Premium
Is AOU a good measure of respiration in the oceans?
Author(s) -
Ito T.,
Follows M. J.,
Boyle E. A.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl020900
Subject(s) - thermocline , oxygen , respiration , atmosphere (unit) , oceanography , apparent oxygen utilisation , environmental science , latitude , surface water , atmospheric sciences , remineralisation , biogeochemical cycle , geology , environmental chemistry , chemistry , biology , meteorology , inorganic chemistry , botany , physics , organic chemistry , geodesy , fluoride , environmental engineering
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.