East-Siberian Sea. Depth, islands, resources and problems of the East Siberian Sea. East Siberian Sea: description, resources and problems

Already from the name of this natural reservoir it is clear that it is located in the region of the northern coast Eastern Siberia. The boundaries of the sea are mainly represented by imaginary lines. Only in some parts it is limited to dry land. Previously, until the beginning of the 20th century, the sea had several names, including Indigirskoye and Kolyma. Now it is called East Siberian.

After reading the article, you can learn more detailed information about this body of water: characteristics, climatic conditions. Resources are also listed here. East Siberian Sea and current problems.

Location

The entire sea is located beyond the Arctic Circle. Its southernmost point is located off the coast of the Chaun Bay. All its shores belong to the territory of Russia. The sea is located in the North Arctic Ocean. This is a place where the effect of warm waters is almost not felt. Atlantic Ocean, and the waters of the Pacific still do not reach it.

The East Siberian Sea is marginal. There are the New Siberian Islands (border with the Laptev Sea), Ayon, Medvezhiy and Shalaurova. The sea itself is located between the Novosibirsk Islands and Wrangel Island. It is connected by straits with the Chukchi and Laptev Seas.

Description and characteristics

In the central and western parts of the coast are sloping, and two lowlands adjoin the coast: Nizhne-Kolymskaya and Yano-Indigirskaya. Spurs approach the coast of the eastern part (east of the mouth of the Kolyma) Chukchi highlands. In places, rocky cliffs also formed here. On Wrangel Island, on its western coast, they reach up to 400 meters in height. In the section of the New Siberian Islands, the coastline is monotonous and low-lying. The sea bed is formed by a shelf, whose relief is mostly flat, and it is inclined slightly in a northeasterly direction.

More deep places characteristic of the eastern region. The sea here has a depth of up to 54 meters, in the central and western parts - up to 20 meters, and in the northern regions - up to 200 meters (isobath - the boundary of the sea). The greatest depth of the East Siberian Sea is about 915 meters, and the average is 54 meters. In other words, this body of water is completely within the continental shelf.

The water surface area is 944,600 sq. km. The waters of the sea communicate with the waters of the Arctic Ocean, in connection with this, the reservoir belongs to the type of marginal continental seas. The volume is approximately 49 thousand cubic meters. km. Practically all year round the air temperature is below zero, so the waters of the sea are always covered with drifting large ice floes several meters thick.

Salinity

The East Siberian Sea in the eastern and western parts has different meanings salinity. Due to the river runoff in the eastern part, the salt concentration decreases. This figure here is about 10-15 ppm. At the confluence with the sea major rivers salinity almost disappears. Closer to the ice fields, the concentration increases to 30 units. There is also an increase in salinity with depth, where it can reach 32 ppm.

Relief

The coast line has large bends. In this regard, the sea in places pushes the boundaries of the land deep into the mainland, and in places, on the contrary, the land protrudes far into the sea. There are also areas with an almost flat coastline. Small meanders are mainly observed at the mouths of rivers.

The east and west coasts have very different topography. The coast, washed by the sea from the mouth of the Kolyma to the New Siberian Islands, has an almost monotonous landscape. The reservoir in these places borders on swampy tundra. The coast here is flat and low.

A more varied landscape is noted on the coast formed by east of the river Kalymy, but mountains prevail here. The sea to the island of Aion is bordered by small hills, some of which have rather steep slopes. The region of Chaun Bay is characterized by low steep banks.

A large area of the sea floor is covered with a small sedimentary cover. Islands in the East Siberian Sea are not numerous. Most of of which is formed at the expense of the foundation. Based on the results of studies (aeromagnetic surveys), it was determined that the composition of the shelf sediments mainly includes sandy silt, pebbles and crushed boulders. There are suggestions that some of them are fragments of islands. They are scattered throughout the ice. To a greater extent, due to the predominance of flat relief, the depth of the East Siberian Sea is only 20-25 meters.

Hydrology

Almost the whole year the reservoir is covered with ice. In the eastern areas, even in summer, you can see perennial floating ice. They are driven away from the coast by continental winds to the north. Ice drifts in a northwesterly direction due to the circulation of water, which is affected by anticyclones near the North Pole.

The area of the cyclonic circulation increases, and perennial ice floes from the polar latitudes enter the sea after the weakening of the anticyclone. To date, the system of currents in this reservoir has not been fully studied. But it can be stated with confidence that the water circulation of these places is characterized by a cyclonic character.

This reservoir, in comparison with other representatives of the Arctic Ocean basin, is characterized by not very high river flow. The rivers of the East Siberian Sea are not numerous. The largest river flowing into the sea is the Kolyma. Its stock is approximately 132 cubic meters. km per year. The second in terms of the same characteristic is the Indigirka River, which brings in half the volume of water over the same period. All this has little effect on the general hydrological situation.

The average annual precipitation is from 100 to 200 mm. Due to the absence of trenches in the sea with great depths and due to the fact that large area represented by shallow waters, surface waters occupy vast spaces.

Climate

In winter, the East Siberian Sea is under the influence of south and southwest winds. Their speed is about 7 meters per second. also in winter time on the climate of the sea big influence renders the Siberian maximum. Pacific cyclones, prevailing in the southeastern parts of the sea, bring snowstorms, strong winds and rather cloudy weather with constantly drizzling rain or sleet.

