Physical Sciences and Mathematics Commons^™

The Morphodynamic Interaction Of River Deltas And Their Marshes, Kelly M. Sanks

Graduate Theses and Dissertations

Globally, many of the largest river deltas contain vast marsh platforms that are currently threatened due to a combination of anthropogenic alterations to rivers and increasing relative sea level rise. Restoration and management plans for river deltas depend on optimizing riverine sediment accumulation in marsh platforms. However, the accumulation of organic material in marsh platforms is often neglected in predictive models and the interaction of ecogeomorphic processes governing marsh accumulation with the physical processes governing river delta growth is poorly understood.

Herein, I investigate this complex relationship through a combination of field and experimental studies. I show that in coastal …

Advances In Assessing Flood Hazard And Sediment Dynamics At The Coast, Hannah Baranes

Doctoral Dissertations

Earth’s coastlines are shaped by geophysical and human dynamism. Waves, tides, currents, and sea level change reconfigure coastal environments on hourly to centennial timescales, and the coast is experiencing the fastest economic and population growth rates in the world. This coexistence of a dynamic environment and human development makes coastal communities uniquely vulnerable to natural hazards. Climate change is expected to exacerbate flooding and erosion hazards in the future; thus, it is critical that we understand the underlying physical drivers of coastal change. The overarching goal of this dissertation is to improve the mechanistic understanding and quantification of dynamic processes …

Early Life History Of Tarpon (Megalops Atlanticus) In South Carolina Estuaries: Assessment Of Juvenile Recruitment And Validity Of Aging And Back-Calculation Methods, Garrett M. Elmo

Electronic Theses and Dissertations

No abstract provided.

Tidal-Groundwater Study Of The Slaughter Beach Salt Marsh In Slaughter Beach, De, Michael Powers

West Chester University Master’s Theses

Seasonal and decadal monitoring of salt marsh at Slaughter Beach, DE documented long-term and short-term variations in number and sizes of salt ponds. Over 400 salt ponds ranging in size between 0.5 m² to 0.11 km² were identified on 5.5 km² salt marsh platform. The purpose of this study is to quantify hydrologic conditions and measure groundwater discharge of a salt marsh, particularly the impact of tidal forces on groundwater fluctuation.

Four wells with nests of mini-piezometers with ONSET Pressure Transducers were installed along a transect crossing the largest salt pond (0.11 km²) in the …

The Importance Of Landscape Position Information And Elevation Uncertainty For Barrier Island Habitat Mapping And Modeling, Nicholas Matthew Enwright

LSU Doctoral Dissertations

Barrier islands provide important ecosystem services, including storm protection and erosion control to the mainland, habitat for fish and wildlife, and tourism. As a result, natural resource managers are concerned with monitoring changes to these islands and modeling future states of these environments. Landscape position, such as elevation and distance from shore, influences habitat coverage on barrier islands by regulating exposure to abiotic factors, including waves, tides, and salt spray. Geographers commonly use aerial topographic lidar data for extracting landscape position information. However, researchers rarely consider lidar elevation uncertainty when using automated processes for extracting elevation-dependent habitats from lidar data. …

Assessment And Correction Of Lidar-Derived Dems In The Coastal Marshes Of Louisiana, William M. Lauve

LSU Master's Theses

The onset of airborne light detection and ranging (lidar) has resulted in expansive, precise digital elevation models (DEMs). DEMs are essential for modeling complex systems, such as the coastal land margin of Louisiana. They are used for many applications (e.g. tide, storm surge, and ecological modeling) and by diverse groups (e.g. state and federal agencies, NGOs, and academia). However, in a marsh environment, it is difficult for airborne lidar to produce accurate bare-earth measurements and even accurate elevations are rarely verified by ground truth data. The accuracy of lidar in marshes is limited by the sensor’s resolution …

An Airlifted Tidal Mesocosm For Oil Degradation Studies, Daniel Christopher Alt

LSU Doctoral Dissertations

Mesocosms were constructed to allow scientists to isolate variables in a microtidal marsh environment, mimicking the natural conditions found in Terrebonne Bay. The control offered by these mesocosms is given by a process control system that takes user inputs and automates water movement. Twelve mesocosms were constructed, each holding 4.02 m³ (142 ft³) of marsh soil and 3.88 m³ (137 ft³) of water to give 3 experimental levels and a control, all in triplicate.

