Average and maximum salinity of the Pacific Ocean. World oceans. What we learned

The Pacific Ocean is the largest and oldest on our planet. It is so huge that it can easily accommodate all the continents and islands combined and that is why it is often called the Great. The area of ​​the Pacific Ocean is 178.6 million square meters. km, which corresponds to 1/3 of the surface of the entire globe.

general characteristics

The Pacific Ocean is the most important part of the World Ocean, as it contains 53% of its total water volume. It extends from east to west for 19 thousand kilometers, and from north to south - 16 thousand. Moreover, most of its waters are located in southern latitudes, and a smaller part - in northern latitudes.

The Pacific Ocean is not only the largest, but also the deepest body of water. The maximum depth of the Pacific Ocean is 10994 m - this is exactly the depth of the famous Mariana Trench. The average figures fluctuate within 4 thousand meters.

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The Pacific Ocean owes its name to the Portuguese navigator Ferdinand Magellan. During his long journey, calm and calm weather reigned across the oceanic expanses, without a single storm or storm.

The bottom topography is very diverse.
Here you can find:

• basins (Southern, Northeastern, Eastern, Central);
• deep-sea trenches (Mariana, Philippine, Peruvian;
• elevations (East Pacific Rise).

The properties of water are formed through interaction with the atmosphere and are largely subject to change. The salinity of the Pacific Ocean is 30-36.5%.
It depends on the location of the waters:

• maximum salinity (35.5-36.5%) is characteristic of waters in tropical zones, where relatively little precipitation is combined with intense evaporation;
• salinity decreases to the east under the influence of cold currents;
• salinity also decreases under the influence of heavy precipitation, this is especially noticeable at the equator.

Geographical position

The Pacific Ocean is conventionally divided into two regions - southern and northern, the border between which lies along the equator. Since the ocean is colossal in size, its boundaries are the coasts of several continents and partially bordering oceans.

In the northern part, the border between the Pacific and Arctic Oceans is the line connecting Cape Dezhnev and Cape Prince of Wales.

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In the east, the Pacific Ocean borders the coasts of South and North America. A little further south, the boundary between the Pacific and Atlantic Oceans extends from Cape Horn to Antarctica.

In the west, the waters of the Pacific Ocean wash Australia and Eurasia, then the border runs along the Bass Strait on the eastern side, and descends along the meridian south to Antarctica.

Climate Features

The climate of the Pacific Ocean is subject to general latitudinal zonality and the powerful seasonal influence of the Asian continent. Due to its huge area, the ocean is characterized by almost all climatic zones.

• Northeast trade winds reign in the tropical and subtropical zones of the northern hemisphere.
• The equatorial zone is characterized by calm weather throughout the year.
• In the tropics and subtropics of the southern hemisphere, the southeast trade wind dominates. In the summer, tropical hurricanes of incredible strength - typhoons - arise in the tropics.

The average air temperature in the equatorial and tropical zones is 25 Celsius. On the surface, the water temperature fluctuates between 25-30 C, while in the polar regions it drops to 0 C.

Near the equator, precipitation reaches 2000 mm, decreasing to 50 mm per year near the coast of South America.

Seas and islands

The Pacific coastline is most indented in the west, and least in the east. In the north, the Strait of Georgia cuts deeply into the mainland. The largest Pacific bays are California, Panama and Alaska.

The total area of ​​the seas, bays and straits belonging to the Pacific Ocean occupies 18% of the total ocean area. Most of the seas are located along the coasts of Eurasia (Okhotsk, Bering, Japanese, Yellow, Philippine, East China), along the Australian coast (Solomonovo, New Guinea, Tasmanovo, Fiji, Coral). The coldest seas are located near Antarctica: Ross, Amundsen, Somov, D'Urville, Bellingshausen.

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All rivers of the Pacific Ocean basin are relatively short, but with rapid water flow. The largest river flowing into the ocean is the Amur.

There are about 25 thousand large and small islands in the Pacific Ocean, with unique flora and fauna. For the most part, they are located in equatorial, tropical and subtropical natural complexes.

The large archipelagos of the Pacific Ocean include the Hawaiian Islands, the Philippine archipelago, Indonesia, and the largest island is New Guinea.

An urgent problem in the Pacific Ocean is the significant pollution of its waters. Industrial waste, oil spills, and thoughtless destruction of ocean inhabitants can cause irreparable harm to the Pacific Ocean, upsetting the fragile balance of its ecosystem.

What have we learned?

When studying the topic “Pacific Ocean”, we became acquainted with a brief description of the ocean and its geographical location. We found out which islands, seas and rivers belong to the Pacific Ocean, what are the characteristics of its climate, and became familiar with the main environmental problems.

