A reef is a coral community consisting of several thousand organisms living together. Although it looks like a dormant underwater bush, the reef is very much alive.
Reefs grow very slowly over time.
Across the globe, coral reefs cover 600,000 square miles and are home to over 500,000 species of life. There are many threats to coral reefs. Coral reefs are found only in shallow, warm water. The water temperature is usually constant year round. The reef is made up of thousands of corals.