A Microbiological Study of Sediments from the Cumbrian Lakes

Abstract

The microbiology of the benthos of 16 lakes in Cumbria, UK, was studied. The lakes formed a series ranging from oligotrophic to eutrophic, and the results were compared with other surveys of their chemistry and biology. The sediments of the more productive lakes contained more organic matter, Eh [electrode potential] measurements indicated that they were more reduced, and the overlying water was deoxygenated to a greater degree. These results correlated with greater microbial activity, biomass and numbers in the sediments of the richer lakes, as measured by electron transport system activity, ATP and direct counts. The data obtained from the sediments were more variable, and showed poorer agreement with the assumed ranking of the lakes than the results obtained from the water column in this and past surveys. The microbiology of the benthos suggested that the more productive lakes might be considered as a distinct group, but more detailed sampling and careful choice of indicator microorganisms would be required to provide statistically significant evidence for this.