Date of Award

Fall 12-14-2018

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Marine Science

College

College of Science

First Advisor

George Boneillo

Abstract/Description

The aim of this study was to investigate the differences in nutrient limitation within the beach and marsh environments at Waties Island, SC. Conducting the experiment on Waties Island allowed most physical factors to be held as constant, meaning the marsh and beach environments would serve as the only variables. Experiments were performed in the winter, spring, summer and fall of 2018 to determine temporal changes in limitation to phytoplankton and cyanobacteria growth. Nutrient additions included dissolved inorganic nitrogen (nitrate, nitrite, and ammonium), dissolved organic nitrogen (urea), and phosphate. To test for co-limitation, a nitrate & phosphate treatment was also used. Triplicate treatments were incubated for 48 hours in a Thermo Scientific Precision Model 818 Incubator. Changes in phytoplankton and cyanobacteria biomass were determined by monitoring chlorophyll, phycocyanin, and phycoerythrin concentrations fluorometrically. What was found was typical of coastal marine environments in the southeastern United States; that nitrogen is the main limiting nutrient and each species of nitrogen exhibited a significant difference in growth from the control. Between the marsh and beach environments, the marsh exhibited higher control growth rates, while the beach was the more nutrient limited environment. Seasonally, the marsh became less nutrient limited as the seasons progressed from winter to fall, while the beach maintained constantly limitation year-round. Within the marsh, cyanobacteria were found to be non-nutrient limited however phosphorus caused a significant depression in cyanobacteria growth. In the beach, the primary cyanobacteria nutrient was phosphorus while nitrogen served as the secondary limiting nutrient.

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