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Full-Text Articles in Physical Sciences and Mathematics
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 …
Incorporating Science-Based Approaches Into The Rapid Assessment Of Wetlands And Streams : Validation, Restoration Trajectory, And Method Development, Jacob Franklin Berkowitz
Incorporating Science-Based Approaches Into The Rapid Assessment Of Wetlands And Streams : Validation, Restoration Trajectory, And Method Development, Jacob Franklin Berkowitz
LSU Doctoral Dissertations
Human alterations within wetlands and streams have resulted in a decrease in ecological functions and associated benefits to society. The scientific literature highlights the functional benefits provided by ecosystems including flood protection, nutrient cycling, and habitat maintenance. Additionally, legislation and regulatory policy require mitigation and restoration as compensation for declines in ecological functions. As a result, the need for practical, repeatable, and technically sound ecosystem assessment methods remains essential to natural resource management. However, few studies determine the validity of rapid assessment approaches by applying quantitative parameters, especially with respect to biogeochemical functions. We assessed biogeochemical functions applied to restored …
The Effects Of A Freshwater Diversion Of Nekton Species Biomass Distributions, Food Web Pathways, And Community Structure In A Louisiana Estuary, Kim De Mutsert
The Effects Of A Freshwater Diversion Of Nekton Species Biomass Distributions, Food Web Pathways, And Community Structure In A Louisiana Estuary, Kim De Mutsert
LSU Doctoral Dissertations
A current method to restore Louisiana’s estuaries includes reintroducing freshwater and sediments to wetlands that are hydrologically isolated from the Mississippi River due to the construction of levees. In this dissertation, I examined effects of the second largest freshwater diversion in Louisiana, the Caernarvon Freshwater Diversion (CFD), on estuarine nekton in Breton Sound. Before focusing on Breton Sound, I examined the status of nekton communities in the northern Gulf of Mexico (GOM), and Louisiana wetlands in particular, using the mean trophic level index (MTLI). I demonstrated that commercial targeting caused the previously reported low and declining MTLI from the GOM. …
Barrier Island Migration Over A Consolidating Substrate, Julie Dean Rosati
Barrier Island Migration Over A Consolidating Substrate, Julie Dean Rosati
LSU Doctoral Dissertations
Barrier islands that overlie a compressible substrate load and consolidate the underlying subsurface. Through time, the elevation and aerial extent of these islands are reduced, making them more susceptible to inundation and overwash. Sand washed over the island and onto back-barrier marsh or into the bay or estuary begins the consolidation process on a previously non-loaded substrate, with time-dependent consolidation a function of the magnitude of the load, duration of load, and characteristics of the substrate. The result is an increase in the overwash, migration, breaching, and segmentation of these islands. This research determined the degree to which consolidation affects …
Remediating Impacts Of Global Climate Change-Induced Submergence On Salt Marsh Ecosystem Functions, Camille Lafosse Stagg
Remediating Impacts Of Global Climate Change-Induced Submergence On Salt Marsh Ecosystem Functions, Camille Lafosse Stagg
LSU Doctoral Dissertations
Impacts of global climate change, such as sea level rise and severe drought, have altered the hydrology of coastal salt marshes resulting in submergence and subsequent degradation of ecosystem function. A potential method of rehabilitating these systems is the addition of sediment-slurries to increase the elevation of the marsh surface, thus ameliorating the effects of excessive inundation. Although this technique is growing in popularity, the successful restoration of ecological function after sediment addition has received little attention. The purpose of this research was to determine if sediment subsidized salt marshes are functionally equivalent to natural marshes and whether salt marshes …
Predicting Water Quality Effects On Bay Anchovy (Anchoa Mitchilli) Growth And Production In Chesapeake Bay: Linking Water Quality And Individual-Based Fish Models, Aaron Thomas Adamack
Predicting Water Quality Effects On Bay Anchovy (Anchoa Mitchilli) Growth And Production In Chesapeake Bay: Linking Water Quality And Individual-Based Fish Models, Aaron Thomas Adamack
LSU Doctoral Dissertations
Water quality in the Chesapeake Bay and the Patuxent River has decreased since the 1950s due to an increase in nutrient loadings. Increased nutrient loads have caused an increase in the extent and duration of hypoxic conditions. Restoration via large-scale reductions in nutrient loadings is now underway. How reducing nutrient loadings will affect water quality is well predicted; however the effect on fish is generally unknown as most water quality models do not include trophic levels higher than zooplankton. I combined two water quality models with bay anchovy models (Anchoa mitchilli) to examine the effects of changes in nutrient loadings …
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 …
Below-Ground Biomass In Healthy And Impaired Salt Marshes, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee, Thomas A. Oswald
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 …