Preliminary results: water column

The aim of the cruise was chiefly geological-geophysical; thus the main purpose of oceanographic. measurements was that of updating and correcting sound velocity for MB acquisition. CTD casts were collected with a SeaBird probe each 24 hours in the 0-2500m depth range. However, several anomalies with respect to modelled temperature/salinity profiles in this region of the North Atlantic mainly due to the influence of Mediterranean Water in the form of Meddies (Mediterranean eddies) were detected. The Meddies are coherent structures of warm and salt Mediterranean Water advected in the northeast Atlantic. Their thermo-haline properties are in the average 11.8°C, 36 psu with a radius between 25 and 110 km, and thickness between 500 and 1000 (see ref.). In almost all the water measurements such Meddies were detected in the proximity of Ampére , and Unicorn smts. at depths between 700 and 1300 m. Due to the lost of the CTD probe at the end of the 1st leg the remaining water measurements were done with the spare SVP probe usable only down to 1000 m depths. For this reason, no deep data over Seine smt was obtained nor the potential evidence for the existence of Meddies in this area. The physical sensors installed under the ship hull allowed the continual measurement, with a sampling frequency of 5 minutes, of the surface water temperature and salinity. The mean sea-water temperature was around 21.5°C in the Atlantic (starting from 23.5 °C in the Mediterranean). Crossing the Gibraltar Strait, the water temperature decreased to 16-17 °C. A 2°C decrease was also detected at the passage of Bonifacio Strait (between Sardinia and Corsica).

**Figure 33:** CTD cast n.1, Ampéresmt, 10-24-2005. Temperature and salinity departures from standard profile between 700 and 1200 m suggest occurrence of Mediterranean waters eddy.
$\begin{figure}\centerline{\epsfig{ file=IMG/a_ctd_01.ps,width=12.5cm}} \end{figure}$

**Figure 34:** CTD cast n.2, Ampéresmt, 10-24-2005. Comments as in fig.33
$\begin{figure}\centerline{\epsfig{ file=IMG/a_ctd_02.ps,width=12.5cm}} \end{figure}$

**Figure 35:** CTD cast n.3, Ampéresmt, 10-24-2005. Data were acquired only until 80 m just on top of the seamount.
$\begin{figure}\centerline{\epsfig{ file=IMG/a_ctd_03.ps,width=12.5cm}} \end{figure}$

**Figure 36:** Unicorn smt, CTD cast 4, 10-27-2005. Also here the occurrence of a Meddy seems confirmed by data.
$\begin{figure}\centerline{\epsfig{ file=IMG/u_ctd_04.ps,width=12.5cm}} \end{figure}$

**Figure 37:** Unicorn smt, CTD cast 5, 10-27-2005. Also here the occurrence of a Meddy seems confirmed by data.
$\begin{figure}\centerline{\epsfig{ file=IMG/u_ctd_05.ps,width=12.5cm}} \end{figure}$

**Figure 38:** Seine smt SVP 1 (n 6 in sequential order), 11-06-2005. Water column during the 2nd leg was explored until 1000 m with the SVP probe due to the lost of the CTD rosette.
$\begin{figure}\centerline{\epsfig{ file=IMG/s_svp_01.ps,width=12.5cm}} \end{figure}$

**Figure 39:** Seine smt, SVP 2 (n 7 in sequential order), 11-06-2005. Comments as in previous figures.
$\begin{figure}\centerline{\epsfig{ file=IMG/s_svp_02.ps,width=12.5cm}} \end{figure}$

**Figure 40:** Seine smt, SVP 3 (n 8 in sequential order), 11-06-2005. Comments as in previous figures.
$\begin{figure}\centerline{\epsfig{ file=IMG/s_svp_03.ps,width=12.5cm}} \end{figure}$

**Figure 41:** Unicorn smt, SVP 1 (n 9 in sequential order), 11-06-2005. Comments as in previous figures.
$\begin{figure}\centerline{\epsfig{ file=IMG/u_svp_01.ps,width=12.5cm}} \end{figure}$

**Figure 42:** Surface sea-water parameters (temperature) while cruising. Note the lows at Gibraltar and Bonifacio straits (arrows).
$\begin{figure}\centerline{\epsfig{ file=IMG/water_temp.eps,width=12.5cm}} \end{figure}$

**Figure 43:** Surface sea-water parameters (conductivity) while cruising. Note the lows at Gibraltar and Bonifacio straits (arrows).
$\begin{figure}\centerline{\epsfig{ file=IMG/water_cond.eps,width=12.5cm}} \end{figure}$