Many ways to stay in the game: Individual variability maintains high biodiversity in planktonic microorganisms

Document Type

Article

Date of Original Version

6-6-2014

Abstract

In apparent contradiction to competition theory, the number of known, coexisting plankton species far exceeds their explicable biodiversity - a discrepancy termed the Paradox of the Plankton. We introduce a new game-theoretic model for competing microorganisms in which one player consists of all organisms of one species. The stable points for the population dynamics in our model, known as strategic behaviour distributions (SBDs), are probability distributions of behaviours across all organisms which imply a stable population of the species as awhole.We find that intra-specific variability is the key characteristic that ultimately allows coexistence because the outcomes of competitions between individuals with variable competitive abilities are unpredictable. Our simulations based on the theoretical model show that up to 100 species can coexist for at least 10 000 generations, and that even small population sizes or species with inferior competitive ability can survive when there is intra-specific variability. In nature, this variability can be observed as niche differentiation, variability in environmental and ecological factors, and variability of individual behaviours or physiology. Therefore, previous specific explanations of the paradox are consistent with and provide specific examples of our suggestion that individual variability is the mechanism which solves the paradox. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Publication Title, e.g., Journal

Journal of the Royal Society Interface

Volume

11

Issue

95

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