Water embraces large area our planet. The vast majority of this water is part of the seas and oceans, so it is salty and unpleasant to the taste. According to server "Ocean Service" 3.5% of the oceans are composed of sodium chloride or table salt. That's tons of salt. But where does it come from and, therefore, why is the sea salty?

It's important to know!

For 4 billion years, rain waters the earth, rainwater penetrates the rocks, from where it finds its way to. She carries dissolved salt with her. During geological history the salt content in the sea is gradually increasing. The Baltic Sea, due to low water temperatures, contains 8 times less salt than, for example, the Persian Gulf. If water from all oceans evaporated today, the remaining salt would form a coherent 75 m layer across the world.

Where does the salt in the sea come from?

Yes, some of the salt gets into the water directly from the seabed. At the bottom there are a number of salt-containing stones, from which the salt penetrates into the water. Some of the sodium chloride also comes from volcanic valves. However, according to the BBC, most of the salt comes from the mainland. Therefore, sodium chloride from land is the main reason why the sea is salty.
Each kilogram of sea water contains an average of 35 g of salt. Most of this substance (about 85%) is exactly sodium chloride, known to all kitchen salt. Salts in the seas come from several sources:

• The first source is the weathering of rocks on the mainland; when the stones get wet, salts and other substances that rivers carry to the seas are washed off from them (rocks have exactly the same effect on seabed);
• Another source is the explosions of underwater volcanoes - volcanoes release lava into the water, which reacts with seawater and dissolves some substances in it.

Water also penetrates cracks that lie deep in the ocean floor in areas of the so-called. mid-ocean ridges. Here the stones are hot, often there is lava at the bottom. In the cracks, the water heats up, thereby dissolving a significant amount of salts from the surrounding rocks, which penetrate into the seawater.
Sodium chloride is the most common salt in seawater because it is highly soluble. Other substances dissolve worse, so there are not so many of them in the seas.

Calcium and silicon are special cases. Rivers bring large amounts of these two elements to the oceans, but despite this, they are few in seawater. Calcium is "picked up" by various aquatic animals (corals, gastropods, and bivalve molluscs) and built into their reservoirs or skeletons. Silicon, in turn, is used by microscopic algae to create cell walls.
The sun illuminating the oceans causes large amounts of seawater to evaporate. However, the evaporated water leaves all the salt. This evaporation concentrates the salt in the sea, making the water saline. At the same time, some salt is deposited on the seabed, which maintains the salinity balance of the water - otherwise, the sea would become more salty every year.

The salinity of the water or the salt content of the water varies depending on the location of the water resource. The least salty are the seas and oceans at the north and south poles, where the sun does not shine as much and the water does not evaporate. In addition, the salty water is being diluted by the melting of glaciers.
On the contrary, the sea near the equator evaporates more due to the higher temperatures that prevail in this area. This factor is not only the answer to the question of why the sea is salty, but is also responsible for the increased density of water. This process is typical for some large lakes, which become salty during this process. An example is where the water is so salty and dense that people can lie quietly on its surface.

The above factors are the reasons for the salinity of sea water, as they are understood by scientists at the modern level of scientific knowledge. However, there are several unresolved issues. It is unclear, for example, why different salts are found throughout the world in practically the same proportions, although the salinity of individual seas varies considerably.

Are these hypotheses true?

Of course, no hypothesis is completely correct. Sea water has been forming for a very long time, so scientists do not have reliable evidence about the reasons for its salinity. Why all these hypotheses can be refuted? The water washes away the soil, where there is no such high concentration of salt. In geological epochs, the salinity of water has changed. Salt content also depends on the particular sea.
Water is different for water - salt water has different properties. Sea - characterized by a salinity of about 3.5% (1 kg of sea water contains 35 g of salt). Salt water has different densities and freezing points. The average density of seawater is 1.025 g / ml, it freezes at a temperature of -2 ° C.
The question may sound different. How do we know that the water in the sea is salty? The answer is simple - everyone can easily taste it. Therefore, everyone knows the fact of salinity, but the exact reason for this phenomenon remains a mystery.

Interesting fact! If you visit San Carles de la Rapita and go to the bay, you will see white mountains formed from salt extracted from sea water. If mining and salt water trading are successful, then in the future, hypothetically, the sea risks becoming a "freshwater puddle" ...

Double face of salt

There are huge reserves of salt on Earth that can be extracted from the sea (sea salt) and from mines (rock salt). Kitchen salt (sodium chloride) has been scientifically proven to be a vital substance. Even without precise chemical and medical analyzes and research, it was clear to people from the very beginning that salt is a very valuable, useful and supportive substance that allows them and animals to survive in the world.
On the other hand, excessive salinity causes a decrease in soil fertility. It prevents plants from getting minerals in their roots. Desertification is widespread as a result of excessive soil salinity, for example in Australia.

Often, sailors of ships who were wrecked or lost in sea waters died of thirst. But few people know why this is so, because there is a lot of water around.

