Digital Commons Network^™

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 …

If You Build It, Will They Come? Assessing Habitat Quality For Marsh Birds At Created Marshes In Southeastern Louisiana, Katherine Aylett Lipford

LSU Master's Theses

Wetland loss occurs at an alarming pace globally, with extremely high rates along the northern Gulf of Mexico. Louisiana loses a football field of wetland every 100 minutes: that is 77,000 m² of wetland bird habitat lost daily. In Louisiana, marsh creation projects combat wetland loss, and while wildlife habitat is often used as a justification for restoration, wildlife receives little to no consideration during and after construction. Habitat characteristics such as site-specific hydrology, vegetation composition, and habitat structure affect the abundance of wetland birds and understanding these features is crucial to creating habitat that will benefit birds. My …

Uavs And Deep Neural Networks: An Alternative Approach To Monitoring Waterfowl At The Site Level, Zachary J. Loken

LSU Master's Theses

Understanding how waterfowl respond to habitat restoration and management activities is crucial for evaluating and refining conservation delivery programs. However, site-specific waterfowl monitoring is challenging, especially in heavily forested systems such as the Mississippi Alluvial Valley (MAV)—a primary wintering region for ducks in North America. I hypothesized that using uncrewed aerial vehicles (UAVs) coupled with deep learning-based methods for object detection would provide an efficient and effective means for surveying non-breeding waterfowl on difficult-to-access restored wetland sites. Accordingly, during the winters of 2021 and 2022, I surveyed wetland restoration easements in the MAV using a UAV equipped with a dual …

Influences On Participation In The National Flood Insurance Program’S Community Rating System In Coastal Counties In Louisiana, Mississippi, Alabama, And Florida, Jennifer E. Argote

LSU Doctoral Dissertations

The National Flood Insurance Program provides an incentive-based program, the Community Rating System (“CRS”), to encourage communities to improve their hazard mitigation protocols to better protect against and prevent flood-related hazards. This dissertation analyzes factors that influence participation and points scored within the CRS to gain an understanding of the conditions under which communities are willing and able to take advantage of an incentive-based flood hazard mitigation program. It also includes an analysis of survey responses from 41 coastal county floodplain and CRS managers to gauge their opinions on the CRS and how it can be improved to better serve …

Can Gulf Ribbed Mussels Enhance Coastal Restoration Projects In A Future With Climate Change?, Skylar Liner

LSU Master's Theses

Living shorelines present one restoration approach using biotic elements (via ecosystem engineers) to stabilize shorelines and increase valuable habitat. Gulf ribbed mussels (Geukensia granosissima) are important ecosystem engineers within brackish and salt marshes in the northern Gulf of Mexico, and can increase nutrient availability, enhance marsh vegetation production, and potentially improve shoreline stability. It is unknown whether mussels will maintain these functions as future climate change predicts increases in temperature and water level, which may exceed the mussel’s tolerance. A field survey conducted during the summer of 2022 identified the daily maximum temperature at the marsh surface, where mussels naturally …

Gulf Sturgeon Mesohabitat Use And Movement In The Lower Pearl River Louisiana-Mississippi, Amanda Popovich

LSU Master's Theses

After spring migrations to natal rivers Gulf Sturgeon Acipenser oxyrinchus desotoi reside in freshwater holding areas prior to fall emigrations to nearby estuaries. Limited published information on the physical habitat characteristics of these holding areas is available, especially for juvenile fish in the western portion of the Gulf Sturgeon’s distribution. To further investigate freshwater occupancy and movement patterns, 32 acoustic receivers were deployed from late April to October of 2021 and 2022 in 1600-m reaches distributed throughout the lower Pearl River, Louisiana-Mississippi, the westernmost river within their distribution. Generalized linear mixed models and multi-state models were used to determine what …

Accurately Valuing Blue Carbon Sequestration And Storage To Foster Coastal Conservation Via Evidence-Based Policymaking And Model Environmental Services Statute Methodologies, John Shelton Penton Jr

LSU Doctoral Dissertations

Blue carbon ecosystems, especially mangrove forests, provide one of nature’s most effective means for sequestering carbon from the atmosphere and storing it in subsurface soils. The six nearshore coastal morphologies found in tropical and subtropical regions each possess a conspicuous environmental signature that can be employed to accurately estimate and predict mangrove forests’ carbon storage in above-ground biomass, below-ground biomass, and the soils by system type. The consistent geomorphology and geophysical processes within each of these coastal environmental settings, that is, the wave and tidal forcings, the rate of coastal sediment accretions, nutrient load and limitations (e.g., nitrogen-to-phosphorus …

Baldcypress (Taxodium Distichum) And Their Growth And Development Under Abiotic Stressors Related To Restoration Efforts, George Washburn

LSU Doctoral Dissertations

Baldcypresss (Taxodium distichum (L.) Rich.) forests are crucial to the Southeast coastal region for the trees’ ecosystem services. Many organizations have been trying to restore the ghost and dead forests found throughout the Gulf region through restoration events. Baldcypress seedlings and saplings face several abiotic and biotic stressors, including but not limited to elevated levels of salinity, nutrients, temperature, and light intensity. These stressors can be the limiting factor in the success or failure of these massive planting efforts.

