Why is the ocean salty?

Why is the ocean salty?

Oceans cover about 70% of the Earth's surface...

and ~97% of all water on an in the Earth is saline—that's a lot of salty water!

If the ocean salt were removed & spread evenly over the Earth's land surface...

it would form a layer more than 500 feet (166 meters) thick (~40 stories high).

Salt in the ocean comes from rocks on land.

Here's how it works:

The rain that falls on the land has dissolved carbon dioxide from the air.

The rain physically erodes the rock, and acids chemically break down the rock,

and carries salts and minerals along in a dissolve state as ions.

The ions in the runoff are carried to streams and river, and then to the ocean.

For more information, visit USGS.gov