In terms of the number of islands and archipelagos, the Arctic Ocean ranks second after the Pacific Ocean. This ocean contains such large islands and archipelagos as Greenland, Franz Josef Land, New Earth, Severnaya Zemlya, Wrangel Island, New Siberian Islands, Canadian Arctic Archipelago.

The Arctic Ocean is divided into three large water areas:

1. Arctic Basin; The center of the ocean, its deepest section reaches 4 km.
2. North European Basin; It includes the Greenland Sea, the Norwegian Sea, the Barents Sea and the White Sea.
3. Mainland Shoal; Includes the seas that wash the continents: the Kara Sea, the Laptev Sea, the East Siberian Sea, the Chukchi Sea, the Beaufort Sea and the Baffin Sea. These seas account for more than 1/3 of the total ocean area.

It is quite simple to imagine the topography of the ocean floor in a simplified manner. The continental shelf (maximum width 1300 km) ends with a sharp decrease in depth to 2-3 km, forming a kind of step that surrounds the central deep-sea part of the ocean.

This natural bowl is more than 4 km deep in the center. dotted with many underwater ridges. In the 50s of the 20th century, bottom echolocation showed that the Arctic Ocean is dissected by three trans-oceanic ridges: Mendeleev, Lomonosov and Gakkel.

The waters of the Arctic Ocean are fresher than other oceans. This is explained by the fact that large rivers of Siberia flow into it, thereby desalinating it.

Climate

From January to April there is an area in the center of the ocean high pressure, better known as the Arctic anticyclone. In the summer months, on the contrary, lower pressure prevails in the Arctic basin. The pressure difference constantly brings cyclones, precipitation and winds of up to 20 m/s to the Arctic Ocean from the Atlantic. On the way to the center of the ocean great amount cyclones pass through the North European Basin, causing sudden changes weather, heavy rainfall and fog.

The air temperature ranges from -20 to -40 degrees. In winter, when 9/10 of the ocean area is covered with drifting ice, the water temperature does not rise above 0 degrees Celsius, dropping to -4. The thickness of the drifting ice floes is 4-5 meters. Icebergs are constantly found in the seas surrounding Greenland (Baffin Sea and Greenland Sea). By the end of winter, the ice area reaches 11 million square meters. km. Only the Norwegian, Barents and Greenland Seas remain ice-free. These seas flow into warm waters North Atlantic Current.

In the Arctic basin, ice islands drift, the ice thickness of which is 30-35 meters. The “lifetime” of such islands exceeds 6 years and they are often used to operate drifting stations.

By the way, Russia is the first and only country that uses drifting polar stations. Such a station consists of several buildings where expedition members live and a set of necessary equipment is located. The first such station appeared in 1937 and was called “North Pole”. The scientist who proposed this method of researching the Arctic is Vladimir Wiese.

Fauna of the Arctic Ocean

Until the 20th century, the Arctic Ocean was a “dead zone”; research was not carried out there due to very harsh conditions. Therefore, knowledge about the animal world is very scarce.

The number of species decreases as you approach the center of the ocean in the Arctic basin, but phytoplankton develops everywhere, including under drifting ice. This is where feeding fields for various minke whales are located.

The colder areas of the Arctic Ocean are favored by animals that can easily withstand harsh climatic conditions: narwhal, beluga whale, polar bear, walrus, seal.

In more favorable waters of the North European Basin animal world more diverse due to fish: herring, cod, sea bass. There is also the habitat of the now almost exterminated bowhead whale.

The fauna of the ocean is gigantic. Giant mussels, giant cyanide jellyfish, and sea spider live here. The slow progression of life processes endowed the inhabitants of the Arctic Ocean with longevity. Recall that the bowhead whale is the longest-living vertebrate on Earth.

The flora of the Arctic Ocean is unusually sparse, because... drifting ice does not allow the sun's rays to pass through. With the exception of the Barents and White Seas, the organic world is represented by unpretentious algae, which predominate in the continental shallows. But in terms of the amount of phytoplankton, the seas of the Arctic Ocean can easily compete with more southern seas. There are more than 200 species of phytoplakton in the ocean, almost half of them are diatoms. Some of them have adapted to live on the very surface of the ice and during the flowering period they cover it with a brown-yellow film, which, by absorbing more light, causes the ice to melt faster.

The seas of the Arctic Ocean are located in the Arctic zone between 70 and 80° N. w. and wash the northern coast of Russia. From west to east, the Barents, White, Kara Sea, Laptev Sea, East Siberian and Chukchi Seas replace each other. Their formation occurred as a result of the flooding of the marginal parts of Eurasia, as a result of which most of the seas are shallow. Communication with the ocean is carried out through wide open spaces of water. The seas are separated from each other by the archipelagos and islands of Novaya Zemlya, Severnaya Zemlya, the New Siberian Islands and Wrangel Island. The natural conditions of the northern seas are very harsh, with significant ice cover from October to May - June. Southwestern part only Barents Sea, where the branch of the warm North Atlantic Current enters, remains free of ice all year round. The biological productivity of the seas of the Arctic Ocean is low, which is associated with unfavorable conditions for the development of plankton. The greatest ecosystem diversity is characteristic only of the Barents Sea, which is also of great fishing importance. The Northern Sea Route passes through the seas of the Arctic Ocean - the shortest distance from the western borders of Russia to the north and Far East - it has a length of 14,280 km from St. Petersburg (via the North and Norwegian Seas) to Vladivostok.

