Nonequilibrium microbial dynamics unveil a new macroecological pattern beyond Taylor's law

Area of Science:

• Microbial Ecology
• Theoretical Ecology
• Statistical Physics

Background:

• Microbial dynamics are influenced by both biotic (species interactions) and abiotic (environmental) factors.
• Observed correlations in natural microbiomes suggest they operate out of thermodynamic equilibrium.
• Taylor's law describes a relationship between species abundance and variance but may be an incomplete approximation.

Purpose of the Study:

• To develop a theoretical framework for analyzing microbial community dynamics under non-equilibrium conditions.
• To investigate the underlying mechanisms generating macroecological patterns, including Taylor's law.
• To identify novel patterns in microbial community structure using existing metagenomic data.

Main Methods:

• Utilized Fokker-Planck formalism to model microbial population dynamics.
• Developed an approximate analytical solution for non-equilibrium dynamics.
• Analyzed existing metagenomic datasets to identify macroecological patterns.

Main Results:

• Demonstrated that equilibrium conditions lead to uncorrelated species abundances, contrasting with real microbiomes.
• The proposed non-equilibrium solution is consistent with Taylor's law but predicts additional, unobserved structure.
• Revealed a novel, universal macroecological pattern in metagenomic data, extending beyond Taylor's law.

Conclusions:

• Microbial communities are inherently out of equilibrium, necessitating non-equilibrium theoretical approaches.
• Taylor's law may emerge from a fluctuation-growth relation, analogous to Brownian motion and resource equipartition.
• The findings uncover new insights into the physical basis of macroecological patterns in microbial systems.