11.07.2007 15:00

The world ocean is a single integral natural body that occupies 2/3 of the entire area of ​​the globe. Sea water, of which it is composed, is the most abundant substance on the surface of the Earth. It differs from fresh water in its bitter-salty taste, specific gravity, transparency and color, more aggressive effect on building materials and other properties. This is explained by the content in sea ​​water more than 50 different components.

The total content of solid dissolved substances in 1 kg of sea water and expressed in tenths of a percent (ppm ‰) is called salinity. Average salinity sea ​​water on the ocean surface ranges from 32 to 37‰, in natural layers from 34 to 35‰. In some seas there is a significant deviation from these average values. Thus, the salinity of the Black Sea is 17-18‰, the Caspian Sea is 12-13‰, and the Red Sea is up to 40‰. Theoretically, sea water contains all known chemical elements, but their weight content is different.

Of the total amount of dissolved substances, 99.6% are halide salts of sodium, potassium, magnesium and sulfates of magnesium and calcium, and only 0.4% of the salt composition accounts for the remaining substances. The table shows that only 13 elements of the “periodic table” are contained in quantities of more than 0.1 mg/l. Even such important elements for many processes in the ocean (especially for the life of marine organisms) as phosphorus, iodine, iron, along with calcium, sulfur, carbon and some others, are contained in quantities less than 0.1 mg/l. Seawater also contains organic substances in the form of living matter and in the form of dissolved “inert” organic substances, amounting to a total of about 2 mg/l.

The salt composition of sea water differs sharply from the salt composition of river water, but is close to the waters released during volcanic eruptions or hot springs fed from the deep interior of the Earth. River water also contains dissolved substances, the amount of which very much depends on physical and geographical conditions.

How larger value evaporation, the greater the salinity of sea water, since salts remain during evaporation. Changes in salinity are greatly influenced by oceanic and coastal currents, the removal of fresh water by large rivers, and the mixing of ocean and sea waters. In depth, fluctuations in salinity occur only up to 1500 m; below that, salinity changes insignificantly.

The saltiest sea in the world - Red. 1 liter of its water contains 41 g of salts. On average, no more than 100 mm falls over the sea per year atmospheric precipitation, while the amount of evaporation from its surface reaches 2000 mm per year. In the complete absence of river flow, this creates a constant deficit water balance sea, for the replenishment of which there is only one source - the flow of water from the Gulf of Aden. During the year, approximately 1,000 cubic meters are introduced into the sea through the Bab-el-Mandeb Strait. km of water is more than is removed from it. Moreover, according to calculations, it takes only 15 years for the complete exchange of Red Sea waters.

In the Red Sea, the water is very well and evenly mixed. In winter, surface water cools, becomes denser and sinks down, and rises up warm waters from the depths. In summer, water evaporates from the surface of the sea, and the remaining water becomes saltier, heavier and sinks. In its place rises less salty water. Thus, all year round the water in the sea is intensively mixed, and throughout its entire volume the sea is the same in temperature and salinity, except in the depressions.

Detection depressions with hot brines in the Red Sea was a real scientific discovery in the 60s of the twentieth century. To date, more than 20 such depressions have been discovered in the deepest areas. The brine temperature is in the range of 30-60°C and increases by 0.3-0.7°C per year. This means that the depressions are heated from below by the internal heat of the Earth. Observers diving into the depressions on underwater vehicles, said that the brines do not merge with the surrounding water, but are clearly distinct from it and look like silty soil covered with ripples, or like swirling fog. Chemical analyzes have shown that the content of many metals in brines, including precious ones, is hundreds and thousands of times higher than in ordinary sea water.

The absence of coastal runoff (or, more simply, rivers and rain streams), and therefore dirt from the land, ensures fabulous water transparency. Water temperature is stable all year round- 20-25°C. All these factors determined the richness and uniqueness sea ​​life in the Red Sea.

Dead Sea located in Western Asia in Israel and Jordan. It is located in a tectonic depression formed as a result of the so-called Afro-Asian fault, which occurred in the era somewhere between the end of the Tertiary and the beginning of the Quaternary period, that is, more than 2 million years ago.

Square Dead Sea 1050 sq. m, depth 350-400 meters. It flows into the only river Jordan, but nutrition also comes from numerous mineral springs. The sea has no outlet and is drainless, therefore it is more correct to call it a lake.

The surface of the Dead Sea is 400 meters below the level of the World Ocean (the deepest low point Globe). In its current shape, the Dead Sea has existed for more than 5,000 years, during which time a sedimentary silt layer more than 100 meters thick has accumulated on its bottom.

