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Full-Text Articles in Physical Sciences and Mathematics

Physical And Biological Factors Controlling The Fate Of Nitrate In A Louisiana Coastal Deltaic Floodplain, Alexandra Christensen Apr 2020

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 …


Habitat Preferences Of Adult Spotted Seatrout, Cynoscion Nebulosus, In Lake Pontchartrain, Louisiana, Noelle Marie Bramer Jan 2015

Habitat Preferences Of Adult Spotted Seatrout, Cynoscion Nebulosus, In Lake Pontchartrain, Louisiana, Noelle Marie Bramer

LSU Master's Theses

Spotted seatrout (Cynoscion nebulosus) are a highly sought after sportfish, making up over 90% of the recreational fishery in Louisiana. As a significant portion of every life history stage is spent within its natal estuary, it is an ideal bio-indicator of estuarine health. As one of the largest estuaries in Louisiana, Lake Pontchartrain represents one such supporting ecosystem. From November 2012 to April 2014 acoustic tagging of individual fish, a lake-wide receiver array, and ArcGIS mapping software were utilized to determine the spatial distribution of spotted seatrout within the lake. Receivers were placed in representative locations including man-made and natural …


Dissolved Oxygen Dynamics And Modeling - A Case Study In A Subtropical Shallow Lake, Zhen Xu Jan 2014

Dissolved Oxygen Dynamics And Modeling - A Case Study In A Subtropical Shallow Lake, Zhen Xu

LSU Master's Theses

As one of the most valued and treasured natural resources, today many lakes in the world face degradation of their water quality due to nutrient enrichment, toxic contamination, and hydrological modification from their drainage areas. Among various water quality impairments, dissolved oxygen (DO) depletion is often a leading stressor in lake systems. Despite numerous studies on DO in deep water lakes in temperate regions, the knowledge of DO dynamics in eutrophic shallow lakes in subtropical regions is still limited. This thesis research conducted intensive DO monitoring in an eutrophic shallow lake in south Louisiana to characterize diel cycles of DO …


Water Quality Dynamics Of Low-Gradient, Headwater Streams In A Timber-Industry Dominated Watershed In Louisiana, Abram Atys Dasilva Jan 2012

Water Quality Dynamics Of Low-Gradient, Headwater Streams In A Timber-Industry Dominated Watershed In Louisiana, Abram Atys Dasilva

LSU Master's Theses

Timber harvesting can degrade the quality of adjacent water bodies, an important concern for Louisiana, nearly 50% of which is forested, and in which the forest industry is the second-largest manufacturing employer. To protect valuable freshwater resources in Louisiana, a manual of best management practices (BMPs) was published in 2000 describing techniques for limiting forestry-caused water quality degradation. While these BMPs are widely implemented, their effectiveness in protecting water quality is largely unknown. To determine the effectiveness of these BMPs, this thesis research conducted three studies to address timber harvest BMP effectiveness on protection of stream dissolved oxygen, metabolism, and …


Land Use And Water Quality Characterization Of Boeuf Basin, La, Joseph Wesley Leblanc Jan 2008

Land Use And Water Quality Characterization Of Boeuf Basin, La, Joseph Wesley Leblanc

LSU Master's Theses

The three primary goals of this project were to establish the ambient background of water quality in the Lake Boeuf basin in southeast Louisiana; establish land use patterns in the basin and the relation to water quality; and develop a preliminary plan to improve water quality through the use of best management practices and wetland assimilation. Urban and agricultural acreage borders the basin and runoff from these lands forces loadings of nutrients into the adjacent canals where they become channelized and ultimately exit the Boeuf Basin into Lac des Allemandes. From September 2007 until February 2008, water sampling occurred monthly …


A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii Jan 2008

A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii

LSU Doctoral Dissertations

Human endeavors, particularly the agricultural and industrial activities of the last half century, now produce more biologically available nitrogen (N) than all other natural sources combined. The increased N availability can have consequences for the health of aquatic biota on the local, regional, and global scales. One manifestation of this problem is the formation of coastal hypoxic zones where terrestrial N loading creates eutrophic conditions in coastal waters. This dissertation examines a century of changes in land use and water quality to quantify the relationships between agricultural land use practices and riverine N yields in the Mississippi River Basin and …


Evaluation Of Compliance With The Long Term 1 Enhanced Surface Water Treatment Rule, Racquel Rena Douglas Jan 2007

