Coral Paradise in the deep, dark and cool waters west of Ireland

On Friday, June 20th 2003, the German research ice-breaker POLARSTERN of the Alfred-Wegener-Institute (AWI) for Polar and Marine Research in Bremerhaven/ Germany will visit the port of Galway/ Ireland, after a 3-week international expedition to study the deep-water coral reefs to the west of Ireland. Over 40 scientists working on a variety of European-funded research projects and from marine institutes in Ireland, Belgium, the UK, France and Germany are participating in the expedition. They will depart the ship to return to their home institutes in Galway, before POLARSTERN (managed by the German shipping company F. LAEISZ in Hamburg/ Rostock/ Bremerhaven) departs for the next leg of its 2003 summer expedition to the Arctic Ocean. A special feature of the first leg, now about to finish in Galway, was the combination for the first time in Irish waters, of the POLARSTERN research vessel, a modern, efficient, large and very stable (with its 11m draft), bad weather tolerant mothership with the world's most modern deep-sea robot (ROV), the VICTOR 6000 of Ifremer (Institut Francaise de Recherche pout l´Exploitation de la Mer). VICTOR is an unmanned deep-sea robot that can dive to 6000 m water depth, with a weight of 4 tons and with remotely operated cameras and manipulators that allow the collection of in-situ samples and data with unprecedented precision.

Under the framework of this international expedition, scientists have been able to complete a comprehensive, intensive and complex study program on Irish coral locations using the ROV. A feature of the first two weeks was the unseasonable bad weather that would have seriously curtailed the dive programme on a smaller ship. The Polarstern proved more than capable permitting a series of dives with VICTOR to take place. Collectively more than 100 hours of high resolution video have been shot on the seafloor and many samples collected over more than 100 km2 of seafloor. Between dives systematic surveys have been conducted by means of grabs, multicorer (precision sediment sampler), CTD (water profiler) and ship borne sonar systems mounted on the POLARSTERN. This expedition began in Brest/ France on June 2nd, 2003 where more than 100 tons of VICTOR equipment was installed. This is the second time VICTOR has been deployed from the POLARSTERN and the third time it has been used by international working groups under the framework of closer and more formal French-German cooperation in polar and marine sciences. The Irish participants of this expedition come from marine research institutes in the Universities of Cork, Dublin and Galway and the Geological Survey of Ireland. A number of the Irish participants are veterans of the IFREMER lead VICTOR campaign studying Irish deep-water corals in 2001 and their expertise was invaluable during the current expedition.

The North-East Atlantic to the west of Ireland, not only harbours rich fishing grounds, but is also a treasure chest for new ocean discoveries. Several hundred meter high submarine carbonate mounds topped with coral reefs are part of these largely unexplored treasures. They occur in a narrow depth range between 500 and 1000 m water depth along a belt trailing the entire west European continenal margin, from the Bay of Biscay to the Barents Sea in the Arctic. . Deepwater corals were already known to Irish, English and Norwegian fishermen as well marine biologists over a 100 years ago as they were repeatedly taken in their catches. Lophelia pertusa, the major framework constructing coral of these habitats, has adapted to the cold, deep and dark living conditions found at these depths off the west coast of Ireland. A unique feature of Irish corals is their contribution to the growth of carbonate mound 'bioherms' - underwater hills up to 300m in height composed of coral skeletons and sediments. These mounds occur in high numbers along the margins of the Irish Porcupine Seabight and Porcupine Bank. Scientists have estimated that approx. 60% of the European deep-water coral occurrences are located off Ireland.

Modern geophysical surveys detected these large structures under the surface of the seafloor and helped to define the geometry of the mound-like structures that have been frequently found deeply buried under a sediment cover. They form extensive sediment bodies and structures with high porosities at great depth and they are therefore of interest not only for the academic scientists, but also for the hydrocarbon industry hunting for potential reservoirs in the deep ocean.

Coral reefs are typical for tropical ocean regions where they assemble rich communities of benthic organisms just below the sea surface and where they are under the influence of sunlight develop a high biological activity and fast turnover of nutrients. How and when reefs developed in the cool, deep and dark bottom waters over the Porcupine Seabight and Porcupine Bank and how they exist there under modern conditions is not fully resolved. Their origin can be found in fossils preserved in relatively old geological deposits. Did the Irish carbonate mounds also originate several million years ago and have they been growing ever since? From where do they receive their nutrition, from cold nutrient-rich seeps from deep underground, or from accumulations of suspended material which can be clearly observed in well defined layers throughout the oceanic water column? Why are they found limited to well-defined structures in certain depth intervals and why do they not occur everywhere? Which organisms contribute to the construction of the reefs and what is their role in this process? Are all carbonate mounds the same or should they be viewed as differing entities? Is the coral paradise of the Porcupine Seabight and Porcupine Bank endangered and harmed by bottom trawling fisheries? Do Irish deep-water corals need protecting and are they of European importance as outstanding examples of the deep-water coral habitat?

These and other questions will be dealt with during a press conference on June 20th, 2003 10.00-11.00 am hrs. onboard POLARSTERN on anchorage off Galway (transport to and from the ship will be organized). The chief scientist of the first part of the expedition, Prof. Dr. Jörn Thiede (AWI), the chief scientist of the next leg from Galway to Tromsö/ Norway, Dr. Michael Klages (AWI), the captain of POLARSTERN Mr. Udo Domke and senior Irish, French and German members of the expedition team will be available to answer questions. Photographic materials and high resolution video highlights will be available on request.

Additional information, pictures and short movie clips about this expedition are accessible through the Internet under www.polarstern-victor.de.