Over the years, under the hot rays of the sun, the water of the Dead Sea evaporated and minerals accumulated, increasing the salinity of the sea. These conditions largely determine the unique composition of the water and mud of the Dead Sea.

In terms of the composition of its salts, the Dead Sea differs sharply from all other seas on the planet. The salinity of the Dead Sea is 8 times higher than the salinity of the Atlantic Ocean and 40 times the Baltic Sea. While in the waters of other seas the sodium chloride content makes up 77% of the total salt composition, in the waters of the Dead Sea its share is 25-30%, and the share of magnesium salts accounts for up to 50%, the bromine content is a record: 80 times higher, than in the Atlantic Ocean.

High salinity waters of the Dead sea ​​explains its high density, which is 1.3-1.4 g/cm 3 . The increase in water density with depth apparently creates the pushing effect when immersed in water. The water of the Dead Sea has a high content of trace elements such as copper, zinc, cobalt and others. Features of the Dead Sea water include: high value pH equal to 9.

Large-scale features of salinity distribution in the World Ocean have good stability. Over the past 50 years, no significant changes have been noticed in the salt state of the World Ocean, and it is generally accepted that its state is on average stationary.

Oceanographic technician
A.V. Timoshkova

Red and Dead Sea

The saltiest seas in the world's oceans are two: the Red and the Dead. At the same time, it is difficult to consider the Dead as a sea as such. It's more of a lake than a sea. Therefore, they are placed alternately in 1st and 2nd places when answering the question about the saltiest sea on the planet.

The world ocean is a single integral natural body that occupies 2/3 of the entire area of ​​the globe. Sea water, of which it is composed, is the most abundant substance on the surface of the Earth. It differs from fresh water in its bitter-salty taste, specific gravity, transparency and color, more aggressive effect on building materials and other properties. This is explained by the content of more than 50 different components in sea water.

Theoretically, sea water contains all known chemical elements, but their weight content is different.

Of the total amount of dissolved substances, 99.6% are halide salts of sodium, potassium, magnesium and sulfates of magnesium and calcium, and only 0.4% of the salt composition accounts for the remaining substances. The table shows that only 13 elements of the “periodic table” are contained in quantities of more than 0.1 mg/l. Even such important elements for many processes in the ocean (especially for the life of marine organisms) as phosphorus, iodine, iron, along with calcium, sulfur, carbon and some others, are contained in quantities less than 0.1 mg/l. Seawater also contains organic substances in the form of living matter and in the form of dissolved “inert” organic substances, amounting to a total of about 2 mg/l.

What determines the salinity of the sea?

The salt composition of sea water differs sharply from the salt composition of river water, but is close to the waters released during volcanic eruptions or hot springs fed from the deep interior of the Earth. River water also contains dissolved substances, the amount of which very much depends on physical and geographical conditions.

The greater the amount of evaporation, the greater the salinity of sea water, since salts remain during evaporation. Changes in salinity are greatly influenced by oceanic and coastal currents, the removal of fresh water by large rivers, and the mixing of ocean and sea waters. In depth, fluctuations in salinity occur only up to 1500 m; below that, salinity changes insignificantly.

Large-scale features of salinity distribution in the World Ocean have good stability. Over the past 50 years, no significant changes have been noticed in the salt state of the World Ocean, and it is generally accepted that its state is on average stationary.

Composition and features of the Red Sea

Red sea. 1 liter of its water contains 41 g of salts. On average, no more than 100 mm of atmospheric precipitation falls over the sea per year, while the amount of evaporation from its surface reaches 2000 mm per year. At complete absence In the river flow, this creates a constant deficit in the water balance of the sea, for the replenishment of which there is only one source - the supply of water from the Gulf of Aden. During the year, approximately 1,000 cubic meters are introduced into the sea through the Bab-el-Mandeb Strait. km of water is more than is removed from it. Moreover, according to calculations, it takes only 15 years for the complete exchange of Red Sea waters.

In the Red Sea, the water is very well and evenly mixed. In winter, surface waters cool, become denser and sink, while warm waters from the depths rise upward. In summer, water evaporates from the surface of the sea, and the remaining water becomes saltier, heavier and sinks. Less salty water rises in its place. Thus, all year round the water in the sea is intensively mixed, and throughout its entire volume the sea is the same in temperature and salinity, except in the depressions.

