Doctor of Philosophy, The Ohio State University, 2013, Food, Agricultural and Biological Engineering

Too much of a good thing can become a problem. This is certainly the case with nutrients in surface waters. Excess nutrients are a concern in streams and lakes. While there are direct health risks related to drinking water contamination among vulnerable populations including infants, harmful algal blooms are a more prevalent concern since they manifest themselves at enrichment levels well below accepted drinking water standards. Half of the lakes in the United States have elevated nutrient levels, a condition that can ultimately lead to oxygen depletion. This problem is exported across state and national boundaries into coastal waters. Agricultural nutrient discharges are particularly difficult to address because, unlike end-of-pipe discharges, fertilizer runoff is hard to capture and treat in a cost effective manner. Appropriate technologies are needed that promote agricultural production through the sustainable management of natural resources. Treatment wetlands are a low-tech alternative to conventional water treatment. Constructed wetlands provide passive treatment of nutrient enriched runoff and other diffuse non-point sources of contamination through nutrient uptake, absorption, or chemical reduction. Hydraulic inefficiencies can substantially limit nutrient reductions when stagnant zones and preferential flow paths exist that reduce contact time. Optimally configured wetlands cost less and perform better. Unfortunately, it is not clear what constitutes an optimal configuration. Many factors, including shape, depth, and botanical structure, influence hydraulic efficiency. The various factors also influence each other, which makes it difficult to ascribe an effect to any one particular factor. Conventional investigative methods using controlled experiments focusing on a response to a single factor cannot tell the whole story. A more comprehensive approach is described here. Scaled models were used to investigate treatment wetland hyd (open full item for complete abstract)

Committee: Larry Brown (Advisor); Alfred Soboyejo (Committee Member); Norman Fausey (Committee Member) Subjects: Agricultural Engineering; Civil Engineering; Conservation; Ecology; Engineering; Environmental Engineering; Environmental Studies; Water Resource Management

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2024, Biological Sciences

Each chapter of this dissertation is intended to address a piece of the central hypothesis that complex, interacting biotic and abiotic filters drive community dynamics, including temporal synchrony between communities arising from distant propagule sources. In Chapter I, I examine the influence of three different synchrony metrics on measures of similarity between real and simulated time series, comparing methods for identifying clusters of more synchronous populations or communities, and revealing environmental drivers of those clusters. My results for this study indicate that wavelet analysis works best if the data have high frequency effects or high levels of noise. Empirical orthogonal functions work well if there are large differences in between-site magnitudes. If there are phase-lagged effects of interest, cross-correlation or empirical orthogonal function work well. For all other cases, each of these three metrics performed similarly. Therefore, these metrics may provide complimentary information if each are used to analyze the same dataset. Chapter II quantifies the filtering effects of temperature, egg bank composition, and disturbance on wetland invertebrate community dynamics and Chapter III quantifies the filtering effects of temperature, egg bank composition, and predation on wetland invertebrate community dynamics. Both chapters employ in-field mesocosm experiments in 100-gallon cattle tanks that were seeded with invertebrate propagules from either local ecosystems or from 5 different states. My results for these studies indicate that prairie pothole wetland communities are largely resistant to fluctuations in water levels though a few taxa (cladocerans, clam shrimp, fairy shrimp, damselfly larvae) saw decreased abundances in certain cases. Small changes in temperature (+1.1 °C) had little effect on the community except for intensifying the impact of the drawdown on clam shrimp and fairy shrimp. A greater change in temperature (+2.0 °C) led to more a (open full item for complete abstract)

Committee: Kevin McCluney (Committee Chair); Helen Michaels (Committee Member); Chris Patrick (Committee Member); Abby Braden (Other); Jeffrey Miner (Committee Member) Subjects: Biology; Conservation; Ecology; Entomology

Master of Science (MS), Ohio University, 2022, Environmental Studies (Voinovich)

There is a gap in access to sanitation in the US, particularly in rural areas such as Central Appalachia. The use of constructed wetlands as an alternative to onsite domestic wastewater treatment is one was to alleviate wastewater management challenges in small rural communities and work to close the sanitation gap. This study aimed to determine if year-round onsite wastewater treatment performance of constructed wetlands could be enhanced with the use of substrate and specialized operational modifications. Three constructed wetlands, with distinct substrates, organic, mineral, and combination, were used as treatment systems for a 4-month period, half above 15°C and half below 15°C. Results indicated a statistical difference between substrates in cold temperatures for TP and TKN and removal of many parameters in line with traditional wastewater treatment methods. This research supports the use of year-round wetlands to perform in the Central Appalachian region.

