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Articles 121 - 150 of 377

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Accumulation Of Blue Carbon And Nutrients In An Active Delta Of Coastal Louisiana, Madeline Leblanc Apr 2018

Accumulation Of Blue Carbon And Nutrients In An Active Delta Of Coastal Louisiana, Madeline Leblanc

Honors Capstones

No abstract provided.


Influence Of Black Mangrove Expansion On Salt Marsh Faunal Communities Of Eastern Coastal Louisiana, Christina Powell Mar 2018

Influence Of Black Mangrove Expansion On Salt Marsh Faunal Communities Of Eastern Coastal Louisiana, Christina Powell

LSU Master's Theses

The salt marshes along the Gulf of Mexico provide a critical habitat for many species, but their spatial distribution is changing, because Avicennia germinans (black mangroves) are expanding due to warmer winters. Currently, little is known about how A. germinans are used as habitat providing food and refuge for aquatic fauna. Therefore, the overall goal of this study was to determine how A.germinans expansion into the Spartina alterniflora (smooth cordgrass) marshes of Louisiana’s Mississippi River delta plain affects salt marsh-dependent organisms. This study analyzed three habitat types: Spartina-dominated, Avicennia-dominated, and a mix of the two, focusing on habitat use and …


Numerical Experiment Of Sediment Dynamics Over A Dredged Pit On The Louisiana Shelf, Nazanin Chaichitehrani Mar 2018

Numerical Experiment Of Sediment Dynamics Over A Dredged Pit On The Louisiana Shelf, Nazanin Chaichitehrani

LSU Doctoral Dissertations

Sediment transport over Sandy Point dredge pit in the northern Gulf of Mexico was examined using field measurements and a finely resolved numerical model. Delft3D model with well-vetted computational grid and input parameters was used. Numerical experiments were performed to examine the effect of wind-generated waves, wind-driven currents and their interaction on sediment dynamics in our study area during a cold front in November 2014 and fair-weather conditions between July and August of 2015. Sediment dispersal from the lower Mississippi River, sediment resuspension, transport and deposition with high spatial and temporal resolution were simulated. A reliable satellite-derived near-surface suspended particulate …


The Tensile Root Strength Of Emergent Coastal Macrophytes, Lauris Olivia Hollis Mar 2018

The Tensile Root Strength Of Emergent Coastal Macrophytes, Lauris Olivia Hollis

LSU Doctoral Dissertations

Spartina patens is a dominant emergent macrophyte in fresh, intermediate, and brackish marshes along the Atlantic and Gulf coasts of United States where its biomechanical properties are a key component of wetland health and resilience. Its root biomass and tensile root strength are essential for anchorage, erosion protection, and are important determinants of soil strength. Nutrients and the herbicide atrazine are suspected of negatively impacting this wetland plant and others. The objectives of this study were to: 1) ascertain the tensile root strength of five emergent coastal macrophytes in coastal estuaries, and 2) test the effects of nutrient addition, atrazine …


Natural And Anthropogenic Impacts On Sediment Dynamics And Preservation In Contrasting Mississippi Deltaic Coastal Environments, Jiaze Wang Feb 2018

Natural And Anthropogenic Impacts On Sediment Dynamics And Preservation In Contrasting Mississippi Deltaic Coastal Environments, Jiaze Wang

LSU Doctoral Dissertations

Deltas worldwide share the same sinking problem in face of pressure from natural and anthropogenic activities. Many restoration strategies are being planned or have been implemented in the coasts around the world. However, many conventional hard structure constructions are energy-intensive. There are also associated uncertainties and limitations on the effectiveness and sustainability of these restoration plans. Soft or ecological engineering strategies normally take advantage of or mimic the coastal system self-response and feedbacks to natural and anthropogenic activities. The successful implementation of soft strategies relies on process-based studies on the change of complex coastal system. In addition, post-implementation monitoring work …


