Contrasting microbial community composition and function perspective of the biofilms in shrimps (Macrobrachium...

Biofilm microbial communities and the water quality environment were studied in either carrier biofilm in isolation, or in combination with shrimp (Macrobrachium nipponense) from Baiyangdian Lake. Use of biofilm treatment effectively improved the water quality environment, however, the content of NH₄-N, TN, and TP increased by 2.49, 1.93, and 0.94 folds, with the addition of high shrimp populations into the aquatic environment over a long-term period (75 d). The relative abundance of dominant phyla in carrier biofilms was Proteobacteria (50.20%), Cyanobacteria (23.31%) and Planctomycetes (8.14%) in control group (no shrimps). The relative abundance of Cyanobacteria decreased by 60.6%, whereas Planctomycetes increased by 1 folds with the high shrimp population addition. In addition, the inclusion of low density shrimp populations decreased by 21.1%, and 31.6% in NH₄-N and TP concentrations compared to controls over a short-term period (15 d), respectively. The abundance of Planctomycetes increased by 92.9% with the addition of low shrimp populations on 15 d. Our results showed that the addition of low shrimp population (286 animals/m²) could improve the water quality environment containing carrier biofilm according to the regulation of the bacterial diversity in the biofilm system in short-term period (15 d).