Frequency and amplitude dependent population dynamics during cycles of feast and famine

TL;DR

This study investigates how cyclic nutrient fluctuations influence Escherichia coli population dynamics, revealing that the frequency and amplitude of nutrient changes significantly affect aggregation, dispersal, and overall population behavior.

Contribution

It demonstrates that environmental fluctuation parameters critically shape microbial population dynamics through nutrient-dependent aggregation and dispersal mechanisms.

Findings

Population abundance depends on fluctuation frequency and amplitude.

A phenomenological model accurately predicts observed dynamics.

Environmental fluctuations significantly alter spatial structure and population behavior.

Abstract

In nature microbial populations are subject to fluctuating nutrient levels. Nutrient fluctuations are important for evolutionary and ecological dynamics in microbial communities since they impact growth rates, population sizes and biofilm formation. Here we use automated continuous-culture devices and high-throughput imaging to show that when populations of Escherichia coli are subjected to cycles of nutrient excess (feasts) and scarcity (famine) their abundance dynamics during famines depend on the frequency and amplitude of feasts. We show that frequency and amplitude dependent dynamics in planktonic populations arise from nutrient and history dependent rates of aggregation and dispersal. A phenomenological model recapitulates our experimental observations. Our results show that the statistical properties of environmental fluctuations have substantial impacts on spatial structure in bacterial populations driving large changes in abundance dynamics.