Impact of microecological agents on water environment restoration and microbial community structures of trench system in a Baiyangdian wetland ecosystem.

Aims To evaluate effect of periodic application of effective microorganisms (EM) bacteria and calcium peroxide on water environment restoration of a trench wetland ecosystem and its impact on microbiota in water and sediment. Methods and results The EM bacteria and calcium peroxide were alternately sprayed into the trench water and changes in the physicochemical indices of water and sediment, and in microbiota structure were subsequently investigated. Alternately spraying of calcium peroxide and EM bacteria improved the water quality, especially in terms of the dissolved oxygen and transparency of water body, and could further reduce the levels of total nitrogen, total phosphorus, and ammonia nitrogen. At the same time, the microbiota structure of the water body was significantly changed by spraying with calcium peroxide and EM bacteria, and the relative abundances of Pseudanabaena, Legionellaceae, Planktothrix, Planctomyces, Phenylobacterium, Rhodobacter, Rhodoferax, and Aquirestis were significantly increased. However, there was no significant effect on the physicochemical indexes and microbiota composition of the sediment. Conclusions The water quality of the Baiyangdian trench could be significantly restored by regular sprinkling of calcium peroxide and EM bacteria. Significance and impact of study The results provide an effective technical method for the restoration of trench wetland water.