The discovery of depressions with hot brines in the Red Sea was a real scientific discovery in the 60s of the twentieth century. To date, more than 20 such depressions have been discovered in the deepest areas. The brine temperature is in the range of 30-60°C and increases by 0.3-0.7°C per year. This means that the depressions are heated from below by the internal heat of the Earth. Observers who dived into the depressions on submersibles said that the brines do not merge with surrounding water, but clearly differ from it and look like muddy soil covered with ripples, or like swirling fog. Chemical analyzes have shown that the content of many metals in brines, including precious ones, is hundreds and thousands of times higher than in ordinary sea water.

The absence of coastal runoff (or, more simply, rivers and rain streams), and therefore dirt from the land, ensures fabulous water transparency. The water temperature is stable all year round - 20-25°C. All these factors have contributed to the richness and uniqueness of marine life in the Red Sea.

Facts about the Dead Sea

Dead Sea located in Western Asia in Israel and Jordan. It is located in a tectonic depression formed as a result of the so-called Afro-Asian fault, which occurred in the era somewhere between the end of the Tertiary and the beginning of the Quaternary period, that is, more than 2 million years ago.

The area of ​​the Dead Sea is 1050 square meters. m, depth 356 meters. The only river Jordan flows into it, but it is also fed by numerous mineral springs. The sea has no outlet and is drainless, therefore it is more correct to call it a lake.

The surface of the Dead Sea is 400 meters below the level of the World Ocean (the lowest point on the globe). In its current shape, the Dead Sea has existed for more than 5,000 years, during which time a sedimentary silt layer more than 100 meters thick has accumulated on its bottom.

Over the years, under the hot rays of the sun, the water of the Dead Sea evaporated and minerals accumulated, increasing the salinity of the sea. These conditions largely determine the unique composition of the water and mud of the Dead Sea.

Dead Sea salinity

In terms of the composition of its salts, the Dead Sea differs sharply from all other seas on the planet. The salinity of the Dead Sea is 8 times higher than the salinity of the Atlantic Ocean and 40 times the Baltic Sea. While in the waters of other seas the sodium chloride content makes up 77% of the total salt composition, in the waters of the Dead Sea its share is 25-30%, and the share of magnesium salts accounts for up to 50%, the bromine content is a record: 80 times higher, than in the Atlantic Ocean.

The high salinity of the Dead Sea water explains its high density, which is 1.3-1.4 g/cm3. The increase in water density with depth apparently creates the pushing effect when immersed in water. The water of the Dead Sea has a high content of trace elements such as copper, zinc, cobalt and others. The peculiarities of the Dead Sea water include a high pH value of 9.

Since childhood, we know that the water in the ocean is always salty. But which ocean is the saltiest in the world? This is actually a pretty important scientific question. The salinity of the waters of the World Ocean has been studied for a long time. It is now known exactly which ocean on Earth is the saltiest. It is the Atlantic Ocean, or, as it is called, the Atlantic. Let's consider its features.

What size is the Atlantic?

The Atlantic Ocean has an area exceeding 106.5 million square meters. km. The depth of the most salty ocean on Earth exceeds 3,600 meters. The water of the Atlantic Ocean has a salinity of approximately 35%, which is an order of magnitude higher than that of other oceans. Interesting feature there was a uniform distribution of salinity. Moreover, it is the only one of its kind on the planet, which only confirms its title as the saltiest.

What is the explanation for high salinity?

The high salinity of the Atlantic is due to a number of reasons. High salinity is not found everywhere. Where the waters of the North Atlantic Current flow, lower salinity levels are recorded.

The Atlantic even has fresh springs located underground. Moreover, this is one of the mysteries of the natural world, because water rises from the depths of the ocean.

What other salty oceans are there in the world?

The Indian Ocean is the saltiest after the Atlantic. In certain areas he is even capable of breaking the leader's record. The total salinity is 34.8%.

The most salt-rich areas of the Indian Ocean are those that experience the least annual rainfall. In winter, the Indian Ocean becomes less salty due to the monsoon current bringing fresh water. A region forms near the equator where the Indian Ocean exhibits less salinity.

The largest ocean in the world (the Pacific) is also rich in salt. The salt content of its waters exceeds 34%, and tropical regions can show salinities higher than 35.6%. The world's largest ocean also has salinity above 30% in areas where glaciers melt.

The coldest - the Arctic - has a salinity of 32%. Characteristic feature This ocean became lower in salinity in the upper layer. This is due to the desalination of rivers and the melting of ice. The lower layer of the ocean is saltier, containing warm water with a high percentage of salt content. It comes straight from the Greenland Sea. The deep layer of the Arctic has an average level of salinity compared to the third and second layers.

