This natural reservoir is considered one of the deepest and largest in Russia. The coolest Far Eastern sea is located between the waters of the Bering and the Sea of Japan.
The Sea of Okhotsk separates the territories of the Russian Federation and Japan and represents the most important port point for our country.
After reviewing the information in the article, you can learn about the richest resources of the Sea of Okhotsk and the history of the formation of the reservoir.
About the name
Previously, the sea had other names: Kamchatskoe, Lamskoe, Hokkai among the Japanese.
The current name of the sea was given by the name of the Okhota River, which in turn comes from the Even word "okat", which translates as "river". The former name (Lamskoe) also came from the Even word "lam" (translated as "sea"). Hokkai literally translates to "North Sea" in Japanese. However, due to the fact that this Japanese name now refers to the North Atlantic Ocean, its name was changed to Ohotsuku-kai, which is an adaptation of the Russian name to the norms of Japanese phonetics.
Geography
Before proceeding to the description of the richest resources of the Sea of Okhotsk, we briefly present its geographical position.
The reservoir, located between the Bering and the Seas of Japan, strongly goes into the land of the mainland. The arc of the Kuril Islands separates the waters of the sea from the waters of the Pacific Ocean. The reservoir has for the most part natural boundaries, and its conditional boundaries are with the Sea of Japan.
The Kuriles, which are about 3 dozen small areas of land and separating the ocean from the sea, are located in a seismically hazardous zone due to the presence of a large number of volcanoes on them. In addition, the waters of these two natural reservoirs are separated by the island of Hokkaido and Kamchatka. The largest island in the Sea of Okhotsk is Sakhalin. The largest rivers flowing into the sea are Amur, Okhota, Bolshaya and Penzhina.
Description
The area of the sea is approximately 1603 thousand square meters. km, the volume of water - 1318 thousand cubic meters. km. The maximum depth is 3916 meters, the average is 821 m. The type of sea is mixed, continental-marginal.
Several bays pass along the rather even coastal boundary of the reservoir. The northern part of the coast is represented by many rocks and rather sharp cliffs. Storm is a frequent and quite common occurrence for this sea.
Features of nature and all resources of the Sea of Okhotsk are partly related to climate conditions and unusual terrain.
For the most part, the seashores are rocky and high. From the sea, from afar, on the horizon, they are distinguished by black stripes, framed on top by brownish green spots of sparse vegetation. Only in some places (the western coast of Kamchatka, the northern part of Sakhalin), the coastline is low, fairly wide areas.
The bottom in some respects is similar to the bottom of the Sea of Japan: in many places there are hollows under water, which indicate that the area of \u200b\u200bthe present sea in the Quaternary period was above sea level, and huge rivers flowed in this place - Penzhina and Amur.
Sometimes, during earthquakes, waves appear in the ocean, reaching several tens of meters in height. One interesting historical fact is connected with this. In 1780, one of these waves during an earthquake deep into the island of Urup (300 meters from the coast) brought the ship "Natalia", which remained on land. This fact is confirmed by the record preserved from those times.
Geologists believe that the territory of the eastern part of the sea is one of the most "troubled" areas on the globe. And today quite large movements of the earth's crust are taking place here. In this part of the ocean, underwater earthquakes and volcanic eruptions are often observed.
A little bit of history
The rich natural resources of the Sea of Okhotsk began to attract the attention of people from its very discovery, which occurred during the first campaigns of the Cossacks to the Pacific Ocean through Siberia. It was then called the Lam Sea. Then, after the discovery of Kamchatka, trips by sea and coast to this richest peninsula and to the mouth of the river. Penzhins have become more frequent. In those days, the sea already bore the names Penzhinskoe and Kamchatskoe.
After leaving Yakutsk, the Cossacks moved east not straight through the taiga and mountains, but along the winding rivers and channels between them. Such a caravan path eventually led them to a river called the Hunt, and along it they were already moving to the seashore. That is why this reservoir was named Okhotsk. Since then, many significant and important large centers have arisen on the sea coast. The name that has been preserved since then testifies to the important historical role of the port and the river, from which people began the development of this vast, richest sea area.
Features of nature
The natural resources of the Sea of Okhotsk are quite attractive. This is especially true for the regions of the Kuril Islands. This is a very special world, consisting of a total of 30 large and small islands. This range also includes rocks of volcanic origin. Today, there are active volcanoes on the islands (about 30), which clearly indicates that the bowels of the earth are restless here and now.
Some islands have underground hot springs (temperature up to 30-70°C), many of which have healing properties.
Very severe climatic conditions for life on the Kuril Islands (especially in the northern part). Fogs are kept here for a long time, and in winter very often there are strong storms.
Rivers
Many rivers, mostly small ones, flow into the Sea of Okhotsk. This is the reason for the relatively small continental flow (about 600 cubic km per year) of water into it, and about 65% of it belongs to the Amur River.
Other relatively large rivers are the Penzhina, Uda, Okhota, Bolshaya (in Kamchatka), which carry a much smaller volume of fresh water into the sea. Water flows to a greater extent in spring and early summer.
