Greenhouse Gas Flux Response to Harvest of Typha x Glauca in a Great Lakes Coastal Wetland

Olivia Johnson, Olivia Johnson, Beth Lawrence
2016 DePaul Discoveries   unpublished
Research completed in Summer 2015 through microbial activity. Both CH4 and CO2 are radiatively active greenhouse gases (GHGs), and CH4 has a global warming potential 25 times higher than CO2 (Robertson, 1999 , Forster et al., 2007 . ABSTRACT Although harvesting invasive species can promote biodiversity during wetlands restoration, there is little known about this mechanical treatment's impacts on greenhouse gas flux, a significant biosphere-atmosphere interaction. We quantified greenhouse gas
more » ... ux response to experimental harvest of invasive hybrid cattail (Typha x glauca) at Cheboygan Marsh in Northeastern Michigan during the 2015 growing season. During each sampling campaign (July 15, July 31, August 12) we collected gas samples from static PVC chambers at 6 harvest and adjacent Typha control plots. Using gas chromatograph analysis, we found no significant difference in CH4 or CO2 flux between harvest and control plots on any date. Average CH4 flux rates for harvest and Typha control were 56.0 and 36.0 mg C m -2 h -1 respectively. Average CO2 flux rates for harvest and Typha control were 35.7 and 43.2 mg C m -2 h -1 respectively. From hourly I-Button temperature measurements, we found harvest plots had a higher average maximum daily temperature than Typha control plots. We found a positive linear relationship between reduction-oxidation potential and greenhouse gas flux on harvested plots. While our hypothesis of decreased greenhouse gas flux in harvest plots was not supported by our results, limitations in our experimental design indicate need for improved instrumentation and sampling procedure. Further, trends in temperature and redox data support need for more comprehensive inquiry into the interaction between temperature, harvest of Typha, and microbial production of greenhouse gases.
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