Salinity is the amount of dissolved solid minerals (salts), expressed in grams, in 1 kg of sea water. The thousandth part of a whole is called ppm and is indicated by the symbol %o. For example, if the salinity of ocean water is 35%o, this means that 1 kg (1000 g) of this water contains 35%o (ppm) of dissolved substances.

Salinity is one of the main characteristics of sea water; its value expresses the degree of concentration of all substances dissolved in water (mainly salts).

The value of salinity in a particular area of ​​the World Ocean depends on a number of factors: the influx of fresh water and the amount of precipitation, the intensity of water evaporation, the formation and melting of ice and water mixing processes.

As seawater evaporates, the salinity of seawater increases as the salts remain in solution. As sea ice melts, salinity decreases because sea ice typically has less salinity than
salinity of surrounding waters.

When sea ice forms, salinity increases due to the fact that only part of the salts pass into the ice.

What is the salinity of the waters of the World Ocean and its geographical distribution?

Salinity in different places, both on the surface and in the depths of oceans and seas, is not the same. The average salinity of the waters of the World Ocean is 35%.

In the open parts of the oceans, salinity changes little (from 32 to 37.9%o), in the seas it varies significantly more - from 2 (in the Gulf of Finland of the Baltic Sea) to 42%o (in the Red Sea).

The general pattern of changes in salinity across latitudes under the influence of precipitation and evaporation regimes is typical for all oceans: salinity increases in the direction from the poles to the tropics, reaches a maximum value around 20-25° northern and southern latitudes and decreases again in the equatorial zone.

The uniform change in salinity in the surface layers is disrupted by the influence of oceanic and coastal currents and enrichment fresh waters of large rivers. The highest salinity of the World Ocean (S = 37.9%o, not counting some seas, is west of the Azores.

The salinity of the seas differs the more from the salinity of the ocean, the less the seas communicate with it; it also depends on their geographical location, in particular on climatic conditions. The salinity of the seas is greater than that of the oceans: the Mediterranean - in the west 37-38%0, in the east - 38-39%0;

The salinity of the Red Sea is 37%o in the south, and up to 42%o in the north, in the Persian Gulf in the north the salinity is 40%o, in the eastern part - from 37 to 38%o.

Salinity: in the Sea of ​​Azov in the middle part is from 10 to 12%o, and off the coast - 9.5%o.

The salinity of water in the Black Sea, in the middle part, is from 10 to 12%o, and in the northwestern part - 17%o, with increasing depth of the sea, the salinity of the water increases to 22%o;

in the Baltic Sea with eastern winds - 10%o, with western and southwestern winds - from 10 to 22%o; in the Gulf of Finland near the island of Kotlin - 2%0; in the White Sea on the border with the Barents Sea it is 34-34.5%o, in Gorlo - 27-30%o, and in the middle part - from 24 to 27%o.

In the Caspian Sea, salinity is 12.8% o and in
The average salinity of the Aral Sea is 10.3%.

The salinity of the Russian Arctic and Far Eastern seas in areas remote from the coast is 29-30%.

With increasing depth, salinity changes only up to 1500 m, below this horizon and to the bottom - insignificantly and ranges from 34 to 35%.

In the polar regions, when ice melts, salinity increases with depth; when ice forms, the salinity of sea water decreases.

In temperate latitudes, the salinity of sea water changes little with depth; in the subtropical zone it quickly decreases to a depth of 100 m, in the tropical zone it increases to a depth of 100 m, then decreases to a depth of 500 m, after which it increases slightly to a depth of 1500 m, and below remains unchanged.

What is the significance of the salinity and density of sea water?

As the temperature decreases, the density of salty sea water increases, that is, the sea is saltier in winter than in summer! During autumn and winter cooling, the water on the sea surface becomes denser and heavier.
With further cooling, surface sea water, being denser and heavier, “sinks” and mixes with warmer and lighter deep water.

This feature of salty sea water helps to moderate the Earth's climate. When cooling 1 cu. see sea water at 19C 3134 cubic meters. see the air heats up by 1 °C.

The salinity of sea water increases vertical circulation in the oceans and seas. The air receives much more heat (thermal energy) from the salty waters of the World Ocean than it would receive if the ocean waters were fresh.

The intensity of freezing of sea water and the development of ice phenomena in the seas and oceans depend on salinity.

The horizontal and vertical distribution of seawater density promotes horizontal and vertical water circulation.

