Digital Commons Network^™

Effect Of Sex On The Accumulation Of Hepatic Mercury In Mallards Wintering In Louisiana, Latorya E. Mason

Master's Theses

The increase in mercury production through anthropogenic activities has led to a global crisis of mercury pollution that poses a significant threat to the health of both humans and wildlife. Aquatic ecosystems are especially at risk due to the creation of methylmercury, a toxic form of mercury, by sulfate-reducing bacteria in anoxic sediments and soils. Methylmercury enters the food chain where it bioaccumulates in individual organisms and then biomagnified with increasing trophic level. Aquatic birds are useful bioindicators of many pollutants, including mercury, due to their abundance and position in the food chain. Previous studies have primarily focused on mercury …

Molecular Identification Of Oomycete Species Associated With Woody Plants In Louisiana And Survey Of Oomycete Species Associated With Live Oak Trees Planted On The Louisiana State University Campus, Hamilton Crockett

LSU Master's Theses

Three Oomycetes genera, Phytophthora, Phytopythium and Pythium, contain many important plant pathogens. Historically, Phytophthora infestans, responsible for the great Irish potato famine, and Phytophthora ramorum, causal agent of sudden oak death disease, are the two better-known high impact pathogens. The LSU AgCenter Plant Diagnostic Center (PDC) has been isolating putative Phytophthora and related species from combined root and soil samples collected from various woody ornamentals and trees for over a decade. In August of 2016, Louisiana received torrential rains, which resulted in historic flooding in several southern parishes. During subsequent years, the PDC staff isolated a …

Aphid Herbivory On Industrial Hemp, Cannabis Sativa L., And The Impact Of Plant-Soil Feedbacks On Hemp Performance In Louisiana, Alex Leede

LSU Master's Theses

Industrial hemp, Cannabis sativa L., is defined as having less than 0.3% delta-9-tetrahydrocannabinol by dry weight. It can be grown for fiber, food, oil, and cannabinoids. As a newly legalized crop, little research exists regarding the cultivation or pest management practices in Louisiana. The versatility of industrial hemp may allow for substantial future production in Louisiana. This project set out to understand the impact of previous crops on hemp performance and soil microbial communities. Soybean, Glycine max L. (Merr), grain sorghum, Sorghum bicolor (L.) Moench, and sweetpotato, Ipomeae batatas (L.) Lam, were selected as soil conditioning crops because they are …

The Race To Fifty Feet: An Effort To Determine The Benefits Of Deepening The Mississippi River, Brian Miles

University of New Orleans Theses and Dissertations

This research examined the benefits and drawbacks of deepening the Lower Mississippi River to fifty feet. It established that the deepening of the Lower Mississippi River will impact not only the local area but also the inland regions that rely on the river systems and lower river ports for product movement. The perspectives of vessel operators, maritime industry experts and charterers are provided to offer insight. The sources for the research include educational literature, maritime research and interviews of industry experts. Based on this research, it is clear that this project will benefit many parties. The beneficiaries will include both …

Investigating Local Adaptation To Hypoxia Stress In The Eastern Oyster Through Comparative Transcriptomics, Heather Nichole Smith

LSU Master's Theses

Climate change represents one of the most important challenges to biodiversity, therefore it is important to understand the mechanisms that allow species to respond to rapid environmental change. Here, we compared two populations of eastern oysters, Crassostrea virginica, from the Gulf of Mexico to study the mechanisms underlying hypoxia tolerance. Using a common garden experiment and comparative transcriptomics, we identified sets of genes involved in the hypoxia response and found differences in both the timing and baseline expression of hypoxia-responsive genes between tolerant and sensitive populations, consistent with a scenario of local adaptation. These genes include the signaling transcription factor …

Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam

LSU Master's Theses

Eastern oysters (Crassostrea virginica) provide valuable ecosystem services and support a productive commercial industry in the northern Gulf of Mexico. Declining abundance from water quality changes and other factors drives development of management and restoration strategies focused on a comprehensive, metapopulation approach. Identifying oyster resource zones based on water quality combined with selective breeding of oysters adapted to specific conditions provides strategies to support aquaculture development and ensure resilient oyster populations and high production. Using 2015-2019 satellite-derived continuous salinity and temperature data for coastal Louisiana, this work created maps defining oyster resource zones supportive of (1) broodstock sanctuary …

Examining The Sustainability Of Restored Sub-Tidal Oyster Reefs In Coastal Louisiana, Sarah C. Leblanc

