氧环境改变对陆基循环水养殖鱼粪碳、氮、磷释放特征及细菌群落的影响

Oxygen environment changes on carbon,nitrogen,and phosphorus release and bacterial community of land-based recirculating aquaculture fish manure

为探究氧环境改变对陆基循环水养殖系统(RAS)中鲈鱼粪氮(N)、磷(P)、溶解性有机质(DOM)释放特征及鱼粪细菌群落多样性的影响,采用室内模拟的方法,分析氧环境(好氧、厌氧)改变对鱼粪及其上覆水理化性质及鱼粪细菌群落特征的影响,并揭示其间的相关关系。结果表明,第1~16天,厌氧处理上覆水中NH_(4)^(+)-N、TP、COD和TOC质量浓度明显高于好氧处理,在第16~33天,NH_(4)^(+)-N质量浓度持续增加、TP质量浓度低于好氧处理组、COD和TOC质量浓度降低但仍高于好氧处理。三维荧光光谱表明,氧环境改变下上覆水DOM主要成分是蛋白质、腐殖质类物质,但厌氧条件下各组分含量均较高。细菌群落分析表明,不同处理鱼粪细菌群落相对丰度存在差异,优势菌门为Proteobacteria、Firmicutes、Actinobacteria、Bacteroidetes、Chloroflexi,相对丰度均大于5%;厌氧处理组优势菌属为Acinetobacter、Clostridium_sensu_stricto_13、Propioniciclava、Ornithinibacter,好氧处理组优势菌属为Acinetobacte、Kurthia、Comamonas、Propioniciclava。细菌群落聚类特征与环境因子相关性表明,随反应时间增加,氧环境改变下细菌群落结构趋于相似;厌氧处理下DOM(C1、C2、C4)、反应时间、COD、TOC、鱼粪TN、鱼粪TP、NO_(3)^(−)-N是影响细菌属的关键环境因子,好氧处理下仅有部分细菌属与反应时间、EC、DOM(C1、C2、C4)、NH_(4)^(+)-N具有显著相关性(P<0.05)。厌氧处理能够显著影响鱼粪及上覆水的理化性质,促进氮、磷及有机质释放,并在一定程度上影响细菌群落结构和多样性,其次是好氧处理。

In order to explore the effects of oxygen environment changes on the release characteristics of nitrogen(N),phosphorus(P),dissolved organic matter(DOM)and bacterial community diversity from fish manure in the land-based circulating water culture system(RAS).The indoor simulation experiments were conducted to analyze the effects of oxygen environment(aerobic and anaerobic)changes on the physicochemical properties of the fish manure and its overlying water,and the bacterial community characteristics of the fish manure,finally reveal their correlations.The results showed that the mass concentrations of NH_(4)^(+)-N,TP,COD,and TOC in the overlying water by anaerobic treatments were significantly higher than that by aerobic treatments at 1-16 d.At 16-33 d,the NH_(4)^(+)-N continuously increased and the TP was lower than that by aerobic treatments.The mass concentrations of COD and TOC by the anaerobic treatment were still higher than that by aerobic treatments.Three-dimensional fluorescence spectroscopy showed that DOM components in the overlying water mainly included protein and humic substances under the changes of oxygen environment,but anaerobic conditions caused higher contents of each component.Microbiological analysis showed that there were differences in the relative abundance of bacterial communities by different treatments.The dominant bacterial phyla were Proteobacteria,Firmicutes,Actinobacteria,Bacteroidetes,and Chloroflexi,and their relative abundances were all greater than 5%.The dominant bacterial genera by anaerobic treatments mainly included Acinetobacter,Clostridium_sensu_stricto_13,Propioniciclava,and Ornithinibacte.The dominant bacterial genera by aerobic treatments were Acinetobacte,Kurthia,Comamonas,and Propioniciclava.The correlation analysis between the clustering characteristics of bacterial community and environmental factors showed that the bacterial community structure by aerobic and anaerobic treatments tended to be similar with the increase of reaction times.The DOM components(C1,C2,and C4),reaction times,COD,TOC,fish manure TN,fish manure TP,and NO_(3)^(−)-N were the key environmental factors that affecting the bacterial genera by anaerobic treatments.There were significant correlations between some bacterial genera and reaction times,EC,DOM(C1,C2,C4),NH_(4)^(+)-N,and COD by aerobic treatments(P<0.05).Additionally,the change in oxygen environment significantly impacted the physicochemical properties of fish manure and its overlying water,promoted the release of N,P and DOM,and influenced on the structure and diversity of bacterial community.These effects by anaerobic treatments were stronger than that by aerobic treatments.