What are the different forms of coral reef?

Coral reefs can take four forms; fringing reef, platform reefs, barrier reefs and atolls.

Fringing reefs are narrow and shallow, and generally occur near the shore, they literally are a thin 'fringe' along the coast.

Platform reefs are reef outcroppings far from shore that occur in calm water. They often have a shallow lagoon, and are flat on top.

Barrier reefs are reefs growing along a coastline that are separated from the coastline by a lagoon. Barrier reefs are very similar to fringings except that they are much larger.

Atolls are ring reefs that usually form at the base of a volcano. Over time the volcano dissapears, leaving a rin of reef surrounded by deep ocean.