By Julia Robins, Virginia Sea Grant Student Correspondent
When Annie Murphy came to Virginia to study nutrients in Chesapeake Bay, she didn’t expect her studies would lead her to Italy.
Murphy, a Ph.D. student at Virginia Institute of Marine Science and Virginia Sea Grant Fellow, studies how clams affect nitrogen in the Bay. Recalling three years ago when she started her work, she says there were very few published studies about clams and nitrogen.
“[M]ost people are looking at oysters and the effects of oysters on nitrogen cycling,” she says.
Most of what she found was written by Daniele Nizzoli, a research scientist at University of Parma, Italy. Murphy jokes, “He was kind of like a movie star in my eyes.”
Although there was less research on clams compared to oysters, clams are as important to Virginia. The state leads the nation in clam farming. Millions of dollars worth of clams are produced annually in hundreds of acres of coastal waters. What’s more, understanding how these clams and clam farms affect nutrients could affect the industry’s long-term health and growth.
Clams both remove and recycle nutrients to the water. By filtering water to get their food, they take some nutrients out, but when they excrete waste, they add some back. If clam densities are high, nutrients could accumulate in a small area and cause blooms of algae that reduce oxygen in the water column when they die and decompose, a symptom of eutrophication.
To learn more about how clams affect the water over the long-term, Murphy’s advisor Iris Anderson, VIMS, sent Murphy to the University of Parma in Italy for three weeks in June 2013. There she met Professor Pierluigi Viaroli and his research team, including Nizzoli whose name Murphy found in all of those research papers. The team discussed their findings at a research site called the Sacca Di Goro, a lagoon located on the Northern Adriatic coast just south of Venice.
“They’ve been working in that system for over 20 years now, and they have a pretty good grasp on what’s happening with their clams and their lagoon, while we’re kind of just starting up. So they’re a great resource to have,” says Murphy.
While helping sample and learn about the Sacca Di Goro, Murphy learned that the lagoon system was very different from Chesapeake Bay. First off, the lagoon gets a large influx of nitrogen from nearby agricultural land. Because the lagoon waters flush slowly due to the physical shape of the system, the clam beds are especially at risk of eutrophication as nitrogen concentrates in the system, a problem that clam farmers and researchers are still trying to address. For the Chesapeake, the eutrophication risk hasn’t been as pronounced as the daily tides help flush the creeks of excess nutrients.
For Murphy, learning from these experienced scientists was a great opportunity. She learned specifics about research methods and how other bodies of water compare to ones at home.
“It was a fantastic opportunity to discuss my research with PIs that have a wealth of experience in our field,” says Murphy. “Our discussions have continued… I’m excited to continue collaborating with them in the future.”
Murphy plans to devote a chapter of her dissertation on her work in Italy.