Knowing the vertical distribution of the density of sea water, it is possible to determine the direction and speed of currents, as well as the stability of a particular water mass: if the mass is unstable, then denser water lies above less dense water, and the waters will mix (vertical circulation).

The density of sea water is of great importance for ocean inhabitants. The stability of the water composition, which affects the distribution of organic and inorganic matter in the ocean, depends on it.

The density of water affects the draft of ships. When moving from ocean water to fresh water and vice versa, their draft can change up to 0.3 m. Therefore, for proper loading of ships in
ports and ensuring the safety of navigation, it is necessary to know the value of salinity and density at the port of loading and at the transition to the sea to the port of destination and take them into account correctly.

Several seas have the honor of being called “the saltiest”. The Dead and Red Seas are the undoubted leaders. Only Red is part of the World Ocean (MO, Ocean), connected to it by the Bab el-Mandeb Strait and the Gulf of Aden. The Dead Sea lake is a remnant of an ancient pool. This body of water on the Eurasian continent does not have a direct connection with the ocean. Let's find out which sea is the saltiest without delving into geographic “subordination.” Let’s compare the mineralization of the planet’s water bodies and find out what this indicator depends on. We will focus on the word “sea” in the names of geographical objects.

What property of water is called “salinity”?

Simple experience convinces us: there are impurities even in fresh lakes, rivers, and springs. If you pour some tap water into a saucer and leave it in the sun, the liquid will evaporate. There will be a white coating at the bottom - this is salt. We weigh it and get a value close to 2 g/l, calculated per 100 g of water - 0.2%. There are no impurities only in distilled water, but its consumption is harmful to the human body. The World Ocean contains an average of 35 g of salts per liter. Based on the color and transparency of the water, it is more difficult to recognize what is in front of us: a large fresh lake or a salt sea. A photo of a reservoir taken from a good angle, and even taste sensations help resolve this dilemma.

“Salinity” refers to the content of dissolved substances, this indicator is measured in ppm. The unit was specially introduced to study the composition of water; it was included in school and university geography textbooks. Let's simplify the explanation and relate the salinity indicator to the mass fraction as a percentage. Promile is a tenth of a percent, designated “‰”.

Sea water is a multicomponent solution

Mass (g) of common chemical elements in 1 liter of sea water:

• chlorine - 19.5;
• sodium - 10.8;
• magnesium - 1.3;
• sulfur - 0.9.

Less than 1 g is contained in the water of the seas of calcium, potassium, bromine, carbon, strontium, boron, fluorine, silicon. Chemistry experts will object that in the form of simple substances, the above-mentioned sodium and potassium are flammable, while sulfur, carbon and other substances are insoluble. In fact, during calculations, the mass fractions of elements are obtained, and they are in water in the form of ions: Na +, K +, Mg +, Ca +, Cl -, B -, S 2-, Br -, HCO 3-, SO 4 2- and other cations and anions.

Why are the solute levels different?

In the debate about which sea is the saltiest, several elementary truths are forgotten. Heraclitus, Plato and other ancient thinkers said that everything moves, you cannot enter the same water twice. The composition and amount of impurities in seas, rivers and lakes is constantly changing. The following factors influence the indicators:

• distance from the equator and the associated amount of solar radiation;
• climate and weather;
• amount of precipitation;
• surface and underground runoff;
• types and strength of rocks composing the bottom and shores;
• vital activity of organisms in water.

The salinity of the seas also depends on warm currents, because the solubility of most substances increases with rising temperatures. Coastal waters in areas where there is significant surface runoff from the mainland are desalinated, for example, in the deltas of the Nile, La Plata and other large rivers. As ice melts, salinity decreases. When ice cover forms, it increases.

Which sea is the saltiest in the world's oceans?

Many people remember from school that the salinity of water depends on evaporation. The higher it is, the more salts accumulate. In the polar latitudes in winter this pattern is violated. When ice forms, the water salinity increases, reaching record levels in the Greenland Sea for the northern part of the Moscow Region. Closer to temperate latitudes, the desalination influence of rivers and large amounts of precipitation are felt. Salinity reaches a maximum south of 45° N. w. and north of 10° S. w. This area contains the saltiest seas in the world:

• Red - 41‰;
• Mediterranean - 39‰;
• Arabian - 36‰.

Significant amounts of precipitation and the flow of great rivers reduce salinity in equatorial latitudes.

