Cyclic di- and tri-sulfides bearing the carbon skeleton of phytol, the C20 isoprenoidal alcohol side chain of chlorophyll a, have recently been recovered from the organic extracts of various marine sediments. This finding and related others imply that labile biomarkers undergo reaction with reduced forms of sulfur such as polysulfide during early diagenetic processes in recent sediments. Few studies to date have examined the recent sediment record systematically to retrieve more specific details of this geochemical phenomenon and to assess the importance of sulfur "quenching" as a viable mechanism of preservation for labile biomarkers. A multidisciplinary geochemical approach will be used to explore this problem intensively. The overall goal of the research is to develop a reliable method of extracting quantitative biomarker information from the sedimentary component of total organic carbon that is diagenetically modified by reactions with sulfur. Such information when complemented with biomarker data obtained from sediments by more conventional methods might prove invaluable to paleoceanographic research.
