Plasticity of the Anemonia viridis microbiome in response to different levels of anthropogenic impacts. undefined

Despite their recognized primary importance, marine coastal ecosystems around the globe are currently under threat, being subject to continuous local and global anthropogenic stressors. In this frame, understanding the response of coastal habitat-forming species to multiple stressors and their resilience is fundamental for the sustainable management of coastal ecosystems. In the present study, to provide some glimpses in this direction, we explored the response of the Anemonia viridis-associated microbiome to the combined anthropogenic stressors, which typically affect the Mediterranean coastal sites. To this aim, two case studies have been carried out, the first in the Riccione coastal site (Italy, Center Mediterranean) and the second at Cap de Creus (Spain, North-western Mediterranean), where the A. viridis microbiome was assessed both under high-impact and low-impact conditions. According to our findings, the A. viridis microbiome showed a relevant degree of plasticity in response to combined anthropogenic stressors, with changes that also mirrored variations in the surrounding seawater, thus indicating a close connection with the environment, from which potential symbiotic partners are selected. However, this potentially adaptive process also has a limitation, as observed in the high-impact site at Cap de Creus, where A. viridis-associated microbiome appeared completely unstructured, as demonstrated by an increased dispersion, according to the Anna Karenina principle. This raises the question about the limits of the resilience of the A. viridis-associated microbiome under anthropic treats, as well as of the anthropic factors driving to the observed dysbiosis changes. This work was carried out in the context of the “Controlling Microbiomes Circulations for Better Food Systems” (CIRCLES) project, which was funded by the European Union's Horizon 2020 research and innovation program under grant agreement no. 818290.