Evolution Of The Maximum Upper Level Divergence Field In Gulf-Atlantic Tropical Cyclogenesis, Sara A. Ates Jan 2018

Evolution Of The Maximum Upper Level Divergence Field In Gulf-Atlantic Tropical Cyclogenesis, Sara A. Ates

LSU Master's Theses

Upper-level (horizontal) divergence (ULD) is an important variable in tropical weather systems. As part of the circulation within a tropical cyclone (TC), it carries air in the upper troposphere away from the center of circulation (COC). To date, most research assumes the 200 hPa pressure level (approximately 12 km, varying with latitude and time of year) as the height for maximum ULD in a TC, possibly because weather observation at the 200 hPa level by radiosonde have remained mandatory for aviation purposes. The more recent availability of gridded, high-spatial-resolution, global “reanalysis” data at multiple levels, along with improvements in spatial …


Dinoflagellate Cysts Track Eutrophication In The Northern Gulf Of Mexico, Andrea M. Price, Melissa M. Baustian, R. Eugene Turner, Nancy N. Rabalais, Gail L. Chmura Dec 2017

Dinoflagellate Cysts Track Eutrophication In The Northern Gulf Of Mexico, Andrea M. Price, Melissa M. Baustian, R. Eugene Turner, Nancy N. Rabalais, Gail L. Chmura

Faculty Publications

We examined organic-walled dinoflagellate cysts from one 210Pb-dated sediment core and 39 surface sediment samples from the northern Gulf of Mexico to determine the relationship between nutrient enrichment and cyst assemblages in this region characterized by oxygen deficiency. The core spans from 1962 to 1997 and its sampling location is directly influenced by the Mississippi River plume. Surface sediments were collected in 2006, 2007, 2008, and 2014 and represent approximately 1 to 4 years of accumulation. A total of 57 cyst taxa were recorded, and four heterotrophic taxa in particular were found to increase in the top section (1986–1997) of …


Paleoenvironmental Reconstruction Using Coral Microatolls (Sp. Siderastrea Siderea) From The Gulf Of Gonâve, Haiti, Gilman Reno Ouellette Jr. Nov 2017

Paleoenvironmental Reconstruction Using Coral Microatolls (Sp. Siderastrea Siderea) From The Gulf Of Gonâve, Haiti, Gilman Reno Ouellette Jr.

LSU Doctoral Dissertations

Natural and anthropogenic climate changes present unique and serious risks to society. In order to plan and implement adaptation and mitigation strategies successfully, regional manifestations of broad-scale climate changes must be understood robustly. The Caribbean region contains part of the Western Hemisphere Warm Pool (WHWP), a major sea surface temperature (SST) feature that plays a key role in North Atlantic climate. Climate variability in the Caribbean is captured poorly by climate models, due in part to a lack of continuous, multidecadal instrumental climate records from the region. I explored three research questions in this dissertation: Does non-systematic bias exist in …


How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution And Infilling Processes, Patrick Robichaux Nov 2017

How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution And Infilling Processes, Patrick Robichaux

LSU Master's Theses

As coastal environments become more susceptible to land loss through accelerating sea level rise and subsidence, new restoration methods harnessing borrowed sediment are more valuable than ever. Mud-capped dredge pits (MCDPs) are a relatively new source of restoration-quality sediment that has only recently been utilized for beach and barrier island restorations in Louisiana. Because MCDPs have been in use for less than two decades in only a handful sites, little is understood about their evolution over decadal timescales. To improve our understanding of MCDPs after they are dredged, we have conducted a suite of geophysical surveys including bathymetry, sidescan sonar, …


Effects Of Increased Sedimentation On Carbon Accumulation Of Salt Marsh Benthic Biofilms, Abbey Hotard Apr 2017

Effects Of Increased Sedimentation On Carbon Accumulation Of Salt Marsh Benthic Biofilms, Abbey Hotard

Honors Capstones

No abstract provided.