Fauna
The biological resources of the Sea of Okhotsk are very diverse. This is the most biologically productive sea in Russia. It provides 40% of domestic and more than half of the Far Eastern catches of fish, crustaceans and mollusks. At the same time, it is believed that the biological potential of the sea is underutilized today.
A huge variety of depths and bottom topography, hydrological and climatic conditions in certain parts of the sea, a good supply of fish food - all this led to the richness of the ichthyofauna of these places. The northern part of the sea contains 123 species of fish in its waters, the southern part - 300 species. Approximately 85 species are endemic. This sea is a real paradise for lovers of sea fishing.
Fishing, seafood production and production of salmon caviar are actively developing on the territory of the sea. The inhabitants of the sea waters of this region: pink salmon, chum salmon, cod, sockeye salmon, flounder, coho, pollock, herring, saffron cod, chinook salmon, squid, crabs. On the Shantar Islands, hunting (limited) for fur seals is carried out, and the extraction of kelp, mollusks and sea urchins is also becoming popular.
Of the animals, the white whale, seal and seal are of particular commercial value.
Flora
The resources of the Sea of Okhotsk are inexhaustible. The flora of the reservoir: Arctic species predominate in the northern part, and species from the temperate region predominate in the southern part. Plankton (larvae, mollusks, crustaceans, etc.) provides abundant food for fish throughout the year. The phytoplankton of the sea is represented mainly by diatoms, and the bottom flora contains many species of red, brown and green algae, as well as extensive meadows of sea grass. In total, the composition of the coastal flora of the Sea of Okhotsk includes about 300 species of vegetation.
In comparison with the Bering Sea, the benthic fauna here is more diverse, and in comparison with the Sea of Japan, it is less rich. The main food fields for deep-sea fish are the northern shallow waters, as well as the East Sakhalin and western Kamchatka shelves.
Mineral resources
The mineral resources of the Sea of Okhotsk are especially rich. Only the water of the sea contains almost all the elements of the table of D. I. Mendeleev.
The bottom of the sea has exceptional reserves of globigerin and diamond silts, consisting mainly of shells of unicellular tiny algae and protozoa. Sludge is a valuable raw material for the production of insulating building materials and high quality cement.
The shelf of the sea is also promising for prospecting for hydrocarbon deposits. The rivers of the Aldan-Okhotsk watershed and the lower reaches of the Amur have long been famous for placers of valuable metals, which indicates that there is a possibility of finding underwater ore deposits in the sea. Perhaps there are still many unexplored raw materials in the Sea of Okhotsk.
It is known that the lower shelf horizons and part of the continental slope adjoining them are enriched in phosphorite concretions. There is another more realistic prospect - the extraction of rare elements contained in the bone remains of mammals and fish, and such accumulations are found in deep-sea sediments of the Yuzhno-Okhotskaya basin.
It is impossible to remain silent about amber. The very first finds of this mineral on the eastern coast of Sakhalin date back to the middle of the 19th century. At that time, representatives of the Amur expedition worked here. It should be noted that Sakhalin amber is very beautiful - it is perfectly polished, cherry-red and highly appreciated by specialists. The largest pieces of wood fossil resin (up to 0.5 kg) were discovered by geologists near the village of Ostromysovsky. Amber is also found in the oldest deposits of the Taigonos Peninsula, as well as in Kamchatka.
Conclusion
In short, the resources of the Sea of Okhotsk are extremely rich and diverse, it is impossible to list all of them, let alone describe them.
Today, the importance of the Sea of Okhotsk in the national economy is determined by the use of its richest natural resources and sea transportation. The main wealth of this sea are game animals, primarily fish. However, already today, a rather high level of danger of pollution of the sea fishing zones with oil products as a result of discharges of oily waters by fishing vessels creates a situation that requires certain measures to increase the level of environmental safety of the work being carried out.
The Sea of Okhotsk is located in the northwestern part of the Pacific Ocean off the coast of Asia and is separated from the ocean by the chain of the Kuril Islands and Kamchatka. From the south and west, it is bounded by the coast of Hokkaido, the eastern coast of Sakhalin Island and the coast of the Asian mainland. The sea is significantly elongated from southwest to northeast within a spherical trapezoid with coordinates 43°43"–62°42" N. sh. and 135°10"–164°45"E. e. The greatest length of the water area in this direction is 2463 km, and the width reaches 1500 km. The surface area of the sea surface is 1603 thousand km2, the length of the coastline is 10460 km, and the total volume of sea water is 1316 thousand km3. According to its geographical location, it belongs to the marginal seas of the mixed continental-marginal type. The Sea of Okhotsk is connected with numerous straits of the Kuril Islands, and with the Sea of Japan - through the La Perouse Strait and through the Amur Estuary - the Nevelsky and Tatar Straits. The average value of the sea depth is 821 m, and the largest is 3521 m (in the Kuril basin).
