Dr. Alyson Thibodeau, Earth Sciences

Mercury, Dragonflies, and Sustainability in Pine Grove Furnace State Park

The goal of my participation in the Valley and Ridge workshop was to better integrate sustainability and place-based education into ERSC 331: Geochemistry, an upper-level core  course in the Earth Sciences major. As a result of my participation in Valley and Ridge, I was able to learn about pedagogies for incorporating different aspects of sustainability into my course. This resulted in the development a semester-long, project-based, place-based, experiential learning experience for my students.

Over the course of the semester, students will investigate mercury pollution in Pine Grove Furnace State Park, an area that is about 15 miles south of Dickinson campus. Through this project, students will address a real-world problem: mercury contamination in aquatic ecosystems. Specifically, they will investigate mercury pollution within Laurel Lake, which is under an advisory due to elevated mercury levels present in the largemouth bass population (see Commonwealth of Pennsylvania Fish Consumption Advisories, 2018).

To investigate mercury pollution within the park, the students will collect and analyze both sediments and insects from Laurel Lake and the surrounding vicinity. In particular, students will focus on the collection and analysis of larval-stage dragonflies. Larval-stage or juvenile dragonflies may serve as indicators for mercury levels in aquatic ecosystems because they are (1) relatively long-lived and (2) predatory, feeding on other aquatic insects. Students will be able to compare the mercury content of the dragonfly nymphs to that of fish within Laurel Lake, and to the other dragonfly nymphs collected from around the United States. Fortunately, there are abundant mercury data available on dragonfly nymphs due to the “Dragonfly Mercury Project,” a citizen-science initiative in national parks across the United States to investigate mercury pollution at the continental-scale (see: https://www.nps.gov/articles/dragonfly-mercury-project.htm). Students will process, interpret, and write up their results as part of their coursework and will communicate their findings to managers at Pine Grove Furnace State Park in the form of a report or poster. It is anticipated that if the study is successful, it will be repeated every time the course is taught to establish a long-term record of mercury levels in the park.

Through this project, students will consider the biogeochemical cycling of mercury and the pathways for human exposure to methylmercury, which is a potent neurotoxin. Although this project heavily incorporates the environmental dimension of sustainability, the Valley and Ridge program made me aware of the importance of having students confront the social and economic dimensions of sustainability as well. Studying mercury pollution presents an excellent opportunity to discuss these dimensions because of the impact of mercury pollution on global fisheries and the food supply, especially in regions where people subsist on fish from contaminated waterways. Over the course the semester, students will read and discuss several articles that address these issues and demonstrate that they can articulate the broader social and economic impacts of mercury pollution around the world.