文献类型：期刊文献

英文题名：High nitrogen isotope fractionation of nitrate during denitrification in four forest soils and its implications for denitrification rate estimates

作者：Wang, Ang[1,2,6,7] Fang, Yunting[1,6] Chen, Dexiang[2] Phillips, Oliver[3] Koba, Keisuke[4] Zhu, Weixing[1,5] Zhu, Jiaojun[1,6]

第一作者：Wang, Ang

通信作者：Chen, DX[1];Fang, YT[2]

机构：[1]Chinese Acad Sci, Inst Appl Ecol, CAS Key Lab Forest Ecol & Management, Shenyang 110164, Liaoning, Peoples R China;[2]Chinese Acad Forestry, Res Inst Trop Forestry, Guangzhou 510520, Guangdong, Peoples R China;[3]Univ Leeds, Sch Geog, Leeds, W Yorkshire, England;[4]Kyoto Univ, Ctr Ecol Res, Otsu, Shiga 5202113, Japan;[5]SUNY Binghamton, Dept Biol Sci, Binghamton, NY 13902 USA;[6]Chinese Acad Sci, Qingyuan Forest CERN, Shenyang 110016, Liaoning, Peoples R China;[7]Univ Chinese Acad Sci, Coll Resources & Environm, Beijing 100049, Peoples R China

年份：2018

卷号：633

起止页码：1078-1088

外文期刊名：SCIENCE OF THE TOTAL ENVIRONMENT

收录：;EI(收录号：20181404974723);Scopus(收录号：2-s2.0-85044588363);WOS:【SCI-EXPANDED(收录号:WOS:000432475300104)】；

基金：This work was financially supported by the National Key Research and Development Program of China (grant number 2016YFA0600802); the Strategic Priority Research Program of Chinese Academy of Sciences (grant number XDB15020200); the National Natural Science Foundation of China (grant numbers 31370464, 31422009 and 41773094); the Key Research Program of Frontier Sciences of Chinese Academy of Sciences (grant number QYZDB-SSW-DQC002); the Hundred Talents Program of Chinese Academy of Sciences (grant number Y1SRC111J6) and the Key Laboratory of Tropical Forest Ecology of Chinese Academy of Sciences (grant number 09KF001B04). The work was also jointly supported by the Jianfengling National Key Field Station. We are grateful to Dr. Sarah A. Batterman for suggestions for the organization of the manuscript, the presentation of results and the novelty of the study as well as numerous edits of the language. Constructive comments by reviewers and the editor have greatly improved the quality of this paper. The authors declare no competing financial interests.

语种：英文

外文关键词：Denitrification; N-isotope fractionation; O-isotope fractionation; Delta delta O-18:Delta delta N-15; Forest soils; Gaseous N losses

摘要：Denitrification is a major process contributing to the removal of nitrogen (N) from ecosystems, but its rate is difficult to quantify. The natural abundance of isotopes can be used to identify the occurrence of denitrification and has recently been used to quantify denitrification rates at the ecosystem level. However, the technique requires an understanding of the isotopic enrichment factor associated with denitrification, which few studies have investigated in forest soils. Here, soils collected from two tropical and two temperate forests in China were incubated under anaerobic or aerobic laboratory conditions for two weeks to determine the N and oxygen (O) isotope enrichment factors during denitrification. We found that at room temperature (20 degrees C), NO3- was reduced at a rate of 0.17 to 0.35 mu g N g(-1) h(-1), accompanied by the isotope fractionation of N ((15)epsilon) and O ((18)epsilon) of 31 parts per thousand to 65 parts per thousand (48.3 +/- 2.0 parts per thousand on average) and 11 parts per thousand to 39 parts per thousand (18.9 +/- 1.7 parts per thousand on average), respectively. The N isotope effects were, unexpectedly, much higher than reported in the literature for heterotrophic denitrification (typically ranging from 5 parts per thousand to 30 parts per thousand) and in other environmental settings (e.g., groundwater, marine sediments and agricultural soils). In addition, the ratios of Delta delta O-18:Delta delta N-15 ranged from 0.28 to 0.60 (0.38 +/- 0.02 on average), which were lower than the canonical ratios of 0.5 to 1 for denitrification reported in other terrestrial and freshwater systems. We suggest that the isotope effects of denitrification for soils may vary greatly among regions and soil types and that gaseous N losses may have been overestimated for terrestrial ecosystems in previous studies in which lower fractionation factors were applied. (C) 2018 Elsevier B.V. All rights reserved.