The lowest salinity of the water. ocean water salinity
Includes all the seas and oceans of the Earth. It occupies about 70% of the planet's surface, it contains 96% of all water on the planet. The world ocean consists of four oceans: Pacific, Atlantic, Indian and Arctic.
The size of the Pacific oceans - 179 million km2, Atlantic - 91.6 million km2 Indian - 76.2 million km2, Arctic - 14.75 million km2
The boundaries between the oceans, as well as the boundaries of the seas within the oceans, are drawn rather conventionally. They are determined by land areas that delimit the water space, internal currents, differences in temperature and salinity.
The seas are divided into internal and marginal. The inland seas protrude deep enough into the land (for example,), and the marginal seas adjoin the land at one edge (for example, the North, Japan).
Pacific Ocean
The Pacific is the largest of the oceans. It is located in both the northern and southern hemispheres. In the east, its border is the coast of the North and, in the west - the coast and, in the south - Antarctica. He owns 20 seas and more than 10,000 islands.
Because the Pacific Ocean captures almost everything but the coldest,
it has a varied climate. over the ocean fluctuates from +30°
Water temperature in Atlantic Ocean ranges from -1 °С to + 26 °С, the average water temperature is +16 °С.
The average salinity of the Atlantic Ocean is 35%.
The organic world of the Atlantic Ocean is rich in green plants and plankton.
Indian Ocean
Most of indian ocean located in warm latitudes, humid monsoons dominate here, which determine the climate of East Asian countries. The southern edge of the Indian Ocean is very cold.
The currents of the Indian Ocean change direction depending on the direction of the monsoons. The most significant currents are the Monsoon, Tradewind and.
The Indian Ocean is diverse, there are several ridges, between which relatively deep basins are located. The deepest point of the Indian Ocean is the Java Trench, 7 km 709 m.
The water temperature in the Indian Ocean ranges from -1°C off the coast of Antarctica to +30°C, the average water temperature is +18°C.
The average salinity of the Indian Ocean is 35%.
Arctic Ocean
Most of the Arctic Ocean is covered with a layer of ice - in winter it is almost 90% of the ocean's surface. Only near the coast ice freezes to land, while most of the ice drifts. Drifting ice is called "pack".
The ocean is completely located in the northern latitudes, it has a cold climate.
A number of large currents are observed in the Arctic Ocean: a transarctic current passes along the north of Russia, as a result of interaction with the warmer waters of the Atlantic Ocean, a current is born.
The relief of the Arctic Ocean is characterized by a developed shelf, especially off the coast of Eurasia.
Water under ice always has a negative temperature: -1.5 - -1°C. In summer, the water in the seas of the Arctic Ocean reaches +5 - +7 °С. The salinity of the ocean water is significantly reduced in summer due to the melting of ice and, this applies to the Eurasian part of the ocean, full-flowing Siberian rivers. So in winter the salinity in different parts 31-34% o, in summer off the coast of Siberia it can be up to 20% o.
Maritime transport is an essential element of international trade. Countries such as, and others, cut off from the mainland and not having enough of their own resources, are entirely dependent on. A potential environmental hazard is associated with this: the wreck of a ship carrying oil, fuel oil, coal and others causes serious damage.
The main feature that distinguishes water oceans from the waters of the land, is their high salinity. The number of grams of substances dissolved in 1 liter of water is called salinity.
Sea water is a solution 44 chemical elements, but salts play a primary role in it. Table salt gives water a salty taste, while magnesium salt gives it a bitter taste. Salinity is expressed in ppm (%o). This is a thousandth of a number. In a liter of ocean water, an average of 35 grams of various substances are dissolved, which means that the salinity will be 35% o.
The amount of salts dissolved in will be approximately 49.2 10 tons. In order to visualize how large this mass is, we can make the following comparison. If all sea salt in dry form is distributed over the surface of the entire land, then it will be covered with a layer 150 m thick.
The salinity of the ocean waters is not the same everywhere. Salinity is influenced by the following processes:
- evaporation of water. In this process, salts with water do not evaporate;
- ice formation;
- fallout, lowering salinity;
- . The salinity of the ocean waters near the continents is much less than in the center of the ocean, since the waters desalinate it;
- melting ice.
Processes such as evaporation and ice formation contribute to an increase in salinity, while precipitation, river runoff, and melting ice lower it. main role salinity is affected by evaporation and precipitation. Therefore, the salinity of the surface layers of the ocean, as well as temperature, depends on latitude-related.
Over 96% water shell Planet Earth is occupied by the World Ocean, filled with water masses containing a significant amount of salt. The share of freshwater rivers and lakes is less than 4%.
The salinity of the world's oceans is a value showing the average number of grams of salt per kilogram of ocean water. This is one of the most important parameters affecting the underwater world. The average value of the indicator is 35 ‰, that is, a kilogram of ocean water contains 35 grams of salt.
properties of ocean water
The liquid in the ocean has a bitter-salty taste. It differs from fresh color, degree of transparency, specific gravity, freezing point, amount of minerals. It interacts differently with certain substances.
Advantages:
- has medicinal properties: antiseptic, healing, helping to strengthen the immune system;
- nourishes and strengthens the skin, hair, nails;
- beneficial effect on nervous system, has a calming effect due to a variety of minerals necessary for the normal functioning of the central nervous system.
Flaws:
- not intended for domestic use, including for watering soil and plants;
- cannot be used as a drink;
- swimming in salt water with some diseases and skin lesions can be harmful to health;
- not suitable for all living organisms.
What is water salinity
Salinity refers to the presence of dissolved substances in water that have the appropriate properties. Salts are substances whose molecules consist of acid base anions (nitrates, sulfates) combined with metal cations (potassium, sodium). Cations are positively charged, anions are negatively charged.
The reasons
According to the most common hypothesis, the seas and oceans were enriched with salt due to its leaching from the soil and rocks. The oceans and seas are filled with liquid mainly due to the rivers flowing into them.
In the process of flowing along the channel, streams fresh water come into contact with various rocks, from which salts and other substances are washed out, and are sent to the oceans. When heated from the sun's rays, the liquid evaporates, then again enters the rivers, and the process begins anew. Salt molecules cannot leave their location, since they do not participate in the evaporation process. Over the course of many millions of years, mineral compounds accumulated, and water bodies became more and more salty.
