On-board Diary: Channel of Mallorca
Author: Xavier Pastor
Date: September 22, 2007
Last night, we set sail from Palma and headed towards the seamounts of the channel of Mallorca. We had to make some adjustments because we wanted to reach 300 meters depth, and we had to wait until the weather improved. As soon as we were ready, we headed towards the first and deepest seamount, Les Olives.
Although the sea was quite calm, the morning was cloudy. The clouds do not only appear in the sky, though. They also appear on the robot, with which we are having some difficulties.
As soon as we reach our destination, we scan the area in order to profile the seamount. We thought its top was more circular in shape, but it is actually quite sharp on the south-eastern side and we spot some of the surface points there; between 215 and 230 meters. We decide, however, to concentrate on the north-eastern side, where there are also some rocky areas.
At last, we're ready to return to the water. The ROV descends as it encounters diverse zooplankton. Ctenophores, hydrozoans, salps, what looks like pteropod molluscs, etc. And just above the sea bed, a multitude of tiny, disc-shaped organisms. But we can hardly see much else; the current is very strong and makes it difficult to manoeuvre the robot. To top it off, we start having more problems and must cancel the dive and hoist the robot to see what’s wrong.
While we are doing this, a manta ray (Mobula sp.) approaches the boat. It swims around us various times, shows us its belly and, after a few minutes of investigation, continues on its way.
The ROV’s problems are not easily solved so we decide to set sail towards Formentera. We have to think about what we’re going to do if things don’t work out.