Within the Pacific Ocean, all natural zones are distinguished, except for the North Polar (Arctic).
Northern subpolar ( subarctic) the belt occupies most of the Bering and Okhotsk seas. In the Pacific Ocean, the northern subpolar belt has some features. It is not directly affected by the waters of the Arctic basin; penetrate and powerful jets of warm, highly saline waters. It is dominated by cold waters. Within the belt there are extensive shelves. On the shallow shelf, nutrients are not lost irretrievably at great depths, but are included in the cycle of organic matter, so shelf waters are characterized by high biological and commercial productivity.
The northern temperate zone is a vast ocean area stretching from Asia to North America. Here interact cold and warm air masses, westerly winds dominate. In the north of the belt there is the Aleutian minimum of atmospheric pressure, well expressed in winter, in the south there is the northern part of the Hawaiian maximum. The northern temperate zone includes the Sea of Japan and the Yellow Sea.
The northern subtropical zone is represented by a relatively narrow strip approximately between 23 and 35° N. sh., stretching from Asia to North America. The belt is characterized by weak and changeable air and ocean currents, high atmospheric pressure, and the formation of sea tropical air, clear skies, high evaporation and water salinity up to 35.5%. The East China Sea is located in the belt.
The northern tropical belt stretches from the coasts of Mexico and Central America to the Philippine Islands and Taiwan, and continues to the coasts of Vietnam and Thailand in the South China Sea. A significant part of the belt is dominated by the Northern Trade Winds and the Northern Trade Wind Current. The monsoon circulation is developed in the western part. The belt is characterized by high water temperatures and salinity, and low bioproductivity.
The equatorial belt occupies a vast and complex area of water in the Pacific Ocean. The bottom topography and geological structure are most complex in the west and relatively simple in the east. This is the area of attenuation of the trade winds of both hemispheres. The belt is characterized by constant warm surface layer water, complex horizontal and vertical water circulation, large amounts of precipitation, vortex movements, relatively high bioproductivity.
The southern tropical belt is represented by a vast expanse of water between Australia and Peru, including the Coral Sea. The eastern part of the belt has a relatively simple bottom topography. In the western and middle parts there are several thousand large and small islands. Hydrological conditions are determined by the Southern Trade Wind Current. The salinity of the water is lower than in the northern tropical zone, especially in summer due to heavy rainfall. The western part of the belt is influenced monsoon circulation. Tropical hurricanes are common here. They often originate between the islands of Samoa and Fiji and move west to the shores of Australia.
The southern subtropical belt stretches in a winding strip of variable width from South-Eastern Australia and to the east, covering a large Part Tasman Sea, region of New Zealand, area between 30 and 40° south. sh., closer to the coast of South America, descends to slightly lower latitudes and approaches the coast between 20 and 35 ° S. w. The deviation of the boundaries from the latitudinal strike is associated with the circulation of surface waters and the atmosphere. Belt axis in open parts The ocean serves as a subtropical convergence zone, where the waters of the South Trade Wind Current and the northern jet of the Antarctic Circumpolar Current converge. The position of the convergence zone is unstable, depending on the season And varies from year to year, but the main processes, typical for the belt, are constant: lowering of air masses, formation of an area of high pressure and sea tropical air, salinization of waters. On the eastern edge of the belt along the coast of Chile, the coastal Peruvian Current can be traced from south to north, where intense flow and rise of water occurs, resulting in the formation of a subtropical upwelling zone and the creation of large biomass.
The temperate zone includes the large northern part of the Antarctic Circumpolar Current. The northern boundary of the belt is close to 40-45° S. sh., and the southern one passes about 61-63° S. sh., i.e. along the northern border of the distribution of sea ice V September Southern temperate zone - an area dominated by westerly, north-west and south-west winds, stormy weather, significant cloudiness, low winter and summer surface water temperatures and intense transport on east of surface water masses.
General information and physical-geographical location
The Pacific (Great) Ocean is located in all hemispheres. Lands between continents. Eurasia and. Australia in the west. North and South. America in the east and Antarctica in the south
The Pacific Ocean occupies more than 1/3 of the planet's surface and almost half. World ocean. The coastline is relatively straight offshore. Northern and. South. America and is severely dismembered off the coast. Eurasia. Into the composition. The Pacific Ocean includes a number of marginal seas. Eastern and. South-Eastern. Asia's oceans are home to a large number of archipelagos and individual islands.
