Organizing principles for marine microbial consortia

J. Jeffrey Morris and Laura R. Hmelo

Full Citation: Morris, J. Jeffrey and Laura R. Hmelo, 2014. Organizing principles for marine microbial consortia. p. 1-15. In P.F. Kemp [ed.], Eco-DAS IX Symposium Proceedings. ASLO. [doi: 10.4319/ecodas.2014.978-0-9845591-3-8.1]

ABSTRACT: Microbiologists commonly speak of microbial communities, but the degree to which assemblies of microbes are governed by the rules of classical community ecology is unclear. Specifically, microbes are much more easily dispersed, and have much faster growth rates, than macroscopic organisms, potentially changing the relative importance of various forces in community assembly. In the well-mixed, liquid environment of the pelagic ocean, these differences are likely to be most pronounced (and most easily studied). Here we develop a framework for understanding community assembly in marine microbial populations. We begin by constructing a simple neutral model that predicts what consortia should look like if they are randomly assembled. From there, we consider what rates determine whether consortia will persist long enough to form a “climax” community. With these possibilities representing “extremes,” we explore possible intermediate successional stages driven by lottery competition for space and/or local co-evolution toward cooperative exclusion of other species. We further discuss what empirically measurable traits we would expect to exist under these four different scenarios and suggest experiments to distinguish between these possibilities.