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| 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: https://archimer.ifremer.fr/doc/00431/54217/55547.pdf |
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| Taillefert, Martial; Beckler, Jordon S.; Cathalot, Cecile; Michalopoulos, Panagiotis; Corvaisier, Rudolph; Kiriazis, Nicole; Caprais, Jean-claude; Pastor, Lucie; Rabouille, Christophe. |
| Deep-sea fans are well known depot centers for organic carbon that should promote sulfate reduction. At the same time, the high rates of deposition of unconsolidated metal oxides from terrigenous origin may also promote metal-reducing microbial activity. To investigate the eventual coupling between the iron and sulfur cycles in these environments, shallow sediment cores (< 50 cm) across various channels and levees in the Congo River deep-sea fan (~5000 m) were profiled using a combination of geochemical methods. Interestingly, metal reduction dominated suboxic carbon remineralization processes in most of these sediments, while dissolved sulfide was absent. In some ‘hotspot’ patches, however, sulfate reduction produced large sulfide concentrations which... |
| Tipo: Text |
Palavras-chave: Sediment diagenesis; Iron reduction; Sulfate reduction; Deep-sea fans. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00389/50068/52254.pdf |
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