Flora and fauna

The fauna and flora of the East Siberian Sea is similar to that of the neighboring Laptev Sea, as both are typically arctic. The same mammals and birds, the same fish as in many other northern seas. Seals, narwhals live here, sea hares and walruses. Polar bears settled on the islands. These places are also favored by a huge number of nesting birds. You can meet here geese: white-fronted and goose. There is also a comb eider and a rather rare black goose. Large bird colonies gather: kittiwakes, gulls, guillemots.

Prey sea animal and fishing in coastal waters are engaged only locals. It should be noted that large shoals of white fish can be found here in the areas of river mouths. Phytoplankton of the sea is represented by blue-green and diatoms. Sometimes pteropods and tunicates appear. The soil abounds with polychaetes, amphipod crustaceans and isopods. Representatives of mammals are beluga whales, seals, walruses and cetaceans (especially minke whales).

The resources of the East Siberian Sea in terms of flora and fauna are relatively poor. This is primarily due to the rather harsh climate conditions. Only the most frost-resistant representatives took root in these places.

Concluding on the problems

The problems of the East Siberian Sea are similar to the problems of most northern seas. For several years, the biological resources of the region, especially whales, have been destroyed. To date, this has led to a significant reduction in the number of these mammals, as well as the extinction of some species.

Problem global character- melting glaciers, which adversely affects the local fauna. Mention should also be made of the results human activity(development of hydrocarbon deposits), which adversely affected the state of the reservoir.

EAST SIBERIAN SEA, a marginal sea of the Arctic Ocean off the northeastern coast of Asia, between the New Siberian Islands and Wrangel Island. In the west it borders on the Laptev Sea, connecting with it by the straits: Dmitry Laptev, Eterikan and Sannikov, in the east - with the Chukchi Sea, which is connected to the Long Strait. The northern boundary runs along the edge of the continental shelf, approximately along the 200 m isobath (79° north latitude). The area is 913 thousand km 2, the volume is 49 thousand km 3. The greatest depth is 915 m.

The coastline is relatively indented. Bays: Chaun Bay, Kolyma Bay, Omulyakhskaya and Khromskaya Bays. Islands: Novosibirsk, Bear, Aion and Shalaurova. Some islands are entirely composed of fossil ice and sand and are subject to intense destruction. Large rivers flow into the sea: Kolyma, Alazeya, Indigirka, Khroma. The coast of the western part of the sea (up to the Kolyma River) is low-lying and is composed of permafrost alluvial-marine deposits of the Quaternary age, including lenses of fossil ice. East Coast(from the Kolyma River to the Long Strait) mountainous, steep in places, composed of bedrock; denudation type of shores is developed here.

Relief and geological structure of the bottom. The East Siberian Sea is located mainly within the shelf, 72% of its bottom area has depths of up to 50 m. The shelf is located within the North American lithospheric plate. The underwater relief of the shelf, which forms the bed of the sea, is a plain, slightly inclined from the southwest to the northeast. The bottom of the western part of the sea is a flat shallow plain, here is the Novosibirsk shoal. In the southern part, shallow trenches are noted - traces of ancient river valleys of pre-glacial and glacial times. The greatest depths are in the northeastern part. The sea floor is composed of folded complexes (Mesozoic in the south and possibly older in the north), dissected by Late Mesozoic rift structures and overlain by a thin cover of Cenozoic sediments. Modern bottom sediments consist mainly of sandy silt containing crushed boulders and pebbles brought by ice.

Climate. The climate of the East Siberian Sea is arctic. In winter, under the influence of the Siberian High, cold southwestern and southern winds prevail over the sea. Average air temperatures in February are from -28 to -30 °С (minimum -50 °С); in July in the southern part from 3 to 7 °С, in the northern part - from 0 to 2 °С. In summer, the weather over the East Siberian Sea is predominantly overcast with light drizzling rain, sometimes sleet; northerly winds prevail. In autumn, on the coast, the speed of northwestern and northeastern winds increases to 20-25 m/s; at a distance from the coast, the force of storm winds reaches 40-45 m/s, and foehns contribute to the strengthening of the wind. 100-200 mm of precipitation falls annually.

Hydrological regime. The continental flow into the East Siberian Sea is relatively small and amounts to about 250 km 3 /year, of which the flow of the Kolyma is 123 km 3 /year, and the flow of Indigirka is 58.3 km 3 /year. All river runoff goes to southern part sea, 90% - in the summer. The main part of the East Siberian Sea is occupied by surface Arctic waters. In the estuarine areas, waters formed as a result of the mixing of river and sea water. In winter, near the mouths of rivers, the temperature surface water varies from -0.2 to -0.6 °С, and at the northern border of the sea from -1.7 to -1.8 °С. In summer, the temperature distribution of surface waters is determined by the ice conditions. In bays and bays it is 7-8 °С, in ice-free areas it is 2-3 °С, and near the ice edge it is about 0 °С. The salinity of surface waters increases from southwest to northeast from 10-15‰ near river mouths to 30-32‰ at the ice edge. Most of the year the East Siberian Sea is covered with ice. In the eastern part, floating ice remains offshore even in summer. Feature ice - the development of fast ice, which is most widely distributed in the western shallow part of the sea, where its width reaches 600-700 km; in the central regions - 250-300 km, to the east of Cape Shelagsky it occupies a narrow coastal strip of 30-40 km. By the end of summer, the thickness of the fast ice is 2 m. Behind the fast ice there are drifting ice - one-year and two-year, 2-3 m thick; ice drift depends on circulation air masses. In the north, there is multi-year arctic ice. In the western part of the sea, between fast ice and drifting ice, there is a perennial polynya, along which the Northern sea route. The existence of a polynya in winter is associated with squeezing winds and tidal currents. In the eastern part, fast ice merges with drifting ice and the polynya closes. Currents form a cyclonic cycle; in the northern part, the current is directed to the west, in the southern - to the east. The tides are regular semidiurnal, the amplitude of level fluctuations is up to 25 cm.

