Where does salt come from in the seas? Why does the sea taste salty

The sea is salty, but not in the same way as, for example, food prepared by man. It is very salty, even bitter. When a ship with sailors was wrecked, a lot depended on whether the surviving people managed to get fresh water. Without it, they died, because it is impossible to get it from the sea without special water distillers. Some scientists believe that the ocean was established long before life began on Earth. But they are opposed by others. They say that the salt in the seas comes from river water. It only seems that water in the rivers is fresh, it just contains less salt than in sea, about 70 times. But the seas have a huge area, water evaporates from their surfaces, but the salt remains. That's why sea and salty. According to approximate estimates of scientists, approximately 2,834,000 thousand tons of substances enter the rivers every year, which maintain the salt level at the same level. In total, this is no more than one sixteen millionth of all the salt contained in. Considering that rivers supply the amount of matter to sea already quite a long time ago, more than 2 billion years, then this theory is indeed quite probable. Gradually, the substance from the rivers could well salt the seas. True, not all substances are soluble in water. A sufficiently large part of it settles to the bottom and, subjected to enormous pressure of water, connects with the sea landscape. Other scientists believe that water in sea was salty almost from the start. The reason is that during the existence of the primary ocean, the liquid in it is only on? consisted of water, at least 15% of the composition was carbon dioxide, and another 10% were various substances associated with volcanic eruptions. A significant part of what came out of the volcanoes fell in the form of rain, the substances reacted with each other, mixed, resulting in a bitter saline solution. This theory is supported by the different salt composition of the rivers and sea th. Lime compounds and soda predominate in river water, there is a lot of calcium. It contains mainly chlorides, that is, salts formed from of hydrochloric acid, sodium. To this argument, proponents of the theory of gradual salinization of the sea argue that the quality sea water changed various microorganisms and which absorbed calcium and carbonates, while they did not need chlorides. Hence the imbalance in the modern ocean. But this assumption has very few supporters. Most oceanologists adhere to the theory that sea received salt from the rocks, and this happened in a very early planet, and further salinization of the sea did not play into general level salt plays a big role.

Sea or lake?

The Dead Sea is also called a lake, since it does not have access to the ocean. The reservoir is fed only by the Jordan River, as well as several drying streams.

Due to the high concentration of salt in this lake, there are no marine organisms - fish and plants, but different types bacteria and fungi.

Oomycetes are a group of mycelial organisms.

In addition, about seventy species of oomycetes have been found here that can tolerate the salinity of the water to the maximum. More than thirty types of minerals are also common in this sea, which include potassium, sulfur, magnesium, iodine and bromine. Such harmony chemical elements splashes into very interesting formations of salt, which, unfortunately, are not durable.

Red sea

Continuing this theme, it should be noted that the first position, along with Dead, is shared by Red, which is also different high content salt in water.

It is widely believed that water indian ocean and the Red Sea at the junction do not mix, and also differ strikingly in their color.

It is located between Asia and Africa in a tectonic depression, where the depth reaches three hundred meters. Rains in this region are extremely rare, only about a hundred millimeters a year, but evaporation from the sea surface is already two thousand millimeters. This imbalance is the cause of increased salt formation. So, the salt concentration per liter of water is as much as forty-one grams.

It is worth noting that the concentration of salts in this place is constantly growing, since there is not a single body of water in the sea, and the lack of water mass is compensated by the Gulf of Aden.

The uniqueness of these two seas has been known since ancient times and these territories are still very popular among the inhabitants of the planet. After all, the water in these lakes is healing.

Related videos

Cleansing the body with salt water, or the Shankh Prokshalam method is very convenient and practical for cleansing. small intestine, the walls of which can literally become overgrown with all sorts of slags that prevent the intestines from performing their main function of absorbing vitamins and minerals from the food they eat.

Instruction

In the slagged intestine, putrefactive bacteria multiply, which inhibit the growth beneficial bacteria, which leads to the destruction of the intestinal microflora. To prevent the pathologies associated with this, the method of cleansing the intestines with salt water is used.

You can start cleaning only after preliminary preparation. To do this, within a week, you must completely exclude heavy foods (fried, spicy, fatty) from your diet. If possible, take warm baths daily to achieve maximum muscle relaxation, and drink a glass of any freshly squeezed juice in the morning.

