Geological evidence, as represented in the fossil record, shows that ancient coral reefs were as complex an ecosystem as modern day reefs. Present day reefs are considered one of the two most productive natural systems in the world, the other being the tropical rain forests. Both these systems are currently at risk as a result of excessive and negligent use. Coral reefs are increasing in economic value and must be protected. Understanding and care will ensure their survival.
Coral reefs are the largest natural structures in the world.
The polyp, resembling a small sea anemone, is able to feed itself using stinging cells found on its tentacles which paralyze passing plankton. The plankton is digested but supplies only a small part of the nutritional requirements of the polyp. The remainder comes from the zooxanthellae which convert sunlight, carbon dioxide and their own wastes into oxygen and carbohydrates. These carbohydrates are also used by the polyp to make calcium carbonate in a process known as calcification. This material forms the skeleton of the coral and eventually the framework of what we recognize today as a coral reef.