Physical Sciences and Mathematics Commons^™

Effects Of Elevated Temperature On Gonadal Functions, Cellular Apoptosis, And Oxidative Stress In Atlantic Sea Urchin (Arbacia Punctulata), Jackson B. Johnstone

Theses and Dissertations

Increasing surface sea water temperatures effect on growth, reproduction and development in marine organisms. Sea urchins are excellent indicator species and ideal model organisms to focus on. In this study, I tested the effect of higher temperatures on reproductive functions, heat shock protein (HSP, a chaperone protein produced by cells in response to heat stress) and nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS) expressions, cellular apoptosis, and ceolomic fluid (CF, a body fluid which regulates important physiological processes) conditions in Atlantic sea urchin at three different temperatures. Ten sea urchins were placed in each of six aquariums …

A Snapshot Of The Age, Growth, And Reproductive Status Of Gray Triggerfish (Balistes Capriscus, Gmelin 1789) On Three Artificial Reefs In The Northwest Gulf Of Mexico, Adam M. Lee

Theses and Dissertations

Age, growth, and reproductive status of gray triggerfish (Balistes capriscus) were identified from 2015-2016 on artificial reefs in the northwest Gulf of Mexico. Individuals ranged from 232-432 mm fork length with and a mean fork length of 319 mm. Individuals from age 0.2 to 5.2 yrs were observed with a weight to length relationship of Wg = 1.1 x -104 x FL2.7 (r2 = 0.94, n = 112), where FL = fork length (mm) and Wg = weight (g). A von Bertalanffy growth equation of Lt = 326(1 - e - 0.9 (t + 1.71)) was calculated irrespective …

Effects Of Global Warming On Gonadal Functions, Cellular Apoptosis, And Oxidative Stress In The American Oyster, Sarah B. Nash

Theses and Dissertations

Global warming due to climate change is predicted to intensify the heat stress in marine and coastal organisms, affecting their development, growth and reproductive functions. In this study. I analyzed gonadal development, heat shock protein 70 (HSP70), nitrotyrosine protein (NTP), dinitrophenyl (DNP) expressions, cellular apoptosis, and coelomic fluid (CF) conditions in American oyster. Oysters were placed in six aquariums and exposed to control (24°C), medium (28°C), and high (32°C) temperatures for one week. Higher temperature significantly decreased the number of eggs and sperm. CF protein concentrations also declined compared to control. In contrast, CF pH and HSP70 expression in gonad …

Impacts Of Habitat Attributes And Community Gardens On Urban Bird Communities, Samuel Glenn Ortiz

Theses and Dissertations

The Rio Grande Valley of Southern Texas is a major agricultural region yet has some of the highest hunger rates in the USA. Urbanization and agriculture affect biodiversity, which is well studied, but little is known about how agriculture affects biodiversity in urban areas. We investigated how different urban attributes, including those related to urban farming, impact bird communities in Brownsville and Harlingen, TX, and compared sites that have community gardens to those that do not. To study three key urban habitat characteristics, we identified sites that exhibited all possible combinations of these factors, quantified land cover classes related to …

Measuring Connective Capacity Throughout The Gulf Of Mexico Fishery Management Network, Anthony Rocha Lima

Theses and Dissertations

The Gulf of Mexico provides substantial resources along its 1,680-mile coastline, spanning 5 U.S. states and providing millions of pounds of seafood and hundreds of millions in revenue annually. Continued success of the fishery relies on the ability of a large, complex, multiagency network to find the best solutions to balance the needs of humans, as well as ensure long-term sustainability. Organizations with varying objectives require effective communication when addressing intricate ecosystem-based management topics such as endangered species and regional economies.

To better understand the connectivity within the Gulf fishery management network, an IRB reviewed survey was dispersed to the …

Longitudinal And Temporal Comparison Of Beach Sand On The Rio Grande Delta System, Samantha B. Moore

Theses and Dissertations

The Rio Grande is the 5th longest river in North America and defines a significant extent of the United States-Mexico border. It extends for 2830 km from its headwaters in the Rocky Mountains of Colorado to the Gulf of Mexico. The Rio Grande is fed by streams from the Sangre de Cristo Mountains, the Rio Conchos, the Pecos River, runoff from the Sacramento Mountains area, Devils River, the Rio Salado, and the Rio San Juan. This study addresses how the composition of sand forming the Rio Grande river delta into the Gulf of Mexico at Boca Chica Beach is changed …

