Coral Reef Biome

Coral reefs are beautiful, colorful structures found in warm ocean waters. They are built by tiny animals called coral polyps. Over many years, these tiny builders create massive reefs. Coral reefs are home to about 25 percent of all ocean species.

How Reefs Form

Coral polyps are tiny soft animals related to jellyfish. They build hard skeletons around themselves for protection. When polyps die, new ones grow on top. Over thousands of years, this creates a huge reef structure. Reefs grow very slowly, only about an inch per year.

Reef Life

Coral reefs are bursting with life and color. Clownfish, parrotfish, and sea turtles all live there. Sponges, sea stars, and anemones cling to the reef. The bright colors of the reef come from tiny algae that live inside the coral.

Fun Facts

• The Great Barrier Reef in Australia is so big it can be seen from outer space.
• Coral reefs cover less than 1 percent of the ocean floor but support about 25 percent of all marine species.
• Some coral reefs are over 5,000 years old.

Did You Know?

Coral can bleach and turn white when the water gets too warm. This is called coral bleaching, and it can kill the reef if the water does not cool down.