Research that counts for horseshoe crabs

Imagine you are 17 years old and have just graduated from high school. You are standing before Delaware’s House of Representatives, trying to make your voice heard on an issue about which you are passionate.

Three years ago, Abigail Bradley, currently a senior in the Science and Engineering Scholars Program at UD, found herself in just that position. She was there to deliver a speech to the legislators urging them to declare the horseshoe crab the state’s official marine animal.

“It was a good experience but a little bit intimidating,” Bradley, who is majoring in biology with a concentration in ecology and organismic biology, says. “Everyone was really nice, though, and the bill ended up getting a unanimous vote.”

Her interest in the horseshoe crab and marine ecology began several years earlier, while she was in junior high. She had attended the University’s Coast Day, which celebrates research at the College of Marine Studies, and signed up to help UD scientists conduct the annual horseshoe crab survey.

From that point on, she says, she was hooked. She continued to assist with the horseshoe crab count, and as a high school sophomore, she conducted an investigation into the nesting sites of horseshoe crabs for a project that went on to win first place in the Sussex County, Del., Science Fair. She also won the President’s Environmental Youth Award and a DuPont Science Challenge Award for her research.

“Since I lived so close to the College of Marine Studies, I got in touch with the college to ask about a device that could measure the size of sand grains on the different horseshoe crab beaches,” Bradley says. “The college put me in touch with [then graduate student] Christine Muir, who showed me how to use the equipment. She was incredibly helpful and also met with me several times to go over my project, showed me how to use the University’s library system to do literature research and taught me some of the general marine ecology relevant to my project.”

When Bradley finished her project, she says, Muir spoke with Douglas Miller, associate professor and Muir’s adviser, who offered the high school student a full-time summer job in his lab. She started out by assisting graduate students, but as she learned more about the issues they were studying and the techniques being used, Miller encouraged her to become more independent. He also encouraged her to use the equipment for her own studies, which she did over the next two years of high school.

At the same time, Bradley says, her interest in and knowledge of horseshoe crabs grew. She learned that the crab has a compound in its blood that is used to test drugs for infectious bacteria and that research conducted on the crab’s eyes has resulted in much of what is known today about the function of human eyes. The horseshoe crab also is important to the ecology of Delaware Bay beaches, which host the largest spawning of horseshoe crabs in the world.

After graduating from high school, Bradley initiated the process to establish the horseshoe crab as Delaware’s official marine animal by sending an e-mail to Gov. Ruth Ann Minner. To her surprise, she says, she received an enthusiastic reply from the governor herself, suggesting that Bradley contact her local representative.

And, so, in July 2002, Bradley made history as she stood next to Minner as the bill was signed into law. To recognize Bradley’s role in this process, Minner and the Delaware Department of Natural Resources and Environmental Control presented her the Delaware Young Environmentalist of the Year Award.

Bradley, who enrolled at the University in August 2002, has been able to continue her involvement with the College of Marine Studies and to take advantage of UD’s opportunities for undergraduate research. In addition to working for Miller, she worked for Katharina Billups, assistant professor of oceanography, for several years and for Christopher Sommerfield, assistant professor of oceanography, for a summer. She says these opportunities gave her a richer experience and understanding of marine studies that she could apply to her own research. “Abigail is the most dedicated undergraduate I have ever come across,” Miller says. “She has a very realistic idea of what marine biology is and what is involved in conducting research.”

The summer after her sophomore year, Bradley was accepted into the College of Marine Studies’ annual summer intern program, largely sponsored by the National Science Foundation through its Research Experiences for Undergraduates (REU) program. The fellowship allows undergraduates to design and complete an original research project under the guidance of a faculty mentor.

Working with Miller, Bradley monitored the colonization of the Asian shore crab, Hemigrapsus sanguineus, in an area where riprap had recently been placed. The Asian shore crab is an invasive species in the Delaware Bay region and is typically found on rocky substrates such as riprap, groins, jetties, piers, mussel beds and oyster reefs in high-salinity coastal habitats.

Bradley’s research was designed to help scientists determine whether artificial hardening of the shoreline, a method used to combat beach erosion, may inadvertently facilitate the spread of invasive species. Her results also will be used in her senior honors thesis, which explores the marine ecology of rocky, intertidal habitats of the Delaware Bay.

“Even though my high school research focused on the horseshoe crab, I began to get interested in other areas of marine ecology, especially that of invasive species, while working in Dr. Miller’s lab,” Bradley says. “The construction of a new rock jetty at Roosevelt Inlet in the Delaware Bay in spring 2004 seemed like a great opportunity to study the colonization of different species to this new habitat.

“Only soft-bottom habitats, such as sand beach and marsh, occur naturally on the Mid-Atlantic coast. Therefore, when riprap is artificially emplaced, native species may not be as competitive as exotic ones that have already adapted to the rocky intertidal environment elsewhere.”

Last summer, Bradley completed another REU fellowship at the Bodega Marine Laboratory of the University of California at Davis, with a project focused on the effects of temperature on kelp forest ecology.

“I cannot imagine a more effective way of actualizing my awe of science and nature than the summer research fellowships I participated in in my sophomore and junior years of college,” Bradley says. “Even more rewarding is the sense of wonder that I experience when conducting my research.”

—Kari K. Gulbrandsen, EG ’91M