Characterizing Polychlorinated Biphenyl Degradation Potential In Surface Water Bacteria From Rio Grande Valley, Texas Reservoirs, Alisha M. Janiga

Theses and Dissertations

The Donna Reservoir in Donna, Texas is contaminated with polychlorinated biphenyl (PCB) pollution. This reviews the current understanding of PCBs and investigate the potential of PCB degradation by native bacteria communities in the Donna Reservoir. The metabolic diversity, biphenyl tolerance, bphA1 presence were tested on surface water samples from the Donna Reservoir. The Ecoplate data suggest that the communities have a diverse metabolic capacity and the degree of plant life may interact with carbon type metabolism but not the rate of growth. Biphenyl growth curves showed that all the samples from the Donna Reservoir are tolerant to the average PCB …

Development Of Lower Rio Grande River Water Quality Transportation Numerical Model For Bi-National River Management, Jose O. Gonzalez

Theses and Dissertations

Traditionally, water quality modelling has focused on modelling individual water bodies. However, water quality management problems must be analyzed at the larger scale to include influences from various water bodies that are interconnected. This paper provides a study on the hydrologic and quality transportation calculation by developing a hydrodynamic (unsteady state) channel routing model using a water-balanced approach. A one dimension Lagrangian river model was developed and applied to the 210 plus miles for the lower Rio Grande River Basin from the Falcon Dam to the head water of Brownsville that pours onto the Gulf of Mexico. This model can …

Investigating The Application Of Multibeam Sonar And Remotely Operated Vehicles In Fish Population Monitoring On Artificial Reefs, Robert Figueroa-Downing

Theses and Dissertations

Implementation of ROVs and multibeam imaging sonar in fisheries research has the potential to improve the accuracy and efficiency of current monitoring practices. This study aimed to 1) compare ROV video and diver abundance estimates; 2) evaluate fish length measurement accuracy from sonar; 3) investigate key differentiating sonar characteristics. Results indicate: 1) Diver surveys captured greater diversity of species; survey methods were comparable with regards to conspicuous species (r = 0.089, p = 0.074); 2) Length measurements from multibeam imaging sonar had high predictive power (Rho = 0.998; p < 0.001) of actual standard lengths and; 3) variations between samples were largely due to swim bladder echo, relative position of the target fish, and schooling characteristics. We conclude that 1) ROVs are less apt at observing cryptic species; 2) The Blueview P900-90 sonar can accurately measure fish length; and 3) swim bladder morphology plays an important role in fish identification.

Unraveling The Fingerprints Of Nox Using Stable Isotopes: Implications For Nox Source Partitioning And Oxidation Chemistry, Wendell William Walters

Open Access Dissertations

The nitrogen (N) and oxygen (O) stable isotope composition (δ15N & δ18O) of nitrogen oxides (NOx )may be a useful tool for constraining NOx emission sources as well as for understanding the atmospheric oxidation pathways responsible for its removal if various NOx sources and sink processes exhibit characteristic isotopic compositions (“fingerprints”). However, this requires (1) an accurate and complete inventory of δ15N(NOx) values from major emission sources, (2) an assessment of the kinetic and equilibrium isotope effects that can impact δ15N and δ18O values of NOx, (3) and test these assumptions by conducting accurate in situ δ15N and δ18O measurements …

Liming Characteristics Of A High-Calcium, Dry Flue Gas Desulfurization By-Product And Its Effects On Runoff Water Quality, Jason Richard Burgess-Conforti

Graduate Theses and Dissertations

In 2013, only 37% of the 32 million Mg of flue gas desulfurization (FGD) by-products generated in the United States were reused beneficially. If FGD by-products could be used as a beneficial soil amendment, millions of megagrams may be diverted away from surface impoundments and landfills. The purpose of this research was to identify the liming characteristics of a high-Ca dry FGD (DFGD) by-product in comparison to a Class-C fly ash (FA) and reagent-grade CaCO3, and to evaluate the effects of land application to a managed grassland on runoff, plant, and soil quality. Liming characteristics were determined by measuring the …