The Bab el-Mandeb Strait is the saltiest part of the MO

Having compared all the factors, we come to the final conclusion that the Red Sea is the saltiest. The body of water mentioned in the Old Testament is located between northeast Africa and the Arabian Peninsula. According to biblical legend, the Red Sea parted before the Israelites fleeing Egypt, and a wide passage appeared. Scientists have created a computer model that proves that the legend does not contradict the laws of physics.

About 41 g of impurities are dissolved in 1 liter of Red Sea water. Salinity increases from north to south, reaching its maximum value in the Bab el-Mandeb Strait. There is practically no river flow in this region; precipitation falls much less than water evaporates. Temperatures are consistently high throughout the year. The factors turned out to be favorable for the rich organic world of the Red Sea and the development of tourism on its shores.

Salty seas of Russia

Knowing the basic patterns that affect the content of dissolved substances, it is easier to determine which sea is the saltiest in Russia. In the north - Barents, in the east - Japanese. The salinity of water above the Arctic Circle varies significantly throughout the year. In the west of the Barents Sea, this figure reaches 35.0‰, but decreases significantly when moving east. The saltiest sea in Russia is the Sea of ​​Japan; the salinity of its water remains stable at around 34‰.

Dead Sea Lake - a natural phenomenon

The greatest influence on the content of dissolved substances is exerted by evaporation and the amount of precipitation. A combination of factors turned out to be favorable for the accumulation of salts in the lake on the Israeli-Jordanian border. The saltiest water is in the sea-lake, which is called Dead. The water is so dense that a person floats on its surface without effort.

Salinity levels are very high - from 300 to 370‰. The average content of dissolved substances is 33.7% (in 1 liter of water there are 337 g of salts). Not only the salty water, low location on land, but also the famous mud also made the lake famous. Highly mineralized sludge contains salts of about 300 g/kg.

Mineralogical composition of the Dead Sea

In total, the lake water contains dozens of mineral and organic components. We present data on the most common compounds indicating the mass fraction of the substance in the composition of all dissolved salts:

• magnesium chloride - 50.8%;
• calcium chloride - 14.4%;
• sodium chloride - 30.4%;
• potassium chloride - 4.4%.

After swimming in the waters of the Dead Sea, you should rinse off the concentrated salt solution so that it does not corrode the skin. Increased concentrations in mud were noted for the following biologically important substances: iodine, bromine, and hormone-like molecules. There are few sulfates in the water of the Dead Sea lake, but there are many bromides, which increases the healing effect of brine.

The famous salt sea lakes are disappearing

Media reports about the fate of the Dead and Aral Seas further fuel interest in the reservoirs. The surface of the Dead Sea is already 420 m below the level of the Ocean and is falling by about 1 m annually. According to researchers, in 40 years catastrophic changes similar to those that occurred with the Aral Sea may occur. For a long time, bodies of water have been constantly mentioned in answers to the question “which sea is the saltiest?” Dead Lake continues to conscientiously fulfill its obliging name. Salt water kills bacteria and prevents algae from growing.

The French writer Antoine de Saint-Exupéry wrote poetic lines about fresh water. He wrote about a liquid without color, taste or smell: “It is impossible to describe you, they enjoy you without knowing what you are,” “You are life itself.” It is a pity that the writer did not make equally poetic comparisons when he saw sea water. After all, the liquid environment of the animal body contains the same salts that were in the ancient ocean, which became the cradle of all life on Earth.

The topic of the second assignment on geography in the Unified State Exam format sounds like "Lithosphere. Atmosphere. Hydrosphere."

To complete this task, you need to know the salinity of most seas, the percentage composition of the atmosphere, be able to correlate temperature changes with an increase or rise in the earth's surface above sea level, understand the dependence of atmospheric pressure on the height of the earth's surface, and distinguish between relative and absolute humidity.

Required theory:

To begin with, it is worth clarifying that the task is divided into many subtypes, which becomes clear from its name. Therefore, the theory and procedure for performing the work vary significantly.

1 type of task: Atmosphere pressure.

The lower the earth's surface is to sea level, the higher the atmospheric pressure.

2nd task type: salinity of the seas.

Tropical seas are saltier than northern ones.

In general, it is better to memorize a ready-made table of salinity of the seas than to try to remember which of them can be classified as tropical and which not. Personally, I remembered one of the mnemotic rules when writing a story, somehow using the names of the seas in it. You can come up with your own more effective way.

