Lipid and DNA features of Gonyaulax fragilis (Dinophyceae) as potential biomarkers in mucilage genesis

Due to the increasing evidences on dinoflagellate contribution to mucilage phenomena in the Mediterranean Sea, this study was aimed at identifying biochemical and/or genetic markers that could help in relating Gonyaulax fragilis growth with mucilage formation when microscope identification was difficult. The biochemical characterization considered the fatty acid and sterol composition of cultured strains and mucilage samples. The cultured algae displayed the typical fatty acid pattern of dinoflagellates as the 18:0 was the prevalent saturated fatty acid (SFA), 18:1n-7 and 18:1n-9 were the major monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) were dominated by 18:5n-3 and 22:6n-3. Two groups of sterols were identified in algal cells: desmethylsterols, dominated by cholesterol and β-sitosterol, and 4α-methylsterols, having dinosterol as the prevailing sterol. The mucilage lipid pattern was characterized by low amounts of PUFAs and appeared deeply influenced by environment dynamics; however, the 20:5n-3/22:6n-3 ratio