渤海沉积物中微生物铁还原能力及其影响因素探讨

采用恒温厌氧培养实验,以Fe（OH）3为唯一电子受体,通过测定接种不同沉积物提取液后的体系中Fe（Ⅱ）含量变化,研究了渤海沉积物在不同的碳源、温度、厌氧培养时间及pH条件下的铁还原特征。结果表明,从不同水质海区沉积物提取的微生物群落均可以葡萄糖和丙酮酸盐为优势碳源,并迅速还原Fe（Ⅲ）,其利用不同碳源的铁还原能力表现为葡萄糖〉丙酮酸盐〉乳酸盐〉乙酸盐;在不同水质海区之间Fe（Ⅲ）还原程度存在一定差异,Ⅲ类和Ⅳ类水质区域的微生物Fe（Ⅲ）还原能力明显低于Ⅰ类和Ⅱ类水质区域;以葡萄糖和丙酮酸盐作为碳源培养时,在15℃和30℃培养条件下其Fe（Ⅲ）还原反应的活性随着温度的升高而升高,表明微生物在优势碳源下,提高培养温度可促进铁还原反应的效率;淹水时间延长可改变微生物群落结构,促进利用葡萄糖和丙酮酸盐的微生物恢复增长,使Fe（Ⅲ）还原能力增强;微生物群落在pH中性体系条件下Fe（Ⅲ）还原能力最强,随着体系pH值由8.0升高到11.0或pH由6.0降低到3.0,体系中Fe（Ⅲ）还原能力均逐渐降低。

The Capability and Influencing Factors of Microbial Iron Reduction in Marine Sediments from Bohai Bay, China

Anaerobic incubations of leaching liquors from sediments of 4 sites with different water grades in Bohai bay were conducted to research the capability of microbial Fe（Ⅲ） reduction. Influence of carbon sources, temperature, incubation time and pH value on microbial Fe （Ⅲ） reduction was also investigated by monitoring the content of Fe（Ⅱ） in this amended incubation. As results represented, glucose and pyruvate were in prior and quick utility in microbial Fe（Ⅲ） reduction in all the incubations. The capability of microbial Fe（Ⅲ） reduction amended with carbon resource showed in order as glucosepyruvatelactateacetate. Water grades did apparently influence on capability of microbial Fe（Ⅲ） reduction, reflecting by obviously higher capability of water grade of I and Ⅱ than that of Ⅲ and Ⅳ. Temperature from 15 ℃ mote the efficiency of Fe（Ⅲ） reduction with priority carbon sources. Flooding time elongation benefited promoted the microbial community which preferred to utilize glucose and acetate and therefore enhanced the capability of microbial Fe（Ⅲ） reduction. The strongest capability of Fe（Ⅲ） reduction appeared in pH neutral system and the increase of pH value from 8.0 to 11.0 and the decrease from 6.0 to 3.0 both impaired the reduction of Fe（Ⅲ） during incubation.