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Sunscreen Causes Coral Bleaching

Killing off an ecosystem because of the coconut-scented oils I have no choice but to slather on my body? When I read the report, I was nothing short of perplexed.

An Italian university study published in the April issue of Environmental Health Perspectives links sunscreen to coral bleaching. Coral is an aquatic, stone-like structure that has cracks and crevices inhabited by colorful symbiotic organisms called zooxanthanellae. Bleaching, induced by changing ocean temperatures, pollution, and bacterial pathogens, is the process in which hard coral loses its alluring tenants, leaving behind bare, whitish rock. While science has indicated sunscreens can bioaccumulate in the food chain, and that they may breakdown to form toxic by-products, never had there been a connection between my pina colada scented beach balm and coral bleaching.

The researchers tested, out in the wilds of the Atlantic, Indian, and Pacific Oceans as well as at the Red Sea, the effects of different sunscreen brands, protective factors, and concentrations on coral algae. They found that the ray blocking products caused the cells of algal organisms to rupture, resulting in death. Through a few steps of math, the scientists estimate that about 25 percent of the sunscreen we apply to ourselves is washed off during a 20 minute dunk, and that since around 10 percent of UV filters are used in tropical areas that contain coral, up to 6,000 tons of the stuff is released annually in reef areas. To me, that seems like more than enough sunscreen in the water.

Coral reefs are among the most biologically productive ecosystems in the world—and 60 percent of them are threatened by natural and anthropogenic forces. As someone who was on a course to be a marine scientist, I thought I had the eco-friendly ocean thing down pat: don’t throw trash in the sea, no soap bathing in the ocean, and no harming the fragile ecosystems. But sunscreen? And what about my other personal products: lotions, cosmetics, hair care, and face creams—are they killing coral, too? Am I just a walking coral reef time bomb? That’s to be determined, but in the meantime, sites like National Geographic’s Green Guide and others can lead you to biodegradable blocks that will help protect our reef-brethren.

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Molly Webster is the assistant editor at OnEarth magazine. She is also the science producer for The Takeaway, a radio production from Public Radio International, the New York Times, and the BBC that's causing a radio revolution. Works appear in Scien... READ MORE >