea otter.

L. A. ZENKEVICH

The history of the exploration of the Pacific Ocean may be divided into three periods: from ancient voyages to 1804, from 1804 to 1873, and from 1873 to the mid-1970’s. During the first period explorers studied the distribution of water and land in this part of the world and established the boundaries of the Pacific Ocean and its links with other oceans. This period began several centuries before the Common Era and included the age of great geographical discoveries and the Russian voyages and discoveries in the northern Pacific. Among the most famous voyages were those of F. Magellan in 1520–21, A. Tasman in 1642–43, S. I. Dezhnev in 1648, and V. Bering and A. I. Chirikov in 1728 and 1741. Also dating from this period are the voyages of the Englishman J. Cook in 1768–71, 1772–75, and 1776–79. By the early 19th century, all but the southern boundary of the Pacific Ocean had been explored.

During the second period the physical properties of the water were studied, and deep-sea investigations of the Pacific were conducted. Such studies were initiated by the first Russian round-the-world expedition, headed by I. F. Kruzenshtern and Iu. F. Lisianskii on the ships Nadezhda and Neva in 1804–06.

In the third period complex oceanographic studies were made by special expeditions and coastal stations, and oceanographic institutions and international associations were organized. The first oceanographic expedition—the voyage of the British ship Challenger (1872–76)—was followed by S. O. Makarov’s voyage on the Vitiaz’ (1886–89) and by the voyages of the Albatross (1888–1905) and Planet (1906–07). In 1920, Japan began systematic operations in the vicinity of the Kuroshio Current. On the high seas major research expeditions were conducted by the Japanese ships Manshu (1925–28), Shintoku Maru (1930–32), and Shumpu Maru (1928–30, 1933–35); by the US ships Carnegie (1928–29), Oglala (1935), and Bushnell (1937–40); and by the British ship Discovery II (1932–33).

Soviet expeditions on the Vitiaz’ (beginning in 1949), A. I. Voeikov (from 1959), Iu. M. Shokal’skii (from 1960), and Akademik Sergei Korolev (1970) initiated a broad range of geophysical studies pertaining to the hydrosphere and the upper layers of the atmosphere. Concurrently, research expeditions were conducted on the US ships Horizon (from 1946), Hugh M. Smith (from 1950), and Spencer F. Baird (from 1946); the British Challenger II (1950–52); the Swedish Albatross III (1947–48); and the Danish Galathea (1950–52).

Important research was done in conjunction with the Norpac (August 1955) and Equapac (in later years) expeditions, the programs of the International Geophysical Year (IGY) and International Geophysical Cooperation (from 1957), and the international studies of the Kuroshio Current and its adjacent regions (from 1965). In carrying out these projects, the work of a large number of expeditionary ships from various countries was coordinated and synchronized. During the IGY, a major contribution to the study of the Pacific’s underwater topography was made by US expeditions on the Spencer F. Baird, Horizon, Vema, Atka, and Glacier and by Soviet expeditions on the Vitiaz’ and the Ob’. The material gathered during the IGY has been used to compile new bathymetric and marine navigation charts of the Pacific Ocean. Also valuable are the deep-sea drilling operations conducted since 1968 by the American ship Glomar Challenger, the study of the displacement of water masses at great depths, and biological research.

A. M. MUROMTSEV

General characteristics. The Pacific basin includes the water areas and islands of the Pacific Ocean and the Pacific coastal regions of Asia, Australia, South and North America, and Antarctica. Approximately half of the world’s population lives here. Located along the Asiatic coast of the Pacific Ocean are territories belonging to the USSR, China, the People’s Democratic Republic of Korea, South Korea, Vietnam, Kampuchea (Cambodia), Thailand, and Malaysia. Fringing the continent are the islands and island groups of Japan, the Philippines, Indonesia, and Singapore. Pacific waters wash the eastern coast of Australia. In the western hemisphere the Pacific states are the USA, Canada, and Mexico in North America, the small countries of Guatemala, El Salvador, Nicaragua, Costa Rica, and Panama in Central America, and Colombia, Ecuador, Peru, and Chile in South America.

