Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Denitrification (2)
- Louisiana (2)
- Oil and gas platforms (2)
- Salt marsh (2)
- Aflp (1)
-
- Age and growth (1)
- Alabama (1)
- Aluminum (1)
- Backfilling (1)
- Batoid (1)
- Benthos (1)
- Biological invasions (1)
- Bottomland hardwoods (1)
- Brown-marsh (1)
- Caloric value (1)
- Coastal marsh (1)
- Coastal wetlands (1)
- Continental shelf (1)
- Copepod (1)
- Coral (1)
- Decapod crustaceans (1)
- Demersal (1)
- Denitrification in agricultural watersheds (1)
- Die-back (1)
- Dispersal (1)
- Ecosystem effects (1)
- Egg production (1)
- Elasmobranch (1)
- Essential fish habitat (1)
- Ferric iron reduction (1)
Articles 1 - 17 of 17
Full-Text Articles in Physical Sciences and Mathematics
Benthic Communities In The Northern Gulf Of Mexico Hypoxic Area: Potential Prey For Demersal Fish, Melissa Millman Baustian
Benthic Communities In The Northern Gulf Of Mexico Hypoxic Area: Potential Prey For Demersal Fish, Melissa Millman Baustian
LSU Master's Theses
Bottom-water hypoxia (≤2 mg O2 l-1) usually occurs on an annual basis on the Louisiana/Texas continental shelf from mid-May through mid-September over a large area (up to 20,000 km2 in mid-summer). The effects of hypoxia on the benthic infauna (potential prey) for demersal fish were examined, because changes in optimal diet can lead to negative impacts on growth and reproduction. Benthic samples were taken in three areas (inshore and offshore out of hypoxia and in the hypoxic area) during August 2003. Samples were also taken monthly from September 2003 to October 2004 at a fixed station …
Nitrate Reduction And Methane Formation As Influenced By Iron-Centered Intermediate Redox Processes In Rice Soils, Bin Huang
LSU Doctoral Dissertations
Rice fields are a major source of the greenhouse gases methane (CH4) and nitrous oxide (N2O) and contribute to nitrate (NO3-) pollution in waters. Ferric iron (Fe3+) and manganic manganese (Mn4+) are two intermediate alternative electron acceptors (AEAs) capable of regeneration in freshwater soils. In this investigation, the influences of iron-centered intermediate redox processes on NO3- reduction and CH4 formation in rice soils were studied using soil slurries, soil columns, and potted rice. Reduction of Fe3+-centered intermediate AEAs was mainly mediated by obligate anaerobes …
Denitrification And Greenhouse Gas Emissions From Cultivated And Wetland Alluvial Soils, Sami Ullah
Denitrification And Greenhouse Gas Emissions From Cultivated And Wetland Alluvial Soils, Sami Ullah
LSU Doctoral Dissertations
Agricultural development in the Mississippi River Basin has contributed to an 3-fold increase in NO3 loading of the river. Increased NO3 loading is a primary cause of eutrophication in the northern Gulf of Mexico. Identification of best management practices (BMPs) to reduce NO3 loss and wetlands restoration to remove NO3 through denitrification are critically needed. The objectives of this research were to determine factors controlling denitrification potential of different landscape units in an agricultural watershed and quantify the effects of BMPs and organic C amendments on denitrification rates of cultivated lands and restored forested wetlands. N2O, CH4 and CO2 emissions …
Effects Of Adding Sediment To A Fresh Water Thin Mat Floating Marsh, Kate Carpenter
Effects Of Adding Sediment To A Fresh Water Thin Mat Floating Marsh, Kate Carpenter
LSU Master's Theses
Floating marshes are wetlands of emergent vascular vegetation which have a significant mat of live and dead roots, decomposing and dead organic material, and mineral sediments. This mat moves vertically as ambient water levels rise and fall. These marshes have unique hydrology in that overland sheet flow is reduced or eliminated leaving no inorganic sediment input, but there is extensive belowground water exchange. The effect of significant sediment introduction into wetlands with floating marshes is unknown. The purpose of this study was to observe the marsh mat response to Mississippi River sediment addition and measure species composition change and growth …
