Using an expanding Southern Ocean fleet of biogeochemical Argo (BGC-Argo) floats, we developed a novel approach to estimate annual net community production (ANCP) by integrating subsurface oxygen drawdown from all available BGC-Argo oxygen profiles. Our results suggest that, on average, 14% of remineralization occurs between 500 and 1000 m and 15% occurs between the euphotic depth and 100 m. Using the improved methodology, we estimated total basin-integrated ANCP in the Southern Ocean to be 3.89 GT C year^-1 suggesting a more important role for the Southern Ocean in regulating oceanic carbon storage, atmospheric CO₂ exchange and climate than previously assumed.