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Effect of Hydrological Forcing on the Biogeochemical Transformation of Carbon and Greenhouse Gas Emissions in Riparian and Streambed Sediments

Active Dates 9/1/2021-8/31/2024
Program Area Environmental Systems Science
Project Description
Effect of Hydrological Forcing on the Biogeochemical Transformation of Carbon and Greenhouse Gas Emissions in Riparian and Streambed Sediments

Martial Taillefert (Principal Investigator), Chloe Arson, Thomas J. DiChristina (Co-Investigators), Georgia Institute of Technology
Kenneth M. Kemner, Argonne National Laboratory SFA (Co-Investigator)
Daniel I. Kaplan, Savannah River National Laboratory (Co-Investigator)
Christa Pennacchio, JGI (Unfunded co-investigator)
Stephen J. Callister, EMSL (Unfunded co-investigator)

Biogeochemical processes in wetland sediments regulate the transformation and exchange of carbon, nutrients, and greenhouse gases (GHGs) with surface waters and thus influence water quality. In fact, streams and wetlands are responsible for a large fraction of global GHG emissions despite constituting a relatively small surface area. Wetlands are terrestrial-aquatic interfaces (TAIs) where water movement creates strong gradients and heterogeneities that are microbially highly variable and influenced by temporal variations in precipitation, temperature, and stream discharge. These hydrological variations create hot spots and moments that are difficult to quantify and account for in reactive transport models (RTMs) that are used to make predictions of GHG emissions. As a result, conventional RTMs often misrepresent GHG emissions from wetland sediments. In our previous SBR exploratory project we developed new microbial equations for RTMs that rely on the activity of microbial communities to identify hidden reactions and more accurately describe microbial competition processes.

In the proposed project, we will apply these new equations in the field to: 1) predict the role of hydrological conditions on the transformation of carbon, nutrients, and biogeochemical processes in wetland sediments; and 2) determine the effect of these processes on GHG emissions. State-of-the-art in situ physical and geochemical measurements with high spatiotemporal resolution will be combined with meta-omic (i.e., meta-genomic, -transcriptomic, -proteomic, and -metabolomic) signals of the active microbial populations. The new microbial equations will be integrated in new RTMs that will be combined with machine-learning algorithms to assess model sensitivity and calculate production and consumption rates of GHGs and other relevant species. Characterizing the distribution of the main geochemical species in wetland sediments with high spatial and temporal resolution will provide unique insights into the processes that control GHG emissions from wetland sediments. The newly developed models will predict how hydrological variations, competition between microbial processes, and changes in sediment properties over time affect carbon and nutrient cycling as well as GHG emissions at TAIs. Ultimately, these efforts will capture the role of sediment heterogeneities in GHG emissions.

Characterizing and predicting the dynamics of carbon transformation processes and GHG emissions in wetland sediments in response to hydrological fluctuations is relevant to the ESS mission and applicable to other environments of interest to ESS, such as permafrost and tropical sediments. This project will also contribute to the WHONDRS and IDEAS-watershed programs by disseminating samples, datasets through ESS-DIVE, and new reaction and geomechanics modules for incorporation into community-based models. The interdisciplinary research team consists of geochemists, modelers, and microbiologists with expertise in high spatiotemporal geochemical measurements, reactive transport modeling, and multi-omics that will complement the synchrotron and field capabilities of the ANL SFA and benefit from JGI and EMSL expertise.
Award Recipient(s)
  • Georgia Tech Research Corporation (PI: Taillefert, Martial)