Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
Type | Article | ||||||||||||||||
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Date | 2019-10 | ||||||||||||||||
Language | English | ||||||||||||||||
Author(s) | Rabouille C.1, Dennielou Bernard![]() ![]() ![]() ![]() ![]() |
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Affiliation(s) | 1 : Laboratoire des Sciences du Climat et de l’Environnement, UMR CEA-CNRS-UVSQ 8212 et IPSL, Université Paris-Saclay, Avenue de la Terrasse, 91190, Gif sur Yvette, France 2 : Unité de Recherche Géosciences Marines, IFREMER, 29280, Plouzané, France 3 : Institut des Sciences de la Terre de Paris, Sorbonne Université, CNRS, UMR 7193, 4 Place Jussieu, 75005, Paris, France 4 : Laboratoire des Sciences de l'Environnement Marin, UMR UBO-CNRS, Institut Universitaire Européen de la Mer, 29280, Plouzané, France 5 : Laboratoire Domaines Océaniques, UMR UBO-CNRS6538, Institut Universitaire Européen de la Mer, 29280, Plouzané, France 6 : IFREMER Centre Bretagne, Unité de Recherche Etude des Ecosystèmes Profonds, (REM-EEP-LEP), 29280, Plouzané, France 7 : Environnements et Paléoenvironnements Océaniques et Continentaux, Université de Bordeaux, UMR 5805, Allée Geoffroy St Hilaire, 33615, Pessac Cedex, France 8 : Laboratoire d’Ecogéochimie des Environnements Benthiques, Sorbonne Université, CNRS, UMR 8222, Observatoire Océanologique, 66650, Banyuls-sur-Mer, France 9 : Institute of Oceanography, Hellenic Center for Marine Research, 46.7 km Athens-Sounion An, Anavyssos, 19013, Greece 10 : School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA, 30332, USA |
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Source | Quaternary Science Reviews (0277-3791) (Elsevier BV), 2019-10 , Vol. 222 , P. 105854 (7p.) | ||||||||||||||||
DOI | 10.1016/j.quascirev.2019.07.036 | ||||||||||||||||
WOS© Times Cited | 16 | ||||||||||||||||
Keyword(s) | Present, Paleoceanography, South Atlantic, Inorganic geochemistry, Organic geochemistry, Sedimentology-marine cores | ||||||||||||||||
Abstract | Carbon and silicon cycles at the Earth surface are linked to long-term variations of atmospheric CO2 and oceanic primary production. In these cycles, the river-sea interface is considered a biogeochemical hotspot, and deltas presently receive and preserve a major fraction of riverine particles in shallow water sediments. In contrast, periods of glacial maximum lowstand were characterized by massive exports of sediments to the deep-sea via submarine canyons and accumulation in deep-sea fans. Here, we calculate present-day mass balances for organic carbon (OC) and amorphous silica (aSi) in the terminal lobe complex of the Congo River deep-sea fan as an analogue for glacial periods. We show that this lobe complex constitutes a megasink with the current accumulation of 18 and 35% of the OC and aSi river input, respectively. This increases the estimates of organic carbon burial by 19% in the South Atlantic Ocean in a zone representing less than 0.01% of the basin. These megasinks might have played a role in carbon trapping in oceanic sediments during glacial times. |
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