Soil Respiration Module
- By analyzing a prepared soil respiration dataset from a long term C cycle research site:
- Recognize that soil respiration rates at a location vary across time scales, e.g., from days to seasons
- Analyze relationships between soil respiration rates and its potential drivers
- Make predictions for how changes in drivers will affect soil respiration rates
- Download and interpret global soil respiration data products from an online archive
- Recognize and describe ways in which soil CO2 emissions vary across space, e.g., different ecosystems or biomes; develop explanations for these differences
- Recognize that interannual variation in soil CO2 emissions also varies across space and explain what may drive this variation
- Appreciate how large-scale spatial data products are made, and how the methods of their creation affect the inferences that can be drawn from them
Context for Use
This entire module can be completed in one 2-3-hour lab period or two 50-minute lecture periods for introductory or intermediate level students. If the activity was introduced ahead of time and students have used Excel before, Activity A could be completed in a single 50-60-minute lecture period, but you may then want to budget additional time following class for students to complete Activity B.
This module is recommended for introductory or intermediate Geology and Environmental Science courses. We anticipate the module could be used in a variety of courses. Module materials can be tailored to increase or decrease the background information depending on students' quantitative skills.
Description and Teaching Materials
- Activity A: Students make one-year time-course graphs of climate variables and high-resolution [short-term] time course graphs of soil respiration and climate variables, and calculate total efflux.
- Activity B: Visually inspect the patterns of global spatial variation of carbon emissions and soil respiration, and complete readings.
- Assign pre-class readings.
- Disperse student handouts in class: Student Handout (Microsoft Word 2007 (.docx) 106kB Feb5 20), Student Dataset (Excel 2007 (.xlsx) 131kB Dec27 16).
- Discussion of pre-class readings.
- Instructor gives brief PowerPoint presentation on soil respiration and the C cycle, and environmental implications.
- At the end of the presentation, the instructor demonstrates how to plot a one-year time course graph of soil respiration rates. Also, discuss interpretation of variability and demonstrate the use of regression to attempt to explain variability.
- Students complete Activity A.
- Depending on time and comfort with the subject matter, the students then complete Activity B of the module by acquiring global soil respiration data products.
a. Global Patterns of Carbon Dioxide Emissions from Soils on a 0.5 Degree Grid Cell Basis; http://cdiac.ornl.gov/epubs/db/db1015/db1015.html
b. Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis; http://cdiac.ornl.gov/epubs/ndp/ndp081/ndp081.html
- Students interpret the patterns in the two data products in light of the analyses they have done.
- Soil Respiration Module - Instructor's Manual (Microsoft Word 2007 (.docx) 771kB Feb5 20)
- Soil Respiration Module - Instructor's PPT (PowerPoint 2007 (.pptx) 8MB Sep3 19)
- Soil Respiration Module - Student Handout (Microsoft Word 2007 (.docx) 106kB Feb5 20)
- Soil Respiration Module - Data (Excel 2007 (.xlsx) 131kB Dec27 16)
Teaching Notes and Tips
In Activity A, students make one-year time-course graphs of climate variables and high-resolution [short-term] time course graphs of soil respiration and climate variables, and calculate total efflux.
In Activity B, students inspect the patterns of global spatial variation of carbon emissions and soil respiration, and complete readings.
Notes, tips, and answers are provided in the following files:
References and Resources
Suggested pre-class readings:
- Carbon cycle overview: http://earthobservatory.nasa.gov/Features/CarbonCycle/
- University of Michigan Biological Station carbon (C) cycle research site: http://flux.org.ohio-state.edu/site-description-umbs/
- Kirschbaum (1995) Soil respiration paper: http://www.sciencedirect.com/science/article/pii/003807179400242S
- Kirschbaum, M. F. (2013). Seasonal variations in the availability of labile substrate confound the temperature dependence of organic matter decomposition. Soil Biology & Biochemistry, 57568-576.