These were monthly survey cruises on the mooring site with a dual objective of (1) verifying the buoy's good operability and the good condition of the mooring and (2) carrying out a series of additional measurements that are needed either to interpret the continuous measurements taken on the mooring or to acquire additional parameters for marine optics studies. The supplementary measurements include: CTD profiles, HPLC pigments, specific absorption of phytoplankton, particles and dissolved matter, dry weight, descending and ascending underwater radiance profiles, inherent optical property profiles, atmospheric measurements (aerosols), reflectance measurements above the surface and using a fluorimeter to grid the area. The BOUSSOLE site (43°22' N, 7°54' E) is close to the DYFAMED site. It is located in the zone declared to the Maritime authorities as an area where scientific studies are run and scientific instruments moored (indicated on sea charts). BOUSSOLE 2013 trips aboard RV TETHYS took place on 21, 22, 24 and 25/01, from 12 to 16/02, from 13 to 16/03, from 10 to 14/04, from 15 to 18/05, from 08 to 10/06, on 12, 13 and 15/07, on 23, 24 and 27/08, on 10, 12 and 13/09, from 19 to 22/10, on 14, 15, 16 and 18/11 and from 11 to 14/12, but they were combined with those of MOOSE (DYFAMED) (13450020) and MOOSE (ANTARES) (13450030). The related project is called Mediterranean Oceanic Observing System on Environment (MOOSE).