Top-down processes drive taxonomic and phylogenetic diversity in a model aquatic microbial community

While the relative importance of bottom-up and top-down processes intructuring patterns of aquatic taxonomic diversity has been widely explored for many taxa, the response of aquatic microbial communities to bottom-up: top-down processes is not well understood. Further, studies of bottom-up: top-down processes in aquatic systems often focus on taxonomic diversity, leaving the response of other components of diversity (e.g., phylogenetic diversity) less clear. We used the model aquatic food web found in leaves of the pitcher plant Sarracenia purpurea to explore the influence of bottom-up: top-down processes on patterns of bacterial taxonomic and phylogenetic alpha- and beta-diversity. To explore the status of Wyeomyia smithii mosquito larvae as a prospective keystone predator of bacteria in this system, we developed two experiments where we manipulated resource level and the abundance of the top predator, W. smithii, in the presence or absence of intermediate consumers.