Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes

Type Article
Date 2019-10
Language English
Author(s) Rabouille C.1, Dennielou BernardORCID2, Baudin F.3, Raimonet M.4, Droz Laurence5, Khripounoff AlexisORCID6, Martinez P.7, Mejanelle L.8, Michalopoulos P.9, Pastor Lucie6, Pruski A.8, Ragueneau Olivier4, Reyss J.-L.1, Ruffine LivioORCID2, Schnyder J.3, Stetten E.3, Taillefert M.10, Tourolle JulieORCID6, Olu KarineORCID6
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
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 3
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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Rabouille C., Dennielou Bernard, Baudin F., Raimonet M., Droz Laurence, Khripounoff Alexis, Martinez P., Mejanelle L., Michalopoulos P., Pastor Lucie, Pruski A., Ragueneau Olivier, Reyss J.-L., Ruffine Livio, Schnyder J., Stetten E., Taillefert M., Tourolle Julie, Olu Karine (2019). Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes. Quaternary Science Reviews, 222, 105854 (7p.). Publisher's official version : https://doi.org/10.1016/j.quascirev.2019.07.036 , Open Access version : https://archimer.ifremer.fr/doc/00511/62289/