HE EFFECT OF LOWERED SALINITY OF SEA WATER ON THE GROWTH AND PHOTOSYNTHETIC PIGMENT CONTENT IN THREE STRAINS OF THE MICROALGA <i>PSEUDO-NITZSHIA PUNGEN</i>S (GRUNOW EX. P.T. CLEVE) HASLE, 1993 (BACILLARIOPHYTA)
The effect of lowered salinity on the growth and the content of photosynthetic pigments (PP) of chlorophyll a and of carotenoids was studied in three strains of the microalga Pseudo-nitzshia pungens : PP-07, PP-08, and PP-081. At a salinity of 24‰ the number of cells and PP contents in all P. pungens strains decreased after 1 day of exposure, compared to the control (salinity 32‰); with increasing exposure, these parameters restored to the control level. The number of cells and PP content decreased more significantly after 1 day of exposure to salinity lowered to 16‰. The number of dead cells was the highest at 8 and 4‰ after 1 day of exposure; by the end of the test the number of cells and PP contents were low. It was shown that the strains PP-07 and PP-081 were less tolerant to the effect of lowered salinity than the strain PP-08.