HR: 1340h
AN: B13A-1054    [Abstracts]
TI: Biogeochemistry of Phosphorus Exchange in Magnetic Bacteria
AU: * Drennen, C
EM: cdrennen@usc.edu
AF: University of Southern California, 5601 Trousdale PKWY Dept. of Earth Sciences ZHS 119, Los Angeles, CA 90089-0740 United States
AU: Popa, R
EM: rpopa@usc.edu
AF: University of Southern California, 5601 Trousdale PKWY Dept. of Earth Sciences ZHS 119, Los Angeles, CA 90089-0740 United States
AU: Nealson, K
EM: knealson@usc.edu
AF: University of Southern California, 5601 Trousdale PKWY Dept. of Earth Sciences ZHS 119, Los Angeles, CA 90089-0740 United States
AB: Magnetotactic bacteria swim (some at high relative speeds of ~5 mm/min) across the sediment water interface, in both freshwater and marine ecosystems, this occurs in an apparent diurnal pattern. We hypothesized that this is part of a migratory life cycle across the oxic anoxic transition zone (OATZ), at the water-sediment interface. Magnetotactic bacteria have been shown to contain sizable reserves of metals, phosphorus and sulfur. If the migration model is true, then this migration has important consequences on the exchange of phosphorous, sulfur and metals between water and sediments. Our results show that the exchange of phosphorus between magnetic bacteria and water is consistent with a periodic life cycle. These results also show that magnetic cells accumulate large amounts of phosphate under oxidizing conditions. Under reducing and anaerobic conditions (e.g. sulfidic, low Eh sediments) cells release phosphorus. This research shows the importance of magnetic bacteria in the exchange of materials across redox interfaces. Magnetotactic bacteria may also play a significant role in biomineralization and bioweathering of metal oxides and phosphates, as well as possibly contributing to the magnetization of sediments.
DE: 0330 Geochemical cycles (1030)
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0419 Biomineralization
DE: 0448 Geomicrobiology
DE: 1030 Geochemical cycles (0330)
SC: Biogeosciences [B]
MN: Fall Meeting 2005