The Evolution of Stenols and Stanols in Marine Sediment Core From Beibuwan Gulf, South China Sea

Abstract: The distribution of stenols and stanols were examined in leg 4-60-65(0-465cm)of marine sediment core from Beibuwan gulf of South China sea.Ten sterols named as Cholest-5-en-3β-o1; 5x-Cholest-3β-ol; 24-MethylchoIest-5, 22-di-en-3β-ol; 24-Methyl-5x-cholest-22-en-3β-ol; 24-Methylene cholest-5-en-3β-ol: 24-Methyl-5x-cholest-3β-ol; 23, 24-di-methy-lcholest-5, 22-di-en-3β-ol; 23, 24-Dimethyl-5x-cholest-22-en-3β-ol; 24-Ethylcholest-5-en-3β-ol; 24-Ethyl-5α-cholest-3β-ol have been identified by means of gas chromatography-mass spectromatry-data system. A high concentration of C₂₇ sterols were mainly originated from zooplankton lipids. the C₂₈ sterols were derived from diatom, the C₂₇-C₂₉ sterols were observed in various species of green and red algae, the C₂₉ 24-Ethylcholest-5-en-3β-ol as a biomarker is thought to indicate input of terrigeous organic matter, the C₂₇-C₂₉ sterols as a ecological indicator to recognize the source of organic matter in marine. These sterols are mainly come from zooplankton in marine environment. The results show that the C₂₇ C₂₈ and C₂₉ 5x-stanol/△5 stenol ratio increase with sediment depth, that means the evolution of sterols occur in the reducing environment of deeper marine sediments from Beibuwan gulf of South China Sea.