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Louisiana State University

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Articles 301 - 330 of 377

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

A Neural Network Model For Classification Of Coastal Wetlands Vegetation Structure With Moderate Resolution Imaging Spectro-Radiometer (Modis) Data, Evaristo Joseph Liwa Jan 2006

A Neural Network Model For Classification Of Coastal Wetlands Vegetation Structure With Moderate Resolution Imaging Spectro-Radiometer (Modis) Data, Evaristo Joseph Liwa

LSU Doctoral Dissertations

Mapping coastal marshes is an important component in the management of coastal environments. Classification of marshes using remote sensing data has traditionally been performed by employing either parametric supervised classification algorithms or unsupervised classification algorithms. The implementation of these conversional classification methods is based on the underlying distributions concerning the probability density functions (PDF). Neural networks provide a practical approach to this classification because they are essentially non-parametric data transformations that are not restricted by any underlying assumptions. The major objective of this study was to evaluate the ability of neural networks using Moderate Resolution Imaging Spectro-radiometer (MODIS) data to …

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A Community Approach To Identifying Essential Fish Habitat Of Spotted Seatrout, Cynoscion Nebulosus, In Barataria Bay, La, Pamela Sharon Dawn Macrae Jan 2006

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 …

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River, Tidal And Wind Interactions In A Deltaic Estuarine System, Gregg Snedden Jan 2006

River, Tidal And Wind Interactions In A Deltaic Estuarine System, Gregg Snedden

LSU Doctoral Dissertations

The balance between river and marine influences is important in governing landscape sustainability in river deltas. River- and atmospherically driven sea level variability, sediment loading, and estuary-ocean exchange in the Mississippi River delta are examined in this study. Subtidal estuarine sea level variability in the Breton Sound estuary was driven by a combination of remote atmospheric forcing outside the estuary over the continental shelf and controlled river inputs through a gated diversion structure at the estuary head. The highly-frictional deltaic landscape acted as a low-pass filter to coastal fluctuations near the estuary mouth. When substantial quantities river water were discharged …

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Nitrate Reduction And Methane Formation As Influenced By Iron-Centered Intermediate Redox Processes In Rice Soils, Bin Huang Jan 2005

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 …

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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 Jan 2005

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 …

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The Establishment, Expansion And Ecosystem Effects Of Phragmites Australis, An Invasive Species In Coastal Louisiana, Lee Ellis Stanton Jan 2005

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 …

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Offshore Oil And Gas Platforms As Stepping Stones For Expansion Of Coral Communities: A Molecular Genetic Analysis, Amy D. Atchison Jan 2005

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 …

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Effects Of Adding Sediment To A Fresh Water Thin Mat Floating Marsh, Kate Carpenter Jan 2005

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 …

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Platform Recruited Reef Fish, Phase I: Do Platforms Provide Habitat That Increase The Survival Of Juvenile Reef Fishes?, Lauren Kay Nowling Jan 2005

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 …

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Nekton Utilization Of Black Mangrove (Avicennia Germinans) And Smooth Cordgrass (Spartina Alterniflora) Sites In Southwestern Caminada Bay, Louisiana, Melanie Christine Caudill Jan 2005

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 …

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The Effects Of Aluminum Concentration On Growth Responses In Six Spartina Alterniflora Genotypes, Daniel Farrell Becker Jan 2005

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 …

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Benthic Communities In The Northern Gulf Of Mexico Hypoxic Area: Potential Prey For Demersal Fish, Melissa Millman Baustian Jan 2005

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 …

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Geologic Variability And Holocene Sedimentary Record On The Northern Gulf Of Mexico Inner To Mid-Continental Shelf, Triniti A. Dufrene Jan 2005

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 …

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Nutrient Interactions, Plant Productivity, Soil Accretion, And Policy Implications Of Wetland Enhancements In Coastal Louisiana, Christopher Brantley Jan 2005

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 …

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Detailed Geochronology Of The Mississippi Sound During The Late Holocene, Brian Velardo Jan 2005

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 …

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Spotted Sea Trout (Cynoscion Nebulosus) And Pinfish (Lagodon Rhomboides) Dietary Analysis According To Habitat Type, Micah Russell Jan 2005

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 …

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Belowground Productivity Of Mangrove Forests In Southwest Florida, Beatriz Eugenia Giraldo Sánchez Jan 2005

