西湖湖西浮游与着生藻类季节变化及相互关系

SEASONAL VARIATION OF PHYTOPLANKTON AND PERIPHYTON AND THEIR RELATIONSHIPS IN THE WESTERN REGION OF THE WEST LAKE

2014年11月至2015年8月调查了西湖湖西沿岸带浮游藻类和不同基质(植物、石块和底泥)上着生藻类的群落结构及季节变化,分析了着生丝状藻与浮游丝状藻的相互关系以及它们与环境因子的相关性,探讨湖西生态修复过程中季节性暴发的丝状藻水华的原因。结果表明浮游藻类和植物、底泥、石头上着生藻类中均以硅藻门种类数(分别占52.5%、60.4%、86.7%和72.7%)最多,蓝藻门(分别占10.1%、8.9%、6.7%和15.2%)和绿藻门(分别占26.3%、19.8%、5.6%和10.6%)次之,其他门类相对较少,浮游藻类与着生藻类优势种季节差异较大。附植丝状藻密度显著高于附泥和附石丝状藻,且狐尾藻上着生丝状藻密度与浮游丝状藻密度呈显著正相关,表明狐尾藻着生丝状藻可能是浮游丝状藻较重要的来源之一,该结果可为西湖丝状藻水华的控制提供一些参考。相关性分析表明,着生藻类和丝状藻与各理化因子(水深、透明度、溶解氧、水温、p H、TN、SRP、TP等)均无显著相关性。

This study investigated the community structure and seasonal variation of phytoplankton and periphyton ondifferent substrates （macrophytes, stone and sediment）, and analyzed the relationships between planktonic and periphy-tic filamentous algae and their interactions with environmental factors in the western littoral zone of West Lake fromDecember, 2014 to August, 2015, and also discussed the cause of seasonal outbreak of filamentous algal bloom duringthe process of the ecological restoration. The results showed that bacillariophyta has occupied the first place （52.5%,60.4%, 86.7% and 72.7%, respectively） among the algal species of different habitats （phytoplankton, epiphyton,epipelon and epilithon）, and that Cyanophyta （10.1%, 8.9%, 6.7% and 15.2%, respectively） and Chlorophyta （26.3%,19.8%, 5.6% and 10.6%, respectively） came second and third, and that of others were relatively low. The compositionand seasonal pattern of dominant species of phytoplankton and periphyton on different substrates were quite different.The density of filamentous algae on macrophytes was significantly higher than that on sediment and stone. Moreover, asignificant positive correlation was found between filamentous algae in planktonic habitat and on Myriophyllum. Thissuggest that the filamentous algae on Myriophyllum might be one of vital sources in planktonic habitat. The correlationanalysis elucidated that periphytic algae and filamentous algae had no significant correlation with all physical andchemical factors monitored （water depth, transparency, dissolved oxygen, water temperature, pH, total nitrogen, solu-ble reactive phosphorus, total phosphorus, etc.）. These results provide reference for the control of abnormal prolifera-tion of filamentous algae in the West Lake.