Control of cyanobacterial blooms in different polyculture patterns of filter feeders and effects of these patterns on water quality and microbial community in aquacultural ponds

Abstract

Six experimental groups were established for a land-based enclosure experiment: Macrobrachium rosenbergii Monoculture group; M. rosenbergii and Hyriopsis cumingii polyculture group; M. rosenbergii and silver and bighead carp polyculture group; and M. rosenbergii, H. cumingii, and silver and bighead carp polyculture groups (GSBH1, GSBH2, and GSBH3) in different densities of H. cumingii. Each group had four replicates. Control of cyanobacterial blooms in different polyculture patterns and the effects of these patterns on water quality and microbial community were studied. Results showed that the silver and bighead carp polyculture could control cyanobacterial blooms. The H. cumingii and silver and bighead carp polyculture improved water quality, and the GSBH2 group had the best purifying effect. Moreover, different microbial communities were observed in the different polyculture patterns. The silver and bighead carp polyculture exerted obvious effect on microbial community, whereas H. cumingii only slightly affected microbial community. Water quality parameters that significantly influenced microbial community included Secchi depth transparency, total nitrogen content, total phosphorus content, total dissolved phosphate content, nitrite nitrogen content, chemical oxygen demand, and chlorophyll a content. Thus, microbial community could also serve as an indicator of nutrient levels of water bodies.