Methane production in contrasting wetland sites: Response to organic‐chemical components of peat and to sulfate reduction

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Abstract
We used methane‐production measurements of slurried peat to study controls of methane production in six contrasting Appalachian wetland sites. The sites differed widely in plant‐community composition and in rates of methane production, which varied from 3 μmol/L/day in slurried‐peat samples from a shrub‐dominated bog to 216 μmol/L/day in peat from a spruce‐forested wetland. Three controlling factors of methane production were examined: organic‐chemical components of the peat (e.g., hot‐water soluble, sulfuric acid soluble, sulfuric acid insoluble), concentrations of dissolved organic carbon, and rates of sulfate reduction. Peats from shrub‐dominated sites contained mostly acid‐insoluble organic matter, which was presumably recalcitrant to microbial decomposition. In contrast, peats from moss‐and sedge‐dominated sites contained mostly acid‐soluble organic matter, which was presumably labile. Differences of organic‐chemical components of the peat could explain about 50% of the variation in rates of methane production among samples from the sites. Rates of sulfate reduction in peat samples were relatively high (5–397 μmol/L/day), despite low in situ concentrations of dissolved sulfate (