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| Titel |
Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea) |
| VerfasserIn |
L. Pastor, C. Cathalot, B. Deflandre, E. Viollier, K. Soetaert, F. J. R. Meysman, C. Ulses, E. Metzger, C. Rabouille |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 5 ; Nr. 8, no. 5 (2011-05-27), S.1351-1366 |
| Datensatznummer |
250005826
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| Publikation (Nr.) |
 copernicus.org/bg-8-1351-2011.pdf |
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| Zusammenfassung |
| In situ oxygen microprofiles, sediment organic carbon content, and pore-water
concentrations of nitrate, ammonium, iron, manganese, and sulfides obtained
in sediments from the Rhône River prodelta and its adjacent continental
shelf were used to constrain a numerical diagenetic model. Results showed
that (1) the organic matter from the Rhône 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 Rhône prodelta (within 3 km of the river outlet) can be up to
80 %, and decreases 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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