南极普里兹湾沉积生物标志物记录及浮游植物群落结构变化

本文利用浮游植物标志物（菜子甾醇、甲藻甾醇和长链烯酮）作为重建单种浮游植物（硅藻、甲藻和颗石藻）的指标，对普里兹湾浮游植物群落结构的变化进行研究。结果表明研究海域表层沉积物和III-12柱样沉积物中的生物标志物记录具有明显的空间和时间变化特征。用生物标志物重建的浮游植物总量（菜子甾醇+甲藻甾醇+长链烯酮）变化范围在391.0~1470.6ng/g之间，在过去的大约100年时间里海洋初级生产力呈上升趋势，但近10年略有下降，这种分布趋势与区域气候变化密切相关。普里兹湾及其邻近海域表层沉积物中浮游植物标志物的总含量变化范围为215.2~1249.3 ng/g，重建的浮游植物生产量呈现湾内高、湾外低（陆坡、深海区最低）的特征，并与2005年现场调查资料表层海水叶绿素a、有机碳和生物硅含量分布趋势相符，最大值均出现在普里兹湾中心区域，这意味着底部被埋藏的浮游植物标志物总含量和硅藻植物群落有很高的一致性，反映出海洋底部对上层海洋过程的一致响应。

USING BIOMARKERS IN SEDIMENTS AS INDICATORS TO REBUILD THE PHYTOPLANKTON COMMUNITY IN PRYDZ BAY,ANTARCTICA

In this study, biomarkers, including brassicasterol, dinosterol and alkenone, in sediments were used as indicators to rebuild the changes in the phytoplankton community in the upper water columns of Prydz Bay, Antarctica. Records of biomarkers in surface and core sediment samples showed obvious changes at spatial and temporal scales. The biomass of phytoplankton determined from biomarkers ranged from 391.0 to 1470.6ng/g. The ocean primary productivity has increased in Prydz Bay over the past 100 years and this increase was closely related to the changing climate in this area. The total content of biomarkers in surface sediments from Prydz Bay and its adjacent area ranged from 215.8 to 1294.3ng/g. The rebuilt biomass of phytoplankton in Prydz Bay was higher than that outside the bay, which agreed with the distributions of chlorophyll a (Chl a), organic carbon and biogenic silica measured in surface waters using in situ observations. This consistency supports the use of biomarkers in sediment to reflect biogeochemical processes in the upper seawater.