Phytoplankton assemblages in Yangtze River Estuary and its adjacent water in autumn,2006

Water samples for phytoplankton were taken from grid survey stations around the Yangtze River Estuary and its adjacent water from November 7 to 21,2006.Phytoplankton assemblages and cell abundance were reported in this paper.The primary phytoplankton group was diatoms and the secondary group dinoflagellates.There were also a few species belonging to Chrysophyceae,Chlorophyceae and Cyanophyceae,respectively.The dominant species were Thalassiosira rotula and Skeletonema costatum,respectively.The cell abundance of phytoplankton ranged from 0.13 to 59.69 cells/L with the average being 4.39 cells/L.The areas of high cell abundance were at the Yangtze River mouth and offshore of the survey area,respectively.The maximum phytoplankton cell abundance was at 20-m water layer.Section distributions were briefly described for S.costatum and T.rotula.The diazotrphic flora Trichodesmium thiebautii were mainly in the surface water of the eastern part of the survey area.Two phytoplankton provinces in the survey area were discriminated by cluster analysis of the phytoplankton assemblages.