Biogeochemical evidence for microbial community change in a jet fuel hydrocarbons-contaminated aquifer

A glacio-fluvial aquifer located at Wurtsmith Air Force Base, MI, had been contaminated with JP-4 fuel hydrocarbons released after the crash of a tank er aircraft in October of 1988. Microbial biomass and community structure, associated with the aquifer sediments, were characterized based on the anal ysis of phospholipid ester-linked fatty acids (PLFA). Fatty acids ranged fr om C-12-C-20 in carbon chain length, including saturated, monounsaturatsd, branched, and cyclopropyl fatty acids. Polyunsaturated fatty acids were vir tually absent from the aquifer sediments. These findings suggested that bac teria were dominant organisms within the aquifer microbial communities. The total microbial biomass and community composition in aquifer sediments, as determined by PLFA analysis, varied with depth, and between locations at s imilar depths, indicating considerable microbial heterogeneity in the subsu rface. PLEA patterns in the hydrocarbon-contaminated anaerobic zones indica ted higher microbial biomass and metabolically more diverse microbial commu nities than those in aerobic zones. (C) 1998 Elsevier Science Ltd. All righ ts reserved.