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| Cadeau, Pierre; Jézéquel, Didier; Leboulanger, Christophe; Fouilland, Eric; Le Floc’h, Emilie; Chaduteau, Carine; Milesi, Vincent; Guélard, Julia; Sarazin, Gérard; Katz, Amandine; D’amore, Sophie; Bernard, Cecile; Ader, Magali. |
| The Proterozoic Era records two periods of abundant positive carbon isotope excursions (CIEs), conventionally interpreted as resulting from increased organic carbon burial and leading to Earth’s surface oxygenation. As strong spatial variations in the amplitude and duration of these excursions are uncovered, this interpretation is challenged. Here, by studying the carbon cycle in the Dziani Dzaha Lake, we propose that they could be due to regionally variable methane emissions to the atmosphere. This lake presents carbon isotope signatures deviated by ~ + 12‰ compared to the modern ocean and shares a unique combination of analogies with putative Proterozoic lakes, interior seas or restricted epireic seas. A simple box model of its Carbon cycle demonstrates... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00656/76784/77944.pdf |
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| Gerard, Emmanuelle; De Goeyse, Siham; Hugoni, Mylene; Agogue, Helene; Richard, Laurent; Milesi, Vincent; Guyot, Francois; Lecourt, Lena; Borensztajn, Stephan; Joseph, Marie-beatrice; Leclerc, Thomas; Sarazin, Gerard; Jezequel, Didier; Leboulanger, Christophe; Ader, Magali. |
| Lake Dziani Dzaha is a thalassohaline tropical crater lake located on the "Petite Terre" Island of Mayotte (Comoros archipelago, Western Indian Ocean). Stromatolites are actively growing in the shallow waters of the lake shores. These stromatolites are mainly composed of aragonite with lesser proportions of hydromagnesite, calcite, dolomite, and phyllosilicates. They are morphologically and texturally diverse ranging from tabular covered by a cauliflower-like crust to columnar ones with a smooth surface. High-throughput sequencing of bacterial and archaeal 16S rRNA genes combined with confocal laser scanning microscopy (CLSM) analysis revealed that the microbial composition of the mats associated with the stromatolites was clearly distinct from that of the... |
| Tipo: Text |
Palavras-chave: Stromatolites; Alkaline lake; Pleurocapsales; Mg-silicate; Alphaproteobacteria; Anoxygenic phototrophic bacteria; Aragonite; Hydromagnesite. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00443/55451/56970.pdf |
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