Physical Sciences and Mathematics Commons^™

Mercury Methylation In Oxic Sub-Polar Marine Regions Linked With Nitrification, Marissa Collins Despins

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Methylmercury (MeHg) is a neurotoxin that bioaccumulates to potentially harmful concentrations in Arctic marine wildlife and in those that consume them. Monitoring and modeling MeHg bioaccumulation and biogeochemical cycling in the ocean requires understanding of the mechanisms behind net mercury (Hg) methylation. The key functional gene for Hg methylation, hgcAB, is widely distributed throughout ocean basins and spans multiple microbial phyla. While multiple microbially-mediated anaerobic pathways for Hg methylation are known, in the ocean, the majority of hgcA homologs have been found in oxic subsurface waters, in contrast to other ecosystems. In particular, microaerophilic Nitrospina, a genera of nitrite-oxidizing bacteria …

Has Winter Weather In Southwest Ohio Been Affected By The El Niño Southern Oscillation, The North Atlantic Oscillation, The Pacific Decadal Oscillation, And The Atlantic Multidecadal Oscillation?, John A. Blue

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Winter temperature and precipitation in Southwest Ohio over the last century were examined for anomalies attributable to teleconnections with large-scale atmospheric perturbations caused by the El Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO), and the Atlantic Multidecadal Oscillation (AMO). The record of temperature gives evidence of a teleconnection with the NAO, ENSO, and PDO, with the strongest link being for phases of the NAO. Most winters during positive NAO phases had mean monthly temperature warmer than the century long mean, and the majority of negative NAO phase winters had colder temperatures. The difference …

Analysis Of Amur Honeysuckle Stem Density As A Function Of Spatial Clustering, Horizontal Distance From Streams, Trails, And Elevation In Riparian Forests, Greene County, Ohio, Greg Michael Grierson Jr.

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The non-native invasive shrub Amur honeysuckle, Lonicera maackii (Rupr.) Herder (Gorchov and Trisel, 2003), is one of the most prolific invasive plant species across Midwestern and Northeastern landscapes of the United States. The locations of 2,095 individual Amur honeysuckle stems were geolocated using handheld GPS units in the understory of mixed growth forests at two study sites located approximately 5 km apart in northwestern Greene County, OH. Each site has undergone different levels of anthropogenic disturbance through time. The stem position data was used to measure the spatial clumping distribution and the density of Amur honeysuckle. The spatial clumping of …

North American Freshwater Snails As Paleoecologic Proxies In Crystal Lake, Medway, Ohio, Jaclyn R. Manker

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This study combines various paleoecological proxies found within a sediment core extracted from Crystal Lake, Medway, Ohio in order to assess the lake’s sensitivity to past climate changes and how that may have affected lake water levels. Crystal Lake is a natural kettle lake formed at the end of the Wisconsin glaciation. It is now surrounded by approximately 500 residential homes and is privately owned by the HOA of Crystal Lake. A sediment core was extracted from Crystal Lake in 2007 and has been carbon dated to 18000 years before present, indicating that it contains a complete sedimentary history from …

Sediment Nutrient Dynamics In Fondriest Agricultural Settling Pond, Marie Grace Bezold

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Excess loading of nitrogen (N) and phosphorus (P) is a serious global problem and has numerous negative impacts on water quality of aquatic ecosystems including eutrophication, harmful algal blooms, and hypoxia. Anthropogenic activities (such as the Haber-Bosch process, burning of fossil fuels, sewage treatment, and manure reuse) have led to excess N loading to aquatic systems. Sediment N dynamics were examined from Oct 2019 – Oct 2020 in an agricultural settling pond connected to a constructed wetland adjacent to an agricultural field. Intact sediment cores were amended with 15N for continuous-flow incubations to measure denitrification and N fixation rates, as …

Sediment-Water Fluxes Of Phosphorus And Trace Metals In The Maumee River, Northwest Ohio, Emily L. Holliday

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Excess phosphorus (P) and nitrogen (N) in the western basin of Lake Erie drive annual cyanobacteria blooms and associated hypoxia events. The Maumee River inputs ~5% of the water load into the western basin and ~50% of annual P loadings. I quantified seasonal variability of net P and metals fluxes from sediments in the Maumee River at four stations from Defiance, Ohio, to Maumee Bay. Upriver sediments were, on average, a total and filtered P sink throughout the year (−19 ± 7 and −6 ± 3, respectively; all fluxes represent `net flux’ reported in µmol m−2 h−1). At the river …

