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Title: Final Technical Report (DE-SC0010338) Methane Oxidation in the Rhizosphere of Wetland Plants

Abstract

The main objective of the project was to improve predictions of future CH4 emissions from natural wetlands. This objective was motivated by the fact that methane (CH4) is a potent greenhouse gas, and wetlands represent the largest natural source of atmospheric CH4. Modeling of wetland-methane feedbacks indicates that wetland methane emissions could drive 21st century climate change, with global wetland emissions matching or exceeding anthropogenic emissions by 2100 (Zhang et al., 2017). However, modeled estimates of wetland CH4 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 predictionsmore » of future CH4 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 emissions by warming soils and increasing plant and microbial productivity, and transporting oxygen into bogs, which decreases methane emissions by facilitating methane oxidation. Accomplished Aim 3) Assessed the effects that hallow aerenchyma tissue in vascular plants has on methane production, oxidation and emission in thaw bogs. Accomplished Aim 4) Determined the impacts that belowground allocation of carbon by plants has on methane production, oxidation and emission in thaw bogs Accomplished Aim 5) Created and tested a dynamic and climate-sensitive representation of rhizospheric methane oxidation for large-scale wetland models. The project addressed one of the scientific drivers for the Biological and Environmental Research program at DOE: “discovering the physical, chemical, and biological drivers and environmental impacts of climate change.” It did so by both advancing fundamental understanding of the how vascular vegetation and other key factors (e.g., early spring rainfall and time since permafrost thaw) affect methane production, oxidation and transport within permafrost-thaw bogs and by generating a more realistic representation of rhizospheric methane oxidation for regional-scale wetland models. Project outcomes have progressed knowledge ofr how future shifts in both climate variables (like rainfall amount and timing) and plant behavior (like species composition and productivity) will alter methane emissions in wetlands, improving the scientific community’s ability to produce more robust predictions of future methane emissions and climate–methane feedbacks.« less

Authors:
ORCiD logo [1]
  1. University of Washington
Publication Date:
Research Org.:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23). Climate and Environmental Sciences Division
OSTI Identifier:
1573358
Report Number(s):
DOE-UW-10338
DOE Contract Number:  
SC0010338
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Neumann, Rebecca. Final Technical Report (DE-SC0010338) Methane Oxidation in the Rhizosphere of Wetland Plants. United States: N. p., 2019. Web. doi:10.2172/1573358.
Neumann, Rebecca. Final Technical Report (DE-SC0010338) Methane Oxidation in the Rhizosphere of Wetland Plants. United States. doi:10.2172/1573358.
Neumann, Rebecca. Thu . "Final Technical Report (DE-SC0010338) Methane Oxidation in the Rhizosphere of Wetland Plants". United States. doi:10.2172/1573358. https://www.osti.gov/servlets/purl/1573358.
@article{osti_1573358,
title = {Final Technical Report (DE-SC0010338) Methane Oxidation in the Rhizosphere of Wetland Plants},
author = {Neumann, Rebecca},
abstractNote = {The main objective of the project was to improve predictions of future CH4 emissions from natural wetlands. This objective was motivated by the fact that methane (CH4) is a potent greenhouse gas, and wetlands represent the largest natural source of atmospheric CH4. Modeling of wetland-methane feedbacks indicates that wetland methane emissions could drive 21st century climate change, with global wetland emissions matching or exceeding anthropogenic emissions by 2100 (Zhang et al., 2017). However, modeled estimates of wetland CH4 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 CH4 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 emissions by warming soils and increasing plant and microbial productivity, and transporting oxygen into bogs, which decreases methane emissions by facilitating methane oxidation. Accomplished Aim 3) Assessed the effects that hallow aerenchyma tissue in vascular plants has on methane production, oxidation and emission in thaw bogs. Accomplished Aim 4) Determined the impacts that belowground allocation of carbon by plants has on methane production, oxidation and emission in thaw bogs Accomplished Aim 5) Created and tested a dynamic and climate-sensitive representation of rhizospheric methane oxidation for large-scale wetland models. The project addressed one of the scientific drivers for the Biological and Environmental Research program at DOE: “discovering the physical, chemical, and biological drivers and environmental impacts of climate change.” It did so by both advancing fundamental understanding of the how vascular vegetation and other key factors (e.g., early spring rainfall and time since permafrost thaw) affect methane production, oxidation and transport within permafrost-thaw bogs and by generating a more realistic representation of rhizospheric methane oxidation for regional-scale wetland models. Project outcomes have progressed knowledge ofr how future shifts in both climate variables (like rainfall amount and timing) and plant behavior (like species composition and productivity) will alter methane emissions in wetlands, improving the scientific community’s ability to produce more robust predictions of future methane emissions and climate–methane feedbacks.},
doi = {10.2172/1573358},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {11}
}