Introduction | How Does Water Get In and Out of Oceans?
Who Needs Oceans? | When Saltwater Meets Freshwater!

Most of the life of Earth lives below the surface of the oceans. Tiny little creatures such as plankton float in the water, sharing the oceans with plants and animals including the largest animals on Earth, whales. Some swim, others float, and some walk around on the bottom or nestle into rocks, but they all make oceans their home and rely on them for food and shelter.

People need the oceans, too! Even though people live on land, many of us eat food from the oceans like fish, clams, and lobsters. We also rely on the oceans to keep Earth’s climate mild by absorbing heat so that it is comfortable for us to live.