College of Arts and Sciences
Master of Science in Biology (MS)
NACO controlled Corporate Body
University of North Florida. Department of Biology
Dr. Dale Casamatta
Dr. Anthony Rossi
Dr. Kelly Smith
Dr. Daniel C. Moon
Dr. Barbara A. Hetrick
Cyanobacteria are important components of the aquatic system, valued for their oxygen production, nitrogen fixation, and as the base of many aquatic food webs. This study investigated several aspects of cyanobacteria such as the diversity and response to nutrient enrichments. A survey of Northeast Florida was conducted between the years of 2010 and 2012; a total of 145 taxa were identified in freshwater habitats, such as springs, lakes, rivers, and retention ponds. While surveying the St. Johns River in Jacksonville, Florida, a novel Stigonematalean taxon was isolated and cultured. Subsequent morphological and genetic analyses indicate that this taxon is related to Fischerella, Nostochopsis, and Westelliopsis, though with poor bootstrap support. Thus, a new genus and species (Reptodigitus chapmanii gen. et sp. nov.) is proposed. Cyanobacterial community shifts are increasingly being employed as an indicator of ecosystem health. The last part of this study is an experimental manipulation of nutrients and subsequent community analyses. Chlorophyll a, total number of cells, and Dmax were significantly different between control groups and nutrient enriched groups. Phosphate was not strongly correlated to species richness, chlorophyll a, evenness, total number of cells, species richness, or diversity in either the control or the nutrient enriched groups. Nitrogen displayed similar results, though it was slightly more strongly correlated to evenness and diversity in the nutrient enriched group than the control group. The results of the survey and nutrient enrichment experiment are important parts of the investigation into how cyanobacterial communities respond to changes in nutrient concentrations, which can then be used to devise a standard metric against which water management agencies can compare to determine the health of a given aquatic system.
Stocks, Holly Stephanie, "A Survey of the Taxonomy of the Cyanobacteria from Northeast Florida, Descriptions of Novel Taxa, and an Investigation into the Factors Which Influence the Epibenthic Cyanobacterial Community" (2013). UNF Graduate Theses and Dissertations. 480.