Ocean water: fresh or salty? What kind of water is in the oceans: salty or fresh?

Why is the water in the ocean salty and the water in rivers fresh? The answer to this question is ambiguous. Exist various points perspectives that reveal the essence of the problem. According to scientists, it all comes down to the ability of water to destroy rock and leach easily soluble components from it, which end up in the ocean. This process occurs continuously. 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 comes down to the fact that all the salts dissolved in the water are carried by rivers into the ocean, saturating the sea water. There are 70 times less salts in river water, so it is impossible to determine their presence in it without special tests. It seems to us that the river water is fresh. In fact, this is not entirely true. Saturation sea water salts happens all the time. This is also facilitated by the process of evaporation, as a result of which the amount of salts constantly increases. This process is endless and lasts about two billion years. This 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 thing! Sea water contains salts of hydrochloric acid, and river water contains carbonic acid. That is why scientists have put forward an alternative hypothesis. They believe that sea water was originally salty, and rivers have absolutely nothing to do with it. This is all due to volcanic activity, the peak of which occurred at the time of the formation of the earth’s crust. Volcanoes released huge amounts of steam saturated with acids into the atmosphere, which condensed and fell to the ground in the form of acid rain. The sediments saturated the seawater with acid, which reacted with the hard basaltic rocks. As a result, huge amounts of alkali were released, including sodium, potassium and calcium. The resulting salt neutralized the acid in seawater.

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 carbonates that enter the ocean with river water serve as an ideal building material for marine organisms. They build coral islands, shells, and their skeletons from it.

Which hypothesis to choose is a purely personal matter. In our opinion, they both have a right to exist.

Since ancient times, the composition of water in the seas and oceans has surprised people. In Germany, there are legends that claim that at the bottom of every sea there is a magical salt mill, and in Hungary - that this is all because of the tears of an unfortunate girl grieving under the water.

Finding out whether the water in the ocean is salty is actually as easy as shelling pears - just refer to the materials modern research. Indeed, sea and ocean water is very salty, and sometimes the concentration of salts is excessively high: one glass of “drink” from the Dead Sea is enough to prevent you from regaining consciousness at all.

The saltiest bodies of water in the world are:

Atlantic Ocean: southern part (salt concentration is 37.9 ppm) and northern part (37.6);
Pacific Ocean: southern part (36.9) and northern (35.9);
Entire Indian Ocean (36.4 ppm).

Why is the ocean water salty?

Oddly enough, even modern scientists have not found a clear answer to such a simple question - why is the water in the ocean salty? Some researchers believe that this is due to volcanic activity, while others believe that salt comes into the oceans through rivers and seas.

Two theories

The first group of scientists claims that a very long time ago, when Earth's crust just formed, volcanoes on Earth were extremely active. Their eruptions led to the occurrence of acid rain - but the World Ocean itself consisted of acids. As a result, various complex substances “collided” with each other, and as a result of the reaction, ocean waters became safe for life, which had yet to arise. But only very salty ones.

As for the “earth” theory, it says that salts are contained in all reservoirs of the world. And indeed it is - fresh water is not devoid of salts, there are just very few of them. Flowing into the oceans, rivers and seas bring with them salts washed out of the soil. They, in turn, remain in place - and where else can they go? Yes, during the natural cycle, water evaporates from the surface of the oceans, but the salts are too heavy to follow it.

As you can see for yourself, these theories are quite logical. Or maybe both groups of researchers are right at once, and the salts first appeared thanks to volcanoes, and numerous currents brought even more of them?

Can a fresh ocean arise?

What determines the salinity of water in the ocean? Many factors play a role here, including underwater currents, the presence of glaciers, the intensity of their melting, the activity of evaporation, etc. In addition, in the depths, under the very bottom of the ocean, there are deposits of the purest fresh water.

But even if we imagine that a crystal clear body of water will appear on Earth, it is obvious that fresh water in the ocean would not linger for long. After all, no one doubts that rivers constantly add salts washed out of the soil into ocean waters - scientists are skeptical only that this could cause the appearance of vast salty reservoirs as such.

Is it possible to drink sea water

So, we figured out why the water in the seas and oceans is salty, and found out that drinking it is not recommended. But why does this limitation exist?

