Journal Article

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

Rollion-Bard, Claire, Laforest, Claude, Bankole, Olabode, Trentesaux, Alain, Aubineau, Jeremie, Reynaud, Jean Yves, Bengtson, Stefan, Fru, Ernest Chi, Mazurier, Arnaud, Baghekema, Stellina Gwenaelle Lekele, Fontaine, Claude, Macchiarelli, Roberto, Mangano, M. Gabriela, Buatois, Luis A., Canfield, Donald E., El Albani, Abderrazak, Riboulleau, Armelle, Konhauser, Kurt, Lyons, Timothy, Meunier, Alain, Gauthier-Lafaye, François, Bekker, Andrey, Recourt, Philippe

2019

Overview

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).

• Publisher: National Academy of Sciences
• Subject: Atmosphere / Biological Evolution / Biosphere / Biota / Biota - physiology / Cell migration / Compression / Den föränderliga jorden / Diagenesis / Earth Sciences / Earth, Atmospheric, and Planetary Sciences / Food resources / Fossils / Francevillian / Gabon / Geologic Sediments - chemistry / Marine environment / motility / Mud-water interfaces / Offshore structures / Oxidation / Oxidation-Reduction / Oxygen - chemistry / Oxygenation / Paleobiology / Paleontology / Paleoproterozoic Era / Physical Sciences / Sciences of the Universe / Slime molds / Starvation / The changing Earth / trace fossil