Nekton Utilization Of Black Mangrove (Avicennia Germinans) And Smooth Cordgrass (Spartina Alterniflora) Sites In Southwestern Caminada Bay, Louisiana, Melanie Christine Caudill
Nekton Utilization Of Black Mangrove (Avicennia Germinans) And Smooth Cordgrass (Spartina Alterniflora) Sites In Southwestern Caminada Bay, Louisiana, Melanie Christine Caudill
LSU Master's Theses
This is the first study to compare nekton use and habitat value among Spartina alterniflora (Spartina), Avicennia germinans (black mangrove), and transition (S. alterniflora and A. germinans) sites within Louisiana's salt marsh-mangrove ecotone. Fishes and crustaceans were collected in Caminada Bay during fall 2003 and spring 2004 using 4 m2, bottomless lift nets. Although analyses were unable to demonstrate significant differences in fish (p=0.0753) and crustacean (p=0.1457) densities and species composition (p=0.8801) across sites, habitat-specific trends in nekton use were evident. Fishes, including gulf killifish and sheepshead minnows, showed affinities for the Spartina site, while crustaceans, especially white shrimp, were …
Geologic Variability And Holocene Sedimentary Record On The Northern Gulf Of Mexico Inner To Mid-Continental Shelf, Triniti A. Dufrene
Geologic Variability And Holocene Sedimentary Record On The Northern Gulf Of Mexico Inner To Mid-Continental Shelf, Triniti A. Dufrene
LSU Master's Theses
Sidescan Sonar, chirp sonar sub-bottom profiles, and grab samples were collected on the north-central Gulf of Mexico continental shelf as part of an interdisciplinary study mapping juvenile red snapper habitat. Demarcation of essential fish habitat for juvenile red snapper (Lutjanus campechansis) in the Gulf of Mexico is considered critical for effective management of this valuable species. The first goal of this study was to map and describe the geology of this region. The second goal was to attempt to relate variations in geology to juvenile red snapper abundance and distribution. Sidescan mosaics were created for ten polygons, ranging in size …
Restoration Success Of Backfilling Canals In Coastal Louisiana Marshes, Joseph Baustian
Restoration Success Of Backfilling Canals In Coastal Louisiana Marshes, Joseph Baustian
LSU Master's Theses
The need for effective marsh restoration techniques in Louisiana is a pressing issue as the state continues to lose coastal wetlands. Returning spoil banks to canals, known as "backfilling", is an attractive restoration option because it restores marsh, prevents future wetland loss, and is cost effective. The direct conversion of marsh to canals and spoil banks accounted for over 22% of Louisiana's wetland loss from 1930 to 1990, and the indirect losses associated with canal dredging are even larger. The restoration success of 30 canals, backfilled twenty years ago, was examined in this study and compared to restoration success shortly …
Population Dynamics Of Clausocalanus Furcatus (Copepoda, Calanoida) In The Northern Gulf Of Mexico, Hongsheng Bi
Population Dynamics Of Clausocalanus Furcatus (Copepoda, Calanoida) In The Northern Gulf Of Mexico, Hongsheng Bi
LSU Doctoral Dissertations
Copepods are important components of marine ecosystems. Understanding copepod population dynamics can help interpret variations in both primary producers and higher trophic levels. Egg production, stage duration, and stage-specific mortality rates are key parameters describing copepod population dynamics. Estimation of stage-specific mortality is complicated due to a complex life history, patchiness, and sampling biases. This study was undertaken to quantify the population dynamics of the copepod Clausocalanus furcatus in the northern Gulf of Mexico and to assess the utility of available mortality estimation methods in a highly advective environment. Zooplankton samples were taken every 12h from March 18-April 6, and …
Aspects Of The Life History, Ecophysiology, Bioenergetics, And Population Dynamics Of The Cownose Ray, Rhinoptera Bonasus, In The Northern Gulf Of Mexico, Julie Ann Neer
