象山港赤潮期浮游生物生态特征的分析

ECOLOGICAL EIGENVALUE ANALYSES OFPLANKTON OF RED TIDES OCCURREDIN XIANGSHAN SOUND, ZHEJIANG

从浮游生物群落动力学角度对1988年象山港发生的三次赤潮期浮游生物生态特征进行了分析。采用了生物量、优势度、聚集强度测度及群落结构的多项指数。结果表明:1月份引发两次赤潮的生物均为骨条藻(Skeletonema costatum),12月份的为短角弯角藻(Eucampia zoodiacus)。三次赤潮发生时浮游动物均以墨氏胸刺水蚤(Centropages mcmurrich)占明显优势。赤潮发生时,浮游植物个体总量高于非赤潮时10~3倍以上,优势种比势度达80％～90％,并呈高度的聚集性分布;同时丰富度、多样度、均匀度指数降低,而单纯度增大。如果赤潮发生时伴随着浮游动物也有很大的种群数量,将导致浮游动、植物群落结构以及种群数量恢复变慢。

Red tide occurred three times in 1988, twice in January and once in December, in the Xiangshan Sound, Zhejiang Province. Based on the data from monthly-conducted planktonic survey, the eigenvalue analyses of the three red tides were made using indices of biomass, dominance, aggregated intensity and communical structure and focusing on the plank-tonic status pre-, during and post-algal-blooms. It is showed the two red tides occurred in January at Huangdun Harbor and Xihu Harbor were mainly caused by Skeletonema costatum, while the third one in December at Xihu Harbor almost soly by Eucampia zoodiacus. Centropages mcmurrich was the dominant zooplankton found in the three accidents. The quantity of phyto-plankton during red tides was 1000 times greater than out of the red tides. The distribution of dominant species was highly aggregated and the dominance ranged between 80%-99%. Communical indices of aboundance, diversity and homigeneity were low during the red tide outbursts whereas the monoh-omogeneity was high. It is indicated that if the zooplanktonic populations grow too large during red tide period, the recovery of community structure of both phytoplankton and zooplankton disturbed or toppled in the outburst would be retarded seriously.