The Indian River Lagoon, Florida, is a unique closed “bar built” estuary system that has little interchange with the Atlantic Ocean and which is home to many resident species. Three fish species were investigated to see if their isotopic and fatty acid signatures differed based on geographic location. The goal was to assess the degree of resolution of spatial variation that is possible when using stable isotope and fatty acid signature analysis to interpret feeding habits and potential linkages between feeding habits and health status. Spotted seatrout (n=40), pinfish (n=60) and white mullet (n=60) were collected over a 4 week period at sites 30 km apart in two distinct biogeographic regions of the IRL. Fish were analyzed for stable isotope (δ13C and δ15N) and fatty acid composition. All three species were significantly different from each other in both isotopic and fatty acid signatures. In the North Indian River segment, spotted seatrout, white mullet and pinfish had mean values (± SE) for δ13C of -18.00 ± 0.08, -14.59 ± 0.07 and -16.88 ± 0.04 respectively and for δ15N, mean values were 14.43 ± 0.05, 8.30 ± 0.04 and 10.43 ± 0.03 respectively. For the North-Central Indian River segment, spotted seatrout, white mullet and pinfish had mean values for δ13C of -18.98 ± 0.02, -16.25 ±0.06 and -16.94 ± 0.04 respectively and for δ15N, mean values were 14.21 ± 0.02, 8.07 ± 0.03 and 10.64 ±0.03 respectively. When species and location interactions were examined using ANCOVA, a post-hoc Tukey’s HSD test showed that δ13C was significantly affected by sampling segment only for spotted seatrout and that there was no significant effect of location on δ15N values. Spotted seatrout was the only species that differed between segments for δ13C. Classification and Regression Tree (CART) analysis was then performed on the “extended dietary fatty acids” for each individual species and collection location. In this analysis, all three species were correctly identified to segment (white mullet - MR 2/53 p~ 0.03; spotted seatrout (MR 0/40), and pinfish (MR 0/56) indicating that individual species were exhibiting significant differences in their fatty acid signature over distances of 30 km. The ability to discern fine-scale differences in potential prey allows for the possibility of better resolution of dolphin feeding habits and hence a better understanding of both habitat utilization and health impacts. Due to limited exchange of clean salt water, contaminants can theoretically become a problem and there are indications that the health of the resident population of bottlenose dolphins (Tursiops truncatus) has been declining over recent years.

Vibrio choleraeis the etiological agent of the severe diarrheal disease-cholera and natural inhabitant of estuarine and coastal waters. The proximity of the Florida Indian River Lagoon (IRL) to areas affected by recent cholera outbreaks makes this estuary ideal to investigate the environmental dynamics and their potential role in V. cholerae's pathogen emergence. We identified two locations in the IRL, Feller's House UCF Field Station and Shepard Park, as our collection sites. We collected samples from three different fractions - water, plankton, and sediment - and recorded data for several water parameters such as pH, temperature, and, turbidity. In the laboratory, we enriched samples in alkaline peptone water and isolated V. choleraeusing widely used selective media Thiosulfate-Citrate Bile Salts-sucrose agar (TCBS) and CHROMagar Vibrio. From our study, we isolated 100 potential V. cholerae isolates, which were confirmed using biochemical tests such as oxidase and Kligler's Iron Agar. V. cholerae has allelic variations in the core genes such as ompU, which provide pre-adaptation to virulence. We investigated the allelic variations within ompU to characterize V. cholerae isolates. We elucidated the sequenced allele of ompU and built a neighboring-joining phylogeny tree to view the differentiation among vibrios. Our findings provide insight into the endemic population of V. cholerae in the Eastern Coast of Florida. Further studies include a screen for additional virulence genes and investigate the role of environmental dynamics on the distribution of V. cholerae and emergence as a human pathogen.

Crassostrea virginica, the eastern oyster, is a native keystone species that inhabits many coastal and estuarine ecosystems along the Atlantic seaboard. Introduction of the eastern oyster into estuarine areas with limited current populations is gaining popularity as a pro-active approach to improve estuarine water quality. In November 2014 and April 2015, a total of five pilot oyster reef treatments were deployed in Brevard County: bagged adult oysters (grown by community members under their docks through oyster gardening) collected in fall 2014 and spring 2015, bagged clean shell, oyster restoration mats, and empty plots (control). Locations of deployment included a Merritt Island impoundment (Marsh Harbor), Nicol Park (Port St. John), and Scout Island (Melbourne Beach). Prior to deployment, we collected morphometric data (shell length, weight) on all gardened oysters. Abiotic factors including salinity, air and water temperature, and wind speed were collected monthly. During quarterly sampling at each site, morphometric data were collected for all live oysters, surviving and newly recruited. Results show survival of gardened oysters and natural recruitment differed by and depended greatly on the within-site location of each reef. In areas with no recruitment and limited gardened oyster survival, regular deployment of gardened oysters is needed for long term success. In areas with natural recruitment, bagged, clean shell or oyster restoration mats are most successful. Future restoration sites should be tested prior to any large-scale oyster deployments.

Mangrove stands and oyster reefs are two common coastal habitats in the Indian River Lagoon. Each habitat provides diverse ecosystem services, including carbon sequestration and carbon storage. A decrease in freeze events and an increase in sea levels are leading to mangrove habitat expansion, including encroachment onto live oyster reefs in the IRL’s northernmost portion, Mosquito Lagoon. This study investigates how the encroachment of black mangroves (Avicennia germinans) and red mangroves (Rhizophora mangle) on eastern oyster reefs (Crassostrea virginica) impacts the abundance and stability of soil carbon relative to each habitat alone. Soil and sediment samples (0-10cm) were collected from three locations in Mosquito Lagoon, each containing a mangrove-only, oyster-only, and mangrove-encroached oyster reef habitat. Total and active carbon were quantified, and stable carbon was determined through physical and density fractionation that isolates persistent mineral-associated organic matter (MAOM). Results showed total, active, and MAOM-carbon averaged 2-3 times greater in mangroves than oyster reefs, while mangrove-encroached oyster reefs were intermediate in concentration. However, mangrove-oyster soils have the highest proportion of the total carbon pool protected as MAOM (54.9%), compared to each habitat alone (mangrove-only, 35.3%, oyster-only, 30.3%). This research is the first to provide data on blue carbon storage in areas where mangroves encroach on oyster reefs, including differentiating total carbon based on its stability in the soil.