Not only children, but also adults often think about why the water in the ocean and the sea is salty. It must be fresh, because it is replenished by rains, rivers, melting glaciers. When mixing fresh and salty liquid in equal volume, it will remain salty. The same thing happens with the ocean. No matter how much liquid enters it, it still will not become insipid. Everyone needs to know about the salt content, since even in a marine aquarium, water parameters play an important role.
Where is the saltiest water
Since school course Geography, many people remember why the water is salty in the seas and which one comes first. It's about about the Dead Sea, but this is not entirely true. The Dead Sea is 10 times saltier than the ocean average (about 340 grams per 1 liter, a formula is used to calculate the specific gravity of sea water), there are several reasons for this: strong evaporation, rare rains and only one Jordan River flowing into it. In such a liquid, no one can survive, except for a few types of bacteria. It is safe for a person to swim in the Dead Sea or use the mud for healing. Surely everyone knows about an interesting fact: it is impossible to drown in it because of the high concentration of salts. Sea water seems to push the body of a person, no matter how hard he tries to sink to the bottom.
The second place in terms of salinity is occupied by the Red Sea - 41 grams of salt per liter. It was formed approximately 25 million years ago due to the movement of glaciers. Sea water is always warm (even in the winter season), has a rich wildlife.
The Mediterranean completes the top three salty seas. It contains 39.5 grams of salt per liter of liquid, sea water has a boiling point of 100 degrees. It is one of the warmest seas in the World Ocean: in summer the temperature reaches 25 degrees, and in winter - 12. Unlike the Dead Sea, there are enough inhabitants here: sharks, rays, sea turtles, mussels and more than five hundred species of fish. The seas with a high salt concentration include the White, Barents, Chukchi, and Japanese seas. In them, sea waters contain from 30 to 38% salt.
The saltiest place on Earth is Lake Don Juan, located in the northeast of Antarctica. It has a shallow depth (up to 15 cm), sometimes it is compared to a puddle. At the same time, it has such a high concentration of salts that the liquid does not freeze even at an air temperature of -50 degrees. The water in Lake Don Juan is 2 times saltier than the Dead Sea and 18 times the ocean waters.
Don Juan was discovered by chance in 61 of the last century. Helicopters navy United States of America made the first expedition to explore the lake with sea water. One of the pilots was named Donald Rowe, the other was John Hick, and the saltiest body of water "Don Juan" (in Spanish) was named after them.
The Antarctic Dry Valleys are characterized by severe cold and winds. Water appeared from underground, and salt is the result of the evaporation of the upper layers. There are practically no living organisms in it (with the exception of fungi, yeast, algae), in such sea water the microflora has adapted. It is believed that if water is ever found on Mars, it will be the same as in this lake.
Why is ocean water salty
At school, everyone studied geography, in the lessons of which the teacher told why sea water is salty. However, many questions arise. For example, why are precipitation, condensate, rivers, springs, melting glaciers fresh, but the sea does not become less salty? River water is not entirely fresh, as there are salts in the soil. The liquid slowly washes them away, bringing them into the world's oceans. Of course, the person does not notice this at all. Primitive oceans were fresh, and over time they were filled with salty rivers. Research led to other results - the rivers could not salt all the water.
According to the first theory, sea water with a high salt content was the result of massive volcanic eruptions many millions of years ago. They were extremely active and resulted in constant acid rain. The oceans were composed of 10% mixture of methane, chlorine and sulfur, 15% carbon dioxide and 75% water, which is the answer to the question "What substance is found most in sea water?". Numerous acid rains led to reactions, and as a result, this became the cause of the concentrated salt solution.
It is noteworthy that gold can be mined from sea water. A liter of liquid usually contains up to several billionths of a gram of gold. One of the springs is located on the Reykjanes peninsula.
The second theory has already been described above, from which it follows: salt is contained in absolutely every body of water on Earth. Studies show that this is true, but the concentration is negligible for a person to notice. Rivers flowing into the oceans bring washed salts from the soil daily.
Many people believe that the water that evaporates from the surface of the sea or ocean is also salty. However, only moisture is subject to vaporization. A simple experiment can be done at home by leaving an aquarium without fish with sea water near a heat source. After a while, the liquid will evaporate, and the salt will remain.
