关键词: 南极阿德雷岛;企鹅粪土沉积;生物标志物;粪类甾醇;胆甾酸

Abstract:

We study molecular geochemical compositions of penguin ornithogenic sediment Y2-1 from Ardley Island,West Antarctica.The results showed that nC_(23) was the main n-alkane,which might derive from tundra mosses.The high concentrations of alkenes in sediments suggested slow diagenesis and good preservation of organic matter in the studied area.At the same time,the concentrations of cholestanol and phytol were high.The concentration profiles of cholestanol and cholesterol were similar to those of the bioelements and could be applied as organic proxies for historic penguin populations.C_(18) alkanoic acid was the main acid in the sediments and the concentrations of unsaturated fatty acids were low and C_(18∶2) acid was trace amount in most samples.This might be explained by that the main organic matter source of the sediment was penguin guano and not vegetation.Bile acid exhibited high concentration in the sediments.However,there were only one C_(27) sterene,C_(27) sterol and one C_(27) bile acid in the sediments,which showed that the input of the steroids was simple.High concentrations of the fecal sterol and bile acid and low concentration of sterene showed good preservation of the sterols and bile acids.In summary,the molecular geochemical compositions of the sediments indicated that the sources of the organic matter were relatively simple,and the organic matter was well preserved there.