生物标志化合物对东、西太湖不同湖泊类型的判识

CLASSIFYING LAKE TYPES USING BIOLOGICAL MARKERS

从生物标志化合物的角度 ,对东、西太湖沉积物中饱和烃组分进行了分析 ,通过对其正构烷烃碳数分布型式、主峰碳位置、L/H等指标对比 ,对照西太湖中的主要水生植物蓝藻和东太湖中的主要水生植物的饱和烃的组成特征 ,同时结合常规指标C/N的分析结果 ,对东、西太湖湖泊类型进行判识———西太湖为藻型湖泊 ,东太湖为草型湖泊。

In the present study,alkane based organic markers are used to distinguish between different lake types.Further,the organic geochemical characteristics of the surficial sediments of Taihu Basin are described. Taihu Lake is one of the largest freshwater lakes in China. Its east basin supports a dense population of vascular plants (sediment C/N=13.8) while the west basin is almost free of vascular plants and supports a high phytoplankton (predominantly cyanobacteria) biomass (sediment C/N=7.95).In the eutrophic west basin,the mormal alkanes and fatty acids were primarily short chain molecules (major carbon peaks at C 15 and C 17 ),whilst the mesotrophic east basin sediments contained normal alkanes and fatty acids with longer chain molecules (major carbon peaks at C 24 to C 30 ).Thus,biological marker data provide paleolimnologists with another tool in distinguishing between mesotrophic vascular plant dominated lakes and eutrophic cyanobacteria dominated lakes.