Rising Temperatures and the Destruction of Coral Reefs

It is a well-known fact that climate change has been drastically affecting a number of ecosystems around us; however, one of the most negatively affected ecosystems isn’t found here on land, but rather in large bodies of water known as oceans. While a number of species are meeting their demise as a result of increased plastic levels, others are being starved to death by the increase in ocean temperature and acidification. One particular species that has been largely impacted by global warming is coral. Coral, a member of both the animal and algae family, can be found in both “shallow, tropical seas and the cold, dark depths of the oceans” (NOAA). Coral are also known to have a symbiotic relationship with a small alga known as zooxanthellae. These tiny photosynthetic organisms produce carbohydrates, the main source of energy for the coral. However, with the increased acidification in the oceans, the “shell” of the coral begins to break down, causing the zooxanthellae to either die or migrate out of the coral, leaving it with no way of obtaining the amount of energy it needs to get a sufficient amount of food. According to the National Oceanic and Atmospheric Administration, coral reefs are built by animals known as coral polyps. These animals can be found in “a number of forms, [such as] large reef building colonies, graceful, flowing fans, and even small, solitary organisms” (NOAA).

Coral reefs are vital for a number of organisms because of their variety. For instance, the coral reefs that are closer to the surface, provide shelter for small fish and allow them to raise their young in a safe environment away from predators. In addition, coral reef ecosystems help “protect coastlines from storms and erosion, provide jobs for local communities, and offer opportunities for recreation” (NOAA). However, “human activities alter the natural disturbance regimes of coral reefs by introducing new chronic stressors” (Nystrom, M. et al.). One of the major stressors that corals face are the rising ocean temperatures. According to the Journal of Experimental Marine Biology and Ecology, “the temperature variations disturb the complex relationship between host and endosymbiont” (Tunala, L. et al.). In addition to the rise in ocean temperatures, we also begin to see a rise in ocean acidification levels and an increase in storm intensity. These powerful storms can create physical damage to the corals, resulting in a wide event known as coral bleaching. The recent “bleaching events are [considered] the first biological indication of global warming” (Glynn, PW).

Another stressor coral is facing is the rise of ocean acidification. The rise in pH levels is causing the breakdown of Calcium Carbonate, an important compound needed by coral. Without Calcium Carbonate, “reef-building corals may exhibit several responses to reduced calcification, all of which have deleterious consequences for reef ecosystems” (Hoegh-Guldberg, O. et al.). Despite the number of stressors corals are faced with, scientists are now being led to believe that the dramatic increase of CO2 is the primary cause of increased temperatures in Earth’s atmosphere. As a result of the increased CO2 levels, scientists are now finding that the excess CO2 “currently enters the ocean, where it [then] reacts with water to produce carbonic acid, [which, in turn, causes a decrease] of marine organisms such as reef-building corals” (Hoegh-Guldberg, O. et al.).

Overall, with the dramatic increase of global warming at hand and the destruction of the Earth’s coral reefs, citizens are beginning to become concerned. However, with only a few simple steps, people can start reducing their carbon footprint. Recycling, carpooling, and using reusable bags are just a few small ways a single person can make a large difference. Even though it may seem like not much of a difference is being made, each time someone recycles, they keep one more bottle out of the ocean and together, we can help save the coral reefs.