During the electrolysis of sea water, salt ions accumulate on the corresponding electrodes. Scientists are improving this process by developing safe coatings for the anode.
It cannot be said that either of the two theories is wrong. Both of them are quite logical, but scientists still cannot confirm or refute them.
Can a fresh ocean arise
To answer the question "Can the ocean become fresh?", it is necessary to understand what influences this. The properties of sea waters depend on many factors, only some of them:
- underwater currents;
- evaporation and their activity;
- features of the movement of sea water;
- the presence of glaciers, as well as the rate of melting.
At the depth of the ocean there are deposits of clean fresh water, but not everyone knows that there is gold in sea water. Salt waters cannot become fresh even after many centuries. Scientists are confident that evaporating water does not change salinity. The salt level always remains at the same level. The constancy of the salt composition was discovered by Dietmar, after whom the law is named.
If this does happen (theoretically), it will entail irreversible consequences for the entire planet. First of all, many living organisms will die, because even people use isotonic solutions of sea water. For a long time, fresh liquid will not remain, since salts constantly flow from rivers into ocean waters. However, the latter is just one of several theories as to why sea water is highly saline.
Can the ocean become fresh? Why is sea water salty? These questions are asked not only by curious children, but also by many adults. Everyone knows that in the sea and ocean salty water, but even scientists do not explain why this happens. There are several theories, but which one is correct is still not clear. There is no confirmation whether waters with sea salt can evaporate.
Water is one of the strongest solvents. It is able to dissolve and destroy any rock on the surface of the earth. Water flows, streams and drops gradually destroy granite and stones, while leaching of easily soluble minerals from them occurs. constituent parts. No strong rock can withstand the destructive effects of water. This is a long but inevitable process. The salts that are washed out of the rocks give the sea water a bitter-salty taste.
But why is the water in the sea salty, and fresh in the rivers?
There are two hypotheses for this.
Hypothesis one
All impurities dissolved in water are carried by streams and rivers to the seas and oceans. River water is also salty, only salts in it are 70 times less than in sea water. Water from the oceans evaporates and returns to the earth in the form of precipitation, while dissolved salts remain in the seas and oceans. The process of "delivery" of salts to the seas by rivers has been going on for more than 2 billion years - a time sufficient to "salt" the entire World Ocean.
The Kloota River Delta in New Zealand.
Here Kluta is divided into two parts: Matau and Koau,
each of which flows into the Pacific Ocean.
Sea water contains almost all the elements that exist in nature. It contains magnesium, calcium, sulfur, bromine, iodine, fluorine, copper, nickel, tin, uranium, cobalt, silver and gold are contained in small amounts. Chemists have found about 60 elements in sea water. But most of all, sea water contains sodium chloride, or table salt, which is why it is salty.
This hypothesis is supported by the fact that lakes that do not have a runoff are also salty.
Thus, it turns out that initially the water in the oceans was less salty than it is now.
But this hypothesis does not explain the differences in the chemical composition of sea and river water: chlorides (salts of hydrochloric acid), and in rivers - carbonates (salts of carbonic acid).
Hypothesis two
According to this hypothesis, the water in the ocean was originally salty, and the reason for this was not rivers at all, but volcanoes. Proponents of the second hypothesis believe that during the formation of the earth's crust, when volcanic activity was very high, volcanic gases containing chlorine, bromine and fluorine vapors poured acid rain. Thus, the first seas on Earth were... acidic. Entering into chemical reaction with solid rocks (basalt, granite), the acidic water of the oceans extracted alkaline elements from rocks - magnesium, potassium, calcium, sodium. Salts were formed that neutralized sea water - it became less acidic.
As volcanic activity decreased, the atmosphere was cleared of volcanic gases. The composition of ocean water stabilized about 500 million years ago - it became salty.
But where do carbonates disappear from river water when they enter the World Ocean? They are used by living organisms - to build shells, skeletons, etc. But chlorides, which prevail in sea water, they avoid.
At present, scientists have agreed that both of these hypotheses have the right to exist, and do not refute, but complement each other.
