Sunscreen might prevent a bad burn, but it might also be burning coral reefs, National Geographic reports. Four chemicals found in common lotions awaken viruses in algae living in coral, a new study finds; the algae then explode and can leave the reef without its food supply—causing it to turn white and die.
With up to 6,000 tons of sunscreen washing into oceans, scientists are at odds over how much is harmful to reefs. One expert said tests don't take into account quick dilution that would occur in the ocean; the author argues it doesn’t matter. "It's more like on-off,” he said. “Once the viral epidemic is started, it's not a problem of toxicity."