Research History. The beginning of the development of the East Siberian Sea by Russian sailors dates back to the 17th century, when sailings were made along the coast between the mouths of the rivers. In 1648, S. Dezhnev and F. Popov sailed from the Kolyma River to the Bering Strait and to the Anadyr River. In the 18th century, the first works on the description of the coast and islands of the East Siberian Sea were made, maps were compiled. Particularly significant work was done by members of the Great Northern Expedition (1733-43). The contours of the coast were refined by the Ust-Yana and Kolyma expeditions led by P.F. Anzhu (1822) and F.P. Wrangel (1820-24), islands in the East Siberian Sea are named after them. In the 20th century, maps were refined by K. A. Vollosovich (1909) and G. Ya. Sedov (1909), as well as during the work of a hydrographic expedition in the Arctic Ocean (1911-14). After 1932, when the Sibiryakov icebreaker passed through the Northern Sea Route in one navigation, regular flights courts.

Economic use. The coastal zone is characterized as an area with weak economic activity. vegetable and animal world The East Siberian Sea is poor due to severe ice conditions. But in the areas adjacent to the mouths of the rivers, there are omul, whitefish, grayling, polar smelt, navaga, polar cod and flounder, salmon - char and nelma. Of the mammals, there are walrus, seals, polar bear; birds - guillemots, gulls, cormorants. Fishing is of local importance. The Northern Sea Route passes through the East Siberian Sea; the main port of Pevek (Chaun Bay). The East Siberian Sea is a promising oil and gas region, the development of which is difficult due to harsh natural conditions.

Ecological state. In general, the ecological situation in the East Siberian Sea is characterized as favorable due to the weak economic use this area. The shallow water shelf is slightly polluted, influenced river runoff, and as a result of thermal erosion of the banks, greenhouse gases (carbon dioxide and methane) enter the atmosphere.

Lit .: Zalogin B. S., Kosarev A. N. Sea. M., 1999.

November 26, 2006

1. ARCTIC OCEAN…………………………………………….3

2. EAST SIBERIAN SEA………………………………………………4

2.1. Shores………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

2.2. Bottom structure…………………………………………………………………………6

2.3. Characteristic climate……………………………………………………………7

2.4. Hydrological regime……………………………………………………..9

2.5. Ice regime………………………………………………………………13

2.6. Biology…………………………………………………………………………14

REFERENCES…………………………………………………………….15

1. THE ARCTIC OCEAN.

The Arctic Ocean is small compared to other parts of the World Ocean: its area is about 13.1 million km 2 (3.6% of the area of the World Ocean). However, practical and scientific significance research of the Arctic Ocean is very large. The shortest, but also one of the most difficult sea route in terms of ice conditions, runs through it. In addition, it serves as the only sea route to supply the booming industry of Siberia.

Due to its remoteness, harsh climate, and permanent ice cover, the Arctic Ocean has proven to be the least explored of the oceans. By the end of the 19th century almost all of its coastline was mapped in some detail, but most of the ocean itself remained unexplored. The northern tip of Greenland and the group of islands in the Canadian Arctic Archipelago were completely unexplored. Geographers did not have a single point of view regarding the distribution of land and sea. Some scientists, including the German geographer Petermann, believed that Greenland stretched across North Pole to Wrangel Land (now Wrangel Island); others believed that the central polar region was composed of numerous islands separated by shallow areas.

During the expedition on the ship Jeannette (1879-1881) it was found that Fr. Wrangel is not adjacent to Greenland. In 1893-1896. Nansen's ship "Fram" drifted with multi-year ice through the Arctic Basin (A. b.) from the Novosibirsk Islands to Svalbard. Analysis of the data of eleven measurements of the depths made during this drift showed that the depth of A. b. in this area varies from 3400 to 4000 m. So for the first time it was established that at least part of A. b. occupies a deep basin.

The Arctic Ocean is also interesting from a hydrometeorological point of view. In the North European Basin, there is the most powerful center on Earth of "isoanomalous overheating" of the atmosphere due to the heat of the ocean, the influence of which on atmospheric processes and climatic conditions manifests itself right up to Lake Baikal. The Arctic Ocean, especially its Arctic Basin, plays the role of one of the planetary "sinks" of heat both in the atmosphere and in the ocean.

2. EAST SIBERIAN SEA

The East Siberian Sea is located between the New Siberian Islands and about. Wrangel. Its western border is the eastern border of the Laptev Sea, it runs from the point of intersection of the meridian of the northern tip of about. Boiler house with the edge of the continental shoal (79°N, 139°E) to the northern tip of this island (Cape Anisii), then along the eastern shores of the New Siberian Islands to Cape Svyatoy Nos (Dmitry Laptev Strait). The northern boundary runs along the edge of the continental shelf from the point with coordinates 79°N. sh., 139 ° in. to the point with coordinates 76° N. latitude, 180° east etc., and the eastern border - from the point with these coordinates along the meridian 180 ° to about. Wrangel, then along its northwestern coast to Cape Blossom and further to Cape Yakan on the mainland. The southern border runs along the mainland coast from Cape Yakan to Cape Svyatoy Nos.

The East Siberian Sea belongs to the type of continental marginal seas. Its area is 913 thousand km 2, volume - 49 thousand km 3, average depth - 54 m, maximum depth - 915 m, i.e. this sea lies entirely on the continental shelf.

2.1. Shores.

The coastline of the East Siberian Sea forms rather large bends, in some places going into the land, in some places protruding into the sea, but there are also areas with a flat coastline. Small meanders are usually confined to the mouths of small rivers.

The landscapes of the western part of the coast of the East Siberian Sea differ sharply from the eastern part. In the section from the New Siberian Islands to the mouth of the Kolyma, the coasts are very low and monotonous. Here the swampy tundra approaches the sea. To the east of the mouth of the Kolyma, beyond Cape Bolshoy Baranov, the coast becomes mountainous. From the mouth of the Kolyma to about. Aion directly to the water approach low hills, abruptly breaking off in some places. The Chaun Bay is framed by low, but steep, even banks. The coastline of the sea differs in relief and structure on different areas belongs to different morphological types of coasts.

Suspended precipitation carried by rivers causes a change in depths in coastal areas and the formation of bars in the mouths of rivers. The Indigirka River carries out 16.7 million tons of suspended sediments per year, the Kolyma - 8.3 million tons. The liquid runoff of the Kolyma is 132 * 10 3 m 3 / year.

As a result of the warming effect of river waters on the adjacent coastal areas, intense thermal abrasion of the estuarine sections of the coast occurs. According to available data, the rate of abrasion ranges from 1-5 to 10-15m/year.

Where the coast is composed of bedrock (the region of Cape Baranov and Cape Shelagsky, the western coast of Wrangel Island, etc.), a denudation type of coast is usually developed, since the impact of waves is weakened and physical weathering processes predominate. Accumulative shores with wide sand and pebble bars separating chains of lagoons are found on the southern coast of the Long Strait.

2.2. Bottom structure.

The underwater relief of the shelf that forms the bed of the sea, in in general terms is a plain, very slightly inclined from the southwest to the northeast. The bottom of the sea has no noticeable depressions and hills. Depths up to 20-25 m predominate. The area of shallow depths in the western part of the sea forms the Novosibirsk shoal. The greatest depths are concentrated in the northeastern part of the sea. A noticeable increase in depth occurs in the horizon from 100 to 200 m.

Most of the sea floor is covered with a thin sedimentary cover. In the Tertiary period and at the beginning of the Quaternary, the bottom surface was an almost flat plain, composed of ancient alluvium. river systems paleo-Indigirka and paleo-Kolyma, whose traces on seabed can still be discerned. Most of the archipelagos and individual islands found in the shelf area are composed of rocks of this basement (Medvezhiy, Rautan, Shalaurova Islands, part of Ayon Island, etc.). In the region of the De Long Islands and in the northern part of the sea, there is the so-called Hyperborean platform (according to Shatsky). Aeromagnetic surveys confirm the presence in this area of a solid crystalline basement, overlapped and bordered by Mesozoic rocks, in places crumpled into folds.

The bottom sediments of the shelf consist mainly of sandy silt containing crushed boulders and pebbles; some of them are fragments of rocks about. Wrangel or other islands brought by ice.

2.3. Characteristic climate.

Located in high latitudes, the East Siberian Sea is located in the zone of atmospheric influences of the Atlantic and Pacific Oceans. The western part of the sea (although rarely) is penetrated by cyclones of Atlantic origin, eastern regions- Pacific. The climate of the East Siberian Sea is polar maritime, but with signs of continentality.

In winter, the main influence on the sea is exerted by the spur of the Siberian High, which goes to the coast, and the crest of the polar anticyclone is weakly expressed. In this regard, south-westerly and southerly winds prevail over the sea at a speed of 6-7 m/s. They bring cold air from the continent, so the average monthly air temperature in January is about -28-30°. In winter, there is calm, clear weather, which on some days is disturbed by cyclonic intrusions. Atlantic cyclones in the west of the sea cause increased winds and some warming, while Pacific cyclones, which have cold continental air in the rear, only increase wind speed, cloudiness and cause snowstorms in the southeastern part of the sea. In mountainous areas of the coast, the passage of Pacific cyclones is associated with the formation of a local wind - foehn. It usually reaches storm strength, causing some increase in temperature and a decrease in air humidity.