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Magellan discovered the Pacific Ocean in the fall of 1520 and named the ocean the Pacific Ocean, “because,” as one of the participants reports, during the passage from Tierra del Fuego to the Philippine Islands, more than three months, “we never experienced the slightest storm.” In terms of the number (about 10 thousand) and total area of ​​islands (about 3.6 million km²), the Pacific Ocean ranks first among the oceans. In the northern part - Aleutian; in the western - Kuril, Sakhalin, Japanese, Philippine, Greater and Lesser Sunda, New Guinea, New Zealand, Tasmania; in the central and southern regions there are numerous small islands. The bottom topography is varied. In the east - the East Pacific Rise, in the central part there are many basins (North-Eastern, North-Western, Central, Eastern, Southern, etc.), deep-sea trenches: in the north - Aleutian, Kuril-Kamchatka, Izu-Boninsky; in the west - Mariana (with the maximum depth of the World Ocean - 11,022 m), Philippine, etc.; in the east - Central American, Peruvian, etc.

The main surface currents: in the northern part of the Pacific Ocean - warm Kuroshio, North Pacific and Alaskan and cold Californian and Kuril; in the southern part - the warm South Trade Wind and East Australian Wind and the cold Western Wind and Peruvian Wind. The water temperature on the surface at the equator is from 26 to 29 °C, in the polar regions up to −0.5 °C. Salinity 30-36.5 ‰. The Pacific Ocean accounts for about half of the world's fish catch (pollock, herring, salmon, cod, sea bass, etc.). Extraction of crabs, shrimps, oysters.

Important sea and air communications between the countries of the Pacific basin and transit routes between the countries of the Atlantic and Indian Oceans lie across the Pacific Ocean. Major ports: Vladivostok, Nakhodka (Russia), Shanghai (China), Singapore (Singapore), Sydney (Australia), Vancouver (Canada), Los Angeles, Long Beach (USA), Huasco (Chile). The International Date Line runs across the Pacific Ocean along the 180th meridian.

Plant life (except bacteria and lower fungi) is concentrated in the upper 200th layer, in the so-called euphotic zone. Animals and bacteria inhabit the entire water column and the ocean floor. Life develops most abundantly in the shelf zone and especially near the coast at shallow depths, where the temperate zones of the ocean contain a diverse flora of brown algae and a rich fauna of mollusks, worms, crustaceans, echinoderms and other organisms. In tropical latitudes, the shallow water zone is characterized by widespread and strong development of coral reefs, and mangroves near the shore. As we move from cold zones to tropical zones, the number of species increases sharply, and the density of their distribution decreases. About 50 species of coastal algae - macrophytes are known in the Bering Strait, over 200 near the Japanese Islands, over 800 in the waters of the Malay Archipelago. In the Soviet Far Eastern seas there are about 4000 known species of animals, and in the waters of the Malay Archipelago - at least 40-50 thousand . In the cold and temperate zones of the ocean, with a relatively small number of plant and animal species, due to the mass development of some species, the total biomass increases greatly; in the tropical zones, individual forms do not receive such a sharp predominance, although the number of species is very large.

As we move away from the coasts towards the central parts of the ocean and with increasing depth, life becomes less diverse and less abundant. In general, the fauna of T. o. includes about 100 thousand species, but only 4-5% of them are found deeper than 2000 m. At depths of more than 5000 m, about 800 species of animals are known, more than 6000 m - about 500, deeper than 7000 m - slightly more than 200, and deeper than 10 thousand m - only about 20 species.

Among coastal algae - macrophytes - in temperate zones, fucus and kelp are especially notable for their abundance. In tropical latitudes they are replaced by brown algae - sargassum, green algae - caulerpa and halimeda and a number of red algae. The surface zone of the pelagic zone is characterized by the massive development of unicellular algae (phytoplankton), mainly diatoms, peridinians and coccolithophores. In zooplankton, the most important are various crustaceans and their larvae, mainly copepods (at least 1000 species) and euphausids; there is a significant admixture of radiolarians (several hundred species), coelenterates (siphonophores, jellyfish, ctenophores), eggs and larvae of fish and benthic invertebrates. In T. o. It is possible to distinguish, in addition to the littoral and sublittoral zones, a transition zone (up to 500-1000 m), bathyal, abyssal and ultra-abyssal, or a zone of deep-sea trenches (from 6-7 to 11 thousand m).

Planktonic and bottom animals provide abundant food for fish and marine mammals (nekton). The fish fauna is exceptionally rich, including at least 2000 species in tropical latitudes and about 800 in the Soviet Far Eastern seas, where there are, in addition, 35 species of marine mammals. The most commercially important fish are: anchovies, Far Eastern salmon, herring, mackerel, sardine, saury, sea bass, tuna, flounder, cod and pollock; among mammals - sperm whale, several species of minke whales, fur seal, sea otter, walrus, sea lion; from invertebrates - crabs (including Kamchatka crab), shrimp, oysters, scallops, cephalopods and much more; from plants - kelp (sea kale), agarone-anfeltia, sea grass zoster and phyllospadix. Many representatives of the fauna of the Pacific Ocean are endemic (the pelagic cephalopod nautilus, most Pacific salmon, saury, greenling fish, northern fur seal, sea lion, sea otter, and many others).

