This past summer, I volunteered in Dr. Danielle Dixson’s marine science laboratory on the University of Delaware’s College of Earth, Ocean, and Environment Hugh R. Sharp Campus in Lewes, Delaware. The lab is studying how different types and concentrations of sunscreens affect the behavior and survival of horseshoe crab larvae. This study is important because horseshoe crabs, as a keystone species, are an integral part of the Delaware Bay. As a keystone species, horseshoe crabs are connected to every part of the ecosystem – even humans. Most famously, they are known for their unique blood and the large amounts of eggs they lay. These eggs become food for the red knot, a shorebird that loses much of its body weight as it flies non-stop from South America to Delaware’s shores, where it bulks up again for the second half of its journey to the Arctic. Horseshoe crab blood contains a special protein that acts as the crab’s immune system because it clots around micro bacteria. The protein is called limulus amebocyte lysate (LAL) and scientists have developed a way to utilize it for the benefit of humans. Everything that goes into the human body, such as needles, pacemakers, and hip replacements, is tested with LAL to ensure it has been properly sterilized.
We should examine how human activity affects the environment for practical purposes, such as ensuring we have access to LAL, as well as intrinsic purposes, such as ensuring the red knots have a means of survival. Ashley Barnett, a student working on the project, explains that, “The overlapping timing of the tourist season with horseshoe crab spawning aggregations [which is May through July] leaves the shallow sand-buried egg clutches exposed to a variety of anthropogenic pollutants, including sunscreen.” We have a responsibility to look at how we influence our environment and try to find a solution to the problems we create. As part of its work, the Dixson team is working to determine the sunscreen that causes the least amount of harm to horseshoe crab larvae. The team is still analyzing its data, so the results of the study are still unknown, but the team hopes to publish its work.