滇池的富营养化过程:来自结合态脂肪酸C 16:0 δ 13 C的证据
滇池的富营养化过程:来自结合态脂肪酸C 16:0 δ 13 C的证据
复制标题
DOI：
10.18307/2009.0402
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
王丽芳;熊永强;吴丰昌;房吉敦;李芸
中科院分区：
文献类型：
--
作者：
王丽芳;熊永强;吴丰昌;房吉敦;李芸
本文旨在研究云贵高原浅水湖泊滇池沉积环境的变化。分析了湖中心63 cm长柱状样有机质δ 13 Corg、δ 13 N、C/N和TOC的总体特征。结合脂肪酸的浓度和稳定碳同位素组成也进行了分析，并与相应的游离脂肪酸进行了比较。结果表明，滇池现代沉积物中记录的过去环境变化可分为三个主要阶段。δ 13 N和TOC值在0- 20 cm的最后阶段呈上升趋势，与滇池富营养化过程有关，此时结合脂肪酸和游离脂肪酸的浓度分别为38.5-209.6μg/g和12.0-318.1μg/g。与游离脂肪酸相比，滇池沉积物中的结合脂肪酸中不饱和脂肪酸、异支链脂肪酸和反异支链脂肪酸的含量更高，说明其主要来源于浮游生物和细菌，且更耐早期化学和生物降解。浮游生物和细菌的大量繁殖加速了湖泊富营养化进程。滇池沉积物中结合态nC 16：0脂肪酸δ 13 C值的变化较好地记录了近几十年来滇池富营养化程度的增强。因此，它将成为反映湖泊富营养化程度的重要指标。
The purpose of this study is to investigate changes in sedimentary environments in Lake Dianchi, a shallow water lake on the Yun-Gui Plateau. Overall characteristics of organic matter values, including δ13Corg, δ13N, C/N and TOC, from a 63cm-long core from the center of the lake were analyzed. Concentrations and stable carbon isotopic compositions of the bound fatty acids are also analyzed and compared with those of the corresponding free fatty acids. The results indicate that the past environment changes recorded in the modern sediments in Lake Dianchi can be divided into three main stages. Values of δ13N and TOC increased during the latest stage of the 0-20cm interval and were related with the eutrophication process of the Lake Dianchi, when concentrations ofbound fatty acids and free fatty acids range from 38.5-209.6μg/g and 12.0-318.1μg/g, respectively. Compared to free fatty acids, bound fatty acids in the sediments of Lake Dianchi have more abundant unsaturated fatty acids, iso- and anteiso-branched fatty acids, indicating that they predominantly sourced from the plankton and bacteria and were more resistant to the early chemical and biological degradation. Multiplying of the plankton and bacteria caused the speeding up the lake eutrophication processes. Changes in the δ13C value of the bound nC16:0 fatty acid were recorded well in Lake Dianchi sediments and provided good information of the enhancement of lake eutrophication in the recent few decades. Therefore, it will become an important indicator reflecting the lake hyper-eutrophication.