Abstract
GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 26, GB1020, 15 PP., 2012
doi:10.1029/2011GB004040
Estimating net community production in the Southern Ocean based on atmospheric potential oxygen and satellite ocean color data
Estimating net community production in the Southern Ocean based on atmospheric potential oxygen and satellite ocean color data
Key Points- Estimating NCP from satellite ocean color data involves compounding uncertainties
- Seasonal cycles in APO can help constrain net community production
- APO data suggest NCP is 0.8?1.2 Pg C/Yr in the Southern Ocean south of 50S
INSTAAR, University of Colorado at Boulder, Boulder, Colorado, USA
Scripps Institution of Oceanography, University of California,San Diego, La Jolla, California, USA
Scripps Institution of Oceanography, University of California,San Diego, La Jolla, California, USA
Scripps Institution of Oceanography, University of California,San Diego, La Jolla, California, USA
Scripps Institution of Oceanography, University of California,San Diego, La Jolla, California, USA
Department of Geosciences, Princeton University, Princeton, New Jersey, USA
Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
The seasonal cycle of atmospheric potential oxygen (APO ? O2 + 1.1 CO2) reflects three seasonally varying ocean processes: 1) thermal in- and outgassing, 2) mixed layer net community production (NCP) and 3) deep water ventilation. Previous studies have isolated the net biological seasonal signal (i.e., the sum of NCP and ventilation), after using air-sea heat flux data to estimate the thermal signal. In this study, we resolve all three components of the APO seasonal cycle using a methodology in which the ventilation signal is estimated based on atmospheric N2O data, the thermal signal is estimated based on heat flux or atmospheric Ar/N2 data, and the production signal is inferred as a residual. The isolation of the NCP signal in APO allows for direct comparison to estimates of NCP based on satellite ocean color data, after translating the latter into an atmospheric signal using an atmospheric transport model. When applied to ocean color data using algorithms specially adapted to the Southern Ocean and APO data at three southern monitoring sites, these two independent methods converge on a similar phase and amplitude of the seasonal NCP signal in APO and yield an estimate of annual mean NCP south of 50?S of 0.8?1.2 Pg C/yr, with corresponding annual mean NPP of ?3 Pg C/yr and a mean growing season f ratio of ?0.33. These results are supported by ocean biogeochemistry model simulations, in which air-sea O2 and N2O fluxes are resolved into component thermal, ventilation and (for O2) NCP contributions.
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Received 14 January 2011; accepted 5 January 2012; published 8 March 2012.
Citation: (2012), Estimating net community production in the Southern Ocean based on atmospheric potential oxygen and satellite ocean color data, Global Biogeochem. Cycles, 26, GB1020, doi:10.1029/2011GB004040.
Source: http://dx.doi.org/10.1029/2011GB004040
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