What Coral reefs need to survive

Coral reefs need three things to survive.

They need warm water, sunlight, and clear, shallow waters.

Coral will not grow in waters that are lower than 68 degrees Fahrenheit (20 degrees Celsius). Sunlight and clear, shallow water is needed so that the zooxanthellae in their tissue can photosynthesize.

The zooxanthellae transfers some food energy directly to the coral’s polyps. If waters are too deep or too murky, the zooxanthellae will not get enough light to photosynthesize.

Photosynthesis is a process that plants go through to make their own sugars and starches.

Even though coral is not a plant, it still photosynthesizes to store the energy that it gets from the sugar and starch. This is why you usually don’t find coral below 100 meters (330 feet) deep.

References: http://library.thinkquest.org/CR0215471/coral_reef.htm