Is the maximum carbon number of long-chain <Emphasis Type="Italic">n</Emphasis>-alkanes an indicator of grassland or forest? Evidence from surface soils and modern plants

The molecular distribution of long-chain n-alkanes in 62 soil samples collected from diverse locations across eastern China was analyzed. The long-chain n-alkanes were mostly dominated by n-C₂₉ or n-C₃₁, regardless of the overlying vegetation type at each site. The results were compared with those summarized from the literature, covering more than 100 soil samples within China and more than 300 genera of modern plants distributed worldwide. There were similar n-alkane distribution patterns for most genera, with no clear differences among grasses, shrubs, and trees. The evidence from analyses of surface soils and modern plants indicates that the relationship between the molecular distribution of long-chain n-alkanes of surface soils and source vegetation is highly complex, and is influenced by many factors. Further, it is suggested that source vegetation types should not be simply inferred from distribution patterns of long-chain n-alkanes in sediments.