HR: 0800h
AN: V51C-1504    [Abstracts]
TI: Heterotrophic Fe-Oxidizing Bacteria Associated With Basalt Surfaces Supporting Life On Vailulu'u Seamount, American Samoa
AU: * Haucke, L
EM: lhaucke@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, mail code:0202, San Diego, CA 92109 United States
AU: Templeton, A
EM: alexis.templeton@colorado.edu
AF: University of Colorado, Boulder, Department of Geological Sciences Campus Box 399, 2200 Colorado Ave, Boulder, CO 80309 United States
AU: Bailey, B
EM: bebailey@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, mail code:0202, San Diego, CA 92109 United States
AU: Tebo, B
EM: btebo@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, mail code:0202, San Diego, CA 92109 United States
AU: Staudigel, H
EM: hstaudigel@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, mail code:0202, San Diego, CA 92109 United States
AB: Fe, the fourth-most abundant element in the Earth's crust, is also one of the most biologically essential ones. The reduced form, Fe(II), is often considered to be biologically limiting as a result of its low solubility and rapid chemical oxidation to Fe(III)(hydr)oxides at circumneutral pH. The alteration of basaltic glass, enriched in Fe(II), however, provides an abundant supply of reduced iron and, thus, has a major influence on local ocean chemistry and Fe bioavailability. Despite the fact that chemical Fe(II) oxidation takes place very rapidly, we demonstrate that alteration processes of freshly formed basaltic glass can be crucially enhanced by microbial activity.Cultivation of bacteria from basalt surfaces collected from two active submarine volcanoes, Loihi (Hawaii) and Vailulu'u (American Samoa) show a large number of heterotrophic bacteria capable of oxidizing Fe(II) and that these bacteria. not only enhance basalt dissolution but also play a major role in precipitating large amounts of thick Fe(hydr)oxides mats on Vailulu'u Seamount, particularly in the vicinity of low temperature hydrothermal vents. These mats contain substantial quantities of organic carbon that may serve as food sources for some of the macrobiological life on Vailulu'u Seamount. This very prominently includes a substantial population of eels that is found in close spatial association with up to 1m thick Fe oxide/microbial mat at Nafanua volcano, a recent volcanic cone that grew from the crater floor of the seamount. Microbial community analysis on different substrates ranging from basalt surfaces to microbial mats were performed on specially designed culturing media for detection and isolation of heterotrophic bacteria capable of Fe(II)-oxidation. Clone libraries from microbial mats originating from an eel dominated area of Vailulu'u crater are being compared to libraries made from eel guts in order to provide information to what extent these mats are being used as a food source in otherwise nutrient poor and extreme habitats like volcanic seamounts and their hydrothermal systems.
DE: 8412 Reactions and phase equilibria (1012, 3612)
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005