The main morphological zones in are: the shelf (the mainland and insular shallows of Sakhalin Island), the continental slope, on which separate underwater heights, depressions and islands stand out, and. The shelf zone (0–200 m) is 180–250 km wide and occupies about 20% of the sea area. Wide and gentle, in the central part of the basin, the continental slope (200–2000 m) occupies about 65%, and the deepest basin (more than 2500 m), located in the southern part of the sea, occupies 8% of the sea area. Within the area of the continental slope, several elevations and depressions are distinguished, where the depths change dramatically (the uplift of the Academy of Sciences, the uplift of the Institute of Oceanology and the Deryugin Basin). The bottom of the deep-water Kuril Basin is a flat abyssal plain, and the Kuril Ridge is a natural threshold separating the sea basin from the ocean.
The Amur Estuary, Nevelskoy in the north and Laperouse in the south straits connect the Sea of Okhotsk with the Sea of Japan, and the numerous Kuril Straits with the Pacific Ocean. The chain of the Kuril Islands is separated from the island of Hokkaido by the Strait of Treason, and from the Kamchatka Peninsula by the First Strait. The straits connecting the Sea of Okhotsk with the adjacent areas of the Sea of Japan and the Pacific Ocean provide the possibility of water exchange between the basins, which, in turn, have a significant impact on the distribution of hydrological characteristics. The Nevelskoy and La Perouse straits are relatively narrow and shallow, which is the reason for the relatively weak water exchange with the Sea of Japan. The straits of the Kuril Islands, which stretch for about 1200 km, on the contrary, are deeper, and their total width is 500 km. The deepest are the Bussol Straits (2318 m) and (1920 m).
The northwestern coast of the Sea of Okhotsk is practically devoid of large bays, while the northern coast is significantly indented. The Tauiskaya Bay protrudes into it, the coasts of which are indented with bays and bays. The bay is separated from the Sea of Okhotsk by the Koni Peninsula.
The largest bay of the Sea of Okhotsk lies in its northeastern part, extending 315 km into the mainland. This is Shelikhov Bay with Gizhiginskaya and Penzhinskaya lips. The Gizhiginskaya and Penzhinskaya bays are separated by the elevated Taigonos Peninsula. In the southwestern part of Shelikhov Bay, north of the Pyagin Peninsula, there is a small Yamskaya Bay.
The western coast of the Kamchatka Peninsula is leveled and practically devoid of bays.
The shores of the Kuril Islands are complex in outline and form small bays. On the Sea of Okhotsk side, the largest bays are located near Iturup Island, which are deep-water and have a very intricately dissected bottom. 
Quite a lot mainly flows 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 km3 per year, while about 65% of the flow comes from the Amur River. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring significantly 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.
The shores of the 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 on the Kamchatka Peninsula and Sakhalin Island are 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 southeast is low, and the northeast is low. The shores of the Kuril Islands are very steep. The northeastern coast of Hokkaido is predominantly low-lying. The coast of the southern part of Western Kamchatka has the same character, but the shores of its northern part are somewhat elevated.
According to the features of the composition and distribution of bottom sediments, three main zones can be distinguished: the central zone, which is composed mainly of diatomaceous silt, silty-argillaceous and partially clayey oozes; the distribution zone of hemipelagic and pelagic clays in the western, eastern and northern parts of the Sea of Okhotsk; as well as the distribution zone of inequigranular sands, gravel sandstones and silts - in the northeast of the Sea of Okhotsk. Coarse clastic material, which is the result of ice rafting, is ubiquitous.
The Sea of Okhotsk is located in the zone. 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, 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.
In the cold part of the year (from October to April), the Aleutian Low also influences 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 northwesterly and northerly winds, often reaching storm strength. In winter, the wind speed is usually 10–11 m/s.
In the coldest month - January - the average air temperature in the north-west of the sea is –20…–25°С, in the central regions - –10…–15°С, and in the south-eastern part of the sea - –5…–6° WITH.
In autumn and winter, cyclones are predominantly of continental origin. 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 destroyed, and the Hawaiian maximum is strengthened. 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 located above. At the same 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 to the northeast (from 18°C to 10–10.5°C).
In the warm season, tropical cyclones quite often pass over the southern part of the sea -. They are associated with an increase in wind to a storm, which can last up to 5–8 days. The predominance of southeastern winds in the spring-summer season leads to significant, precipitation, .
Monsoon winds and stronger winter cooling of the western part of the Sea of Okhotsk compared to the eastern part are important climatic features of this sea.
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 that most significantly affect the formation of the hydrological conditions of the Sea of Okhotsk.
The flow of surface Pacific waters into the Sea of Okhotsk occurs mainly through the northern straits, in particular through the First Kuril Strait.
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.
The influx of Pacific waters significantly affects the distribution of temperature, salinity, and the formation of the structure and waters of the Sea of Okhotsk.
