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Holocene Paleoenvironmental Reconstruction From Mexico's Pacific Coast-A Paleotempestological Investigation, Thomas Bianchette Jan 2014

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 …


Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis Jan 2014

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) …


Numerical Experiments Of Hurricane Impact On Vertical Mixing And De-Stratification Of The Louisiana Shelf Waters, Mohammadnabi Allahdadi Jan 2014

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 …


Cyanobacteria Harmful Algal Blooms In South Louisiana Estuaries : A Synthesis Of Field Research, Management Implications, And Outreach, Emily Anne Smith Jan 2014

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 …


Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga Jan 2014

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 …


Phytoplankton Response To South Louisiana Crude Oil Exposure: Determining Impacts At Individual, Community, Toxin Production, Enzymatic-Activity And Gene-Expression Levels, Koray Ozhan Jan 2014

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 …