Open Access. Powered by Scholars. Published by Universities.®

Oceanography and Atmospheric Sciences and Meteorology Commons™

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

2004

Articles 1 - 15 of 15

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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. …

Go to article

Influence Of The Marsh Edge On The Structure And Trophic Ecology Of The Fish And Macroinvertebrate Community In A Louisiana Estuarine Ecosystem, Guillermo Duque Jan 2004

Influence Of The Marsh Edge On The Structure And Trophic Ecology Of The Fish And Macroinvertebrate Community In A Louisiana Estuarine Ecosystem, Guillermo Duque

LSU Doctoral Dissertations

Habitat degradation of saltmarsh ecosystems reduces the suitability of the marsh as permanent environments for resident species and seasonal nursery grounds for transient fauna. This study was conducted in Terrebonne-Timbalier bays near Cocodrie, Louisiana. Fishes and macroinvertebrates were collected using a drop sampler in marsh-edge and open-water habitat types, in three locations (i.e., pond, channel, and bay), and four seasons (Fall of 2000, Winter of 2000-2001, and Spring and Summer of 2001). The specific objectives of this study were: (1) to determine the difference in composition and structure of fish and macroinvertebrate communities, (2) to establish the food habits of …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

Application Of Disturbance Theory To Assess Impacts Associated With A Three-Dimensional Seismic Survey In A Freshwater Marsh In Southwest Louisiana, Aaron Stuard Bass Jan 2004

Application Of Disturbance Theory To Assess Impacts Associated With A Three-Dimensional Seismic Survey In A Freshwater Marsh In Southwest Louisiana, Aaron Stuard Bass

LSU Doctoral Dissertations

This study examined various practical and theoretical aspects of disturbance in a coastal wetland marsh in southern Louisiana. A literature review approached disturbance ecology from both practical and theoretical perspectives and assessed its applicability to developing broad predictive models. However, specific knowledge of environmental variables, competitive relationships, and the interactive effects of multiple disturbances are required for meaningful usage of these models. The Lacassine National Wildlife Refuge (LNWR) proved to be an ideal laboratory to test various aspects of ecological disturbance theory. I found that the primary disturbances affecting the LNWR have been hurricanes, droughts, water-level manipulations, prescribed burning, oil …

Go to article

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 …

Go to article

Stormwater Diversion As A Potential Coastal Wetland Restoration Method, Jennifer Howard Woods Jan 2004

Stormwater Diversion As A Potential Coastal Wetland Restoration Method, Jennifer Howard Woods

LSU Master's Theses

The Barataria-Terrebonne estuary has been eroding at a rate of up to 103.6 km2 yr-1 for several decades. If the current rate of loss is not reduced, an additional 2,550 km2 of coastal wetlands will be lost by the year 2050. Currently, stormwater in Terrebonne Parish is pumped into canals, ultimately discharging into the Gulf of Mexico. An opportunity exists to use this stormwater for wetland restoration; however, the ecological impacts of stormwater diversions on wetlands are unknown. The objectives of this project were to 1) to investigate the seed banks of a degraded marsh to determine if a viable …

Go to article

Short-Term Evolution Of A Marsh Island System And The Importance Of Cold Front Forcing, Terrebonne Bay, Louisiana, Dana Ann Watzke Jan 2004

Short-Term Evolution Of A Marsh Island System And The Importance Of Cold Front Forcing, Terrebonne Bay, Louisiana, Dana Ann Watzke

LSU Master's Theses

Short-term, wave induced erosion along bay beaches in the northern Gulf of Mexico has been linked to the postfrontal phase of cold front passages. Not until recently has consideration been given to the importance of wave erosion on marshes fringing large bays during the entire cold front event. Two WAVCIS (Wave-Current-Surge-Information System) stations were established on the north and south flank of a small marsh island in Terrebonne Bay, Louisiana, to measure and elucidate the hydrodynamic response to these events. Data from WAVCIS stations, which includes wind speed and direction, air temperature, significant wave height and water level, were collected …

Go to article

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 …

Go to article

Freshwater And Nutrient Inputs To A Mississippi River Deltaic Estuary With River Re-Introduction, Emily Christina Grace Hyfield Jan 2004

Freshwater And Nutrient Inputs To A Mississippi River Deltaic Estuary With River Re-Introduction, Emily Christina Grace Hyfield

LSU Master's Theses

In this study, I quantified freshwater and nutrient inputs in the Breton Sound estuary which is receiving freshwater reintroduction in an effort to restore deteriorating wetlands. Almost all wetlands of the Mississippi deltaic plain are isolated from riverine input due to flood control levees along the Mississippi River. This has altered water and nutrient budgets and is a primary cause of the massive wetland loss in the delta. Maintenance of the delta depends on a healthy, functioning ecosystem which includes riverine input. The Breton Sound estuary is located southeast of New Orleans and until recently was hydrologically isolated from direct …

Go to article