Physics (Internal)

Network Topology and Community Function in Spatial Microbial Communities

This event is part of the Departmental Seminars.

Dissertation Committee: Kirill Korolev, Pankaj Mehta, Shyam Erramilli, Kevin Black and Rama Bansil

Abstract: Multi-species microbial communities perform tasks ranging from the production of biofuels and the release of powerful greenhouse gases to the digestion of food inside our gut. Microbiota in the human body contribute to many dimensions of host phenotype, including diseases such as obesity, diabetes and colitis. In this talk, I demonstrate that microbial inter-dependencies can produce a large number of spurious associations in statistical studies linking specific taxa to the incidence of disease. Using techniques from statistical physics, I propose a method to control for microbial interactions (Direct Association Analysis or DAA) which corrects the skew towards highly significant associations in the largest dataset on inflammatory bowel disease. In the second part of the talk, I explore the relationship between underlying interaction topology and community function in spatial microbial communities. Cooperation between two species is exceedingly stable, while mutualism requiring 3 or more species collapses via a non-equilibrium phase transition. Further, adding pairwise cyclic or reciprocal interactions can stabilize 3-species mutualism. These results suggest concrete strategies to engineer robust microbial consortia and detect cooperative interactions from the patterns of species distribution in space.