渤、黄海表层沉积物有机碳的分布特征及影响因素研究  

Spatial distribution and influencing factors of organic carbon in surface sediments of the Bohai Sea and Yellow Sea

作　　者：翟晓辉 王华伟 夏天 高建华[3] 聂天亦 游子骏 宋秀青[4] 李芯芯 Zhai Xiaohui;Wang Huawei;Xia Tian;Gao Jianhua;Nie Tianyi;You Zijun;Song Xiuqing;Li Xinxin(Shenzhen Marine Development Research Promotion Center,Shenzhen 518052,China;Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China;School of Geography and Ocean Science,Nanjing University,Nanjing,210023,China;Shanghai Sheshan National Geophysical Observatory,Shanghai Earthquake Agency,Shanghai 201602,China)

机构地区：[1]深圳市海洋发展研究促进中心,广东深圳518052 [2]南方科技大学海洋科学与工程系,广东深圳518055 [3]南京大学地理与海洋科学学院,江苏南京210023 [4]上海市地震局上海佘山地球物理国家野外科学观测研究站,上海201602

出　　处：《海洋学报》2025年第1期13-24,共12页

基　　金：国家自然科学基金(42076029,42276045);深圳市海洋发展研究促进中心项目(SZDL2023000925);上海佘山地球物理国家野外科学观测研究站开放课题项目(SSKP202202)。

摘　　要：了解海洋沉积物有机碳的分布特征及其影响因素对深入探究全球碳循环机制并应对气候变化意义重大。本研究通过渤、黄海表层沉积物碳、氮、硫元素及其同位素(TOC、TN、TS、S^(2-)、δ^(13)C、δ^(15)N、δ^(34)S)测定,结合比表面积、色素生物标志物、热重分析等,阐明了沉积物有机碳的来源组成、分布特征及其主要约束机制。结果表明,受水动力条件控制,TOC和TN含量呈现近岸低、远岸高的分布特征,且受沉积物比表面积显著影响。同位素端元分析结果表明沉积物中混合了陆地植物、土壤和海洋藻类有机碳。其中黄河口及辽东半岛近岸海域土壤输入影响较大,有机碳碳反应指数较小;而南黄海海洋藻类影响较大,有机碳碳反应指数较高。渤海及北黄海沉积物TOC与TS的显著相关性表明有机碳降解与硫酸盐还原过程密切相关,较负的δ^(34)S表明沉积物-水界面的硫酸盐还原-硫化物氧化-海水硫酸盐扩散的循环过程,暗示了该区域有机质有氧到无氧的降解过程,其中色素降解潜在导致其与表层沉积物TOC之间相关性较弱。随着日益频发的藻华和水体缺氧效应,未来研究需进一步关注海水水体氧化还原条件与表层沉积物元素循环的耦合关系,这对理解大陆架沉积物有机碳埋藏具有重要意义。Understanding the distribution and relevant controlling factors of organic carbon in the ocean is of great significance to study the global carbon cycle and tackle climate change.Here,surface sediment samples were collected from the Bohai Sea and the Yellow Sea.For illustrating the source composition,distribution pattern,and their constraints,material characterization such as specific surface area,total organic carbon,nitrogen,sulfur contents and their isotopes(TOC,TN,TS,S^(2-),δ^(13)C,δ^(15)N,andδ^(34)S),as well as pigment biomarkers and thermos-gravimetric analysis were conducted.The results showed that the TOC and TN contents were lower in the nearshore but higher in the offshore region due to stronger hydrodynamics nearshore.The specific surface area had significant impacts on the distribution of organic carbon.The sediments contain a mixture of organic carbon from land plants,soil,and marine algae.Three-endmember mixing model suggested that sediments near the Huanghe River mouth and the shallower region along the Liaodong Peninsula in the Bohai Sea were dominated by soil-derived organic carbon with a smaller carbon reactivity index,while marine phytoplankton contributed mostly to the southern Yellow Sea with increasing carbon reactivity index.Significant correlation between TOC and TS in the Bohai Sea and northern Yellow Sea indicated significant linkages between organic carbon degradation and sulfate reduction.The negativeδ34S indicated the process of sulfate reduction-sulfide oxidation-seawater sulfate diffusion at the sedimentwater interface,which hinted the oxidation of organic carbon from oxic to anoxic condition.Pigment degradation potentially resulted in its weak correlation with the TOC content.As the risk of harmful algal bloom and hypoxia is becoming more severe,it is essential to monitor the coupling relationship of water chemistry and elemental cycling in the sediment to comprehensively understand the role of the continental shelf on organic carbon burial.

关 键 词：渤、黄海 表层沉积物 有机碳 硫同位素 色素 热重分析 

分 类 号：P593[天文地球—地球化学]