Data and Code for Atmospheric Deposition Dominates Land to Ocean Nitrogen Flow

Anthropogenic nitrogen (N) mobilization severely perturbs global biogeochemical cycles1-4. The land-to-ocean aquatic continuum (LOAC) serves as a critical conveyor and reactor for excess nitrogen, yet the magnitude and drivers of its fluxes remain poorly quantified5. Here, integrating ~86,400 observational records with machine learning and high-resolution deposition modeling, we present the first data-driven reconstruction of global LOAC N dynamics (1990–2020). We reveal a continental-scale redistribution of pollution hotspots as headwaters nitrate (NO3−) concentrations declined significantly in the U.S. and Europe (−5.00 to −9.54 μg L−1 yr−1) but surged in China and India (+5.24 to +11.8 μg L−1 yr−1). Crucially, atmospheric deposition, not fertilizer, dominates LOAC N fluxes, driving stable riverine dissolved inorganic nitrogen (DIN) export (mean: 23.2 ± 1.7 Tg N yr⁻¹). This flux represents only 6.9% of continental N inputs, underscoring strong terrestrial-aquatic retention. Projections to 2060 under SSP1-2.6 indicate declining LOAC N fluxes despite rising continental inputs, primarily attributable to NOx emission controls reducing oxidized N (OXN) deposition. Our findings redefine atmospheric deposition as the dominant driver of global LOAC N transport and establish targeted emission abatement as a key lever for aquatic and coastal environment protect and Sustainable Development Goals advance.