文献类型：期刊文献

英文题名：Dual isotopic evidence for nitrate sources and active biological transformation in the Northern South China Sea in summer

作者：Chen, Fajin[1,2];Zhou, Xin[1,2];Lao, Qibin[1,2,3];Wang, Shuangling[1,2];Jin, Guangzhe[1,2];Chen, Chunqing[1,2];Zhu, Qingmei[1,2]

机构：[1]Guangdong Ocean Univ, Guangdong Prov Key Lab Coastal Ocean Variat & Dis, Zhanjiang, Peoples R China;[2]Guangdong Ocean Univ, Coll Ocean & Meteorol, Zhanjiang, Peoples R China;[3]State Ocean Adm, Marine Environm Monitoring Ctr Beihai, Beihai, Peoples R China

年份：2019

卷号：14

期号：1

外文期刊名：PLOS ONE

收录：SCI-EXPANDED(收录号：WOS:000454683200054)、、Scopus(收录号：2-s2.0-85059496762)、WOS

基金：This work was supported by the National Natural Science Foundation of China (41476066, 41466010, 41676008), Guangdong Natural Science Foundation of China (2016A030312004), International Science and Technology Cooperation Project (GASI-IPOVAI-04), National Key Research and Development Plan (2016YFC1401403), the Project of Enhancing School with Innovation of Guangdong Ocean University (GDOU2014050201, GDOU2013050215, GDOU2013050315, GDOU2013050201), and the Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry, SOA, (GCMAC1503) to FC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

语种：英文

外文摘要：Nitrate (NO3-) concentrations and their dual isotopic compositions (delta N-15-NO3- and delta O-18-NO3- ) were measured to constrain N sources and their cyclic processes in summer using samples from the water column of the northern South China Sea (NSCS). Our data revealed that higher NO3- concentrations and delta N-15-NO3- values were observed in the upper waters of the coastal areas near the Pearl River Estuary (PRE). The Bayesian stable isotope mixing model was used to calculated the proportion of nitrate sources, the results indicated that the nitrate in the upper waters of the coastal areas near PRE were mainly influenced by manure and sewage (63%), atmospheric deposition (19%), soil organic nitrogen (12%) and reduced N fertilizer (6%). For the upper waters of the outer areas, low NO3- concentrations and delta N-15-NO3- values, but high delta O-18-NO3- values, reflected that NO3- was mainly influenced by Kuroshio water intrusion (60%), atmospheric deposition (32%) and nitrogen fixation/nitrification (8%). Complex processes were found in bottom waters. Nitrification and phytoplankton assimilation may be responsible for the higher nitrate concentrations and delta N-15-NO3- values. Our study, therefore, utilizes the nitrate dual isotope to help illustrate the spatial variations in nitrate sources and complex nitrogen cycles in the NSCS.