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. We are talking 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 The United States of America made the first expedition to explore a 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.

Deep in the ocean are deposits of pure 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 there is salt water in the sea and ocean, 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 occupies most of the Earth's territory. The vast majority of water is in the oceans and seas, and it is salty. According to the Ocean Service, more than 3% sodium chloride (common salt) is found in ocean water.

Why is the water in the seas and oceans salty and where does this salt come from? With the answer to this question, we will try to understand the article.

General information

It happened that the sailors of ships lost in sea waters or wrecked died of thirst, although there was a lot of water around. Few people know that sea water has a composition that is not suitable for the human body. It has a specific bitter-salty taste, which is given by salts dissolved in water.

Rivers flowing into the seas have fresh water, in which the concentration of dissolved salts is much lower than in the sea. But how is this possible, why is the water in the sea salty, and fresh in the river?

For 4 billion years, the continents have been watered by rain. Water, penetrating the rocks, finds its way to the sea. She carries with her dissolved salt into it. In the course of a long geological history, the amount of salt gradually increases. This is one of the simplest hypotheses.

A little about the benefits and harms of salt

Before we find out why the sea is salty and the river is not, let's decide whether salt is useful or harmful. As it turned out, there are huge reserves of salt on Earth, both in the seas (sea) and in the bowels of the earth (stone). Sodium chloride has been scientifically proven to be a vital substance. It has long been known to people that salt is a rather useful and valuable substance that is necessary for both people and animals.

However, there is also a negative side: an excessive amount of salt in the soil leads to a decrease in its fertility. As a result, desertification of territories occurs (for example, in Australia).

Why is the sea water salty

Part of the salt enters the water from the seabed, which contains stones containing salt, from which salt enters the water. Sodium chloride can also come from volcanic valves. But to a greater extent, salts come from the continents. One kilogram of sea water contains, on average, up to 35 grams of salt, and most of it (about 85%) is sodium chloride (kitchen salt known to everyone).

Sources of salt in the sea:

Weathering of rocks: when rocks get wet, substances are washed out of them, and salts are carried away to the seas (a similar effect occurs with rocks on seabed).
Explosions of underwater volcanoes: they release lava into the water, which reacts with sea water and dissolves certain substances in it.

Water has the ability to penetrate into cracks that lie deep in the ocean in the zones of mid-ocean ridges. The stones are hot there (there is often lava at the bottom). Water, heated in cracks, dissolves a large number of salts from underwater rocks that fall into sea water.

Why is sea water salty? Because sodium chloride is the most common salt in it due to the fact that it is it that dissolves best of all substances. However, silicon and calcium are also brought by rivers to the oceans in large quantities. At the same time, there are not so many of them in sea water. This is due to the fact that calcium is “picked up” by various aquatic animals (corals, gastropods and bivalves), and silicon is used by microscopic algae (cell walls are created).

The sun causes the evaporation of a huge amount of water in the seas and oceans. From the evaporated water, salt remains, concentrating in the sea. Therefore, the water becomes salty. It should be noted that some salt is deposited on the seabed. Thanks to this, the balance of salt concentration in the water is maintained, otherwise the sea would become even more salty.

Are the versions correct?

Where does the salt in the sea come from? Which of the hypotheses is the most correct? None of the versions can be ranked as the most correct. The water in the sea and ocean formed over millions of years, so scientists do not have reliable evidence of its salinity. It is known that water washes mainland land which does not contain as much salt. The salinity of water has changed in different geological epochs. And each sea has a different concentration of salt and different properties. The density of water is different, there are differences in freezing points.

It turns out that everyone knows the fact of salinity, but the exact cause of this phenomenon remains a mystery.

Some factors affecting the concentration of salt in water

Answering the question why the water in the sea is salty, one should also find out why the concentration of salt in different seas is different. The salinity of the water varies depending on the location of the natural reservoir. The least saline oceans and seas are located closer to the north and south poles, where the sun does not shine much, and therefore the water does not evaporate. In addition, the water is diluted with the waters of melted glaciers.

The waters of the seas near the equator evaporate more due to elevated temperatures. This factor also affects the increased density of water in these places. Such a process can also occur on some large lakes, which also turn into salty ones. An example is the Dead Sea, where the density and salinity of the water allows people to lie quietly on its surface.

