On-board Diary: Mountains under the sea

Author: Silvia García
Date: August 7, 2011



We returned to Alboran after three good days of working on Gorringe and roughly one and a half days sailing. We’re going to document another one of the many seamounts in this area, one that we barely know anything about. Afterwards, we’ll return to Seco de los Olivos for some more diving before the end of this campaign.

Today, we’re going to do two dives, one on the northern peak and another on the sourthern peak, at depths between 300 and 500 meters. The first peak is covered in sea fans and deep-sea sponges, all very well anchored on top of the remnants of an old coral reef. Even dead, these reefs still form complex habitats, comprised of a wide variety of species.

The second dive takes us to a muddier peak, but also with remnants of what used to be a live coral reef. We make a transect combining sections of muddy sea beds and their associated species, including polychaete worms, some cnidarians and crustaceans, with sections of the dead reef. These last are also very characteristic because certain deep-sea sponges settle here, more so than on the reef itself or directly on the mud. During this last dive, we took a few samples of the sea fans for identification, and this will help us describe these deep-sea habitats better, thus improving their conservation.