Evaluation Of Compliance With The Long Term 1 Enhanced Surface Water Treatment Rule, Racquel Rena Douglas

LSU Master's Theses

Cryptosporidium is a common protozoan parasite that causes cryptosporidiosis, a severe gastrointestinal disease. Currently, there is no antibiotic available to treat the disease. Cryptosporidium has been responsible for several waterborne disease outbreaks in the United States. The largest cryptosporidiosis outbreak in United States history occurred in Milwaukee, Wisconsin in spring 1993. The vulnerability of the United State drinking water supply to waterborne disease outbreak is still prevalent nearly 15 years after the Milwaukee outbreak. In order to effectively control Cryptosporidium, the EPA has strengthened the regulations on turbidity control for filtration performance by implementing the Long Term 1 Enhanced Surface …


Early Flotant Establishment And Growth Dynamics In A Nutrient Amended Wetland In The Lower Mississippi River Delta, Caleb W. Izdepski Jan 2007

Early Flotant Establishment And Growth Dynamics In A Nutrient Amended Wetland In The Lower Mississippi River Delta, Caleb W. Izdepski

LSU Master's Theses

Nutrient dynamics and seasonal marsh growth were examined in a newly formed Panicum virgatum floating marsh at Thibodaux LA. The floating marsh formed in a cleared area of forested wetland receiving secondarily treated effluent. Net Areal Primary Productivity (NAPP), total belowground biomass, NO3, and δ15N ratios varied significantly (P <0.05) along a 75m marsh transect while mean δ13C varied between plant species. The upland end of the transect had the highest NAPP (3876 g m-2y-1), total belowground biomass (4079.0 ± 298.5 g m-2), and mean NO3 (5.4 ± 2.9 mg l-1). The mean floating-marsh …


Relationships Between Macroinvertebrate Communities And Environmental Characteristics Of Headwater Streams In Central Louisiana, Adrienne Viosca Jan 2007

Relationships Between Macroinvertebrate Communities And Environmental Characteristics Of Headwater Streams In Central Louisiana, Adrienne Viosca

LSU Master's Theses

Headwater streams are an integral part of any watershed system because they strongly influence the physical, chemical, and biological components of downstream reaches. Little information exists about macroinvertebrate community structure, spatiotemporal variation, or their relationships with environmental factors in low-gradient headwater streams of the subtropical coastal plain region in the Southern US. These headwater streams are typically slow moving, capable of accumulating large amounts of organic material, and often become intermittent during the dry season. Research is needed to understand the effects of these unique characteristics on stream health and ecology. This study aimed to determine aquatic macroinvertebrate community structure, …


Factors Influencing The Participation In Environmental Stewardship Programs: A Case Study Of The Agricultural And Forestry Sectors In Louisiana, Carrie Castille Mendoza Jan 2006

Factors Influencing The Participation In Environmental Stewardship Programs: A Case Study Of The Agricultural And Forestry Sectors In Louisiana, Carrie Castille Mendoza

LSU Doctoral Dissertations

Considerable research has been conducted to evaluate the adoption of agricultural best management practices and their overall impact on improving environmental quality. However, limited studies have been conducted to evaluate the behavioral factors that influence the adoption of these practices in the context of educational programs The goal of this study is to determine the factors that influence farmer conservation behavior that might lead to an increased probability of improving agriculture and forestry watersheds. A conceptual model was developed to identify the: 1) identify landowner participation in watershed conservation projects, and 2) determine the factors influencing agriculture and forestry landowners …


The Effect On Water Quality Of Riverine Input Into Coastal Wetlands, Robert Raymond Lane Jan 2003

The Effect On Water Quality Of Riverine Input Into Coastal Wetlands, Robert Raymond Lane

LSU Doctoral Dissertations

This dissertation focuses on impact on water quality of two freshwater diversions, the Bonnet Carre Spillway and the Caernarvon freshwater diversion, as well as the Atchafalaya River Estuarine Complex. As water passed through the Bonnet Carre Spillway, there were reductions in total suspended sediment concentrations of 82-83%, in nitrite+nitrate of 28-42%, in total nitrogen (TN) of 26-30%, and in total phosphorus (TP) of 50-59%. The Si:N ratio generally increased and the N:P ratio decreased from the river to the plume edge in Lake Pontchartrain. At the Caernarvon diversion, there were reductions in concentrations of dissolved inorganic Si, N, and P …