Temporal dynamics of CO2 and CH4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Earth and Biological Sciences Directorate
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). National Security Directorate
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environment Directorate
Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedent moisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. The objective was to understand shifts in biogeochemical processes in response to changing soil moisture, based on soil respiration and methane production rates, and to elucidate such responses based on the observed electron acceptor and metabolite profiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidence that soil redox was the principal factor driving metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of their concentrations in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction compared to carbon loss due to methanogenesis. These results show that extended and short-term saturation created conditions conducive to increasing metabolite availability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast, extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- AC05-76RL01830; 1619948
- OSTI ID:
- 1439016
- Alternate ID(s):
- OSTI ID: 1390570; OSTI ID: 1698174
- Report Number(s):
- PNNL-SA-123359; 50052
- Journal Information:
- Ecological Engineering, Vol. 114, Issue C; ISSN 0925-8574
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Spectral analysis of continuous redox data reveals geochemical dynamics near the stream–aquifer interface
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journal | November 2018 |
Effects of Tidal Scenarios on the Methane Emission Dynamics in the Subtropical Tidal Marshes of the Min River Estuary in Southeast China
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journal | August 2019 |
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