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …

Optical Water Quality And Human Perceptions Of Rivers, Amie West

Graduate Theses and Dissertations

Understanding water quality dynamics in recreational rivers is integral in shaping management strategies that maintain ecosystem health, perceived value and appeal, and regional economic significance in a changing environment. Optical water quality describes the behavior of light in water as governed by its physical and chemical composition, and is among the strongest influences on human perceptions of water quality. Ethnohydrology is the study of culturally constructed knowledge and understanding of water. This work is the culmination of an interdisciplinary approach to water resources research—integrating optical water quality and ethnohydrology methods to recognize the intersection between measured water quality and visible …

The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii

Graduate Theses and Dissertations

Organic matter (OM) in the environment acts as a nutrient, but may also act as a transport vector for harmful chemical compounds and bacteria. Acetate is a labile form of OM produced during fermentation in anaerobic lagoons used to store animal fecal-waste from concentrated animal feeding operations (CAFOs). Dry and liquid fertilizers from CAFOs pose a threat to groundwater by introducing excessive amounts of nutrients (e.g. OM, nitrate and ammonia), metals, and antibiotic compounds. In the epikarst of Northern Arkansas in the Buffalo River watershed additional input of labile dissolved organic carbon (DOC) from liquid CAFO waste-fertilizers was hypothesized to …

South Padre Island Beach Management: Assessment Of Dune Restoration, Shelby Rose Bessette

Theses and Dissertations

Dune restoration is a common method of increasing coastal resilience. A dune restoration program was initiated by the City of South Padre Island, TX in 2010 consisting primarily of plantings of Sea Oats, Uniola paniculata, and Bitter Panicum, Panicum amarum and has continued approximately annually thereafter. These restoration efforts were evaluated in this study by comparing dune ecological structure and function among reference sites and restoration plots ranging in age from 2 to 5 years. Plant and animal communities were examined using a combination of quadrat sampling, funnel traps, pit-falls and sweep nets. Soil organic content and soil electric …

Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon

Graduate Theses and Dissertations

The accurate estimation of soil erosion by the Revised Universal Soil Loss Equation version 2 (RUSLE2) is critical for several conservation assessments, least of which is its use in the Phosphorus Index (PI) to identify and rank the vulnerability of agricultural fields to phosphorus (P) runoff. Earlier versions of RUSLE reported a soil loss overestimation, which were revised to give RUSLE2, where biomass production in different climatic regions was more accurately represented. RUSLE version 2.0, which contains the new vegetative biomass production routine, was evaluated using two performance indices, the Nash Sutcliffe Efficiency Index (NSE) and Index of Agreement (D) …

Quantifying The Global N2o Emissions From Natural Ecosystems Using A Mechanistically-Based Biogeochemistry Model, Tong Yu

Open Access Theses

Nitrous oxide (N2O) has a great influence on atmospheric chemistry and climate. It is not only a major greenhouse gas, but also one of the largest ozone-depleting substances emitted from the biosphere. Process-based biogeochemistry modeling constrained by site-level observations is a feasible approach to quantifying its emissions at large temporal and spatial scales. This study developed a process-based biogeochemistry model of N2O emissions based on an extant biogeochemistry model, the Terrestrial Ecosystem Model (TEM). The model development includes: 1) incorporating the effects of physical conditions on both nitrification and denitrification and 2) implementing principles of the stoichiometry of carbon and …

Watershed Delineation In The Field: A New Approach For Mobile Applications Using Lidar Elevation Data, Samuel Adam Noel

Open Access Theses

With the advancement of mobile devices, opportunities to take watershed management tasks out of the office and into the field can be realized. In turn, field workers can utilize these technologies to expedite the decision-making process so that they may focus on meeting with clients and addressing agricultural watershed management issues. High-resolution (∼1.5 m postspacing) elevation data gathered by light detection and ranging (LiDAR) provides the topographic detail necessary to model hydrology at the field-scale (∼1 km2).

Non-artifactual surface depressions lead to erroneous surface flow patterns when using existing algorithms. So a sequential depression-filling algorithm (SDFA) has been developed to …

Systematic Analysis Of Drainage Events In Free Draining And Managed Subsurface Drainage Systems, Guy Bou Lahdou

Open Access Theses

Understanding the hydrologic controls that regulate outflow from free and managed subsurface drainage systems during drainage events can offer improved insight on the overall functioning and effectiveness of the systems so that they can be better managed or retrofitted to increase their environmental benefits. This study used drainage, precipitation, water table, and soil moisture data from a monitoring site located in east central Indiana to investigate the event hydrology of 22 drainage events in free and managed subsurface drainage systems. Relationships between event drainage volume, drain flow hydrograph metrics, column soil moisture, water table depth, and precipitation characteristics were explored …