The large extent of the Pacific Ocean from North to South determines the diversity of its climates - from equatorial to subarctic in the North and Antarctic in the South. Most of the ocean surface, approximately between 40° north latitude and 42° south latitude, is located in the equatorial, tropical and subtropical climate zones. Atmospheric circulation over the Pacific Ocean is determined by the main areas of atmospheric pressure: the Aleutian low, the North Pacific, the South Pacific and the Antarctic highs. These centers of atmospheric action in their interaction determine the great constancy of northeastern winds in the North and southeastern winds of moderate strength in the South - trade winds - in the tropical and subtropical parts of the Pacific Ocean and strong westerly winds in temperate latitudes. Particularly strong winds are observed in the southern temperate latitudes, where the frequency of storms is 25-35%, in the northern temperate latitudes in winter - 30%, in summer - 5%. In the West of the tropical zone, tropical hurricanes - typhoons - are frequent from June to November. The northwestern part of the Pacific Ocean is characterized by monsoon atmospheric circulation. The average air temperature in February decreases from 26-27 °C at the equator to –20 °C in the Bering Strait and –10 °C off the coast of Antarctica. In August, the average temperature varies from 26-28 °C at the equator to 6-8 °C in the Bering Strait and to –25 °C off the coast of Antarctica. Throughout the entire Pacific Ocean, located north of 40° south latitude, there are significant differences in air temperature between the eastern and western parts of the ocean, caused by the corresponding dominance of warm or cold currents and the nature of the winds. In tropical and subtropical latitudes, the air temperature in the East is 4-8 °C lower than in the West. In the northern temperate latitudes, the opposite is true: in the East the temperature is 8-12 °C higher than in the West. The average annual cloudiness in areas of low atmospheric pressure is 60-90%. high pressure - 10-30%. The average annual precipitation at the equator is more than 3000 mm, in temperate latitudes - 1000 mm in the West. and 2000-3000 mm in the East. The least amount of precipitation (100-200 mm) falls on the eastern outskirts of subtropical areas of high atmospheric pressure; in the western parts the amount of precipitation increases to 1500-2000 mm. Fogs are typical for temperate latitudes, they are especially frequent in the Kuril Islands area.

Under the influence of atmospheric circulation developing over the Pacific Ocean, surface currents form anticyclonic gyres in subtropical and tropical latitudes and cyclonic gyres in northern temperate and southern high latitudes. In the northern part of the ocean, the circulation is formed by warm currents: the North Trade Wind - Kuroshio and the North Pacific and cold California Current. In the northern temperate latitudes, the cold Kuril Current dominates in the West, and the warm Alaskan Current dominates in the East. In the southern part of the ocean, the anticyclonic circulation is formed by warm currents: the South Trade Wind, East Australian, zonal South Pacific and cold Peruvian. North of the equator, between 2-4° and 8-12° northern latitude, northern and southern circulations are separated throughout the year by the Intertrade Wind (Equatorial) Countercurrent.

The average temperature of the surface waters of the Pacific Ocean (19.37 °C) is 2 °C higher than the temperature of the waters of the Atlantic and Indian oceans, which is the result of the relatively large size of that part of the Pacific Ocean area that is located in well-warmed latitudes (over 20 kcal/cm2 per year ), and limited communication with the Arctic Ocean. The average water temperature in February varies from 26-28 °C at the equator to -0.5, -1 °C north of 58° north latitude, near the Kuril Islands and south of 67° south latitude. In August, the temperature is 25-29 °C at the equator, 5-8 °C in the Bering Strait and -0.5, -1 °C south of 60-62° south latitude. Between 40° south latitude and 40° north latitude, the temperature in the eastern part of the Pacific Ocean is 3-5 °C lower than in the western part. North of 40° north latitude, the opposite is true: in the East the temperature is 4-7 °C higher than in the West. South of 40° south latitude, where zonal transport of surface water predominates, there is no difference between water temperatures in the East and West. In the Pacific Ocean there is more precipitation than evaporating water. Taking into account river flow, over 30 thousand km3 of fresh water enters here annually. Therefore, the salinity of surface waters is T. o. lower than in other oceans (average salinity is 34.58‰). The lowest salinity (30.0-31.0‰ and less) is observed in the West and East of the northern temperate latitudes and in the coastal areas of the eastern part of the ocean, the highest (35.5‰ and 36.5‰) - in the northern and southern subtropical latitudes, respectively. latitudes At the equator, water salinity decreases from 34.5‰ or less, in high latitudes - to 32.0‰ or less in the North, to 33.5‰ or less in the South.

