Facts About Coral Reefs
By Penny S. Harmon

Coral reefs were formed as much as 500 million years ago.



The Great Barrier Reef is only about 500,000 years old.

Coral Reefs take up under 1% of the ocean.

The Great Barrier Reef is over 2,000 meters long.

Corals have two types: hard and soft.

Coral reefs are both plants and animals. The polyp (animal) and the zooxanthellae (plant).

The plant and animal live in symbiosis, meaning they help each other to survive.

The coral polyps use calcium from the water to build their skeleton like structure.

Coral reefs are found in shallow water, although, some deeper coral reefs have recently been discovered.

The largest coral reef is The Great Barrier Reef, off the coast of Australia.

Coral animals need warmth to survive. They need a temperature of about 65 degrees (F) in order to survive and grow.

Pollution and over-fishing can help destroy a reef.

Coral reefs provide a barrier which protects the shoreline from eroding.

Human bone grafts have been done by using the limestone skeletons in coral reefs.

Reefs are home to many ocean marine animals.