Influence Of Nutrient Availability And Sediment Supply On Productivity Of Spartina Patens, Shannon Matzke Apr 2017

Influence Of Nutrient Availability And Sediment Supply On Productivity Of Spartina Patens, Shannon Matzke

Honors Capstones

No abstract provided.


Development And Application Of A Modis Inorganic Sediment Model During The 2016 Mississippi River Diversion In Lake Pontchartrain, Louisiana, Robert Lee Iles Iv Jan 2017

Development And Application Of A Modis Inorganic Sediment Model During The 2016 Mississippi River Diversion In Lake Pontchartrain, Louisiana, Robert Lee Iles Iv

LSU Master's Theses

The Bonnet Carré Spillway (BCS) is a Mississippi River diversion located on the southwestern coastline of Lake Pontchartrain in Louisiana. The discharge of potentially high amounts of Mississippi River nutrients and sediments during BCS diversion events has a noted ecological impact on the Lake Pontchartrain estuary. Projected river flooding prompted the opening of the Spillway from 10 January to 1 February 2016. MODIS satellite images were aerosol-corrected and then compared to in-situ measurements of inorganic sediment concentration (ISC) to derive a predictive algorithm for estimating ISC (in mg L^-1) in Lake Pontchartrain for satellite images in January and February. The …


Differential Responses Of Soil Greenhouse Gas Production And Denitrification To Salinity Alterations Along A Wetland Salinity Gradient, Natalie Ceresnak Jan 2017

Differential Responses Of Soil Greenhouse Gas Production And Denitrification To Salinity Alterations Along A Wetland Salinity Gradient, Natalie Ceresnak

LSU Master's Theses

Coastal wetlands provide several valuable services, such as carbon (C) storage and nitrogen (N) removal. Although wetlands serve as net C sinks, wetland soils release greenhouse gases (GHGs) including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Wetlands can buffer the influx of nitrate (NO3-) by transforming it into gaseous N (N2O, N2) through denitrification microbial pathway. Salinity is a regulator of soil biogeochemistry and long- (e.g. saltwater intrusion) and short-term (e.g. storm surges, river diversions) exposures may affect soil GHG production and denitrification. In this study, soil GHG production and denitrification enzyme activity (DEA) rates were examined over …


Modeling The Influence Of Energy And Climate Megatrends On Future Costs And Benefits Of Marsh Creation In The Mississippi Delta, Adrian R. H. Wiegman Jan 2017

Modeling The Influence Of Energy And Climate Megatrends On Future Costs And Benefits Of Marsh Creation In The Mississippi Delta, Adrian R. H. Wiegman

LSU Master's Theses

Over 25% of Mississippi delta (MRDP) wetlands were lost over the past century. There is currently a major effort to restore the MRDP focused on a 50-year time horizon, a period during which the energy system and climate will change dramatically. I modeled hydraulic dredging to sustain marsh from 2016-2066 and 2016-2100 under a range of scenarios for sea level rise, energy price, and management regimes. A marsh elevation model was calibrated to data from MRDP marshes. I developed a model to simulate dredging costs based on the price of crude oil and a project efficiency factor. Crude oil prices …


Sediment Transport And Slope Stability In The Northern Gulf Of Mexico, Jeffrey Blake Obelcz Jan 2017

Sediment Transport And Slope Stability In The Northern Gulf Of Mexico, Jeffrey Blake Obelcz

LSU Doctoral Dissertations

Sediment transport and slope stability are fundamental organizing agents of the geological record. These processes have been extensively studied along the northern margin of the Gulf of Mexico basin for both basic and applied purposes, but our knowledge of them is limited by the spatial and temporal sampling capabilities of traditional geologic oceanographic surveying tools such as coring, single-beam echosounders, and sidescan sonar. This dissertation seeks to update the state of knowledge regarding northern Gulf of Mexico sediment transport and slope stability from annual to millennial timescales, primarily using relatively high-resolution acoustic geophysical tools such as swath bathymetric echosounders and …


The Changshu Declaration On Wetlands, R. Eugene Turner, Jos T. A. Verhoeven, Ania Grobicki, Jenny Davis, Shuqing An Sep 2016

The Changshu Declaration On Wetlands, R. Eugene Turner, Jos T. A. Verhoeven, Ania Grobicki, Jenny Davis, Shuqing An

Faculty Publications

No abstract provided.


