European Diatom Database - NW Europe Dataset

The European Diatom Database (EDDI) is a web-based information system designed to enhance the application of diatom analysis to problems of surface water acidification, eutrophication and climate change.

The Northwest European dataset is an amalgamation of six smaller regional datasets from southeast England, the English Midlands, Wales, Northern Ireland, Denmark, and Sweden. The lakes are mostly lowland, shallow, small, slightly acid to alkaline waters with agricultural activity and/or forestry in the catchments. The combined dataset spans a long TP gradient from oligotrophic to hypertrophic waters. Surface sediment samples (0-1 cm) were collected from the deepest point of each lake over the period 1990-1993 and diatoms were counted by either Helen Bennion (southeast England, meres, Wales), John Anderson (Northern Ireland, Denmark, Sweden) or Tim Allott (Wales). A program of taxonomic harmonisation was undertaken to construct a unified database of diatom data. The full dataset consists of 164 lakes but this was reduced to a training set of 152 lakes following data screening. This training set was used to develop a WAPLS diatom-TP transfer function and component 2 gave the lowest prediction error (RMSEP=0.21 log10TP �g l-1, apparent r2=0.91). Further details of the training set and transfer function are given in Bennion et al., 1996) and the model has subsequently been applied to numerous diatom sequences to reconstruct lake nutrient histories (e.g. Bennion et al., 1996, 1999, 2000, 2001).