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Archean molecular fossils and the early rise of eukaryotes.
The presence of steranes, particularly cholestane and its 28- to 30-carbon analogs, provides persuasive evidence for the existence of eukaryotes 500 million to 1 billion years before the extant fossil record indicates that the lineage arose.
Reassessing the first appearance of eukaryotes and cyanobacteria
The results eliminate the evidence for oxygenic photosynthesis ∼2.7 Gyr ago and exclude previous biomarker evidence for a long delay between the appearance of oxygen-producing cyanobacteria and the rise in atmospheric oxygen 2.45–2.32 billion years ago.
Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea
Hydrocarbon biomarkers from a 1.64-Gyr-old basin in northern Australia reveal a marine basin with anoxic, sulphidic, sulphate-poor and permanently stratified deep waters, hostile to eukaryotic algae, and support mounting evidence for a long-lasting Proterozoic world in which oxygen levels remained well below modern levels.
A reconstruction of Archean biological diversity based on molecular fossils from the 2.78 to 2.45 billion-year-old Mount Bruce Supergroup, Hamersley Basin, Western Australia
Abstract Bitumens extracted from 2.7 to 2.5 billion-year-old (Ga) shales of the Fortescue and Hamersley Groups in the Pilbara Craton, Western Australia, contain traces of molecular fossils. Based on
Composition and syngeneity of molecular fossils from the 2.78 to 2.45 billion-year-old Mount Bruce Supergroup, Pilbara Craton, Western Australia
Shales of very low metamorphic grade from the 2.78 to 2.45 billion-year-old (Ga) Mount Bruce Supergroup, Pilbara Craton, Western Australia, were analyzed for solvent extractable hydrocarbons. Samples
De novo metagenomic assembly reveals abundant novel major lineage of Archaea in hypersaline microbial communities
Reconstruction of two highly unusual archaeal genomes by de novo metagenomic assembly of multiple, deeply sequenced libraries from surface waters of Lake Tyrrell, Australia demonstrates that even historically well-characterized environments can reveal unexpected diversity when analyzed by metagenomics, and advances the understanding of the ecology of hypersaline environments and the evolutionary history of the archaea.
The rise of algae in Cryogenian oceans and the emergence of animals
A molecular fossil record of eukaryotic steroids is presented demonstrating that bacteria were the only notable primary producers in the oceans before the Cryogenian period, and it is proposed that the incumbency of cyanobacteria was broken by a surge of nutrients supplied by the Sturtian deglaciation.
Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation
Abstract Carbonates of the 1640 million years (Ma) old Barney Creek Formation (BCF), McArthur Basin, Australia, contain more than 22 different C40 carotenoid derivatives including lycopane,
Phylogenetic and biochemical evidence for sterol synthesis in the bacterium Gemmata obscuriglobus
The primitive sterols produced by Gemmata suggest that this genus could retain the most ancient remnants of the sterol biosynthetic pathway, which was exchanged between bacteria and early eukaryotes via lateral gene transfer or endosymbiotic events.
Sedimentary Hydrocarbons, Biomarkers for Early Life
Molecular biological markers, or biomarkers, are natural products that can be assigned to a particular biosynthetic origin. For environmental and geological studies, the most useful molecular