Hard corals tend to secrete calcium carbonate underneath their bodies. This turns into a hard, rock-like structure upon which other coral larvae can settle. Over time, as the calcium carbonate builds up and corals reproduce, the size of a coral reef grows.
As a coral reef begins to grow, other animals and species are also attracted to the diverse habitat and find places to settle and call home. Over 25% of all marine life can be found on coral reefs. Each plays a unique role in helping to keep the ecosystem healthy and intact.