Seasonal Variation Characteristics of Phytoplankton Community Structure and Environmental Impact Factors in the Weizhou Is-land,Guangxi
In order to understand the seasonal variation characteristics of phytoplankton community structure and its environmental impact factors in the habitat of Balaenoptera edeni in Weizhou Island,Guangxi,and to analyze the relationship between the seasonal variation of phytoplankton community structure characteristics and the seasonal migration of B.edeni,the phytoplankton in the habitat of B.edeni in Weizhou Island,Guan-gxi were systematically investigated in January(winter),April(spring),August(summer)and November(autumn)in 2022.A total of 115 species of phytoplankton belonging to 54 genera and 3 phyla were identified throughout the year.The species composition was dominated by Bacillariophyta(93 species)and Pyrrophyta(19 species).The seasonal difference of phytoplankton species composition was not obvious,but the dominant species changed significantly,and the dominant groups also changed greatly.Among them,Bacillariophyta was the most dominant group in winter and spring,and the dominant species also belonged to Bacillariophy-ta.However,in summer and autumn,the dominant groups changed to be composed of Bacillariophyta,Pyrro-phyta and Cyanophyta.The density of phytoplankton cells also changed greatly,with the highest in spring,the second in winter,and the lowest in summer and autumn.Redundancy Analysis(RDA)of phytoplankton and environmental factors showed that nutrients,Water Temperature(WT)and Salinity(S)were the main environmental factors affecting the seasonal variation of phytoplankton cell density and dominant species structure.The migration of B.edeni into Weizhou Island in winter and spring,and out of Weizhou Island in summer and autumn were consistent with the seasonal variation of phytoplankton cell density.Phytoplank-ton,as a primary producer,may affect the migration of the top trophic marine organism B.edeni through the upward control of the food web.