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Meyer, Kevin JTyphoon Impacts on the Chemical Weathering Regime and Atmospheric Carbon Consumption of a High Standing Island Watershed, Taiwan
Master of Science, The Ohio State University, 2016, Earth Sciences
The impacts of extreme weather on watershed dynamics and chemical weathering are poorly understood and rarely documented. This study addresses the impacts of Typhoon Mindulle (2004) on the physical hydrology, chemical weathering sources, and CO2 consumption of the Choshui River, a High Standing Island watershed in Taiwan. Storm-flow runoff was determined to be largely controlled by total precipitation and precipitation intensity. Watershed slope steepness is much less important in determining runoff during periods of extremely high precipitation. Weathering sources were determined to be silicate and secondary disseminated carbonate minerals at the surface and silicate contributions from deep thermal waters. Loss on ignition analysis of collected rock samples indicate disseminated carbonate may compose a greater fraction of the surface minerology than previously identified. Strontium isotope and major ion geochemistry indicate that high precipitation causes surface minerals to control the weathering profile. These data also suggest purging of silicate solute rich soil waters during storm events, creating a greater relative contribution of silicate weathering to the solute load during periods of increased precipitation and runoff. However, this leads to depletion of this solute reservoir and carbonate weathering becomes more important to the weathering regime as the storm continues. Major ion data indicate the possibility that mica weathering (muscovite, illite, biotite, chlorite) may represent an important silicate weathering pathway in the watershed, but this determination was beyond the scope of data available. Deep thermal water represents an important contribution to river solutes during lower flow conditions. Sulfuric acid creation through oxidation of pyrite was determined to be a major contributor to total weathering and represents ~40%–77% of weathering. The lowest contributions from sulfuric acid occur during peak flows. Carbonate weathering is dominant in the watershed (66%-86% of total weathering) and increases in contribution during the typhoon. The remaining chemical weathering comes from silicate materials. Carbonate weathering represents the majority of CO2 flux from the atmosphere during storm flow but silicate weathering is the majority during lower flow conditions. The carbonate contribution to CO2 flux is 36%–69% (31%–64% for silicates). Silicate weathering CO2 consumption for the 72 hours of storm sampling is 0.84 ton km-2, with a daily average of 0.28 ton km-2. CO2 flux from the atmosphere including carbonate weathering is substantially higher (2.51 ton km-2 for 72 hours storm measurements and 0.84 ton km-2 daily storm average). Chemical weathering mediated CO2 export rates from the atmosphere increased to a maximum of over 140 times the pre-storm rate for silicate weathering and 250 times the pre-storm rate for total weathering including carbonate minerals. The 72 hour sampling period contained only a portion of the total storm-flow and did not include the majority of the peak flow which occurred following sampling. Therefore, these consumption values are likely underestimated. Daily silicate consumption estimates during the storm-flow may contribute 0.03%–0.1% of average daily global silicate CO2 consumption from an area comprising ~0.001% of total global landmass for the days of storm activity. Therefore, extreme storm impacts on High Standing Islands globally may provide a significant but not represented contribution to the global carbon budget.

Committee:

Anne Carey (Advisor); W.Berry Lyons (Committee Member); Matthew Saltzman (Committee Member)

Subjects:

Atmosphere; Environmental Geology; Geochemistry; Geology; Hydrology

Keywords:

High Standing Islands; typhoons; Taiwan; weathering; carbonate; silicate; geochemistry; carbon budget; carbon consumption; strontium isotope; source mixing

Liu, TingtingWater Behavior on Olivine Surfaces
Doctor of Philosophy, The Ohio State University, 2017, Earth Sciences
Water-rock interaction is one of the most active topics in geochemistry. Olivine group as one of the most important rock-forming minerals extensively occur in the Earth's crust and the upper mantle. The stability and reactivity of olivine minerals in ambient C-H-O fluids has drawn great attention. All the complex surface and bulk reactions occurring between the mineral and surrounding fluids starts with the water on the surface. But how water molecules interact with olivine minerals on the surface on an atomistic/molecular level is still less studied. This work examines the interaction between water and olivine mineral surface, in particular, from the energetics in static state to its structure and dynamics, and vibrational properties of the water molecules on the surface, thus providing a complete picture of molecular behavior of the surface water. This investigation use computational/simulation (first-principles calculations and classical molecular dynamics simulation) tools to calculate the energetics and the dynamic properties. Neutron scattering experimental data are also used to support the dynamic and vibrational property calculations. Water molecule adsorption energy calculations via density functional theory (DFT) calculation is fulfilled by introducing different cation dopants on the forsterite(010) surface as they naturally occur in the crystal structure of olivine minerals as trace elements. It shows that Mg-H2O has the strongest adsorption energy, and the alkaline earth (AE) and transition metal (TM) cations form different types of bonding with H2O, i.e., electrostatic force dominated bonding and covalent bonding, respectively. However, there is no simple trend relating the cation dopant charge or ionic radii to the adsorption energy of water molecule. Instead, it is found that several factors, including surface lattice distortion, ionic size, lattice size (different olivine end members) can together determine the adsorption energy sequence with different metal cations. The structure and dynamics of water molecules on hydroxylated forsterite(010) surface is investigated at 270 K using classical molecular dynamics (MD) simulation. The water structure on the hydroxylated surface is composed of a first weak layer that adsorbs within the trough made by hydroxyl ions and a continuous strong layer on top of the first layer. The dynamic properties pertaining to translation and rotation were investigated separately using intermediate scattering functions (ISF). The translational diffusive motions derived by simulations qualitatively match with the fast and slow motions observed in the experiment. The rotational motion of water molecules and motions of the flexible hydrogen atoms on the surface calculated by simulations is found to be out of the observational energy window of the instrument. MD simulations and inelastic neutron scattering (INS) are used to study the vibrational behavior of water on forsterite surface. Both techniques derived a broad libration band feature by examining the first adsorbed water layer on the surface. MD simulations discover that Ow interacts with the surface Mg atom, and water molecules form an ordered Ih-like ice structure by the network of hydrogen bonding at 10 K. Simulated vibrational data at 150 K was used to compare with INS data at 10 K, avoiding the limitation of classical MD to account for quantum effects that might be significant at 10 K. Confining effect was observed by the simulations, as the molecules near to the surface exhibit smaller bending and stretching magnitude than the free molecule. This works sets up the stage for further investigation on other key geochemical process and could aid in more for water-rock reaction mechanism understanding among C-O-H fluids.

Committee:

David Cole (Advisor); Aravind Asthagiri (Committee Member); David Tomasko (Committee Member); Wendy Panero (Committee Member)

Subjects:

Geochemistry; Geology

Moore, Myles ThomasNoble Gas and Hydrocarbon Geochemistry of Coalbed Methane Fields from the Illinois Basin
Master of Science, The Ohio State University, 2016, Earth Sciences
Research presented in this thesis investigates the hydrocarbon molecular content, major and noble gas composition, the isotopic composition of noble gases and hydrocarbons, and select dissolved ions of gases and fluids from producing coalbed methane (CBM) wells. Samples were collected from the Illinois Basin in Sullivan County, Indiana. Samples analyzed in this study were compared with previously published data in the Illinois Basin to gain a greater understanding of fundamental fluid systematics and methane formation in coalbed reservoirs. Chapter 1: Conventional geochemical fingerprinting methods of hydrocarbon molecular and isotopic composition were used to determine the genetic source of natural gas in coalbed methane basins. Integration of isotopic and molecular hydrocarbon composition with noble gas geochemistry were used to determine the origin and migration of natural gas in the crust and relative role of coal seam waters and/or exogenous fluids in methane generation. Significant fluxes of exogenous thermogenic methane are observed in this coalbed methane reservoir. Chapter 2: Standard methods that assume steady state modelling and empirical methods for determining the residence time of natural gas and groundwater in coalbed methane fields using radiogenic ingrowth of 4He are compared. Previous age dating methods are corrected by taking into account significantly increased 4He diffusional rates specific to coal seams. By correcting for empirically determined rates of 4He accumulation, the geological time frame on which freshwater recharges into deeper sedimentary sequences, which may play a role in timing in which microbes are injected into coal beds and start to generate methanogenic natural gas, are more accurately constrained.

Committee:

Thomas Darrah, Dr. (Advisor); John Olesik, Dr. (Committee Chair); Frank Schwartz, Dr. (Committee Chair)

Subjects:

Chemistry; Earth; Geochemistry; Geology

Keywords:

coalbed methane; stable isotopes; natural gas; fluid migration; noble gases; post-genetic modification; residence time; crustal helium flux; exogenous fluids; thermogenic gas; helium

Yu, FangModeling of Soil Formation on The Basis of Chemical Weathering: Applications From Percolation Theory
Doctor of Philosophy (PhD), Wright State University, 2018, Environmental Sciences PhD
The concept of soil formation has been studied since the beginning of 19th century. However, until recently, there has been little concrete progress on developing an analytical result to relate soil depth or quality to measurable variables that represent the five soil-forming factors including time, parent material, topography, climate, and organisms. It has become increasingly clear that soil formation rates are closely related to chemical weathering rates. In this dissertation, we propose a theoretical approach to model soil formation process within the theoretical framework of percolation theory, which has been shown to successfully predict solute transport in heterogeneous media. From percolation theory, solute transport rate does not equal to flow rate beyond the length scale of a typical pore size, as is the case in Gaussian solute transport. Rather, it diminishes in accord with heavy-tailed solute arrival time distributions as it travels. The basis of our model relies on the hypothesis that the chemical weathering of bedrock is simultaneously the limiting factor for soil formation and most strongly limited by solute transport in porous media. To test the hypothesis, we propose a revised method to calculate Damkohler number within the same theoretical framework to evaluate the relevant importance of solute transport in limiting chemical weathering, and results imply that chemical weathering is nearly always solute transport-limited in natural media. We then examine the proposed models by comparing predictions with field data across a wide range of climatic conditions, as well as at steep topography. Results show good agreement between predictions and field observations. We also present two applications of the proposed model to geomorphology to examine the local steady-state assumption of soil and to distinguish steady and stochastic erosion process in threshold landscapes. The applications demonstrate the potential to adopt our model into geomorphological models such as landscape evolution models, and landsliding models to predict shallow landslides.

Committee:

Allen Hunt, Ph.D. (Advisor); Christopher Barton, Ph.D. (Committee Member); Mark Goltz, Ph.D. (Committee Member); W. Berry Lyons, Ph.D. (Committee Member); Thomas Skinner, Ph.D. (Committee Member)

Subjects:

Environmental Science; Geochemistry; Geomorphology

Keywords:

soil formation; chemical weathering; percolation; percolation theory

Peterman, Kenneth JamesDetermination of Oxygen Fugacity using Olivine-Melt Equilibrium: Implications for the Redox States of Mid-Ocean Ridge Basalt and Ocean Island Basalt Mantle Source Regions
Master of Science, The Ohio State University, 2017, Earth Sciences
In order to connect volcanic rocks to their mantle sources, it is essential to consider redox equilibria and their dependence on temperature, pressure, chemical composition, and oxygen fugacity. Oxygen fugacity (fO2) is an intensive variable that strongly affects the behavior of those elements in magmas that are sensitive to changes in redox state, such as Fe, and therefore Mg-Fe silicates, such as olivine. Since fO2 plays an important role in fractional crystallization, in principle, it is possible to estimate fO2 from analyses of olivine in equilibrium with the melt. This research describes a new method based on this principle called the Olivine-Melt Equilibrium Method. This method first calculates Fe3+ and Fe2+ from a relationship involving the partitioning of Mg and Fe2+ between olivine and melt. The ratio of Fe3+/Fe2+ expresses the change in the valence state of Fe, which is related to the redox state of the magma. The calculated Fe3+ and Fe2+ contents of the melt can then be used to determine the fO2 at which magma crystallized from a model described by Kress and Carmichael (1991). This model expresses a relationship between the Fe3+/Fe2+ ratio of the melt, fO2, temperature, pressure, and melt composition. The Olivine-Melt Equilibrium Method has the advantage that olivine and glass compositions are determined by an Electron Probe Micro Analyzer (EPMA), so analyzed Fe3+ and Fe2+ of the melt is not required. This is useful because glass analyses in literature typically report all Fe as ΣFeO, rather than distinguishing between Fe2O3 and FeO. Therefore, there is no need for scarce and specialized analytical methods, such as synchrotron-based techniques, to distinguish between the different oxidation states of Fe. Additionally, this method takes advantage of the fact that olivine is ubiquitous in basaltic lavas, unlike Fe-Ti oxides used to estimate fO2 from geothermometer-oxybarometers. We have calculated oxygen fugacities from published analyses of coexisting glass and olivine pairs in 982 samples from two different tectonic settings. The results (expressed as ΔFMQ) for Mid-Ocean Ridge Basalts (MORB) from the Mid-Atlantic Ridge (-1.55 ± 0.75), the East Pacific Rise (-0.65 ± 0.51), the Juan de Fuca Ridge (-0.77 ± 0.42), and the Galapagos Spreading Center (+0.08 ± 0.48) agree with results obtained using other methods and average -1.09 ± 0.89. Ocean Island Basalts (OIB) from Iceland and the Galapagos Islands (ΔFMQ = -0.43 ± 0.71 and -0.33 ± 0.35 respectively) also yield values consistent with those obtained by other methods and fall in the same range as MORB. However, lavas from the Canary Islands are more oxidized than typical MORB and OIB, with average ΔFMQ = +0.68 ± 0.52. The results for MORB and OIB potentially provide evidence for redox heterogeneity in the mantle, possibly as the result of crustal recycling. However it is necessary to evaluate the possibility that fO2 changes during magma ascent before concluding that the oxygen fugacities of erupted magmas directly reflect those of the mantle source regions.

