Why Are Coral Reefs Disappearing?
Coral reefs are some of the most complex and diverse ecosystems on the planet, according to the Environmental Protection Agency. Because of that, reefs often boost economies in their areas by drawing tourists. Reefs also protect coastlines and shores from flooding and provide scientists with new medicines, but in spite of their importance, coral reefs are disappearing.
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Formation
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Coral reefs are formed by small animals called polyps. Although polyps are considered an animal, they are stationary. When a polyp affixes itself to an area, it creates a hard skeleton for itself out of calcium carbonate. That skeleton is left behind when the creature dies, and another polyp might create a new skeleton on top of it. The reef grows as this cycle continues. If conditions change and the growth of new polyps slows down, the reef will be considered damaged. If the growth of new polyps stops altogether, it is considered dead.
Natural Stressors
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Coral reefs are affected by natural and human factors. Natural stressors are occurrences such as hurricanes, typhoons, and plagues of predators that eat living coral. Natural stressors are usually temporary, and once they are over, a healthy coral reef will recover independently.
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Human-Induced Stressors
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Human-induced stressors are more lethal to coral because they are more consistent and longer in duration, according to the Global Coral Reef Alliance. Overfishing can remove fish that are vital to the ecosystem of the reef and anchors from the same fishermen can break off pieces of the reef. According to the GCRA, pollutants from industry and agriculture cause disease and tissue damage in polyps. Sediment from water runoff is thought to be a major culprit in destruction of reefs. Sediment deposits smother the organisms that are vital to the reef system, according to the GCRA.
Coral-Bleaching
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Warming of surface temperatures causes a condition that is known as coral-bleaching. As the name suggests, this gives the corals a white appearance as if they have been chemically bleached. No chemicals are involved in this process. Living reefs are covered with living organisms such as algae and other plants. Because reefs form in shallow water, an increase in the temperature can affect these organisms. When conditions become too hot, the organisms die. Clive Wilkinson, who published an executive summary of the status of coral reefs, cites the el nino of 1998 as a cause of coral bleaching.
Recovery
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GCRA provides several suggestions for the improvement of conditions for coral reefs. Fisherman can use alternate anchors, and employ methods that promote the reproduction of the fish they catch. Proper treatment of sewage and avoiding harmful fertilizers would reduce the risk of disease. Wilkinson also states that national and local governments need to pass stricter laws for the protection of coral reefs.
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References
- Photo Credit coral reef image by Christian Schoettler from Fotolia.com
