Distribution of Potentially Toxic Epiphytic Dinoflagellates in Saint Martin Island (Caribbean Sea, Lesser Antilles)

Abstract

For the first time, distribution of epiphytic dinoflagellates was studied in Saint Martin Island (Lesser Antilles) during the cyclonic season (between September 1 st and 3 rd 2015). The present study provides a semi-quantitative analysis because the fresh weight of each macrophyte was estimated around 10 g. The identified genera were: Ostreopsis, Prorocentrum, Coolia, Amphidinium, and Gambierdiscus in order of decreasing abundance. Highest average abundance values of the genera Ostreopsis and Amphidinium were hosted by macrophytes of the Phaeophyceae group with ca. 15,000 and 60 cells g -1 respectively. Epiphytic Coolia cells were mainly observed on seagrasses with the highest average abundance value of ca. 1000 cells g -1 whereas the genera Gambierdiscus and Prorocentrum were principally associated with Florideophyceae with the highest average abundances of ca. 70 and 1500 cells g FW -1 respectively. This preliminary study indicates the most relevant locations to survey the biodiversity of potentially toxic epiphytic dinoflagellates in Saint Martin Island.

First insights on the diversity of the genus Ostreopsis (Dinophyceae, Gonyaulacales) in Guadeloupe Island, with emphasis on the phylogenetic position of O. heptagona

“…This work is however essential to generate a reference dataset of sequences, which constitutes a prerequisite for further development of molecular techniques based on environmental DNA such as probes for fluorescent in situ hydridization assay (Pitz et al, 2021), RT-PCR assays and metabarcoding analyses. While light microscopic observations can accurately estimate the abundance of the genus Ostreopsis (Boisnoir et al, 2018(Boisnoir et al, , 2019(Boisnoir et al, , 2020 studying species distribution, dynamics and phenology will be facilitated by implementation of such tools at the scale of the Caribbean.…”