Abstract
A new random-walk model was developed to assess light energy absorbed by a photosynthetic microorganism. The model had two parameters, which were determined from transmittance through an algae suspension obtained by opalescent plate spectrophotometry. The validity of the proposed model was confirmed by comparing experimental data of light absorption in a Chlorella ellipsoidea suspension with the computation results of a Monte Carlo simulation, and by comparing light intensities passed through the suspension by a Reinecke’s salt actinometer with those predicted by the random-walk model.