南汇东滩湿地不同植被生长区沉积有机质的地球化学特征和来源  

Geochemical characteristics and sources of sedimentary organic matters at different vegetation communities of Nanhui Dongtan coastal wetland,Shanghai

作　　者：邢亚茹 陈琳莹 陈多福[1] XING Yaru;CHEN Linying;CHEN Duofu(College of Oceanography and Ecological Science,Shanghai Ocean University,Shanghai 201306,China;Suzhou Industrial Park Loufeng School,Suzhou 215021,Jiangsu,China)

机构地区：[1]上海海洋大学海洋科学与生态环境学院,上海201306 [2]苏州工业园区娄葑学校,江苏苏州215021

出　　处：《地球化学》2024年第6期835-848,共14页Geochimica

基　　金：国家自然科学基金项目(42176069)资助。

摘　　要：滨海湿地海陆交互作用强烈,植被类型丰富,是地球上生产力最高的生态系统之一,其显著的固碳效应在全球碳循环中起重要作用。本研究通过对长江口上海南汇东滩滨海湿地5个站位柱状沉积物的总有机碳(TOC)、总氮(TN)、有机质C、N同位素(δ^(13)C_(org)、δ^(15)N_(org))等分析,揭示C_(3)植物和藻类是埋藏沉积有机质的主要来源。无植被生长的光滩站位沉积物TOC含量最低,平均0.18%,估算的C_(3)植物来源有机质约38.0%,藻类约62.0%。海三棱藨草站位沉积物TOC平均含量为0.38%,C_(3)植物来源有机质约54.7%,藻类约45.3%。互花米草站位沉积物TOC平均含量为0.83%,C_(3)植物来源有机质约44.1%,藻类约55.9%。海堤外芦苇站位沉积物TOC平均含量为5.32%,C_(3)植物来源有机质约77.5%,C_(4)植物约22.5%,存在少量藻类有机质来源。海堤内芦苇站位沉积物TOC平均含量为0.58%,C_(3)植物来源有机质约44.8%,藻类约55.2%。由此可见,南汇滨海湿地生长的不同植被对沉积物有机质来源和碳埋藏能力有重要影响。Coastal wetlands are considered to be one of the most productive ecosystems on Earth’s surface because of their strong interaction between land and ocean and rich vegetation types.The significant carbon sequestration effect of coastal wetlands plays an important role in the global carbon cycle.In this study,the total organic carbon(TOC),total nitrogen(TN),and organic carbon and nitrogen isotopes(δ^(13)C_(org),δ^(15)N_(org))of sediments from five sites with different types of vegetation in the Nanhui Dongtan coastal wetland in the Yangtze River estuary were analyzed.The organic matter in the sediments of the Dongtan coastal wetland was mainly derived from autochthonic C_(3) plants and algae.The average TOC content of sediments from the mudflat site with no vegetation was only 0.18%,with mixed sources of C_(3) plants(38.0%)and algae(62.0%).The average TOC content of the sediments from the Scirpus mariqueter site was 0.38%,with mixed sources of C_(3) plants(54.7%)and algae(45.3%).The TOC average content of sediments from the Spartina alterniflora site was 0.83%,with mixed sources of C_(3) plants(44.1%)and algae(55.9%).The sediments of the bulrush site outside the seawall were significantly higher,with an average TOC content of 5.32%.Mixed sources of organic matter from C_(3) and C_(4) plants were estimated at 77.5% and 22.5%,respectively.The sediments from the bulrush sites inside the seawall had an average TOC content of 0.58%,with mixed sources of C_(3) plants(44.8%)and algae(55.2%).Therefore,vegetation in the Nanhui Dongtan coastal wetland has important implications for controlling the sources and burial of sedimentary organic matter.

关 键 词：沉积有机质 有机质来源 植被 东滩滨海湿地 上海 

分 类 号：P593[天文地球—地球化学]