Metabolic Strategies and Resource Preferences in Microbial Communities in Boom-and-Bust Environments

Abstract

Microbial communities assemble and thrive in strongly fluctuating boom-and-bust environments by adopting distinct metabolic strategies to consume resources. While much attention has been given to understanding these strategies in isolated species, their ecological implications in complex communities remain poorly understood. Here, we combine theoretical and computational frameworks to investigate the assembly and ecological properties of microbial communities with diauxic (sequential) and co-utilization strategies.
We show that diauxic microbial communities, where species sequentially utilize resources, spontaneously develop complementary resource preferences during assembly. This complementarity arises because sequential utilization disproportionately relies on the top-choice resource for growth, leading to intuitive ecological partitioning. A geometric approach to analyzing these serially diluted communities further explains emergent patterns, such as the absence of species preferring suboptimal resources for growth.
Comparing sequential and co-utilization strategies, we find that sequential utilizers dominate in species-rich, high-competition communities, leveraging their resilience to fluctuating resource ratios. Their ecological advantage lies in growth rate distributions characterized by wider upper tails, despite lower averages, enabling efficient niche packing and structural stability. Conversely, co-utilizers thrive in low-diversity communities, benefiting from consistently higher average growth rates.
Our work provides a unified explanation for the coexistence of sequential and co-utilizing strategies in natural ecosystems and predicts patterns of community assembly shaped by metabolic strategies. These findings offer testable hypotheses for understanding the dynamics of microbial communities in natural and synthetic environments.