Professor Seth John of The University of Southern California and Growing Oceans introduces a new marine carbon dioxide removal pathway that has the potential to scale at low cost: Nitrogen Fixation for Phytoplankton Carbon (NFix).  This new pathway catalyzes production of additional ocean nutrients by iron addition, potentially mitigating concerns about ’nutrient robbing’ associated with traditional Ocean Iron Fertilization (OIF) methods. Dr. John discusses key features of this pathway, “natural experiment” studies of iron input from South Pacific hydrothermal vents, technical challenges to safely scaling the process, and the team's collaboration with the Kingdom of Tonga.