基于CiteSpace的岩溶地下水硝酸盐示踪研究进展OA北大核心CSTPCD

Nitrate(NO3-)is one of the main pollutants in groundwater;therefore,once NO3-concentrations exceed an acceptable level,it will have adverse effects on water ecology and human health.Identifying the sources and biogeochemical transformation process of nitrate in groundwater is of important theoretical and practical significance for pollution prevention and control.The karst groundwater system is characterized by high vulnerability.At present,studies on nitrate in karst groundwater based on nitrogen and oxygen isotope technology have made great progress but most of them were presented by case study,lacking a systematic summary of research progress.CiteSpace,the software of knowledge network analysis,uses bibliometrics and visualization methods,co-citation network,association rules,cluster analysis to analyze the research hotspots in a field in Chinese and foreign literature.CiteSpace enables readers to better understand the knowledge framework,research topics and future hot topics,and plays a very good role in promoting the analysis of research progress in different professional fields. To investigate the research progress of isotope tracing of nitrate sources in karst groundwater in recent years(from 2003 to 2022),and comprehensively analyze the research hotspots of nitrate in karst groundwater,"karst groundwater","karst aquifer","nitrate","nitrate-nitrogen","nitrogen isotope","oxygen isotope","MixSIAR","nitrate sources","nitrogen transformations","nitrate pollution",and"dual nitrate isotopes"were selected as subject terms in CNKI,and 1,191 papers were retrieved after the unrelated subject terms had been excluded.Meanwhile,subject terms of"karst groundwater","karst aquifer","nitrate","NOx-N","nitrogen isotope","oxygen isotope""MixSIAR","nitrate source","nitrogen transformation","nitrate contamination",and"dual nitrate isotopes"were searched in Web of Science(WOS)core collection database,and a total of 2,232 papers were retrieved.CiteSpace was employed to analyze publishing institutions,authors,keywords and research hotspots,and co-citations of both the retrieved Chinese literature and English literature. The results show that the Institute of Karst Geology of the Chinese Academy of Geological Sciences had a great advantage in studies of nitrate in karst water system,because this institute has published the largest number of academic papers written in Chinese.The keyword clustering of"#1 karst groundwater","#2 karst water","#5 karst water resources","#6 karst hydrological model"and"#11 karst aquifer"can be summarized as a research hotspot of karst hydrology and water resources.The keyword clustering of"#7 hydrogeochemistry","#8 hydrochemistry"and"#10 hydrochemical characteristics"can be summarized as a research hotspot of karst hydrochemistry and water environment.The keyword clustering of"#0 nitrate pollution","#3 karst","#4 groundwater","#9 stable isotope","#12 nitrogen and oxygen isotope"and"#13 source analysis"can be summarized as a research hotspot of nitrate pollution tracing in karst groundwater.In terms of English literature,the United States,China and Germany had the largest number of publications,and there was a relatively close cooperative relationship between them.Academic papers published by the Chinese Academy of Sciences ranked top among the researching institutes.The keyword clustering of"#0 karst","#5 macrophytes","#6 ecohydrology","#11 karst hydrology"and"#3 groundwater recharge"can be summarized as a research hotspot of karst ecology and hydrology research.The keyword clustering of"#10 groundwater","#2 nitrogen cycle","#9 nitrogen"and"#8 karst water"can be summarized as a research hotspot of nitrate transformation in karst groundwater(nitrogen cycle).The keyword clustering of"#1 source appointment","#12 nitrate pollution","#4 delta n15","#7 stable isotope"and"#13 nitrogen isotope"can be summarized as a research hotspot of nitrate pollution tracing in karst groundwater.The technology of dual nitrate isotopes provides a strong technical support for the research of nitrate tracing and biogeochemistry in karst groundwater.Isotopic fractionation effect should be considered to improve the accuracy of nitrate pollution tracing results.This paper aims to provide reference for the source tracing and effective prevention of nitrate pollution in karst groundwater in the future.