Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Relationships among geochemical processes and microbial community structure in a unique high-arsenic, sulfidic geothermal spring in Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 2007) Taylor, William 'Peyton'; Chairperson, Graduate Committee: William P. Inskeep.The metabolisms of chemotrophic microorganisms are linked with the geochemical transformation of redox-active chemical species and mineral precipitation-dissolution reactions in geothermal environments. The objectives of the current work were to correlate the spatial distribution of microbial populations with changes in aqueous geochemistry and mineralogy in a unique Yellowstone National Park (YNP) geothermal spring, and to cultivate thermophilic microorganisms with phylogenetic and metabolic relevance to spring conditions. The geothermal spring (hereafter referenced as Joseph's Coat Spring -JC3) contains the highest reported concentrations of arsenic, antimony and thiosulfate of any geothermal feature studied in YNP. A suite of analytical and molecular approaches including aqueous geochemical and dissolved gas analysis, solid phase characterization, energetic calculations, microscopy and 16S rRNA gene sequence distribution were utilized to correlate specific microbial populations with biogeochemical processes. Predominant geochemical changes observed within the outflow channel were disappearance of methane, dissolved sulfide and ingassing of dissolved oxygen. Oxidation of arsenite was significant within the outflow channel despite the slow ingassing rates of dissolved oxygen. Microbial 16S rRNA gene sequences were determined at locations in the source pool and within the outflow channel.Item Mapping changes in Yellowstone's geothermal areas(Montana State University - Bozeman, College of Agriculture, 2009) Savage, Shannon Lea; Chairperson, Graduate Committee: Rick L. Lawrence; Stephan G. Custer (co-chair)Yellowstone National Park (YNP) contains the world's largest concentration of geothermal features, and is legally mandated to protect and monitor these natural features. Remote sensing is a component of the current geothermal monitoring plan. Landsat satellite data have a substantial historical archive and will be collected into the future, making it the only available thermal imagery for historical analysis and long-term monitoring of geothermal areas in the entirety of YNP. Landsat imagery from Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) sensors was explored as a tool for mapping geothermal heat flux and geothermally active areas within YNP and to develop a change analysis technique for scientists to utilize with additional Landsat data available from 1978 through the foreseeable future. Terrestrial emittance and estimates of geothermal heat flux were calculated for the entirety of YNP with two Landsat images from 2007 (TM) and 2002 (ETM+). Terrestrial emittance for fourteen summer dates from 1986 to 2007 was calculated for defined geothermal areas and utilized in a change analysis. Spatial and temporal change trajectories of terrestrial emittance were examined. Trajectories of locations with known change events were also examined. Relationships between the temporal clusters and spatial groupings and several change vectors (distance to geologic faults, distance to large water bodies, and distance to earthquake swarms) were explored. Finally, TM data from 2007 were used to classify geothermally active areas inside the defined geothermal areas as well as throughout YNP and a 30-km buffer around YNP. Estimations of geothermal heat flux were inaccurate due to inherent limitations of Landsat data combined with complexities arising from the effects of solar radiation and spatial and temporal variation of vegetation, microbes, steam outflows, and other features at each geothermal area. Terrestrial emittance, however, was estimated with acceptable results. The change analysis showed a relationship between absolute difference in terrestrial emittance and earthquake swarms, with 34% of the variation explained. Accuracies for the classifications of geothermally active areas were poor, but the method used for classification, random forest, could be a suitable method given higher resolution thermal imagery and better reference data.Item Biogeochemical gradients and energetics in geothermal systems of Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 2006) Ackerman, Galena Gene; Chairperson, Graduate Committee: William P. Inskeep.The fate and behavior of redox-active chemical species in geothermal systems is linked with the metabolic processes of chemotrophic thermophilic microorganisms. The major goal of the current work was to perform a thorough geochemical analysis of redox active species in geothermal outflow channels, and utilize these measurements to quantify the Gibbs free energy (?Grxn) values for numerous oxidation-reduction reactions that represent potential chemolithotrophic metabolisms. Insights gained