European Diatom Database-Swedish Dataset

The training set from northern Sweden is an extended 151 sample set that includes the 119 lakes published in the training set assembled by Korsman & Birks (1996). The lakes are head-water sites (maximum depth > 2m; 0.04-2 km2; altitude > 5m; not limed).

Sediment samples were taken with a gravity corer from the deepest point of each lake. With a few exceptions, that were analysed only once, water chemistry data were means of summer and winter values for the period 1985-1989. 200-300 diatom valves were counted per surface sediment sample. Only diatom taxa occurring in at least 5 lakes with a relative abundance of more than 2% in at least one lake were included in the analyses, giving at total of 115 taxa in the training set.