Available energy fluxes drive a transition in the diversity, stability, and functional structure of microbial communities

TL;DR

This study uses a generalized consumer resource model to show how available energy fluxes cause a transition in microbial communities from energy-limited to diversity-driven regimes, affecting their structure and stability.

Contribution

It introduces a comprehensive model incorporating cross-feeding, stochastic colonization, and thermodynamics to explain microbial community transitions based on energy fluxes.

Findings

Community structure shifts with energy availability

Distinct species abundance and functional profiles in different regimes

Model reproduces observed ecological patterns like nestedness

Abstract

A fundamental goal of microbial ecology is to understand what determines the diversity, stability, and structure of microbial ecosystems. The microbial context poses special conceptual challenges because of the strong mutual influences between the microbes and their chemical environment through the consumption and production of metabolites. By analyzing a generalized consumer resource model that explicitly includes cross-feeding, stochastic colonization, and thermodynamics, we show that complex microbial communities generically exhibit a transition as a function of available energy fluxes from a "resource-limited" regime where community structure and stability is shaped by energetic and metabolic considerations to a diverse regime where the dominant force shaping microbial communities is the overlap between species' consumption preferences. These two regimes have distinct species abundance patterns, different functional profiles, and respond differently to environmental perturbations. Our model reproduces large-scale ecological patterns observed across multiple experimental settings such as nestedness and differential beta diversity patterns along energy gradients. We discuss the experimental implications of our results and possible connections with disorder-induced phase transitions in statistical physics.