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| Caley, Thibaut; Extier, Thomas; Collins, James A.; Schefuss, Enno; Dupont, Lydie; Malaize, Bruno; Rossignol, Linda; Souron, Antoine; Mcclymont, Erin L.; Jimenez-espejo, Francisco J.; Garcia-comas, Carmen; Eynaud, Frederique; Martinez, Philippe; Roche, Didier M.; Jorry, Stephan; Charlier, Karine; Wary, Melanie; Gourves, Pierre-yves; Billy, Isabelle; Giraudeau, Jacques. |
| The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution1,2,3,4. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions2,5 or a stable hydroclimate6. By contrast, records from Lake Malawi in tropical southeastern Africa reveal a trend of a progressively wetter climate over the past 1.3 million years7,8. The climatic forcings that controlled these past hydrological changes are also a matter of debate. Some studies suggest a dominant local insolation forcing on hydrological changes9,10,11, whereas others infer a potential influence of sea surface temperature changes in the Indian Ocean8,12,13. Here we show... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00449/56059/57581.pdf |
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| Penaud, Aurelie; Hardy, William; Lambert, Clement; Marret, Fabienne; Masure, Edwige; Seryais, Thomas; Siano, Raffaele; Wary, Melanie; Mertens, Kenneth. |
| Dinoflagellates are part of the marine plankton and about 200 species produce a cyst (dinocyst) during their life cycle, these organic-walled sexually-produced cysts being fossilizable in sediments for hundreds of millions of years. Over the past 40–50 years, dinocysts have led to major advances on Mesozoic-Cenozoic research, in terms of biostratigraphy and paleogeogeography. Dinocyst taxonomy has then been continuously revised, with the tabulation being the main morphological link between living dinoflagellates and fossilized cysts. Over the Quaternary, and based on the principle of uniformitarianism (i.e. species ecology did not change through time), relationships between modern assemblages and present-day environmental factors controlling their... |
| Tipo: Text |
Palavras-chave: Dinoflagellate; Cyst-motile stage relationship; Modern dinocyst distribution; Paleoecology; Biostratigraphy; Ancient DNA. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00463/57476/59749.pdf |
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| Wary, Melanie; Eynaud, Frederique; Swingedouw, Didier; Masson-delmotte, Valerie; Matthiessen, Jens; Kissel, Catherine; Zumaque, Jena; Rossignol, Linda; Jouzel, Jean. |
| Dansgaard-Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48-30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53149/55328.pdf |
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