Bottom relief
The Pacific Ocean has a very complex bottom topography. The shelf occupies a small area. Off the coast. Northern and. South. America, its width does not exceed tens of kilometers, but off the coast. In Eurasia it is measured in hundreds of kilometers. In the peripheral parts of the ocean there are deep-sea trenches. Most of the deep-sea trenches are located in the Pacific Ocean. The World Ocean (25 x 35, having a depth of more than 5 km) and all four trenches are more than 10 km deep. Among the latter. The Mariana Trench with its deepest bottom mark. World ocean - 11022 m. Large uplifts, individual mountains and ridges divide the ocean floor into ridges. Located in the southeast. The Pacific Rise, part of the system of mid-ocean ridges.
Most of the ocean lies on. Pacific lithospheric plate, which interacts with neighboring
slabs. It is with interaction zones that deep-sea trenches and island arcs are associated
An almost continuous chain of active volcanoes is associated with the system of deep-sea trenches and mountain structures on the continents and islands surrounding the ocean. Pacific "Ring of Fire" In this zone, land and underwater earthquakes are frequent, causing tsunami waves.
Climate
The Pacific Ocean is located in almost all climate zones. Most of it lies in the equatorial, subequatorial and tropical zones. The air temperature over these waters throughout the year in Tana is 16 ° 24 °. C. In the north of the ocean in winter it drops below 0 °. S, off the coast. In Antarctica, low temperatures are also typical for the summer months. In tropical latitudes, trade winds dominate the ocean. In temperate latitudes, westerly winds prevail over the ocean, and off the coast. Eurasia - monsoons. Strong winds often blow over the ocean - storms and tropical cyclones - typhoons. The maximum amount of precipitation (close to 3000 mm) falls in the western part of the equatorial belt, the minimum - in the eastern regions between the equator and the southern tropic (about 100 mm to 100 mm).
Properties of waters and ocean currents
In the Pacific Ocean all types of surface water masses are formed, except for the Arctic ones. The average annual water temperature between the tropics is 19°. N, at the equator - 25 ° 29 °. S, V. In Antarctica it drops to -1°. C. Ice phenomena in the northern part of the ocean and in the subantarctic belt are seasonal. Up close. Antarctica's sea ice lasts all over Russia.
Precipitation over the ocean generally dominates evaporation. Salinity of surface waters. The Pacific Ocean is slightly lower than in. Atlantic
The ocean is quite elongated from west to east, so latitudinal water flows predominate in it. In the Pacific Ocean a system of ocean currents was formed, which in. In the northern hemisphere it is shaped like a huge figure eight. This system includes currents:. Northern. Passatnoe,. Kuroshio,. Pivnichnopacific and. Californian. South of the equator it becomes ring-shaped, including. Southern trade wind. ShidnoAustralian ku,. Western. Vetrov and. Peruvian current.
Organic world
By the number of species and biomass, the organic world. The Pacific Ocean is richer than other oceans. This is due to its size, diversity of natural conditions and long geological history. Organic life is especially rich in equatorial-tropical latitudes, in areas where coral reefs are distributed. The northern part of the ocean is characterized by various species of fish, including salmon.
Natural complexes
In the Pacific Ocean there are almost all natural zones, except for the North Polar
Northern. The subpolar belt occupies a small part. Beringova and. Sea of Okhotsk. In this zone there is intense circulation of cool waters, and therefore they are rich in oxygen, and therefore fish
The northern temperate zone covers large areas of water between. Eurasia and. Northern. America. It is characterized by the interaction of warm and cold water masses. It is characterized by a particularly large species diversity of organisms. Japanese morra.
Northern subtropical zone c. The Pacific Ocean is not as clearly expressed as the temperate one. The western part of the heat belt, the eastern part is cold. The waters are weakly mixed, they are transparent, blue, and the amount of plankton and fish is small.
The northern tropical zone is formed under the influence of a powerful... Northern trade wind currents. This belt contains a large number of individual islands and archipelagos
In the equatorial belt, a complex interaction of various currents occurs. At the junctions of streams
whirlpools contribute to the rise of waters, their biological productivity increases
In the Southern Hemisphere, the same natural belts are formed as in. Northern. However, they differ in some properties of water masses and the species composition of organisms. For example, notothenia and white-blooded fish live in the waters of the subantarctic and anta arctic zones. In the southern tropical zone off the coast. South. America, between 4 and 23 ° S, a special water complex is formed. It is characterized by a stable and intense rise of deep waters and the active development of organic life. This is one of the best areas of everything. World ocean ocean.