from energetic analyses can be used to structure hypotheses regarding novel microbial metabolisms and to guide cultivation strategies for isolating relevant microorganisms. A comprehensive suite of geochemical parameters, including major ions, trace elements, redox-active species and dissolved gases, were analyzed and monitored in vertical transects of 11 geothermal outflow channels in Yellowstone National Park from 2003-2005. The geothermal springs chosen for this study contained strikingly different aqueous and solid-phase geochemistry. These systems exhibited a wide range of conditions, including ranges in pH (2.7 to 7.0), temperature (60 oC to 92 oC), Cl- (0.01 to 23 mM)), SO42- (0.4 to 7.5 mM), NH4+ (0.02 to 5.7 mM), CO2 (aq) (0.1 to 4.5 mM), Fe (0.2 to 230 uM), and As (0.03 to 130 uM)Item Ecological genomics of filamentous anoxygenic phototrophic bacteria inhabiting geothermal springs in Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 2012) Klatt, Christian Gerald; Chairperson, Graduate Committee: David M. Ward.; Donald A. Bryant and David M. Ward were co-authors of the article, 'Comparative genomics provides evidence for the 3-hydroxypropionate autotrophic pathway in filamentous anoxygenic phototrophic bacteria and in hot spring microbial mats' in the journal 'Environmental microbiology' which is contained within this thesis.; Jason M. Wood, Douglas B. Rusch, Mary M. Bateson, Natsuko Hamamura, John F. Heidelberg, Arthur R. Grossman, Devaki Bhaya, Frederick M. Cohan, Michael Kuhl, Donald A. Bryant and David M. Ward were co-authors of the article, 'Community ecology of hot spring cyanobacterial mats: predominant populations and their functional potential' in the journal 'The ISME journal' which is contained within this thesis.; William P. Inskeep, Zackary Jay, Douglas B. Rusch, Susannah G. Tringe, Mary N. Parenteau, David M. Ward, Sarah M. Boomer, Donald A. Bryant and Scott R. Miller were co-authors of the article, 'Community structure and function of high-temperature phototrophic microbial mats inhabiting diverse geothermal environments' in the journal 'Geobiology' which is contained within this thesis.; Zhenfeng Liu, Marcus Ludwig, Donald A. Bryant and David M. Ward were co-authors of the article, 'Temporal patterning of in situ gene expression in uncultivated phototrophic chloroflexi inhabiting an alkaline siliceous geothermal spring' in the journal 'The ISME journal' which is contained within this thesis.The filamentous anoxygenic phototrophic bacteria (FAPs) are dominant members of many phototrophic microbial mat communities in geothermal springs. In non-sulfidic springs, FAPs are known to primarily utilize photoheterotrophic metabolism, where they incorporate organic carbon sources such as glycolate or acetate, which are byproducts of cyanobacterial metabolism. Cultures of Chloroexus aurantiacus have also been shown to be capable of photoautotrophic metabolism via the 3-hydroxypropionate pathway in culture. FAPs in non-sulfidic springs have been shown to take up bicarbonate, and this behavior is stimulated by light, H 2, and H 2S. However, previously investigated mat communities contain FAPs that are more closely related to Roseiexus spp. which have not demonstrated autotrophic growth in culture. This work aimed to i ) determine whether Roseiexus spp. isolates and uncultured FAPs contain genes necessary for autotrophy, ii ) compare the community structures of FAPs in different environments, and iii ) observe patterns in gene transcription over an entire diel period, which may indicate how these organisms physiologically acclimate to changing environmental conditions. Comparisons among multiple genomes revealed that Roseiexus spp. contain genes necessary for the 3-hydroxypropionate pathway. A metagenomic investigation of the dominant constituents of the communities in Octopus Spring and Mushroom Spring resulted in the discovery of novel phototrophic organisms. Functional attributes were assigned to eight dominant ecological guilds, including three previously unknown phototrophic bacteria belonging to Kingdoms Acidobacteria, Chlorobi, and Chloroexi. Metagenomic sequencing of six communities from diverse geochemical environments revealed the presence of FAPs and other phototrophic bacteria, however there was evidence that some FAPs were unique to particular springs. Examination of transcripts produced by FAPs inhabiting Mushroom Spring indicated that genes related to phototrophy are most highly expressed at night, which presumably allows for phototrophic metabolism in the morning. Additionally, FAPs are predicted to utilize carbon and energy storage compounds such as polyglucose, wax esters, and polyhydroxyalkanoates. Based upon the transcription profiles of relevant genes, a model of their carbon and energy metabolism is proposed. Taken together, these genomic, metagenomic, and metatranscriptomic studies have advanced the understanding of FAP diversity and both the community and physiological ecology in geothermal springs.