Chemotaxis under flow disorder shapes microbial dispersion in porous media
Chemotaxis under flow disorder shapes microbial dispersion in porous media
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DOI：
10.1038/s41567-020-1002-x
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发表时间：
2020-09-14
期刊：
影响因子：
19.6
通讯作者：
Juanes, Ruben
中科院分区：
文献类型：
--
作者：
de Anna, Pietro;Pahlavan, Amir A.;Juanes, Ruben
细菌生活在异质环境中，因此研究它们在多孔介质中的行为是很重要的。在这里，作者表明，流动紊乱增强了多孔介质中微孔中化学梯度的作用，从而有助于细菌的运输。天然土壤是微生物高密度(1)和多样性(2)的宿主，甚至深土多孔岩石也为活跃的微生物群落提供了栖息地(3)。在这些环境中，微生物的无序流动与广泛的自然和工程过程有关，从生化循环到再矿化和生物修复（4-7）。然而，由于多孔介质的无序流动和相关的化学梯度特征，细菌如何在地下运输和分布仍然知之甚少，部分原因是迄今为止的研究主要集中在稳定的宏观化学梯度上（8-10）。在这里，我们使用一种微流体模型系统来捕获孔隙尺度上的流动紊乱和化学梯度，以量化土壤中的枯草芽孢杆菌在多孔介质中的运输和分散。我们观察到趋化性强烈调节细菌在孔隙空间低流量区域的持久性，导致它们的分散系数增加100%。这种效应直接源于流动紊乱造成的强孔隙尺度梯度，并表明细菌行为和孔隙尺度紊乱之间的微观相互作用可以影响地下生物群的宏观动态。
Bacteria live in heterogeneous environments, so it is important to investigate their behaviour in porous media. Here the authors show that flow disorder enhances the effect of chemical gradients in micropockets in a porous medium, which then aid the transport of bacteria.Natural soils are host to a high density(1)and diversity(2)of microorganisms, and even deep-earth porous rocks provide a habitat for active microbial communities(3). In these environments, microbial transport by disordered flows is relevant for a broad range of natural and engineered processes, from biochemical cycling to remineralization and bioremediation(4-7). Yet, how bacteria are transported and distributed in the subsurface as a result of the disordered flow and the associated chemical gradients characteristic of porous media has remained poorly understood, in part because studies have so far focused on steady, macroscale chemical gradients(8-10). Here, we use a microfluidic model system that captures flow disorder and chemical gradients at the pore scale to quantify the transport and dispersion of the soil-dwelling bacteriumBacillus subtilisin porous media. We observe that chemotaxis strongly modulates the persistence of bacteria in low-flow regions of the pore space, resulting in a 100% increase in their dispersion coefficient. This effect stems directly from the strong pore-scale gradients created by flow disorder and demonstrates that the microscale interplay between bacterial behaviour and pore-scale disorder can impact the macroscale dynamics of biota in the subsurface.