Microbes in porous environments: From active interactions to emergent feedback

Abstract: Microbes thrive in diverse porous environments -- from soil and riverbeds to human lungs and cancer tissues -- spanning multiple scales and conditions. Short- to long-term fluctuations in local factors induce spatio-temporal heterogeneities, often leading to physiologically stressful settings. How microbes respond and adapt to such biophysical constraints is an active field of research where considerable insight has been gained over the last decade and a half. With a focus on bacteria, here we review recent advances in microbial self-organization and dispersal in inorganic and organic porous settings, highlighting the role of active interactions and feedback which mediate their survival and fitness. We conclude by discussing open questions and opportunities for leveraging integrative cross-disciplinary approaches to advance our understanding of the biophysical strategies that microbes employ -- at both species and community scales -- to make porous settings habitable. Active and responsive behaviour is key to microbial survival in porous environments, with far-reaching ramifications for developing strategies to mitigate anthropogenic impacts, innovate subsurface storage solutions, and predict future ecological scenarios imposed by current climatic changes.