楚科奇海附近表层沉积物中类脂生物标志物的分布特征和意义

The distribution of lipids biomarkers in the surface sediments of the Chukchi Sea and their implications

多参数生物标记物法已被广泛用于重建浮游植物生产力和种群结构，研究了2003年夏季我国二次北极考察时采集的楚科奇海表层沉积物样品中浮游植物生物标志物的比例变化及其作为浮游植物种群结构替代指标的潜力。观测海区表层沉积物中菜子甾醇、甲藻甾醇、长链烯酮的总含量为20～3149ng／g，平均值为1010ng／g，生物标志物总量分布表明南部的楚科奇陆架海域生产力明显高于北部海台区，不同站位的菜子甾醇和甲藻甾醇相对比例有明显变化，但都显示菜子甾醇占优势，楚科奇海陆架的站位中都是硅藻为主，菜子甾醇占生物标志物总量的比例为42％～74％，甲藻甾醇占生物标志物总量的比例为17％～37％，在海台区仍然是硅藻占优势，但是甲藻和颗石藻的比例有了很大的提高，加拿大海盆的4个站位中以甲藻和颗石藻为主，硅藻并非加拿大海盆的优势种群。这与用显微镜下鉴定得到的硅藻和甲藻分布趋势相似。研究结果为生物标志物作为浮游植物种群结果替代指标并为利用柱状样中的生物标志物研究古生态提供现代依据。

Multi-biomarkers have been applied for the reconstruction of phytoplankton productivity and community structure. This study reports phytoplankton biomarker ratios in surface sediments sampled during the second China arctic expedition from the western Chukchi Sea in the summer of 2003 and evaluates their potential as community structure proxies. The total biomarkers（sum of brassicasterol, dinosterol, alkenones） in the surveyed area were 20-3 149 ng/g, the average value was 1 010 ng/g. The distributions of biomarkers also indicate the primary productivity in the Chukchi shelf was higher than the Chukchi plateau. The brassicasterol to dinosterol ratios for different stations have an obvious diversification, but all stations show the brassicasterol is in the ascendant. At the station of the Chukchi shelf, diatom is the mainly phytoplankton, the brassicasterol accounts for 42% to 74% of the total biomarkers, and the proportion of dinosterol is 17% to 37% in the total biomarkers. On the plateau, the dominant phyto- plankton is also diatom, but the ratio of dinosterol and coccolithophore has a significantly. In the Canada Basin, dinosterol and coccolithophore are the dominant phytoplankton, diatom is not the predminant population and this result is in accord with phytoplankton distribution patterns obtained by other methods such as microscope. An important modern basis that these biomarkers can be used as proxies for community structure is prcvided, and it also suggests that this method can be used for community structure recon- struction for the sediment cores.