One of our main foci during the last decade has been the development of an internationally recognized integrated multidisciplinary scientific team focused on the investigation of fundamental biogeochemical questions. Presently, expertise that is represented by members of the team includes x-ray Physics, Environmental Chemistry, Environmental Microbiology, (Bio)geochemistry, and radiolimnology. Additional expertise in electron microscopy, x-ray microscopy, Microbial Ecology, and Bioinformatics often is provided by collaborations with scientists outside of our group.
In addition to investigating fundamental Biogeochemical transformations resulting from biological, physical, and chemical processes in the subsurface that affect the transformations and mobility of carbon/nutrient forms, contaminants, and the geochemical character of groundwater, we facilitate the use of the Advanced Photon Source and other synchrotrons to do work closely related to research within the Argonne Subsurface Biogeochemical Research Program Science Focus Area. Information about how to apply for General User Beam time at the Advanced Photon Source can be found at the Advanced Photon Source web site or by contacting Ken Kemner.
It is currently difficult to predict the biogeochemical cycling of elements in the subsurface. Understanding the coupled biological, chemical, and physical processes controlling elemental cycling in the environment is of fundamental importance to advance a robust predictive understanding of Earth’s climate and environmental systems and to inform the development of sustainable solutions to the Nation’s energy and environmental challenges. Bacteria and the extracellular material associated with them are thought to play key roles in determining an element’s chemical speciation and its mobility in the environment. Additionally, the microenvironment at and adjacent to actively metabolizing cells can be significantly different from the bulk environment. Our group uses a number of analytical techniques (i.e. ICP-AES, HPLC, kinetic phosphorescence analysis, x-ray diffraction, electron microscopy, etc.) and “now” generation high-throughput sequencing and bioinformatics approaches to better understand the role of minerals, microbes, and microbial communities in determining elemental cycling in the environment. Additionally, we make use of a number of synchrotron-based x-ray techniques to further our understanding of the processes occurring at physical, geological, chemical, and biological interfaces that affect these transformations. Hard x-ray absorption spectroscopy techniques such as extended x-ray absorption fine structure (EXAFS) spectroscopy, x-ray absorption near edge spectroscopy (XANES), and nonresonant inelastic x-ray scattering (NIXS) can provide information on the local chemical environment, coordination, and valence of individual elements in soils and sediments. Additionally, hard x-ray micro-imaging techniques (i.e. x-ray fluorescence microscopy and x-ray microtomography) enable investigation of complex environmental samples at the needed micron and submicron length scales. An important advantage of these techniques results from their utility in investigating environmental materials in their natural, and often hydrated, state.