Carbon sequestration in tropical meandering rivers

Lateral activity and morphological evolutions of fluvial corridors play an active role in the river carbon cycle that is not completely understood so far. Organic carbon (OC) is produced and conveyed by river dynamics, but a quantification of OC sequestration from river systems is still lacking.
By combining stochastic processes and deterministic modeling for the meandering evolution, we develop a minimalistic model to evaluate the amount of carbon moved by tropical meandering rivers through the reworking of riverbed and riparian vegetation. The model assess the eroded area (by river sinuosity) and couples it with satellite-based data of vegetation carbon density. We assess the carbon sequestration in riparian zone of six fluvial reaches of the Amazon basin, and test the results with satellite-based data of vegetated area lost in the same regions. The process of continuous rejuvenation of the riparian community, due to uprooting of trees by the stream followed by recolonization, allows the riparian zone to produce more OC compared to an equivalent riparian vegetated area not subjected to flood disturbances and lateral erosion. This study shows that river carbon sequestration is closely connected to the river activity and is negatively affected by the anthropogenic activities, such as damming and mining.