Gallardo-Navarro Oscar, Arbel-Goren Rinat, August Elias, Olmedo-Alvarez Gabriela, Stavans Joel
Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel.
Department of Engineering, Reykjavik University, Reykjavik, Iceland.
Nat Commun. 2025 Jan 22;16(1):950. doi: 10.1038/s41467-025-56244-8.
Active matter, from motile bacteria to animals, can exhibit striking collective and coherent behavior. Despite significant advances in understanding the behavior of homogeneous systems, little is known about the self-organization and dynamics of heterogeneous active matter, such as complex and diverse bacterial communities. Under oxygen gradients, many bacterial species swim towards air-liquid interfaces in auto-organized, directional bioconvective flows, whose spatial scales exceed the cell size by orders of magnitude. Here we show that multispecies bacterial suspensions undergoing oxytactic-driven bioconvection exhibit dynamically driven spatial segregation, despite the enhanced mixing of bioconvective flows, and the fact that these species coexist in their natural habitat. Segregation is observed as patterns of spatially interlocked domains, with local dominance of one of the constituent species in the suspension. Our findings suggest that segregation mechanisms are driven by species-specific motile behaviors under conditions of hydrodynamic flow, rather than biochemical repulsion. Thus, species with different motile characteristics in the same ecological context can enhance their access to limiting resources. This work provides novel insights on the role of heterogeneity in active matter, as well as on the dynamics of complex microbial communities, their spatial organization and their collective behavior.
从游动细菌到动物，活性物质都能展现出引人注目的集体和连贯行为。尽管在理解均匀系统行为方面取得了重大进展，但对于异质活性物质（如复杂多样的细菌群落）的自组织和动力学却知之甚少。在氧气梯度下，许多细菌物种会以自组织的定向生物对流形式游向气液界面，其空间尺度比细胞大小超出几个数量级。在此我们表明，经历趋氧驱动生物对流的多物种细菌悬浮液，尽管生物对流增强了混合，且这些物种在其自然栖息地中共存，但仍表现出动态驱动的空间分离。分离表现为空间上相互锁定的区域模式，悬浮液中一种组成物种在局部占主导地位。我们的研究结果表明，分离机制是由流体动力流下物种特异性的运动行为驱动的，而非生化排斥。因此，在相同生态环境中具有不同运动特征的物种可以增加它们获取有限资源的机会。这项工作为异质性在活性物质中的作用，以及复杂微生物群落的动力学、其空间组织和集体行为提供了新的见解。
