(3) What Are Coral Reefs ?
•Living coral colonies growing on the accumulated coral skeletons of former colonies.
•The accumulated coral growth gives rise to the largest biological constructions on earth,
e.g. The Belize Barrier Reef 220 – 250 km in length.
e.g. The Great Barrier Reef in Australia is over 2000 km long.
Corals are the architects and frame builders of the coral reef ecosystem.
Living corals provide the irregular habitat in which fish and invertebrates
can find refuge.

Skeletons of dead corals are the  building blocks of the reef structure.
These are cemented together by sand and secretions to form the ever growing
Foundation of a coral reef.

 Through as a result of sea level changes and geological process,
ancient coral reefs form what is now the land mass of many Caribbean islands,
 so substantial are the accumulations of reef material.