Life Sciences Commons^™

Management Of Biological And Chemical Constituents For The Advancement Of Intensive, Minimal-Exchange, Biofloc-Based Shrimp (Litopenaeus Vannamei) Aquaculture, Andrew James Ray

Dissertations

Intensive, minimal-exchange, biofloc-based shrimp aquaculture systems may provide a sustainable alternative to traditional shrimp culture. Through a series of experiments, this document explores the effects of several key management strategies on water quality, isotopic distribution, and shrimp production.

An experiment evaluated the effects of managing suspended solids (biofloc) concentration at two levels. It was found that using a higher flow rate to larger settling chambers resulted in significantly lower biofloc and nitrate concentrations, and significantly improved shrimp growth rate. A second experiment compared systems with clear water and systems with biofloc. The filters in the clear water systems prevented biofloc …

Fluorescence And Size Characterization Of Dissolved Organic Matter In Riverine And Sea Waters In The Northern Gulf Of Mexico, Zhengzhen Zhou

Dissertations

Riverine export of dissolved organic matter (DOM) is an important component in marine carbon budget but the composition and phase partitioning are poorly quantified. Monthly water samples were collected from the lower Mississippi and Pearl rivers between January 2009 to August 2011 for DOM characterization using the fluorescence excitation emission matrix (FluoEEM) technique, coupled with parallel factor analysis (PARAFAC), and flow field-flow fractionation technique. DOM in the Pearl River showed higher dissolved organic carbon (DOC) concentration, temporal fluctuation, and aromaticity, reflecting instantaneous inputs of DOM from local soil and plant litter. In contrast, DOM in the Mississippi River exhibited lower …

The Use Of Diatoms To Infer Environmental Change Of The Lower White River, Southeastern Arkansas, Ruchi Bhattacharya

Graduate Theses and Dissertations

This dissertation describes the limnology of the lower White River oxbow lakes in southeast Arkansas, inundated by the major 2008 spring flood. The flood water and sediment deposited in oxbow lakes were analyzed for water chemistry, sediment geochemistry and diatom assemblages and used as an analogue for past floods. The 2008 spring flood inundated and homogenized the entire floodplain; also represented by the predominantly planktonic diatom assemblage suggesting riverine input. Indicator species for eutrophication were also recorded consistent with the high nutrient content in the lakes. However, the variance in the surface diatom assemblage was best explained by the lake …

A 1,461-Year Growing Season Precipitation Reconstruction For The Carolina Coastal Plain, Kathryn Perkins Wolff

Graduate Theses and Dissertations

A recollection and dating of ancient cypress trees and subfossil logs was performed at Black River, North Carolina, and the separate Black River, South Carolina. The new updated and expanded chronologies date from AD 365 to 2010 and 549 to 2010, respectively. Baldcypress ring-width chronologies are dominated by high inter-annual to decadal variability and do not tend to capture century scale fluctuations in tree-ring growth that could be associated with centennial scale change in climate. The tree-ring chronologies were standardized with a technique designed to preserve low frequency variance known as regional curve standardization. The two chronologies were averaged into …