How Many Types Of Coral Reefs Are There?

By Joseph Kiprop on August 10 2018 in Environment

Coral reefs are utilized by 25% of the ocean's creatures.

Coral reefs are some of the most complex and varied ecosystems found anywhere in the world. They are a significant magnets for tourists who are attracted by the beauty and the diversity of the wildlife found within the coral reef ecosystem. Coral reefs fall into four major categories. The classification of coral reefs dates back to the time of Charles Darwin who also wondered why coral reefs were only found in some regions of the world and not in others. When choosing the group to which a reef belongs, the primary factor put into consideration is the morphology, as in the inward and outward appearance. Despite variations in type, coral reefs located in the same region are usually home to similar species of plants and animals.

Types of Coral Reefs

Fringing Reefs

One of the most common types of coral reefs is the fringing reef. The most distinct feature of the fringing reef is that they usually have no lagoons and if a lagoon is present it is generally very shallow. Several fringing reefs extend directly from the shoreline, and in this case, there is no lagoon. The other type of fringing reef grows away from the shoreline with notable examples found in the Bahamas. Fringing reefs are composed of two key components: the reef slope which is also referred to as the fore reef and the reef flat which is also referred to as the back reef. The back reef is usually the widest part of the reef while the reef slope is steep and located closest to the ocean. One of the most common fringing reefs, which is the most extensive and contiguous in the world, is located in Kenya close to Msambweni.

Barrier Reefs

Barrier reefs are some of the most well-known types of coral reefs and are located in varied regions of the world. Their most distinguishing feature is that they are isolated from the shores by a lagoon of considerable depth. They have some similarity to the advanced stages of the fringing reefs though they contrast primarily in size. The world's most famous barrier reef, the Great Barrier Reef within Australian waters, is visible from space.

Platform Reefs

The third type of coral reef is the platform reef which generally grows either on the continental shelf or in the open ocean with some being found close to 124 miles from the shoreline. Platform reefs do not have a single consistent size with several of the larger ones extending a couple of miles across while the smaller ones are some feet across. In some cases, platform reefs are situated behind barrier reefs.


The term atoll refers to a coral reef that has a distinct ring shape which usually wholly or partially encloses a lagoon. The Indian Ocean and Pacific Ocean have the majority of the world's atolls. Within the Atlantic Ocean, the only significant group of atolls is located east of Nicaragua. The most significant atoll structure globally is referred to as the Great Chagos Bank and is situated in the Indian Ocean where it occupies an area of about 4,881 square miles.

Importance of Coral Reefs

Coral reefs are known as the "rainforests of the sea" due to their roll as one of the most diverse ecosystems in the world. About 1/4 of all marine species are found within coral reefs although they make up less than 0.1% of the ocean's surface. Economically, they are one of the most important features found in the ocean. Not only do they provide shoreline protection by absorbing wave energy but they are also important for fisheries and tourism. Vast numbers of tourists journey each year to coral reefs generating vast amounts of foreign exchange.

It is important to remember, however, that coral reefs are exceptionally fragile. As they are sensitive to changes in water temperature, climate change poses a great threat. Other sources of danger to coral reefs include ocean acidification and pollution from plastics, sunscreen runoff, and pesticides.

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