Life Sciences Commons^™

Relationship Between Coastal Vegetation Biomass With Elevation And Salinity Gradients, Ying Chen

Electronic Theses and Dissertations

Surges and waves generated by hurricanes and other severe storms can cause devastating damage to property and loss of life in coastal areas. Vegetation in wetlands and coastal fringes can reduce storm surges and waves while complementing traditional coastal defense approaches such as permanent levees, seawalls and gates. The effectiveness of marsh vegetation in attenuating storm surge energy and reducing soil erosion depends on the level of primary production at the time of the storm surge and the ability of marsh vegetation to recover rapidly from damage caused by the storm surge. Marsh production depends on a variety of abiotic …

Response Of Riparian Plant Communities To Hydrological Alteration: Are Seed Banks A Means Of Restoration?, Siobhan Boyer Gorham

Electronic Theses and Dissertations

The effects of anthropogenic modifications of stream systems on in situ plant community composition and seed bank composition were examined at five riparian sites in the Yazoo River watershed in northern Mississippi. This analysis was performed to determine if the soil seed bank can provide a means for the restoration of riparian floodplain plant communities. The study sites represented five different kinds of hydrological alteration: a highly incised riparian terrace isolated from the stream channel, a deforested original stream with reduced flow due to channelization and standing water due to levees, a forested original stream with reduced flow due to …

The Effects Of Seasonal Changes And Turbidity On Swimming Performance In White Crappie Pomoxis Annularis And Black Crappie Pomoxis Nigromaculatus., Caleb Joseph Gaston

Electronic Theses and Dissertations

Factors that affect swimming performance in fish can also affect fitness. I tested the effects of time of day, season and turbidity on swimming performance in black crappie Pomoxis nigromaculatus and white crappie Pomoxis annularis. These closely related fish co-occur and their relative abundance is thought to be governed by the levels of turbidity in the form of suspended sediments. Black crappie predominate in clear bodies of water and exhibited significantly greater critical swimming speeds in clear water than did white crappie during spring days and winter nights. A significant reduction in critical swimming speed was observed in black crappie …

Effect Of Uv-A Irradiance On Lipid Accumulation In Nannochloropsis Oculata, Rathy Srinivas

Electronic Theses and Dissertations

The marine microalgae Nannochloropsis spp. are of both ecological and economic importance as they contribute to the base of the food chain of marine systems, and can accumulate a considerable amount of lipids. Their lipids can be grouped into two categories, storage lipids, which are mainly triglycerides (TGs), and structural lipids, which are composed of polyunsaturated fatty acids (PUFAs). PUFAs are essential nutrients for both aquatic animals and humans, while TGs can be transesterified to produce biodiesel. Lipid formation in microalgae depends on several environmental factors and Nannochloropsis spp. have been shown to accumulate excess storage lipids under stressful conditions. …

Population Biology Of A Coastal Dune-Dwelling Spider (Arctosa Sanctaerosae) Along The Hurricane Disturbed Northern Gulf Of Mexico Coast, Robert A. Hataway

Electronic Theses and Dissertations

With the continued increase in the number of tourists visiting the Northern Gulf coast in the last century and the resulting development of this coastline the habitat of Arctosa sanctaerosae has become fragmented; and the sprawl of large cities along the coast has further degraded available habitat. In addition to anthropogenic disturbance to this coastal region, hurricanes are an additional and natural perturbation to the ecosystem. This habitat has seen a number of major tropical storms over the last decade and I have sought to explore the impact of habitat destruction and storm-induced disturbance on a species of spider endemic …

Conservation Genetics And Distribution Of The Yazoo Darter (Etheostoma Raneyi), Kenneth Alan Sterling

Electronic Theses and Dissertations

The Yazoo Darter is a range-restricted endemic fish in north-central Mississippi. Because the limited and fragmented range of this species puts it at risk of extinction, the Yazoo Darter has been classified as vulnerable or sensitive by several agencies and conservation organizations. However, the actual conservation status of this species is uncertain. Information necessary for conservation management is relatively sparse and is scattered among published and unpublished sources, particularly collection records. I have consolidated all known collection records for this species into a standardized database which has not only yielded valuable information presented here, but will provide a resource for …

Influence Of Vegetation On Sediment Bacterial Community Structure, Microbial Enzyme Activities And Phosphorus Retention In Constructed Freshwater Wetlands, Rani Menon

Electronic Theses and Dissertations

Agricultural activities are major sources of non-point pollutants causing eutrophication. Constructed wetlands are used as a best management practice for sequestration of nutrients from agricultural runoff. This dissertation focuses on the influence of vegetation on bacterial community structure, microbial enzyme activities, and phosphorus retention capacity of constructed wetland systems. A greenhouse experiment was conducted using unvegetated or vegetated mesocosms with Juncus effusus, Carex lurida or Dichanthelium acuminatum var. acuminatum in monoculture or mixed culture.

To study the influence of vegetation on the bacterial community structure and microbial enzyme activities, sediment samples were taken from monoculture mesocosms in the greenhouse. β-1,4-glucosidase, …