桑沟湾浮游植物粒径结构及其与环境因子的关系

Distribution of size-fractionated phytoplankton and its relationship with environmental variables in Sanggou Bay

中文关键词: 叶绿素a  粒径结构  冗余分析  桑沟湾

英文关键词: Chlorophyll-a  Size fraction  Redundancy analysis  Sanggou Bay

中文摘要:

      于2017年4、7、11月和2018年1月4个航次调查了桑沟湾浮游植物粒径结构的时空分布，并分析了粒径结构与主要环境因子的关系。结果显示，桑沟湾海域表、底层Chl-a浓度的年变化范围分别为0.743.27和0.813.66 µg/L，平均值分别为(1.90±1.28)和(2.01±1.29) µg/L，存在极显著的季节差异(P<0.01)和空间分布的不均匀性。从粒径结构来看，小型浮游植物是春季表、底层浮游植物的主要贡献者，贡献率分别为54.05%和58.08%，夏、秋和冬季均是微型浮游植物占优势地位。冬季和春季微微型浮游植物的贡献率较小，但夏季和秋季的贡献率显著增多，夏季表、底层贡献率分别达24.46%和20.70%；秋季表、底层贡献率分别达35.88%和40.77%。冗余分析(Redundancy analysis, RDA)结果表明，温度(T)是影响浮游植物粒径结构的主要环境因子。溶解氧(DO)对微微型浮游植物占总浮游植物的比例有显著影响；微型浮游植物所占比例受亚硝酸盐(NO2)、铵盐(NH4)等影响显著；小型浮游植物对总浮游植物的贡献主要受温度影响，呈正相关。研究结果为深入认识桑沟湾养殖生态系统浮游植物的粒径结构、准确评估滤食性贝类的养殖容量提供了基础数据。

英文摘要:

      Surveys have been conducted to investigate the spatial and temporal distribution of size-fractionated phytoplankton and other environmental variables in Sanggou Bay in four seasons for the period covering April 2017 until January 2018. Results showed that chlorophyll a concentration in the surface and bottom layers ranged from 0.74 to 3.27 µg/L and from 0.81 to 3.66 µg/L, respectively, with average values of (1.90±1.28) and (2.01±1.29) µg/L, respectively. There were significant differences in chlorophyll a concentration (P<0.01) and spatial distribution between seasons. In spring, microphytoplankton was the most abundant, accounting for 54.05% and 58.08% of the total phytoplankton in the surface and bottom layers, respectively. In summer, picophytoplankton was the most abundant, accounting for 24.46% and 20.70% of total cholorophyll a in the surface and bottom layers, respectively. In autumn, picophytoplankton accounted for 35.88% and 40.77% of total chlorophyll a in the surface and bottom layers, respectively. The contribution of picophytoplankton was low in winter and spring but increased significantly in summer and autumn. Redundancy analysis (RDA) results show that temperature is the main environmental factor affecting the size structure of phytoplankton. Dissolved oxygen had a significant effect on the percentage of picophytoplankton to total phytoplankton. The percentage of nanophytoplankton correlated with NO2 and NH4. There was a significant positive correlation between temperature and the percentage of microphytoplankton. This study provides basic knowledge for understanding the size structure of phytoplankton and estimating the carrying capacity of filter-feeding shellfish in the aquaculture ecosystem in Sanggou Bay.