Economic use
The Pacific Ocean plays an important role in the lives of many countries and peoples. The ocean and its seas wash the coasts of continents on which more than 30 coastal states are located with a total population of more than 2 billion people.
In the waters. The Pacific Ocean has a wide variety of natural resources on its bottom and shores. The main types of wealth include biological resources. Ocean waters are characterized by high productivity (about 200 kg/km). Ocean fisheries account for more than 60% of the world's catch.
Table and potassium salts, magnesium, bromine are extracted from sea water; sea water desalination plants are in operation. On the ocean shelf, deposits of tin ores and other metals are being developed, and large amounts of oil and gas are being extracted.
The energy resources of the Pacific waters are large and diverse, but are still poorly used
The routes of global and regional shipping pass through the Pacific Ocean; there are many ports on the ocean’s shores
In recent years, economic activities have led to severe pollution of some ocean areas, especially off the coast. Japan and. Northern. America. The stocks of fish, whales and other animals have been depleted, and some of them have lost their commercial value.
Due to the fact that the main factor that generates zonality in the oceans - the angle of incidence of the sun's rays - affects primarily the upper layers of water through temperature and light, zonation is most clearly and multifacetedly manifested in the surface 100-meter layer of water and, in a weakened form, extends to depths up to 500 m. Some geographers believe that zoning does not apply to the rest of the oceanic waters. But this is not so, because bottom processes, sedimentation material, and the emerging composition of bottom sediments depend on the organic world and processes occurring in the upper 500-meter layer of ocean waters. In this case, the entire intermediate layer of oceanic waters (from 500 m depth to the bottom layer) is a connecting link through which material flows from the surface layers to the ocean floor. Thus, the idea that zonality in the thickness of oceanic waters, to one degree or another, in one form or another, can be traced throughout their entire depth, acquires legitimacy.
Arctic seas zone extends in the south of the Atlantic to 70° N, in the south of the Pacific to 60° N.
The annual radiation balance is less than 20 kcal/cm2. Almost everywhere (except for the southern Pacific Ocean) polar day and polar night of varying durations are observed depending on the geographic latitude.
Air temperature: in winter -2 - -40°, in summer 0 - +10°; waters: in winter -1 - -2°, in summer up to +8° on the shelves.
Arctic air masses dominate year-round. Winds predominate from the east and northeast in the interior of the Arctic Ocean. Around the Greenland Anticyclone, air flowing from the ice sheet forms winds that diverge in all directions, deviating to the right. A monsoon circulation forms along the coasts of Asia and North America: southwest winds in winter, northeasterly winds in summer. Annual precipitation is 75–350 mm, up to 500 mm in the area of warm Atlantic currents.
Water salinity 30–32‰; on the shelf, due to the influx of river waters, salinity decreases to 25‰. The main current in the Arctic Ocean occurs in the area of the Chukotka and East Siberian shelves. It crosses the ocean in a wide strip through the North Pole and rushes to the northern coast of Greenland, where its waters flow into the Atlantic between Greenland and Spitsbergen. On both sides of this general current, two current gyres are formed: one is located towards Alaska over the Canadian Basin, the other is located east of Severnaya Zemlya. Currents in the Atlantic (Norwegian and East Greenland) and Pacific (Alaskan and Kuril-Kamchatka) oceans form water flows directed from east to west. At the same time, warm currents are confined to the eastern, cold currents - to the western margins of the oceans.
Ice covers about 70% of the zone's area in winter, and about 50% in summer. During the autumn-winter freezing of water, a significant part of the salts is displaced from it, as a result the ice becomes desalinated, and the waters under the ice become salinized and, becoming heavier, sink down, sometimes to the bottom, which leads to mixing of waters to great depths. This slows freeze-up as the cooling surface waters sink and it takes additional time for the water rising from the depths to cool. Pack ice is 3–4 m thick, in hummocks it is up to 25 m. The East Greenland and Kuril-Kamchatka currents transport sea drifting ice and icebergs to lower latitudes.
The water is rich in oxygen and, due to this, there is an abundance of diatom plankton in the surface layer. Along the coast algae are common - green, brown, red and zoster sea grass. Lots of fish: herring, cod, haddock, sea bass, navaga, polar flounder. Herring usually spawns in zoster thickets, so a drop in the productivity of the latter due to anthropogenic pollution of the waters in the White Sea has a negative impact on the herring fishery. The ice of the Arctic Ocean is characterized by cryophilic animals: pinnipeds include walruses and seals, as well as cetaceans, although the latter are greatly exterminated.