Located within Oceania are the independent countries of New Zealand, Papua New Guinea, Western Samoa, Solomon Islands, Nauru, Tonga, Juwalu, and Fiji. A number of islands are possessions: French Polynesia, New Caledonia, and the Wallis and Fu-tuna Islands (France); the Gilbert and the Pitcairn groups (Great Britain); and Guam, the Midway Islands, American Samoa, and Wake Island (USA). Norfolk Island belongs to Australia, and the Cook, Niue, and Tokelau islands are part of New Zealand. The New Hebrides are governed as an Anglo-French condominium. The Carolines, Marshalls, and Marianas are a UN trust territory under US administration, and the Hawaiian Islands are a state of the USA.

With their rich biological and mineral resources, large-scale agriculture, including tropical and subtropical farming, and various industries, the Pacific countries have great economic potential. Important sea and air routes connecting the four continents cross the Pacific. The ocean accounts for a major part of the world catch of marine fish and other sea products. The countries of the Pacific Basin are major producers of petroleum, natural gas, coal, bauxite, iron ore, manganese, chromite, copper ore, tin, complex ores, tungsten, nickel, cobalt, sulfur, rare earths, and radioactive minerals.

The Pacific countries are an important source of lumber from coniferous trees (USA, Canada, Soviet Union) and such other valuable species as ironwood, sal, and teak (Indonesia and the Philippines). Cinchona bark is also obtained from the Philippines and Indonesia. The Pacific countries account for a considerable share of the world output of coconut products, palm oil, peanuts, soybeans, sugarcane, rice, wheat, cotton, and rubber (90 percent of the world’s rubber comes from Malaysia, Indonesia, and China). Australia and New Zealand supply the world market with large quantities of meat, wool, and butter. After World War II, the growth of older industrial regions in the capitalist countries and the rise of new industrial centers in the socialist and developing countries led to an increase in the Pacific countries’ share of the world industrial output. Japan has a large industrial potential, and the important industrial region of the western USA borders on the Pacific. In the Soviet Union the Pacific coast is part of the Far East Economic Region, one of the country’s leading economic regions.

Changes in the political and economic status of the Pacific countries during the postwar years have stimulated an expansion of foreign trade and shipping, have altered the structure and direction of cargo hauls, and have led to an increase in freight shipment in the Pacific. The amount of cargo turnover of the Pacific countries has been affected to some extent by the crises that gripped the economies of the developed capitalist countries during the 1970’s.

Shipping. Pacific shipping is expanding, chiefly owing to the increased volume of cargo hauls. At the beginning of the 1970’s some 1.5 billion tons of freight were transported across the Pacific (out of the 8.5 billion tons carried on the world’s oceans), representing 16–17 percent of the world maritime cargo transport, as contrasted with 20 percent in the years before World War II.

Transoceanic routes link the continents of Asia, North and South America, and Australia. Shipping is most intensive on the sea lanes linking North America with Asia (including the transoceanic shipping routes from Europe) and on the shipping routes connecting Asia with Australia and South America (including the maritime routes from the Indian Ocean). The interoceanic routes leading to the Indian Ocean pass through the Straits of Malacca and Sunda. The Panama Canal links the Pacific and Atlantic routes, and the Bering Strait joins the Pacific and Arctic routes.

Coastal sea routes serve both for international shipping and for cabotage. Pacific shipping is conventionally divided into six zones: the central part of the ocean (chiefly the Hawaiian Islands), the coastal zone of eastern Asia with its adjacent islands (the Soviet Far East and Japan), the South China Sea and the waters of Indonesia, the maritime waters of Australia and southern Oceania, the coastal waters of Latin America and the Panama Canal, and the coastal waters of North America.

