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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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| Sarazin, Gérard; Jezequel, Didier; Leboulanger, Christophe; Fouilland, Eric; Le Floc'H, Emilie; Bouvy, Marc; Gerard, Emmanuelle; Agogué, Hélène; Bernard, Cédric; Hugoni, Mylène; Grossi, Vincent; Trousselier, Marc; Ader, Magali. |
| Dziani Dzaha is a maar the age of which is close to 4000 years. While its water is thought to have originated from seawater it is now considered as an extreme environment due to its hypersaline and alkaline characteristics. Those extreme features have led to the simplification of the trophic network. Cyanobacteria account for up to 95% of the photosynthetic biomass. The main biogeochemical processes, i.e. photosynthesis, bacterial sulfate reduction and methanogenesis could explain the current water composition. As far as we know, this ecosystem could be unique on Earth, extending the nature and chemical limits of aquatic inland ecosystems |
| Tipo: Text |
Palavras-chave: Thalassohaline lake; Endorheic ecosystem; Cyanobacteria; Methane emission; Biogeochemistry; Mayotte. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00667/77948/80128.pdf |
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