Why Is the Ocean Salty

If you have ever swallowed ocean water, you know it tastes very salty. The ocean has been collecting salt for billions of years. Rain washes over rocks and dissolves tiny amounts of salt and minerals. Rivers carry these dissolved salts to the ocean. The water evaporates, but the salt stays behind.

Where the Salt Comes From

Rain is slightly acidic and slowly dissolves minerals from rocks on land. Rivers carry these dissolved minerals to the ocean. Another source of salt is underwater volcanoes and hydrothermal vents on the ocean floor. These release minerals directly into the water. Over billions of years, all this salt has built up.

Why It Stays Salty

When ocean water evaporates, only the water molecules rise into the air. The salt is left behind in the ocean. The water falls as rain and eventually flows back to the ocean, carrying even more salt. This cycle has been happening for billions of years, making the ocean saltier over time.

Fun Facts

• If you removed all the salt from the ocean and spread it on land, it would form a layer about 500 feet thick.
• The Dead Sea is almost ten times saltier than the ocean, so you can float in it easily.
• Ocean water is about 3.5 percent salt by weight.

Did You Know?

The most common salt in the ocean is the same as table salt, sodium chloride. But the ocean also contains many other minerals like magnesium, calcium, and potassium!