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, …

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Restoration Success Of Backfilling Canals In Coastal Louisiana Marshes, Joseph Baustian Jan 2005

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 …

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Denitrification And Greenhouse Gas Emissions From Cultivated And Wetland Alluvial Soils, Sami Ullah Jan 2005

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 …

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Population Dynamics Of Clausocalanus Furcatus (Copepoda, Calanoida) In The Northern Gulf Of Mexico, Hongsheng Bi Jan 2005

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 …

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Coastal Wetland Subsidence Arising From Local Hydrologic Manipulations, R. Eugene Turner Apr 2004

Coastal Wetland Subsidence Arising From Local Hydrologic Manipulations, R. Eugene Turner

Faculty Publications

Twenty-three estimates of soil subsidence rates arising under the influence of local hydrologic changes from flap-gates, weirs, dikes, and culverts in tidal wetlands were compared to 75 examples of subsidence in drained agricultural wetlands. The induced subsidence rates from these hydrologic modifications in tidal wetlands can continue for more than 100 years, and range between 1.67 to 0.10 cm yr−1 within 1 to 155 years after the hydrologic modifications commence. These subsidence rates are lower than in freshwater wetlands drained for agricultural purposes, decline with age, and are significant in comparison to the rates of global sea level rise or …

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Inorganic Nitrogen Transformations At High Loading Rates In An Oligohaline Estuary, R. Eugene Turner, Q. Dortch, Nancy N. Rabalais Jan 2004

Inorganic Nitrogen Transformations At High Loading Rates In An Oligohaline Estuary, R. Eugene Turner, Q. Dortch, Nancy N. Rabalais

Faculty Publications

A well-defined nitrogen retention and turnover budget was estimated for a shallow oligohaline lake (Lake Pontchartrain, Louisiana, USA). In 1997 a month-long diversion of the Mississippi River filled the Lake with highly concentrated river water (80 µM nitrate) and lowered the salinity to 0 psu within 2 weeks. After the spillway was closed the Lake mixed with estuarine tidal waters and came to equilibrium over 4 months with the riverine, atmospheric and offshore water nitrogen sources. A flushing rate of 1.78% d−1 was estimated by analyzing a plot of ln salinity versus time for the first 120 days after the …

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Suspended Sediment, C, N, P, And Si Yields From The Mississippi River Basin, R. Eugene Turner, Nancy N. Rabalais Jan 2004

Suspended Sediment, C, N, P, And Si Yields From The Mississippi River Basin, R. Eugene Turner, Nancy N. Rabalais

Faculty Publications

The annual loads of C,N,P, silicate, total suspended sediment (mass) and their yields (mass area−1) were estimated for six watersheds of the Mississippi River Basin (MRB) using water quality and water discharge records for 1973 to 1994. The highest load of suspended sediments is from the Missouri watershed (58 mt km2 yr−1), which is also the largest among the six major sub-basins. The Ohio watershed delivers the largest load of water (38%). The Upper Mississippi has the largest total nitrogen load (32%) and yield (1120 kg TN km2 yr−1). The loading of organic carbon, total phosphorus and silicate from the …

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Below-Ground Biomass In Healthy And Impaired Salt Marshes, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee, Thomas A. Oswald Jan 2004

Below-Ground Biomass In Healthy And Impaired Salt Marshes, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee, Thomas A. Oswald

Faculty Publications

Twelve salt marshes in south Louisiana (USA) were classified as either ‘impaired’ or ‘healthy’ before a summer sample collection of above- and below-ground biomass and determination of sediment accretion rates. The above-ground biomass of plant tissues was the same at both impaired and healthy salt marshes and was not a good predictor of marsh health. However, below-ground root biomass in the upper 30 cm was much lower in the impaired marshes compared to the healthy marshes. Compromises to root production apparently occur before there is an obvious consequence to the above-ground biomass, which may quickly collapse before remedial action can …

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Feeding Ecology And Morphometric Analysis Of Paddlefish, Polyodon Spathula, In The Mermentau River, Louisiana, Nicole Adele Smith Jan 2004

Feeding Ecology And Morphometric Analysis Of Paddlefish, Polyodon Spathula, In The Mermentau River, Louisiana, Nicole Adele Smith