In fact, ocean water is contraindicated for humans due to the structural features of the body. The kidneys are responsible for removing salts and other “heavy” substances from food, which may simply not be able to cope with the excess load. And a liter of sea water contains more than 30 grams of salt! That is why unfortunate people who are shipwrecked and manage to escape in boats often die of thirst in the middle of the water.

Moreover, the characteristics of water in the oceans are not stable and are constantly changing. Another important point— in different parts of the same ocean, water can vary quite significantly in composition.

Where does salt come from in the oceans? The source of salts entering the ocean are the rivers flowing into it. Salt is washed out of rocks and soil by rivers and then enters the ocean. But the water in rivers should also be salty? This is true.

It’s just that if the salt content in water is below one ppm, it is considered fresh. Over many thousands of years, fresh water accumulated in the ocean, and when the water evaporated, the salt remained in it, so it reached such values that the salinity level reached several tens of ppm.

Climatic conditions have the greatest influence on the level and distribution of salinity, and this parameter is directly dependent on ocean currents.

Surface ocean waters in areas where there is no direct influence from land can range from 32 to 37.9 ppm (3.2-3.79%).

In the ocean, the amount of water moving in and out of land, as well as precipitation, evaporation and condensation, have a direct impact on salinity levels. The balance of fresh and salt water in the ocean can be positive or negative.

The greatest decrease in salinity is observed near the equator, because this zone receives a significant amount of precipitation and evaporation is not very intense.

Towards the north and south of the equator, the salinity of water gradually increases.

Winds, precipitation, pressure - all these factors influence the level of salinity in the ocean. Warm ocean currents increase salinity, while cold ocean currents decrease it. On average, the Atlantic Ocean is considered the saltiest - 35.3 ppm. The Arctic Ocean is the freshest of all.

The most salty areas of the oceans:

Atlantic Ocean, southern part - 37.9 ppm
Atlantic Ocean, northern part - 37.6 ppm
Indian Ocean - 36.4 ppm
Pacific Ocean, northern part - 35.9 ppm
Pacific Ocean, southern part - 36.9 ppm

Is fresh water found in the ocean? The level of ocean waters was not always the same. Many thousands of years ago, the level of the world's seas was much lower than it is now. After the glaciers melted, it increased, but in the depths, under the ocean floor, quite large deposits of fresh water remained.

The world's oceans and fresh water are interconnected things. In which ocean can fresh water be found? There are quite a lot of such places, but extracting fresh water from the ocean depths requires complex equipment. Essentially similar to mining.

The only difference between ocean fresh water and ordinary water is that ocean water still contains a certain amount of salts (about 10 ppm).

Therefore, in conditions of a deteriorating environmental situation and a lack of fresh water, the ocean can become a source of valuable water reserves.

Why is the water in the ocean salty: hypotheses

Actually, the answer to the question is, why does the ocean water taste salty?, is obvious: because it contains a lot of salt. But I’ll try to figure out where it came from in such quantities. Here The main versions of the origin of salt in ocean water:

volcanic;
river;
stone.

I'll tell you more about each of them.

The ocean water is salty due to volcanoes

Millions of years ago, when the earth's surface had not yet taken on its current shape, nand our planet had many active volcanoes, from which acidic substances were released into ocean water. Entering various reactions, these acids turned into salts, which dissolved in the waters of the world's oceans.

Volcano in the ocean Here is the first answer to the question, p Why is there salty water in the seas and oceans?.

Ocean water is salty because of the rivers that flow into it.

“How so? - you ask - the water in the rivers is fresh, which means it should dilute the ocean water, making it less salty! In fact, river water cannot be considered absolutely fresh: it contains salts, but in small quantities. Rivers take their water from streams that flow from underground freshwater reservoirs. Fresh water is added to them rainwater. But on the way to the sea the river collects a small amount of salts from sand and stones, with which its bed is covered. Flowing into the ocean, the river gives it this salt.

The river flows into the ocean Evaporation processes in the ocean are much more active than in rivers due to their enormous surface area. It turns out that fresh water evaporates, but salt remains.

Ocean water is salty due to erosion of rocks

In fact, this version explains not the origin of ocean salt, but the stability of its concentration. The seas and oceans have enough a large line of shores that are constantly washed by waves. The waves leave on particles of water on coastal stones, which, evaporates and turns into salt crystals. Gradually, holes form in the stones and holes that are getting more and more salty. Over the years the rocks are destroyed and the salt returns to the ocean.

