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Solenosmilia variabilis-bearing cold-water coral mounds off Brazil

(2020) CORAL REEFS. 39(1). p.69-83
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Abstract
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 Th-230/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.
Keywords
DEEP-SEA CORALS, LOPHELIA-PERTUSA SCLERACTINIA, EASTERN NORTH-ATLANTIC, CARBONATE-MOUND, WESTERN BOUNDARY, ROCKALL TROUGH, PACIFIC-OCEAN, FUGLOY, REEF, NE ATLANTIC, ICE-CORE, Cold-water corals, South Atlantic, Th-230, U, Computed tomography

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MLA
Raddatz, J., et al. “Solenosmilia Variabilis-Bearing Cold-Water Coral Mounds off Brazil.” CORAL REEFS, vol. 39, no. 1, Springer, 2020, pp. 69–83, doi:10.1007/s00338-019-01882-w.
APA
Raddatz, J., Titschack, J., Frank, N., Freiwald, A., Conforti, A., Osborne, A., … Bahr, A. (2020). Solenosmilia variabilis-bearing cold-water coral mounds off Brazil. CORAL REEFS, 39(1), 69–83. https://doi.org/10.1007/s00338-019-01882-w
Chicago author-date
Raddatz, J., J. Titschack, N. Frank, A. Freiwald, A. Conforti, A. Osborne, S. Skornitzke, et al. 2020. “Solenosmilia Variabilis-Bearing Cold-Water Coral Mounds off Brazil.” CORAL REEFS 39 (1): 69–83. https://doi.org/10.1007/s00338-019-01882-w.
Chicago author-date (all authors)
Raddatz, J., J. Titschack, N. Frank, A. Freiwald, A. Conforti, A. Osborne, S. Skornitzke, W. Stiller, A. Rueggeberg, S. Voigt, A. L. S. Albuquerque, Agostina Vertino, A. Schroeder-Ritzrau, and A. Bahr. 2020. “Solenosmilia Variabilis-Bearing Cold-Water Coral Mounds off Brazil.” CORAL REEFS 39 (1): 69–83. doi:10.1007/s00338-019-01882-w.
Vancouver
1.
Raddatz J, Titschack J, Frank N, Freiwald A, Conforti A, Osborne A, et al. Solenosmilia variabilis-bearing cold-water coral mounds off Brazil. CORAL REEFS. 2020;39(1):69–83.
IEEE
[1]
J. Raddatz et al., “Solenosmilia variabilis-bearing cold-water coral mounds off Brazil,” CORAL REEFS, vol. 39, no. 1, pp. 69–83, 2020.
@article{8688129,
  abstract     = {{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 Th-230/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.}},
  author       = {{Raddatz, J. and Titschack, J. and Frank, N. and Freiwald, A. and Conforti, A. and Osborne, A. and Skornitzke, S. and Stiller, W. and Rueggeberg, A. and Voigt, S. and Albuquerque, A. L. S. and Vertino, Agostina and Schroeder-Ritzrau, A. and Bahr, A.}},
  issn         = {{0722-4028}},
  journal      = {{CORAL REEFS}},
  keywords     = {{DEEP-SEA CORALS,LOPHELIA-PERTUSA SCLERACTINIA,EASTERN NORTH-ATLANTIC,CARBONATE-MOUND,WESTERN BOUNDARY,ROCKALL TROUGH,PACIFIC-OCEAN,FUGLOY,REEF,NE ATLANTIC,ICE-CORE,Cold-water corals,South Atlantic,Th-230,U,Computed tomography}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{69--83}},
  publisher    = {{Springer}},
  title        = {{Solenosmilia variabilis-bearing cold-water coral mounds off Brazil}},
  url          = {{http://dx.doi.org/10.1007/s00338-019-01882-w}},
  volume       = {{39}},
  year         = {{2020}},
}

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