Municipal budgetary educational institution

“Lyceum, Arzamas, Nizhny Novgorod Region

Research work for grade 3 "Why is the water in the sea salty?"

Performed:

student 3 "A" class

Ilyina Natalia

Supervisor:

Perepelova

Marina Alekseevna

Arzamas, 2013

Introduction. Target. Tasks.Formulation of the problem.Development of hypotheses.
Chapter 1. Finding a solution and collecting material.

Why is the sea so salty?

Why can't you drink sea water?

Who salted the sea so much?

Chapter 2. Observations and experiments.
Chapter 3. Properties of sea water.

How useful is sea water?

Chapter 4. Salinity of the sea.

What is the salinity of the sea?

How is sea salt extracted?

Chapter 5

Why is the Dead Sea one of the saltiest on Earth?

Is it true that salt purifies the air?

Chapter 6. Conclusions.
Conclusion.

INTRODUCTION

Object of study: salt water of the seas and oceans.
Purpose of the study: Learn the history of the appearance of salt, determine its properties, substantiate the validity of the existence of various hypotheses, conduct your own experiments and observations and find out why the water in the sea is salty?
Research objectives: 1) Read literature and articles on the topic.2) Find out what the salinity of the sea is and how salt is mined.3) Empirically determine the properties of salt.
Methods: Comparison - compare the properties of salt and fresh water.Experiment - conduct experiments.Analysis – analyze the received information.Comparison - compare your hypotheses with the hypotheses of scientists.

Formulation of the problem.

It was this question that interested me when one summer, together with my mom and dad, I was relaxing on the sea. Going to the beach, dad said: “do not forget to take water with you, otherwise you will suddenly want to drink.” How so, I was surprised, because there is a whole sea of water.You can’t drink sea water, my mother said, because it is salty.When we came ashore, the first thing I rushed to the sea, scooped up water with my palm and tasted it. The water was so salty that it even tasted bitter.
The sea was warm and gentle. I sat by the water's edge and thought. Why is sea water salty?

Development of hypotheses.

I have the following assumptions (hypotheses).
1) Suppose that water destroys stones - minerals, thus mineral salts enter the water.
2) Suppose that water from rivers and lakes enters the seas along with particles of various salts accumulated and dissolved in it.
3) Or maybe someone just salted it, like mom salts the broth?

CHAPTER 1.

Finding a solution and collecting material.

What is salt and what does it consist of? When a hungry person sits down at the table, and dinner is not yet ready, he impatiently begins to eat bread and salt. It never occurs to anyone that because of this white crystalline powder lying in an ordinary salt shaker, people could once fight, kill each other, sell into slavery and roam from one country to another. It even happened that a grain of salt could change the fate of a person, and a few grains of this amazing powder returned life to a dying person. And in our days salt fraught with many hidden, surprising and far from known properties. No living organism can live without salt. Salt keeps food from rotting. It lowers the melting temperature of snow and ice. Much is made from salt. essential medicines, and salt is needed for the production of the most ordinary items - soap, glass, fabrics, paper and much more. Therefore, the old Russian proverb “You can’t live without salt” is true even today.
Salt has a crystal lattice.This can be seen if you put a cup of salt water in a warm place. After a while, the water will evaporate, and the salt will fall out at the bottom of the cup in the form of shiny cubic crystals.There is an expression “water wears away a stone”. many, many years picture 1 waves beat against the shore, water droplets, eternal wanderers and eternal workers fall into the same place, a hole forms in the stone, then it collapses. From the destroyed stones - minerals, mineral salts enter the water, and the water becomes salty.
The sea, one might say, is not just salty, it is bitter, unpleasant in taste. After all, it is not for nothing that people in distress on the high seas without a supply of fresh water can die of thirst, because it is impossible to drink sea water.
But why is the sea so salty? Scientists think that in ancient times, millions and millions of years ago, when the waters of the seas accumulated in the vast depressions of the land, they were fresh. Who then salted them so hard?
Yes, all the same droplets of water, eternal wanderers and eternal workers.
The rivers run uncontrollably to the sea. All rivers of the world. They run to it in long winding paths, they flow into the lakes on one side and flow out on the other to continue their run to the sea. To sea! To sea! Why?
Yes, because the level of the seas and oceans is always below the level of land. And the path of water always goes downhill. That is why all rivers flow to the seas, dissolve some rocks and carry away with them particles of different salts. But then an underground stream broke free, ran along the ground, fell into a river and mixed its waters with it, and the waters of these rivers also contain salts, because the river washes them out of the soil.
Why can't you drink sea water?

