Which ocean basin does the Sea of Okhotsk belong to? The Sea of Okhotsk became an inland sea of Russia
The Sea of Okhotsk juts out rather deeply into the land and is noticeably elongated from the southwest to the northeast. It has coastlines almost everywhere. From Sea of Japan it is separated by Sakhalin and conditional lines of Cape Suschev - Cape Tyk (Nevelskoy Strait), and in the La Perouse Strait - Cape Soya - Cape Crillon. The southeastern boundary of the sea runs from Cape Nosappu (Hokkaido Island) and through the Kuril Islands to Cape Lopatka (Kamchatka Peninsula).
The Sea of Okhotsk is one of the largest and deep seas peace. Its area is 1,603 thousand km 2, volume - 1,316 thousand km 3, average depth - 821 m, maximum depth - 3,521 m.
The Sea of Okhotsk belongs to the marginal seas of the mixed continental-oceanic type. It is separated from the Pacific Ocean by the Kuril ridge, which has about 30 large, many small islands and rocks. The Kuril Islands are located in the seismic activity belt, which includes more than 30 active and 70 extinct volcanoes. Seismic activity is manifested on the islands and under water. In the latter case, tsunami waves often form. In the sea there is a group of Shantarsky islands, the Spafaryev, Zavyalov, Yamsky islands and the small island of Iona - the only one of all remote from the coast. With a large length, the coastline is indented relatively weakly. However, it creates several large bays(Aniva, Patience, Sakhalin, Academies, Tugursky, Ayan, Shelikhov) and lips (Udskaya, Tauiskaya, Gizhiginskaya and Penzhinskaya).
The Nevelskoy and La Perouse straits are comparatively narrow and shallow. The width of the Nevelskoy Strait (between Capes Lazarev and Pogibi) is only about 7 km. The width of the La Perouse Strait is 43-186 km, the depth is 53-118 m.
The total width of the Kuril Straits is about 500 km, and maximum depth the deepest of them, the Bussol Strait, exceeds 2300 m. Thus, the possibility of water exchange between the Sea of Japan and the Sea of Okhotsk is incomparably less than between the Sea of Okhotsk and the Pacific Ocean.
However, even the depth of the deepest of the Kuril Straits is much less than the maximum depth of the sea, and therefore Kuril ridge is a huge threshold that separates the depression of the sea from the ocean.
The most important for water exchange with the ocean are the straits of Bussol and Krusenstern, as they have the largest area and depth. The depth of the Bussol Strait was indicated above, and the depth of the Kruzenshtern Strait is 1920 m. The Frieze, Fourth Kuril, Rikord and Nadezhda straits are of less importance, the depths of which are more than 500 m. The depths of the remaining straits generally do not exceed 200 m, and their areas are insignificant.
On distant shores
coast Sea of Okhotsk in different regions belong to different geomorphological types. For the most part, these are abrasion shores altered by the sea, and only in Kamchatka and Sakhalin are accumulative shores found. In general, the sea is surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. The coasts along the Sakhalin Bay are low. The southeastern coast of Sakhalin is low, and the northeastern coast is low. coast Kuril Islands very abrupt. The northeastern coast of Hokkaido is predominantly low-lying. The coast of the southern part of Western Kamchatka has the same character, but the coast of its northern part rises somewhat.
Shores of the Sea of Okhotsk
Bottom relief
The bottom relief of the Sea of Okhotsk is varied. Northern part The sea is a continental shelf - an underwater continuation of the Asian mainland. The width of the continental shoal in the area of the Ayano-Okhotsk coast is approximately 185 km, in the area of the Uda Bay - 260 km. Between the meridians of Okhotsk and Magadan, the width of the shoal increases to 370 km. WITH western edge the basin of the sea is the island sandbar of Sakhalin, from the east - the sandbar of Kamchatka. The shelf occupies about 22% of the bottom area. The rest most of(about 70%) of the sea is located within the continental slope (from 200 to 1500 m), on which separate underwater heights, depressions and trenches stand out.
The deepest South part sea (more than 2500 m), which is a part of the bed, occupies 8% of the total sea area. It is stretched as a strip along the Kuril Islands and gradually narrows from 200 km against about. Iturup up to 80 km against the Krusenstern Strait. Great depths and significant slopes of the bottom distinguish the southwestern part of the sea from the northeastern part, which lies on the continental shelf.
Of the major elements of the relief of the bottom of the central part of the sea, two underwater hills stand out - the Academy of Sciences and the Institute of Oceanology. Together with the protrusion of the continental slope, they divide the sea basin into three basins: the northeastern one - the TINRO basin, the northwestern one - the Deryugin basin, and the southern deep-water basin - the Kuril basin. The depressions are connected by gutters: Makarov, P. Schmidt and Lebed. To the northeast of the TINRO depression, the Shelikhov Bay trough extends.
The least deep is the TINRO basin, located to the west of Kamchatka. Its bottom is a plain lying at a depth of about 850 m, with a maximum depth of 990 m.
The Deryugin depression is located to the east of the Sakhalin submerged base. Its bottom is a flat, elevated plain at the edges, lying on average at a depth of 1700 m, the maximum depth of the depression is 1744 m.
The deepest Kuril depression. This is a huge flat plain lying at a depth of about 3300 m. Its width in the western part is about 212 km, and its length in the northeast direction is about 870 km.
Bottom relief and currents of the Sea of Okhotsk
currents
Under the influence of winds and water inflow through the Kuril Straits, character traits systems of non-periodic currents of the Sea of Okhotsk. The main one is the cyclonic system of currents, covering almost the entire sea. It is due to the predominance of cyclonic circulation of the atmosphere over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic gyres are traced in the sea: to the west of the southern tip of Kamchatka (approximately between 50-52°N and 155-156°E); above the TINRO depression (55-57°N and 150-154°E); in the area of the Southern Basin (45-47°N and 144-148°E). In addition, a vast area of cyclonic circulation of waters is observed in the central part of the sea (47-53 ° N and 144-154 ° E), and a cyclonic circulation is observed to the east and north-east of the northern tip of the island. Sakhalin (54-56°N and 143-149°E).
