长江口水淘选分级颗粒物中有机碳的来源、分布与降解  

Sources,Distribution,and Decay of Size-Fractionated Particulate Organic Carbon in the Changjiang Estuary Based on Water Elutriation

作　　者：潘慧慧[1,2] 姚鹏[1,3,4] 王金鹏[1,2] 张婷婷[1,2] 赵彬[1,2] 李栋[1,2] 

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,山东青岛266100 [2]中国海洋大学化学化工学院,山东青岛266100 [3]海洋科学与技术青岛协同创新中心,山东青岛266100 [4]中国海洋大学海洋有机地球化学研究所,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2016年第2期90-99,共10页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41176063;41221004)资助~~

摘　　要：对河流颗粒有机碳的来源和归宿的认识是全球碳循环研究的重要方面,而从分级的角度研究颗粒有机碳的输运过程,有助于深入了解其迁移转化过程。于2012年3月采集了长江口的表层悬浮颗粒物,采用水淘选法对其进行了分级分离,分析了这些颗粒物的有机碳含量、稳定碳同位素丰度及木质素等参数,结合颗粒物的质量百分组成,讨论了不同粒级颗粒物有机碳的分布、来源及降解情况。从质量分布上来说,长江口悬浮颗粒物的主要组成部分是〈32μm粒级的颗粒物。随粒径增大,颗粒有机碳的含量逐渐降低,但并不是最小粒级赋存最多的有机碳,大部分站位颗粒有机碳集中在16~32μm粒级颗粒物上（55%以上）。粗颗粒物（〉63μm）中有机碳含量低,N/C比较小,13 C较亏损,木质素含量较高,说明粗颗粒物中陆源有机碳的贡献较大,而在细颗粒物,尤其是〈8μm和8~16μm颗粒物中,除δ13 C外,其它参数的变化均与粗颗粒物的相反,其13 C则比粗颗粒物还要亏损,说明在这些粒级中,除了陆地高等植物外,土壤有机碳或淡水浮游植物的贡献可能也很重要。长江口不同粒级悬浮颗粒物的C/V值和S/V值均较小,表明颗粒物中木质素是被子植物组织与裸子植物组织的混合来源。随粒径增大,木质素降解参数,如（Ad/Al）v、P/（S＋V）和3,5-Bd/V均逐渐降低,表明细颗粒物中木质素的降解程度最高。Rivers,especially those large rivers,play a vital role in delivering a huge flux of organic carbon（OC）from the continents to the oceans.Large-river delta-front estuaries（LDEs）are therefore major landocean interfaces and play an important role in biogeochemical cycling of OC.Knowledge of the sources and fate of riverine particulate OC（POC）in LDEs is very essential to the research of global carbon cycling,and studying the transport of POC from the perspective of size fractionation is helpful to better understand the transformation of OC.In this study,surface suspended particulate matters（SPM）were collectedfrom the ChangjiangLDE in March 2012,and were separated into different size fractions using the water elutriation method.POC contents,stable carbon isotope abundance（δ13 C）,and lignin composition,as well as the mass distribution of these size-fractionated particles were determined in order to study the sources,distribution and decay of OC in the Changjiang Estuary.According to the mass distribution results,the major composition of SPM is the〈32μm fraction.POC contentsgradually decreased with the increase of particulate size,however,most of the OC was associated with the 16~32μm fraction（more than 55%）instead of the finest fraction.Coarse particles（〉63μm）had lower OC contents,smaller N/C ratios,depleted 13 C and higher lignin contents,indicating relatively high contribution of terrestrial OC,whereas the finegrainedparticles,especially the〈8μm and 8~16μmfractions had the very opposite OC parameters except theδ13C values,which were more negative than those in the coarse particles,indicated that the contribution of soil OCand/or freshwater phytoplankton to these fractions may also be important.Both the C/V（ratios of cinnamyl to vanillyl phenols）and S/V（ratios of syringyltovanillyl phenols）ratios of lignin phenols in different size-fractionated particles were small,indicated that the lignin tissues in SPM of the Changjiang Estuary is a mixture of angiosperms and gymnospe

关 键 词：长江口 悬浮颗粒物 水淘选分级 有机碳 稳定碳同位素 木质素 

分 类 号：P734.45[天文地球—海洋化学]