Benjamin Pyenson '09 (left) at the Plum Island estuary with
fellow research assistant Aaron Strong (Swarthmore '06).
Haverford Junior Spends a Semester as "The Pyrite Guy"
During the fall of 2007, Pyenson slept, ate and breathed pyrite while taking part in the Semester in Environmental Science (SES) program at the Marine Biological Laboratory (MBL) in Woods Hole, Mass. Sponsored by MBL’s Ecosystems Center, the program gives serious science students the chance to conduct independent, intensive hands-on ecological research in the forests, ponds and estuaries of the Cape Cod area.
“People in the program called me ‘the pyrite guy,’” laughs Pyenson. “I just thought it was a really interesting mineral, and a valuable way to study how sulfur is stored in sediment.”
Pyenson, a geology major at Bryn Mawr (and probable double major in biology), first became interested in SES when program director Ken Foreman visited campus last spring for an information session. He also spoke with Ford alumni and former SES participants Will Longo ’07 and Rowan Spivey ’07, both of whom encouraged him to pursue the program; in fact, Longo was one of his TAs during the semester. (Other former Haverford students who spent a semester at Woods Hole include Michael Fichman ’05, Josh Havassy ’04, and John McKay ’99.) Pyenson says he was impressed by the “amazing amount of resources MBL offers in the Woods Hole community—you’re close to a ton of different ecosystems.”
His research project focused on the effects of nitrate fertilization on pyrite oxidation. “Nitrate fertilization is common in estuaries and salt marshes,” he explains. “In the Woods Hole area, there’s lots of sewage, increased development and fertilizers from lawns—most of the nitrate seeps into groundwater and ends up in an estuary where water meets land.” The oxidation of pyrite, a mineral often found in sediments and coal mines, is also a problem in salt marshes. Pyenson wanted to determine what, if any, influence nitrate fertilization has on pyrite oxidation.
To conduct his research, he went to the Plum Island estuary and, with the help of two MBL research assistants, extracted eight salt marsh sediment cores, four from a fertilized plot, four from a non-fertilized control plot. He also took cores from nearby Great Sippewissett Marsh and incubated them over the course of 15 days with varying amounts of sulfate and nitrate concentrations. Afterwards, he measured them to see whether there was a loss of pyrite, or if pyrite was being stored in cores.
In the end, Pyenson and his team did not find a correlation between pyrite oxidation and nitrate fertilization from either the long-term (Plum Island) or the short-term (Great Sippewissett Marsh) data. “Our data suggests that pyrite may actually be stored over the long-term due to nitrate, but we can’t be sure enough to conclude it,” he says. “Science is about experiments, so you can’t always expect to receive the results you want to see, and you have to be prepared to make a lot of mistakes.”
However, the group did find results that shed light on salt marshes’ use of nitrate. “We found nitrification, the process of nitrate formation, occurring in non-fertilized salt marshes over time,” says Pyenson. “Our results from the fertilized cores also show that salt marshes are good at consuming nitrate, where it is probably being used for growth and/or converted to other nitrogen compounds.” He was surprised to find that many scientists at the MBL were interested in nitrate’s effect on other aspects of salt marsh ecosystems, and were excited by results he had not considered relevant to his study.
“I guess it goes to show the cooperative and unpredictable nature of environmental science,” he says.
“[Pyenson] was a pleasure to work with,” says Anne Giblin, Pyenson’s project adviser and a Senior Scientist at the MBL. “He is one of the hardest working students I’ve ever advised. He picked a project he was really interested in even though it required a great deal of work, never lost his enthusiasm for the topic and was always cheerful even when working long hours.” Even when his data was hard to interpret, says Giblin, “he took it as a challenge to be excited about and worked through the problems.”
Pyenson wrote up his results in an end-of-semester paper and presented his findings at a public symposium. It was hardly the first presentation he’d had to give during the semester; they had become a weekly requirement. “You go out in the field at the beginning of the week and study a focused topic, get results, go into the lab and analyze them, work them up on computers, and then on Friday present the results in front of the faculty,” he says. “You get to see how science is made from start to finish.” MBL professors offered feedback and advice to strengthen the students’ presentation skills.
“I thought my final presentation was really improved from what I’d done in my previous classes at Haverford and Bryn Mawr,” he adds. “It was a night and day difference in terms of what I know now.”
In addition to the science courses and labs, students in the SES also take a science writing seminar, which teaches them not how to write scientific papers, but how to write their results in such a way that the general public—especially those not inclined to science—can grasp their meaning. “It’s a useful skill to learn how not to talk in science jargon,” says Pyenson. “If you ever want to do anything with policy, for instance, you have to be able to communicate what you’re saying in a clear, concise way.”
Pyenson feels his participation in SES will be beneficial not only to his academic future (“I’ve gotten a better sense of what I want to study”), but also to his current work with Haverford’s Committee for Environmental Responsibility (CER), of which he is a member. “My time at the MBL will help me understand the issues the committee deals with, and what changes we should make to the campus environmental policy,” he says. “A semester studying environmental science gives me a better background to read the volatility of issues, and decide how to proceed with them.”
Pyenson hopes that students who may be dissuaded from pursuing a domestic study-away semester because it isn’t considered as fun or interesting as an international one will give a closer look to the Semester in Environmental Science at the Marine Biology Laboratory in Woods Hole. “It’s the top place to go if you’re interested in ecology or environmental science,” he says.