Comparative study of sterols in shelf and slope sediments off northeastern Taiwan

Bottom sediments and suspended matter from the shelf and slope areas off northeastern Taiwan were analyzed for sterol, n-alkanol and n-alkane compositions. The Σ(algal sterols/cholesterol) ratios (mean±1σ) were 1.00±0.31 (n=7) for the shelf sediments, 3.29±0.61 (n=7) for the slope sediments, and 1.54±0.19 (n=3) for the suspended matter. The much higher proportion of cholesterol in the shelf sediments is most likely derived from mollusks in the relict sediments. An additional sterol source for the shelf sediments probably is suspended matter in the water column although the shelf has no apparent sedimentation. Results from phytol and n-alkanols suggest recent inputs of lipids from the water column to the shelf. The stanol/stenol ratios are lower for the older shelf sediments than for the younger slope sediments.