LSU Master's Theses

Climate related alterations and anthropogenic disturbance threaten the ecological integrity and sustainability of coastal estuaries. Many activities seek to restore and sustain these at-risk areas with the goal of restoring systems to historic patterns of succession and community development; however long-term monitoring of restoration projects remains limited. Additionally, restoration efforts aim to achieve certain success thresholds, however, these thresholds are often vague, absent, or inconsistent, and receive little long-term analyses following restoration. A key coastal engineer, the eastern oyster (Crassostrea virginica), provides multiple ecosystem services, but recent population decline has prompted investment in restoration. Restoration activities include cultch …

Evaluation Of Food Safety Practices At Louisiana Summer Feeding Sites And Food Safety Communication Via Social Media During Crises, Peyton E. Haynes

LSU Master's Theses

The United States Department of Agriculture’s Summer Food Service Program (SFSP) provided children under the age of 18 in low-income areas 145 million free meals in 2018 through summer feeding sites. Food safety issues arise for Louisiana feeding sites due to time-temperature controlled foods served, weather patterns in Louisiana, seasonal staff and short operation time, and lack of equipment. The purpose of this study was to assess food safety practices at Louisiana feeding sites through observational study with intention to compare food practices at institutional and noninstitutional sites. A rubric following USDA food safety guidelines based on categories: hot holding, …

Isolation And Characterization Of Bacteria In A Toluene-Producing Enrichment Culture Derived From Contaminated Groundwater At A Louisiana Superfund Site, Madison Mikes

LSU Master's Theses

In an effort to better understand the role that various microbes may play in toluene production, bacteria from a toluene-producing enrichment culture derived from contaminated groundwater at a Superfund site were cultivated and isolated on low nutrient solid media. A total of 14 solid medium formulations containing varying pH ranges, carbon sources, solidifying agents, and incubation gas headspaces were used to obtain 278 isolates in pure culture. Isolated bacteria, identified using partial 16S rRNA gene sequences, were most closely related with the genera Anoxybacillus, Azospira, Bacillus, Bradyrhizobium, Cellulosimicrobium, Micrococcus, and Propionicimonas.

Further attempts …

The Collection Of Baseline Data On Insect And Plant Communities Across Multiple Salinity Zones Within Louisiana's Tidal Marshes, Benjamin G. Aker

LSU Master's Theses

Tidally influenced coastal marshes provide numerous important ecosystem services, but these habitats are experiencing extreme habitat loss. Louisiana’s coastal marshes in particular are vulnerable to land loss resulting from both anthropogenic and natural causes, but especially to subsidence and relative sea-level rise. In response, the Louisiana Coastal Restoration and Protection Authority has outlined and is currently implementing the largest ever attempt at habitat restoration. A major component of this habitat restoration attempt is the use of freshwater and sediment diversions to increase the input of low salinity water, sediment, and nutrients needed to slow marsh loss and build land. Coastal …

Ecological Analyses Of Macroinvertebrates And Fish Species In Six Streams On A Louisiana Military Base From 2001 To 2019, Danielle Joerger

Biology Theses

An in-depth ecological analysis of how and why the aquatic community changes over time was conducted for 6 streams on the Fort Polk military base in Louisiana using data collected from 2001 to 2019. Fort Polk is a unique location as nineteen first-order streams are located on the premises belonging to three separate drainages. The primary goal was to determine whether temporal or between-drainage variation has a larger effect on community structure. To accomplish this the effects of disturbance on fish and macroinvertebrate assemblages was determined temporally and between drainages. Several hypotheses were drawn from this: 1) temporally, assemblages exhibit …

Intrusive Advising And Retention Practices In A College Of Agriculture: A Case Study Of First-Year Student Experiences, Amanda Martin

LSU Doctoral Dissertations

The purpose of this qualitative case study was to explore the perceptions of first-year students who experienced intrusive advising and retention initiatives in the College of Agriculture at Louisiana State University (LSU). Research participants consisted of 20 first-year students enrolled in the college in the fall of 2018. One-on-one, face-to-face interviews with first-year students were conducted to gain insight and understand student experiences with intrusive advising and retention initiatives within the College of Agriculture. College student retention and factors that contribute to understanding retention have been extensively studied (Astin, 1993; Braxton, Hirschy, & McClendon, 2004; Habley, Bloom, & Robbins, 2012; …

Agricultural Education Teachers' Perceptions And Use Of Environmental Education In Louisiana Schools, Olivia M. Soler