Maritime transportation is highly important for the Pacific countries, whose foreign trade turnover accounts for approximately one-third of the total turnover of international trade. However, most of these countries do not have a sufficiently large national fleet. Aside from Japan, whose fleet totaled 39.7 million tons in 1974, the USA, the USSR, the People’s Republic of China, and Indonesia, the Pacific countries either lack fleets or maintain small ones. The maritime trade of many of these countries depends on foreign shipping companies, for the most part British, American, or Japanese.

Most of the maritime cargo consists of petroleum (from the Indian Ocean Basin and Indonesia), forest products (from Indonesia, Canada, the USSR, and the USA), metallic ores (from Australia, Canada, Malaysia, Indonesia, Thailand), foodstuffs, and agricultural raw material (from the USA, Australia, Canada, Indonesia, and the islands of Oceania).

Among the Pacific countries Japan has the greatest foreign trade turnover. A major Pacific center for receiving and shipping freight, it had a total cargo turnover of 664.3 million tons in 1974, excluding coastal shipping. Of this amount, iron ore imports alone accounted for 142 million tons; coal imports, for 60 million tons; petroleum imports, for 250 million tons; and the import of petroleum products, for 26 million tons. Japan has many large ports that are also important industrial centers. The largest industrial port complex emerged during the 1960’s in Tokyo Bay. It includes Yokohama (with a cargo turnover of about 130 million tons in 1974), Kawasaki (more than 90 million tons), and Tokyo (55.5 million tons). The ports of Kobe (142 million tons), Osaka (77 million tons), and Sakai (75 million tons) form a large conurbation in Osaka Bay. Other major ports include Nagoya (88 million tons), Nagasaki, Sasebo, Kitakyushu, Chiba (123 million tons), and Hakodate (35 million tons). The ports on the western coast have expanded through the growth of Soviet-Japanese trade. Near the port of Niigata a special port has been built to receive cargoes from the Soviet Union. Several ports on the To-yama and Wakasa bays have been modernized, among them Maizuru and the port serving the Kanazawa. Some of the ports have been equipped with special wharves for container ships.

The People’s Democratic Republic of Korea has increased its maritime shipping and enlarged several of its ports: Hungnam, which has merged with the industrial center of Hamhung; Nam-po, the outport of Pyongyang; and Chongjin and Wonsan. In South Korea the major ports are Pusan on the Korea Strait (with a cargo turnover of 14 million tons), Inchon (11.6 million tons), and Ulsan (13.8 million tons in 1974). China’s maritime shipping has increased in volume. Such ports as Tientsin and Dairen have been modernized to accommodate the increase in petroleum exports. China’s principal ports, Shanghai and Canton, have been enlarged. In Vietnam the largest ports are Haiphong and Ho Chi Minh City, formerly Saigon.

In Malaysia, where the main ports are Sandakan, Miri, and Klang, the total cargo turnover exceeded 35 million tons in 1974. Indonesia’s ports handled more than 100 million tons of cargo in 1974. Most of the cargo passed through the ports of Dumai (more than 50 million tons, petroleum), Jakarta-Tandjungpriok (8.5 million tons), Palembang (9.2 million tons), and Surabaya (3.7 million tons). The total cargo turnover of the Philippine ports exceeds 30 million tons; the principal ports are Manila (with Bataan, petroleum) and Batangas. Two ports in Southeast Asia involved in large-scale international trade are Hong Kong, with a cargo turnover of 18.6 million tons, and Singapore, which handles more than 60 million tons (1974).

Between 1960 and 1974, Australia’s ports doubled their cargo turnover (from 87 million tons to 180 million tons) owing to an increase in the country’s output and export of mineral raw materials. The older ports are Sydney (14.9 million tons in 1974), Melbourne (14.4 million tons), Newcastle (16.2 million tons), Port Kembla (13.6 million tons), Brisbane (8.9 million tons), and Darwin. Two new ports have expanded during the 1960’s: Port Hedland (26 million tons in 1974, as contrasted with 200,000 tons in 1960) and Dampier (23 million tons), both of them located on the Indian Ocean. New Zealand’s ports handled more than 32 million tons of sea freight in 1973. The most important ports are Auckland (about 6 million tons), Wanganui (7.7 million tons), and Wellington (5.6 million tons).

