Reverse weathering is a chemical process that forms clay minerals from dissolved silica and positively charged ions in marine sediments. This process is important because it impacts ocean pH, the availability of important metals (e.g. iron, lithium), and the long-term carbon cycle. In this project, the researchers plan to use stable and radioactive silicon isotopes to track reverse weathering processes in sediments of the Mississippi River Plume. The research includes laboratory and ship-based experiments exploring the role of microbial activity in sediment silicon cycling and reverse weathering. The experiments will also study how the presence or absence of oxygen and different sediment types influence these processes. The project will produce novel data and key insights about the cycling of silicon in marine sediments. Education and outreach activities focus on training the next generation of scientists at multiple levels. These include experiential learning activities for college undergraduates and training for a graduate student. This project will also provide two opportunities for high school students: 1) support scholarships for students to take an immersive six-week marine science class offered at the Dauphin Island Sea Lab and 2) provide support for high school students in rural Missouri to visit the Mobile Bay ecosystem where they will be introduced to marine science. Reverse weathering (RW) reactions are the collection of early diagenetic processes which produce