LSU Master's Theses

The purpose of this study was to describe the status of environmental education (EE) in Louisiana high school agriculture classrooms. A census of Louisiana Agriscience Teacher Association (LATA) members was conducted to understand their perceptions, attitudes, and barriers regarding EE implementation. Icek Ajzen’s Theory of Planned Behavior was utilized as the theoretical framework. Data were collected through an online survey research method and analyzed using descriptive statistics. Results suggest that most LATA members incorporate EE into their curriculum relatively sparingly, perceive EE to be beneficial for students, and are in need of funding to incorporate EE into their curriculum as …

Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger

University of New Orleans Theses and Dissertations

Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased …

Exploring Alternative Giant Salvinia (Salvinia Molesta D.S. Mitchell) Management Strategies, Bradley T. Sartain

LSU Doctoral Dissertations

Dense infestations of the free-floating aquatic fern giant salvinia (Salvinia molesta D.S. Mitchell) have been expanding across the southeastern United States for over two decades. Although herbicide programs have provided relief to giant salvinia infested areas, morphology and growth characteristics make management difficult. A series of mesocosm trials were conducted to explore alternative management strategies for giant salvinia. Evaluation of non-registered aquatic herbicides showed that rates of sulfometuron and metsulfuron controlled giant salvinia and provided a 98 to 100% biomass reduction. An outdoor mesocosm trial evaluated potential glyphosate resistance in giant salvinia in select water bodies throughout Louisiana. Differences …

Evaluation Of Growth Characteristics, Yield, Marketability And Nitrate Levels Of Lettuce (Lactuca Sativa L) Cultivars Produced In South Louisiana, William D. Afton

LSU Master's Theses

Lettuce (Lactuca sativa L.) is an important leafy vegetable crop grown in worldwide food systems with the United States ranking second behind China in total production. In 2009 the USDA Food Economic Research Service reported 1,057,715 hectares of lettuce grown in the world. Lettuce is a common market crop grown across the United States. Nitrate (NO^3-) accumulation in lettuce and other leafy vegetables has been found to be a potential health threat and when consumed by humans, potentially causing methaemoglobinaemia and other diseases. There are four main types of lettuce and numerous cultivars within each type. Fresh …

Patterns In Abundance Of Louisiana’S Avifauna Revealed By The Louisiana Bird Atlas Project, Matthew L. Brady

LSU Master's Theses

The Louisiana Bird Atlas Project is a multi-year citizen science effort designed to quantify bird distribution and abundance for all species regularly occurring in the state of Louisiana during two time periods: summer and winter. Data were collected by volunteers in a citizen science framework across eight years, from 2007 to 2014. A total of 351 species was recorded (254 during the Summer Bird Atlas and 315 during the Winter Bird Atlas). Maps showing distribution and relative abundance for each species were generated within a Geographical Information System, and were accompanied by short descriptions of status, distribution, abundance, and other …

Impact Of Pre-Bloom Square Loss On Yield And Lint Quality In Louisiana Cotton Cropping Systems, Cory L. Cole

LSU Master's Theses

During the 2016 growing season, research was conducted at three locations in the state of Louisiana to evaluate the impact of pre-bloom square loss on cotton lint yield and fiber quality. Two cotton varieties, Phytogen 499 WRF and Phytogen 222 WRF were chosen up which to imitate early season square loss due to tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) and/or cotton fleahopper, Pseudatomoscelis seriatus (Reuter) feeding or unfavorable weather conditions. Thirty plants within each plot were selected and squares were counted. Squares were assigned numbers, and numbers were then randomized using a computerized number generator. To simulate intervals …

Influence Of Environmental Conditions And Inundation History On Bacterial Diversity Of Salt Marsh Soils In Southern Louisiana, Brandon M. Bagley

Masters Theses

Diversity patterns and controls on bacterial community composition were investigated from coastal salt marsh soils in southern Louisiana (USA) from 2012 – 2014. These salt marshes are part of an extensive coastal landscape that is experiencing land loss due to subsidence, sea-level rise, and anthropogenic activities, including from the impacts of the Deepwater Horizon oil spill in 2010. Prior to the oil spill, microbiology research focused predominately on biogeochemical roles and not on taxonomic representation in the soils or on understanding the significance of taxonomic diversity at the microbial level to marsh food webs or ecosystem dynamics. The purpose of …

Microbial Ecology Of Waterborne Pathogens In Sus Scofra And Odocoileus Virginianus In The Jackson Bienville Wildlife Management Area, Jaymes Hunter Collins

Doctoral Dissertations

Previous studies have demonstrated that feral swine (Sus scofra ) are significant reservoirs for a number of pathogens that present a potential threat to wildlife and humans. Despite this, few studies have gone beyond quantifying the incidence of these pathogens to further probe their ecology within a specific habitat or ecosystem.