If we drink sea water, we risk getting not only indigestion, but also dying - due to dehydration of the body: in order to remove excess salt, the body begins to use water from tissue cells, and this leads to dehydration and death. At the same time, compresses, baths, rinses and other procedures using sea water help to cure many diseases: when applied externally, a high concentration of both positive and negative ions gives healing.

Sea water is not suitable for drinking. But in it, many millions of years ago, life originated. The first living organisms appeared in it, which are called microorganisms (“micro”, means small). They grew, changed and became more complex. Many turned into amazing animals and got out on land. And later long years the first people walked the earth. This process is called evolution. And the sea is called the cradle of life.
If the water in the seas and oceans were absolutely clean and fresh (such water is called distilled), then there would be neither animals nor people on earth.
Who could have salted the sea so much? Of course, no one specially salted the sea.But in poems and fairy tales you can find a mention of this. One example is the Norwegian fairy tale “Why is the water in the sea salty”.
One day a sailor stole a magic windmill that could grind anything you wanted. He took her to sea on his ship and demanded that the mill grind salt.When there was enough salt, he ordered the mill to stop, but did not know magic words. Soon there was so much salt that the ship and the mill sank to the bottom of the sea, and the mill continued to grind salt. She continues to grind it until now, that's why the sea is so salty ...It would be nice if the salinity of sea water were explained as simply as in this Norwegian fairy tale.
But scientists still do not have a common opinion why the water in the seas and oceans is salty.

CHAPTER 2

Observation and experiments.

Having studied the material on this topic, I wanted to conduct my own little experiments.I decided to create my own little sea. She poured water into a glass and threw in a pinch of salt. I stirred it like waves in the sea and tried it. What did the water taste like? Where did the salt go? Of course, the salt dissolved and the water became salty.This is a simple confirmation that when minerals enter the water, they dissolve, giving sea water a specific taste.

figure 2

I did another experiment.I took a piece of clay, added some earth and sand to it. Made a small cup out of this. She poured some water into it. Similarly, sea water, like giant bowls, fills huge depressions and depressions in the earth. Then she gently shook the cup, as if the sea was agitated. And I saw that dirt and sand appeared at the bottom of the cup, and the water became cloudy. This water washes away dirt, sand and clay from the walls and from the bottom of the cup. In the same way, various substances enter the sea water from the bottom and shores of the seas.We carry out the third experiment. To do this, I prepared a supersaturated solution. AT warm water dissolved salt in small portions. When the salt ceased to dissolve, the solution was poured into another container and allowed to cool. She dipped a woolen thread into the solution. A day later, the growth of salt deposits was discovered. How interesting, I threw a pinch of fine salt into the water, and got large crystals.A week later the salt grew beautiful crystals cubic shape.The water in the glass evaporated. The walls and bottom of the glass were covered with salt crystals.This happened because the saturated sodium chloride solution moves along the rope to its lowest point due to the capillary effect. The force of gravitycauses the liquid to move along the rope. After the salt solution rises from the glass along the rope, it begins to move down. Due to the capillary effect, the rope pulls brine from a glass.

CHAPTER 3

properties of sea water.

While researching this topic, I wanted to learn a little more about salt water. I began asking everyone about sea water, looking for answers to my questions in magazines and encyclopedias. And here's what I found out.
Which water on earth is more salty or fresh? Salt water is much more. There is little fresh water. Its reserves are found in rivers and lakes.
Which water boils faster, salt water or fresh water? This is easy to find out by putting two identical pots of water on the fire. Salt water in one of them. After a while, we will notice that fresh water will boil faster.

This is because it takes more heat to heat salt water to the boiling point than pure water. Fresh water will boil faster. And now I will put in both saucepans small potatoes. What do I see! Potatoes cook faster in salt water. Just salt water provides more high temperature, so food cooks faster.

