Coral reefs are held together by calcium carbonate. Most coral reefs are made from stony corals.Coral reefs are polyps. Corals are secret and hard carbonate exoskeleton.the economic value is 21.8 375 billion.corals reefs are also animals too.Darwin’s theory begins with an extinct volcanic island.Then the ocean and island sinks coral growth.builds a rare reef as the substance contenus. Fringing the reef gets bigger to become a barrier reef .
Where are coral reefs
The great barrier reef is a huge reef. At least 25 % of sea creatures live in coral reefs.
284 300c km are covered by coral reef.Corals are in every ocean.30s from the
Equator.coral reefs can be also be found in The red sea, florida reef tract gulf stream,and lord howe island..In tropical ocean coral reef gentilly found. Coral reef are about 150 feet below the water. Coral reefs live in waters 68 820f 20 2 8c which is often located on the east side of land.