Atmospheric dissolved organic carbon deposition closes a missing link in the global terrestrial carbon cycle

Atmospheric organic carbon deposition acts as both a critical terminal sink for air pollutants and a substantial nutrient subsidy to terrestrial ecosystems. A substantial fraction of deposited atmospheric organic carbon reaches terrestrial ecosystems as dissolved organic carbon through precipitation and canopy throughfall. However, this atmospheric dissolved organic carbon subsidy remains missing from current global carbon budgets. Here, we reconstruct global dissolved organic carbon deposition (1980–2020) by integrating machine learning with stable and radiocarbon isotope constraints. We estimate a global deposition flux of 612 Tg C yr⁻¹, rivaling global land-to-ocean export. Crucially, canopy interception dominates ( ~ 52% of the global flux) yet is systematically underestimated by chemical transport models. We further demonstrate that deposition has decoupled from rising precursor emissions, governed instead by shifting meteorological regimes. This persistent atmospheric input partially offsets lateral hydrological carbon losses, highlighting the atmosphere as an active conveyor linking atmospheric processes and terrestrial carbon cycling. Canopy interception dominates atmospheric deposition of dissolved organic carbon, according to a process-explicit reconstruction of dissolved organic carbon utilizing carbon isotope data and machine learning.