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Effects of Coral Bleaching

Effects of Coral Bleaching

Introduction

Coral Bleaching is a process biological in nature and can be difficult to explain in layman’s terms. Coral bleaching has become one of the most recognized topics within the environmental community in the last couple of years. To put it in simple terms,  coral bleaching is causes by the healthy coral reef losing its tiny, single-cell algae and usually occurs quite suddenly.  Coral bleaching is known to be responsible for killing approximately 18% of the worlds coral reefs.  Coral bleaching in most cases is triggered by the introduction of warmer waters than normal to the local eco-system.

Damage To Reefs

Coral reefs provide us with food, safe moorings and opportunities for recreation. Most importantly coral reefs are home to approximately one quarter of all life known in the ocean world. When reef building occurs in warmer, shallow tropical water, corals in this situation tend to be more sensitive to changes in their environmental conditions. The corals lose their colour and the skeleton left behind is white in colouration. This colour is amplified when sunlight strikes it. Once the coral dies and only the skeleton is left normal wave activity will reduce the reef to what is known as coral rubble. Tropical storms can accelerate this process. The change in the reef system is dramatic. What was once a healthy eco-system with a variety of species inhabiting it is reduced to a weak coral community usually with algae as the dominating species of plant life. If by chance or with human intervention the stress on the reef is lessened, many times the reef has a good chance to recover. Recovery does not happen overnight and can take many years to occur. Prevention of coral bleaching is much easier to accomplish than recovery.  Corals inhabiting the water surrounding the Galapagos Islands were observed to bleach at temperatures of 29 degrees Celsius, a full degree and a half warmer than the critical temperature for bleaching at that site. Not all coral bleaching occurs in shallow, warm waters. Some cases of bleaching have occurred in corals growing near the limits of their ability to sustain themselves in cold waters. These bleaching events were suspected to be caused by severe storms pushing colder waters into the reef system from deeper levels in the ocean. Corals are very resilient and  can often recover from bleaching episodes that are short in duration, if they are exposed to longer, or multiple bleaching the results can be nothing less than fatal.

Conclusion

Many people feel that with the increase in temperatures due to climate change that coral bleaching will not only increase in frequency, but has the ability to become an annual event. Many agree this could happen as soon as the year 2030.  Coral bleaching, if it continues, will threaten coral reefs around the world whenever the weather conditions are unusually hot, and will affect not only reefs that are under stress by human usage but also the most remote and pristine reefs so far untouched by human hands.  This is a recipe for  disaster for any and all reefs. Growth for a reef occurs slowly. Typically reefs can generate approx one inch of growth per year. Any interruption to this slow growth only weakens the coral and severely limits it’s ability to cope with environmental change..