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Isabelle Bounkeua



















Coral reefs are among the oldest and most diverse ecosystems in the world.  They are called the rainforest of the sea because even though they cover only .07 percent of the Earth's surface (about the size of Texas), they support 25 % of all marine fish species. 500 million people rely on coral reefs for their food and livelihoods as well as for protection against erosion of the coast from the sea. Scientist discovered treatments for cardiovascular diseases and ulcers as well as some possible new medicines for cancer and HIV in the reefs and coral skeletons have been used as bone grafts for humans. However, if the present rate of destruction of coral reefs continues, 70% of coral reefs will be dead by 2050.

There are  different kinds of coral: hermatypic corals, ahermatypic corals, and soft and hard corals of each kind. Hermatypic corals are the colorful corals in tropical reefs that we usually conjure a picture of when we say "coral"  while ahermatypic corals usually live in the depths of the ocean and don't necessarily have any color.  When l use plain "coral" in this site I mean hermatypic corals. For details on differences between hermatypic and ahermatypic corals, see Adaptations and Relationships and for the difference between hard and soft corals see Animals: coral. 

 Overview of Coral Reef in Fiji


Reefs come in three types : Fringing, Barrier and Atoll

Fringing Reefs hug the coast 


 Diagram of Fringing Reef Fringing Reef Bora Bora NASA JPL Satellite: Space Shuttle Sensor: SIR-C/X-SAR

Barrier Reefs form further away from the cost and usually have a lagoon between it and land.

Australia’s Great Barrier Reef NASA/GSFC/LaRC/JPL, MISR Team. Satellite: Terra Sensor: MISR 


Barrier Reef Diagram



Atoll Reefs are fringing or barrier reefs that formed around an island which then sank over time leaving only a circle of reefs

Atoll Diagram View of Midway Atoll from Space Shuttle

 around a lagoon.






Coral Reefs are the largest living structure on Earth and the Great Barrier Reef is the largest at almost 2000km

(1243 mi).

  Map of Great Barrier Reef