Biomarker Compositions of Dinoflagellates and Their Applications for

Four motile cells of autotrophic dinoflagellates, Peridinium umbonatum var. inaequale, Akashiwo sanguinea, Scrippsiella tinctoria, and Prorocentrum micans, commonly contain five major sterols: cholesterol, 4-methylcholestan-3-ol, 4, 24-dimethylcholestan-3-ol, dinosterol and dinostanol. A mo-tile cell of heterotrophic dinoflagellate, Protoperidinium crassipes, contains cholesterol, 4, 24-dimethylcholestan-3-ol, dinosterol, dinostanol and 4-tetramethylcholestan-3-ol as major free sterols. Dinosterol concentration of heterotrophic dinoflagellate is about 4–12 times higher than those of autotrophic species, suggesting that the heterotrophic dinoflagellate is important source of dinosterol in some sediments. 4-Methylcholestan-3-ol and 4-tetramethylcholestan-3-ol occur re-spectively in autotrophic and heterotrophic dinoflagellates are believed to serve as potential bio-markers in respective types. Resting cyst of P. inaequale contains 4-methylcholestan-3β-ol, 4, 24-dimethyl-5α-cholestan-3β-ol, dinosterol, dinostanol, and unknown C31 sterol as major free ste-rols. The unknown C31 sterol detected only in resting cyst could have been produced during rest-ing stage. This compound may serve as a potential biomarker for resting cysts of dinoflagellate