Sunscreen vs. Coral

This summer, millions of people will put on sunscreen at the beach. Sunscreen is important. It protects skin from getting damaged by the sun. But scientists recently found that many sunscreens contain chemicals that kill coral reefs. Some seaside spots are banning sunscreens that have these harmful chemicals.

Corals look like plants, but they’re actually tiny animals that live in groups. They live at the bottom of warm, shallow ocean water. Their hard skeletons form reefs, which provide food and shelter for ocean animals. Healthy coral reefs are colorful and full of life. However, many reefs around the world are struggling.

Biologist Craig Downs says that sunscreens are hurting reefs. A few years ago, Downs began studying dying reefs in the Virgin Islands, in the Caribbean Sea. A local man overheard him talking about the problem. He suggested that Downs investigate sunscreen.

Beaches in the Virgin Islands receive thousands of visitors every day. Each evening after tourists left the beaches, locals saw sunscreen floating on the ocean’s surface. It had washed off people’s skin while they were swimming.

Downs’s team tested the seawater. They found large amounts of a sunscreen ingredient called oxybenzone (ahk-see-BEN-zohn). In their lab, they exposed coral larvae to the chemical. After a few hours, the baby corals’ bodies changed shape. Their mouths didn’t develop normally. They started sealing themselves in hard skeletons and died.

Oxybenzone also made the young corals bleach. This means the algae that live inside the corals and give them nutrients died. The corals lost their color and energy. In the wild, bleached corals often do not survive. “It was horrific,” says Downs.

Downs’s findings made headlines. Many local, state, and national governments began taking action. Last year, Hawaii, the country of Palau, and several Caribbean islands passed laws banning sunscreens containing oxybenzone and octinoxate (ahk-TIN-ahk-sayt). Both of these chemicals were found to damage corals. Hawaii’s ban will go into effect in 2021.

Even though some sunscreens hurt corals, it’s still important to protect your skin from the sun (see How Sunscreen Works). People can cover up with clothing. They can also choose sunscreens that contain minerals like zinc oxide and titanium dioxide. These ingredients help protect people from the sun and are safer for ocean life.

“When we reduce sunscreen pollution,” says Downs, “we can help corals have a chance to recover.”