The following water masses are distinguished in the Sea of Okhotsk:
- surface, having spring, summer and autumn modifications. It is a thin heated layer 15–30 m thick, which limits the upper stability maximum, which is mainly determined by temperature;
- 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 occurring between horizons of 40–150 m. This water mass is characterized by a rather uniform (31–32‰) and different temperature;
- the intermediate water mass is formed mainly due to the descent of water along the underwater slopes within the sea, ranging from 100–150 to 400–700 m, and is characterized by a temperature of 1.5°C and a salinity of 33.7‰. This water mass is distributed almost everywhere;
- the deep Pacific water mass is the water of the lower part of the warm layer of the Pacific Ocean, entering the Sea of Okhotsk at horizons below 800–1000 m. This water mass is located at horizons of 600–1350 m, has a temperature of 2.3 ° C and a salinity of 34.3‰ .
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. This water mass fills the basin from the horizon of 1350 m to the bottom and is characterized by a temperature of 1.85 ° C and a salinity of 34.7 change only slightly with depth.
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°C. Only in the southeastern part of the sea does it stay around 0°C, and near the northern Kuril Straits, under the influence of Pacific waters, the water temperature reaches 1–2°C.
Spring warming at the beginning of the season mainly goes to the melting of ice, only towards the end of it does it begin to rise.
In summer, the distribution of water temperature on the sea surface is quite diverse. In August, the waters adjacent to the island of Hokkaido are warmest (up to 18–19°C). In the central regions of the sea, the water temperature is 11–12°С. The coldest surface waters are observed near Iona Island, near Cape Pyagin and near the Kruzenshtern Strait. In these areas, the water temperature is kept in the range of 6-7°C. 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 ° С on the surface to -0.25 ° С at horizons of 500-600 m , deeper it rises to 1–0°C, in the southern part of the sea and near the Kuril Straits, the water temperature drops from 2.5–3°C on the surface to 1–1.4°C at 300–400 m horizons and then gradually rises up to 1.9–2.4°С in the bottom layer.
In summer, surface waters are warmed up to a temperature of 10–12°С. In the subsurface layers, the water temperature is slightly lower than on the surface. A sharp drop in temperature to –1…–1.2°C is observed between horizons of 50–75 m, deeper, to horizons of 150–200 m, the temperature quickly rises to 0.5–1°C, and then it rises more smoothly, and at the horizons of 200–250 m it is 1.5–2°С. 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°C at the surface to 3–8°C at 25 m, then to 1.6–2.4°C at a horizon of 100 m and up to 1.4–2°C 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 it is 31–32‰ and more (up to 33‰ near the Kuril ridge).
In the northwestern part of the sea, due to freshening, the salinity on the surface is 25‰ or less, and the thickness of the freshened 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 individual bays and straits, salinity and its stratification may differ significantly from the waters of the open sea, 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, a noticeable vertical density stratification of waters is created; the density increases especially noticeably at horizons of 25–50 m, which is associated with warming of waters in open areas and desalination near the coast.
Intense ice formation over most of the sea excites an enhanced thermohaline winter vertical circulation. At depths up to 250–300 m, it propagates to the bottom, and below it is prevented by the maximum stability that exists here. In areas with a broken bottom, the spread of density mixing into the lower horizons is facilitated by the sliding of water along the slopes.
Under the influence of winds and water inflow through the Kuril Straits, characteristic features of the system of non-periodic currents of the Sea of Okhotsk are formed. 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 can be traced in the sea.
Strong currents bypass the sea along the coastline against: the warm Kamchatka current, the stable East Sakhalin current and the rather strong Soya current.
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.
The currents on the surface of the Sea of Okhotsk are most intense in the western (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 Kuril Basin (11–20 cm/s) and during the Soya (up to 50–90 cm/s).
In the Sea of Okhotsk, various types of periodic tidal currents are well expressed: 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 low - 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.
In general, level fluctuations in the Sea of Okhotsk are very significant and have a significant impact on its hydrological regime, especially in the coastal zone.
In addition to tidal fluctuations, surge fluctuations in the level are also well developed here. They occur mainly when passing deep 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.
The significant size and great depths of the Sea of Okhotsk, frequent and strong winds over it determine the development of large waves here. The sea is especially stormy in autumn, and in some areas even 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%.
In ordinary years, the southern boundary of the relatively stable ice cover curves northward 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.
The ice cover in the Sea of Okhotsk lasts for 6-7 months. Floating ice covers more than 75% of the sea surface. Close-packed 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. Part of the ice from the Sea of Okhotsk is carried into the ocean, where it breaks up and melts almost immediately.
The forecast hydrocarbon resources of the Sea of Okhotsk are estimated at 6.56 billion tons of oil equivalent, proven reserves are over 4 billion tons. The largest deposits are on the shelves (along the coast of Sakhalin Island, the Kamchatka Peninsula, Khabarovsk Territory and the Magadan Region). The deposits of Sakhalin Island are the most studied. Exploration work on the shelf of the island began in the 70s. XX century., By the end of the 90s, seven large fields (6 oil and gas condensate and 1 gas condensate) and a small gas field were discovered on the shelf of North-Eastern Sakhalin. The total gas reserves on the Sakhalin shelf are estimated at 3.5 trillion m3.