Bottom sediments of the marginal seas of the Arctic and Pacific oceans are predominantly of terrigenous origin, they are poor in lime and organic matter; brown and gray silts predominate. The shallow waters of marginal seas contain products of ice rafting in the composition of bottom sediments. In open waters, diatomaceous sediments containing 30–56% authigenic silica are widespread.
The shores for a long distance are fjords and skerry beaches with “bird colonies” of seabirds that feed and raise their offspring at the expense of the food resources of the oceans.
North temperate zone has a southern border in the Atlantic 45° N, in the Pacific Ocean 50° N.
The annual radiation balance is 20–40 kcal/cm2.
Air temperature: in winter -5 - +10°, in summer +5 - +15°; water: in winter +4 - +10°, in summer +10 - +15°.
Marine, predominantly moderate air masses dominate all year round. Westerly winds predominate. The monsoon circulation is pronounced over the western edge of the Pacific Ocean: northwestern winds in winter and southeastern winds in summer. Between 65 and 60° N latitude. Cyclones pass along the polar front from west to east. Annual precipitation is 500–1000 mm.
Water salinity is 33–35‰. Surface ocean currents form cyclonic gyres around the Icelandic and Aleutian lows. At the same time, warm currents are formed in the eastern parts of the oceans, and cold currents in the western parts.
Vegetation in coastal areas is represented by fucus and kelp algae. The plankton is dominated by diatoms, foraminifera and copepods. The animal world in the Atlantic Ocean is characterized by: toothed whales (sperm whales), pinnipeds (harp seal, seal); fish - herring, cod, haddock, saury, sea bass; in the Pacific Ocean: among cetaceans - Japanese and gray whales; among pinnipeds - fur seal and sea otter (sea otter); fish - herring, pink salmon, chum salmon, cod, flounder, ivashi, crabs are common.
Ocean bottom sediments vary significantly across oceans. The Atlantic Ocean is characterized by terrigenous sediments, calcareous and foraminiferal silts (the latter in the northern part due to the warming of waters by ocean currents); for the Pacific Ocean - terrigenous silty-clayey silts, weakly manganese or weakly ferruginous, with a noticeable content of authigenic silica, as well as red clays.
The coasts are home to the distribution areas of ocean-associated birds - gulls, guillemots, auks, and guillemots.
Circulation zone of northern trade wind currents can be traced in three oceans: the Atlantic, Indian and Pacific. The southern border: in the Atlantic and Pacific oceans at 8° N, in the Indian - almost to the equator.
The annual radiation balance is 40–100 kcal/cm2.
Air temperatures: in winter +7 - +25°, in summer +15 - +25°; water: in winter +5 - +25°, in summer +10 - +15°.
Marine tropical air masses dominate year-round. The zone is latitudinally intersected in the Atlantic and Pacific oceans by the northern subtropical high pressure belt; to the north of it, southwestern trade winds dominate, to the south - northeastern trade winds. There is a monsoon circulation over the Indian Ocean within the zone: northeast winds in winter, southwest winds in summer. Annual precipitation increases from 100 mm in the east of the Atlantic and Pacific oceans to 3000 mm on their western margins, which is associated with the gradual saturation of trade winds as they move from cold in the east to warm ocean currents in the west. In the Indian Ocean, precipitation increases in the opposite direction, due to the existence of the summer equatorial monsoon, the effect of which increases to the east, while in the west the cold Somali Current at this time contributes to a decrease in precipitation. The trade wind from the Sahara carries dust over the Atlantic Ocean far to the west - up to 37° west. and 7° N Hurricanes and typhoons are observed annually in the areas of the Gulf Stream, Arabian Sea, Bay of Bengal and Kuroshio Current.
The salinity of ocean waters is 33–37.5‰, relatively high in the calm zone and trade winds. The highest salinity - up to 42‰ - is in the Red Sea. Ocean currents in the Atlantic and Pacific oceans form gyres around the Azores High - the North Trade Wind, the Antilles, the Gulf Stream, the Gulf Stream "delta", the Canary Current, and around the Hawaiian High - the North Trade Wind, Kuroshio, North Pacific, California Currents. At the same time, cold currents form on the eastern edges of these oceans. Inside the Atlantic Rim is the Sargasso Sea. In the Indian Ocean, within the zone there are the Somali and Monsoon currents associated with the monsoon circulation.