Canada’s Pacific ports account for about one-fifth of its maritime cargo turnover of more than 170 million tons. The leading port on the Pacific is Vancouver, with a cargo turnover of 33.3 million tons (1974). Since World War II, major economic changes have occurred in the western USA, where economic expansion has proceeded at a more rapid pace than elsewhere in the country and where various modern industries have been established, among them the production of atomic energy and missiles. These developments assured the Pacific ports of about one-fifth of the cargo turnover of the US ports, which totaled about 700 million tons in 1974, excluding coastal shipping. Among the largest ports on the Pacific are Los Angeles and Long Beach (about 47 million tons), San Francisco-Oakland (about 36 million tons), Seattle (12.5 million tons), Portland (17 million tons), and Honolulu in the Hawaiian Islands (9.5 million tons).

The maritime transport of South America’s Pacific countries is much less than that of North America. The largest ports are Huasco (5.5 million tons) and Valparaiso (3.5 million tons) in Chile, Callao (more than 3 million tons) and San Nicolás (9.4 million tons) in Peru, Buenaventura (1.8 million tons) in Colombia, and Salinas, Guayaquil, and Esmeraldas in Ecuador.

The USSR trades with almost all the countries of the Pacific Basin via the Pacific maritime routes. The European USSR is connected with the Soviet Far East by maritime routes crossing the Pacific seas (Bering Sea, Sea of Okhotsk, Sea of Japan) and the waters of the Soviet arctic (Northern Sea Route). The Soviet Union’s major Pacific ports are Vladivostok, Nakhodka, Vanino, Nagaevo, Petropavlovsk-Kamchatskii, Korsakov, and Aleksan-drovsk-Sakhalinskii. The rapid development of the USSR’s eastern regions and the expansion of the country’s foreign trade have prompted the construction of the port of Vostochnyi in Vrangel’ Bay, near Nakhodka.

Air transportation. Passenger traffic across the Pacific is handled chiefly by air services linking East and Southeast Asia, North and South America, Australia, New Zealand, and Oceania. Most of the air routes cross the northern and central Pacific, and the Hawaiian Islands are an important transit point for transoceanic flights. In 1936 regular flights were introduced from San Francisco (USA) to Honolulu (Hawaiian Islands) and Manila (Philippines). Subsequently, the route was extended to Hong Kong. In 1940 scheduled flights were begun from Honolulu to Auckland (New Zealand). Transpacific air routes became links in the long-distance routes connecting North American and Western European cities with South Asia and the Near East.

The major airlines in the USA, Great Britain, France, the Netherlands, Japan, India, and the Scandinavian countries run flights over the Pacific. Japan began the first regular international flights from Tokyo to San Francisco in 1954 and from Tokyo to New York via Alaska in 1969. A new stage was reached with the inauguration of flights over the Soviet Union. The Pacific countries were brought considerably closer to Europe in 1967, when a joint Soviet-Japanese air route was established from Tokyo to Moscow. In 1970 it was extended to Paris and London, becoming the shortest route from Japan to Europe (approximately 13 flying hours).

Along with the growth of long-distance air transportation, domestic flights became increasingly important in the Pacific countries. National airlines were organized in the People’s Republic of China, Australia, New Zealand, the Philippines, Thailand, Indonesia, and other countries. The most important passenger services over the Pacific are provided by the Japanese, American, Australian, and New Zealand airlines. The longest Pacific air routes link San Francisco with Singapore and San Francisco with Sydney (more than 12,000 km). The shortest transoceanic route is the one from Vancouver to Tokyo (more than 7,500 km). The most heavily traveled routes are those from Vancouver, Seattle, San Francisco, and Los Angeles (via Honolulu) to Tokyo (and further on to Seoul, Taipei, and Hong Kong), to Manila (and on to Bangkok, Singapore, and Darwin), and to Suva (and on to Sydney, Auckland, and Wellington).

Communication. Because of the Pacific’s vast extent the various means of communication are highly important both within and between the Pacific countries.

