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Registros recuperados: 7
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A benthic Si mass balance on the Congo margin: Origin of the 4000 m DSi anomaly and implications for the transfer of Si from land to ocean ArchiMer
Ragueneau, O.; Regaudie-de-gioux, A.; Moriceau, B.; Gallinari, M.; Vangriesheim, Annick; Baurand, F.; Khripounoff, Alexis.
To elucidate the origin of the silicic acid (DSi) anomaly observed along the 4000 isobath on the Congo margin, we have established a benthic Si mass balance and performed direct measurements of biogenic silica (bSiO(2)) dissolution in the deep waters and in the sediments. Results strongly suggest that the anomaly originates from the sediments; the intensity of DSi recycling is consistent with the degradation of organic matter, as observed from Si:O-2 ratios in the benthic fluxes compared to that ratio observed in the anomalies. Strong imbalances, observed in both the Si and C mass balances, suggest that the biogenic matter that degrades and dissolves in these sediments near 4000 m does not come from pelagic sedimentation. It is probably not coming also...
Tipo: Text Palavras-chave: Congo; Continental margin; Preservation; Dissolution; Biogenic silica.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-7410.pdf
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A First Look at Dissolved Ge Isotopes in Marine Sediments ArchiMer
Baronas, J. Jotautas; Hammond, Douglas E.; Rouxel, Olivier; Monteverde, Danielle R..
The removal of chemical species from seawater during the precipitation of authigenic minerals is difficult to constrain but may play a major role in the global biogeochemical cycles of some elements, including silicon (Si) and germanium (Ge). Here, we present Ge/Si, δ74Ge, and supporting chemical data of pore waters and core incubations at three continental margin sites in California and the Gulf of Mexico. We used these data to partition Ge release and uptake by the various allogenic (delivered via sedimentation) and authigenic (formed in situ) phases in these sediments. About half of the pore water Ge (δ74Gepw = 1.3–2.4‰) is supplied by biogenic silica dissolution (δ74Ge ~ 3‰), with the other half contributed by lithogenic particulates (δ74Ge ~ 0.6‰)....
Tipo: Text Palavras-chave: Germanium; Biogenic silica; Authigenesis; Fe oxides; Isotope fractionation; Continental margin.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00504/61556/65466.pdf
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A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements ArchiMer
Sutton, Jill N.; Andre, Luc; Cardinal, Damien; Conley, Daniel J.; De Souza, Gregory F.; Dean, Jonathan; Dodd, Justin; Ehlert, Claudia; Ellwood, Michael J.; Frings, Patrick J.; Grasse, Patricia; Hendry, Katharine; Leng, Melanie J.; Michalopoulos, Panagiotis; Panizzo, Virginia N.; Swann, George E. A..
Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial...
Tipo: Text Palavras-chave: C - N - O - Si isotopes; Biogenic silica; Element/Si ratios; Biogeochemical cycles; Silicon.
Ano: 2018 URL: http://archimer.ifremer.fr/doc/00431/54217/55547.pdf
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Contribution of resuspended sedimentary particles to dissolved iron and manganese in the ocean: An experimental study ArchiMer
Cheize, Marie; Planquette, H.f.; Fitzsimmons, J.n.; Pelleter, Ewan; Sherrell, R.m.; Lambert, Christophe; Bucciarelli, E.; Sarthou, G.; Le Goff, Marion; Liorzou, Celine; Chéron, Sandrine; Viollier, E.; Gayet, Nicolas.
A number of trace metals play essential roles in marine ecosystem structure and biological productivity. Until recently, it has been argued that phytoplankton access primarily dissolved iron, while particulate iron was considered a refractory material with little use biologically and limited interaction with the dissolved pool. In order to assess the transfer mechanisms between sediment-sourced particulate trace metals and the dissolved pool, we conducted a 14-month incubation that reacted resuspended sediments with natural seawater, both originating from the Kerguelen area (KEOPS cruises; Southern Ocean), in the dark, and at concentrations replicating natural conditions. Three types of sediments were investigated (named BioSi, BioSi + Ca, and Basalt),...
Tipo: Text Palavras-chave: Suspended particle dissolution; Sediment; Iron; Manganese; Biogenic silica; Southern Ocean; Kerguelen.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00460/57197/59166.pdf
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Copepods Boost the Production but Reduce the Carbon Export Efficiency by Diatoms ArchiMer
Moriceau, Brivaela; Iversen, Morten H.; Gallinar, Morgane; Evertsen, Antti-jussi O.; Le Goff, Manon; Beker, Beatriz; Boutorh, Julia; Corvaisier, Rudolph; Coffineau, Nathalie; Donval, Anne; Giering, Sarah L. C.; Koski, Marja; Lambert, Christophe; Lampit, Richard S.; Le Mercier, Alain; Masson, Annick; Stibor, Herwig; Stockenreiter, Maria; De La Rocha, Christina L..
The fraction of net primary production that is exported from the euphotic zone as sinking particulate organic carbon (POC) varies notably through time and from region to region. Phytoplankton containing biominerals, such as silicified diatoms have long been associated with high export fluxes. However, recent reviews point out that the magnitude of export is not controlled by diatoms alone, but determined by the whole plankton community structure. The combined effect of phytoplankton community composition and zooplankton abundance on export flux dynamics, were explored using a set of 12 large outdoor mesocosms. All mesocosms received a daily addition of minor amounts of nitrate and phosphate, while only 6 mesocosms received silicic acid (dSi). This resulted...
Tipo: Text Palavras-chave: Biogenic silica; POC; Marine snow; Zooplankton; Mesocosm; Bay of Hopavagen; Plankton community; Biological pump.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00469/58029/60433.pdf
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Editorial: Biogeochemistry and Genomics of Silicification and Silicifiers ArchiMer
Moriceau, Brivaela; Gehlen, Marion; Treguer, Paul; Baines, Stephen; Livage, Jacques; Andre, Luc.
Tipo: Text Palavras-chave: Silicon cycle; Biogenic silica; Diatom; Isotope; Bolidophycae; Sponge (Porifera); Nanostructured silica; Anthropogenic pressure.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00488/59978/63223.pdf
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Silicon cycle in the NW Mediterranean Sea: seasonal study of a coastal oligotrophic site ArchiMer
Leblanc, K; Queguiner, B; Garcia, N; Rimmelin, P; Raimbault, P.
A study of the biogeochemical cycle of silicon has been conducted in the Gulf of Lion (NW Mediterranean) from September 1999 to September 2000. Most of the year the study site was under the influence of the NW Mediterranean Current, characterized by oligotrophic conditions. A seasonal pattern of silicon stocks was found, showing an inverse annual distribution of biogenic silica and lithogenic silica. Biogenic silica integrated stocks were higher during spring and summer (21.5 and 19.3 mmol m(-2)) due to siliceous phytoplankton Si uptake and build-up of biomass. By contrast lithogenic silica integrated stocks were highest during the fall and winter (61.8 and 45.0 mmol m(-2)), which may be explained by a higher degree of turbulence of the water column,...
Tipo: Text Palavras-chave: NW Mediterranean; Biogenic silica; Phytoplanktonic community; Limiting nutrient; Seasonal cycle.
Ano: 2003 URL: http://archimer.ifremer.fr/doc/00320/43092/42629.pdf
Registros recuperados: 7
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