The vegetation of coastal areas of the oceans is dominated by fucus algae, in the Sargasso Sea - sargassum algae (their quantity is estimated at 15 million tons). Plankton is represented by foraminifera, copepods, pteropods, cephalopods, jellyfish and siphonophores. Typical representatives of the fauna: among toothed whales - sperm whales; fish - golden mackerel, flying fish, tuna, sharks, stingrays; among reptiles - sea turtles, sea snakes, moray eels; There are annelids, sea cucumbers, and pearl mussels. Birds associated with the sea are herring gulls, phaetons, frigates.
Bottom sediments are characterized by the carbonate type of sedimentation. In shallow waters, chemogenic carbonate formation is observed. In the coastal parts of the oceans, terrigenous sediments - red silts - are common.
The south of the zone is rich in coral structures; mangroves are found on the coasts in places of sufficient moisture.
Coral sea zone expressed in three oceans: Atlantic, Indian and Pacific. Southern border at 6° S.
The annual radiation balance is 100–120 kcal/cm2. The climate is hot and humid. Frequent thunderstorms, showers, cloudy skies.
Air temperatures all year round are more than +25°, with daily fluctuations greater than seasonal ones.
Water temperatures all year round are +25 - +28°.
The zone is an area of calms and weak winds. The circulation is monsoonal: in January winds from the north prevail, and in July from the south. Heavy precipitation is typical for the entire zone: the annual amount is 2000–3000 mm. Excessive moisture.
The water salinity is below 35‰ due to heavy rainfall. Equatorial countercurrents are expressed in the zone: in the Atlantic Ocean only in the summer of the northern hemisphere (since the Azores Maximum and the Northern Trade Wind Current are shifted to the north following the zenithal position of the Sun, and the Southern Trade Wind Current cannot shift to the north, because near the Gulf of Guinea. The Guinea Current is catching up southwest monsoon all year due to the fact that off the western coast of Africa the intertropical pressure depression is located north of the equator all year under the influence of the cold Benguela Current); in the Indian Ocean - only in the summer of the southern hemisphere (when the northeastern monsoon acquires a trade wind direction and the movement of water by the trade winds of both hemispheres to the west causes a compensatory flow in the eastern direction), and in the Pacific Ocean - all year round.
For the organic world of the zone, the composition of phyto- and zooplankton is characterized by nocturnal lights (at night they cause the sea to glow - the “milky sea”). Algae include trichodesmia and sargassum. The mangroves are home to hermit crabs, oysters, pelicans, flamingos, ibises, frigate birds, chaises, and mosquitoes.
There are a lot of coral structures - atolls, reefs, archipelagos. In addition to corals, calcareous algae, bryozoans, mollusks, and foraminifera take part in their structure. Near the coral structures live starfish and sea urchins, mollusks (octopus, cuttlefish, pearl mussels), sponges, coral fish, poisonous conger eel (moray eel), and palolo annelid worm. Coconut palm trees grow on the islands, with which the palm thief crab is associated with food (he climbs onto a palm tree, bites off a coconut, it falls, breaks, and the crab feeds on its contents).
Radiolarian oozes are common among bottom sediments. Organic-clastic deposits predominate near coral structures.
Circulation zone of southern trade wind currents expressed in three oceans: Atlantic, Indian and Pacific. Southern border at 40° S.
The annual radiation balance is 100–60 kcal/cm2.
Air temperatures: in winter +10 - +25°, in summer +15 - +28°; water - the same.
Marine tropical air masses dominate year-round. In all three oceans, the zone is latitudinally intersected by the southern subtropical high pressure belt. To the north of it, southeast trade winds dominate, to the south - northwest winds. Annual precipitation increases from 100 mm in the east of each ocean to 3000 mm on the western margins, which is associated with the gradual saturation of trade winds as they move from cold ocean currents to warm ones. The exception is the southeastern edge of the Pacific Ocean within the zone where northwest winds, encountering the obstacle of the Andes mountain range on the windward slopes, produce heavy precipitation (more than 200 mm). Tropical cyclones, sometimes of hurricane force, form annually off Madagascar, the Fiji Islands and east of Australia.
The salinity of ocean waters is 34–37.5‰, the highest in the zone of calm and trade winds, which is associated with an increase in water temperature from south to north. Ocean currents form anticyclonic gyres: around the South Atlantic High - the Southern Trade Wind, the Brazilian, the Western Winds, and the Benguela; around the Indian maximum - South trade wind, Mozambique, Agulhas, Western winds, Western Australian; around the South Pacific High - Southern Trade Wind, East Australian, Western Winds, Peruvian Currents. At the same time, cold currents form on the eastern edges of the oceans.
