This project leverages available AUV Sentry and R/V Atlantis time to implement and test new methods for quantifying heat and fluid fluxes at deep-sea hydrothermal vents. Simultaneous AUV-mounted flow velocity and temperature gradient measurements will be obtained and corrections for vehicle motion will be used to compute flux in/out of a control volume that surrounds the known venting. At Main Endeavour Field on the Juan de Fuca Ridge, the control volume estimates will be compared to the 2000 FlowMow results to better delimit contributions of diffuse flow. At Ashes hydrothermal field on Axial Volcano, a series of surveys at 5 m height will help test the new method for measuring diffuse flow from an AUV. These near-bottom measurements will be validated and synthesized with direct measurements of diffuse and focused flow provided by camera systems deployed for a separate project. Simultaneous measurement of different scales (very near-bottom and control volumes of 100'm on each side) of heat flux and turbulence within the hydrothermal effluent is an expected outcome. The method developed will provide the oceanographic community with new capabilities for quantifying fluxes with AUVs at hydrothermal vents and possibly in other environments as well, including cold seeps and natural or artificial hydrocarbon leaks.
