Spatiotemporal Variations in Microbial Community Structure and Assembly Mechanisms Within Recirculating Aquaculture...

Area of Science:

• Aquatic microbial ecology
• Aquaculture systems science
• Environmental microbiology

Background:

• Mandarin fish (Siniperca chuatsi) aquaculture relies on Recirculating Aquaculture Systems (RAS).
• Understanding microbial community dynamics is crucial for RAS ecological function and stability.
• The role of microbial succession in RAS for Mandarin fish is poorly understood.

Purpose of the Study:

• To analyze microbial community structure, assembly, networks, and functions in RAS for Mandarin fish.
• To investigate temporal and spatial variations in microbial communities.
• To provide insights for optimizing RAS management.

Main Methods:

• 16S rRNA high-throughput sequencing was used to analyze microbial communities.
• Community characteristics, assembly mechanisms, co-occurrence networks, and potential functions were assessed.
• Sampling occurred across different functional zones and culture cycles.

Main Results:

• Microbial alpha diversity decreased temporally during later culture stages (T4) due to stress, then recovered (T5).
• Significant spatial differences in microbial composition were observed, influenced by environmental specificity.
• Stochastic processes dominated microbial assembly, with limited dispersal in certain zones (GC, LHC).
• Chemoheterotrophy was the core metabolic function, and nitrogen transformation pathways shifted over time.
• Microbial interactions were mainly competitive, with network structure evolving from loose to modular.

Conclusions:

• Microbial community succession in RAS is influenced by both temporal and spatial factors.
• Stochastic assembly and habitat barriers shape microbial distribution.
• Understanding these dynamics is key to managing nitrogenous waste and ensuring RAS stability for Mandarin fish culture.