The table below does not list all the seas, but I didn’t see any seas other than them on the samples.

TABLE OF SALINITY OF THE SEA:

Red sea

Mediterranean Sea

Barents/Caribbean/North Seas

Japanese Sea

Sea of ​​Okhotsk

Bering Sea

Black Sea

Baltic Sea

Caspian Sea

41.5 ppm

39.5 ppm

35 ppm

34 ppm

32 ppm

up to 32 ppm

up to 18 ppm

15 ppm

13 ppm

3 task type: percentage of gases in the atmosphere.

Naturally, there are quite a lot of gases in the atmosphere, and the percentage of some of them is very small. The ones in bold are worth remembering; I personally never came across the rest in test assignments.

PERCENTAGE CONTENT OF GASES IN THE ATMOSPHERE:

Nitrogen

Oxygen

Carbon dioxide

Hydrogen

4 task type: dependence of air temperature on the rise of the earth's surface above sea level.

The higher the earth's surface is above sea level, the lower the air temperature.

5 task type: relative and absolute air humidity.

Absolute humidity - water vapor content in 1 m^3 air [g]

Relative humidity [%]

This task can also be divided into subtypes, so everything should be shown clearly.

1. If the relative humidity in the table is the same, but it is necessary to determine the temperature, then:

The higher the absolute humidity (g), the higher the temperature.

2. If the air temperature in the table is the same, but it is necessary to determine the relative air humidity, then:

The more water vapor, the higher the relative humidity.

3. If the absolute humidity in the table is the same, but it is necessary to determine the air temperature, then:

The higher the relative humidity, the lower the air temperature.

Examples of the five Task Types:

1. atmospheric pressure.

At the points indicated by numbers in the figure, atmospheric pressure measurements are simultaneously taken. Arrange these points in order of increasing atmospheric pressure (lowest to highest).

The task can also be presented in the form of a table or graph, but the principle of its implementation does not change.

2. salinity of the seas.

Arrange the seas in order of decreasing salinity of surface waters (from highest to lowest).

1) Barentsevo;

2) Black;

3) Mediterranean.

3. percentage of gases in the atmosphere.

Arrange the gases in order of increasing their content in the atmospheric air (from lowest to highest).

1) Oxygen;

2) Nitrogen;

3) Hydrogen.

4. dependence of air temperature on the rise of the earth's surface above sea level.

At the points indicated by numbers in the figure, air temperature measurements are simultaneously taken. Arrange these points in order of decreasing air temperature (from highest to lowest).

The task can also be presented in the form of a table or other graph, but the principle of its implementation does not change.

5.2. relative and absolute air humidity.

(The air temperature is the same, but the absolute humidity is not).

At the points indicated in the table by numbers, measurements of the water vapor content in 1 m^3 of air and temperature are simultaneously carried out. Arrange these items in order of increasing relative humidity (lowest to highest).

5.3. relative and absolute air humidity.

(absolute humidity is the same, but relative humidity is different).

At weather stations 1, 2 and 3, the water vapor content in 1 m^3 of air is simultaneously measured and the relative humidity of the air is determined. The obtained values ​​are shown in the table. Arrange these weather stations in order of the increase in air temperature at them at the time of taking these measurements (from lowest to highest).

Everyone knows firsthand that the water in the sea is salty. But most people will most likely find it difficult to answer the question of which sea is the saltiest on the planet. However, hardly a person thought about why the sea is salty and whether there is life in the saltiest sea in the world.

The world ocean is a single whole natural organism. On the planet, they occupy two-thirds of the entire earth's space. Well, sea water, which fills the world's oceans, is considered the most abundant substance on the surface of the Earth. It has a bitter-salty taste; it differs from fresh sea water in its transparency and color, specific gravity and aggressive effect on materials. And this is explained simply - sea water contains more than 50 different components.

The saltiest seas in the world

Scientists know for sure which seas are saltier and which are less salty. The liquid in the seas has already been studied and literally broken down into its components. And it turned out that the salty seas in Russia occupy the highest positions in the salinity ranking. So, the main contender for the status of the saltiest is the Barents Sea. This is because throughout the year the salinity of the surface layers fluctuates around 34.7-35 percent, however, if you deviate to the north and east, the percentage will decrease.

