陈鹏程,李晓敏,李芳柏*(1.中国科学院广州地球化学研究所,广东 广州 510640；.广东省生态环境与土壤研究所,广东 广州 510650；3.中国科学院大学,北京 100049)

水稻土Fe(II)氧化耦合NO3-还原的微生物变化

陈鹏程1,2,3,李晓敏2,李芳柏2*(1.中国科学院广州地球化学研究所,广东 广州 510640；2.广东省生态环境与土壤研究所,广东 广州 510650；3.中国科学院大学,北京 100049)

利用不同驯化条件(Soil、Soil+Fe(II)、Soil+NO3-和Soil+Fe(II)+NO3-)对华南水稻土进行中性厌氧条件下的富集培养, 探究淹水期水稻土亚铁(Fe(II))氧化和硝酸盐(NO3-)还原过程,及此过程中微生物群落的变化.结果表明,在 Soil+Fe(II)处理中,亚铁不能发生自然氧化.只有在Soil+Fe(II)+NO3-处理中,Fe(II)才能被氧化成Fe(III);同时,Fe(II)的存在减慢了NO3-的还原.利用高通量测序技术表征微生物群落组成随培养时间的变化,结果表明, Soil+Fe(II)和Soil处理的微生物群落组成没有显著差异.在Soil+NO3-处理中,Pseudogulbenkiania、Flavobacterium和Rhodocyclus属成为优势菌群.在Soil+Fe(II)+NO3-处理中,Zoogloea、Geothrix、Sunxiuqinia和Vulcanibacillus等属成为优势菌群,主要包括硝酸盐还原菌、Fe(II)氧化菌和Fe(III)还原菌.

亚铁氧化；硝酸盐还原；微生物群落；水稻土；中性pH

-and Soil+Fe(II)+NO3-) at circumneutral pH under anoxic conditions. The objectives were to investigate the transformations of Fe(II) and nitrate as well as the shifts of composition and diversity of microbial communities during these processes. The results revealed that Fe(II) could not be oxidized in the treatment of Soil+Fe(II), but only be oxidized in the treatment of Soil+Fe(II)+NO3-. Meanwhile, the presence of Fe(II) slowed down the NO3

-reduction. Illumina high throughput sequencing was used to profile the diversity and abundance of microbial communities over time. The results showed that no significant difference of microbial communities between treatments of Soil+Fe(II) and Soil. Pseudogulbenkiania, Flavobacterium and Rhodocyclus gradually became the dominant genera in the treatment of Soil+NO3

-. Zoogloea, Geothrix, Sunxiuqinia and Vulcanibacillus were the most abundant genera in the treatment of Soil+Fe(II)+NO3-, which was a mixture of nitrate reducers, Fe(II) oxidizers and Fe(III) reducers. Key words：Fe(II) oxidation；nitrate reduction；microbial community；paddy soil；circumneutral pH

铁元素是地壳中含量第 4高的变价金属元素[1].铁的生物地球化学循环过程耦合其他元素的氧化还原过程,对碳、氮和重金属等元素的转化有重要的影响[2-4].铁在天然环境中多数以不溶态 Fe(III)氧化物的形式存在.微生物驱动的Fe(II)氧化和 Fe(III)还原可以发生在厌氧环境中[5].厌氧环境中铁氧化还原过程主要是由铁相关微生物群落所驱动的,包括Fe(II)氧化菌和Fe(III)还原菌[6].其中,硝酸盐依赖型亚铁氧化微生物可以利用厌氧环境中的硝酸……