Having visited the beach for the first time, the child asks his parents: why is the water in the sea salty? This simple question baffles adults. After all, everyone knows that a bitter aftertaste will definitely remain on the lips and the whole body. Why is the sea salty? We begin to reason: fresh rivers flow into this part of the World Ocean. So it can't taste that bad! But you can’t go against the facts: the water is not fresh. Let's figure out at what stage the initial composition of H2O changes.
Why is the salinity increased?
There are several theories about this. Some scientists believe that salt remains from the evaporated water of flowing rivers, others - that it is washed out of rocks and stones, others associate this compositional feature with the action of volcanoes... Let's begin to consider each version in order:
The reservoir becomes salty from the water of the rivers that flow into it. Strange pattern? Not at all! Although river moisture is considered fresh, it still contains salt. Its content is very small: seventy times less than in the vast depths of the World Ocean. Therefore, flowing into a large body of water, rivers desalinate its composition. But the river water gradually evaporates, but the salt remains. The volumes of impurities in the river are small, but over billions of years a lot of them accumulate in sea water.
Salts flowing from rivers into the sea settle on its bottom. From them, huge blocks of stone and rocks are formed on the ocean floor over thousands of years. Year after year, the current destroys any stones, leaching easily soluble constituent substances from them. Including salt. Of course, this process is long, but inevitable. Particles washed out of rocks and rocks give the ocean an unpleasant, bitter taste.
Underwater volcanoes eject into environment many substances, including salts. During education earth's crust Volcanic activity was very high. They released acidic substances into the atmosphere. Frequent acid rain formed seas. Accordingly, first the water in components the ocean was acidic. But the alkaline elements of the soil - potassium, magnesium, calcium, etc. - reacted with acids and formed salts. Thus, water in various places of the ocean acquired the characteristics that are now familiar.
Other assumptions known today are related
- with the winds bringing salt into the water;
- with soils, passing through which fresh liquid is enriched with salts and enters the ocean;
- with salt-forming minerals located under the ocean floor and supplied through hydrothermal vents.
It is probably correct to combine all the hypotheses in order to understand the ongoing process. Nature gradually built all its ecosystems, closely intertwining things that were incompatible at first glance.
Where is the highest concentration of salt?
Sea water is the liquid that is most abundant on earth. It’s not for nothing that many people associate vacations primarily with the beach and coastal waves. Surprisingly mineral composition The liquids in different bodies of water are never the same. There are many reasons for this. For example, salinity depends on the intensity of fresh water evaporation, the number of rivers, types of inhabitants and other factors. Which sea is the saltiest?
The answer is given by statistics: the Red Sea is rightfully called the saltiest. One liter of its water contains 41 grams of salts. If we compare with other reservoirs, then in a liter of liquid from the Black there are 18 grams of various salts, in the Baltic this figure is even lower - 5 grams. IN chemical composition Mediterranean - 39 grams, which is still lower than the above characteristics of Red. In ocean water - 34 grams.
Reasons for the unique feature of the Red Sea:
On average, about 100 mm of precipitation falls above the surface per year. This is very little, considering that about 2000 mm of water evaporates per year.
No rivers flow into this reservoir; it is replenished only by precipitation and waters from the Gulf of Aden. And its water is also salty.
The reason is also the intensive mixing of water. In winter and summer, the layers of liquid change. Evaporation occurs in top layer water. The remaining salts fall down. Therefore, the salinity of water in this part of the water expanse increases significantly.
The Dead Sea is sometimes called the saltiest. Its waters contain 340 grams of salt per liter of water. That’s why it’s dead: the fish die in it. But some features of this body of water do not allow it to be considered a sea: it does not have access to the ocean. Therefore, it is more correct to call this body of water a lake.
Sea water has a not very pleasant salty and bitter taste, which makes it impossible to drink. But not every sea has the same salinity. When visiting the beach for the first time, a child often asks the question: why is the water salty? The question is simple, but it baffles parents. So, why is the water in the seas and oceans salty, what does the salinity of the water depend on.
Impact of the location of seas and oceans
If we take the planet’s seas, the water in each of them will differ in its composition. Experts say that closer to the northern regions, the salinity indicator increases. To the south, the percentage of salt content in sea water decreases. But here one thing should be remembered - ocean water is always much saltier than sea water, location does not affect this. And this fact cannot be 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 in deposits of these components, thereby differing from other regions. Frankly, this explanation is quite far-fetched, given sea currents, since salt levels should stabilize throughout the volume over time.
Reasons affecting the salt content in water
Scientists offer several explanations for the fact that the water in the seas and oceans is salty. Some people think that the high salt content is possible due to the evaporation of water from rivers flowing into the seas. Others argue that the salinity is nothing more than the result of water washing away stones 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, although not in such quantities as in the ocean.
