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| Donnadieu, Y; Lecroart, P; Anschutz, P; Bertrand, P. |
| We have constructed a nonsteady state numerical model of organic carbon, aluminum, and uranium burial to examine the dynamic response of sediments to variations on thousand years scale. The three components are defined by distinct behaviors in the sedimentary system. The aluminum is a conservative component, the organic carbon is a nonconservative component degraded in superficial sediment, and the uranium is a component affected by redox conditions. By introducing a simultaneous variation of incoming fluxes of C-org and Al, geochemical profiles of Al, Corg, and U clearly show separate distributions after burial. Each component record the synchronous variation of the incoming fluxes, but the position in the sedimentary pile of the recording differs from a... |
| Tipo: Text |
Palavras-chave: Time lag; Sedimentary system; High-resolution record; Modeling; Bioturbation. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33390/31872.pdf |
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| Rabouille, Christophe; Amouroux, D; Anschutz, P; Jouanneau, J.-m.; Gilbert, F; Cossa, Daniel; Prevot, F. |
| A general decrease in the anthropogenic pressure on coastal ecosystems has been observed recently in developed countries. But coastal lagoon ecosystems are still undergoing major human impact (Lotze et al., 2006). A major environmental concern is the enhancement of contaminant dispersion and algal production due to eutrophication, associated with an increase in the duration of intermittent seasonal periods of anoxia. Due to past industrial activity, large concentrations of contaminants have been accumulated in sediments of natural water bodies. One of the issues raised by environmentalists is the fate of these contaminants with changing environmental conditions, such as restoration of water bodies to their "pristine" state (water framework directives), or... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3037.pdf |
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| Anschutz, P; Blanc, G. |
| The 23,000 year old sediments of the Atlantis II Deep rest on a basaltic substratum and are overlaid by a dense and hot brine pool. The facies of the lower sequence of the West basin consists essentially of bioclastic and detrital particles (DOP facies). The primary calcite and aragonite of planktonic tests of the DOP facies have been transformed into Ca-, Mg-, Mn-, and Fe-carbonate solid solutions. Pyrite amounts to about 1-2% (wt) at the bottom of the sedimentary series, and as much as 20% (wt) in the upper part of the sequence. These high iron - and manganese - earing minerals are the product of early diagenetic processes in an environment favourable to bacterial activity, to which biogenic and detrital particles, organic matter, and iron and manganese... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00097/20863/18481.pdf |
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| Deborde, J; Anschutz, P; Auby, Isabelle; Gle, C; Commarieu, M; Maurer, Daniele; Lecroart, P; Abril, G. |
| The hypothesis of nutrient-rich pore-waters seeping at low tide through sediments to channel waters, which drain tidal flats during ebb, was evaluated in the Arcachon lagoon. The back of the bay is affected by freshwater inputs and underground freshwater discharges. The upper part of tidal flat consists of permeable sandy sediments, which are covered by a muddy sediment layer on the lower part. Permeable sediments outcrop in the bed of channel web. Surface water chemistry and early diagenesis processes in sediment were estimated by collecting channel web waters and cores on a tidal flat and in channels at different seasons and time scales. Waters from tidal creeks are under-oxygenated, and enriched in reduced solutes. Muddy sediments showed evidences of... |
| Tipo: Text |
Palavras-chave: Arcachon Bay; Pore waters seeping; Nitrogen; Phosphorus; Organic matter mineralization; Tidal creek water; Tidal pump. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/2008/publication-3927.pdf |
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