The photosynthetic oxygen evolution will be measured in cultures of P. tricornutum, Nannochloropsis sp. and Porphyra sp. inside a photosynthetic chamber. A total of 22 different red, blue and green LEDs combinations will be tested at three different light intensities (50, 100 and 500 µmol s-1 m-2) and biomass concentrations (0.2, 2 and 5 g L-1).