Teaching Environmental Geochemistry: An Authentic Inquiry Approach

ABSTRACT

A field-based environmental geochemistry course was developed at Western Michigan University for undergraduate geosciences and environmental studies students to (1) improve student understanding of complex environmental systems, specifically targeting lake systems; (2) facilitate student development of professional-level, field- and laboratory-based skills for lake water and sediment analysis; and (3) strengthen student teamwork and communication skills. In this course, students designed and completed a study of water quality in a local kettle lake. The instructor used short “question of the day” exercises, brief lectures, and in-class exercises to familiarize students with analytical and field techniques relevant to the posed problem. At the end of the semester, students presented their work in a public poster session and written report submitted to a local community association. The course was assessed using student work, a preinstruction experience survey, a postinstruction course evaluation, a pre- and postinstruction knowledge test, and a series of interviews with select students. Analysis of the full suite of assessment data suggests that students developed a significantly improved understanding of lake systems and the process of eutrophication and perceived that the course improved their analytical and interpersonal skills. However, lower-performing students (i.e., those with a lower grade point average) and students with weaker backgrounds in geochemistry tended to provide less sophisticated test responses and showed less ability to transfer knowledge gained in the course to other environmental systems. Overall, students reported a strong sense of satisfaction with the authentic inquiry and community-oriented nature of the course. Compared to students in the first year of the course, students in the second offering appeared to be somewhat less excited and engaged, which may reflect a perceived lack of novelty and new discovery about the field site and study question. Thus, to insure continued high levels of engagement of students in subsequent years, we recommend periodically shifting either the field site or the central research question addressed by the class.

Key words::

• eutrophication
• teaching biogeochemistry
• biogeochemical cycles
• limnology
• authentic inquiry

Acknowledgments

We thank the students in both course years who participated in this project, especially those who participated in the interviews, as well as the course teaching assistants, Angel Cuellar and Ryan Sibert. We also thank Julie Libarkin and Karen McNeal for helpful discussions and feedback regarding evaluation of student conceptions and the design of the knowledge test and other instruments. We appreciate the assistance of Yoko Furukawa, Christof Meile, and Kimberley Hunter in reviewing the pre- and postknowledge test. This work has been supported by the Geosciences Education Program of the National Science Foundation (GEO-0807578). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

FIGURE 1: Example of (A) an individual and (B) a group answer to a “question of the day (QOD).”

FIGURE 2: Selected results of student investigation of Woods Lake water chemistry. These data were collected November 21, 2009, and demonstrate that the lake remains unmixed and anoxic at depths below ∼9 m even in late fall. High levels of conductivity and chloride are likely the result of road-salt inputs.

FIGURE 3: Results of the pre- and postinstruction geochemistry knowledge test for (A) 2009 and (B) 2010. Open circles indicate interview subjects.

TABLE I: Alignment between general course goals, specific objectives within each of these goals that describe what students should know or be able to do by the end of the course, course activities designed to meet the goals and objectives, and methods for assessing whether goals and objectives have been met.

TABLE II: Self-reported demographic data from consenting students.

TABLE III: Weekly class activities, Question(s) of the Day, and homework assignments. In fall 2010 (second offering), students were also required to work a full day in the lab or the field on a Saturday or Sunday in weeks seven and ten.