A novel estimate of ocean oxygen utilisation points to a reduced rate of respiration in the ocean interior
The Apparent Oxygen Utilisation (AOU) is a classical measure of the amount of oxygen respired in the ocean's interior. We show that AOU systematically overestimates True Oxygen Utilisation (TOU) in 6 coupled circulation-biogeochemical ocean models. This is due to atmosphere–ocean oxygen disequi...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-11-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/10/7723/2013/bg-10-7723-2013.pdf |
| Summary: | The Apparent Oxygen Utilisation (AOU) is a classical measure of the amount of
oxygen respired in the ocean's interior. We show that AOU systematically
overestimates True Oxygen Utilisation (TOU) in 6 coupled
circulation-biogeochemical ocean models. This is due to atmosphere–ocean
oxygen disequilibria in the subduction regions, consistent with previous
work. We develop a simple, new, observationally-based approach which we call
Evaluated Oxygen Utilisation (EOU). In this approach, we take into account
the impact of the upper ocean oxygen disequilibria into the interior,
considering that transport takes place predominantly along isopycnal
surfaces. The EOU approximates the TOU with less than half of the bias of AOU
in all 6 models despite large differences in the physical and biological
components of the models. Applying the EOU approach to a global observational
dataset yields an oxygen consumption rate 25% lower than that derived
from AOU-based estimates, for a given ventilation rate. |
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| ISSN: | 1726-4170 1726-4189 |