MATERIALS AND METHODS

The research cruise was carried out with the 42 meter R/V Mariagrazia (Societa' Tonno Rosso) (fig. 2), owned by F.lli Ferdinando Gallo and Bros., operated by SO.PRO.MAR. and on lease to CNR. Ship is normally used for geological, geophysical and oceanographical work in the Mediterranean Sea.

**Figure 2:** R/V *Mariagrazia*, starboard side.
$\includegraphics[width=\linewidth]{IMG/MARIAGRAZIA_DESTRA.eps}$

R/V Mariagrazia is equipped with DGPS positioning system (satellite link by FUGRO, and Kongsberg's SEAPATH), single-beam and multibeam bathymetry and integrated geophysical and oceanographical data acquisition systems, including ADCP, CHIRP SBP and other Sonar Equipment, other than water and sediment sampling. Additional equipment can be accommodated on the keel or towed, e.g. Side Scan Sonars.

NAVIGATION, CHIRP SBP, SWATH BATHYMETRY

The vessel was set-up for data acquisition and navigation with PDS-2000 software by RESON, interfacing by a multiserial and Ethernet link several instruments, among them the SEAPATH (Kongsberg) and DGPS (Fugro), the Kongsberg EA-600 echosunder, the MRU and the AANDERAA meteorological station. A Kongsberg processor running the SIS software, collected the multibeam data, including a SEAPATH MRU, compass, and DGPS. The MBES was the 300kHz, 400 1x2° beams, 150° aperture, dual head EM-3002-D (200 m range) model by Kongsberg. The sonar head is positioned on the ship's keel using a V-shaped steel frame. A Sound Velocity probe at the keel 1m above the Sonar Head is interfaced directly to the MBES processor, thus providing the necessary real-time data for the beam-forming. CTD casts were normally used for input of the sound velocity profile to the system. An Anderaa Meteorological Station was also made available, at a rate of one measurement every 10-15 s.

CTD

CTD data were obtained by a Sea Bird SBE 911 probe. Table 7 in the appendix shows the position of the stations. Hydrological measurements included CTD vertical profiles (pressure, temperature, conductivity, dissolved oxygen), acquired by the SeaBird SEASAVE software. Among the many parameters, T, S, Pressure were used to provide to the MBES the necessary water column speed of sound profile. Data were extracted from the 0.25 or 0.5 m averaged profiles, and input on the MBES console. A procedure was set up in order to ease the handling of the procedure, in particular for the extension of data to the depth of 12000m, as required by the SIS Kongsberg's software.

BOTTOM SAMPLING

Bottom sampling was performed by Van-Veen grab. Table 2 shows the position of samples, that were subsampled and preserved on fridge and freezer.

MAPPING AND MISCELLANEOUS

The datum was set to WGS84 and the UTM, zone 33N projection, was chosen for navigation, display, and data acquisition. The time zone was set to the UTC for the instrumental data acquisition.

The positioning maps and bathymetric images were produced with GMT [Wessel & Smith(1998)].

The multibeam data were pre processed on board by the MB-SYSTEM MBSYSTEM2009 and GMT software and ISMAR's routines and scripts, using the SIS production DTMS or raw .all file.

Table 1: SEAPATH offsets during cruise LTES1-10 R/V Mariagrazia. Z positive downwards.

POSITION	ACROSS	ALONG	HEIGHT
REFERENCE	0.00	0.00	0.00
SEAPATH	-4.039	0.163	-18.211
MRU	-0.341	-1.342	-1.596
MBEAM TX	0.0936	10.2964	5.0623
MBEAM RX	-0.0031	11.0144	5.0600
SEALEVEL	0	0	-0.0875
MAGNETOM.	2.0	-145.0	0.0
CHIRP	1.5	7.0	2.0
STERN	4.0	-10.0	0.0
CORER	-8.0	8.0	0.0

Table 2: Samples on cruise LTES1-10. BC=box-corer, G=grab. Latitude and Longitude expressed as ddmm.xx

lon lat depth	sample	date	where
1234.312 4408.580 10.5	G01	2010-06-02	E1

**Figure 3:** Cruise LTES1-10: shaded relief bathymetry obtained by 4 multibeam runlines SE of Bocche di Lido (Venice), *sand waves* area. Superimposed contour lines are from 1990 and 1991 R/V *Bannock* cruises (single beam data)
$\includegraphics[width=\linewidth]{IMG/LTES1-10_SW.eps}$ .