Year

2013

Season

Spring

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Dr. Dale Casamatta

Second Advisor

Dr. Matthew Kimball

Third Advisor

Dr. Anthony Rossi

Department Chair

Dr. Daniel C. Moon

College Dean

Dr. Barbara A. Hetrick

Abstract

Epiphytes are organisms attached to plants and are responsible for the majority of primary productivity in many aquatic systems. While epiphytes serve as a valuable food resource to herbivores, they may prove deleterious to the host plant by competing for light and nutrients, as well as increasing sheer stress. This study evaluated the impacts of nutrient additions, nitrogen and phosphorus, on the epiphytic algal community on Spartina alterniflora over the course of two growing seasons. Three nutrient treatments (N, P, and N+P) and one control treatment were placed in a salt marsh in the Tolomato River during the growing seasons of 2011 and 2012. To assess community development, we examined biomass, ash-free dry mass (AFDM), chlorophyll-a levels, cell counts, and community diversity by algal division. The nutrient additions did not significantly alter any of the measured parameters in either sampling year. However, the sampling month did have a significant (pa, and community composition. A total of 155 infrageneric taxa were identified. Biomass tended to be dominated by diatoms and red algae, while cyanobacteria were most abundant. In both years, biomass was highest in the spring with a second smaller pulse in the fall. Conversely, chlorophyll-a levels varied between the years and did not show the same monthly patterns as AFDM. A laboratory study subjecting S. alterniflora to the same nutrient additions also found no significant effects of increased nutrients, but did observe temporal changes in biomass and chlorophyll-a levels. Overall, epiphytic growth was not influenced by nutrient additions in this study suggesting that this and other similar salt marsh systems may be resilient to anthropogenic eutrophication. Instead, other factors, such as light and herbivory, likely played a key role in determining epiphytic algal growth and community composition.

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