Interesting facts about the Atlantic Ocean

Previously, the Atlantic Ocean carried the most different names. For example, the ancient Greeks spoke of it as “the sea beyond the Pillars of Hercules.” It was also called the "sea of ​​darkness" and the Western Ocean. Its current name is the most salty ocean planets received only in the 16th century thanks to the cartographer Martin Waldseemüller. This man became famous not only for his description of the Alps, but also for the first map of the geographical world on which latitude and longitude were plotted.

It is difficult to say why this name was given. There are many supporters who believe in the existence of Atlantis - a sunken continent that was once located in the Atlantic Ocean. The main version is based on the myth of the Titan Atlas, who held the sky on his shoulders.

Scientists around the world consider the most important gift of the Atlantic to be its warm Gulf Stream. Thanks to it, it is possible to provide enormous energy production comparable to thousands nuclear power plants. The high salinity of the Atlantic Ocean has not become a negative factor; the flora and fauna here is no less rich than Pacific Ocean.

Which sea is the saltiest in the world

One might think that since the Atlantic Ocean is the most saturated with salt on the planet, then it is in it that one should look for the most salty sea. However, it is not.

Many believe that the Dead Sea is considered the richest sea in the world. However, in fact, this title is assigned to the Red Sea, which is located in Indian Ocean. Its salinity level exceeds 40%. Moreover, the reason for this level of salt content was the large volume of evaporating water. There is little sediment in the area adjacent to the saltiest sea in the world, so there is really a lot of salt in it. Also, no rivers flow into the Red Sea, but what a rich world of flora and fauna it has. The second place is occupied by the Mediterranean Sea, which has a salinity of about 39%. As in the previous case, the reason lies in the evaporation of moisture. Common list The saltiest seas in the world are as follows:

• Red;
• Mediterranean;
• Black;
• Azovskoe.

Near the Black Sea, salinity reaches 18%. On the surface lies a layer enriched with oxygen. The depth is very salty and dense, containing virtually no oxygen. The Azov Sea has an indicator of 11%, the northern part is the least saturated with salt, so with the onset of cold weather it easily freezes. Feature Sea of ​​Azov There was an extremely uneven distribution of salt.

What is the saltiest lake in the world?

Here we come to Dead Sea, which is actually a lake, since it has no access to the World Ocean.

The salinity of the Dead Sea exceeds 300%. There is a medical resort next to it, but there is no living life as such in the saltiest lake in the world. Note that the Dead Sea is considered the most popular among the most salt-rich lakes, but there are others:

• Assal;
• Baskunchak;
• Elton;
• Don Juan;
• Great Salt Lake.

Lake Tuz, for example, is located in Turkey. Large mines are located here, where a significant part of the country's salt reserves is mined. Lake Assal, which is located in Africa, has a salinity level exceeding 300%, as does the Dead Sea. In Russia there is Lake Baskunchak, the salinity of which reaches 300%. Raw materials important for the food industry are also actively mined here. Lake with beautiful name Elton is also located in Russia, and its salinity is about 500%, but the average is only 300%. It is considered the largest salt lake in Europe. The presence of a high concentration of salt ensures that the lakes do not freeze. However, such indicators are destructive for flora and fauna, so the saltiest lakes on the planet simply have no inhabitants. Big was no exception salt Lake United States of America. Thus, we can determine that not only the Dead Sea claims its title, scientists regularly argue about replacing it on this pedestal with Lake Don Juan, which is located in Antarctica. Its salinity index exceeds 350%. A reasonable question may arise, which lake is the least saline? It was Russian Baikal, with an indicator of 0.001%. Thanks to this and its purity, Baikal became famous as a lake with crystal clean water.

Meaning of the Atlantic Ocean

What is the significance of the world's saltiest ocean? The Atlantic Ocean is an example of maximum development economic activity. Shipping, oil and gas production, fisheries, biological resources. Many transoceanic routes, passenger transport and large ports located on the coasts are striking examples of economic development.

The value of the Atlantic Ocean to the world stems from its enormous mineral resource base. Most of it, scientists believe, has already been explored. At the same time, the North and Caribbean Seas and the Bay of Biscay attract businessmen seeking to develop new oil and gas fields. The Atlantic is incredibly important for countries such as Mexico, England, Norway. Its biological potential is very great. For a long period the ocean was used for mining commercial fish, which led to the depletion of biological resources.

