Contrasted detection of lipid biomarkers in Ediacaran stromatolites from Amane-n’Tourhart in the Moroccan Anti-Atlas

Abstract

During the Ediacaran Period (635 - 538.8 Ma), the photosynthetic activity due to cyanobacterial communities and early photosynthetic eukaryotes prompted the wide oxygenation of the terrestrial atmosphere. Biogeochemical evidence of this type of communities and activity in different terrestrial environments is very scarce. In this work, we search for lipid biomarkers and their carbon specific isotopic composition in stromatolites from an Ediacaran volcanic alkaline lake in the Anti-Atlas Mountains, in Morocco. Molecular analysis reveals the presence of n-alkanes, isoprenoids, hopanes and steranes in the Amane-n’Tourhart stromatolites, with compound-specific d13C values for n-alkanes and isoprenoids within the range of autotrophic organisms using the Calvin-Benson-Bassham cycle. Results from contamination controls and laboratory tests attest for the indigeneity and syngenicity of the detected biomarkers. In addition, molecular and isotopic analysis of hydrocarbons allows for the recognition of phototrophic activity from the prokaryotic and eukaryotic communities developed in this extreme alkaline lake in anoxic conditions. These unique results shed light on a key Period in the evolution of life on Earth in the particular region of Amane-n’Tourhart. The set of molecular and isotopic biomarkers detected in the Amane-n’Tourhart stromatolites supports the presence of some of the first complex organisms (i.e. fungi and early animals) and the relevance of the most prominent metabolism in present day biology (i.e. Calvin cycle), and expands the catalog of biomarkers preserved from that geological Period to reconstruct its paleobiology.

Keywords

Lipid biomarkers / Stable-carbon isotopes / Stromatolites / Ediacaran / Alkaline environments / Photosynthetic organisms

CRediT authorship contribution statement

Daniel Carrizo: Writing - original draft, Methodology, Investigation, Data curation, Conceptualization. Mohamed Beraaouz: Writing - review & editing, Methodology, Investigation. Mohammed Hssaisoune: Validation, Resources, Methodology. Laura Sánchez-García: Writing - review & editing, Writing - original draft, Investigation, Conceptualization. Olga Prieto-Ballesteros: Writing - review & editing, Methodology, Formal analysis, Data curation. Víctor Parro: Writing - review & editing, Supervision.

Data availability

The data and materials that support the findings of this study are available from the first and corresponding author, Daniel Carrizo, uponreasonablerequest.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This research has been funded by the Spanish Ministry of Science and Innovation/State Agency of Research MCIN/AEI/10.13039/501100011033 and ‘‘ERDF A way of making Europe” through the grants PID2022-140180OB-C21 (D.C.), RYC2018-023943-I (L. S.-G.), PID2022-142490OB-C31 (O.P.-B), and PCI2023-145992 (O. P.-B.), and PID2021-126746NB-I00 (V.P. and L.S.-G.).

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.gsf.2026.102251.

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