Characterizing progression of aerobic degradation of Paleozoic petroleums in Indiana soils using molecular ratios and carbon isotopic signatures
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：Sarah R. Pietraszek-Mattner.
- 分类号：a875.4
- ISBN：0496959395(ebk.) :
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02h0029368 20120612095503.0 cr un||||||||| 120611s2004 xx ||||f|||d||||||||eng | 3162258 0496959395(ebk.) : CNY371.35 NGL NGL NGL a875.4 Pietraszek-Mattner, Sarah R. Characterizing progression of aerobic degradation of Paleozoic petroleums in Indiana soils using molecular ratios and carbon isotopic signatures [electronic resource] / Sarah R. Pietraszek-Mattner. 2004. 1 v. : digital, PDF file. Adviser: Pratt, Lisa M. Thesis (Ph.D.)--Indiana University, 2004. Geochemical changes during advanced stages of aerobic microbial degradation of crude oils are well established in the literature, but few studies document geochemical changes during the onset of degradation. Three crude oils from Devonian reservoirs in the Illinois and Michigan basins were degraded under both field and laboratory conditions in order to assess molecular and isotopic indicators of initial to moderate degradation. The field experiment utilized a natural setting in Indiana and entailed shallow burial of oil-doped limestone tablets in soil with a thick and relatively uniform B zone for over 900 days. No detectable changes (initial stage) in buried oils occurred during the first 180 days. Reduced concentration or complete loss of n-alkanes <； C15 and shifts to higher pristane/nC 17 and phytane/nC18 values (minor degradation) were the dominant changes from 180 days to 300 days. Distinct changes in relative abundance of aliphatic, aromatic, and polar fractions, further decreasing abundance of n-alkanes, and further increasing pristane/ nC17 and phytane/nC18 values (light degradation) were evident after 300 days of field burial. During laboratory experiments, Devonian-reservoired oils were degraded in a microcosm containing a nutrient mixture, a known quantity of crude oil, and a community of hydrocarbon-degrading microbes enriched from a local oil seep. After 45 days, n-alkanes were completely removed and the concentrations of isoalkanes were substantially reduced (moderate degradation). In both field and laboratory degradation experiments, Devonian-reservoired oils from the Michigan basin began degrading earlier than similar oils from the Illinois basin, with this difference more pronounced in laboratory experiments compared to field experiments. Positive isotopic shifts of up to 1.5&permil； were documented during degradation for individual n-alkanes in the range of nC15 through nC29. Distinct isotopic maxima occur around n C15 and nC28 with an intervening minimum at nC22 to nC23 . Systematically varying isotopic shifts in n-alkanes have not been documented previously, indicating an unexpected degree of molecular specificity for microbial attack on n-alkanes during initial to moderate degradation. Biodegradation Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=KG7lxeMEHbQ%3d NGL Bs1466 rCNY371.35 ; h1 bs1204