Stranghoener Marius, Schippers Axel, Dultz Stefan, Behrens Harald
Institute of Mineralogy, Leibniz Universität Hannover, Hanover, Germany.
Geomicrobiology, Federal Institute for Geosciences and Natural Resources, Hanover, Germany.
Front Microbiol. 2018 Jun 14;9:1252. doi: 10.3389/fmicb.2018.01252. eCollection 2018.
The interaction of a single bacterial species () with basaltic rocks from the ICDP HSDP2 drill core and synthetic basaltic glasses was investigated in batch laboratory experiments to better understand the role of microbial activity on rock alteration and Fe mobilization. Incubation experiments were performed with drill core basaltic rock samples to investigate differences in the solution chemistry during biotic and abiotic alteration. Additionally, colonization experiments with synthetic basaltic glasses of different Fe redox states and residual stresses were performed to evaluate their influence on microbial activity and surface attachment of cells. In biotic incubation experiments bacterial growth was observed and the release of Fe and other major elements from drill core basaltic rocks to solution exceeded that of abiotic controls only when the rock sample assay was nutrient depleted. The concentration of dissolved major elements in solution in biotic colonization experiments with synthetic basaltic glasses increased with increasing residual stress and Fe(II) content. Furthermore, the concentration of dissolved Fe and Al increased similarly in biotic colonization experiments indicating that their dissolution might be triggered by microbial activity. Surface morphology imaging by SEM revealed that cells on basaltic rocks in incubation experiments were most abundant on the glass and surfaces with high roughness and almost absent on minerals. In colonization experiments, basaltic glasses with residual stress and high Fe(II) content were intensely covered with a cellular biofilm. In contrast, glasses with high Fe(III) content and no residual stress were sparsely colonized. We therefore conclude that structurally bound Fe is most probably used by as a nutrient. Furthermore, we assume that microbial activity overall increased rock dissolution as soon as the environment becomes nutrient depleted. Our results show that besides compositional effects, other factors such as redox state and residual stress can control microbial alteration of basaltic glasses.
通过批量实验室实验，研究了单一细菌物种（）与国际大陆钻探计划（ICDP）热结构钻探计划2（HSDP2）钻孔岩芯的玄武岩以及合成玄武玻璃之间的相互作用，以更好地了解微生物活动在岩石蚀变和铁迁移中的作用。对钻孔岩芯玄武岩样品进行了培养实验，以研究生物蚀变和非生物蚀变过程中溶液化学的差异。此外，还对具有不同铁氧化还原状态和残余应力的合成玄武玻璃进行了定殖实验，以评估它们对微生物活动和细胞表面附着的影响。在生物培养实验中观察到细菌生长，并且只有当岩石样品分析显示营养耗尽时，钻孔岩芯玄武岩中铁和其他主要元素向溶液中的释放量才超过非生物对照。在使用合成玄武玻璃的生物定殖实验中，溶液中溶解的主要元素浓度随着残余应力和Fe（II）含量的增加而增加。此外，在生物定殖实验中，溶解的铁和铝的浓度也有类似的增加，这表明它们的溶解可能是由微生物活动引发的。扫描电子显微镜（SEM）的表面形态成像显示，在培养实验中，玄武岩上的细胞在玻璃和高粗糙度表面上最为丰富，而在矿物表面上几乎不存在。在定殖实验中，具有残余应力和高Fe（II）含量的玄武玻璃被细胞生物膜密集覆盖。相比之下，具有高Fe（III）含量且无残余应力的玻璃定殖较少。因此，我们得出结论，结构结合的铁很可能被用作营养物质。此外，我们假设一旦环境变得营养耗尽，微生物活动总体上会增加岩石溶解。我们的结果表明，除了成分影响外，其他因素如氧化还原状态和残余应力也可以控制玄武玻璃的微生物蚀变。
