Resilience in bacterial communities
To understand how population dynamics drive evolution and how evolution shapes population dynamics we are working on understanding how bacterial communities evolve resilience to perturbations. Evolution is a major contributor to microbial community structure and dynamics. Sequencing analysis of natural communities have shown that mutation and selection, adaptive radiation, competition, and niche formation all contribute to shape the structure and dynamics of microbial communities.
The fact that resilience is an important feature of microbial communities and evolution plays a defining role in community structure and dynamics pose several questions: How does community resilience evolve? How does resilience depend on the history of environmental perturbations or the species present?
We have developed a new, broadly applicable, technique for measuring community dynamics by automated single cell imaging (Scientific Reports, 2016). The technique permits measurements of dynamics on a timescale of few minutes for periods of weeks.
We recently showed that bacterial communities exhibit very long memory -- the history of environmental disturbances alters how the community responds to future disturbances (arxiv, 2017). Community memory results from the transmission of information through several generations. Future work will be directed towards understanding evolution and dynamics in more complex communities.
(Video of cells imaged in the capillary)
We have constructed six replicate devices. Our method permits the long-term (weeks to months) measurement of abundance dynamics in model bacterial communities. Below is an example time series of a single species community of Escherichia coli over a period of ~25 days. The community is subject to periodic perturbations.