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Full-Text Articles in Physical Sciences and Mathematics
Visualizing The Fate And Distribution Of Pahs In Spartina And Avicennia Tissues From Barataria Basin, La, Kristina Jeannette Sebastian
Visualizing The Fate And Distribution Of Pahs In Spartina And Avicennia Tissues From Barataria Basin, La, Kristina Jeannette Sebastian
LSU Master's Theses
During crude oil spill events, vegetation in marsh environments sequester polycyclic aromatic hydrocarbons (PAHs) from the crude oil by partitioning from the air phase through the waxy cuticle on the leaf surface. Recent studies from Macondo oil-impacted marshes have demonstrated that cycling of low molecular weight petrogenic PAHs occurs through the cuticle and other leaf tissue. At present, our understanding of how PAHs travel through the cuticle is coarse and limited by grab samples across the entire leaf, which preventing a full understanding the dynamics of PAH cycling in this environment. Multiphoton (MP) confocal microscopy visualizes the distribution of PAHs …
In Search Of Antarctica's Last Vegetation Refugium Within The Mcmurdo Dry Valleys, David Rau
In Search Of Antarctica's Last Vegetation Refugium Within The Mcmurdo Dry Valleys, David Rau
LSU Master's Theses
The McMurdo Dry Valleys, a hyper-arid cold polar desert located within the Transantarctic Mountains was once covered by vegetation. An in depth study of surface samples of various Neogene age, acquired throughout the Valleys, provide insight to the location of one of Antarctica’s last vegetation refugia. Boston University’s Antarctic Research Group has collected 82 surface samples from paleo lake sediments on 14 expeditions spanning 22 years in the McMurdo Dry Valleys. The ages of the samples are still not fully constrained, but 8 regions where samples were collected have been interpreted to range between 16.95 ± 0.17 to 4 Ma …
A Palynostratigraphic Investigation Of Holocene Coastal Texas Bays: Implications For Future Coastal Change, Shannon Marie Ferguson
A Palynostratigraphic Investigation Of Holocene Coastal Texas Bays: Implications For Future Coastal Change, Shannon Marie Ferguson
LSU Doctoral Dissertations
Although the Gulf of Mexico is one of the most studied basins in the world, a majority of the focus has been driven by petroleum exploration and/or on seismic and sedimentological facies models. Rarely has the intent of previous studies been to characterize the Holocene climatic record of coastal Texas. Of those studies that discuss Holocene vegetation change, the majority focus on the Mississippi River Delta, the Edwards Plateau or central Florida, leaving an absence of insight to western Gulf of Mexico climate changes. The Texas coastline stretches 595 km across almost 4° of latitude and the strong northwestern precipitation …
Effects Of Hydrologic Modifications On Flooding In Bottomland Hardwoods, Erin Johnson
Effects Of Hydrologic Modifications On Flooding In Bottomland Hardwoods, Erin Johnson
LSU Master's Theses
Complex fluvial processes influence floodplains. River modifications in the 1930s have affected hydrogeomorphic processes influencing the lower White River in southeastern Arkansas. The overall objective of this study was to better understand the hydrologic and geomorphic influence on the floodplain forest. We used the HEC-RAS model to quantify hydrologic relationships within the floodplain before and after 1930s river modifications. The model can replicate flooding within 3-5 m. Despite river modifications, HEC-RAS modeling showed headwater floods influenced the upper reach of the floodplain while backwater floods from the Mississippi River influenced the lower reach of the floodplain. Post-1930s incision that occurred …
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 …
Spatial Structure And Dynamics Of The Plant Communities In A Pro-Grading River Delta : Wax Lake Delta, Atchafalaya Bay, Louisiana, Melissa Carle
Spatial Structure And Dynamics Of The Plant Communities In A Pro-Grading River Delta : Wax Lake Delta, Atchafalaya Bay, Louisiana, Melissa Carle
LSU Doctoral Dissertations
River deltas are dynamic depositional environments that are controlled to varying degrees by coastal and fluvial forces. Plant communities in deltas respond to many of the same allogenic forces that shape delta geomorphology. This study examines the factors that influence plant community development, productivity, and species distributions in the Wax Lake delta, a young, actively pro-grading river delta in coastal Louisiana, USA. A species distribution map created using high-resolution 8-band WorldView-2 imagery was found to have an overall accuracy of 75 percent. Classification tree analysis suggested that most of the observed variation in plant species distributions within the delta can …
Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands, Jonathan M. Willis
Edaphic And Vegetative Controls On Mercury Cycling In Oligohaline Wetlands, Jonathan M. Willis
LSU Doctoral Dissertations
With the expansion of the human population and associated industries there is a concomitant increase in both resource utilization and the production of waste and deleterious by-products. Mercury is a naturally-occurring toxic metal with a complicated and unique biogeochemical cycle, and is often a contaminant of ecotoxicological concern in unindustrialized aquatic habitats. The research described herein was designed to elucidate multiple aspects regarding the behavior of mercury in oligohaline wetland habitats, particularly with respect to edaphic and vegetative effects, through a monitoring and characterization study as well as a series of manipulative experiments. The observational study, conducted in the wetlands …
Developing Tools To Identify Factors That Limit Production In Coastal Marshes, Vanessa Danielle Tobias
Developing Tools To Identify Factors That Limit Production In Coastal Marshes, Vanessa Danielle Tobias
LSU Doctoral Dissertations
Marsh loss is a problem in many areas around the world. In Louisiana’s coastal marshes, where Spartina patens is the most common plant, restoration and management seek to slow wetland loss rates that average approximately 77.4 km2/year. To combat the problem, scientists and managers require tools to determine local causes and evaluate the effectiveness of management techniques. Current methods for identifying factors that limit productivity in marshes are too time-consuming or expensive for wide-spread, regular use. Critical values of elemental concentrations in plant tissue are widely used to diagnose mineral deficiencies and toxicities in agricultural crops, however. I used the …
Influence Of Row Spacing And Debris Distribution On Vegetation And Small Mammals In Louisiana Pine Plantations, Anne M. Bechard
Influence Of Row Spacing And Debris Distribution On Vegetation And Small Mammals In Louisiana Pine Plantations, Anne M. Bechard
LSU Master's Theses
Site preparation after clearcuts directly affects surrounding small mammal populations. Differences in bed row spacing and arrangement of debris can impact structure and composition of vegetation communities, which influence small mammal habitat. We surveyed vegetation and small mammals in 2 different row spacings (14 ft and 20 ft) and 2 different debris distributions (piled and scattered) in 4 clearcuts owned by Weyerhaeuser in Louisiana during 2006-2007. Our objectives were to examine effects of row spacing and debris distribution on vegetation, to look at responses of small mammal densities to row spacing and debris distribution, and to see how small mammals …
Biogeomorphic Evaluation Of Caminada-Moreau Maritime Beach Ridges With Respect To Future Restoration Initiatives, Hannon Didier
Biogeomorphic Evaluation Of Caminada-Moreau Maritime Beach Ridges With Respect To Future Restoration Initiatives, Hannon Didier
LSU Master's Theses
Restoration efforts within the coastal zone of southern Louisiana have assumed greater importance in the wake of recent storms and ever increasing sea level rise. A poorly studied geomorphic structure known as the Caminada-Moreau maritime beach ridge complex exists along the southeastern Louisiana coastline between Grand Isle and the Port of Fourchon. Active subsidence in the area has reduced the overall elevation of these structures, decreasing the live cover of its most noticeable feature, stands of Quercus virginiana (live oak), along the ridge spines. Elevation data was gathered along and across four randomly selected ridges in the study area with …