Molecular-level mechanisms of microbial basalt alteration
EMSL Project ID
26704
Abstract
Basaltic glass is one of the most reactive components of the ocean crust and the high concentrations of reduced Fe and Mn it contains offers an enormous potential energy source for diverse Fe- and possibly Mn-oxidizing chemolithoautotrophs. This process could form the energetic basis for a deep subsurface biosphere and in turn, the activity of these microorganisms may significantly accelerate the rates of glass dissolution. Volcanic glasses commonly show characteristic corrosion features that are considered to be microbial in origin and although basaltic glass surfaces host diverse biological communities, little is known about the mechanisms by which these organisms contribute to weathering and the formation of alteration products. To quantify the rates and mechanisms of basalt alteration by specific metabolic group of bacteria vs. reaction with seawater alone, we have developed a new synchrotron-based, surface-sensitive x-ray scattering and spectroscopic approach that can measure on time scales of weeks to months the transfer of Fe and Mn from basaltic glasses at the nanometer scale. Here we propose investigations of basalt weathering using high-resolution techniques (FIB/SEM, TEM and cryo-TEM) to provide chemical and textural information on the nanometer to micron scale. We seek the opportunity to take the same epipolished basalt slabs that have been colonized by metal-oxidizing bacteria in both the laboratory and under deep-sea conditions to verify the extent of metal mobilization and secondary mineral information inferred from the x-ray scattering and spectroscopic data. We also intend to obtain independent information on glass hydration and bioalteration at the interface. The results of our study will contribute to our understanding of the microbe mineral interactions that affect elemental exchange and flux during water-rock interactions.
Project Details
Project type
Capability Research
Start Date
2007-09-01
End Date
2009-09-06
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Templeton, A.S., Knowles, E.J., Eldridge, D.L., Arey, B.W., Dohnalkova, A., Webb, S.M., Bailey, B.E., Tebo, B.M., Staudigel, H.S., 2009, A seafloor microbial biome hosted within incipient ferromanganese crusts. Nature Geoscience v. 2, p. 872-876