Cyanobacteria/algae growth follows Monod kinetics: growth rate depends on light and nutrient availability, with a thermal optimum. Photosynthesis converts CO2 into biomass and O2 in proportion to growth rate; mixing keeps cells suspended and gas-exchanging.
mu = mu_max * (I/(Ks_I+I)) * (S/(Ks_S+S)) * f(T)
dX/dt = mu * X - harvest
O2_rate, CO2_rate proportional to mu * X
- Light intensity - drives the photosynthetic (I/(Ks+I)) term; too little light starves growth.
- Nutrient feed rate - sets the Monod nutrient term; too little limits growth even in bright light.
- Temperature - a Gaussian thermal-optimum curve centred near 30 °C; too hot or cold suppresses μ.
- Mixing - keeps cell instances suspended and circulating; low mixing lets biomass settle and reduces effective gas exchange.
- Harvest button - removes 30% of current biomass instantly, mimicking a bioreactor draw-down cycle.
Real-world application: this is the core control loop engineers tune in proposed microbial terraforming/bioregeneration reactors that scrub CO2 and regenerate breathable O2 for closed habitats.