The MAP-IO (Marion Dusfresne Atmospheric Program - Indian Ocean) program aims to make up for the lack of observation in this region of the earth by equipping the Marion Dufresne vessel (https://taaf.fr/en/marion-dufresne-and-astrolabe/) with a set of in-situ instruments and remote sensing for the atmosphere and marine biology studies. This program has been labeled by the French Commission Nationale de la Flotte Hauturière (CNFH, https://www.flotteoceanographique.fr/) for the period 2021 to 2024. During this period, MAP-IO will operate as a scientific program for the acquisition and scientific enhancement of four years of data. This period will also serve as an operational prototype to study the feasibility of switching the program to a permanent observatory aimed at integration into international infrastructures networks such as ACTRIS (https://www.actris.eu/) or ICOS (https://www.icos-cp.eu/). More informations on the project : http://www.mapio.re/. MAP-IO is a scientific program led by the University of La Reunion (LACy and OSU-R) and was funded by the European Union through the ERDF programme, the University of Reunion, the SGAR-Réunion, the Région Réunion, the CNRS, IFREMER and the Flotte Océanographique Française. The Cytosense automated flow cytometer from the cytobuoy compagny was installed onboard the Marion Dufresnes Sea Water supply, to run semi continuously samples for phytoplankton functional groups resolution. Sample acquisition was schedulled once avery two hours. The data corresponds to abundances in cells/ml, mean forward scatter and red fluorescence in arbitrary units, per group. The groups are identified as standard groups following the BODC F02 vocabulary and the corresponding selections sets named following expert names.