5. Peridotite Dissolution Rates in Microbial Enrichment Cultures1

Jennifer A. Josef,2 Martin R. Fisk,3 and Stephen Giovannoni4

ABSTRACT

Using peridotite drilled during Ocean Drilling Program Leg 209, a series of enrichment cultures were initiated on board the ship to stimulate microbially enhanced dissolution of olivine. Dissolution was estimated by measured changes in dissolved Li and Si in the media through time (up to 709 days). The results suggest that there was no significant difference between the amounts of dissolved Li and Si in most of the inoculated microbial cultures compared to the control cultures. Alternative explanations for this are that

  1. No microbes are living in the culture tubes that can affect the dissolution rates of olivine,
  2. The control cultures have microbes effecting the dissolution of olivine as well as the inoculated cultures,
  3. Not enough time has passed to build up a large enough microbial population to effect the dissolution of the olivine in the culture tubes,
  4. Microbes act to suppress dissolution of olivine instead of enhancing dissolution, and
  5. Abiotic dissolution overshadows microbially enhanced dissolution.

Further work is required to test these alternatives.

1Josef, J.A., Fisk, M.R., and Giovannoni, S., 2007. Peridotite dissolution rates in microbial enrichment cultures. In Kelemen, P.B., Kikawa, E., and Miller, D.J. (Eds.), Proc. ODP, Sci. Results, 209: College Station, TX (Ocean Drilling Program), 1–38. doi:10.2973/odp.proc.sr.209.002.2007

2Bruce Museum of Arts and Science, 1 Museum Drive, Greenwich CT 06830-7100, USA. jjosef@brucemuseum.org

3College of Ocean and Atmospheric Sciences, Oregon State University, 104 COAS Administration Building, Corvallis OR 97331-5503, USA.

4Department of Microbiology, Oregon State University, 104 COAS Administration Building, 222 Nash Hall, Corvallis OR 97331-5503, USA.

Initial receipt: 7 November 2005
Acceptance: 22 January 2007
Web publication: 6 July 2007
Ms 209SR-002

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