Figure 1. Types of Coral Reefs

2. Conditions Needed for Growth of Coral Reefs

Corals are found throughout the oceans, from deep, cold waters to shallow, tropical waters. Conditions favourable to growth of corals reefs can be discussed as under:

1. Shallow coral reefs grow best in warm water (70–85° F or 21–29° C). It is possible for soft corals to grow in places with warmer or colder water, but growth rates in these types of conditions are very slow.

2. Reef-building corals prefer clear and shallow water, where lots of sunlight filters through to their symbiotic algae. The most prolific reefs occupy depths of 18–27 m.

3. Corals also need salt water to survive, so they also grow poorly near river openings with fresh water runoff.

4. Other factors influencing coral distribution are availability of hard-bottom substrate and the

availability of food such as plankton.