Is it possible to get fresh drinking water from salt water?

This can be verified through scientific experience.

Pour some water into a small bowl and dissolve a few tablespoons of salt in it. We put a cup on the bottom, stretch the film on top, and put a pebble on the film, so that we get a small depression, but the film does not touch the cup. Let's put this device in the sun.

The water in the basin will begin to heat up and evaporate. However, the film will delay it, and a clean figure 7 drinking water droplets will settle into the cup. Salt does not evaporate - it remains at the bottom of the basin.

Another one interesting feature associated with the melting of ice from fresh and salt water. I froze cups of fresh water and a salt water solution, then placed them in the same defrosting conditions, and it turned out that the salt ice melted faster. Salt - chemical compound sodium and chlorine, lowers the freezing point of water, preventing its molecules from combining and forming ice crystals.Everyone knows that water freezes at 0, and sea water at -2 degrees Celsius.
I think that everyone has seen - salt is sprinkled on the road in ice and the ice melts even at negative temperatures. Why?

But the fact is that by sprinkling salt on ice, we get a mixture of salt and ice in which the ice begins to melt. This is because the freezing point of this mixture is much lower.

In what water is it easier to learn to swim? Of course, in salty. Salt increases the density of water. The more salt in the water, the more difficult it is to drown in it. In the famous Dead Sea, the water is so salty that a person without any effort can lie on its surface without fear of drowning.Let's do one more experiment.
figure 9

What are the benefits of sea salt? The healing power of the sea has been known since ancient times. Even Hippocrates in the 4th century BC. talked about the healing properties of sea water. Sea water improves skin elasticity, has antiseptic, anti-inflammatory and analgesic properties, relieves stress and increases vitality. It has a beneficial effect on the cardiovascular system, helps with diseases of the musculoskeletal system, radiculitis, polyarthritis, stimulates metabolic processes in the body.

CHAPTER 4

Salinity of the sea.

What elements are included sea salt?

Although scientists have been studying sea water for more than a hundred years, its chemical composition not yet fully explored. However, scientists have been able to identify various chemical substances dissolved in salts. Sea salt contains a huge amount of trace elements necessary for health.

Potassium and sodium are involved in the regulation of nutrition and cell cleansing.

Calcium takes part in blood coagulation, forms cell membranes.

Magnesium is an anti-stress mineral, has an anti-allergic effect, a lack of magnesium accelerates the aging process.

Bromine calms the nervous system.

Iodine regulates hormonal metabolism.

Chlorine is involved in education gastric juice and blood plasma.

Manganese is involved in the formation bone tissue and strengthens the immune system.

Zinc is involved in the formation of immunity.

Iron is involved in the transport of oxygen and the formation of red blood cells.

Selenium prevents cancer.

Copper prevents the development of anemia.

Silicon gives elasticity to blood vessels and strengthens tissues.

What is the salinity of the sea?

Sea water is significantly different from fresh water. If we take and boil water taken, for example, from the Black, Dead and Mediterranean seas, we will see that it boils at different temperatures. The effect of swimming in these seas will cause no less surprise, since the efforts that have to be expended in order to stay afloat are different in all three cases.

In the 70s XVII century Robert Boyle made the first reliable measurements of the total salt content of water taken from different depths of the ocean off the coast of England, after which he suggested the constancy of the salt composition of sea water.

salinity, - conditional value. It reflects the weight in grams of all salts dissolved in a liter of sea water, is measured in tenths of a percent and is denoted by ‰ - ppm.

- river runoff, precipitation, evaporation, formation and melting sea ice;

- vital activity of marine organisms, formation and transformation of bottom sediments;

- respiration of marine organisms, plant photosynthesis, bacterial activity.

It is precisely because of the differences in the salinity of the surface waters of the Black (17–18‰), Mediterranean (36–37‰) and Dead (260–270, and sometimes 310‰) seas that their density also differs significantly and swimming in them requires the expenditure of different efforts. Salt is what leads to the fact that the boiling point of sea water exceeds 100 ° C, and the freezing point is below zero.

