Measuring Soil Microbial Activity

In this activity, students examine the relationship between soil microbes and carbon cycling through self-designed experiments exploring “microbial respiration rates and soil variables such as temperature, habitat, soil type, and agricultural management choices.” Three different techniques for measuring released carbon dioxide from the soil are provided; two for in-lab use and one for field research. Targeted at middle school through undergraduate students (grades 6 through 16), the activity requires a familiarity with the components of experimental design, data collection, and data analysis as well as a basic understanding of cellular respiration, carbon cycle, the role of soil microbes in ecosystems, and the role of carbon dioxide as a greenhouse gas. The time needed for this activity varies by technique and experimental design, and may range from three to seven 50-minute class periods spread out over a one to two week period. The required supplies depend on the activity and detailed instructions can be found in the activity description. The downloadable package, "Measuring Soil Microbial Activity," is a .zip file (19.1 MB) and includes: teacher instructions and answer key, student pages, carbon sequestration in soils, soil microbes presentation, types of soil microbes and their functions in ecosystems, and sample data.