南海表层沉积物生物标志物的分布特征及古生产力重建意义  

Distribution of phytoplankton biomarkers in surface sediments from the South China Sea and its implication for paleoproductivity reconstruction

作　　者：赵美训[1,2] 赵晓晨[1,2] 陈建芳[3] 邢磊[1,2] SARNTHEIN M 陆红峰 

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]中国海洋大学海洋有机地球化学研究所,山东青岛266100 [3]国家海洋局第二海洋研究所,海洋生态系统和生物地球化学重点实验室,浙江杭州310012 [4]Geologisch-Palaeontologisches Institut,University of Kiel [5]广州海洋地质调查局,广东广州510760

出　　处：《热带海洋学报》2009年第3期45-53,共9页Journal of Tropical Oceanography

基　　金：国家重点基础研究发展计划项目(2007CB815904);国家海洋局海洋生态与海洋生物地球化学重点实验室开放基金(LMEB200801);国家自然基金项目(40676044;40706021)

摘　　要：作为一种新的地球化学指标方法,多参数生物标志物法已被广泛应用于重建浮游植物生产力。这个方法假设沉积物中生物标志物含量基本可以反映光合层浮游植物的生产力。但对于这个假设还缺乏现场的证据验证,尤其是西太平洋边缘海地区现场证据。本文对南海表层沉积物中的浮游植物生物标志物含量分布进行了研究。通过对南海77个站位的调查,发现硅藻、甲藻和颗石藻3种主要浮游植物生物标志物的总含量变化范围为55-1147ng.g-1,陆源生物标志物C27+C29+C31正构烷烃总含量变化范围为57-732ng.g-1。浮游植物生物标志物高值主要分布在近岸区、越南外部及巽他陆架北部的2个上升流区等高生产力区。研究表明,生物标志物的含量分布与现代海洋调查和其他古生产力指标对比显示生物标志物法基本可以用来重建生产力。相对于总有机碳含量(To-tal organic carbon,TOC)和蛋白石,生物标志物指标可以更准确地重建南海生产力。同时我们也发现,由于氧化降解和陆源冲淡效应的影响,在南海北部陆坡区和吕宋西北上升流区表层沉积物中生物标志物的含量与表层生产力的变化出现偏差,因此,在南海利用沉积物中生物标志物含量重建生产力存在区域性限制。Multi-biomarkers have been widely used to reconstruct phytoplankton productivity based on the assumption that sedimentary biomarker contents reflect phytoplankton productivity in the photic zone. However, this assumption has not been thoroughly tested using water column or sedimentary data. Here the authors test this assumption using phytoplankton biomarker contents in surface sediments from the South China Sea. The total contents of the three biomarkers for diatoms, dinoflagellates and coccolithophorids in 77 sediment samples reveal a range of 55 to 1147 ng · g-1, while the terrestrial biomarker （C27 ＋C29 ＋C31 alkanes） contents range from 57 to 732 ng ·g-1. Higher values of the phytoplankton biomarkers occur in shallower environments and in the upwelling regions off Vietnam and north of the Sunda Shelf. This spatial pattern is similar to that revealed by modern surveys of water column phytoplankton abundance, providing evidence to support the use of biomarkers for paleoproductivity reconstruction. Compared with TOC （Total organic carbon） and opal, the biomarkers are better as a paleoproductivity proxy in the South China Sea. However, compared with modern survey results, the biomarker data reveal differences in the continental slope region of northern South China Sea and the upwelling region northwest of the Luzon, reflecting the effects of water column oxidation and terrestrial dilution on sedimentary biomarker contents. Therefore, there are regional limitations in the application of sedimentary biomarker contents for paleoproductivity reconstruction in the South China Sea.

关 键 词：生物标志物 南海 表层沉积物 生产力 

分 类 号：P736.2[天文地球—海洋地质]