The temperature of the water in the sea also affects the concentration of salt. An example is the Baltic Sea. In connection with low temperatures water, salt it contains 8 times less than, for example, in the Persian Gulf.

Finally

The above hypotheses of the causes of water salinity in the seas and oceans are the opinion of scientists at the current level of knowledge.

One fact is interesting. If water evaporated from all the oceans and seas on Earth today, the remaining salt would form a layer up to 75 meters high all over the world.

Since childhood, we have become accustomed to the fact that the water in the sea, unlike rivers, is salty. Even having never been to the sea, we already knew about it, because our parents and friends told us about it, we read about it in books.

Today, we take this fact for granted, and don’t really think about why the seas and oceans are salty. However, the time has come to consider this issue as part of the articles on our website, so that in the future it will no longer bother you.

Why is the water salty in the seas and oceans

As you know, water has great potential and power. This is most eloquently evidenced by all kinds of natural disasters, which were caused by various tsunamis and hurricanes. Water can easily destroy many things, but it takes time, sometimes even very long.

The same destructive effect of water does not stop before all kinds of mountains, rocks and other natural structures that store many different chemical elements, including those containing salt inside. During the existence of the earth, all kinds of water bodies present in the world's oceans destroyed and dissolved many objects that could saturate the water with salts. However, the question arises as to why the oceans and seas are always salty, while rivers, unlike them, are not.

And here it is necessary to recall such a concept as the water cycle in nature. We remember from the school bench that water is constantly moving through the biosphere of our planet. However, now, using the example of this phenomenon, it is necessary to track the movement of salts, which, according to the most plausible and rational theories, has been going on since ancient times as follows:

Rivers on their way honed stones, rocks, dissolved all possible minerals and other substances, absorbing salt from them.
The water from the rivers flowed along its course to the place where it flowed into the seas.
The seas and oceans were saturated with salt water from the rivers.

Of course, the water cycle also has a further effect - evaporation, which occurs both in rivers and in the seas, as well as in the oceans. However, it is important to understand that in the process of evaporation, water goes into the clouds, and the salt with which it was saturated remains in the seas and oceans. Cyclic repetition this process, which took place for more than one millennium, and led to the fact that today the seas and oceans consist of salt water.

As for the rivers, they continue to destroy all kinds of minerals and carry salt into the oceans, but the salt content in fresh water is so low that it is almost impossible for a person to feel it.

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Why is the sea salty?

Why is the sea salty? - one of the favorite children's summer questions. In our new section "Why" we will regularly answer understandable and plain language for the most interesting questions preschoolers and schoolchildren, as well as hold exclusive contests!

Why is the sea salty? Why does a hedgehog need needles? Why was “-s” added to many words in the last century? Why do cats purr, what do they do? Is it possible to create a time machine according to the laws of physics? You, as a parent or teacher of primary and secondary classes, will hear these questions more than once. We will gladly answer them.

Why is the sea salty?

The answer to this question must begin with an explanation of where the water comes from in the sea and in the ocean. In the rivers we meet keys and springs - underground sources, but where does the water, besides salty, come from in the sea?

The reserves of both the Black Sea and the Atlantic Ocean are replenished with fresh water from rivers and precipitation in the form of snow or rain. Both consist of fresh water (in fact, also salty, just in a very small concentration). But unlike rivers, water from oceans and seas does not flow anywhere, but only evaporates, falling under the sun's rays. When evaporated, the salts remain.

Another factor in the salinity of the sea is the movement of the rivers themselves flowing into it. On the way to the seas and oceans, river flows wash out the salts that make up the stone from the rocks and bring them with them to the sea, albeit in small quantities.

It turns out that the sea has become salty? Was it fresh before? No, it's not. The main reason they agree modern scientists, is the process of formation of the sea itself, which was just as salty millions of years ago. It is not the rivers, which did not exist then, but the volcanoes that covered our planet that are to blame for this.

The water of the primary ocean was formed from volcanic gases, the composition of which is approximately as follows: 75% of the water accounts for 15% of carbon dioxide and about 10% of various chemical compounds. Among these compounds are methane, and ammonia, and sulfur, chlorine and bromine, as well as various gases. So when the products of the eruption hit the ground in the form of acid rain, they reacted with the bottom of the future sea, and as a result we got a saline solution.

