The biogeochemistry of methane cycling in two Michigan peatlands

Temporal changes in methane emissions from two peatlands in Michigan were investigated over a two-year period. Seasonal changes in pools of porewater methane, sulfate, and acetate, a methanogenic substrate, were also measured. Mean daily fluxes of methane varied significantly from site to site, ranging from 0.6-11.6 mg CH;Porewater profiles of dissolved methane indicated as much as 75% of the net methane flux during the growing season was attributed to transport through plants. Low rates of methane consumption (-0.2 to -1.5 mg CH;The plant communities also appeared to alter methane flux from the peatland ecosystems by contributing labile substrates for methane production. During the late winter-early spring of both years, high concentrations of acetate (...