Therefore, from falling into the sea river water a certain desalination occurs, 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 giving the water bitterness.
Volcanoes also have their effect. When released, they carry a decent amount of various components, including salts. Volcanic activity was especially high during the formation of the Earth. Large amounts of acid were released into the atmosphere. There is an assumption that due to the effects of acid rain, the water in the seas was initially acidic. Interacting with calcium, potassium and magnesium, salt accumulations were formed.
There are a number of other reasons that can affect the percentage of salt content 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-releasing minerals located under the ocean floor.
Where is the most salt found?
Liquid in the form of sea water is greatest number on the planet. For this reason, many people seek to relax on the sea beaches when going on vacation. Surprisingly, the mineral composition of liquids from different seas differs from each other. And there are reasons for this. So, which sea is the saltiest?
The answer to this question is provided by research statistics. The most salty sea is rightfully Red, containing forty-one grams of salts 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.
The chemical table of the Mediterranean Sea reaches thirty-nine grams, slightly behind the Red Sea. Ocean waters have a salt content of thirty-four grams.
What is the secret of Red Sea leadership? On average, about one hundred millimeters of precipitation falls above its surface every year. Is not significant amount with the indicator that evaporation per year reaches up to two thousand millimeters.
There is no influx of water into the Red Sea from the flowing rivers due to the lack of such; replenishment occurs exclusively due to precipitation and water resources of the Gulf of Aden, where the water is also salty.
Another reason is the mixing of waters. In winter and summer season There is a change in liquid layers. Only the upper layers of water undergo evaporation. The remaining 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 cannot survive in this sea. But the features of this reservoir are such that it does not have access to the ocean, therefore, it is more logical to consider it a lake.
Water covers a large area of 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 the server "Ocean Service" 3.5% of the oceans are made up of sodium chloride or table salt. This is tons of salt. But where does it come from and, therefore, why is the sea salty?
It is important to know!
For 4 billion years, rain has been watering the earth, rainwater penetrates into the rocks, from where it finds its way into. It carries dissolved salt with it. Over the course of geological history, the salt content of the sea gradually increases. Baltic Sea, due to low temperatures water, contains 8 times less salt than, for example, the Persian Gulf. If the water from all the oceans evaporated today, the remaining salt would form a coherent layer 75 m high around the world.
Where does the salt in the sea come from?
Yes, some of the salt enters the water directly from the seabed. At the bottom there is a whole series of salt-containing stones, from which 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 on average 35 g of salt. Most of this substance (about 85%) is sodium chloride, the well-known 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, they wash away salts and other substances that rivers carry into the seas (rocks on the seabed have exactly the same effect);
- Another source is explosions of underwater volcanoes - volcanoes release lava into the water, which reacts with sea water and dissolves some substances in it.
Water also penetrates into cracks that lie deep on the ocean floor in areas called mid-ocean ridges. The rocks here are hot and there is often lava at the bottom. In the cracks, the water heats up, due to which it dissolves a significant amount of salts from the surrounding rocks, which penetrate into the sea water.
Sodium chloride is the most common salt in seawater because it is the most soluble. Other substances dissolve less well, so there are not so many of them in the seas.
Special cases are calcium and silicon. Rivers bring large amounts of these two elements into the oceans, but despite this, they are scarce in seawater. Calcium is “picked up” by various aquatic animals (corals, gastropods and bivalves) and built into their tanks or skeletons. Silicon, in turn, is used by microscopic algae to create cell walls.
The sun shining on the oceans causes evaporation large quantity sea water. However, the evaporated water leaves all the salt behind. This evaporation concentrates the salt in the sea, causing the water to become salty. At the same time, some salt is deposited on the seabed, which maintains the balance of salinity in the water - otherwise, the sea would become saltier every year.
The salinity of the water or the salt content of the water varies depending on the position water resource. The least salty seas and oceans are in the northern and south poles, where the sun doesn't shine as much and the water doesn't evaporate. In addition, the salt water is diluted by melting glaciers.
In contrast, the sea near the equator evaporates more due to the elevated temperatures that prevail in this area. This factor not only answers 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 saline during the 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 causes of the salinity of sea water, as scientists understand them modern level scientific knowledge. However, there are several unresolved issues. It is unclear, for example, why different salts are found throughout the world in almost the same proportions, although the salinity of individual seas varies significantly.
Are these hypotheses true?
Of course, no hypothesis is completely correct. Sea water has been formed over a very long time, so scientists have no reliable evidence about the reasons for its salinity. Why can all these hypotheses be refuted? Water washes away the land where there is no such high concentration of salt. During geological epochs, the salinity of water changed. The salt content also depends on the specific sea.
Water is different - 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 vary. Average density sea water is 1.025 g/ml, it freezes at a temperature of -2°C.
