Climate warming reduces soil gaseous nitrogen losses in a temperate forest
Abstract
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.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (23)
Kai Huang
Di Wu
Dongwei Liu
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Yihang Duan
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Peter Dörsch
Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences
Klaus Butterbach-Bahl
Pioneer Center Land-Center for Landscape Research in Sustainable Agricultural Futures, Agroecology, Aarhus University
Xiaoming Fang
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Yuqi Liu
Chao Wang
Haoming Yu
School of Chemistry
Lingrui Qu
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Jingwen Xu
Department of Applied Chemistry, School of Chemistry and Materials Science, Hefei National Research Center for Physical Sciences at the Microscale
Geshere Abdisa Gurmesa
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Ronghua Kang
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences
Shushi Peng
Erik A. Hobbie
Earth Systems Research Center, Morse Hall, University of New Hampshire
Xiaotang Ju
School of Tropical Agriculture and Forestry, Hainan University
Shuijin Hu
College of Agro-Grassland Science, Nanjing Agricultural University
Oliver L. Phillips
Per Gundersen
Department of Geosciences and Natural Resource Management, University of Copenhagen
Weixing Zhu
Department of Biological Sciences, Binghamton University, State University of New York
Peter M. Homyak
Department of Environmental Sciences, University of California
Yunting Fang
Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences