Why is the ocean salty but the river is not? Why is the sea salty? Ocean water is salty because of the rivers that flow into it.
Often, sailors of ships that 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 whole point 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 and salty, and is not suitable for drinking. This is all due to the salts dissolved in it. Let's figure out how they got there.
What gives water its salty taste?
Salt has a crystalline appearance. Ocean 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 (ordinary salt). This is why the water in the sea is salty. It remains to be seen how the salts get into this water.
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Scientists have been conducting experiments for a long time and trying to figure out why sea water is salty and river water is fresh. There are several theories about the formation of salty sea water.
It turns out that rivers and lakes also have salty water. But the salt content in them is so small that it is almost unnoticeable. 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 do not change their chemical composition for a long time now. And those elements that come with river water only maintain the oceanic composition, but do not change it in any way. This leads to another theory. Salt has a crystalline consistency. Waves hitting the shore wash the stones. Lures form in them. When the water evaporates, salt crystals remain in these holes. When the stone is destroyed, the salt returns to the water and it becomes salty.
Anyone who was on the beach could see that the water in the sea tasted salty. But where does salt come from if fresh water enters the ocean through rains, rivers, etc.? Why is the sea salty and has it always been like this - time to figure it out! Salinity refers to the salt content in water. Most often, salinity is measured in " ppm
» (‰). Permille 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 approximately 1000 grams) contains 27 grams of salt. Water with an average salinity of 0.146 ‰ is considered fresh. Average The salinity of the World Ocean is 35 ‰. What makes water salty is sodium chloride, also known as table salt. Among other salts, its share in sea water is the highest. The saltiest sea is the Red Sea. Its salinity is 41‰. 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 considered. Fresh water always has a small amount of salts, and rainwater is no exception. It always contains traces of dissolved substances that were captured during its passage through the atmosphere. When rainwater gets into the soil, it washes away small amounts 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 rain and brings new minerals from the land. The sea is salty because all the salts remain in it. The same principle applies to rivers. Each of them is not completely fresh, but contains small amounts of salts captured on land. Proof that salt comes through rivers are the saltiest lakes: the Great Salt Lake and the Dead Sea. Both are about 10 times saltier than seawater. Why are these lakes salty?, while most of the world's lakes are not? Lakes are usually temporary storage areas for water. Rivers and streams bring water to lakes, and other rivers carry it away from these lakes. That is, water comes in from one end and leaves from the other. The Great Salt Lake, the Dead Sea and other salt lakes have no outlets. All the water that flows into these lakes leaves only through evaporation. When water evaporates, dissolved salts remain in bodies of water. Thus, some lakes are salty because: Over many years, salt in the lake water has accumulated to its current level. Interesting fact: The density of salt water in the Dead Sea is so high that it practically pushes a person out, preventing him from sinking. The same process made the seas salty. Rivers carry dissolved salts to the ocean. Water evaporates from the oceans to fall again as rain and replenish rivers, but the salts remain in the ocean. Rivers and rain are not the only source of dissolved salts. Not long ago, they were discovered on the ocean floor hydrothermal vents. They represent places where seawater has seeped into the rocks of the Earth's crust, become hotter, and is now flowing back into the ocean. Along with it comes a large amount of dissolved minerals. Another source of salts in the oceans is underwater volcanism - volcanic eruption underwater. It is similar to the previous process in that seawater reacts with hot volcanic products and dissolves some of the mineral components. Most likely no. In fact, the sea has had roughly 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.
Everything seems clear, but at the same time, this issue There are two diametrically opposed opinions. 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. Seawater is constantly saturated with salts. 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 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 sea water. 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 the 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. The phenomena of the world around us raise a lot of questions among the curious. For example, when you find yourself on the shore of an endless body of water, you begin to think: what kind of water in the ocean is fresh or salty? How can we explain the chemical composition of ocean water and is it safe to drink? 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 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: 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. About the amount of salt and fresh water on earth. 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 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. 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? 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. 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 the unfortunate who were shipwrecked and managed to escape in boats often die of thirst in the middle of the water.
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. Clean water is pumped through the pipes, which dissolves the 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 the Pacific Ocean - 34.56%. True, in the northwestern part Indian Ocean The salinity of the water reaches 42%, but in the south, in the region of Antarctica, 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 the water is different and depends on the amount and regime of precipitation, evaporation, underwater currents, and the fullness of rivers. In tropical latitudes, salinity levels are higher than in temperate latitudes Northern Hemisphere, where the North Atlantic Current carries its waters. Least salty water in 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 freshwater underground springs. The largest source of fresh water is the “freshwater window” 90 square meters wide. m - located east of the Florida Peninsula.How is water salinity determined?
Where does salt come from in the seas and oceans?
Rains and rivers
Confirmation of the theory - salt lakes
Hydrothermal processes
Submarine volcanism
Will the seas be saltier?
Why is the water in the ocean salty and the water in rivers fresh? The answer to this question is ambiguous. There are different points of view 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.
Why is the ocean water salty?
Two theories
Can a fresh ocean arise?
Is it possible to drink sea water
Why is the sea salty: Video