辽河口浅海湿地表层沉积物中正构烷烃的组成、分布及来源  

Composition,distribution and origination of n-alkanes in surface sediments from shallow sea wetlands in the Liaohe River estuary

作　　者：丁喜桂[1,2,3,4] 叶思源 苏大鹏[1,2,3,4] 袁红明 王锦 郭志刚[5] DING Xigui;YE Siyuan;SU Dapeng;YUAN Hongming;WANG Jin;GUO Zhigang(Qingdao Institute of Marine Geology,China Geology Survey,Qingdao 266237,China;Northern Observation and Research Station of Coastal Salt Marshes,Ministry of Natural Resources(NORS,MNR),Qingdao 266237,China;Key Laboratory of Coastal Wetland Biogeosciences,China Geology Survey,Qingdao 266237,China;Laboratory for Marine Geology,Qingdao Marine Science and Technology Center,Qingdao 266237,China;Department of Environmental Science and Engineering,Fudan University,Shanghai 200433,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,青岛266237 [2]自然资源部北方滨海盐沼湿地生态地质野外科学观测研究站,青岛266237 [3]中国地质调查局滨海湿地生物地质重点实验室,青岛266237 [4]青岛海洋科技中心海洋地质过程与环境功能实验室,青岛266237 [5]复旦大学环境科学与工程系,上海200433

出　　处：《海洋地质与第四纪地质》2025年第1期18-28,共11页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金区域创新发展联合基金重点项目(U22A20558);崂山实验室科技创新项目(LSKJ202204400);中国地质调查局地质调查项目(DD20189503,DD20221775);山东省自然科学基金(ZR2023MD060);海洋负排放国际大科学计划(ONCE)。

摘　　要：基于辽河口浅海湿地采集的53个表层沉积物样品,测试其正构烷烃的组成及含量,系统分析了正构烷烃的组成、分布及其分子组合特征,对正构烷烃的来源进行了分析。结果显示,研究区表层沉积物中正构烷烃以双峰群分布为主,表明本区有机质受陆源和海源共同作用;前峰群偶碳数正构烷烃优势明显,以海洋浮游藻类和细菌来源为主;后峰群奇碳数正构烷烃占明显优势,以陆生高等植物来源为主,其中木本植物来源约占49%,草本植物来源约占39.6%;陆、海源烷烃含量之和的比值(ΣT/ΣM)对有机质来源的指示与陆、海源优势烷烃含量之和的比值(TAR)均指示本研究区域陆源有机质贡献大于海源有机质。特别是,高比值区均集中分布于辽河河口近岸区域,且显示自近岸向外呈降低的趋势,表明河口处陆源输入最强。对正构烷烃分子组成特征指数的深入剖析表明辽河口浅海湿地沉积有机质主要来源于陆源输入,定量估算结果显示陆生植物贡献比例最大,平均为66.41%±10.74%。研究结果表明,河口湿地生态系统对近岸海区的碳汇贡献巨大。Fifty-three surface sediment samples were collected in the shallow sea wetland of Liaohe River estuary,Liaodong Bay,Bohai Sea,NW China.The composition and content of the sediment-borne n-alkanes,the composition distribution,and molecular combination characteristics of the n-alkanes were systematically analyzed.Results show that the n-alkanes in the study area displayed bimodal distributions,indicating that they were influenced by a mixture of terrestrial and marine sources.The first peak reflected obviously short-chain alkanes,indicating organic origination from marine planktonic algae and bacteria;and the second peak suggested odd-carbon n-alkanes,indicating organic source from terrestrial higher plants,of which woody plants accounted for about 49%and herbaceous plants for about 39.6%.Both the ratio of the total hydrocarbon contents from terrestrial and marine sources and the ratio of the total contents of dominant alkanes from land and sea sources agreed with the organic origination of the n-alkanes.Except for a few stations where the two ratios were less than 1,all other areas had the two ratios greater than 1,indicating that land-sourced organic matter was greater than marine-sourced one in this study area.In particular,the high-ratio areas were concentrated in the coastal areas of the Liaohe River estuary,and showed a decreasing trend from the coast to the outside,indicating that the terrestrial input was the strongest in the estuary.In-depth analysis of the characteristic index of the molecular composition of n-alkane showed that the sedimentary organic matter in the shallow marine wetland of the Liaohe River estuary mainly came from terrestrial input.The quantitative estimation results show that terrestrial plants contributed the largest proportion,averaging 66.41%±10.74%.It can be seen that the estuarine wetland ecosystem contributes greatly to the carbon sink in the coastal sea area.

关 键 词：表层沉积物 正构烷烃 有机质 浅海湿地 辽河口 

分 类 号：P736[天文地球—海洋地质]