Periphyton pigment analyses using paper chromatography

Abstract

Paper chromatography was used to study the community structure, the proportion of degraded chlorophylls to the total pigment content, and the chlorophyll and carotenoid content of the epilithic periphyton algae from Lake Tahoe, California-Nevada. Analyses were made using both samples directly from the lake and cultured periphytic algae. The extraction was made with boiling 100% methanol; two dimensional chromatography was used to separate the pigments. The relative contribution of different pigment fractions to total light absorption by the complete periphyton extract was estimated by planimetric integration of absorption curves. From the pigment structure, estimates were made of the proportions of different algal groups in the samples. Further, the results gave information on the proportions of active and degradated forms of chlorophyll a, as well as the chlorophyll a content per unit biomass. The results showed the rarity of phaeophytin a in the epilithic algal communities in Lake Tahoe, but often some proportion of chlorophyll a occurred as other forms of pigment degradation products. The percentage of chlorophyll a of the complete pigment extract varied according to environmental conditions, and the productivity and vitality of the algae.