The flora and fauna are very diverse. In terms of stocks of commercial crab, the sea ranks first in the world. Salmon fish are of great value: chum salmon, pink salmon, coho salmon, chinook, sockeye - a source of red caviar. Intensive fishing is carried out for herring, pollock, flounder, cod, navaga, capelin, etc. Whales, seals, sea lions, fur seals live in the sea. The fishing of mollusks and sea urchins is gaining more and more interest. Various algae are ubiquitous in the littoral.
Due to the poor development of the adjacent territories, maritime transport has become of primary importance. Important sea routes lead to Korsakov on Sakhalin Island, Magadan, Okhotsk and other settlements.
The areas of the Tauiskaya Bay in the northern part of the sea and the shelf areas of Sakhalin Island are subjected to the greatest anthropogenic load. About 23 tons of oil products enter the northern part of the sea annually, with 70–80% of c. Pollutants enter the Tauyskaya Bay from coastal industrial and municipal facilities, and they enter the coastal zone practically without treatment.
The shelf zone of Sakhalin Island is polluted by coal, oil and gas production enterprises, pulp and paper mills, fishing and processing vessels and enterprises, and sewage from municipal facilities. The annual flow of oil products into the southwestern part of the sea is estimated at about 1.1 thousand tons, with 75–85% coming from river runoff.
Petroleum hydrocarbons enter the Sakhalin Bay mainly with runoff, so their maximum concentrations, as a rule, are noted in the central and western parts of the bay along the axis of the incoming Amur waters.
The eastern part of the sea - the shelf of the Kamchatka Peninsula - is polluted by river runoff, with which the main part of petroleum hydrocarbons enters the marine environment. In connection with the reduction of work at the fish canning enterprises of the peninsula since 1991, there has been a decrease in the volume of wastewater discharged into the coastal zone of the sea.
The northern part of the sea - Shelikhov Bay, Tauyskaya and Penzhinskaya bays - is the most polluted area of the sea with an average content of petroleum carbons in water 1–5 times higher than the permissible concentration limit. This is determined not only by the anthropogenic load on the water area, but also by the low average annual water temperatures and, consequently, the low ability of the ecosystem to self-purify. The highest level of pollution in the northern part of the Sea of Okhotsk was noted in the period from 1989 to 1991.
The southern part of the sea - the La Perouse Strait and the Aniva Bay - are subjected to intense oil pollution in the spring-summer period by commercial and fishing fleets. On average, the content of petroleum hydrocarbons in the La Perouse Strait does not exceed the limit of permissible concentration. Aniva Bay is slightly more polluted. The highest level of pollution in this area was noted near the port of Korsakov, once again confirming that the port is a source of intense pollution of the marine environment.
Pollution of the coastal zone of the sea along the northeastern part of Sakhalin Island is mainly associated with exploration and production on the shelf of the island and did not exceed the maximum permissible concentration until the end of the 1980s.
The Sea of Okhotsk is one of the largest and deepest seas in Russia. Important sea routes connect Vladivostok with the northern regions of the Far East and the Kuril Islands. Large ports on the mainland coast are Magadan and Okhotsk; on the island of Sakhalin - Korsakov; on the Kuril Islands - Severo-Kurilsk.
The Sea of Okhotsk was discovered by Russian explorers I. Yu. Moskvitin and V. D. Poyarkov in the first half of the 17th century. In 1733, work began on the Second Kamchatka Expedition, whose participants compiled detailed maps of almost all of its shores.
The Sea of Okhotsk, also called the Lama or Kamchatka Sea, is a semi-enclosed sea in the northwestern part of the Pacific Ocean. It washes the shores of Russia and Japan (Hokkaido Island).
From the west it is limited by the continent of Asia from Cape Lazarev to the mouth of the Penzhina River; from the north - the Kamchatka Peninsula; from the east by the islands of the Kuril ridge and from the south by the islands of Hokkaido and Sakhalin.
The Sea of Okhotsk is connected to the Pacific Ocean through the Kuril Straits system. There are more than 30 such straits and their total width is more than 500 kilometers. It communicates with the Sea of Japan through the Nevelskoy and La Perouse straits.
Characteristics of the Sea of Okhotsk
The sea is named after the Okhota River flowing into it. The area of the Sea of Okhotsk is 1,603,000 square kilometers. Its average depth is 1780 meters, with a maximum depth of 3916 meters. From north to south the sea stretches for 2445 kilometers, and from east to west for 1407 kilometers. The approximate volume of water contained in it is 1365 thousand cubic kilometers.
The coastline of the Sea of Okhotsk is slightly indented. Its length is 10,460 kilometers. Its largest bays are considered to be: Shelikhov Bay, Sakhalin Bay, Udskaya Bay, Tauiskaya Bay and Academy Bay. The northern, northwestern and northeastern shores are high and rocky. At the confluence of large rivers (Amur, Uda, Okhota, Gizhiga, Penzhina), as well as in the west of Kamchatka, in the northern part of Sakhalin and Hokkaido, the banks are predominantly low-lying.
