The Stable Carbon Isotopic Compositions of n-Alkanes in Sediments of the Bohai and North Yellow Seas: Implications for Sources of Sedimentary Organic Matter

• 作者: DANG Tianxiang CAO Yunyun XING Lei
• 来源期刊: 中国海洋大学学报（自然科学英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: Marine and Atmospheric Sciences
• 页码范围: 340-348
• 页数: 9页
• 语种: 英文

摘要

Stable carbon isotopic compositions of n-alkanes in surface sediments of the Bohai and North Yellow Seas were inves-tigated to elucidate sources of sedimentary organic matter in these seas. The long-chain n-alkanes in surface sediments are predomi-nantly long-chain C27, C29, and C31 types, with obvious odd carbon predominance. The δ13C values of long-chain n-C27, n-C29, and n-C31 alkanes are -30.8％ ± 0.5‰, -31.9％ ± 0.6‰, and -32.1％ ± 1.0‰, respectively, within the range of n-alkanes of C3 terrestrial higher plants. This suggests that sedimentary n-alkanes are derived mainly from terrestrial higher plants. Compound-specific carbon isotopic analysis of long-chain n-alkanes indicates that C3 terrestrial higher plants predominate (64％–79％), with angiosperms being the main contributors. The n-alkane δ13C values indicate that mid-chain n-alkanes in sediments are derived mainly from aquatic emergent macrophytes, with significant petroleum pollution and bacterial degradation sources for short-chain n-alkanes.