In summer, the pressure over the mainland of Asia is lowered, and over the sea it is increased, so the northerly winds prevail. At the beginning of the season they are very weak, but during the summer their speed gradually increases, reaching an average of 6-7 m/s. By the end of summer, the western part of the East Siberian Sea becomes one of the most turbulent sections of the Northern Sea Route. Often the wind blows at a speed of 10-15 m/s. The strengthening of the wind here is associated with hair dryers. The southeastern part of the sea is much calmer. Steady north and northeast winds cause low temperature air. The average July temperature is 0-1 ° in the north of the sea and 2-3 e in coastal areas. In the summer, the weather over the East Siberian Sea is predominantly cloudy with light drizzle, sometimes it snows.

There are almost no heat returns in autumn, which is explained by the remoteness of the sea from the oceanic centers of atmospheric action and their weak influence on atmospheric processes. Relatively cold summers throughout the sea, stormy weather at the end of summer and especially in autumn in the marginal regions of the sea, and calm in its central part are the characteristic climatic features of the sea. The speed of northwestern and northeastern winds often reaches 20-25 m/s. They cause waves up to 4-5 m high. Western winds contribute to the formation of a warm current going eastward from the Kolyma region. Exactly this warm current clears the Long Strait of ice. Away from the coast, storm wind speeds often reach 40-45 m/s.

Most of the year the sea is covered with ice. In its eastern part, floating ice often remains close to the coast even in summer. Observations carried out at high-latitude stations showed that the direction of ice drift depends on the distribution of atmospheric pressure. In winter, when a high pressure area develops near the pole, the anticyclonic (clockwise) circulation of water increases, which forces the ice to drift in a northwesterly direction. The average daily ice drift speed is 3-8 km.

When the polar anticyclone weakens, the area of cyclonic water circulation expands, which prevents the removal of ice from the area and, conversely, favors the inflow of multi-year ice from high latitudes and the accumulation of ice in the Long Strait.

2.4. hydrological regime.

The annual precipitation is 100-200 mm, and the river runoff, in contrast to the Kara Sea and the Laptev Sea, is not very large. Several significant rivers flow into the East Siberian Sea, the largest of which is the river. Kolyma. Its annual runoff is 132 km3. The second largest runoff river. Indigirka brings 59 km 3 of water. The total continental runoff into the East Siberian Sea is about 250 km 3 /year, which is only 10% of the total river runoff into all Arctic seas. All river water enters the southern part of the sea, and approximately 90% of the runoff falls, as in other Arctic seas, during the summer months.

Given the very vast size of the East Siberian Sea, coastal runoff does not significantly affect its general hydrological regime, but only determines some hydrological features of coastal areas in summer. High latitudes, free communication with the Central Arctic Basin, high ice coverage and low river flow determine the main features of the hydrological conditions of the East Siberian Sea.

The current system of the East Siberian Sea has been poorly studied. The general circulation of the sea waters is cyclonic in nature. From the Sannikov and Dmitry Laptev straits, water moves along the coast to the east. Near about. Wrangel part of the current turns to the north, continuing to move counterclockwise, and the other part passes to the east through the strait. Long (between Wrangel Island and the continental coast). The northward current is drawn into the Transarctic Current, turning to the northwest. Along the eastern shores of the Novosibirsk Islands, apparently, there is a current directed to the south and closing the cyclonic circulation.

Due to the shallow water and the absence of deep trenches extending beyond the northern limits of the East Siberian Sea, the vast majority of its spaces from the surface to the bottom are occupied by surface Arctic waters. Only in relatively limited estuarine areas is a kind of water formed as a result of mixing river and sea waters. It is characterized by high temperature and low salinity.

Constant currents on the surface of the East Siberian Sea form a weakly expressed cyclonic circulation. Along the mainland coast, there is a steady transfer of water from west to east. At Cape Billing, part of the waters is directed to the north and northwest and carried to the northern margins of the sea, where it is included in the streams going to the west. In different synoptic situations, the movement of waters also changes. Part of the water from the East Siberian Sea is carried out through the Long Strait into the Chukchi Sea. Permanent currents are often disturbed by wind currents, which are often stronger than permanent currents. The influence of tidal currents is relatively small.

Tides. Regular semidiurnal tides are observed in the East Siberian Sea. They are caused by a tidal wave that enters the sea from the north and moves towards the coast of the mainland. Its front is stretched from the north-north-west to the east-south-east from the New Siberian Islands to about. Wrangel.

The tides are most pronounced in the north and northwest. As they move south, they weaken, as the ocean tidal wave is largely damped in the vast shallow water. Thus, in the section from Indigirka to Cape Shelagsky, tidal level fluctuations are almost not noticeable. To the west and east of this area, the tide is also small - 5-7 cm. At the mouth of the Indigirka, the configuration of the banks and the bottom topography contribute to an increase in tides to 20-25 cm. Level changes caused by meteorological reasons are much more developed on the coast of the mainland.

The annual course of the level is characterized by its highest position in June - July, when there is an abundant inflow of river waters. The decrease in continental runoff in August leads to a decrease in the level by 50-70 cm. As a result of the predominance of surge winds in autumn, in October, the level rises.

In winter, the level drops and in March - April reaches its lowest position.

IN summer season surge phenomena are very pronounced, in which level fluctuations are often 60-70 cm. At the mouth of the Kolyma and in the Dmitry Laptev Strait, they reach maximum values for the entire sea - 2.5 m. abrupt change level positions - one of characteristic features coastal areas of the sea.