Have you ever thought about this question? And meanwhile he long years provoked heated debate.
If you evaporate a liter of ocean water, then about 35 grams of salt will remain on the walls and at the bottom of the pan.
Is it a lot or a little - a teaspoon about a glass of water? The most incredulous can try ...
If we calculate how much salt is dissolved in the entire World Ocean, the numbers will turn out to be very impressive. It is enough to give such an example: if all the salt extracted from the ocean is spread evenly over the surface of the continents, archipelagos and even islands, then it will cover the land with a layer in which the Leningrad St. Isaac's Cathedral will hide!
But here's what's curious: every year, rivers carry into the oceans about a billion tons of salts and about 400 million tons of silicates, and meanwhile neither the salinity of ocean water, nor its composition change noticeably. What's the matter here?
With silicates, it is more or less clear: they immediately precipitate. And what about salt?.. Apparently, particles of salt with splashes of waves of the smallest dust rise into the air and are picked up by air currents. Tiny crystals rise up and begin to play the role of nuclei for the condensation of atmospheric moisture. Water droplets form around them and form clouds. The wind drives the clouds away from the ocean, and there they rain down, returning the stolen salt to the earth's crust. And her journey with water to the ocean begins again. Here is the cycle...
And yet why is the ocean salty? Was it like this from the very beginning or did it gradually become salty? To answer these questions, scientists had to first solve the problem of the origin of the ocean in general. Did its hydrosphere form together with the Earth or later?
For a long time there was an opinion that the planets were initially in a molten state. It is clear that in this case there was no need to talk about any water on the surface. In this state of affairs, steam must have been rushing over the hot Earth, which from time to time would pour out hot rains and immediately evaporate again and gather into clouds and clouds. Only gradually, as the planet cooled, water from the atmosphere began to linger in the recesses and depressions of the relief. The first seas and oceans appeared. What could they be? Of course, fresh, if they originated from water from the atmosphere, from rain. And only then, after many years, the waters of the World Ocean became salty from the salt carried into the oceans by rivers from the earth's crust. This rather harmonious picture existed for many years.
Today, however, everything has changed. First of all, today most scientists believe that the Earth, like the rest of the planets of the solar system, was formed from a cold gas and dust cloud. Blinded under the influence of gravity forces from huge blocks of ice and iron-stone flying in space. Then, gradually, the substance of this initial planetary coma began to delaminate. The young planet was warming up. The denser, heavier blocks sank deeper, closer to the center, and lighter substances, including water and gases, were pushed to the surface. Gases formed the primary atmosphere, and water formed the hydrosphere. Hot jets under high pressure made their way from the depths upward. On the way, they were saturated with mineral salts. And the water that escaped captivity to the surface of the young Earth probably looked more like a saturated brine, there were so many dissolved minerals in it. chemical elements. And this meant that from the very beginning, from its very birth, the ocean was already salty. It may not be the same as today, but that is still to come.
The idea of a deep, magmatic origin of ocean water was expressed by the Russian and Soviet scientist Vladimir Ivanovich Vernadsky back in the 1930s. Today, his point of view is supported by most experts around the world.
Academician A.P. Vinogradov believes that the ocean "survived" three stages of its development, starting from birth. The first of them fell on the time of the "lifeless" state of our planet. It was four to three billion years ago. There was no biosphere on Earth yet. The world ocean most likely was then small in volume and shallow. Volcanoes threw out from the bowels a lot of solutions, volatile smokes, which contained all kinds of acids. Rains from the sky poured hot and acrid. From such additives, the water in the ocean should have had a pronounced acid reaction.
True, this “acid stage” in the development of the ocean could not continue for a long time. Hot solutions escaping to the surface reacted with salts, bound metals and reduced both their own acidity and that of the primary ocean.
And then at some point in time, about three billion years ago, life began to form in the primordial "broth". At first the most primitive, then more and more complex.
