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Up to 6,000 tons of sunscreen wash off of ocean swimmers each year, posing a threat to up to 10 percent of global coral reefs, according to a new study in the journal Environmental Health Perspectives. Four common sunscreen chemicals can awaken dormant viruses in coral-dwelling algae, with results of horror-movie proportions: the viruses replicate to the point that the algae explode, spilling the viruses into surrounding seawater and infecting neighboring coral populations. The algae, called zooxanthellae, provide coral with food energy and contribute to reefs’ bright colors; without zooxanthellae, the coral bleach and die. So burn, baby, burn — or, better yet, seek out a nontoxic sun lotion.

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