Influence Of The Mississippi River On Pseudo-Nitzschia Spp. Abundance And Toxicity In Louisiana Coastal Waters, Sibel Bargu, Melissa M. Baustian, Nancy N. Rabalais, Ross Del Rio, Benjamin Von Korff, R. Eugene Turner Mar 2016

Influence Of The Mississippi River On Pseudo-Nitzschia Spp. Abundance And Toxicity In Louisiana Coastal Waters, Sibel Bargu, Melissa M. Baustian, Nancy N. Rabalais, Ross Del Rio, Benjamin Von Korff, R. Eugene Turner

Faculty Publications

The presence of domoic acid (DA) toxin from multiple species of Pseudo-nitzschia is a concern in the highly productive food webs of the northern 1,* 2,3 2 1 1,4 1 1 2 3 4 Gulf of Mexico. We documented the Pseudo-­nitzschia presence, abundance, blooms, and toxicity over 3 years along a transect ∼100 km west of the Mississippi River Delta on the continental shelf. Pseudo-nitzschia were present throughout the year and occurred in high abundances (>10 cells l ) in the early spring months during high Mississippi River (MSR) flow (∼20,000 m s ) but were most abundant ( …


Size-Dependent Top-Down Control On Phytoplankton Growth By Microzooplankton In Eutrophic Lakes, Wai Hing Wong, Nancy N. Rabalais, R. Eugene Turner Jan 2016

Size-Dependent Top-Down Control On Phytoplankton Growth By Microzooplankton In Eutrophic Lakes, Wai Hing Wong, Nancy N. Rabalais, R. Eugene Turner

Faculty Publications

We hypothesized that the grazing on phytoplankton by the microzooplankton community is size-dependent and, therefore, the top-down control on phytoplankton by microzooplankton community could be one possible mechanism explaining why small phytoplankton become less abundant than large phytoplankton in eutrophic waters. We tested this hypothesis using the dilution method to measure microzooplankton grazing rates and phytoplankton growth rates in the eutrophic waters of the Barataria estuary, southeastern Louisiana. Microzooplankton grazing rates on the slower growing, small phytoplankton (\5 lm) were higher than on the large phytoplankton ([20 lm) which had relatively faster growth rates. The proportional loss of the small, …


The Effect Of Restoration On Nitrate Reduction And Biogeochemical Functioning In Louisiana Wetlands: Bottomland Hardwood Forests And Deltaic Sediments, Nia R. Hurst Jan 2016

The Effect Of Restoration On Nitrate Reduction And Biogeochemical Functioning In Louisiana Wetlands: Bottomland Hardwood Forests And Deltaic Sediments, Nia R. Hurst

LSU Master's Theses

Nitrogen loading in the Mississippi River from increased N fertilization of agricultural land helps to trigger an area of hypoxic water in the northern Gulf of Mexico (GOM) every summer. Louisiana wetlands can play a vital role in removing nitrate from river waters prior to discharge in the GOM. However, Louisiana’s wetlands have experienced significant losses in recent years. Efforts to restore wetlands include reconnecting floodplain wetlands to rivers and utilizing river diversions to re-introduce sediment to coastal wetlands. Increasing wetland connection to rivers can reduce water nitrate by expanding opportunities for nitrate reduction. I examined soil physicochemical properties, microbial …


Everglades Mangrove Forest Response To Large-Scale Disturbance: Long-Term Assessment Of Structural And Functional Properties, Tess Marie Danielson Jan 2016

