No description available.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 127-140). Also available via the Internet.

Thesis (Ph.D.)--University of Texas at Arlington, 2009.

Thesis (M.S.)--Marshall University, 2003. / Title from document title page. Includes abstract. Document formatted into pages; contains ix, 111 including illustrations. Includes bibliographical references (p. 49-71).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-139).

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 27, 2007) Includes bibliographical references.

Dissolved organic matter (DOM) is the largest reservoir of organic matter in the ocean containing the same amounts of carbon as atmospheric carbon dioxide. DOM consists of a mixture of compounds ultimately originating from terrestrial and aquatic plant, and microbial materials. The complex chemical composition of DOM results in varying availability to microbes, containing a pool that is readily utilized by heterotrophic bacteria and a refractory part that resists biological degradation. In this study the seasonal variation in bioavailability of DOM was quantified in two contrasting marine systems: Loch Creran (Scotland) and the Ría de Vigo (Spain). The bioavailable DOM (BDOM) varied temporally at both stations and controlled the seasonal variations in DOM. Dissolved organic phosphorus (DOP) was found to be more bioavailable than dissolved organic nitrogen (DON) and DON was more bioavailable relative to dissolved organic carbon (DOC). The variation in BDOM was, in both areas, associated with changes in chlorophyll a. The DOM rate constants were observed to vary seasonally and they demonstrated that higher BDOM concentrations would lead to faster mineralization rates. Calculations from both areas suggested that they exported BDOM, which could contribute to bacterial production in the adjacent waters. It is shown that BDOM produced in the Ría de Vigo, with a half life time of 1.9 - 3.3 days, is significantly more labile than that produced in Loch Creran, with a half life time of 6 - 13 days. A fraction of DOM is coloured containing a part that absorbs (CDOM), and a part that absorbs and reemits the energy again (Fluorescence, FDOM). The relation between the optical properties of DOM and the bioavailability of DOC was tested in the Ría de Vigo. This study demonstrated that it was possible to derive both the bioavailable DOC and its rate constants from the DOM protein-like fluorescence, whereas refractory DOC could be estimated from in situ CDOM and humic-like substances in the Ría de Vigo. Heterotrophic microbes have often been viewed as the main consumers of DOM, but it is now evident that they can also produce DOM. The heterotrophic microbial production of DOM was studied using microbial communities from Loch Creran. The experiments demonstrated that the microbes produced refractory and labile DOM with a coloured signal.

Typescript, etc.

Estuaries have been identified as hotspots of microplastic pollution because they are transitional zones where coastal freshwater and oceans converge. Microplastics (MP) are transported through estuaries by a dynamic series of forces such as surface flow and tides, which influence MP abundances and trends. The eastern oyster, Crassostrea virginica, is an estuarine bivalve known to ingest MP, resulting in negative impacts on organism physiology. I investigated MP pollution as a threat to C. virginica in a dynamic Florida estuary, the Indian River Lagoon (IRL), and determined there are both regional and small-scale spatial and temporal fluctuations in MP abundance. Tributaries were identified sources of MP, while inlets flush them out of the system. The south IRL is a hotspot for MP, where the St Lucie Estuary is the primary tributary. Throughout the IRL, fibers dominated MP and polyethylene terephthalate (PET) was the most abundant polymer type ( > 50%). Overall, C. virginica had a mean of 2.2 MP/individual and lagoon water had 1.5 MP/L. An in-situ biodeposition experiment revealed C. virginica of all sizes were able to egest environmental MP at a rate of 1 MP per 1 hour through feces, and 1 MP per 2 hours through pseudofeces. Oysters had a mean MP egestion efficiency of 62.1%, and 32.1% of oysters were able to egest all MP from their tissues within 2 hours. Smaller C. virginica were more efficient at egesting MP, and egestion efficiency decreased by 0.8% for every 1-g increase in tissue weight. Overall, I provide an argument that MP are ubiquitous in this hydrologically dynamic estuary in both the water and in a keystone, filter-feeding invertebrate. I estimate there are currently ~1.4 trillion microplastics in the Indian River Lagoon.

Mangrove living shorelines are an effective alternative to hard-armoring, which combat erosion while also increasing habitat. To improve the success of future mangrove deployments, an experimental Rhizophora mangle living shoreline was deployed within Mosquito Lagoon, FL. A factorial design was used to test the impact of mangrove age, breakwater presence, and mangrove placement on mangrove survival and growth. Environmental factors were monitored to isolate the reason for mangrove mortalities. Mangrove age was represented by 3 developmental stages: "seedlings" at 11-months-old, "transitionals" at 23-months-old, and "adults" between 35 and 47-months-old. Mixed mangrove age groups were included to identify if seedling survival could be facilitated by the presence of transitionals and adults; control groups were used to test the impact of restoration materials on recruitment of wrack and mangrove propagules. The majority of mangrove mortalities (62%) occurred 2 months after the onset of high-water season and these dead mangroves showed signs of flooding stress. Breakwaters alleviated stress through the reduction of water velocity and wave height, and increased the odds of survival by 197% and 437% when mangroves were planted in the landward and seaward rows, respectively. Due to their larger stems and greater number of prop roots, older mangroves were better able to survive; compared to seedlings, transitionals increased survival odds by 186% and adults by 1087%. For treatments composed of adults and a breakwater, 88% of the mangroves survived and 64% of these survivors produced flowers or flower buds by 12 months after the restoration. Planting seedlings haphazardly among older mangroves did not attenuate enough wave energy to significantly increase seedling survival, and the complexity of restoration materials did not significantly impact propagule or wrack abundance.