Disturbance During Biofilm Community Succession Promotes Diversity and Cooperation

Microbial communities have been used as a test bed for fundamental theoretical ecology for over a century. Model communities are often contrived rather than the product of community succession and are usually limited to a low numbers of taxa. Here we report on the successful use of microbial fuel cells as tractable and fully specified ecological microcosms. These systems allowed the investigation of interactions between disturbance, diversity and productivity in rich anaerobic biofilms. Productivity-diversity and diversity-disturbance relationships have found widespread application in rainforest ecology, conservation and biodiversity management. These conceptual frameworks have yet to be systematically applied to microbial community succession. Here we combine extended biofilm cultures using microbial fuel cells with next generation sequencing methods to reveal previously unseen ecological processes in anaerobic biofilms. Diversity-disturbance and productivity-diversity relationships can be used to explain dynamic changes in the structure of MFC communities. Biofilm succession is guided onto either a generalist-dominated or a cooperative specialist trajectory depending on the level of disturbance taking place within the community. These interactions show remarkable symmetry with findings from macro-scale communities such as grasslands, coral reefs and rainforests.