About This Lesson
This activity examines how soil microbes, such as bacteria and fungi, are involved in carbon cycling. Students design experiments to explore the relationship between microbial respiration rates and soil variables such as temperature, habitat, soil type, and agricultural management choices. Four methods for measuring CO2 released from soil are provided, one in the field (CO2 probe), and three in the lab (CO2 probe, bromothymol blue (BTB) and acid-base titration).