• 关键词：电缆细菌  南沙河沉积物  活性磷  活性铁  活性硫  薄膜扩散梯度 （DGT） 技术

• 基金项目：国家自然科学基金重大培育项目（No.2017YFA0605003）

• 张靖天
• 中国环境科学研究院，环境基准与风险评估国家重点实验室，北京 100012

• 卢艳敏
• 中国环境科学研究院，环境基准与风险评估国家重点实验室，北京 100012;北京中联环工程股份有限公司，北京 100044

• 霍守亮
• 中国环境科学研究院，环境基准与风险评估国家重点实验室，北京 100012

• 马春子
• 中国环境科学研究院，环境基准与风险评估国家重点实验室，北京 100012

• 许晓玲
• 中国环境科学研究院，环境基准与风险评估国家重点实验室，北京 100012

• 摘要：电缆细菌的存在会改变沉积物-水界面的氧化还原环境，进而影响沉积物-水系统中磷、铁、硫的迁移转化过程.本研究选取存在电缆细菌的原位南沙河沉积物-水系统为研究对象，在暗处15 ℃下培养30 d，利用薄膜扩散梯度（DGT）技术获取了活性磷、活性硫和活性铁的2 mm 分辨率剖面分布特征，并结合原位荧光杂交技术确定了电缆细菌的密度.结果表明：随着沉积深度的增加，间隙水活性磷、活性铁和活性硫均呈现出先增加后减小再趋于稳定的趋势，均值分别为0.743~1.017 mg·L^-1、0.383~0.954 mg·L^-1和0.033~0.141 mg·L^-1，且均有向上覆水释放的 趋势.随着培养时间的延长，0~1 cm间隙水中活性磷含量呈先减小后增加的趋势，在第10 d达到最小，均值为0.604 mg·L^-1，1 cm以下间隙水中活性磷含量呈现逐渐增加的趋势，在第30 d达到最大，均值为1.090 mg·L^-1.0~10 cm间隙水中活性铁和活性硫含量呈现先增加后减小的趋势，在第10 d达到最大，均值分别为0.954 mg·L^-1和0.141 mg·L^-1.电缆细菌主要生活在0~3 cm沉积物层，其密度随培养时间延长呈先增大后减小的趋势，以第10 d时0~1 cm沉积物层密度最大，为24.716 m·cm^-3.Pearson相关性分析表明：0~3 cm沉积物中电缆细菌与活性铁呈显著正相关，相关系数为0.674；活性铁与活性硫呈显著正相关，相关系数为0.615，活性磷与活性铁、活性硫和电缆细菌呈负相关.表层0~3 cm沉积物中 电缆细菌的生长对FeS的利用有助于同层活性铁含量增加的同时，也促进了活性硫在间隙水中的溶解.电缆细菌对硫化亚铁和硫化氢的氧化作用在沉积物-水界面形成铁氧保护层改变了体系中氧化还原环境，影响了间隙水中磷、铁、硫的分布.

• Abstract：The activity of cable bacteria can greatly change the redox environment of sediment and subsequently affected the migration and transformation of phosphorus， iron and sulfur at sediment-water interface. In the present study， the sediment-water interface systems constructed by the in situ sediment cores and overlying water from a cable bacteria habitat （South Shahe， Beijing） were incubated at 15 ℃ for 30 days under dark conditions. The distribution profiles of phosphorus， iron and sulfur in pore water were investigated by diffusive gradients in thin-films （DGT） technique at 2 mm-resolution， and the density of cable bacteria in sediment was determined by fluorescence in situ hybridization（FISH）， simultaneously. Our results revealed the similar depth profiles of the reactive phosphorus， reactive sulfur， and reactive iron in pore water， the concentration of them initially increased with depth， then decreased and finally stabilized at deeper sediment， all the three elements showed a tendency to release to the overlying water. The mean concentrations of the reactive phosphorus， reactive sulfur， and reactive iron in pore water were within the range of 0.743~1.017， 0.383~0.954 and 0.033~0.141 mg·L^-1， respectively. During the incubation period， the concentration of reactive phosphorus in pore water of the surface sediment （0~1 cm） first decreased until reaching the minimum value at day 10 with mean concentration of 0.604 mg·L^-1， and then increased at the rest of incubation， while the concentration of which in the pore water of deeper sediment （1~10 cm） increased with incubation time and reached a peak value at day 30 with a mean concentration of 1.090 mg·L^-1. The concentration of reactive iron and sulfur contents in pore water （0~10 cm） first increased with incubation time and decreased afterwards， the maximum values of them were observed at day 10 with a mean concentration of 0.954 mg·L^-1 and 0.141 mg·L^-1， respectively. Cable bacteria was mainly distributed in the surface sediment with a depth of 0~3 cm， their density firstly increased with incubation time and then declined gradually afterwards. The highest density of cable bacteria was observed at day 10 in the top 0~1 cm sediment， with a value of 24.716 m·cm^-3. Pearson correlation analysis demonstrated that the concentration of reactive iron in pore water was significantly and positively correlated with cable bacteria density in the top 0~3 cm sediment （r=0.674）. Similar correlations were also observed between the concentration of reactive iron and reactive sulfur in pore water（r=0.615）. However， the concentration of reactive phosphorus in pore water showed a negative correlation with the corresponding concentration of reactive iron， reactive sulfur and the density of cable bacteria. The growth of cable bacteria resulted in the dissolution of FeS in top 0~3 cm sediments， and facilitated the release of reactive iron and reactive sulfur into pore water. The formation of protective iron oxides layer due to the oxidation of FeS and H₂S by cable bacteria changed the redox conditions at sediment-water interface， and thus influenced the distribution of phosphorus， iron and sulfur in pore water.

• Key words：cable bacteria  South Shahe sediment  reactive phosphorus  reactive iron  reactive sulfur  diffusive gradients in thin-films technique

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