The density of water on the surface of the Pacific Ocean increases quite uniformly from the equator to high latitudes in accordance with the general distribution of temperature and salinity: at the equator 1.0215-1.0225 g/cm3, in the North - 1.0265 g/cm3 or more, in the South - 1.0275 g/cm3 and more. The color of the water in subtropical and tropical latitudes is blue, transparency in some places is more than 50 m. In the northern temperate latitudes, the color of the water is dark blue, along the coast it is greenish, transparency is 15-25 m. In Antarctic latitudes, the color of the water is greenish, transparency is up to 25 m .

Tides in the northern part of the Pacific Ocean are dominated by irregular semidiurnal (height up to 5.4 m in the Gulf of Alaska) and semidiurnal (up to 12.9 m in Penzhinskaya Bay of the Sea of ​​Okhotsk). The Solomon Islands and part of the coast of New Guinea have daily tides of up to 2.5 m. The strongest wind waves are observed between 40 and 60° south latitude, in latitudes where westerly storm winds dominate (the “roaring forties”), in the Northern Hemisphere - to the north 40° north latitude. The maximum height of wind waves in the Pacific Ocean is 15 m or more, length over 300 m. Tsunami waves are typical, especially often observed in the northern, southwestern and southeastern parts of the Pacific Ocean.

Ice in the northern part of the Pacific Ocean forms in seas with harsh winter climatic conditions (Bering, Okhotsk, Japanese, Yellow) and in bays off the coast of Hokkaido, the Kamchatka and Alaska peninsulas. In winter and spring, ice is carried by the Kuril Current to the extreme northwestern part of the Pacific Ocean. Small icebergs are found in the Gulf of Alaska. In the South Pacific, ice and icebergs form off the coast of Antarctica and are carried into the open ocean by currents and winds. The northern border of floating ice in winter runs at 61-64° south latitude, in summer it shifts to 70° south latitude, icebergs at the end of summer are carried to 46-48° south latitude. Icebergs are formed mainly in the Ross Sea.

The distribution of salinity in the oceans depends mainly on climatic conditions, although salinity is partly influenced by some other factors, especially the nature and direction of currents. Outside the direct influence of land, the salinity of surface waters in the oceans ranges from 32 to 37.9 ppm.
The distribution of salinity over the ocean surface, outside the direct influence of runoff from land, is determined primarily by the influx and outflow balance of fresh water. If the inflow of fresh water (precipitation + condensation) is greater than its outflow (evaporation), i.e., the inflow-outflow balance of fresh water is positive, the salinity of surface waters will be lower than normal (35 ppm). If the inflow of fresh water is less than the outflow, i.e. the inflow-outflow balance is negative, the salinity will be above 35 ppm.
A decrease in salinity is observed near the equator, in the calm zone. The salinity here is 34-35 ppm, since here a large amount of precipitation exceeds evaporation.
To the north and south of here, salinity first increases. The area of ​​greatest salinity is in the trade wind belts (approximately between 20 and 30° north and south latitudes). We see on the map that these stripes are especially clearly defined in the Pacific Ocean. In the Atlantic Ocean, salinity is generally greater than in other oceans, and the maximums are located just near the tropics of Cancer and Capricorn. In the Indian Ocean the maximum is around 35°S. w.
To the north and south of its maximum, salinity decreases, and in the middle latitudes of the temperate zone it is below normal; it is even smaller in the Arctic Ocean. We see the same decrease in salinity in the southern circumpolar basin; there it reaches 32 ppm and even lower.
This uneven distribution of salinity depends on the distribution of barometric pressure, winds and precipitation. In the equatorial zone, the winds are not strong, evaporation is not great (although it is hot, the sky is covered with clouds); the air is humid, contains a lot of vapor, and there is a lot of precipitation. Due to relatively small evaporation and dilution of salt water by precipitation, salinity becomes slightly lower than normal. North and south of the equator, up to 30° N. w. and Yu. sh., is an area of ​​high barometric pressure, the air is drawn towards the equator: trade winds blow (constant north-eastern and south-eastern winds).
Downward currents of air, characteristic of areas of high pressure, descending to the surface of the ocean, heat up and move away from the saturation state; cloud cover is low, precipitation is low, and fresh winds promote evaporation. Due to large evaporation, the inflow-outflow balance of fresh water is negative, salinity is higher than normal.
Further to the north and south, fairly strong winds blow, mainly from the southwest and northwest. The humidity here is much higher, the sky is covered with clouds, there is a lot of precipitation, the incoming and outgoing balance of fresh water is positive, and the salinity is less than 35 ppm. In the polar regions, the melting of transported ice also increases the supply of fresh water.
The decrease in salinity in the polar countries is explained by the low temperature in these areas, insignificant evaporation, and high cloudiness. In addition, the northern polar seas are adjacent to vast expanses of land with large deep rivers; a large influx of fresh water greatly reduces salinity.
We have indicated the general features of the distribution of salinity in the oceans, and in some places there are deviations from the general rule due to currents. Warm currents coming from low latitudes increase salinity; cold currents, on the contrary, decrease it. The Gulf Stream especially has this effect on the salinity of the northeastern Atlantic Ocean. We see that in that part of the Barents Sea where the branches of the warm Gulf Stream enter, salinity increases.
The influence of cold currents is felt, for example, off the coast of South America, where the Peruvian Current reduces salinity. The Benguela Current also affects the decrease in salinity off the western coast of Africa. When two currents meet near Newfoundland, the warm Gulf Stream and the cold Labrador Current (desalinated by the ice mountains), the salinity changes over a very short distance. This can be seen even by the color of the water: ribbons of two colors are visible - blue (warm current) and green (cold current). Sometimes large rivers desalinate coastal parts of the ocean, such as the Congo and Niger in the Atlantic Ocean. The influence of the Amazon is felt at a distance of 300 nautical miles from the mouth, and the Yenisei and Ob at an even greater distance.
Let us point out another feature in the distribution of salinity, which has remained a mystery for a long time, and for this purpose we will consider the highest salinity of the oceans.
The highest salinities of the oceans:

