ePrints

Evaluating the Classical Versus an Emerging Conceptual Model of Peatland Methane Dynamics

Lookup NU author(s): Professor Yit Arn TehORCiD

Downloads

• Published version [.pdf]

Licence

This is the final published version of an article that has been published in its final definitive form by Wiley-Blackwell, 2017.

For re-use rights please refer to the publisher's terms and conditions.

Abstract

Methane (CH₄) is a potent greenhouse gas that is both produced and consumed in soils by microbially mediated processes sensitive to soil redox. We evaluated the classical conceptual model of peatland CH₄ dynamics - in which the water table position determines the vertical distribution of methanogenesis and methanotrophy - versus an emerging model in which methanogenesis and methanotrophy can both occur throughout the soil profile due to spatially heterogeneous redox and anaerobic CH₄oxidation. We simultaneously measured gross CH₄ production and oxidation in situ across a microtopographical gradient in a drained temperate peatland and ex situ along the soil profile, giving us novel insight into the component fluxes of landscape‐level net CH₄ fluxes. Net CH₄ fluxes varied among landforms (p < 0.001), ranging from 180.3 ± 81.2 mg C m⁻² d⁻¹ in drainage ditches to −0.7 ± 1.2 mg C m⁻² d⁻¹ in the highest landform. Contrary to prediction by the classical conceptual model, variability in methanogenesis alone drove the landscape‐level net CH₄ flux patterns. Consistent with the emerging model, freshly collected soils from above the water table produced CH₄within anaerobic microsites. Even in soil from beneath the water table, gross CH₄production was best predicted by the methanogenic fraction of carbon mineralization, an index of highly reducing microsites. We measured low rates of anaerobic CH₄ oxidation, which may have been limited by relatively low in situ CH₄ concentrations in the hummock/hollow soil profile. Our study revealed complex CH₄ dynamics better represented by the emerging heterogeneous conceptual model than the classical model based on redox strata.

Publication metadata

Author(s): Yang WH, McNicol G, Teh YA, Estera-Molina K, Wood TE, Silver WL

Publication type: Article

Publication status: Published

Journal: Global Biogeochemical Cycles

Year: 2017

Volume: 31

Issue: 9

Pages: 1435-1453

Online publication date: 30/08/2017

Acceptance date: 26/08/2017

Date deposited: 13/06/2019

ISSN (print): 0886-6236

ISSN (electronic): 1944-9224

Publisher: Wiley-Blackwell

URL: https://doi.org/10.1002/2017GB005622

DOI: 10.1002/2017GB005622

Altmetrics

Share