There is another hypothesis: the seas and oceans were not fresh from the beginning. During the formation of the planet Earth, due to powerful volcanic activity, acid rain fell on the surface, which filled the very first body of water. Gradually the acid molecules corroded rocks and formed with them new chemical compounds- salts, which gradually completely replaced acids.
How to measure
Since the 1970s, scientists have most commonly used the electrical method to measure salinity. Conductivity cells are lowered into the investigated liquid, their work is recorded by laboratory salt meters. Based on such a study, a measurement accuracy of up to 0.001 PSU is obtained. In addition to laboratory methods, simpler methods are used.
Instruments used to measure solutions:
- manual refractometer;
- hydrometer;
- conductometer.
With the help of these instruments, salinity can be studied independently. The refractometer is considered the most accurate instrument.
Salinity of the world's oceans
Measured in ppm (‰) - this is physical unit, denoting the number of grams of a certain substance in a kilogram of water. Depending on the latitude, the number of inflowing fresh rivers, climatic conditions and other factors, the indicators may vary.
Quiet
It occupies the territory of both hemispheres. In the west it is surrounded by the continents of Eurasia and Australia, in the east it borders on North and South America, in the south - with Antarctica. It occupies more than 30% of the Earth's surface, its area is 178,784,000 km². The volume is 710.36 million km³, which is almost half of the total volume of the World Ocean. The bottom relief is very diverse - here is the largest part of the deep-sea trenches of the World Ocean.
The average salinity is 34.5‰. Maximum rates are observed in tropical regions (up to 35.6 ‰) due to active evaporation of the liquid and poor precipitation. In the east, the figures are declining due to cold currents. At the equator, the parameters are also low due to heavy rainfall.
Indian
Most of the Indian Ocean is in the southern hemisphere. It borders Eurasia in the north and northeast, Africa in the west, and part of the Southern Ocean in the southeast. Square - 76,174,000 km². Volume - 282.65 km³.
Average salinity - 34.8‰. It is here, in the Red Sea and the Persian Gulf, that the highest rates of the entire world ocean are observed - 40–41‰. Values above 36 ‰ correspond to the degree of salinity of the water masses of the southern tropical belt and the Arabian Sea in the northern hemisphere. Low rates (30–34 ‰) are observed in the Bay of Bengal due to desalination from the Irrawaddy, Ganges and Brahmaputra rivers.
In the arctic and equatorial regions, one can notice a fairly significant seasonal difference in salinity. The monsoon current in winter transports water masses of low salinity from the northeastern oceanic regions and forms a "tongue" of low salinity along 5 ° north latitude, which disappears in summer.
Atlantic
It is in second place in terms of size. Area - 106,500,000 km². Volume - 330.1 km³. In the west it borders on North and South America, in the east - on Europe and Africa, in the south - on Antarctica.
The degree of salt content in the Atlantic Ocean is almost the same as in the Pacific - an average of 35.4 ‰. The indicators are lowered in zones located near the equator due to heavy rainfall (34 ‰) and increased in the subtropics and tropics (<37.25‰). The maximum value is observed in the Mediterranean Sea - 39 ‰. A sharp decrease in indicators is recorded in areas near the mouths of the rivers (La Plata - 18–19 ‰).
Arctic
The smallest ocean in the world is located entirely in the northern hemisphere, bordering Eurasia and North America. Square - 14,750,000 km². Volume - 18.07 km³.
This is the ocean with the lowest salt content - 32 ‰. The indicator varies depending on the layer of water bodies. Near the surface, lower values are observed due to the desalination effect of rivers, meltwater runoff and very little evaporation.
The next layer is more salty (up to 34.3 ‰ ) due to the merging of the upper with lower (37 ‰ and above), underlying intermediate, the source of which is in the Greenland Sea. The deep layer is characterized by lower values (35 ‰) compared to the previous one; it is also transferred from the Greenland Sea.
Southern
It is a collection of the southern parts of the oceans washing Antarctica (Pacific, Atlantic, Indian). There are no clear outlines of its boundaries. Area - about 86,000,000 km² (data vary).
The depth also matters - the lower the water layer is located, the higher the concentration of salts in it, and the surface layer is the freshest among others. All parameter changes are in the range from 33 ‰ to 35 ‰. The formation and melting of glaciers is one of the factors in changing salinity.
Why does salinity change?
The level of salinity of water masses is not constant, the indicators change, they are not the same even in the same climatic zone in different seasons.
Reasons for change:
- evaporation intensity;
- the amount of precipitation;
- formation/melting of ice cover;
- the volume and number of inflowing rivers;
- underwater currents.
The distribution of water salinity depends on depth. Evaporating, water molecules (H 2 O) leave the ocean, but the salt does not evaporate and remains in the remaining amount of liquid. As a result, salinity rises. When precipitation falls in the ocean, the amount of water increases, but the content of mineral compounds remains the same. As a result, salinity decreases.
In coastal areas, where many fresh rivers flow into the ocean, salinity is lower. For example, in the Caspian Sea in the Volga delta, the indicator is 0.3 ‰ , while in the open part the values are 12–13 ‰.
Water is involved in the formation of ice, but not salt. Therefore, glaciers contain precisely freshwater reserves. When ice forms, salt molecules remain in the unfrozen liquid and thereby increase its salinity. During the melting period, on the contrary, the indicator decreases due to an increase in the amount of water.
Salinity varies depending on the currents - warm ones increase it, cold ones lower it. In addition, depth affects the performance: the lower it is, the fresher the water.
Research
In the 18th century, Mikhail Vasilyevich Lomonosov studied oceanic waters. Later, in the 19th century, the available data were enriched by research Ivan Fedorovich Kruzenshtern and Yuri Fedorovich Lisyansky, who participated in the oceanographic expedition.
More detailed studies were carried out by E. X. Lenz(1804-1865). With the help of a barometer invented by him, the scientist studied deep water samples. He refuted the previously prevailing assertion that salinity is higher in areas near the equator compared to other areas. Lenz proved that in these areas the water density and salt concentration are lower than in areas with a subtropical climate. The research methods and tools invented by this scientist are still used today.
