Bacteria and other microbes are essential to human life and industry, catalyzing key biogeochemical cycles, cleaning up toxic pollution, and causing or curing disease. Microbial ecology, the study of microbes’ relationships with one another and their environment, has benefited tremendously from new DNA sequencing technology. However, DNA sequencing data alone cannot answer important questions in microbial ecology. It remains particularly difficult to discover interactions between bacteria. I will discuss an innovative approach that combines DNA sequencing data with biogeochemical modeling and clustering techniques to infer the presence of large number of consortia, a special kind of interacting group of bacteria, in a natural ecosystem. Only a few consortia were previously known, so an abundance of consortia could have vast implications for our understanding of the role of bacteria in global environmental cycles and for our use of bacteria in industrial applications.