HR: 0800h
AN: V51C-1505    [Abstracts]
TI: Iron Oxidizing and Reducing Bacteria as Contributors to Basaltic Glass Colonization and Subsequent Weathering in Active Hydrothermal Vent Systems on Loihi and Vailulu'u Seamounts
AU: * Bailey, B
EM: bebailey@ucsd.edu
AF: UCSD/Scripps Institution of Oceanography, 9500 Gilman Dr. M/C 0225, La Jolla, CA 92093 United States
AU: Templeton, A
EM: alexis.templeton@colorado.edu
AF: University of Colorado, Department of Geological Sciences Campus Box 399, 2200 Colorado Ave University of Colorado, Boulder, CO 80309-0399 United States
AU: Haucke, L
EM: lhaucke@ucsd.edu
AF: UCSD/Scripps Institution of Oceanography, 9500 Gilman Dr. M/C 0225, La Jolla, CA 92093 United States
AU: Staudigel, H
EM: hstaudigel@ucsd.edu
AF: UCSD/Scripps Institution of Oceanography, 9500 Gilman Dr. M/C 0225, La Jolla, CA 92093 United States
AU: Tebo, B M
EM: btebo@ucsd.edu
AF: UCSD/Scripps Institution of Oceanography, 9500 Gilman Dr. M/C 0225, La Jolla, CA 92093 United States
AB: The extreme oligotrophic nature of the oceanic crust was once believed to be an inhospitable environment to support microbial life. However, numerous studies in the past two decades have revealed diverse chemolithotrophic microbial communities inhabiting the deep biosphere within the oceanic crust. Vailulu'u Seamount in American Samoa and Loihi Seamount in Hawai'i provide access to the deep biosphere environments through the study of the interaction of hydrothermal vent water, basaltic substrates and microbial communities. Both seamounts have been found to exhibit similar iron-encrusted microbial mats surrounding both high and low temperature hydrothermal vent orifices. We are targeting iron as the main electron donor/acceptor in these environments due to the relative abundance and availability in basalts. Through the use of the HURL Pisces submersibles, we exposed amended basaltic glasses of several different compositions to a host of different environments on both seamounts in order to study the colonization and biofilm characteristics of the microbial communities. A large culturing effort reveals multiple iron oxidizing and reducing bacteria as members of the microbial community responsible for the colonization and subsequent dissolution and alteration of basaltic glass. We employ an annular reactor to expose the same suite of chemically altered basaltic glasses to a sample of iron microbial mats taken from Vailulu'u to provide a laboratory complement the environmental exposure experiments. Here cell counts reveal a 90% enhanced colonization and growth on the basalt glass versus the surrounding epoxy and borosilicate glass. The ability of microbes to leach nutrients (such as iron) out of the host substrate has far reaching astrobiological implications for nutrient sources available to sustain life in a Mars or Europa biosphere.
DE: 0448 Geomicrobiology
DE: 0450 Hydrothermal systems (1034, 3017, 3616, 4832, 8135, 8424)
DE: 0463 Microbe/mineral interactions
DE: 5220 Hydrothermal systems and weathering on other planets
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005