ALKANOL AND STEROL DEGRADATION IN A SEDIMENT CORE FROM THE CONTINENTAL-SLOPE OFF SOUTHWESTERN TAIWAN

A sediment core (ca. 36 cm in length and sectioned at 4 cm intervals) collected from the ano;dc continental slope off southwestern Taiwan ha s been analyzed for alkanols and sterols in the extractable and bound forms to understand their degradation in this reducing environment dur ing diagenesis. Generally speaking, the two compound classes (both ext ractable and bound) degrade faster in the upper core and slower in the lower core; however, extractable phytol degrades sharply from section s 1 to 2 and gradually from section 2 down. The calculated apparent ra te constants (y(-1)) for the extractable phytol, Sigma n-alkanols, and Sigma sterols are respectively 0.015, 0.011, and 0.010; and those for the bound phytol Sigma n-alkanols, and Sigma sterols are respectively 0.011, 0.007 and 0.007. The bound form is slightly less reactive than the extractable form These constants are at least one order of magnit ude lower than those reported for two shallow coastal marine sediments --Cape Lookout Eight and Peru, but are similar to or slightly lower th an those reported for the anode Black Sea deep basin. The interesting result can be attributed to anoxicity which plays the most important r ole during lipid degradation in the sediment. (C) 1997 Elsevier Scienc e Ltd.