As many know, coral reefs are a type of underwater environments. On the contrary to what most people may think though, coral reefs are made up of many living things. They also provide a home to a plethora of organisms, both of plant and animal origin. There are three different types of reefs- fringing, barrier, and atolls. Coral can be subdivided into two types- hard and soft. The following paragraphs will take a closer at all of these types and the differences between them, as well as the similarities. They will also discuss how coral reefs are formed and how they affect out ecosystems and, in turn, the world.
             At first one must understand what the difference between soft and hard coral is. It is quite simple actually. Hard corals have hard, limestone skeletons, which form the basis of coral reefs (www.enchantedlearning.com/biomes/coral 04/03/03). Soft corals do not build reefs (www.enchantedlearning.com/biomes/coral 04/03/03). Examples of hard coral would include brain coral and elkhorn coral; soft corals include sea fingers and sea whips. The three different types of reefs are as follows: fringing, barrier and atolls. These are the three types of reefs that are recognized in Charles Darwin's theory of reef formation. This is the on the widely accepted theories.
             Fringing reefs are the first type of reefs. They border the shorelines of continents and islands in the tropical seas. Commonly, they are found in the South Pacific Hawaiian Islands, and parts of the Caribbean. Fringing reefs are usually very narrow and are either adjacent to the shore or, sometimes, separated from the shore by a shallow channel (www.environnement.gouv.fr/ifrecor/domtom/debut 04/03/03).
             The next type is barrier reefs. They are much wider than the fringing type of reefs. They are separated from the shore by lagoons. Lagoons are areas of relatively shallow water situated in a coastal environment and having access to the sea but separated from t...