Methane Oxidation in the Rhizosphere of Wetland Plants. Final Report
The main objective of the project was to improve predictions of future CH 4 emissions from natural wetlands. This objective was motivated by the fact that methane (CH 4 ) is a potent greenhouse gas, and wetlands represent the largest natural source of atmospheric CH 4 . Modeling of wetland-methane f...
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2023
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| Online Access: | http://www.osti.gov/servlets/purl/1573358 https://www.osti.gov/biblio/1573358 https://doi.org/10.2172/1573358 |
| Summary: | The main objective of the project was to improve predictions of future CH 4 emissions from natural wetlands. This objective was motivated by the fact that methane (CH 4 ) is a potent greenhouse gas, and wetlands represent the largest natural source of atmospheric CH 4 . Modeling of wetland-methane feedbacks indicates that wetland methane emissions could drive 21 st century climate change, with global wetland emissions matching or exceeding anthropogenic emissions by 2100 (Zhang et al., 2017). However, modeled estimates of wetland CH 4 emissions have high variability, which reflects a lack of mechanistic and predictive understanding of the processes and interactions that control methane production, oxidation and emissions from wetlands. The project focused specifically on wetlands within boreal regions that form when permafrost thaws, because warming temperatures have (Poulter et al., 2017) and will continue (Zhang et al., 2017) to increase wetland methane emissions from this region by promoting permafrost thaw and creating new wetland area. The accomplished aims listed below advanced mechanistic understanding of how vascular vegetation and other factors (such as early spring rainfall and time since permafrost thaw) influence methane production, oxidation and emission from boreal wetlands, and thus, assisted in the successful achievement of the project’s main objective of improving predictions of future CH 4 emissions. The project undertook multiple different approaches, including fieldwork, a laboratory plant-growth study, porewater stable-carbon-isotope calculations, and numerical modeling of the wetland methane cycle. Accomplished Aim 1) Quantified rates of microbial carbon transformation in peatland soils and gained mechanistic understanding of how site factors, such as time since permafrost thaw, influence rates of microbial production and oxidation of methane. Accomplished Aim 2) Identified two novel roles for rain in the methane cycle — transporting thermal energy into bogs, which increases methane ... |
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