Feng D. Y. auteur aut IRD Tan Z. L. auteur aut IRD Pinel S. auteur aut IRD Xu D. H. auteur aut IRD Amaral J. H. F. auteur aut IRD Fassoni-Andrade A. C. auteur aut IRD Bonnet Marie-Paule auteur aut IRD Bisht G. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The Amazon River carries enormous amounts of sediment from the Andes mountains, much of which is deposited in its floodplains. However, accurate quantification of the sediment sink at fine spatiotemporal scales is still challenging. Here, we present a high-resolution hydrodynamic-sediment model to simulate sediment deposition in a representative Amazon/Solimões floodplain. The process is found to be jointly driven by inundation, suspended sediment concentration in the Amazon River, and floodplain hydrodynamics and only weakly correlated with inundation level. By upscaling the sediment deposition rate (1.33 +/- 0.24 kg m(-2) yr(-1)), we estimate the trapping of 77.3 +/- 13.9 Mt (or 6.1 +/- 1%) of the Amazon River sediment by the Amazon/Solim & otilde;es floodplains every year. Widespread deforestation would reduce the trapping efficiency of the floodplains over time, exacerbating downstream river aggradation. Additionally, we show that the deposition of sediment-associated organic carbon plays a minor role in fueling carbon dioxide and methane emissions in the Amazon. specialized AMAZONIE AMAZONE COURS D'EAU SOLIMOES COURS D'EAU 064 062 020 16 1 3148 [12 p.] 2025 https://www.documentation.ird.fr/hor/fdi:010093391 10.1038/s41467-025-57495-1 [F B010093391] https://www.documentation.ird.fr/hor/fdi:010093391 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-05/010093391.pdf IRD - Base Horizon / Pleins textes 2025-05-14 2025-05-14 fdi:010093391 fre