HR: 0800h
AN: ED51D-0043    [Abstracts]
TI: Simulation of a Hyporheic Environment to Determine the Microbial Effects in Estuarine Groundwater Systems
AU: * Nguyen, K
EM: kn2008@barnard.edu
AF: Dept. of Chemistry; Barnard College, 3009 Broadway, New York, NY 10027 United States
AU: Kujawinski, E B
EM: ekujawinski@whoi.edu
AF: Dept. of Marine Chemistry & Geochemistry; Woods Hole Oceanographic Institution, 360 Woods Hole Rd. MS #25, Woods Hole, MA 02543 United States
AU: Mailloux, B J
EM: bjm2103@columbia.edu
AF: Columbia Earth Institute, 535 W. 116th St., New York, NY 10027 United States
AB: Microorganisms in aquatic environments play a fundamental role in determining the chemical composition of their surroundings. Our experiment focused on the hyporheic zone and the chemistry of groundwater discharged to estuaries. A flow-through column simulation of a hyporheic zone was used to monitor the effects due to the bacteria living in sediment. Artificial groundwater was amended with isotopically-labeled acetate (13C-acetate) to stimulate microbial activity. Groundwater parameters were monitored in the effluent after flowing through the aquifer sediment. Increased microbial activity was inferred from the decreased effluent acetate concentration, the presence of iron(II) in the effluent and increased bacterial phospholipid concentrations in sediment. The results indicate that changes in groundwater chemistry can be linked to microbial activity in the subsurface. Further analysis of microbial activity under differing nutrient limitations will be conducted to more fully understand the changes in groundwater composition.
DE: 4805 Biogeochemical cycles (1615)
DE: 4806 Carbon cycling
DE: 4815 Ecosystems, structure and dynamics
SC: Education and Human Resourcese [ED]
MN: 2004 AGU Fall Meeting