Committee: Michele Morrone Dr. (Committee Member); Natalie Kruse Dr. (Committee Chair); Guy Riefler Dr. (Committee Member) Subjects: Environmental Engineering; Environmental Health; Environmental Justice; Environmental Science

MS, Kent State University, 2019, College of Arts and Sciences / Department of Earth Sciences

Wetlands are complex ecosystems with unique biogeochemical and hydrological characteristics. These aspects can be traced to the following biogeochemically distinct domains: sediments, porewater, and surface water. Sulfur can play a critical role in aquatic ecosystems, with potential to influence the biogeochemical cycles of freshwater nutrients and metals. Inorganic sulfur can occur in the natural environment in multiple oxidation states. In the presence of oxygen, reduced sulfur readily oxidizes to form sulfate. Wetland hydrology controls the redox states of sulfur, as well as governing the fates trace metals, major cations, and anions in the wetland ecosystem. By examining wetland hydrology and characterizing the biogeochemistry of different wetland domains (sediment, porewater, and surface water), the export and forms of inorganic sulfur in the wetland can be characterized. The study site for this project was a constructed wetland at the Cleveland Metroparks' Watershed Stewardship Center in Parma, Ohio. The study site had interior zones of differing depths and a dynamic hydrologic regime, which could cause a variation in nutrient residence times and transformations within the wetland. To understand the wetland's hydrology and its relationship to sulfate biogeochemistry, interior water levels, outflow discharge, precipitation, water chemistry, sediment chemistry, and porewater chemistry were monitored from June 2015 to October 2016. High concentrations of sulfate were found in the interior zones (arithmetic mean: 185.7 mg/L) and outflow (arithmetic mean: 228.4 mg/L), while inflow concentrations were variable (ranges across inflows: 9.417-902.2 mg/L). Sulfate concentrations in surface water were found to be the highest in the interior and outflow following an extensive drydown period in Summer 2016. High concentrations of sulfate could also signal that sulfide was present in the wetland, but sulfide was below detection in porewater. However, wetland sediments c (open full item for complete abstract)

Committee: Anne Jefferson (Advisor); Lauren Kinsman-Costello (Advisor); Elizabeth Herndon (Committee Member) Subjects: Biogeochemistry; Environmental Geology; Environmental Management; Environmental Science; Freshwater Ecology; Geology; Hydrologic Sciences; Hydrology; Natural Resource Management; Water Resource Management

Master of Science (MS), Wright State University, 2018, Biological Sciences

Macroinvertebrates are important contributors to wetland ecosystems due to their role in decomposition, nutrient cycling, and as a food resource for other organisms. Several studies have analyzed the macroinvertebrate communities in created wetlands, but few have evaluated them in the context of trophic structure in both created and natural wetlands. The objective of this study is to better understand benthic macroinvertebrate community composition and trophic structure in created and natural wetlands. My central hypotheses were that macroinvertebrate communities in created wetlands would have (1) differing composition and (2) less complex trophic structure with shorter food-chain length compared to natural wetlands. Macroinvertebrates and soil cores were collected from five created and two natural depressional marshes. I assessed macroinvertebrate community characteristics such as diversity and composition, and functional feeding group composition. I used stable isotope analysis to determine food-chain length and other trophic metrics. Soil cores were used to determine bulk density, texture, and the C:N profile of the soil in the wetlands. Through a combination of univariate (e.g. ANOVA) and multivariate analyses (e.g. NMDS, PERMANOVA) these conclusions were met: (1) Macroinvertebrate taxa composition differed statistically between wetland types (p= 0.05); (2) FCL did not differ significantly between wetland types. In addition, functional feeding group composition was trending toward significance (p = 0.095), and soils were found to be distinct between wetland types (p= 0.043), with bulk density being a strong driver of that relationship (p= 0.012). These results show that in these wetlands, macroinvertebrate species present are different, however the overall function they provide are very similar between wetland types. The habitat characteristics in created wetlands that are known to quickly develop (e.g. plant community composition) were similar to the natural we (open full item for complete abstract)

