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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
Sedimentary Record Of Extreme Events In The Lake Maurepas Basin, Southern Louisiana, Jonathan Edward Lambert
Sedimentary Record Of Extreme Events In The Lake Maurepas Basin, Southern Louisiana, Jonathan Edward Lambert
Honors Theses
No abstract provided.
Assessment Of Habitat Quality For Red Snapper, Lutjanus Campechanus, In The Northwestern Gulf Of Mexico: Natural Vs. Artificial Reefs, Brittany Dawn Schwartzkopf
Assessment Of Habitat Quality For Red Snapper, Lutjanus Campechanus, In The Northwestern Gulf Of Mexico: Natural Vs. Artificial Reefs, Brittany Dawn Schwartzkopf
LSU Master's Theses
Habitat quality of natural and artificial reefs for red snapper (Lutjanus campechanus) in the northwestern Gulf of Mexico (Gulf) is important as this area is home to the majority of the Gulf’s artificial reef system, in the form of oil and gas platforms, in addition to the largest extent of high vertical relief natural habitat. This study sought to assess habitat quality of natural reefs of varying habitat complexity and an artificial reef complex located on the LA continental shelf. Habitat quality was assessed by comparing red snapper diets and foraging patterns, and nutritional condition using the liver-somatic index (LSI) …
Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga
Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga
LSU Doctoral Dissertations
Soft-sediment benthic environments are amongst the largest marine ecosystems in the world and play important roles in many ecosystem functions. In recent years, exploitation of resources and unintentional impacts on deep-sea benthic environments has increased. The Deepwater Horizon oil spill of 2010 in the northern Gulf of Mexico (GoM) represented a prime example of this. The oil spill not only highlighted deficiencies of data and information on baseline conditions, but also represented an opportunity to learn more and develop better methods for the future. Deep-sea imaging platforms such as autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) have been …
Holocene Paleoenvironmental Reconstruction From Mexico's Pacific Coast-A Paleotempestological Investigation, Thomas Bianchette
Holocene Paleoenvironmental Reconstruction From Mexico's Pacific Coast-A Paleotempestological Investigation, Thomas Bianchette
LSU Doctoral Dissertations
This dissertation examines the paleoenvironments of four lagoons from Mexico’s Pacific coast, with the aim of retrieving sediment deposition from storm surge events to determine long-term tropical cyclone (TC) records. Lagoons Agua Dulce, Boquita, Mitla, and Nuxco are located along a 700 km stretch in states Jalisco and Guerrero. Roughly 70 meters of sediment were collected and subjected to multiple proxies, including loss-on ignition, a microfossil survey, and geochemical analysis. Nuxco’s dynamism is caused by intense and prolonged rainfall (largely from TCs), responsible for increasing water level, opening the tidal inlet, and draining the site (termed “blowouts”). High amounts of …
Phytoplankton Response To South Louisiana Crude Oil Exposure: Determining Impacts At Individual, Community, Toxin Production, Enzymatic-Activity And Gene-Expression Levels, Koray Ozhan
LSU Doctoral Dissertations
The Deepwater Horizon oil spill in the Gulf of Mexico (GoM) raised an important question. What is the ecological impact of the oil, the dispersant, and the dispersed oil to the GoM ecosystem? Significant and varying research efforts have contributed answers to this question. However, to better understand the complete ecological consequences of the spill in the GoM, the impact of the spill at the base of marine food web should be examined. This research aims to understand impact of the spilled oil, South Louisiana crude oil (LSC), the chemical dispersant, Corexit® EC9500A, and the dispersed oil on phytoplankton communities …
Temporal Variability Of Particulate Organic Carbon Fluxes In The Northern Gulf Of Mexico, Somiddho Bosu
Temporal Variability Of Particulate Organic Carbon Fluxes In The Northern Gulf Of Mexico, Somiddho Bosu
LSU Master's Theses
There is limited data of Particulate Organic Carbon (POC) export from the Northern Gulf of Mexico and this work presents the first estimation of the efficiency of the “biological pump” in this region. In oligotrophic oceans like the Gulf of Mexico, POC is the main source of particles and POC flux is the key mechanism for the removal of particle reactive contaminants and pollutants from upper ocean water column. Particle-reactive, the naturally occurring radionuclides are useful tracers of the sinking flux of organic matter from the surface to the deep ocean. The disequilibrium between natural radioisotope pair 238U-234Th as well …
Legacy Phosphorus Implications In The Lake Pontchartrain Estuary Sediment Due To The 2011 Bonnet Carre Spillway Opening, Nhan Thanh Nguyen
Legacy Phosphorus Implications In The Lake Pontchartrain Estuary Sediment Due To The 2011 Bonnet Carre Spillway Opening, Nhan Thanh Nguyen
LSU Master's Theses