Initially, attention focused on the laying of underwater cables across the Pacific that would connect the western USA with Japan and China. The Challenger expedition (1872–76) made the first study of the feasibility of laying a cable across the Pacific Ocean. The first underwater telegraph cable, extending for 12,550 km along the bottom of the Pacific, was laid in 1902 by Great Britain. Passing through Fanning Island and Fiji, it connected Canada with New Zealand and Australia. In 1905 the USA laid a 14,100-km cable on the Pacific floor from San Francisco to the Philippines via the Hawaiian Islands, the Midway Islands, and Guam; from Guam branches were laid to Japan, Indonesia, and China.

The first Pacific underwater telephone cable linked San Francisco with Honolulu (USA) in 1957; a second cable was laid between the two cities in 1964. In 1964 an underwater telephone-telegraph cable, 9,900 km long, went into operation, linking Japan with the USA via the Hawaiian Islands. In 1969 the 890-km Far East cable was laid across the Sea of Japan. Radio communication has been widely used for a long time. Earth satellites, now being used for communication across the Pacific, have considerably expanded the range of communications channels among the countries of the Pacific Basin.

Fisheries. The fish catch of the Pacific exceeds that taken from any other ocean. According to UN data, 33.5 million tons of fish were harvested in the Pacific in 1971, almost half of the world fish catch of 69.4 million tons. Fish from the tropical and the temperate latitudes have the greatest commercial value. Among these are Pacific salmon, herrings, cod, Sebastes, and flounders. Large quantities of invertebrates—mollusks and crustaceans (crabs)— are also caught. Whaling is carried on in the peripheral waters of the polar latitudes. Limited numbers of such marine mammals as walruses and fur and other seals are hunted. A number of valuable marine algae, such as sea kale, are gathered for use in the food-processing industry and in medicine. The most productive commercial fishing grounds are in the northwestern and west-central Pacific (see Table 1).

Table 1. Fish catch in the various parts of the Pacific Ocean (million tons)
Regions	1965	1970	1971	1973
Northwestern ..............	10.7	13.0	14.6	16.4
Northeastern ..............	1.5	2.6	2.0	1.9
West-Central ..............	2.5	3.8	4.0	5.0
East-Central ..............	0.6	0.9	0.9	1.2
Southwestern ..............	0.2	0.2	0.2	0.3
Southeastern ..............	8.3	3.7	11.7	2.9
Antarctic ..............	—	—	—	—
Total ..............	24.0	34.3	33.5	27.7

The Japanese, whose fishing operations are largely restricted to the Pacific, account for the largest catch, more than 10 million tons annually. Japan’s main fishing bases are Tokyo, Nagasaki, and Shimonoseki. China also has large catches; its principal fishing bases are the Choushan Islands, Yentai (Chefoo), Tsing-tao, and Dairen. More than a million tons are caught annually by Thailand (1.8 million tons), Indonesia (1.3 million tons), the Philippines (1.1 million tons), Vietnam, South Korea, and the People’s Democratic Republic of Korea. One of the most important regions for obtaining fish and marine products is the Soviet Far East. Australia, New Zealand, and Oceania account for 250,000 tons. Along the Pacific coast of North and South America the leading fishing nations are Peru (about 5 million tons per year), Chile (about 1 million tons), and the USA (500,000 tons).

Several international conventions on fishing have been adopted for the Pacific Basin to assure the rational and effective utilization of the ocean’s natural resources, based on the scientific regulation of fishing.

Mineral resources. During the 1960’s and 1970’s there has been a reevaluation of the mineral resources occurring on or beneath the ocean floor and in the waters of the Pacific. Deposits of petroleum and natural gas have been discovered and are being exploited, primarily in the shelf zone. By the early 1970’s, about one-fifth of the world petroleum output came from shelf areas, and the Pacific shelf accounted for approximately one-tenth of the amount extracted from the shelf of the world ocean. Offshore oil deposits are being worked by Indonesia (Java Sea), Malaysia, and Japan in Asia; the USA (Alaska, California) in the Americas; and Australia and New Zealand in Oceania. The leading producers of oil from oceanic areas are the USA (more than 25 million tons), Australia (about 15 million tons), and Malaysia (more than 10 million tons). China has begun operating oil rigs in the shallower parts of the Yellow Sea. Japan has expanded its extraction of petroleum and natural gas on the shelf.

