Carbon chemistry of ODP Holes 108-658A and 108-659B (Table 1)

Abstract

Preliminary results of lipid analyses of six samples from Site 658, underlying a present-day active upwelling cell, and of one sample from Site 659 are reported in this paper. Long-chain unsaturated ketones of prymnesiophyceae algae origin are the most abundant compounds in extracts from Site 658, followed by marine-derived steroids. n-Alkanes are of minor importance in these samples, but they predominate in the sample from Site 659. Our interpretation of the results indicates that organic-matter preservation was good to excellent at Site 658 and poor at Site 659, and that an analysis of only aliphatic hydrocarbons leads to an overestimation of the contribution of terrigenous organic matter at Site 658. Increased primary productivity, high sedimentation rates, and oxygen-depleted water masses associated with upwelling are thought to be the key factors for preservation. At the present stage of research, no specific biomarkers have been found that indicate upwelling

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