Most Sunscreens Can Harm Coral Reefs. What Should Travelers Do?

FILE — Kali Gough, left, and Allie Harris, center, apply sunscreen as they prepare to lay out at Siesta Public Beach in Sarasota, Fla., June 14, 2011. Avoiding non-biodegradable sunscreen may be the one solution to coral bleaching travelers have the most immediate and direct influence over. (Chip Litherland/The New York Times)