Noctiluca scintillans reached the highest abundance (5105 ind/m(3)) in April; and April was an important period in the Black Sea ecosystem because of the seasonal thermocline. While the relationship between temperature and abundance was important (P<0.05, r(2)=-0.8), the relationship was not important between salinity and abundance (P<0.05, r(2)=-0.06); and Chlorophyll-a (Chl-a) and abundance (P<0.05, r(2)=-0.2). It was determined that total lipid was 0.5% in wet weight (WW). It was shown that the main Saturated Fatty Acids (SFA) were 16:0 (24%) and 18:0 (6%), main Monounsaturated Fatty Acids (MUFA) were 18:1 omega-9c (22%) and 16:1 omega-7 (4%), main Polyunsaturated Fatty Acids (PUFA) were 18:2 omega-6c (19%) and 20:4 omega-6c (8%). Phytosterols were the most important sterols in N. scintillans; and stigmasterol was 60 mu g/gr and beta-sterol was 8 mu g/gr as the most important ones in phytosterols. alpha-tocopherol was the highest amount (10.8 mu g/g) in lipophilic vitamins. It was found that Malondialdehyde (MDA) was 65 mu g/g, total protein was 10 mg/g, Glutathione (GSH) was 10565 mu g/g and GSSG) was 49 mu g/g. Consequently, PUFA and alpha-tocopherol were the most important biochemical parameters and alpha-tocopherol may reduce toxicity in blooms of N. scintillans because of inhibitory effect of alpha-tocopherol on lipid oxidation. Additionally, we can say that N. scintillans is a resistant dinoflagellate against oxidative stress.