Chlorophyll-a measurements on the Dutch continental shelf, Delta and the Dutch Wadden Sea between 2000 and 2021

Data consists of Chlorophyll-a measurements (year round in monthly intervals) and phytoplankton cell counts (partly year round in monthly intervals or more). Surface water samples were taken and preserved with Lugols. In stratified waters, samples of the thermocline and bottom were taken with Niskin samplers. Analysis was carried out with determination of species to the lowest taxonomic rank possible by inverted (Utermohl) microscopy including fluorescence techniques for potentially toxic dinoflagellates like Alexandrium.