Manipulating the phytoplankton community has the potential to create a stable bacterioplankton community in a shrimp rearing environment

Abstract

‘Greenwater’ technology is a routine application in aquaculture to manage rearing environment. However, the regulation effects of phytoplankton community of green water on the rearing water microflora and rearing shrimps is unclear. To fill this gap, we explored the dynamics of bacterioplankton community and the growth performance of rearing shrimp in two greenwater systems with different phytoplankton communities. Our results showed significant differences in the bacterioplankton communities between green water with phytoplankton communities dominated by diatoms (DIA) and chlorophytes (CHLO). Specifically, DIA green water harbored abundant pathogenic bacteria affiliated to opportunistic Gammaproteobacteria, while phytoplankton of CHLO recruited probiotic bacteria affiliated to Rhodobacterales and Nitratireductor. Notably, network interactions comparison revealed that the bacterioplankton communities in CHLO were more stable than those in DIA. Additionally, the shrimps reared in CHLO were healthier and grow faster (p < .05) relative to those rearing in DIA. Furthermore, we screened a Nannochloropsis oculata–bacteria consortium from CHLO rearing environment with non-pathogenic r-strategic bacteria affiliated to family Rhodobacterales which could prevent opportunistic bacteria affiliated to order Alteromonadales by competitive exclusion, and validated its modulation capability upon bacterioplankton community and predicated interactions though a microcosmic experiment. These findings expand our understanding of the microbial ecology of ‘greenwater’ technology, and offer a frame to identify beneficial algae-bacteria consortia which have a potential to optimize and develop microbial management strategies.