Astro-Seminar: Greg Cooke - Ecological modelling of hycean worlds

Abstract: New observations are opening the possibility of characterising habitable environments in exoplanetary systems. We apply the Lotka–Volterra (predator-prey) equations to exoplanet ecology for the first time, modelling between 1–5 anoxic bacterial species within a vertical water column applied to hycean worlds. We demonstrate that dominating phototrophic bacteria at the top of a water column out-compete deeper dwelling phototrophic bacteria, analogous to bacterial blooms on Earth. Incorporating microbial viruses (bacteriophages) within our models can cause ecosystem collapse depending on the time of their introduction, and such phage inclusion can be beneficial to ecological diversity. Finally, our work shows that bacterial populations inhabiting tidally locked exoplanets may be more stable due to constant illumination of the ocean but can have lower peak population densities in such cases when compared to seasonal scenarios. Our work provides an initial step towards understanding the possible ecological diversity on habitable worlds beyond Earth. 

arXiv paper link: https://arxiv.org/abs/2603.22491