Physical Sciences and Mathematics Commons^™

Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Marine Cyanobacterium Synechococcus Sp. Ccmp 1334, Alyssa K. Sharbaugh

LSU Master's Theses

The marine cyanobacterium Synechococcus sp. CCMP 1334 was grown in a continuous culture system on a 12:12 h light:dark cycle at all combinations of low and high pCO2 (400 and 1000 ppmv, respectively), nitrate availability (nitrate-limited and nutrient-replete conditions), and temperatures of 21°C, 24°C, 28°C, 32°C, and 35°C. The maximum median nutrient-replete growth rate was ~1.15 d−1 at 32 –35°C. Median growth rates at 1000 ppmv pCO2 were higher than those at 400 ppmv at all temperatures, but most of the differences were statistically insignificant. Carbon:nitrogen ratios were independent of pCO2 at a fixed relative growth rate but decreased with …

Sensor Analytics For Subsea Pipeline And Cable Inspection: A Review, Connor R. Vincent

LSU Master's Theses

Submarine pipelines and cables are vital for transmitting physical and digital resources across bodies of water, necessitating regular inspection to assess maintenance needs. The safety of subsea pipelines and cables is paramount for sustaining industries such as telecommunications, power transmission, water supply, waste management, and oil and gas. Incidents like those involving the Nord Stream subsea pipeline and the SEA-ME-WE 4 subsea communications cable exemplify the severe economic and environmental consequences of damage to these critical infrastructures. Existing inspection methods often fail to meet accuracy requirements, emphasizing the need for advancements in inspection technologies. This comprehensive survey covers the sensors …

Translation Speed Influence On Tropical Cyclone Storm Tide And Surge Generation Along The Gulf Of Mexico Coast, Samantha L. Camarda

LSU Master's Theses

This research examines tropical cyclone translation speed as a factor in storm tide and surge height upon landfall on the United States Gulf Coast. Understanding the effect of translation speed on peak storm tide/surge height is needed to better prepare for and predict future damage from tropical cyclone events. Tropical cyclone data are taken from hourly interpolated best-track HURDAT2 data from 1970–2021. This study uses the HURDAT2 hourly interpolated observation data points (24-hours) pre-landfall to landfall. Translation speed is calculated based on the distance traversed between hourly points. Peak storm tide and storm surge data are taken from SURGEDAT from …

Atmospheric Impacts From The 2010 Deepwater Horizon Oil Spill, Charles Philip Johnson

LSU Master's Theses

Although the ecological devastations induced by an oil spill are well studied, the hydrometeorological impacts from a long-term slick have gone unnoticed. The ocean-surface alterations stemming from the lasting oil footprint increase solar radiation absorption which in turn alters the surface pressure and moisture gradients and wind speeds thereby influencing precipitation surrounding the oil spill. Revealing the potential impacts from these could better aid in the safety of crews cleaning spills and provide a better understanding of how humans alter the landscape. This thesis examines the changes in local hydrometeorology brought on by the 2010 summer Deepwater Horizon (DWH) oil …

20-Year Assessment Of Total Suspended Sediment (Tss) Variability In Barataria Bay From Modis Ocean Color Using A Combination Of Adaptive Semi-Analytical And Neural Network Algorithms, Bijaylaxmi Sahoo

LSU Master's Theses

Barataria Bay, a hydrologically dynamic basin in the northern Gulf of Mexico, exhibits a distinct spatio-temporal distribution of total suspended sediment (TSS). However, studies on sediment distribution are limited by availability of in-situ data as well as the limitation of ocean color algorithms for suspended sediments in shallow optically complex waters. Barataria Bay TSS concentration profile is complex, influenced in the upper basin by fresh water sources such as the Davis Pond Freshwater Diversion, and in the lower bay by the river plume and marine influence near the mouth of the bay. To efficiently study the sediment dynamics in the …

An Analysis Of Hurricane Laura's Storm Surge In Cameron Parish Using Synthetic Storm Tracks, Climatology, And Statistics, Cameron Goff

LSU Master's Theses

Cameron Parish is a large coastal parish in southwest Louisiana that has been impacted by several powerful tropical cyclones. In 2020, the strongest hurricane in recorded history to ever hit this region, Hurricane Laura, set a state record for the highest storm surge measurement at 6.34 meters. I examine the climatology of tropical cyclone landfalls in this parish, looking for trends in intensity and frequency with time. I then compare the extreme surge of Hurricane Laura with a dataset of 645 synthetic tropical cyclones generated and used by the Coastal Hazards System for Louisiana. Plots comparing various meteorological statistics to …