Barencevo sea

The Barents Sea washes the coasts of Russia and Norway and is limited by the northern coast of Europe and the archipelagos of Spitsbergen, Franz Josef Land and Novaya Zemlya (Fig. 39). The sea is located within the continental shallows and is characterized by depths of 300-400 m. South part The sea has a predominantly leveled relief, the northern part is characterized by the presence of both hills (Central, Perseus) and depressions and trenches.
The climate of the Barents Sea is formed under the influence of warm air masses from the Atlantic and cold Arctic air from the Arctic Ocean, which causes great variability in weather conditions. This leads to significant temperature variations in different parts water areas. In the coldest month of the year—February—the air temperature varies from 25 °C in the north to -4 °C in the southwest. Usually cloudy weather prevails over the sea.
The salinity of the surface layer of water in the open sea throughout the year is 34.7-35%o in the southwest, 33-34%o in the east, and 32-33%o in the north. In the coastal strip of the sea in spring and summer, salinity drops to 30-32% o, by the end of winter it increases to 34-34.5%.

IN water balance Barents Sea great importance has water exchange with neighboring water areas. Surface currents form a counterclockwise gyre. The role of the warm North Cape Current (a branch of the Gulf Stream) is especially important in the formation of the hydrometeorological regime. In the central part of the sea there is a system of intracircular currents. The circulation of sea waters changes under the influence of changes in winds and water exchange with adjacent seas. Along the coasts, the importance of tidal currents increases, characterized as semidiurnal, the highest height of which is 6.1 m near the Kola Peninsula.
Ice cover reaches most widespread in April, when at least 75% of the sea surface is occupied by floating ice. However, its southwestern part remains ice-free in all seasons due to the influence of warm currents. The northwestern and northeastern margins of the sea are completely free of ice only in warm years.
The biodiversity of the Barents Sea stands out among all the waters of the Arctic Ocean, which is associated with natural and climatic conditions. There are 114 species of fish found here, 20 of which are of commercial importance: cod, haddock, herring, sea bass, halibut and others. The benthos is very diverse, among which are common sea ​​urchins, echinoderms, invertebrates. Introduced back in the 30s. XX century Kamchatka crab adapted to new conditions and began to reproduce intensively on the shelf. The coasts abound with bird colonies. Large mammals include the polar bear, beluga whale, and harp seal.
Haddock, a fish of the cod family, is an important fishery species in the Barents Sea region. Haddock makes long-distance feeding and spawning migrations. Haddock eggs are carried by currents over long distances from their spawning grounds. Fry and juveniles of haddock live in the water column, often hiding from predators under the domes (bells) of large jellyfish. Adult fish lead a predominantly bottom-dwelling lifestyle.
Serious ecological problems in the Barents Sea are associated with contamination by radioactive waste from Norwegian processing plants, as well as with the flow of contaminated water from the land surface. The greatest pollution with oil products is typical for the Kola, Teribersky and Motovsky bays.

White Sea

White Sea belongs to the category of internal and is the smallest among the seas washing Russia (Fig. 40). Washes South coast Kola Peninsula and is separated from the Barents Sea by a line connecting Capes Svyatoy Nos and Kanin Nos. The sea is replete with small islands, among which the most famous are Solovetsky. The shores are indented by numerous bays. The bottom relief is complex; in the central part of the sea there is a closed basin with depths of 100–200 m, separated from the Barents Sea by a threshold with shallow depths. The soils in shallow water are a mixture of pebbles and sand, turning into clayey silt at depths.
The geographic location of the White Sea determines the climatic conditions, where features of both marine and continental climates appear. In winter, cloudy weather sets in with low temperatures and heavy snowfalls, and the climate in the northern part of the sea is somewhat warmer, which is due to the influence of warm air and water masses from the Atlantic. IN summer time The White Sea is characterized by cool, rainy weather with average temperatures of +8–+13°C.

Admission fresh water and insignificant water exchange with neighboring water areas determined the low salinity of the sea, which is about 26%o near the coasts and 31%o in deep zones. In the centric part, an annular flow is formed, directed counterclockwise. Tidal currents are semi-diurnal in nature and range from 0.6 to 3 m. In narrow areas, the height of the tide can reach 7 m and penetrate high up the rivers up to 120 km (Northern Dvina). Despite its small area, storm activity is widespread in the sea, especially in the autumn; the White Sea freezes annually for 6-7 months. Fast ice forms near the coast, the central part is covered with floating ice, reaching a thickness of 0.4 m, and in severe winters - up to 1.5 m.
The diversity of ecosystems in the White Sea is much lower than in the neighboring Barents Sea, however, various algae and bottom invertebrates are found here. Among marine mammals, the harp seal, beluga whale, and ringed seal should be noted. In the waters of the White Sea there are important commercial fish: navaga, White Sea herring, smelt, salmon, cod.
In 1928, Soviet hydrobiologist K.M. Deryugin noted in the White Sea the presence of a number of endemic forms due to isolation, as well as a shortage of species compared to the Barents Sea, which is associated with the peculiarities of the hydrodynamic regime. Over time, it became clear that there are no endemics in the White Sea, all of them are either reduced to synonyms, or are still found in other seas.
The water area has a large transport value, as a result of which the ecological condition of certain areas of the water area is deteriorating, especially associated with the transportation of petroleum products and chemical raw materials.

