Distribution Characteristics of Phytoplankton in the Estuary of Yellow River During Summer

Investigations,which included 7 voyages and 200 positions,were made every summer from 2004 to 2010.According to the investigated.materials,this paper studied the phytoplankton's specific compostion,the abundance,the dominant species and the temporal and spatial variation of diversity index.The result showed that a total of 137 phytoplankton species were collected,the range of abundance was from 71.51 × 104ind/m3 to 2 296.31 × 104ind/m3.The composition of dominant species greatly changed,while higher frequency dominant species were Skeletonema costatum,Chaetoceros laciniosus,Chaetoceros lorenzianus and Thalassionema nitzschioide.The diversity index showed an upward trend from near coast to off coast,and most low value areas were near the estuary.The clustering result showed that the phytoplankton community could be divided into three groups.