Committee:

Michael Barton (Advisor); Berry Lyons (Committee Member); Tom Darrah (Committee Member)

Subjects:

Geochemistry; Geology; Petrology

Keywords:

Oxygen Fugacity; Olivine; Oxidation State; Igneous Petrology; Mantle; Magma; Basalt; Mid-Ocean Ridge; Ocean Island

Conte, Elise RAPPLICATIONS OF ISOTOPES TO MAGMATIC PROCESSES, ERUPTION AGES, AND NUCLEAR FORENSICS
Doctor of Philosophy, Miami University, 2017, Geology & Environmental Earth Science
This dissertation comprises four studies that apply radiogenic isotopes and 14C as primary tools to investigate problems in igneous petrology and environmental contamination. Two studies utilize uranium (U) isotopes to investigate U contamination related to the former Fernald Feed Materials Production Center (FFMPC) in southwest Ohio. Two other studies utilize Sr, Nd, Pb isotopes, U-series disequilibria and 14C to assess the magmatic evolution and timing of explosive eruptions of Sete Cidades volcano, Sao Miguel, Azores. Two studies examine the utility of tree bark for resolving the areal extent of atmospheric U contamination, using several locations in southwest Ohio that processed U. U concentrations up to ~400 times local background levels, along with progressively more depleted and enriched 235U/238U and higher 236U/238U as the FFMPC is approached, demonstrate the presence of anthropogenic U in the environment, with the minor isotope 236U serving as the most sensitive tracer. Atmospheric dispersal models demonstrate that a 5 um U-rich particle can be transported ~38 km from the FFMPC, providing a mechanism for the non-natural isotopic 236U/238U observed in Hamilton and Oxford, OH. Scanning electron microscopy revealed U-rich particles in tree bark within 1-3 km of the FFMPC. Two studies evaluate the petrogenetic processes and timescales associated with the P1-P17 deposits at Sete Cidades volcano. One study presents the first detailed petrographic, geochemical, and isotopic analyses of the Sete Cidades P1-17 eruptive products, and demonstrates that trachyte pumices from P1-P17 are primarily derived through fractional crystallization of a common parental magma, involving discrete batches of magma following distinct fractionation paths. Isotopic variations among whole rock, sanidine, and glass require the presence of xenocrystic sanidine and assimilation of small degree non-modal, partial melt of syenite wall rock similar to Sete Cidades xenoliths. The second of these studies aimed to better constrain the eruptive timing and the impact of volcanic outgassing on 14C ages. 14C data from paleosols in the P1-P17 eruptive sequence were compared to maximum ages from 226Ra-230Th disequilibria in pumices. We present the first age constraints for the P1 and P8 deposits, and further constrain the age of the P17 deposit. 14C data from modern terrestrial gastropods demonstrates the current contribution of volcanic degassing to 14C ages near volcanic centers. New ages constrain the average eruptive recurrence interval for the P1-P17 deposits at ~220 years. Together these four studies highlight the applicability of isotopic tools to a wide variety of earth systems and scenarios.

Committee:

Elisabeth Widom (Advisor); Claire McLeod (Committee Member); John Rakovan (Committee Member); Paul Tomascak (Committee Member); William Renwick (Committee Member)

Subjects:

Atmospheric Sciences; Environmental Geology; Environmental Science; Environmental Studies; Geochemistry; Geology

Keywords:

Isotope; Nuclear forensics; Environmental contamination; Fernald; Tree bark; Azores; Sete Cidades volcano; Volcanic ages; Paleosol; Gastropod; Carbon-14; U-series disequlibria

Montanye, BoChanges in biological production and lake chemistry in Lake Tanganyika over the past 400 years
Master of Science, University of Akron, 2016, Geology-Environmental Geology
Changes in lake level have had a noticeable impact on the chemistry and productivity of Lake Tanganyika, Africa. Downcore analyses of biogenic silica (BSi), organic carbon, δ15N and δ13C isotopes suggest that productivity began to decline at approximately 1750 CE with a temporary peak during a lake level increase in the late 1800s. The lake level increase of the late 1800s is marked by variations in the sedimentary record by increases in carbonate (>70%), organic carbon (>10%), and BSi (~5 wt. %). Bulk sediment δ15N, organic matter δ13C, and carbonate δ18O data generally show an inverse relationship to the BSi, organic carbon, and carbonate data in the shallow water cores during the lake level increase. One possible interpretation of this inverse relationship is that there is a shift in ecological composition of the primary producers of Lake Tanganyika to nitrogen fixers during the period of increased carbonate and lake level. As productivity began to decline again after the late 1800s lake high stand, diatoms were surpassed by nitrogen fixing phytoplankton, leading to lowered δ15N and δ13C values. Since the early 1900s, productivity of the lake has remained low at values similar to the period before the lake level increase (<3 wt. %). These observations are similar to prior work; however, my results suggest that the decline in primary production may have occurred earlier at these sites than previously inferred.

Committee:

James McManus (Advisor); John Peck (Committee Member); John Senko (Committee Member)

Subjects:

Geochemistry

Keywords:

Lake Tanganyika; geochemistry; biogenic silica; productivity; lake level change; isotopes

Philippoff, Karl StevenAn Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data
Master of Science, The Ohio State University, 2014, Geological Sciences
The interpretation of variations in oxygen isotopes ( d18O) within tropical ice core records have been a subject of much debate. In this study the ice core record from Dasuopu (28 23 N, 85 43 E) in the central Himalayas was compared with two coral composite records derived from Indian (Chagos Islands, Mafia, Mahe, Malindi, and Mayotte) and Pacific (Kiritimati, Maiana, Nauru, Palmyra, and Tarawa) Ocean corals, precipitation data from the Global Precipitation Climatology Center (GPCC) v6 and Indian monsoon subdivisions, the Nino 3.4 index, sea surface temperature (ERSST v3b), and air temperature data (NCEP 20th century reanalysis) to examine its relationship over interannual, 2-8 year, and multi-decadal timescales. Coral records represented reliable, consistent, and highly resolved proxy records of SST variability over the length of their respective records and provided a comparison for the results derived from the SST reconstructions. The results from these analyses indicate that the Dasuopu record can be best understood in a hierarchical manner. Over interannual and 2-8 year timescales, the variability of the Dasuopu oxygen isotopic record is dominated by local and regional rainfall variability which are both strongly associated with the variations in the strength of El Nino-Southern Oscillation (ENSO). However, over decadal and especially multi-decadal timescales, the variation in its isotopic record is strongly driven by long-term trends in air and sea surface temperature in regions upwind of the ice core location. These relationships were highly significant and were observed in both the coral composite and instrumental datasets, making these results more robust. A multi-regression model constructed using the summer monsoon rainfall from the East Uttar Pradesh monsoon subdivision, the summer mean Nino 3.4 index and air temperature anomalies in a region bound by 20-28 N, 80-88 E described 27% of the variance in the Dasuopu d18O record between 1886 and 1996, with temperature the most important parameter. This strongly suggests that these three parameters control a large degree of the variability observed in the Dasuopu d18O record over this time frame.

