Paleoseawater density reconstruction and its implication for cold-water coral carbonate mounds in the northeast Atlantic through time.

Rüggeberg, Andres, Flögel, Sascha, Dullo, Wolf-Christian , Raddatz, Jacek and Liebetrau, Volker (2016) Paleoseawater density reconstruction and its implication for cold-water coral carbonate mounds in the northeast Atlantic through time. Open Access Paleoceanography, 31 (3). pp. 365-379. DOI 10.1002/2015PA002859.

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Abstract

Carbonate buildups and mounds are impressive biogenic structures throughout Earth history. In the recent NE Atlantic, cold-water coral (CWC) reefs form giant carbonate mounds of up to 300 m of elevation. The expansion of these coral carbonate mounds is paced by climatic changes during the past 2.7 Myr. Environmental control on their development is directly linked to controls on its main constructors, the reef-building CWCs. Seawater density has been identified as one of the main controlling parameter of CWC growth in the NE Atlantic. One possibility is the formation of a pycnocline above the carbonate mounds, which is increasing the hydrodynamic regime, supporting elevated food supply, and possibly facilitating the distribution of coral larvae. The potential to reconstruct past seawater densities from stable oxygen isotopes of benthic foraminifera has been further developed: a regional equation gives reliable results for three different settings, peak interglacials (e.g., Holocene), peak glacials (e.g., Last Glacial Maximum), and intermediate setting (between the two extremes). Seawater densities are reconstructed for two different NE Atlantic CWC carbonate mounds in the Porcupine Seabight indicating that the development of carbonate mounds is predominantly found at a seawater density range between 27.3 and 27.7 kg m−3 (σΘ notation). Comparable to recent conditions, we interpret the reconstructed density range as a pycnocline serving as boundary layer, on which currents develop, carrying nutrition and possibly coral larvae. The close correlation of CWC reef growth with reconstructed seawater densities through the Pleistocene highlights the importance of pycnoclines and intermediate water mass dynamics.

Document Type: Article
Additional Information: WOS:000374344000002
Keywords: cold-water corals; carbonate mounds; seawater density; Pleistocene; northeast Atlantic; RV Poseidon; POS265; RV Joides Revolution; IODP Exp. 307
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2015PA002859
ISSN: 0883-8305
Projects: TRISTAN, ISOLDE, INWADE, COCARDE - ICA, COCARDE - ERN, IODP
Expeditions/Models/Experiments:
Date Deposited: 19 Apr 2016 07:18
Last Modified: 01 Feb 2019 15:02
URI: http://oceanrep.geomar.de/id/eprint/32094

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