Microalgae are prokaryotic or eukaryotic photosynthetic microorganisms that can grow rapidly and live in a wide range of ecosystems extending from terrestrial to aquatic environment. Environmental factors such as temperature, UV-light, irradiance, drought and salinity are known to affect their photosynthesis. Photosynthesis was the most sensitive process in microalgae, leading to numerous changes in structure and function of the photosynthetic apparatus under various conditions. The photosynthetic response may be involved in the modification of energy collector complexes, antennas, or reaction centers and in the distribution of excitation energy between the two photo systems (PSII and PSI)