Committee:

Lonnie Thompson (Advisor); Andrea Grottoli (Committee Member); W. Berry Lyons (Committee Member)

Subjects:

Climate Change; Geochemistry; Paleoclimate Science

Keywords:

tropical ice core; coral; Himalaya; El Nino-Southern Oscillation; climate proxy; oxygen isotopes; monsoon; temperature effect; amount effect;

Al-Qattan, Nasser M E N A A Interpretation of Oxygen Isotopic Values (d18O) of North American Land Snails
Master of Science, Miami University, 2014, Geology & Environmental Earth Science
Modern land snail shells were collected along a north-south latitudinal gradient in North America, from 30°N to 58°N, to investigate the environmental controls on their oxygen isotopic composition (d18O) at a coarse spatial scale. The d18O shell composition is mainly a function of the d18O of precipitation, which gets lower at higher latitudes in response to lower air temperatures. Two exceptions were shells from two fens. The relatively low d18O shell composition from one fen was linked to the relatively negative d18O composition of groundwater. Calculations using a flux balance model for gastropod d18O suggest that the relatively high d18O shell composition from the highest-latitude fen might be related to low relative humidity conditions during the summer months when snails were active. LGM-dated shells were found to have higher d18O values than local modern shells. Using the model, this finding could be in part explained by a period of enhanced aridity, higher d18O values of the summer precipitation and/or the influence of 18O-enriched ocean waters, which is also suggested by other studies worldwide for some periods in the Pleistocene.

Committee:

Jason Rech, PhD (Committee Chair); Currie Brian, PhD (Committee Member); Yanes Yurena, PhD (Committee Member)

Subjects:

Geochemistry; Geology; Paleontology

Keywords:

Land snail shells; Stable isotope composition; Oxygen isotopes; Paleoclimate; Last Glacial Maximum; North America; Quaternary

Eyerdom, Timothy J.Treating Organic Pollutants in Urban Runoff Using Slow-Release Oxidants: Laboratory and Field Investigations
Master of Science (MS), Ohio University, 2014, Geological Sciences (Arts and Sciences)
Non-point source (NPS) contamination is a major concern for urban aquatic environments. This study tested the feasibility of using slow-release oxidants (SR-O) emplaced in storm pipes for treating organic pollutants in urban storm runoff through proof-of-concept laboratory tests and preliminary field investigations in Athens, OH. Release rates of slow-release persulfate (SR-PS), slow-release hydrogen peroxide (SR-HP), and slow-release hydroxide (SR-OH) were estimated through column tests. Results from column tests show that stable release was achieved after 100 hours of testing. Stable release for SR-HP, SR-SP, and SR-OH were up to 2.8x10-3, 5x10-1, and 2.8x10-1 mg min-1, respectively. SR-PS forms were observed to release for two weeks and at 90-100% efficiency. Total organic carbon, chloride, and sulfate concentrations in a two hour storm ranged from 9.8 to 63.4 mg L-1, 6.7 to 23.4 mg L-1, and 6.0 to 59.0 mg L-1, respectively with maximum concentrations shown in the first flush period. Since no organic pollutants were detected in the storm water, pollutant standard solutions were added to storm water samples to evaluate removal efficiencies of base activated SR-PS systems. Base activated persulfate using SR-PS, SR-HP, and SR-OH was found to be the most efficient system in treating organic pollutants within 30 minutes, the estimated residence time of storm water within storm pipes. The proof-of-concept flow-through test demonstrated that up to 60% of pollutants can be removed by the SR-PS/HP/OH within 30 minutes of reaction time in deionized water and between 25-65%, 13-36% less efficient, in storm water. Estimated Cost of using SR-O systems in urban areas can range between 109 (for 168 two hour storms) and 9908 dollars (for 168 two hour storms) per year depending on area and storm frequencies. These results suggest that installation of SR-PS/HP/OH in storm pipes could provide a novel cost effective treatment scheme for organic pollutants in urban runoff.

Committee:

Eung Seok Lee (Advisor); Dina Lopez (Committee Member); Gregory Nadon (Committee Member)

Subjects:

Geochemistry; Geological; Geology

Keywords:

Urban Runoff; Advanced Oxidation Processes; Organic Pollutants

Mukherjee, DibyenduDegradation of Chlorinated Ethenes in Mesocosms Simulating a Constructed Wetland, at WPAFB, Ohio
Master of Science (MS), Wright State University, 2008, Earth and Environmental Sciences
The main purpose of this research was to study the degradation of chlorinated ethenes in upwardflowing mesocosms, simulating a constructed wetland at Wright Patterson Air Force Base (WPAFB) in Dayton, Ohio. This research was intended to compare biogeochemical processes and PCE degradation occurring in the mesocosms and in the field site. This research also tries to look at the effects of vegetation and season on the degradation efficiency of the mesocosms. Twelve PVC column reactors were built within the greenhouse of Wright State University in September 2005 to simulate the hydraulic conditions of a constructed wetland at WPAFB. The columns were filled with wetland soils. Three kinds of wetland plants, Scirpus atrovirens (green bulrush), Carex comosa (longhaired sedge) and Eleocharis erythropoda (spike rush) were planted in nine of the reactors and three were left unplanted (control). Water samples were collected from the reactors for a period of one year and analyzed in the laboratory using a gas chromatography system (HP 6890 GC) to detect the concentration of chlorinated ethenes and methane. Degradation of PCE along with formation of the daughter products TCE, DCE, VC and Ethene were detected in the reactors. Both anaerobic and aerobic degradation processes were taking place within the reactors. Strong seasonal trends seen in the planted reactors were not so evident in the control reactors.

Committee:

Dr. Abinash Agrawal (Committee Chair)

Subjects:

Geochemistry

Keywords:

¿¿¿¿M; reactors; PCE; TCE; methane; WETLAND; ports

Baumann, Justin HThe effects of elevated temperature stress on the acquisition and allocation of carbon to lipids in Hawaiian corals
Master of Science, The Ohio State University, 2013, Geological Sciences
Understanding the complex processes of coral response to, and recovery from, bleaching events is central to our ability to predict the impacts of current and future climate change on coral reef ecosystems. Lipids are key biomolecules within the coral holobiont, serving as structural components, as well as significant energy reserves. With the frequency and intensity of bleaching events expected to rise in the coming decades, it is important to understand how coral lipids will be effected by, and recover from, bleaching. A bleaching experiment, followed by carbon pulse-chase labeling, was performed to investigate the assimilation and allocation of carbon to coral host and endosymbiont tissues (including lipids) over the course of bleaching and recovery. Here, we show that bleaching results in a decline in the allocation of photosynthetically derived carbon to lipids in the first month of recovery, but that photosynthetic carbon allocation had fully recovered after 11 months in both Porites compressa and Montipora capitata. In contrast, the allocation of heterotrophic carbon to lipids was no different between bleached and control corals in the first month for both species. While this pattern did not change after 11 months of recovery for M. capitata, dramatically higher enrichment values in the lipids built with heterotrophic carbon of bleached compared to non-bleached control Porites compressa corals were observed. This suggests that either the corals are still recovering, or that they have acclimated and are better able to resist additional bleaching. Overall, P. compressa catabolizes newly synthesized non-lipid energy reserves and maintains newly synthesized lipids. In comparison, M. capitata catabolizes heterotrophic carbon from feeding and catabolizes some of its newly synthesized lipids to meet metabolic demand while maintaining its existing lipid, protein, and carbohydrate reserves. Due to maintenance of total energy reserves and only a small (yet significant) amount of lipid catabolism, it appears that M. capitata recovers faster and may be more resilient to bleaching than P. compressa.

