Blog Contest Winner — Coral Bleaching

This article is a part of a series of posts submitted by students from around the world who are passionate about environmental sustainability. This article, specifically, comes from Angelina Reyes and was created on March 14, 2018.

Published: Dec 26, 2020

Coral Bleaching

Imagine a lush forest teeming with thousands of species of animals, living symbiotically with the flora. Stretching 1,430 miles, it is approximately three times the length of the state of Michigan. Millions of people depend on it as a food source and the industries created from the ecosystem earn billions of dollars for the country’s economy. In recent years, however, global climate change has initiated a vicious cycle in which the thousands of species of trees die at unprecedented rates. Without a home, animals must relocate or otherwise perish, either way leaving a barren wasteland in their wake. In fact, this phenomenon has transpired for more than 20 years, but has instead taken place in the underwater equivalent of a forest: coral reefs.

From the Great Barrier Reef on the coast of Australia to the small bundles of coral in Florida, these catastrophes occur so frequently that the ecosystem barely has a chance to rebound before the next mortality event. The Smithsonian Ocean Portal Team reports that coral reefs in the United States have an estimated value of $172 billion every year, supplying food, protection, jobs, and medicines for those that depend on it. With half a billion people at risk for losing their source of food or income — according to Michael Slezak’s article from The Guardian — , the real question is why this issue hasn’t caused an international outcry.

The contrast between healthy (left) and bleached (right) coral is evident from the unnatural white coloring, a sign of disaster to come. Photo from Smithsonian National Zoo.

In order to understand how to solve this problem, one should understand the underlying root of bleaching. The Smithsonian Ocean Portal Team claims that a rise of even 2 degrees Fahrenheit above the normal sea temperature will cause coral bleaching. Although this seems like a minute change, Richard Vevers, founder of The Ocean Agency, explains the significance of 2 degrees by comparing it to human conditions in the Netflix documentary Chasing Coral. “Imagine your body temperature rises one-degree centigrade or two degrees centigrade. Over a period of time, that would be fatal,” Vevers says.

After this initial stressor, the symbiotic algae that act as an internal energy source for the coral are expelled from the coral animal, according to Slezak. This diaspora of photosynthetic organisms results in the coral losing its color. In Chasing Coral, Dr. Ruth Gates, director of the Hawaii Institute of Marine Biology, likens bleaching to a fever for humans, calling it a “stress response”. Without their primary source of food, the likelihood of mortality increases considerably.

On the other hand, life is known for being resilient, and coral is not an exception. In the last few years, corals of unnaturally vibrant colors have been observed in bleaching reefs. Jörg Wiedenmann and Cecilia D’Angelo from the Coral Reef Laboratory of the University of Southampton have determined the reason behind this anomaly. They describe the corals’ fluorescence as a mechanism to fight against harmful extreme sunlight: “some corals increase the production of colourful protein pigments when they are exposed to more intense sunlight. Humans get a sun tan — corals become more colourful.”

An Acroporid coral colony begins to bleach, attempting to survive with its blue sunscreen-like pigmenting. Photo from the ARC Centre of Excellence for Coral Reef Studies.

Fortunately, people have noticed the coral bleaching and are demanding change. Numerous organizations and initiatives have been created in order to combat the plague of coral bleaching. There are countless ways to support the efforts, whether you live on the coast of Florida or in icy Michigan. Nature Conservancy lists several ways for people of all ages to contribute: conserving water to decrease water pollution, walking or riding a bike to reduce the air pollution that warms the Earth’s atmosphere and oceans, using coral-friendly gardening products, or even spending a vacation volunteering at a reef clean-up event. The Chasing Coral team also suggests many ways to help spread the word of this pandemic through their documentary as well as social media.

People may mistake the unnaturally white appearance of bleached coral as a beautiful rare genetic mutation. However, Vever emphasizes the need to realize that, rather than a display of the exotic diversity of nature, the coral is desperately calling for help, saying, “Look at me. Please, notice.” In order to save these amazing organisms and the aquatic life that they support, everyone needs to respond. Next time you notice the corals, answer their call.

For more information on how coral reefs are being harmed by everyday consumer products, such as sunscreen, click here.

This blog was submitted to the Greening Forward Blog Competition by Angelina Reyes and selected as one of the winning posts.

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