Quantifying Mud Settling Velocity As A Function Of Turbulence And Salinity In A Deltaic Estuary, Michael W. Mcdonell

LSU Master's Theses

Mud settling velocity is controlled by flocculation, which in turn strongly depends on turbulence and on the chemistry and biology of the water-sediment mixture. As a result, mud settling velocity can be poorly constrained in coastal areas and vary in space and time by orders of magnitude. Here we quantified mud settling velocity in Barataria Basin, a deltaic estuary in Louisiana (USA), using three independent methods: eddy covariance (one station for 200 days), floc cameras (4 stations at one time), and Rouse profile inversion (14 stations, replicated 10-30 times each). Eddy covariance indicates that settling velocity increases with turbulence, at …

Wetland Soil Development Along Salinity And Hydrogeomorphic Gradients In Active And Inactive Deltaic Basins Of Coastal Louisiana, Amanda Fontenot

LSU Master's Theses

Coastal wetlands provide an abundance of ecosystem services that benefit society, such as essential habitat for commercial species, storm protection, nutrient cycling, and carbon storage. Louisiana faces rapid rates of relative sea level rise (natural subsidence and eustatic sea levels) that threaten wetland survival, which are amplified by a reduction of riverine sediment input. An important determining factor of marsh survival is the formation of wetland platform elevation, known as vertical accretion, which is determined by several processes including sediment deposition & erosion, below ground biomass (BGB) productivity, decomposition of organic matter, shallow & deep subsidence, and soil compaction. Feldspar …

Impact Of Oil And A Tropical Cyclone On An Omnivore And Herbivore Population In Salt Marshes Of Louisiana, Hannah K. Gordon

LSU Master's Theses

Terrestrial arthropods are the ideal ecological indicators for the health of a salt marsh. Salt marshes are under extreme continuous stressors including climate change, land loss, oil spills, and tropical cyclones. Such stressors impact trophic and species level interactions, food resources, dispersal and population size of insects. In the present study, we collected terrestrial arthropods from eleven sites around Barataria Bay, five sites were oiled and five sites were unoiled, to determine the impact of the redistribution of oil from the Deepwater Horizon oil spill. Site C6 was excluded from the oiled and unoiled data because it was in close …

Changes In Heat Metrics Following A Major Hurricane And Implications On Heat Stress, Cade Reesman

LSU Master's Theses

Tropical cyclones modify surface-atmosphere interactions in several ways, including the destruction of patches of tree canopy, increasing the direct and diffuse (shortwave) radiation reaching the surface. This addition of radiation at the surface impacts the sensible, latent, and substrate heat (energy) fluxes, generating heat anomalies along the hurricane’s track, which, among other effects, contributes to the higher post-hurricane surface air temperatures. This study consists of a case study on Hurricane Laura (2020) to examine hurricane defoliation impacts on heat stress metrics. Normalized difference vegetation index (NDVI) data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) identified the spatial extent of defoliation …

Effects Of Meteorologic Events On Wave Climate And Current Regime In A Shallow, Microtidal Bay, Jay S. Merrill

LSU Master's Theses

Along coastal Louisiana and within the shallow microtidal Barataria Bay estuary, meteorological events can play a primary role in influencing wave climate and circulation patterns. Understanding the effects of hurricanes and smaller tropical storms on hydrodynamic processes is important for constraining and predicting hydrodynamic variation in Barataria Bay, which, largely due to impacts from wave energy, is currently experiencing rapid wetland loss and is a major focus of coastal restoration efforts. Two bottom-mounted upward-facing Acoustic Current Doppler Profilers and wave, temperature, and depth recorders were installed in the lower portions of Barataria Bay to measure the wave climate and three-dimensional …

Blue Carbon In South Florida's Mangroves: The Role Of Large Roots And Necromass, Zoë I. Shribman

