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Nitrogen: Both A Potential Stimulator And Suppressor Of Cyanobacterial Blooms In Temperate Lakes, Catherine Goltz
Nitrogen: Both A Potential Stimulator And Suppressor Of Cyanobacterial Blooms In Temperate Lakes, Catherine Goltz
Theses and Dissertations (Comprehensive)
Cyanobacterial blooms are complex phenomenon that are impacted and controlled by various factors such as lake depth, air temperature, wind, and nutrient loading. Nutrients such as phosphorus, nitrogen and iron all have very differing effects on cyanobacterial blooms. While phosphorus and iron are known to drive cyanobacterial biomass, nitrogen has been observed to have a direct impact on toxin synthesis. Nitrogen exists in the environment in many different forms such as atmospheric N2, in inorganic forms such as nitrate and ammonium as well as in organic forms such as urea which can all affect cyanobacterial bloom development differently. …
Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker
Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker
All Dissertations
Uranium (U) released from the M-Area at the Department of Energy Savannah River Site into Tims Branch, a seasonal wetland and braided stream system, is estimated to be 43,500 kg between 1965 and 1984. The motivation for this work is the uranium’s persistence in the wetland for decades, where it is estimated that 80% of the U currently remains in the Tims Branch wetland. U has begun to incorporate into wetland iron (Fe) and carbon cycles, associating with local Fe mineralogy and deposits of rich wetland organic matter (OM). The objective of this work is to characterize the chemical phases …
Determination Of Iron-Reducing Bacterial Activities In Lake Sediments., Alexandra Kahn
Determination Of Iron-Reducing Bacterial Activities In Lake Sediments., Alexandra Kahn
Williams Honors College, Honors Research Projects
Algal blooms are growing rampantly in lacustrine systems due to an increase of phosphorus, a nutrient for algae. Phosphorus is being released into the environment causing overpopulation and eutrophication which damages the ecosystem. The availability of phosphorus is affected by the solubility of iron which is regulated through iron reducing and iron oxidizing bacteria. Phosphorus adheres to insoluble Fe(III), which prohibits algae from utilizing it, while phosphorus does not attach to soluble Fe(II) and therefore it remains available to algae. The purpose of this study was to determine how bacteria influence iron solubility and what are the ideal environmental conditions …
Enabling High Quality Oxygen Measurements During Robotic Based Studies Of Ocean Ecological And Biogeochemical Processes, Brianna A. Alanis
Enabling High Quality Oxygen Measurements During Robotic Based Studies Of Ocean Ecological And Biogeochemical Processes, Brianna A. Alanis
Theses and Dissertations
Dissolved oxygen is an essential parameter necessary for understanding marine ecological and biogeochemical processes. New robotic vehicles and autonomous platforms are being applied to an even wider range of ecological and biogeochemical studies. Thus, arises the opportunity for matching the best possible oxygen sensing techniques and methods to these new platforms. In so doing, we can enable both more targeted and higher resolution oxygen measurements than previously possible and potentially use oxygen measurements for a wider range of applications, including in situ incubation experiments and primary productivity measurements. This thesis tested three different oxygen sensors in a trade study for …
Iron Reduction In Soot, Hector Casique
Iron Reduction In Soot, Hector Casique
All Master's Theses
Ferrous iron (Fe(II)) has been implicated as one contributor in the generation of reactive oxygen species (ROS) from ambient particles emitted during the incomplete combustion of fossil and biomass fuels. Although ROS are known to induce unhealthy oxidative stress in cellular systems, the mechanisms of Fe(II) formation and stabilization in aerosol particles are still not well understood. Here, we investigate the role of soot on Iron reduction from Fe(III) to Fe(II), under various conditions including those encountered in the tailpipe of a vehicle. Aqueous leaching experiments of soot-hematite mixtures were carried out while analyzing for Fe(II) spectrophotometrically, and changes in …
Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson
Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson
Electronic Theses and Dissertations
For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this …
Restoration Of Headwater And Coastal Fens In The Lake Superior Basin Of Upper Michigan, James A. Bess
Restoration Of Headwater And Coastal Fens In The Lake Superior Basin Of Upper Michigan, James A. Bess
Dissertations, Master's Theses and Master's Reports - Open
In 2009, research projects were initiated at Michigan Technological University to develop restoration techniques for headwater fens and coastal wetlands in the southern Lake Superior Basin in Michigan’s Upper Peninsula. The primary focus of these was to quantify the efficacy of using locally collected seeds as a technique for wetland restoration. Two primary sites were selected, the Sleeper Lake Fen complex in Luce County and the Portage Waterway-Keweenaw Bay region of Lake Superior in Baraga and Houghton Counties. At the Sleeper Lake site, a combination of heavy machinery, seeding and mulch application was used to restore a 1.6 km ditch …
Effect Of Sediment Slurry Application On Selected Aspects Of Sulfur, Iron, And Manganese Biogeochemistry In A Coastal Louisiana Marsh, Martin Kyle Maxwell
Effect Of Sediment Slurry Application On Selected Aspects Of Sulfur, Iron, And Manganese Biogeochemistry In A Coastal Louisiana Marsh, Martin Kyle Maxwell
LSU Master's Theses
Coastal wetlands, long recognized to be among the most productive ecosystems on the planet, are being lost at a disturbingly high rate in coastal Louisiana due to both eustatic sea-level rise and land subsidence. A number of approaches have been proposed for reducing wetland loss and restoring deteriorated wetlands, among which the addition of sediment to increase marsh surface elevation is promising. However, little is known about how the added sediment affects the biogeochemistry of marsh sediment. The objective of this study was to determine the effects of sediment slurry addition on sulfur, iron, and manganese biogeochemistry in a subsiding …
Mobility Of Plutonium In Zea Mays (Corn): Determination Of Transport Velocities, Spatial Distribution And Correlations With Iron., Shannon Thompson
Mobility Of Plutonium In Zea Mays (Corn): Determination Of Transport Velocities, Spatial Distribution And Correlations With Iron., Shannon Thompson
All Dissertations
Understanding the environmental behavior of plutonium (Pu) is essential for proper radioactive waste disposal or for remedial activities following an accidental release of Pu. The environmental behavior of Pu is influenced by physical, chemical, and biotic factors, such as the simultaneous existence of multiple Pu species, redox transformations at mineral surfaces, colloid formation, and the potential of microbes and plants to affect its sorption to soil. Plant Pu studies have been conducted for quantifying bioaccumulation or phytoremediation. Until now, experimental studies have not focused on the capacity of plants to affect the transport behavior and distribution of Pu in the …