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Filtering by: Creator Colwell, Frederick Remove constraint Creator: Colwell, Frederick Degree Field Microbiology Remove constraint Degree Field: Microbiology

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  • The effects of X-ray CT scanning on microbial communities in sediment cores

    Creator:
    Ewton, Erica
    Abstract:
    Using X-ray computed tomography (CT) scanning to characterize the physical characteristics of soil and sediment cores allows scientists to observe and analyze stratigraphy without destroying the integrity of different layers. Microbiologists often work with geologists to characterize the microbial communities in such cores; however, X-rays are known to be destructive...
    Resource Type:
    Honors College Thesis
    Full Text:
    . Abstract approved:_____________________________________________________ Frederick Colwell

  • Comparing Sediment Microbial Communities of Arctic Beaver Ponds to Tundra Lakes and Streams

    Creator:
    Shannon, Kelly
    Abstract:
    In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into pan-Arctic tundra ecosystems. It is unknown how the advance of beavers into Arctic watersheds will impact microbial communities responsible for the mineralization of organic matter (OM), which has implications for carbon cycling. To...
    Resource Type:
    Masters Thesis
    Full Text:
    Abstract approved: ______________________________________________________ Frederick Colwell In

  • Construction of a model organism for performing calcium carbonate precipitation in a porous media reactor

    Creator:
    Kaufman, Megan J.
    Abstract:
    Aquifers are an important storage location and source of fresh groundwater. They may become polluted by a number of contaminants including mobile divalent radionuclides such as strontium-90 which is a byproduct of uranium fission. A method for remediating such divalent radionuclides is sequestration through co-precipitation into calcium carbonate. Calcium carbonate...
    Resource Type:
    Masters Thesis
    Full Text:
    in a Porous Media Reactor Abstract approved: Frederick S. Colwell Aquifers are an important

  • Microbial Community Dynamics of an Aquifer Biostimulated to Precipitate Calcite

    Creator:
    Ohan, Juliette
    Abstract:
    Microbial-induced calcite (CaCO₃) precipitation (MICP) is a well-known natural phenomenon where microbes precipitate calcite in their environment as a result of metabolic activity. It has recently been of interest as a bioengineered technique to stabilize soils for construction applications. A known metabolic pathway to induce MICP is ureolysis, where introduced...
    Resource Type:
    Masters Thesis
    Full Text:
    : ______________________________________________________ Frederick S. Colwell Microbial-induced calcite (CaCO3) precipitation (MICP) is a well

  • Microbiology of basalts targeted for deep geological carbon sequestration : field observations and laboratory experiments

    Creator:
    Lavalleur, Heather J.
    Abstract:
    With rising concentrations of CO₂ in the Earth's atmosphere causing concern about climate change, many solutions are being presented to decrease emissions. One of the proposed solutions is to sequester excess CO₂ in geological formations such as basalt. The deep subsurface is known to harbor much of the microbial biomass...
    Resource Type:
    Masters Thesis
    Full Text:
    Sequestration: Field Observations and Laboratory Experiments Abstract approved: Frederick S. Colwell

  • Establishment and dynamics of methane-oxidizing microbial communities in marine sediments

    Creator:
    Klasek, Scott A.
    Abstract:
    Marine sediments are vast sources and reservoirs of methane, a potent greenhouse gas. Most of this methane is anaerobically oxidized by archaea before it can reach the overlying ocean, though the efficiency of this process often depends on methane fluxes and mechanisms of fluid transport. Anaerobic methanotrophic archaea, or ANME,...
    Resource Type:
    Dissertation
    Full Text:
    : ____________________________________________________________ Frederick S. Colwell Abstract Marine sediments are vast sources and reservoirs of methane

  • Biogeochemical Processing of Freshwater Carbon in the Anthropocene

    Creator:
    Buser, Jessica Z.
    Abstract:
    Freshwater systems cycle carbon along a spatial and temporal biogeochemical continuum, across which ecosystem processes contribute to transformations of organic matter (OM). Various ecological constraints impact rates OM transformation and production and consumption of the energetic end of respiration, methane. Microbiological processing and complete reduction of carbon substrates to methane...
    Resource Type:
    Dissertation
    Full Text:
    Anthropocene Abstract approved: ______________________________________________________ Frederick S

  • Bioinformatics applied to freshwater cyanobacterial blooms and cyanophage

    Creator:
    Schwartz, Andrew D.
    Abstract:
    Freshwater cyanobacterial blooms are a nuisance and health threat in the Pacific Northwest. The accepted methods of characterizing these blooms by microscopic cell counts cannot differentiate between toxic and non-toxic strains of the cyanobacterium Microcystis. Also, there is limited understanding of freshwater cyanophage that may control bloom dynamics. In order...
    Resource Type:
    Masters Thesis
    Full Text:
    . Dreher Frederick S. Colwell Freshwater cyanobacterial blooms are a nuisance

  • Microbial diversity, metabolic potential, and transcriptional activity along the inner continental shelf of the Northeast Pacific Ocean

    Creator:
    Bertagnolli, Anthony D.
    Abstract:
    Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of...
    Resource Type:
    Dissertation
    Full Text:
    . Giovannoni, Dr. Peter J. Bottomley, Dr. Frederick Cowell, Dr. Allen Milligan and Dr. Kaichang Li Past and

  • Symbiotic and saprophytic characteristics of a soil population of Rhizobium leguminosarum bv. trifolii

    Creator:
    Yap, Kathryn H. M.
    Abstract:
    Although much has been learned about the comparative nodulating behavior of simple mixtures of rhizobial strains under non-soil situations, it is unclear how these findings relate to the factors influencing nodulation success by the complex mixtures of strains found within soil-borne rhizobial populations. Information on the structure and physiological behavior...
    Resource Type:
    Masters Thesis
    Full Text:
    (Johnson et al., 1965; Ireland and Vincent, 1968; Holland, 1970; Weaver and Frederick, 1974). Ironically