LSU Master's Theses

Blue carbon sequestration and storage in mangroves largely result from belowground biomass allocation in response to flooded anaerobic soil conditions and nutrient availability. Biomass allocation to belowground roots is a major driver of mangrove soil formation and organic matter accumulation leading to blue carbon storage potential. Belowground biomass sampling in mangroves is labor intensive, limiting data availability on biomass stocks, particularly for large roots (>20 mm diameter) and necromass (dead roots). The mangrove nutrient model (NUMAN) uses mostly literature values to parameterize a soil cohort approach to simulate depth distribution of root mass and organic carbon concentration. We evaluated …

Patterns And Drivers Of Introgression In Louisiana's Largemouth Bass (Micropterus Salmoides) Stocks, Colleen E. Walsh

LSU Master's Theses

In the southeastern U.S., populations of the popular sportfish Largemouth Bass (Micropterus salmoides; LMB) are often stocked with Florida Largemouth Bass (Micropterus salmoides floridanus; FLMB) to develop FLMB ancestry in systems north of its native peninsular Florida range, with the ultimate goal of creating trophy fisheries. Stock enhancement through introgression of FLMB ancestry can increase maximum potential size and growth in receiving populations, potentially through hybrid vigor of intergrade subspecies. We collected 60 fish and habitat data from six Louisiana lakes from 2018-2020 (N=360), quantified level of introgression of FLMB with fragment analysis at 12 microsatellite loci confirmed for subspecific …

Phragmites Australis Dieback In The Mississippi River Delta: Chemical Profiles Of Soil Types And Restoration Potential, Herie Lee

LSU Master's Theses

Since 2016, there has been widespread dieback of P. australis in the Lower Mississippi River Delta (hereafter referred to as Lower MRD, which is defined as the Birds Foot Delta) with relatively little to no signs of recovery. The cause of the current dieback is not fully understood. This thesis explores P. australis with emphasis on chemical profile characterization of different soil types and its effects on plant growth and the potential for restoration in the Lower MRD.

In chapter 2, I characterized the chemical profiles of soils collected from healthy and dieback stands of Phragmites, and from newly …

Hydrometeorological Responses To Abrupt Land Surface Change Following Hurricane Michael, Shannon Alexis Nelson

LSU Master's Theses

While many of the destructive environmental conditions associated with tropical cyclones are well recognized, tropical cyclone-induced defoliation, a reduction in green leaves and mature vegetation, has been largely overlooked as a source of environmental stress following tropical cyclone passage. The land surface change associated with defoliation reduces evapotranspiration and shade, thus altering boundary layer moisture and energy fluxes that drive the local water cycle, for many months after tropical cyclone passage. Understanding the potential for any hydrometeorological impacts arising from such abrupt land surface change is important for guiding future post-hurricane preparedness and recovery planning in coastal communities.

This thesis …

Investigating The Impact Of Meteoric Diagenesis On The Geochemistry Of Carbonate Eolianites, Eleuthera And Water Cay, The Bahamas, Graham S. Bonnot

LSU Master's Theses

The geochemical signatures imparted in major, minor, and trace elements, combined with light isotopes, suggest promising applications regarding the stabilization of meteorically altered limestone eolianites. Previous high-resolution studies have indicated that elements associated with carbonate diagenesis such as Mg and Sr can be valuable proxies for salinity and aragonite dissolution, respectively. In addition to testing these proxies, the analyses of several temperature-, diagenetic-, bioactive-, and redox-sensitive elements were evaluated using laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) to identify additional indicators during carbonate diagenesis. Two geochemical drivers of U were identified; (1) aragonite dissolution similar to Sr and (2) oxidation …

Plant Community Response To The Combined Effects Of Elevation, And Simulated Nutrient And Sediment Loading In Sagittaria Lancifolia-Dominated Wetlands, Donnie Day

LSU Master's Theses

Coastal wetlands are experiencing threats to their long-term sustainability brought about by the combined effects of relative sea-level rise and human modifications to hydrology, sediment delivery and nutrient loading. Restoration and management strategies can include adding sediment to the surface of deteriorating marshes to facilitate positive feedbacks among elevation, plant productivity, sediment trapping, and accretion; however, if delivered using nitrate-enriched river waters, belowground biomass and soil organic matter pools may be negatively affected, resulting in the acceleration of wetland loss. Overall, there is limited information on the combined effects of nutrient loading, sedimentation, and flooding dynamics in regulating feedbacks among …