Strong currents bypass the sea along the coastline counterclockwise: the warm Kamchatka Current, directed northward into Shelikhov Bay; flow of western and then south-western direction along the northern and northwestern coasts of the sea; the steady East Sakhalin Current going south, and the rather strong Soya Current entering the Sea of Okhotsk through the Laperouse Strait.
On the southeastern periphery of the cyclonic gyre in the central part of the sea, a branch of the Northeast Current is distinguished, which is opposite in direction to the Kuril Current in the Pacific Ocean. As a result of the existence of these streams, stable areas of convergence of currents are formed in some of the Kuril Straits, which leads to subsidence of waters and has a significant effect on the distribution of oceanological characteristics not only in the straits, but also in the sea itself. And finally, one more feature of the water circulation in the Sea of Okhotsk is two-way stable currents in most of the Kuril straits.
Surface currents on the surface of the Sea of Okhotsk are most intense near the western coast of Kamchatka (11–20 cm/s), in the Sakhalin Bay (30–45 cm/s), in the area of the Kuril Straits (15–40 cm/s), over the South Basin ( 11-20 cm/s) and during the Soya (up to 50-90 cm/s). In the central part of the cyclonic region, the intensity of horizontal transport is much less than on its periphery. In the central part of the sea, velocities vary from 2 to 10 cm/s, with velocities below 5 cm/s predominating. A similar picture is observed in Shelikhov Bay: rather strong currents near the coast (up to 20–30 cm/s) and low velocities in the central part of the cyclonic gyre.
In the Sea of Okhotsk are well expressed different kinds periodic tidal currents: semidiurnal, diurnal and mixed with a predominance of semidiurnal or diurnal components. The velocities of tidal currents range from a few centimeters to 4 m/s. Away from the coast, the current velocities are small - 5-10 cm/s. In straits, bays and off the coast, their speeds increase significantly. For example, in the Kuril Straits, current velocities reach 2-4 m/s.
The tides of the Sea of Okhotsk have a very complex character. A tidal wave enters from the south and southeast from the Pacific Ocean. The semidiurnal wave moves to the north, and at the 50° parallel it is divided into two parts: the western one turns to the northwest, the eastern one moves towards Shelikhov Bay. The diurnal wave also moves to the north, but at the latitude of the northern tip of Sakhalin it is divided into two parts: one enters Shelikhov Bay, the other reaches the northwestern coast.
Diurnal tides are the most widespread in the Sea of Okhotsk. They are developed in the Amur Estuary, Sakhalin Bay, on the coast of the Kuril Islands, off the western coast of Kamchatka and in Penzhinsky Bay. Mixed tides are observed on the northern and northwestern coasts of the sea and in the area of the Shantar Islands.
The highest tides (up to 13 m) were recorded in the Penzhina Bay (cape Astronomichesky). In the area of the Shantar Islands, the tide exceeds 7 m. The tides are significant in the Sakhalin Bay and in the Kuril Straits. In the northern part of the sea, their size reaches 5 m.
Fur seal rookery
The lowest tides were observed off the eastern coast of Sakhalin, in the area of the La Perouse Strait. In the southern part of the sea, the tides are 0.8-2.5 m.
In general, tidal level fluctuations in the Sea of Okhotsk are very significant and have a significant impact on its hydrological regime, especially in coastal zone.
In addition to tidal fluctuations, surge fluctuations in the level are also well developed here. They occur mainly during the passage of deep cyclones over the sea. Surge rises in the level reach 1.5-2 m. The largest surges are noted on the coast of Kamchatka and in the Gulf of Patience.
Significant size and great depths Sea of Okhotsk, frequent and strong winds over it cause the development of large waves here. The sea is especially stormy in autumn, and in ice-free areas in winter. These seasons account for 55-70% of storm waves, including those with wave heights of 4-6 m, and the highest wave heights reach 10-11 m. The most restless are the southern and southeastern regions of the sea, where the average frequency of storm waves is 35 -40%, and in the northwestern part it decreases to 25-30%. With strong excitement in the straits between the Shantar Islands, a crowd is formed.
Climate
The Sea of Okhotsk is located in the monsoon climate zone of temperate latitudes. A significant part of the sea in the west deeply protrudes into the mainland and lies relatively close to the cold pole of the Asian land, so the main source of cold for the Sea of Okhotsk is located to the west of it. The relatively high ridges of Kamchatka make it difficult for warm Pacific air to penetrate. Only in the southeast and south is the sea open to the Pacific Ocean and the Sea of Japan, from where a significant amount of heat enters it. However, the influence of cooling factors is stronger than warming factors, so the Sea of Okhotsk is generally cold. At the same time, due to the large meridional extent, there are significant differences in the synoptic situation and meteorological conditions. In the cold part of the year (from October to April), the Siberian anticyclone and the Aleutian low act on the sea. The influence of the latter extends mainly to the southeastern part of the sea. This distribution of large-scale baric systems causes strong persistent northwestern and northern winds often reaching storm strength. Low winds and calms are almost completely absent, especially in January and February. In winter, the wind speed is usually 10-11 m/s.
The dry and cold Asian winter monsoon significantly cools the air over the northern and northwestern regions of the sea. In the coldest month - January - the average air temperature in the north-west of the sea is -20 - 25 °, in central regions–10-15°, and in the south-eastern part of the sea it is equal to –5-6°.
In autumn and winter, cyclones of predominantly continental origin come out to sea. They bring with them an increase in wind, sometimes a decrease in air temperature, but the weather remains clear and dry, as continental air comes from the cooled mainland. In March-April, large-scale baric fields are restructured. The Siberian anticyclone is collapsing, and the Hawaiian high is intensifying. As a result, during the warm season (from May to October), the Sea of Okhotsk is under the influence of the Hawaiian maximum and the area of low pressure located over Eastern Siberia. At this time, weak southeasterly winds prevail over the sea. Their speed usually does not exceed 6-7 m/s. Most often, these winds are observed in June and July, although stronger northwesterly and northerly winds are sometimes observed in these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since the horizontal pressure gradients are smoothed out in the warm season.