Kara Sea

The Kara Sea is the coldest sea washing the shores of Russia (Fig. 41). It is limited to the coast of Eurasia in the south and the islands: Novaya Zemlya, Franz Josef Land, Severnaya Zemlya, Heiberg. The sea is located on the shelf, where depths range from 50 to 100 m. In shallow water, sandy soil dominates, and the gutters are covered with silt.
The Kara Sea is characterized by a marine polar climate, which is due to its geographical location. Weather fickle, frequent storms. This area recorded the lowest temperature that can be set at sea: -45-50 °C. In summer, an area is formed over the water area high blood pressure, the air warms up from +2-+6 °C in the north and west to + 18-+20 °C on the coast. However, even in summer there may be snow.
The salinity of the sea near the coasts is about 34%o, which is associated with good mixing and uniform temperatures; in the inland areas the salinity increases to 35%o. At river mouths, especially when ice melts, salinity decreases sharply and the water becomes closer to fresh.
The circulation of water in the Kara Sea is complex, which is associated with the formation of cyclonic water cycles and the river flow of Siberian rivers. The tides are semidiurnal and their height does not exceed 80 cm.
The sea is covered with ice almost all year round. In some areas, multi-year ice is found, up to 4 m thick. Fast ice forms along the Zeregovaya line, the formation of which begins in September.

The Kara Sea contains predominantly Arctic ecosystems, however, during global warming accumulations of boreal and boreal-arctic species are noted. The greatest biodiversity is confined to upwelling zones, the edge of sea ice, river estuaries, areas of underwater hydrothermal fluids and the tops of the seafloor relief. Commercial concentrations of cod, flounder, black halibut, and whitefish have been recorded in the water area. Among the environmentally unfavorable factors leading to disruption of ecosystems, it should be noted pollution with heavy metals and petroleum products. Also in the water area there are sarcophagi of radioactive reactors, the burial of which was carried out in the second half of the 20th century.
Arctic omul is a semi-anadromous fish and an important commercial species. It spawns in the Yenisei River, and feeds in the coastal zone of the Kara Sea. According to one hypothesis, the omul could reach Lake Baikal, the cause of which is a glacier. Because of the glacier, the omul was unable to return to its “historical homeland”, giving rise to a branch of the Baikal omul.

Laptev sea

The Laptev Sea is a marginal sea of ​​the Arctic Ocean, located between the Taimyr Peninsula and the Severnaya Zemlya islands in the west and the New Siberian Islands in the east (Fig. 42). This is one of the deepest northern seas, the deepest great depth is 3385 m. The coast is heavily indented. The southern part of the sea is shallow with depths of up to 50 m, bottom sediments are represented by sand, silt with admixtures of pebbles and boulders. Northern part is a deep-sea basin, the bottom of which is covered with silt.
The Laptev Sea is one of the harshest seas in the Arctic Ocean. Climatic conditions are close to continental. In winter, the area of ​​high atmospheric pressure, which causes low air temperatures (-26-29 °C) and slight cloudiness. In summer, the area of ​​high pressure gives way to low pressure, and the air temperature increases, reaching its highest point in August at +1-+5 °C, but in enclosed spaces the temperature can reach higher values. For example, in Tiksi Bay a temperature of +32.5 °C was recorded.
Water salinity varies from 15%o in the south to 28%o in the north. Near the mouth areas, salinity does not exceed 10%. Salinity increases with depth, reaching 33%. Surface currents form a cyclonic gyre. Tides are semidiurnal, up to 0.5 m high.
The cold climate causes active development of ice in the water area, which can persist throughout the year. Hundreds of kilometers of shallow water are occupied by fast ice, and floating ice and icebergs are found in open waters.
The ecosystems of the Laptev Sea are not distinguished by species diversity, which is associated with extreme natural conditions. The ichthyofauna has only 37 species, and the bottom fauna is about 500. Fishing is developed mainly along the coasts and at river mouths. However, the Laptev Sea is of great transport importance. The port of Tiksi is of greatest importance. The ecological state of some areas of the sea is assessed as catastrophic. In coastal waters it is noted increased content phenol, petroleum products, organic matter. Most of pollution comes with river waters.

From time immemorial, the Laptev Sea has been the main “workshop” for ice production in the Arctic. International group Researchers within the Polynya project have been studying the climate in the water area for several years, as a result of which it was noted that since 2002, the water temperature has increased by 2 °C, which will inevitably affect its ecological condition.