Everglades Mangrove Forest Response To Large-Scale Disturbance: Long-Term Assessment Of Structural And Functional Properties, Tess Marie Danielson

LSU Master's Theses

The impact (i.e., defoliation and mortality) associated with large-scale natural disturbance events is capable of significantly altering ecosystem structure (e.g., biomass) and function (e.g., productivity) in mangrove wetlands. These pulsing events provide an opportunity to assess ecosystem resilience (i.e., recovery to pre-disturbance conditions) by evaluating the immediate and long-term ecosystem response trajectory (i.e., disturbance magnitude, recovery time). I hypothesized that 1) there are specific properties of disturbance that can be characterized and fit to a general forest disturbance model, and that 2) a mangrove forest recovery trajectory (i.e. recovery duration and rate) is dependent on the disturbance magnitude and initial …


Simulating Behavioral Microcystin Impairment In Fish, Nicholas Richard Keeney Jan 2016

Simulating Behavioral Microcystin Impairment In Fish, Nicholas Richard Keeney

LSU Master's Theses

Fish experiencing blooms of the cyanobacteria genera Microcystis and Anabaena acquire microcystin and saxitoxin through ingestion of contaminated food and absorption of dissolved toxin. Even low chronic doses induce sensory and motor impairment—the impact of which is unquantified in wild populations. Here, I introduce Lagrangian particle models for cyanobacteria and fish which test the hypotheses that impairment symptoms suppress movement and growth. This is implemented within the Finite-Volume Coastal Ocean Model (FVCOM). Cyanobacteria particles move vertically according to mixing and buoyancy (a function of cellular reservoirs). Fish navigate the horizontal domain, foraging in high growth areas, and fleeing when toxin …


A Contemporary Approach To A Classic Model: Exploring The Influence Of Local Interactions And Disturbance On Mangrove Forest Dynamics With A Spatially-Explicit Version Of Forman, Kieley Shannon Hurff Jan 2016

A Contemporary Approach To A Classic Model: Exploring The Influence Of Local Interactions And Disturbance On Mangrove Forest Dynamics With A Spatially-Explicit Version Of Forman, Kieley Shannon Hurff

LSU Master's Theses

The mangrove forest gap dynamic model, FORMAN, was the first individual-based model (IBM) to simulate the long-term successional dynamics of three Caribbean mangrove species, Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle. Assumptions under the spatially implicit approach of gap dynamic models limit their application to small-scale simulations. An expanded, spatially-explicit version of FORMAN was developed to allow for simulations of larger spatial grids, through the inclusion of localized soil conditions and neighborhood-based light resource competition. This expanded model was used to investigate the influence of localized interactions and disturbances of varying size on forest dynamics. A data-model comparison using field …


Investigating Species And Population Level Foraging Variation And Individual Specialization In Pygoscelis Penguins Using Stable Isotope Analysis, Rachael W. Herman Jan 2016

Investigating Species And Population Level Foraging Variation And Individual Specialization In Pygoscelis Penguins Using Stable Isotope Analysis, Rachael W. Herman

LSU Master's Theses

Gentoo Penguins (Pygoscelis papua) are known to be generalist foragers, while Adélie (P. adeliae) and Chinstrap (P. Antarctica) tend to specialize on krill within the Western Antarctic Peninsula and South Shetland Islands, particularly during the breeding season. However, little is known on temporal consistency in diet and foraging habitat of these species, particularly at the individual level. We used stable isotope analysis (SIA) of blood and feathers to evaluate seasonal and individual foraging consistency within Adélie, Chinstrap and Gentoo Penguins breeding in the South Shetland Islands, as well as among three Gentoo Penguins’ populations in the Western Antarctic Peninsula and …


Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly Jan 2016

Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly

LSU Master's Theses

A distinctive feature of coastal Louisiana is the unrivaled network of oil and gas installations (platforms) extending from inshore waters to the deep Gulf of Mexico. Since 2007 there has been a 38% reduction in platform numbers with the highest removal rates occurring in shallow (< 18 m) nearshore waters. Many fishes and invertebrates are attracted to platforms, presenting a unique opportunity to study detailed species-specific responses to the river-influenced hydrographic characteristics of Louisiana’s nearshore zone (5–25 km water depth). Prior studies of fishes around platforms focused on a few relatively large platforms in water depths ≥ 18 m. However, about one-third of all platforms are small, unmanned and non-drilling platforms located in waters < 18 m depth. Paired video and hydrographic data were collected at 150 small platforms in < 18 m water depth during the summers of 2013–2014. Fifty-four species of fishes were associated with small platforms. The assemblage(s) included juveniles of 29 species, indicating the importance of nearshore platforms as diverse nursery habitat. The coastal zone was divided into three regions based on broad-scale interactions between freshwater input and bathymetry driving major distinctions in interregional hydrography and fish assemblages. Co-occurring within this expansive artificial reef network is the second largest hypoxic area (dissolved oxygen (DO) < 2.0 mg l−1) on Earth. Platforms offer reef-like habitat features in the upper water column that may offer refugia for some reef-associated species during hypoxic events. Significant intraregional differences in physicochemical features were related to the presence of hypoxia (defined as DO < 50% saturation), as well as the distribution of sandy shoals. Eleven species accounted for most of the assemblage dissimilarities, composing ~93% of fishes observed. Habitat suitability indices for these 11 species provided information about habitat selection across horizontal and vertical physicochemical gradients throughout the coastal zone, and within hypoxic and well-oxygenated stratified water columns. East Bay, near the outlet of the Mississippi River, exhibited less hypoxia and a distinct fauna that included four adult goliath grouper (Epinephelus itajara). This endangered fish was observed during spawning season (summer), suggesting that East Bay might support a spawning aggregation.


Comparison Of Group Size, Abundance Estimates And Movement Patterns Of Common Bottlenose Dolphins (Tursiops Truncatus) In Mississippi Sound, Mississippi, Carrie Sinclair Jan 2016

Comparison Of Group Size, Abundance Estimates And Movement Patterns Of Common Bottlenose Dolphins (Tursiops Truncatus) In Mississippi Sound, Mississippi, Carrie Sinclair

LSU Master's Theses

Common bottlenose dolphins (Tursiops truncatus; dolphins) inhabiting Mississippi Sound (MSS) in the north-central Gulf of Mexico (GMx) are considered a part of a single stock of dolphins that includes Bay Boudreau and Lake Borgne by the National Marine Fisheries Service (NMFS). MSS is bounded by the mainland (north) and several barrier islands (south). Dolphins inhabiting coastal waters directly south of the barrier islands constitute part of the Northern Coastal Stock. Abundance in MSS has been reported to fluctuate seasonally, with higher abundances of dolphins estimated in summer versus winter. Analysis of covariance was used to compare previous abundance estimates. Results …


Characterization And Modeling Of Sediment Settling, Consolidation And Suspension To Optimize The Retention Rate Of Sediment Diversions For Coastal Restoration, Xiaoyu Sha Jan 2016

Characterization And Modeling Of Sediment Settling, Consolidation And Suspension To Optimize The Retention Rate Of Sediment Diversions For Coastal Restoration, Xiaoyu Sha

LSU Master's Theses

Many research efforts have been made to the Mississippi coastal restoration, but long-term rheological and sedimentological experiments for sediment erosion, deposition and consolidation in diversion receiving basins are still lacking. Push cores and sediment samples were collected from West Bay, a semi-enclosed bay located on the Mississippi River Delta, and Big Mar pond, a receiving basin of the Caernarvon freshwater diversion from the Mississippi River, Louisiana. A dual-core Gust Erosion Microcosm System was used to measure time-series (0.5, 1, 2, 3, 4, 5, and 6-month after initial settling) erodibility at seven shear stress regimes (0.01-0.60 Pa) using experimental cores prepared …


