Efectos de la temperatura y la iluminación sobre el crecimiento de dos microalgas: Nannochloropsis gaditana Lubian 1982 y Tetraselmis tetrathele (West) Butcher, 1959.

Abstract

The growth on cross gradients of light nad temperature of the microalgae Nannochloropsis gaditana Lubian, 1982 and Tetraselmis tetrathele (West) Butcher, 1959 were studied. Growths of each of the species were not significantly different (P<0.05) between light intensities of 2,000 and 12,000 lux, but were lower at 35°C in respect of that at 25°C and 30°C, and did not occur at 40°C. The highest density of N. gaditana was reached at 30°C and 12,000 lux with 10.3x10⁶cells/ml while in T. tetrathele look place at 30°C and 25°C and 12,000 lux with 2.5x10⁶ cells/ml. There were not significant differences (P<0.05) in length (3.99±0.36µm) and cellular volume (21.05±2.91µm³) of N. gaditana among the four ligth conditions on each temperature nor between the temperatures for each ligth condition, except in those at 35°C in wich there were no differences between the ligth intensities, but the length (5.66±0.56µm) , the width (5.00±0.65gm) and volume (72.28±3.60µm³)  were bigger than in the rest of the conditions (P<0.05)  and at 35°C great vacuolization and fragmented cloroplasts were observed. In T. tetrathele there were no significant differences (P<0.05) in lenght (14.5±1.03µm), width (11.5±1.35µm) and volume (258.55±58.1µm³)  among the experimental conditions, and this species was slightly more tolerant to high tempertures, although at 35°C cyst formation was observed.