In the South Atlantic Ocean......37.9 ppm
In the North Atlantic Ocean......37.6 ppm
In the Indian Ocean...................36.4 ppm
In the North Pacific.........35.9 ppm,
In the South Pacific.........36.9 ppm

As you can see, the highest salinity is in the Atlantic Ocean; The Pacific Ocean is smaller, but it would seem that it should be the other way around, since the largest rivers flow into the Atlantic Ocean, and its basin is more than two times larger than the Pacific Ocean. Only small coastal rivers (Columbia and Colorado) flow into the Pacific Ocean in America; Only in Asia is the Pacific Ocean watershed moved further inland and such significant rivers as the Amur, Yellow River, and Yangtze Jiang flow into it.
Prof. Voeikov gave the following explanation for this phenomenon. Vapors from the Pacific Ocean do not spread far inland, but are concentrated by the marginal mountains and, in most of their mass, return back in the form of rivers to the ocean. Sediments from the Atlantic Ocean are carried far inland, especially in Asia, where they extend to the Stanovoy Range. The river flow is less, only about 25% of precipitation flows back into the ocean. In addition, many drainless regions adjoin the borders of the Atlantic basin: the Sahara, the Volga basin, Central Asia, where large rivers (Syr Darya, Amu Darya) carry water to the drainage basin of the Aral Sea. Apparently, most of the water from these drainless areas does not return to the ocean. All this increases the salinity of the Atlantic Ocean compared to others. Thus, this issue should be resolved by calculating the incoming and outgoing balance of fresh water.
Let's move on to consider the salinity of the accessory seas. They; show significantly greater differences in this regard. If the seas are connected by convenient and deep straits to the ocean, then their salinity differs little from the salinity in the latter; but if there are underwater rapids that do not allow ocean waters to freely penetrate into the sea, then the salinity of the sea can be different from the salinity of the ocean. So, for example, in the marginal seas on; In eastern Asia, the salinity differs little from that of the ocean, and the differences depend on latitude and ice.
In the Bering and Okhotsk Seas, with cold currents, salinity.............. 30-32 ppm
In the Sea of ​​Japan, which has a warm current from the ocean............................34-35 ppm
In the Australian-Asian Sea, salinity is higher in the northern part and lower in the southern part. This is explained by the fact that it lies under the equator and there is a lot of rainfall here thanks to the mountainous islands, which condense the vapors.
The North Sea is open on the ocean side, and its salinity differs little from the salinity of the latter. The situation is different in the seas separated from the ocean by underwater rapids.
The Baltic, Black, Mediterranean and Red Seas have completely different salinities.
If a sea basin receives little precipitation, few rivers flow into it, evaporation is high, then salinity is high. We see this in the Mediterranean Sea, where the salinity is 37 ppm, and in the east it even reaches 39 ppm. In the Red Sea, the salinity is 39 ppm, and in its northern part it is even 41 ppm. In the Persian Gulf the salinity is 38 ppm. These three seas have high salinity, since the inflow-outflow balance of fresh water in each of them is sharply negative.
The Black Sea has low salinity, on the surface only 18 ppm. The basin of this sea is relatively small. Large rivers flow into it and desalinate it greatly.
The excess inflow of fresh water over flow is created mainly due to runoff from land.
As you can see, there are two seas lying next to each other, with completely different salinities. There is a continuous exchange of water between them. The more desalinated waters of the Black Sea penetrate into the Mediterranean Sea with a surface current, and the salty and heavy waters of the latter flow into the Black Sea with a deep current.
The same exchange occurs between the Atlantic Ocean and the Mediterranean Sea. Here the surface water flows from the Atlantic Ocean, and the deep current flows from the Mediterranean Sea to the ocean.
The Baltic Sea has low salinity. The Kattegat Straits, and especially the Sound and both Belts, are very shallow. In the North Sea, salinity is 32-34 ppm, in the Skagerrak it is 16 ppm, off the coast of Schleswig it is 16 ppm, and east of the Sound line - the island of Rügen, in the western part of the Baltic Sea, it is only 7-8 ppm, in the Gulf of Bothnia it is 3-5 ppm, in the Gulf of Finland, the salinity is 5 ppm, reaching only a third of the length of the bay, in the middle it is 4.5 ppm, and in the eastern part, where the Neva pours a lot of fresh water, it is only 1-2 ppm.
There are also two currents between the Baltic and North seas: a surface one from the Baltic to the North and a deep, saltier current from the North to the Baltic.
With depth, salinity in oceans and seas changes in different ways.
In the oceans, salinity changes little with depth, and in inland seas - depending on the physical and geographical conditions of the sea.
On the surface of the ocean, water evaporates, the solution concentrates, and the upper layer of water should sink down, but since the temperature at an insignificant depth is already low and cold water has a high density, the surface salty waters sink to a very insignificant depth, starting from where the salinity changes little with further deepening.
In inland seas, saltier water can in most cases sink from the surface to the bottom, so that salinity increases in this direction. However, this distribution of salinity is not an absolute rule. Thus, in the Black Sea we find a rapid increase in salinity to depths of 60-100 m, then the salinity slowly increases to 400 m, where it reaches a value of 22.5 ppm and, starting from here, remains almost constant until the very bottom. The increase in salinity at depth is explained by the penetration of heavy and salty Mediterranean waters into the Black Sea.
In different places of the world's oceans, surface density varies between 1.0276-1.0220. The highest density is observed in polar regions, the lowest in tropical regions, so the geographic distribution of sea water density on the surface depends on the distribution of water temperature, not salinity.