LSU Doctoral Dissertations
The cownose ray, Rhinoptera bonasus, is an elasmobranch commonly observed throughout the Gulf of Mexico. Cownose rays appear to be sensitive to water temperature. I performed laboratory experiments and collected field data to obtain basic life history information, and used the information to configure an individual-based bioenergetics model. The bioenergetics model was coupled to a matrix projection model, and the coupled models were used to predict how warmer and cooler water temperatures, compared to current conditions, would affect the growth and population dynamics of the cownose rays. The life history study determined weight at age, maturity by weight, and fecundity …
Offshore Oil And Gas Platforms As Stepping Stones For Expansion Of Coral Communities: A Molecular Genetic Analysis, Amy D. Atchison
Offshore Oil And Gas Platforms As Stepping Stones For Expansion Of Coral Communities: A Molecular Genetic Analysis, Amy D. Atchison
LSU Master's Theses
The northern Gulf of Mexico (GOM) is one of the most productive oil and gas exploration areas in the world, currently containing approximately 3,800 offshore platforms. These platforms serve as artificial reefs in shallow water, which until their introduction was nearly devoid of shallow hard substrata. The question is raised whether this newly available substrate could help expand coral populations in the GOM. In this study, I examined adult scleractinian corals on oil and gas platforms in the northern GOM, in the vicinity of the Flower Garden Banks (FGB; approximately 180 km SE of Galveston, Texas) and attempted to determine …
Belowground Productivity Of Mangrove Forests In Southwest Florida, Beatriz Eugenia Giraldo Sánchez
Belowground Productivity Of Mangrove Forests In Southwest Florida, Beatriz Eugenia Giraldo Sánchez
LSU Doctoral Dissertations
Studies in belowground dynamics are limited mainly due to the difficulty of studying roots despite wide recognition of its importance. This dissertation focused on methods for analyzing mangrove roots, root responses to phosphorus and flooding, and variation in root production between forest types. Techniques to separate live and dead roots such as colorimetric, fluorescence, buoyancy, and visual assessment were compared. The traditional method of visual assessment combined with root buoyancy was accurate, fast, and applicable to larger samples. Additionally, techniques such as rhizotrons, root ingrowth cores, and root image analysis were useful to study mangrove roots. Root and litter production, …
Detailed Geochronology Of The Mississippi Sound During The Late Holocene, Brian Velardo
Detailed Geochronology Of The Mississippi Sound During The Late Holocene, Brian Velardo
LSU Master's Theses
The Mississippi Sound is a bar-built estuary that parallels the Mississippi Coast. It is bounded on the west by the St. Bernard lobe of the Mississippi River delta, Mobile Bay to the east, and the Gulf Coast barrier islands to the south. Few studies have investigated the late Holocene history of Mississippi Sound. In the present study, historical deposition in the Sound has been investigated using core data collected throughout the western, central, and eastern Mississippi Sound. The sediments within Mississippi Sound compose a complex depositional system that have responded to changes in sea level and hydrodynamics. Two factors that …
Platform Recruited Reef Fish, Phase I: Do Platforms Provide Habitat That Increase The Survival Of Juvenile Reef Fishes?, Lauren Kay Nowling
Platform Recruited Reef Fish, Phase I: Do Platforms Provide Habitat That Increase The Survival Of Juvenile Reef Fishes?, Lauren Kay Nowling
LSU Master's Theses
There are currently over 4000 functioning oil and gas platforms in the northern Gulf of Mexico (Gulf). Platform operations, and their prior drilling operations, produce trace amounts of lead, barium, vanadium, and lanthanum residues that are leached into the surrounding waters and are deposited on the sea floor. These residues have isotopic ratios different from those typical of the Gulf seafloor and can be used as harmless ‘fingerprints’ if they become incorporated into hard-parts or tissues in fishes associated with oil and gas platforms. From 2002 to 2004, 115 red snapper were collected from oil and gas platforms and artificial …
