Cladoceran remains as indicators of lake acidification

Wide gaps in the records of limnological parameters from the past 30 to 50 years prevent a documentation of lake acidification. To solve this problem, methods must be found to infer former pH-conditions from sub-fossils. Therefore cladoceran remains were studied in undisturbed sediment cores of selected, poorly buffered lakes in the F.R.G. As a result, a correlation was found between the lakewater pH and the species composition of the assemblage of chydorid cladocerans. This correlation is highly significant and points out the distinct influence of low pH values (< 7) on this group of organisms. Reconstruction of the pH-history of three studied lakes evidences that acidification of poorly buffered lakes in the F.R.G. has taken place, even though it was not noticed previously.