HR: 14:00h
AN: NB33U-03 INVITED     [Abstracts]
TI: How Ecosystems Breathe: Measuring Respiration of Soil
AU: * McTammany, M E
EM: mmctamma@bucknell.edu
AF: Bucknell University, Biology Department, Lewisburg, PA 17837 United States
AB: Curriculum for general ecology labs often uses in-lab exercises and computer simulations to demonstrate ecological principles rather than experimental field projects. In addition, ecosystem processes can be difficult to incorporate into general ecology labs because the techniques require sophisticated equipment or complex field designs. As an alternative to in-lab projects, I have integrated field measurement of soil respiration into my general ecology lab to teach students aspects of experimental design (sampling, replication, error, etc.) and to demonstrate how organism-level processes operate beyond single organisms in nature and are influenced by environmental conditions. In a program laden with biomedical interests, analogies between organisms and ecosystems are quite appealing to students. Students in my general ecology course complete a 2-week field project in which they measure soil respiration inside a dark microcosm chamber. We use 10% KOH to trap evolved CO₂ and titrate unreacted KOH in lab using 1N HCl. The protocol is simple, only requires some chemicals, and can be used in many different habitats (including flower beds on campus) quite easily. Potential experiments could involve varying environmental conditions, such as soil moisture, nutrient availability, gaseous environment, carbon supply, or temperature, to affect soil respiration rate.
DE: 0800 EDUCATION
DE: 0820 Curriculum and laboratory design
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly