The benefits of coral have been listed by Carte (1996). At the outset they are excellent sources of income because of their tourist attraction, with thousands of tourists visiting the Great Barrier Reef for scuba diving. The coral reef ecosystems are also invaluable in providing a fertile environment within which fish are able to thrive. as a result, fisheries are associated with coral reef systems and generate a considerable amount of wealth for Australia. Since there is such an abundance of fish thriving in the coral reefs, they also provide a source of protein for poorer countries through a diversion of supplies to those countries (Bryant et al, 1998). Thirdly, coral reefs are also effective in protecting coastlines from erosion, flooding and damages caused due to storms, because they function as a barrier to wave action.
Rising temperatures have a detrimental impact upon coral because they cause bleaching. when the thermal tolerance level of the corals is exceeded, then there is a corresponding explosion in their composition of photosynthetic symbionts or zooxanthellae, which in turn leads to bleaching (Hoegh-Guldberg, 1999). When the corals are bleached white, it means that their zooxanthellae are destroyed, thereby damaging this life form. Bleaching is associated with coral mortality, with the intensity of temperatures, corals such as pocillopora, staghorn corals or Acroporidae, Acropora Hyacinthus and Acropora gemmifera have disappeared, and Hoegh-Guldberg (1999) estimate that several species of coral which are 700 years old have died out due to bleaching, although corals are capable of surviving almost up to 1000 years. . . .In general, corals are able to respond to natural variations in climate through the processes of acclimatization or modifying the cellular metabolic processes in such a manner that they are able to function at different temperatures.
In general, corals are able to respond to natural variations