The thing is that sea water is saturated with such a composition that it is not suitable for the human body and does not quench thirst. In addition, sea water has a specific taste, bitter-salty and is not suitable for drinking. This is all because of the salts dissolved in it. Let's figure out how they got there.

What gives water a salty taste

The salt is crystalline. Oceanic waters contain almost all elements of the periodic table. Hydrogen and oxygen combine to form water molecules. It also contains impurities of fluorine, iodine, calcium, sulfur and bromine. The mineral base of sea water is dominated by chlorine and sodium (common salt). It is because of this that the sea water is salty. It remains to be seen how the salts get into this water.

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Why was the Black Sea called the Black Sea?

How seawater formed

Scientists have been conducting experiments for a long time and trying to find out why sea water is salty and river water is fresh. There are several theories for the formation of salty seawater.

It turns out that rivers and lakes also have salty water. But the salt content in them is so small that it is almost imperceptible. According to the first theory, river waters entering the seas and oceans evaporate, but salts and minerals remain. Because of this, their concentration increases all the time and the water in the sea and ocean becomes salty.

According to scientists, the process of salinization of the seas has been going on for a billion years. But contrary to the first theory, it has been proven that the waters in the world's oceans have not changed their chemical composition for a long time. And those elements that come with river water only support the oceanic composition, but do not change it in any way. Another theory follows from this. The salt has a crystalline consistency. Waves beating against the shore wash the stones. Holes are formed in them. When the water evaporates, salt crystals remain in these wells. When the stone breaks down, the salt gets back into the water and it becomes salty.

Sea water has a not very pleasant salty and bitter taste, which makes it impossible to drink it. But not every sea has the same salinity. Having visited the beach for the first time, the child often asks the question - what makes the water salty? The question is simple, but it baffles parents. So, why is the water in the seas and oceans salty, what determines the salinity of the water.

Chemical table Mediterranean Sea reaches thirty-nine grams, slightly lagging behind the Red Sea. Oceanic waters are distinguished by a salt content of thirty-four grams.
What is the secret of Red Sea leadership? Above its surface, about one hundred millimeters of precipitation falls on average annually. This is an insignificant amount, given that evaporation reaches up to two thousand millimeters per year.

There is no inflow of water from the rivers flowing into the Red Sea due to the absence of such; replenishment occurs exclusively due to precipitation and water resources of the Gulf of Aden, where the ox is also salty.

Another reason is the mixing of waters. In winter and summer season there is a change of liquid layers. Only the upper layers of water are exposed to evaporation. Salt residues sink to the bottom. For this reason, their number per liter of water is constantly growing.

Sometimes, the Dead Sea is called the saltiest, in which the salt percentage per unit of water reaches more than three hundred grams. This level even affects the fact that fish do not survive in this sea. But the features of this reservoir are such that it has no outlet to the ocean, therefore, it is more logical to consider it a lake.

Everyone who was on the beach could see that the water in the sea tastes salty. But where does the salt come from if the ocean comes fresh water through the rains, rivers and? Why is the sea salty and has it always been so - it's time to figure it out!

How salinity of water is determined

Salinity refers to the salt content of the water. Most often, salinity is measured in “ ppm "(‰). A ppm is one thousandth of a number. Let's give an example: a water salinity of 27 ‰ will mean that one liter of water (this is about 1000 grams) contains 27 grams of salt.

Fresh water is considered to have an average salinity of 0.146 ‰.

Average the salinity of the World Ocean is 35 ‰... Salt water itself is made by sodium chloride, also known as table salt. Among other salts, its proportion in seawater is the highest.

The saltiest sea is the Red Sea. Its salinity is 41 ‰.

Where does the salt in the seas and oceans come from?

Scientists still disagree about whether seawater was originally salty or acquired such properties over time. Depending on the versions, different sources of the appearance of salts in the World Ocean are also considered.

Rains and rivers

Fresh water always has a small amount of salt, and rainwater is no exception. It always contains traces of substances dissolved in it, which were captured during the passage through the atmosphere. Once in the soil, rainwater washes away a small amount of salts and eventually carries them to lakes and seas. From the surface of the latter, water intensively evaporates, falls again in the form of rains and brings new minerals from land. The sea is salty because all the salts remain in it.

The principle is the same with rivers. Each of them is not completely fresh, but contains a small amount of salt trapped on land.

Theory confirmation - salt lakes

The most saline lakes, the Great Salt Lake and the Dead Sea, provide evidence that salt flows through rivers. Both are about 10 times saltier than sea water. Why are these lakes salty while most of the world's lakes aren't?

Lakes are usually temporary storage facilities for water. Rivers and streams bring water to the lakes, and other rivers carry it away from these lakes. That is, from one end, water comes in, from the other - it leaves.

The Great Salt Lake, the Dead Sea and other salt lakes have no outlets. All the water that flows into these lakes leaves only by evaporation. When water evaporates, dissolved salts remain in water bodies. Thus, some lakes are salty because:

• the rivers carried salt to them;
• the water in the lakes evaporated;
• the salt remained.