To assess which stressors were of most concern to the restoration efforts, we conducted common garden experiments with baldcypress seedlings …

Hydrogeologic Investigation Of A Covered Karst Terrain, Joseph Peter Honings

LSU Doctoral Dissertations

Increasing demand for water for agricultural use within the Dougherty Plain of the Southeastern United States has depleted surface water bodies. In karstic landscapes, such as the Dougherty Plain in southwest Georgia where the linkages between surface and ground waters are close, there is a need to understand the physical characteristics of the subsurface that allow these close linkages. Having a better understanding of the subsurface characteristics will aid numerical modeling efforts that underpin policy decisions and economic analyses. Two common features on this karstic landscape are draws and geographically isolated wetlands. Using LiDAR, aerial imagery, and ground-penetrating radar, this …

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 …

Local And State Climate Initiatives In Louisiana Since 2005: Content And Thematic Analyses, Jessie F. Parrott

LSU Master's Theses

Louisiana is uniquely exposed to severe weather because of its geography and climate. Louisiana’s extreme weather is exacerbated by anthropogenic climate change, which will worsen in the future. The risks its population and environment are exposed to has generated several policies and planning documents, nine of which are analyzed in this thesis. Three plans are from the state level, three are from the parish level, and three are from the urban (New Orleans) level. These planning documents pose various adaptation and mitigation actions to ameliorate and address multiple climate issues. These actions utilize specific mitigation strategies. The content and thematic …

Breeding Ecology Of Mottled Ducks In Southwestern Louisiana, Elizabeth Sophia Bonczek

LSU Doctoral Dissertations

Mottled ducks are a resident species found in the southern United States that rely on coastal marsh and associated habitat to fulfill the needs of the entirety of their annual cycle. Population monitoring has revealed declines in western Gulf Coast (WGC) mottled ducks since 2008. Mottled duck populations are influenced by survival and recruitment, and changes in these factors may contribute to population declines. The overarching goal of this project was to identify the mechanisms potentially limiting WGC mottled ducks.

I captured adult female mottled ducks during molt on Rockefeller Wildlife Refuge and adjacent lands in southwestern Louisiana from 2017–2019. …

Effects Of Hypoxia And High Temperature On Eastern Oysters: Investigating Differential Tolerance In Populations And Ploidies, Nicholas C. Coxe

LSU Master's Theses

Increasing prevalence of hypoxia in estuarine waters can pose a serious threat to eastern oysters (Crassostrea virginica). While oysters are considered more tolerant to hypoxia than many other bivalves, their tolerance at temperatures of 28 °C and above, typical in northern Gulf of Mexico estuaries in the summer, is not well characterized. Moreover, it is unknown whether differences in hypoxia tolerance exist among oyster populations or between diploid and triploid oysters. To investigate population differences, wild oysters were collected from four estuaries in the northern and northwestern Gulf of Mexico and spawned. In a series of studies, the …

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 …

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, …

Bat Habitat Use And Activity In Forests Of Central Louisiana, Jane M. Kunberger

LSU Master's Theses

In the southeastern U.S., where forests are the primary land cover type and trees are often harvested for production purposes, understanding how forestry practices influence bat distributions is critical for bat conservation and management. It is also important for researchers to quantify and report variation in the performance of automated recordings units (ARUs) used to survey for bats because several key features of ARUs (e.g., microphone sensitivity, triggering thresholds) can influence an ARUs ability to detect bat calls. My goals were (1) to examine the influence of forest management practices on seasonal bat species occurrence and activity in central Louisiana, …

Trophic Relationships Between Tadpoles And Other Aquatic Organisms In Sub-Tropical Ponds, Kira Cates

Honors Theses

No abstract provided.

Collisions On Campus: Species-Specific Susceptibility Of Resident And Migrant Birds To Window Strikes At Louisiana State University, Jordan A. Mouton

Honors Theses

No abstract provided.

The Effect Of Channel Stability On Fish Condition And Diet In Thompson Creek, La, Alexia Lagrone

Honors Theses

No abstract provided.