Internal Loading Of Nitrogen (N) And Phosphorus (P), Reduced N Forms, And Periodic Mixing Support Cyanobacterial Harmful Algal Blooms (Habs) In Shallow, Eutrophic Honeoye Lake (New York, Usa), Justin Adam Myers

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Cyanobacteria are important primary producers, but large cyanobacterial harmful algal blooms (HABs) have many negative ecological and health impacts and are becoming increasingly common. Honeoye Lake (New York, USA) is a shallow, eutrophic lake characterized by increasingly frequent HABs. Nitrogen (N) and phosphorus (P) loads often drive HABs in lakes, and sediment processes can contribute to N removal (e.g., denitrification) or loading (e.g., N fixation, remineralization). Sediment cores and lake water were collected during May–October (2016–2018) at two sites and incubated with no amendments (controls) or 15N stable isotopes to measure sediment nutrient fluxes and N cycling dynamics in Honeoye …

Quantifying Contributions To The Variance Of Permeability And Porosity Within The Western Belt Sandstones Of The Cypress Formation, Illinois Basin, Nathaniel Frederick Dulaney

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One of the strategies for reducing the emission of the greenhouse gas carbon dioxide (CO2) and mitigating its accumulation into the Earth’s atmosphere is geologic sequestration (GSCO2). This process might be paired with enhanced oil recovery (EOR) within depleted oil reservoirs to provide an economic incentive for GSCO2. Heterogeneity within reservoirs (e.g. spatial differences in entry pressure, permeability, and porosity) can exert significant influence on the dynamics of fluid flow during EOR and GSCO2, and thus on the ultimate success of GSCO2-EOR. The Western Belt sandstones of the Cypress Formation in the Illinois Basin are candidate reservoirs for GSCO2-EOR. Heterogeneity …

Community Structure Has Greater Effect On Water Column Ammonium Cycling Than Nutrients And Temperature In Shallow Lake Mesocosms, Shannon Marie Collins

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Harmful algal blooms (HABs) impact lakes worldwide and are caused by excess nitrogen (N) and phosphorus (P) loading from watersheds. Climate warming and nutrient loading effects on N cycling were examined in shallow lake mesocosms in Denmark. N loading to some mesocosms ceased in June 2018 and resumed in June 2019. Ammonium (NH4+) uptake, regeneration, and nitrification and nitrate uptake rates were evaluated. High nutrient, ambient temperature mesocosms exhibited the highest NH4+ cycling rates. Before resumption of N loading in high nutrient mesocosms, NH4+ regeneration supported 46 % of potential microbial NH4+ demand, versus 24 % with N loading. Nutrient …

Lead In Tap Water Of Public Schools Near Dayton, Ohio, Baylee Stark

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Lead (Pb) is a human-health concern, especially with regard to exposures of children. Lead contaminated drinking water is a primary route of exposure for children; however, water sampling for Pb is voluntary in schools with a public water supply. This study examined Pb in tap water from public schools around Dayton, OH. Schools were selected to span a range of ages (construction year) and community socioeconomic status. Of the 28 schools contacted, seven responded "affirmatively" to sampling, two responded "negatively", and 19 did not respond. None of the schools that were sampled had Pb concentrations exceeding the U.S. EPA guidelines …

Vegetation Sensitivity During The Mid-Holocene Warming In Western Ohio, Kristin Kopera

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There has been a growing interest in prairie reconstruction in western Ohio, yet there are few recent academic sources supporting the claim that prairies appeared in western Ohio during the mid-Holocene. The hypsithermal was the warmest and driest part of the Holocene and occurred from 8,000-4,000 years ago in the Midwest. During the hypsithermal, the Prairie Peninsula appeared from Minnesota to eastern Ohio. If prairie did appear in Ohio, it occurred during the mid-Holocene hypsithermal. The goal of this study was to determine if western Ohio experienced a prairie period during the hypsithermal using pollen as a proxy for past …

Evaluating Sediments As An Ecosystem Service In Western Lake Erie Through Quantification Of Nitrogen Cycling Pathways, Ashlynn Rose Boedecker

