Salt sea rating. Characteristics of the oceanic aquatic environment

In our country the most salty sea counts Barencevo sea. The surface layers of this sea show salinity from 34.7% to 35%.

White Sea also has a high percentage of salinity: 31% at depth and 26% at the surface.

Kara Sea characterized by high salinity up to 34%. However, in the Kara Sea it is extremely scattered, and in some areas - in the mouths of rivers, for example, the water can be practically fresh.

Chukchi Sea And Laptev sea have a salinity index of 33 and 28 percent, respectively.

Mediterranean Sea is one of the saltiest in the world. The salinity index of this sea is 36-40%. high salinity mediterranean sea limits the development of zoo and phytoplankton. However high salinity does not interfere with representatives of the fauna, which are quite enough in this sea.

Legends and scientific facts about the salinity of the seas

Therefore, the most salty sea on Earth is considered Red sea, which has a salinity index of 41%. The Red Sea not only has extremely high salinity, but also the salinity level is very evenly distributed.

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

1. Dead Sea

Salinity 270‰ The Dead Sea is the saltiest in the world, which is located on the border of Israel and Jordan. The content of minerals is about 270 ‰, and the concentration of salts per 1 liter reaches 200 grams. The composition of the salts of the sea is significantly different from all others. It consists of 50% magnesium chloride, and is also rich in potassium, bromine, calcium and many other mineral elements. Potassium salts are artificially crystallized from its water. Water has the highest density here, which is 1.3-1.4 g / m³, which completely eliminates the possibility of drowning.

In addition to unique salts, the sea contains therapeutic mud, which contains 45% salts. Its characteristics are a high pH value of 9, as well as a bitter and oily taste. The sea temperature can reach 40 degrees above zero, which creates intense evaporation and contributes to high density. If in other waters with high salinity diverse inhabitants live, then in the waters of the Dead Sea they cannot be found.

Red and Dead Sea

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

The World Ocean is a single integral natural body, which occupies 2/3 of the entire area of ​​the globe. Sea water, of which it is composed, is the most common substance on the surface of the Earth. She is different from fresh water bitter-salty taste, specific gravity, transparency and color, more aggressive effect on building materials and other properties. This is due to the content of more than 50 different components in sea water.

Theoretically, all known chemical elements are found in sea water, but their weight content is different.

Of the total amount of dissolved substances, 99.6% are sodium, potassium, magnesium halide salts and magnesium and calcium sulfates, and only 0.4% of the salt composition is accounted for by other substances. It can be seen from the table that only 13 elements of the "Mendeleev's table" are contained in an amount 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, together with calcium, sulfur, carbon and some others, are contained in amounts less than 0.1 mg/l. Sea water also contains organic substances in the form of living matter and in the form of dissolved "inert" organic substances, amounting to a total value of about 2 mg / l.

What determines the salinity of the sea?

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

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

The 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 falls over the sea per year. precipitation, while the amount of evaporation from its surface reaches 2000 mm per year. With the complete absence of river flow, this creates a constant deficit in the water balance of the sea, for which there is only one source to replenish it - the flow of water from the Gulf of Aden. Approximately 1,000 cubic meters of gas is brought into the sea through the Bab el-Mandeb Strait during the year. km of water is more than is taken out of it. At the same time, according to calculations, only 15 years are needed for the complete exchange of the waters of the Red Sea.

In the Red Sea, the water is very well and evenly mixed. In winter, surface waters cool down, become denser and sink down, while warm waters from the depths rise up. 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, the water in the sea is intensively mixed throughout the year, and throughout its volume the sea is the same in temperature and salinity, except in the depressions.

The discovery of hot brine troughs in the Red Sea was real scientific discovery 60s of the twentieth century. To date, more than 20 such depressions have been discovered in the deepest regions. The brine temperature is in the range of 30-60°C and rises 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 underwater vehicles said that the brines do not merge with the surrounding water, but are clearly distinguished from it and look like muddy ground 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 hence the dirt from the land, ensures the fabulous transparency of the water. 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 on the territory of Israel and Jordan. It is located in a tectonic depression formed as a result of the so-called Afro-Asiatic fault, which occurred in an era somewhere between the end of the Tertiary and the beginning of the Quaternary, that is, more than 2 million years ago.

Square Dead Sea 1050 sq. m, depth 356 meters. The only Jordan River flows into it, but it is also fed by numerous mineral springs. The sea has no exit, it is drainless, therefore it is more correct to call it a lake.

The surface of the Dead Sea is 400 meters below sea level (the lowest 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.

For many 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.