What problems does the Atlantic Ocean have?

The Atlantic is part of the World Ocean, so its problems can affect the whole world. The waters of the Atlantic have been polluted by humans for a long time. Oil, plastic waste that does not decompose even after decades, constant fishing, a detrimental effect on the ecosystem as a whole. All this has had a detrimental effect on the Atlantic, which is under serious threat.

The invention of the harpoon cannon led to the mass extermination of whales; there are now regular debates about the renewal of the moratorium for countries around the world, but the International Whaling Commission actively opposes this, giving relief only to Denmark, Japan and Iceland.

The worst disaster for the Atlantic was the explosion and collapse of the Deepwater Horizon oil platform. Approximately 5 million barrels of oil spread across the Atlantic, polluting over a thousand miles of coastline. This case shocked the whole world and led to massive lawsuits from fishermen who lost important work. The proceedings lasted a very long time, and some legal disputes have not yet been resolved. Meanwhile, the disaster killed more than 6,800 animals, including sea turtles, dolphins, and other mammals.

The Atlantic has its own large garbage patch, similar to the Pacific. It consists of plastic, is in the waters Sargasso Sea. The situation with radioactive contamination is even more complicated. The Atlantic accepted tons of waste from nuclear power plants, and a number of research centers dumped radioactive waste into rivers and coastal waters. The depths of the Atlantic conceal so many dangerous chemical substances that you can’t count them all. The result of economic activity was the pollution of several seas, including the Irish, Mediterranean, Northern and others. At the end of the last millennium, Atlantic waters received more than 5,000 tons of radioactive waste. Over 30 years, the United States buried more than 14 thousand containers containing radioactive elements, which led to high level infection. The sunken ship, which contained about 70 tons of sarin, was also “buried” at the bottom of the Atlantic. Germany dropped 2,500 barrels containing industrial waste. Soviet Union 2 nuclear submarines were sunk.

The Atlantic is of particular importance to human economic activity and has many threatened ecosystems. The ocean needs to be carefully managed and conserved with the participation of all countries that use its resources.

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 of 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 pure 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 - here the real reason 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 flow into the sea large rivers. 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. Tropical climate makes the pool of this sea 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 meanings 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 top layer, where there is increased water circulation, 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.

Sea water, having dissolved a lot of chemical compounds billions of years ago, was transformed into a solution containing many unique microcomponents. One of the main characteristics of sea water is its salinity. The Mediterranean Sea is the saltiest on the planet after the Red Sea.

A little history

The Mediterranean Sea, according to scientists, was once part of the Tethys, an ancient ocean that stretched from America to Asia.

Five million years ago, due to a severe drought, the sea consisted of many lakes and began to flood only after the end of the drought, many years later. This was facilitated by a gigantic waterfall, which cut the barrier that served as a barrier between the sea and Atlantic Ocean. Gradually, as the sea filled with the waters of the Atlantic Ocean, this obstacle disappeared, and the Strait of Gibraltar was formed.

Characteristic

The Mediterranean Sea is located between Africa and Europe, and its outlines are constantly changing. To date:

• its area is 2.5 million km 2;
• water volume - 3.6 million km 3;
• average depth - 1541 m;
• maximum depth reaches 5121 m;
• water transparency 50-60 m;
• salinity Mediterranean Sea in percentage places it reaches 3.95%;
• total annual 430 km 3 .

This is one of the warmest and saltiest areas of the World Ocean.

The Mediterranean Sea received its name from its location among the lands that made up the entire world known to the ancients. The sea in the middle of the Earth - that’s what the ancient Greeks called it, the Romans called it the Inland Sea, or Ours . Big green water- this is how the ancient Egyptians dubbed the reservoir.

Water composition

Sea water is not just H 2 O, but a solution of a myriad of substances, where many are combined in various formulas chemical elements. Of these, the most a large number of consists of chlorides (88.7%), among which the leader is NaCl - ordinary table salt. Sulfuric acid salts - 10.8%, and only 0.5% of the rest of the water composition is formed by other substances. These proportions determine the salinity of the Mediterranean Sea. The indicator is 38‰. This makes it possible to obtain table salt from sea water by evaporating it.

Over the course of many years of development of life on Earth, sea water became a supplier of salt, transforming into salt layers. Some of the largest in Europe are located in Sicily - the largest

Salt deposits can form at different depths, which sometimes reach 1 km, and in some cases these are salt lakes at the level of the Earth's surface - the Uyuni salt marsh, a dry salt lake.

