Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments

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	Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments
	Wang, Xu-Chen 1,2; Sun, Ming-Yi 3,4; Lil, An-Chun 1
刊名	JOURNAL OF OCEANOGRAPHY
	2008-04-01
卷号	64 期号:2 页码:311-321
关键词	Organic Biomarker Stable Carbon Isotope Sediment Changjiang River Estuary East China Sea Shelf
ISSN号	0916-8370
文献子类	Article
英文摘要	To examine the source and preservation of organic matter in the shelf sediments of the East China Sea (ECS), we measured bulk C/N and isotopes, organic biomarkers (n-alkanes and fatty acids) and compound-specific (fatty acids) stable carbon isotope ratios in three sediment cores collected from two sites near the Changjiang Estuary and one in the ECS shelf. Contrasting chemical and isotopic compositions of organic matter were observed between the estuarine and shelf sediments. The concentrations of total n-alkanes and fatty acids in the shelf surface sediments (0-2 cm) were 5-10 times higher than those in estuarine surface sediments but they all decreased rapidly to comparable levels below the surface layer. The compositions of n-alkanes in the estuarine sediments were dominated by C(26)-C(33) long-chain n-alkanes with a strong odd-to-even carbon number predominance. In contrast, the composition of n-alkanes in the shelf sediment was dominated by nC(15) to nC(22) compounds. Long-chain (> C(20)) fatty acids (terrestrial biomarkers) accounted for a significantly higher fraction in the estuarine sediments compared to that in the shelf sediment, while short-chain (< C(20)) saturated and unsaturated fatty acids were more abundant in the shelf surface sediments than in the estuarine sediments. Stable carbon isotopic ratios of individual fatty acids showed a general positive shift from estuarine to shelf sediments, consistent with the variations in bulk delta(13)C(TOC)TOC. These contrasts between the estuarine and shelf sediments indicate that terrestrial organic matter was mainly deposited within the Changjiang Estuary and inner shelf of ECS. Post-depositional diagenetic processes in the surface sediments rapidly altered the chemical compositions and control the preservation of organic matter in the region.; To examine the source and preservation of organic matter in the shelf sediments of the East China Sea (ECS), we measured bulk C/N and isotopes, organic biomarkers (n-alkanes and fatty acids) and compound-specific (fatty acids) stable carbon isotope ratios in three sediment cores collected from two sites near the Changjiang Estuary and one in the ECS shelf. Contrasting chemical and isotopic compositions of organic matter were observed between the estuarine and shelf sediments. The concentrations of total n-alkanes and fatty acids in the shelf surface sediments (0-2 cm) were 5-10 times higher than those in estuarine surface sediments but they all decreased rapidly to comparable levels below the surface layer. The compositions of n-alkanes in the estuarine sediments were dominated by C-26-C-33 long-chain n-alkanes with a strong odd-to-even carbon number predominance. In contrast, the composition of n-alkanes in the shelf sediment was dominated by nC(15) to nC(22) compounds. Long-chain (> C-20) fatty acids (terrestrial biomarkers) accounted for a significantly higher fraction in the estuarine sediments compared to that in the shelf sediment, while short-chain (< C-20) saturated and unsaturated fatty acids were more abundant in the shelf surface sediments than in the estuarine sediments. Stable carbon isotopic ratios of individual fatty acids showed a general positive shift from estuarine to shelf sediments, consistent with the variations in bulk delta(CTOCTOC)-C-13. These contrasts between the estuarine and shelf sediments indicate that terrestrial organic matter was mainly deposited within the Changjiang Estuary and inner shelf of ECS. Post-depositional diagenetic processes in the surface sediments rapidly altered the chemical compositions and control the preservation of organic matter in the region.
学科主题	Oceanography
语种	英语
WOS记录号	WOS:000253545400016
公开日期	2010-12-24
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/5065]
专题	海洋研究所_海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Oceanog, Qingdao 266071, Peoples R China 2.Univ Massachusetts, Dept Environm Earth & Ocean Sci, Boston, MA 02120 USA 3.Univ Georgia, Dept Marine Sci, Athens, GA 30602 USA 4.Ocean Univ China, Coll Chem & Chem Engn, Qingdao 266003, Peoples R China
推荐引用方式 GB/T 7714	Wang, Xu-Chen,Sun, Ming-Yi,Lil, An-Chun. Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments[J]. JOURNAL OF OCEANOGRAPHY,2008,64(2):311-321.
APA	Wang, Xu-Chen,Sun, Ming-Yi,&Lil, An-Chun.(2008).Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments.JOURNAL OF OCEANOGRAPHY,64(2),311-321.
MLA	Wang, Xu-Chen,et al."Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments".JOURNAL OF OCEANOGRAPHY 64.2(2008):311-321.