This meeting will provide a forum for discussing of the role of both on- and off-axis hydrothermal fluxes in regulating ocean biogeochemistry and the Earth system, and the feedbacks between the Earth’s surface environment and hydrothermal fluxes. The meeting will consider all timescales from the modern (e.g., insights and outstanding questions based on recent GEOTRACES work) through to the role of hydrothermal systems on the early Earth and exoplanets (e.g., waterworlds). We aim to bring together researchers from diverse research fields with the hope of initiating new interdisciplinary research.