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Submarine Canyon Oxygen Anomaly Caused by Mixing and Boundary-Interior Exchange
  • Erika E McPhee-Shaw,
  • Eric Kunze,
  • James B. Girton
Erika E McPhee-Shaw
Western Washington University, Western Washington University

Corresponding Author:[email protected]

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Eric Kunze
Northwest Research Associates, Northwest Research Associates
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James B. Girton
University of Washington, University of Washington
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Abstract

Closely spaced CTD stations showed elevated oxygen within Monterey Submarine Canyon. Anomalously high (2 to 5 umol kg -1) dissolved oxygen was found between 600-1100m in the O2 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 1) validate previous microstructure observations of intense turbulence extending ~> 400 mab at the canyon hotspot, and 2) 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.