Open AccessUnexpected Consequences of River Engineering on the Carbon Cycle
Author(s) -
Repasch Marisa
Publication year - 2021
Publication title -
agu advances
Language(s) - English
Resource type - Journals
ISSN - 2576-604X
DOI - 10.1029/2021av000402
Subject(s) - carbon cycle , total organic carbon , biogeochemical cycle , environmental science , levee , carbon fibers , sediment , hydrology (agriculture) , earth science , geology , environmental chemistry , ecology , ecosystem , chemistry , geomorphology , materials science , geotechnical engineering , composite number , composite material , biology
Rivers around the world have been heavily engineered, and these man‐made changes are affecting important biogeochemical cycles. Rivers play a key role in the global carbon cycle, by mobilizing organic carbon from land and delivering it to the oceans. River engineering techniques, like levees that prevent flooding, change the way carbon is cycled through rivers, but it is difficult to identify and quantify these changes. Shen et al. (2021) were able to quantify changes in river organic carbon fluxes induced by bank stabilization in the Mississippi River. The authors compared the age distribution of organic carbon in modern river sediment and old river sediment deposited before the construction of extensive levee systems. They found that bank stabilization significantly reduces the amount of time organic carbon spends in the river system before being exported to the Gulf of Mexico. As a result, less organic carbon is oxidized to CO 2 and more organic carbon is exported to the ocean, ultimately reducing atmospheric CO 2 . This study highlights an important effect of anthropogenic activity on river carbon fluxes that should be considered in global carbon cycle models.