Correlation Analysis Of Precipitation And River Flow With The Injection And Discharge Of The Three Gorges Dam And Reservoir, Lirong Yin

LSU Master's Theses

The Yangtze River has been the primary support of the resources and transportation of China. Its basin covers an area of 1.8 million square kilometers. The Three Gorges Dam and Reservoir on the Yangtze River is one of the world's largest dams. After the dam construction in 1997, the reservoir started injecting the reservoir to a size of over 600 km². The influence caused by the dam and reservoir on the river system has been overwhelming and destructive. The possible influence of this vast water body and the operation to maintain this waterbody's size and water level on …

The Life History And Population Dynamics Of Southern Flounder, Kenneth A. Erickson

LSU Master's Theses

Southern Flounder, Paralichthys lethostigma, are a coastal, estuarine-dependent flatfish species that inhabits the Southeastern US Atlantic Ocean and Gulf of Mexico. Throughout their range, Southern Flounder are exploited by both commercial and recreational fisheries. Recently, numerous sources have expressed concerns about Southern Flounder populations, with stock assessments indicating declines in spawning stock biomass and recruitment. To estimate life history traits needed for informed management, such as age, growth, and maturity, I collected 327 Southern Flounder from Louisiana and obtained 14,184 historical records from the Louisiana Department of Wildlife and Fisheries. Using a von Bertalanffy growth equation in a Bayesian …

Hydrodynamics, Sediment Transport, And Water Quality Of Two Contrasting Dredge Pits On The Louisiana Shelf, Robert Bales

LSU Master's Theses

Sediment is needed for coastal restoration in Louisiana and is often excavated offshore from both mud-capped and sandy dredge pits. The mined sand from mud-capped pits, like Sandy Point which is west of modern Mississippi Delta of Louisiana, was originally from a paleo river channel and later covered by mud from modern coastal processes. Sandy pits, like Caminada pit in eastern Ship Shoal on Louisiana shelf, generally experience higher energy conditions. To better understand the post-dredging effects on hydrodynamics, sediment transport, and water quality, two tripods were deployed at Caminada and Sandy Point pits in summer 2018 and 2019, respectively, …

Phosphorus Variability In The Area Of Influence Of The Mid-Barataria Sediment Diversion, Peter Mates

LSU Master's Theses

Man-made levees along the lower Mississippi River prevent delivery of sediment from building and maintaining Louisiana’s coastal wetlands. The Mid-Barataria sediment diversions is designed to reintroduce Mississippi River water, sediment, and nutrients into the sediment-starved Barataria Basin. Phosphorus (P) is an important macronutrient for regulating primary production in coastal marine ecosystems. Wetlands can serve as a sink or source for phosphorus to the overlying water column through various retention and release processes, dependent on concentration. Louisiana coastal systems can be phosphorus limited due to much higher concentrations of bioavailable Nitrogen in river water. The high soluble molar N:P ( >50:1) …

Reproductive Effort Of Montastraea Cavernosa Across Depth In The Context Of Both Climate Change Refugia And Emergent Disease, Jeanne Bloomberg

LSU Master's Theses

As coral populations on shallow reefs decline globally, mesophotic coral ecosystems (MCE) have been suggested as potential coral refugia in the face of climate changes, leading to the development of a comprehensive deep reef refugia hypothesis. The current study assesses the climate and disease refuge potential of MCEs in the U.S. Virgin Islands (USVI) for the gonochoric, broadcast-spawning species Montastraea cavernosa. Polyp, population, and total habitat fecundities were estimated across the species’ depth range, and changes to population oocyte production over time due to recent ecosystem disturbances were considered. The number of gonads producing oocytes in each polyp and oocyte …

Identification And Quantification Of Microplastic Pollution In Water Samples And Four Species Of Fish From The Mississippi River, Kerrin E. Toner

LSU Master's Theses

Microplastics (£5 mm) have become a persistent anthropogenic pollutant and a growing environmental concern with evidence of them being found throughout several ecosystems. In recent years, there has been a growing recognition that rivers play a major role in transporting plastics from the land to the sea. The Mississippi River is the largest river in North America, draining land populated by over 100 million people. With high numbers of microplastics found in the waters of the northern of the Gulf of Mexico, it is likely that the Mississippi River is the primary source of these plastics. This study quantifies and …