Solid minerals are being extracted from subsea-floor rocks by Japan, Australia, Chile, and Taiwan. Japan is giving special attention to the problem of extracting ferromanganese nodules from the ocean floor. Among minerals being extracted from coastal placers are ilmenite, rutile, zircon, and monazite (Australia, Japan, and New Zealand), as well as cassiterite (Indonesia, Malaysia, and Thailand). In the USSR coastal placers of titanomagnetite are known to exist off the Kuril Islands and Sakhalin. Salt is extracted from seawater; the largest such industry is at Ch’anglu in China.

K. M. POPOV

From remote antiquity the inhabitants of the Pacific islands maintained maritime ties with the population of the coastal countries. China, one of the great powers along the Pacific coast, pursued a policy of active southward expansion from the third century B.C., launching numerous predatory campaigns against Annam and Tonkin, against Japan during the reign of the Yuan Dynasty in the 13th and 14th centuries A.D., and against Burma, Vietnam, and Korea in the 17th and 18th centuries.

During the 16th century European ships appeared in the Pacific. The firstcomers, Portuguese and Spanish navigators, were followed in the late 16th and early 17th centuries by Dutch, British, and other European explorers. In the 16th century the Spaniards captured and occupied the Pacific coast of Central and South America. During the second half of the 16th century Europeans began seizing territory in the Asian part of the Pacific Ocean: the Spaniards claimed part of the Philippines and several other islands; the Portuguese took Macao in China; and the Dutch began their conquest of Indonesia in the 17th century. In the 1630’s Russian explorers and navigators reached the Pacific coast. Soon after the discovery of the Kuril and Aleutian islands and Alaska (in the 18th century), Russians began moving into these areas. In the second half of the 18th century Great Britain intensified its activity in the Pacific Basin. During the Seven Years’ War (1756–63) Britain strengthened its hold on India and the approaches to the Pacific and took possession of Canada, which became one of the staging areas for securing the Pacific Northwest. Other British annexations followed: Australia (from 1788), Singapore (1819–24), New Zealand (1840), and various major islands. In 1842, Britain took the island of Hong Kong from China.

The importance of the Pacific Ocean in world trade increased markedly during the 19th century as sailing vessels gave way to steamships and the discovery of gold in California and Australia led to the rapid settlement of these regions. By the mid-19th century the Pacific was crossed by numerous trade routes. The efforts of the major capitalist powers to establish outposts and acquire markets and sources of raw materials in the Pacific Basin were accompanied by the enslavement of the indigenous peoples. Supported by the USA during the second half of the 19th century, Great Britain and France unleashed a number of aggressive wars against China, with which unequal treaties were concluded. In 1854 the USA imposed the first onerous treaty on Japan. France seized New Caledonia in 1853 and Indochina between 1857 and 1885. In the 19th century Great Britain completed its conquest of Malaya, begun in the late 18th century, gained control of Burma in the 1880’s, and seized the entire northern coast of Kalimantan (1881–89), southeastern New Guinea (Irian, 1884), and the Gilbert Islands (1892). In 1867 the USA purchased Alaska and the Aleutian Islands from Russia. In 1884 Germany occupied northeastern New Guinea, whose western part had been claimed by the Netherlands as early as the 1820’s.

In 1875 the Japanese government persuaded Russia to relinquish to Japan the Kuril Islands, which had been discovered by Russians and which rightfully belonged to Russia. In 1876 Japan imposed an onerous treaty on Korea, and during the Sino-Japanese War of 1894–95 it captured Taiwan and the Penghu Islands (Pescadores). Along with Japan, the other major powers also played an active part in dividing China into spheres of influence during the 1890’s. In 1897, Germany seized Kiaochow Bay and the adjacent part of Shantung Province. The next year Great Britain “leased” the port of Weihaiwei, and France acquired Kwangchow Bay. Meanwhile, Russia proceeded to establish a base at Port Arthur (Lüshun), allegedly leased Kwantung.

