FIELD INVESTIGATIONS OF A CAMPUS POND FOSTER INTERDISCIPLINARY APPROACHES ACROSS THE SCIENCES

Bryn Mawr College, in collaboration with local authorities, built a storm water retention pond in 2001. Since its construction, the authors have devised and carried out student field exercises as lab projects in introductory, intermediate and advanced courses in the departments of geology and chemistry. These courses include How the Earth Works, Earth Systems and the Environment, General Chemistry, Sedimentology, and Low-temperature Geochemistry. Exercises in these courses address common themes including basic field mapping, sampling/data analysis, runoff/stream flow, biodiversity and water quality issues. The incorporation of field exercises focused on the pond has reinforced the interdisciplinary nature of our multi-department environmental studies program, and has catalyzed conversations concerning course content and learning goals.

To varying degrees, students develop an understanding of the pond as a small-scale analogue of a hydrologic and sedimentary basin, as well as of a biogeochemical system involving primary productivity and nutrient cycling. In introductory courses students make and compare topographic maps with their observations of the pond basin. Introductory students also measure dissolved oxygen and temperature to calculate whether the pond is over- or undersaturated with oxygen. General chemistry students have measured the concentration of chemical constituents to evaluate whether the pond meets drinking water standards for those constituents. For some chemistry majors these exercises are their only experience with outdoor fieldwork and sampling. Students in Sedimentology use a small boat to measure vertical profiles to evaluate the pond as small-scale basin wherein organic carbon-rich sediments are deposited. Students have observed elevated algal growth (and oxygen supersaturation) near the surface, whereas the sinking of excess organic matter into the poorly ventilated, deepest part of the pond produces suboxic-to-anoxic conditions. In Low-temperature Geochemistry, students collect and analyze the nutrient (e.g., nitrate) content of water in various parts of the pond system and have documented reduction of nutrient concentrations, presumably by primary productivity uptake, as water passes through the system.