From October to May-June, the northern part of the sea is covered with ice. The southeastern part practically does not freeze. In winter, the water temperature at the sea surface ranges from −1.8 °C to 2.0 °C; in summer, the temperature rises to 10-18 °C.
The salinity of the surface waters of the Sea of Okhotsk is 32.8–33.8 ppm, and the salinity of coastal waters usually does not exceed 30 ppm.
Climate of the Sea of Okhotsk
The Sea of Okhotsk is located in the monsoon climate zone of temperate latitudes. For most of the year, cold, dry winds blow from the mainland, cooling the northern half of the sea. From October to April, negative air temperatures and stable ice cover are observed here.
In the northeastern part of the sea, the average temperature in January - February ranges from - 14 to - 20 ° C. In the northern and western regions, the temperature varies from - 20 to - 24 ° C. In the southern and eastern parts of the sea, winter is much warmer from - 5 up to - 7° C.
Average temperatures in July and August, respectively, are 10-12 ° C; 11-14° C; 11-18° C. The annual amount of precipitation in different places of the Sea of Okhotsk is also different. Thus, in the north, 300-500 mm of precipitation falls per year; in the west up to 600-800 mm; in the southern and southeastern parts of the sea - over 1000 mm.
In terms of the composition of organisms living in the Sea of Okhotsk, it is more arctic in nature. Species of the temperate zone, due to the thermal effects of oceanic waters, are inhabited mainly in the southern and southeastern parts of the sea.
In coastal zones there are numerous settlements of mussels, littorinas and other mollusks, barnacles, sea urchins, and many crustaceans.
A rich invertebrate fauna has been discovered at the great depths of the Sea of Okhotsk. Glass sponges, sea cucumbers, deep-sea corals, and decapod crustaceans live here.
The Sea of Okhotsk is rich in fish. The most valuable salmon species are chum salmon, pink salmon, coho salmon, chinook salmon and sockeye salmon. Commercial fishing for herring, pollock, flounder, cod, navaga, capelin and smelt is carried out here.
The Sea of Okhotsk is home to large mammals - whales, seals, sea lions and fur seals. There are many seabirds that organize noisy “bazaars” on the coasts.
The UN recognized the enclave of the Sea of Okhotsk as part of the Russian shelf
Inessa Dotsenko
The UN Commission on the Limits of the Continental Shelf recognized the Sea of Okhotsk enclave with an area of 52 thousand square kilometers as part of the Russian continental shelf.
According to ITAR-TASS, this was stated by the Minister of Natural Resources and Environment of the Russian Federation Sergei Donskoy.
We have officially received a document from the UN Commission on the Continental Shelf on the satisfaction of our application to recognize the enclave in the Sea of Okhotsk as the Russian shelf. This has actually already taken place, so I would like to congratulate everyone on this,” he said.
The commission's decision, according to the minister, is unconditional and has no retroactive effect. Now the enclave is fully subject to Russian jurisdiction.
As ITAR-TASS reports, Donskoy also said that Russia’s application to expand the continental shelf in the Arctic will be ready this fall. The time for submitting the application to the UN Commission on the Limits of the Continental Shelf depends on how other countries’ claims to the enclave in the Arctic will be built.
All resources that will be discovered there will be extracted exclusively within the framework of Russian legislation,” Donskoy noted. He said that according to geologists, the total volume of hydrocarbons discovered in this area exceeds a billion tons.
Magadan Governor Vladimir Pecheny believes that recognition of the enclave in the middle of the Sea of Okhotsk as part of the Russian continental shelf opens up new prospects for the economy of Kolyma and the entire Far East. First of all, it will relieve the region’s fishermen of numerous administrative barriers.
Firstly, fishing for fish, crab, and shellfish can be carried out freely anywhere in the Sea of Okhotsk. No special permits from the border service will be required either when going to sea or upon returning. Secondly, when Russian territory is not only the 200-mile zone, but the entire sea, we will get rid of poaching by foreign fishermen in our waters. It will be easier to preserve the unique environment,” the press service of the regional government quotes Pecheny as saying.
Reference
In the center of the Sea of Okhotsk there is an elongated enclave of considerable size. Previously, all of it was considered the “open sea”. Vessels of any state could move and fish freely on its territory. In November 2013, Russia managed to prove rights to 52 thousand square kilometers of water in the center of the Sea of Okhotsk. For comparison, this is larger than the area of Holland, Switzerland or Belgium. The center of the Sea of Okhotsk ceased to be part of the World Ocean and became completely Russian. After approval at the UN session, the process of legally classifying the enclave as part of the Russian continental shelf can be considered completely completed.
In winter, the temperature of the surface waters of the sea usually does not fall below the freezing point (at salinity values of 31-33.5‰ this is -1.6- -1.8°C). In summer, the temperature of surface waters usually does not exceed 7-14°C. Its values in different areas of the sea, both in summer and winter, are determined both by the depth of the place and by horizontal and vertical movements of water. In coastal shallow areas of the sea and in areas of warm currents, the water temperature is higher than in areas of strong tidal mixing, where relatively warm surface and cold subsurface waters mix, or along the coast of Sakhalin, where the cold East Sakhalin Current passes.