East-Siberian Sea

The East Siberian Sea is a marginal sea of ​​the Arctic Ocean. It is located between the New Siberian Islands and Wrangel Island (see Fig. 42). The coasts are flat, slightly indented, and in some places there are sandy and silty dry areas. In the eastern part beyond the mouth of the Kolyma there are rocky cliffs. The sea is shallow, the greatest depth is 358 m. The northern border coincides with the edge of the continental shallows.
The bottom topography is leveled and has a slight slope from southwest to northeast. Two underwater trenches stand out in the relief, which are presumably former river valleys. The soil is represented by silt, pebbles, and boulders.
The proximity to the North Pole determines the severity of the climate, which should be classified as polar marine. It is also worth noting the influence on the climate of the Atlantic and Pacific oceans, from where cyclonic air masses come. The air temperature in January over the region is -28-30 °C, the weather is clear and calm. In summer, an area of ​​high pressure forms over the sea, and low pressure over the adjacent land, which leads to the emergence of strong winds, the speed of which is maximum towards the end of summer, when the western part of the water area turns into a zone of strong storms, while the temperature does not exceed +2-+3 °C . This section of the Northern sea ​​route During this period it becomes most dangerous.
The salinity of water near river mouths is no more than 5%o, increasing towards the northern outskirts to 30%o. With depth, salinity increases to 32%.
Even in summer the sea is not free of ice. They drift in a northwesterly direction, obeying the circulation of water masses. As the activity of the cyclonic gyre intensifies, ice penetrates into the water area from the northern borders. The tides in the East Siberian Sea are regular, semi-diurnal. They are most clearly expressed in the northwest and north, near southern shores The tide height is insignificant, up to 25 cm.

The combination of natural and climatic conditions influenced the formation of ecosystems in the East Siberian Sea. Biodiversity is much lower compared to other northern seas. In the estuary areas there are schools of white fish, polar cod, Arctic char, whitefish, and grayling. There are also marine mammals: walruses, seals, polar bears. Cold-loving brackish-water forms are common in the central parts.
East Siberian cod (ninefin) (Fig. 43) lives near the coast in brackish waters and enters river mouths. The biology of the species has hardly been studied. Spawning occurs in summer in warm coastal waters. It is an object of fishing.

Chukchi Sea

The Chukchi Sea is located between the Chukotka and Alaska peninsulas (Fig. 44). The Long Strait connects it with the East Siberian Sea, in the area of ​​Cape Barrow it borders on the Beaufort Sea, and the Bering Strait connects it with the Bering Sea. The International Date Line runs through the Chukchi Sea. More than 50% of the sea area is occupied by depths of up to 50 m. There are shallows with depths of up to 13 m. The bottom relief is complicated by two underwater canyons with depths from 90 to 160 m. The coast is characterized by slight ruggedness. The soils are represented by loose deposits of sand, silt, and gravel. The climate of the sea is greatly influenced by proximity North Pole and the Pacific Ocean. In summer, anticyclonic circulation occurs. The sea is characterized by high storm activity.

The circulation of water masses is determined by the interaction of cold Arctic and warm Pacific waters. A cold current runs along the Eurasian coast, carrier of water from the East Siberian Sea. The warm Alaskan Current enters the Chukchi Sea through the Bering Strait, heading towards the shores of the Alaska Peninsula. Tides are semidiurnal. The salinity of the sea varies from west to east from 28 to 32%. Salinity decreases near melting ice edges and river mouths.
The sea is covered with ice for most of the year. In the southern part of the sea, clearing of ice occurs during 2-3 warm months. However, floating ice brings it to the coast of Chukotka from the East Siberian Sea. The north is covered with multi-year ice more than 2 m thick.
The penetration of warm waters of the Pacific Ocean is the main reason for a slight increase in species diversity in the Chukchi Sea. Boreal species are joining the typical Arctic species. 946 species live here. There are navaga, grayling, char, and polar cod. The most common marine mammals are polar bears, walruses, and whales. The location at a sufficient distance from industrial centers determines the absence of serious changes in marine ecosystems. Affects the ecological picture of the water area Negative influence the flow of petroleum products along the Northern Sea Route, as well as waters containing aerosol materials coming from the coast of North America.
The Chukchi Sea serves as a connecting link between ports Far East, the mouths of Siberian rivers and the European part of Russia, as well as between the Pacific ports of Canada and the USA and the mouth of the Mackenzie River.

The Arctic Ocean, the smallest among the oceans, is connected to the Atlantic Ocean by the Davis, Danish and Faroe-Icelandic straits, and to the Pacific Ocean by the Bering Strait. The coastlines of the Arctic Ocean are diverse: the shores of the White, Barents, Kara and East Siberian seas are low and swampy; The coasts of Scandinavia and Greenland, indented by fjords, are high and rocky; the coasts of the islands of the Canadian Arctic Archipelago, which have a no less winding pattern, are also low.