Since 1881, another Russian researcher has taken up oceanography S. O. Makarov. He was engaged in the study of the oceans and, in particular, issues related to the Black Sea water masses. Makarov revealed the mechanism of the opposite (surface and deep) currents of the Bosporus, using a number of original techniques for this. The data obtained shed light on many features of the hydrological regime and paleogeography of the Black Sea. To In addition, the scientist compiled a map of the currents of the Pacific Ocean.
In the 19th and 20th centuries, research was continued by Yuli Mikhailovich Shokalsky. Thanks to his scientific work, the scientist was able to finally single out oceanography as a separate science.
Water temperature
The temperature in the vast majority of the oceans is constant and ranges from 0 to +2 ° C (ocean water does not freeze at 0 ° C, but at -2 ° C due to the high salt content). But at a depth of more than 2 km from the surface, this parameter can change.
Factors affecting temperature change:
- heating from the sun;
- the state of the atmosphere that affects the conservation of heat;
- flowing rivers;
- currents;
- wind.
The temperature of the water rises as you get closer to the equator.
Difference from fresh water
The freezing point of salt water is on average 2 degrees Celsius lower than fresh water. Its density is also higher, 1 liter of sea liquid is 25 grams heavier than fresh water. Thanks to this, it is easier to stay afloat in it, as if the water pushes the body up. In the ocean, the water masses are richer in composition, they contain up to 60 chemical compounds.
Sea water takes longer to evaporate than fresh water. Liquid molecules must first separate from the salt environment. After that, the water can go into a gaseous state. The separation process takes a certain amount of time.
The conditions for the existence of the inhabitants of rivers and seas are different, have their own characteristics. Not all ocean organisms will be able to survive in freshwater rivers and lakes.
People should not drink salty sea liquid in large quantities, as the water-salt balance and osmotic pressure may be disturbed in the body ( excess hydrostatic The Dead Sea is the saltiest on Earth. Here the indicators reach 270 ‰. The reservoir is located near the territories of Israel and Jordan. The density of the liquid is 1.3-1.4 g / m³, which reduces the possibility of drowning to almost zero. Fresh water is considered to be water, the salinity of which is less than 1‰. The least salty sea (7‰) is the Baltic. Salt water can only freeze if it is near the surface or slightly below the surface with a more saline layer. In the northern seas, fish do not freeze due to special proteins contained in the blood, which prevent the water from turning into ice. The water of the Caspian Sea is also salty, but its composition is very different from the sea, but you can’t drink it either. The set of useful minerals in it is also not so large. The reservoir is closed and not too deep, so it can be attributed to lakes. Fishing is well developed here and seafood is harvested on an industrial scale. Visiting the salt lakes of Russia, you can see the "cosmic" landscapes of the shores of such reservoirs, there is practically no vegetation on them. With the help of this water, diseases of the skin and respiratory tract are treated. Most of the reservoirs are located on the border with Kazakhstan, in very dry places. The most famous salt lakes in Russia:
Video
Watch a video that explains why the sea water is salty.
Salinity of the waters of the oceans.
The main feature that distinguishes the waters of the oceans from the waters of land is their high salinity. The number of grams of substances dissolved in 1 liter of water is called salinity.
Sea water is a solution of 44 chemical elements, but salts play a primary role in it. Table salt gives water a salty taste, while magnesium salt gives it a bitter taste. Salinity is expressed in ppm (%o). This is a thousandth of a number. In a liter of ocean water, an average of 35 grams of various substances are dissolved, which means that the salinity will be 35% o.
The amount of salts dissolved in the World Ocean will be approximately 49.2 10 tons. In order to visualize how large this mass is, we can make the following comparison. If all sea salt in dry form is distributed over the surface of the entire land, then it will be covered with a layer 150 m thick.
The salinity of the ocean waters is not the same everywhere. Salinity is influenced by the following processes:
evaporation of water. In this process, salts with water do not evaporate;
ice formation;
precipitation that lowers salinity;
runoff of river waters. The salinity of the ocean waters near the continents is much less than in the center of the ocean, since the waters of the rivers desalinate it;
melting ice.
Processes such as evaporation and ice formation contribute to an increase in salinity, while precipitation, river runoff, and melting ice lower it. The main role in changing salinity is played by evaporation and precipitation. Therefore, the salinity of the surface layers of the ocean, as well as temperature, depends on climatic conditions associated with latitude.
The salinity of the Red Sea is 42%. This is explained by the fact that not a single river flows into this sea, there is very little precipitation here (tropics), and the evaporation of water from strong heating by the sun is very large. The water evaporates from the sea, but the salt remains. The salinity of the Baltic Sea is not higher than 1%o. This is due to the fact that this sea is located in a climatic zone where evaporation is less, but more precipitation falls. However, the overall picture can be disturbed by currents. This is especially noticeable on the example of the Gulf Stream - one of the most powerful currents in the ocean, whose branches, penetrating far into the Arctic Ocean (salinity 10-11% o), carry water with a salinity of up to 35% 0. The reverse phenomenon is observed off the coast of North America, where, under the influence of a cold Arctic current, such as the Labrador Current, the salinity of water off the coast decreases.
The salinity of the deep part of the ocean as a whole is practically constant. Here, separate layers of water with different salinity can alternate in depth depending on their density.
Waters, the salinity of which does not exceed 1%o, are called fresh.
The temperature of the waters of the oceans .
The ocean receives a lot of heat from the sun. Occupying a large area, it receives more heat than land.
But the sun's rays only heat the top layer of water, only a few meters thick. Down from this layer, heat is transferred as a result of constant mixing of water. But it should be noted that the water temperature decreases with depth, first abruptly, and then smoothly. At depth, the water is almost uniform in temperature, since the depths of the oceans are mainly filled with waters of the same origin, which form in the polar regions of the Earth. At a depth of more than 3-4 thousand meters, the temperature usually ranges from +2°C to 0°C.
