Production of methane and ethylene in organic horizons of spruce forest soils

Abstract

Concomitant production of CH₄ and C₂H₄ was measured during anaerobic laboratory incubations of organic soils collected from Appalachian red spruce forests. Ethylene production generally exceeded methanogenesis, with greater production occurring in L and F compared with H and Al soil horizons. Slerilants significantly reduced production of both gases in all soils. However, treatment with 2-bromo ethane sulfonic acid (BES) or chloramphenicol decreased C₂H₄ but not CH₄ production. Methane production was not further stimulated by the addition of non-limiting concentrations of H₂. Arrhenius slopes for CH₄ compared with C₂H₄ production at temperatures from 5 to 45 C were not significantly different among any of the soils tested. Anaerobiosis due to water saturation may produce sufficient C₂H₄ to adversely affect plant root growth, however, coniferous forest soils appear to be minor potential sources of atmospheric methane. The methane produced in these soils could have resulted from microorganisms other than methanogenic archaebacteria.