HR: 09:45h
AN: B11A-07    [PDF]
TI: Modeling the Influence of Transport on Chemical Reactivity in Microbial Membranes: Mineral Precipitation/Dissolution Reactions.
AU: * Felmy, A R
EM: ar.felmy@pnl.gov
AF: Pacific Northwest National Laboratory, Mail Stop K8-96 PO Box 999, Richland, WA 99352 United States
AU: Liu, C
EM: chongxuan.liu@pnl.gov
AF: Pacific Northwest National Laboratory, Mail Stop K8-96 PO Box 999, Richland, WA 99352 United States
AU: Clark, S
EM: sb.clark@wsu.edu
AF: Department of Chemistry Washington State University, One SE Stadium Way, Pullman, WA 99164-4630 United States
AU: Straatsma, T
EM: tp.straatsma@pnl.gov
AF: Pacific Northwest National Laboratory, Mail Stop K8-96 PO Box 999, Richland, WA 99352 United States
AU: Rustad, J
EM: rustad@geology.ucdavis.edu
AF: Department of Geology University of California-Davis, One Shields Avenue, Davis, CA 95616 United States
AB: It has long been known that microorganisms can alter the chemical composition of their immediate surroundings and influence such processes as ion uptake or adsorption and mineral precipitation dissolution. However, only recently have molecular imaging and molecular modeling capabilities been developed that begin to shed light on the nature of these processes at the nm to um scale at the surface of bacterial membranes. In this presentation we will show the results of recent molecular simulations of microbial surface reactions and describe our efforts to develop accurate non-equilibrium thermodynamic models for the microbial surface that can describe ion uptake and surface induced mineral precipitation. The thermodynamic models include the influence of the bacterial electrical double layer on the uptake of ions from solution and the removal, or exclusion, of ions from the surface of the cell, non-equilibrium diffusion and chemical reaction within the membrane, as well as a new thermodynamic approach to representing ion activities within the microbial membrane. In the latter case, the variability in the water content within the microbial membrane has a significant influence on the calculated mineral saturation indices. In such cases, we will propose the use of recently developed mixed solvent-electrolyte formalisms. Recent experimental data for mixed-solvent electrolyte systems will also be presented to demonstrate the potential impact of the variable water content on calculated ion activities within the membrane.
DE: 0400 Biogeosciences
DE: 0614 Biological effects
SC: Biogeosciences [B]
MN: 2003 Fall Meeting