Deep sediment resuspension and thick nepheloid layer generation by open-ocean convection

Type Article
Date 2017-03
Language English
Author(s) Durrieu De Madron Xavier1, Ramondenc S.2, Berline L.3, Houpert L.4, Bosse Anthony5, Martini S.6, Guidi L.2, Conan P.7, Curtil C.8, Delsaut N.1, Kunesch S.1, Ghiglione J. F.7, Marsaleix P.8, Pujo-Pay M.7, Severin T.9, 10, Testor P.5, Tamburini C.3
Affiliation(s) 1 : Univ Perpignan Via Domitia, CNRS, CEFREM, Perpignan, France.
2 : UPMC Univ Paris 06, Sorbonne Univ, Observ Oceanol, CNRS,LOV, Villefranche Sur Mer, France.
3 : Univ Aix Marseille, CNRS, IRD, UMR 7294,IRD 235,MIO, Marseille, France.
4 : Scottish Marine Inst, SAMS, Oban, Argyll, Scotland.
5 : UPMC Univ Paris 06, Sorbonne Univ, Lab Oceanog & Climatol, CNRS,IRD,MNHN,UMR 7159,IPSL, Paris, France.
6 : Monterey Bay Aquarium Res Inst, Moss Landing, CA USA.
7 : UPMC Univ Paris 06, Sorbonne Univ, Lab Oceanog Microbienne, Observ Oceanol,UMR 7621, Banyuls Sur Mer, France.
8 : CNRS, CPPM, Marseille, France.
9 : Univ Toulouse, CNRS, UPS, Lab Aerol, Toulouse, France.
10 : Univ Texas Austin, Inst Marine Sci, Port Aransas, TX USA.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2017-03 , Vol. 122 , N. 3 , P. 2291-2318
DOI 10.1002/2016JC012062
WOS© Times Cited 51
Abstract The Gulf of Lions in the northwestern Mediterranean is one of the few sites around the world ocean exhibiting deep open-ocean convection. Based on 6-year long (2009-2015) time series from a mooring in the convection region, shipborne measurements from repeated cruises, from 2012 to 2015, and glider measurements, we report evidence of bottom thick nepheloid layer formation, which is coincident with deep sediment resuspension induced by bottom-reaching convection events. This bottom nepheloid layer, which presents a maximum thickness of around 2000 m in the center of the convection region, probably results from the action of cyclonic eddies that are formed during the convection period and can persist within their core while they travel through the basin. The residence time of this bottom nepheloid layer appears to be less than a year. In-situ measurements of suspended particle size further indicate that the bottom nepheloid layer is primarily composed of aggregates between 100 and 1000 µm in diameter, probably constituted of fine silts. Bottom-reaching open ocean convection, as well as deep dense shelf water cascading that occurred concurrently some years, lead to recurring deep sediments resuspension episodes. They are key mechanisms that control the concentration and characteristics of the suspended particulate matter in the basin, and in turn affect the bathypelagic biological activity.
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Durrieu De Madron Xavier, Ramondenc S., Berline L., Houpert L., Bosse Anthony, Martini S., Guidi L., Conan P., Curtil C., Delsaut N., Kunesch S., Ghiglione J. F., Marsaleix P., Pujo-Pay M., Severin T., Testor P., Tamburini C. (2017). Deep sediment resuspension and thick nepheloid layer generation by open-ocean convection. Journal Of Geophysical Research-oceans, 122(3), 2291-2318. Publisher's official version : , Open Access version :