The era of the formation of life lasted extremely long. Living organisms extracted carbon dioxide from the atmosphere and released free oxygen, which at first was practically absent in the primary atmosphere. Oxygen unrecognizably changed everything, even the main property of the atmosphere: it turned from a reducing atmosphere into an oxidizing one. Oxygen oxidized and precipitated, made less mobile such elements as iron and sulfur, calcium and magnesium, which were carried in the smoke of volcanoes above the Earth's surface. They settled and accumulated in the water. Boron and fluorine formed sparingly soluble salts, which also precipitated. The water in the ocean cooled, and silica ceased to dissolve in it. The smallest living organisms learned to use it to build their shells, which, after dying off, went into precipitation ...
Approximately six hundred million years ago, the composition of the water in the oceans and the composition of the atmosphere more or less stabilized. This is confirmed by the remains of extinct animals that paleontologists find in the deep layers of the earth.
I think it should be clear to you: the salinity of water is a very important characteristic of the oceans. And if it suddenly changes in some area, this is a signal: it means that surprises should be expected from Neptune here.
Sea water samples are taken with special devices- bathometers. Projectiles are simple. Ordinary hollow cylinder with two lids that can be easily locked. This process occurs semi-automatically with the help of a weight lowered from above when the bottles reach the required depth. This is done as follows: a garland with bottles tied to a long cable is lowered from the board of a research vessel into the water. At the same time, they make sure that each device paired with a thermometer is on its given horizon. Then you should wait a bit for the thermometers to come into thermal equilibrium with the surrounding water. And when the waiting time expires, a weight is thrown from above along the cable. A split weight with a hole in the middle slides, gets to the first bottle, releases its covers, which snap tightly into place. In addition, at the same time, the thermometers are overturned, fixing the measured temperature, and the second load is released - the second weight. She does the same operation with the second bottle, the third with the third, and so on until the very last device at depth. After that, the entire garland can be pulled up.
But the main thing begins in the laboratory, where the chlorine content of water is determined by rather complex chemical methods, and then it is recalculated for salinity. True, for last years engineers have designed instruments that measure salinity directly from the electrical conductivity of water. After all, the more salt in the water, the less resistance it has. electric current. There is even a special so-called STG probe (STG - salinity, temperature, depth), which shows a continuous depth distribution of all these three most important parameters of ocean water.
Typically, ocean salinity fluctuates between 33 and 38 ppm. (1 ppm is equal to a tenth of a percent. And in order to make a solution with a saturation of 1 ppm, you need to dissolve 1 gram of salt in a liter of fresh water). But there are areas where salinity differs from the norm. There may be exits of underground rivers.
The ocean is the "kitchen of the weather"
What is "weather"? Some take this concept lightly. They say: “The weather? Yes, look out the window - this will be the weather. In fact, weather is the state of the atmosphere in this moment and in this place. If we consider the weather regime on average over many years, then this is the climate. The fact that it is important to be able to predict the weather and know how the climate will change does not need to be said much. This is clear to everyone. Improving methods for forecasting weather and other natural phenomena is an important national economic task. It is clear that the harvest depends on the weather, the construction work carried out by our country depends on the weather, and, finally, people's health depends on the weather.
You have the right to ask: “What does the ocean have to do with it if we live almost in the center of a huge continent?”
To answer this question, I will tell you about one interesting work of scientists.
For quite some time, forecasters have noticed that the average annual temperature in some parts of the North Atlantic fluctuates periodically. Now it rises by 1.5 and even 3 degrees, then it goes down. Experts have given these phenomena the names "warm sea" and "cold sea". At the same time, temperature deviations kept pace with changes in atmospheric pressure. In the case of a “warm sea”, an anticyclone with increased pressure was established over Bermuda, while in the case of a “cold sea”, the pressure decreased in the same area. At the same time, the boundary between the warm Gulf Stream and the cold Labrador Current also changed.
But the most interesting thing was that exactly one month later the situation over Bermuda began to have a very definite effect in Scotland and Scandinavia, after 1.5 months - in Poland, after 2 months the weather changes reached the European part of our country. It turned out, as academician L. M. Brekhovskikh wrote: “If you want to know what the weather will be like in two months in the regions of the European part of the USSR, then carefully study what is happening in the North Atlantic off the coast of Iceland - what are the sea currents there, what is the heat reserve water, air temperature, etc. For an appropriate forecast four months ahead, it is necessary to find out in the same detail what is being done in the Caribbean Sea.
