海洋地质与第四纪地质2026，Vol.46Issue(3)：1-11,11.DOI:10.16562/j.cnki.0256-1492.2025062901
北部湾海底表层沉积物有机碳丰度分布与碳氮同位素组成分析
Distribution of organic carbon abundance and carbon-nitrogen isotope composition of surface sediment in the Beibu Gulf
摘要
Abstract
As a semi-enclosed sea,the Beibu Gulf is an important site for the deposition and burial of organic carbon.The spatial distribution and sources of sedimentary organic carbon are of great significance for estimating regional sedimentary organic carbon sinks.Analyses on the contents and isotopic compositions of total organic carbon(TOC)and total nitrogen(TN)in 16 surface sediment samples taken from the northern Beibu Gulf revealed that the TOC content in the surface sediments ranged from 0.07 to 0.84 wt%,on average of 0.38 wt%,while the TN content ranges from 0.02 to 0.15 wt%,on average of 0.07 wt%.A significant positive linear correlation between TOC and TN indicates that nitrogen existed mainly as organic nitrogen bound to organic carbon.The distribution range of the organic carbon isotope composition was from-21.9 ‰ to-20.7 ‰,on average of-21.2 ‰,suggesting that the organic matter in the surface sediments was predominantly sourced from autochthonous marine inputs,although the mixed input of terrestrial and marine organic matter was also evident.Calculations showed that the proportion of terrestrial organic matter input ranged from 17.4%to 47.6%,on average of 29.0%.The nitrogen isotope composition ranged from 7.6‰ to 13.9‰,on average of 11.0‰;and the abnormally high δ15Nbulk values of sediments near the coastal zone and Weizhou Island might be related to anthropogenic nitrogen inputs.This study provided a scientific support for analyzing the intrinsic relationship between carbon and nitrogen distribution of sediments in the Beibu Gulf,for estimating sedimentary organic carbon sinks,and for regulating marine sedimentary organic carbon sinks.关键词
海底表层沉积物/TOC/TN/有机碳氮同位素/北部湾Key words
surface sediments/TOC/TN/organic carbon and nitrogen isotope/Beibu Gulf分类
海洋科学引用本文复制引用
姚立朋,陈娟,曹新星,农兰馨,宋之光..北部湾海底表层沉积物有机碳丰度分布与碳氮同位素组成分析[J].海洋地质与第四纪地质,2026,46(3):1-11,11.基金项目
广西科技基地和人才专项"北部湾海洋环境演变及其气候变化响应研究"(AD22035046),"北部湾海洋沉积界面不同含氮组分的氮同位素组成特征及分馏机理"(AD23026072) （AD22035046）
广西自然科学青年科学基金项目"亚热带陆缘海沉积物中不同赋存状态氮同位素组成特征及其地球化学意义"(2025GXNSFBA069505) （2025GXNSFBA069505）
国家自然科学基金项目"储层固体沥青形成演化过程微量元素配分机制及其烃源对比意义"(42302172) （42302172）
