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| Rassmann, Jens; Lansard, Bruno; Pozzato, Lara; Rabouille, Christophe. |
| The Rhône River is the largest source of terrestrial organic and inorganic carbon for the Mediterranean Sea. A large fraction of this terrestrial carbon is either buried or mineralized in the sediments close to the river mouth. This mineralization follows aerobic and anaerobic pathways, with a range of impacts on calcium carbonate precipitation and dissolution in the sediment near the sediment–water interface. This study focuses on the production of dissolved inorganic carbon (DIC) and total alkalinity (TA) by early diagenesis, consequential pH variations and the effect on calcium carbonate precipitation or dissolution. The sediment porewater chemistry was investigated along a transect from the Rhône River outlet to the continental shelf. TA and... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00354/46505/46267.pdf |
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| Rassmann, Jens. |
| Continental shelves are key regions for the global carbon cycle and particularly exposed to ocean acidification. A large part of organic matter (OM) of continental and marine origin is mineralized in estuarine sediments following oxic and anoxic pathways. This mineralization produces dissolved inorganic carbon (DIC) leading to acidification of the bottom waters. Anoxic mineralization can produce total alkalinity (TA) that can contribute to buffer bottom water pH and increase the CO2 storage capacity of seawater. Measurements in the sediments of the Rhone River prodelta showed that anoxic mineralization, especially sulfate reduction, are the major pathways of OM mineralization and create high DIC and TA fluxes. Land derived OM is mineralized close to the... |
| Tipo: Text |
Palavras-chave: Carbonate system; Early diagenesis; Mineralization; Pelagic-bentic fluxes; Rhone prodelta; Ocean acidification. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00659/77076/78398.pdf |
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| Rassmann, Jens; Eitel, Eryn M.; Lansard, Bruno; Cathalot, Cecile; Brandily, Christophe; Taillefert, Martial; Rabouille, Christophe. |
| Estuarine regions are generally considered a major source of atmospheric CO2, as a result of the high organic carbon (OC) mineralization rates in their water column and sediments. Despite this, the intensity of anaerobic respiration processes in the sediments tempered by the reoxidation of reduced metabolites near the sediment–water interface controls the flux of benthic alkalinity. This alkalinity may partially buffer metabolic CO2 generated by benthic OC respiration in sediments. Thus, sediments with high anaerobic respiration rates could contribute less to local acidification than previously thought. In this study, a benthic chamber was deployed in the Rhône River prodelta and the adjacent continental shelf (Gulf of Lion, northwestern Mediterranean) in... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71163/69492.pdf |
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| Rassmann, Jens; Lansard, Bruno; Pozzato, Lara; Rabouille, Christophe. |
| The Rhône River is the largest source of terrestrial organic and inorganic carbon for the Mediterranean Sea, and a large fraction thereof is buried or mineralized in the sediments close to the river mouth. The mineralization follows aerobic and anaerobic pathways with varying impacts on the carbonate chemistry in the sediment pore waters. This study focused on the production of dissolved inorganic carbon (DIC) and total alkalinity (TA) by early diagenesis at the sediment water-interface, consequential pH variations and the effect on calcium carbonate precipitation or dissolution. The sediment pore water chemistry was investigated during the DICASE cruise along a transect from the Rhône River outlet to the continental shelf. The concentrations of DIC, TA,... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00337/44838/44422.pdf |
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