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| Titel |
European Cold-Water Corals: Hydrography and Geochemistry. What is the message? |
| VerfasserIn |
W.-C. Dullo  , A. Rüggeberg, S. Flögel |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024384
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| Zusammenfassung |
| Cold-water corals are known to be abundant in the world’s oceans forming unique reef
structures mainly built up by colonial azooxanthellate scleractinians Lophelia pertusa and
Madrepora oculata. Focusing on the European continental margin, these cold-water coral
reefs occur on moraine ridges off Norway to small coral topped mounds and huge coral banks
in the Rockall Trough, the Porcupine Seabight, the Gulf of Cadiz, but only have a patchy
occurrence in the Mediterranean Sea.
Living cold-water coral reefs occur over a wide bathymetric and hydrographical range.
We found that cold-water coral reefs are limited to different intermediate water masses.
Measurements of the physical and geological properties showed that parameters such as
temperature, salinity, dissolved oxygen content, current intensities, and different 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 corals of 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 the ambient seawater from which the coral precipitates. The correlation of
established proxies such as δ18O and δ13C with temperature is possible as well, however,
it remains difficult since there is no direct temperature equation applicable as in
shallow-water corals. Other temperature proxies such as Sr/Ca, Mg/Ca and U/Ca
are in?uenced by the complex microstructure of the aragonite skeleton, the rate of
calci?cation, and other vital effects observed for coral species. We will present a variety of
established and new proxies and will discuss their application and interpretation potential. |
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