2015年春季桑沟湾浮游植物群落研究

摘要

A comprehensive survey including hydrology, biology, and chemistry was carried out in the Sanggou Bay (122.48°E–122.64°E, 37.04°N–37.14°N) during spring, 2015. The species composition, abundance, and dominant species were analyzed by the Uterm?hl method. The results showed a total of 70 taxa belonging to 36 genera of four phyla were identified. Bacillariophyta and Dinophyta were the dominant phytoplankton groups, and they were mostly typical warm neritic species. The other two groups, Cyanophyta and Chrysophyta, were recorded more sporadically. The diatoms were primarily composed of Paralia sulcata and Thalassiosira excentrica, while the dinoflagellates were composed of Protoperidinium bipes. The cell abundance of phytoplankton ranged from 3 to 417.4 × 103 cells/L with an average value of 130.8 × 103 cells/L. Compared with previous studies, the species richness of the phytoplankton decreased. The horizontal distribution of the phytoplankton cell abundance in this area was dependent on diatoms dis-tribution, which was low around the central area and high in the western and eastern points of the studied area. The vertical distribution of phytoplankton cell abundance showed a decreasing trend with an increasing depth in the sub-surface and then reached a maximum in the bottom layer. The Shannon-wiener diversity index and Pielou's evenness index of the phytoplankton community ranged from 0.486 to 2.305 and 0.172 to 0.849, with average values of 1.250 and 0.462, respectively. Because the high value zones of Shannon-wiener diversity index and Pielou's evenness index were in good correspondence with the low phytoplankton cell abundance area, the emergence of preponderant species would reduce the diversity of phytoplankton.%2015年春季,在桑沟湾海域(122.48°E~122.64°E,37.04°N~37.14°N)21个站位进行了水文、生物和化学的综合调查,应用Uterm?hl方法对调查海域浮游植物的物种组成、细胞丰度、优势物种以及群落多样性等相关生态特征进行了分析.结果表明,本次调查共鉴定浮游植物4门36属70种,主要由硅藻和甲藻组成,也有少数的蓝藻和金藻出现,浮游植物生态类型主要为温带近岸型.硅藻主要优势种为具槽帕拉藻(Paralia sulcata)和离心列海链藻(Thalassiosira excentrica);甲藻主要优势种为双刺原多甲藻(Protoperidinium bipes).调查海域浮游植物细胞丰度范围为3×103~417.4×103个/L,平均值为130.76×103个/L.相比历史资料,桑沟湾浮游植物物种数整体呈下降趋势.浮游植物细胞丰度的平面分布主要由硅藻分布所决定,呈现中部较低,逐渐向西部与东部增加的趋势;其垂直分布呈现随水深的增加,先降低后升高的趋势.浮游植物群落Shannon-Wiener多样性指数范围为0.486~2.305,平均值为1.25;Pielou均匀度指数的区间范围为0.172~0.849,平均值为0.462.由于Shannon-Wiener多样性指数和Pielou均匀度指数的高值区与浮游植物细胞丰度的低值区相对应,从而说明优势种的出现会降低浮游植物的多样性.