Abstract Microbial biofilms on stainless steel surfaces exposed to water from a freshwater pond were dominated by manganese-oxidizing bacteria, as initially diagnosed by microscopy and elemental analysis. The application of electron paramagnetic resonance (EPR) spectroscopy revealed conspicuous sextet (six-line) patterns that intensified with immersion time, implying the gradual accumulation of Mn(II) in the biofilms. Correspondingly, cathodic polarization designated the manganese oxide (MnOx) reduction peak in the form of a distinctive ‘nose’, which grew increasingly more negative with biofilm growth. The progressive expansion of cathodic current densities and the concurrent area-under-the-curve also allowed the quantification of microbially mediated MnOx deposition. Furthermore, the merger of EPR and cathodic polarization techniques yielded key insights, in tandem with Mn speciation data, into the pathways of microbial manganese transformations in biofilms, besides providing meaningful interpretations of prevailing literature. Accordingly, the natural freshwater biofilm was inferred as one supporting a complete manganese cycle encompassing multiple redox states.

中文翻译：

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通过 EPR 光谱和阴极极化的合并描绘锰生物膜

摘要 接触淡水池塘水的不锈钢表面的微生物生物膜主要是锰氧化细菌，最初通过显微镜和元素分析诊断。电子顺磁共振 (EPR) 光谱的应用揭示了显着的六重奏（六线）图案，随着浸泡时间的推移而加剧，这意味着 Mn（II）在生物膜中逐渐积累。相应地，阴极极化以独特的“鼻子”的形式指定了氧化锰 (MnOx) 还原峰，随着生物膜的生长，它变得越来越负。阴极电流密度的逐渐扩大和同时存在的曲线下面积也允许对微生物介导的 MnOx 沉积进行量化。此外，EPR 和阴极极化技术的结合与锰物种形成数据相结合，产生了对生物膜中微生物锰转化途径的关键见解，此外还提供了对流行文献的有意义的解释。因此，推断天然淡水生物膜支持包含多种氧化还原状态的完整锰循环。