Salinity of the Dead Sea

According to the composition of salts, the Dead Sea differs sharply from all other seas of the planet. The salinity of the Dead Sea is 8 times higher than the salinity of the Atlantic Ocean and 40 times Baltic Sea. While in the waters of other seas the content of sodium chloride is 77% of the total salt composition, in the waters of the Dead Sea its share is 25-30%, and magnesium salts account for up to 50%, the content of bromine is 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/cm3. The increase in the density of water with depth, apparently, creates the effect of pushing 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 features of the Dead Sea water include a high pH value of 9.

The Black Sea is inland, its water area is surrounded by land on all sides, only narrow straits lead to the Mediterranean Sea. This entire area belongs to the Atlantic Ocean basin. The salinity of the Black Sea is lower than that of the Mediterranean and Red. The runoff of large rivers desalinates the water area, but its mystery is the formation of a layer of heavier salty water at a depth, the accumulation of dissolved hydrogen sulfide. All this does not interfere with beach and cruise vacations, shipping and fishing. After all, the surface layers are devoid of H 2 S and are well warmed up by the sun.

Cradle of ancient civilizations

The Black Sea is shaped like an oval, elongated in the latitudinal direction. This basin is almost closed, separated by large land masses from other parts of the World Ocean (MO). In the northeast, the Crimean peninsula deeply cuts into the water area, its northeast separates the Black and Azov Seas. The basin is located in the southwestern part of the Eurasian continent. On its surface, from the northeast to the southwest, a border was drawn between two parts of the world - Asia and Europe.

Since ancient times, the life of millions of people has been connected with the waters of the Black and Mediterranean Seas, legends about giants and monsters were born here, the greatest discoveries were made. Suffice it to recall that legends about Scylla and Kharbida, the voyage of the Argonauts led by Jason for the Golden Fleece to Colchis are connected with the straits and the peninsulas and islands surrounding them. Even in ancient times, Greek sailors and merchants highly appreciated the fish riches of this area, created prosperous colony cities on the shores, the remains of which can be seen on the Crimean peninsula. It is difficult to say what the salinity of the Black Sea was in ppm several thousand years ago. This indicator was introduced relatively recently, when a consistent and purposeful study of hydrological features began.

The most important geographical features affecting the salinity of the sea

The narrow straits of the Bosporus and the Dardanelles Black Sea basin connects in series with the Marmara and Aegean seas, leading to the Mediterranean, which, in turn, communicates with the Atlantic Ocean through the Strait of Gibraltar. All of the listed parts of the Moscow Region are navigable and are located in the eastern part of the Atlantic. Physico- geographical features, significantly or moderately affecting the salinity of the Black Sea:

• location in the northern temperate and subtropical climatic zones;
• a large catchment area that determines the flow of fresh water from rivers;
• weak connection with the Atlantic Ocean and the Mediterranean Sea;
• average depth 1240 m, maximum depth 2210 m;
• absence of large tidal waves and low tides.

river runoff

A bunch of European rivers carry their waters from west to east and from north to south. The largest natural channel of the Old World - r. Danube - flows through 10 countries and brings huge fresh masses to the Black Sea. Other large and medium rivers of this basin: Dnieper, Don, Kuban, Bug, Rioni, Dniester.

Fresh river water mixes little with deeper and denser layers, so a significant part of the fresh runoff evaporates from the sea surface. But its volume is so great that it raises the level of the Black Sea water by 5 m relative to the average marks of the Atlantic Ocean. The temperature and salinity of the Black Sea, on the contrary, is lower than in the neighboring parts of the Mediterranean Sea. This feature led to the birth of a current directed to the southwest, towards the Bosporus.

Water mineralization

By studying the salinity of the water of the Black Sea and other parts of the Moscow Region, researchers measure not only general content dissolved substances in different layers and parts of the water area, but also determine elemental composition. In addition to H 2 O molecules, sea water contains gaseous substances, mineral and organic compounds in the form of ions, molecules and other particles. The main components of salts in the Black Sea: carbonates, sulfates, nitrates and chlorides of calcium, magnesium, sodium, potassium. The presence of these dissolved substances is associated with the composition of rocks on land and the seabed. The salinity of the Black Sea is affected by various compounds that come with surface and underground runoff, precipitation. Chemical interactions occur between substances, which also affects the performance.

Water is enriched not only with salts from the composition of dissolved minerals and rocks, there is also organic matter. A significant part of the surface of the Northern Black Sea region is composed of limestones, hence great content calcium, magnesium and sodium salts in water. Basalt rocks, when dissolved, increase the amount of silicon and iron. Substances contained in water increase its overall mineralization. It changes markedly by seasons, from the surface to the depths, from north to south, so reference books, textbooks and atlases may contain different indicators characterizing the salinity of the Black Sea. Most often, average values ​​are given based on long-term data.

