Nutrient limitation and microbially mediated chemistry: Studies using tuff inoculum obtained from the Exploratory Studies Facility, Yucca Mountain
Flow-through bioreactors are used to investigate the relationship between the supply (and limitation) of major nutrients required by microorganisms (C, N, P, S) and effluent chemistry to obtain data that can be useful to develop models of microbially mediated aqueous chemistry. The bioreactors were inoculated with crushed tuff from Yucca Mountain. Six of the 14 bioreactor experiments currently in operation have shown growth, which occurred in as few as 5 days and as much as a few months after initiation of the experiment. The value of combining detailed chemical and microbial community analyses, long-duration experiments, and abiotic chemical models to distinguish chemical patterns is evident. Although all of the bioreactors contain the same initial microorganisms and mineral constituents, PLFA analysis demonstrates that both input chemistry and temperature determine the character of the long-term population of microorganisms. Where microbial growth occurs, that community can have a significant impact on the water chemistry. These principles are well known, but the authors note their relevance to modeling microbially mediated chemistry. The authors recognize, in addition to microbial growth, three categories of chemical effects, each of which will require a different approach and constitutive equation(s): (1) unidirectional bacterial modification of the chemistry (i.e., pH) that is directly related to the dominance of particular species, (2) secondary impact of direct microbial modifications (i.e., increased dissolution of solids as a result of reduced pH), and (3) cyclical effects that may be attributed to internal regulation (e.g., osmoregulation or internal pH regulation) or evolution of the microbial community.
- Research Organization:
- Lawrence Livermore National Lab., CA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 20015876
- Resource Relation:
- Conference: 1998 Materials Research Society Fall Meeting, Boston, MA (US), 11/30/1998--12/04/1998; Other Information: Single article reprints are available from University Microfilms Inc., 300 North Zeeb Road, Ann Arbor, Michigan 48106; PBD: 1999; Related Information: In: Scientific basis for nuclear waste management XXII. Materials Research Society symposium proceedings: Volume 556, by Wronkiewicz, D.J.; Lee, J.H. [eds.], 1355 pages.
- Country of Publication:
- United States
- Language:
- English
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