In order to understand the composition and structural characteristics,spatiotemporal distribution pattern and key impact drivers of phytoplankton communities in the Yangtze River Estuary,the characteristics of phyto-plankton communities and the relationship between the characteristics of phytoplankton communities and influencing factors were explored based on the survey data of phytoplankton in the Yangtze River Estuary in August(summer)and November(autumn)from 2018 to 2020 by community diversity analysis indicators and generalized additive model(GAM).The results showed that a total of 185 species of phytoplankton were collected in 8 phyla,99 gene-ra,with the dominant species mainly including Skeletonema costatum,Aulacoseira granulata,Melosira sulcata,Cy-clotella sp.and Chlamydomonas sp.,and the main phytoplankton groups including Bacillariophyta,Cyanophyta and Chlophyta,in which Skeletonema costatum had long been overwhelming.There were significantly higher abun-dance and species of phytoplankton in summer than those in autumn(P<0.05).In autumn,however,phytoplank-ton communities showed higher diversity index and richness index and more evenly distributed.Spatially,the aver-age phytoplankton abundance showed the distribution pattern of East Beach>South Branch>North Branch as a whole.The GAM analysis indicated that water temperature(Tem),pH and total nitrogen to total phosphorus ratio(TN/TP)were the environmental factors(P<0.05)significantly affecting the abundance distribution of phyto-plankton in the Yangtze River Estuary in summer,with the maximal contribution rate of 71.86%from TN/TP.Sa-linity(Sal),dissolved oxygen(DO)and chemical oxygen demand(CODMn)were found to be the environmental factors(P<0.05)significantly affecting the abundance distribution of phytoplankton in the Yangtze River Estuary in autumn,especially the DO contribution up to 48.48%.The findings indicate that there are seasonal differences in the community composition,structure,pattern and influencing factors of phytoplankton in the Yangtze River Es-tuary,which provides references for understanding of the dynamics of phytoplankton resources in the Yangtze River Estuary.
关键词
浮游植物/群落特征/影响因素/广义加性模型/长江口
Key words
phytoplankton/community characteristics/influencing factor/generalized additive model/Yangtze River Estuary