Committee:

Andrea Grottoli, Dr. (Advisor); Lawrence Krissek, Dr. (Committee Member); John Olesik, Dr. (Committee Member)

Subjects:

Biological Oceanography; Biology; Ecology; Geochemistry

Sulley Addo, TahiruEFFECT OF SAMPLE MISCUT ON DISSOLUTION KINETICS OF CALCITE (104) CLEAVAGE SURFACES
Master of Science (MS), Wright State University, 2013, Chemistry
Calcite is one of the most abundant naturally occurring carbonate minerals in the earth crust, and it is believe to play a crucial role in the long-term effectiveness of geochemical process works such as geological carbon sequestration. Due to the ease in which clean, flat calcite surfaces may be prepared, a lot of dissolution studies have been carried out on its (104) cleavage plane. However in geologic media, natural calcite grains consist of alternate surface terminations that do not display similar crystallographic properties as the (104) cleavage plane. This study focuses on the effect of miscut and step orientation on the long-term dissolution behavior of polished calcite surfaces in close to equilibrium fluid conditions with respect to calcite. The polished calcite surfaces were prepared by tilting the (104) cleavage plane at a varying miscut angle to produce forced obtuse step vicinal, forced acute step vicinal, and fully stepped miscut surfaces. Inductively coupled plasma (ICP) and profilometry results revealed that miscut angle has negligible influence on the average transient, long-term and mean dissolution rates. Furthermore, the ICP and microscopic results from atomic force microscopy (AFM) revealed that in the long-term, crystallographic step orientation is not a dominating influence since all vicinal surfaces as well as the fully stepped surface adopt similar surface morphology and hence exhibit comparable steady dissolution rates. Therefore we conclude that in CO2 sequestration environments, differently terminated calcite surfaces will have similar kinetic behavior in the long-term regardless of their crystallographic properties or step orientation.

Committee:

Steven Higgins, Ph.D. (Advisor); David Dolson, Ph.D. (Committee Member); Ioana Pavel, Ph.D. (Advisor)

Subjects:

Analytical Chemistry; Chemistry; Geochemistry

Zhang, GengxinGeomicrobial Processes and Diversity in Ultra-High Pressure Metamorphic Rocks and Deep Fluids from Chinese Continental Scientific Deep Drilling
Doctor of Philosophy, Miami University, 2006, Geology & Environmental Earth Science
This dissertation investigates the microbial communities and microbe-mineral interactions in ultra-high pressure metamorphic rocks and deep fluids from the Chinese Continental Scientific Drilling (CCSD) project by using geochemical, mineralogical, cultivation and molecular microbiology methods. The drilling site is located in the eastern part of the Dabie-Sulu ultra high-pressure metamorphic (UHPM) orogenic belt at the convergent plate boundary between the Sino-Korean and Yangtze Plates. This integrated approach conclusively demonstrates that microbes can survive in the deep continental subsurface (down to 3350 m) and they play important roles in mineral transformations and elemental cycling. The first half of this study focuses on geochemical conditions and diversity and metabolic functions of microbial community. Characterization of SSU rRNA genes indicated that the bacterial clone sequences shifted form a Proteobacteria-dominated community to a Firmicutes-dominated one with increased depth. From the ground surface to 2030 m, most clone sequences were related to nitrate reducers, with a saline, alkaline, and cold habitat. From 2290 to 3350 m most sequences were closely related to anaerobic, thermophilic, halophilic or alkaliphilic bacteria. The archaeal diversity was low. Most archaeal sequences from the ground surface to 3350m were not related to known cultivated species, but to environmental clone sequences recovered from subsurface marine environments. An important contribution of this research is an enrichment of a thermophilic (optimal temperature of 68°C) organism from 2450m with an ability to reduce Fe(III) and oxidize Fe(II) under different conditions. This enriched organism was capable of reducing Fe(III) in aqueous form and in the structure of clay minerals and iron oxides at acidic pH. This organism was also capable of oxidizing Fe(II) in aqueous form and in the structure of pyrite and siderite. The second half of this dissertation focuses on microbe-mineral interactions by using enriched and isolated cultures to react with clay and iron oxide minerals. Mesophilic and thermophilic iron-reducing bacteria were incubated with lactate as the electron donor and structural Fe(III) in solid minerals as the sole electron acceptor. Extensive mineral reaction took place. One important such reaction was the smectite to illite reaction promoted by mesophilic and thermophilic metal reducing bacteria. This particular reaction highlights the significant role of iron-reducing bacteria in promoting the smectite to illite reaction at high temperature.

Committee:

Hailiang Dong (Advisor)

Subjects:

Geochemistry; Geology

Keywords:

Fe; Drilling Fluids; Nontronite; illite; smectite; microbial

Tortorello, Rebecca DianeApplication of Uranium Isotopes as a Temporal and Spatial Tracer of Nuclear Contamination in the Environment
Master of Science, Miami University, 2012, Geology & Environmental Earth Science
The Fernald Feed Materials Production Center (FFMPC) was established in 1951 to process natural uranium ore and recycled recoverable products. This study tests the utility of sediment cores as a proxy for the degree and timing of anthropogenic uranium contamination, using the FFMPC as a test case. An 80 cm long sediment core was extracted from an impoundment located approximately 6.7km southwest of the FFMPC. The lack of measurable 137Cs in the deepest sample as well as a natural 235U/238U signature and no measurable 236U, are consistent with pre-FFMPC activity. The timing of elevated U concentrations, non-natural 235U/238U (0.00645 to 0.00748), and elevated 236U (236U/238U = 2.1x10-6 to 3.6x10-5) found in the sediment core coincide with the the two largest known U dust releases from the FFMPC. Three local lichen samples were also analyzed, and displayed either EU or DU signatures coupled with elevated 236U, recording airborne U contamination.

