Nutrient transport driven by microbial active carpets

TL;DR

This paper investigates how active bacterial carpets generate flows that enhance nutrient transport, using a comprehensive theory to analyze various patterns and the importance of architectural diversity for biofunctionality.

Contribution

It introduces a full theoretical framework linking active matter density and velocity gradients to nutrient transport in microbial carpets, highlighting the role of architecture diversity.

Findings

Active carpets produce coherent flows towards the substrate.

Flow patterns are tunable via confinement.

Diversity in carpet structure is crucial for maintaining biofunctionality.

Abstract

We demonstrate that active carpets of bacteria or self-propelled colloids generate coherent flows towards the substrate, and propose that these currents provide efficient pathways to replenish nutrients that feed back into activity. A full theory is developed in terms of gradients in the active matter density and velocity, and applied to bacterial turbulence, topological defects and clustering. Currents with complex spatiotemporal patterns are obtained, which are tuneable through confinement. Our findings show that diversity in carpet architecture is essential to maintain biofunctionality.