CHLOROPHYLL DERIVATIVES, SULPHUR, AND CARBON IN SEDIMENT CORES FROM TWO ENGLISH LAKES

Abstract

Chlorophyll derivatives, sulphur, and carbon exhibit similar trends in each of two sediment cores, one from the fertile Esthwaite Water and the other from the unproductive Ennerdale Water. In Esthwaite Water maximum levels of all three constituents were reached early in the course of lake development, while in Ennerdale Water maxima were attained much later, and, in the case of chlorophyll derivatives and sulphur, were much lower than in Esthwaite. Relatively high optical densities of acetone extracts between 400 and 500 mμ suggest the presence of carotenoids in surface muds from Esthwaite Water. Much lower optical densities were recorded for this wave-length range in extracts of deeper sediments from Esthwaite and all sediments from Ennerdale. Low ratios of optical density at 410 mμ to density at 350 mμ are characteristic of surface sediments from infertile lakes such as Ennerdale Water, and of woodland soils. However, higher ratios near to those observed throughout the Esthwaite core were found in the deeper Ennerdale sediments, with the exception of the deepest sample.Ratios of chlorophyll derivatives to carbon and of sulphur to carbon were higher in the more fertile Esthwaite Water, although relatively low ratios during the earliest stages of development indicate that this lake may have been less fertile then. In Ennerdale Water the ratio of chlorophyll derivatives to carbon exhibited a much slower rise to maximum values than in Esthwaite, and these maxima were much the same as the early Esthwaite minima. The ratio of sulphur to carbon was also consistently lower in Ennerdale Water.