Oceans cover about 70 percent of the Earth’s surface and about 97 percent of all water on and in the Earth is saline—there’s a lot of salty water on our planet. By some estimates, if 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 (166 meters) thick, about the height of a 40-story office building. But, where did all this salt come from? Salt in the ocean comes from rocks on land. Here’s how it works:

From precipitation to the land to the rivers to the sea….

The rain that falls on the land contains some dissolved carbon