海河入海口表层水体浮游生物群落特征及与环境因子的相关性研究

Study of the Community Characteristics of Plankton and Their Correlation with the Environmental Factors in Surface Water in Haihe Estuary

浮游植物是水域生境的初级生产者之一,浮游动物是水生食物网中承上启下的关键环节,它们都在水生生态系统的物质循环和能量流动过程中发挥着举足轻重的作用。研究浮游生物群落结构变化及其与环境因子的关系,对了解水生生态系统的变化、生态过程等有着重要意义。为了研究海河入海口浮游生物的群落特征以及与水环境因子的关系,于2014年6月(夏季)和2015年1月(冬季)进行了两次调查采样,分析了海河入海口区域表层水体的浮游动、植物丰度以及环境因子。结果表明,调查期间共发现浮游植物55种,浮游动物19种。夏季浮游植物平均丰度为2.98×107 cells·L^(-1),冬季为6.0×106 cells·L^(-1);夏季浮游动物平均丰度为53.56 inds·L^(-1),冬季为36.76 inds·L^(-1)。环境因子方面,夏季平均溶解氧质量浓度为4.10 mg·L^(-1),高于冬季的3.72 mg·L^(-1)。冬季平均盐度为18.98‰,略高于夏季的17.09‰,两个航次盐度的空间分布近乎一致。夏季平均p H为8.25,冬季为8.17,夏季略高于冬季。铵态氮(NH4+-N)、硝态氮(NO_3-N)、亚硝态氮(NO_2-N)和总氮(TN)平均水平均为夏季高于冬季,但在构成上却表现出较大的时空差异,夏季NH_4^+-N和NO_2-N占优势,冬季NH_4^+-N居于主导。夏季总磷(TP)平均水平为14.03 mg·L^(-1),远高于冬季的0.03 mg·L^(-1)。相关性分析表明,温度对浮游动、植物群落发展均具有显著的促进作用。高盐度不利于浮游植物生长繁殖,但对浮游动物有一定的积极影响。冬季浮游动物对浮游植物的摄食压力增大,下行控制效应突出。

Phytoplankton plays an important role as one of the primary producers in the water habitats, and zooplankton serves as thekey taxa connecting link beteen lower and upper trophic level. Phytoplankton and zooplankton play an important role in circulationof materials and flow of energe in the aquatic ecosystem. Knowledge of plankton community dynamics and its relationship withenvironmental factors is crucial in understanding the changes in aquatic ecosystems. In order to explore the characteristics ofplankton community structure and their relationships with environmental factors in surface water in haihe estuary, we investigatedthe species composition, abundance, spatial distribution of plankton and environmental factors in haihe estuary in June 2014（summer） and January 2015 （winter）. There were 55 phytoplankton and 19 zooplankton species identified. The abundance ofphytoplankton in summer was higher than it in winter, and the average abundance of the phytoplankton were 2.98×107 cells·L-1 and6.0×106 cells·L-1 respectively. Having the same trend, the abundance of zooplankton in summer was also higher than it in winter, andthe average abundance of the zooplankton were 53.56 inds·L-1 and 36.76 inds·L-1 respectively. The dissolved oxygen massconcentration in summer was higher than it in winter, and the average do mass concentration were 4.10 mg·L-1 and 3.72 mg·L-1respectively. The salinity in winter was higher than it in summer appreciably, were 18.98‰ and 17.09‰ respectively, and the spatialdistribution of salinity in summer and winter were almost unanimously. The average pH in summer was higher than it in winterappreciably, and the average pH were 8.25 and 8.17 respectively. The average levels of TN, NH3-N, NO2-N and NO3-N were higherin summer than them in winter, but the component ratio of nitrogen changed largely in spatial and temporal distribution. NH3-N,NO3-N dominated in summer, while NH3-N in winter. The TP in summer was much higher than it in winter, and the average level ofTP were 14.03 mg·L-1 and 0.03 mg·L-1 respectively. According to correlation analysis, the communities of phytoplankton andzooplankton were promoted significantly by temperature. The growth and reproduction of phytoplankton were adversely affected byhigh salinity, while those of zooplankton just the reverse. The grazing pressure exerted on phytoplankton by zooplankton was high inwinter, and the top-down effect highlighted significantly.