For example, when the “cold sea” regime is established in January, it can be said with sufficient certainty that the February temperature in Switzerland will be three degrees below the norm. And this will certainly lead to an excessive consumption of electricity and fuel. When the “warm sea” regime is established in 2 months, we will also have protracted cyclones with rains and low pressure ...
So far, the mechanism of these connections is not entirely clear to scientists. Comprehensive studies of the ocean and atmosphere are just beginning. Back in the 1970s, meteorologists conceived a big international program GAAP - Global Atmospheric Research Program. For what? To make weather forecasts more accurate. At first, meteorologists wanted to manage on their own and even developed all the points of the program. But very little time passed, and it turned out that they could not do without oceanologists. And only when about 40 research vessels from different countries(including 13 Soviet ones), when aircraft and artificial meteorological satellites of the Earth took an active part in this work, things went smoothly. It may seem strange to some why this ocean is so closely related to the atmosphere. Let's try to figure it out.
Heat balance of the planet
The main energy lever that controls the weather on Earth is heat! And where does our planet get it from? Scientists have calculated that more than 99.9 percent of all the energy that determines the state of the weather and the nature of the climate, as well as that that sets the ocean water in motion, comes from the Sun. Of course, some heat seeps from the bowels of the earth. But its share is very small. The energy received from space drives countless parts of the huge "heat engine" that is the Earth. And after use, it returns to space.
It would seem that we can conclude: Sun rays, passing through the atmosphere, heat it, and give the rest of their heat to the ocean and land. But it's not right. Of all the energy that the atmosphere has, only 20 percent comes directly from heating by the sun's rays. Most of the rest of the energy is added to the atmosphere by the ocean. He, like a huge battery, stores it during the day, in hot summers, and releases it at night, softening cold winters not only in coastal areas, but also in the depths of continents.
How does the ocean regulate the heat balance of the planet? You know from the laws of physics that it takes 600 calories of heat to evaporate 1 gram of sea water. Water vapor condenses and collects into clouds. The winds drive the clouds to the high latitudes, where they rain down. The same physicists calculated that when steam condenses and 1 gram of moisture falls as rain, about 540 calories of heat are released. Well, compare ... It turns out that the lion's share of the energy stored in the tropics is transferred through the atmosphere to the poles with the help of evaporation alone. After all, an average layer of water more than a meter thick evaporates from the surface of the oceans per year. Those who love mathematics can also calculate the total number of calories of transferred heat. And then there are the currents...
In order to clearly imagine the interaction of the ocean with the atmosphere, scientists - oceanologists and meteorologists - must collect a lot of data. But at the same time, it must be borne in mind that the ocean lives, moves, and all its parameters are constantly changing. And there is nothing to say about the mobility of the atmosphere.
In the Soviet Union, under the leadership of Academician G. I. Marchuk, a method of mathematical models of the circulation of the atmosphere and ocean was developed. What is a "mathematical model"? In principle, this is a system of equations that describe certain interrelated processes in complex systems. For oceanologists, such a system is the ocean, for meteorologists it is the Earth's atmosphere, the ocean of air. Solve these equations with the help of electronic computers.
Mathematical models are an extremely successful invention of the human mind. With their help, on paper, you can create analogues of a variety of conditions. Thinking, suppose people block dams sea straits. And ocean currents follow them. What will the planned event turn out for the whole Earth? And this question can be answered mathematical models. There are problems for mathematicians local importance, but there are also global ones. Here is a relatively recent problem, for example. The developing industry every year increases the amount of carbon dioxide that is emitted into the atmosphere. It would seem that nothing special: carbon dioxide is a transparent substance, it does not delay the sun's rays; in addition, it serves to nourish plants ... But it turns out that carbon dioxide has an insidious property: it passes light rays, but it delays heat rays. It turns out that solar radiation to the surface of the Earth passes unhindered, and the heat from the heated water and land does not go back into space. How greenhouse glass covers our planet with carbon dioxide. This means that the surface temperature also increases.