The southern part of the sea is under the influence of warm currents, and the surface water temperature along the Kuril Islands is higher than along the continent. However, in February-March, the influx of warm waters by the Soya Current weakens (the La Perouse Strait is clogged with ice transported from the north), and the temperature of the warm waters of the East Kamchatka Current invading the sea drops to 1°-2°C. But even so, the temperature of the surface waters of the southeastern part of the sea is several degrees higher than the temperature of the waters of the rest of the sea by 1-2°C.
Spring warming (from April-May) of surface waters everywhere leads to an increase in temperature values and the disappearance of ice. The most warmed areas are the shelf areas and the southern part of the sea (up to 2 and 6°C, respectively).
The restructuring of the temperature field to the summer state is most noticeable in June. Areas of strong tidal mixing (for example, the entrance to Shelikhov Bay) remain the least heated.
The highest values (on average about 14°C) of sea surface water temperatures were recorded in August. The water temperature is higher in areas of warm currents (for example, off the coast of Hokkaido) and off the coast (except for the coast of Sakhalin Island, where upwelling is observed) and lower in areas of tidal mixing. Due to the influence of warm and cold currents, the water temperature in the western (cold) and eastern (relatively warm) parts of the sea usually differs by several degrees.
Cooling of the surface waters of the sea begins in September. In October, the most noticeable decrease in temperature to 4°C in the northwestern part of the sea is due to the rise of deep waters. However, in most of the sea the temperature is still quite high (5.5 to 7.5 ° C). In November, there is a sharp decrease in surface water temperature. North of 54°N. the water temperature drops below 2°C.
The surface water temperature distribution in December remains the same with minor changes until spring. The lowest water temperature values correspond to areas of polynyas, and the highest values correspond to areas of influx of warm waters (the La Perouse Strait and the southeastern part of the sea) and rising waters (Kashevarov Bank).
The distribution of water temperature on the surface allows us to identify thermal fronts (Fig.).
Main thermal fronts of the Sea of Okhotsk
Fronts form during ice-free periods and are most developed in late summer.
The thermal fronts of the sea have a different origin: tidal mixing, at the boundaries of warm currents, river runoff (especially from the Amur Estuary) and zones of subsurface water rise. Fronts arise at the boundary of warm currents near the western coast of Kamchatka (a warm current from the Pacific Ocean) and along Hokkaido (a warm current from the Sea of Japan). Fronts also form at the boundaries of strong tide zones (Shelikhov Bay and the area of the Shantar Islands). The East Sakhalin coastal front is caused by the rise of cold subsurface waters during the southern winds of the summer monsoon. The front in the central part of the sea corresponds to the average line of the distribution of packed ice in winter. Throughout the summer, there is a zone of cold (less than 3°C) water in the area of the Kashevarov Bank.
In the western part of the deep-sea basin, an anticyclonic eddy is observed throughout the year. The reason for its existence is the invading jets of warm water of the Soya Current and the denser cold waters of the East Sakhalin Current. In winter, due to the weakening of the Soya current, the anticyclonic vortex weakens.
Distribution of water temperature at a horizon of 50 m
At a horizon of 50 m, the water temperature is usually close (in winter) or lower (in summer) to the surface temperature. In winter, the horizontal distribution of water temperature in areas of ice formation is similar to the surface distribution due to intense mixing of water up to a horizon of 50 m (and on the shelf to a depth of 100 m). Only in May, in most areas of the sea, except for zones of strong tidal mixing, the surface layer warms up and, thus, a cold subsurface layer appears deeper than it. In July, at a horizon of 50 m, water with a temperature of less than 0°C is observed only in the northwestern part of the sea. In September, water temperatures continue to rise. But, if in Shelikhov Bay it is about 3°C, near the Kuril Islands 4°C, then in most of the sea it is about 0°C.
Maximum water temperatures at a horizon of 50 m are usually observed in October. But already in November, the area of water with a temperature of less than 1°C increases sharply.
Features of the water temperature field are:
Two tongues of relatively warm (more than 0°C) waters along the Kamchatka Peninsula and from the 4th Kuril Strait to Jonah Island;
Warm water zone in the southwestern part of the sea. In winter it narrows to a narrow strip along the island. Hokkaido, and in summer it occupies most of the deep-sea basin.
Distribution of water temperature at a horizon of 100 m
At the 100 m horizon, water of the cold subsurface layer is usually noted. Therefore, the lowest water temperature values are typical for the coastal areas of the northwestern part of the sea, and the highest for the zone along the Kuril Islands and for the strip from the 4th Kuril Strait to the Kashevarov Bank.
Intra-annual changes in water temperature are similar to those noted for the 50 m horizon.