The question may sound different. How do we know that sea water 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 Sant Carles de la Rápita and go to the bay, you will see white mountains formed from salt extracted from sea water. If mining and trade in salt water 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). It has been scientifically proven that table salt (sodium chloride) is a vital substance. Even without precise chemical and medical analyzes and research, it was clear to people from the very beginning that salt was a very valuable, useful and supportive substance that allowed both themselves 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 into their roots. As a result of excessive soil salinity, for example in Australia, desertification is widespread.
If you taste water from the seas and oceans, you can feel the salty taste. Moreover, each of these reservoirs has its own taste, which differs in the degree of “salinity”. The fact is that different seas and oceans contain different amounts chemical elements. The composition of these elements depends on the composition of the seabed and the land washed by the ocean.
Where did the salt come from in the sea?
Surprisingly, sea water contains, in addition to salts, almost all the elements periodic tables. For example, in addition to sodium and chlorine, which are part of ordinary salt, water contains substances such as magnesium, calcium, potassium, bromine and a huge number of other elements.
But to the question: “ Why is sea water salty?“Scientists tried to answer back in ancient times. Many believe that the salt was carried along with river flows into the sea. And they, in turn, washed minerals from the soil. In addition, salt is also found in the rocks that make up the sea and ocean floor. Perhaps it got into the water from there.
The average salinity of all oceans and seas is 35 grams of salt per 1 liter of water. But in the water of different seas and oceans different quantities salt. The most “low-salinity” waters are the waters of the Gulf of Finland and Baltic Sea. The Red Sea is the saltiest.
Dead Sea
However, not only seas and oceans, but also lakes can be salty. For example, a lake called Dead Sea, saltier than Red sea. Another interesting fact is that the more sodium and chlorine the water contains, the better it pushes out bodies that get into it. Therefore, it is best to learn to swim in the Dead Sea.
IN salty waters the quantity and composition of chemical elements remains practically unchanged all the time. Therefore, marine inhabitants are very picky. If you put a fish from one sea to another, it is unlikely to survive.
Where do salty rivers flow?
Although river water tastes fresh, it nevertheless contains a small amount of salts. But in one of the tributaries of the Siberian Lena River The water is salty, like sea water. Therefore, the name of the tributary is appropriate - Solyanka. But the streams flowing into it are even saltier - hydrologists have calculated that, on average, their water contains 21 grams of salt per liter. The unusual phenomenon is explained by the fact that the water feeding them passes through powerful salt marshes up to 17 meters thick. These are the remains of an ancient sea that dried up millions of years ago.
Everyone knows that the water in the sea is salty. But probably not everyone knows why the water in the sea is salty. To answer this question, you need to understand where water comes from in the seas and how the seas, oceans and rivers are filled. The seas are filled with rivers, and the rivers have fresh water. But why then is the water in the seas salty?
Seas and oceans consist of water containing varying amounts of salts. Sea water has a bitter-salty taste. On average, 1 liter of sea water contains about 35 grams of salt. However, even in the same place, the salt content in the water varies depending on the time of year.
The water in the river also contains salts, only much less salt than in sea water. Many rivers originate from springs and underground sources. Underground water is purified and becomes clean and fresh, it contains little salt. This is how rivers are filled with water, which then flow into the seas and oceans, filling them with their waters.
The seas are filled with rivers and almost everything that ends up in the sea remains there for the time being. It's all about the evaporation of water. Any water is constantly evaporating. If you look at the globe, you will find that seas and oceans occupy the bulk of the planet's surface. Thus, the main part of the evaporation of water occurs over the seas and oceans, which means that salts will remain in the sea, only a small part will settle along the islands and coastlines. Evaporation of water in rivers and lakes also occurs constantly, only the evaporated precipitation mostly settles just above the ground, only a small part ends up back in the river or lake.
Thus the seas and oceans are filled fresh waters rivers with low salt content. This salt is then practically all in the seas and oceans and remains for some time. Some of the salt will be transported to the seashore with regularly occurring tsunamis and hurricanes, the frequency and strength of which depends on the amount of salt in the seawater. The concentration of salt in sea water increases gradually, this leads to the formation of various natural phenomena and with their help the salt is transferred to the earth. Thus, the degree of salinity of sea water changes slightly, and then returns to normal again, and in general the concentration of salt in sea water is almost constant, about 35 grams of salt per liter of water. Excess salt is regularly thrown onto the shore and land, and then the seas and oceans are again filled with salt from rivers and this process is constant, it was, is and will be.
Seas and oceans are a kind of sump where all waters drain. Water leaves the oceans through the evaporation of water, which rises into the sky and is carried through the air throughout the area. When evaporating, sea water becomes even more salty, since salt practically does not evaporate from the water, only a small part of the salt leaves along with evaporation. Salt and constant evaporation of water form the climate on the planet, as well as various natural phenomena with the help of which the sea gets rid of excess salt.