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.