Fluorescent epibiotic microbial community on the carapace of a Bahamian ostracod

Abstract

Ostracods collected from shallow coral reefs in the Bahamas were found to exhibit blue light-stimulated orange fluorescence at night. Fluorescent spectra revealed the presence of orange fluorescence with a maximum emission at ~595nm on the carapace of these ostracods, while scanning electron microscopy revealed a morphologically diverse microbial community covering the entire carapace of these ostracods. Pyrosequencing and cyanobacterial-specific 16S rRNA sequencing reveals that this epibiont community is highly diverse and highly variable between individual ostracods. Many species of Cyanobacteria in the orders Oscillatoriales and Chroococcales, as well as other Proteobacteria and diatom chloroplast sequences, were identified using the cyanobacterial-specific primers. While no fluorescent proteins or phycoerythrin were detected in these ostracods, it is possible that the observed orange fluorescence is the result of carotenoid fluorescence from Cyanobacteria. The microbial consortium forms an epibiotic biofilm on the carapace of these ostracods whose functions are unknown.