Ionene: A Thermal Degradation Product of β-Carotene

Abstract
The carotenoid content and xanthophyll/ carotene ratio were determined for the surface horizons of each of nine recent aquatic environments. In general, the concentrations of carotenoids, expressed as a function of organic carbon, were higher in marine than in fresh-water sediments. Xanthophyll/ carotene ratios were all above unity.