Over the years, salt in lake water has accumulated to the current level.

Interesting fact: The density of the salt water in the Dead Sea is so high that it practically pushes a person out, not allowing him to go to the bottom.

The same process made the seas salty. Rivers carry dissolved salts into the ocean. Water evaporates from the oceans to rain down again and replenish rivers, but the salts remain in the ocean.

Hydrothermal processes

Rivers and rain are not the only sources of dissolved salts. Not so long ago, on the ocean floor were discovered hydrothermal vents... They represent places where seawater has seeped into rocks. crust, has become hotter and is now flowing back into the ocean. Along with it comes a large amount of dissolved minerals.

Underwater volcanism

Another source of salt in the oceans is underwater volcanism - volcanic eruption under water... It is similar to the previous process in that seawater reacts with hot volcanic products and dissolves some mineral components.

Will the seas be saltier

Most probably not. In fact, the sea has had about the same salt content for hundreds of millions, if not billions of years. The salt content has reached a steady state. The fact is that part of the salts goes to the formation of mineral rocks at the bottom - this compensates for the influx of new salts.

Perhaps not everyone has personally met the ocean, but everyone has seen it at least on school atlases. Everyone would like to go there, right? The oceans are incredibly beautiful, their inhabitants will make you freeze in surprise. But ... many also might have a question: "Salt or fresh water in the ocean?" Still, fresh rivers flow into the oceans. Could this be the reason for the desalination of ocean water? And if the water is still salty, then how did the ocean manage to keep it that way after such an amount of time? So what kind of water in the oceans is fresh or salty? Let's figure it out now.

Why are the oceans salty water?

Many rivers do flow into the oceans, but they bring more than just fresh water. These rivers originate in the mountains and, flowing down, wash out salt from the mountain peaks, and when the river water reaches the ocean, it is already saturated with salt. And given that water in the oceans constantly evaporates, but the salt remains, we can conclude: it will not become fresh from the rivers flowing into the ocean. And now let's delve into the very beginning of the appearance of the World Ocean on Earth, when nature itself began to decide the question of whether there will be salty or fresh water in the oceans. The volcanic gases that were in the atmosphere reacted with water. As a result of such reactions, acids were formed. They, in turn, reacted with metal silicates in the rocks of the ocean floor, resulting in the formation of salts. This is how the oceans became salty.

They also claim that there is still fresh water in the oceans, at the very bottom. But the question arises: "How did it end up at the bottom, if fresh water is lighter than salt water?" That is, it must remain on the surface. During an expedition to the Southern Ocean in 2014, scientists discovered fresh water at the bottom and explained this by the fact that due to the rotation of the Earth, it simply cannot rise up through the denser salt water.

Salt or Fresh Water: Atlantic Ocean

As we have already found out, the water in the oceans is salty. Moreover, the question is "salt or fresh water in the ocean?" generally irrelevant for the Atlantic. The Atlantic Ocean is considered the saltiest, although some scientists are still sure that the most salty ocean- Indian. But it is worth noting that the salinity of water in the oceans fluctuates in different areas. However, in waters it is almost the same everywhere, therefore, in general, salinity does not jump so much.

An interesting fact is that the water in the Atlantic Ocean, as many information networks say, "disappears." There was an assumption that as a result of hurricanes in America, the water was simply carried away by a stream of wind, but the phenomenon of disappearance moved to the coasts of Brazil and Uruguay, where there were no hurricanes. As a result, it was concluded that the water simply evaporates rapidly, but the reasons are still not clear. Scientists are puzzled and seriously alarmed, this phenomenon is being investigated to this day.

Salt or Fresh Water: Pacific Ocean

The Pacific Ocean can, without exaggeration, be called the greatest on our planet. And he became the greatest precisely because of his size. The Pacific Ocean occupies almost 50% of the World Ocean. It is ranked third in salinity among the oceans. Please note that the maximum percentage of salinity The Pacific falls on the zones of the tropics. This is justified by the intensity of water evaporation and is supported by a small amount of precipitation. Going eastward, a decrease in salinity was noted due to cold currents. And if in tropical zones with a low amount of precipitation the water is the most salty, then at the equator and in the zones of western circulation of temperate and subpolar latitudes the opposite is true. Relatively low salinity of the water due to the large amount of precipitation. However, there may well be some fresh water at the bottom of the ocean, just like any other ocean, so the question is "salt or fresh water in the ocean?" in this case it is set incorrectly.

By the way

Ocean waters are not explored as well as we would like, but scientists are trying with all their might to fix it. Every day we learn something new, shocking and mesmerizing about the oceans. The ocean has been explored by about 8%, but has already managed to surprise us. For example, until 2001, giant squids were considered a legend, an invention of fishermen. But now the Internet is just teeming with photographs of huge marine life and this, undoubtedly, makes you wince.

But most of all I want to know after the statement that 99% of all shark species have been destroyed. Sea inhabitants look incredible to us, and we can only imagine what handsome men will never return to our world through the fault of humanity.