Committee:

Elisabeth Widom, PhD (Advisor); William Renwick, PhD (Committee Member); John Rakovan, PhD (Committee Member)

Subjects:

Environmental Geology; Environmental Science; Geochemistry; Geology; Nuclear Chemistry

Keywords:

Uranium; Isotope; Sediment core; Lichen; Fernald; Environmental contamination

Allen, Gerald R.An Analysis of the Fate and Transport of Nutrients in the Upper and Lower Scioto Watersheds of Ohio
Doctor of Philosophy, The Ohio State University, 2011, Geological Sciences

Surface water quality data are available from many public and private agencies across the United States. But, how can they be effectively utilized to help resolve the complex biogeochemical relationships of surface waters? The present study examined available stream and reservoir water quality, stream discharge, and meteorological time-series datasets for the Upper and Lower Scioto watersheds in central Ohio. The focus was on the fate and transport of nutrients, specifically nitrate and total phosphorus, in the streams and surface water reservoirs of these predominantly agricultural watersheds. The study area is composed of seven sub-watersheds, five of which contain major surface water reservoirs. Mean nitrate values for the more “riverine” J. Griggs and O’Shaughnessy reservoirs were more than double those for the more “lacustrine” Hoover and Alum Creek Lake reservoirs, and were at least partially due to the different reservoir morphometries and resultant residence times. Nitrate concentrations have gradually decreased over the periods of record in all four reservoirs. Phytoplankton populations in Hoover and Alum Creek Lake reservoirs are ecologically driven, while populations in O’Shaughnessy and J. Griggs reservoirs are weather and stream flow dependent.

The Big Darby Creek contains no major reservoirs or stream impoundments. From 1973 to 2008, annual-mean discharge ranged from 6.8 m3s-1 to 26.8 m3s-1 with an average of 16.1 m3s-1. Fall months were periods of lowest discharge, with spring to mid-summer months typically having highest discharge values. Nitrate and total phosphorus concentrations exhibited a wide range with means closely similar to the values in O’Shaughnessy and J. Griggs reservoirs. Nitrate concentrations have slowly increased in the Big Darby Creek study area from 1973 to 2010. Quadratic model regression analysis showed nitrate concentration had a strong positive relationship with corresponding daily-mean discharge, but total phosphorus concentration was uncorrelated. Seasonal nitrate and daily-mean discharge trends were positive and similar except for fall, which could have been biased by a lack of concentration data for low flows. An analysis of stream flow dynamics suggests that chloride is primarily associated with ground water and is negatively related to stream discharge. Nitrate concentration is predominantly associated with precipitation generated surface runoff or tile-drained discharges from crop lands. The nitrate reservoir in the soil horizon of the Big Darby Creek watershed is gradually depleted from winter to fall.

A conceptual model for the prediction of nitrate concentration at the USGS gaging station at Chillicothe, terminus of all study area surface water, is the sum of the calculated nitrate concentrations of all seven sub-watersheds. Main components of the model are the calculation of daily discharge and nitrate concentrations for the individual sub-watersheds. The model is specifically designed to capture the effect widespread precipitation events have on individual sub-watershed areas, and can be modified for the prediction of other watershed nutrient concentrations. This study has provided an important first step in the quantitative interpretation of the origin of complexity in the development of understanding of nutrient distribution in large watersheds.

Committee:

Franklin Schwartz, PhD (Committee Chair); Carolyn Merry, PhD (Committee Member); Motomu Ibaraki, PhD (Committee Member); Costa Ozeas, PhD (Committee Member)

Subjects:

Geochemistry; Geology; Hydrologic Sciences; Hydrology; Water Resource Management

Keywords:

Upper and Lower Scioto; fate and transport; nutrients; phytoplankton; reservoirs; conceptual model

DeWitt, Debra J.Assessment of the Water Quality of Stream Discharge into Furnace Run Metro Park, Richfield Township, Summit County, Ohio
Master of Science, University of Akron, 2012, Geology-Environmental Geology
With the growing population, development of large residential houses, commercial and industrial developments, and the construction of Interstate 80 and Interstate 77 interchange, water quality of Furnace Run has become an important issue. Recent studies by the Ohio EPA have found the stream to only be in partial attainment for aquatic life. In 2003 a study by the Metroparks found high dissolved solids in one of the tributaries to Furnace Run that flows through the park. The high dissolved solids were attributed to the ongoing construction of the highway interchange. The purpose of this study was to determine the influence western and eastern tributaries that flow within Furnace Run Metropark have on the water quality of Furnace Run. The land use west of Furnace Run consists of large housing developments; and that to the east consists of highways, an interchange, houses, commercial, and industrial developments. Field work was performed on 23 tributaries, and Furnace Run itself, within the Furnace Run Metropark from June 5, 2010, through April 9, 2011. Water samples were collected nine times during the study period from Furnace Run and its tributaries for water quality analysis for common anion concentrations; and on two occasions, samples were collect for analysis for cation concentrations. The cation and anion data were used to create Piper diagrams to determine water types. Also, suspended sediment load was measured using the Ohio Sediment Stick to find the actual amount of mineral and organic particles transported in the tributaries. This study found that the use of road deicer in the winter months may be contributing to the high concentration of chloride in Furnace Run and its tributaries. The eastern tributaries were affected the most due to their location near the highways. Duration between storm events also had an effect on the water quality of the streams. Pollutants were able to build up on roadways and other surfaces during dry days, which may have lead to the increase in pollutant concentrations in the streams during the first flush from the next storm event.

Committee:

John Szabo, Dr. (Advisor); LaVerne Friberg, Dr. (Committee Member); John Peck, Dr. (Committee Member)

Subjects:

Geochemistry

Keywords:

Furnace Run; water quality; suspended sediment; NE Ohio; Cuyahoga River Watershed

Yu, HuiminLi, Hf and Os Isotope Systematics of Azores Basalts and A New Microwave Digestion Method for Os Isotopic Analysis
Doctor of Philosophy, Miami University, 2011, Geology & Environmental Earth Science

This dissertation includes three projects related to the isotope geochemistry of ocean island basalts (OIB) in the Azores archipelago. Detailed studies of Hf, Os and Li isotope systematics are combined with Sr-Nd-Pb isotopes and trace elements to investigate the nature and origin of mantle heterogeneity beneath the Azores. In addition, new microwave digestion methods have been developed and tested for dissolution of samples for Os isotope analysis.

The first project focuses on Hf-Os isotope systematics of basalts from the Azores Central Group islands (Faial, Pico, São Jorge and Terceira) with HIMU and EM-type signatures. Sub-chondritic 187Os/188Os and ΔεHf signatures on or slightly below the terrestrial εHf - εNd array indicate that the mantle sources of these basalts do not contain significant recycled crustal material. Rather, the sources of the basalts are interpreted to include variable and geographically controlled mixtures of a deeply derived enriched mantle plume, relatively depleted mantle similar to that beneath the Mid-Atlantic ridge, and recycled metasomatized mantle wedge.

The second project focuses on assessing the utility of Li isotopes as a tracer of heterogeneous mantle sources. The δ7Li data of Central Group island (Faial, Pico and Terceira) and São Miguel basalts vary only slightly (+3.1 to +4.7‰), and are all within the range of normal MORB, despite large variations in radiogenic isotopes. Nevertheless, the Central Group island basalts have, on average, slightly higher δ7Li than São Miguel, and exhibit positive correlations with Sr and Os isotopes, and negative correlations with Pb, Nd and Hf isotopes, and are consistent with the interpretations of the Hf-Os isotope study. New diffusion modeling furthermore suggests that mantle heterogeneities induced by subduction processes may be maintained in the mantle for timescales of >2.5Ga.

