In this project we conducted a infield comparative study of bacterial communities associated to the purple gorgonian P. clavata in the Mediterranean Sea collected at different geographic locations and depth, showing contrasting levels of anthropogenic disturbance and different health status. Our rationale considers the fact that alteration of the coral holobiont may be investigated as a proxy of coral health status and sensitivity to nonresident pathogens. The objective of this study was to assess whether anthropogenic influence affect the composition of the bacterial holobiont and if this could be linked to disease outbreaks.