As capitalism entered the stage of imperialism, the USA embarked on a forcible repartition of the Pacific possessions. In 1898 it declared war on Spain, seizing the Philippines and Guam, and annexed the Hawaiian Islands. The next year it proclaimed the open door policy, intended to turn China into an American sphere of influence. Germany compelled Spain to sell it the Carolines and Marshalls in 1899 and the Palau Islands in 1902 and concluded an agreement with the USA and Great Britain concerning the partition of Samoa. During the Russo-Japanese War of 1904–05, Japan seized southern Sakhalin and Kwantung and established a Japanese protectorate over Korea, later annexing the country (1910).

At the outbreak of World War I, Japan intensified its expansion in China, occupying Shantung in 1914 and presenting its Twenty-one Demands in 1915. It also took possession of German-held islands lying north of the equator. The opening of the Panama Canal in 1914 gave impetus to American expansion in the Pacific Basin. The exacerbation of imperialist conflicts in the Pacific Basin was reflected in the drawing up of the Versailles Peace Treaty of 1919 and especially in the Washington Conference of 1921–22.

The upswing in the national liberation movement that occurred under the influence of the Great October Socialist Revolution in Russia posed a threat to the imperialist domination of conquered territory. In China, which remained the focus of imperialist conflicts, as well as in the entire Pacific Basin, the position of the imperialist powers was seriously undermined by the nationalist revolution of 1925–27. Japan sought to take advantage of the weakened position of the Western countries in China. With the tacit approval of the Western powers, who calculated on directing Japanese aggression against the USSR, Japan seized Northeast China in 1931. In 1937, Japan began a war to conquer all of China, and within a short time it occupied the country’s coastal regions. The USSR rendered diplomatic, economic, and military assistance to the Chinese people in their struggle against Japanese aggression.

After the outbreak of World War II, Japan occupied French Indochina. In attacking the American military base at Pearl Harbor on Dec. 7,1941, Japan openly entered the war on the side of fascist Germany, occupying Thailand, Malaya, the Philippines, Indonesia, Burma, and other areas during 1941–42. At the end of 1942 the strategic initiative in the Pacific war began to shift to the USA and Great Britain. However, the armed forces of the USSR, which declared war on Japan on Aug. 8, 1945, played a decisive role in the defeat of the Japanese militarists.

After Japan’s surrender on Sept. 2, 1945, southern Sakhalin and the Kuril Islands were returned to the Soviet Union in accordance with the agreements providing for a postwar settlement. The national liberation movement in the Pacific Basin gained momentum. The Republic of Indonesia was proclaimed in August 1945; the Democratic Republic of Vietnam, in September 1945; and the Union of Burma, in January 1948. The People’s Democratic Republic of Korea was formed in September 1948, and the People’s Republic of China was proclaimed on Oct. 1, 1949. Liberation movements arose in Laos, Cambodia, the Philippines (where independence was proclaimed in July 1946), Malaya, and elsewhere. On the whole, imperialism’s position in the Pacific was seriously undermined.

Under these circumstances the USA occupied a number of Pacific islands that had belonged to Japan, forced out Great Britain, and created three lines of staging areas and bases in the Pacific: an inner, an intermediate, and an outer line. The inner line of strategic defense included the military bases at San Diego, Long Beach, San Francisco, and elsewhere on the Pacific coast. The intermediate line was formed by bases on the Hawaiian, Marshall, Caroline, Mariana, and Aleutian islands, as well as on Wake Island, the Midway Islands, and Guam. The outer line comprised bases in Japan, South Korea, Taiwan, the Philippines, Australia, and New Zealand. Pearl Harbor is the main base of the USA’s Pacific Fleet, which includes more than 400 combat ships and auxiliary craft as well as 3,000 airplanes. Other capitalist countries also maintain naval bases in the Pacific, among them Japan, Indonesia, Thailand, the Philippines, Australia, Peru, and Chile. The Pacific has served as a site for nuclear weapons tests. The USA has conducted such tests near the atoll of Bikini, on the Aleutian Islands, and near Christmas Island; Great Britain, near Christmas Island; and France, near Mururoa Atoll in French Polynesia.

