Threats To Coral Reefs Environmental Sciences Essay

Coral reefs deal with many threats, from both nature and man. Coral reefs have become the home for over twenty five percent of the marine life in the ocean and they’re the largest living structures on earth (Coral Reefs and CO2). Also, reefs provide food for about 500 million people around the world (Connor). Coral reefs require balanced water chemistry for growth as well as balanced light, temperature, and nutrient levels. Any changes to these can affect the survival of the coral and potentially kill them (Sandhyarani). Ten percent of the tropical reefs in the world have already been lost and the reefs that remain show signs of deterioration and possible loss (Coral Reefs and CO2). “Twenty percent of the worlds reefs have been destroyed and show no immediate prospects of recovery,” Clive Wilkinson, World Wildlife Fund. The two main threats that reefs deal with come from humans (anthropogenic) and natural events.

Consequently, global warming may now have the most devastating affect on coral reefs from humans. Global warming can be caused by the release of CO2 into the atmosphere as a result of the burning of fossil fuels (Coral Reefs in Danger). An increase in ocean temperature is a direct affect of global warming and extremely dangerous to corals and the organisms that call the coral home. The warming can cause coral bleaching, when coral polyps drop the algae that live on them leaving behind the bright white color of the coral’s skeleton (Thompson). This algae provides the coral with eighty percent of its energy, making the algae critical to the coral’s existence (Threats). Coral life depends on algae, but too much can also have a negative effect. Pollution has become one of the leading human threats to coral, resulting from runoff, sewage, oils, chemicals, fertilizers, and radioactive wastes getting into the ocean (Kaku). These chemicals can increase the nutrient levels in the ocean waters and cause algae blooms and growth of other marine organisms that can compete with coral for space. Pollution can also lead to light deprivation and will ultimately starve a coral, which depends upon its symbiotic algae to produce food photosynthetically (NOAA CoRIS). Pollution can be linked to coral diseases as well; due to the poor water quality that pollution produces. If an oil spill occurs coral spawning, the oil can destroy the egg and sperm of the coral polyp as it floats near the surface before it can ever fertilize and settle (NOAA). Destructive fishing methods are another human related threat to coral reefs. Blast fishing, the most destructive to reefs, kills not only the objective fish but also reef animals and the reefs themselves (Thompson). Cyanide fishing, which involves the release of cyanide into the ocean to stun fish, can kill the coral polyps and corrupt the entire reef (NOAA). Coral mining can also be extremely devastating for corals, the coral is mainly used for construction purposes and can be obtained fifty percent cheaper than rock from a quarry (NOAA).

Furthermore, natural threats are also dangerous the coral reefs. Coral diseases are the most common natural threat. Diseases can be caused by humans but they mainly derive from natural biological stresses such as bacteria, fungi, and viruses. They can also occur as a result of non-biological stresses such as increased sea surface temperature or ultraviolet radiation (NOAA). Nevertheless, they have the same impact no matter the cause and the main diseases include black band disease, white band disease, white plague, and white pox. Slowly over time, these progress to expand across the coral eating away at the coral’s tissue and leaving behind its white skeleton unprotected (NOAA). The waves that result from hurricanes and cyclones can break apart branches of coral and coral heads, scattering the fragments and leaving no chance for the coral to recover (McGinley). Tidal emersions, which leave corals exposed for long periods of time during low tide, can cause the coral to overheat and dry out the essential coral tissues (NOAA). Predation from fish, marine worms, barnacles, crabs, snails, and starfish can destroy reefs in some cases by eating the soft tissues of coral polyps (NOAA). Humans remain the largest threat to coral survival but natural events can still be devastative.

“Pollution, overfishing, and overuse have put many of our unique reefs at risk. Their disappearance would destroy the habitat of countless species. It would unravel the web of marine life that holds the potential for new chemicals, new medicines, unlocking new mysteries. It would have a devastating effect on the coastal communities from Cairns to Key West, Florida — communities whose livelihood depends upon the reefs.”–President Bill Clinton