Physical Sciences and Mathematics Commons^™

Quantifying Terrestrial Ecosystem Carbon Dynamics With Mechanistically-Based Biogeochemistry Models And In Situ And Remotely Sensed Data, Shaoqing Liu

Open Access Dissertations

Terrestrial ecosystem plays a critical role in the global carbon cycle and climate system. Therefore, it is important to accurately quantify the carbon dynamics of terrestrial ecosystem under future climatic change condition. This dissertation evaluates the regional carbon dynamics by using upscaling approach, mechanistically-based biogeochemistry models and in situ and remotely sensed data.

The upscaling studies based on FLUXNET network has provided us the spatial and temporal pattern of the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important physiological role in carbon assimilation. In the second chapter, we consider the effect of atmospheric CO2 …

Lower Food Web Dynamics In Lakes Michigan And Huron: Spatial And Temporal Responses To Recent Oligotrophication, Margaret Hutton Stadig

Open Access Theses

Nutrient abatement programs, originally enacted to counter eutrophication have successfully suppressed nutrient loads and relative primary production in marine and freshwater systems. Recently, the additive impacts of invasive filter feeders have further reduced offshore primary production in several aquatic systems throughout the world. It has been hypothesized that the biological activity of these invasive species may sequester nutrients within the nearshore benthic environment, creating steep gradients in primary production between nearshore and offshore habitats. In the Laurentian Great Lakes, past studies of oligotrophication have primarily focused on food web responses in offshore habitats. Organisms at higher trophic levels have been …

Mathematical Analysis Of Feedback Targets Of Bmp Signaling In Drosophila Embryonic Development, Yan Luo

Open Access Theses

Bone morphogenetic proteins (BMPs) drive a range of cellular processes especially in the early stages of embryonic development. This family of proteins acts as one of the most important extracellular signals in development pattern formation across the animal kingdom. Cells in embryos differentiate into different cell types in response to the concentration level of BMP. This complex process is regulated by multiple regulators that serve to tune the signal response.

Extensive experimental and computational research has been performed to analyze BMP regulation in Drosophila, a widely studied model organism, and has advanced our understanding of animal development. Because of …

Gonadal Intersex In Teleosts: Mechanisms, Molecular Biomarkers And Diagnostic Assays, Ahmed M.E. Abdel-Moneim Mohamed

Open Access Dissertations

Natural and synthetic estrogenic and androgenic compounds are continuously released into aquatic ecosystems. Exposure of teleost fishes to these contaminants can negatively impact sex differentiation and reproductive output. Specifically, development of gonadal intersex in gonochoristic (fixed sex) fish species has been studied extensively in relation to exposure to this class of compounds. The main objectives of this dissertation were to: 1) conduct field and laboratory studies to investigate the molecular signaling pathways behind the development of gonadal intersex; and 2) establish molecular biomarkers and assays for testing the ability of environmental pollutants to develop this condition using a battery of …

Intestinal Adaptation To Repeated Exposure Of Flavonoid-Rich Foods: In Vitro And Clinical Data, Bejamin W. Redan

Open Access Dissertations

Interest in application of flavonoids for chronic disease prevention has grown significantly, but the low oral bioavailability of these compounds from acute doses is commonly highlighted as a limitation when considering their biological significance. Still, the impact of broad dietary patterns such as repeated exposure on flavonoid’s absorption, metabolism, and eventual efficacy is critical to consider since evidence suggests that their bioavailability may be enhanced with repeated exposure. To fill this gap in knowledge, this dissertation will focus on three major areas including characterization of flavonoid metabolites, in addition to use of in vitro models and clinical work to test …

Manufacturer Perspectives On Content Transparency And Material Health In The Us Building Products Industry, Alexandra A. Muller

Open Access Theses

Flawed U.S. federal regulation of chemicals has resulted in a materials market that undervalues human and environmental health in favor of the more traditional attributes of price, performance and aesthetics. In the building products industry, global, dynamic supply chains and proprietary information concerns further complicate the task of assessing the material health of products.

Voluntary material health programs in the green building industry are intended to incentivize the manufacture and selection of safer products by getting companies to gather and assess ingredient, hazard and risk information from their supply chain. Building product manufacturers considered early adopters of the main material …

Nutrient Runoff And Leachate After Land-Application Of Digestate In A Laboratory Study Using Rainfall Simulations, Min Xiao

Open Access Theses

There has been an increasing number of anaerobic digesters on livestock farms in the United States during the past two decades. Anaerobic digestion of manure allows production of renewable energy and generation of stabilized and nutrient-rich digestate that can be used as organic fertilizer. However, the majority of the existed studies using liquid digestate as fertilizer only focused on the effectiveness for crop yield, nutrient content and microorganism in soil. There is insufficient understanding in the environmental impact of digestate land-application. This laboratory study used six treatments including four different liquid digestate treatments, a chemical fertilizer treatment, and an unfertilized …

Behavioral Responses And Policy Evaluation: Revisiting Water And Fuel Policies, Shanxia Sun

Open Access Dissertations

In my dissertation, I examine how policies regulating agricultural production and clean technology impact the environment. I focus on policies affecting water depletion, water pollution, and fuel consumption. I assess their cost-effectiveness by modeling and quantifying the behavioral responses of farmers and households.