The organic world is close to the circulation zone of northern trade wind currents.
In the north of the zone, coral structures are common; mangroves are found on the coasts in places of sufficient moisture.
For bottom sediments, as in the circulation zone of northern trade wind currents, the main feature is the sharp predominance of the carbonate type of sedimentation. Foraminiferal, coccolithic, pteropodal, coral and shell sediments predominate. Chemogenic carbonate formation occurs in shallow waters. Associated with coral structures are coral sands and muds. Deep-water areas below 5000 m are occupied by red clay.
Sea Prairie Zone extends south to 50° S. in the same three oceans, where they merge into a single oceanic belt.
The annual radiation balance is 60–40 kcal/cm2.
Air temperatures: in winter +5 - +12°, in summer +8 - +16°; water: in winter 0 - +12°, in summer +8 - +16°.
Temperate sea air masses and north-westerly winds prevail year-round. Because of the strong and constant winds, these latitudes of the oceans are called: the Roaring Forties. Fogs are frequent and there are no thunderstorms. Annual precipitation is more than 1000 mm, and off the west coast of South America - up to 3000 mm.
The water salinity is up to 35‰, and is distributed relatively evenly over the water area. The entire zone is covered by the powerful current of the Western Winds (or Antarctic), penetrating in a somewhat weakened form into the neighboring circulation zone of the southern trade wind currents. From the south, the current is limited by the line of convergence of temperate and Antarctic waters. The following waves are observed: long swell - with a wavelength of more than 300 m, the wave height is 2–3 m; in stormy winds the wave height is up to 30–35 m.
The organic world is characterized by accumulations of drifting algae; kelp reaches 50 m in length, hence the name “sea prairie zone.” The northern boundary of the zone coincides with the boundary of the mass distribution of southern whales and nototheniid fish. South polar birds nest on the islands.
Bottom sediments of the zone do not differ in clearly defined specificity. Foraminiferal muds predominate, while coral sediments and reef structures are absent. In the southern part of the zone, transitional calcareous-siliceous sediments appear, formed as a result of the appearance of a noticeable admixture of diatom remains to foraminiferal material.
Middle Southern Ocean extends south in the Atlantic and Indian Oceans to 60° S. and in the Pacific Ocean to the Arctic Circle.
The annual radiation balance is 40–20 kcal/cm2. The zone is confined to the subantarctic landscape belt.
Air temperatures: in winter -8 - +6°, and in most of the area the temperatures are negative, in summer 0 - +8°; water temperature: in winter -1 - +6°, with ice appearing in places, in summer 0 - +8°.
The air masses in winter are Antarctic, in summer they are maritime temperate. Winds in the northern part are predominantly northwest, and weaken to the south. In the southern part, southeast winds are stronger, especially in winter. The climate is cool. Annual precipitation is 500–1000 mm. Precipitation in the form of snow in winter, rain in summer. Excessive moisture.
The water salinity is usually below 34.5‰. Floating ice reaches 55° S, icebergs, especially large ones, often cross the zone, their predominant drift is to the east.
The waters are rich in oxygen, phosphates, and silicic acid (the food source for diatoms). There are many kilometers of accumulations of krill (dark-eye crustacean). Brown algae is common around the islands. The cetacean fauna includes blue whale, fin whale, soy whale; from fish - nototheniaceae; South polar birds nest on the islands; Penguins often drift with ice floes and icebergs.
Based on bottom sediments, the zone is clearly distinguished by the wide distribution of siliceous diatom sediments. Unlike diatom sediments in the Arctic seas, the silica content here reaches 70–80%. An admixture of iceberg material is also noticeable.
Southern Arctic Seas Zone occupies the southernmost part of the oceans all the way to the coast of Antarctica.
The annual radiation balance is less than 20 kcal/cm2. Polar night and polar day of varying lengths are observed.
Air temperatures: in winter -10 - -25°, in summer from negative to +5°; water temperatures: in winter everywhere below 0°, in summer from negative to +2°.
The air masses are Antarctic all year round. The winds are not pronounced; near the coasts there are strong katabatic and south-easterly winds. Annual precipitation is 300–600 mm, precipitation mainly in the form of snow.
