Corals are multicellular animals that build reefs by secreting a hard external skeleton of calcium carbonate. Reefs provide habitats for fish, sea turtles, marine mammals, crustaceans, invertebrates and other life.
Algae live in the cells of individual coral polyps and process their waste.
This ability to recycle biological material and retain nutrients in nutrient-poor environments makes the coral reef one of the most productive ecosystems on earth. However, corals have very specific requirements for light, temperature, water clarity, salinity and oxygen and their lack of mobility makes them vulnerable to environmental disturbances. I'll tell you about a University of Hawaii study on corals reefs on tomorrow's University Report, I'm Tracy Orillo Donovan.