Unexpected Consequences of River Engineering on the Carbon Cycle

Rivers around the world have been heavily engineered, and these man-made changes are affecting important biogeochemical cycles. play a key role in global carbon cycle, by mobilizing organic from land delivering it to oceans. River engineering techniques, like levees that prevent flooding, change way is cycled through rivers, but difficult identify quantify changes. Shen et al. (2021) were able river fluxes induced bank stabilization Mississippi River. The authors compared age distribution of modern sediment old deposited before construction extensive levee systems. They found significantly reduces amount time spends system being exported Gulf Mexico. As result, less oxidized CO2 more ocean, ultimately reducing atmospheric CO2. This study highlights an effect anthropogenic activity on should be considered cycle models.