流沙湾浮游生物的群落结构与时空分布

Community Structure and Temporal and Spatial Distribution of Plankton in Liusha Bay

于2008年3月至2009年2月对流沙湾浮游生物的群落结构及其动态变化特征进行了研究,结果表明,流沙湾共有浮游植物27属,隶属于5个门,其中硅藻门20属,绿藻门3属,蓝藻门2属,金藻门1属,甲藻门1属,角毛藻(Chaetoceros)、骨条藻(Skeletonema costatum)和菱形藻(Nitzschia sp.)为优势种;浮游植物生物量变化在0.11～23.63 mg L-1之间,平均为3.72 mg L-1,细胞密度平均为1.324 7×104个L-1。流沙湾共有浮游动物19种,其中原生动物10种,桡足类6种,枝角类、多毛类和轮虫类各1种,优势种类为原生动物中的拟铃虫(Tintinnopsis)、薄铃虫(Leprotintinnus),桡足类中的哲水蚤(Calanus),浮游幼体中的无节幼体(Nauplius);浮游动物生物量在0.08～7.24 mg L-1之间,平均为2.04 mg L-1,密度平均为8 186个L-1。水体交换能力差、大规模贝类养殖以及养殖造成的水体污染等因素,导致流沙湾浮游生物量、物种多样性指数、均匀度指数、丰富度指数均处于较低水平,但有明显的水平分布和月变化。

Based on plankton samples collected from Mar 2008 to Feb 2009 at nine research stations in Liusha Bay, the community structure and dynamics of plankton were studied. A total of 27 genus of phytoplankton identified in Liusha Bay belong to five phyla： twenty Bacillariophyta genus, three Chlorophyta genus, two Cyanophyta genus, one Chrysophyta genera, and one Pyrrophyta genera. The dominant species were Chaetoceros sp., Skeletonema costatum, Nitzschia sp. Phytoplankton biomass varied from 0.11 to 23.63 mg·L^-1 with the average value 3.72 mg·L^-1; the average cell density were 1.324 7× 10^4 cells·L^-1. There were nineteen species of zooplankton identified, which included ten Protozoa species, six Copepod species, one Cladocera species, one Polychaeta species, and one Rotifera species. Many of the four dominant species belonged to the Protozoa and Copepod, including Tintinnopsis, Leprotintinnus, Calanoida and Nauplius. The zooplankton biomass varied from 0.08 to 7.24 mg·L^-1, with the average 2.04 mg/L, and the average value of cell density were 818 6 cell·L^-1. Changed variety of the plankton biomass, species diversity index, evenness index and richness index from its original high levelto the low level reflects the adverse impact of human activities including excessive cultivation, water pollution and habitat degradation. However, the community structure and dynamics of the plankton were significantly affected in different months and horizontal zones.