A cruise was taken in October 2015 to determine phytoplankton size structure near Zhangzidao Island and adjacent waters. The surface and bottom distribution of size-fractioned phytoplankton and its correlation with environmental factors were examined. The concentration of total chlorophyll a,microplankton( >20μm),nanoplankton( 2—20μm),and picoplankton( 0.45—2μm) were measured in the surface and bottom layers. In the surface layer,the total chlorophyll a concentration ranged between 0.52—1. 25μg/L with an av...