Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago

Abderrazak El Albani (1) , M. Gabriela Gabriela Mangano (2) , Luis Buatois (2) , Stefan Bengtson (3) , Armelle Riboulleau (4) , Andrey Bekker (5) , Kurt O. Konhauser (6) , Timothy Lyons (5) , Claire Rollion-Bard (7) , Olabode Bankole (1) , Alain Meunier (1) , Alain Trentesaux (4) , Arnaud Mazurier (1) , Jérémie Aubineau (1) , Claude Laforest (1) , Claude Fontaine (1) , Philippe Recourt (4) , Ernest Chi Fru (8) , Roberto Macchiarelli (9, 10) , Stellina Gwenaëlle Lekele Baghekema (1) , Jean-Yves Reynaud (11, 4) , François Gauthier-Lafaye (12) , Donald E Canfield

1 IC2MP [Poitiers] - Institut de chimie des milieux et matériaux de Poitiers [UMR 7285]
2 U of S - University of Saskatchewan [Saskatoon, Canada]
3 NRM - Swedish Museum of Natural History
4 LOG - Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187
5 UC Riverside - University of California [Riverside]
6 Department of Earth and Atmospheric Sciences [Edmonton]
7 IPGP - Institut de Physique du Globe de Paris
8 Cardiff University
9 HNHP - Histoire naturelle de l'Homme préhistorique
10 Palevoprim [Poitiers] - Laboratoire de paléontologie, évolution, paléoécosystèmes, paléoprimatologie [UMR 7262]
11 Université de Lille
12 LHyGeS - Laboratoire d'Hydrologie et de Géochimie de Strasbourg

Evidence for macroscopic life in the Paleoproterozoic Era comes from1.8 billion-year-old (Ga) compression fossils [Han TM, Runnegar B (1992) Science 257:232–235; Knoll et al. (2006) Philos Trans R Soc Lond B 361:1023–1038], Stirling biota [Bengtson S et al. (2007) Paleobiology 33:351–381], and large colonial organisms exhibiting signs of coordinated growth from the 2.1-Ga Francevillian series, Gabon. Here we report on pyritized string-shaped structures from the Francevillian Basin. Combined microscopic, microtomographic, geochemical, and sedimentologic analyses provide evidence for biogenicity, and syngenicity and suggest that the structures underwent fossilization during early diagenesis close to the sediment–water interface. The string-shaped structures are up to 6 mm across and extend up to 170 mm through the strata. Morphological and 3D tomographic reconstructions suggest that the producer may have been a multicellular or syncytial organism able to migrate laterally and vertically to reach food resources. A possible modern analog is the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds at times of starvation. This unique ecologic window established in an oxygenated, shallow-marine environment represents an exceptional record of the biosphere following the crucial changes that occurred in the atmosphere and ocean in the aftermath of the great oxidation event (GOE).

Domaines: Paléontologie; Sciences de la Terre

Abderrazak El Albani, M. Gabriela Gabriela Mangano, Luis Buatois, Stefan Bengtson, Armelle Riboulleau, et al.. Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago. Proceedings of the National Academy of Sciences of the United States of America, 2019, 116 (9), pp.3431-3436. ⟨10.1073/pnas.1815721116⟩. ⟨hal-02170144⟩