Collated for the purposes of intercalibrating the outputs of the Central Baltic GIG WFD phytoplankton classification tools. Includes data from large number of lakes across the GIG region, provided by the participating countries. Raw phytoplankton data is provided as biovolumes. Raw supporting physico-chem data also included for appropriate time periods. Typology information also included. Note that not all data from this dataset will be made available to BioFresh science work packages or the portal. More information on this dataset can be found in the Freshwater Metadatabase - BFE_31 (http://www.freshwatermetadata.eu/metadb/bf_mdb_view.php?entryID=BFE_31).