Distribution of water temperature at a horizon of 200 m
The peculiarity of this horizon is a sharp decrease in seasonal changes. But they (winter decrease and summer increase in water temperature) always exist. The cold subsurface layer on this and underlying horizons can be identified only in areas of intense tidal mixing (in particular, in the Kuril Straits and the adjoining part of the sea). The distribution of warm water, as well as at higher horizons, can be traced in two branches - along Kamchatka and from the 4th Kuril Strait to Iona Island.
Distribution of water temperature at a horizon of 500 m
At the horizon of 500 m and deeper, there are no seasonal changes. At this horizon the average annual temperature is higher than at the sea surface. Deeper than this horizon, the water temperature continuously decreases.
Distribution of water temperature at a horizon of 1000 m
The maximum water temperature at a horizon of 1000 m is located near the Krusenstern Strait (2.44°C), through which, apparently, the greatest transfer of warm water to the Sea of Okhotsk occurs at this depth. The lowest water temperatures on this horizon (2.2°С) are observed not in the northern part of the sea, but in the southern part.
Water temperature fields at standard horizons are given below.
The Sea of Okhotsk is part of the Pacific Ocean, separated from it by the Kamchatka Peninsula, the Kuril Islands and the island of Hokkaido. The sea washes the shores of Russia and Japan.
Area - 1603 thousand km². Average depth - 1780 m, maximum depth - 3916 m.
Ideas about the cyclonic nature of the general circulation of the sea developed in the late 19th - early 20th centuries. mainly based on indirect data (Fig. 2.9). Due to the lack of direct measurements of currents, calculations on mathematical models by the dynamic method remain the main research method, for example (K.V. Moroshkin 1966).
The results of current measurements in the Sea of Okhotsk confirm the presence of cyclonic circulation (Rogachev K.A. 2001). Currents were measured for 3 months at Kashevarova on the horizon 140 m at a distance of 14 m from the bottom. (Fig. 2.9 v. 1.) The currents are unidirectional (as in the Middle Caspian) from north to south (Fig. 2.10 a). The figure shows that the currents change with a high frequency, and the constant component is also large (45-120 cm/s).
It should be noted that there are 4 different opinions regarding the nature of the currents observed on the Kashevarov Bank.
The author himself (Rogachev 2001) believes that high-frequency currents are tidal currents. Low frequency currents o are formed as a result of the interaction of two tidal harmonics with close periods of 25.82 hours. and 23.93h. Modulations are formed with periods of 13.66 days (I - II, II - III, III - IV, etc., Fig. 2.10 a, b).
V.N. Zyryanov (1985) believes that the Kashevarov bank is an example of a topographic vortex system. The controlling mechanism of water dynamics in the bank area is a vortex torus formed by the anticyclonic Taylor-Hogg vortex and its cyclonic satellite.
Rice. 2.9. Scheme of large-scale currents in the Sea of Okhotsk. Sea currents, represented as streamlines, are indicated by a smooth thick line with arrows. 1-4 – buoy placement points. (Bondarenko A.L., Rudykh N.I. 2003). The dotted line is the estimated large-scale circulation contour, coinciding with the isobath line.
A.L. Bondarenko (Bondarenko et al. 2004) uses a filter to identify the moving equilibrium average with an averaging period of 48 hours. Large-scale currents U (indicated in the figure by a thick line) and currents of the tidal waves themselves V (Fig. 2.10b). A comparison of Figures 2.10a and 2.10b shows that at moments I, II, III, etc., the amplitudes of velocity fluctuations of the wave currents themselves are minimal; at moments I ′, II ′, III ′, etc. – maximum.
The wave transfer of U changes with the same period of 13.66 days, and is proportional to the values amplitudes of fluctuations in the speed of tidal wave currents V approximately according to equation
U=3V
The maximum velocities of tidal wave currents V are 35 cm/s, and the maximum velocities of large-scale circulation currents U are 120 cm/s. (Bondarenko and others 2004) concludes: tidal waves V, as well as continental shelf waves, are capable of creating wave transport at high speeds.
In the work (Shchevyev 2005) he doubts the possibility of waves with an amplitude of up to 35 cm/s, oscillations around the equilibrium position, creating unidirectional transfer of water masses with maximum speeds of up to 120 cm/s. Another interpretation of this unique experiment is being considered.
Rice. 2.10. Currents in the Sea of Okhotsk on the Kashevarov Bank (Rogachev K. A. 2001).
In addition to the measurement results (Fig. 2.10), a spectral analysis of high-frequency oscillations, which appeared to be tidal, was performed. He showed that these are inertial oscillations with a period (13.63 - 15.38 hours) and two harmonics (Fig. 2.11).
Rice. 2.11. Spectral density function of currents on the Kashevarov bank. (Built by Trubkin I.P., GOIN).
It is more plausible to explain the observational results (Fig. 2.10.) as follows: in all internal and marginal seas of the northern hemisphere there are long-term wave currents running around the basin cyclonically.
On fig. 2.10a shows the result of measuring the total flow, n.ch. and v.ch. The resulting movement of these currents is the large-scale cyclonic circulation. Movement long period wave flow is deflected into the Coriolis force field. Inertial waves are formed (Fig. 2.10.b).
