Radiochemically-Supported Microbial Communities: A Potential Mechanism for Biocolloid Production of Importance to Actinide Transport

Affiliation(s) PI Project period Funded by
DEES Moser, Duane P. 07/01/2010 - 06/14/2013 Department of Energy

Project Description

Project Title: Radiochemically-Supported Microbial Communities: A Potential Mechanism for Biocolloid Production of Importance to Actinide Transport Objectives: 1) Characterize radiological properties of subsurface nuclear detonation cavities at the Nevada Test Site (NTS). 2) Model production of microbial substrates via radiochemical reactions and predict dominant microbial reactions from a thermodynamic perspective. 3) Employ stable isotopic characterization to track signatures of microbial vs. nucleogenic production/alteration of substrates. 4) Characterize microbial communities at nuclear detonation sites. 5) Identify dominant functional gene complement at nuclear detonation sites. 6) Develop a relevant culture collection. 7) Establish radiation-driven microcosms (proof of concept). Central Hypotheses: 1) Intrinsic radioactivity at cold war weapons testing sites mediates the abiological production of potential growth substrates for microorganisms. 2) Nucleogenic substrates are utilized by microbial communities at weapons testing sites. 3) Radiogenic biomass and biocolloids facilitate the transport of radionuclides in the subsurface. Experimental Design: Radioactive fluids will be collected in association with ongoing NTS monitoring (UGTA program) and radiological, geochemical, isotopic, and microbial characterizations conducted. Thermodynamic and radiochemical modeling will be employed to predict dominant microbial processes and potential growth yields. Molecular tools will be utilized to explore microbial diversity and identify relevant functionalities. Co-investigators/Collaborators/Vendors: Tullis C. Onstott (Princeton University, co-I), Chuck Russell (DRI, co-I); Mavrik Zavarin (LLNL, collaborator); Ken Czerwinski (UNLV, collaborator); Barbara Sherwood Lollar (University of Toronto, collaborator); Gary Andersen, (LBNL, vendor); Jizhong Zhou/Zhili He (University of Oklahoma, vendor) Impact to DOE: This proposed integrative activity endeavors to constrain the potential impact to actinide transport of recently discovered natural microbial ecosystems sustained by H2 and oxidant production resulting from the radiolysis of water. If microbial growth at DOE sites can be sustained by intrinsic radioactivity, the resulting microbial biomass, metabolites, and exudates may alter transport scenarios for radionuclides and thus represents a potentially significant (and unrealized) knowledge gap to ERSP. Support of BER Long Term Measure: If radiogenic biomass production is significant at DOE sites, the overall contribution of biological processes may be underestimated.