Stones on the coast

For me personally, all these options for answering the question, p why ocean waters are salty, look controversial, but science has no others yet.

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.

Consequently, when river water enters the sea, 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 seawater makes up the largest amount on the planet. For this reason, many people strive to relax on sea beaches, 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. This is an insignificant amount considering 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.

If all the oceans were dried up, the remaining salt could be used to build a wall 230 km high and almost 2 km thick. Such a wall could go around the entire equator. Earth. Or another comparison. The salt of all the dried up oceans is 15 times larger in volume than the entire European continent!

Regular salt is obtained from sea water, salt springs, or from the development of rock salt deposits. Sea water contains 3-3.5% salt. Inland seas, such as the Mediterranean Sea, Red Sea, contain more salt than open seas. The Dead Sea, occupying only 728 square meters. km., contains approximately 10,523,000,000 tons of salt.

On average, a liter of sea water contains about 30 g of salt. Rock salt deposits in various parts the lands were formed many millions of years ago as a result of the evaporation of sea water. To form rock salt, nine-tenths of the volume of sea water must evaporate; It is believed that in place of modern deposits of this salt there were inland seas. They evaporated faster than new sea water came in - so rock salt deposits appeared.

The main amount of table salt is obtained from rock salt. Usually, mines are laid to salt deposits. Pumped through pipes clean water, which dissolves salt. Through the second pipe this solution rises to the surface.

Which ocean has the saltiest water?

The Atlantic Ocean is considered the saltiest of all the oceans on Earth. Despite the fact that it collects fresh water from several continents, the average salt content in the waters of the Atlantic is 35.30% (i.e. 1 kg of water contains 35.3 g of salt). For comparison, the salt content in the Indian Ocean is 34.68%, and in Pacific Ocean- 34.56%. True, in the northwestern part of the Indian Ocean the salinity of water reaches 42%, but in the south, in the Antarctic region, this figure is much less.

In the Atlantic Ocean, whose area is 92 million square meters. km, the salt is “distributed” more evenly. Although here the salinity of water is different and depends on the quantity and regime atmospheric precipitation, evaporation, underwater currents, full flow of rivers. In tropical latitudes, the salinity level is higher than in the temperate latitudes of the Northern Hemisphere, where the North Atlantic Current carries its waters. Least salty water in the Atlantic Ocean off the coast South America. And all because in this place the Amazon throws millions of cubic meters of fresh water into the ocean.

In addition, the upper layers of water may differ in composition from the lower layers. For example, it is known that the Atlantic Ocean has its own fresh underground springs. The largest source of fresh water is the “freshwater window” 90 square meters wide. m - located east of the Florida Peninsula.

Finding out whether the water in the ocean is salty is actually as easy as shelling pears - just look at the materials of modern research. Indeed, sea and ocean water is very salty, and sometimes the concentration of salts is excessively high: one glass of “drink” from the Dead Sea is enough to prevent you from regaining consciousness at all.

The saltiest bodies of water in the world are:

Atlantic Ocean: southern part (salt concentration is 37.9 ppm) and northern part (37.6);
Pacific Ocean: southern part (36.9) and northern (35.9);
Entire Indian Ocean (36.4 ppm).

Why is the ocean water salty?

Two theories

The first group of scientists claims that a very long time ago, when the earth’s crust was just being formed, volcanoes on Earth were extremely active. Their eruptions led to the occurrence of acid rain - but the World Ocean itself consisted of acids. As a result, various complex substances “collided” with each other, and as a result of the reaction, ocean waters became safe for life, which had yet to arise. But only very salty ones.

As for the “earth” theory, it says that salts are contained in all reservoirs of the world. And this is true - fresh water is not devoid of salts, there are just very few of them. Flowing into the oceans, rivers and seas bring with them salts washed out of the soil. They, in turn, remain in place - and where else can they go? Yes, during the natural cycle, water evaporates from the surface of the oceans, but the salts are too heavy to follow it.

Can a fresh ocean arise?

Is it possible to drink sea water

So, we figured out why the water in the seas and oceans is salty, and found out that drinking it is not recommended. But why does this limitation exist?