Modelling of Microbial Ecosystems

Microbial ecosystems play a central role in aquatic environments, where their dynamics are strongly shaped by physical drivers and resource availability. Among these drivers, light is a key factor controlling phytoplankton growth, both as an energy source and as a limiting resource whose spatial and temporal variability induces complex dynamics. In this talk, we explore how mathematical modelling and control theory can be used to describe, analyze, and influence microbial ecosystem behavior.

We then investigate how hydrodynamics interacts with light to shape phytoplankton growth. In particular, we propose a coupled modelling framework linking hydrodynamic processes with biological growth dynamics. In this study, we employ a mechanistic model describing photon harvesting at the cellular level and its physiological consequences, including photolimitation and photoinhibition. This formulation allows us to represent how cells respond to fluctuating light conditions induced by mixing and transport. The single-cell description is then extrapolated to the scale of photobioreactors, providing a framework to analyze how hydrodynamics modulates light exposure and ultimately biomass productivity.

The seminar then addresses the challenges that arise when extending these models to larger and more complex ecosystems, such as lakes or coastal environments. These challenges include spatial heterogeneity, transport processes, species interactions, and limited observability. Finally, we discuss perspectives and future applications of modelling and control approaches, with a particular focus on ecosystem monitoring, risk mitigation, and the management of harmful algal blooms.