Retention of deposited ammonium and nitrate and its impact on the global forest carbon sink

作者：Geshere Abdisa Gurmesa, Ang Wang, Shanlong Li, Shushi Peng, W. de Vries, Per Gundersen, Philippe Ciais, Oliver L. Phillips, Erik A. Hobbie, Weixing Zhu, Knute J. Nadelhoffer, Yi Xi, Edith Bai, Tao Sun, Dexiang Chen, Wenjun Zhou, Yiping Zhang, Yingrong Guo, Jiaojun Zhu, Lei Duan, Dejun Li, Keisuke Koba, Enzai Du, Guoyi Zhou, Xingguo Han, Shijie Han, Yunting Fang · 发表于：Nature Communications · 年份：2022 · DOI：10.1038/s41467-022-28345-1 · 被引用次数：144 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Peatlands and Wetlands Ecology

Abstract The impacts of enhanced nitrogen (N) deposition on the global forest carbon (C) sink and other ecosystem services may depend on whether N is deposited in reduced (mainly as ammonium) or oxidized forms (mainly as nitrate) and the subsequent fate of each. However, the fates of the two key reactive N forms and their contributions to forest C sinks are unclear. Here, we analyze results from 13 ecosystem-scale paired 15 N-labelling experiments in temperate, subtropical, and tropical forests. Results show that total ecosystem N retention is similar for ammonium and nitrate, but plants take up more labelled nitrate ( $${20}_{15}^{25}$$ 20 15 25 %) ( $${{{{{{\rm{mean}}}}}}}_{{{{{{\rm{minimum}}}}}}}^{{{{{{\rm{maximum}}}}}}}$$ mean minimum maximum ) than ammonium ( $${12}_{8}^{16}$$ 12 8 16 %) while soils retain more ammonium ( $${57}_{49}^{65}$$ 57 49 65 %) than nitrate ( $${46}_{32}^{59}$$ 46 32 59 %). We estimate that the N deposition-induced C sink in forests in the 2010s is $${0.72}_{0.49}^{0.96}$$ 0.72 0.49 0.96 Pg C yr −1 , higher than previous estimates because of a larger role for oxidized N and greater rates of global N deposition.