The approach: I used a six-week research project as the context for teaching geomicrobiology subject material and the process of scientific inquiry. Specifically, my collaborating instructor and I asked students at each institution to design and conduct laboratory batch reactor experiments as a class, collect data, compile and interpret data, interpret results, present and defend design choices, and propose improvements, then make predictions for the experiment if it were to run for a longer period of time.
Early in the term, my class took a field trip to a petroleum-contaminated aquifer near Bemidji, MN. [click for field trip photos] This site has been studied extensively by the USGS and other scientists as an example of natural attenuation of hydrocarbons by in situ subsurface microorganisms, and it has produced new insight into our understanding of microbe-mineral-water interactions. The field trip allowed us to collect necessary materials such as sediment and groundwater that we later used in our experiments. Furthermore, the field experience helped students conceptually connect their experimental laboratory work to the field site. It also provided exposure to field sampling of sediment and groundwater and preservation techniques necessary for successful sampling of labile solutions and microorganisms. Due to lack of resources, the Allegheny students couldn’t attend; however, the Allegheny instructor attended and videotaped the field trip. To maintain consistency in experimental design between classes at each school, KU students constructed experimental samples in vessels for both institutions, then shipped them to Allegheny for analyses.
We also dedicated several class meetings to data discussions during which students in each class critically examined a particular dataset (i.e. one component of the system, such as pH, biomass, etc.). Different students were asked to prepare pertinent figures and tables for each data discussion. They were also encouraged to refer to course materials as a basis for interpreting data. Students needed to provide justifications for their interpretations and generate alternative hypotheses or null hypotheses. Although it felt forced at first, this interaction led students to make better interpretations as the semester went on. Students developed a critical eye for potential errors and became accustomed to trouble-shooting a technique to understand inherent discrepancies in data. These class meetings were essential for addressing some of the practicalities of scientific inquiry, such as imperfect data, and instrument and analyst error.
Assessment: To assess learning progress, we used three scaffolded assignments, a mid–term proposal, a group presentation, and a final report.
Assignments: To help familiarize students with the subject and develop a context for their research, I created short writing assignments to augment lectures. These assignments each had a similar format: several questions that increased in difficulty (within a single assignment) from basic definitions to conceptual synthesis, and ultimately asking students to design an experiment to address the topic.[click for writing assignment #1 and rubric here]
Mid-term proposal: In the third week of class Dr. O'Brien and I assigned the first major assignment to prepare students for the design and construction of the course experiment. After introducing the fundamentals of geomicrobiology and experimental design, we presented each class with a set research question: How do increases in silicate–bound Ni concentration impact microbially–mediated silicate weathering by a native microbial consortia?
Allegheny students were asked to consider aerobic consortia, while KU students considered anaerobic consortia. This division was based on the premise that each metabolic guild has different requirements for Ni, which, in turn, might impact weathering. We also gave the students some sense of our expected results. We then asked them to design an experiment to answer the posed question. For guidance, we gave them a defined number of issues that they had to address; we also built a grading rubric directly from these guidelines. [click for experimental design exercise]
Once the proposals were complete, we presented each class with a final experimental design and detailed instructions on how we would be constructing the experiment. We then had a discussion about the pros and cons of our decisions and alternate choices we might have made.
Group presentation: We assessed the ability of students to interpret and synthesize their data using group presentations. We based their grade on a rubric we distributed earlier in the semester. Students from the two schools interacted via digital slide presentations delivered during a teleconference session. Grading was based on presentation and interpretation of data, as well as questions posed and answered. [click for grading criteria for final project]
Final report: Originally Dr. O'Brien and I had envisioned a final report in which students came up with a completely new research question and design. However, because group proposals and presentations exposed some gaps in knowledge, we decided that students would benefit from continuing their evaluation of the course experiment. We therefore designed a final assignment based on the previous ones. It focused students' energy in a direction in which they had already invested and had confidence. We asked them to evaluate the original experimental design in light of the results collected and propose a new and improved design. We also asked them to predict the outcome of the current experiment were it to be continued. [click for writing assignment guidelines and grading criteria]| << Background | ^TOP^ | Student Performance >> |
