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 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 confident that the Indian Ocean is the saltiest. 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 the Atlantic Ocean, as many information networks say, "disappears." 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. It should be noted that the maximum percentage of the salinity of the Pacific Ocean 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.
I remember it was in the third grade, in the natural history lesson. The teacher told us that there are rivers on earth with fresh water, as well as seas and oceans with salt water. " Why is the water in the ocean salty?"- I asked and, oddly enough, Nadezhda Konstantinovna was confused. She simply did not know the answer to this seemingly simple childish question. And then for the first time I realized that teachers do not know everything in the world.
Ocean As I got older, I tried to find an answer on my own using textbooks, an encyclopedia and the magazine “Around the World” (no one thought about the Internet at that time). And I realized that in vain she blamed the teacher for incompetence: it turns out that science still does not have an exact answer about the reasons for the salinity of ocean water.
Why ocean water is salty: hypotheses
Actually, the answer to the question, why ocean water tastes salty , is obvious: because there is a lot of salt in it. But with the fact where it came from there in such quantities, I will try to figure it out. Here main versions of the origin of salt in ocean water:
- volcanic;
- river;
- stone.
I'll tell you more about each of them.
Ocean water salty due to volcanoes
Millions of years ago when earth surface has not yet taken on its present shape, nand our planet had many active volcanoesfrom which acidic substances were thrown into the ocean water. Entering into different reactions, these acids turned into salts, which dissolved in the waters of the oceans.
A volcano in the ocean Here is the first answer to the question, p why in the seas and oceans salt water. The 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 that it should dilute the ocean water, making it less salty! " Actually, 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 rainwater is added to them. But on the way to the sea, the river collects a small amount of salt from sand and stonesthat covered its bed. Flowing into the ocean, the river gives him this salt.
The river flows into the ocean Evaporation processes in the ocean are much more activethan in rivers because of their huge surface. Turns out that fresh water evaporates, but salt remains. The ocean water is salty due to the erosion of stones
In fact, this version explains rather 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 coastal stones water particleswhich, evaporating, they turn into salt crystals... Gradually holes are formed in the stones and holes that become more and more salted... Over the years the stones collapse, and the salt returns to the ocean again.
Stones on the coast For me personally, all these options for answering the question, n why ocean waters are salty, look controversial, but science has no others yet.
If all the oceans were dried out, the remaining salt could be used to build a wall 230 km high and almost 2 km thick. Such a wall would be able to circle the entire globe along the equator. Or another comparison. The salt of all dried up oceans is 15 times larger than the entire European continent by volume!
Common salt, obtained from sea \u200b\u200bwater, salt sources or in the development of rock salt deposits. Sea water contains 3-3.5% salt. Inland seas such as the Mediterranean Sea and the Red Sea contain more salt than the open seas. Dead Sea, occupying only 728 sq. km., contains approximately 10 523 million tons of salt.
On average, a liter of sea water contains about 30 g of salt. Rock salt deposits in various parts of the earth were formed many millions of years ago as a result of the evaporation of sea water. For the formation of rock salt, it is necessary that nine-tenths of the volume of sea water evaporate; it is believed that inland seas were located at the site of modern deposits of this salt. They evaporated faster than new seawater came in - and that is why rock salt deposits appeared.
The main amount of edible salt is extracted from rock salt. Usually, mines are laid to the salt deposits. They are pumping through the pipes clean waterwhich dissolves the salt. This solution rises to the surface along the second pipe.
Which ocean has the saltiest water?
The most salty of all the oceans on Earth is the Atlantic Ocean. Despite the fact that it collects fresh water from several continents, the average salt content in the Atlantic waters 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 - 34.56%. True, in the northwestern part of the Indian Ocean water salinity reaches 42%, but in the south, in the Antarctic region, this figure is much lower.
In the Atlantic Ocean, whose area is 92 million square meters. km, salt is "distributed" more evenly. Although here, too, the salinity of the water is different and depends on the amount and regime of precipitation, evaporation, underwater currents, and the high 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. The least salty water in the Atlantic Ocean off the coast of 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 sources. The largest source of fresh water is the 90 sq. M. Wide freshwater window. m - located east of the Florida Peninsula.
Water covers a large area of \u200b\u200bour 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. In the course of geological history, the salt content in the sea has gradually increased. The Baltic Sea, due to low water temperatures, 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 75 m high coherent layer around 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 Air Force, 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 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 are washed out of them, which the rivers carry to the seas (the rocks on the seabed have exactly the same effect);
- 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 the so-called regions. 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 balance of the salinity of the water - otherwise, the sea would become more saline every year.
The salinity of water or the salt content of 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 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 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 scientists understand them 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 have no reliable evidence about the causes of 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 pool" ...
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 studies, 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.