Eddy-Modulated Internal Waves and Mixing on a Midocean Ridge

Mesoscale eddies are ubiquitous in the World Ocean and dominate the energy content on subinertial time scales. Recent theoretical and numerical studies suggest a connection between mesoscale eddies and diapycnal mixing in the deep ocean, especially near rough topography in regions of strong geostrophic flow. However, unambiguous observational evidence for such a connection has not yet been found, and it is still unclear what physical processes are responsible for transferring energy from mesoscale to small-scale processes. Here, the authors present observations demonstrating that finescale variability near the crest of the East Pacific Rise is strongly modulated by low-frequency geostrophic flows, including those due to mesoscale eddies. During times of strong subinertial flows, the authors observed elevated kinetic energy on vertical scales