The White Sea is also characterized by high salinity. In the surface layers the figure stopped at 26 percent, but at depth it increases to 31 percent. In the Kara Sea, salinity is about 34 percent, however, it is heterogeneous and at the mouths of inflowing rivers the water becomes almost fresh. Another one of the saltiest seas in the world can be called the Laptev Sea. At the surface, salinity is recorded at 28 percent. The figure is even higher - 31-33 percent - in the Chukchi Sea. But this is in winter, in summer the salinity drops.

Which sea is saltier

By the way, everyone’s favorite Mediterranean Sea can also compete for the status of the saltiest in the world. Its salinity ranges from 36 to 39.5 percent. In particular, because of this, there is a weak quantitative development of phyto and zooplankton in the sea. However, despite this, the sea is home to a large number of fauna. Here you can find seals, sea turtles, 550 species of fish, about 70 endemic fish, crayfish, as well as octopuses, crabs, lobsters, and squid.

Certainly not saltier than the Mediterranean is another famous sea - the Caspian Sea. The Caspian Sea boasts a rich fauna - 1809 species. The sea is home to most of the world's sturgeon stocks, as well as freshwater fish (pike perch, carp and roach). The flora is also very rich - there are 728 plant species in the Caspian Sea, but, of course, algae predominate. An interesting fact: in Karakalpakstan there is a unique natural object - the Aral Sea. And its distinctive feature is that it can be called the second Dead Sea. Just half a century ago, the Aral Sea had standard salinity. However, as soon as water from the sea began to be taken for irrigation, salinity began to increase, and by 2010 it had increased 10 times. The Dead Sea is called not only because of its salinity, but also because many of the inhabitants of the Aral Sea became extinct as a protest against rising salinity levels.

Why are the seas salty?

Why are the seas salty? This question has interested people since ancient times. For example, according to a Norwegian legend, at the bottom of the sea there is an unusual mill that constantly grinds salt. Similar stories exist in the fairy tales of the inhabitants of Japan, the Philippines and Karelia. But according to the Crimean legend, the Black Sea is salty due to the fact that girls caught in Neptune’s net are forced to weave white lace for the waves at the bottom for centuries and constantly cry about their native land. Because of the tears, the water became salty.

But according to a scientific hypothesis, salt water became a different path. All water in the seas and oceans comes from rivers. However, fresh water flows in the latter. On average, 35 grams of salts are dissolved in one liter of the World Ocean. According to scientists, every grain of salt is washed out of the soil by river waters and sent to the sea. Over centuries and millennia, more and more salt has accumulated in the World Ocean. And she can’t go anywhere.

There is a version that the water in the oceans and seas was originally salty. The first body of water on the planet was supposedly filled with acid rain that fell to the earth as a result of a major volcanic eruption early in the life of the planet. Acids, according to scientists, corroded rocks and entered into chemical compounds with them. As a result of chemical reactions, salt water appeared, which now fills the World Ocean.

The saltiest sea in the world

The saltiest sea in the world is called the Red Sea. One liter of its water contains 41 grams of salts. The sea has only one source of water - the Gulf of Aden. Over the course of a year, through the Bab-El Mandeb Strait, the Red Sea receives a thousand cubic kilometers of water more than it is removed from the sea. Therefore, according to researchers, it takes about 15 years for the waters of the Red Sea to be completely renewed.

The salty Red Sea is very well and evenly mixed. In winter, surface waters cool and sink, raising warm waters from the depths of the sea. In summer, the water evaporates from the surface, the remaining water becomes salty and heavy, and therefore sinks down. It is not so salty water that rises up. Thus, the water is mixed. The sea is the same in salinity and temperature everywhere except in the depressions.

By the way, the discovery of depressions in the Red Sea with hot brine in the 60s of the last century was a real discovery for scientists. The brine in such depressions has a temperature of 30 to 60 degrees Celsius, and it rises by a maximum of 0.7 degrees per year. It turns out that the water is heated from the inside by “earthly” heat. And scientists say that the brine does not mix with sea water and differs from it in chemical characteristics.

There is no coastal runoff (rivers or rainfall) in the Red Sea. As a result, there is no dirt from the land, but there is crystal clarity of the water. All year round the temperature stays at 20-25 degrees. This determined the wealth and uniqueness of marine life in the sea.

Why is the Red Sea the saltiest? Some say the saltiest is the Dead Sea. Its salinity is 40 times higher than the salinity of the Baltic Sea and 8 times the Atlantic Ocean. However, it is impossible to call the Dead Sea the saltiest, but it is considered the warmest.

