Dullo, Wolf-Christian

Flögel, Sascha

Rüggeberg, Andres

English

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Geophysical Research Abstracts,Vol. 11, EGU2009-6053, 2009EGU General Assembly 2009© Author(s) 2009European Cold-Water Corals: Hydrography and Geochemistry. What isthe message?W.-C. Dullo, A. Rüggeberg, and S FlögelIFM-GEOMAR, Leibniz-Institute for Marine Science, Kiel, Germany (cdullo@ifm-geomar.de, + 49 431 6002925)Cold-water corals are known to be abundant in the world’s oceans forming unique reef structures mainly built upby colonial azooxanthellate scleractinians Lophelia pertusa and Madrepora oculata. Focusing on the Europeancontinental margin, these cold-water coral reefs occur on moraine ridges off Norway to small coral topped moundsand huge coral banks in the Rockall Trough, the Porcupine Seabight, the Gulf of Cadiz, but only have a patchyoccurrence in the Mediterranean Sea.Living cold-water coral reefs occur over a wide bathymetric and hydrographical range. We found that cold-watercoral reefs are limited to different intermediate water masses. Measurements of the physical and geological prop-erties showed that parameters such as temperature, salinity, dissolved oxygen content, current intensities, anddifferent substrates vary widely without specifically impacting the distribution of living cold-water coral reefs.The habitat of living reefs along the Atlantic European continental margin comprises a temperature-salinity field,with its lower boundary equivalent to the Intermediate Salinity Maximum (ISM). Therefore, cold-water coralsof these reefs may report environmental changes, present and past, if the proper geochemical tools are applied.Sr-isotopes seem to be a very promising proxy, since they portray very well the temperature conditions of theambient seawater from which the coral precipitates. The correlation of established proxies such as δ18O and δ13Cwith temperature is possible as well, however, it remains difficult since there is no direct temperature equationapplicable as in shallow-water corals. Other temperature proxies such as Sr/Ca, Mg/Ca and U/Ca are in?uencedby the complex microstructure of the aragonite skeleton, the rate of calci?cation, and other vital effects observedfor coral species. We will present a variety of established and new proxies and will discuss their application andinterpretation potential.

European cold-water corals: hydrography and geochemistry. What is the message?

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