What are the six things most corals need to survive and grow?
1. Sunlight. 2. Salt water. 3. Warm water. (Reef building corals need water temperatures 68ºF-82ºF, 20ºC-28ºC.) 4. Clear, clean water. (Dirty water can block sunlight. Sediments can also choke corals so they can t feed.) 5. Shallow water less than 150 feet (46 meters) deep. (Sunlight is absorbed the deeper you go under the water.) 6. A hard surface. What is a coral reef A coral reef is a collection of different kinds of hard corals. The skeletons of hard coral polyps form the limestone (calcium carbonate) structure of the reef. The coral reef we see today may have taken hundreds or thousands of years to grow. The largest coral reef and the largest living organism on planet earth is the Australia Great Barrier Reef. In addition to coral reefs made of living organisms, coral reefs are also homes for many different kinds of plants and animals. Coral reefs are some of the most diverse ecosystems on earth. What are the three main types of coral reefs? 1. Fringing Reef: These reefs grow near
