Speakers
Description
Subaerial biofilms (SABs) are microbial communities on air-exposed surfaces that play key roles in biogeochemical cycling and deterioration of built heritage. Their activity and persistence strongly depend on environmental conditions, particularly moisture and carbon availability. A mathematical framework is presented to investigate SAB dynamics and ecology. The model describes SABs as thin mixed biofilm-water layers on stone surfaces and is based on ODEs governing the dynamics of key components - including cyanobacteria and heterotrophs - together with intracellular pools of carbon, nitrogen, and energy. These components interact through dominant metabolic pathways constrained by biotic and abiotic factors. Daily cycles of temperature, humidity, light, and CO$_2$ are incorporated to capture effects on water availability and metabolism.
Simulations explore SAB dynamics in a real-world context and reveal distinct daily windows of microbial activity primarily controlled by water availability and light. Heterotrophs contribute to SAB stability by recycling organic matter and regulating pH. The model assesses long-term stability under future environmental scenarios. While temperature increases alone produce limited effects on SABs, elevated CO$_2$ may enhance carbon fixation and productivity. Relative humidity emerges as the key factor regulating SAB viability through water availability.
