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| Hoshino, Yosuke; Poshibaeva, Aleksandra; Meredith, William; Snape, Colin; Poshibaev, Vladimir; Versteegh, Gerard J. M.; Kuznetsov, Nikolay; Leider, Arne; Van Maldegem, Lennart; Neumann, Mareike; Naeher, Sebastian; Moczydlowska, Malgorzata; Brocks, Jochen J.; Jarrett, Amber J. M.; Tang, Qing; Xiao, Shuhai; Mckirdy, David; Das, Supriyo Kumar; Alvaro, Jose Javier; Sansjofre, Pierre; Hallmann, Christian. |
| Sedimentary hydrocarbon remnants of eukaryotic C-26-C-30 sterols can be used to reconstruct early algal evolution. Enhanced C-29 sterol abundances provide algal cellmembranes a density advantage in large temperature fluctuations. Here, we combined a literature review with new analyses to generate a comprehensive inventory of unambiguously syngenetic steranes in Neoproterozoic rocks. Our results show that the capacity for C-29 24ethyl- sterol biosynthesis emerged in the Cryogenian, that is, between 720 and 635 million years ago during the Neoproterozoic Snowball Earth glaciations, which were an evolutionary stimulant, not a bottleneck. This biochemical innovation heralded the rise of green algae to global dominance of marine ecosystems and highlights the... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75021/75667.pdf |
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| Mertens, Kenneth; Gu, Haifeng; Takano, Yoshihito; Price, Andrea M.; Pospelova, Vera; Bogus, Kara; Versteegh, Gerard J. M.; Marret, Fabienne; Turner, R. Eugene; Rabalais, Nancy N.; Matsuoka, Kazumi. |
| We establish the cyst-theca relationship of the dinoflagellate cyst species Trinovantedinium pallidifulvum Matsuoka 1987 based on germination experiments of specimens isolated from the Gulf of Mexico. We show that the motile stage is a new species, designated as Protoperidinium louisianensis. We also determine its phylogenetic position based on single-cell polymerase chain reaction (PCR) of a single cell germinated from the Gulf of Mexico cysts. To further refine the phylogeny, we determined the large subunit (LSU) sequence through single-cell PCR of the cyst Selenopemphix undulata isolated from Brentwood Bay (Saanich Inlet, BC, Canada). The phylogeny shows that P. louisianensis is closest to P. shanghaiense, the motile stage of T. applanatum, and is... |
| Tipo: Text |
Palavras-chave: Micro-FTIR; Selenopemphix undulata; Wadden Sea; Lake Saroma; Saanich Inlet; Gulf of Mexico. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00385/49609/50120.pdf |
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| El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Bard, Claire Rollion; Macchiarelli, Roberto; Pemba, Lauriss Ngombi; Hammarlund, Emma; Meunier, Alain; Mouele, Idalina Moubiya; Benzerara, Karim; Bernard, Sylvain; Boulvais, Philippe; Chaussidon, Marc; Cesari, Christian; Fontaine, Claude; Chi-fru, Ernest; Garcia Ruiz, Juan Manuel; Gauthier-lafaye, Francois; Mazurier, Arnaud; Pierson-wickmann, Anne Catherine; Rouxel, Olivier; Trentesaux, Alain; Vecoli, Marco; Versteegh, Gerard J. M.; White, Lee; Whitehouse, Martin; Bekker, Andrey. |
| The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations similar to 2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation. While most sedimentary successions deposited during this time interval have experienced thermal overprinting from burial diagenesis and metamorphism, the ca. 2.1 Ga black shales of the Francevillian B Formation (FB2) cropping out in southeastern Gabon have not. The Francevillian Formation contains centimeter-sized structures interpreted as organized and spatially discrete populations of colonial organisms living in an oxygenated marine ecosystem. Here, new material from the FB2 black shales is presented and... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00202/31356/29754.pdf |
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| Mertens, Kenneth; Van Nieuwenhove, Nicolas; Gurdebeke, Pieter R.; Aydin, Hilal; Bogus, Kara; Bringue, Manuel; Dale, Barrie; De Schepper, Stijn; De Vernal, Anne; Ellegaard, Marianne; Grothe, Arjen; Gu, Haifeng; Head, Martin J.; Heikkila, Maija; Limoges, Audrey; Londeix, Laurent; Louwye, Stephen; Marret, Fabienne; Masure, Edwige; Matsuoka, Kazumi; Mudie, Peta J.; Penaud, Aurelie; Pospelova, Vera; Price, Andrea Michelle; Ribeiro, Sofia; Rochon, Andre; Sangiorgi, Francesca; Schreck, Michael; Torres, Vladimir; Uzar, Serdar; Versteegh, Gerard J. M.; Warny, Sophie; Zonneveld, Karin. |
| We present a summary of two round-table discussions held during two subsequent workshops in Montreal (Canada) on 16 April 2014 and Ostend (Belgium) on 8 July 2015. Five species of the genus Achomosphaera Evitt 1963 and 33 of the genus Spiniferites Mantell 1850 emend. Sarjeant 1970 occuring in Pliocene to modern sediments are listed and briefly described along with remarks made by workshop participants. In addition, several holotypes and topotypes are reillustrated. Three species previously assigned to Spiniferites are here considered/accepted as belonging to other genera: Impagidinium inaequalis (Wall and Dale in Wall et al. 1973) Londeix et al. 2009, Spiniferites? rubinus (Rossignol 1962 ex Rossignol 1964) Sarjeant 1970, and Thalassiphora balcanica... |
| Tipo: Text |
Palavras-chave: Spiniferites; Achomosphaera; Hafniasphaera; Rottnestia; Pterocysta. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58304/60844.pdf |
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