Physics (Internal)

"The fate of microbial invaders in multi-stable laboratory ecosystems"

This event is part of the Biophysics Seminars. 12:30PM.

Microbial communities are frequently challenged by the arrival of new species that could spread in the community, potentially leading to long-term shifts in community state. This argues for a deeper understanding of how invasions can interfere with the dynamics of microbial communities. In this talk I will show different community dynamics scenarios resulting from microbial invasions observed in laboratory ecosystems. Firstly, I will analyze the spatial dynamics of bacterial mutualists to show that, while invading new territories, improved environments can slow down the speed of the range expansion. Moreover, I will cover more complex situations in which an interaction network considering two alternative mutualistic mechanisms (here, cross-feeding and cross-protection) maintains a high biodiversity at the edge of the front. I will then focus on a bistable model system to study the dynamics between alternative stable states in microbial ecosystems. By introducing an invading species into the system, we observed that the invading species can induce transitions between these alternative stable states. Interestingly, in many cases the invading species did not survive in the final community state, making these species what we call a “transient invader.” This suggests that short-term invasions (such as infections) could be a common mechanism driving transitions between stable states in microbial communities.