Nutrient Interactions, Plant Productivity, Soil Accretion, And Policy Implications Of Wetland Enhancements In Coastal Louisiana, Christopher Brantley
Nutrient Interactions, Plant Productivity, Soil Accretion, And Policy Implications Of Wetland Enhancements In Coastal Louisiana, Christopher Brantley
LSU Doctoral Dissertations
Ecosystem response, stakeholder interactions, and the policy implications to a wetland assimilation project are reported here for the City of Mandeville, St. Tammany Parish, Louisiana. Between September 1998 and October 2004, input of secondarily treated wastewater effluent was found to have a net positive effect on the downstream wetland receiving basin. The major hydrologic inputs to the system are the effluent, precipitation, and back water flooding from Lake Pontchartrain. Nutrient levels were generally low except in the immediate vicinity of the outfall and removal efficiencies of N and P ranged from 44% to 87% and 25% to 93%, respectively. On …
Spotted Sea Trout (Cynoscion Nebulosus) And Pinfish (Lagodon Rhomboides) Dietary Analysis According To Habitat Type, Micah Russell
Spotted Sea Trout (Cynoscion Nebulosus) And Pinfish (Lagodon Rhomboides) Dietary Analysis According To Habitat Type, Micah Russell
LSU Master's Theses
The diets of a transitory fish (spotted sea trout, Cynoscion nebulosus) and a fish with presumed greater site-fidelity (pinfish, Lagodon rhomboides) were analyzed with respect to habitat. Sampling occurred in Barataria Bay, Louisiana between May 2003 and May 2004. Spotted sea trout were caught using gillnets, and pinfish were caught using baited fish traps. Each gear was used on three habitats: mud bottom, oyster shell, and marsh edge. In addition, sampling for spotted sea trout was repeated at three locations along a salinity gradient. A total of 175 spotted sea trout stomachs and 137 pinfish stomachs were examined. Seventeen prey …
The Establishment, Expansion And Ecosystem Effects Of Phragmites Australis, An Invasive Species In Coastal Louisiana, Lee Ellis Stanton
The Establishment, Expansion And Ecosystem Effects Of Phragmites Australis, An Invasive Species In Coastal Louisiana, Lee Ellis Stanton
LSU Doctoral Dissertations
As biological invasions have become a common phenomenon throughout the world, ecologists have intensified efforts to understand why natural communities are susceptible to invasion. Invading species can cause shifts in community structure that result in irreversible changes to ecosystem function. Phragmites australis has rapidly spread in North American coastal wetlands during the past 50 years and has become a dominant feature in Northern Gulf of Mexico brackish marshes. The rate at which Phragmites is spreading or the mechanisms controlling its establishment in these marshes is unknown. My research objectives were to: (1) determine the spatial and temporal patterns of Phragmites …
The Effects Of Aluminum Concentration On Growth Responses In Six Spartina Alterniflora Genotypes, Daniel Farrell Becker
The Effects Of Aluminum Concentration On Growth Responses In Six Spartina Alterniflora Genotypes, Daniel Farrell Becker
LSU Master's Theses
Elevated soluble aluminum concentrations can adversely affect plant growth. During a drought, wetland soils may experience higher than normal soluble aluminum due to the oxidation of metal sulfides and resulting decreases in pH, which mobilizes metallic cations. Louisiana coastal salt marshes were subject to a record-setting drought in the winter and spring of 2000 which was coincident with the die-off of large expanses of salt marsh, termed " brown marsh ". Spartina alterniflora was the primary plant species affected. However, because some individuals within large areas of die-off survived the brown marsh event, they may have been the more resistant …