Project: Assembly and Dynamics of Multi-Species Microbial Communities
Given our increasing appreciation of the impact of complex microbial communities, we seek to better understand the dynamics and outcomes of the microbial community assembly process. For this project, we will develop a model system using a set of 32 marine bacterial strains that the Cordero Lab has isolated from coastal seawater. This set of natural isolates covers a broad taxonomic range, and is characteristic of the diverse microbial communities found in nature.
First we will characterize the number of coexisting species as a function of the number of species that are competed together. Some theory based on Lotka-Volterra modeling suggests that the number of surviving species should grow logarithmically with the number of species that are added. Moreover, it would be interesting to measure the diversity as a function of the diversity and quality of resources in a defined media. We are also interested in testing whether there are more positive interactions between species in more challenging environments.
Next, we will explore the possibility of alternative stable states—that is, different stable outcomes arising from different initial species abundances—in this experimental microbial system. While simple mathematical models of multispecies communities (e.g. Lotka-Volterra) do indeed predict the existence of alternative stable states, experimental data would help us understand the ecological forces driving this phenomenon. In addition, we will use time series data to distinguish between stable states and dynamical “equilibria” such as limit cycle oscillations or chaos.
Finally, we are also interested in competition between microbial communities. For these experiments we will compare the final species composition of many 8-species competitions together with the final species composition when two of these 8-species communities are competed. Does the final community of this 16-species competition tend to look like one of the two 8-species competitions? If so, then this would represent a form of competition at the community level rather than strictly at the species level.
Jeff Gore is an associate professor of physics at the Massachusetts Institute of Technology. He joined the MIT physics department as an assistant professor in January 2010 after spending the previous three years in the department as a Pappalardo fellow working with Alexander van Oudenaarden. With the support of a Hertz graduate fellowship, in 2005 he received his Ph.D. in physics from the University of California, Berkeley. His graduate research in single-molecule biophysics was done in the laboratory of Carlos Bustamante, focusing on the study of twist and torque in single molecules of DNA. Gore is excited to be in the physics department at MIT, particularly since this is where he studied as an undergraduate in the late ’90s.