With a stimulated wetland system,the ecological distributions and species changes of bacteria and algae in the different treatment blocks were studied.The species and numbers of bacteria and algae changed according to the concentration decline of pollutants.In the different treatment blocks,the bacteria species of the biofilms and algae changed from pollution tolerant ones to more diverse species.It was found that that algae were good biological indicators of water quality.The Margalef diversity index incr...