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1605056 
Journal Article 
Simulated 21st century's increase in oceanic suboxia by CO(2)-enhanced biotic carbon export 
Oschlies, A; Schulz, KaiG; Riebesell, Ulf; Schmittner, A 
2008 
Yes 
Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224 
22 
4 
n/a-n/a 
WOS:000260991700001 
The primary impacts of anthropogenic CO2 emissions on marine
biogeochemical cycles predicted so far include ocean acidification, global warming induced shifts
in biogeographical provinces, and a possible negative feedback on atmospheric CO2 levels by CO2-
fertilized biological production. Here we report a new potentially significant impact on the
oxygen-minimum zones of the tropical oceans. Using a model of global climate, ocean circulation,
and biogeochemical cycling, we extrapolate mesocosm-derived experimental findings of a pCO(2)-
sensitive increase in biotic carbon-to-nitrogen drawdown to the global ocean. For a simulation
run from the onset of the industrial revolution until A.D. 2100 under a ""business-as-usual''
scenario for anthropogenic CO2 emissions, our model predicts a negative feedback on atmospheric
CO2 levels, which amounts to 34 Gt C by the end of this century. While this represents a small
alteration of the anthropogenic perturbation of the carbon cycle, the model results reveal a
dramatic 50% increase in the suboxic water volume by the end of this century in response to the
respiration of excess organic carbon formed at higher CO2 levels. This is a significant expansion
of the marine ""dead zones'' with severe implications not only for all higher life forms but
also for oxygen-sensitive nutrient recycling and, hence, for oceanic nutrient inventories.