Walcker R. auteur aut IRD Corenblit D. auteur aut IRD Julien F. auteur aut IRD Martinez Jean-Michel auteur aut IRD Steiger J. auteur aut IRD text journalArticle eng text/pdf born digital access Better understanding the fate of the atmospheric carbon (C) captured by plant photosynthesis is essential to improve natural C flux modelling. Soils are considered as the major terrestrial bioreactor and repository of plant C, whereas channel networks of floodplain rivers collect and transport, throughout the aquatic continuum, a significant part of plant primary production until its export through outgassing or sequestration in marine sediments. Here, we show that river meandering in forested floodplains is a crucial and widely overlooked Earth surface process promoting C fluxes from the atmosphere to the aquatic continuum, via the floodplain vegetation. Over a recent period of 35 years (1984-2019), we quantified those C fluxes in one of the most active meandering rivers on Earth, the Ucayali River, Peru, South America. We used map time series combined with above-ground forest C data to derive the amount of C that is annually captured by the growing floodplain vegetation within the active meander belt, as well as exported to the aquatic continuum by lateral channel erosion. We found that the annual building and erosion of forested floodplain areas was nearly balanced over time with 19.0 +/- 7.7x10(3) ha(-1) yr(-1) and 19.8 +/- 6.7x10(3) ha(-1) yr(-1), respectively. While growing forests within the active meander belt annually captured 0.01 +/- 0.05x10(6) Mg C yr(-1), lateral channel erosion provided the nearly 100-fold amount of C to the river channel and its stream flow, i.e. 0.9 +/- 0.4x10(6) Mg C yr(-1). Our findings revealed that the migration of the Ucayali River channel provided nearly 10-times more lignified C per unit area to the aquatic continuum(44.7 +/- 21.4Mg C ha(-1) yr(-1)) than non-meandering central Amazonian floodplains do. Together, these findings point to the importance of quantifying the overall contribution of meandering rivers to natural C fluxes worldwide. specialized Amazon Carbon Floodplain Forest age Meandering river Remote sensing PEROU AMAZONIE 062 021 126 776 146056 [10 ] 2021 0048-9697 https://www.documentation.ird.fr/hor/fdi:010081453 10.1016/j.scitotenv.2021.146056 0048-9697 [F B010081453] https://www.documentation.ird.fr/hor/fdi:010081453 https://www.documentation.ird.fr/intranet/publi/2021-06/010081453.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2021-06-15 2025-02-24 fdi:010081453 fre