台风“莫拉克”(2009)对浙闽沿岸泥质中心沉积有机质组成与分布的影响  

Impact of Typhoon Morakot(2009)on the compositions and distributions of sedimentary organic matter in the Mud Depo-center of Zhejiang-Fujian Coast

作　　者：李云海 林云鹏 王亮 龙邹霞 郑斌鑫 LI Yunhai;LIN Yunpeng;WANG Liang;LONG Zouxia;ZHENG Binxin(Third Institute of Oceanography,Ministry of Natural Resources,Xiamen 361005,China;Fujian Provincial Key Laboratory of Marine Physical and Geological Processes,Xiamen 361005,China;Academy of Advanced Carbon Conversion Technology,Huaqiao University,Xiamen 361021,China)

机构地区：[1]自然资源部第三海洋研究所,厦门361005 [2]福建省海洋物理与地质过程重点实验室,厦门361005 [3]华侨大学先进碳转化技术研究院,厦门361021

出　　处：《海洋地质与第四纪地质》2024年第5期27-37,共11页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金面上项目“厦门湾海洋微塑料污染演变及其物源耦合”(42176220);“台风对泉州湾入海污染物“从源到汇”过程的影响研究”(41976050)。

摘　　要：台风是天气尺度上对海洋环境影响最大的海气相互作用过程之一,在短时间内会对影响海域的海洋环境(包括沉积有机质等)产生巨大的影响。本文基于夏季台风前、后采集的浙闽沿岸泥质中心沉积物的粒度、总有机碳(TOC)、总氮(TN)以及碳同位素组成(δ^(13)C)的测试结果,分析了台风“莫拉克”(2009)对研究区沉积有机质来源及分布的影响,对比了台风“莫拉克”与其他不同路径的台风对沉积有机质分布影响的差异,探讨了影响差异的机制。结果显示,台风“莫拉克”(2009)对浙闽沿岸泥质区沉积物中TOC的来源和分布产生了显著影响。端元分析结果表明,浙闽沿岸泥质中心沉积物中有机碳主要来源于长江三角洲沉积物以及海洋自生有机质,在台风的影响下,浙闽沿岸泥质中心的初级生产力升高,进而增加了沉积物中海源有机碳的比例。同时,在台风的动力作用下,近岸沉积物发生了明显的侵蚀与再搬运,导致近岸沉积物中TOC的含量显著降低。受控于台风不对称风场造成的沉积动力差异,不同路径的台风会对研究区的物源输入、海洋生物地球化学以及沉积物的搬运改造等产生不同的影响,进而影响到沉积有机质的组成和分布。研究结果为全面认识极端海况影响下近岸陆架“碳埋藏”提供了科学依据。Typhoons are one of the most significant ocean-atmosphere interaction processes at the weather scale,exerting a large impact on the marine environment(including the deposition of organic matter)within a short period.The effects of Typhoon Morakot(2009)on the compositions and distributions of sedimentary organic matter(SOM)were analyzed.The distinct influence of typhoons following different paths on SOM was compared,and their mechanisms were discussed based on the analysis on grain size,total organic carbon(TOC),total nitrogen(TN),and carbon isotope composition(δ^(13)C)of sediments collected in the Mud Depo-center of the Zhejiang-Fujian Coast before and after Typhoon Morakot(2009).Results indicate that Typhoon Morakot(2009)significantly affected the compositions and distributions of TOC in the study area.The findings from a three end-member mixing model revealed that the sedimentary organic carbon in the study area originated primarily from the sediments of the Yangtze River Delta and marine phytoplankton.The influence of Typhoon Morakot led to an increase in primary productivity in the study area,resulting in a higher proportion of marine-sourced organic carbon in the sediments.Additionally,nearshore sediments experienced significant erosion and re-transport due to the dynamic effects of Typhoon Morakot,leading to a reduction in TOC content in the sediment.The differential response of sediment dynamics caused by the asymmetric wind field of typhoons with varying paths led to distinct impacts on material sources,marine biogeochemical processes,and sediment transport and modification processes within the same study area and thus had different impacts on the compositions and distributions of SOM.These findings provide a scientific basis for the comprehensive understanding of carbon burial in the coast and shelf under the influence of extreme marine dynamics.

关 键 词：台风"莫拉克" 沉积有机质 端元混合 沉积物再搬运 浙闽沿岸泥质沉积中心 

分 类 号：P736[天文地球—海洋地质]