Unit Affiliation: Marine and Polar Geophysics, Lamont-Doherty Earth Observatory (LDEO)
The PI's request funding to develop a pair of camera systems that are specifically designed to use OPV (VentCam) and DFV (Diffuse Effluent Measurement System (DEMS)) to measure the velocities of focused and diffuse hydrothermal flows in these environments. The VentCam system will use OPV to perform time-series velocity measurements on black smoker fluids using a high-speed, high resolution camera with automatic panning that maintains the flow in the field-of-view during sulfide chimney growth. The DEMS will measure diffuse fluid velocities using a camera attached at a fixed distance from a background specially designed for DFV calculations. Simultaneous temperature measurements by thermocouples placed in high-temperature vent orifices as well as low-temperature loggers coupled to the DEMS will help constrain the partitioning of diffuse and focused heat fluxes and the amount of crustal cooling attributable to axial venting. Measuring the rates at which hydrothermal fluids exit the crust, and how those rates change over time, is critical for understanding these systems and the complex linkages between their component parts. Such measurements can provide information about the structure of permeability in the subseafloor, the geometry of hydrothermal circulation patterns, fluxes of heat and chemicals exchanged with the overlying ocean, and the potential productivity of subseafloor ecosystems. Broader impacts: Knowledge gained using these tools will improve our understanding of hydrothermal fluid fluxes and their contribution to a variety of chemical, biological and physical processes. The project will support two early career scientists who were responsible for developing the optical methods to be used by these imaging systems. The Mentoring plan for the post-doc is well described and likely to result in successful development of the researcher during the projects lifetime. When developed and tested, the instruments have potential for longer-term time series if connected to regional seafloor cabled observatories like the Regional Serial Nodes observatory under development on the Juan de Fuca Ridge.