In summer, the average monthly air temperature in August decreases from the southwest (from 18°) to the northeast (up to 10-10.5°).
During the warm season over southern part seas quite often pass tropical cyclones - typhoons. They are associated with an increase in wind to a storm, which can last up to 5-8 days. The predominance of southeasterly winds in the spring-summer season leads to significant cloudiness, precipitation, and fog.
Monsoon winds and stronger winter cooling of the western part of the Sea of Okhotsk compared to the eastern part are important climatic features this sea.
Quite a few mostly small rivers flow into the Sea of Okhotsk, therefore, with a significant volume of its waters, the continental runoff is relatively small. It is equal to about 600 km 3 /year, while about 65% of the flow comes from the Amur. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring much less fresh water to the sea. The flow comes mainly in spring and early summer. At this time, its greatest influence is felt mainly in the coastal zone, near the mouth areas of large rivers.
Hydrology and water circulation
Geographical position, large length along the meridian, monsoonal change of winds and good connection of the sea with the Pacific Ocean through the Kuril Straits are the main natural factors, which most significantly affect the formation of the hydrological conditions of the Sea of Okhotsk. The values of heat input and output in the sea are determined mainly by the rational heating and cooling of the sea. The heat brought by the Pacific waters is of subordinate importance. However, for the water balance of the sea, the inflow and outflow of water through the Kuril Straits plays a decisive role.
The flow of surface Pacific waters into the Sea of Okhotsk occurs mainly through the northern straits, in particular through the First Kuril. In the straits of the middle part of the ridge, both the inflow of Pacific waters and the outflow of Okhotsk waters are observed. So, in the surface layers of the Third and Fourth straits, apparently, there is a runoff of water from the Sea of Okhotsk, in the near-bottom ones - an inflow, and in the Bussol Strait - on the contrary: in the surface layers - an inflow, in the deep - a drain. In the southern part of the ridge, mainly through the straits of Ekaterina and Friza, there is mainly a runoff of water from the Sea of Okhotsk. The intensity of water exchange through the straits can vary significantly.
In the upper layers of the southern part of the Kuril ridge, the runoff of the Sea of Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, Pacific waters enter. In the deep layers, the inflow of Pacific waters prevails.
Water temperature and salinity
The inflow of Pacific waters significantly affects the distribution of temperature, salinity, formation of the structure and general circulation of the waters of the Sea of Okhotsk. It is characterized by a subarctic structure of waters, in which cold and warm intermediate layers are well expressed in summer. A more detailed study of the subarctic structure in this sea has shown that the Sea of Okhotsk, Pacific, and Kuril varieties of the subarctic water structure exist in it. With the same nature of the vertical structure, they have quantitative differences in the characteristics of water masses.
The following water masses are distinguished in the Sea of Okhotsk:
surface water mass with spring, summer and autumn modifications. It is a thin heated layer 15-30 m thick, which limits the upper maximum of stability, mainly due to temperature. This water mass is characterized by temperature and salinity corresponding to each season;
The Sea of Okhotsk water mass is formed in winter from surface water and in spring, summer and autumn it manifests itself in the form of a cold intermediate layer lying between horizons of 40-150 m. This water mass is characterized by a fairly uniform salinity (31-32.9‰) and different temperatures. In most of the sea, its temperature is below 0 ° and reaches -1.7 °, and in the region of the Kuril Straits it is above 1 °;
the intermediate water mass is formed mainly due to the sinking of waters along the underwater slopes, located within the sea from 100-150 to 400-700 m, and is characterized by a temperature of 1.5 ° and a salinity of 33.7‰. This water mass is distributed almost everywhere, except for the northern part of the sea, Shelikhov Bay and some areas along the coast of Sakhalin, where the Sea of Okhotsk water mass reaches the bottom. The thickness of the intermediate water mass layer decreases from south to north;
the deep Pacific water mass is the water of the lower part of the warm layer of the Pacific Ocean, which enters the Sea of Okhotsk at horizons below 800-1000 m, i.e. below the depth of the waters descending in the straits, and in the sea it appears as a warm intermediate layer. This water mass is located on the horizons of 600-1350 m, has a temperature of 2.3°C and a salinity of 34.3‰. However, its characteristics change in space. The highest values of temperature and salinity are observed in the northeastern and partly in the northwestern regions, which is associated here with the rise of waters, and the smallest values of the characteristics are characteristic of the western and southern regions, where the waters sink.
The water mass of the southern basin is of Pacific origin and represents the deep water of the northwestern part of the Pacific Ocean near the horizon of 2300 m, i.e. horizon corresponding to the maximum depth of the threshold in the Kuril Straits, located in the Bussol Strait. This water mass fills the basin from a horizon of 1350 m to the bottom and is characterized by a temperature of 1.85° and a salinity of 34.7‰, which vary only slightly with depth.
Among the identified water masses, the Sea of Okhotsk and the deep Pacific Ocean are the main ones; they differ from each other not only in thermohaline, but also in hydrochemical and biological indicators.
The water temperature on the sea surface decreases from south to north. In winter, almost everywhere, the surface layers cool down to a freezing temperature of -1.5-1.8°. Only in the southeastern part of the sea does it remain around 0°, and near the northern Kuril Straits, under the influence of Pacific waters, the water temperature reaches 1-2°.
Spring warming at the beginning of the season mainly goes to the melting of ice, only towards the end of it does the water temperature begin to rise.
In summer, the distribution of water temperature on the sea surface is quite diverse. In August, the waters adjacent to about. Hokkaido. In the central regions of the sea, the water temperature is 11-12°. The coldest surface waters are observed near about. Iona, near Cape Pyagin and near the Kruzenshtern Strait. In these areas, the water temperature is kept within 6-7 °. The formation of local centers of increased and decreased water temperature on the surface is mainly associated with the redistribution of heat by currents.
The vertical distribution of water temperature varies from season to season and from place to place. In the cold season, the change in temperature with depth is less complex and varied than in warm seasons.
In winter, in the northern and central regions of the sea, water cooling extends to horizons of 500–600 m. The water temperature is relatively uniform and varies from -1.5–1.7 ° on the surface to rises to 1-0°, in the southern part of the sea and near the Kuril Straits, the water temperature drops from 2.5-3° on the surface to 1-1.4° at the horizons of 300-400 m and then gradually rises to 1.9-2 ,4° in the bottom layer.
