2010秋季东海今生颗石藻的空间分布

根据2010年11月东海29站位所采集108个样品偏光镜检分析结果显示:调查区共发现26种今生颗石藻,优势种为赫氏艾密里藻(Emiliania huxleyi)、大洋桥石藻(Gephyrocapsa oceanica)、卡特螺旋球藻(Helicosphaera carteri)和粗壮环翼球(Algirosphaera robusta)等.水体中今生颗石藻丰度为0-76.562个/mL,平均值为18.641个/mL;颗石粒丰度0-4506.47个/mL,平均值为613.44个/mL,今生颗石藻在表层和底层均呈斑块状分布,海盆区站位丰度较近岸站位下降明显,但物种丰富度明显增多；颗石球丰度最大值站位发生在硅藻水华站位.将研究区域划分为3个断面进行分析:PN断面、沿岸流断面和黑潮断面.比较显示,PN断面的空间分布差异性较大,赫氏艾密里藻具有最高丰度的颗石粒和颗石球.沿岸流断面颗石粒/颗石球、黑潮断面中颗石粒(除底层外),自表至底随水深增加有轻微增加趋势,黑潮断面颗石球丰度高值区集中于25-80 m之间.结合历史环境资料,分析得出东海调查期水体混合、泥沙再悬浮以及硝酸盐浓度是控制今生颗石藻物种丰富度与物种特异分布的主要因子；今生颗石藻在不同环境中具有不同的生活策略,其空间分布特征随取样季节和海区不同有较大变化.

The distribution of living coccolithophore in East China Sea in autumn, 2010

Living coccolithophores (LC) are important in marine ecology, biogeochemistry, and especially the carbon cycle. Our chief aim in investigating the geographic distribution of LCs has been to provide data to help understand their roles. We investigated LCs in the East China Sea (ECS) from 7 October to 5 November 2010. Seawater samples from CTD arrays were filtered through 25 mm cellulose mixed-ester membrane filters on board as soon as possible, and dried. Then a piece of the membrane was cut out and, using neutral balsam, mounted beneath a cover glass. The samples were observed with a polarizing microscope at 1000× magnification. Twenty-six taxa were identified at different depths from 108 samples in ECS, the dominant species being Emiliana huxleyi, Gephyrocapsa oceanica, Helicosphaera carteri and Algirosphaera robusta. The abundance of coccoliths and cells ranged from 0-76 cells/mL and 0-4500 coccoliths/mL, the average being 18 cells/mL, 613 coccoliths/mL, respectively. The distributed pattern of LCs and coccoliths in surface and bottom layers were patchy. The outer areas of the sea basin had more species but showed less abundance than the inner area. The highest abundance was found at a station supporting a diatom bloom. We further observed the distribution of: total coccoliths; total cells; coccoliths and cells of E. huxleyi and G. oceanica; and compared these distributions among PN sections (PNs, starts from the Changjiang River estuary (121.5°E, 31.5°N) to the south-east corner of Ryukyu (128.23°E, 27.45°N)), Coastal Current sections (CCs) and the Kuroshio Current sections (KCs). PNs supoorted the highest abundance except for the cells of E. huxleyi. The distributions of coccoliths and cells between CCs and KCs (except in the bottom-most layer) showed slightly higher abundances in deep than in surface water. At the KC stations, however, coccolithophorids thrived between 25m and 80m. Our observations suggest that water-column mixing, sediment resuspension and nitrate concentration affect the distribution patterns of both species numbers and individual species.