Significant waves develop in the ice-free areas of the sea. It is strongest during stormy northwestern and southeastern winds, which have the largest accelerations over the surface. clean water. Maximum Heights waves reach 5 m, usually their height is 3-4 m. Strong excitement is observed mainly in late summer - early autumn (September), when the ice edge recedes to the north. The western part of the sea is more stormy than the eastern one. Its central regions are relatively calm.

Water temperature on the surface in all seasons generally decreases from south to north. In winter, it is close to the freezing point and is equal to -0.2-0.6° near the mouths of the rivers, and 1.7-1.8° near the northern borders of the sea. In summer, the distribution of surface temperature is determined by the ice conditions. The water temperature in bays and bays reaches 7-8°, in open, ice-free areas 2-3°, and near the ice edge it is close to 0°.

The change in water temperature with depth in winter and spring is hardly noticeable. Only near the mouths of large rivers does it decrease to -0.5° in the subglacial horizons and to -1.5° near the bottom. In summer, in free ottold spaces, the water temperature drops slightly from the surface to the bottom in the coastal zone in the west of the sea. In its eastern part, surface temperature is observed in the 3-5 m layer, from where it drops sharply to 5-7 m horizons and then gradually decreases to the bottom. In the zones of influence of coastal runoff, a uniform temperature covers a layer up to 7-10 m, between horizons of 10-20 m it sharply, and then gradually decreases to the bottom. The shallow, slightly warm East Siberian Sea is one of the coldest Arctic seas.

Salinity on the surface generally increases from southwest to northeast. In winter and spring it is 4 -5°/ 00 near the mouths of the Kolyma and Indigirka, reaches values of 24-26°/ 00 near the Bear Islands, increases to 28-30°/ 00 in the central regions of the sea and rises to 31-32°/ 00 on its northern margins. In summer, as a result of the inflow of river waters and the melting of ice, the surface salinity decreases to 18-22°/00 in the coastal zone, 20-22°/00 near the Bear Islands, to 24 - 26 ° / 00 in the north, at the edge of melting ice.

In winter, in most of the sea, salinity slightly increases from the surface to the bottom. Only in the northwestern region, where ocean waters penetrate from the north, salinity increases from 23°/00 in the upper layer 10-15 m thick to 30°/00 near the bottom. Near the mouth areas, the upper desalinated layer up to horizons of 10-15 m is underlain by more saline waters. From the end of spring and during summer, a desalinated layer 20–25 m thick forms on ice-free spaces, under which salinity increases with depth. Consequently, in shallow areas (down to depths of 10-20 and even up to 25 m), freshening covers the entire water column. In deeper areas in the north and east of the sea, at horizons of 5-10 m, and in some places 10-15 m, salinity increases sharply, and then gradually and slightly rises to the bottom.

In the autumn-winter season, the density of water is higher than in spring and summer. The density is greater in the north and east than in the west of the sea, where desalinated waters from the Laptev Sea penetrate. However, these differences are small. Generally density increases with depth. Its vertical distribution is similar to the course of salinity.

The different degree of water overstratification creates different conditions for the development of mixing in different areas of the East Siberian Sea. In relatively weakly stratified and ice-free spaces, strong winds in summer mix water up to 20-25 m horizons. Consequently, in areas limited by a depth of 25 m, wind mixing extends to the bottom. In places of sharp stratification of waters in density, wind mixing penetrates only to horizons of 10-15 m, where it is limited by significant vertical density gradients.

Autumn-winter convection in the East Siberian Sea at depths of 40-50 m, which occupy more than 70% of its entire area, penetrates to the bottom. By the end of the cold season, the winter vertical circulation extends to horizons of 70-80 m, where it is limited by the great vertical stability of the waters.

2.5. Ice regime

The East Siberian Sea is the most arctic of the seas of the Soviet Arctic. From October - November to June - July it is completely covered with ice. At this time, the flow of ice from the Arctic Basin to the sea prevails, in contrast to other seas of the Arctic, where outward ice drift prevails. A characteristic feature of the ice of the East Siberian Sea is the significant development of fast ice in winter. At the same time, it is most widely distributed in the western, shallow part of the sea and occupies a narrow coastal strip in the east of the sea. In the west of the sea, the width of fast ice reaches 400-500 km. Here it joins the fast ice of the Laptev Sea. In the central regions its width is 250-300 km and to the east of Cape Shelagsky - 30-40 km. The fast ice boundary approximately coincides with the 25 km isobath, which runs 50 km north of the New Siberian Islands, then turns southeast, approaching the coast of the mainland near Cape Shelagsky. By the end of winter, the thickness of fast ice reaches 2 m. From west to east, the thickness of fast ice decreases. Drifting ice is located behind the fast ice. Usually this is one-year and two-year ice 2-3 m thick. In the very north of the sea, multi-year Arctic ice is found. The prevailing southerly winds in winter often carry drifting ice away from the northern edge of the fast ice. As a result, significant expanses of clear water and young ice appear, forming in the west the Novosibirsk and in the east the Zavrangelev stationary ice polynyas.

