Environmental boundary conditions of cold-water coral mound growth over the last 3 Million years in the Porcupine Seabight, Northeast Atlantic.

Raddatz, Jacek, Rüggeberg, Andres, Liebetrau, Volker, Foubert, Anneleen, Hathorne, Ed C. , Fietzke, Jan , Eisenhauer, Anton and Dullo, Wolf-Christian (2014) Environmental boundary conditions of cold-water coral mound growth over the last 3 Million years in the Porcupine Seabight, Northeast Atlantic. Deep-Sea Research Part II-Topical Studies in Oceanography, 99 . pp. 227-236. DOI 10.1016/j.dsr2.2013.06.009.

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Abstract

IODP Expedition 307 made it for the first time possible to investigate the entire body of a cold-water coral carbonate mound. Here we provide new insights into the long-term history of Challenger Mound on the European continental margin off Ireland. This study is based on age determinations (230Th/U, 87Sr/86Sr) and geochemical signals (Mg/Li and Ba/Ca) measured in the scleractinian cold-water coral Lophelia pertusa from IODP Site 1317 in the Porcupine Seabight. The paleoceanographic reconstructions reveal that coral growth in the Porcupine Seabight was restricted to specific oceanographic conditions such as enhanced export of primary production and Bottom-Water Temperatures (BWT) between ∼8–10 °C, related to the water mass stratification of the Mediterranean Outflow Water (MOW) and Eastern North Atlantic Water (ENAW). The geochemical signals from the coral skeletons can be explained by the close interaction between cold-water coral growth, sea-surface productivity and the surrounding water masses - the boundary layer between MOW and ENAW. Enhanced sea-surface productivity and the build-up of a stable water mass stratification between ENAW and MOW caused enhanced nutrient supply at intermediate water depths and facilitated a steady mound growth between∼3.0 - 2.1 Ma. With the decrease in sea-surface productivity and related reduced export productivity the food supply was insufficient for rapid coral mound growth between∼1.7 - 1 Ma. During the late Pleistocene (over the last∼0.5 Myr) mound growth was restricted to interglacial periods. During glacials the water mass boundary between ENAW/MOW probably was below the mound summit and hence food supply was not sufficient for corals to grow.

Document Type: Article
Additional Information: WOS:000332194500023
Keywords: Cold-water corals; Challenger Mound; IODP Site 1317; Lophelia pertusa; Mg/Li; Ba/Ca; Mediterranean Outflow Water
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.dsr2.2013.06.009
ISSN: 0967-0645
Projects: ISOLDE I, ISOLDE II, TRISTAN, COCARDE - ICA, Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 18 Jul 2013 12:01
Last Modified: 18 Oct 2016 09:44
URI: http://oceanrep.geomar.de/id/eprint/21606

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