GREEN, STINKY, AND SICK: UNDERGRADUATES' CONCEPTIONS OF EUTROPHICATION
Data collected during the first two offerings of the course (Fall 2009 and Fall 2010) included experience, attitude, and content knowledge instruments; students’ individual and group work; and a series of semi-structured interviews with ~ 25% of the students in the course. Here we focus on our analysis of these interviews, which were primarily used to follow up with students about their responses to in-class writing assignments and probe students’ understandings of biogeochemical cycling, lake systems, and the eutrophication process (as well as its causes and consequences). We used qualitative coding methods to delineate conceptions our interview subjects held before, during, and after completing the course.
Areas in which students made the largest content knowledge gains (as indicated by pre-/post-testing and interview data) were: (1) Phosphorous binding to and release from lake sediments. (2) Lake quality assessment techniques and tools. (3) Nitrogen speciation and conversion processes. (4) Factors regulating dissolved oxygen levels in the water column. Analysis of the 2009 and 2010 interviews indicate that interview subjects’ pre-course conceptions of eutrophication vary dramatically in correctness, completeness, and connectedness. Some interviewees had almost no familiarity with or understanding of eutrophication. Many interviewees initially appeared to understand the process of eutrophication but had difficulty clarifying and applying terminology and struggled to explain causal mechanisms. Post-course, interview subjects demonstrated a more accurate and cohesive understanding of eutrophication and related processes.