Faculty Mentor(s)

Dr. Michael Philben, Geological & Environmental Sciences

Document Type


Event Date



Globally, peatlands store twice as much carbon as there is in the atmosphere as CO2. As average global temperatures continue to rise, the growth or decay of these carbon stores will play an important feedback for future climate change. This study examined the mechanisms behind the rate of decomposition in Sphagnum mosses, specifically the differences in cell wall chemistry between species. We hypothesized that mosses from different microtopographies will differ in rate of decomposition, as previous studies have shown that hummock mosses have higher concentrations of recalcitrant structural carbohydrates in their cell walls compared to hollow mosses. The Sphagnum moss was collected from the Miner Lake Bog in Allegan Township, Michigan. We sampled three sites for each species and a site for one terrestrial Polytrichum species for comparison of a non-Sphagnum moss. Moss was cleaned of all extra organic matter and separated into 15 replicate incubation bottles for each type of moss. The moss was adjusted to 70% of its water holding capacity and a native microbial inoculum was added. The incubation bottles were wrapped in foil to prevent further photosynthesis and stored to begin decomposition. The moss samples were analyzed by gas chromatography to measure the rate of CO2 production during decomposition. Our data shows the rate of decomposition of the Hollow moss was significantly higher than the hummock and the non Sphagnum moss. This is consistent with our hypothesis that structural carbohydrates in hummock mosses reduce their rate of decomposition. The control had no moss and was treated with inoculum but did not exhibit CO2 production, demonstrating that decomposition of organic matter in the inoculum did not affect the results. Our continuing work is using gas chromatography/mass spectrometry to determine the specific carbohydrates responsible for the observed differences in decomposition.


This work funded by Michigan Space Grant Consortium, NASA grant #NNX15AJ20H, Rex Johnson Geology Summer Research Fund and Smallegan Undergraduate Chemistry Research Fund.