(Music) JOAN CARTAN-HANSEN, HOST Just as there are different habitats on land, there are different habitats under the ocean.
There are seagrass meadows.
These are found in shallow waters and are home to hundreds of species.
There are kelp forests.
Kelp forests are found not far from 20 percent of the world's coastlines.
And while it looks like a plant, kelp is actually a type of brown algae.
There is the intertidal zone, the habitat between low and high tide.
And the estuary zone, a habitat with a mixture of salt and fresh water.
And there are reefs.
A reef is an underwater ridge.
It can be made of rock, coral, or oyster.
Coral reefs are particularly important.
They're found in less than one percent of the ocean but are home to more than 25 percent of the ocean's plants and species.
Coral reefs are in trouble because they're easily damaged by climate change and human interactions.
And because reefs are an essential habitat, scientists are creating artificial reefs to give some creatures a new home.
And finally, there's the open ocean habitat.
This zone has nothing but water and sea creatures.
For more information about oceans, check out the Science Trek website.
You'll find it at ScienceTrek.org