Soil is teeming with bacteria and other microbes that drive the flow of nutrients on Earth, absorbing and releasing greenhouse gases like carbon dioxide (CO2). This nutrient flow depends on the ways different microbial species interact with each other and with other organisms including plants. As plant roots grow through soil, they release chemicals that feed the surrounding microbes in the region around roots known as the rhizosphere. In the rhizosphere, microbes also interact with each other by sharing micronutrients such as vitamins, but how micronutrient sharing impacts microbial community dynamics remains unknown. To study the links between microbial growth, micronutrient sharing, and carbon release, researchers will assemble a model community of bacteria within customized chambers that mimic the chemical environment of the rhizosphere. This novel experimental system will serve as a model for other scientists studying similar processes. Results of this study will be used to test existing computational models that predict how soil microbial communities influence carbon cycling. In addition to training students and postdoctoral scholars, this project will involve local 6th and 7th graders and their teachers to bring authentic research experiences to classrooms and to train the next generation of scientists. Microbial community assembly in the rhizosphere is shaped by microbial interactions, functional traits, and changing root chemistry. These factors modulate carbon us