The Nature, Structure and Threats facing Coral Reefs

The Nature, Structure and Threats facing Coral Reefs
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Definition of Coral Reefs
In the oceans, there exist calcium carbonate structures secreted by corals. The calcium carbonate forms structures that hold the coral reefs together. Coral reefs are comprised of a collection of tiny animals that belong to the cnidaria group. Unlike other sea organisms that have a soft body cover, corals are covered in a hard exoskeleton. The polyps that live in the corals are therefore well protected from any predators (Dubinsky and Stambler, 2010). Coral reefs occur in different types and they exist in varying ecosystems. The types include barrier, fringing and atoll coral reefs. Coral reefs exist in three zones namely, reef crest, reef lagoon and fore reef that are ecologically or physically linked. Some thrive well in shallow waters, providing a home for various marine organisms (Sale, 2006). Others do well in cold waters and deep waters as well. Coral reefs are beneficial to the ecosystem since they act as tourist attraction and protect the shoreline and fisheries (Levy, 2008). Some coral reefs are very sensitive to the variation in temperatures. The global warming that has resulted to climatic change is therefore a threat to the survival of coral reefs (Isabelle and John, 2006). Human activities such as oceanic acidification also pose a threat to the coral reefs.
The Structure of Coral Reef
Calcium carbonate is the main component of coral reefs. The limestone is absorbed from the surrounding water by coralline algae and colonies of polyps. Most of the component in the foundation of the coral reefs is dead matter composed of dead skeletons of corals (Hopley, 2011). On top of the coral skeletons is the living matter composed of groups of tiny polyps. Most of the coral reefs are beautiful because of the presence of coral polyps that have colorful tentacles. The algae found in the tissues of majority of the animals also contribute to this beauty (Muzik and Katherine, 1992). The size of the coral reefs varies with the species available since they all have different growth rates. The growth rate ranges from one to twenty centimeters per year. The growth rate in the cold waters is mostly slower than the rate of the coral reef found at warmer areas (Spalding and Corinna, 2001). Other environmental factors such disease, sedimentation, sunlight, rising temperatures and salinity of the water also affects the growth rate of coral reefs. As they grow, the corals change to different forms. These forms include free living, encrusting, laminar, columnar and branching (Birkeland, 2006). The morphologies determine the shapes of the coral reefs.
Types of coral reef
The reef slope and the reef flat form are the main zones of the fringing reef found mostly along the shoreline (Spalding, 2004). This type of coral reef has a shallow backreef or none at all, a fact that distinguishes it from the other major coral reefs. It is the most common type and it is believed to be the first one to exist on a landmass (McClanahan, Sheppard, and David, 2000). The barrier reef is the other common type of coral reef. It is very similar to the fringing reef except that it is found further away from the shore. Besides, some of ...