Abstract:Community structure and spatial distribution of the particle-attached bacteria along environmental gradient in the Pear River Esturary, as well the influencing factors, were studied by PCR-DGGE and canonical correspondence analysis. The DGGE profiles showed significant spacial succession of the particle-attached bacteria along environmental gradient. Some bands from DGGE gel were shared by two or more stations, while the others belonged to the special station. The bacterial communities in S4 and S5, differed significantly from those in adjacent stations, with transitional form from the freshwater-seawater mixing zone to seawater zone. Sequence analysis of nineteen major bands from DGGE profiles revealed that two sequences were highly similar to those of the cultured bacteria (≥99%), and the others were similar to those of the uncultured bacteria (91%～100%). Proteobacteria and bacteroidetes were dominant populations in all stations, particularly proteobacteria (78.9%). Canonical correspondence analysis indicated that nitrogen nutrient and salinity were the major contributing parameters for the spatial distribution of the particle-attached bacterial community structure in the Pear River Esturary.