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Lake Erie experiences annual cyanobacterial harmful algal blooms (HABs), comprised mostly of non-nitrogen-fixing Microcystis, due to excess nitrogen (N) and phosphorus (P) inputs (eutrophication). Lake Erie's watershed is mostly agricultural, and fertilizers, manure, and drainage practices contribute to high nutrient loads. This study aimed to clarify the role of Lake Erie sediments in either exacerbating or mitigating conditions that fuel HABs via recycling and/or removal, respectively, of excess N and P. Sediment-water interface N dynamics were evaluated in low HAB (2016, dry) and high HAB (2017, wet spring and early summer) years. Intact sediment cores and overlying water were collected …

Removal Of Select Chlorinated Hydrocarbons By Nanoscale Zero-Valent Iron Supported On Powdered Activated Charcoal, Md Abu Raihan Chowdhury

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Nanoscale Zero Valent Iron (NZVI) has shown limited effectiveness in degrading chlorinated hydrocarbons (CHCs), like 1,1,1-Trichloroethane (1,1,1-TCA) and Trichloroethene (TCE), in aqueous solution. A rapid agglomeration behavior of NZVI particles due to van der waals and magnetic forces can negatively impact its overall effectiveness due to increase in particle size, and decline in CHC degradation kinetics. Different support materials, such as clays and activated carbon, have been used to stabilize NZVI particle and reduce agglomeration in aqueous solution. In this bench-scale study, NZVI supported on Powdered Activated Charcoal (PAC) was selected to prepare a composite, called PAC/NZVI, for a more …

Linking The Variance Of Permeability And Porosity To Newly Interpreted Lithofacies At The Site Of The Illinois Basin - Decatur Project, Decatur, Illinois, Ritu Chaity Ghose

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For effective geological sequestration of CO_2, it is critical to understand the processes associated with CO_2 movement and trapping in reservoirs, which requires a proper understanding of a diverse set of heterogeneous geologic properties. A highly-resolved data set from the Cambrian lower Mt. Simon sandstone reservoir (Unit A) in Decatur, Illinois, was used in a new approach to analyzing the variance of permeability and porosity. Newly interpreted bedding types, along with other factors, including grain size, and presence of bleached alterations, were considered in the analysis of variance. The results reveal that the factors contributing most to the sample variance …

Upstream Sources Inhibit Benthic Phosphorus Fluxes In The Lower Great Miami River, Southwest Ohio, Kortney Mullen

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Human activities have increased nutrient loadings to aquatic ecosystems during the past century. During low river flow in late summer and early fall, excessive concentrations of phosphorus (P) are present in the Lower Great Miami River (LGMR) and contribute to its eutrophication. Although wastewater treatment plants are suspected of being major point sources of P to the LGMR during low river flow, riverbed sediment has not been examined as an additional potential source of P. Benthic P fluxes were measured at 11 representative locations along the LGMR during late summer and early fall of 2015. Sediment and overlying water sampled …

Power Distribution And Probabilistic Forecasting Of Economic Loss And Fatalities Due To Hurricanes, Earthquakes, Tornadoes, And Floods In The United States, Scott Edward Baker

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Traditionally, the size of natural disaster events such as hurricanes, earthquakes, tornadoes, and floods is measured in terms of wind speed (m/sec), energy released (ergs), or discharge (m3/sec). Economic loss and fatalities from natural disasters result from the intersection of the human infrastructure and population with the natural event. This study investigates the size versus cumulative number distribution of individual natural disaster events in the United States. Economic losses are adjusted for inflation to 2014 United States Dollars (USD). The cumulative number divided by the time over which the data ranges is the basis for making probabilistic forecasts in terms …

Accelerated Degradation Of Chlorinated Solvents By Nanoscale Zero-Valent Iron Coated With Iron Monosulfide And Stabilized With Carboxymethyl Cellulose, Shirin Ghahghaei Nezamabadi

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Nanoscale zero-valent iron (nZVI) injections have proven to be a promising approach for the remediation of aquifers contaminated by chlorinated organic pollutants. This study compares the efficacy of nZVI in sulfidated and unamended forms in degrading selected chlorinated hyrocarbons (CHCs). Results show that nZVI amended with iron monosulfide (FeS) increases the rate of dechlorination of CT, CF and 1,1,1-TCA compared to that by unamended nZVI. The focus of this research was to characterize degradation kinetics and degradation byproduct distributions of CT, CF and 1,1,1-TCA by nZVI coated by iron monosulfide, which is represented as nZVI/FeS. To prevent nZVI particles from …