What is salinity?

Almost the entire periodic table is present in sea water. But salinity is only the amount of dissolved substances in grams, which are obtained in solid form after evaporating 1 kg of sea water. For convenience, this indicator is expressed as a percentage and ppm.

To facilitate calculations, the content of all halogens is equated to the equivalent amount of molecular chlorine. There are other features, for example, heating is accompanied by the removal of dissolved gaseous substances. When the precipitate is calcined, the organic matter decomposes.

Salinity of the Black Sea in percent

To characterize the indicator under study as a percentage, one must remember the name of the content of a solute in 100 g of a solution. This is a mass fraction, its percentage value can be found by dividing the mass of the solute by the mass of the solution and multiplying by 100%. Suppose, when evaporating 1000 ml of water, a precipitate was obtained, the mass of which is 17 g. The mass fraction (%) of dissolved substances is 1.7%.

Salinity of the Black Sea in ppm

Experimental determination of the mass of dissolved salts in terms of 1 kg of Black Sea water gives different indicators - from 8 to 22 g. To determine the salinity in ppm, let's take the value mentioned more often than others in the literature on the Black Sea - 17 g. The percentage is one hundredth of , and ppm is one thousandth. Divide 17 g by 1000 g and multiply by 1000 (‰). Thus, we get that the average salinity of the Black Sea is 17‰ (ppm). For comparison, we present the average values ​​for the World Ocean - 35‰. The salinity of the Red Sea is 42 ‰, the Kara Sea is 8 ‰. It turns out that the content of dissolved substances in the Black Sea water is almost 2.5 times lower than in the Red Sea.

A simple experiment to determine salinity

There is a way to find out for yourself what mass of substances is contained in sea or fresh water. The experiment is simple, interesting, but for its implementation you will need heat-resistant dishes, a heater and a chemical balance. It should also be taken into account that the density of the saline solution is higher. Therefore, the mass of 1000 ml of sea water is greater than 1000 g. Hence, without taking into account density, the calculations will be approximate.

To find out what the salinity of the Black Sea is, 100-200 ml of sea water will be required. The experience is as follows:

1. Measure the volume and heat the selected liquid in an evaporating cup to a boil.
2. When all the water has evaporated, a white coating will remain at the bottom of the dish.
3. It is necessary to collect the sediment on a piece of paper and weigh it on the scales.
4. The result obtained is the total mass of all dissolved substances in the sample.

How indicators of salinity and water temperature change

The salinity of the Black Sea water in ancient times, as well as in subsequent centuries, was subject to fluctuations under the influence of climatic, meteorological factors, the water regime in coastal regions and economic activity population. The mineralization of water largely depends on the total runoff of large and small rivers. During dry periods, the channels become shallow, less fresh water enters the sea, and the salt content rises.

The main patterns that have developed to date:

• salinity of the surface layers of the Black Sea is 15-18‰, deep - 22.5-22.6‰;
• plumes of low salinity water spread from the northwest along the coast to the south, from the southeast - along the coast of the Caucasus in a northerly direction;
• under the influence of river runoff, the salinity of the surface layer of the sea in the northwest can decrease to 10‰;
• salinity in the Bosphorus region is increased by the incoming water of the Sea of ​​Marmara;
• surface temperature in summer is Black Sea coasts 27-28 C°, in the central part of the water area - up to 22°C;
• maximum salinity surface water- 18.3‰ - located in the east of the central part of the water area, south of Crimea.
• the maximum salinity at a depth of 100 m is located south of the Kerch Strait - over 20.6‰;
• from the surface to 150-200 m the temperature decreases and reaches about 9 °C;
• at a depth of 150 m there is practically no oxygen, hydrogen sulfide appears;
• in winter, the surface of the Black Sea is very cold, in the northern part it can drop to minus levels, but more often it is protected at a level of 8-9 ° С.

During freezing, fluctuations in hydrological parameters are observed. Some parts of the water area are partially covered with ice, and continuous ice cover rarely occurs. For example, chronicles have been preserved about how the Black Sea was covered with such strong ice in winter that merchants on sledges and on foot could reach the Turkish coast.

In general, the conditions of this water area are favorable for the development of flora and fauna. However, scientists have noticed that a decrease in salinity leads to a decrease in the biodiversity of the Black Sea. The fact is that the inhabitants of the World Ocean and its parts do not tolerate salinity below 20‰. For the population of Crimea, desalination of low-salinity sea water in the water area near Sea of ​​Azov is a solution to the problem of drinking and industrial water.

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. Salt gives the water a salty taste, and magnesium - bitter. 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.