|
|||||
|
|
Seafloor bioalteration of sulfide minerals: results from in situ incubation studies |
|
| Authors: | Katrina J Edwards Thomas M McCollom Peter R Buseck |
| Institution: | 1 Geomicrobiology Group, Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, McLean Lab, MS 8, Woods Hole, MA 02536, USA 2 Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392, USA 3 Department of Earth and Planetary Sciences, The University of New Mexico, Albequerque, NM 87131-1116, USA 4 Biochemistry, Arizona State University, Tempe, AZ 85287-1404, USA |
| Abstract: | We present results of incubation studies conducted at low temperatures (∼4°C) in the vicinity of a seafloor hydrothermal vent system. We reacted Fe-, S-, Cu-, and Zn-bearing minerals including pyrite, marcasite, chalcopyrite, sphalerite, elemental sulfur, and a portion of a natural chimney sulfide structure for 2 months at the Main Endeavour Segment of the Juan de Fuca Ridge in the Pacific Ocean. Our study utilizes Fluorescent In Situ Hybridizations (FISH), Scanning and Transmission Electron Microscopy (SEM, TEM), and light microscopic analysis. The surfaces of these minerals are solely colonized by Bacteria and not by Archaea. Colonization densities vary over an order of magnitude with the following sequence: elemental sulfur > chimney sulfide > marcasite > pyrite > sphalerite > chalcopyrite, and correspond well with the abiotic oxidation kinetics of these materials, excepting elemental sulfur, which is both the least reactive to oxidizing species and the most heavily colonized. Colonization densities also correspond with apparent degree of reaction (dissolution pitting + accumulation of secondary alteration products). Heavy accumulations of secondary Fe oxides on Fe-bearing minerals, most notably on the chimney sulfide, form in situ as the result of mineral dissolution and the activity of neutrophilic Fe-oxidizing bacteria. Results suggest that mineral-oxidizing bacteria play a prominent role in weathering of seafloor sulfide deposits, and that microbial utilization of mineral substrates contributes to biomass production in seafloor hydrothermal environments. |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ | |