The Urania ship is a relatively small vessel, working almost always in the Mediterranean and not particularly fit for long oceanic cruises, especially during the winter season. We thank Captain Vincenzo Lubrano Lavadera and all members of the crew for their professionalism, expertise and spirit of cooperation even during rough sea conditions which we encountered on two occasions. Luca Gasperini and Giovanni Bortoluzzi (ISMAR-CNR, Bologna, Italy) are acknowledged for their assistance for sparker acquisition (hardware and software) and web publishing. Giorgio Ruta (GeoLab srl, Naples) kindly reviewed and re-edited the text.