中文摘要：

通过多参数生物标志物法对取自中国第二次北极考察的R12a岩心顶部40 cm样品进行了浮游植物和种群结构变化的研究,获得了500 a以来浮游植物初级生产力和种群结构变化信息。结果表明：R12a岩心在过去的500多年来,所记录的海洋初级生产力呈上升趋势,单一藻类的生产力总体上也呈现上升趋势。浮游植物种群结构主要表现为颗石藻相对含量下降,硅藻相对含量上升,甲藻没有明显的波动,这可能与北太平洋水输入决定的楚科奇海营养盐结构及夏季海冰覆盖变化有关。

英文摘要：

This paper used multi-biomarkers to study the R12a core＇s top 40 cm samples＇phytoplankton and community sampled during the Second Chinese Arctic expedition from the Chukchi Sea in summer,2003,and to abtain the information of the phytoplankton production and community change since 500 a.The results indicate the total and individual primary productivity increased over the last 500 a.The phytoplankton community structure mostly show the contributions of coccolithforids decreased,the contribution of diatoms increased,and the relative abundances of dinoflagellates not have obvious changes.This may be related with the Chukchi Sea＇s nutrients structure which is determined by the waters from the north Pacific Ocean and the summer ice cover change in the Chukchi Sea.