Committee: Katie Hossler Ph.D. (Advisor); Yvonne Vadeboncoeur Ph.D. (Committee Member); Volker Bahn Ph.D. (Committee Member); John Stireman Ph.D. (Other) Subjects: Ecology; Entomology; Environmental Science; Environmental Studies

Doctor of Philosophy, The Ohio State University, 2014, Environmental Science

Emission and uptake of greenhouse gases and the production and transport of dissolved organic matter in different wetland plant communities are key wetland functions determining two important ecosystem services, climate regulation and nutrient cycling. The objective of this dissertation was to study the variation of methane emissions, carbon sequestration and exports of dissolved organic carbon (DOC) in wetland plant communities of a subtropical climate in south Florida. The plant communities selected for the study of methane emissions and carbon sequestration were located in a natural wetland landscape and corresponded to a gradient of inundation duration. Going from the wettest to the driest conditions, the communities were designated as: deep slough, bald cypress, wet prairie, pond cypress and hydric pine flatwood. Methane fluxes from the different communities did not show a discernible daily pattern, in contrast to a marked increase in seasonal emissions during inundation. Median and mean + standard error fluxes in g CH4-C.m-2.d-1 were higher in the deep slough (11 and 56.2 + 22.1), followed by the wet prairie (9.01 and 53.3 + 26.6), bald cypress (3.31 and 5.54 + 2.51) and pond cypress (1.49, 4.55 + 3.35) communities. The pine flatwood community acted as a net sink (0.0 and -1.22 + 0.81). Seasonality in methane emissions was positively correlated with the water levels, but not with soil temperature. However, longer inundation periods did not necessarily result in higher methane emissions. The mean carbon concentration from the surface to the depth of maximum 137Cs activity between communities was similar in the deep slough, bald and pond cypress (446, 405 and 369 g-C Kg -1, respectively). However, carbon sequestration rates (g-C.m-2.yr-1) were highest in the deep slough (104 + 14), followed by the pond cypress (60 + 9), bald cypress (30 + 2), wet prairie (24 + 1) and pine flatwood (15 + 1) communities, without an apparent relationship with the duration of the in (open full item for complete abstract)

Committee: William J. Mitsch Ph.D (Advisor); Gil Bohrer Ph.D (Advisor); James Bauer Ph.D (Committee Member); Jay Martin Ph.D (Committee Member) Subjects: Biogeochemistry; Climate Change; Ecology; Environmental Engineering; Environmental Management; Environmental Science; Environmental Studies; Hydrology; Natural Resource Management; Water Resource Management

MCP, University of Cincinnati, 2005, Design, Architecture, Art and Planning : Community Planning

This study evaluates legislative changes to Section 404 of the Clean Water Act and how these changes may impact “isolated” wetlands in Hamilton County, Ohio. This study considers current land use and makes assumptions about how the wetlands will be impacted given the current land use in relation to state law and permitting processes. This case is based on the January 2001, U.S. Supreme Court decision, Solid Waste Agency of Northern Cook County (SWANCC) v. United States Army Corps of Engineers. The decision eliminates federal protection of “isolated” wetlands under Section 404 of the Clean Water Act (CWA). The wetlands were formerly protected by the migratory bird rule. The permitting and review process is now administered by the States. The objective of this study is to understand how changes to the Clean Water Act may impact “isolated” wetlands in Ohio. The study is exploratory in nature and will focuses on parts of Hamilton County, OH. The author considers the permitting process administered by the Ohio EPA and makes predictions about how wetlands may have been if the legislation was never changed, and how the wetlands may now be affected because of this change. The author then makes recommendations on how to better protect the most at risk and valuable “isolated” wetlands in Hamilton County. The author draws on resources from the United States Environmental Protection Agency (USEPA), the United States Army Corps of Engineers (Corps), the United States Geologic Services (USGS), the Ohio Environmental Protection Agency (OHEPA), the Ohio Department of Natural Resources (ODNR), the State of Ohio Legislature (Legislature), the Ohio Revised Code (ORC), the Hamilton County Soil and Water Conservation District (SWCD), and the Cincinnati Area Graphics Information Systems (CAGIS) to make these predictions. By considering examples in Hamilton County, the author provides a framework for analysis of other wetlands in Ohio with similar criteria and potential threats.

Committee: David Edelman (Advisor) Subjects: Urban and Regional Planning

MCP, University of Cincinnati, 2002, Design, Architecture, Art, and Planning : Community Planning

Air travel has grown manifold in the last two decades (more than double), and so has the associated need to expand operations to meet the increased demand. Many airports in the past have been located on or near wetlands. In the light of these issues, this thesis explores wetland mitigation approaches employed by various large airports, considering increased capacity due to runway construction or expansion. Federal policy on wetlands requires "no net loss" of wetlands in acreage or ecological function. The Clean Water Act is the principle act protecting the wetlands in this country. Under the Section 404 of the Clean Water Act, wetland loss is to be avoided; if unavoidable, then impacts are to be minimized and, lastly, if neither of these options is possible, compensated for through mitigation. In the case of airports, where capacity increases must be made and the project site cannot be shifted, compensatory mitigation is usually required. Airports are interesting cases to study with regards to wetlands mitigation as they are governed by many regulations and regulatory bodies like the FAA, the EPA and the US Army Corps of Engineers - each of whom has a say in the mitigation process. The objectives of this study were to investigate the a) trends in wetlands mitigation as carried out by large airports around the country; b) identify factors that influence mitigation plans in these areas; and c) to recommend or make suggestions for preferred mitigation approaches to be employed by airports in the future. The study uses two approaches to research wetlands mitigation. One, a general survey of 17 large hub airports, was carried out; and for the second 3 airports - Atlanta Hartsfield International Airport, Cleveland Hopkins International Airport and Seattle Tacoma International Airport - were chosen for a case study analysis. They were chosen because they were large and medium hub airports that had in the past prepared Environmental Impact Statements (EIS) or were in the pr (open full item for complete abstract)

Committee: Dr. David Edelman (Advisor) Subjects: Urban and Regional Planning

Master of Science, University of Toledo, 2011, Biology (Ecology)

The impact of arsenic contamination is globally evident in agriculture and industry. Current methods for arsenic removal have several limiting factors that include usage of large amounts of energy and production of a contaminant by-product. Treatment wetlands are an alternative, sustainable method of contaminant removal that are successful in removing organic contaminants from water, but have not yet been used for arsenic remediation. In this study, small scale (0.57 m x 0.17 m x 0.17 m) test cells were constructed to assess the ability of wetlands to remediate arsenic contaminated water. We have proposed a conceptual model that envelops the potential remediation processes, including soil, plants and microorganisms, within a treatment wetland for arsenic removal. At the root of these processes is the flow of water that transports arsenic-laden water to each component of the wetland. In this experiment, my aim was to predict the transport of arsenate, the species of arsenic with the greatest adsorption capacity, within the soil and water compartments of the treatment wetland test cells. This will be accomplished with the following objectives: iv (1) use a bromide tracer test to characterize water movement within the test cells, (2) characterize the ability of the soil to adsorb arsenate and (3) predict the fate of arsenate in the cells using these data in an appropriate transport model. Test cells were constructed with a sandy loam soil, packed to a field bulk density of 1.5 g cm-3. The computer program, HYDRUS 2D, was selected as the model, because of its capacity to simulate water and solute transport in soil, and its ability to be calibrated using the obtained data. A tracer test using bromide and water samplers embedded within the soil determined that the water was flowing to all the regions of the test cells. An arsenate adsorption experiment to assess arsenate concentration using ICP-OES found the soil was capable of adsorbing arsenate with a maximum capacity o (open full item for complete abstract)

Committee: Daryl Dwyer PhD (Advisor); Defne Apul PhD (Committee Member); Alison Spongberg PhD (Committee Member); James Martin-Hayden PhD (Committee Member) Subjects: Environmental Engineering; Environmental Science; Environmental Studies

Doctor of Philosophy, The Ohio State University, 2012, Environment and Natural Resources

