Is AOU a good measure of respiration in the oceans?
Article first published online: 14 SEP 2004
Copyright 2004 by the American Geophysical Union.
Geophysical Research Letters
Volume 31, Issue 17, September 2004
How to Cite
2004), Is AOU a good measure of respiration in the oceans? Geophys. Res. Lett., 31, L17305, doi:10.1029/2004GL020900., , and (
- Issue published online: 14 SEP 2004
- Article first published online: 14 SEP 2004
- Manuscript Accepted: 20 AUG 2004
- Manuscript Received: 1 JUL 2004
 Apparent Oxygen Utilization (AOU) is widely used to infer respiration in the oceans by assuming that surface oxygen concentration is close to saturation with the overlying atmosphere. However, significant disequilibrium of oxygen has been observed in high latitude surface oceans where the deep waters are formed. We explicitly calculate True Oxygen Utilization (TOU) in a global ocean physical-biogeochemical model to evaluate the ability of AOU to represent respiration. We find significant differences between AOU and TOU in the deep waters, suggesting a systematic overestimation of respiration when inferred from AOU. The surface heat flux and the entrainment of thermocline waters together drive the surface undersaturation of oxygen in the regions of water mass formation, and their influences are significantly enhanced by sea ice cover at high latitudes.