Sunscreen: A Hazard to Horseshoe Crabs

heatherlotsofhscYou might want to think twice about lathering up with just any old SPF sunscreen when you head to the beach this year.

According to an article written  in The News Journal by Molly Murray back in March, common sunscreens that contain a chemical called oxybenzone may be responsible for lowered numbers of horseshoe crabs in the Delmarva region. Murray interviewed Danielle Dixson, an assistant professor at the University of Delaware College of Earth, Ocean and the Environment, who has been studying the effects of oxybenzone on horseshoe crab eggs and larvae, and the results were obvious. According to Murray’s article, the larvae that were exposed to a seawater-sunscreen solution “became sluggish and barely moved while the crabs in regular sea water were much more active.” Dixson reported that during trials, the sunscreen had a major effect on survival rates of the eggs, so much so that many never even hatched.

Why This Matters:

Horseshoe crab eggs

Not only are horseshoe crabs ancient and fascinating sea creatures that populate our shorelines, but their eggs provide critical sustenance for those beautiful migrating birds that layover in the Delmarva region this time of year. Birds from Central and South America, such as the red knot or the sanderling, time their pit stops in our area specifically during horseshoe crab breeding season in order to fuel up on eggs before heading north to the Arctic to breed. A decline in horseshoe crab eggs turning into horseshoe crabs could ultimately mean a decline in our vast array of migratory birds to our area.

What You Can Do:

When purchasing sunscreen, look for brands that contain avobenzone instead of oxybenzone, although testing of the effects of avobenzone are still very limited too. Better yet, choose a sunscreen with zinc oxide, natural mineral found on the earth’s crust that blocks UVA, UVB, and UVC rays. Also, avoid using spray sunscreens as they can increase the amount of sunscreen that lands on our sandy shores.

For more information read Molly’s full article, entitled Sunscreen May Harm Horseshoe Crabs. Check out the Environmental Working Group’s 2017 Guide to Sunscreens for environmentally safe options for playing out in the sun this summer.

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