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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... |
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Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71163/69492.pdf |
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Fossile, Eleonore; Nardelli, Maria Pia; Jouini, Arbia; Lansard, Bruno; Pusceddu, Antonio; Moccia, Davide; Michel, Elisabeth; Péron, Olivier; Howa, Hélène; Mojtahid, Meryem. |
The rapid response of benthic foraminifera to environmental factors (e.g., organic matter quality and quantity, salinity, pH) and their high fossilisation potential make them promising bio-indicators for the intensity and recurrence of brine formation in Arctic seas. Such approach, however, requires a thorough knowledge of their modern ecology in such extreme settings. To this aim, seven stations along a N–S transect across the Storfjorden (Svalbard archipelago) have been sampled using an interface multicorer. This fjord is an area of intense sea ice formation characterised by the production of Brine-enriched Shelf Waters (BSW) as a result of a recurrent latent-heat polynya. Living (Rose Bengal stained) foraminiferal assemblages were analysed together with... |
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Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00599/71122/69424.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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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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Cathalot, Cecile; Rabouille, Christophe; Tisnerat-laborde, N.; Toussaint, Flora; Kerherve, P.; Buscail, R.; Loftis, K.; Sun, M. -y.; Tronczynski, Jacek; Azoury, S.; Lansard, Bruno; Treignier, Claire; Pastor, L.; Tesi, T.. |
A significant fraction of the global carbon flux to the ocean occurs in River-dominated Ocean Margins (RiOMar) although large uncertainties remain in the cycle of organic matter (OM) in these systems. In particular, the OM sources and residence time have not been well clarified. Surface (0-1 cm) and sub-surface (3-4 cm) sediments and water column particles (bottom and intermediate depth) from the Rhone River delta system were collected in June 2005 and in April 2007 for a multi-proxy study. Lignin phenols, black carbon (BC), proto-kerogen/BC mixture, polycyclic aromatic hydrocarbons (PAHs), carbon stable isotope (delta C-13(OC)), and radiocarbon measurements (delta C-14(OC)) were carried out to characterize the source of sedimentary organic material and to... |
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Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00157/26784/25673.pdf |
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