In summer, surface waters are warmed up to a temperature of 10-12°C. In the subsurface layers, the water temperature is slightly lower than on the surface. A sharp decrease in temperature to -1 - 1.2 ° is observed between horizons of 50-75 m, deeper, up to horizons of 150-200 m, the temperature quickly rises to 0.5 - 1 °, and then it rises more smoothly, and at horizons of 200 - 250 m is equal to 1.5 - 2 °. Further, the temperature of the water almost does not change to the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature drops from 10-14° on the surface to 3-8° at the 25-m horizon, then to 1.6-2.4° at the 100-m horizon and down to 1 ,4-2° at the bottom. The vertical temperature distribution in summer is characterized by a cold intermediate layer. In the northern and central regions of the sea, the temperature in it is negative, and only near the Kuril Straits does it have positive values. In different areas of the sea, the depth of the cold intermediate layer is different and varies from year to year.
The distribution of salinity in the Sea of Okhotsk varies relatively little from season to season. Salinity increases in the eastern part, which is under the influence of Pacific waters, and decreases in the western part, which is desalinated by continental runoff. In the western part, salinity on the surface is 28-31‰, and in the eastern part - 31-32‰ and more (up to 33‰ near the Kuril ridge),
In the northwestern part of the sea, due to desalination, the salinity on the surface is 25‰ or less, and the thickness of the desalinated layer is about 30-40 m.
Salinity increases with depth in the Sea of Okhotsk. At the horizons of 300-400 m in the western part of the sea, the salinity is 33.5‰, and in the eastern part it is about 33.8‰. At a horizon of 100 m, salinity is 34‰ and further towards the bottom it increases slightly, by only 0.5-0.6‰.
In some bays and straits, the salinity value, its stratification can differ significantly from the waters high seas depending on local conditions.
In accordance with temperature and salinity, denser waters are observed in winter in the northern and central regions of the sea covered with ice. The density is somewhat less in the relatively warm Kuril region. In summer, the water density decreases, its lowest values are confined to the zones of influence of coastal runoff, and the highest values are observed in the areas of distribution of Pacific waters. In winter, it rises slightly from the surface to the bottom. In summer, its distribution depends on temperature in the upper layers, and on salinity in the middle and lower horizons. IN summer time a noticeable density stratification of waters along the vertical is created, the density increases especially noticeably at the horizons of 25-50 m, which is associated with the heating of waters in open areas and desalination near the coast.
Wind mixing is carried out in the ice-free season. It flows most intensively in spring and autumn, when strong winds blow over the sea, and the stratification of waters is not yet very pronounced. At this time, wind mixing extends to horizons of 20-25 m from the surface.
Intense ice formation over most of the sea excites an enhanced thermohaline winter vertical circulation. At depths up to 250-300 m, it spreads to the bottom, and below it is prevented by the maximum stability that exists here. In areas with a rugged bottom topography, the spread of density mixing into the lower horizons is facilitated by the sliding of water along the slopes.
ice coverage
Severe and long winters with strong northwest winds contribute to the development of large masses of ice in the sea. The ice of the Sea of Okhotsk is exclusively of local formation. Here there are both fixed ice - fast ice, and floating ice, representing the main form of sea ice.
In different amounts, ice is found in all areas of the sea, but in summer the entire sea is cleared of ice. The exception is the region of the Shantar Islands, where ice can persist in summer.
Ice formation begins in November in the bays and bays of the northern part of the sea, in the coastal part of the island. Sakhalin and Kamchatka. Then ice appears in the open part of the sea. In January and February, ice covers the entire northern and middle parts of the sea.
In ordinary years, the southern boundary of a relatively stable ice cover bends to the north and runs from the La Perouse Strait to Cape Lopatka.
The extreme southern part of the sea never freezes. However, due to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.
From April to June there is a destruction and gradual disappearance of the ice cover. On average, the ice in the sea disappears in late May - early June. The northwestern part of the sea, due to the currents and the configuration of the coasts, is most of all clogged with ice, which persists until July. The ice cover in the Sea of Okhotsk lasts for 6-7 months. More than 3/4 of the sea surface is covered with floating ice. Close-knit ice in the northern part of the sea presents serious obstacles to navigation even for icebreakers.
The total duration of the ice period in the northern part of the sea reaches 280 days a year.
The southern coast of Kamchatka and the Kuril Islands are areas with low ice coverage: here, on average, ice stays for no more than three months a year. The thickness of the ice growing during the winter reaches 0.8-1 m.
strong storms, tidal currents they break open the ice cover in many areas of the sea, forming hummocks and large leads. In the open part of the sea, solid immovable ice is never observed, usually drifting ice here, in the form of vast fields with numerous leads.
Part of the ice from the Sea of Okhotsk is carried into the ocean, where it breaks up and melts almost immediately. IN harsh winters floating ice is pressed against the Kuril Islands by northwestern winds and clogs some of the straits.
Economic importance
There are about 300 species of fish in the Sea of Okhotsk. Of these, about 40 species are commercial. The main commercial fish are pollock, herring, cod, navaga, flounder, sea bass, capelin. Catches of salmon (chum salmon, pink salmon, sockeye salmon, coho salmon, chinook salmon) are small.
Sea of Okhotsk- one of the largest water basins washing the shores of our country.
Its area - 1,603,000 km 2 - is one and a half times larger than the area of the Sea of Japan and is second only to the Bering Sea, from which it is separated by the Kamchatka Peninsula. The chain of active and extinct volcanoes of the Kuril island ridge separates the Sea of Okhotsk from the Pacific Ocean, and the islands of Hokkaido and Sakhalin from the Sea of Japan. Penzhina Bay in the north, Udskaya in the west, Tugursky, Academies, Patience and Aniva bays in the south go deep into the land. Completely closed in the north, the Sea of Okhotsk in the west exchanges waters with the Pacific Ocean through 19 Kuril straits, and further south, through the La Perouse and Tatar Straits, with the Sea of Japan. Coastline it stretched for 10,444 km.