Water salinity is 33–34‰. The currents are not clearly expressed. Along the coasts, there is a movement of water to the west under the influence of katabatic winds. Floating sea ice is salty; when the winds blow, waves break it up and hummocks form; Continental ice is fresh, represented by icebergs, they are predominantly table-shaped (formed when separated from ice shelves), reach tens of kilometers in diameter and exist for up to 10 years.
The plankton is dominated by diatoms, copepods, and transparent pteropods. Nototheniids predominate among fish. Birds that live on the shore are connected to the ocean waters by food chains: albatrosses, giant petrels, cormorants, skuas, kelp gulls; penguins (emperor, chinstrap, adélie, etc.) live in colonies of up to a million animals. Common cetaceans include blue whale, humpback whale, fin whale, soy whale; among pinnipeds - elephant seal, crabeater seal, etc.
Iceberg deposits are predominantly distributed on the seabed. They are characterized by poor sorting, low content of lime and organic matter, and a noticeable content of authigenic silica. On the shelf, in addition to iceberg sediments of various compositions, there are also siliceous-sponge deposits.
General information and physical-geographical location
The Pacific (Great) Ocean is located in all hemispheres of the Earth, between the continents of Eurasia and Australia in the west, North and South America in the east and Antarctica in the south.
The Pacific Ocean occupies more than 1/3 of the planet's surface and almost half of the World Ocean. The coastline is relatively straight off the coasts of North and South America and highly dissected off the coast of Eurasia. The Pacific Ocean includes a number of marginal seas of East and Southeast Asia. There are a large number of archipelagos and individual islands in the ocean.
Bottom relief
The Pacific Ocean has a very complex bottom topography. The shelf occupies a small area. Off the coast of North and South America its width does not exceed tens of kilometers, and off the coast of Eurasia it is measured in hundreds of kilometers. In the peripheral parts of the ocean there are deep-sea trenches. The Pacific Ocean contains the majority of the deep-sea trenches of the World Ocean (25 x 35, having a depth of more than 5 km) and all four trenches are more than 10 km deep. Among the latter is the Mariana Trench with the deepest mark of the bottom of the World Ocean - 11022 m. Large uplifts, individual mountains and ridges divide the ocean floor into basins. In the southeast there is the Pacific Rise, which is part of the system of mid-ocean ridges.
Most of the ocean lies on the Pacific lithospheric plate and interacts with neighboring
slabs. It is with the interaction zones that deep-sea trenches and island arcs are associated.
Associated with the system of deep-sea trenches and mountain structures on the continents and islands surrounding the ocean is an almost continuous chain of active volcanoes that form the Pacific “Ring of Fire.” In this area, land and underwater earthquakes are frequent, causing tsunami waves.
Climate
The Pacific Ocean is located in almost all climate zones. Most of it lies in the equatorial, subequatorial and tropical zones. The air temperature over these waters throughout the year is + 16 ° ... + 24 ° C. In the north of the ocean in winter it drops below 0 ° C; off the coast of Antarctica, low temperatures are also typical for the summer months. In tropical latitudes, trade winds dominate the ocean. In temperate latitudes, westerly winds prevail over the ocean, and monsoons prevail off the coast of Eurasia. Strong winds often blow over the ocean - storms and tropical cyclones - typhoons. The maximum amount of precipitation (about 3000 mm) falls in the western part of the equatorial belt, the minimum in the eastern regions between the equator and the southern tropic (about 100 mm).
Properties of waters and ocean currents
All types of surface water masses, except Arctic ones, are formed in the Pacific Ocean. The average annual water temperature between the tropics is + 19 ° C, near the equator - + 25 ° ... + 29 ° C, in Antarctica it drops to -1 ° C. Ice phenomena in the northern part of the ocean and in the subantarctic zone are seasonal. Antarctica's sea ice lasts all year.
Precipitation over the ocean generally dominates evaporation. The salinity of the surface waters of the Pacific Ocean is slightly lower than that of the Atlantic.
The ocean is quite elongated from west to east, so latitudinal water flows predominate in it. A system of ocean currents has formed in the Pacific Ocean, which in the Northern Hemisphere has the shape of a huge figure eight. This system includes currents: the North Trade Wind, Kuroshio, North Pacific and California. South of the equator it becomes an annular shape, encompassing the South Trade Winds, the East Australian Winds, the West Winds and the Peruvian Current.
Organic world
In terms of the number of species and biomass, the organic world of the Pacific Ocean is richer than in other oceans. This is due to its size, diversity of natural conditions and long geological history. Organic life is especially rich in equatorial-tropical latitudes, in areas where coral reefs are distributed. The northern part of the ocean is characterized by various species of fish, including salmon.
