Epiphasic Carotenoids in Post‐Glacial Lake Sediments

Abstract

The presence of α‐ and β‐carotenes in surface mud from Lower Linsley Pond, Connecticut, and Little Round Lake, Ontario, was demonstrated by comparing the chromatographic positions and absorption spectra of the isolated compounds with authentic specimens of the same compounds prepared from carrots. Seven other carotenes were isolated from the Lower Linsley Pond mud, three of which were probably myxoxanthin, rhodoviolascin, and lycopene.Carotenoids were found in sediment cores taken from Upper Linsley Pond and Bethany Bog, Connecticut. On the basis of radiocarbon dates and pollen zonations the age of the oldest sediments in these cores was estimated to be approximately 11,000 years. Carotenoids were present in the organic sediments at all depths, but were present in traces or not at all in the basal clay‐silts. Five carotenoid zones of the paper chromatograms were estimated separately using an arbitrary concentration scale: carotene (consisting of α‐ and β‐carotenes and perhaps their cis‐isomers as well), myxoxanthin (?), rhodoviolascin (?), and two unidentified epiphasic carotenoids termed compounds A and B. In the core from Bethany Bog, rhodoviolascin was maximal in the upper part, carotene in the middle, and myxoxanthin and compound B in the middle and lower parts. Myxoxanthin, a pigment of the blue‐green algae, was present only in sediments of the mesotrophic phase of the history of Bethany Bog, and not in those of the dystrophic (bog) phase. The same pigments obtained from the Bethany Bog core were found in a core from Upper Linsley Pond, but the changes in concentration with depth were less striking. A new yellow pigment was present in the Upper Linsley Pond samples.Data on the biochemical composition of mud may be important in determining the kind and amounts of plant tissues incorporated into the mud.