title: Using13C isotopes to explore denitrification-dependent anaerobic methane oxidation in a paddy-peatland.
abstract: Peatlands are organic-matter-rich but nitrogen-limited natural systems, the carbon/nitrogen (C/N) status of which are subject to increasing exposure from long-term nitrate (NO3-) fertilizer inputs and atmospheric nitrogen (N) deposits. To manage and protect these unique environments, an improved understanding of denitrification-dependent anaerobic oxidation of methane (DAMO) in peatlands is needed. In this study, we used stable isotope measurements and incubation with NO3-additions to facilitate an investigation and comparison of the potential DAMO rates in a paddy-peatland that has been influenced by N fertilizer over 40 years and an undisturbed peatland in northeast China. Monitoring of13CO2production confimed DAMO did occur in both the paddy-peatland and the undisturbed peatland, the rates of which increased with NO3-additions, but decreased logarithmically with time. When NO3-was added, there were no significant differences between the CH4oxidation in the paddy-peatland and peatland samples after 36 hours of incubation (97.08 vs. 143.69 nmol g-1dry peat) and the potential DAMO rate after incubation for 1 hour (92.53 vs. 69.99 nmol g-1h-1). These results indicate that the occurrence of DAMO in peatlands might be controlled by the amount of NO3-applied and the depth to which it penetrates into the anoxic layer.
authors.affiliation: State Environment Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun 130024, China.|School of Environment, Northeast Normal University, Changchun 130024, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Shi
authors.affiliation: State Environment Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun 130024, China.|School of Geographical Sciences, Northeast Normal University, Changchun 130024, China.
authors.forename: Zhongqiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Environment Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun 130024, China.|School of Environment, Northeast Normal University, Changchun 130024, China.
authors.forename: Chunguang
authors.initials: C
authors.lastname: He
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Environment Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun 130024, China.|School of Environment, Northeast Normal University, Changchun 130024, China.
authors.forename: Lianxi
authors.initials: L
authors.lastname: Sheng
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun 130023, PR China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Ren