Impact of typhoon on nutrient contaminants, antibiotic resistance genes and microbial communities in mariculture tailwater treatment system.

Intensive marine aquaculture generates complex pollutants, including nutrients and, threatening marine ecosystems. Biological treatments are effective but vulnerable to disruptions, especially during typhoons, which alter water quality and microbial communities. This study examined a mariculture tailwater (MTW) treatment system in Hainan over a year, focusing on seasonal performance in nutrient and ARGs removal, microbial community dynamics, impacts of environmental changes on functional microorganisms, and interactions of hosts of antibiotic resistance genes. The system effectively removed NH4+-N (63.74-94.73%) during non-typhoon seasons, but typhoons disrupted its nutrient pollutant reduction performance. The proportion of microorganisms involved in nitrogen and phosphorus removal decreased by changes of salinity in typhoon events. Antibiotic resistance genes relative abundances were enriched due to typhoon disaster. The majority antibiotic resistance genes in the system were associated with beta-lactam resistance (4.37 × 104-8.73 × 104). Rare bacterial taxa showed the strongest tolerance in all taxa to typhoon conditions. Archaeal community compositions were sensitive to these disturbances. Disperal limitation and heterogeneous selection were key drivers in bacterial and archaeal community assemblies. Microorganisms and antibiotic resistance genes often co-occurred in non-typhoon seasons. Vibrio was identified as a key potential host of antibiotic resistance genes in both seasons. This study highlights the disruptive effect of typhoons on the stability of MTW treatment systems.