Morse covers the ancient land of Okhotia, and therefore it is shallow in most of its water area. Only in the South Okhotsk Basin does the depth reach 3372 m. If you look at the geomorphological map of the Sea of Okhotsk, you can find a number of depressions and uplifts on it: the USSR Academy of Sciences Upland, the TINRO and Deryugin depressions, the Makarov and Pyotr Schmidt trenches. In the north, the shelf of the Sea of Okhotsk is shallow, towards the south the depths gradually increase. The shelf area is 36% of the entire sea area.
The Sea of Okhotsk feeds many large and small rivers, but its main artery is the Amur, the great river of East Asia. The shores of the Sea of Okhotsk Islands and the Kamchatka Peninsula are mostly low-lying, marshy, with relict salt lakes, bays and lagoons. Especially a lot of them on Sakhalin. The western coast of the Sea of Okhotsk is mountainous, with steep, straight banks. The Pribrezhny and Ulinsky ridges and the spurs of the Suntar-Khayat ridge come close to the sea near Ayan, Okhotsk and Magadan.
In the Sea of Okhotsk, almost all islands are located near the coast. The largest of them is Sakhalin, whose area is 76,400 km 2. The Kuril archipelago, stretching for 1200 km between the Japanese island of Hokkaido and Cape Lopatka in Kamchatka, has 56 islands (except for small ones of volcanic origin). Volcanologists have identified and taken into account here. 38 active and 70 extinct volcanoes. The Shantar Islands are located in the extreme west of the sea. The most significant of them is Big Shantar. Its area is 1790 km2. Some of these 15 islands have long been inhabited by birds and attract the attention of scientists. To the south of the Patience Peninsula is the small island of Seals, famous for its seal rookery. But the tiny island of Iona, lying 170 miles east of Ayan, is just a lonely rock, visited only by sea birds and sea lions. In addition to these fragments of land, at the very top of the Sakhalin Bay, there are the islands of Chkalov, Baidukov and Belyakov, named after the brave Soviet aces.
The water masses of the Sea of Okhotsk, moving mainly counterclockwise, form a cyclonic system of currents. This is due to two main factors - the runoff of river waters and the inflow of warm waters of the Pacific Ocean through the Kruzenshtern and Bussol straits. Around the Shantar Islands there is a roundabout in reverse direction(clockwise), reminiscent of the currents in the bays of Anise and Patience.
Branches of two powerful water currents enter the south of the sea - the warm current Kuro-Sivo and the cold Oya-Sivo. In addition to these currents, jets of the warm current Soya penetrate into the Sea of Okhotsk through the La Perouse Strait. The influence of warm currents increases in summer and weakens in winter. In addition to the Oya-Sivo Current, which flows into the Sea of Okhotsk through the Kuril Straits, cooling of the waters also causes the alongshore East Sakhalin Current, directed from north to south. Through the southern Kuril straits, cold waters leave for the Pacific Ocean.
The Sea of Okhotsk is known for its powerful tides. In the Penzhina Bay, their height reaches almost 13 m (a kind of record for the USSR), a slightly smaller difference in sea levels at high (high tide) and low (low tide) water is observed in the Gizhiginskaya Bay and on the Shantar Islands.
Storms often roam the expanses of the Sea of Okhotsk. Particularly restless southern region seas, where strong winds blow from November to March, and wave crests rise to a height of 10-11 m. Another feature of this huge water basin is its efficiency, the largest in the Far East. Only off the western shores of Kamchatka and the Middle Kuril Islands does a strip of clean water. The destruction of the ice cover lasts from April to August - as you can see, our sea is called icy not by chance. The movement of air masses also affects the harsh nature of the Sea of Okhotsk. The winter anticyclone determines the northwestern direction of the winds, and in summer the southeastern winds prevail, which is typical for the monsoon climate. The amplitude of annual fluctuations in air temperature is 35°C, exceeding that in the Bering and Japan Seas by 10°. Average annual temperature air in the Sea of Okhotsk varies from -7° (in the Gizhigi region) to 5.5° (Abasiri in Hokkaido).
Summer heating of the waters of the Sea of Okhotsk is limited to: the uppermost layers. In August, the surface water temperature reaches 16-18° off the coast of Hokkaido and 12-14° C in the northwest. The lowest summer temperature of surface waters is kept along the Middle Kuriles (6-8°C) and near the Pyagin Peninsula (4-6°C). February (most cold month) negative temperatures prevail throughout the Sea of Okhotsk. The “permafrost” layer is what hydrologists call a water horizon lying at a depth of between 50 and 100 m. Off the coast of Sakhalin, the temperature of this water layer is the lowest and reaches -1.6 °. Deeper, about 200 m, the temperature rises again by 1.5-2° above zero. Only in the northern part of the sea and southeast of Sakhalin is this depth characterized by negative temperatures. With further immersion, the temperature slowly rises, reaching 2.4 ° at around 1000 m (due to warmer ocean waters), and then slightly decreases again. At depths of two to three thousand meters, it is 1.9 ° C in winter and summer.
In the area of the Kuril Islands, the salinity of the waters of the Sea of Okhotsk reaches 33 ppm (slightly more than 30 grams of salts in one liter). Salinity is lower elsewhere; the most desalinated water is in the Sakhalin Bay, where the Amur flows. With depth, the salinity of sea water increases, and below two thousand meters it is quite consistent with ocean water, reaching 34.5 ppm.
The maximum saturation of water with oxygen and the highest concentration of hydrogen ions were recorded at a depth of 10 m, which is associated with the intensive development of phytoplankton. At a depth of 1000-1500 m, a sharp oxygen deficiency was noted - up to 10% saturation. A zone of "biological depression" is formed here. Deeper, the oxygen content increases to 20-25%. Filled through the straits with oceanic waters with a low oxygen content, the Sea of Okhotsk basin contains water masses that mix weakly due to sharp differences in density between individual layers. The vertical circulation of water occurs within the first two hundred meter layer. This is due to the formation at a depth of 50-100 m of a denser and colder intermediate layer of water. Their winter cooling is accompanied by an increase in salinity and density, which leads to the sinking of these masses from the surface.