A Survey Of Heavy Metals In Water, Soil And The Surrounding Plants In The Lower Rio Grande Valley, Erving W. Morelius

Theses and Dissertations - UTB/UTPA

Heavy metal pollution of the environment in recent years has become a major issue of importance for both human and environmental health. Samples were investigated for the potential pollution of the area as it is a vital produce producing area. During the study plant, soil and water samples were collected from the Donna Reservoir and Canal System to test the concentration of various heavy metals. The heavy metals tested included both potentially toxic and micronutrients in the samples which included arsenic, cadmium, chromium, copper, iron, lead, nickel and sulfur. During the study, a sixty day sampling period was used to …

Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability, Erin E. Scott

Graduate Theses and Dissertations

Anthropogenic enrichment of nitrogen and phosphorus is one of the most pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in quality are poorly understood. Laboratory microcosm studies were conducted to 1) quantify the response of litter C:P to a gradient of phosphorus (P) enrichment (0, 0.05, and 0.5 mg SRP/L) across leaf species with variable levels of degradability (sugar maple and oak), and 2) quantify the …

A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh

Graduate Theses and Dissertations

This study compares a novel simulation approach to the conventional Soil and Water Assessment Tool (SWAT) modeler's approach for targeting biofuel crop production on marginal lands. In conventional SWAT modeling approach, non-spatial definition of hydrological response units (HRUs) results in the simulation of biofuel crops on both marginal and non-marginal land. This study provides an alternative approach in which a marginal-land raster was integrated into the land use and land cover (LULC) raster in such a way that the land uses were divided into marginal and non-marginal components. This modified LULC was used for model setup which resulted in marginal …

Assessing The Impacts Of Surface Water Removal For Use In Natural Gas Extraction On A Watershed Level, Carrie Ann Davis

Graduate Theses and Dissertations

In this study, the Soil and Water Assessment Test (SWAT) was used as a tool to predict whether diffuse water removal from the Cadron Creek watershed for use with natural gas development would have an impact on downstream flow within the watershed. Cadron Creek watershed expands across four counties within Arkansas and is located in the Fayetteville Shale Gas region. This region is experiencing significant growth in natural gas development. Successful development of shale gas depends on the identification of what water supplies are available for production without interfering with community and environmental needs. The SWAT model used to evaluate …

Nutrient Dynamics In Stormwater Runoff From Green Roofs With Varying Substrate, John Michael Fohner

Graduate Theses and Dissertations

One major concern with urban development is the increasing amount of stormwater runoff from large expanses of impervious surfaces. These impervious surfaces reduce the ability of stormwater to infiltrate into the soil and eventually groundwater, which leads to greater amounts of surface runoff. Green technology serves as a viable solution to many of the environmental problems presented by modern development. Fifteen mock, extensive green roofs were built in the fall of 2008 at the Watershed Research and Education Center in Fayetteville, Arkansas. The goals of this project were to (1) measure the amount of stormwater runoff from varying treatments and …

Role Of Vegetation And Environmental Characteristics On Slope Stability In Northwest Arkansas, Michael Maguigan

Graduate Theses and Dissertations

Slope failure continues to pose risks to society because knowledge of environmental factors and their interactions are unclear and possibly misunderstood. This misunderstanding leads to generalizations about slope failure susceptibility mapping, despite knowing that slope failures are likely the result of an extensively complex set of interactions among a number of environmental, edaphic, and geomorphic characteristics. Therefore a series of experiments were conducted to investigate the effects of slope, soil texture, vegetation cover, bedrock permeability, and compaction,. A wooden flume with a slope face 1 m wide by 1.5 m long with a 10 cm toe was constructed to contain …

Geochemical Controls On Mercury Methylation In Backwaters Of A Gulf Coastal Plain River System, Implications For Water Column Processes, Liam N. Schenk

Graduate Theses and Dissertations

The abundance and distribution of mercury and methyl mercury were investigated at three sites in the lower Ouachita River in the summer of 2010 in an effort to provide the first characterization of the extent of mercury contamination in this river system, and to investigate the potential for mercury methylation in the water column of backwaters off of the main channel. Results showed that filtered methyl mercury was positively correlated to dissolved organic carbon (r2=0.76) for water samples taken from the bottom 1 ft of the water column at three sites, suggesting the importance of dissolved organic carbon in mercury …