文献类型：期刊文献

英文题名：Nitrate sources and biogeochemical processes identified using nitrogen and oxygen isotopes on the eastern coast of Hainan Island

作者：Chen, Fajin[1,4];Lao, Qibin[1,3,4];Zhang, Shuwen[1,2,4];Bian, Peiwang[1,4];Jin, Guangzhe[1,4];Zhu, Qingmei[1,4];Chen, Chunqing[1,4]

机构：[1]Guangdong Ocean Univ, Coll Ocean & Meteorol, Zhanjiang 524088, Peoples R China;[2]Shantou Univ, Inst Marine Sci, Shantou 515031, Peoples R China;[3]State Ocean Adm, Marine Environm Monitoring Ctr Beihai, Beihai 536000, Peoples R China;[4]Guangdong Ocean Univ, Guangdong Prov Key Lab Coastal Ocean Variat & Dis, Zhanjiang 524088, Peoples R China

年份：2020

卷号：207

外文期刊名：CONTINENTAL SHELF RESEARCH

收录：SCI-EXPANDED(收录号：WOS:000571542900004)、、Scopus(收录号：2-s2.0-85090051393)、WOS

基金：We would like to thank professors Jie Xu and Zhen Shi for their support in collecting water samples. This work was supported by the National Key Research and Development Plan (2016YFC1401403), National Natural Science Foundation of China (U1901213, 40876005, and 41676008), Guangdong Natural Science Foundation of China (2016A030312004), International Science and Technology Cooperation Programme (GASI-IPOVAI-04), Scientific Research Start-Up Foundation of Shantou University (NTF20006), and Project of Enhancing School with Innovation of Guangdong Ocean University (GDOU2016050260).

语种：英文

外文关键词：Dual Nitrate isotopes; Hainan Island; Upwelling; Bayesian isotope mixing model

外文摘要：The multiple and complex N sources in coastal upwelling areas make it difficult to understand the behaviour of the N cycle. Stable N and O isotopes (delta N-15 and delta O-18) of nitrate (NO3-) from coastal upwelling off eastern Hainan Island in the South China Sea (SCS) identified the main NO3- sources and the processes that control NO(3)(- )distribution in the area. Our results revealed that upwelling occurred in the nearshore area of transects Q2 and Q3, and that the sources of NO3- in the surface water were mainly upwelling from the bottom water (50%), followed by nitrification (34%) and atmospheric deposition (AD) (16%). In the nearshore surface water of Transect Q1, the sources of NO3- were mostly manure and sewage (31%), followed by AD (24%), soil N (24%), and N in fertiliser (21%). Complete assimilation was an important process in the surface water. For the offshore area, NO3- assimilation and AD were the primary processes that affected N concentrations, and the proportion of AD was 30% in the upper water of the eastern coast of Hainan Island in the northern SCS. In the bottom water, coupled nitrification-denitrification could occur in sediment porewater and/or sediment-water interface, the isotope signal of which could then be diffused into the bottom water. The degree of denitrification for NO3- in the bottom water of the eastern Hainan coast ranged from 7.2% to 29.8% with an average of 22.5%. Our results suggested that upwelling plays an important role in the N cycle on the eastern coast of Hainan Island.