Time series of oceanographic parameters measured at the Lacaze-Duthiers Canyon (LDC) and the open-sea convection region in the Gulf of Lion (LION) from January 2008 to June 2010.

(a) Potential temperature at 500 and 1,000 m depth at the LDC mooring site and (b) from various water depths at the LION site, jointly with (c) salinity at 2,300 m depth, (d) horizontal current speed and (e) vertical current speed from various water depths at the LION site. The four levels of temperature measurements at LION presented here are a sub-set of measurement depths (see Fig. S1). Essentially stable temperatures in the deepest layers in 2008 show that open-sea convection reached only 700 m and did not modify the deep water in the study area. In contrast, strong convection events, reaching 2,300 m depth, occurred during February-March 2009 and 2010 with an abrupt cooling of the upper water column and an increase in temperature and salinity in the deep layers. A concurrent increase in current speed was also noticed in winter 2009 and 2010. The 5-month long data gap in 2009 is due to a damaging of the mooring line during the April 2009 recovery, which induced a postponement of its redeployment to September 2009.