Surgeonfish feces increase microbial opportunism in reef-building corals

A number of marine invertebrates and fishes were suspected to vector and or facilitate the enrichment of microbes in corals. In this study, we investigated whether the widely distributed surgeonfish Ctenochaetus striatus could vector and/or facilitate the enrichment of bacteria in the coral species Porites lobata. In addition, as P. lobata colonies experience high rates of predation by parrotfishes in the field, we also investigated the interactive effects of artificial wounding and C. striatus feces deposition on coral microbiomes.For that, we used a factorial experimental design, including four treatments: a control treatment with untreated P. lobata corals (named control), a treatment where corals were artificially wounded (named wound), a treatment where a fecal pellet of C. striatus was disposed on each coral fragment (named feces) and a treatment combining wounding and fecal pellet deposition (feces+wound). Samples were collected at 3 time points (T3, T15h and T48h) to track the temporal change in unwounded and wounded coral microbiomes and to test the potential for C. striatus to vector microbes in corals. Additionnaly, one water sample was collected in each tank (n=2 tanks per treatment, 8 tanks total) at the end of each timepoint.