Climate warming reduces soil gaseous nitrogen losses in a temperate forest

作者：Kai Huang, Di Wu, Dongwei Liu, Yihang Duan, Peter Dörsch, Klaus Butterbach‐Bahl, Xiao-Ming Fang, Yuqi Liu, Chao Wang, Haoming Yu, Lingrui Qu, Junjie Xu, Geshere Abdisa Gurmesa, Ronghua Kang, Shushi Peng, Erik A. Hobbie, Xiaotang Ju, Shuijin Hu, Oliver L. Phillips, Per Gundersen, Weixing Zhu, Peter M. Homyak, Yunting Fang · 发表于：Proceedings of the National Academy of Sciences · 年份：2025 · DOI：10.1073/pnas.2513401122 · 被引用次数：6 · 研究领域：Soil Carbon and Nitrogen Dynamics、Plant Water Relations and Carbon Dynamics、Peatlands and Wetlands Ecology

Global warming is projected to accelerate ecosystem nitrogen (N) loss via gaseous pathways, thereby decreasing N availability, a critical nutrient for primary productivity and carbon sequestration. However, the models forecasting this ecosystem N loss are based on laboratory experiments that are inherently uncertain and have had few in situ validations. Over 6 y, we measured ~200,000 soil nitric oxide (NO; an air pollutant) and nitrous oxide (N 2 O; a powerful greenhouse gas) fluxes and used an upscaling approach to estimate N 2 fluxes after warming a temperate forest by 2 °C. Against thermodynamic theoretical predictions, warming unequivocally lowered emissions of NO by 19% and of N 2 O by 16%. These lower gaseous N losses were not explained by complete reduction of NO and N 2 O to N 2 , leaching, nor plant uptake, but rather by the warming-induced drying of soils that constrained microbial activity, consistent with other warming experiments where precipitation was less than 1,000 mm y −1 . Our findings challenge ecosystem model assumptions where warming, alone, accelerates N emissions and underscores how warming-induced losses in soil moisture and shortened freeze-thaw periods can offset temperature effects. Our data underscore the need for explicit consideration of in situ soil moisture when predicting changes on the terrestrial N cycle as the planet warms.