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 M onounsaturated Fatty Acids (MUFA) were 18:1ω-9c (22%) and 16:1ω-7 (4%), main Polyunsaturated Fatty Acids (PUFA) were 18:2ω-6c (19%) and 20:4ω-6c (8%). Phytosterols were the most important sterols in N. scintillans; and stigmasterol was 60 µg/gr and β-sterol was 8µg/gr as the most important ones in phytosterols. α-tocopherol was the highest amount (10.8 µg/g) in lipophilic vitamins. It was found that M alondialdehyde (M DA) was 65 µg/g, total protein was 10 mg/g, Glutathione (GSH) was 10565 µg/g and GSSG) was 49 µg/g. Consequently, PUFA and α-tocopherol were the most important biochemical parameters and α-tocopherol may reduce toxicity in blooms of N. scintillans because of inhibitory effect of α-tocopherol on lipid oxidation. Additionally, we can say that N. scintillans is a resistant dinoflagellate against oxidative stress.