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Solenosmilia variabilis-bearing cold-water coral mounds off Brazil

  • Raddatz, J. Institute of Geosciences, Goethe University Frankfurt, Germany
  • Titschack, J. MARUM - Center for Marine Environmental Sciences, University of Bremen, Germany - Marine Research Department, Senckenberg am Meer, Wilhelmshaven, Germany
  • Frank, N. Institut fuer Umweltphysik, Universita¨t Heidelberg, Germany
  • Freiwald, A. Marine Research Department, Senckenberg am Meer, Wilhelmshaven, Germany - MARUM - Center for Marine Environmental Sciences, University of Bremen, Germany
  • Conforti, A. Istituto per lo studio degli impatti Antropici e Sostenibilita in ambiente marino, Consiglio Nazionale delle Ricerche (IAS CNR), Oristano, Italy
  • Osborne, A. GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
  • Skornitzke, S. Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Germany
  • Stiller, W. Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Germany
  • Rüggeberg, Andres Department of Geosciences, University of Fribourg, Switzerland
  • Voigt, Silke Institute of Geosciences, Goethe University Frankfurt, Germany
  • Albuquerque, A. L. S. Programa de Geociencias, Universidade Federal Fluminense, Niteroi, Rio de Janeiro, Brazil
  • Vertino, A. Department of Geology, Ghent University, Belgium - Department of Earth and Environmental Sciences, University of Milano-Bicocca, Italy
  • Schröder-Ritzrau, A. Institut fuer Umweltphysik, Universita¨t Heidelberg, Germany
  • Bahr, A. Institut fu¨r Geowissenschaften, Universita¨t Heidelberg, Germany
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    01.02.2020
Published in:
  • Coral Reefs. - 2020, vol. 39, no. 1, p. 69–83
English Cold-water corals (CWC), dominantly Desmophyllum pertusum (previously Lophelia pertusa), and their mounds have been in the focus of marine research during the last two decades; however, little is known about the mound-forming capacity of other CWC species. Here, we present new 230Th/U age constraints of the relatively rarely studied framework-building CWC Solenosmilia variabilis from a mound structure off the Brazilian margin combined with computed tomography (CT) acquisition. Our results show that S. variabilis can also contribute to mound formation, but reveal coral-free intervals of hemipelagic sediment deposits, which is in contrast to most of the previously studied CWC mound structures. We demonstrate that S. variabilis only occurs in short episodes of < 4 kyr characterized by a coral content of up to 31 vol%. In particular, it is possible to identify distinct clusters of enhanced aggradation rates (AR) between 54 and 80 cm ka−1. The determined AR are close to the maximal growth rates of individual S. variabilis specimens, but are still up to one order of magnitude smaller than the AR of D. pertusum mounds. Periods of enhanced S. variabilis AR predominantly fall into glacial periods and glacial terminations that were characterized by a 60–90 m lower sea level. The formation of nearby D. pertusum mounds is also associated with the last glacial termination. We suggest that the short- term periods of coral growth and mound formation benefited from enhanced organic matter supply, either from the adjacent exposed shelf and coast and/or from enhanced sea-surface productivity. This organic matter became concentrated on a deeper water- mass boundary between South Atlantic Central Water and the Antarctic Intermediate Water and may have been distributed by a stronger hydrodynamic regime. Finally, periods of enhanced coral mound formation can also be linked to advection of nutrient-rich intermediate water masses that in turn might have (directly or indirectly) further facilitated coral growth and mound formation.
Faculty
Faculté des sciences et de médecine
Department
Département de Géosciences
Language
  • English
Classification
Geology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/308404
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