Toxic for reefs

As of January next year, visitors to Palau, an island country in the western Pacific, will be prohibited from buying or using a range of sunscreens. The country has classified products containing any of 10 commonly used sun filters and preservatives as “reef-toxic”, as they are thought to harm coral reefs. Other places have followed suit, and similar bans will come into effect in 2021 in Hawaii and in Key West, Florida.

Craig Downs at Haereticus Environmental Laboratory in Virginia and his colleagues ran laboratory experiments to assess the problem. They found that immature corals exposed to oxybenzone, an ingredient that is commonly used in sunscreens, die.

The corals became deformed and pale in colour, and were unable to eat, as depicted in the images above. “Their mouths just opened, and it looked like a horror movie scream,” says Downs. “They were as good as dead in the first 8 hours.”

Sunscreen manufacturers have said that lab-based experiments can’t tell us what happens in the real world, but more bans are likely. “We have one reef, and we have to do one small thing to protect that,” Teri Johnston, mayor of Key West, was quoted as saying before the city’s vote on sunscreen. “It’s our obligation.”.  (Jessica Hamzelou, New Scientist Aug 2019)

But if you don’t use sunscreen you can get cancer.  Damned if you do, damned if you don’t.  And the warming oceans are destroying the reefs in any case.

Tomorrow: problems for humans using sunscreens. And then I will try to find something cheering to talk about!