Parmar et al. (2011) stated that light intensity and photoperiod (light and dark) cycles were one of the important factors that determined the growth rate of themicroalgae. At 20, 30 and 40 ppt,Nannochloropsis sp. and Tetraselmis sp. cultured under control condition had significantly higher (p < 0.05) cell density as compared to the microalgae cultured in the natural condition.These data were highly correlated with the optical density reading throughout the experimental period. At high salinity, the growth of microalgae was suspended due to the accumulation of compatible solutes that act as osmoprotectant to stabilizemetabolismenzymes (Fatma et al., 2007). Research by Bartley et al. (2013) demonstrated that higher salinity resulted in lower cell abundance which was consistent with the present findings of decreased Nannochloropsis sp. and Tetraselmis sp. cultivated at 40 ppt. Culture under natural condition was exposed to high light intensities (1260e39 878 lux) and 12:12 h lightedark period compared to control condition (1588 lux). According to Cheirsilp and Torpee (2012), the growth of Nannochloropsis sp. continuously increased to the maximum level with the increase in light intensity up to 10 000 lux. Finding from this studywas in accordancewith Chen et al. (2011)which reported that the growth of microalgae had been inhibited as the light intensity increased beyond the saturation light intensity.