On the initiative of the USA, several military and political groupings were formed in the Pacific Basin: ANZUS, SEATO (in September 1975 its ministerial council adopted a resolution to dissolve the organization), and the Asian and Pacific Council. In 1951 the USA and Japan signed the Treaty of San Francisco and the Security Treaty. After stationing troops on Taiwan in 1950, the USA concluded a “treaty of alliance” with the Kuomintang regime on the island (1954). The USA’s interference, under the UN flag, in the civil war in Korea in 1950 ended in failure three years later. However, the USA continues to maintain troops in South Korea.

Between the 1950’s and the 1970’s the liberation movement in the Pacific Basin won new victories in its struggle against imperialism. The people of Indonesia gained their independence, and in 1962 Indonesia succeeded in liberating West Irian, which came under Indonesian administration in 1963 and was renamed Irian Jaya in 1973. The peoples of Malaya freed themselves from colonial oppression, and the independent Federation of Malaysia was proclaimed in 1963 (Singapore seceded from the federation two years later). Through its struggle against the French colonialists, the Democratic Republic of Vietnam consolidated its independence.

Begun in 1964–65, the American aggression in Vietnam ended in a crushing defeat for American imperialism. Military operations in Vietnam were brought to an end by the Paris Agreement, concluded in January 1973, but in March 1975, after repeated violations of the agreement by the Saigon puppet government, hostilities were resumed. During subsequent battles the armed forces of Saigon were routed, and all of South Vietnam was liberated, thus paving the way for the unification of Vietnam as a single socialist state, called the Socialist Republic of Vietnam since July 1976. The liberation of Cambodia was completed in April 1975, and in January 1976 the country was renamed Democratic Kampuchea. The reactionary forces also suffered defeat in Laos, which in December 1975 was proclaimed the Lao People’s Democratic Republic. During the 1960’s and 1970’s many colonial countries in Oceania achieved their independence.

M. S. KAPITSA

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Pacific Ocean

[pə′sif·ik ′ō·shən] (geography) The largest division of the hydrosphere, having an area of 63,690 square miles (165,000,000 square kilometers) and covering 46% of the surface of the total extent of the oceans and seas; it is bounded by Asia and Australia on the west and North and South America on the east.

Pacific Ocean

Its American coast discovered by Vasco Nuñez de Balboa in 1513. [Amer. Hist.: NCE, 213]See: Discovery

Pacific Ocean

the world's largest and deepest ocean, lying between Asia and Australia and North and South America: almost landlocked in the north, linked with the Arctic Ocean only by the Bering Strait, and extending to Antarctica in the south; has exceptionally deep trenches, and a large number of volcanic and coral islands. Area: about 165 760 000 sq. km (64 000 000 sq. miles). Average depth: 4215 m (14 050 ft.). Greatest depth: Challenger Deep (in the Marianas Trench), 11 033 m (37 073 ft.). Greatest width: (between Panama and Mindanao, Philippines) 17 066 km (10 600 miles)

Pacific Ocean

Pacific Ocean

Pacific Ocean

Pacif′ic O′cean

Pacific Ocean

Pacific Ocean

Pacific Ocean,

Physical Geography

Extent and Seas

Coastline and Islands

Ocean Floor

Currents

Commerce and Shipping

Exploration and Settlement

Bibliography

Pacific Ocean

REFERENCES

Pacific Ocean

Pacific Ocean

Pacific Ocean

Pacific Ocean

Synonyms for Pacific Ocean

noun the largest ocean in the world

Synonyms

Related Words