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Louisiana State University

Articles 1 - 11 of 11

Full-Text Articles in Physical Sciences and Mathematics

Sediment Buffering And Recycling On An Annual To Centennial Scale Along The Mississippi River, Nikki E. Neubeck Apr 2022

Sediment Buffering And Recycling On An Annual To Centennial Scale Along The Mississippi River, Nikki E. Neubeck

LSU Master's Theses

Although the Mississippi River and its tributaries have been investigated for many years, the alteration of the river through dams, levees, and diversions has affected how sediment is transported from source to sink (>103 y). Previous provenance research using detrital zircon U-Pb dating indicates a slow transport time from source-to-sink, but recent anthropogenic alterations of the river may potentially diminish the transportation time of heavy minerals due to an increase in flow efficiency. The objective of this study is to analyze the degree of buffering and recycling of Mississippi River sediment over a range of short time scales, …

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Seasonal Transport Of Dissolved Inorganic Carbon And Total Alkalinity Across The Louisiana Shelf, Michelle M. Anderson Jun 2020

Seasonal Transport Of Dissolved Inorganic Carbon And Total Alkalinity Across The Louisiana Shelf, Michelle M. Anderson

LSU Master's Theses

Rivers and wetlands are a major source of terrestrial derived carbon for coastal ocean margins. Unfortunately, Louisiana’s wetlands are threatened by ongoing high rates of erosion, deterioration, and unprecedented rates of river water discharge that changes seasonally, leading to a net loss of terrestrial carbon into the northern Gulf of Mexico (nGOM). There exists a current lack of understanding about the distribution of dissolved inorganic carbon (DIC) and total alkalinity (TAlk) within the shallowest regions of the Louisiana shelf. Even less is known about how the transport of DIC alters seasonally with changes in river outflow and shelf currents. Quantifying …

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An Ecopath With Ecosim Analysis On Offshore Petroleum Platform Influences On Gulf Of Mexico Red Snapper, Valentin Gomez Apr 2020

An Ecopath With Ecosim Analysis On Offshore Petroleum Platform Influences On Gulf Of Mexico Red Snapper, Valentin Gomez

LSU Master's Theses

Offshore oil and gas platforms have had a significant presence in the Gulf of Mexico since the 1950s. An important secondary function of these structures is that they provide artificial habitat to fisheries, most notably Red snapper. Policy changes intended to reduce the risk associated with aging infrastructure have reduced the number of standing platforms from 4044 to 1867 from 2001 to 2018. The effect this loss of habitat has on Red snapper was tested by creating three scenarios of platform changes and modeling the perturbation from 2005 to 2050. The simulation was accomplished using the ecological model Ecopath with …

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Breaking Coastal Hypoxia: Destratification Of Gulf Of Mexico Deadzone To Encourage Oxygen Transport Downwards To Maintain Marine Fauna, Veda Thipparthi Nov 2019

Breaking Coastal Hypoxia: Destratification Of Gulf Of Mexico Deadzone To Encourage Oxygen Transport Downwards To Maintain Marine Fauna, Veda Thipparthi

LSU Master's Theses

As a consequence of seasonal eutrophication and human input, a vast hypoxic area termed The Dead Zone develops every year in the Gulf of Mexico (GOM) during summer along the Louisiana coastline characterized by vertical seawater density-stratification with oxygen concentrations less than 2 mg.l-1 at the seafloor. It poses a threat to bottom-dwelling faunae and their environment which has negative ecological and economic consequences. This project aims to mitigate hypoxia by employing mechanical impellers placed at strategic water depths and locations in the Gulf. Enhanced transport of oxygen results by mixing oxygen-enriched seawater at the surface, downward into the …

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Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall Jul 2019

Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall

LSU Master's Theses

Tidal marshes have been recognized for providing a number of important ecological services including soil carbon sequestration. However, the loss of tidal marsh habitat due to climate change and anthropogenic stressors exposes previously stored soil organic carbon (SOC) to oxidation. The vulnerability of SOC to oxidation depends on its chemical stability and environmental conditions limiting decomposition. Labile organic carbon (LC), decomposes quickly unless abiotic conditions limit decomposition. Recalcitrant organic carbon (RC) decomposes slower and is stored for longer time periods. Predicting long-term storage of SOC is complicated by the potential for multiple SOC sources, differences in chemical stability, and variation …

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Matrix Recharge In A Shrink-Swell Floodplain Forest Soil, Savannah R. Morales Jun 2019

