Snorkellers alert: Synthetic chemicals in sunscreens are bleaching coral reefs, 60 percent of which are threatened worldwide. One simple way to help is to cover up with UV blocking swimwear rather than sunscreens that cause "rapid and complete bleaching of hard corals, even at extremely low concentrations," according to an Italian study published earlier this year. Researchers lightly coated their hands with sunscreens containing benzophenone-3, octinoxate, methyl cinnamate, parabens and propylene glycol, and immersed them in seawater tanks containing coral from the Atlantic, Pacific and Indian oceans, and the Red Sea. The chemicals made zooxanthellae, which live in symbiosis with coral polyps, vulnerable to viral infection.

If you're going to spend an hour or more in tropical waters, befriend coral by showering sun block from your body (for faces and hands, see better sunscreen links below) and putting on sun-blocking swim and surf wear that bear Ultraviolet Protection Factor (UPF) ratings from the Skin Cancer Foundation of 30 and up. These tightly woven fabrics will also give you a break from these potentially hormone-disrupting and carcinogenic chemicals. "Because sunscreens are lipophylic," the researchers write, meaning they collect in animal fats, "they can bioaccumulate in aquatic animals." Benzophenone-3 and octinoxate have been found in our bodies, as well. 

Here are some UV screening shirts. All the companies below have 'em for men, women and kids.  In these bright second skins, you'll be in the swim with the rest of the color on the reef.

* Patagonia's 30 UPF rash guards get top green points with 84 percent recycled poly. We love the hooded long sleever with back zip pocket.

* Body Glove's 50 UPF shirts and classic O'Neill 50-UPF offerings, including a nifty pair of short-shorts, are at the serious surf site RashguardShirtCo.

In the water and out, Xcel's Hawaii-bred 50-UPF guards come with Island floral accents or in solids, including a pair of knee-length men's shorts. Find dealers in your zip code at Xcelwetsuits.com.

Solarweave makes chlorine-resistant UPF 50 Lycra shirts in stunning fuchsia (the better for lifeguards to see you with); unisex swim shorts and tights, and baby jumpsuits.

Note: If UPF clothing is stretched taut, it loses effectiveness, so get a comfy fit.

For more about these chemicals, and alternative natural mineral sunscreens that are least toxic to you and coral reefs, click here.

This article originally appeared in Plenty in July 2008. The story was added to MNN.com.

Copyright Environ Press 2008