Scientists have not finally established why the seas and oceans are salty, but more or less plausible versions exist.
Most experts are inclined to believe that this was due to the washing out of sodium from the earth's rocks by rivers. If there was no current in the rivers, they would also become salty. Then volcanoes worked, emitting chlorine into the atmosphere and, accordingly, into the water. As you know, the chemical formula of salt is NaCl.
But it is not entirely clear from this hypothesis - why is there no salinization of water at present, and the percentage of this chemical element is constant?
Other researchers believe that the oceans and seas became such initially, during the period of violent volcanic activity, but at the moment everything has already ended.
There are also very strange versions. Allegedly, in ancient times, all the waters were salty, but animals for many years of evolution "consumed" all the salt of rivers and lakes. Following the example of how artiodactyls are always ready to use it.
The seas and oceans contain different amounts of NaCl. It depends on many factors - precipitation, the vital activity of microorganisms, melting of glaciers, photosynthesis of algae.
The saltiest seas are the Red, Mediterranean, Caribbean, and the freshest are the Baltic and Kara.
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A large amount of salt in the sea can keep a person afloat, even if he cannot swim. Therefore, because of the shores of the Red Sea, which are in Egypt, their resorts are so popular. The salty water of the seas and oceans still brings great benefits to man. Starting with the fact that such water is simply good for health. In some countries, poor in fresh water resources, it has to be desalinated. But, nevertheless, this is a dead-end path due to the high cost of this process, and most importantly, because of the large amount of waste.
However, although the oceans and seas are salty, they bring endless benefits to humans due to their richest natural resources.