“Warm-water coral reefs are so eye-catching and visible—the Great Barrier Reef is said to be the only organic structure on the planet that can be seen from outer space—that we tend to forget that there are coral reefs of a very different kind in deeper and colder waters. The featured paper in this issue of Limnology & Oceanography draws our attention to these structures and presents vital clues as to how the many mouths of a deep-water coral community in the North Atlantic Ocean, dominated by the colonial scleractinian Lophelia pertusa, are maintained and fed.”

So said Professor Tony Larkum, Associate Editor of Limnology and Oceanography, in a review of recent work carried out by researchers from SAMS and the Royal Netherlands Institute for Sea Research.

As part of a European project investigating Hot-spot ecosystems throughout Europe (HERMES), SAMS scientists Andrew Davies and J. Murray Roberts joined researchers from the Royal Netherlands Institute for Sea Research (NIOZ). During 2006 and 2007, they jointly conducted an in-depth investigation into the hydrodynamics of Scotland’s only inshore cold-water coral reef. Lying approximately 13 km from the Outer Hebridean Island of Mingulay, this site contains large coral reefs formed by the coral Lophelia pertusa.

Little is known about how these reefs are fuelled with food, and this study represents a tantalising glimpse into the interplay between the physical habitat and the corals themselves. To achieve this they used an array of equipment including current meters and specialised benthic landers (pictured) to resolve two distinct and predictable supply mechanisms. The reefs were found to be subjected to a tidally driven downwelling of surface water, that brings both food and warmer waters from the surface. The second mechanism consisted of particles delivered horizontally by water flow. These findings have been published in the journal Limnology and Oceanography.

Davies, Andrew J., Gerard Duineveld, Marc Lavaleye, Magda J. Bergman, Hans van Haren, and J. Murray Roberts. 2009. Downwelling and deep-water bottom currents as food supply mechanisms to the cold-water coral Lophelia pertusa (Scleractinia) at the Mingulay Reef Complex. Limnol. Oceanogr. 54(2): 620–629.

HERMES: www.eu-hermes.net

NIOZ www.nioz.nl