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Full-Text Articles in Life Sciences

Effects Of Freshwater Input On Nutrient Loading, Toxic Cyanobacteria Bloom Development And Cyanotoxin Production In Lake Pontchartrain Estuary, Louisiana, Callie L. Snow Nov 2021

Effects Of Freshwater Input On Nutrient Loading, Toxic Cyanobacteria Bloom Development And Cyanotoxin Production In Lake Pontchartrain Estuary, Louisiana, Callie L. Snow

LSU Master's Theses

Estuaries in the northern Gulf of Mexico (GoM) are undergoing profound alterations due to changes in climate and implementation of coastal restoration activities and these may lead to the increasing frequency of harmful algal blooms (HABs). The introduction of large volumes of nutrient-rich, fresh Mississippi River water into nutrient-poor Lake Pontchartrain Estuary is known to substantially change the chemistry and ecology of the estuary, and warm temperatures paired with the persistent nutrient loading into the estuary supports the proliferation of potentially toxic cyanobacteria blooms (CyanoHABs). Throughout 2019, a long-term opening of the Bonnet Carré Spillway (BCS), initially from February to …


Blue Carbon In South Florida's Mangroves: The Role Of Large Roots And Necromass, Zoë I. Shribman Sep 2021

Blue Carbon In South Florida's Mangroves: The Role Of Large Roots And Necromass, Zoë I. Shribman

LSU Master's Theses

Blue carbon sequestration and storage in mangroves largely result from belowground biomass allocation in response to flooded anaerobic soil conditions and nutrient availability. Biomass allocation to belowground roots is a major driver of mangrove soil formation and organic matter accumulation leading to blue carbon storage potential. Belowground biomass sampling in mangroves is labor intensive, limiting data availability on biomass stocks, particularly for large roots (>20 mm diameter) and necromass (dead roots). The mangrove nutrient model (NUMAN) uses mostly literature values to parameterize a soil cohort approach to simulate depth distribution of root mass and organic carbon concentration. We evaluated …


Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija Jul 2021

Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija

LSU Master's Theses

Spring-fed arid wetlands support high biological productivity and are hotspots for endemism and distribution of rare plants, making them areas of high conservation value. These systems are driven by complex interactions among groundwater discharge and the geomorphic and climatic features of the setting, which provide gradients of edaphic conditions, particularly soil moisture and salinity that influence the presence and abundance of rare plant communities. However, spring-fed arid wetlands are at particular risk of increases in salinity and drier hydrological regimes due to anthropogenic activities. Such alterations to abiotic conditions may jeopardize the distribution and abundance of rare plants by exceeding …


Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam Jul 2021

Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam

LSU Master's Theses

Eastern oysters (Crassostrea virginica) provide valuable ecosystem services and support a productive commercial industry in the northern Gulf of Mexico. Declining abundance from water quality changes and other factors drives development of management and restoration strategies focused on a comprehensive, metapopulation approach. Identifying oyster resource zones based on water quality combined with selective breeding of oysters adapted to specific conditions provides strategies to support aquaculture development and ensure resilient oyster populations and high production. Using 2015-2019 satellite-derived continuous salinity and temperature data for coastal Louisiana, this work created maps defining oyster resource zones supportive of (1) broodstock sanctuary …


Plant Community Response To The Combined Effects Of Elevation, And Simulated Nutrient And Sediment Loading In Sagittaria Lancifolia-Dominated Wetlands, Donnie Day Mar 2021

Plant Community Response To The Combined Effects Of Elevation, And Simulated Nutrient And Sediment Loading In Sagittaria Lancifolia-Dominated Wetlands, Donnie Day

LSU Master's Theses

Coastal wetlands are experiencing threats to their long-term sustainability brought about by the combined effects of relative sea-level rise and human modifications to hydrology, sediment delivery and nutrient loading. Restoration and management strategies can include adding sediment to the surface of deteriorating marshes to facilitate positive feedbacks among elevation, plant productivity, sediment trapping, and accretion; however, if delivered using nitrate-enriched river waters, belowground biomass and soil organic matter pools may be negatively affected, resulting in the acceleration of wetland loss. Overall, there is limited information on the combined effects of nutrient loading, sedimentation, and flooding dynamics in regulating feedbacks among …