Connecting The Dots: Transmission Of Stony Coral Tissue Loss Disease From The Marquesas To The Dry Tortugas, Thomas Dobbelaere, Daniel M. Holstein, Erinn M. Muller, Lewis J. Gramer, Lucas Mceachron, Sara D. Williams, Emmanuel Hanert

Faculty Publications

For the last 7 years, Florida's Coral Reef (FCR) has suffered from widespread and severe coral loss caused by stony coral tissue loss disease (SCTLD). First observed off the coast of Miami-Dade county in 2014, the outbreak has since spread throughout the entirety of FCR and some areas of the Caribbean. However, the propagation of the disease through FCR seemed to slow down when it reached the western end of the Marquesas in August 2020. Despite being present about 30 km (similar to 20 miles) from the Dry Tortugas (DRTO), SCTLD was not reported in this area before May 2021. …

Singing Strategies Are Linked To Perch Use On Foraging Territories In Heart-Nosed Bats, Grace C. Smarsh, Ashley M. Long, Michael Smotherman

Faculty Publications

Acoustic communication allows animals to coordinate and optimize resource utilization in space. Cardioderma cor, the heart-nosed bat, is one of the few species of bats known to sing during nighttime foraging. Previous research found that heart-nosed bats react aggressively to song playback, supporting the territorial defense hypothesis of singing in this species. We further investigated the territorial defense hypothesis from an ecological standpoint, which predicts that singing should be associated with exclusive areas containing a resource, by tracking 14 individuals nightly during the dry seasons in Tanzania. We quantified the singing behavior of individuals at all perches used throughout the …

Application Of Gravity Data For Hydrocarbon Exploration Using Machine Learning Assisted Workflow, Oluwafemi Temidayo Alaofin

LSU Master's Theses

Gravity survey has played an essential role in many geoscience fields ever since it was conducted, especially as an early screening tool for subsurface hydrocarbon exploration. With continued improvement in data processing techniques and gravity survey accuracy, in-depth gravity anomaly studies, such as characterization of Bouguer and isostatic residual anomalies, have the potential to delineate prolific regional structures and hydrocarbon basins. In this study, we focus on developing a cost-effective, quick, and computationally efficient screening tool for hydrocarbon exploration using gravity data employing machine learning techniques. Since land-based gravity surveys are often expensive and difficult to obtain in remote places, …

Reef Sediments Can Act As A Stony Coral Tissue Loss Disease Vector, Michael S. Studivan, Ashley M. Rossin, Ewelina Rubin, Nash Soderberg, Daniel M. Holstein, Ian C. Enochs

Faculty Publications

Stony coral tissue loss disease (SCTLD) was first observed in 2014 near Virginia Key in Miami-Dade County, Florida. Field sampling, lab experiments, and modeling approaches have suggested that reef sediments may play a role in SCTLD transmission, though a positive link has not been tested experimentally. We conducted an ex situ transmission assay using a statistically-independent disease apparatus to test whether reef sediments can transmit SCTLD in the absence of direct contact between diseased and healthy coral tissue. We evaluated two methods of sediment inoculation: batch inoculation of sediments collected from southeast Florida using whole colonies of diseased Montastraea cavernosa, …

Developing A Watershed-Based Plan Evaluation Framework For Socio-Ecological Network Analysis In The Upper Pontchartrain Basin, Lindsey R. Lamana

LSU Master's Theses

Louisiana's efforts to create regional watershed planning under the Louisiana Watershed Initiative (LWI) suggest the need to evaluate existing governance systems such as the coordination, development, and implementation of plans. The Network Analysis and Plan Evaluation (NAPE) Framework developed in this study answers initial questions related to the LWI’s long-term resilience outcomes from the content analysis and extraction of relational data in plans of LWI Region 7 located in the Upper Pontchartrain Basin. Actor-Plan Coordination Networks reveal the coordination and collaboration of entities, and a Network of Plans presents the integration of planning documents in the Region. Local government organizations …

Analysis Of The Photodegradation Of The Pro-Herbicide Benzobicyclon Hydrolysate Using A Seawater Gradient And Constituent Ions, Margaret A. Knight

Honors Theses

No abstract provided.

Floodplain Forests Vegetation Dynamics Driven By Water Deficits Across Scales, Nga Thanh Nguyen

LSU Doctoral Dissertations

Restoration of floodplain ecosystems relies on identifying the most crucial hydrologic process which has been altered by human and climate. Flooding is a well-known dominant hydrologic process for floodplain ecosystems, but surprisingly little is known about drought's role in structuring ecosystems. In addition, several issues remained uncertain, such as the nature of drought within floodplains and the sensitivity of floodplain species-specific growth to climate. These gaps of understanding have in common in missing observations of mechanistic pathways of vegetation response to water deficits at multiple scales in time and space.Generally, this research contributed to floodplain management by expanding our understanding …

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 …