In terms of the abundance of islands, the Arctic Ocean ranks second after the Pacific Ocean. Along the lines of the most large islands This ocean, Iceland and Greenland, draws the boundary separating the Arctic Ocean from the Atlantic. The Wrangel and Herald Islands, located on the border of the East Siberian and Chukchi Seas, form a conservation zone. Here is the only white goose nesting area in Russia, walrus rookeries are concentrated, and the steep cliffs bordering the islands are the site of bird colonies.

The average depth of the Arctic Ocean is only 1130 m, the maximum is 5449 m. Distinctive feature The bottom relief of the Arctic Ocean is a large continental shoal, or shelf, making up more than a third of the total ocean area. Its width reaches 1300-1500 km. Most of the seas of the Arctic Ocean lie on the shelf - the Barents, Greenland, Kara, Laptev, Norwegian, East Siberian, Chukotka. In contrast, the White Sea and Hudson Bay of the Arctic Ocean are inland seas with only a narrow outlet to the main ocean. The Arctic seas are characterized by significant fluctuations in tides; The tides reach significant heights, especially in the Mezen Bay of the White Sea, where during high tide the water reaches the ten-meter mark.

The structure of the Arctic Ocean floor

The Arctic Ocean is usually divided into three so-called basins. First of all, the Arctic basin, covering the entire vast water area around the North Pole. The continental slope of the Barents Sea separates this basin from the North European; the border between them and the Atlantic Ocean is drawn along the parallel of 80 degrees north latitude in the segment between the islands of Greenland and Spitsbergen. The Arctic Ocean also includes the straits of the Canadian Arctic Archipelago, the Baffin Sea and Hudson Bay; this entire area is called the Canadian Basin.

Canadian Basin

Most of it consists of the straits of the archipelago of the same name. The topography of their bottom is characterized by large depths for straits: measurements of the bottom in most straits of the archipelago showed values ​​exceeding 500 m. In addition to this feature, the archipelago is notable for the complex, bizarre outlines of the islands and straits. From the point of view of scientists, this indicates a relatively recent glaciation. Many islands of the Canadian archipelago are partially or completely covered by glaciers.

Glacial relief is also characteristic of the bottom of Hudson Bay, which crashed into the Canadian coast of North America. However, unlike the straits of the Canadian archipelago, the bay is shallow. The Baffin Sea has greater depth; the maximum elevation shown by measurements is 2414 m. The Baffin Sea occupies a vast basin, limited by a wide shelf and a clearly defined continental slope; These features are generally characteristic of the bottom topography of the Arctic Ocean. Most of the Baffin Sea shelf lies at considerable depth - from 200 to 500 m.

North European Basin

The basis of the bottom of the North European basin is formed by a system of underwater mountain ranges. Researchers consider it a continuation of the Mid-Atlantic underwater ridge. The Reykjanes Ridge, part of this system, is located in the zone of ancient faults caused by constant movement plates of the earth's crust - rifts; this area is called the “Icelandic rift zone” because it begins a little south of this island, continuing from there to the northeast and then north. It's quite high here seismic activity, hot springs are common on the islands.

The Kolbeinsey ridge looks like a continuation of this zone; the Jan Mayen fault line crosses it almost exactly along the 72nd parallel. This strip is associated with increased volcanic activity and - in the relatively recent past - the formation of an island bearing the same name as the entire area: Jan Mayen. Even further north, a little away from the main mass of mountain structures, there is a small ridge named after the Norwegian meteorologist Henrik Mohn. This underwater mountainous area was once impacted by a series of eruptions, which caused a fairly noticeable displacement of some of its structures. Up to the 74th parallel, the ridge goes northeast, and then abruptly changes direction to the meridional. This is the link mountain system is called the Knipovich Ridge. West Side the ridge is a monolithic ridge, the eastern one has a noticeably lower height and practically merges with continental foot, under the sedimentary deposits of which it is almost buried.

From the island of Jan Mayen to the south stretches the Jan Mayen Ridge, reaching almost to the Faroe-Iceland threshold, which is often considered a section of the border with the Atlantic. This ridge is most credited ancient origin throughout the entire bottom system of the North European Basin. Between this ridge and the Kolbeinsen Ridge there is a relatively (by oceanic standards) shallow - up to 2 thousand m - basin. Its bottom is composed of basalts - traces of previous fissure eruptions. Thanks to basalts, this section of the bottom, called the Icelandic Plateau, is leveled and elevated compared to the ocean floor adjacent to the east.

Far to the west stands the Voring Plateau, an underwater extension of the Scandinavian Peninsula. This plateau divides the eastern part of the North European Basin, usually called the Norwegian Sea, into two basins - the Norwegian and Lofoten. These basins are deeper, their maximum depths are 3970 and 3717 m, respectively. The bottom of the Norwegian Basin is hilly, almost in two it is divided by a chain of low mountains stretching from the Faroe Islands to the Voring Plateau - the Norwegian Range. Almost half of the bottom of the Lofoten Basin is occupied by a flat plain, the top layer of which is composed of petrified silt. On the western edge of the North European Basin is the Greenland Basin, the maximum depth of which is also the maximum depth of the entire ocean.

