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.

<p>(<b>a</b>) Potential temperature at 500 and 1,000 m depth at the LDC mooring site and (<b>b</b>) from various water depths at the LION site, jointly with (<b>c</b>) salinity at 2,300 m depth, (<b>d</b>) horizontal current speed and (<b>e</b>) 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.</p

Links between bioluminescence, current speed and the modification of the properties of the Western Mediterranean Deep Water (WMDW).

<p>Box-and-whisker plot of median PMT counting rates (log scale) versus current speed classes for salinities higher (red) or lower (grey) than 38.479 for data recorded in (<b>a</b>) 2008, (<b>b</b>) 2009 and (<b>c</b>) between January and June 2010. The salinity threshold of 38.479 is used as a marker of the intrusion of newly formed deep water at the ANTARES site. While bioluminescence increases with current speed, it is also enhanced by the modification of WMDW (red box-plots). The top and bottom of each box-plot represent 75% (upper quartile) and 25% (lower quartile) of all values, respectively. The horizontal line is the median. The ends of the whiskers represent the 10^th and 90^th percentiles. Outliers are not represented. The statistical comparison between the two box-plots (red and grey) in each current class is given by the Kruskal-Wallis test: the observed difference between the two samples is significant beyond the 0.05 (*), the 0.01 (**) and the 0.001 (***) levels. The absence of an asterisk in some current classes indicates that the difference between the two box-plots is not significant. The number of measurements for salinity lower or higher than 38.479 is given in black or in red, respectively. Note the different scales of figures a, b and c.</p