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 …

Microplastics In Mississippi River Fishes: A Watershed Approach, Ahmed Gad

LSU Master's Theses

Microplastics are plastic particles less than 5mm that come from different sources, such as industrial products, cosmetics, and the breakdown of the macroplastics. Microplastics derive from terrestrial sources but concentrate in flowing freshwaters where they may enter aquatic food webs. The northern Gulf of Mexico has shown very high microplastic concentrations, which are assumed to be sourced from the Mississippi River and its watershed. This study seeks to study microplastics in fish in the Mississippi River and the Gulf of Mexico. Fish stomachs and intestines from fish underwent chemical digestion, filtration, and microplastics identification and enumeration through FT-IR spectrometry. Chapter …

Effect Of Channelized And Unchannelized Lateral Outflow On Three-Dimensional Flow Structure And Sediment Transport Mechanisms In A River Delta, Mohammad Kifayath Chowdhury

LSU Master's Theses

Spatial and temporal patterns in three-dimensional flow structure have been linked to channel morphology and processes in many environments, including river meander bends, confluences-diffluences, and bedrock canyons. However, there is not yet an understanding of how channelized and gradual, distributed lateral outflows that are often prevalent in deltaic distributary systems influence three-dimensional flow structure and sediment transport mechanisms. This thesis presents an analysis of 3D flow structure data collected from Wax Lake Delta, a naturally developing river-dominated delta in the northern Gulf of Mexico. Three hydrographic surveys were conducted using boat-mounted acoustic Doppler current profiler (ADCP) at two sites: an …

Simulating Wave Dynamics In The Northern Gulf Of Mexico And Barataria Pass, Azadeh Razavi Arab

LSU Master's Theses

The coastal wetlands of Louisiana constitute ~40% of the wetlands in the United States. However, it suffers from 80% of the wetland losses in the whole country. In shallow coastal and estuarine environments, bed shear stresses related to wind waves contributes substantially to the edge erosion in the northern Gulf of Mexico (NGoM). Therefore, wave simulations in shallow estuarine areas are of great importance.

There are several challenges in simulating waves nearshore, especially over the shallow and nearly horizontal sea beds typical of the NGoM continental shelf and adjacent complex geometry estuaries: determination of the appropriate wind forcing dataset to …

Mass Spectrometric Calibration For Real -Time Hydrocarbon Detection, Makuachukwu Mbaegbu

LSU Master's Theses

Determining gas compositions from live well fluids on a drilling rig is critical for real time formation evaluation. However, development and utilization of a reliable mass spectrometric method to accurately characterize these live well fluids is always a challenging issue because of lack of a robust, quick and effectively selective instrument and method. The primary goal of this research is to understand reasons of such discrepancies in results between “good” spectra, and “poor” ones. The objectives are thus to identify the detection issues, calibrate and QA/QC the instruments, and analyze the results in lab settings. In this study, we used …

Role Of Coastal Environmental Conditions During Austral Winter On Plankton Community Dynamics And The Occurrence Of Pseudo-Nitzschia Spp. And Domoic Acid In Inhambane Province, Mozambique, Holly Kelchner

LSU Master's Theses

Harmful algal blooms (HABs) are increasing globally in frequency, persistence, and geographic extent. HABs pose a threat to economic stability, and ecosystem and human health. To date no incidences of marine toxins produced by phytoplankton have been recorded in Mozambique, which may be due to the absence of a monitoring program and general awareness of the potential threat. This study is the first documentation of the occurrence of a neurotoxin, domoic acid (DA), produced by the diatom genus Pseudo-nitzschia spp. along the east coast of Africa. The coast of Inhambane Province is a biodiversity hotspot where year-round Rhincodon typus (whale …

Reproductive Biology And Trophic Niche Of Hardhead Catfish In The Northern Gulf Of Mexico, Lucas G. Pensinger

LSU Master's Theses

Generally, marine fishes have very high fecundity with each female producing many small eggs which hatch into small larvae. However, Ariopsis felis, a species of marine catfish common to coastal Louisiana, has low fecundity and produces the largest eggs of the teleost fishes. Despite wide range and generally high abundance, we know very little of A. felis biology and population. The few existing studies of A. felis are older and often have questionable or unclear methodology.

I examined four aspects of A. felis reproductive biology: 1) reproductive timing,

2) fecundity, 3) length at first maturity, and 4) mouth brooding. …