DeepEarthshape: Geomicrobiology"Iron-metabolizing bacteria as a driving force in weathering of silicate minerals"

几十年来的研究已经阐明，微生物在地质环境中作为风化剂发挥着至关重要的作用，部分原因是它们能够催化矿物中所含金属的氧化还原转化。以前关于这一过程的大部分工作都集中在游离Fe 2+的微生物氧化或铁氧化物的还原，或Fe（III）还原细菌对粘土矿物的影响。虽然这些都是风化过程的重要方面，但这些矿物本身也是风化产物。铁代谢细菌也可以广泛地促进土壤母质的早期形成，但这在多大程度上是可能的是不确定的。此外，这些细菌相对于土壤发育阶段的分布，丰度和身份（因此可用铁源的性质）几乎完全未知，特别是在微生物铁循环的氧化方面。这种缺乏生态理解的结果，铁代谢细菌往往有低丰度的整体微生物群落，尽管它们的重要生物地球化学的影响。铁代谢过程对土壤发育的潜在巨大影响的确定需要针对这些特定微生物的敏感分子和培养为基础的方法的有针对性的组合。然而，许多这些生物的培养，只能用专门的techniques.We假设，铁代谢细菌群落将共同进化的地质环境在土壤发育过程中，他们的活动，反过来，将提高土壤发育的速度。我们还建议，铁循环社区成员的身份和生理将受到强烈的气候影响，因此他们对土壤形成的贡献将不同的功能。因此，我们建议使用智利沿海山脉的巨大气候梯度，以确定铁代谢细菌的丰度，分布和身份之间的相关性与整个风化剖面（从地表到基岩）的铁源的性质在四个不同的气候制度。然后，我们将利用微观实验来量化这些细菌对铁硅酸盐矿物风化速率和矿物转化的影响。最终，我们的目标是展示这些专门的细菌如何塑造地球表面。

Decades of previous research have elucidated that microorganisms play a crucial role as weathering agents in geological environments, in part due to their ability to catalyse redox transformations of metals contained within minerals. Much of the previous work on this process has focused on the microbial oxidation of free Fe2+ or reduction of iron oxides, or the effect of Fe(III)-reducing bacteria on clay minerals. Whilst these are important aspects of the weathering process, these minerals are themselves weathering products. Fe-metabolizing bacteria could also contribute extensively to early formation of soil parent material, but the extent to which this is possible is undetermined. Furthermore, the distribution, abundance and identity of these bacteria relative to the stage of soil development (thus nature of the available iron source) is almost completely unknown, especially on the oxidative side of the microbial iron cycle. Much of this lack of ecological understanding results from the fact that Fe-metabolizing bacteria often have low abundance in the overall microbial community despite their important biogeochemical impact. Determination of the potentially large impact of Fe-metabolizing processes on soil development requires a targeted combination of sensitive molecular- and cultivation-based approaches towards these specific microorganisms. Cultivation of many of these organisms, however, can only be done with specialist techniques.We hypothesize that the Fe-metabolizing bacterial community will co-evolve with the geological environment during soil development, and that their activity, in turn, will enhance the rate of soil development. We also suggest that the identity and physiology of the Fe-cycling community members will be strongly influenced by climate, thus their contribution to soil formation will differ as a function of this. Therefore, we propose to use the dramatic climate gradient of the Chilean coastal cordillera to determine the correlation between the abundance, distribution and identity of Fe-metabolizing bacteria with the nature of the iron source throughout the weathering profile (from surface to bedrock) under four different climate regimes. We will then utilize microcosm experiments to quantify the effect of these bacteria on weathering rates of Fe-silicate minerals and mineral transformation. Ultimately, we aim to demonstrate how these specialized bacteria act to shape the Earth’s surface.