Photon statistics and unicellular algae cultivation characteristics under continuous illumination

Despite the complexity of the photosynthetic system, a simple explanation is proposed for the photon-flux density dependence of P-I curves (biomass production rate versus flux density) and electron transfer rate curves (delivery transfer rate of excited electrons from PS II, the first stage of the photosynthetic process, to the second stage, PS I, versus flux density). It is shown that the photon-flux density dependence of these two entities is a direct consequence of the stochastic nature of photon arrival times on the chlorophyll antenna of PS II, the existence of a rate-limiting time scale of about 10 ms in the operation of the photosystem, and the magnitude of the average photon absorption cross-sectional area of the chlorophyll antennae.