Particle foraging strategies promote microbial diversity in marine environments

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Abstract

Microbial foraging in patchy environments, where resources are fragmented into particles or pockets embedded in a large matrix, plays a key role in natural environments. In the oceans and freshwater systems, particle-associated bacteria can interact with particle surfaces in different ways: some colonize only during short transients, while others form long-lived, stable colonies. We do not yet understand the ecological mechanisms by which both short-term and long-term colonizers can coexist. Here, we address this problem with a mathematical model that explains how marine populations with different detachment rates from particles can stably coexist. In our model, populations grow only while on particles, but also face the increased risk of mortality by predation and sinking. Key to coexistence is the idea that detachment from particles modulates both net growth and mortality, but in opposite directions, creating a trade-off between them. While slow-detaching populations show the highest growth return (i.e., produce more net offspring), they are more susceptible to suffer higher rates of mortality than fast-detaching populations. Surprisingly, fluctuating environments, manifesting as blooms of particles (favoring growth) and predators (favoring mortality) significantly expand the likelihood that populations with different detachment rates can coexist. Our study shows how the spatial ecology of microbes in the ocean can lead to a predictable diversification of foraging strategies and the coexistence of multiple taxa on a single growth-limiting resource.

Data availability

Data Availability: Ours is a modeling and theoretical study, and has no associated data. All associated computer code relevant for the study and for reproducing the results is available as a GitHub repository at the following link: https://github.com/alieb-mit-edu/Bacterial-dispersal-model.

Article and author information

Author details

Ali Ebrahimi

Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, United States

Competing interests
The authors declare that no competing interests exist.
Akshit Goyal

Department of Physics, Massachusetts Institute of Technology, Cambridge, United States

Competing interests
The authors declare that no competing interests exist.
Otto X Cordero

Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, United States

For correspondence
ottox@mit.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-2695-270X

Funding

Gordon and Betty Moore Foundation (GBMF4513)

Akshit Goyal

Simons Foundation (542395)

Otto X Cordero

Swiss National Science Foundation (P2EZP2 175128)

Ali Ebrahimi

Swiss National Science Foundation (P400PB_186751)

Ali Ebrahimi

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.