Concentrations of beta-carotene, astaxanthin, canthaxanthin, and diatoxanthine of ODP Leg 112 samples (Table 2)
2019-11-22T18:44:24Z (GMT) by
The quantitative distribution of carotenoids in sediments of Pleistocene to Miocene age from the Peru upwelling area is reported. Major pigments include beta-carotene, diatoxanthin, caroteno-3,3'-diols from phytoplankton, astaxanthin and canthaxanthin from crustaceans, and spheroidenone from bacteria. beta-carotene epoxides are major consituents, representing transformation products in the degradation of beta-carotene to low molecular weight compounds. The absolute abundance of carotenoids reflects bottom-water oxicity at the time of deposition; highest concentrations of carotenoids were observed in laminated muds deposited within the oxygen-minimum zone, with reduced or negligible concentrations of pigments observed in bioturbated sequences deposited during periods of well-oxygenated bottom water. beta-carotene, the most abundant pigment in recently deposited sediments, slowly degrades through a sequence of transformation reactions initiated by epoxidation. The 4,4' dioxo-carotenoids, which are unable to form 5,6-epoxides, have been preferentially preserved in these sediments.