Control of organic carbon mineralization by alternative electron acceptors in four peatlands, Central New York State, USA

Abstract

ABSTRACT Terminal mineralization of organic carbon (C) in northern peat soils usually produces more carbon dioxide (CO2) than methane (CH4), but the maintenance of microbial CO2 production is unclear. Carbon dioxide production relies on oxygen (O2) or alternative (to O2) electron acceptors (NO3−, Fe(III), SO42−). We examined rates of CO2 production and CH4 production in peat soils from two ombrotrophic bogs and two minerotrophic fens incubated in vitro with and without added glucose (an electron donor) and added electron acceptors. Soil interstitial water had dissolved NO3− (2–17 µmol L−1) in three sites, and SO42− (2–20 µmol L−1) and Fe(III) (0.02–0.8 µmol L−1) in all four sites. Peat soils incubated in vitro without added glucose or electron acceptors had rates of CH4 production between 0.2 and 1.5 µmol g−1 day−1 and rates of CO2 production between 8 and 17 µmol g−1 day−1. Added glucose increased CO2 production in all of the peat soils, although adding an electron acceptor with glucose had no additional...