Coral Catastrophe


Courtesy of the Ocean Agency

A Thriving Coral Reef in Alor, Indonesia; this is what humans have the potential to maintain by working to mitigate climate change.

Violet Perloff, Science and Technology Middle School Writer

Resting on top of the boat, the turtle looks around. As he moves his flipper, an octopus appears and then changes color. The water, penetrated by the light, creates an aquarium-like environment with brilliant corals and rainbow fish. As the sky blue water moves with the current, a piece of dead coral floats by, ruining the picturesque scene, representing the grim future ahead if nothing is done: white coral; no fish. The turtle relies on healthy corals to provide food, but his world is dying. He is only thirteen, with about 30 years left in his life, but the quality of his life is decreasing each year. 

When coral is under stress, it bleaches. All of the species that rely on the reef directly quickly decrease in population. For example, butterflyfish’s larva settles on live coral and 80% of their diet is coral polyps.  Snappers eat butterflyfish. If the butterflyfish cannot reproduce and lose their main source of food, the snappers would suffer the same fate. All of the species that indirectly rely on the reef decrease in population as well. These losses hurt many – the fish, the people who live near reefs, and anyone who has a job that is based on fishing or the ocean. Hope, however, is not lost. Bleaching isn’t permanent. If the water returns to its original temperature and health, the coral can regain color and sea creatures might even make a fruitful come back. 

Polyps create most of the structure for the corals. At night, they feed on small particles, mostly plankton. Polyps maintain homeostasis. The polyps host the zooxanthellae. Zooxanthellae, which is a type of algae, gives coral its color. The coral supports the algae by giving it all of the necessary components for photosynthesis. The algae give the oxygen to the coral, creating a symbiotic, mutualistic relationship. The coral uses all the products of photosynthesis to grow. This very beneficial growth system can only be sustained between 77º F and 84º F waters. When this process is disrupted by ocean temperatures, coral bleaching occurs. The coral becomes stressed. Coral expels the zooxanthellae, losing access to both its source of oxygen and color. When this happens, it leaves behind a morbid, white skeleton. 

Corals have four stages of health. There is healthy coral, fluorescing coral, bleached coral, and dead coral. A healthy coral can provide food and shelter for many different aquatic animals. It is strong and maintains its original color. Fluorescing coral looks as though it has been placed under black light. It is objectively beautiful but it is dying. Bleached coral is white. It is weak and does not provide animals with a food source. Dead coral is just as one might expect – it is brown, leaving no trace of its once vibrant colors. If there is a large amount in one area, it tends to smell, just like other dead organisms. As more corals start to die or bleach, fluorescing and bleached corals are still revivable. If the water temperatures return to normal and the coral is given enough time to recover, ranging from ten to fifteen years, the coral can return to its original health.

Coral provides food and shelter for many aquatic animals. When coral bleaches, the animals that rely mostly on coral will leave or die off quickly. This affects the animals farther up the food chain, leading to a loss of biodiversity, which is the sign of a healthy ecosystem. 

The ocean and the fish are not the only ones affected by coral bleaching. Many ocean-side communities rely heavily on fishing and are greatly impacted as well. When coral bleaching occurs, fish go away. When fish go away, it is harder to fish for a living and sustain an island. Coral reefs also provide us with many other essential products. One main construction material, limestone, comes from coral reefs. Lots of new cancer treatments are coming from coral. Tourists also come from near and far to see large coral reefs. It is estimated that coral reefs contribute 375 billion dollars to the global economy every year. According to Columbia University, reefs provide food and resources for more than 500 million people in more than 100 countries. Therefore, their importance to our environment – whether that be under the sea or that of those walking the Earth around us – is undeniable.

Coral bleaching is caused by warmer water temperatures, which is related to global warming and climate change. According to Carbon Brief, a news site that addresses climate issues,  severe bleaching events have become five times more frequent since the 1980s. In the 1980s, coral reefs were affected by bleaching about once every twenty-five to thirty years. This gave the reefs enough time to recover. Now, reefs are being affected every three to five years, giving reefs one-sixth of the time to recover. In 2016, the worst bleaching event was recorded. Combined with climate change and El Niño, a natural event that occurs when ocean water gets warmer, 75% of all reefs in the world were affected according to Carbon Brief. Coral bleaching has been happening for a long time but it has gotten a lot worse progressively. Columbia University says that only 15% of coral will have enough nutrients to continue growing beyond 2050.

There are many solutions that could help this situation. Some larger-scale solutions are being worked on, but something still needs to be done in the short term. The Paris Agreement is supposed to limit the rise of ocean temperatures to 1.5ºC, but that will still greatly damage coral reefs.  Other leaders in the global community are working to create something that expels greenhouse gasses from the atmosphere. As climate change is very closely related to coral bleaching, ordinary people need to use cleaner energy and renewable resources in order to mitigate the rise of ocean temperatures. Although many have hopes to slow and possibly reverse climate change, some scientists have discovered corals that withstand warmer and more acidic waters. These corals can be referred to as “super corals.” The super corals were found in Kāne’ohe Bay off the coast of Hawaii. This bay was devastated by coral bleaching, to a point that scientists believed was beyond repair. The super corals adapted, however, and came back. Scientists are now trying to find other adapted corals so that they can save reefs all over the world. 

Coral bleaching may not be as well-known as other side effects of climate change but it is just as important. Some may think that coral bleaching does not affect us, but coral reefs provide us with many resources that we depend on. Many treatments for cancer, heart disease, and even Alziehmers come from coral reefs. The National Oceanic and Atmospheric Administration, more commonly known as the NOAA, says that 500 million people rely on coral reefs for food, income, and protection. According to the World Wildlife Fund, if properly managed, a reef can provide just over 16 tons of fish each year.  Ms. Caitlin Norton, a WFS Biology teacher says: “People don’t realize how much we depend on our natural resources until they start to degrade ….” Clearly, we must protect our coral reefs, before the effects of their depletion become indomitable forces in our global environments.