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

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

doi:10.1038/s41467-022-28651-8

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

Nat Commun. 2022 Feb 17;13(1):950. doi: 10.1038/s41467-022-28651-8.

Authors

Liwei Zhang^#^{1

2}, Sibo Zhang^#³, Xinghui Xia⁴, Tom J Battin⁵, Shaoda Liu¹, Qingrui Wang¹, Ran Liu⁶, Zhifeng Yang³, Jinren Ni⁷, Emily H Stanley⁸

Affiliations

¹ Key Laboratory of Water and Sediment Sciences of Ministry of Education & State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, China.
² Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China.
³ Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China.
⁴ Key Laboratory of Water and Sediment Sciences of Ministry of Education & State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, China. xiaxh@bnu.edu.cn.
⁵ Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
⁶ Department of Mathematics, Beijing Jiaotong University, Beijing, China.
⁷ Key Laboratory of Water and Sediment Sciences of Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, China.
⁸ Center for Limnology, University of Wisconsin-Madison, Madison, WI, USA.

^# Contributed equally.

Abstract

Streams and rivers emit substantial amounts of nitrous oxide (N₂O) and are therefore an essential component of global nitrogen (N) cycle. Permafrost soils store a large reservoir of dormant N that, upon thawing, can enter fluvial networks and partly degrade to N₂O, yet the role of waterborne release of N₂O in permafrost regions is unclear. Here we report N₂O concentrations and fluxes during different seasons between 2016 and 2018 in four watersheds on the East Qinghai-Tibet Plateau. Thawing permafrost soils are known to emit N₂O at a high rate, but permafrost rivers draining the East Qinghai-Tibet Plateau behave as unexpectedly minor sources of atmospheric N₂O. Such low N₂O fluxes are associated with low riverine dissolved inorganic N (DIN) after terrestrial plant uptake, unfavorable conditions for N₂O generation via denitrification, and low N₂O yield due to a small ratio of nitrite reductase: nitrous oxide reductase in these rivers. We estimate fluvial N₂O emissions of 0.432 - 0.463 Gg N₂O-N yr^-1 from permafrost landscapes on the entire Qinghai-Tibet Plateau, which is marginal (~0.15%) given their areal contribution to global streams and rivers (0.7%). However, we suggest that these permafrost-affected rivers can shift from minor sources to strong emitters in the warmer future, likely giving rise to the permafrost non-carbon feedback that intensifies warming.

Publication types

Research Support, Non-U.S. Gov't