Differences in water salinity in the Amur Estuary can reach 22 ppm. From the north, salty sea waters enter the estuary, mixing with fresh river waters. With strong southerly winds, a countercurrent sometimes occurs in the Amur, salty water rises up its channel, and the so-called "faunistic barrier" is formed, which animals cannot overcome.
The bottom sediments of the Sea of Okhotsk are represented by sands, pebbles and stony placers with an admixture of silt on the shelf. In closed bays, separated from the sea by sandy spits, pure silts are deposited. Sandy sediments prevail in the Sakhalin Bay, and pebble - in the Penzhina Bay. In the deep basin in the south of the sea, the bottom is covered with sandy silts, and in the central part of it, greenish and brown silts at depths between 1000 and 3000 m determine the spread of the stagnant water zone. Around the island of Iona, at a depth of about 500 m, iron-manganese nodules were found.
The sediments contain many flint shells of the smallest unicellular organisms - diamote algae and radiolarians.
The history of the Sea of Okhotsk goes back hundreds of millions of years. Seaweeds and bacteria that existed over one and a half billion years ago left traces of their life activity on the western coast of the current Sea of Okhotsk. In the Silurian period (about 450 million years ago), southwestern part the modern basin of the Sea of Okhotsk and the region of Sakhalin Island. The same situation persisted in the Devonian (400-350 million years ago) in the region of the Shantar Islands, where even Coral reefs, or rather, reef-like communities with the participation of coral polyps, bryozoans, sea urchins and lilies. However, most of the basin in the Paleozoic rose above sea level. The ancient land of Okhotia located here about 220 million years ago included the central part of the current sea, Sakhalin and Kamchatka. From the north, west and south, Okhotia was washed by a rather deep sea with many islands. Finds of remains of ferns and cycadophytes indicate that subtropical flora grew here, which requires high temperatures and a humid climate.
Another 100 million years passed. In place of Sakhalin and Japanese islands stretched a huge chain of coral reefs, in size exceeding the current Great Barrier Reef in eastern shores Australia. The Jurassic reef system probably for the first time marked the position of the future island arc that separated the Sea of Japan from the Pacific Ocean. A major transgression flooded the entire Okhotia and adjacent land areas about 80 million years ago. On the site of Kamchatka, two parallel island ridges were born. As you approach modern era they extended more and more southbound, separating the basins of the Bering and Okhotsk Seas with another arc.
50-60 million years ago a sharp decline sea level led to the complete drying of Okhotia and Beringia. A great connoisseur of the ancient history of the Sea of Okhotsk, Professor G. U. Lindberg convincingly showed that Okhotia was even mountainous in places and large rivers flowed through its territory, starting far to the west - the Paleoamur and the Paleoopenzhina. They have developed deep canyons, which later became underwater depressions. Some forms of land relief and traces of ancient coastlines have been preserved at the bottom of the Sea of Okhotsk to this day.
Okhotia went under water about 10 thousand years ago, with the end of the last Quaternary glaciation. Over time, the South Okhotsk basin was separated from the Pacific Ocean by the youngest island arc of the Far East - the Kuril one - and the outlines of the Sea of Okhotsk were finally determined.
Centuries have passed. The first inhabitants appeared on the Okhotsk coast. The bays and estuaries of the sea abounded with seal rookeries, walruses entered its northern part. The ancient northerners were engaged in sea fishing, collecting edible mollusks and algae.
The significant similarity of the ancient cultures of the Koryaks, Aleuts and the indigenous inhabitants of Kodiak Island near Alaska, noted by the Siberian historian R.V. Vasilevsky, suggests that aborigines took part in the settlement of the New World, at least starting from the Neolithic, and maybe even earlier. Sea of Okhotsk and Kamchatka. This researcher found Proto-Aleutian features in the structure of Koryak harpoons, the shape of stone fat lamps-lamps and arrowheads, the characteristic type of tools with notched grooves, hooks, spears, awls, spoons and other hunting and household equipment.
In the south of the Sea of Okhotsk, there was an island culture, close in a number of ways to the ancient Koryak culture. We note the presence of a swivel harpoon and a significant number of seal and whale bones in the excavations, similar ceramics and stone inventory of the Amur settlements and sites of the ancient inhabitants of Sakhalin and the Kuril Islands.
The Soviet anthropologist M. G. Levin noted that “the anthropological, linguistic and cultural closeness of the Nivkhs of Sakhalin and Amur, which undoubtedly reflects the processes of constant communication between them over the past few centuries, at the same time, has its roots in the more distant past. - the Neolithic era ... It is likely that the Ainu legends about tons depict the ancestors of the Gilyaks or tribes related to them, whom the Ainu found on Sakhalin during their resettlement to this island ”(Ethnic Anthropology and Problems of Entogenesis of the Peoples of the Far East, M., 1958, p. 128 - 129).
But who are the Nivkhs, or Gilyaks, as these indigenous inhabitants of the Lower Amur and Sakhalin were recently called? The word "nivkh" means "man". Rites and customs, religious beliefs, myths and legends of the Nivkhs reflect the history of this ancient people of the Amur region and have long been the object of scientific research. Not so long ago, scientists were excited by the report of striking analogies in the language of the Nivkhs and some African tribes, in particular in Western Sudan. It also turned out that the dugout boats and axes of the Nivkhs are similar to the boats and axes of the inhabitants of the islands of Tahiti and the Admiralty.
What do these coincidences say? So far, it is difficult to answer this question. Maybe some thread will be drawn from the sacred chants of the Nivkhs?
The sea was seething. Seals and fish died.
There are no people, no fish.
Then a mountain was born from the sea.
Then the earth was born from the sea.
Does this legend testify that the Kuril Islands were born before the eyes of the Nivkhs? If we admit the possibility of such an interpretation of it, then we should recognize in the Nivkhs one of ancient peoples Far East. From the shamanic chant we learn about warm seas and white mountains, white sand shoals and abandoned Nivkh wives. Apparently, it is about coral islands the Pacific Ocean, from where the ancestors of the Nivkhs could come to the basin of the Sea of \u200b\u200bOkhotsk.