Phosphorus (P) is an essential nutrient for life and excess P in aquatic systems can trigger algal blooms. Nutrient-rich Mississippi River water is diverted into the Lake Pontchartrain estuary (LPE) periodically through the Bonnet Carré Spillway (BCS) to avoid downstream flooding to the city of New Orleans, Louisiana and can significantly increase the internal P load in the sediment. A sequential P fractionation procedure was performed on sediments collected before the opening and after the closing of the 2011 BCS operation to understand the role of these large river diversions on P dynamics. Before the 2011 BCS opening, 10,368 Mt …
Does Reproductive Potential Of Red Snapper In The Northern Gulf Of Mexico Differ Among Natural And Artificial Habitats?, Hilary Day Glenn
Does Reproductive Potential Of Red Snapper In The Northern Gulf Of Mexico Differ Among Natural And Artificial Habitats?, Hilary Day Glenn
LSU Master's Theses
This study compares the reproductive potential of red snapper (Lutjanus campechanus) at artificial and natural habitats. Natural habitats are areas of vertical relief created from biogenic/geologic processes that are thought to be the historical centers of abundance for red snapper in the northern Gulf of Mexico. Red snapper were collected from 2011 to 2013 at three natural habitat sites and two artificial habitat oil and gas platform sites. The mean gonadosomatic indices (GSI), maturity at size and age, spawning indicators, batch fecundity, spawning frequency, and annual fecundity for red snapper at each habitat were analyzed to examine reproductive potential among …
Polonium-210 Dynamics In The Northern Gulf Of Mexico, Patrick Robert Jones
Polonium-210 Dynamics In The Northern Gulf Of Mexico, Patrick Robert Jones
LSU Master's Theses
Polonium-210 (t1/2=138 d) is the most common among the 33 known radioisotopes of Polonium found in the natural environment. It is produced by the radioactive decay of its long-lived grandparent Lead-210(t1/2=22.3 d) via Bismuth-210 (t1/2=5.012 d) and forms as part of the natural Uranium-238 decay series. The primary hazard associated with Polonium-210 is its radioactivity, as an alpha particle emitter. Marine organisms receive their maximum radioactive dose in the natural environment from Polonium-210. Polonium has been known to bioaccumulate in the marine food web and can be potentially harmful to humans via the intake of certain marine organisms. Thus it …
Cdom Optical Properties Near Dwh Site, Gulf Of Mexico: Pot Oil Spill, Zhi Li
Cdom Optical Properties Near Dwh Site, Gulf Of Mexico: Pot Oil Spill, Zhi Li
LSU Master's Theses
The Deep Water Horizon (DWH) oil spill resulted in the largest accidental release of crude oil in U.S. waters with both short- and long-term effects on the marine environment. Extensive studies conducted immediately following the oil spill in the northern Gulf of Mexico provided greater understanding of the physical processes influencing the distribution of the released oil, including the use of optical detection of polycyclic aromatic hydrocarbons (PAHs), a toxic crude oil fraction in the northern Gulf of Mexico. In this study, the optical properties of chromophoric dissolved organic matter (CDOM) and the concentrations of dissolved organic carbon (DOC) were …
Numerical Experiments Of Hurricane Impact On Vertical Mixing And De-Stratification Of The Louisiana Shelf Waters, Mohammadnabi Allahdadi
Numerical Experiments Of Hurricane Impact On Vertical Mixing And De-Stratification Of The Louisiana Shelf Waters, Mohammadnabi Allahdadi
LSU Doctoral Dissertations
The numerical model FVCOM (Finite Volume Community Ocean Model) was applied to study the effects of Hurricane Katrina on the vertical mixing over the Louisiana shelf and the process of post-storm re-stratification. Wind field from Hurricane Katrina was generated using a single vortex analytical model and was evaluated using available wind measurements over the shelf. Simulations of shelf circulation under Hurricane Katrina were done through several numerical tests to find the best approach for treating vertical eddy viscosity. Model results for the shelf during Katrina demonstrated opposite currents between surface and bottom for most of the shelf area. Results also …
Effect Of The Bp Deepwater Horizon Oil Spill On Critical Marsh Soil Microbial Functions, Jason Paul Pietroski
Effect Of The Bp Deepwater Horizon Oil Spill On Critical Marsh Soil Microbial Functions, Jason Paul Pietroski
LSU Master's Theses
On April 20, 2010, the BP Deepwater Horizon (DWH) offshore oil platform exploded releasing ~ 795 million L of southern Louisiana (LA) light sweet crude oil into the Gulf of Mexico. Approximately 7.9 million liters of dispersant, Corexit EC9500A, were applied for remediation. The effect of BP DWH crude oil and Corexit EC9500A on two marsh soil microbial processes, (mineralizable nitrogen and denitrification), were examined in the laboratory. Surface soil samples were collected from an unimpacted salt marsh site proximal to areas that suffered light to heavily oiling in Barataria Bay, LA. Additions of oil were at a ratio of …
Cyanobacteria Harmful Algal Blooms In South Louisiana Estuaries : A Synthesis Of Field Research, Management Implications, And Outreach, Emily Anne Smith
Cyanobacteria Harmful Algal Blooms In South Louisiana Estuaries : A Synthesis Of Field Research, Management Implications, And Outreach, Emily Anne Smith
LSU Doctoral Dissertations
