Master of Science (MS), Wright State University, 2012, Earth and Environmental Sciences

Photosynthesis, respiration, and decay of organic matter all involve the transfer of carbon among the carbon-bearing species in the systems. These biogeochemical processes also fractionate the carbon isotope composition, which results in changes to the carbon isotope composition of the dissolved inorganic carbon (DIC) pool. This thesis presents two separate, but related studies regarding the influence of biogeochemical processes on carbon isotopes in local lakes. Crystal Lake is a small but deep glacial lake (12.5 acres, 11.9 meters). The study shows that during thermal stratification, the heaviest carbon can be found in the epilimnion near the surface, where photosynthesis dominates the biogeochemical processes. At greater depths, the DIC carbon becomes lighter as 12C-enriched organic matter decomposes. In the hypolimnion, methane production in the late summer could be the process that resulted in slight increase in 13C of DIC. The second study investigated the relationship between the carbon isotope composition of DIC and the trophic status of three lakes in Southwestern Ohio; Indian Lake, Grand Lake St. Marys and Kiser Lake. All three lakes are shallow, man-made reservoirs, but each has unique biogeochemical characteristics. Among these three lakes, Grand Lake St. Marys had the heaviest carbon isotope composition in DIC, the highest phosphorus (P) concentration, and the lowest nitrate (N) concentration. It is the only lake among the three that has suffered severe toxin-producing blue-green algae (cyanobacteria) blooms in recent years. The P and N concentrations indicated nitrate was the limiting nutrient. This study shows that carbon isotope composition can be used as a proxy for trophic status in large, shallow lakes, like Indian Lake and Grand Lake St. Marys. It is concluded that carbon isotope composition of DIC is closely related to the biogeochemical processes in lakes and can provide important insight into those processes. However, a quantific (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 1974, Graduate School

MA, University of Cincinnati, 2015, Arts and Sciences: Geography

The formation of oriented thermokarst lakes on the Arctic Coastal Plain of northern Alaska has been the subject of debate for more than half a century. The striking elongation of the lakes perpendicular to the prevailing wind direction has led to the development of a preferred wind-generated gyre hypothesis, while other hypotheses include a combination of sun angle, topographic aspect, and/or antecedent conditions. A spatio-temporal analysis of oriented thermokarst lake gyres with recent (Landsat 8) and historical (Landsat 4, 5, 7 and ASTER) satellite imagery of the Arctic Coastal Plain of northern Alaska indicates that wind-generated gyres are both frequent and regionally extensive. Gyres are most common in lakes located near the Arctic coast after several days of sustained winds from a single direction, typically the northeast, and decrease in number landward with decreasing wind energy. This analysis indicates that the conditions necessary for the Carson and Hussey (1962) wind-generated gyre for oriented thermokarst lake formation are common temporally and regionally and correspond spatially with the geographic distribution of oriented lakes on the Arctic Coastal Plain. Given an increase in the ice-free season for lakes as well as strengthening of the wind regime, the frequency and distribution of lake gyres may increase. This increase has implications for changes in northern high latitude aquatic ecosystems, particularly if wind-generated gyres promote permafrost degradation and thermokarst lake expansion.

Doctor of Philosophy, The Ohio State University, 2009, Civil Engineering

Present day numerical models of water bodies are being called upon to make increasinglyfrequent predictions with elevated accuracy standards and requirements. Such a hydrodynamic prediction system is applied in Lake Erie and its ability to accurately model the Lake water elevations is examined in great detail during the 1999-2000 period to decide whether it complies with the currently acceptable standards set for water elevation forecasting and datum establishment purposes. The core model of the prediction system is the Princeton Coastal Ocean Model (POM) that is applied in both its 3D and 2D versions to test whether: a) the 3D calculations predict better the near shore surge amplitudes and b) the 2D calculations provide the accuracy level required by datum determination studies. The model is evaluated at the near-shore lake regions using observed data acquired from 14 land stationed water elevation gages and at the off-shore lake regions using observed data acquired from the Topex/Poseidon water level observation system. Because calculations of water elevations from altimetry data are still impeded by the need for a reliable geoid model, water elevations generated by the POM are pre-processed to provide water surface anomalies to be compared against water surface anomalies provided by the altimetric water level observation system. Upon the complete evaluation of the prediction system initial set up, the following questions are also addressed: a) what is the best method for accounting for the hydrological variations in the lake water levels; b) how does the meteorological data frequency of observation, the consistency of all the meteorological data parameters, and the meteorological station density and distribution over the lake affect the system predictive ability; and c) what is the best interpolation method for gridding the observed meteorological data. The results showed an improvement of the overall model's predictive ability and a better performance especially (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2009, Geological Sciences

Hydrologically closed basins in arid environments often pose ideal conditions for the development of inland saltwater lakes. In these regions, where the hydrology is balanced by dilute inflow waters and evaporation, these closed-basin lakes may progress through various degrees of evapoconcentration. This process may result in the precipitation of simple salts and the alteration of the relative chemical composition of a lake. Such “geochemical evolution” processes have been studied in detail particularly for the so-called major ions (Na, Ca, K, Mg, Cl, SO4, HCO3+CO3) and Si, but little work has been done on ions of moderate concentration. Due to the evaporative nature of these systems, the alkali metals, Li and Rb, and alkaline earth elements, Sr and Ba, may become highly concentrated and play a significant role in determining the geochemistry of a saline lake. Here, I present the first comprehensive study of the transport and fate of the minor alkali elements, Li, Rb, Sr, and Ba, in three distinct geographic settings illustrating three types of saline lakes as determined by their major anion abundance. Using lithium isotope analysis and mass balance calculations, I show that the minor elements in the McMurdo Dry Valleys are transported to “chloride-type” lakes by a combination of precipitation, chemical weathering and salt dissolution. Sr and Ba show evidence of removal in the lakes, but Li and Rb appear to be conservative to extremely high concentrations. This work discusses the potential removal mechanisms of these ions, particularly the formation of major and minor sulfate and carbonate minerals in the lakes. A major finding of this study is that brine type determines the removal mechanism of Sr and Ba, particularly if they are removed as sulfate or carbonate minerals. This study provides a platform for future exploration of the role of these and other minor elements in inland brines and playas.

Master of Science, The Ohio State University, 1986, Graduate School

Master of Science, The Ohio State University, 1979, Graduate School

Master of Science, The Ohio State University, 1978, Graduate School

MS, Kent State University, 2025, College of Arts and Sciences / Department of Biological Sciences

Eutrophication in lakes is often the result of human activity and land-use changes, particularly the loss of or modification to wetlands, at a watershed-scale. Many state and federal governments are turning to wetland protection, restoration, and construction to meet water quality goals. Better characterization of biogeochemical characteristics related to P-sorption across spatial and temporal scales is needed to inform wetland management decisions and design, set realistic expectations for P storage, and anticipate potential P export events. Here we investigated whether the integrated biogeochemical effects of hydrology and the associated wetland plant community assemblages lead to macro-scale differences in several parameters related to Fe-driven P retention in wetland sediments during the growing season in an intact, freshwater, lacustrine wetland on the coast of Lake Erie (Old Woman Creek Estuary, Huron OH). Additionally, we assessed the magnitude of iron's role in sediment P dynamics, among distinct hydro-eco patches. As hypothesized, we did find significant differences in some parameters related to sediment P biogeochemistry and the Fe to P relationship between hydro-eco patches. Typha-dominated patches showed distinct biogeochemical characteristics, including higher concentrations of porewater Fe, soil P, and P sorption capacity.

Master of Science, The Ohio State University, 1969, Graduate School

Master of Science, The Ohio State University, 1970, Graduate School

Doctor of Philosophy, The Ohio State University, 2024, Food, Agricultural and Biological Engineering

As catchments become increasingly impervious, urban stormwater pollutant loads, erosional force, and flooding increases. The practice of stormwater management is critical environmental protection that became regulated by the US federal government in the 1970s. With the need to attenuate peak flow rates and reduce the excess stormwater volumes generated from impervious catchments, stormwater control measures (SCMs) were developed such as stormwater detention basins, retention ponds, drainage ditches, and subsurface stormwater detention. Having a variety of SCMs available provides stakeholders with the ability to target specific aspects of stormwater management, including runoff quantity, runoff quality, or other ecosystem services. Regulations have evolved over time to have a greater emphasis on stormwater quality. As such, SCM design has evolved to address pollutant removal in stormwater. Green infrastructure (GI) practices, also called low impact development (LID) SCMs, have gained popularity for stormwater management since the start of the 21st century and incorporate principles of ecological engineering into stormwater management. Examples of GI include a variety of practices that use infiltration through filter media such as rain gardens, bioretention cells (BRCs), and high rate biofiltration (HRBF), permeable pavements, green roofs, and constructed stormwater wetlands (CSWs). The use of GI has benefits in addition to peak flow, volume, and pollutant reduction such as creating habitat for pollinators, cooling urban spaces, and adding attractive green space. Pollutant removal mechanisms vary between GI practices with some systems providing greater sedimentation and treatment of particulates and some providing greater treatment of dissolved pollutants through microbially-mediated transformation, plant uptake, and/or adsorption. Performance of SCMs varies based on design, site characteristics (e.g. topography, soil texture and infiltration capacity, depth to wa (open full item for complete abstract)

MS, University of Cincinnati, 2024, Arts and Sciences: Geology

The hydrogen isotopic composition (δ2H) of lipid biomarkers extracted from lake sediment serves as a valuable tool for tracking changes in the hydrologic cycle by reflecting changes in the δ2H of their source water. However, interpreting these changes is complicated by the mixture of terrestrial and aquatic lipids preserved in lake sediments, which present δ2H values influenced by different source waters (i.e. precipitation and lake water). Highly branched isoprenoids (HBI) produced by diatoms are suggested as a proxy for lake water hydrogen isotopic composition (δ2Hlw) that avoid terrestrial interferences. The controls on hydrogen isotope fractionation between HBI and its lake water source (ε2HHBI/lw) must be better constrained to improve the utility of HBI as a proxy for δ2Hlw. Here we measure ε2HHBI/lw across a broad study area comprising 48 lakes spanning 10 US states. We analyzed sediment, water filter, and sediment trap samples to evaluate the consistency of ε2HHBI/lw across the study area and identify factors controlling its variability. We observed a consistent and significant disparity in ε2HHBI/lw between sediment and water filter samples, suggesting that sedimentary ε2HHBI/lw values are not solely dictated by the hydrogen isotopic composition of HBI (δ2HHBI) in the water column during the sampling season (May-June). Furthermore, consistent with prior smaller-scale studies, we observed a standard deviation of ±30‰ in ε2HHBI/lw across the study area, comparable to that of widely accepted precipitation proxies such as plant waxes. These results demonstrate that δ2HHBI can be used to track changes in δ2Hlw through time. They also show that the effectiveness of δ2HHBI as a tool for reconstructing paleohydrology can be improved by developing a set of criteria to enable carful site selection that targets lakes with more consistent ε2HHBI/lw values, which are best suited for such studies.

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2024, English (Rhetoric and Writing) PhD

In 2019, The Lake Erie Bill of Rights (LEBOR) was voted onto the city charter of Toledo, Ohio. The charter amendment made it possible for citizens of the city of Toledo to sue polluters on behalf of the Lake, effectively giving Lake Erie more standing in court closer to that of legal personhood. A year later, LEBOR was deemed unenforceable by Judge Jack Zouhary, who critiqued it as vague and reaching too far beyond the jurisdiction of Toledo. This dissertation starts from those two critiques, analyzing how LEBOR fell short in 1. specifically connecting to the thousands of years of landscape practices and relations Indigenous residents had developed in the time before the region was colonized and 2. understanding the Lake as a place with a dynamic set of naturecultural relations with deep ties to the watershed and landscape within the jurisdiction of Toledo. This analysis uses theories from spatial rhetoric, placemaking, naturecultural critique, Indigenous scholarship, and postcolonial studies focused on the U.S. to understand why these shortcomings occurred and how future activist composers can possibly benefit from avoiding them. At the center of the analysis is an oral history composed using only the words of the activists in order to ground the work in their more immediate context. The dissertation concludes by evaluating how my analysis of LEBOR can be applied to teaching writing in and outside of the classroom and to scientific research projects that may otherwise be falling short in their connection with the public connected to the knowledge they gather and the organisms and entities they research.

Master of Science, The Ohio State University, 2024, Environment and Natural Resources

Millions of migratory birds are funneled through the Great Lakes Region annually and depend on the shoreline habitats for stopover and refueling. The Great Lakes Region also has a high capacity for offshore wind development. Environmental assessments of a proposed experimental six-turbine array located eight miles offshore from Cleveland, Ohio determined that the impact to migratory birds would be low citing that birds avoid crossing the lake, which contrasts previous individual bird tracking studies showing an estimated 70% of birds crossed Lake Erie after stopping over on the lakeshore. The high crossing rate of some species suggests the potential for increased risk of avian collisions with offshore structures if improperly placed. Collisions with anthropogenic structures such as buildings account for upwards of 988 million annual deaths in the United States. Comparatively, turbines account for lower levels of mortality in the U.S. (679 thousand birds), but these estimates likely underrepresent the total impact due to surveying difficulties and data restrictions for industry reports. Additionally, this number is likely to increase with expansion of wind energy in the United States making now a critical time to close knowledge gaps related to offshore wind impact and to ensure proper siting of turbines that minimizes the risk to migratory birds. Understanding lake-crossing behavior and shoreline usage of birds in the region is necessary for predicting risk. Using Lake Erie as the focus for this study, I sought to determine the prevalence of lake-crossing behavior for migratory songbirds by tracking the movement of individuals from inland stopover habitats and identifying high use areas along the shoreline. Using automated radio telemetry and the Motus Wildlife Tracking System, I deployed transmitters on 174 birds from a suite of study species including White-throated Sparrow (Zonotrichia albicollis), Swainson's thrush (Catharus ustulatus), Tennessee Warble (open full item for complete abstract)

PHD, Kent State University, 2024, College of Arts and Sciences / Department of Biological Sciences

Freshwater aquatic ecosystems, including lakes and wetlands, provide habitat for abundant and diverse animal communities, which can have large impacts on nutrient (nitrogen [N] and phosphorus [P]) biogeochemistry. Animals play an important role in nutrient recycling in freshwater ecosystems but are infrequently considered in nutrient management. It is broadly known that animals provide nutrients via excretion and egestion, however, less is known about how animals indirectly influence nutrient retention and release through interacting with aquatic sediments, and how their nutrient contributions shape aquatic communities and ecosystem functions such as primary production. Waterbirds (i.e., ducks, geese, wading birds, cormorants) and benthic invertebrates (i.e., benthic dwelling oligochaete worms, insect larvae such as mayfly and chironomid taxa) are common in Great Lakes aquatic ecosystems, yet their roles in shaping nutrient budgets and loading are often overlooked. The overall focus of this dissertation was to understand how sediment-surface water nutrient dynamics and ecosystem processes are shaped by aquatic animals and different water oxygen conditions in a variety of Great Lakes freshwater aquatic ecosystems. We demonstrate that multiple animal groups can measurably shape nutrient dynamics with implications on other ecosystem functions. In the first study, we investigated multiple internal load contributions, including net ambient and bioturbator-mediated sediment-surface water nutrient exchange, in Sandusky Bay, Lake Erie. We found that invertebrate bioturbation supplied P and N and made up a significant component of net internal fluxes, and internal sources made up a significant proportion of the total P load in this shallow, freshwater embayment. In the second study, we examined how the late-summer hypoxic event in Lake Erie shapes sediment oxygen and redox-sensitive indicators to better understand how hypoxia stressors affect sediment conditions and processe (open full item for complete abstract)

