Characterizing space-time patterns of diffuse hydrothermal flow: Application of heat-as-a-tracer methods to the Lucky Strike hydrothermal field

Hot water discharging from the seafloor carries heat and metals to the ocean and from the Earth’s crust. A large part of this discharge occurs as warm fluids that seep out of the seafloor in ways that are difficult to measure. Quantifying the heat and chemical element flow is a long-standing and challenging problem. This project will address this important problem by adapting ground-water seepage measurement methods from shallow water to deep sea environments. This project will fund construction of eleven new instruments and deploy them for a year at the Mid-Atlantic Ridge. Data from these instruments will help to constrain the rates and spatial patterns of warm fluids. The data will be used to better understand how diffuse fluids are related to oceanographic, geologic, and biological processes. Mid-ocean ridge hydrothermal systems play a fundamentally important role in the exchange of heat and mass between the ocean and lithosphere. However, a large portion of hydrothermal flow occurs through diffuse discharge zones where warm fluids seep out of the seafloor in ways that are difficult to detect and measure. Diffuse discharge zones, due to their relatively low fluid temperatures and velocities, also provide critical habitat for the subsurface microbial biosphere. Quantifying thermal and geochemical fluxes in diffuse discharge zones is a long-standing and challenging problem that this work will address by adapting instrumentation and techniques developed for measuring weak flow in shallow water environments to the measurement of diffuse hydrothermal flow in deep sea environments. This project will fund eleven new instruments and deploy them in a multidisciplinary experiment in collaboration with scientists from the seafloor observatory at the Tour Eiffel vent site on the Mid-Atlantic Ridge. Data from the instruments will constrain diffuse flux and spatial patterns at the vent site, and integrated with contemporaneously acquired observatory data to investigate the relationship of diffuse flow to oceanographic, geologic, and biological processes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.