Wetland ecosystems are significant carbon sinks. Their high productivity and presence of water gives them the ability to efficiently sequester carbon in the soil, serving as a potential tool to mitigate the net greenhouse effect of carbon emissions to the atmosphere and abate climate change. We explored the efficiency of freshwater wetlands sequestering carbon under different climates, wetland types, and vegetation communities, in order to assess the conditions that favor carbon accumulation. We also studied the ability of created freshwater wetlands to sequester carbon and the effect of their vegetation communities on this task. We found significant differences on carbon sequestration between wetland types in temperate and tropical regions, being consistently higher in the studied forested wetlands (260 ± 58 gC m-2 y-1) than the riverine ones (113 ± 27 gC m-2 y-1), indicating the importance of wetland productivity and the type of organic matter entering the system. Our temperate wetlands were also consistently more efficient in sequestering carbon than similar tropical ones (233 ± 89 and 151 ± 57 gC m-2 y-1, respectively), suggesting that higher temperatures in tropical climates may hinder carbon sequestration by intensifying organic matter decomposition rates. Within the tropical climates, we found that the tropical humid wetland sites had significantly higher carbon sequestration rates (306 ± 77 gC m-2 y-1) than those located in the tropical dry regions, were there is a marked wet and dry season (63 ± 10 gC m-2 y-1 on average). Our comparison between vegetation communities show that wetland productivity and permanent anaerobic conditions are key in enhancing soil carbon sequestration, being 214 ± 54 gC m-2 y-1 in the open water sites (with prolonged anaerobic conditions) and 184 ± 72 gC m-2 y-1 in the edges (typically more productive due to their fluctuating water levels). In the tropics, where temperature might to be a limiting factor for carbon sequestration (open full item for complete abstract)

Committee: William J. Mitsch (Advisor); Rattan Lal (Committee Member); Richard P. Dick (Committee Member); Eric Toman (Committee Member) Subjects: Environmental Science

Master of Science, The Ohio State University, 2009, Environmental Science

Constructed, created and restored wetlands are gaining popularity due to multiple benefits they provide. However, there is a concern that wetlands increase mosquito breeding in urban areas. This is especially due to the recent concern regarding mosquito borne viral encephalitis and other diseases. Published studies to quantify mosquito population in constructed and natural wetlands are inconclusive. This study quantified the population of mosquitoes from two experimental flow-through created wetlands and two stormwater fed wetland at the Olentangy River Wetland Research Park (ORWRP) in Columbus, Ohio in summer. Sampled mosquitoes were identified to species level to investigate their disease vector potential. The study also compared mono specific and multispecies small (1 m2) mesocosms being used for another experiment. The flow-through created wetlands were less conducive to mosquito breeding compared to the pond (p<0.00001) and stormwater wetland (p=0.002). Outflow regions and emergent vegetation sites in the flow-through wetlands were most conducive to mosquito breeding than were inflows (p=0.009) and floating vegetation sites (p=0.023). Mixed vegetation communities (Sparganium eurycarpum, Juncus effusus, and Schoenoplectus tabernaemontani) rather than mono specific Typha communities provided most conducive environment for mosquito breeding (p<0.0001). Mesocosm plots with steady inflow (10 cm depth) and with deep water (20 cm) in summer and shallow water (5 cm) in spring had higher mosquito densities than did mesocosm plots with pulsed flow (10 cm depth with inflow rate according to the river stage) and deep water (20 cm) in spring and shallow water (5 cm) in fall. Among water quality parameters, conductivity (p=0.004) and, to a lesser extent, dissolved oxygen (p=0.052) correlated with mosquito larval density (adjusted R2 of 0.67). Six mosquito species identified in all water bodies were Cx. pipiens, Cx. salinarius, Cx. restuans, Ur. sapphirina, An. quadrimaculatu (open full item for complete abstract)

Committee: Parwinder Grewal PhD (Advisor); Timothy Buckley PhD (Committee Member); Woodbridge A. Foster PhD (Committee Member); William J. Mitsch PhD (Committee Member) Subjects: Environmental Science

