Anaerobic Oxidation of Methane in Terrestrial Ecosystems (AOMTE): mechanisms and ecological relevance
Final Report Abstract
Understanding key mechanisms of the anaerobic oxidation of methane (AOM) in terrestrial ecosystems with intensive CH4 turnover (peatlands and rice paddies) which control CH4 emissions globally, is one of the critical tasks for broad scientific community. Mechanistically, AOM is the process which can be positively considered in the context of the climate change. The current project filled apparent knowledge gaps and assessed the potential of studied ecosystems for AOM not only under the controlled conditions but – for the first time – directly in the field. Novel application of widely used method of passive diffusion chambers (PDCs) made it possible to estimate in situ potential of CH4 oxidation based on 13C-isotope labeling approach. It is important to note, that both types of CH4 oxidation – aerobic and anaerobic – could be targeted by this method. Although, focusing on AOM apparently requires strict caution for the O2 contamination via not tight connections or inaccurate manipulations. As a separate “know-how”, the insertion of PDCs into deep peat by means of reverse usage of peat augers is very valuable approach which can be acknowledged in various research activities in peatlands or other ecosystems with soft substrates (sediments). One of the big advantages of this approach is the cause of minimal disturbance of the substrate during PDC installation. We also confirmed the suitability of PDC method for laboratory incubation studies, which can substitute the commonly used shaking and minimizing microcosm disturbance. This appeared to be especially critical for the determination of AOM potential, since rates with shaking were 1.2-3.0 times lower than under static conditions. Importantly, results of the project discovered that AOM in northern peatlands and Chinese rice paddies can be responsible for consumption up to ~6 Tg of C-CH4 annually, hereby confirming these ecosystems as valuable players in offsetting global net CH4 emissions (by 10-20%). Finally, the outcomes of the current project are planned to be used in preparation of the next research proposal on discovering of mechanisms and overall potential of CH4 turnover in thermokarst lakes of permafrost regions.
Publications
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First-time in situ Belowground Labeling for CH4-turnover Studies: a Case Experiment at a Swedish Boreal Peatland. American Geophysical Union, Fall Meeting 2018, abstract id. B43F-07
Dorodnikov M., Knorr K.-H., Nilsson M.B.
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Shaking of microcosms underestimates anaerobic methane oxidation in paddy soil: evidence from headspace- and belowground 13C isotope labeling. American Geophysical Union, Fall Meeting 2018, abstract id. B41H-2823
Fan L., Shahbaz M., Ge T., Wu J., Dippold M. A., Thiel V., Kuzyakov Y., Dorodnikov M.
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2019. To shake or not to shake: 13C-based evidence on anaerobic methane oxidation in paddy soil. Soil Biology and Biochemistry, 133, 146-154
Fan L., Shahbaz M., Ge T., Wu J., Dippold M., Thiel V., Kuzyakov Y., Dorodnikov M.
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2019. To shake or not to shake: silicone tube approach for incubation studies on CH4 oxidation in submerged soils. Science of the Total Environment, 657, 893-901
Fan L., Shahbaz M., Ge T., Wu J., Kuzyakov Y., Dorodnikov M.
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Anaerobic oxidation of methane (AOM) in paddy soil: the alternative electron acceptors. Geophysical Research Abstracts, 21, EGU2019-1421-2, 2019
Fan L., Ge T., Wu J., Dippold M., Thiel V., Kuzyakov Y., Dorodnikov M.
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2020. Anaerobic oxidation of methane in paddy soil: Role of electron acceptors and fertilization in mitigating CH4 fluxes. Soil Biology and Biochemistry, 141, 107685
Fan L., Dippold M., Ge T., Wu J., Thiel V., Kuzyakov Y., Dorodnikov M.
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2021. Active metabolic pathways of anaerobic methane oxidation in paddy soils. Soil Biology and Biochemistry, 156, 108215
Fan L., Schneider D., Dippold M., Wu W., Gui H., Ge T., Wu J., Thiel V., Kuzyakov Y., Dorodnikov M.