The Dead Sea is located in Jordan and Israel in Western Asia. Its area is more than 605 square kilometers with a maximum depth of 306 meters. The only river that flows into this famous sea is the Jordan. There is no outlet to the sea, so according to science it would be more correct to call it a lake.
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1st place.

Dead Sea. In fact, this body of water can be called a lake, because it does not communicate with other seas or the ocean. Nevertheless, everyone is accustomed to calling it the sea. Well, so be it. The Dead Sea has an incredible salinity - 33.7%. That is, every 100 g of water contains 33.7 g of salt.

Thanks to this incredible ratio, it is impossible to drown in this sea, because the body always strives to rise to the surface. The Jordan River and several small streams flow into it, but this influx of water is clearly not enough to maintain the level of the reservoir. By the way, its level drops by 100 cm every year, which in the future is fraught with environmental disaster.

2nd place.

Red sea. The percentage of salt in water is approximately 8 times less than that of the leader - 4.3%. It is noteworthy that no rivers flow into this reservoir, therefore, silt and sand do not enter the sea from the outside, which means its water is clean and transparent. Why is the salinity increased? Because this area receives little rainfall, and clean water comes only from the Gulf of Aden.

Plus, incredible evaporation. The Red Sea loses up to 1 cm of its level every day, and the amount of salt does not change significantly; on the contrary, its concentration increases slightly. Poor water exchange is the true cause of increased salinity.

3rd place.

Mediterranean Sea.
It washes the shores of Africa, Asia and Europe. That's why they called him that. It has a salinity of 3.9%. Several large rivers flow into the sea. Water circulation occurs under the influence of the wind and due to the transfer of water by the Canary Current. The salinity of the reservoir regularly increases due to strong evaporation, and the density of the water varies significantly depending on the time of year.

4th place.

Caribbean Sea. In addition to the fact that this is the most “pirate” sea, it also occupies fourth place in the “salinity hit parade”. This figure is 3.5%. And in terms of its hydrological composition, this reservoir is quite homogeneous. That is, there are no sharp fluctuations in temperature and in the degree of salinity of its individual sections.

Several large rivers flow into the Caribbean Sea. The tropical climate makes this sea basin attractive to tourists. Just keep in mind that hurricanes very often rage in the northern part of the reservoir, causing a lot of inconvenience to residents of coastal settlements.

5th place.

Barencevo sea. Located on the edge of the Arctic Ocean. It has a salinity of 3.5%. In ancient times it had many names, because each nation called this body of water in its own way. Only in 1853 did the sea receive its final name - Barents, in honor of the Dutch sailor V. Barents.

Naturally, in the middle of the sea its salinity is higher than at the outskirts. This is explained by the fact that it is washed by slightly salty seas: the Norwegian, White and Kara. And in the north, the icy ocean significantly dilutes the concentration of sea water, because it itself does not shine with particular salinity, which is explained by the regular melting of ice.

6th place.

North Sea. Its salinity has different values, on average this value is 35%. The fact is that the North Sea in the east borders the slightly salty Baltic, and the rivers Thames, Elbe, Rhine and others also have an influence on this indicator. It washes the shores of many European countries where the largest ports are located - London, Hamburg, Amsterdam, etc.

7th place.

Japanese Sea. The salinity indicator is 3.4%. In the northern and western parts of the reservoir it is much colder than in the southeast. The Sea of ​​Japan is not a tourist destination. It is rather of industrial importance for some countries. He loves to scare sailors with typhoons, especially in the fall.

8th place.

Sea of ​​Okhotsk. It has a salinity of 3.2%. In winter it freezes in the northern part, despite the increased salinity of the water, which, by the way, is much lower in coastal areas.

9th place.

Black Sea. The salinity of this body of water varies greatly. For example, in the lower layer this figure is 2.3%, and in the upper layer, where increased water circulation occurs, the salinity is 1.8%. It is noteworthy that at a depth of 150 m there is no longer any life. This is explained by the increased content of hydrogen sulfide in the water.

10th place.

Sea of ​​Azov. The average salinity of the sea is 1.1%. In the 20th century, many rivers feeding this reservoir with water were blocked by dams, therefore, the flow of water and its circulation decreased significantly. It is noteworthy that this is the shallowest sea in the world; its maximum depth does not reach 14 m. It has a tendency to freeze in its northern part.