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dc.contributor.advisorGieg, Lisa M.
dc.contributor.authorRamos Padron, Esther
dc.date.accessioned2013-01-25T22:16:17Z
dc.date.available2013-06-15T07:01:46Z
dc.date.issued2013-01-25
dc.date.submitted2013en
dc.identifier.citationRamos Padron, E. (2013). Physiology and Molecular Characterization of Microbial Communities in Oil Sands Tailings Ponds (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/27356en_US
dc.identifier.urihttp://hdl.handle.net/11023/494
dc.description.abstractIn northern Alberta, mining operations to obtain bitumen from the oil sands generates large volumes of tailings. These are a mixture of sand, clay, water, organic solvents and residual bitumen that are deposited into old open pits, creating tailings ponds, where they are allowed to settle with the final goal of land reclamation. To speed up the sedimentation process, the addition of gypsum (CaSO4 ∙ 2H2O) is currently a management approach used bysome companies. This creates a deep watery mud line with very low oxygen permeability and enough sulfate to support the growth of anaerobic microbial communities. In this thesis work, the microbial physiology and communities associated with oil sands tailings ponds were assessed. Chemical, physiological, and molecular biology approaches were used to determine the key microbial processes (methanogenesis, sulfate reduction/oxidation), identify key substrates, and determine the dominant microbial community members in the anaerobic and aerobic zones of tailings ponds. Microbial community analysis showed that in the anaerobic zone of tailings, the sulfate-reducing/disproportionating bacterium Desulfocapsa. and the sulfide oxidizer/iron reducer Thiobacillus sp. are among the most prevalent organisms when sulfate is present. After sulfate is depleted, methanogenic Archaea become predominantly active and Methanosaeta and Methanolinea in association with Syntrophus dominate in the ponds, presumably interacting to biodegrade the available organic compounds. The residual naphtha components that constitute part of the tailings composition are the preferred electron donors in anaerobic zones (in comparison to naphthenic acids) based on enrichment culture studies. In naphtha-amended laboratory cultures, a variety of methanogens in association with Thauera sp. and Desulfocapsa sp. became enriched as the dominant organisms. Overall, microbial community composition as a function of depth in tailings ponds paralleled key iii microbial processes that were measured (sulfate reduction and methanogenesis). In the aerobic surface water, other microbes with known metabolic capabilities to degrade hydrocarbon-derived compounds such as naphthenic acids were found. The results of this work also showed that operational changes to tailings ponds shift the microbial community structure and functions. For example, pond closure resulted in a shift from a predominantly methanogenic and sulfate-reducing environment to one dominated by putative hydrocarbon degraders, indicating a positive management outcome in microbial activity associated with pond closure.en_US
dc.language.isoeng
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectMicrobiology
dc.subject.classificationOil Sands Tailings Pondsen_US
dc.subject.classificationEnvironmental Microbiologyen_US
dc.subject.classificationMicrobial Physiologyen_US
dc.titlePhysiology and Molecular Characterization of Microbial Communities in Oil Sands Tailings Ponds
dc.typedoctoral thesis
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgaryen
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/27356
thesis.degree.nameDoctor of Philosophy
thesis.degree.namePhD
thesis.degree.disciplineBiological Sciences
thesis.degree.grantorUniversity of Calgary
atmire.migration.oldid693
dc.publisher.placeCalgaryen
ucalgary.item.requestcopytrue


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University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.