Arctic Basin

However, the main part of the Arctic Ocean is still the Arctic Basin. In area it is 4 times larger than North European. More than half of the bottom of the Arctic basin is a continental shelf, especially extensive along the Eurasian coast.

On the outskirts of the Barents Sea, the ocean floor is formed by ancient folded formations resembling mountains. These folds of the earth's crust have different ages: off the Kola Peninsula and northeast of the island of Spitsbergen they are billions of years old, and off the coast of Novaya Zemlya they are no more than 30 million years old. Among the depressions and troughs of the Barents Sea bottom, it is worth noting the Medvezhinsky Trench in the west of the sea, the St. Anna and Franz Victoria trenches in the north, as well as the Samoilov Trench located almost in the center. Between them rise the Medvezhinskoye Plateau, the Central Plateau, the Perseus Hill and some others. By the way, the well-known White Sea, in fact, is nothing more than a bay of the Barents Sea jutting deep into the land.

The geological structure of the Kara Sea shelf is heterogeneous. Its southern part is mainly a continuation of the relatively young West Siberian Plate. In the northern part, the shelf is crossed by a layer of low folds of the earth's crust - a submerged link of an ancient ridge, smoothed by time, which stretches from the northern tip of the Urals to Novaya Zemlya. Its structures continue in northern Taimyr and in the Severnaya Zemlya archipelago. A noticeable proportion of the Kara Sea bottom surface falls on the Novaya Zemlya Trench with a maximum depth of 433 m; the Voronin Trench is located in the north. Unlike the Barents Sea, most of the shelf within the Kara Sea has “normal” depths for this type of bottom - no more than 200 m. Extensive shallow water with depths of less than 50 m adjoins the southeastern coast of the Kara Sea. The bottom of the Kara Sea is crossed by clearly defined flooded extensions of the Ob and Yenisei valleys; the latter receives a number of “tributaries” coming from the Central Kara Seamount. The effects of glaciation are still clearly visible in the bottom topography near Novaya Zemlya, Severnaya Zemlya and Taimyr.

In the bottom relief of the Laptev Sea, the predominant type of relief is a leveled plain. This leveled relief continues on the bottom of the East Siberian Sea; in some places on the bottom of the sea near the New Siberian Islands, as well as to the north-west of the Bear Islands, a ridge topography is clearly visible, probably formed as a result of the natural preparation of outcrops of hard rocks, which were subsequently shrouded in sediment. The shelf stretching along the northern coast of Alaska is relatively narrow and is a plain leveled largely by temperature fluctuations due to nearby underwater eruptions. At the northern edges of the Canadian archipelago and Greenland, the shelf again becomes overdeepened, and signs of glacial relief again appear.

The submarine margins of North America, Greenland and Eurasia surround on all sides the leveled part of the Arctic Basin, which is occupied by the mid-ocean Gakkel Ridge and the ocean floor. The Gakkel Ridge begins from the valley with rocks typical of the oceanic Lena - a narrow depression, the origin of which is associated with the Spitsbergen fault zone, limiting the Knipovich Ridge from the north. Further, the Gakkel Ridge extends parallel to the Eurasian submarine margin and adjoins the continental slope in the Laptev Sea in the area where the ridge intersects the 80th parallel. The Gakkel Ridge is narrow; it consists mainly of a well-defined fault zone and is intersected a large number oceanic glacial depressions parallel to each other. Some of them have depths of more than 4 thousand m - this is a very large depth for the Arctic Ocean, if we remember that the maximum depth of this ocean is 5527 m. Numerous earthquake epicenters are located along the fault zone associated with the Gakkel Ridge. There are some indications of manifestations of underwater volcanism.

Another major orographic structure of the Arctic basin is the Lomonosov Rise. Unlike the Gakkel Ridge, this is a monolithic mountain structure, stretching in the form of a continuous shaft from the underwater margin of northern Greenland to the continental slope of the Laptev Sea, north of the New Siberian Islands. The Lomonosov Rise is believed to contain a continental-type crust.

Another rise - the Mendeleev rise - stretches from the underwater edge of Wrangel Island to Ellesmere Island in the Canadian archipelago. It has a blocky structure and, in all likelihood, is composed of rocks typical of the marine crust. It is also worth mentioning two marginal plateaus - the Ermak plateau located north of Spitsbergen and the Chukotka plateau north of the Chukchi Sea. Both of them are educated earth's crust continental type.

Ridges and uplifts divide the flat part of the Arctic basin into a number of basins. Between the underwater margin of Eurasia and the Gakkel Ridge lies the Nansen Basin with a hilly bottom and a maximum depth of 3975 m. Between the Gakkel Ridge and the Lomonosov Rise is the Amundsen Basin. The bottom of the basin is a vast flat plain. The North Pole is located in this basin. Here in 1938 the expedition of I.D. Papanina measured the depth: 4485 m - the maximum depth of the Amundsen Basin. The Makarov Basin is located between the Lomonosov and Mendeleev uplifts.

