Effects of Selenite and Selenate Toxicity on the Ultrastructure and Physiology of Three Species of Marine Microalgae

The main ultrastructural and physiological changes in cells of Dunaliella tertiolecta, Pavlova lutheri, and Amphidinium carterae treated with selenite or selenate involved the mitochondria and chloroplasts as well as the respiratory and photosynthetic rates. Other changes were observed in the nucleus, lipids, vacuoles, and nitrogen and carbon contents, but these showed greater variability among the microalgae studied. The major alterations suggested that energy-transducing systems were severely affected by selenium toxicity. These led to significant decreases or even elimination of storage products and major reductions in growth.