Environmental constraints on Holocene cold‐water coral reef growth off Norway: Insights from a multiproxy approach
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Raddatz, Jacek
Goethe University Frankfurt, Institute of Geosciences, Frankfurt am Main, Germany - GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
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Liebetrau, Volker
GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
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Trotter, Julie
The UWA Oceans Institute and School of Earth and Environment, University of Western Australia, Crawley, Australia
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Rüggeberg, Andres
Renard Centre of Marine Geology, Department of Geology and Soil Sciences, Ghent University, Belgium - Department of Geosciences, University of Fribourg, Switzerland
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Flögel, Sascha
GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
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Dullo, Wolf-Christian
GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
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Eisenhauer, Anton
GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
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Voigt, Silke
Goethe University Frankfurt, Institute of Geosciences, Frankfurt am Main, Germany
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McCulloch, Malcolm
The UWA Oceans Institute and School of Earth and Environment, University of Western Australia, Crawley, Australia - ARC Centre of Excellence in Coral Reef Studies, University of Western Australia, Crawley, Australia
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Published in:
- Paleoceanography. - 2016, vol. 31, no. 10, p. 1350–1367
English
High-latitude cold-water coral (CWC) reefs are particularly susceptible due to enhanced CO₂ uptake in these regions. Using precisely dated (U/Th) CWCs (Lophelia pertusa) retrieved during research cruise POS 391 (Lopphavet 70.6°N, Oslofjord 59°N) we applied boron isotopes (δ¹¹B), Ba/Ca, Li/Mg, and U/Ca ratios to reconstruct the environmental boundary conditions of CWC reef growth. The sedimentary record from these CWC reefs reveals a lack of corals between ~6.4 and 4.8 ka. The question remains if this phenomenon is related to changes in the carbonate system or other causes. The initial postglacial setting had elevated Ba/Ca ratios, indicative of meltwater fluxes showing a decreasing trend toward cessation at 6.4 ka with an oscillation pattern similar to continental glacier fluctuations. Downcore U/Ca ratios reveal an increasing trend, which is outside the range of modern U/Ca variability in L. pertusa, suggesting changes of seawater pH near 6.4 ka. The reconstructed bottom water temperature at Lopphavet reveals a striking similarity to Barent sea surface and subsea surface temperature records. We infer that meltwater pulses weakened the North Atlantic Current system, resulting in southward advances of cold and CO₂-rich Arctic waters. A corresponding shift in the δ¹¹B record from ~25.0‰ to ~27.0‰ probably implies enhanced pH up-regulation of the CWCs due to the higher pCO₂ concentrations of ambient seawater, which hastened mid-Holocene CWC reef decline on the Norwegian margin.
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Faculty
- Faculté des sciences et de médecine
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Department
- Département de Géosciences
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Language
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Classification
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Ecology and biodeversity
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License
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License undefined
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Identifiers
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Persistent URL
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https://folia.unifr.ch/unifr/documents/305505
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