Even more mysterious is the story of the Ainu, who suddenly appeared among the natives of Sakhalin. As early as 1565, the monk de Froes reported in Japanese Letters: “... the Ainu are almost European appearance and thick hair covering the head ... differed sharply from the beardless Mongoloids. Their militancy, endurance, the custom of women to blacken their lips, nakedness, barely covered by the "belt of shame" so common among the southern islanders of the Pacific Ocean - all this was so amazing to travelers that some of them even called the Ainu black people. Vasily Poyarkov's "interrogative speeches" speak of an island lying to the east (i.e., Sakhalin), about the Nivkhs inhabiting its northern part, and "black people, who are called Kuy", living in the south. Local historians discovered the parking lot of Negroins in Petropavlovsk-Kamchatsky already today.
According to the outstanding Soviet scientist L. Ya. Sternberg, the peculiarities of the culture and anthropology of the Ainu bring them closer to some peoples of South India, Oceania and even Australia. One of the arguments in favor of the theory of the Austronesian origin of the Ainu is the cult of the snake, which is also common among some tribes of Southeast Asia.
When in the II millennium BC. e. Ainu came to southern islands Sea of Okhotsk, they found thin here. According to the legends, they were sea hunters and fishermen.
The conclusion suggests itself that the peoples who once inhabited the southern archipelagos of the Pacific Ocean, India and even Australia rolled into the Sea of Okhotsk region in waves. partly mixed with local population they adopted its culture and customs. typical inhabitants southern countries, the Ainu borrowed the canoe design from the Itelmens of Kamchatka, the type of boat from the Tonchi of Sakhalin, and winter clothes from the Nivkhs. Even in Ainu ornaments, as R. V. Kozyreva writes (Ancient Sakhalin, L., 1967), on ceramics and bone products, there are simple and geometric patterns and incisions characteristic of the early periods of the history of local culture.
Already before the eyes of man, the formation of the modern coastline of the Sea of Okhotsk continued. Even in new and modern times its level did not remain constant. Just 200 years ago, according to the Khabarovsk paleogeographer L. I. Sverlova, Sakhalin was connected with the mouth of the Amur. According to her calculations, based on the establishment of a functional relationship between fluctuations in the level of the World Ocean and changes temperature regime Earth, the lowest standing of sea waters accounted for 1710-1730. Comparing these data with the dates of the voyages of famous sailors, L.I. Sverlova came to the conclusion that J.F. Laieruz in 1787, W.R. Broughton in 1797, and even I.F. could pass through the Tatar Strait, because it did not exist at all: Sakhalin was a peninsula in those years.
In 1849-1855, during the period of the Amur expedition, sea waters had already blocked the bridge between the mainland and Sakhalin, and this allowed G. I. Nevelsky to convey to N. N. Muravyov: “Sakhalin is an island, the entrance to the estuary and the Amur River is possible for seagoing ships from the north and south. The age-old delusion has been positively dispelled, the truth has been revealed” (B.V. Struve. Memories of Siberia 1848-1854, St. Petersburg, 1889, p. 79).
And yet, L. I. Sverlova, apparently, overestimates the real significance of ocean level fluctuations. Without a shadow of a doubt, she writes, for example, that in 1849-1855. this level was 10 m higher than the present level. But where, then, are the marine sediments, terraces, abrasion areas, and many other features that inevitably accompany displacements of coastlines? The only proof higher level of the Far Eastern seas in the post-glacial period - a low terrace 1-3 m high, the remains of which were found in many places. However, the time of its formation is several thousand years from our days.
The Sea of Okhotsk is located between the waters of the Sea of Japan and the Bering Sea.
This body of water limits the territory of Japan and Russian Federation and is the most important port point on the map of our country.
Previously, among the names of the sea were Lamskoe, Kamchatskoe, and the Japanese - Hokkai, i.e. North.
Shores of the Sea of Okhotsk
This reservoir is considered to be one of the largest and deepest in Russia, as well as the coolest Far Eastern sea. The area of the water area is 1603 km 2, and the depth is over 800 m on average. The maximum depth indicator is almost 4 thousand meters. The coastal boundary of the reservoir is quite even, several bays pass along it. However, in the northern part of the waters there are many rocks and sharp cliffs. For the territory of this sea, storm warnings are completely normal.
The sea is separated from the Pacific Ocean by the Kuriles. We are talking about 3 dozen small areas of land that are in a seismically hazardous zone due to the abundance of volcanoes. Also, the waters of the Pacific Ocean and the Sea of Okhotsk are separated by Kamchatka and the island of Hokkaido. And the most large island this area - Sakhalin. Some straits of the reservoir act as a conditional border with the Sea of Japan. Among the largest rivers flowing into the sea, it is worth noting the Amur, Bolshaya, Penzhina, Okhota.
Cities on the Sea of Okhotsk
The main ports and cities of the Okhotsk water area include:
- Ayan, Okhotsk and Magadan on the mainland;
- Korsakov on Sakhalin Island;
- Severo-Kurilsk on the Kuril Islands.
Fisheries of the Sea of Okhotsk
(Private fishing: fishing on the shores of the Sea of Okhotsk, which is allowed only in open season fishing, but certain species, such as crab, require a permit, otherwise it may be considered poaching)
The natural resources of this northern sea are very diverse. Fishing, production of salmon caviar and seafood are actively developing on the territory of the reservoir. Famous inhabitants of these regions are pink salmon, sockeye salmon, cod, chum salmon, coho salmon, flounder, chinook salmon, herring, crabs and squids, pollock, navaga. In addition, there is limited fur seal hunting in the Shantar Islands. Now also popular is the extraction of shellfish, sea urchins and kelp.
(Fishing boat in the Sea of Okhotsk)
Industry in the Sea of Okhotsk began to develop in the 90s. First of all, we are talking about ship repair factories and fish processing enterprises on Sakhalin. The development of hydrocarbon raw materials is also carried out in the Sakhalin region. Currently, 7 points with oil deposits have been discovered in the sea area, which began to be developed back in the 70s. last century.
