Keywords: واحد فتوسنتزی; ASII; antenna size of photosystem II; Chl; chlorophyll content of an algae cell; DCMU; 3-(3,4-dichlorophenyl)-1,1-dimethylurea; N; inverse of the Emerson and Arnold number; NPQ; non-photochemical quenching; P; oxygen evolution rate; PBR; photobioreactor;