Why is water in the rivers of fresh water and sea salt?
First, talk about what kind of water is considered salty, and some fresh. The salt content in the water measured in parts per million (‰). For example, in place of the salt on the planet, the Dead Sea, salinity varies from 300 to 350 ‰, that is – in one liter of water to dissolve 300-350 g salt. Fresh liquid is considered, where the salinity is less than 1 ‰. Etalon salinity, which is used to calibrate the instrument, taken in the Bay of Biscay, where it is 35 ‰. For example: the Atlantic – 35.4 ‰, the Pacific – 34.5 ‰, the Red Sea – 41 ‰, the Mediterranean Sea – 39 ‰, Black – 18 ‰, Azov – 11 ‰.
Why is the sea salty? There is a basic version. It is believed that the increased volcanic activity was observed during the formation of the crust. Gases containing chlorine vapors, fluorine and bromine, by reacting with water formed acid. Acid reacts with solid rocks ocean bottom, as a result of there salts. Approximately 500 million years ago the composition of the water has stabilized – it has become a relatively salt.
And of course, a small amount of salts are brought into the sea by rivers.
The main reason why the water in the rivers of fresh water, is water that does not contain salt. This contributes to the water cycle, which lasts more than one million years.
Rain is on its way is mixed with dust, removes plaque from the different surfaces in contact with diverse minerals that seep into the ground. As a result, water is enriched with all sorts of impurities, including salt. The streams and streams of water fall into the river, and it carries their waters to the sea (in coastal areas, river water is somewhat desolate). Under the influence of the Sun, the water from the surface of the world ocean evaporates, and the salt remains. Atmospheric water in the form of precipitation that does not contain salts, again pours out on the continent.
In the continent of the sediments, mountain glaciers form, where some rivers are born.
The preciputes feed the ground and ground water of the Earth. In some places, the other part of the rivers on the planet begins, is Rodnikov, lakes, swamps. If in the stream and there are various dissolved salts or penetrated something or got into the river, then, first, it is in small quantities, and secondly, the current is gradually demolished towards the sea and the concentration on the way decreases. And in the sea-ocean, water evaporates from the surface, the salt remains, the cycle repeats.