Its maximum depth is more than 4510 m. The southern, relatively shallow part of the basin with a maximum depth of 2793 m is considered a separate Podvodnikov basin. The largest in area, the Canadian Basin is located south of the Mendeleev Rise and east of the Chukchi Plateau. Its maximum depth is 3909 m, and its bottom is occupied mainly by a flat plain, with which the inclined accumulative plain of the continental foot gradually merges.

Ice and currents

From the west, warm waters of the North Atlantic Current enter the Arctic seas. This stream, which is driven by westerly winds along the coast of Eurasia, is noticeably different from the surrounding Arctic waters: the salinity and density of its waters are higher. As a result, the warm waters of one of the branches of the North Atlantic Current - the North Cape Current - sink deeper when moving east in the Kara and Barents Seas. Colder arctic currents remain on the ocean surface while Atlantic waters slow underwater currents are transported far to the east, reaching the East Siberian Sea. Along with this, a cold countercurrent moves from the Bering Strait to Greenland from east to west across all seas.

The average thickness of Arctic sea ice is 2 m, which is significantly higher than the same parameters of Antarctic ice. In autumn, off the coast of the Arctic seas, relatively thin, motionless ice firmly adhered to the shore - coastal fast ice - forms. Behind its strip, in the open sea, one can see perennial drifting ice, which, when colliding, forms disorderly piles - hummocks; their height reaches 20 m. In addition to sea ice in high seas northern latitudes There are also fragments of continental ice - icebergs. They originate from glaciers sliding down the shores of Severnaya Zemlya and Franz Josef Land. Arctic icebergs are relatively small and smaller in size than Antarctic icebergs.

The formation of sea ice is not an instantaneous process. At air temperatures from minus 1.6 °C to plus 2.5 °C, crystals begin to grow on the surface of the water. In calm weather, fog rises over the water, about which sailors say: “The sea soars.” The crystals grow by connecting with each other and form clumps, which over time begin to resemble a mess of snow and ice; This porridge is called “snezhura”. The sea seems to be covered with a layer of snow, which, depending on the lighting, appears either steel-gray or lead-gray in color and resembles freezing liquid grease; this is the so-called “ice lard”. As the cold intensifies, this porridge freezes, and the spaces of still water are covered with a thin crust of ice. Of course, freezing cannot be uniform. Ice disks with raised edges, with a diameter of several centimeters to 3-4 m and a thickness of up to 10 cm, appear from ice fat and snow slush. Such ice is called pancake ice. When the wind blows and the sea is rough, the ice fat gathers into whitish lumps - this is loose ice.

The Arctic Ocean is the smallest ocean on Earth in terms of area and depth, located entirely in the northern hemisphere, between Eurasia and North America. It is adjacent to the territories of Denmark (Greenland), Iceland, Canada, Norway, Russia and the United States of America. The seas of the Arctic Ocean are marginal and internal, and together with bays and straits they occupy 10.28 million square meters. km.

Seas of the Arctic Ocean

The list of bodies of water belonging to the Arctic Ocean consists of ten seas, six of which wash the shores of the Russian Federation.

• Norwegian. It washes the shores of Iceland and the Scandinavian Peninsula.
• Greenlandic. Located between the eastern coast of Greenland and the western border of Iceland.
• Barentsevo. A sea located in the western part of Russia.
• White. Northern coast of Europe.
• East Siberian. It washes the shores of Russia, located among the Novosibirsk and Wrangel Islands.
• Karskoye. Eastern border The sea runs along the Severnaya Zemlya archipelago, and the western one borders the coastline large quantities islands, including Novaya Zemlya.
• Baffin. It runs along the western border of the island of Greenland, and on the other side washes the shores of the Arctic Canadian archipelago.
• Laptev. It washes the shores of Taimyr, the New Siberian Islands and Severnaya Zemlya.
• Beaufort. The coastline of the North American continent, from Cape Barrow to the Canadian Arctic Archipelago.
• Chukotka. It washes the shores of two continents: Eurasia and North America.

Rice. 1. Location of the seas of the Arctic Ocean

The largest area is considered to be the Barents Sea, which is located in the western part of the Eurasian continent. In comparison with other seas of the Arctic Ocean, the Greenland Sea is recognized as the deepest, whose depths reach about 5500 m.

Rice. 2. The Barents Sea is the largest in the Arctic Ocean

The warmest and most non-freezing is the Norwegian Sea, since its warm current prevents the water from freezing even in winter.

The seas of the Arctic Ocean washing Russia

The northern seas of Russia consist of five marginal seas and one internal one.

• Barencevo sea- marginal sea of ​​the Arctic Ocean. It washes the shores of Russia and Norway. The sea is located on the continental shelf and is of great importance for transport and fishing; a large Russian port, Murmansk, is located here.

The southeastern part of the Barents Sea, bounded by the islands of Vaygach and Kolguev, is called the Pechora Sea - it is the shallowest. Its average depth is only 6 m.

