Coral Reefs Essay

Submitted By AshLee1238
Words: 966
Pages: 4

There are over 4,000 different varieties of fish and aquatic animals that rely on Coral reefs as their primary source of housing and protection. However, it has been reported that large numbers of the coral reef population has been completely destroyed in the past years through a process called coral bleaching. It has also been said that humans may have contributed to the destruction of the Earth's coral reefs both indirectly and directly. Without coral reefs, these fish will be left homeless and the chances of survival for them will decrease dramatically.

Coral reefs consists of communities of organisms called coral. Coral is an animal belonging to the phylum Cnidaria, which is produced by living organisms (Wikipedia 2009). Corals are composed of structured called polyps. Each individual polyp is responsible for each bump in the reef. The exoskeleton on these animals is a result of the actual polyp secreting calcium carbonate (Wikipedia 2009). Coral reefs can take a variety of different shapes and forms including Fringing, Barrier, Patch, Apron, Bank, Ribbon, Atoll, and Table reef (Wikipedia 2009). These specific types of reefs all differ in shape, size, location and position. However, they are all similar in their location where they are situated on the Earth. Coral reefs are located in tropical oceans near the equator (Missouri Botanical Garden 2002). The Great Barrier Reef in Australia is where the largest coral reef in the world is located. As mentioned previously, large numbers of aquatic animals call these coral reefs home, and a place for protection. In addition to providing housing for these animals, coral reefs are also great ecosystem engineers in the way that they also provide nutritional support for the animals. Animals feed either on small animals living near the coral, or on the coral itself. These aquatic organisms that depend of coral reefs include many different species of fish, jellyfish, worms, shrimp, lobsters, crabs, molluscs, starfish, sea urchins and sea cucumbers (Wikipedia 2009). However, a process called coral bleaching has damaged and killed large amounts of the world’s reefs. Corals have a symbiotic relationship with unicellular algae called zooxanthellae that live within their tissues (Wikipedia 2009). Coral reefs get their color and food from the zooxanthellae. When corals become stressed they go through a process in which the coral expels the algal cells. Their beautiful coloring is then loss and the coral begin to appear white. This is where the term “bleaching” derived. The corals receive their coloration from the zooxanthellae living within their tissues (Bucheim 1998). Once the coral becomes stressed and bleaching begins, it is possible that it will continue to bleach even if the stressed-inducer does not persist anymore. If zooxanthellae populations do not recover, the coral reef eventually dies. On the other hand, if the bleaching is not too severe the affected corals could regain their symbiotic algae within several weeks or a few months (Bucheim 1998). Reasoning behind what makes corals become stressed has been hypothesized. It has been said that humans are a result of some of the stress-induced events. Rising and lowering of water temperatures are the largest known cause of coral bleaching. When heated above their maximum temperature thresholds corals become stressed resulting in coral bleaching (Goreau 2005). An increase of just 1.8 degrees Fahrenheit above the typical maximum summer temperature can cause corals to expel their algae (Rod 2003). Changing sea surface temperatures have been linked to climate change and global warming. Global warming caused by the green house effect has raised the temperature of the oceans so high that corals become stressed and expel or damage the zooxanthellae living within their tissues (Ocean World 2004). This would be an example of an indirect way that humans are harming the coral reef population.

A direct human