1. Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
- Author
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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, 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, and Olu, Karine
- 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.
- Published
- 2019
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