You might be thinking, “Well, what’s wrong with that? Let there be more heat, they will grow in Moscow, Leningrad, or maybe even in Murmansk palm trees will grow ... ”In fact, warming will turn into innumerable troubles for us. The ice and eternal snows will begin to melt. Additional water will pour into the world's oceans, raise its level, flood coastal cities. If the polar ice caps melted, the level of the world's oceans would rise by about 60 meters!
But is such a global catastrophe possible? To accurately answer this question, you need to make mathematical models very carefully. To take into account in them not only the current achievements of science, but also to program forecasts for the future. So far, we can only say that the heat balance of our planet is not very stable. Traces of past epochs show that the climate of the Earth in the past experienced very significant fluctuations. During the existence of man, there have been several such fluctuations. Scientists call them cycles of glaciation. During each such cycle, the Earth passed from the state of interglacial to the state of glaciation and vice versa. Unfortunately, the glacial phases each time lasted much longer than the interglacials.
During periods of glaciation, mountain glaciers sea ice and the ice sheets grew considerably in size. Water was frozen out of the ocean, and its level dropped. For example, during the last great glaciation, the maximum of which was only eighteen thousand years ago, the level of the World Ocean dropped by more than 100 meters, exposing most of the shelf.
But not only great ice ages threaten the Earth. They are still quite rare. But even during interglacial periods, there are so-called small ice ages on our planet. So, having collected a lot of ship observations and carefully selecting all references to the weather of past years from ancient annals and chronicles, scientists found that from about 1450 to 1850, winters on Earth were much more severe than in our time. The summers were shorter and not as hot, and the mountain glaciers descended well below their current limits. Sailors noted that the ice edge in the Atlantic passed much further south.
Why? What is the reason for such a cataclysm? Science cannot yet answer this question. Imagine how much work remains to be done in this area!
How many discoveries await future oceanologists and meteorologists! The prospects for them are truly remarkable.
Where is born "tai fyn" - "big wind" and where is "khurakan" - "heart of the sky" and "heart of the earth"
Of particular interest to all people is the question of how changing conditions in the ocean affect the occurrence of terrible tropical cyclones, which are called hurricanes in the Atlantic, and typhoons in the Indian and Pacific oceans.
Today, thanks to the space service of meteorological satellites and direct observations of astronauts, the areas of origin of tropical cyclones are well known. There are not very many of them: in the Atlantic it is mainly the Caribbean Sea and the Gulf of Mexico; in the Indian and Pacific Oceans, autumn typhoons originate in the southern and southwestern regions.
In addition, their centers are the Philippine Islands and the South China Sea. But typhoons that hit the east coast of Asia and India all year round originate in the western part of Pacific Ocean and in the northern regions of the Indian.
A tropical cyclone is a system of very strong winds that blow and swirl around a windless center of low pressure called the eye of the cyclone. Interestingly, in the Northern Hemisphere, the wind spins around the "eye of the cyclone" always counterclockwise, and in southern hemisphere- in her course. A cyclone can capture an area of up to 1,000 square kilometers, while its windless "eye" will only have a diameter of some 20-40 kilometers. The wind on the periphery of the cyclone can pick up speed up to 300 kilometers per hour.
Tropical cyclones cause enormous damage both at sea and on land in coastal areas. They generate giant waves and sink ships. Water breaks into the flat coast, destroys shallows, causes terrible floods and destroys people's homes.
In September 1900 in North America, in Texas, about 6 thousand people died during the hurricane. In September 1928, a tropical cyclone swept over the state of Florida, claiming about 2,000 lives. And ten years later, about the same hurricane killed 600 New Englanders. The enumeration of the sad consequences could go on and on. But you have probably already noticed that the closer to our days, the lower the number of victims. This is because weather forecasters have already learned to warn of a formidable phenomenon at least a day in advance.
Moving over land or over water expanses with more cold surface than in the places of their birth, hurricanes lose strength. So it is the evaporation warm water energizes them. And I must say, it feeds well. The total energy of a tropical cyclone is roughly the energy of hundreds of 20-megaton bombs detonating simultaneously! It is comparable to the entire amount of electricity that our country's power plants generate over a five-year period.
