European Diatom Database-ALPE Mountain Lake Dataset

The ALPE training set is from high-altitude or high-latitude lakes in the Alps, Norway, Svalbard, Kola Peninsula, UK, Slovenia, Slovakia, Poland, Portugal, and Spain. Gravity or piston corers were used to collect surface-sediment samples of 0.25 or 0.5 cm thickness, usually from the deepest point in each lake and a total of at least 500 valves were counted from each sample.

A large number of possible sites in existing calibration sets, plus new ALPE project sites, were first screened carefully to select a set of lakes meeting the criteria of an alpine or remote location and an undisturbed catchment. The resulting ALPE data set of 118 lakes is derived from the whole or parts of 5 data-sets. These are 31 lakes from a Central Alps data set (Marchetto & Schmidt, 1993), 28 lakes from a Pyrenean data set (Garcia & Catalan, unpub.), 30 AL:PE 1 and AL:PE 2 lakes in various countries, 9 lakes from a Norwegian diatom-pH data set (Birks, Boyle & Berge, unpub.), and 20 Norwegian, Welsh, and Scottish lakes from the SWAP calibration set (see above).