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1. Seas of the Arctic Ocean.

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3. Seas of the Atlantic Ocean

4. Caspian Sea-lake.

Seas of the Arctic Ocean

The seas of the Arctic Ocean include: the Barents Sea, the White Sea, the Kara Sea, the Laptev Sea, the East Siberian Sea and the Chukchi Sea.

All these seas wash the territory of Russia from the north. All seas, except the White Sea, are marginal, and the White Sea is internal. The seas are separated from each other by archipelagos of islands - natural boundaries, and where there is no clear boundary between the seas, it is drawn conditionally. All seas are shelf seas and therefore shallow, only the northern waters of the Laptev Sea extend to the edge of the Nansen Basin (depth 3385 m). Thus, the Laptev Sea is the deepest of the northern seas. The second deepest of the northern seas is the Barents Sea, and the shallowest is the East Siberian Sea, the average depth of all seas is 185 m.

The seas are open, and there is a free exchange of water between them and the ocean. From the Atlantic, warm and salty waters flow into the Barents Sea in two powerful streams: the Spitsbergen and North Cape currents. In the east, the Arctic Ocean basin is connected to the Pacific Ocean by the narrow Bering Strait (its width is 86 km, depth 42 m), so water exchange with the Pacific Ocean is noticeably difficult.

The seas of the Arctic Ocean are characterized by large runoff from the mainland; about 70% of the runoff of the Russian territory belongs to the basin of this ocean. The influx of river water reduces the salinity of the seas to 32‰. Near the mouths of large rivers, salinity drops to 5‰, and only in the north-west of the Barents Sea does it approach 35‰.

The climate of the seas is harsh, which is primarily due to their geographical location in high latitudes. All seas, except the White Sea, lie in the Arctic. This fact causes them to become very cold in winter, during the polar night. In the eastern part, the Arctic pressure maximum is formed, which maintains frosty, partly cloudy weather in winter. The Icelandic and Aleutian lows have a certain influence on the climate of the northern seas. The western regions of the Arctic in winter are characterized by cyclonic activity, which is especially pronounced in the Barents Sea: frosts soften, the weather is cloudy, windy, with snowfalls, and fog is possible. An anticyclone dominates over the central and eastern seas, so average January temperatures change as follows (in the direction from west to east): over the Barents Sea in January temperatures are -5o -15oC, and in the Laptev Sea and East Siberian Sea the average January temperature is about -30oC . Over the Chukchi Sea it is a little warmer - about -25°C, this is influenced by the Aleutian minimum. In the area of ​​the North Pole in January the temperature is about -40°C. Summer is characterized by continuous solar radiation during the long polar day.

Cyclonic activity weakens somewhat in summer, but air temperatures remain quite low, because... The bulk of solar radiation is spent on melting ice. Average July temperatures vary from 0°C on the northern edge of the seas to +5°C on the coast of the continent, and only over the White Sea in summer the temperature reaches +10°C.

