"Phytoplankton abundance data collected within the framework of the RADIALES time series monitoring program, carried out by the CSIC-IEO. The sampling is undertaken monthly from 1989 at five stations in North and Northwest Spanish shelf.

Samples were taken at several depth strata using Niskin bottles mounted on a CTD rosette. They were fixed with Lugol and preserved until they were analysed at the laboratory under the inverted microscope following the Utermöhl method."