GRAIN-SIZE EFFECT ON BOUND LIPIDS IN SEDIMENTS OFF NORTHEASTERN TAIWAN

Two box-core sediments off the northeastern Taiwan coast have been col lected and examined for the relationship between bound lipids and grai n size in the mud fraction (< 63 mu m). No grain size effect was found for the concentrations of Sigma n-alkanes, Sigma n-fatty acids and Si gma n-alcohols. The ratios of branched-chain to normal fatty acids inc reased progressively with decreasing particle size and correlated high ly with BOC (bound organic carbon), suggesting an increasing bacterial input. Moreover, we observed an increase in the ratios of monounsatur ated to saturated fatty acids with decreasing grain size, pointing to an increasing microbial contribution. Particularly interesting is phyt ol, which demonstrated a remarkable grain size effect; the phytol to B OC ratio increased sharply with decreasing particle size. Major sterol s normalized to BOC increased progressively with a decrease in grain s ize and correlated highly with BOC. The results indicate that a plankt on contribution to phytol and sterols increased as particle size decre ased. The grain size effect is stronger for phytol than for sterols an d branched-chain fatty acids in the sediments.