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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Investigating Gulf Coast Aquifer System: Stratigraphy Reconstruction, Inverse Modeling, And Groundwater Stress Assessment, Shuo Yang
LSU Doctoral Dissertations
The Mississippi Embayment aquifer system (MEAS) and the Coastal Lowlands aquifer system (CLAS) provide substantial groundwater resources for human activities in the U.S. Gulf Coastal Plain. However, the overexploitation has led to groundwater depletion in the MEAS and the CLAS, threatening sustainable groundwater use. Such concern highlights the crucial need for an advanced understanding of stratigraphy and groundwater in these aquifer systems, which is essential for effective regional groundwater management. This dissertation presents a comprehensive investigation of MEAS and CLAS in the Louisiana and southwestern Mississippi region, encompassing three fundamental dimensions: stratigraphy reconstruction, groundwater modeling, and groundwater stress assessments. A …
Physical And Biological Factors Controlling The Fate Of Nitrate In A Louisiana Coastal Deltaic Floodplain, Alexandra Christensen
Physical And Biological Factors Controlling The Fate Of Nitrate In A Louisiana Coastal Deltaic Floodplain, Alexandra Christensen
LSU Doctoral Dissertations
The Mississippi River Delta is threatened by a growing pressure to support large human populations in the United States both with food production, navigation systems, and urban development in the Mississippi River Basin. Nitrate-nitrogen load in the Mississippi River, up to 100 Tg N yr-1 from agricultural and urban runoff, leads to phytoplankton blooms and hypoxia across the Louisiana continental shelf, creating dead zones of low dissolved oxygen threatening a significant commercial fishery. Along the coast and river corridors, floodplain ecosystems have the capacity to retain and remove nitrate. This dissertation explores the role of productive, actively growing coastal …
Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor
Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor
LSU Doctoral Dissertations
Research focused on three areas of karst hydrogeology and sediment transport that have been poorly studied in the past: the role of particulate inorganic carbon transport in calculating carbon sink rates in karst; rapid changes in surface vs. subsurface sediment mixing in karst conduits; and comparison of landscape denudation calculations using dissolved carbonate load vs. total dissolved/sediment load. Carbonate bedrock weathering is a significant component of the atmospheric carbon sink. Particulate inorganic carbon (PIC) in bed and suspended sediment load of karst waters is frequently dismissed as insignificant for calculating denudation and carbon transport/sink rates, but PIC flux has not …
The Effects Of Hydrologic Modifications On Floodplain Forest Tree Recruitment And Growth In The Mississippi River Alluvial Valley, Usa, Hugo Gee
LSU Doctoral Dissertations
Floodplains forests are productive and diverse ecosystems characterized by frequent riverine flooding. Levees and dams have eliminated or altered riverine flooding which can potentially affect floodplain tree recruitment and growth. Increased light availability from canopy disturbances may increase photosynthesis given sufficient soil moisture, but information on the combined effect of canopy disturbances and hydrologic modifications on tree recruitment and growth is lacking. I used dendrochronological techniques to reconstruct tree recruitment, growth (Quercus lyrata, Fraxinus pennsylvanica), and canopy disturbance patterns over a 90-year period at several floodplains in the Mississippi River Alluvial Valley, USA: an unleveed site below dams and two …
Effect Of Hydrology On The Structure And Function Of Mangrove Ecosystems In The Can Gio Mangrove Biosphere Reserve, Vietnam, Loi Tan Le
LSU Doctoral Dissertations
The influence of hydrology on the mangrove forests of Vietnam has received little scientific attention, even though hydrology is recognized as the primary forcing function in mangrove ecosystems worldwide. The purpose of this dissertation research was to determine the effects of hydrology on specific structural attributes and functional processes within the mangrove forests of Can Gio, a province in southeastern Vietnam. Khe Vinh (KV) and Mui O (MO), two locations within compartment 17 of the Can Gio Mangrove Biosphere Reserve, were chosen as study sites. This research addressed two questions: (1) What are the characteristics of the hydrological regime at …
Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss
Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss
LSU Doctoral Dissertations
Wetland groundwater hydrology was investigated at different spatial scales to assess the usefulness of the information to coastal managers. Specific objectives were to: (1) review studies related to coastal groundwater discharge, evaluating techniques and identifying controls; (2) understand regional trends in groundwater flow along the U.S. East and Gulf coasts; (3) evaluate the applicability of naturally occurring radioisotopes as indicators of groundwater in a shallow deltaic system; and (4) evaluate groundwater-surface water exchange within Barataria Basin, Louisiana. Results of the review confirmed discharge estimates vary over several orders of magnitude, due to differences in precipitation and tidal prisms. In addition, …