<p>The KPLANK database includes phytoplankton data from 1963 to present, covering the Finnish coastal areas and offshore areas of the Baltic Sea. The quantitative data mainly stem from the Finnish national monitoring program and statutory monitoring programs. The database contains approximately 240 000 quantitative records including size classes. In this dataset results are provided per taxon, i.e. size classes are not included. The data available through EMODnet should not be used as is for phytoplankton community analyses, as the dataset only includes taxonomic units with a valid AphiaID. Practical identification units, which are not strict taxonomical units and therefore lack an AphiaID, include e.g. the very common spring bloom dinoflagellates collectively termed the Scrippsiella complex and unidentified single nano-sized coccoid cells (i.e. cells lacking flagella). For phytoplankton community analyses it is needed to contact the data provider. All original data from KPLANK database, including all taxonomic units and size class data are available from the data provider upon request. The database is regularly maintained and data is added continuously.</p>