The area of the Sea of Okhotsk is 1.603 million square meters. km. Average depth 1780 m maximum depth 3521 m. The western part of the sea has a shallow depth and is located on the continental shelf. In the center of the sea are the Deryugin depressions (in the south) and the TINRO depression. In the eastern part there is the Kuril basin, in which the depth is maximum.
From October to May-June, the northern part of the sea is covered with ice. southeastern part practically does not freeze.
The coast in the north is strongly indented, in the northeast of the Sea of Okhotsk there is its largest bay - Shelikhov Bay. Of the smaller bays of the northern part, the most famous are the Eyriney Bay and the bays of Shelting, Zabiyak, Babushkin, Kekurny, Odessa Bay on Iturup Island. In the east, the coastline of the Kamchatka Peninsula is practically devoid of bays. In the southwest, the largest are Aniva and Patience bays.
Fishing (salmon, herring, pollock, capelin, navaga, etc.).
Main ports: on the mainland - Magadan, Ayan, Okhotsk (portpoint); on the island of Sakhalin - Korsakov, on the Kuril Islands - Severo-Kurilsk.
The Sea of Okhotsk is named after the Okhot River, which in turn comes from the Even okat - "river". The Japanese traditionally called this sea "Hokkai" (北海), literally "North Sea". But since this name now refers to North Sea Atlantic Ocean, they changed the name of the Sea of Okhotsk to "Ohotsuku-kai" (オホーツク海), which is an adaptation of the Russian name to the norms of Japanese phonetics.
The sea is located on the Okhotsk subplate, which is part of the Eurasian plate. The crust under most of the Sea of Okhotsk is of continental type.
Separated by conditional boundaries. The Sea of Okhotsk is a fairly large and deep sea in our country. Its area is about 1603 thousand km2, the volume of water is 1318 thousand km3. The average depth of this sea is 821 m, the maximum depth is 3916 m. According to its features, this sea is a marginal sea of a mixed continental-marginal type.
There are few islands in the waters of the Sea of Okhotsk, among which the largest is. The Kuril ridge consists of 30 different in size. Their location is seismically active. There are more than 30 active and 70 extinct ones here. Seismic activity zones can be located both on islands and under water. If the epicenter is under water, then huge ones rise.
The coastline of the Sea of Okhotsk, with a considerable length, is quite equal. There are many large bays along the coastline: Aniva, Patience, Sakhalin, Academies, Tugursky, Ayan and Shelikhov. There are also several lips: Tauiskaya, Gizhiginskaya and Penzhinskaya.
Sea of Okhotsk
The bottom is a wide range of different underwater elevations,. The northern part of the sea is located on the continental shelf, which is a continuation of the land. In the western zone of the sea there is a shoal of Sakhalin, located near the island. In the east of the Sea of Okhotsk is Kamchatka. Only a small part is located in the shelf zone. A significant part of the water expanses is located on the continental slope. The depth of the sea here varies from 200 m to 1500 m.
The southern edge of the sea is the deepest zone, the maximum depth here is more than 2500 m. This part of the sea is a kind of bed, which is located along the Kuril Islands. The southwestern part of the sea is characterized by deep depressions and slopes, which is not characteristic of the northeastern part.
In the central zone of the sea there are two hills: the Academy of Sciences of the USSR and the Institute of Oceanology. These elevations divide the sea underwater space into 3 basins. The first basin is the northeastern TINRO basin, which is located to the west of Kamchatka. This depression is distinguished by small depths, about 850 m. The bottom has. The second basin is the Deryugin depression, located to the east of Sakhalin, the water depth here reaches 1700 m. The bottom is a plain, the edges of which are somewhat elevated. The third basin is the Kuril. It is the deepest (about 3300 m). is a plain that extends 120 miles in the western part, and 600 miles in the northeast.
The Sea of Okhotsk is influenced by the monsoon climate. The main source of cold air is located in the west. This is due to the fact that the western part of the sea is strongly cut into the mainland and is located not far from the Asian cold pole. From the east, the relatively high mountain ranges of Kamchatka impede the advance of the warm Pacific. The greatest amount of heat comes from the waters of the Pacific Ocean and the Sea of Japan through the southern and southeastern borders. But the influence of cold air masses dominates over warm air masses, therefore, in general, the Sea of Okhotsk is quite severe. The Sea of Okhotsk is the coldest in comparison with the Sea of Japan.
Sea of Okhotsk
During the cold period (which lasts from October to April), the Siberian and Aleutian lows have a significant effect on the sea. As a result, winds from the northern and northwestern directions prevail in the Sea of Okhotsk. The power of these winds often reaches storm strength. Especially strong winds seen in January and February. Their average speed is about 10 - 11 m/s.
In winter, the cold Asian monsoon contributes to a strong decrease in the northern and northwestern parts of the sea. In January, when the temperature reaches its minimum limit, on average the air cools down to -20-25°C in the northwestern part of the sea, to -10-15°C in the central part and to -5-6°C in the southeastern part. In the last zone, the influence of warm Pacific air is felt.
In autumn and winter, the sea is under the influence of continental. This leads to increased wind, and in some cases to cooling. In general, it can be described as clear with reduced. These climatic features are influenced by cold Asian air. In April-May, the Siberian anticyclone ceases to operate, and the influence of the Honolulu maximum increases. In this regard, during the warm period, small southeast winds are observed, the speed of which rarely exceeds 6–7 m/s.
In summer, there are different temperatures depending on. In August, the highest temperature is recorded in the southern part of the sea, it is +18°С. In the central part of the sea, the temperature drops to 12-14°C. The northeast has the coldest summer, the average temperature does not exceed 10-10.5°C. During this period, the southern part of the sea is subject to numerous oceanic cyclones, due to which the wind strength increases, and storms rage for 5-8 days.
Sea of Okhotsk
A large number of rivers carry their waters to the Sea of Okhotsk, but they are all mostly small. In this regard, it is small, it is about 600 km 3 during the year. , Penzhina, Okhota, Bolshaya - the largest flowing into the Sea of \u200b\u200bOkhotsk. Fresh waters have little effect on the sea. The waters of the Sea of Japan and the Pacific Ocean have great importance for the Sea of Okhotsk.
