Microbial communities routinely have several alternative stable states observed for the same environmental parameters. A possibility of sudden and irreversible transitions between these states (ecosystem-wide regime shifts) complicates the external manipulation of these systems. Can we predict which specific perturbations may induce such regime shifts and which would have only a transient effect? Here I describe several new conceptual models [1-4] that exhibit these emergent phenomena. Two of our models [2,3] were inspired by a decades-old economics work: the stable marriage or stable allocation problem, developed by Gale and Shapley in the 1960s and awarded the Nobel prize in economics in 2012. Using only the ranked tables of competitive abilities of microbes and their nutrient preferences, we determine all stable states of the microbial ecosystem. Each stable state is characterized by a range of environmental parameters (nutrient supply rates) in which it is feasible, that is to say, all of state’s species survive. Finally, we identify the specific environmental perturbations shifting the system from one stable state to another, and analyze a complex interconnected network of transitions between these states.
[1] Goyal A, Maslov S. (2018) Diversity, stability, and reproducibility in stochastically assembled microbial ecosystems. Phys. Rev. Lett., 120, 158102. https://doi.org/10.1103/PhysRevLett.120.158102
[2] Goyal A, Dubinkina V, Maslov S (2018) Microbial community structure predicted by the stable marriage problem. ISME Journal 12: 2823–2834. https://doi.org/10.1038/s41396-018-0222-x
[3] Dubinkina V, Fridman Y, Pandey PP, Maslov S (2018) Alternative stable states in a model of microbial community limited by multiple essential nutrients. BioRxiv 439547 [Preprint]. October 11, 2018. Available from: https://doi.org/10.1101/439547
[4] Wang T, Goyal A, Dubinkina V, Maslov S (2019) Evidence for a multi-level trophic organization of the human gut microbiome. bioRxiv 603365 [Preprint]. April 9, 2019. Available from: https://doi.org/10.1101/603365