John Bargar | Environmental Molecular Sciences Laboratory

Fiber Optic Sensor for Microscale Monitoring of Nitrate and Oxygen in the Rhizosphere

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

Joshua Torgeson

We propose to develop a fiber sensor capable of continuous, in situ, spatially-resolved, simultaneous nitrate and dissolved oxygen measurements within the rhizosphere in tandem with oxygen optode…

Redox controls on uranium mobility: the role of natural organic matter transformations

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

John Bargar

Project type

Special Science

Natural organic matter (NOM) profoundly influences the cycles of metals in the subsurface in its role as electron donor for bacteria and as a complexing agent. In the proposed work, we investigate…

Impact of natural organic matter on U speciation and mobility in groundwater

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

John Bargar

Project type

Exploratory Research

Uranium (U) contamination of aquifers is a persistent problem at DOE legacy ore processing sites and, contrary to initial predictions, many plumes are not attenuating with natural groundwater…

Biogeochemical controls exerted by organic-rich sediments on carbon cycling and uranium mobility

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

John Bargar

Project type

Large-Scale EMSL Research

Floodplains are hydrologically and biogeochemically dynamic environments that store extensive quantities of carbon, host diverse ecosystems, and serve as interfaces for nutrient and contaminant…

Influence of rhizosphere processes on biogeochemical cycles governing metal contaminant mobility in floodplains

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Kristin Boye

Project type

Large-Scale EMSL Research

Floodplains are important repositories for metals, regulating their transport to surface and groundwater. The heterogeneous lithology and seasonal wet-dry cycling associated with alluvial deposits,…

Microbial metabolic activity and biogeochemical reaction networks in redox cycled alluvial systems

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Kristin Boye

Project type

FICUS Research

Redox conditions and related switches in microbial metabolic activities exert primary control over the stability of carbon, nutrient, and contaminant stocks in alluvial systems, such as floodplains…

Role of Ca in Organic Matter Preservation

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Sharon Bone

Project type

Large-Scale EMSL Research

Calcium can play a major role in the preservation of carbon in the subsurface due to its ability to participate in cation bridging. Ca2+ can link together two negatively charged moieties, such as two…

A Colloid is Born: Understanding iron-rich colloid genesis and transformation for improved watershed biogeochemical models

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Kristin Boye

Project type

Large-Scale EMSL Research

Interfaces between subsurface layers of floodplains are ‘hot spots’ for thriving biogeochemical activity and exchange, owing to distinct compositional and permeability/porosity differences between…

MONet Data Management and Access Gateway

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Yuri Eberlim de Corilo

We will develop, implement, and deploy the backend software necessary to manage, store, and serve as the gateway to make the MONet data findable, accessible, interoperable, and reusable (FAIR). In…

Synthesis of photoactive metal oxide films for study using time-resolved x-ray techniques

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Kelly Gaffney

Project type

Large-Scale EMSL Research

We propose to study cuprous oxide thin film growth and expand the scope of the work to other transition-metal-oxide systems. Transition-metal oxides have many interesting photophysical and…

Transformation Mechanisms and Kinetics of Fe-(oxyhydr)oxide Reduction and their Impact on Uranium Sequestration

Lead Institution

Stanford Linear Accelerator Center

Principal Investigator

Juan Lezama Pacheco

Project type

Large-Scale EMSL Research

Redox cycling of Fe-(oxyhydr)oxides such as ferrihydrite in naturally or artificially reduced sediments has a major impact on the speciation and stability of uranium. Ferrihydrite is a poorly…

Influence of organic carbon on molecular-scale biogeochemical cycling of iron, sulfur, and uranium in organic-rich aquifer sediments

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

John Bargar

Project type

Large-Scale EMSL Research

We propose a SLAC-EMSL collaboration to study the biogeochemical coupling of subsurface natural organic matter (NOM) to iron, sulfur, and uranium redox cycles in the subsurface at the DOE-BER funded…

Projects