Doctor of Philosophy, Miami University, 2024, Biology

Midwestern North American lakes, including the Laurentian Great Lakes, are experiencing significant increases in water transparency due to invasive Dreissenid mussels and improved watershed management practices. Climate change loss of winter has reduced annual ice cover on the lakes. Increases in water transparency combined with the absence of ice cover in the winter may lead to an increased risk of exposure to damaging ultraviolet radiation (UV), which is known to regulate the early life stages of fish. Despite these potential increases in underwater UV, very little is known of the current day UV transparency throughout the Great Lakes, nor the UV tolerance or mechanisms of protection of the early life stages of a culturally, economically, and ecologically important subfamily of native Great Lakes fish: Coregonine (i.e., Lake Whitefish [Adikameg; Coregonus clupeaformis], Cisco [Otoonapi; C. artedi], and Bloater [C. hoyi]), nor an economically important invasive prey species of fish: Alewife (Alosa pseudoharengus). This dissertation investigated 1) the spatial and temporal UV transparency patterns across the Great Lakes, 2) the ability for UV to accelerate the hatching of native Cisco eggs, 3) the UV tolerance, mechanisms of protection, and sublethal consequences of exposure to UV among two life stages, four species and multiple populations of fish and 4) the influence of UV on the vertical distribution of larval Alewife and Bloater within Lake Michigan. Although long-term offshore UV data does not exist, long-term nearshore UV data suggest shallower UV exposure correlated with increasing dissolved organic carbon concentrations. Laboratory experiments revealed that developing Cisco embryos exposed to UV have the potential to hatch 30 days earlier than embryos unexposed to UV, the egg life stage of all native coregonines tested had a higher UV tolerance than the larval life stages, and the UV tolerance among species and populations of the same species varied. Field s (open full item for complete abstract)

MS, Kent State University, 2024, College of Arts and Sciences / Department of Geography

Snow and ice-covered roads cause numerous issues from slippery pavement to severely reduced visibility and thus can hinder transportation services and impact public safety. Car crashes are one such common occurrence during wintry conditions. While the overall relationship between traffic accidents and adverse weather conditions has been studied by many, little research has been done to quantify the association between repeated small-scale winter weather events and motor vehicle accidents. Findings that have been reported about these accident hotspots have focused more on snow overall than its source or just lake-effect snow exclusively and not in comparison to synoptic-scale systems. This study aims to address the gap in knowledge about how different types of localized winter weather affect the distribution of motor vehicle accidents over space and time, as well as to expand upon past synoptic climatological research on lake-effect snow. Analyses of crashes in Northeast Ohio by winter season weather type concur with past work on the hierarchy of crash risk by precipitation type being, in order from the highest chance of causing an accident to the lowest, experienced during freezing rain, snow, and then rain. Further results reveal how the inconsistent nature of lake-effect snow influences motor vehicle accident frequency with the largest spatiotemporal indicators of elevated relative risk during lake-effect snow occurring when crash counts are broken down by county/county region, road type, and month. In certain scenarios, lake-effect snow may be associated with up to a 20 times greater likelihood of an accident occurring than in clear conditions. These conclusions can provide important information for local and regional transportation officials to improve winter weather roadway management.

PHD, Kent State University, 2023, College of Arts and Sciences / Department of Biological Sciences

This dissertation is focused on the direct and indirect effects of micronutrients (Fe, Mo, Mn, Ni, Zn) in combination with macronutrients on algal community composition, growth, toxin production and alkaline phosphatase activity in lakes and streams. To assess the effect of nutrients on phytoplankton and biofilm community functions, a series of macro- and micronutrient enrichment experiments have been used both in situ and within bottle incubations. Quantification of enzyme activity, community composition and metabolic processes alongside growth permits assessment of what processes are limited or driven by these nutrients. By determining the magnitude of effect macro- and micronutrient enrichment has on various aquatic primary producer community processes, this work helps to fill the micronutrient knowledge gap in aquatic ecology and expand our understanding of the underlying physiological mechanisms controlling community and ecosystem level responses.

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

Increased blooms of cyanobacteria have been plaguing Lake Erie in recent decades, having profound negative impacts on the regional environment. These blooms deliver organic carbon to the lakebed, which can drive the consumption of oxygen and other oxidants through respiration within sediments. Emissions of the greenhouse gas methane from Lake Erie have been studied but have yet to be directly linked to eutrophication and sedimentary production in the Great Lakes. The hypothesis of this study is that cyanobacterial blooms in Lake Erie are contributing to an increase in methane fluxes from the lake to the atmosphere due to the process of sedimentary methanogenesis. Sediment and pore water data were analyzed from samples collected from two sites in the western basin during the 2021 and 2022 summer months. Findings suggest that methanogenesis is taking place at relatively shallow depths below the lakebed (within 10 centimeters of the sediment water interface). Thus, there is potential for substantial methane release to the water column. The shallow depth of methanogenesis also suggests that oxidants are being rapidly consumed within centimeters of the sediment water interface. The results of this study determined that eutrophication of Lake Erie is most likely contributing to methane production.