How is sea salt extracted? The method of extracting salt from sea water was suggested to man by nature itself. In a dry and hot climate, water evaporates quickly and salt is deposited on the banks and bottom. Observing the process of scaling, a person has learned to arrange accessories for salt mining where climatic conditions allowed to do this, for which they built pools that communicated with the sea and with each other. Today, a network of pools is being created, located near ecologically clean coastal zones. Wooden boards serve as a protection. Under the influence of the sun and wind, the salt evaporates. Then assembled by hand. With this technology, the natural composition of salt is preserved. 95 If all the sea salt is spread evenly over the surface of the land, you get a layer more than 150 meters thick - about a 45-story building!Another comparison can be made: if all the oceans were dried up, then the resulting salt was enough figure 11 on construction of a wall 230 km high. and 2 km thick. Such a wall could circle the entire globe along the equator.But salt layers can also be located underground. And on the surface - in this case, they form salt lakes. These deposits arose over many periods of the life of the Earth. The source of such deposits is sea water, from the salts of which both fossil salt deposits and salt lakes were formed. Thus, salt deposits are the remains of a dried-up ancient ocean.

CHAPTER 5

Where does the salt in the seas come from?

Scientists have discovered several sources of salt.
1. One of them is soil. When rainwater seeps through soil and rocks, it dissolves the smallest particles of minerals, including salts and their chemical elements. Then water currents carry them to the sea. This process is called erosion. Of course, the salt content of fresh water is very low, so it cannot be tasted.
2. Another source is salt-forming minerals in the depths of the earth's crust under the ocean floor. Water seeps through cracks in the crust, gets very hot and is thrown back, saturated with minerals dissolved in it. Deep-sea geysers spew the resulting mixture into the sea.
3. During the reverse process, underwater volcanoes throw huge amounts of hot rock into the ocean, and thus chemical elements enter the water.4. Another source of replenishment of the seas with minerals is the wind, which carries small particles from the land to the sea.Thanks to all these processes, sea water contains almost all known chemical elements. But the most common salt is sodium chloride, or regular table salt. It makes up 85% of all salts dissolved in sea water and is what gives it its salty taste.

Why does the salt composition remain constant?

The salinity of sea water changes with different parts ocean and sometimes depends on the time of year. The highest salinity among open waters is observed in the Red Sea and in the Persian Gulf, where evaporation is very strong. In maritime zones, which receive a lot of precipitation and a huge amount of fresh water from large rivers, salinity is usually below average. Low salinity is also observed in the polar ice melting zones, which are frozen fresh water. On the other hand, when the sea is covered with ice, the water becomes more salty. But in general, the salt composition of sea water remains surprisingly constant.A lot of salt accumulates in the seas, because only pure water. All minerals remain in the sea. Although the sea continues to replenish with minerals, the salt content is always constant - about 35 grams per liter of water.Why is the Dead Sea one of the saltiest? The Dead Sea is located between the Palestinian Authority, Israel and Jordan. It is the third lake in the world after Assal Lake and Kara-Bogaz-Gol Lake in terms of salinity. The rivers flowing into the Dead Sea carry dissolved salts and other minerals. Since the Dead Sea coast is the lowest place on the land surface, the water in this sea is used only for evaporation, which is why in summer its level can drop by 25 millimeters per day. In this regard, the salt content in the upper layers of the water reaches about 30 percent, which is almost ten times higher than in the Mediterranean Sea. Since the density of water increases with increasing salinity, bathers, like floats, float on the surface. And they don't need an air mattress to read a newspaper while lying on their backs.But the saltiest lake on our planet is Lake Assal. Its salinity is 35%.
Lake Assal is located in the central part of Djibouti, in the Danakil Desert. The lake has dimensions of 16x6 km and is located 153 m below sea level. Lake Assal is the lowest point in Africa.Is it true that Withdoes it purify the air?

One study found that air pollution prevents precipitation from clouds over land. However, polluted clouds over the ocean produce rain much faster. This is due to the presence of salt crystals in the air from splashes of sea water.

The water droplets that settle on the polluted particles are too small to become raindrops and therefore remain in the cloud. Sea salt crystals serve as condensation nuclei, attracting the smallest water droplets and forming larger ones. This is how rain falls on the earth, which cleanses the atmosphere of pollution.

