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http://hdl.handle.net/11375/13572
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DC Field | Value | Language |
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dc.contributor.advisor | Warren, Lesley | en_US |
dc.contributor.author | Elliott, Amy V. C. | en_US |
dc.date.accessioned | 2014-06-18T17:04:26Z | - |
dc.date.available | 2014-06-18T17:04:26Z | - |
dc.date.created | 2013-10-07 | en_US |
dc.date.issued | 2013-10 | en_US |
dc.identifier.other | opendissertations/8408 | en_US |
dc.identifier.other | 9492 | en_US |
dc.identifier.other | 4675225 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/13572 | - |
dc.description.abstract | <p>This doctoral research comparatively assesses the biogeochemical properties of suspended aquatic flocs through a integrated field-laboratory approach; providing new insight into the linkages among floc associated bacteria, floc-reactive solid phases and trace metal uptake.</p> <p>Results show flocs to possess a distinct geochemistry, microbiology and composition from bed sedimentary materials in close proximity (III-oxyhydroxide minerals (FeOOH); resulting in localized floc-Fe-mineral precipitates and enhanced reactivity. Further, the Fe-enrichment of floc and of floc bio-mineral constituents in turn provides an important and novel lens through which to examine how environmental microbial communities, microbial metabolism and Fe<sup>III</sup>/Fe<sup>II </sup>redox transformations interact. The results were the discovery of floc-hosted, Fe<sup>III/II</sup>-redox cycling bacterial consortia across diverse oxygenated (O<sub>2</sub><sup>Sat.</sup>=1-103%) aquatic systems, which were not predicted to sustain bacterial Fe-metabolism. Both environmental<em> </em>and experimentally-developed consortial aggregates constituted multiple genera of aero-intolerant Fe<sup>III</sup>-reducing and Fe<sup>II</sup>-oxidizing bacteria together with oxygen consuming organotrophic species. These findings highlight that the implementation of geochemical thermodynamic constraints alone as a guide to investigating and interpreting microbe-geosphere interactions may not accurately capture processes occurring <em>in situ.</em></p> <p><em> </em> Seasonal investigation of microbial Fe<sup>III/II</sup>-redox transformations highlighted the interdependence of floc Fe-redox cycling consortia members, revealing that cold conditions and a turnover in putative Fe-reducing community membership extinguishes the potential for coupled Fe-redox cycling by wintertime floc bacteria. Further, the observed summer-winter seasonal turnover of <em>in situ</em> floc community membership corresponded with an overall shift from dominant Fe to S redox cycling bacterial communities. This significantly impacted observable floc Fe and TE (Cd, Pb) geochemistry, resulting in a shift in floc associated Fe-phases from dominantly Fe<sup>(III)</sup><sub>(s) </sub> to Fe<sup>(II)</sup><sub>(s)</sub>, and, in turn, corresponded to a large decrease of TE uptake by flocs under ice.</p> | en_US |
dc.subject | biogeochemistry | en_US |
dc.subject | geomicrobiology | en_US |
dc.subject | iron oxidizing bacteria | en_US |
dc.subject | iron reducing bacteria | en_US |
dc.subject | floc | en_US |
dc.subject | trace metal behaviour | en_US |
dc.subject | Biogeochemistry | en_US |
dc.subject | Environmental Microbiology and Microbial Ecology | en_US |
dc.subject | Geochemistry | en_US |
dc.subject | Microbial Physiology | en_US |
dc.subject | Biogeochemistry | en_US |
dc.title | THE GEOMICROBIOLOGY OF SUSPENDED AQUATIC FLOCS: LINKS BETWEEN MICROBIAL ECOLOGY, FE(III/II)-REDOX CYCLING, & TRACE ELEMENT BEHAVIOUR | en_US |
dc.type | thesis | en_US |
dc.contributor.department | School of Geography and Geology | en_US |
dc.description.degree | Doctor of Science (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Size | Format | |
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fulltext.pdf | 29.99 MB | Adobe PDF | View/Open |
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