The temperature of surface waters is also not the same and is distributed depending on the geographical latitude. The farther from the equator, the lower the temperature. This is due to the different amount of heat that comes from the Sun. Due to the sphericity of our planet, the angle of incidence of the sun's ray at the equator is greater than at the poles, therefore, the equatorial latitudes receive more heat than the polar ones. At the equator, the highest temperatures of the ocean waters are observed - + 28-29 ° С. To the north and south of it, the water temperature drops. Due to the proximity of cold Antarctica, the rate of temperature decrease to the south is somewhat faster than to the north.
The temperature of sea water is also affected by the climate of the surrounding areas. It is especially high in the seas surrounded by hot deserts, for example, in the Red Sea - up to 34 ° C, in the Persian Gulf - up to 35.6 ° C. In temperate latitudes, the temperature varies depending on the time of day.
In addition to the geographic latitude and climate of the surrounding territories, currents also affect the temperature of ocean waters. Warm currents carry warm waters from the equator to temperate latitudes, while cold currents carry cold water from the polar regions. Such a movement of water contributes to a more uniform distribution of temperatures in the water masses.
The highest average sea surface temperature in the Pacific Ocean is 19.4°C. The second place (17.3°C) is occupied by the Indian Ocean. In third place is the Atlantic Ocean, which has an average temperature of about 16.5 ° C. The lowest water temperature in the Arctic Ocean is on average just above 1°C. Consequently, for the entire World Ocean, the average surface water temperature is about 17.5°C.
So, the ocean absorbs heat by 25-50% more than the land, and this is its huge role for the living beings of the entire planet. The sun heats its water all summer, and in winter this heated water gradually gives off heat to the atmosphere. Thus, the World Ocean is something like the "central heating boiler" of the Earth. Without it, such severe frosts will come on Earth that all living things will die. It has been calculated that if the oceans did not keep their heat so carefully, then the average temperature on Earth would be -21 ° C, which is as much as 36 C lower than what we actually have.
Transparency of the waters of the oceans .
If you collect sea water in a jar, it will seem transparent. However, with an increase in the thickness of the water layer, it acquires a bluish or greenish tint. The change in color is due to the absorption and scattering of light. In addition, suspensions of various compositions affect the color of ocean waters.
The transparency of ocean water indirectly depends on the amount of suspended particles in it. In the field, transparency is determined with a Secchi disk. A flat disk, the diameter of which does not exceed 40 cm, is lowered into the water. The depth at which it becomes invisible is taken as an indicator of transparency in the area.
The transparency of the waters of the oceans decreases with distance from the equator. As the temperature of the water decreases, the amount of oxygen dissolved in it increases, which leads to an increase in the number of microorganisms that inhabit the ocean. However, in the polar seas, it increases again due to low temperatures, which hinder the development of life in the water. Therefore, the most transparent sea is the Wedell Sea in Antarctica. To measure transparency, a Secchi disk is used - this is a black and white disk lowered into the water, while the depth at which it disappears is fixed to determine transparency. In the Wedell Sea, it disappears at a depth of 79 m. The second most transparent is the Sargasso Sea - 66 m. Theoretically, in distilled water, the Secchi disk should disappear at a depth of 80 m.
Catch the bug (fix the bug).
The main part of the hydrosphere is land water, and the initial link in the world water cycle is water in the atmosphere. Glaciers make up a small part of the hydrosphere. The largest ocean in terms of area is the Atlantic Ocean, and the smallest ocean in terms of area is the Arctic Ocean. A bay is a part of an ocean or sea that flows deep into land. The narrow part of the ocean or sea between two land areas is called a strait. An island is a small piece of land surrounded on all sides by water, and parts of the continents or islands that fall deep into the ocean are called archipelagos. Water in the atmosphere is found only in the form of water vapour.
This strait separates the coasts of North America and Eurasia. (Berengov)
This bay washes the shores of Eurasia, is part of the Indian Ocean. (Bengal)
A channel connecting the waters of the Atlantic and Pacific oceans. (Panamanian)
A strait that can be seen from the top of the Atlas Mountains. (Gibraltar)
The strait separating the island of Madagascar and the mainland of Africa. (Mozambican)
The largest and deepest bay. (Guinean)
Sea of the Arctic Ocean, the Ob River flows into it. (Kara)
A strait named after a famous navigator. Separates part of the islands from the mainland of South America. (Magelanov)
The name of this bay is associated with the name of the state, which in turn is named after the Aztec god of war - Mehitli. (Mexican)
The bay has a point with the following coordinates: 60 0 NL 85 0 h.d. (Hudson)
The sea has a point with coordinates: 70 0 S 40 0 h.d. (Weddell)
A bay that separates the largest peninsula from the mainland of Eurasia. (Persian)
A bay washing the southern shores of the smallest continent. (Big Australian)
A channel connecting the waters of parts of the Atlantic and Indian oceans. (Suez)
Canal built in Europe. (Kiel)
The southernmost strait connecting the waters of the Indian and Pacific oceans. (bass)
The strait through which the prime meridian passes. It washes the southern tip of the island of Great Britain. (English Channel)
"Colored" sea washing the shores of China. (yellow)
The largest inland sea. (Mediterranean)
Sea without shores. (Sargasso)
Mainland | A vast area of the continental crust, surrounded on all sides by the waters of the oceans. |
Island | A small piece of land surrounded on all sides by water. |
Archipelago | A group of islands lying at a short distance from each other and having, as a rule, the same origin and similar geological structure. |
Sea | Part of the ocean adjacent to the mainland or protruding into it, separated from the ocean by land areas or underwater uplifts of the bottom. |
gulf | Part of a sea or ocean that extends deep into land. |
strait | A narrow body of water that separates land or connects adjacent seas or oceans. |
Channel | An artificially created watercourse used for navigation or the movement of water. |
World Ocean | The continuous water space of the Earth, surrounding the continents and islands. |
For a free moment.
Suez Canal
The construction of the Suez Canal is one of the most grandiose events of the 19th century. The idea of building a canal connecting the Mediterranean and Red Seas originated with the Arabs in the Middle Ages. Then this was actively discussed in France, first under Louis XIV, later under Napoleon. But work on the construction of the canal began only in the middle of the 19th century under the leadership of the French entrepreneur, engineer and diplomat Ferdinand Lesseps. He managed to obtain from the ruler of Egypt, Said Pasha, a concession for the construction and further operation of the canal for 99 years. The canal was expected to be built in 6 years, but it took 10 years. The grand opening of the canal took place on November 17, 1869.