CHAPTER 6

Conclusions:

Having studied the material on the topic, and after conducting a series of experiments, I came to the conclusion that my first two hypotheses were fully confirmed, and the third has no scientific justification.I found out that the water in the sea is salty, either because the water destroys the stones, or because all the rivers run to the seas, dissolving some rocks, and carrying away particles of different salts with them.Some scientists believe that rivers brought salt to the sea. Water is the strongest solvent capable of destroying any rock into earth's surface. Rivers carry impurities dissolved by water into the seas and oceans. Water from the ocean evaporates and returns to earth again, continuing its eternal cycle. And the dissolved salts remain in the seas.
Other scientists refute this version, arguing that substances dissolved in sea water were washed out of igneous rocks by flowing waters.Thus, scientists still do not have a single answer to the question: Why is the water in the sea salty?
During the study, the hypotheses put forward were mostly confirmed. Thanks to the research, I learned a lot of new and interesting things. I hope that the knowledge gained will be useful to me at school.

CONCLUSION.

Today there are two main versions of the answer to the question “Why is the water in the sea salty?” One of them is traditional, the other is modern.Traditionally it was thought thatsalty sea water , because rivers bring salt to the sea, washing it out of rocks along which their channel passes. In river water, there is also salt, only it is 70 times less than in sea water. Every year, rivers add one sixteen millionth of the salt of its total volume to the World Ocean.

Sea water constantly evaporates (and the salts remain in the sea!), then returns again in the form of precipitation to land, enters rivers, is again enriched with salt from rocks,

figure 13 which the rivers carry to the sea. It is not surprising that over millions of years of such a water cycle in nature, the World Ocean has pretty much “salted out”. This answer to the questionwhy is the sea water salty , explains and a large number of salt in lakes that do not have a runoff. But he does not explain why the salts in sea and river water have different chemical compositions (and they do!). Therefore, another, more modern hypothesis arose,why is the sea water salty . According to the modern hypothesis, sea water was originally salty, since the primary ocean on Earth is a condensate of gases from volcanic eruptions. The composition of these gases includes water and many chemical elements, among them the so-called "sour fumes", consisting of chlorine, fluorine, bromine and inert gases. Pouring acid rain on the surface of the Earth, the products of volcanic eruptions entered into a chemical reaction with solid rocks, as a result of which a saline solution was formed.

At present, scientists have agreed that both of these hypotheses,

why is the sea water salty , have the right to exist and complement each other.Despite various hypotheses, the appearance of salt in sea water, there is a unified approach to measuring the level of salinity.The salinity of water is the content in grams of all mineral substances dissolved in one kilogram of water.About 35 grams of salt are dissolved in 1 liter of sea water.95

Bibliography.

1. Children's magazine. Stories about the world around for children. The Adventures of a Droplet. Editor Yu.A. Mayorov. No. 8 2010.2. Journal. Planet Earth. No. 3 2008. Article. Salinity of the sea. What it is?Doctor of Geography D.Ya.Fashchuk.3. Journal. World around us. No. 5 2006. Article. Amazing Properties water.V. Golovner, M. Aromshtam.4. Dictionary Russian language / Compiled by M.S. Lapatukhin, E.V. Skorlupovskaya, G.P. Snetova; Ed. F.P. Filin. – M.: Enlightenment, 1997.5. Encyclopedia for the curious. Why and why? Editor T.Frolova. Moscow: Makhaon, 2008.6. Your own observations and experiments.7. Pochemuchka 2009. Cognitive experiments for children.8. Collection. Tales of the peoples of the world. 1988. Norwegian fairy tale. Why is sea water salty?9. Collection of poems. Sea. Verse. Why is sea water salty?10. Magazine. Around the world. No. 7 1999. Article. Why the water in the sea is salty - two hypotheses.11. Magazine. Around the world. No. 3 1997. Article. Salt and fresh water.12. Newspaper. healthy image life. No. 4 2010. Beneficial features salt water.13. Seas and oceans. V.G. Bogorov, St. Petersburg, 1996.

As you know, sea water is a solution various salts giving it a characteristic bitter-salty taste.

