Summer is in full swing. With temperatures at their peak and beach vacations underway, most of us have probably stocked up on sunscreen. We slather it on children to prevent painful burns and apply it to ourselves to avert skin cancer. But as much as sunscreen protects our skin from harm, it can do just the opposite to coral reefs.
Researchers have found when sunscreen washes off beach-goers into the ocean, it can cause coral bleaching. The problem is significant. Some 4,000 to 6,000 metric tons of sunscreen wash off of ocean swimmers each year, with impacts concentrated in tourist-favored areas.
A handful of chemicals are thought to be behind the problem, among them: parabens, cinnamate, benzophenone, oxybenzone, and camphor derivatives. These chemicals can awaken dormant viruses that cause corals to expel symbiotic algae. Without algae, corals lose their vibrant color, turn white, and eventually die. Benzophenone has also been found to suppress coral recruitment – effectively killing off coral babies.
Coral reefs are already under duress, thanks to climate change, pollution, and overfishing. The last thing they need is another threat, especially one that can be remedied. We cannot – and should not – stop using sunscreen, but we can choose products that pose less of a risk to coral when we are in vulnerable areas.
Physical sunscreens are one option; the other is eco-friendly chemical sunscreens made without the offending ingredients. Choosing such products also means minimizing the harmful chemicals we apply to our skin, so it’s a win-win.
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Web Links
Toxicological effects of the sunscreen UV filter, benzophenone-2, on planulae and in vitro cells of the coral, Stylophora pistillata
Sunscreen Chemical Threatens Coral Reefs
Photo, posted February 13, 2011, courtesy of Tim Sackton via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio, with script contribution from the Cary Institute of Ecosystem Studies.