Traditionally, tropical cyclones are given female names. Previously, they were called the names of those saints on whose feast day they appeared. In addition, they were also assigned a number. It got pretty cumbersome. During the Second World War, when information about an approaching storm had to be transmitted by radio, preferably as quickly as possible, letters of the Latin alphabet began to be assigned to tropical cyclones. And in order to transmit a letter without error, radio operators used the appropriate woman's name starting with this letter. And so the tradition was born. However, since 1979, the US weather service has added male names to the list of cyclones.
"Huracan" in the language of the Indians of Guatemala means "one-legged." So they called it fast, like the wind, the creator and ruler of the world, the lord of thunderstorms, winds and hurricanes. The most common epithets of this terrible deity were "the heart of heaven" and "the heart of the earth."
But the word "typhoon" comes from the Chinese words "tai feng" - "big wind". And you can judge how true this is.
Why is ocean water salty and fresh water in rivers? The answer to this question is ambiguous. There are different points of view that reveal the essence of the problem. According to scientists, it all comes down to the ability of water to break down rock and leach easily soluble components out of it, which end up in the ocean. This process is ongoing. Salts saturate sea water, giving it a bitter-salty taste.
Everything seems to be clear, but at the same time, there are two diametrically opposed opinions on this issue. The first boils down to the fact that all the salts dissolved in water are carried by rivers into the ocean, saturating sea water. There are 70 times less salts in river water, therefore it is impossible to determine their presence in it without special analyzes. We think that river water is fresh. In fact, this is not entirely true. Saturation of sea water with salts occurs constantly. This is facilitated by the evaporation process, as a result of which the amount of salts is constantly increasing. This process is endless, and lasts about two billion years. There is enough time to make the water salty.
The composition of sea water is quite complex. It contains almost the entire periodic table. But most of all, it contains sodium chloride, which makes it salty. By the way, in closed lakes the water is also salty, which confirms the correctness of this hypothesis.
Everything seems to be correct, but there is one but! Sea water contains salts of hydrochloric acid, and river water contains coal. That is why scientists put forward an alternative hypothesis. They believe that sea water was originally salty, and rivers have nothing to do with it. This is due to volcanic activity, the peak of which occurred at the time of the formation of the earth's crust. Volcanoes emitted huge amounts of steam saturated with acids into the atmosphere, which condensed and fell to the ground in the form of acid rain. Sediments saturated seawater with acid, which reacted with solid basaltic rocks. As a result, a huge amount of alkali was released, including sodium, potassium and calcium. The salt thus obtained neutralized the acid in the sea water.
Over time, volcanic activity decreased, the atmosphere was cleared of vapors, and less and less acid rain fell. About 500 million years ago, the composition of sea water stabilized and became what we know it today. But the carbonates that enter the ocean with river water serve as an ideal building material for marine organisms. They build coral islands, shells, their skeletons out of it.
Which hypothesis to prefer is a purely personal matter. In our opinion, they both have a right to exist.
Why is the sea salty and where does the salt come from? This is a question that has interested people for a long time. There is even a folk tale about this.
As folklore explains
Whose legend is this, and who exactly invented it, is no longer known. But among the peoples of Norway and the Philippines, it is very similar, and the essence of the question of why the sea is salty, the tale conveys as follows.
There were two brothers - one rich, and the other, as usual, poor. And no, to go and earn bread for his family - the poor goes for alms to the stingy rich brother. Having received a half-dried ham as a “gift”, the poor, in the course of some events, falls into the hands of evil spirits and exchanges this very ham for a stone millstone, modestly standing outside the door. And the millstone is not simple, but magical, and can grind everything that the soul pleases. Naturally, the poor man could not live quietly, in abundance, and not talk about his miracle find. In one version, he immediately built a palace for himself one day, in another, he threw a feast for the whole world. Since everyone around him knew that just yesterday he lived in poverty, those around him began to ask questions about where and why. The poor man did not consider it necessary to hide the fact that he had a magic millstone, and therefore many hunters appeared to steal it. The last such person was a salt merchant. Having stolen the millstone, he did not ask him to grind money, gold, overseas delicacies, because having such a “device”, one could no longer engage in the salt trade. He asked to grind salt for him so that he would not have to swim behind her across the seas and oceans. A miracle millstone started up, and it ground so much salt for it that it sank the ship of the unfortunate merchant, and the millstone fell to the bottom of the sea, continuing to grind salt. This is how people explained why the sea is salty.
