This image of a coral reef was taken by photographers from NOAA, the National Oceanic and Atmospheric Administration in the waters off the coast of Puerto Rico. This reef is covered with a large number of elkhorn coral (Acropora palmata). Elkhorn coral is a type of coral known as an acropora. Acropora is considered to be one of the most important reef-building corals in the Caribbean Sea. The coral gets is common name from the complex branching structures that closely resemble elk antlers.