1. Decomposition and development:
A comparison of CO2 flux at Sourdough Trailhead
Cloe Dickson
Winter Ecology, Spring 2018
Department of Ecology and Evolutionary Biology
Mountain Research Station - University of Colorado Boulder
Cloe Dickson
2018
Decomposition and development
File type: pptx
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Keywords: decomposition, microbial respiration, CO2 flux, Sourdough Trailhead

2. What is decomposition?
The breakdown of organic matter into inorganic molecules
Performed by bacteria, fungi in the soil
Use respiration as an energy source for decomposition reaction (Boyd, 1995)
Can measure CO2 flux to find decomposition rate
Dependent on current conditions

3. How does decomposition work in the winter?
Temperature is key (a limiting factor)
“Insulating effect” of snowpack limits daily temperature fluctuations, creates conditions that are more conducive to decomposition process (Marchand, 2013)
Duration of snowpack cover also important for decomposition rate (Bowman, 2001)

4. What is the question?
Question: How does decomposition in Sourdough Trailhead parking lot compare to decomposition rates in areas where snowpack is not periodically removed? Do higher snowpack levels, such as snow banks pushed up by plowing, allow for decomposition at a higher rate than original snowpack?

5. Hypothesis As snow is removed (by plowing) …
Ground loses essential snowpack insulation
Temperature of ground decreases
Decomposition is inhibited by environmental conditions
As snow is pushed up into snow banks (by plowing) ...
Ground gains essential snowpack insulation
Temperature of ground increases
Decomposition occurs due to optimal environmental conditions

6. Methods
Necessary materials: shovel, CO2 analyzer, snow probe, temperature probe
Clear snow (when necessary) to expose soil for testing
Obtain temperature at surface using temperature probe
Place CO2 analyzer into soil and press ‘Y’
Repeat three times at each study site
Record information on data sheet (noting current environmental conditions such as snow depth, precipitation)

7. Methods Study site: Sourdough Trailhead parking lot, Nederland, CO
Four specific sites used: (1.) middle of parking lot, (2.) edge of parking lot, (3.) 5m and (4.) 15m from lot
Replicates and randomness (or lack thereof)
Three pseudoreplicates at each study site (12 total)
Plan versus reality

8. Results: single-variable ANOVA
ANOVA tests the difference between the means of independent groups
P-value is <0.001
Mean slope increases further from lot

9. Interpretation ANOVA test shows that data is statistically significant
P-value is <0.001 with level of significance (alpha) of 0.05
Can reject null hypothesis, or notion that there is no difference in the means of the CO2 flux slopes
Snow addition/removal changes environmental conditions (temperature)
Can support alternate hypothesis, or notion that at least one CO2 flux slope is different in the four sites

10. Future research
Important to know how ecosystem services are affected by humans
Decomposition rates are altered by manual snow removal (i.e. plowing) and respond to snow removal negatively
Can have larger implications on health of the surrounding ecosystem, natural resource management
Research in the future should use many (true) replicates
Study flawed by lack of randomness and lack of replication
Also need to isolate other confounding variables (trees)

11. Summary
Decomposition occurs in and around the Sourdough Trailhead parking lot
Dependent on environmental conditions (temperature, snowpack)
Trend of CO2 flux increases away from parking lot center
Many other factors that go into determining decomposition rate should be considered
Important in understanding human influence

12. Literature cited
Bowman, W. D. & Seastedt, T. R. (2001). Structure and Function of an Alpine Ecosystem: Niwot Ridge, Colorado. Oxford University Press: New York.
Boyd C.E. (1995) “Soil Organic Matter, Anaerobic Respiration, and Oxidation— Reduction.” Bottom Soils, Sediment, and Pond Aquaculture. Springer, Boston, MA
Marchand, P. J. (2013). “The Changing Snowpack.” Life in the Cold. University of New England Press: Hanover, New Hampshire.