有机解磷菌对天鹅湖潟湖沉积物中磷释放的影响

Effects of organic phosphate-solubilizing bacteria on phosphorus release from sediments in Swan Lagoon

为探讨天鹅湖中有机解磷菌(OPB)的优势种属以及解磷菌对潟湖沉积物磷释放的影响,通过平板培养和16S rDNA序列分析对沉积物中OPB进行筛选鉴定,选取3株代表性菌株(Geobacillus stearothermophilus、Bacillus flexus、Bacillus altitudinis)在沉积物灭菌和非灭菌条件下进行模拟试验,探究OPB接种对上覆水总磷(TP)及沉积物碱性磷酸酶活性(APA)、磷赋存形态的影响。结果表明:芽孢杆菌属(Bacillus sp.)是天鹅湖冬季沉积物中OPB的优势属。沉积物是否灭菌对上覆水TP浓度影响显著,表现为灭菌组的3个接种处理的TP浓度均显著高于非灭菌组。OPB接种促进了天鹅湖沉积物中磷的释放,试验期间灭菌组各处理水体TP浓度变幅为0.049~0.335 mg·L^(-1),其中弯曲芽孢杆菌(Bacillus flexus)和短小芽孢杆菌(Bacillus altitudinis)增幅较大。在试验结束时,大多数处理沉积物中APA和弱吸附态磷(NH4Cl-P)含量明显增加,而可还原态磷(BD-P)和铁铝结合态磷(NaOH-P)含量则有所降低。研究表明,在天鹅湖潟湖沉积物中分布着大量OPB,其可通过分泌碱性磷酸酶或改变氧化还原环境等影响沉积物磷的形态转化及释放潜力,OPB对沉积物内源磷释放的贡献不容忽视。

To identify the dominant organic phosphate-solubilizing bacteria(OPB)species in Swan Lagoon sediments,the technology of plate culture and 16S rDNA sequence analysis was used.Thereafter,three representative strains(Geobacillus stearothermophilus,Bacillus flexus,and Bacillus altitudinis)were selected for the simulation experiment investigating the influence of OPB inoculation on water total phosphorus(TP)concentration,alkaline phosphatase activity(APA),and P fractions in sediments.The experiment included two groups of sterilized and non-sterilized sediments.The results showed that Bacillus was the dominant OPB genus in the sediments of Swan Lagoon in the winter.The sterilization of sediments had a significant effect on the concentration of TP in water and TP concentrations at three inoculation treatments of the sterilized group were significantly higher than that of the non-sterilized group.The OPB inoculation promoted P release from the sediments in Swan Lagoon.TP concentration for different treatments of the sterilized group ranged between 0.049–0.335 mg·L^(-1) and increased markedly for the B.flexus and B.altitudinis treatments.APA and loosely adsorbed P(NH4Cl-P)concentrations in sediments increased for most treatments while the concentrations of redox sensitive P(BD-P)and Fe/Al bound P(NaOH-P)decreased.This study indicates that there are large quantities of OPB in the sediments of Swan Lagoon that affect the transformation and release of sediment P by excreting alkaline phosphatase or changing the redox condition.Therefore,the contribution of OPB to sediment P release cannot be ignored in Swan Lagoon.