The Importance of Coral Reefs
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| This bright coloration results from algae inhabiting the coral. |
| James Watt/NOAA |
Coral reefs provide many benefits to both animals and their environments. They provide protection for harbors and beaches from heavy waves that caused by intense coastal storms. Corals make up the core of these reefs, with many organisms depending on them for food and shelter. The ocean’s biodiversity depends on healthy coral reefs.
Corals are sessile aquatic organisms. Their calcium carbonate skeleton is secreted at the base of the polyp and is continually deposited as the coral ages. There are two types of coral: stony and soft. Stony have a full skeleton, while soft have calcium carbonate spicules scattered throughout their bodies.
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Corals can live in one of three types of reefs: atoll, barrier, or fringing. Atolls are formed by a process in which a volcano becomes submerged. During this process, the top of the volcano sinks in, creating a circular oval with a central lagoon. Barrier reefs are platforms separated from adjacent land by a lagoon or bay. Fringing reefs are the most common type of reef, projecting seaward from the shores of continents and islands.
Importantly, corals are indicators of coastal watershed health and water quality. They are extremely sensitive to changes in temperature, pH, salinity, and oxygen. Changes in coral can be indicative of a greater problem, and are affected by both natural or human induced stresses. Hurricanes are an excellent example of natural stress. While the reef is initially damaged, it may be re-colonized by a greater diversity of organisms. Natural stresses can be beneficial because they are short term and adaptable. Human induced stresses, such as waste discharge, are harmful.
Click on each image to learn more about these varieties of coral