Coral Bleaching: Loss of Color, Loss of Life

Somewhere in Australia’s Great Barrier Reef, a yellow fish just emerged behind a bright pink coral. A nearby black-tipped reef shark (with a remora under its belly) chases a school of bright blue fish as a jet-black stonefish hides in the sand below and an orange scorpionfish swims amidst the chaos. Somewhere else though, the reef lies barren, with white coral parched under the hot Australian sun and the few fish living there starving with little oxygen. No fish, no sharks, no color—in their place lies a desolate wasteland where a beautiful ecosystem once thrived. 

Coral reefs attain their beautiful color, not from coral tissue, but the algae living within it that help process oxygen and create compounds for energy. Coral bleaching occurs when algae densities decline or their photosynthetic pigments disappear, and if color cannot return (i.e. if algae population or pigmentation cannot recover), the corals die. Usually, coral whitens because algae cannot function properly at abnormally hot temperatures. Amidst global climate change combined with other humanmade threats like overexploitation, overfishing and nutrient overloading, algae within coral cannot cope with rising temperatures in the ocean. Surveys of the aforementioned Great Barrier Reef suggested that more than a third of its corals had died by 2015. While reefs occupy just 1 percent of the world’s marine environment, nearly 25 percent of marine species live in reefs. In other words, among the most destructive impending ecological disasters will occur beneath the waves as climate change and coral bleaching intensifies in the next decades. 

So why are healthy coral reefs so important, and how could coral bleaching affect human communities? 

Healthy coral reefs use rough surfaces and complex structures of coral, fish, and anemones to dissipate waves and buffer shorelines from currents and storm surges, which helps reduce the loss of life and property damage during natural disasters. Reefs also protect and shelter fish, which in turn provide food for over a billion people worldwide. Certain species like sponges produce chemical compounds that can help develop new medicines that can treat cancer, heart disease, and other diseases for which medicine is otherwise difficult to access. Many tourists explicitly seek out reefs to witness their raw beauty. Through fisheries, pharmaceuticals, and tourism, estimates show coral reefs provide a global $29.8 billion net benefit while potentially offering food and medicine to underprivileged areas. If corals die, fish disappear from the area, destroying the ecosystem and diminishing potential for fishing and medical research—and the several million people living in U.S. coastal areas near coral reefs would lack an essential buffer to intense storm surges and tropical storms. 

Despite the alarming acceleration of the bleaching crises this decade, we can learn successful means of countering environmental destruction from an unexpected source: Belize. In 2009, the Belize Barrier Reef Reserve System (the world’s second largest behind Australia’s) faced bleaching due to offshore drilling, rapidly deteriorating mangrove forests and intensified coastal development so severe that UNESCO added it to its list of most endangered world heritage sites. Belize’s Supreme Court ruled oil contracts illegal and its government later banned offshore drilling altogether. Mangrove-cutting faced strict regulations, the government heavily restricted fishing of sensitive species and plans to ban all single-use plastics. UNESCO removed the reef from its list, surveys of the reef note greater concentrations of live coral and herbivorous fish, and a country with a GDP of $8,300 per capita proved that coral reefs could recover from certain death. Although not completely regenerated, the once seemingly imminent doom facing Belize’s coast is now distant and unrealistic.

Among the most destructive impending ecological disasters will occur beneath the waves as climate change and coral discoloration intensify in the next decades.

Political opponents of such measures, however, spin success stories like Belize into issues of public health and security. For example, in 2019 city leaders in Key West, Florida banned the sale of certain sunscreens deemed chemically harmful to coral in the Great Florida Reef (the world’s fourth-largest reef system). Republican politicians framed Key West leaders as instigating high rates of skin cancer and discouraging use of sunscreen—they ignored that locals have hundreds of sunscreen options without the banned ingredients. Even in Belize, Conservative backlash against environmental laws highlighted that it harmed small fishermen and lacked effective enforcement—again, narratives emerge to unjustifiably declare mutual benefit for the environment and fisheries unattainable. In reality, while Belize’s reef recovered, fish stocks remained stable.  Opposing interests will always frame environmental benefit as offsetting potential public goods—in protecting coral reefs, though, society can improve the environment without significant public harms. 

But amidst the numbers and logic behind most environmental policies, coral reefs represent not only significant ecological and economic potential but awe-inspiring natural wonders whose fragility underscores their serene beauty and impressive organization. A healthy, colorful coral reef—with its bright reds, blues, yellows, and greens—should inspire us more than a dull white reef devoid of life can discourage us.