Doctor of Philosophy, The Ohio State University, 2009, Environmental Science

Wetlands are important ecosystems in our landscape because of the broad array of ecosystem services they provide to humans and the environment. Wetlands have unique biotic and abiotic chemical interactions among soil, water, and vegetation that, combined with long retention times that are characteristic of wetlands, allow for nutrients, metals, and organic pollutants to be removed from the water column, resulting in cleaner water. The same characteristics that make wetlands so efficient at improving water quality also provide anaerobic conditions and organic substrate that is optimal for methanogenesis, the microbial production of the greenhouse gas (GHG) methane (CH4). The objective of this dissertation is to investigate the biogeochemistry, specifically water quality improvement and CH4 emissions, of natural and created wetlands in tropical and temperate climates. Five tropical treatment wetlands dominated by floating aquatic plants and constructed to deal with a variety of wastewaters were compared for their effectiveness in treating organic matter and nutrients in the Parismina River Basin in eastern Costa Rica. Wastewaters were from a dairy farm, a dairy processing plant, a banana paper plant, and a landfill. Four of the five wetland systems were effective in reducing nutrient levels of effluents before water was discharged into rivers. Ammonia nitrogen (N) levels in water entering most wetlands were considerably higher than ambient (i.e., riverine) levels; concentrations were reduced by as much as 92% in the wetlands, which retained, at a maximum, more than 166 g NH4-N m-2 y-1. Nitrate N removal occurred in low concentrations in the inflows (less than 1 mg-N L-1). Phosphate phosphorus (P) was effectively reduced through the wetlands (92 and 45% reductions through dairy farm wetlands, 83% reduction through banana paper wetlands, and 80% reduction through dairy processing wetlands). Retention of phosphate ranged from 0.1 to 10.7 g-P m-2 year-1 in the treatment (open full item for complete abstract)

Committee: William J. Mitsch PhD (Advisor); Nicholas T. Basta PhD (Committee Member); Richard P. Dick PhD (Committee Member); Jay F. Martin PhD (Committee Member) Subjects: Biogeochemistry

Master of Science, The Ohio State University, 2008, Natural Resources

Wetlands are a large terrestrial carbon pool and play an important role in global carbon cycles as natural carbon sinks. Previous carbon studies have mainly focused on boreal peatlands; little is known about carbon pools in temperate and tropical wetlands and their soil profiles. This study analyzes the variation of soil carbon with depth in two temperate (Ohio) and three tropical (humid and dry) wetlands in Costa Rica, and compares their total soil C pool as a first step toward determining C accumulation in wetland soils. The results indicate that these temperate wetlands have significantly greater (P < 0.01) C pools (17.6 kg C m-2) than wetlands located in tropical climates (9.7 kg C m-2) in the top 24 cm of soil. Carbon profiles showed a rapid decrease of concentrations with soil depth in the tropical sites, whereas in the temperate wetlands they tended to increase with depth, up to a maximum at 18-24 cm, after which they started decreasing. The two wetlands in Ohio had about ten times the mean total C concentration of adjacent upland soils (e. g., in Gahanna Woods, 161 g C kg-1 were measured in the wetland, and 17 g C kg-1 in the upland site), and their soil C pools were significantly higher (P < 0.01). Among the five wetland study sites, three main wetland types were identified – isolated forested, riverine flow-through, and slow-flow slough. In the top 24 cm of soil, isolated forested wetlands had the greatest pool (10.8 kg C m-2), significantly higher (P < 0.05) than the other two types (7.9 kg C m-2 in the flow-though and 8.0 kg C m-2 in the slough), indicating that the type of organic matter entering into the system and the type of wetland may be key factors defining its soil C pool. The flow-through wetland in Ohio (Old Woman Creek) showed a significantly higher C pool (P < 0.05) in the permanently flooded location (18.5 kg C m-2), than in the edge location with fluctuating hydrology, where the soil is inttermitently flooded (14.6 kg C m-2).

