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Full-Text Articles in Physical Sciences and Mathematics
Calcite Spherulite Formations And Their Controls In Halophilic Bacterial Cultures, Zakaria Jibrin
Calcite Spherulite Formations And Their Controls In Halophilic Bacterial Cultures, Zakaria Jibrin
UNLV Theses, Dissertations, Professional Papers, and Capstones
This study arose from an accidental discovery of calcite spherulites forming on colonies of various halophilic bacteria grown on solid Luria-Bertani medium made containing water from a brine pool in Death Valley, their natural habitat. Further studies with a large spherulite forming bacteria, Pseudoalteromonas haloplanktis, showed that calcite precipitation conditions were the consequence of bacteria using amino acids as a source of carbon and energy, a metabolism that produces NH3 and CO2 waste products. NH3 raises the pH of the medium, turning CO2 into CO32-. Calcium in the natural brine combines with CO32-. The resulting spherulitic calcite precipitation is nano-acicular …
Quantification Of Organic Carbon Sequestered By Biogenic Iron Sulfide Minerals In Long-Term Anoxic Laboratory Incubations, Nader Nabeh, Cheyenne Brokaw, Aude Picard
Quantification Of Organic Carbon Sequestered By Biogenic Iron Sulfide Minerals In Long-Term Anoxic Laboratory Incubations, Nader Nabeh, Cheyenne Brokaw, Aude Picard
Life Sciences Faculty Research
Organic carbon sequestration in sedimentary environments controls oxygen and carbon dioxide concentrations in the atmosphere. While minerals play an important role in the preservation of organic carbon, there is a lack of understanding about the formation and stability of organo-mineral interactions in anoxic environments, especially those involving authigenic iron sulfide minerals. In this study, we quantified organic carbon and nitrogen sequestered in biogenic iron sulfide minerals co-precipitated with sulfate-reducing bacteria (SRB) in freshwater and marine conditions in long-term laboratory experiments. The amounts of C and N associated with biogenic iron sulfide minerals increased with increasing cell biomass concentrations available in …