How much salt is in the sea?

In one liter of sea water, about 35 grams of salt.

How much water is in the sea?

If we take the average depth of the world's oceans as 3703 meters, and the average surface area is 361.3 million square kilometers, we get 1.338 billion km 3

Which seas are the most fresh and salty?

Let's start with another record holder - the largest sea. The absolute champion in this nomination is the Sargasso Sea, which is located inside the Atlantic Ocean. Its area reaches 8.5 million square kilometers.

But the freshest sea is in Russia, and this sea is the Baltic. Compared to the waters of the Atlantic, its sunshine is 5 times lower. Why? About 250 rivers flow into the Baltic Sea, which "desalinate" the waters.

What about the saltiest sea?

The record holder for the percentage of salts is the Red Sea. Its salinity is about 41 grams per liter of water! This phenomenal content explains the unique properties of the sea: it is very easy to stay on the water, and the very presence is quite good for health.

Why is the Red Sea so salty? The point is evaporation, which we wrote about at the very beginning. Water evaporates from this sea at a great rate due to high temperature and low humidity, so that the rains simply do not have time to “desalinate” it, and besides, they fall very little.

question - contest

Calculate, using the data above, how much TOTAL salt is dissolved in ALL the sea water of our planet?

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Often children ask different questions, to which parents do not always find answers. This situation is familiar to many. It would seem a banal question: why is the water in the ocean salty, confuses adults, and not only them. The opinions of scientists on this issue still differ.

From school curriculum we remember that all rivers flow into the seas and oceans, and, as you know, river water is fresh. But rivers contain small amounts of salt, as does rainwater, so why do the oceans remain so salty?

Several hypotheses have been put forward that are still relevant!

At first, scientists believed that the rivers were not entirely fresh, because for many years they washed out salts and minerals from the earth's rocks, carrying them into sea and ocean waters. And the proof of this hypothesis is the Salt Lake and the Dead Sea, which are 10 times saltier than the oceans. But later, thanks to precise calculations and analyzes, it was found that the rivers could not saturate the oceans with such a large amount of salt.
Perhaps it all began with the primitive ocean, which consisted of a saturated solution of sulfur, methane, chlorine and carbon dioxide. Pure water accounts for only 75%. These data were obtained during the study of basalt deposits and the fossilized remains of various ancient sea creatures that date back billions of years. Such was the initial composition of the super solution, in which the first life began to emerge, in the form of unicellular organisms.
Other hypotheses have been put forward in which volcanoes could have influenced the composition of the water of the ancient ocean. As a result of volcanic activity, a large amount of acidic vapor was released into the atmosphere, which, condensing, spilled onto the earth in the form of acid rain. Over time, the activity of volcanoes decreased, the atmosphere cleared up, and there was less acid rain. Thus, the composition of the water in the oceans returned to normal.
Not so long ago, hydrothermal vents were discovered at the bottom of the oceans. They are formed due to sea water, which, seeping into the earth's rocks, becomes much hotter and is thrown back, bringing with it a large amount of minerals.

It is worth noting that in different seas the percentage of salt is different, that is, each sea and ocean has its own individual composition. For example, the average value of the salt content in sea water is 35g. per 1 liter, but in the Red Sea the salinity reaches 41g. This is due to climatic features. Water in the Red Sea evaporates more intensively, due to high temperature and low humidity. But even under such conditions, this amount of salt remains unchanged and remains constant.

Despite various studies, scientists came to the same conclusion

The salinity of water in the oceans and seas remains at the same level, no matter how much precipitation has fallen and how much fresh river water has arrived. Why is this happening?

Most of the salts are spent on the formation of new mineral rocks, thereby normalizing the composition of water. Salts are involved in the formation of the embryos of marine life.

It is impossible to say which of these hypotheses is correct, because each has confirmation. Which one to believe is everyone's business. Many will prefer the hypothesis of the ancient ocean, someone adheres to the hypothesis of volcanoes and precipitation, and everyone will be right in their own way.

Answering the question of your little "why", you can safely resort to any of the above explanations of the salinity of water in the seas and oceans.