The congress of the AFL (Association Française de Limnologie) and the UOF (Union des Océanographes de France), now entitled the "Journées Internationales de Limnologie et d'Océanographie", will once again be hosted by the University of Aix-Marseille, six years after the JILO in 2014 and 31 years after the first CILO (Congrès International de Limnologie-Océanographie), the former name. This fifth edition of the JILO in Marseilles in 2020 is part of this long history of exchanges between water scientists and, given the importance of societal impacts, by associating human sciences and environmental lawyers. The IRD (Institut de Recherche pour le Développement) is fully involved in the organisation of JILO 2020. The University of Aix-Marseille will be your host this year in 2020 for the International Limnology and Oceanography Days, which will be held on its premises in the Jardin du Pharo.