Ecoenzymatic stoichiometry and microbial processing of organic matter in northern bogs and fens reveals a common P-limitation between peatland types

• Published in: Biogeochemistry 2014-08, Vol.120 (1-3), p.203-224
• Main Authors: Hill, Brian H, Elonen, Colleen M, Jicha, Terri M, Kolka, Randall K, Lehto, LaRae L. P, Sebestyen, Stephen D, Seifert-Monson, Lindsey R
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; atmospheric deposition; Biogeochemical cycles; Biogeochemistry; Biogeosciences; Biological and medical sciences; Bogs; carbon; Climate change; Decomposition; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Ecosystems; Environmental Chemistry; Enzymes; Exact sciences and technology; Fens; forests; Fundamental and applied biological sciences. Psychology; Global climate; Highlands; Life Sciences; Matter & antimatter; metabolism; nitrogen; Organic chemicals; Organic matter; Peat; Peatlands; phosphorus; Resource availability; Respiration; runoff; Soil chemistry; Soil horizons; Soils; Stoichiometry; Surficial geology; Synecology; Terrestrial ecosystems; Watersheds
• ISSN: 0168-2563; 1573-515X
• DOI: 10.1007/s10533-014-9991-0

We compared carbon (C), nitrogen (N), and phosphorus (P) concentrations in atmospheric deposition, runoff, and soils with microbial respiration [dehydrogenase (DHA)] and ecoenzyme activity (EEA) in an ombrotrophic bog and a minerotrophic fen to investigate the environmental drivers of biogeochemical cycling in peatlands at the Marcell Experimental Forest in northern Minnesota, USA. Ecoenzymatic stoichiometry was used to construct models for C use efficiency (CUE) and decomposition (M), and these were used to model respiration (Rₘ). Our goals were to determine the relative C, N, and P limitations on microbial processes and organic matter decomposition, and to identify environmental constraints on ecoenzymatic processes. Mean annual water, C, and P yields were greater in the fen, while N yields were similar in both the bog and fen. Soil chemistry differed between the bog and fen, and both watersheds exhibited significant differences among soil horizons. DHA and EEA differed by watersheds and soil horizons, CUE, M, and Rₘ differed only by soil horizons. C, N, or P limitations indicated by EEA stoichiometry were confirmed with orthogonal regressions of ecoenzyme pairs and enzyme vector analyses, and indicated greater N and P limitation in the bog than in the fen, with an overall tendency toward P-limitation in both the bog and fen. Ecoenzymatic stoichiometry, microbial respiration, and organic matter decomposition were responsive to resource availability and the environmental drivers of microbial metabolism, including those related to global climate changes.