Exogenous nitrogen input skews estimates of microbial nitrogen use efficiency by ecoenzymatic stoichiometry

作     者：Lifei Sun Daryl L.Moorhead Yongxing Cui Wolfgang Wanek Shuailin Li Chao Wang Lifei Sun;Daryl L.Moorhead;Yongxing Cui;Wolfgang Wanek;Shuailin Li;Chao Wang

作者机构：CAS Key Laboratory of Forest Ecology and ManagementInstitute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Environmental SciencesUniversity of ToledoToledo 43606USA Sino-French Institute for Earth System ScienceCollege of Urban and Environmental SciencesPeking UniversityBeijing 100871China Division of Terrestrial Ecosystem ResearchCenter of Microbiology and Environmental Systems ScienceUniversity of ViennaDjerassiplatz 11030 ViennaAustria 

出 版 物：《Ecological Processes》 (生态过程（英文）)

年 卷 期：2023年第12卷第1期

页      面：625-631页

核心收录：

学科分类：09[农学] 0901[农学-作物学] 

基　　金：funded by the National Key Research and Development Program of China(2020YFA0608100) the National Natural Science Foundation of China(32001174 and 32101378) the Major Program of Institute of Applied Ecology,Chinese Academy of Sciences(IAEMP202201) Key Research Program of Frontier Sciences,Chinese Academy of Sciences(ZDBS-LY-DQC019) Project funded by China Postdoctoral Science Foundation(2022M710004) 

主　　题：Extracellular enzyme Resource allocation Nitrogen addition Microbial metabolism limitation Isotope labeling 

摘      要：Background Ecoenzymatic stoichiometry models(EEST)are often used to evaluate microbial nutrient use efficiency,but the validity of these models under exogenous nitrogen(N)input has never been ***,we investigated the effects of long-term N addition(as urea)on microbial N use efficiency(NUE),compared EEST and^(18)O-labeling methods for determining NUE,and evaluated EEST’s theoretical assumption that the ratios of standard ecoenzymatic activities balance resource availability with microbial *** We found that NUE estimated by EEST ranged from 0.94 to *** contrast,estimates of NUE by the^(18)O-labeling method ranged from 0.07 to *** large differences in NUE values estimated by the two methods may be because the sum ofβ-N-acetylglucosaminidase and leucine aminopeptidase activities in the EEST model was not limited to microbial N acquisition under exogenous N inputs,resulting in an overestimation of microbial NUE by *** addition,the acquisition of carbon by N-acquiring enzymes also likely interferes with the evaluation of NUE by *** Our results demonstrate that caution must be exercised when using EEST to evaluate NUE under exogenous N inputs that may skew standard enzyme assays.