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 might also have a question: “Salty 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 that it will not become fresh from the rivers flowing into the ocean. And now let's go deep 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's worth noting that the salinity of 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 Atlantic Oceanis, as many information networks say, "disappearing". It was assumed 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 at all. 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 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 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, as in any other ocean, so the question is "salt or fresh water in the ocean?" in this case it was delivered incorrectly.
By the way
Ocean waters are not explored as well as we would like, but scientists are trying their best 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 simply incredible for us, and we can only imagine what handsome men will never return to our world through the fault of humanity.
Everyone who was on the beach could see that the sea water tasted salty. But where does salt come from if fresh water enters the ocean through 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 is confirmed - 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 are not?
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;
- water in 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 seeped into the earth's crust, got hotter and now flows 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.
Water is one of the strongest solvents. It is capable of dissolving and destroying any rock on the earth's surface. Water streams, streams and drops gradually destroy granite and stones, while leaching out of them readily soluble component parts... No solid rock can withstand the ravages of water. This is a long process, but inevitable. 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, but fresh in the rivers?
There are two hypotheses on this score.
First hypothesis
All impurities dissolved in water are carried by streams and rivers to the seas and oceans. River water is also salty, only there are 70 times less salts in it 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 "supply" 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 Kluta River Delta in New Zealand.
Here Kluta is divided into two parts: Matau and Coau,
each of which flows into the Pacific Ocean.
Sea water contains almost all the elements found in nature. It contains magnesium, calcium, sulfur, bromine, iodine, fluorine, and small amounts of copper, nickel, tin, uranium, cobalt, silver and gold. 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 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 (hydrochloric acid salts) prevail in the sea, and carbonates (carbonic acid salts) prevail in rivers.
Second hypothesis
According to this hypothesis, the water in the ocean was initially salty, and the fault is not at all rivers, but volcanoes. Supporters of the second hypothesis believe that during the formation of the earth's crust, when volcanic activity was very high, volcanic gases containing vapors of chlorine, bromine and fluorine were spilled with acid rain. Thus, the first seas on Earth were ... acidic. Entering into chemical reaction with hard rocks (basalt, granite), the acidic water of the oceans extracted alkaline elements from rocks - magnesium, potassium, calcium, sodium. Salts were formed, which neutralized sea \u200b\u200bwater - it became less sour.
As volcanic activity decreased, the atmosphere was cleared of volcanic gases. The composition of ocean water stabilized about 500 million years ago - it became saline.
But where do carbonates disappear from river water, getting into the World Ocean? They are used by living organisms to build shells, skeletons, etc. But they avoid chlorides, which prevail in seawater.
Currently, scientists have agreed that both of these hypotheses have a right to exist, and do not refute, but complement each other.
Sea water has a not very pleasant, salty, 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, a child often asks the question - why is the water salty? The question is simple, but it puzzles parents. So, why is the water in the seas and oceans salty, what determines the salinity of the water.
Impact of the location of seas and oceans
If we take the seas of the planet, then the water in each of them will differ in its composition. Experts say that closer to the northern regions, the salinity index increases. To the south, the percentage of salt in seawater decreases. But here one feature should be remembered - ocean water is always much saltier than sea water, location has no effect on this. And this fact is not explained by anything.
The salinity of water is due to the content of sodium and magnesium chlorides, as well as other salts. Alternatively, certain areas of land are enriched with deposits of these components, thereby distinguishing them from other regions. Quite frankly, this explanation is rather contrived, given the sea currents, because the salt content should stabilize over time throughout the volume.
Reasons affecting the salt content in water
Scientists offer several explanations for the water in the seas and oceans is salty. Some think that the high salt content is possible due to the evaporation of the waters of rivers flowing into the sea. Others argue that salinity is nothing more than the result of water washing away rocks and rocky areas. There are those who compare this phenomenon with the result of the action of volcanoes.
Many are skeptical about the idea that salts enter the seas with river waters. But no one denies that river water still contains salt in itself, however, not in such quantities as in the ocean.
Consequently, a certain desalination occurs from the ingress of river water into the sea, but after the evaporation of river moisture, the salts remain in the sea. Impurities do not create such large volumes, but taking into account the duration of this process, the phenomenon is quite understandable. Salts accumulate at the bottom, being carried further by sea currents and imparting bitterness to the water.
Volcanoes also have an impact. When emitted, they carry a decent amount of various components, including salts. Volcanic activity was especially high during the formation of the Earth. Large emissions of acids were produced into the atmosphere. There is an assumption that the water in the seas was initially acidic from the effects of acid rain. Interacting with calcium, potassium and magnesium, salt accumulations were formed.
There are a number of other reasons that can affect the percentage of salt in water. This reason is associated with winds capable of bringing salts, with a soil composition capable of passing moisture through itself, saturating it with salts, salt-producing minerals located under the ocean floor.
Where is the most salt?
The liquid in the form of seawater is the largest amount on the planet. For this reason, many tend to relax on the sea beaches, going on work vacations. Surprisingly, the mineral composition of the fluids of different seas differs from each other. And there are reasons for this. So which sea is the most salty?
The answer to this question is provided by research statistics. The most salty sea is the Red Sea, which contains forty-one grams of salt in each liter of its liquid. For comparison, a similar amount of water from the Black Sea contains only eighteen grams, the Baltic - only five.
Chemical table Mediterranean Sea reaches thirty-nine grams, somewhat 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 per year reaches up to two thousand millimeters.
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 mixing of waters. In the winter and summer seasons, there is a change of liquid layers. Only the upper layers of water are exposed to evaporation. Residual salts 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.
Why is the sea salty, and where does the salt come from? This is a question that people have been interested in for a long time. There is even a folk tale about this.
As folklore explains
Whose legend it is, 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 brother-rich. 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 it can grind whatever the soul desires. Naturally, the poor man could not live quietly, in abundance, and not talk about his miracle find. In one version, he immediately rebuilt himself a palace on one day, in another - he threw a feast for the whole world. Since everyone around him knew that only yesterday he lived in poverty, those around him began to ask questions, where and why. The poor did not consider it necessary to conceal that he had a magic millstone, and therefore many hunters appeared to steal it. The last such person was a salt dealer. Having stolen the millstone, he did not ask to grind him money, gold, overseas delicacies, because having such a "device", it was already possible not to engage in the salt trade. He asked to grind salt for him so that he would not have to swim for her across the seas and oceans. A miracle millstone was launched, 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 for the fact
Rivers are the main source of salt in the seas and oceans.
Yes, those rivers that are considered fresh (it is more correct to say, 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 famous 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 huge amounts of water together with small admixtures of salts into the depths of the sea. There is evaporation of water, but salts remain. Perhaps earlier, many hundreds of thousands of years ago, the ocean waters were very different. But they add another factor that may explain why the seas and oceans are salty - volcanic eruptions.
Chemicals from volcanoes bringing salt to the sea
In times when earth's crust was in the 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 still taking place, because the seismological activity is much lower than it was millions of years ago, but it is 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 through the movement of precipitation and winds. Moreover, in every open reservoir 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, and the benefits of taking baths, inhalation and the like. It is not for nothing that sea salt is so popular, which is even added to food instead of table salt.
The uniqueness of the mineral composition
We have already mentioned that the mineral composition is unique in each body of water. Why the sea is salty and how much it is, is decided by the intensity of evaporation, that is, the wind temperature in the reservoir, the number of rivers that flow into the reservoir, the richness of flora and fauna. So, everyone knows what kind of sea is the Dead, and why they call it that.
Let's start with the fact that it is incorrect to call this body of water a sea. This lake, as it has no connection with the ocean. He was called dead because of the huge proportion of salts - 340 grams per liter of water. For this reason, no fish can survive in a pond. But as a hospital, the Dead Sea is very, very popular.
Which sea is the saltiest?
But the right to be called the saltiest belongs to the Red Sea.
There are 41 grams of salt in a liter of water. Why is the Red Sea so salty? First, 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 placement in the tropical zone. It would be a little farther south, closer to the equator, and the amount of precipitation typical for this zone would dramatically 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 those 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 now. And this applies to any body of salt water.
The Black Sea is one of the unique compositions
For the same reasons, the Black Sea can be distinguished, whose composition is also peculiar.
Its salt content is 17 ppm, and this is not entirely suitable for marine inhabitants. If the fauna of the Red Sea amazes any visitor with its variety of colors and life forms, then don't expect this from the Black Sea. Most of the "settlers" of the seas do not tolerate water with less than 20 ppm of salts, therefore the diversity of life is somewhat reduced. But it contains many useful substances that contribute to the active development of single and multicellular algae. Why is the Black Sea less salty than the ocean? This is primarily due to the fact that the size of the territory from which river water flows into it exceeds the sea area itself five times. At the same time, the Black Sea is very closed - it is connected with the Mediterranean only by a thin strait, 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 rate, and this, in turn, affects the level and variety of living organisms in it, both flora and fauna. This is a huge system with a lot of parameters that ultimately make up an individual picture.