Since 1962 phytoplankton and microzooplankton composition are monitored every weekday at the station "Kabeltonne" (54°11.3′N, 7°54.0′E) as part of the Helgoland Roads long term data series. This collection contains data sets of the abundance of single species/taxa of the phytoplankton community and total abundances of wider taxonomic groups. A description of the methodology can be found in the method guide. Meta-information on specific adjustments to protocols, details about calibrations and maintenance of devices, specific limitations of datasets and further documentation are also provided in the section "Documentation" of this collection.