Copepod-associated microbiome responses to organophosphate ester plasticizers in the ocean
The impact of organic contaminants, including plastics, on open ocean ecosystems remains poorly quantified, largely due to limited in situ impact assessment and the lack of field sentinel species. The copepod Paracartia grani, exposed in laboratory experiments to environmentally relevant concentrations of organophosphate esters (OPEs), a prevalent class of plasticizers and flame retardants, underwent significant alterations in its associated bacterial communities, paralleled by a decrease in the copepod fecundity. Specially, we observed an increase in the abundances of Enterobacterales and Pseudomonadales in the copepod-associated microbiome. Consistently, field OPE concentrations in seawater along a latitudinal Atlantic Ocean transect (from 40 oN to 52 oS) were significantly correlated with Enterobacterales genera (Vibrio, Photobacterium, Pseudoalteromonas) in copepod-associated microbiomes, but not in particle-attached or free-living microbial fractions. Our findings suggest that OPE exposure and bioaccumation in copepods, disrupts their microbiomes, and likely affects their physiological performance and biogeochemical role. This study highlights copepod-associated bacteria as sensitive biosensors for detecting plasticizer pollution in marine ecosystems. As such, copepod-associated microbiome analysis emerges as a novel monitoring tool for exposure to organic contaminants and their impacts in marine ecosystems.