Unexpectedly minor nitrous oxide emissions from fluvial networks draining permafrost catchments of the East Qinghai-Tibet Plateau

Streams and rivers are significant sources of nitrous oxide (N2O), a potent greenhouse gas. Permafrost thaw releases large amounts of nitrogen, potentially increasing N2O emissions from these waterways. This study investigated N2O concentrations and fluxes in four East Qinghai-Tibet Plateau watersheds. Despite high N2O potential from thawing permafrost, these rivers were unexpectedly minor N2O sources due to low riverine dissolved inorganic nitrogen (DIN) after terrestrial plant uptake, unfavorable conditions for N2O generation via denitrification, and a low N2O yield. Fluvial N2O emissions from the entire Qinghai-Tibet Plateau are estimated to be marginal. However, future warming may shift these rivers from minor to strong emitters, intensifying warming via a permafrost non-carbon feedback.

Liwei Zhang, Sibo Zhang, Xinghui Xia, Tom J. Battin, Shaoda Liu, Qingrui Wang, Ran Liu, Zhifeng Yang, Jinren Ni, Emily H. Stanley