title: [Composition of n-alkanes in soils of the Yellow River Estuary Wetlands and their potential as organic matter source indicators].
abstract: Abstract: Surface soil samples from the Yellow River Estuary Wetlands were analyzed for total organic carbon (TOC) and n-alkanes. Molecular indicators of n-alkanes were calculated and their potential as organic matter source indicators was discussed and compared among different sampling areas and times. C25-C33 n-alkanes with odd-to-even predominance were observed in most surface soils of the wetlands, suggesting the dominant contribution of terrestrial higher plants for the soil organic matter (SOM), and the ubiquitous presence of unresolved complex mixture indicated the presence of petroleum contamination. Total n-alkane concentrations in soils varied from 0.57 microg x g(-1) to 3.90 microg x g(-1), and distinct spatial and temporal differences were observed. In April 2009 (dry season), total n-alkane concentration was higher than that in June 2009 (during water-sediment regulation) with the maximum concentration observed at the core area of the wetlands, followed by the north side of the Yellow River after the last pontoon bridge, and the abandoned channel area of the Yellow River. The opposite trend of total n-alkane concentration was observed in June. The variation of total n-alkane concentration at two sampling time points were positively correlated with TOC and negatively correlated with sediment grain size, suggesting the influence of hydro-environment on the accumulation of soil organic matter. Molecular indicators of n-alkanes, such as average chain length (ACL), odd-even predominance (OEP), alkane index (AI), carbon preference index (CPI) and Terrigenous/ Aquatic Ratio (TAR) indicated that the maturity of organic matter in soils of the wetlands was low, and the dominant source of the SOM was terrestrial higher plants and mainly herbaceous plants. Compared with other indicators, TAR is better in reflecting the variation of hydro-environment.
authors.affiliation: Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China. yaopeng@ouc.edu.cn
authors.forename: Peng
authors.initials: P
authors.lastname: Yao
authors.forename: Hong-Zhen
authors.initials: HZ
authors.lastname: Yin
authors.forename: Qing-Zhen
authors.initials: QZ
authors.lastname: Yao
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Chen
authors.forename: Yue-Liang
authors.initials: YL
authors.lastname: Liu
mesh_terms: D000473:Alkanes / Q000032:analysis / Q000737:chemistry*; D002244:Carbon / Q000032:analysis; D002681:China; D017753:Ecosystem; D063366:Estuaries; D009930:Organic Chemicals / Q000032:analysis; D045483:Rivers / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D053833:Wetlands
chemical_list: D000473:Alkanes; D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; D002244:Carbon