青海湖及柴达木盆地地区现代湖泊沉积物中长链烯酮的分布特征  

The distribution of long-chain alkenones in modern lacustrine sediments in the Lake Qinghai and lakes from the Qaidam Basin

作　　者：付明义[1] 刘卫国[1] 李祥忠[1] 徐黎明[2] 王政[1] 安芷生[1] 

机构地区：[1]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室 [2]中国科学院盐湖研究所,西宁810009

出　　处：《湖泊科学》2008年第3期285-290,共6页Journal of Lake Sciences

基　　金：国家自然科学基金项目(40599422,40523002,40121303);国家重点基础研究发展规划项目(2004CB720200)联合资助.

摘　　要：研究了我国青海湖和柴达木盆地地区不同类型湖泊表层沉积物中的长链烯酮.结果表明该地区湖泊中可能广泛存在长链烯酮.多数淡水湖、咸水湖现代沉积物中C37/C38>1,而盐湖中C37/C38<1.根据文献中报道的湖泊环境下长链烯酮不饱和度37UK′与温度的方程,估计的温度在青海湖地区处于实际温度范围内,而在柴达木盆地低于实际温度.结果亦显示在青海湖和柴达木盆地地区,长链烯酮的含量在咸水湖中要明显的高于淡水湖和盐湖,最高含量出现在咸水湖(盐度为103.2g/L)尕海中,高达86.09μg/g;这种含量和分布特征可能表明生产长链烯酮的藻类应该更喜欢生长于具有一定盐度的环境;长链烯酮含量的变化可能指示咸水或淡水环境.This paper analysed the existence of long-chain alkenones from the surface sediments in the Lake Qinghai and lakes in Qaidam Basin. The ratios of C37 to C38 alkenone is observed larger than 1 in both freshwater and saline lakes, while less than 1 in salt lakes. The calculated temperatures based on U^K＋37 equation reported in literatures can fall within the observed temperature ranges for the Lake Qinghai, but are lower than air temperatures observed for lakes in the Qaidam Basin. The abundances of the long-chain alkenones in the saline lakes are found higher than those in freshwater and salt lakes, with the highest abundance of 86.09g/L in Lake Gahal with salinity of 103.2g/L Such characteristics suggest that the algal precursors might prefer to live in water bodies with intermediate salinity but do not grow well either in freshwater or salt lakes. Thus the fluctuation of long-chain alkenone abundance might indicate variations of freshwater or saline environments.

关 键 词：长链烯酮 青海湖 柴达木盆地 盐度 丰度 

分 类 号：P592[天文地球—地球化学]