Estuaries are biologically productive and important habitats for several fisheries. However, human intervention has separated many estuaries from their needed freshwater source and the commonly used solution is to use diversions to regulate the flow. This episodic increase in nutrients into estuaries has sometimes led to the formation of freshwater cyanobacteria HABs (CyanoHABs). The goal of this dissertation was to look at a field research study of phytoplankton bloom dynamics; management implications for cyanobacteria entering estuaries; and an outreach effort in relation to residents knowledge about cyanobacteria and algae. The first study compared the phytoplankton bloom dynamics, specifically CyanoHABs, in …
Effects Of Storm Surge And Nutrient Loading On Coastal Wetland Soil Processes: Implications For Ecosystem Function, Morgan Mckee
Effects Of Storm Surge And Nutrient Loading On Coastal Wetland Soil Processes: Implications For Ecosystem Function, Morgan Mckee
LSU Master's Theses
Coastal Louisiana is at risk from increases in salinity from storm surge and nutrient loading from the Mississippi River. Increased salinity causes plant death, decreases in microbial productivity, and shifts in biogeochemical processes. Eutrophication is linked to shifts in plant communities and changes in wetland biogeochemical properties. We hypothesized that 1) storm surge would increase soil porewater salinity and decrease extractable ammonium (NH4), and 2) long-term nutrient loading would decrease soil extracellular enzyme activity and increase total nutrients. Intact soil cores from two sites in the Wax Lake Delta were continually flooded with 35 g L-1 salt water for 1, …
Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis
Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis
LSU Doctoral Dissertations
Saltmarsh loss is occurring at high rates in Louisiana (LA), but understanding the impacts that marsh degradation has had on historical abundance of estuarine nekton in Barataria Bay, LA is lacking. I first examined the differences between fishery independent and fishery dependent data as indices of relative abundance. Previous studies used landings data to evaluate the importance of marsh habitat (e.g. distance of marsh edge and area of intertidal marsh) to fisheries production, but for most species, landings and survey data showed differing patterns of abundance through time. These findings emphasize the importance of using survey data (not landings data) …
Nutrient And Sediment Effects On Oligohaline Marsh Plant Community In Mississippi River Delta, Sareh Poormahdi
Nutrient And Sediment Effects On Oligohaline Marsh Plant Community In Mississippi River Delta, Sareh Poormahdi
LSU Master's Theses
The Mississippi River Delta comprises approximately 40% of the coastal wetlands in the conterminous United States, but has experienced more than 80% of the wetland loss in part due to flood control levees that have hydrologically isolated the lower River from the adjacent wetlands for a century. Thus, reconnecting the River to the wetlands through diversions is one of the approaches being used to reduce the rate of wetland loss. However, the diversion structures were originally designed to deliver freshwater rather than sediment. Furthermore, nutrient concentrations in the River water have increased during the past half-century as a result of …
Failed Agricultural Impoundments: An Interdisciplinary Assessment Of Community Structure And Social Resilience, Stacy Nicole Peterson
Failed Agricultural Impoundments: An Interdisciplinary Assessment Of Community Structure And Social Resilience, Stacy Nicole Peterson
LSU Master's Theses
The remnants of the wetland reclamation era of the early 1900s are visible in the leveed, drained, and failed impoundments across the United States, and especially in coastal regions. The common themes of their history are flooding, restoration, and – sometimes - community resilience. The physical changes occurring during and after impoundment, and after failure includes subsidence, erosion, and flooding are well-documented. Here I construct an environmental history that integrates data on these physical changes with archival records, historical documents, site visits and personal interviews. The primary region of focus is ‘Delta Farms’ - a failed agricultural impoundment in Lafourche …
Hurricane-Induced Geologic Change And Palynological Assessment Of A Rapidly Subsiding Deltaic Environment In Coastal Louisiana, James Dustin Naquin
Hurricane-Induced Geologic Change And Palynological Assessment Of A Rapidly Subsiding Deltaic Environment In Coastal Louisiana, James Dustin Naquin
LSU Master's Theses
This study is focused on a paleoenvironmental history of a backbarrier coastal lagoon situated on the seaward margin of the Lafourche delta lobe in coastal Louisiana. A 2.2 meter long sediment core (Core BC 53) was collected from a mangrove-covered land strip on the northern margin of Bay Champagne, and was studied using pollen analysis, Loss-on-ignition (LOI), X-ray Fluorescence (XRF) analysis, and Cesium-137 and radiocarbon dating techniques to establish sediment stratigraphy and core chronology. Bay Champagne, a backbarrier lagoon formed during the evolution of Bayou Lafourche, has shown to be highly sensitive to geomorphological and vegetation changes induced by sea-level …