In winter, all seas, with the exception of the western edge of the Barents Sea, freeze. Most of the ocean is covered with ice all year round; this ice remains for several years and is called pack ice. Ice is in constant motion. Despite its considerable thickness (up to 3 m or more), the ice is subject to fractures, and cracks and even polynyas form between the ice floes. The surface of the pack ice is relatively flat, but in some places hummocks up to 5-10 m high can appear. In addition to ice, icebergs that have broken off from the cover glaciers that are present on the Arctic islands can be found in the seas. In summer, the ice area decreases, but even in August, drifting ice floes can be seen in the seas off the coast. The ice regime changes annually; now, with climate warming, there is an improvement in ice conditions (for sea vessels). The water temperature remains low all year round: in summer +1o +5o (in the White Sea up to +10o), in winter -1-2oC (and only in the western part of the Barents Sea about +4oC).

The bioproductivity of the northern seas is low, the flora and fauna of these seas are relatively poor, and the depletion of flora and fauna occurs in the direction from west to east, due to the severity of the climate. Thus, the ichthyofauna of the Barents Sea includes 114 species of fish, and 37 species live in the Laptev Sea. The Barents Sea is inhabited by: cod, haddock, halibut, sea bass, herring, etc. The eastern seas are dominated by salmon (nelma, pink salmon, chum salmon, salmon), whitefish (omul, vendace) and smelt.

Pacific Seas

The seas of the Pacific Ocean include: the Bering Sea, the Sea of ​​Okhotsk, and the Sea of ​​Japan. They wash the eastern shores of Russia. The seas are separated from the Pacific Ocean by ridges of islands: the Aleutian, Kuril and Japanese, behind which there are deep-sea trenches (the maximum depth at the Kuril-Kamchatka trench is 9717 m). The seas are located in the subduction zone of two lithospheric plates: the Eurasian and the Pacific. The seas are also located in the zone of transition of the continental crust to the oceanic crust; the shelf is small, so the seas of the Pacific Ocean are significantly deep. The deepest (4150 m) and largest in size is the Bering Sea. On average, the depth of all three seas is 1350 m, which is much deeper than the seas of the Arctic Ocean. The seas stretch for almost 5,000 km from north to south, while they have free water exchange with the Pacific Ocean. A distinctive feature of these seas is the relatively small influx of river water into them. Less than 20% of the water flow from the territory of Russia belongs to the Pacific Ocean basin.

The climate of the seas is largely determined by the monsoon circulation, which smoothes out the climatic differences of the seas, especially in winter. The average air temperature in January varies from -15-20°C near the coast and to -5°C near the island arcs. The harshest winter is in the Sea of ​​Okhotsk (500 km from Oymyakon). In summer, the climatic differences between the seas are more noticeable. In the Bering Sea, the average temperature in summer is +7 +10° C, and in the Sea of ​​Japan the temperature reaches +20° C. In the summer season, typhoons often sweep over the Sea of ​​Japan. In winter, ice forms in the seas: the Sea of ​​Okhotsk freezes completely, and the Bering and Japanese Seas freeze only near the coasts. In winter, the water temperature ranges from +2оС to -2оС, and in summer the water temperature varies from +5оС in the north to +17оС in the south. Water salinity varies from 30‰ in the Sea of ​​Okhotsk to 33‰ in the Bering and Sea of ​​Japan.

The seas of the Pacific Ocean are characterized by tidal currents; in Penzhinskaya Bay the highest tidal waves are observed off the coast of Russia - up to 13 m; near the Kuril Islands the height of tidal waves is up to 5 m.

The organic world of the seas is quite rich; plankton and seaweed grow abundantly in shallow waters. The ichthyofauna is represented by arctic and boreal fish species, and in the Sea of ​​Japan also by subtropical fish species. In total, about 800 species of fish live in the seas of the Far East, of which more than 600 are in the Sea of ​​Japan. Of commercial importance are salmon (chum salmon, pink salmon, coho salmon, chinook salmon, etc.), willow herring, and Pacific herring, and bottom fish include flounder, halibut, cod, as well as pollock and sea bass; in more southern parts - mackerel, conger eels, tuna and sharks. In addition, the Pacific seas are rich in crabs and sea urchins; fur seals and sea otters live on the islands.

Seas of the Atlantic Ocean

Seas of the Atlantic Ocean: Baltic Sea, Black Sea, Azov Sea.

These seas are inland, they wash small areas of the country. The connection between these seas and the ocean is rather weak, and therefore their hydrological regime is unique.

The Baltic Sea (Varyazhskoe) is the westernmost of the seas of Russia. It is connected to the ocean through the shallow Denmark Strait and the shallow North Sea. The Baltic Sea itself is also shallow; it was formed in the Quaternary and was covered with continental ice to the bottom. The sea is shallow, the maximum depth of the Baltic Sea is 470 m (south of Stockholm), in the Gulf of Finland the depth does not exceed 50 m.

