Abstract
Gambierdiscus is an epibenthic dinoflagellate genus containing some species that produce a toxin (ciguatoxin), which causes Ciguatera Fish Poisoning (CFP). These dinoflagellates live on macrophytes that are consumed by herbivorous fish and invertebrates, thereby introducing ciguatoxin into the reef food web through bioaccumulation and biomagnification processes. Such grazers are later predated on by larger fish, which when consumed by people, can lead to CFP. Other dinoflagellates coexist with Gambierdiscus spp., including potentially toxigenic Prorocentrum and Ostreopsis spp. The research presented here focuses on the community ecology of Gambierdiscus spp. and these other dinoflagellates, and the abiotic factors that affect their distribution, abundance, and compositions. New findings in this project have provided information about community dynamics and the influence of abiotic factors. The data suggest that physical and chemical parameters influence dinoflagellate densities and the differences in site community composition. These epibenthic dinoflagellates thrive in high temperatures but may compete in other environmental conditions. The three dinoflagellates were more abundant in the Florida Bay than Atlantic Ocean sites. The three dinoflagellates coexist, but there were no differences in abundances seasonally and between sites, suggesting subtle niche partitioning may be taking place.