Overall, the objective of this study was to characterize three potential reservoirs in a feral swine infested habitat; two ungulates, and one aquatic reservoir. Our study area was the Jackson-Bienville Wildlife Management Area (J-B WMA). We chose four waterborne bacteria: Brucella spp., Leptospira interrogans, Salmonella enterica, and Helicobacter …

Ant Diversity And Community Structure In Coastal Dunes And Wetlands, Xuan Chen

LSU Doctoral Dissertations

How do many species live in a certain place? How does species composition changes among habitats? And what mechanisms decide species distribution? These are fundamental questions in community ecology. I first investigated ant diversity in two coastal ecosystems (dunes and wetlands) in the northern Gulf of Mexico, and then used the distribution patterns to infer assembly processes that structure ant communities in coastal areas. Specifically, the following hypotheses are tested: (1) coastal systems support lower ant diversity due to the unsuitable environment; (2) species living near the seashore are a subset of those exist near inland; (3) deterministic processes are …

Pathogenic Enteric Viruses In Louisiana Oysters And Environmental Waters, Naim Montazeri Djouybari

LSU Doctoral Dissertations

Norovirus (NoV) and pathogenic enteroviruses are the major causes of gastroenteritis in humans worldwide, and are usually transmitted through direct or indirect exposure to raw or partially treated sewage. Filter-feeding shellfish concentrate virus particles from the water and transmit them to humans. The occurrence of norovirus GI and GII and fecal indicators in Louisiana eastern oysters (Crassostrea virginica) and harvest water were investigated on a biweekly basis for almost one year. Only one oyster sample was positive for NoV GII at 3.5 log10 genomic copies/g digestive tissues. A stool specimen obtained from an infected individual associated with a norovirus outbreak …

Population Dynamics And Genetic Structure Of Louisiana Black Bears In The Lower Mississippi Alluvial Valley Of Louisiana, Jared Scott Laufenberg

Doctoral Dissertations

In 1992, the U.S. Fish and Wildlife Service granted the Louisiana black bear threatened status under the U.S. Endangered Species Act, listing loss and fragmentation of habitat as the primary threats. The 1995 Recovery Plan outlines recovery goals designed to meet the objective of reducing threats to the Louisiana black bear metapopulation and supporting habitat. To meet that objective, the Recovery Plan requires 1) at least 2 viable subpopulations, 1 each in the Tensas and Atchafalaya River Basins, 2) movement corridors between the 2 viable subpopulations, and 3) long-term protection of the habitat supporting each viable subpopulation and interconnecting corridors …

Analysis Of The Mineral Composition Of Louisiana Wild Caught Shrimp By Icp-Oes And Classification Of Geographical Origin, Samantha Nichole Stein

LSU Master's Theses

Nationwide, seafood consumers are paying close attention to their seafood options and demanding transparency on point of origin. Recent studies have shown that shrimp can reflect the mineral content of the waters from which they are harvested. Mineral analysis was conducted using inductively coupled plasma optical emission spectrometry on the tail muscle from each coastal group and imported farmed raised samples. Analysis of variance was used to detect differences among catch locations and seasons along the Louisiana coast, as well as differences in the mineral profile of farm raised imported shrimp. Multivariate analysis of variance and descriptive analysis was used …

Effects Of Iron On Cercospora Leaf Blight Of Soybean, Eduardo Chagas Ferreira Da Silva

LSU Master's Theses

Cercospora leaf blight (CLB) of soybean caused by Cercospora kikuchii is an important disease in Lousiana. Preliminary screening of foliar applications of the micronutrients Fe, Mn, Cu, Zn, B, Mo and Al, showed that Fe decreased CLB severity consistently. The objective of this work was to test the effects of commercial formulations of Fe, Manny Plex Fe and Fe EDTA (Brandt Consolidated, Springfield, IL) on leaf colonization by C. kikuchii, symptom development (blight and purple leaves), and yield. Four rates of Manny Plex Fe and four rates of Fe EDTA were applied to field plots at R5 growth stage. Leaf …