The climate of the Baltic Sea is formed under the influence of the western transfer of air masses from the Atlantic. Cyclones often pass through the sea; annual precipitation exceeds 800 mm. Temperatures in summer over the Baltic are + 16-18°C, water temperature + 15-17°C. In winter, thaws dominate the sea; the average temperature in January is around 0°C, but with the invasion of Arctic air masses, the temperature can drop to -30°C. Only the Gulf of Finland freezes in winter, but in some severe winters the entire sea can freeze.

About 250 rivers flow into the Baltic Sea, but 20% of the river flow is brought by the Neva River. The salinity of water in the Baltic Sea does not exceed 14‰ (the average oceanic 35‰), off the coast of Russia (in the Gulf of Finland) the salinity is 2-3‰.

The Baltic fauna is not rich. Of commercial importance are: sprat, herring, eel, smelt, cod, whitefish, and lamprey. In addition, the sea is home to seals, whose numbers have recently been declining due to pollution of sea waters.

The Black Sea is the warmest of the Russian seas. It is almost equal in area to the Baltic Sea, but greatly exceeds it - due to its great depth - in volume: the maximum depth of the Black Sea is 2210 m. The Black Sea is connected to the Atlantic through a system of inland seas and straits.

The climate of the Black Sea is close to the Mediterranean (warm, wet winters and relatively dry, hot summers). In winter, northeast winds dominate over the sea. When cyclones pass, stormy winds often occur; The average air temperature in winter ranges from 0°C off the coast of Russia to +5°C on the southern coast of the sea. In summer, northwest winds prevail, the average air temperature is +22-25°C. Many rivers flow into the sea, the Danube giving the largest flow. The salinity of the Black Sea waters is 18-22‰, but near the mouths of large rivers the salinity decreases to 5-10‰.

Life lives only in the upper layers of the sea, because... Below 180 m, poisonous hydrogen sulfide is dissolved in water. The Black Sea is home to 166 species of fish: Mediterranean species - mackerel, horse mackerel, sprat, anchovy, tuna, mullet, etc.; freshwater species - pike perch, bream, ram. Pontic relics have been preserved here: beluga, stellate sturgeon, sturgeon, herring. Dolphins and seals live in the Black Sea among mammals.

The Sea of ​​Azov is the smallest sea in Russia and the shallowest in the world: its average depth is 7 m, and its greatest depth is 13 m. This sea is a shelf sea, it is connected to the Black Sea by the Kerch Strait. Due to its small size and deeply inland position, the sea has the features of a continental climate rather than a marine one. The average air temperature in January is about -3°C, but with stormy winds from the north-east, the temperature can drop to -25°C, although very rarely. In summer, the air over the Sea of ​​Azov warms up to +25°C.

Two large rivers flow into the Sea of ​​Azov: Don and Kuban, which bring over 90% of the annual river flow. In addition to these rivers, about 20 other small rivers flow into it. Water salinity is about 13‰; By August, the water in the sea warms up to +25°C, and near the coast up to +30°C. In winter, most of the sea freezes; ice formation begins in December, in the Taganrog Bay. The sea is freed from ice only in April.

The organic world of the Azov Sea is diverse: it is home to about 80 species of fish, mainly Mediterranean and freshwater species - sprat, anchovy, pike perch, bream, sturgeon, etc.

Caspian sea-lake

The Caspian Sea belongs to the internal closed basin; it is a relict lake, but in the Neogene it was connected with the World Ocean. The Caspian Lake is the largest lake on Earth; in terms of its hydrological regime and large size, it is very similar to the sea.

The Caspian basin consists of three parts: northern – shelf, with depths up to 50 m; medium – with depths of 200-800 m; the southern one is deep-sea, with a maximum depth of 1025 m. The length of the Caspian Sea from north to south is 1200 km, from west to east – about 300 km.

The climate of the Caspian Sea varies from temperate in the north to subtropical in the south. In winter, the sea is under the influence of the Asian High, and north-easterly winds blow over it. The average air temperature ranges from -8°C in the north to +10°C in the south. The shallow northern part is covered with ice from January to March.

In summer, clear, hot weather prevails over the Caspian Sea, the average summer air temperature is +25-28°C. The annual precipitation over the Northern Caspian Sea is about 300 mm, and in the southwest it falls up to 1500 mm.

More than 130 rivers flow into the sea, but 80% of the river flow comes from the Volga River. Water salinity ranges from 0.5‰ in the north to 13‰ in the southeast.

The organic world of the Caspian Sea is not rich, but endemic; it is home to herring, gobies, sturgeon (beluga, stellate sturgeon, sterlet, sturgeon), carp, bream, pike perch, roach and other fish species, as well as seal.