Unifying framework reveals importance of dissolved fluxes in ocean biological carbon pump

The ocean biological carbon pump sequesters carbon from the atmosphere through diverse pathways, including gravitational settling, physical transport, and organism vertical migration. However, robust assessments of its magnitude remain challenging. Traditional approaches treat individual pathways separately, risking double counting fluxes when combining estimates, fail to capture the full range of spatio-temporal scales involved (from kilometers to thousands, hours to years), and focus on particulate carbon while overlooking dissolved fluxes. Here, we apply a unified framework quantifying all pathways simultaneously to a high-resolution (3 km) idealized model of the North Atlantic resolving seasonal, physical, and biological dynamics across scales, from regional biomes to fine-scale fronts. We show that carbon sequestration is dominated by the gravitational pump (~ 70%), followed by physical (17–25%) and migrant (5–10%) pumps. Remarkably, carbon sequestration by the physical and migrant pumps is driven by dissolved fluxes—dissolved organic carbon transport and zooplankton respiration—which together account for over 20% of biological pump sequestration. Our findings underscore how unresolved dissolved fluxes and spatio-temporal variability —particularly physical pump fine-scale variability— can bias current estimates of the biological carbon pump, and call for a paradigm shift toward integrative approaches combining next-generation observations with process-resolving models.