This grant provides two years of continued support for the Reservoirs and Fluxes Directorate of the Deep Carbon Observatory (DCO). Led from the Department of Terrestrial Magnetism of the Carnegie Institution of Washington and the Ecole Nationale Supйrieure de Gйologie in Nancy, France, the Directorate is the division of the DCO dedicated to transforming our understanding of the distribution, abundance, and movement of Earth’s subsurface carbon. The group aims for important discoveries in five areas: degassing deep carbon through volcanic processes; degassing deep carbon through tectonic and other diffuse processes; origin, age, and depth of diamonds and mineral inclusions found within them; fluid dynamics of carbon transport in volcanoes and global circulation of carbon from Earth’s surface to its core; and chemical forms, mineral hosts, and reactions of carbon moving between reservoirs. Collaborating with national volcano observatories, group members will also begin to establish the first global network for direct measurement of volcanic carbon dioxide flux and produce a new database on eruptions and volcanic gases. Expected outcomes from this grant include new instruments, databases, models, insights, and several doctoral and postdoctoral researchers trained in deep carbon research.