Scientific explanations of the fact
Rivers are the main source of salts in the seas and oceans.
Yes, those rivers that are considered fresh (more correctly, less salty, because only distillate is fresh, that is, devoid of salt impurities), in which the salt value does not exceed one ppm, make the seas salty. This explanation can be found in Edmund Halley, a man known for the comet named after him. In addition to space, he studied more mundane issues, and it was he who first put forward this theory. Rivers constantly bring a huge amount of water, along with small impurities of salts, into the depths of the sea. There, water evaporates, but salts remain. Perhaps earlier, many hundreds of thousands of years ago, the ocean waters were very different. But they add another factor that can explain why the seas and oceans are salty - volcanic eruptions.
Chemicals from volcanoes that bring salt to the sea
At times when Earth's crust was in a stage of constant formation, There were frequent ejections of magma with an incredible amount of various elements to the surface - both on land and under water. Gases, indispensable companions of eruptions, mixing with moisture, turned into acids. And those, in turn, reacted with the alkali of the soil, forming salts.
This process is happening now, because seismological activity is much lower than it was millions of years ago, but still present.
In principle, the rest of the facts explaining why the water in the sea is salty have already been studied: salts enter the seas from the soil by means of movement by precipitation and winds. And in every open body of water chemical composition the main earth fluid is individual. When asked why the sea is salty, Wikipedia answers in the same way, only emphasizing the harm of sea water for the human body as drinking water, and the benefits when taking baths, inhaling and the like. No wonder it's so popular sea salt, which is even added to food instead of cooking.
The uniqueness of the mineral composition
We have already mentioned that mineral composition unique in every body of water. Why the sea is salty and how much it is, decides the intensity of evaporation, that is, the temperature of the wind on the reservoir, the number of rivers that flow into the reservoir, the richness of flora and fauna. So, everyone knows what the Dead Sea is, and why it is called that.
Let's start with the fact that it is incorrect to call this body of water a sea. It is a lake because it has no connection with the ocean. They called him dead because of the huge proportion of salts - 340 grams per liter of water. For this reason, no fish is able to survive in the reservoir. But as a hospital, the Dead Sea is very, very popular.
Which sea is still the most salty?
But the right to be called the most salty belongs to the Red Sea.
There are 41 grams of salts in a liter of water. Why is the Red Sea so salty? Firstly, its waters are replenished only by precipitation and the Gulf of Aden. The second is also salty. Secondly, the evaporation of water here is twenty times higher than its replenishment, which is facilitated by the location in the tropical zone. If it were a little further south, closer to the equator, and the amount of precipitation typical for this zone would drastically change its content. Due to its location (and the Red Sea is located between Africa and the Arabian Peninsula), it is also the warmest sea among all available on planet Earth. Its average temperature is 34 degrees Celsius. The whole system of possible climatic and geographical factors made the sea what it is today. And this applies to any body of salt water.
The Black Sea is one of the unique compositions
For the same reasons, one can single out the Black Sea, whose composition is also peculiar.
Its salt content is 17 ppm, and these are not quite suitable indicators for marine inhabitants. If the fauna of the Red Sea strikes any visitor with its variety of colors and forms of life, then do not expect this from the Black Sea. Most of the "settlers" of the seas do not tolerate water with less than 20 ppm salts, therefore the diversity of life is somewhat reduced. But it contains many useful substances that contribute to the active development of unicellular and multicellular algae. Why is the Black Sea half as salty as the ocean? This is primarily due to the fact that the size of the territory from which river water flows into it exceeds the area of the sea itself by five times. At the same time, the Black Sea is very closed - only a thin strait connects it with the Mediterranean, but otherwise it is surrounded by land. Salt concentration cannot become very high due to intensive desalination by river waters - the first and most important factor.
Conclusion: we see a complex system
So why is the sea water salty? It depends on many factors - river waters and their saturation with substances, winds, volcanoes, precipitation, evaporation intensity, and this, in turn, affects the level and diversity of living organisms in it, both flora and fauna. This is a huge system with a large number of parameters that ultimately make up an individual picture.