Scale free density and correlations fluctuations in the dynamics of large microbial ecosystems

TL;DR

This paper investigates the complex, scale-free fluctuations and correlations in large microbial ecosystems, proposing criticality as a key mechanism for their robustness and irregular dynamics.

Contribution

It provides evidence of scale-free density fluctuations, correlations, and avalanching dynamics in microbial communities, linking these to criticality.

Findings

Scale-free density fluctuations observed across communities

Anomalous variance scaling identified

Stationary scale-free avalanching dynamics detected

Abstract

Microorganisms self-organize in very large communities exhibiting complex fluctuations. Despite recent advances, still the mechanism by which these systems are able to exhibit large variability at the one hand and dynamical robustness on the other, is not fully explained. With that motivation, here we analyze three aspects of the dynamics of the microbiota and plankton: the density fluctuations, the correlation structure and the avalanching dynamics. In all communities under study we find that the results exhibits scale-free density fluctuations, anomalous variance' scaling, scale-free abundance correlations and stationary scale-free avalanching dynamics. These behaviors, typical in systems exhibiting critical dynamics, suggest criticality as a potential mechanism to explain both the robustness and (paradoxical) high irregularity of processes observed in very large microbial communities.