Population Dynamics Of The Louisiana Black Bear In The Upper Atchafalaya River Basin, Kaitlin Christine O'Connell

Masters Theses

The Louisiana black bear (Ursus americanus luteolus) is listed as Threatened under the Endangered Species Act as a result of habitat loss and human-related mortality. Two of the 3 sub-populations must be viable for delisting to occur. I collected hair samples from 2010 to 2012 in a DNA mark-recapture study to augment data collected from 2007 to 2009 in the Upper Atchafalaya River Basin (UARB) to estimate abundance (N), growth rate (λ), and apparent survival rates (φ) to ultimately be used in a population viability analysis. In addition, I evaluated the effects of the opening of the …

Development Of Integrated Pest Management For Sugarcane Borer, Diatraea Saccharalis In Rice, Jaspreet Kaur Sidhu

LSU Doctoral Dissertations

Rice is grown over an area of approximately 500,000 acres in Louisiana. The lepidopteran stem borer complex attacking rice in the southern U.S includes stalk borer Chilo plejadellus Zincken, sugarcane borer (SCB) Diatraea saccharalis (F.) and Mexican rice borer, Eoreuma loftini Dyar. With the increasing impact of stem borers in Louisiana, an urgent need exists to develop strategies for management. Currently, no IPM program is in place for stem borers in Louisiana rice and research has been initiated to develop an IPM program for these pests. The first objective of this research was focused on host plant resistance. For this …

Quantifying Rates Of Autocompaction In The Pearl River Marsh, Louisiana, Jeremiah Nicholas Prouhet

Master's Theses

Annual rates of shallow autocompaction (< 1 m) were calculated in the upper ~one meter of sediment from six cores of a transect in the Pearl River Marsh (PRM), Louisiana, in order to determine the most significant sedimentary property controlling this process. Compaction-free wedge cores were sub-sampled at one centimeter intervals to collect the following data: age control, using 137Cs and 210Pb, and sedimentary variables, specifically, particulate organic carbon, bulk density, median grain size, porosity, and water content. An upper and an underlying sedimentary unit (named the 137Cs and 210Pb units) were defined between radiometric datum levels, and their sedimentary properties were statistically tested for significant differences using the non-parametric Mann-Whitney test. Rates of autocompaction were calculated from the model of Williams (2003), and both rates of autocompaction and sedimentation were tested for significant differences between the upper and lower sedimentary units.

The upper unit in the six cores generally had lower bulk density, higher water content, higher porosity, and higher particulate organic carbon than the underlying unit, but with some interesting exceptions. Additionally, annual autocompaction and sedimentation rates were greatest in the overlying unit at stations PR02 (0.39 ± 0.05 cm/y) and PR05 (0.42 ± 0.03 cm/y) and greatest in the underlying unit at stations PR02 (0.22 ± 0.08 cm/y) and PR03 (0.18 ± 0.06 cm/y). Based on Spearman correlations, rates of autocompaction were most strongly correlated to and influenced by rates of sedimentation rather …

Characterization Of The Subcortical Interactions Between Larvae Of The Southern Pine Sawyer Monochamus Titillator (F.) And The Larvae Of The Southern Pine Beetle Guild Using Molecular Gut Analyses, Erich N. Schoeller

LSU Master's Theses

The southern pine beetle guild (Coleoptera: Curculionidae: Scolytinae) is arguably the most destructive group of forest pests in the Southeastern United States. Laboratory assays suggest that larvae of wood borer associates from the genus Monochamus (Coleoptera: Cerambycidae) may be facultative intraguild predators of southern pine beetle guild. In this study the dynamics of the subcortical interactions between M. titillator (F.) and members of the southern pine beetle guild were examined using PCR-based molecular gut content analyses. Species-specific PCR primer sets were developed to work under multiplex PCR conditions to detect DNA of members of southern pine beetle guild in the …

Stochastic Trends In Crop Yield Density Estimation, David I. Maradiaga

LSU Master's Theses

The search for improved methods of estimating crop yield density functions has been a theme of recurrent research interest in agricultural economics. Crop yield density functions are the statistical instrument that generates probability estimates of yield risk, and risk is an important decision variable in production agriculture. Recent research in crop yield density estimation suggests that yield probability estimates can be sensitive to the way yield data are filtered, and if true, then the search for an “adequate filter” is warranted. Such a quest is pursued in this study. It is proposed that unit-root tests can be used to identify …