Carbon isotopic composition of sterols in geochemical samples

抄録

Carbon isotopic composition of sterols in marine Holocene sediments, marine sinking particles, tree leaves, and soils were determined. δ¹³C values of algae-derived sterols such as 24-methylcholesta-5, 22-dien-3β-ol and dinosterol in the marine sediments range from −22.1 to −25.2‰, while those of 24-ethylcholest-5-en-3β-ol (24-ethylcholesterol) range from −22.6 to −24.3‰. We conclude that 24-ethylcholesterol in the marine sediments derives from marine algae, because their δ¹³C values are markedly different from those of the leaves of C₃ (∼−29‰) and C₄ (−14‰) plants and similar to those of the algal sterols.