Fraction of surface NPP exported as sinking particulate organic carbon to the deep ocean, sequestering CO₂ for centuries. Export-efficiency e_ratio = export/NPP ≈ 0.1–0.3; twilight-zone remineralisation controls depth of sequestration.
Fraction of surface NPP exported as sinking particulate organic carbon to the deep ocean, sequestering CO₂ for centuries. Export-efficiency e_ratio = export/NPP ≈ 0.1–0.3; twilight-zone remineralisation controls depth of sequestration.