Natural complexes
In the Pacific Ocean there are almost all natural zones, except for the North Polar.
The northern subpolar belt occupies a small part of the Bering and Okhotsk seas. In this zone there is intense circulation of cold waters, and therefore they are rich in oxygen, and, accordingly, fish.
The northern temperate zone covers vast areas between Eurasia and North America. It is characterized by the interaction of warm and cold water masses. The Sea of Japan is characterized by a particularly large species diversity of organisms.
The northern subtropical zone in the Pacific Ocean is not as clearly defined as the temperate zone. The western part of the heat belt, the eastern part is cold. The waters are weakly mixed, they are transparent, blue, the amount of plankton and fish is small.
The northern tropical belt is formed under the influence of the powerful North Trade Wind Current. This belt contains a large number of individual islands and archipelagos.
In the equatorial belt, a complex interaction of various currents occurs. At the junctions of streams
whirlpools contribute to the rise of waters, their biological productivity increases.
The same natural belts are formed in the Southern Hemisphere as in the Northern Hemisphere. However, they differ in some properties of water masses and the species composition of organisms. For example, notothenia and white-blooded fish live in the waters of the subantarctic and Antarctic zones. In the southern tropical zone off the coast of South America between 4 and 23 ° S. w. a special water complex is formed. It is characterized by a steady and intense rise of deep waters and the active development of organic life. This is one of the most areas of the entire World Ocean.
Economic use
The Pacific Ocean plays an important role in the lives of many countries and peoples. The ocean and its seas wash the coasts of continents on which more than 30 coastal states are located with a total population of more than 2 billion people.
There are many different natural resources in the waters of the Pacific Ocean, on the bottom and on the shores. The main types of wealth include biological resources. Ocean waters are characterized by high productivity (about 200 kg/km). Ocean fisheries account for more than 60% of the world's total.
Kitchen and potassium salts, magnesium, bromine are extracted from sea water; sea water desalination plants are in operation. On the ocean shelf, deposits of tin ores and other metals are being developed, and large amounts of oil and gas are being extracted.
The energy resources of the Pacific waters are large and varied, but are still poorly used.
The Pacific Ocean is the route for global and regional shipping, and there are many ports on the ocean’s shores.
In recent years, economic activities have led to severe pollution of some ocean areas, especially off the coast of Japan and North America. Stocks of fish, whales and other animals have been depleted, some of which have lost their industrial importance.
The northern subpolar belt has some features. It is not directly influenced by the waters of the Arctic basin, and powerful jets of warm, highly saline waters do not penetrate here. It is dominated by cold waters. Within the belt there are extensive shelves. On the shallow shelf, nutrients are not lost irretrievably at great depths, but are included in the cycle of organic matter, so shelf waters are characterized by high biological and commercial productivity.
The northern tropical belt stretches from the coasts of Central America to and continues to the coasts and into the South China Sea. A significant part of the belt is dominated by the trade winds of the Northern Hemisphere and the Northern Trade Wind Current. It is developed in the western part. The belt is characterized by high water temperatures and salinity, and low bioproductivity.
The southern subtropical belt stretches in a winding strip of variable width from Southeast Australia and to the east, covering most of the Tasman Sea, the region, the space between 30 and 40° S. sh., closer to the shores, descends to slightly lower latitudes and approaches the coast between 20 and 35° S. w. The deviation of the boundaries from the latitudinal strike is associated with the circulation of surface waters and the atmosphere. The axis of the belt in the open part of the ocean is the subtropical convergence zone, where the waters of the South Trade Wind Current and the northern jet of the circumpolar current converge. The position of the convergence zone is unstable, depends on the season and changes from year to year, but the main processes typical of the belt are constant: the lowering of air masses, the formation of a high pressure area and marine tropical air, and salinization of waters. On the eastern edge of the belt along the coast of Chile, the coastal Peruvian Current can be traced from south to north, where intense flow and rise of water occurs, resulting in the formation of a subtropical upwelling zone and the creation of large biomass.
The southern temperate zone includes the large northern part of the Antarctic Circumpolar Current. The northern boundary of the belt is close to 40-45° S. sh., and the southern one passes about 61-63° S. sh., i.e. along the northern border of the distribution of sea ice in September. The southern temperate zone is an area dominated by western, northwestern and southwestern, stormy, significant, low winter and summer surface waters and intensive transport of surface waters to the east.
