A TEAM-BASED APPROACH TO TEACHING ENVIRONMENTAL HISTORY USING LAKE SEDIMENTS

The interdisciplinary nature of lake sediment research makes it accessible and engaging for undergraduate students from a wide range of disciplinary backgrounds. During a 3.5-week intensive “January-term” course, 11 students from Gustavus Adolphus College (Gustavus) collected sediment cores from a human-made lake and chose teams in which they would analyze one category of contaminant or a proxy of environmental quality. The course was taught at an introductory level with no prerequisites and it attracted biology, chemistry, environmental studies and non-science majors. After one week of introductory lectures and activities, the class collected sediment cores from Lake Hallett, a gravel pit in St. Peter, MN that filled with groundwater after being abandoned in 1937. The lake is now a city park and is a source of controversy – and is thus interesting to students – because from 1968-2001 the city’s storm sewers discharged into the lake. Citizens still question whether there was lasting environmental damage to the lake from that time period.

Students organized into four teams and worked largely independently in the second and third weeks of the term. The short term’s flexible schedule allowed the instructor to meet individually with each team for 1-2 hours per day to teach lab techniques and assist with instrumentation and data analysis. One group characterized sediments using magnetic susceptibility, high-resolution imagery and loss-on-ignition. A second group qualitatively characterized diatom assemblages, using handbooks and manuals. A third group measured biogenic silica, and was trained to use an inductively coupled plasma mass spectrometer (ICP-MS) to do so. The fourth group also learned to operate the ICP-MS to measure trace metal and Pb-isotope concentrations. All analytical work was done at Gustavus except imaging and magnetic susceptibility, which were performed at LacCore, University of Minnesota. The course culminated with all teams contributing to an oral presentation to students, faculty and members of the public, and to a poster presented at a campus symposium. The variety of proxies and research topics chosen by the teams reflected the diverse interests of the students, promoted a holistic understanding of the lake’s history, and contributed to a lively classroom environment.