Master of Science (MS)
Oceanography and Coastal Sciences
Adenosine triphosphate (ATP) is a unique biochemical indicator of active microbial biomass and its relationship to environmental conditions. Its assay in sediments is complicated, however, by adsorptive loss to the sediment matrix and subsequent interferences in the luciferin-luciferase assay by compounds released during the extraction process. Corrections must be applied to correct for these losses and we describe a novel approach using radioactive ATP to correct for ATP adsorption. The sediment matrix also plays a significant role in determining both the magnitude of the ATP pool and the extent of the ATP adsorptive loss. Coarser sediments were found to have greater ATP levels and little adsorption, whereas silts and clays had significantly lower ATP levels and up to 95% adsorptive loss. Application of the ATP assay to very fine-grained marine sediments in off shore oil producing areas revealed a sedimentary ATP biomass of approximately 40ngg-1 prior to oil development but after drilling the ATP level dropped 10 to 15 fold to 2 to 3 ngg-1. Post-drill sediments contained high levels of barium which is associated with drilling fluids, and had no detectable oxygen at a depth of 3mm, and the mean grain size decreased indicating the bottom was being coated over by the drill spoils.
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Guilbeau, Eric Tyson, "The effects of sediment grain size and oil exploration on microbial ATP biomass" (2003). LSU Master's Theses. 321.
Paul A. LaRock