Non-equilibrium microbial dynamics unveil a new macroecological pattern beyond Taylor's law

TL;DR

This paper develops a non-equilibrium theoretical framework using Fokker-Planck formalism to explain microbial community dynamics, revealing a new macroecological pattern beyond Taylor's law and analyzing real data to support this.

Contribution

It introduces a novel non-equilibrium model for microbial dynamics that predicts new macroecological patterns beyond existing laws, supported by data analysis.

Findings

Equilibrium microbiomes show no species abundance correlations.

Non-equilibrium dynamics predict structures beyond Taylor's law.

Analysis of metagenomic data reveals a universal macroecological pattern.

Abstract

We introduce a comprehensive analytical benchmark, relying on Fokker-Planck formalism, to study microbial dynamics in presence of both biotic and abiotic forces. In equilibrium, we observe a balance between the two kinds of forces, leading to no correlations between species abundances. This implies that real microbiomes, where correlations have been observed, operate out of equilibrium. Therefore, we analyze non-equilibrium dynamics, presenting an ansatz for an approximate solution that embodies the complex interplay of forces in the system. This solution is consistent with Taylor's law as a coarse-grained approximation of the relation between species abundance and variance, but implies subtler effects, predicting unobserved structure beyond Taylor's law. Motivated by this theoretical prediction, we refine the analysis of existing metagenomic data, unveiling a novel universal macroecological pattern. Finally, we speculate on the physical origin of Taylor's law: building upon an analogy with Brownian motion theory, we propose that Taylor's law emerges as a Fluctuation-Growth relation resulting from equipartition of environmental resources among microbial species.