Effect of salt on algal biomass. The experiment was carried out with three different salinities (30, 35, 40 g l-1) of BG11 medium with a deficient amount of NaNO3 (0.75 g l-1) with Clorella sp. These conditions were chosen to simulate sea water salinity. The salinity was adjusted by the addition of commercial NaCl (Poch, Poland).