The third project assesses the utility of microwave digestion for Os isotopic analysis. Compared to conventional Carius tube digestions, microwave digestion is faster and safer, and allows for the use of HF to achieve complete dissolution of silicate samples. This study demonstrated that microwave digestions successfully achieve spike-sample equilibration, have acceptably low processing blanks, and produce yields >90%.

Committee:

Elisabeth Widom, Ph.D. (Advisor); William Hart, Ph.D. (Committee Member); Michael Brudzinski, Ph.D. (Committee Member); Paul Tomascak, Ph.D. (Committee Member); Michael Crowder, Ph.D. (Committee Member)

Subjects:

Geochemistry; Geology

Keywords:

Ocean island basalts; Azores; Faial; Pico; S&227;o Jorge; S&227;o Miguel; Terceira; geochemistry; radiogenic isotopes; lithium isotopes; trace elements; mantle plume; mantle heterogeneity, microwave digestion; osmium separation; distillation

Groshong, Kimberly AnnModeling the Effect of Calcium Concentration and Volumetric Flow Rate Changes on the Growth of Rimstone Dam Formations Due to Calcium Carbonate Precipitation
Master of Science, University of Akron, 2008, Applied Mathematics
Rimstone dams, formed in cave environments and composed primarily of calcium carbonate, are constructed through both chemical and mechanical processes. As calcium rich water flows over a sloped limestone cave floor, calcium carbonate precipitates from the solution. Standard fluid mechanics equations govern the hydrodynamics. Chemical kinetics describe movement through the boundaries and explain the bulk and surface reactions that influence precipitation. The free boundaries, gas-fluid and solid-fluid interfaces, couple the hydrodynamic and reactive transport equations. The chemical kinetics of bulk and surface reactions that result in precipitation are determined. This research focuses on the effect of changing the volumetric flow rate and altering the concentrations of calcium on the growth of the mineral-fluid boundary by developing and solving, through thin-film fluid flow approximations, appropriate hydrodynamic and reactive transport equations. Three general volumetric flow conditions are explored in this paper. The effect of slow, moderate, and fast flow rates under conditions of constant flow; exponentially decreasing flow, modeling drought conditions; and seasonal flow fluctuations about a base rate are investigated. The greatest growth was observed during seasonal fluctuations with a moderate volumetric flow rate. Greatest deposition, near the initial position, was with high concentrations of calcium flowing with a fast flow rate. Further downstream, the largest growth required small concentrations of calcium, which maintained a high pH condition in the system. From the developed equation for the mineral boundary, growth was affected by pH conditions driven from bulk reactions and influenced by degassing of carbon dioxide and surface reactions from the alterations in calcium concentration, ultimately driving the system pH.

Committee:

Gerald Young (Advisor); Curtis Clemons (Advisor)

Subjects:

Geochemistry; Geology; Geophysics; Mathematics

Keywords:

Rimstone Dams; calcium precipitation; cave formations;asymptotic expansion;volumetric flow rate;coupled differential equations

Pepple, Chris CFactors Affecting the Precipitation of Quartz Under Hydrothermal Conditions
Master of Science (MS), Bowling Green State University, 2008, Geology
Natural Pocono Sandstone and synthetic quartz crystals, crushed and sieved (125-250um), have been used to experimentally evaluate changes in the rate and nature of quartz cementation under hydrothermal conditions. Experiments were carried out from 1 hour to 5 weeks at temperatures of 300-600°C and at 150 MPa confining pressure to simulate cementation conditions analogous to a quartz reservoir at depth. Experimental charges consisted of AlCl3, amorphous silica, NaCl brine, and one of the quartz sample materials weld-sealed in a gold tube. Interactions of quartz systems with and without the addition of iron oxides (goethite) were conducted to determine the influence of iron oxides on cementation. After the experiments, samples were impregnated with epoxy and then analyzed using cathodoluminescence (CL), plain polarized light (PPL), cross polarized light (XPL), and scanning electron microscopy (SEM). Mosaic images were constructed for node counting of grains, cement, and porosity for synthetic quartz samples, and grains and porosity measures for Pocono Sandstone experiments. The mosaic images illustrate precipitation and dissolution occurred at sample bases and tops due to a saturation gradient formed by the interactions of AlCl3 and amorphous silica. Measured cement and porosity values of synthetic quartz samples were used to calculate precipitation and transport rates detailing differences between pure and goethite system experiments. Consistently, synthetic quartz goethite experiments showed greater cementation in response to increased silica solubility and goethite’s pervasive and adsorptive nature towards quartz. In addition, it is shown that significant amounts of quartz cementation can occur due to saturation gradients between quartz and amorphous silica even in the absence of a temperature or pressure gradient.

Committee:

John Farver (Advisor)

Subjects:

Geochemistry; Geology

Keywords:

Pocono Sandstone; quartz; silica; cementation; precipitation; amorphous silica; goethite; cathodoluminescence

Moyer, Ryan P.Carbon Isotopes (δ13C & Δ14C) and Trace Elements (Ba, Mn, Y) in Small Mountainous Rivers and Coastal Coral Skeletons in Puerto Rico
Doctor of Philosophy, The Ohio State University, 2008, Geological Sciences
Tropical small mountainous rivers (SMRs) may transport up to 33% of the total carbon (C) delivered to the oceans. However, these fluxes are poorly quantified and historical records of land-ocean carbon delivery are rare. Corals have the potential to provide such records in the tropics because they are long-lived, draw on dissolved inorganic carbon (DIC) for calcification, and isotopic variations within their skeletons are useful proxies of palaeoceanographic variability. The ability to quantify riverine C inputs to the coastal ocean and understand how they have changed through time is critical to understanding global carbon budgets in the context of modern climate change. A seasonal dual isotope (13C & 14C) characterization of the three major C pools in two SMRs and their adjacent coastal waters within Puerto Rico was conducted in order to understand the isotope signature of DIC being delivered to the coastal oceans. Additionally a 56-year record of paired coral skeletal C isotopes (δ13C & Δ14C) and trace elements (Ba/Ca, Mn/Ca, Y/Ca) is presented from a coral growing ~1 km from the mouth of an SMR. Four major findings were observed: 1) Riverine DIC was more depleted in δ13C and Δ14C than seawater DIC, 2) the correlation of δ13C and Δ14C was the same in both coral skeleton and the DIC of the river and coastal waters, 3) Coral δ13C and Ba/Ca were annually coherent with river discharge, and 4) increases in coral Ba/Ca were synchronous with the timing of depletions of both δ13C and Δ14C in the coral skeleton and increases in river discharge. This study represents a first-order comprehensive C isotope analysis of major C pools being transported to the coastal ocean via tropical SMRs. The strong coherence between river discharge and coral δ13C and Ba/Ca, and the concurrent timing of increases in Ba/Ca with decreases in δ13C and Δ14C suggest that river discharge is simultaneously recorded by multiple geochemical records. Based on these findings, the development of coral-based proxies for the history of land-ocean carbon flux would be invaluable to understanding the role of tropical land-ocean carbon fluxes in the context of global climate change.