In 1869, the canal passed sea vessels with a draft of only 8m, but then it was deepened and expanded more than once. At the beginningXXcentury, 4 thousand ships passed through the canal annually, and the volume of transported cargo was 20–30 million tons. But by the mid-1960s, the traffic turnover exceeded 20 thousand ships, and the volume of cargo - 250 million tons.
The Suez Canal connected Europe with Asian countries. Its construction shortened the routes between the largest seaports in Europe and Asia by an average of two times.
The main cargo transported through the canal was oil from the Persian Gulf region, transported to Europe.
In the 50s–70sXXcentury, the growth of traffic along the canal was interrupted twice. The first time was in 1956-1957 after the nationalization by Egypt of the Suez Canal Company, owned by France and Great Britain. The second time was in 1967–1975, when, after the Arab-Israeli war, the Suez Canal was closed to ship traffic for a long time. After its opening in 1975, the number of ships passing through the canal began to increase rapidly. The channel was reconstructed: expanded 1.5 times (up to a maximum width of 365m) and deepened to 21 m.
The waters of the White Sea are less desalinated due to freer communication with the ocean. In its basin, the salinity of surface waters is 24-26% o, in the Gorlo 28-30% o, and in the bays it is much lower and fluctuates strongly under the influence of surge and tidal level fluctuations. Sometimes in the Dvina, Kandalaksha and Onega bays, almost fresh water is replaced by water with a salinity of 20-25%o.[ ...]
The waters of the inland seas, located in tropical latitudes, where there is little precipitation, few rivers, and high evaporation, are more saline than oceanic waters. These are the Mediterranean, Red and Persian Gulf seas. The Mediterranean Sea, characterized by a negative freshwater balance and difficult water exchange with the ocean through the narrow Strait of Gibraltar, has a salinity of surface waters higher than that of the ocean. From the Strait of Gibraltar to about. Sicily it is 37-38%o, in the eastern part of the sea 39%0 and more.[ ...]
The salinity of the surface waters of the seas often differs significantly from the salinity of oceanic waters (sometimes it exceeds it, sometimes it turns out to be less). These differences are determined by the conditions of water exchange between the seas and the ocean, the influence of climate and land water runoff. The salinity of the surface waters of the seas, the water exchange of which occurs more or less freely, is close to oceanic. With difficult water exchange, the differences can be significant.[ ...]
The salinity of the Ocean is not a constant value. It depends on the climate (the ratio of precipitation and evaporation from the surface of the Ocean), the formation or melting of ice, sea currents, near the continents, on the influx of fresh river waters. In the open Ocean, salinity ranges from 32-38%; in the marginal and Mediterranean seas, its fluctuations are much greater. Experiencing fluctuations in the amount of dissolved salts, sea water is distinguished by the exceptional constancy of their ratio to each other. The ratio of dissolved substances is preserved in various parts of the Ocean, on its surface and in deep layers. Based on this regularity, a method has been built for determining the salinity of sea waters by the amount of any one element contained in them, most often chlorine.[ ...]
The ocean is the main acceptor and accumulator of solar energy, since water has a high heat capacity. The water shell (hydrosphere) includes: salty waters of the World Ocean and inland seas; fresh waters of the land, concentrated in mountain ice, rivers, lakes, swamps. Consider the ecological characteristics of the aquatic environment.[ ...]
The ocean belongs to the group of saline waters, while sea waters are sometimes brines (for example, the Red Sea) or semi-solid (for example, the Sea of \u200b\u200bAzov), that is, they have a sharply different concentration, less or more than the average, little changing in composition ocean water. The transition is sometimes quite abrupt.[ ...]
In the ocean, the difference in temperature and salinity is small, but the described process enhances the vertical mixing of water.[ ...]
The volume of water on the globe is measured at 1386 million km3, which means that each of us has 350 million m3 of water, which is equal to ten reservoirs such as Mozhayskoye on the river. Moscow. Unfortunately, there is every reason for this. After all, a person needs not just any water, but only fresh water, that is, containing no more than 1 g of salts per 1 liter, and at the same time it must be of high quality. It is known that 97.5% of the water is concentrated in the World Ocean, the salinity of which is 35%a, or 35 g/l. Fresh water accounts for only 2.5%, while more than 2/3 of it is conserved in glaciers and snowfields, and only 0.32% falls on lakes and rivers. The most important and used for a variety of needs, river waters account for only 0.0002% of the total water reserves [Lvovich, 1974].[ ...]
In the Pacific Ocean, to the north of the subpolar front, the North Pacific intermediate water is formed with a salinity of 33.6 to 34.6% o, which then spreads to the south at depths of 500-1500 m.[ ...]
In all oceans and seas, there is a constant ratio of salts that make up the water. The total mass of salts in sea water is 48-1015 tons, or about 3.5% of the total mass of ocean water. This amount of salts would be enough to form a salt layer up to 45 m thick over the entire surface of our planet. For every 1000 g of ocean water, there are 35 g of salts, i.e. the salinity of the oceans averages 35%.[ ...]
The world ocean is heterogeneous both in salinity and in temperature. It is possible to distinguish isometric regions, layers and the thinnest layers in it. The highest water temperature in the ocean (404°C) was recorded at a hot spring 480 km off the west coast of America. Water heated to such a temperature did not turn into steam, since the source was located at a considerable depth under conditions of high pressure. The cleanest water in the world is found in the Weddell Sea in Antarctica. Its transparency corresponds to the transparency of distilled water. At the same time, the waters of the World Ocean are in constant motion, their temperature and currents affect the state of air masses and determine the weather and climatic conditions in the surrounding areas.[ ...]
The area of salt waters (seas, oceans) is just over 70% of the Earth's surface. Fresh waters (less than 1 g/l of salt) make up slightly less than 6% of the reserves, or, in absolute terms, 90 million km3. But the whole trouble is that only about 3% of fresh water is easily accessible reserves such as rivers, lakes and reservoirs, the rest is glaciers, groundwater. Thus, we can only use about 2.5 million km3 of water. But part of this water is polluted and unfit for consumption.[ ...]
