Cold water corals and carbonate mounds

Atlantic Coral Ecosystem Study (ACES) and Environmental Controls on Mound Formation Along the European Margin (ECOMOUND)

Coral reefs are usually associated with warm, tropical waters and exotic fish, but not with the cold, deep and dark waters of the North Atlantic where corals were regarded as oddities on the seafloor. It is now known that cold-water coral species also produce reefs, which may rival their tropical cousins in terms of the species richness of associated marine life. Increasing commercial operations in deep waters, and the use of advanced offshore technology have slowly revealed the true extent of Europe's hidden coral ecosystems. The discovery of extraordinary, 10 km-long chains of the reef-building corals Lophelia pertusa and Madrepora oculata in several hundred metres of water on the Norwegian and Irish Shelves have deeply challenged conventional views. The same coral assemblages are also found associated with large seabed structures in the Porcupine Seabight (offshore Ireland), where they are so abundant that their skeletal remains have, over the millennia, contributed to carbonate mound structures up to 300m high in 700-1200m water depths. The potential of cold-water corals to contribute to the formation of these large seafloor features and their high biological diversity have attracted considerable public attention through reports in numerous national TV and newspaper features.

Cold water coral sites of the British/Irish Margin

The aim of the Atlantic coral ecosystem study (ACES) was a margin-wide environmental baseline assessment of the status of Europe's deep-water coral margin to provide recommendations for essential monitoring and methodology requirements for future sustainable development. Here is some more information on the ACES project.

The major objective of its sister ECOMOUND project was to define the environmental controls and processes involved in the development and distribution of carbonate mounds on the NW European continental margin.

The OBG at Liverpool was particularly concerned with the detailed characterisation of suspended particulate organic material (sPOM) in the benthic boundary layer (BBL; an oceanic region that includes the surficial sediments of the deep-sea floor and up to 100 m of the overlying water). Its importance to coral nutrition and feeding is key to understanding the function of the whole deep-water coral ecosystem and its relationship to the mounds. In order to assess this we sampled particulate organic matter (POM) in the water column directly above and around the coral-bearing mounds and sediments (first 6-10 cm) on and off the mounds.

Five main locations with corals and mounds were sampled along the North Western European Margin over a period of three years (2000-02). Some coral samples from the Norwegian shelf and the N. Sea that were collected by our collaborators (M.Roberts in Dunstaffnage Marine Laboratory - Oban and A.Grehan in the National University of Ireland) were also analysed.

Of these locations the Darwin Mounds are rather special and it has been proposed to designate them as the UK's first offshore Special Area of Conservation. Here are some interesting links about the Darwin Mounds:

For more information on our findings please refer to the following publications:

Currently, and after the success of ACES and ECOMOUND, cold water coral and carbonate mound research on the European Margin is being carried out within the HERMES programme.