At the same time, the rivers that flow into the seas and oceans consist only of fresh water, the concentration of dissolved salts in which is significantly lower than in the sea. But how can this be, why does sea and river water contain such different amount solutes? Let's find out what scientists think about it.

Version number 1 - salt accumulated gradually

Rain or melt water is an almost pure distillate: it contains the minimum amount of substances collected during the fall in the atmosphere to the earth's surface.

Soaking into the soil and collecting in streams, and then in rivers, water dissolves minerals, which are then carried out with river water into the ocean. Evaporation from the surface of the ocean, which is much more intense than on land, again raises pure, distilled water into the atmosphere, and the salts remain in the ocean.

This process has been going on for billions of years, during which the concentration of salts in sea water has increased tenfold. This hypothesis is supported by the existence of salt lakes on the land surface, which have never come into contact with the waters of the oceans. As a rule, these are closed reservoirs into which water only flows in in the form of streams, but does not flow out.

True, this theory does not explain the difference between the composition of salts in sea and river water. Fresh water also contains various salts, but these are usually carbonates - salts of carbonic acid, which are formed as a result of the decay of organic residues - fallen leaves, etc.

The composition of sea water contains up to 80 different chemical elements and their compounds, but the predominant substance in it is sodium chloride, or ordinary table salt, which gives a characteristic salty taste. Where does table salt come from in the sea if it is not washed out from the land? This question is answered by the second version proposed by scientists.

Version number 2 - salt was in the water initially

Billions of years ago, when our planet was still very young, violent volcanic activity took place in its crust. Eruptions large and small were a daily occurrence.

A large amount of volcanic gases were released into the atmosphere and waters of the World Ocean, which contained chlorine, bromine and fluorine in free form. The atoms of these elements reacted with water vapor and formed acid molecules, therefore, in initial period existence of sea water was not salty, but acidic.

These acids, having high chemical activity, reacted with metals contained in volcanic rocks - sodium, magnesium, potassium, etc. The compounds formed as a result of the reaction were the salts that gave the water today's "marine" taste.

The acids were almost completely neutralized, and the modern composition of sea water stabilized about 500 million years ago - a fact proven by studying the rocks of the sea and ocean floor.

But how did it really happen?

Most likely, both processes described above are “to blame” for the fact that sea water has become salty. The water of the World Ocean really received the initial level of salts due to the active volcanic activity of the earth's crust.

Today's salt levels are maintained by the leaching of mineral substances by rivers, as well as by the activity of numerous living organisms that use dissolved substances to build their cells.

An interesting fact: although sea water is completely unsuitable for drinking, the concentration of salt in it corresponds to the content of salts in human blood plasma.

Daily bathing in sea water strengthens the body, helps fight many various diseases skin, respiratory tract, nervous system and etc.

Here's a mystery - why is the sea water salty, but not in rivers and lakes? There is currently no single correct answer to this question, and there are active disputes and discussions on this subject in the scientific world.

Scientists only distinguish two main theories, each of which seems to be true, but at the same time they contradict each other, and there are several strong arguments against each.

First theory. The seas and oceans acquired salinity as a result of slow and gradual processes.

So, according to this theory, sea water became salty as a result of the water cycle in nature. This process can be described in more detail as follows: rain gradually washed out and dissolved mineral salts contained in rocks and soils, rainwater fell into rivers. Rivers also wash out particles of various salts from the bottom, then this one fell into the seas and oceans under the influence of the current. Under the influence of solar heat, water over the seas evaporated and again fell to the ground in the form of rain and other precipitation - the process was repeated. And salt, of course, accumulated in the oceans for millions of years, gradually increasing the level of salinity. But here the big question arises: Why, for more than 500 million years, the salinity level of ocean water has not increased and kept at the same level of 35 ppm (35 grams of salt per 1 liter of water), while rivers have not stopped supplying mineral elements all this time?

Second theory. Ocean water was salty from the beginning.