LSU Master's Theses

Little is known about the morphometrics and the feeding ecology of paddlefish in Louisiana. I examined the morphometrics and feeding ecology of paddlefish from the Mermentau River, Louisiana from March 2002 to February 2003. Paddlefish were examined morphometrically by taking measurements of eye-fork length (EFL), body cavity length (BCL), girth (G), vent girth (VG), mouth vertical (MTB), mouth horizontal (MSS), and mouth gullet bottom (MGB) to determine which parameters would give a better estimate of weight (W). Regression analysis resulted in a morphometric model of the form: logW = 10.10 + 1.52 (logEFL) + 1.21 (logG) + 0.24 (logVG) (r2 …

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Transport And Deposition Of Fluid Mud Event Layers Along The Western Louisiana Inner Shelf, Kristina Anne Rotondo Jan 2004

Transport And Deposition Of Fluid Mud Event Layers Along The Western Louisiana Inner Shelf, Kristina Anne Rotondo

LSU Master's Theses

The western Louisiana inner shelf along the Chenier Plain coast has experienced fluid mud deposition in response to increased fine sediment supplied by the Atchafalaya River since ~1950’s. The goal of this project is to assess the characteristics comprising the sedimentary strata and stratigraphic architecture that result from mud deposition on the inner shelf. Recent time-series cores collected from the inner shelf along the Chenier plain coast show the region is subject to transient fluid mud deposition, leading to high long-term accumulation rates. Sediment cores were collected in May 2001, March and May 2002 from the inner shelf landward of …

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The Fidelity Of Red Snapper (Lutjanus Campechanus) To Petroleum Platforms And Artificial Reefs In The Northern Gulf Of Mexico, Megan Blythe Peabody Jan 2004

The Fidelity Of Red Snapper (Lutjanus Campechanus) To Petroleum Platforms And Artificial Reefs In The Northern Gulf Of Mexico, Megan Blythe Peabody

LSU Master's Theses

The habitat value of petroleum platforms for red snapper, Lutjanus campechanus, is poorly understood. However, it is widely recognized by both scientists and fishermen that the presence of platforms in the northern Gulf of Mexico (GOM) has affected the distribution of red snapper by the addition of hard substrate habitat. I evaluated the habitat value of standing and toppled platforms by monitoring the fidelity of red snapper to these structures with acoustic telemetry. In May 2003, 125 red snapper were captured with hook and line at several platforms in a 35-km2 portion of the South Timbalier oil and gas lease …

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The Effects Of Nutrient Enrichment On The Decomposition Of Belowground Organic Matter In A Sagittaria Lancifolia - Dominated Oligohaline Marsh, Kristen Raye Laursen Jan 2004

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 …

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Quantification Of Marine Sediment Properties From Planar And Volumetric Pore Geometries, Allen Hagerman Reed Jan 2004

Quantification Of Marine Sediment Properties From Planar And Volumetric Pore Geometries, Allen Hagerman Reed

LSU Doctoral Dissertations

Pore geometry and topology are important determinants of sediment physical properties, such as porosity and permeability. They also influence processes that occur in the sediment, such as acoustic propagation, attenuation, and dispersion, single- and multi-phase fluid flow, and hydrodynamic dispersion. This study uses images to evaluate pore geometry and topology of ooid (subspherical particles) and siliclastic (angular quartz) sand that was collected from the marine environment south of Bimni Bahamas and Ft. Walton Beach, FL, respectively. Image analysis techniques and predictive tools enable insight into the relationships among sediment pore geometry, topology, and physical properties for these differently shaped sands. …

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Leaf Litter Processing By Macrodetritivores In Natural And Restored Neotropical Mangrove Forests, Gary Eugene Raulerson Jan 2004

Leaf Litter Processing By Macrodetritivores In Natural And Restored Neotropical Mangrove Forests, Gary Eugene Raulerson

LSU Doctoral Dissertations

Knowledge of mangrove litter dynamics is crucial to an understanding of the energetic links between mangrove ecosystems and nearby estuaries and coastal waters. Previous research into the role played by macrodetritivores in Neotropical mangrove litter processing has been contradictory. This study used leaf tethering to examine the effects of macrodetritivores on initial rates of mangrove litter degradation in South Florida, USA. Leaf litter dynamics experiments were run in both natural and restored mangrove forests to assess functionality of the restoration projects. Although less important than in some other parts of the world (e.g., the Indo-Pacific), macrodetritivores played a significant role …

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