Committee:

Andrea Grottoli, PhD (Advisor); James Bauer, PhD (Committee Member); Anne Carey, PhD (Committee Member); Yu-Ping Chin, PhD (Committee Member); Matthew Saltzman, PhD (Committee Member)

Subjects:

Biogeochemistry; Geochemistry; Geology; Oceanography

Keywords:

Coral Biogeochemistry; Carbon Isotopes; Carbon Cycle; Land-Ocean Carbon Flux; Puerto Rico; Trace Elements; ICPMS

Khadka, Mitra B.Variation in Trace Metal Concentrations in A Fluvial Environment, Ottawa River, Toledo, Ohio
Master of Science (MS), Bowling Green State University, 2010, Geology
Surface sediment samples were collected from a 1000 m meander reach of the Ottawa River, Ohio and analyzed for trace metals (Zn, Pb, Sr, Mn, Cu, Cr, Co, Ba, Ti, Cd, and Hg) by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) to determine the local variability in their concentrations between geomorphic features. Eight metals (Zn, Pb, Sr, Mn, Cu, Cr, Co, and Ba) show significantly different concentrations between five fluvial geomorphic features namely, flood plains, point bars, lateral bars, pools, and riffles. Among the features, flood plains and lateral bars are places where flows are decelerated due to surface roughness and vegetation cover, promoting the deposition of fine-grained sediments and organic matter. Thus, flood plains and lateral bars consistently exhibit the highest metal concentrations. The lowest metal concentrations in point bars are attributed to relatively coarse-grained sediment and low organic matter content. The difference in mean metal concentration between flood plains and point bars ranges from 5 times for Co to 12.5 times for Pb. It was found that Zn, Sr, Mn, Cu, Cr, Co, and Ba are influenced by similar transport and interaction processes, and possibly have common sources, while Pb shows a weak to non-significant association with other metals indicating either a different mode of transport or separate anthropogenic sources. The concentrations of all metals in 89% of the samples are below the Threshold Effect Level (TEL) and the Probable Effect Level (PEL), and thus sediment contamination issues are to be minor concern in this section of the river. The finding that flood plains serve as sediment-associated metals sink can have important implications for monitoring and regulation, impact assessment, and remediation of contaminated sediments in metal contaminated section of the Ottawa River or for other rivers having similar geomorphological, hydrological, and sedmentological characters.

Committee:

Sheila J. Roberts (Advisor); James E Evans (Committee Member); Enrique Gomezdelcampo (Committee Member)

Subjects:

Earth; Environmental Science; Geochemistry; Geology; Hydrology

Keywords:

trace metal; fluvial geomorphology; sediment contamination; environment; ottawa river; flood plain

Shaw, Meaghan ElizabethConcentration-discharge behavior of contaminants in a stream impacted by acid mine drainage
MS, Kent State University, 2018, College of Arts and Sciences / Department of Geology
Acid mine drainage (AMD) is a common byproduct of mining that has severely degraded many streams world-wide. In coal mining, AMD occurs when pyrite contained in coal is exposed to water and air during mining activities and oxidized to release high concentrations of sulfate, metals, and acid into water bodies. Controls on concentration-discharge (CQ) relationships of solutes in AMD-impacted streams remain unclear due to the complicated nature of acid mine drainage systems. For example, streams may receive inputs from multiple sources including runoff, outflow from constructed treatment systems, and abandoned mines that bypass these systems to continue to contaminate the streams. It is important to understand the CQ relationships of contaminants in AMD-impacted streams in order to elucidate contaminant sources and to predict effects on aquatic ecosystems under different flow regimes. Here, we study the CQ behaviors of acid, metals, and sulfate in an AMD-contaminated watershed in northeastern Ohio where a treatment system has been installed to remediate water draining from a mine pool into the stream. The treatment system includes a series of limestone channels and settling ponds designed to increase drainage pH and promote precipitation of Fe- and Mn-oxides. Stream chemistry was measured in samples collected approximately once per day from March through November and hourly during select storm events. Stream flow was measured continuously at the watershed outlet. Contaminant concentrations in the stream generally decreased with increasing stream discharge due to inputs from the treatment system that only occurred at high flow. A decrease in pH from March (~6) through November (~3) was concurrent with a decrease in stream discharge and declining inputs from the treatment system. Correspondingly, AMD-derived contaminants (Fe, Mn, Al) increased in concentration from March through November. These trends reflect mixing of contaminated baseflow and intermittent inputs from the treatment system, indicating that the treatment system is only effective at neutralizing stream acidity and removing metals when flow is present. We determine that constructed treatment systems can act as ephemeral tributaries to the stream and control CQ behavior at the stream outlet.

Committee:

Elizabeth Herndon (Advisor); David Singer (Committee Member); Anne Jefferson (Committee Member)

Subjects:

Geochemistry; Geology

Keywords:

Concentration-discharge; acid mine drainage; water chemistry

Michael, TaylorInvertebrate Activities in Wetland Sediments Influence Oxygen and Nutrient Dynamics at the Sediment-water Interface
BS, Kent State University, 2018, College of Arts and Sciences / Department of Biological Sciences
Invertebrate activities at the sediment-water interface can facilitate nutrient retention, release, and transformation by changing the nature of oxygen penetration into anoxic sediments, influencing geochemical and microbial-mediated processes. By reworking sediment and conveying oxygenated surface water into deeper anoxic sediment through burrowing activities, bioturbating invertebrates influence nutrient cycling in wetlands sediments. To test the effects of bioturbators on oxygen introduction and nutrient fluxes, we investigated the impacts of two functionally different bioturbators at a range of four densities using a microcosm study. We measured sediment oxygen penetration depth at small-scale resolution using microelectrode sensors and analyzed surface water nutrients weekly over four weeks. Results indicate increased oxygen penetration in regions of normally anoxic sediment with the presence of each of the two bioturbation modes. In general, we observed negative phosphorus fluxes (i.e., into the sediment) with increasing bioturbator densities, indicating retention in the sediment due to bioturbation activities. These activities caused enough retention of phosphorus to counteract the phosphorus released by bioturbator excretion alone. There was a flux of nitrate into the surface water, likely driven by invertebrate excretion of ammonia followed by an oxidative process such as nitrification. This investigation contributes to the growing understanding of how organisms influence nutrient cycling in wetlands, which are hotspots for biogeochemical processing.

Committee:

Lauren Kinsman-Costello (Advisor); Andrea Fitzgibbon (Other); David Costello (Committee Member)

Subjects:

Biogeochemistry; Ecology; Freshwater Ecology; Geochemistry

Keywords:

Bioturbation; bioturbation modes; invertebrates; freshwater ecosystems; wetlands; biogeochemistry; nutrient exchange

Goldschmid, Tanhum, 1941-Aqueous chemistry and precipitation of aluminum phosphate /
Doctor of Philosophy, The Ohio State University, 1975, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geochemistry

Keywords:

Phosphates;Water

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