Each mesocosms that was constructed contained marsh plants in soil plugs 9 feet in diameter and 3 feet deep. These …

Investigation Of Pattern Formation In Marine Environments Through Mathematical Modeling And Analysis Of Remotely Sensed Data, Sofya Zaytseva

Dissertations, Theses, and Masters Projects

Pattern formation in ecological systems refers to a nonuniform distribution of animal and plant species across a landscape. Pattern formation can be observed in many aquatic and terrestrial systems and can provide important insights into their dynamics and ability to cope with environmental changes. In this dissertation, we focus on pattern formation in tidal marshes and oyster reefs, two important habitats that provide a number of essential ecosystem services. Both of these systems have also experienced dramatic losses, prompting much research to investigate their dynamics as and viable restoration and management strategies. The first part of this dissertation focuses on …

An Evaluation Of Marsh Shoreline Erosion And Sediment Deposition In The Grand Bay National Estuarine Research Reserve, Mississippi, Usa, Joseph Terrano

USF Tampa Graduate Theses and Dissertations

Coastal marshes serve important ecologic and economic functions, such as providing habitat, absorbing floodwaters and storm surges, and sequestering carbon. Throughout the northern Gulf of Mexico, coastal marshes are disappearing due to wave attack, sea-level rise, sediment export, and subsidence. Marsh area increases when sediments accumulate at the marsh shoreline, accrete vertically, and when non-marsh areas are colonized by marsh vegetation. Marsh shoreline erosion results in net marsh loss when transgression rates at the marsh-water edge exceed upland-marsh migration. The balance between marsh destroying and marsh creating processes determines the long-term survivability of a marsh system. Thus, processes of shoreline …

Pesticide Concentrations In Water From A Southern Louisiana Marsh Influenced By The Mississippi River, Kara Leigh Callicott

LSU Master's Theses

The pesticides atrazine, chlorothalonil, and fipronil are common surface water contaminants due to their high rates of application and their chemical properties. This study investigates the introduction of contaminants into coastal wetlands via the Bayou Lamoque Mississippi River control structure in Plaquemines Parish, Louisiana. A protocol for environmental sampling using Continuous Low-level Aquatic Monitoring (C.L.A.M.) C-18 disks is described, along with effective solid phase extraction (SPE) and gas chromatography mass spectrometry (GC/MS) methodology for the determination of atrazine, chlorothalonil, and fipronil in surface water. Average concentrations of atrazine and chlorothalonil inside the Bayou Lamoque freshwater diversion structure for the months …

Holocene Sedimentary Responses To Growth Faulting In A Back-Barrier Setting: East Matagorda Peninsula, Texas, Phillip Wolfe

Theses and Dissertations--Earth and Environmental Sciences

The structural framework of the northern Gulf of Mexico coastal zone is characterized by numerous growth fault systems. Neotectonic processes in coastal marshes in this region have been shown to be important drivers of relative sea-level rise as well as having significant influence on marsh accretion processes. One active growth fault has been identified at East Matagorda Peninsula, Texas. To characterize the Holocene behavior of this fault and the consequent sedimentary responses, a suite of fallout radionuclides (⁷Be, ¹³⁷Cs, ²¹⁰Pb) and radiocarbon, supplemented by sediment physical property data have been used to determine sediment mixing depths, …

Oligohaline Wetland Response And Recovery Following Storm-Driven Saltwater Intrusion In Coastal Louisiana, Whitney Marie Kiehn

LSU Doctoral Dissertations

Coastal ecosystems occupy an interface between land and ocean, making them vulnerable to a variety of natural and anthropogenic disturbances. Large, episodic disturbances (mega-disturbances) cause immediate and long-lasting changes to coastal wetland plant communities and soils by changing the environmental conditions in which they exist. Here I examined the impacts of storm-induced saltwater intrusion and post-intrusion conditions on the structure and growth of an oligohaline wetland plant community, and on wetland soil biogeochemistry and conditions during and after saltwater intrusion. In the greenhouse, a six-week saltwater intrusion reduced canopy cover and species richness. Once intrusion stress was alleviated, plant community …

A Comparison Of Ecological Conditions And Relationships In An Altered Wetland And An Unaltered Wetland, Mark Kiyoshi Hurst

USF Tampa Graduate Theses and Dissertations

The purpose of the study is to identify and quantify the hydrologic and ecologic differences between two adjacent sections of Colt Creek; one section unaltered and one section altered by clearing and drainage. These differences were measured by monitoring water levels, groundcover vegetation in each of the two areas, and monitoring numbers and species of birds utilizing the two areas. Surface water levels were measured in three locations: in the historic Colt Creek flow way, in the ditch draining the creek, and in an adjacent wetland strand. In addition, a shallow monitor well in the creek was used to measure …

A Look At The Integration Of Wetlands And Hazard Mitigation Planning In Coastal Louisiana, Kathleen Melissa Bowers

LSU Master's Theses

Due to the destruction of the damaging hurricanes of 2005, Katrina and Rita, more effort has gone into the rebuilding and prevention of future disasters along the Louisiana coast than ever before. This research focuses on the use of wetlands, in the ten coastal parishes of Louisiana, as a mitigation effort aiding in the protection of coastal communities. Using content analysis and decision support software, a wetland ranking was created that represents how wetlands are utilized and protected within each parish. Criteria gathered from the plans include how many times wetlands were mentioned, collaboration with the state and other agencies, …