The average salinity of the waters on the surface of various oceans is not the same: the Atlantic 35.4% o, the Pacific 34.9 ° / oo, the Indian 34.8% o. 10 shows the average salinity on the surface of the oceans in the southern and northern hemispheres.[ ...]
The World Ocean is the water shell of the Earth, with the exception of water bodies on land and the glaciers of Antarctica, Greenland, polar archipelagos and mountain peaks. The oceans are divided into four main parts - Pacific, Atlantic, Indian, Arctic oceans. The waters of the World Ocean, going into the land, form seas and bays. The seas are relatively isolated parts of the ocean (for example, the Black, Baltic, etc.), and the bays do not protrude into the land as much as the seas, and in terms of the properties of the waters differ little from the World Ocean. In the seas, the salinity of water can be higher than oceanic (35%), as, for example, in the Red Sea, up to 40%, or lower, as in the Baltic Sea, from 3 to 20%.[ ...]
Usually in water there are various impurities of organic and inorganic origin. Distinguish between salt and fresh water. The main mass of water on our planet is salt water, which forms the salty World Ocean and most of the mineralized underground waters of deep occurrence (1.5 ... 2 km).[ ...]
Fronts in the ocean arise due to the influence of a variety of mechanisms. Sometimes they look very distinct in the fields of temperature and salinity, while in the density field they are almost not expressed. Sharp changes in the properties at the fronts turn out to be significant due to the fact that they affect the dynamics. A review of satellite observations over temperature fronts is made in . The main climatic frontal zones (where fronts are most often recorded) in the northern part of the Pacific Ocean are shown in fig. 13.11; they were discussed in Rodin's work. One of the important types of fronts is associated with the Ekman convergence in the surface layer. Examples of such fronts are subtropical fronts, which are observed at latitudes from 30 ° N. sh. up to 40°S sh. Their changes associated with fluctuations in the Ekman divergence were studied in . The second type of fronts is formed at the boundary of water masses (see). Such a front separates, for example, the waters of the subarctic and subtropical gyres. In the northern part of the Pacific Ocean (Fig. 13.11), this front is located at a latitude of 42 ° N. sh. It was formed at the meeting place of the cold, equator-directed, Oyashio current with the warm current of the polar direction - Kuroshio. On the surface, this front is well expressed in the sections of temperature and salinity, but in the density field it is hardly noticeable.[ ...]
In the World Ocean, physical, chemical, biological and other processes continuously occur that change the salinity, i.e., reduce or increase the concentration of the solution. However, regardless of the absolute concentration of the solution, the quantitative ratios between the main ions remain constant. Therefore, it is sufficient to know the concentration of one of the components in order to determine the rest. To determine salinity, the sum of ions Cl + Br + I, called chlorine content, is used, the concentration of which in sea water is the highest.[ ...]
The bulk of the water is concentrated in the oceans. Its average depth is more than 4000 m, it covers an area equal to 361 million km2 (71% of the earth's surface), and is characterized by high salinity (3.5%). Continental water bodies cover about 5% of the Earth's area. Of these, surface waters (lakes, rivers, swamps, etc.) account for a very small part (0.2%), glaciers - 1.7%. Groundwater makes up about 4% of the total volume of the hydrosphere. The entire planetary water supply reaches 1450 million km.[ ...]
Sea water contains 89% chlorides, 10% sulfates and 0.2% carbonates, while fresh water contains 80% carbonates, 13% sulfates and 7% chlorides. The water of closed seas, such as the Caspian, is not typically marine. It is significantly less salty and contains three times more carbonates than the water of the oceans. According to modern concepts, the salinity of the water of the seas and oceans is "primary", which did not change during geological periods.[ ...]
Processes that change oceanological characteristics are continuously taking place in the World Ocean. As a result of uneven changes in these characteristics, their horizontal and vertical gradients arise, simultaneously with which processes develop, aimed at equalizing the properties of water masses, at the destruction of gradients. These are processes of vertical and horizontal exchange, i.e. mixing. Changes in temperature, salinity, and density with depth are associated with vertical gradients of these values. The gradient of each of these values can be positive or negative. If the density gradient is positive (the density increases with depth), the water masses are in a stable state; if it is negative, they are unstable: light waters tend to rise, and heavy ones tend to sink. An increase in density under the influence of a decrease in temperature or an increase in salinity on the surface causes the upper layers of water to sink and the lower ones to rise. As a result, the density of water in the upper, mixed layer decreases, while in the underlying layer it increases. In the water layer located above the shock layer, the processes of water mixing occur most intensively; this layer is called the active layer. Below the water jump layer, they become stable, since here the temperature decreases with depth, and salinity and density increase.[ ...]
Salinity fluctuations over time are insignificant. Annual fluctuations in the open parts of the oceans do not exceed 1% o, at a depth of 1500-2000 m salinity is almost unchanged (differences of 0.02-0.04% o). Significant fluctuations in salinity are observed in coastal areas, where fresh water inflow is more intense in spring, as well as in polar regions due to the processes of freezing and melting of ice.[ ...]
Fresh water reserves make up less than 2% of water resources. The average salinity of the waters of the World Ocean is 3.5 g / l (in the oceans 48-1015 tons of salt), drinking water should contain no more than 0.5 g / l, plants die from water containing 2.5 g / l of salt. Approximately 3/4 of the world's fresh water reserves are located in the ice of Antarctica, the Arctic, and glacial mountains. About 35 thousand sea ice and icebergs are included in the volume of the World Ocean. But 10-15 thousand icebergs break off annually only from the coast of the Arctic and Greenland. The annual river runoff is estimated at 41,000 km'. In Europe and Asia, where 70% of the population lives, only 39% of the world's river water reserves are concentrated. The world's most abundant lake Baikal (23 thousand km3) contains 20% of the world's surface fresh water reserves. Russia has the world's largest underground water storage - the West Siberian artesian basin with an area of 3 million km2, which is almost 8 times the area of the Baltic Sea.[ ...]
If the density of sea water is constant, then the ocean is said to be homogeneous. If the vertical density distribution depends only on pressure, then one speaks of a barotropic ocean. If the density of sea water is determined by temperature, salinity and pressure, then the ocean is considered baroclinic.[ ...]
