Abstract:
Lotus-fish co-culture is a typical ecological farming system. To explore the effects of lotus-fish co-culture on environmental factors and microbial community in aquaculture ponds, we compared the changes in water environmental factors, microbial diversity and community composition in the water and sediment environment between lotus-fish co-culture and conventional pond culture, through field investigation and metagenome sequencing technology. The results indicate that the nutrient contents decreased significantly but the dissolved oxygen increased significantly in the lotus-fish co-culture pond. Besides, the total nitrogen in the sediment decreased from 2.323 mg·kg
−1 to 2.017 mg·kg
−1 averagely. The total phosphorus decreased from 0.447 mg·L
−1 to 0.110 mg·L
−1 but the dissolved oxygen increased from 7.253 mg·L
−1 to 8.790 mg·L
−1 averagely. Pseudomonadota
, Actinomycetota and Candidate_division_NC10 were significantly enriched in the lotus-fish co-culture pond (
p<0.05). In contrast, Cyanobacteriota and Planctomycetota were enriched significantly in the conventional pond. On genus level, it was found that
Microcystis,
Polynucleobacter, unclassified Rhodocyclaceae were the key microbial taxa contributing most to the variations in microbial community composition;
Microcystis, unclassified Deltaproteobacteria, unclassified Desulfobacterales were the key microbial taxa contributing most to the variations in microbial community composition in the sediment. RDA analysis shows that pH, NO
3-N, DO, NH
4-N and TOC were determined as the key environmental factors shaping microbial community composition in the water and sediment. These results indicate that lotus-fish co-culture can improve the pond water quality effectively and promote the development of probiotic microbial taxa in water and sediment, which is important in maintaining the stability of ecological environment in aquaculture ponds.