The Argonne National Laboratory Subsurface Biogeochemical Research Program Science Focus Area: Wetland Hydro-Biogeochemistry


Kenneth Kemner1* ([email protected]), Pamela Weisenhorn1, Maxim Boyanov1,2, Daniel Kaplan3, Dien Li3, Brian Powell4, Angelique Lawrence5, Christopher Henry1, Ted Flynn6, Man-Jae Kwon7, Yiran Dong8, Odeta Qafoku9, Alice Dohnalkova9, Ravi Kukkadapu9, Rosalie Chu9, Carlo Segre10, Cara Santelli11, Crystal Ng11, Martial Taillefert12, Jeff Catalano13, Daniel Giammar13, Peter Santschi14, Clara Chan15, Edward J. O’Loughlin1


1Argonne National Laboratory, Lemont, IL; 2Bulgarian Academy of Sciences, Sofia, Bulgaria; 3Savannah River National Laboratory, Aiken, SC; 4Clemson University, Clemson, SC; 5Florida International University, Miami, FL; 6California Department of Water Resources, Sacramento, CA; 7Korea University, Seoul, Korea; 8China University of Geosciences, Wuhan, China; 9EMSL, Pacific Northwest National Laboratory, Richland, WA; 10Illinois Institute of Technology, Chicago, IL; 11University of Minnesota–Twin Cities, Minneapolis/St. Paul, MN; 12Georgia Technical University, Atlanta, GA; 13Washington University, St. Louis, MI; 14Texas A&M University–Galveston, TX; 15 University of Delaware, Newark, DE



Within wetlands, water movement and biogeochemically catalyzed transformations of its constituents determine the mobility of nutrients and contaminants, emission of greenhouse gasses into the atmosphere, carbon (C) cycling, and water quality itself. The long-term objective of the Argonne Wetland Hydro-Biogeochemistry science focus area (SFA) is the development of a mechanistic understanding and ability to model the coupled hydrological, geochemical, and biological processes controlling water quality in wetlands and the implications of these processes for watersheds commonly found in humid regions of the United States. To accomplish this, the Argonne Wetland Hydro-Biogeochemistry SFA focuses research on a riparian wetland within Tims Branch at the Savannah River Site. Tims Branch contains riparian wetlands representative of those commonly found in humid regions of the Southeast that have C-rich soils and high iron (Fe) content. However, it is unique in that parts of the watershed received large amounts of contaminant metals and uranium from previous industrial-scale manufacturing of nuclear fuel and target assemblies. Groundwater and surface water level monitoring wells have been installed to provide hydrological context (e.g., gaining versus losing stream conditions) to the study sites within the watershed. Understanding the function of wetlands in relation to hydrologic exchange, including the concentration of nutrients and contaminants within the soluble and particulate components of groundwater and surface waters, addresses the goal of the ESS Program to advance a robust, predictive understanding of watershed function.

The overarching research hypothesis is that hydrologically driven biogeochemical processes that create redox dynamic conditions from the nanometer to meter scales are major drivers of groundwater and surface water quality within riparian wetland environments. Researchers identified three major components, or focus areas, of the Tims Branch riparian wetland that represent critical zones containing hydrologically driven biogeochemical drivers that control water quality: sediment, rhizosphere, and stream. Within these three focus areas, researchers identified two common thematic knowledge gaps that inhibit the ability to predict controls on water quality: (1) in-depth understanding of the molecular-scale biogeochemical processes that affect Fe, C, and contaminant speciation within the wetland sediment, rhizosphere, and stream environments and (2) in-depth understanding of hydrologically driven biogeochemical controls on the mass transfer of Fe, C, and contaminants within wetland sediment, rhizosphere, and stream environments. Holistically addressing hypotheses related to these two knowledge gaps organizes the SFA in its development of a hydro-biogeochemical conceptual model of the Tims Branch riparian wetland.