Submarine Canyon Oxygen Anomaly Caused by Mixing and Boundary‐Interior Exchange

Closely spaced CTD stations showed elevated oxygen within Monterey Submarine Canyon. Anomalously high (2–5 μmol kg −1 ) dissolved oxygen was found between 600–1,100 m in the O 2 minimum, co‐located with a turbulence hotspot caused by convergence of upcanyon, semidiurnal internal tidal energy flux. Furthermore, the oxygen anomaly extended >10 km downcanyon at the same depth and isopycnals of a previously identified intrusion predicted from buoyancy conservation. We show that dissolved oxygen and fine suspended particles act as independent tracers to (a) validate previous microstructure observations of intense turbulence extending >400 m above the bed (mab) at the canyon hotspot, and (b) track boundary‐interior exchange driven by mixing in the form of isopyncal‐spreading of anomalies away from a near‐boundary source. This study demonstrates the use of oxygen, commonly measured with shipboard profiling, as a tool for tracking mixing and lateral dispersal.