Biological Low-pH Mn(II) Oxidation in a Manganese Deposit Influenced by Metal-Rich Groundwater
Biological Low-pH Mn(II) Oxidation in a Manganese Deposit Influenced by Metal-Rich Groundwater
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DOI：
10.1128/aem.03844-15
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发表时间：
2016-05-01
影响因子：
4.4
通讯作者：
Kuesel, Kirsten
中科院分区：
文献类型：
--
作者：
Bohu, Tsing;Akob, Denise M.;Kuesel, Kirsten
生物低pH值Mn（II）氧化的机制，关键生物和地球化学意义在很大程度上是未探索的。在这里，我们调查了土著锰（II）-氧化微生物群落的结构在二级地下锰氧化物存款的影响，酸性（pH 4.8）富含金属的地下水在前铀矿区。微生物多样性是最高的锰存款相比，相邻的土壤层，包括大多数已知的锰（II）-氧化细菌（MOB）和两个属的已知锰（II）-氧化真菌（MOF）。电子X射线微区分析表明，该存款中明显富集有菱锰矿[（Ba，H2O）（2）（Mn 4+，Mn 3+）（5）O-10]。典型对应分析表明，某些真菌，细菌和古菌群与本地锰氧化物密切相关。在pH 5.5或7.2的酸性锰存款中分离出变形菌门、放线菌门和拟杆菌门内的8种MOB和属于子囊菌门的1种MOF菌株。土壤-地下水缩影表明，锰存款中锰（II）的消耗速度比邻近土壤层快2.5倍。在非生物对照中未观察到耗竭，表明生物贡献是低pH值下Mn（II）氧化的主要驱动力。天然低pH值Mn（II）氧化剂的组成和物种特异性高度适应原位条件，这些生物可能在基本的生物地球化学过程中发挥核心作用（例如：例如，在一个实施例中，金属自然衰减）发生在酸性，贫营养，和含金属的底土生态系统。重要性这项研究提供了多条证据表明，即使在酸性pH值下，微生物是Mn（II）氧化的主要驱动因素，为Mn的地球化学循环提供了新的见解。一个独特的、高度适应的微生物群落栖息在酸性、贫营养的锰矿床中，并介导生物锰氧化。这些数据突出了生物过程的重要性，锰生物化学循环，并显示了新的生物修复策略，旨在提高生物锰氧化在低pH值环境中的污染物缓解的潜力。
The mechanisms, key organisms, and geochemical significance of biological low-pH Mn(II) oxidation are largely unexplored. Here, we investigated the structure of indigenous Mn(II)-oxidizing microbial communities in a secondary subsurface Mn oxide deposit influenced by acidic (pH 4.8) metal-rich groundwater in a former uranium mining area. Microbial diversity was highest in the Mn deposit compared to the adjacent soil layers and included the majority of known Mn(II)-oxidizing bacteria (MOB) and two genera of known Mn(II)-oxidizing fungi (MOF). Electron X-ray microanalysis showed that romanechite [(Ba, H2O)(2)(Mn4+, Mn3+)(5)O-10] was conspicuously enriched in the deposit. Canonical correspondence analysis revealed that certain fungal, bacterial, and archaeal groups were firmly associated with the autochthonous Mn oxides. Eight MOB within the Proteobacteria, Actinobacteria, and Bacteroidetes and one MOF strain belonging to Ascomycota were isolated at pH 5.5 or 7.2 from the acidic Mn deposit. Soil-groundwater microcosms demonstrated 2.5-fold-faster Mn(II) depletion in the Mn deposit than adjacent soil layers. No depletion was observed in the abiotic controls, suggesting that biological contribution is the main driver for Mn(II) oxidation at low pH. The composition and species specificity of the native low-pH Mn(II) oxidizers were highly adapted to in situ conditions, and these organisms may play a central role in the fundamental biogeochemical processes (e. g., metal natural attenuation) occurring in the acidic, oligotrophic, and metalliferous subsoil ecosystems.IMPORTANCEThis study provides multiple lines of evidence to show that microbes are the main drivers of Mn(II) oxidation even at acidic pH, offering new insights into Mn biogeochemical cycling. A distinct, highly adapted microbial community inhabits acidic, oligotrophic Mn deposits and mediates biological Mn oxidation. These data highlight the importance of biological processes for Mn biogeochemical cycling and show the potential for new bioremediation strategies aimed at enhancing biological Mn oxidation in low-pH environments for contaminant mitigation.