We take it for granted but have you ever wondered why sea is salty? Does it serve any purpose being that way?
Well, as it turns out, no. The salt in the seas and oceans comes from rocks on land.
The rain that falls on the land contains dissolved carbon dioxide which comes from the surrounding air. This causes the rain to be slightly acidic. Therefore when it rains, some parts of the rocks are eroded and break down due to the acid rain. This process creates ions that are carried away in runoff to streams and rivers and, ultimately, end up to the seas and oceans. Two of the most prevalant ions in seawater are chloride and sodium. Together, they make up more than 90% of all dissolved ions in the ocean. Sodium and Chloride are ‘salty.’ So, how much salt there is in seawater? (the article continues after the ad)
About 3.5% of the weight of seawater comes from the dissolved salts. Theoretically, if all the salt in the oceans could be removed and spread evenly over the Earth’s surface, it would form a layer about the height of a 40-story office building.