Committee: William Mitsch (Advisor); Rattan Lal (Committee Member); Richard Dick (Committee Member) Subjects: Ecology; Environmental Science; Soil Sciences

Doctor of Philosophy, The Ohio State University, 2006, Environmental Science

The effect of hydrologic conditions on nitrogen biogeochemistry was investigated in two identical 1-ha surface-flow created riverine wetlands in Columbus, Ohio, USA. These wetlands, created in 1993-1994, are fed with water from Olentangy River. For two years (2003-2004), both wetlands experienced seasonal (winter-spring) controlled hydrologic flood pulses followed by one year (2005) in which they received a steady flow rate of water. Nitrogen gas flux measurements were made in plots distributed along a transverse gradient (edge plots and high marsh plots with alternate wet and dry conditions, and low marsh plots and open water plots with permanent flooding). Highest average N2O fluxes were observed in high marsh plots followed by edge plots, open water plots , and low marsh plots. In permanently flooded plots without vegetation, nitrous oxide fluxes were low, regardless of flood pulse conditions.N2O fluxes were higher in plots with vegetation than in plots without vegetation only when plots were inundated. Denitrification in all plots was significantly correlated with soil temperature and was significantly correlated with the nitrate concentration in the inflow surface water in the growing season in permanently flooded zones. Highest mean denitrification rates were observed in the low marsh and open water zonesfollowed by high marsh and edge zones. In permanently flooded areas, denitrification rates were significantly higher near the inflow than near the outflow. Denitrification appeared to be nitrogen limited in low marsh, high marsh and edge plots, but both carbon and nitrogen limited in open water. NO2- + NO3- mass retention was similar under pulsing and steady flow conditions. Total nitrogen (TN) retention was lower under pulsing than steady flow conditions as a result of an export of organic nitrogen occurred under pulsing conditions. Aboveground biomass productivity in the pulsing year was significantly lower than in the steady-flow flow. Belowground biomass p (open full item for complete abstract)

Committee: William Mitsch (Advisor) Subjects:

Master of Science, The Ohio State University, 2008, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2005, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, Miami University, 2024, Biology

Ephemeral wetlands, which are dominated by amphibians, have been destroyed to make room for agriculture, which increases the risk of contamination from pesticide use. One of the most widely used insecticides in the US is the neonicotinoid, imidacloprid. While the direct effects of imidacloprid on amphibians are sublethal, indirect effects may be conferred through disruptions in the food web. These effects may be dependent on the structure of the community. The objective of this study was to determine the effects of imidacloprid in communities that differ in food web structure (communities without amphibians; communities with northern leopard frogs [Lithobates pipiens]; communities with northern leopard frogs and spotted salamanders [Ambystoma maculatum]) on biomass of each tropic level and amphibian outcomes at metamorphosis. This experiment was conducted in outdoor mesocosms located in Oxford, Ohio. My study demonstrated that the trophic position of amphibians affected the impact of imidacloprid–negatively impacting salamanders, while having no or positive effects on anurans. Anurans had positive effects on other community members when imidacloprid was present. My research demonstrated how the complexity of the food web can alter the impact of an insecticide on biomass produced and the movement of resources from the aquatic to terrestrial systems.

Committee: Michelle Boone (Advisor); Michael Vanni (Committee Member); Hank Stevens (Committee Member) Subjects: Aquatic Sciences; Biology; Ecology; Freshwater Ecology; Wildlife Conservation

Master of Science (MS), Ohio University, 2024, Environmental Studies (Voinovich)

Growing human population has led to an accelerated rate of degradation of natural resources. One of the most alarming impacts is water quality impairment globally as a result of nutrient pollution from agricultural and other non-point sources. This study assesses the efficiency of wetland restoration project in mitigating nutrient pollution in the Bell Run-South Fork Licking watershed in Ohio. Nutrient pollution, primarily stemming from nitrogen and phosphorus runoff from agricultural activities poses water quality challenges to the region. The restoration of an 80-acre portion wetland aims to ultimately improve the water quality of the Soth Fork Licking River by reducing nutrient loading into Bloody Run and its tributaries. Through pre- and post-construction assessments, the study evaluated changes in nutrient concentrations and hydrological inputs. Results indicate significant reductions in nitrogen species loading postconstruction. However, there was an increase in phosphorus loading following the construction period. Hydrological inputs' to the site influences on nutrient dynamics were evident, with storm events leading to higher nutrient discharge. Continued monitoring during high-flow periods is recommended to improve understanding of nutrient dynamics within the restored site and inform management strategies for optimizing the wetland's nutrient retention capacity over time.

Committee: Natalie Kruse (Committee Chair); Sarah Davis (Committee Member); Daniel Che (Committee Member) Subjects: Environmental Studies