Modeling biogeochemical processes in sediments from the Rhone River prodelta area (NW Mediterranean Sea)

Type Article
Date 2011-05-27
Language English
Author(s) Pastor L.1, Cathalot C.2, Deflandre B.1, 3, Viollier E.1, Soetaert K.4, Meysman F. J. R.4, Ulses C.5, Metzger E., Rabouille C.2
Affiliation(s) 1 : Univ. Paris Diderot, Sorbonne Paris Cité, Institut de Physique du Globe de Paris, UMR7154 CNRS, 75013 Paris, France
2 : Lab. des Sciences du Climat et de l'Environ., CEA-CNRS UMR 1572, Av. de la Terrasse, 91198 Gif sur Yvette, France
3 : UMR5805 EPOC – OASU, Université Bordeaux 1 – CNRS, Avenue des Facultés, 33405 Talence cedex, France
4 : NIOO-KNAW, Centre for Estuarine and Marine Ecology, Korringaweg 7, 4401 NT Yerseke, The Netherlands
5 : Laboratoire d'Aérologie, CNRS et Université de Toulouse, 14 avenue Edouard Belin, 31400 Toulouse, France
6 : Laboratoire des Bio-Indicateurs Actuels et Fossiles, UPRES EA 2644, UFR Sciences 2 bd Lavoisier, 49045 Angers Cedex 01, France
Source Biogeosciences (1726-4170) (Copernicus GmbH), 2011-05-27 , Vol. 8 , N. 5 , P. 1351-1366
DOI 10.5194/bg-8-1351-2011
WOS© Times Cited 29
Note Special issue Biogeochemical fluxes in River-dominated Ocean Margins (RiOMars): the Rhone delta (NW Mediterranean Sea) – river inputs, plume processes, benthic recycling, budgets and models
Abstract In situ oxygen microprofiles, sediment organic carbon content, and pore-water concentrations of nitrate, ammonium, iron, manganese, and sulfides obtained in sediments from the Rhone River prodelta and its adjacent continental shelf were used to constrain a numerical diagenetic model. Results showed that (1) the organic matter from the Rhone River is composed of a fraction of fresh material associated to high first-order degradation rate constants (11-33 yr(-1)); (2) the burial efficiency (burial/input ratio) in the Rh boolean AND one prodelta (within 3 km of the river outlet) can be up to 80 %, and decreases to similar to 20% on the adjacent continental shelf 10-15 km further offshore; (3) there is a large contribution of anoxic processes to total mineralization in sediments near the river mouth, certainly due to large inputs of fresh organic material combined with high sedimentation rates; (4) diagenetic by-products originally produced during anoxic organic matter mineralization are almost entirely precipitated (> 97 %) and buried in the sediment, which leads to (5) a low contribution of the re-oxidation of reduced products to total oxygen consumption. Consequently, total carbon mineralization rates as based on oxygen consumption rates and using Redfield stoichiometry can be largely underestimated in such River-dominated Ocean Margins (RiOMar) environments.
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Pastor L., Cathalot C., Deflandre B., Viollier E., Soetaert K., Meysman F. J. R., Ulses C., Metzger E., Rabouille C. (2011). Modeling biogeochemical processes in sediments from the Rhone River prodelta area (NW Mediterranean Sea). Biogeosciences, 8(5), 1351-1366. Publisher's official version : https://doi.org/10.5194/bg-8-1351-2011 , Open Access version : https://archimer.ifremer.fr/doc/00303/41423/