Successional patterns of bacterial communities and their functions in shrimp aquaculture pond water across farming phases

Abstract

Microorganisms, as integral components of food webs, play key roles in regulating the aquatic environment in shrimp farming. However, the abundance and functional diversity of bacteria in shrimp aquaculture ponds and the factors shaping their distribution patterns remain largely unknown. We investigated the temporal and depth changes of the bacterial communities in water columns of shrimp ponds in the Min River estuary, southeastern China. Proteobacteria was the most dominant phylum throughout the aquaculture period. The differences in the pattern of variation in bacterial communities among three water column depths were minimal. As a potential pathogen, the genus Vibrio gradually increased in relative abundance from the initial to the final farming phase. Network analysis indicated that the degrees of species segregation were higher, and the average path lengths shorter, during the middle and final farming phases compared with the initial farming phase. This suggested that environmental stimuli are more efficient at reaching the whole network and are potentially more susceptible to external disturbance during the latter two phases. Anaerobic bacteria were most abundant during the middle and final farming phases. Salinity and chlorophyll a concentration were the variables most strongly correlated with the bacterial communities during all phases, and abiotic selection accounted for most of the total variation during the three farming phases. These findings contribute to a deeper understanding of the temporal changes in the composition and functional diversity of bacterial communities in coastal shrimp pond water columns and have implications for the effective and sustainable management of shrimp aquaculture systems.