The Effect Of Artificial Light On The Community Structure And Distribution Of Reef-Associated Fishes At Oil And Gas Platforms In The Northern Gulf Of Mexico, Victoria Anne Barker Jan 2016

The Effect Of Artificial Light On The Community Structure And Distribution Of Reef-Associated Fishes At Oil And Gas Platforms In The Northern Gulf Of Mexico, Victoria Anne Barker

LSU Master's Theses

The northern Gulf of Mexico (GOM) contains approximately 2,500 oil and gas platforms, resulting in one of the largest de facto artificial reef systems in the world. As of 2013, 1,227 additional structures had ceased to produce oil and gas and have been decommissioned and removed. While active platforms are lit by high-pressure mercury vapor lights, inactive platforms are only minimally lit for navigation. The positively phototaxic behavior of many fish species causes lit oil platforms to act as fish attraction devices, especially at night. Though a variety of fish species have been reported near these structures, changes in fish …


Feeding Ecology Of Red Snapper And Greater Amberjack At Standing Platforms In The Northern Gulf Of Mexico: Disentangling The Effects Of Artificial Light, Kristin Leanne Foss Jan 2016

Feeding Ecology Of Red Snapper And Greater Amberjack At Standing Platforms In The Northern Gulf Of Mexico: Disentangling The Effects Of Artificial Light, Kristin Leanne Foss

LSU Master's Theses

Approximately 2,300 petroleum platforms are currently operating in the Gulf of Mexico (GOM), and are estimated to provide an additional 4 to 12 km2 of artificial reef habitat. The ecological role of platforms has often been overlooked and little is known about the effect of artificial light from the active platforms on surrounding fish communities. This is the first study to address the potential impacts of artificial light on the trophic ecology of fish communities surrounding offshore platforms through gut content (GCA) and stable isotope (SIA) analyses. Red snapper (Lutjanus campechanus) were collected quarterly from February 2014 to November 2015 …


Coastal Ecosystem Resiliency After Major Disturbances, Giovanna Mcclenachan Jan 2016

Coastal Ecosystem Resiliency After Major Disturbances, Giovanna Mcclenachan

LSU Doctoral Dissertations

Disturbances are a common occurrence in coastal ecosystems and can provide opportunity for adaptation and renewal in healthy systems; hurricanes bring mineral accretion to a marsh, floods provide a pulse of freshwater and nutrients to estuaries, and fires increase species diversity and abundance in forests. Humans, however, have depleted the resiliency of many coastal systems via top down and bottom up mechanisms, leaving these ecosystems more vulnerable to both natural and anthropogenic disturbances. Louisiana’s wetlands have been modified for centuries via canals, levees, agricultural impoundments, etc., leading to a decreased resiliency to land loss. The Deepwater Horizon (DWH) oil spill …


Dynamics Of Land Building And Ecological Succession In A Prograding Deltaic Floodplain, Wax Lake Delta, La, Usa, Azure Elizabeth Bevington Jan 2016

Dynamics Of Land Building And Ecological Succession In A Prograding Deltaic Floodplain, Wax Lake Delta, La, Usa, Azure Elizabeth Bevington

LSU Doctoral Dissertations

Deltas are globally important locations of diverse ecosystems, human settlement and economic activity that are threatened by reduced sediment delivery, accelerated sea level rise, and subsidence. In this dissertation I investigated a number of aspects of the ecosystem development over time within an actively prograding river dominated delta along the northern Gulf of Mexico coast. I outlined a conceptual model of deltaic floodplain wetland establishment and succession focused on the vegetated deltaic floodplain ecosystem, which includes subtidal, intertidal and supratidal zones. This was used to guide the experimental design and statistically driven hypothesis testing in order to ascertain the validity …