My first essay focuses on decreasing groundwater depletion through increasing irrigation efficiency in Mexico. I quantify the impacts of different sources of inefficiency on groundwater extraction, and I evaluate the effectiveness of alternative policies that aim to reduce the over-extraction of groundwater. I find that mechanisms of electricity cost-sharing implemented in many wells have a sizable impact …

Economic And Environmental Impacts Of A Hypothetical Global Gmo Ban, Harrison H. Mahaffey

Open Access Theses

The objective of this research is to assess the global economic and greenhouse gas emission impacts of GMO crops. This is done by modeling two counterfactual scenarios and evaluating them apart and in combination. The first scenario models the impact of a global GMO ban. The second scenario models the impact of increased GMO penetration. The focus is on the price and welfare impacts, and land use change greenhouse gas (GHG) emissions associated with GMO technologies. Much of the prior work on the economic impacts of GMO technology has relied on a combination of partial equilibrium analysis and econometric techniques. …

Investigating U.S. Resident Perceptions Of Corporate Social Responsibility In Food And Agriculture, Carissa Jae Morgan

Open Access Theses

Corporations are prioritizing corporate social responsibility (CSR) activities by investing in and actively promoting their social practices. In the U.S. of the modern food supply chain creates a unique challenge for corporations to address concerns about social issues of consumers and non-consumers alike. This study is motivated by the need to better understand individuals’ perceptions of CSR as it pertains to the food supply chain. In April 2015 an online survey collected information from 1,201 U.S. residents with the objective of investigating individuals’ perceptions of relative importance of eight prominent CSR areas relevant to food and agriculture. Demographic, household consumption, …

Deforestation Of Cloud Forest In The Central Highlands Of Guatemala: Soil Erosion And Sustainability Implications For Q'Eqchi' Maya Communities, Ian Christopher Pope

Open Access Theses

Understanding the nexus between deforestation, food production, land degradation, and culture contributes knowledge that is useful for development practitioners working to enhance conservation and food security. Documenting deforestation and soil erosion in the Sierra Yalijux and Sierra Sacranix in the Central Highlands of Guatemala adds new knowledge about the rates and dynamics of deforestation and land degradation in areas with unique and sensitive cloud forest ecosystems. It also suggests possible areas of emphasis for efforts targeted at combining cloud forest conservation with sustainability for indigenous Q'eqchi' communities. In addition, this work contributes to a small but growing body of literature …

Pharmaceuticals And Personal Care Products: Emerging Contaminants In Aquatic Ecosystems, Jenny E. Zenobio

Open Access Theses

In recent years, the presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems has led to research on their fate and effects. PPCPs have been found in mixture in wastewater effluents, surface, ground, and drinking water at low concentrations from areas of intense urbanization. Although adverse effects to human health from the current environmental concentrations are unlikely, the impacts to ecological receptors are not clear. We performed field and laboratory studies to quantify and evaluate effects of PPCPs on fish. First, a field study was conducted at the Baca National Wildlife Refuge, Colorado (2010-2012) because a portion of …

Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr

Open Access Dissertations

The shift to concentrated animal production facilities and increasing rural-urban migration has increased the localized land application of nearly 1 billion tons of manure and biosolids annually. Although these applications provide nutrients and contribute to soil tilth, they also serve as a source for an estimated 49 tons of the natural manure-borne estrogens, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), and estrone (E1). While these estrogens are critical to endocrine systems, the low concentrations observed in the environment can disrupt endocrine function in non-target organisms, e.g., altering secondary sex characteristics which can lead to changes in wildlife communities.

Research presented here focuses on …

Developing White Ash With Resistance To The Emerald Ash Borer, Kaitlin Joy Palla

Open Access Theses

Hypocotyls isolated from mature embryos germinated on Murashige and Skoog (MS) medium supplemented with 22.2 µM 6-benzyladenine (BA) and 0.5 µM thidiazuron (TDZ) were transformed using Agrobacterium tumefaciens strain EHA105 harboring the pBI121-8D2 vector containing the neomycin phosphotransferase (nptII) gene and a full length, codon-optimized Bacillus thuringiensis Cry8Da protoxin gene (cry8D2). Explants were transformed in a bacterial suspension with 100 µM acetosyringone using 90 s sonication and 10 min vacuum-infiltration. Four independent lines of transformed shoots were selectively regenerated on MS medium with 22.2 µM BA, 0.5 µM TDZ, 50 mg L^-1 adenine sulfate, 10% …

Habitat Restoration Of A Constructed Ohio River Embayment, Caleb Michael Rennaker

Open Access Theses

Backwater habitats of large rivers provide habitat for aquatic biota and influence important predator-prey interactions in fishes and other aquatic organisms. However, these areas often exhibit turbid conditions and lack habitat complexity. Restoration of lentic habitats through direct habitat manipulations has shown success in prior efforts, but these methods have not been tested in backwater habitats of large rivers. I attempted to create habitat in an Ohio River embayment by establishing founder colonies of aquatic macrophytes coupled with the placement of underwater gravel beds. I also evaluated the effects of total suspended solids (TSS) on overwintering structures of American Pondweed …