European Diatom Database-Swedish 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 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. This calibration set was
developed for a palaeolimnological study of lake acidification in northern
Sweden.