• Chukchi Sea- a marginal sea, located between Chukotka and Alaska. In the west, the Long Strait connects with the East Siberian Sea, in the east, in the area of ​​Cape Barrow, it connects with the Beaufort Sea, in the south, the Bering Strait connects it with the Bering Sea of ​​the Pacific Ocean. The international date line runs through the sea. Fishing and slaughter of sea animals are poorly developed.
• White Sea The Arctic Ocean is internal, located in the north of the European part of Russia. Its salinity is very low, which is due to its connection with several freshwater rivers. The White Sea is the smallest sea in the Arctic Ocean, washing the shores of Russia.
• Laptev sea- a marginal sea, located between the northern coast of Siberia in the south, the Taimyr Peninsula, the Severnaya Zemlya islands in the west and the New Siberian Islands in the east. It has a harsh climate, poor nature and a small population on the coast. Most of the time, with the exception of August and September, it is under ice.

Rice. 3. The Laptev Sea is almost always covered with ice

• East-Siberian Sea— the marginal sea is located between the New Siberian Islands and Wrangel Island. The sea is connected through straits to the Chukchi Sea and the Laptev Sea. The sea is covered with ice almost all year round. In the eastern part of the sea, floating multi-year ice remains even in summer.
• Kara Sea- a marginal sea in the Arctic Ocean basin. This is one of the coldest seas in Russia; only near the river mouths the water temperature in summer is above 0 °C. Fogs and storms are frequent. Most of the year the sea is covered with ice.

The report “The Arctic Ocean” for children will briefly tell you a lot useful information about the smallest ocean on the planet. Also a message about North Arctic Ocean can be used while preparing for class.

Message about the Arctic Ocean

The Arctic Ocean is smallest ocean planets. Although in terms of the number of islands in it, it is only ahead of Pacific Ocean. The largest islands are the Canadian Arctic Archipelago, Greenland, Novaya Zemlya, Spitsbergen. The Arctic Ocean occupied the territory of the North Pole. It is characterized by a large number river flow, so the ocean has low salinity. Most of the ocean is continental shelf.

Origin of the Arctic Ocean

The ocean area began to form back in the Cretaceous period, when the division of one side of Europe and North America and the partial convergence of Asia and America took place. At the same time, lines of large peninsulas and islands were formed, and the water space was divided. Thus, the basin separated from the Pacific Basin Northern Ocean. Then the ocean grew, the continents rose, but the movement of lithospheric plates continues today.

The first information about the ocean dates back to the 4th century BC. when the Greek Pytheas described his journey to the island of Thule (presumably modern Iceland). From the 5th century, regular information about him began to arrive. It was identified as a separate ocean in the 17th century, giving it the name “Hyperborean Ocean”. Other ocean names include Tartarian, Arctic Sea, Northern, Scythian, and Arctic.

Relief of the bottom of the Arctic Ocean

The ocean is located on the Eurasian and North American lithospheric plates. Most of the bottom is occupied by the shelf. It accounts for a third of the ocean's area. In the central part there are the Amundsen and Nansen basins, the Lomonosov and Mendeleev ridges, and deep-sea faults.

Climate of the Arctic Ocean

The Arctic Ocean is located in the subarctic and arctic zones, which determine its climate. Arctic air masses are observed throughout the year, although they are much softer and warmer than in Antarctica. The warm North Atlantic Current, penetrating from the south and making winters milder and summers less dry, has a particular influence on the climate. The subpolar regions are under ice. IN Lately ice cover is decreasing. The air temperature ranges from -20 0 C to -40 0 C degrees.

Minerals of the Arctic Ocean

Deposits of heavy metals were found in the bottom sediments of the shelf zone. The mineral resources of the ocean are still poorly studied. Recently, oil and gas fields began to be exploited on the shelf.

Arctic Ocean: organic world

Until the twentieth century, the Arctic Ocean was considered a dead zone, as research was not carried out due to the harsh conditions. The cold areas of the Arctic Ocean are favored by beluga whales, polar bears, narwhal walruses, and seals. In warmer areas, the animal world is diverse due to a large number of fish - cod, herring, sea bass. Also here you can meet the bowhead whale, which is on the verge of extinction. It is worth noting that the fauna of the Arctic Ocean differs from other oceans in its gigantism. A giant cyanide jellyfish, giant mussels, and a sea spider swim in the waters.

The ocean flora is very sparse, since the ice does not allow the sun's rays to pass through. Mostly only unpretentious algae grow here.

Arctic Ocean: interesting facts

• In the West, the ocean was first called the Hyperborean Sea, and in Russia the Sea-Ocean or the Breathing Sea.
• Animals and birds that live in the ocean have white skin or white feathers.
• It is known that the world famous ship Titanic sank in the Atlantic after a collision with an iceberg that sailed from the Arctic Ocean.
• An unusual phenomenon can be observed in the ocean - Effect " dead water» . A sailing ship can suddenly stop, although its engines continue to work like clockwork. The whole point lies in the boundary of water layers, which have different densities. This creates internal waves that slow down the ship.
• Near the coast there is pack ice, which moves due to tides and pressure.

We hope that the message about the Arctic Ocean helped you prepare for the lesson. A short story You can add information about the Arctic Ocean using the comment form below.