Paper Type

Master's Thesis


College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)



NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Dr. Nicole Dix

Second Advisor

Dr. Samantha Chapman

Third Advisor

Dr. Dale Casamatta

Department Chair

Dr. Cliff Ross

College Dean

Natasha Christie


The ecotone in Northeast Florida is experiencing rapid change as mangroves begin to encroach northward into saltmarsh dominated coastal wetlands. This is especially prevalent within the boundaries of the Guana Tolomato Matanzas National Estuarine Research Reserve where studies are attempting to understand the consequences of more mangroves. Although we are beginning to understand some of the implications of this shift in dominant vegetation, the true effects and the accompanying sustained climatic warming effects on the resilience of wetland habitats and their associated communities remains unknown. Primary producers such as benthic microalgae (BMA) are important food sources in both mangrove and saltmarsh communities and can provide insights into how changes can affect community dynamics. Algal community biomass and composition was measured within three different marsh vegetation types (Batis maritima, Spartina alterniflora, and Avicennia germinans) and compared to assess if vegetation is a potential driver of algal community dynamics. Warming chambers deployed on both marsh dominated and mangrove dominated plots were also used to investigate how warming could potentially drive algal community change. Abiotic conditions and vegetation structure were assessed as potential structuring forces on algal communities. Algal biomass and functional group diversity differed among vegetation types and varied by season. Abiotic factors (temperature, light) and vegetation structural properties (% cover, stem height, stem density) were correlated with patterns of algal biomass. Algae biomass and functional group diversity also responded to increased air temperature treatments in the spring with community shifts towards cyanobacterial dominance in warming treatments. These findings suggest that changes in BMA communities should be investigated further as potential bottom up drivers of community shifts resulting from the marsh to mangrove transition.