Why is the ocean salty ?

Some areas of the ocean are saltier than others . Sometimes if there is mussels living at the bottom of water can make it salty . Some rivers / pools are about four times as salty as seawater . As the rain hits the rock , acids in the rainwater break down the rock . Lots of the dissolved rock , are removed from the water . Others are not removed and are left for long periods of time . Together, they make up over 90 % of all dissolved rock in the ocean . Stated in another way, about 3.5 % of the weight of seawater comes from the dissolved salts from the rainwater off the rocks . In a mile of seawater , the weight of the salt would be about 120 million tons . If some of the salt in the ocean could be removed and spread evenly over the Earth’s land surface it would form a layer more than 500 feet thick , about the height of a 40-story office building .

BY ROSIE B