Corals, sea-feathers and sponges at the cold-water coral reef. Photo: NIOZ.

Cold-water corals have small tentacles that they use to trap small food particles from the water. We are here to find out how these particles end up at hundreds of meters below the surface. It seems that they don't only sink down. Computer simulations of the dynamics of the water in the area suggest that the tide plays an important role in the transport of food particles towards the bottom. Therefore, we placed two moorings, a line with instruments moored to the bottom with a 600 kg weight, to measure currents and food particles during a whole year. An important objective for this year is to retrieve these instruments, but that is not all.

We set out from Galway to take detailed measurements of the distribution of food particles during a full tidal cycle, at several stations. After two weeks, this should give a full bag of data that will keep us busy for the next year and hopefully teach us a bit more about where the cold-water corals at Rockall Bank get their food from.

Dick van Oevelen, chief-scientist & Anna van der Kaaden, PhD-candidate (NIOZ)