Synthetic periphyton as a model system to understand species dynamics in complex microbial freshwater communities

Abstract

AbstractPhototrophic biofilms, also known as periphyton, are microbial freshwater communities that drive crucial ecological processes in streams. Understanding species dynamics in such communities is challenging due to their complexity, yet fundamental to gain insights into the mechanisms of biofilm development and adaptation, such as under conditions of climate change and chemical pollution. To address this challenge, we rationally designed a workflow, based on knowledge about natural periphyton formation. This workflow allowed us to build a fully defined but diverse, stable and highly reproducible synthetic periphyton model system consisting of at least 22 phototrophic species. We demonstrate the ability to monitor microbial dynamics at the species level during periphyton development and how their abundances are impacted by stressors such as increased temperature and a herbicide, singly and in combination. Importantly, by knowing the exact composition of the periphyton we show that, besides specific sensitivities to stressors, species interactions are a major driver for community diversity.