Photo: Person Snorkeling near a Coral Reef

by Michele McKay

The hottest season of the year is arriving in the Islands, and although school is starting, it doesn’t mean that swimming and surfing have stopped! As you head to the beach for a refreshing after-school or after-work session in the water, remember to use sunscreen – but be aware that although sunscreen helps to protect our skin from cancer, some formulations are far from helpful to the marine environment. A recent study reports that many brands contain chemicals that can seriously harm the very reefs we are attracted to for their beauty and their surf breaks. Sunscreen-induced bleaching threatens up to 10% of coral reefs worldwide, and although the amount one person uses may seem insignificant, it all adds up: researchers estimate that 4,000 to 6,000 tons of sunscreen wash off swimmers and into the sea annually.

The problem is complex, and it involves the symbiotic relationship between zooxanthellae algae and reef-building coral. Zooxanthellae live in the tissue of coral polyps, providing the coral with food energy from photosynthesis. Trouble begins when exposure to four sunscreen ingredients – paraben, cinnamate, benzophenone, and camphor derivative – awakens dormant viruses inside the zooxanthellae algae. The activated viruses begin to replicate, and their numbers increase until the algae bursts. Viruses spill out into the water, creating an epidemic by infecting and killing additional zooxanthellae. When zooxanthellae algae die, the coral reef bleaches and dies.

Roberto Danovaro, a researcher in marine sciences at the Polytechnic University of the Marche in Ancona, Italy, led a scientific team in studying the effects of sunscreen on coral reefs in the Pacific, Atlantic, and Indian Oceans. "Once the viral epidemic is started, it is not a problem of toxicity," Danovaro says, explaining the chain-reaction nature of the process. He and his team report that coral damage occurs even at low levels of exposure to sunscreen and that typical amounts used by swimmers can activate algae viruses and completely bleach coral in just four days.

What you can do:

  • Shop at Down to Earth. We offer a large selection of natural sunscreen products including some of the safest, most effective formulations on the market. These are a little bit more pricey compared to the basic formulations that we carry. But even the basic formulations that we carry, which are less expensive, are better for the environment and your health than sunscreens available in most stores. The wide variety gives customers choice depending on their needs. If you'd like help understanding the difference between the various options, our friendly and expert staff will be glad to help you find the right sunscreen for you.
  • Protect yourself with a UV-blocking shirt to reduce the need for sunscreen.
  • Evaluate your sunscreen at Skin Deep, an online safety guide to personal care products from the Environmental Working Group:
  • Learn more from the Danovaro paper, “Sunscreens Cause Coral Bleaching by Promoting Viral Infections” published by the online journal Environmental Health Perspectives at