On the early stages the formation of our planet from the depths of the mantle, along with the first water vapor, volcanic smoke was emitted into the atmosphere. These smokes were enriched with volcanic waste products - chlorine, phosphorus and bromine. Water mixed with these vapors, more like acid than water. The primary acidic water filled the future oceans and seas and destroyed the crystalline rocks of the earth's crust at the bottom, as a result, elements such as potassium, calcium, magnesium, sodium were released ... Then a simple chemical reaction, in which chlorine interacted with sodium, and in fact the salt was obtained. Over time, the activity of volcanoes decreased and the level of salinity of the water stabilized.

Both theories do not give an exact answer, but only suggest a possible course of events and processes. the true reason this interesting question we have yet to find out.

Why is sea water salty and not fresh? There are several theories regarding this. Some researchers claim that salt remains from water from flowing rivers, others that it gets into the water from rocks and stones, and others believe that the reason is volcanic emissions. In addition to salt, sea water contains many various substances and minerals.

Why is there salt water in the sea

Seas are much larger than rivers, but their composition remains virtually unchanged. If all the sea salt is spread on land, we get a layer more than 150 meters thick, which is equal to the height of a 45-story building. Consider several theories why the sea is salty:

The seas become salty from the water of the rivers flowing into them. There is nothing surprising. River water seems quite fresh, but it also contains salt. Its content is 70 times less than in the waters of the oceans. Flowing into the open spaces of the sea, the rivers dilute their composition, but when the river water evaporates, the salt remains at the bottom of the seas. This process took billions of years, so salt accumulated gradually.
The second theory is why there is salt water in the sea. Salts from rivers into the sea settle to the bottom. Over the years, huge boulders and rocks are formed from the salts. Over time, sea currents wash out easily soluble substances and salts from them. Particles washed out of rocks and rocks make sea water salty and bitter.
Another theory suggests that underwater volcanoes can eject into environment many substances and salt. When was it formed Earth's crust, volcanoes were extremely active and emitted acidic substances into the atmosphere. The acids formed rains and formed the seas. At first they were acidic, but then the alkaline elements of the soil reacted with acids and the result was salt. Thus, the water in the seas became salty.

Other researchers associate the salinity of sea waters with winds that bring salt into the water. With soils through which fresh liquid passes and is enriched with salts, and then flows into the ocean. Salt-forming minerals that are part of the ocean floor, which get there from hydrothermal vents, can saturate sea water with salt.

Why is the water in the seas always salty and this composition does not change. Sea water is diluted by rains and flowing rivers, but this does not make it less salty. The fact is that many of the elements that make up sea salt absorb living organisms. Coral polyps, crustaceans and mollusks absorb calcium from salt, as they need it to build shells and skeletons. Diatomaceous algae absorb silicon dioxide. Microorganisms and other bacteria absorb dissolved organic matter. After the organisms die or are ingested by other animals, the minerals and salts in their bodies return to the seabed again as remains or decay residue.

Sea water can be salty and change with the seasons as well as the climate. The highest salinity is observed in the Red Sea and in the Persian Gulf, as it is hot and there is intense evaporation. In marine waters, which receive a lot of precipitation and a large volume of fresh water from large rivers, salinity is much lower. The least saline seas and oceans are near the polar ice, as they melt and dilute the sea with fresh water. But while the sea is covered with a crust of ice, the level of salt in the water rises. But in general, the indicators of salt in the composition of sea water remain constant.

The most salty seas

The first place in salinity is occupied by the unique Red Sea. There are several reasons why this sea is so salty. Due to its location above the sea surface, it falls low level precipitation, and much more water evaporates. Rivers do not flow into this sea, it is replenished due to precipitation and the waters of the Gulf of Aden, which also contain a lot of salt. The water in the Red Sea is constantly churning. Evaporation occurs in the upper layer of water, salts sink to the seabed. Therefore, the salt content is significantly increased. Amazing hot springs were discovered in this reservoirs, the temperature in them is maintained from 30 to 60 degrees. The composition of the water in these sources is unchanged.

Due to the lack of flowing rivers, mud and clay do not get into the Red Sea, so the water here is clean and transparent. The water temperature is 20-25 degrees all year round. Thanks to this, unique and rare species sea animals. Some consider the Dead Sea to be the most salty. Indeed, its water contains a large amount of salt, because of this, fish cannot live in it. But this body of water does not have access to the ocean, so it cannot be called a sea. It would be more correct to consider it a lake.