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Occurrence, Toxicity, And Diversity Of Pseudo-Nitzschia In Florida Coastal Waters, Sheila O'Dea

USF Tampa Graduate Theses and Dissertations

Domoic acid (DA), a potent neurotoxin that has the potential to cause amnesic shellfish poisoning (ASP), is produced by members of the marine diatom genus Pseudo-nitzschia. Outbreaks of ASP in humans and of DA poisoning in birds and marine mammals have been reported across the United States and Canada since the late 1980's. Pseudo-nitzschia species can be extremely abundant in Florida waters, with densities often exceeding 10⁶ cells/L, and sometimes exceeding 10⁷ cells/L. Based on preliminary data, it is evident that at least nine species of Pseudo-nitzschia are found in Florida coastal waters. At least six of …

Impacts Of Artificial Reefs On Surrounding Ecosystems, Sarine Manoukian

USF Tampa Graduate Theses and Dissertations

Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation.

Acoustic systems like high-frequency multibeam sonar are efficient tools …

Ecological Dynamics Of Livebottom Ledges And Artificial Reefs On The Inner Central West Florida Shelf, Jennifer Maria Dupont

USF Tampa Graduate Theses and Dissertations

The West Florida Shelf (WFS) is one of the largest and most diversely-used continental shelf/slope systems in the world. The presence of paleoshorelines and scarped hardbottom outcrops (up to 4 m in relief) along the inner shelf (10-30 m depth) provide important habitat for a variety of infaunal, epifaunal, and fish assemblages that contribute to the productivity of the region. This dissertation will present a comprehensive overview of the geological, physical, and chemical settings of the inner West Florida Shelf, with particular focus on biological and ecological community dynamics of epibenthic macroinvertebrates, algae, and fish assemblages. Baseline and comparative data …

Application Of Remote Sensing Methods To Assess The Spatial Extent Of The Seagrass Resource In St. Joseph Sound And Clearwater Harbor, Florida, U.S.A., Cynthia A. Meyer

USF Tampa Graduate Theses and Dissertations

In the event of a natural or anthropogenic disturbance, environmental resource managers require a reliable tool to quickly assess the spatial extent of potential damage to the seagrass resource. The temporal availability of the Landsat 5 Thematic Mapper (TM) imagery, 16-20 days, provides a suitable option to detect and assess damage to the seagrass resource. In this study, remote sensing Landsat 5 TM imagery is used to map the spatial extent of the seagrass resource. Various classification techniques are applied to delineate the seagrass beds in Clearwater Harbor and St. Joseph Sound, FL. This study aims to determine the most …

Evolution And Field Application Of A Plankton Imaging System, Andrew Walker Remsen

USF Tampa Graduate Theses and Dissertations

Understanding the processes controlling the distribution and abundance of zooplankton has been a primary concern of oceanographers and has driven the development of numerous technologies to more accurately quantify these parameters. This study investigates the potential of a new plankton imaging sensor, the shadowed image particle profiling and evaluation recorder (SIPPER), that I helped develop at the University of South Florida, to address that concern. In the first chapter, results from the SIPPER are compared against concurrently sampling plankton nets and the optical plankton counter (OPC), the most widely used optical zooplankton sampling sensor in the field. It was found …

A Three-Dimensional Biophysical Model Of Light, Nutrient, And Grazing Controls On Phytoplankton Competition Affecting Red Tide Maintenance On The West Florida Shelf, Scott P. Milroy

USF Tampa Graduate Theses and Dissertations

A coupled, three-dimensional, time-dependent numerical model of water circulation, spectral light, plankton dynamics, nutrient/CDOM loadings, and zooplankton grazing provided an assessment of the factors affecting the growth and maintenance of red tides on the west Florida shelf (WFS). The coupled biophysical model consisted of state variable quantities for temperature, salinity, horizontal/vertical velocity components, turbulent diffusion, spectral light, colored dissolved organic matter (CDOM), dissolved organic and inorganic carbon, particulate silica, four dissolved inorganic nutrient pools (nitrate, ammonium, phosphate, and silicate), and four phytoplankton groups (diatoms, microflagellates, non-toxic dinoflagellates, and the red tide organism Karenia brevis).

The model also included a complex …

Late Holocene Planktic Foraminiferal Assemblages From Orca Basin: Effects Of Dissolution On Faunal Assemblages, Denise D. Palmer

USF Tampa Graduate Theses and Dissertations

Studies of planktic foraminifers have been, and continue to be, very important to paleoceanographic reconstructions and are dependent on the integrity of the carbonate tests. This study investigates the methods and procedures that can be used to obtain an accurate planktic foraminifer assemblage. Samples from Orca Basin boxcore OB-BC4D were processed and examined to obtain census data on planktic foraminifers. Experimentation of the splitting technique demonstrates the method is acceptable for estimating a planktic foraminifer assemblage. The effects of a sonication step in the processing of the faunal assemblage were also examined and revealed that sonication is not recommended for …

Diversity And Production Of Phytoplankton In The Offshore Mississippi River Plume And Coastal Environments, Boris Wawrik

USF Tampa Graduate Theses and Dissertations

River discharge leads to extensive phytoplankton blooms often observed in ocean color satellite images to extend far into the open ocean as high chlorophyll plumes. We investigated diversity, distribution and ecology of phytoplankton populations in the Mississippi River plume, both spatially and in the water column using molecular tools. A method was developed for the quantification of diatom/pelagophyte rbcL (large subunit of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase) mRNA using quantitative PCR and applied to cultures and in the plume. The vertical structure of phytoplankton species in the Mississippi River plume was described by flow cytometry, pigments, rbcL mRNA and rbcL cDNA libraries. High …