HR: 0800h
AN: H21A-0994    [Abstracts]
TI: Bacterial Community Structure Response to Petroleum Concentration in Groundwater
AU: * Kitts, C L
EM: ckitts@calpoly.edu
AF: Environmental Biotechnology Institute Cal Poly State University, 1 Grand Ave Biological Sciences Department, San Luis Obispo, CA 93407 United States
AU: Wrighton, K C
EM: kwrighto@calpoly.edu
AF: Environmental Biotechnology Institute Cal Poly State University, 1 Grand Ave Biological Sciences Department, San Luis Obispo, CA 93407 United States
AU: Phillips, W A
EM: waphilli@calpoly.edu
AF: Environmental Biotechnology Institute Cal Poly State University, 1 Grand Ave Biological Sciences Department, San Luis Obispo, CA 93407 United States
AU: Cano, R J
EM: rcano@calpoly.edu
AF: Environmental Biotechnology Institute Cal Poly State University, 1 Grand Ave Biological Sciences Department, San Luis Obispo, CA 93407 United States
AU: Lundegard, P D
EM: plundeg@unocal.com
AF: Unocal Corporation, 376 S. Valencia Ave, Brea, CA 92823 United States
AB: This study characterized the bacterial community present in groundwater samples from the Guadalupe Dunes Restoration Project on the central California coast. The purpose of the study was to determine the changes in bacterial community structure and function in response to variations in the concentration of dissolved phase total petroleum hydrocarbons (TPH) in groundwater plumes at the site. For the purpose of this study groundwater samples were collected at varying distance from TPH source zones in 10 different plumes. All samples were analyzed for ammonia, phosphate, TPH, methane, oxygen, carbon dioxide, nitrate, sulfate, and dissolved iron levels. Chemical analysis revealed that the groundwater chemistry varied between plumes and on a well-to-well basis within a plume. Principle component analyses (PCA) demonstrated that TPH degradation related parameters explained 28% of the variation in the groundwater chemistry. In addition to the physical and chemical analyses, four liters of each groundwater sample were filtered and bacterial DNA was isolated to determine the relationship between groundwater chemistry and bacterial community structure and function. Specific Polymerase Chain Reaction (PCR) primers were used to characterize populations of Eubacteria, and Archaea, as well as function genes for sulfate reducing, methanotrophic, and methanogenic bacteria. Terminal Restriction Fragment (TRF) Length Polymorphisms (or T-RFLP) were used to analyze community structure. Eubacterial and Archaeal groundwater communities were separated into distinct clusters which did not clearly reflect changes in groundwater chemical parameters unless individual plumes were analyzed separately. However, specific Eubacterial and Archaeal TRF peaks did correspond to known petroleum degrading organisms and methanogenic bacteria, respectively. Only one sample produced a positive result for the sulfite reductase gene (dsrAB), indicating that sulfate reduction may not be a dominant process at the site. While the particulate methane monooxygenase gene (pmoA) was not detected in all samples, the specific type of pmoA gene present in a sample correlated directly to methane concentration, indicating that different types of methanotrophic bacteria are affected by changes in groundwater chemistry. In contrast to the methanotroph data, the presence of different types of the methyl coenzyme M reductase gene (mcrA) specific for methanogens did not correlate to physical and chemical groundwater parameters.
DE: 1803 Anthropogenic effects
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting