Through the biological activity, marine dissolved inorganic carbon is transformed into different types of biogenic carbon available for export to the ocean interior, including particulate organic carbon (POC), dissolved organic carbon (DOC), and particulate inorganic carbon (PIC). Each biogenic carbon pool has a different export efficiency that impacts the vertical carbon gradient and drives natural air-sea CO₂ exchange. In the Southern Ocean (SO), which accounts for ~40% of the modern anthropogenic ocean carbon sink, it is unclear how the production of each biogenic carbon pool affects the background, and natural air-sea CO₂ exchange. Based on 93 independent observations of the seasonal cycle from 54 biogeochemical profiling floats, we quantify how biological processes influence the seasonal SO carbon sink. We find strong meridional variability in seasonal biological carbon production with enhanced POC production in the subantarctic and polar Antarctic sectors and enhanced DOC production in the subtropical and sea-ice-dominated sectors. PIC production peaks between 47 °S and 57 °S near the “great calcite belt”. Relative to an abiotic SO, seasonal organic carbon production enhances CO₂ uptake by 1.60 ± 0.37 Pg C yr^-1 while seasonal PIC production diminishes CO₂ uptake by 0.15 ± 0.11 Pg C yr^-1. Without organic carbon production, the SO would be a seasonal CO₂ source to the atmosphere.