The Characteristics of Microbial and Phytoplankton Community and Water Quality in the Guangzhou Segment of Pearl River

Termporal and spatial change of cultural bacteria,coliform,fecal-coliform and phytoplankton were investigated at two fixed sampling sites(Zhongda and Yuzhu port)in the Guangzhou segment of Pearl River from May 2008 to April 2010.Results indicated that mean concentrations of total nitrogen were(7.02±4.18) mg/L and(8.03±5.02) mg/L,total phosphorus were(0.47±0.29) mg/L and(0.50±0.27) mg/L at two sites,respectively.The abundance of culturable bacteria ranged from 103-105 cfu/mL.The abundance of coliform and fecal-coliform were 102-103 cfu/mL respectively.The two sampling stations were characterized by high abundance of phytoplankton with abundance ranged from(1.50-13.17)×106 cells/L.Bacillariophyta,Chlorophyta and Cyanobacteria were the three main dominant groups in this segment.The highest phytoplankton abundance occurred in autumn,and the minimum density appeared in summer.The quantitiy of fecal-coliform was still away from the Ⅴcategory of environmental quality standard for surface water,which indicate the organic pollution was serious.These results demonstrated that the water quality could be classified as poor quality and eutrophication in this river segment.