Feng Dongyu, Tan Zeli, Pinel Sebastien, Xu Donghui, Amaral João Henrique Fernandes, Fassoni-Andrade Alice César, Bonnet Marie-Paule, Bisht Gautam
Atmospheric, Climate, & Earth Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
Centre of Education and Research on Mediterranean environments (CEFREM), University of Perpignan Via Domitia (UPVD), Perpignan, Perpignan, France.
Nat Commun. 2025 Apr 2;16(1):3148. doi: 10.1038/s41467-025-57495-1.
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 yr), we estimate the trapping of 77.3 ± 13.9 Mt (or 6.1 ± 1%) of the Amazon River sediment by the Amazon/Solimões 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.
亚马逊河携带来自安第斯山脉的大量沉积物，其中大部分沉积在其洪泛平原。然而，在精细的时空尺度上准确量化沉积物汇仍然具有挑战性。在这里，我们提出了一个高分辨率水动力-沉积物模型，以模拟亚马逊河/索利蒙伊斯河代表性洪泛平原中的沉积物沉积。研究发现，该过程是由洪水淹没、亚马逊河中的悬浮沉积物浓度以及洪泛平原水动力共同驱动的，并且与淹没水平的相关性较弱。通过扩大沉积物沉积速率（1.33±0.24千克/米·年），我们估计亚马逊河/索利蒙伊斯河洪泛平原每年截留77.3±13.9百万吨（或6.1±1%）的亚马逊河沉积物。随着时间的推移，大面积的森林砍伐将降低洪泛平原的截留效率，加剧下游河流的淤积。此外，我们表明，与沉积物相关的有机碳的沉积在促进亚马逊地区二氧化碳和甲烷排放方面作用较小。
