Faculty Research

Daniel Thornhill 2009

A conversation with Emily Guerin '09

All semester I had been meaning to go to the Coastal Studies Center (CSC) to look at Dan Thornhill’s coral experiments, but fortunately the visit was delayed until a warm, clear Friday in early April—a perfect time to head out to the site. I picked Dan up behind Druckenmiller Hall and we drove out to Harpswell. He didn’t have a car on campus because he tries to walk from his house every day, a half-hour commute. As we drove out Harpswell Road, we discussed biking out to the Center and Thornhill advised me to watch out for cyclists on the windy, narrow roads—a caution born from being married to the head of the Bicycle Coalition of Maine.

dan thornhill feeding coralsAs the Doherty Marine Biology Post-Doctoral Scholar, Thornhill spends a lot of time at the CSC. He studies marine invertebrates, especially corals and the unicellular algae that live inside the coral’s tissues. He is interested in the symbiotic relationship between the two, and how that relationship is affected by changing environmental conditions. According to Thornhill, the corals get energy from the algae, or symbionts. In exchange, the coral provides a safe home for the algae. Currently he is studying the symbionts in a coral that lives in  the Gulf of Maine, one of the few found this far north. He is attempting to determine the costs and benefits of the coral-algae symbiotic relationship through controlling water temperature and light in the CSC’s marine lab.

After arriving at the CSC, we walked down the dirt road to the marine lab. Tree swallows flew low over the fields surrounding the farmhouse, and we heard other birds off in the forest. It was cooler and windier out here than on campus, and I imagined that on hot summer days it must be an ideal place to work. Thornhill opened the lab and motioned me over to one of the many seawater tanks. This one contained his corals, greenish-white structures that I had seen before washed up on beaches in Florida. He mixed food for them with water in a small jar, and used a pipette to propel the food towards them. Excitedly, he pointed out how the corals capture the tiny food particles and push them towards their mouths.

The many tanks around us contained specimens for marine biology classes, and as Thornhill pointed out various sea anemones and crustaceans the noise of seawater being pumped in and out of the tanks was a low drone in the background. He showed me a pink, fleshy anemone with stubby tentacles that waved slowly in the circulating water. In another tank dozens of starfish were piled on top of each other. In a third, creatures that looked like translucent lipstick tubes grww out of the grey sediment on the bottom. As I peered into the tanks, I felt like Thornhill was granting me membership to the small club of people that has ever seen animals like these before. I asked him if part of the reason he was interested in marine biology was the thrill of knowing that few people except scientists see these creatures.

But Thornhill became attracted to the subject in a roundabout way. While studying zoology at Michigan State University he worked as a field researcher in the deserts of New Mexico, an experience he described as “a summer of desert solitude.” Eager to explore other areas of biology, he  took a fellowship at the Woods Hole Oceanographic Institution in Woods Hole, MA the following summer. There he studied “really bizarre worms” that have no mouth or digestive system but are full of symbiotic bacteria. This work on marine symbiosis introduced him to corals, which would eventually captivate him and lead him to the reefs of Australia, Belize and the Bahamas to study.

Thornhill received his Ph.D. from the University of Georgia and worked as a post-doc at Auburn University afterwards. Although he described himself as “a product of large public institutions,” since coming to Bowdoin last August he realized that he is more interested in working at a small liberal arts school, mostly because of the emphasis on teaching. But Thornhill also appreciates the marine lab and research opportunities, which he believes are “pretty unusual” for a school of this size.

This year Thornhill has taught Coral Reef Biology and supervised an honors project. This summer, he will continue doing marine research in collaboration with three Bowdoin students in the marine lab. His students will study corals, but also a whalebone-eating worm. He plans to sink whalebones throughout Casco Bay and see if the worms will take the bait.

After a thorough peek into every tank, we walked down to the dock, which jutted out from the striated rocks along the shore and into the deep water. Last May, Bowdoin trustees boarded a schooner and sailed to Cook’s Lobster House from the CSC. But today the dock was empty; other than the wind and quiet waves the only noise was the churning seawater intake pump that sent the water to the marine lab on shore.