Synthetic periphyton as a model community to examine species dynamics in complex microbial consortia

Phototrophic biofilms, also known as periphyton, drive crucial ecosystem processes and are subject to alterations due to a multitude of biotic and abiotic factors. In this context, understanding species dynamics in periphyton is a fundamental, yet challenging, requirement to accurately predict outcomes on functions and properties of complex communities. To address this challenge, we developed a workflow applying rational design based on existing knowledge on natural periphyton, to successfully obtain a stable, diverse and highly reproducible synthetic periphyton. We show that by using our synthetic community, with a known microbial composition, we are able to monitor dynamics of single species during periphyton development and their specific response to stressors such as increased temperature and herbicides. Importantly, we clearly demonstrate that these responses are mainly driven by species interactions and how they link to changes of community function and structure. Our synthetic periphyton is a powerful tool to perform mechanistic studies on periphyton structural and functional responses, as well as on species propagation, to any biotic and abiotic stressors and their combinations.