For every 1000 g of ocean water, there are 35 g of salts, i.e. the salinity of the oceans averages 35%o (ppm).[ ...]
According to modern concepts, the salinity of the water of the seas and oceans is "primary", not changing during geological periods. Thus, the question of how water appeared on Earth requires study and clarification.[ ...]
Being an excellent solvent, water contains dissolved salts, gases, organic substances, the content of which in water can vary over a wide range. If the salt concentration is less than 1 g / kg, the water is considered fresh, with a salt concentration of up to 25 g / kg - brackish, and at a higher concentration - salty. In the ocean, the concentration of salts is about 35 g / kg, in fresh lakes, rivers 5-1000 mg / kg. Sea water is a multicomponent system that includes water molecules, anions and cations of salts, as well as many impurities. Good mixing of sea waters leads to equalization of the content of salt components in different parts of the World Ocean, and therefore one can speak of the constancy of the salt composition of ocean waters. To characterize salinity, the value S is used - salinity, which determines in grams the mass of dissolved solids contained in 1 kg of sea water, provided that bromine and iodine are replaced by an equivalent content of chlorine, all carbonic salts are converted into oxides, all organic substances are burned at a temperature of 480 ° FROM. This definition of salinity goes back to the previously accepted definition of salinity by chlorine content by titrating sea water. Salinity is measured in thousandths - ppm (% o). The constancy of the salt composition of sea water makes it possible to determine salinity by the content of one component.[ ...]
Similar expressions can be written for the salinity and density of sea water. The first term on the right side is the class of phenomena that are the subject of classical oceanography; the second term is heterogeneities related to the phenomenon of fine thermohaline structure; the third term is microturbulence according to Reynolds; tr - values of spatial and temporal scales delimiting the structural elements of water masses, due to the thin layered structure and turbulence. As a rule, the irregularity of vertical salinity profiles is greater than the irregularity of temperature distributions. Sea water has another interesting property. If in the atmosphere the rates of molecular diffusion of heat and moisture are almost the same, then the rates of diffusion of heat and salt in the ocean differ by two orders of magnitude (K = 1.4 10 3 cm2/s, 1 = 1.04 10 5 cm2/s), which leads to such a phenomenon as differential-diffusion convection, which is one of the mechanisms that determine the formation of a fine thermohaline structure of sea waters.[ ...]
Since information about the fields of temperature and salinity makes it possible to calculate currents only with respect to some given level, the velocities of stationary geostrophic currents in the ocean cannot be determined absolutely accurately. Therefore, it is also impossible to find the exact values of transfers and compare them with calculations using the Sverdrup ratio. However, some comparisons can still be made. So, for example, in Fig. 12.7.6 shows the currents of the North Atlantic at a depth of 100 m relative to currents at a depth of 1500 m. If we assume that the last currents are relatively weak, then Fig. 12.7.6 can be viewed as a picture of near-surface geostrophic currents. It shows many conspicuous coincidences with Fig. 12.7, a, which indicates that the effect of wind largely explains the pattern of surface circulation. On the other hand, significant differences, which can also be seen in these figures, indicate the importance of other factors, such as buoyancy forces. Worthington's calculations, in particular, show that the sinking of the waters in the Greenland Sea carries large masses of surface water there from the North Atlantic, and this significantly affects the overall circulation pattern.[ ...]
The uneven distribution of temperature, as well as salinity, is mainly created by mixing processes and sea currents. In the surface layers, within the active layer of the sea, the stratification of water masses is associated mainly with the processes of vertical exchange, and at depth the heterogeneity of oceanological characteristics is associated with the general circulation of the waters of the World Ocean. The heterogeneity of the waters of the oceans and seas, associated with the processes of vertical and horizontal exchange, determines the presence of intermediate cold or warm layers with low or high temperatures. These layers can be of convective (due to mixing) and advective origin. The latter are associated with the delivery (askes), i.e., horizontal intrusion, of water masses carried from outside by currents. An example is the presence of warm Atlantic waters in the entire central part of the Arctic Ocean, which can be traced at depths from 150–250 to 800–900 m. contacts arise? vertical gradients of oceanographic characteristics. The transition layer, in which the gradients of temperature, salinity, density and other properties are large, is called the jump layer. These layers may be temporary, seasonal, or permanent in the active layer and on its boundary with deep waters. Deep-water observations in various regions of the World Ocean (Fig. 14) show that in open regions, except for the polar regions, the temperature changes noticeably from the surface to a depth of 300-400 m, then up to 1500 m the changes are very insignificant, and from 1500 m it almost does not change. At 400-450 m the temperature is 10-12° C, at 1000 m 4-7° C, at 2000 m 2.5-4° C and from a depth of 3000 m it is about 1-2° C.[ ...]
If you do not touch dirty drains and poisonous plums, then since ancient times the waters are divided into salty and fresh. Salt waters, in comparison with fresh waters, contain an increased concentration of salts, primarily sodium. They are not suitable for drinking and industrial use, but are excellent for swimming and water transport. The salt composition of saline waters in different water bodies varies quite a lot: for example, in the shallow Gulf of Finland, the waters are less saline than in the Black Sea, and in the oceans, the salinity is much higher. I want to remind you that salt water is not necessarily sea water. There are known basins with exceptionally salty waters that have no connection with the sea, such as the Dead Sea in Palestine and the salt lake Baskunchak.[ ...]
Ripe lagenaria fruits are so light that they do not sink in salt water and are able to swim in the ocean for a long time without damage and without loss of seed germination. Since ancient times, accidentally falling into the Atlantic Ocean, the fruits of lagenaria, picked up by ocean currents, sailed from the coast of West Africa to Brazil or through the Pacific Ocean came from Southeast Asia to Peru, and from there the ancient inhabitants of South and North America spread throughout the continent .[ ...]
All of these factors determine the regime and changes in the salinity of the oceans and seas. Since salinity is the most conservative, established property of the waters of the World Ocean, we can also talk about the balance of salts. The incoming part of the salt balance is composed of the inflow of salts: a) with continental runoff, b) with atmospheric precipitation, c) from the Earth's cedar in the form of mantle degassing products, d) during the dissolution of rocks at the bottom of the oceans and seas.[ ...]
