中国水产科学2025，Vol.32Issue(11)：1616-1627,12.DOI:10.12264/JFSC2025-0120
碳源添加条件下藻-菌互作对养殖水体氨氮转化与细菌群落的调控
Regulation of ammonia nitrogen transformation and bacterial communities in aquaculture water through algae-bacteria interactions with carbon source addition
摘要
Abstract
Biofloc technology(BFT),often enhanced by the addition of external carbon sources to stimulate heterotrophic bacterial ammonia nitrogen assimilation,is essential for sustainable aquaculture.In BFT systems exposed to light,microalgae are also present;however,their role in ammonia nitrogen removal and their influence on bacterial communities remain insufficiently understood.This knowledge gap hinders the comprehensive elucidation and optimization of BFT,potentially affecting system stability and biosecurity.In this study,we aimed to elucidate the specific contributions of microalgae to the transformation of ammonia nitrogen and their regulatory effects on bacterial communities within a carbon-amended aquaculture system.We hypothesized that microalgae play a significant role in direct ammonia assimilation and substantially influence bacterial community structure,diversity,and the prevalence of potential pathogens.A 7-day microcosm experiment was conducted using four treatments:a blank control group with ammonia only(C),a carbon-supplemented control group(GA)with ammonia and glucose and a C-to-N ratio of 6∶1,an algae-removed plus carbon-supplemented group(PF),and a bacteria-inhibited plus carbon-supplemented group(AT).We monitored inorganic nitrogen dynamics,quantified bacterial biomass,and analyzed bacterial community structure using 16S rRNA gene sequencing.Glucose supplementation shifted nitrogen transformation from nitrification,which dominated in the blank control group,toward microbial assimilation,accounting for approximately 84.6％of ammonia removal in the carbon control group.Notably,the bacteria-inhibited group exhibited substantial direct ammonia assimilation by microalgae,as indicated by a 1.65 mg/L decrease in ammonia concentration,representing an estimated 46％ of total ammonia removal in the algae-bacteria co-culture control.These results highlight the active and significant role of microalgae in nitrogen uptake.The removal of microalgae increased bacterial biomass and total ammonia removal to 4.29 mg/L,suggesting reduced competition.However,this was accompanied by ecological drawbacks,as bacterial α-diversity increased,along with an increased relative abundance of potential opportunistic pathogens,such as Chlamydiae and Vogesella.Thus,although bacterial-driven nitrogen removal improved in the absence of microalgae,the microbial community became relatively less stable,and biosecurity risks increased.Conversely,the presence of microalgae in the carbon control group suppressed excessive bacterial proliferation and fostered a relatively more stable bacterial community,dominated by Proteobacteria,particularly the genus Polynucleobacter,with significantly lower abundances of the aforementioned pathogens.These findings suggest that microalgae function both as competitors and key regulators,potentially through nutrient competition,allelopathic effects,or by promoting beneficial bacterial associations,thereby exerting a protective impact on the microbial ecosystem.Our findings provide compelling evidence that microalgae in carbon-amended BFT systems can be used as crucial ecological engineers.Their role extends beyond direct nitrogen assimilation to shaping bacterial community assembly,stability,and functionality.Although direct nutrient competition occurs,the overall effect of a robust microalgal population is a balanced and biosecure microbial ecosystem.This challenges the view that maximizing heterotrophic bacterial activity alone is optimal for BFT.Effective BFT management should prioritize developing a balanced algal-bacterial consortium to optimize nitrogen cycling,enhance system resilience,and reduce pathogenic risks.In conclusion,microalgae in carbon-supplemented aquaculture systems fulfill a dual and critical function,i.e.,they directly assimilate substantial amounts of ammonia and orchestrate bacterial community dynamics to enhance ecological stability and suppress potential pathogens.Recognizing and leveraging these algae-bacteria synergies is essential for the development of relatively more robust,efficient,and environmentally sustainable biofloc technologies.关键词
生物絮团/碳源/藻-菌互作/氮转化/细菌群落Key words
biofloc/carbon source/algae-bacteria interaction/nitrogen transformation/bacterial community分类
农业科技引用本文复制引用
应可佳,何琳,柳敏海,林志华,郑侠飞..碳源添加条件下藻-菌互作对养殖水体氨氮转化与细菌群落的调控[J].中国水产科学,2025,32(11):1616-1627,12.基金项目
浙江省自然科学基金项目(LTGN24C190006) （LTGN24C190006）
宁波市自然科学基金项目(2022J050) （2022J050）
宁波市重点研发计划暨"揭榜挂帅"项目(2023Z113) （2023Z113）