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 …

Physical And Microbial Responses Of Dredged Sediment To Two-Soil-Stabilizing Amendments, Xanthan Gum And Guar Gum, For Use In Coastal Wetland Restoration, Lauren Land

LSU Master's Theses

In wetland sediments, organic matter provides a substrate for microbial activity. During metabolism, microbes release extracellular polymeric substances, which accumulate to bind soil particles. A similar concept can be implemented on a large scale to reduce wetland loss in Louisiana. Hypothetically, hydraulically dredged sediment can be amended with polymer and deposited on subsiding marshes as a restoration method where the polymer increases sediment stabilization until plants become established. This lab study focused on investigating the influence of natural polymer additions on particle aggregation to increase sediment stability and the effects on microbial activity. Sediments from three sites (i.e. freshwater, intermediate, …

Landscape Analysis Of Vegetation Change In Coastal Louisiana Following Hurricanes Katrina And Rita, Gregory Dean Steyer

LSU Doctoral Dissertations

Investigations of hurricane disturbances on coastal vegetated communities are common, but relatively few are comprehensive across broad geographic regions. The 2005 hurricanes, Katrina and Rita, exposed Louisiana coastal landscapes to physical modifications and extensive and prolonged flooding, resulting in measurable physicochemical changes. This research used remote sensing and field investigations to regionally assess (1) porewater salinity and sulfide impacts to and recovery of coastal Louisiana vegetation communities, and (2) the importance of mineral sediment deposition on accretionary processes. Hurricane effects were most direct and prominent in eastern Louisiana from Katrina and western Louisiana from Rita, compared to central Louisiana exposed …

Survival, Habitat Use, And Movements Of Female Mallards Wintering In Southwestern Louisiana, Paul Thomas Link

LSU Master's Theses

Little information is available concerning survival, habitat use, and movements of mallards (Anas platyrhychos) wintering on the Gulf Coast Chenier Plain (GCCP). Quantitative data on these parameters would be useful in making effective management decisions by GCCP waterfowl managers. Accordingly, I radio-marked 135 female mallards during winters 2004-2005 and 2005-2006 in southwestern Louisiana. My estimated survival rate for both winters combined was 0.68 ± 0.06 and did not differ by female age. Hazard ratios indicated that radio-marked females were 21-24 times more likely to die during hunted time periods than during non-hunted time periods. Estimated hunting and non-hunting mortality rates …

A Community Approach To Identifying Essential Fish Habitat Of Spotted Seatrout, Cynoscion Nebulosus, In Barataria Bay, La, Pamela Sharon Dawn Macrae

LSU Doctoral Dissertations

Louisiana wetlands are disappearing at a dramatic rate, providing an impetus for identifying essential fish habitat (EFH) in this region. The distribution, relative abundance, biomass, length and food web dynamics of spotted seatrout, Cynoscion nebulosus, as well as the fish assemblage structure were examined in Barataria Bay, LA, in relation to habitat type and physical/chemical properties of the water. All fish were collected from three sites located along a salinity gradient, each contained the three habitat types of interest: marsh edge, soft bottom and oyster shell, and were sampled monthly from May 2003 to May 2004 with gillnets. Habitat preference …

The Effects Of Nutrient Enrichment On The Decomposition Of Belowground Organic Matter In A Sagittaria Lancifolia - Dominated Oligohaline Marsh, Kristen Raye Laursen

LSU Master's Theses

Wetlands improve water quality through sedimentation and the uptake of excess nutrients. As human population increases in the coastal zone, wetlands receive greater nutrient inputs. These additional nutrients may accelerate microbial activity, leading to faster decomposition rates. This decomposition could exceed belowground organic matter production, resulting in a net reduction in soil organic matter accumulation and vertical marsh accretion. The effects of nutrient enrichment on belowground organic matter decomposition in subtropical marshes have received little attention. As such, this research examined the effects of four levels of nitrogen combined with two levels of phosphorus enrichment on belowground decomposition through the …

A Comparison Of Consumer's Surplus And Monopoly Revenue Estimates Of Recreational Value For Two Utah Waterfowl Marshes, C. Holden Brink

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Demand curves were estimated for waterfowl hunting and nonconsumptive recreational use from use rate and variable expenditure data collected at the Bear River Migratory Bird Refuge and the Farmington Bay Waterfowl Management Area during fiscal 1969. Consumer's surplus and monopoly revenue estimates were then derived from the demand functions. Adjusted estimates of consumer's surplus for waterfowl hunting amounted to $7,260 per year at Bear River and $11,400 per year at Farmington Bay. For nonconsumptive recreation annual consumer's surplus was estimated to be $18,700 at Bear River and $3,760 at Farmington Bay. Monopoly revenue estimates were between one-half and one-fourth the …