Oceanographers have found that the World Ocean contains 48 quadrillion tons of salt, and even with its constant extraction, the composition of sea water will not change.

Salinity concept

When determining the salinity of the Mediterranean Sea, as well as other bodies of water, the mass of salts in grams contained in one kilogram of sea water is taken into account.

It is calculated in ppm and is due to the fact that a large volume of river water or melted continental glaciers enters the seas. Low salinity equatorial zone caused by tropical rains, which desalinate the water.

Salinity changes with increasing depth. Beyond 1500 meters there is practically no water.

To take a sample and measure it, special samplers are used, which allow you to take samples from different depths and from different water layers.

Where does so much salt come from in sea water?

For some time, scientists were of the opinion that the salt was brought by rivers, but this hypothesis was not confirmed. The only assumption that is now held is that the ocean became salty during the process of its birth and transformation, since ancient animals could not live in fresh or slightly salty water. At the bottom of the Mediterranean Sea, near the Greek city of Zakynthos, organized structures were found that were more than three million years old, but what the salinity of the Mediterranean Sea water was in those distant times in percentage is unknown.

Academician V.I. Vernadsky believed that sea ​​inhabitants- animals and plants - extracted silicon salts and carbon dioxide from the depths of the sea, which were brought by rivers to form their shells, skeletons and shells. And as they died, these same compounds settled on the seabed in the form of organic sediments. Thus, marine life has maintained the salt composition of sea water unchanged for centuries.

What causes salinity?

All seas are part of the ocean. But there are seas that break deep into the land and are connected to the ocean only by a narrow strait. These seas include:

• Mediterranean;
• Black;
• Azovskoe;
• Baltic;
• Red.

All of them can be either very salty, because they are influenced by hot air, or almost fresh due to the rivers flowing into them, which dilute them with their water.

The salinity of the Black and Mediterranean Seas is greatly influenced by the hot climate.

Despite the fact that the Black Sea is located in the Mediterranean basin and is connected to it by the shallow Bosporus, it has a lower salinity. The indicator is lower not only as a result of difficult water exchange with the Atlantic Ocean, but also due to significant amount precipitation and influx of continental waters. In the open part of the sea, this indicator varies from 17.5‰ to 18‰, and in the coastal strip of the North-Western region it is below 9‰.

The salinity of the seas differs from the salinity of ocean waters, which is due to the free exchange of water between the seas and the ocean, water flow and the influence of climate. On the surface of the Mediterranean Sea, water salinity increases from the Strait of Gibraltar to the coasts of Egypt and Syria, and near Gibraltar it reaches 36‰.

Climate

Due to the location of the Mediterranean Sea in the subtropical zone, the Mediterranean climate prevails here: hot summers and mild winters. The January air temperature on the northern coasts of the sea is around +8...+10 °C, and on the southern coast it is +14...+16 °C. The hottest month is August, when Maximum temperature off the east coast it reaches +28...+30 °C. Winds blow over the sea all year round, and in winter cyclones from the Atlantic invade, generating storms.

The sirocco, a sultry wind that carries a lot of dust, breaks through from the African deserts and the temperature often reaches +40°C and above. All these factors affect the salinity of the Mediterranean Sea, increasing its percentage due to water evaporation.

Fauna

The fauna of the Mediterranean Sea is characterized by great species diversity. This is due to the favorable environment and centuries-old history. More than 550 species of fish live here, 70 of which live in a limited range.

Huge schools concentrate here during winter, and in other seasons the individuals stay scattered, especially during spawning or fattening. To achieve this, numerous species of fish migrate to the Black Sea.

The southeastern region of the Mediterranean Sea, influenced by the flow of the Nile River, is one of the most fruitful. The waters of the Nile generously supplied seawater with a large amount of nutrients and mineral suspensions, which affected the salinity of the Mediterranean Sea.

But in the early sixties, the Aswan Hydroelectric Power Station was built, as a result of which the river flow and redistribution of water throughout the year sharply decreased. This significantly worsened the living conditions of marine species, and their numbers decreased. As the desalination zone decreased, useful salts began to flow into the sea in smaller volumes. This led to a significant reduction in the amount of zoo- and phytoplankton; accordingly, the number of fish (sardines, mackerel, horse mackerel, etc.) decreased and fishing was reduced.

Unfortunately, pollution of the Mediterranean Sea is increasing in direct proportion to the development of technological progress, and ecological situation raises concerns among scientists. Let's hope that all caring people will unite and save wealth sea ​​world for posterity.