湛江湖光岩玛珥湖沿岸植物正构烷烃分布特征及其H同位素组成  

n-Alkane distribution and hydrogen isotope in lakeside plants from Huguangyan Maar Lake in Zhanjiang,Southern China

作　　者：陈静怡 罗涛 詹兆文 王遥平 宋之光[2] CHEN Jingyi;LUO Tao;ZHAN Zhaowen;WANG Yaoping;SONG Zhiguang(College of Chemistry and Environment,Guangdong Ocean University,Zhanjiang 524088,Guangdong,China;Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Guangdong Laboratory of Marine Science and Engineering,South China(Zhanjiang),Zhanjiang 524013,Guangdong,China;Shenzhen Research Institute of Guangdong Ocean University,Shenzhen 518120,Guangdong,China)

机构地区：[1]广东海洋大学化学与环境学院,广东湛江524088 [2]中国科学院广州地球化学研究所,广东广州510640 [3]南方海洋科学与工程广东省实验室(湛江),广东湛江524013 [4]广东海洋大学深圳研究院,广东深圳518120

出　　处：《地球化学》2024年第2期246-256,共11页Geochimica

基　　金：国家自然科学基金项目(41602139);广东海洋大学“创新强校”资助项目(Q18301);广东海洋大学“冲一流”项目(231419029);广东海洋大学博士科研启动项目(R20030、R17001);广东海洋大学大学生创新训练项目(CXXL2022187);广东海洋大学本科创新团队项目(CXTD2023019);中国科学院广州地球化学研究所“科创计划”项目联合资助。

摘　　要：从湛江湖光岩玛珥湖沿岸随机采集主要的草本和木本植物,分析其叶蜡正构烷烃分布特征及单体H同位素(δ^(2)H)。结果表明,湖光岩玛珥湖沿岸植物叶蜡正构烷烃主要由长链烷烃(n-C29~n-C31)组成,具有明显的奇偶优势;平均碳链长度(ACL值)与碳优势指数(CPI值)呈负相关关系;不同种类植物之间的正构烷烃δ^(2)H值差异明显,木本植物正构烷烃的δ^(2)H值(-247‰~-107‰)比草本植物(-222‰~-94‰)低,可能与它们的内在特性和所利用的土壤水深度有关。通过对比不同生境下低、中、高纬度地区湖泊沿岸植物叶蜡正构烷烃δ^(2)H值发现,低纬度热带、亚热带地区的植物叶蜡正构烷烃具有更长的链长和更高的δ^(2)H值,但植物与降水之间的δ^(2)H分馏值随纬度变化相对恒定(约-120‰),说明湖泊生境沉积叶蜡正构烷烃单体δ^(2)H值是具有较大潜力的古水文代用指标。Samples of herbaceous and woody plants growing along the lakeside of the Huguangyan Maar Lake in Zhanjiang were collected at random and analyzed for leaf wax n-alkanes and compound-specific hydrogen isotope compositions.This study found a negative correlation between the average carbon chain length(ACL)and the carbon predominance index(CPI).Furthermore,it was observed that the hydrogen isotope compositions of n-alkanes varied significantly among different plant species,with woody plants exhibiting lowerδ^(2)H values(-247‰to-107‰)than herbaceous plants(-222‰to-94‰).This difference inδ^(2)H values may be attributed to the intrinsic characteristics of the plant types and the depth of soil water utilized.When comparing theδ^(2)H values of n-alkanes in the leaf waxes of plants along the lakeside in low-,mid-,and high-latitude regions,it was found that the n-alkanes in plants from tropical and subtropical regions have longer chain lengths and heavier hydrogen isotope compositions.However,theδ^(2)H fractionation between plant samples and precipitation remain relatively constant with latitude(approximately-120‰),indicating that the hydrogen isotope composition of n-alkane monomers in sedimentary leaf waxes from lake environments has great potential as a paleohydrological proxy.

关 键 词：玛珥湖 陆生植物 正构烷烃 H同位素 

分 类 号：P593[天文地球—地球化学]