At the beginning of summer, after the breakup and destruction of fast ice, the position of the ice edge is determined by the action of winds and currents. However, ice is always found north of the band about. Wrangel - New Siberian Islands. In the western part of the sea, on the site of extensive fast ice, the Novosibirsk ice massif is being formed. It consists mainly of first-year ice and usually breaks up by the end of summer. The vast majority of space in the east of the sea is occupied by the spur of the Ayon oceanic ice massif, which largely forms heavy perennial ice. Its southern periphery during the whole year almost adjoins the coast of the mainland, determining the ice situation in the sea.

2.6. Biology.

The flora and fauna of the East Siberian Sea are qualitatively poor compared to neighboring seas, mainly due to severe ice conditions. However, in the areas of the mouths of the rivers, in addition to the omul, whitefish and grayling, there are large schools of white fish. (coregonidae). Other fish species have also been found there, which include polar smelt, navaga, polar cod, polar flounder and salmon fish: arctic char and nelma. Mammals are represented by walruses, seals and polar bears, birds - guillemots, sea gulls, cormorants. Cold-loving brackish-water forms are found in the central regions. Fishing is of local importance.

BIBLIOGRAPHY:

1. Bogdanov D.V. Oceans and seas on the eve of the XXI century. – M.: Nauka, 1991. – 128 p.

2. Sukhovey F.S. Seas of the oceans. - L.: Gidrometeoizdat, 1986. - 288 p.

3. Oceanographic Encyclopedia.- L.: Gidrometeoizdat, 1974. - 632 p.

4. Zalogin B. S., Kosarev A. N. Seas. - M.: Thought, 1999. - 400 p.

5. Nikiforov E. G., Shpayher A. O. Patterns of formation of large-scale fluctuations in the hydrological regime of the Arctic Ocean. - L .: Gidrometeoizdat, 1980. - 270 p.

East-Siberian Sea- marginal sea of the Arctic Ocean, located between the New Siberian Islands and Wrangel Island. Surface area 913,600 km². Already from the name it is clear that this sea is located off the northern coast of Eastern Siberia. The borders of the East Siberian Sea are mainly conditional lines, and only in some parts it is limited by land. The waters of this sea communicate well with the waters of the Arctic Ocean, therefore the East Siberian Sea belongs to the type of continental marginal seas. There are very few islands in the waters of the East Siberian Sea. The coastline of the sea has large bends.

seafaring

In the first half of the 17th century, the Cossacks who mastered Kolyma and Indigirka went downstream, went out to sea and went to Taimyr, where they reached the Yenisei, on the banks of which they hunted, by drag. The first exploratory voyage in the historical era was made by the Yakut Cossack Mikhailo Stadukhin in 1644. In June 1648, Stadukhin’s assistant Semyon Dezhnev traveled the entire eastern part of the sea from the mouth of the Kolyma and further through the Long Strait and the Bering Strait to the Gulf of Anadyr, where he founded the city of Anadyr. Thus, in 1648 the possibility of through navigation along the entire coast of the East Siberian Sea was shown.

The mainland shores of the sea and islands were described in the first half of the 18th century by the Great Northern Expedition. All these discoveries were made not on ships, but on sleds. In 1823, from the Chukchi, Wrangel heard a story about a large island in the north (not yet discovered Wrangel Island), where storms sometimes carried fishing boats. Wrangel Island was discovered in 1849 by the British frigate Herald, approaching it from the Chukchi Sea. West Coast The islands were discovered in 1867 by the American whaler Thomas Long on the schooner "Nile", whose ship passed between the mainland and the island through the strait, which is now called Long's Strait. In September 1875, the East Siberian Sea was crossed on the sail-steam vessel "Vega" by Baron Adolf Erik Nordenskiöld, the first navigator who managed to pass the Northern Sea Route along the entire coast of Asia. Next, the De Long Islands were discovered. In 1913, the icebreaking ships Taimyr and Vaigach discovered the island, which was named after Vilkitsky, an assistant to the head of the expedition. The last discovery was made by the next expedition of "Taimyr" and "Vaigach" on August 27, 1914, when Lieutenant Zhokhov, the watchman of the "Vaigach", noticed an island with coordinates 76 ° 10 "N 153 ° E, which received the name Zhokhov Island. After 1932 , when the icebreaker "Sibiryakov" passed the Northern Sea Route in one navigation, regular voyages of ships are made to the East Siberian Sea.

Bottom relief

The sea lies on the shelf. The underwater relief of the space occupied by the East Siberian Sea is a plain. This plain has a slight slope from the southwest to the northeast. The bottom of the sea is predominantly flat, without significant depressions and elevations. Most of the water expanses of the East Siberian Sea have a depth of up to 20 - 25 m. The deepest gutters are located on the sea bottom in the northeastern part of the mouths of the Indigirka and Kolyma rivers. There is an assumption that these trenches used to be areas of river valleys. But later these rivers were flooded with the sea. In the northeast of the sea there are quite deep places. Max Depth- 915 meters.

Climate and hydrological regime

The climate of the East Siberian Sea has a distinctive feature: the sea is influenced by the Atlantic and Pacific oceans. average temperature in January it is approximately - 28 - 30 0 C. In winter, the weather is mostly clear. Only sometimes cyclones break the settled calm weather for several days. Atlantic cyclones, which prevail in the western part of the sea, contribute to increased wind and temperature rise. Pacific cyclones, which dominate the southeastern part of the sea, bring strong winds, snowstorms and cloudy weather. The average July temperature is about 0 + 4 0 C. The decrease in the temperature of the northern part of the sea is affected by the influence of Arctic ice. In the southern part of the sea, proximity to a warm mainland contributes to an increase in temperature. The East Siberian Sea in summer is characterized by overcast weather. Very often there are light rains, and occasionally even sleet.

Sea water temperatures are low, in the north they are close to −1.8°C both in winter and summer. To the south in summer the temperature rises in the upper layers to 5°C. The salinity of the sea is different in the western and eastern parts of the sea. River runoff leads to a decrease in salinity to 10-15‰, and in the mouths of large rivers to almost zero. With depth, salinity rises to 32‰. Almost the whole year the sea is covered with ice. In the eastern part of the sea, floating perennial ice remains even in summer.

Flora and fauna

The flora and fauna of the East Siberian Sea is poor due to severe ice conditions. But in the areas adjacent to the mouths of the rivers, there are omul, whitefish, grayling, polar smelt, navaga, polar cod and flounder, salmon - char and nelma. From mammals there are walrus, seals, polar bear; birds - guillemots, gulls, cormorants.

Economic importance

The coastal zone is characterized as an area with weak economic activity. Fishing is of local importance. The Northern Sea Route passes through the East Siberian Sea; the main port of Pevek (Chaun Bay). The East Siberian Sea is a promising oil and gas region, the development of which is difficult due to harsh natural conditions.

Ecology

The waters of the East Siberian Sea are relatively clean. Only in the bay of Pevek, slight water pollution was noted, but in Lately the environment is improving. The waters of the Chaun Bay are slightly polluted with petroleum hydrocarbons.

located between the New Siberian Islands and Wrangel Island. The southern border runs along the mainland coast from Cape Yakan to Cape Svyatoy Nos.
The East Siberian Sea belongs to the type of continental marginal seas. Its area is 913 thousand km2, volume - 49 thousand km3, average depth - 54 m, maximum depth - 915 m, i.e. this sea lies entirely on the continental shelf.

The landscapes of the western part of the coast of the East Siberian Sea differ sharply from the eastern part. In the section from the New Siberian Islands to the mouth of the Kolyma River, the banks are very low and monotonous. Here the swampy tundra approaches the sea. To the east of the mouth of the Kolyma River, behind Cape Bolshoy Baranov, the coast becomes mountainous. From the mouth of the Kolyma River to the island of Aion, low hills approach the water directly, in places abruptly breaking off. The Chaun Bay is framed by low, but steeply flat banks. Different in relief and structure, the coast of the sea in different areas refers to different morphological types of coasts.

The underwater relief of the shelf that forms the bed of the sea, in general terms, is a plain, very slightly inclined from the southwest to the northeast. The bottom of the sea has no noticeable depressions and hills. It is believed that these are traces of ancient river valleys flooded by the sea. The area of shallow depths in the western part of the sea forms the Novosibirsk shoal. The greatest depths are concentrated in the northeastern part of the sea. A noticeable increase in depth occurs in the horizon from 100 to 200 m.

Located in high latitudes, the East Siberian Sea is located in the zone of atmospheric influences of the Atlantic and Pacific oceans. Cyclones of Atlantic origin (although rarely) penetrate into the western part of the sea, and Pacific cyclones penetrate into the eastern regions. The climate of the East Siberian Sea is polar maritime, but with signs of continentality.

The continental runoff in the East Siberian Sea is relatively small, about 250 m3/km, which is only 10% of the total river runoff in all Arctic seas. The largest of the flowing rivers - Kolyma - produces about 130 km3 of water per year, and the second largest river - Indigirka - 60 km3 of water per year. All other rivers pour approximately 350 km3 of water into the sea during the same time.

Due to the shallow water and the absence of deep trenches extending beyond the northern limits of the East Siberian Sea, the vast majority of its spaces from the surface to the bottom are occupied by surface Arctic waters.
Constant currents on the surface of the East Siberian Sea form a weakly expressed cyclonic circulation.
Regular semidiurnal tides are observed in the East Siberian Sea. They are caused by a tidal wave that enters the sea from the north and moves towards the coast of the mainland. Its front is stretched from the north-north-west to the east-south-east from the New Siberian Islands to Wrangel Island.

The annual course of the level is characterized by its highest position in June - July, when there is an abundant inflow of river waters.

In the summer season, surge phenomena are very pronounced, in which level fluctuations are often - 60 cm. At the mouth of the Kolyma River and in the Dmitry Laptev Strait, they reach the maximum size for the entire sea - 2.5 m. A fast and abrupt change in level positions is one of the characteristic features of the coastal regions of the sea.

The East Siberian Sea is the most arctic of the seas of the Russian Arctic. From October - November to June - July it is completely covered with ice. At this time, the flow of ice from the Arctic Basin to the sea prevails, in contrast to other seas of the Arctic, where outward ice drift prevails. A characteristic feature of the ice of the East Siberian Sea is the significant development of fast ice in winter. At the same time, it is most widely distributed in the western, shallow part of the sea and occupies a narrow coastal strip in the east of the sea.

The vast majority of space in the east of the sea is occupied by the spur of the Ayon oceanic ice massif, which largely forms heavy perennial ice. Its southern periphery during the whole year almost adjoins the coast of the mainland, determining the ice situation in the sea.