Medium and long-term observation of the evolution of the marine environment through the acquisition and study of "long-term series" is clearly recognized as a necessity for understanding how ecosystems react to both natural and anthropogenic environmental constraints. This is obviously the case for coastal areas (lagoons, bays, estuaries, etc.), which are particularly vulnerable due to the increasing pressure of human activities in these areas which are, moreover, the subject of numerous conflicts of use. The “Service d'Observation en Milieu Littoral” (SOMLIT) was created in 1995, then accredited in 1996 by the national CNRS institute INSU (Ocean-Atmosphere domain), giving it the status of “Service National d’Observation” (SNO). The first databases appeared in January 1997. Since that date, SOMLIT has continued to develop in order to meet scientific requirements and the need for re-labelling every 4 years. Today in 2024, SOMLIT monitors 12 different ecosystems on a weekly basis (for most of them) on the 3 facades of mainland France. This represents 20 monitoring points on which vertical profiles are carried out using multiparametric probes and are measured on the surface and at the bottom, 16 basic parameters, all representing 400 time series on a national scale. The SOLA station (buoy) is one of the pioneers of this network. It constitutes the historic observation station of the Banyuls sur Mer Observatory and is managed today by the BOSS (Banyuls Observation Sea Service). The buoy is located in Banyuls Bay at a distance of 0.5 nautical miles offshore from the marine station. It serves as a sampling site for low-frequency monitoring of SOMLIT and PHYTOBS networks and is equipped with an AIRMAR 200WX meteorological station and a YSI EXO3 multiparameter CTD probe placed 1.5m below the surface. The data averaged over 1 min (SR=1s) are sent to a server on land and integrated into a local database, allowing it to be distributed to national and international databases.