Atmospheric Effects On Radar/Ladar Detection Of Seismic Activity, Michelle Frances Via

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This thesis investigates how well ground vibrations can be detected at ladar or radar wavelengths and how the atmosphere may impact the observation of such activity. First understanding atmospheric hindrances at each of these wavelengths is helpful to prioritize by those yielding best transmission results. A prerequisite to the outdoor field experiment performed for this study involves analyzing atmospheric effects characterization at six probable wavelengths using the Laser Environmental Effects Definition and Reference tool (LEEDR) developed by the Air Force Institute of Technology's (AFIT) Center for Directed Energy (CDE). These wavelengths, selected from the shortwave infrared and microwave portions of …

Processing And Interpretation Of Illinois Basin Seismic Reflection Data, Katherine M. Gigandet

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An anonymous oil company released 2D dynamite reflection data from the Illinois basin to be reprocessed and interpreted by Wright State University. The aim of the project is to exhaustively apply different seismic processing methods to the data to determine if any improvement in the imaging and interpretation may be accomplished. The data interpretation procedure convolved extracted wavelets from the final migrated section with reflectivity calculated from well log data provided. Once major formation tops were identified attribute analysis was applied to locate potential oil volumes of interest.

The raw shot records from this impulse data are dominated by guided …

Seismic Interpretation And Well Log Analysis Of Jay County, Indiana, Focused On Lithologic Units Below The Mt. Simon Formation, Jennifer Welder

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Cuttings recovered from two Benegar wells in Jay County, Indiana, have led to the recognition of a lithic arenite and limestone layer beneath the Mt. Simon Sandstone, the regional basal sandstone of the Paleozoic platform sequence. This lithic arenite is interpreted as the Middle Run Formation which has been observed in numerous wells within the Western Ohio, Northern Kentucky, and Indiana region. However, the limestone layer in these Benegar wells is unique, with only one other instance of limestone beneath the Mt. Simon being in the Mattison #1 well in southeast Clark County, Ohio. During the summer of 2013 students …

Effect Of Land Use On Mercury In Soils Of Southwest Ohio, Rebecca L. Gamby

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Terrestrial biomass and soils are a primary reservoir of mercury (Hg) derived from natural and anthropogenic sources; however, the fate and stability of Hg in the surface soil reservoir and its susceptibility to change as a result of human activities is relatively unknown. In this study, soil concentrations of Hg and lead (Pb) were compared between old- and new-growth forest soils as well as fallow grassland and agricultural soils in southwest Ohio. Old- and new-growth forest soils had significantly greater concentrations of soil Hg, Pb, and organic matter than fallow and cultivated soils in the O/A horizon. Mercury:organic matter ratios …

Environmental Factors Affecting Methylmercury In Fish Of The Laurentian Great Lakes Region, Joel Harvey

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Monomethylmercury (MMHg) can accumulate in fish to concentrations that pose a threat to the health of fish, piscivorous organisms, and humans who eat fish. A variety of environmental factors have been hypothesized to influence either the methylation of inorganic Hg or the bioaccumulation and magnification of MMHg. This study investigates the influence of selected environmental factors on MMHg concentrations in freshwater fish across a regional scale, most of the U.S. portion of Laurentian Great Lakes region. Fish MMHg was correlated with proton deposition, sulfate deposition, nitrate deposition, mercury deposition, pH, watershed area, and Secchi depth. Only proton deposition was positively …

Copper And Nickel Partitioning With Nanoscale Goethite, Kelsey Marie Danner

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Goethite is an ideal sorbent for investigations of metal partitioning with iron oxyhydroxides because it is the most abundant iron oxyhydroxide in sediments (Langmuir, 1997; van der Zee et al., 2003), and cations have a strong affinity for goethite (Coughlin and Stone, 1995). Steady-state partitioning of nickel (Ni) and copper (Cu) to nanoscale goethite (a-FeOOH) was investigated experimentally under conditions intended to be representative of those in natural waters. Manipulated conditions included i) sorbent mass, ii) solute metal concentration, iii) reaction time, iv) pH, v) ionic strength (I), and vi) humate concentration (competitive ligand) to examine how these factors influenced …