Matrix Recharge In A Shrink-Swell Floodplain Forest Soil, Savannah R. Morales

LSU Master's Theses

Despite the global distribution of fine-grained Vertisols, the hydrology of these floodplain soils is still not well understood. Vertisols shrink and swell depending on soil moisture leading to a range of soil pore sizes, from large macropore cracks to smaller micropores, and consequently a range of hydraulic conductivities. Despite the plethora of research indicating the importance of both flooding and soil moisture in floodplain ecosystems, the specific role that flooding plays in soil moisture recharge has been less widely studied and remains of interest. Blue food dye and deuterated water were used as tracers to determine the role of the …

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Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo Mar 2019

Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo

LSU Doctoral Dissertations

The lower plain of the Mississippi River Delta contains approximately five coastal sedimentary basins that are topographically defined, and one shelf-crossing depocenter (the Birds Foot Delta). These depositional systems receive varying quantities of sediment from fluvial and marine sources and have rates of coastal land loss that are roughly inversely proportional to fluvial sediment supply. To combat land loss along these regions, Louisiana has launched a historic campaign to sustain and regrow coastal lands using, in part, river sediment diversions. Fine sediments constitute the majority of sediment load in the Mississippi River, but are under-studied with respect to dispersal processes, …

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Longitudinal Study Of The Attitudes And Behaviors Of Environmental Education Program Participants., Kasie R. Dugas Oct 2018

Longitudinal Study Of The Attitudes And Behaviors Of Environmental Education Program Participants., Kasie R. Dugas

LSU Master's Theses

The goal of this longitudinal study was to measure the attitudes and behaviors of participants of the Marsh Maneuvers program over the course of the last 25 years. The goal of the Marsh Maneuvers program is to educate students into becoming environmentally literate adults. Environmental literacy is considered herein to be people possessing knowledge about and positive attitudes and behaviors towards the environment. Although students learn basic science and environmental knowledge in the classroom, true environmental literacy is believed to require more hands-on understanding of the material. To evaluate the effectiveness of the program, the following three objectives were completed. …

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Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky Oct 2018

Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky

LSU Doctoral Dissertations

Pesticides used in the United States must undergo registration by the United States Environmental Protection Agency (USEPA), after a multitude of analyses ranging from environmental fate to aquatic toxicological impacts to human risk exposure. Testing varies for each chemical, some requiring more testing than others. In many cases, environmental factors are restricted in the analysis of chemical behavior and organismal testing is limited to larvae. Many pesticides are formulated to breakdown in the environment by means of photolysis, hydrolysis, or oxidation, either to ensure low-persistence, limited transport, or to form the active ingredient (pro-pesticides). Environmental influences on chemical behaviors include …

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Perils Of The Fungal Kingdom: Mycotoxins In Food And Feed, Adrianna Isobel Pribil Jul 2018

Perils Of The Fungal Kingdom: Mycotoxins In Food And Feed, Adrianna Isobel Pribil

LSU Master's Theses

Humans and fungi have a complex relationship, especially in regards to the many fungal secondary metabolites that can be produced. When secondary metabolites are toxic to animals and humans they are defined as mycotoxins. Fungi can grow on crops pre-harvest and post-harvest, and have the potential to produce mycotoxins which occur regularly in animal feed and food for human consumption. In high doses, mycotoxins cause variety of problems that result in economic losses and extreme health issues. However, multiple mycotoxins will co-occur in nature and commonly occur in low doses. Thus chronic low daily doses of multiple mycotoxins overtime may …

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Assessment Of Mercury Content In Louisiana's Freshwater Fish And Its Association To Se Concentrations, Alexander David Reyes-Avila Apr 2018

Assessment Of Mercury Content In Louisiana's Freshwater Fish And Its Association To Se Concentrations, Alexander David Reyes-Avila

LSU Master's Theses

Ample evidence has demonstrated the neurotoxic properties of organic Hg to humans. However, recent studies have proposed the protective effects of Se against organic Hg detected in marine fish. Louisiana’s freshwater bodies are exploited by recreational anglers that enjoy fishing as recreational activity and food source. Thus, testing of Hg in Louisiana was resumed in 2017 to update the state advisories. However, before drawing conclusions based solely on organic Hg, it might be useful to see how much Se is present in freshwater fish. The main objective of this study was to determine the Se:Hg molar ratio in Louisiana’s freshwater …

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