Hydrosphere - the water shell of the Earth, including oceans, seas, rivers, lakes, groundwater and glaciers, snow cover, as well as water vapor in the atmosphere. The Earth's hydrosphere is 94% represented by salt waters of the oceans and seas, more than 75% of all fresh water is conserved in the polar caps of the Arctic and Antarctica (Table 6.1).[ ...]
The salinity of the water of the World Ocean is 35 g/l, and at a salinity of 60 g/l, the main part of the cells cannot exist. The removal of salts by rivers into the ocean would double the concentration of salts every 80 million years, if not for the natural processes that remove salts from ocean water. Under these conditions, the relative stability of ocean salinity has been maintained for several hundred million years.[ ...]
biochemical properties. All biochemical processes of decomposition of wastewater organic matter in the seas and oceans proceed much more slowly than in freshwater basins. This is due to the fact that the concentration of salts in salt water is greater than in fresh water and therefore the osmotic pressure with which the microbial cell absorbs the nutrients necessary for its life decreases (Gaultier, 1954). Accordingly, the decrease in the value of BODz in sea water in the process of its self-purification occurs much more slowly than in fresh water.[ ...]
The temperate and tropical land belts, with their humid climate and developed biostrome, continue on the ocean as belts of high biological productivity. Subtropical desert belts of land with a poorly developed biostrome can be equally traced over the ocean. Ultimately, the lack of moisture both on land and in the ocean leads to a similar result for the bios - deserts appear, almost devoid of life”2.[ ...]
A small amount of work, of course, could not contain the huge information that is associated with the problem of water desalination. But we tried to show that the idea of obtaining fresh water from colossal salt waters of the seas and oceans occupied the minds of ancient thinkers and has now acquired real forms not only of technological, but also of technical solutions. Today, entire cities have grown on the sun-scorched, waterless land thanks to the found ways to desalinate sea water on an industrial scale.[ ...]
Regarding this project, M. Ewing's forecast about the consequences of the implementation of the dam construction is known. According to this forecast, the cessation of the flow of more saline waters into the Atlantic Ocean may, in three decades, lead to such a decrease in salinity in it that it will entail a complete change in the circulation of ocean waters, the result of which may ultimately be the cessation of the flow of warm waters of the Gulf Stream to the Arctic and cooling there with simultaneous warming in continental Europe. At one time, this forecast evoked a negative reaction from another well-known oceanologist, G. Stommel, who pointed out that on the basis of M. Ewing's assumptions, reverse processes could be predicted with the same success. This example is given in order to show the complexity and ambiguity of such forecasts in the current state of ocean science, even for stationary processes of water mass exchange.[ ...]
Various water masses are separated by frontal zones or frontal surfaces, in which the gradients of water mass characteristics become sharper. Quasi-stationary climatic frontal zones are the natural boundaries of the main water masses in the ocean. Five types of fronts are distinguished in the open ocean: equatorial, subequatorial, tropical, subpolar, and polar. The frontal zones are distinguished by the high dynamism of the processes occurring in them. In the coastal zone, in the estuarine zone, fronts are formed that separate the shelf or runoff waters from the waters of the deep part. The formation of one or another type of front depends on external conditions. According to the data of subsurface towing of temperature and salinity probes (measurements were carried out at a depth of 30 cm), with a front width of about 70 m, the salinity and temperature gradients are 2.2%o and 1.1° per 10 m, respectively. flow of fresh river water over saline and dense sea water. In the case of the inflow of Baltic waters into the lagoon, an intrusion front of heavy sea waters into the lighter waters of the lagoon is formed. When a wedge of saline sea waters propagates along a deep sea channel, a typical estuarine front is observed. A typical change in temperature, salinity and density at the front crossing is shown in fig. 6.5.[...]
This type of renewable energy resources is perhaps the most exotic, and the youngest in development time: the first technical ideas date back only to the 70s. our century. The renewal of this type of resource is associated with the transformation of part of the thermal energy of the ocean during the evaporation of water from its surface. This, as already noted, consumes about 54% of the total balance of energy coming from the Sun. When fresh water enters in the form of precipitation and river runoff back into the ocean, in the process of mixing with salt water, energy is released that is practically proportional to the magnitude of the change in the entropy of the fresh-ocean water system, which is a measure of the orderliness of this system. The change in entropy itself is an unobservable phenomenon, therefore, for example, in the mouths of rivers there are no noticeable manifestations of the release of additional energy. The energy of dissolution can be determined by first finding the value of the equilibrium osmotic pressure that occurs on a thin film that separates fresh and ocean water and has the ability to pass only water molecules. The penetration of H2O molecules continues until the pressure of the solution column balances the osmotic pressure, as a result of which equilibrium conditions are established between the solution and the solvent.[ ...]
At present, work on the organization of irrigated agriculture for growing perennial grasses and vegetables in the steppe zone continues, but small irrigated fields with an area of tens (not more than 200-300) hectares are being created, water intake is carried out from artificial reservoirs in which spring snow water accumulates. Irrigation from lakes is prohibited, where interference with the hydrological regime is especially dangerous, as it can lead to irreversible changes in their ecosystems (for example, the disappearance of fish and blooming water, i.e., the massive development of cyanobacteria, etc.). HYDROSPHERE (G.) - the water shell of the Earth, including oceans, seas, rivers, lakes, groundwater, glaciers. The structure of the G. of the Earth is shown in Table. 16. G. is 94% represented by the salty waters of the oceans and seas, and the contribution of rivers to the planet's water budget is 10 times less than the amount of water vapor in the atmosphere.[ ...]
Only the uppermost layers, 100–200 m thick, can be called true pelagic: in some places, foraminifera and pteropods make up more than 50% of them, while siliceous microfossils are rare. The increased salinity of the waters of the Red Sea probably prevents the development of radiolarians, and the appearance of these microorganisms in the section of Quaternary deposits corresponds to interglacial periods of high sea level, when the limitation of water exchange with the ocean was minimal. Coccolithophorites can withstand harsher conditions, but during the maximum of the last glaciation, salinity was so high that even the most tolerant forms eventually disappeared.