Great Oxidation Event Archives

Oxygen produced by cyanobacteria may have created the conditions for green seas in the Archaean era (1.8 - 3 billion years ago) (Credit: Takashi Tsujino)

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Microbiology & Virology, Origin & Evolution of Life, Press Release, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Were Earth’s Blue Oceans Once Green?

by Keith CowingMarch 30, 2025March 30, 2025

Scientists find evidence that our oceans used to be green, suggesting that this may be a sign of primitive life, including that on alien worlds.

An example of stromatolites investigated in the study found in the Cheshire Formation of the Belingwe greenstone belt, Zimbabwe. Photo credit: Professor Axel Hofmann

Astrogeology, Away Teams & Field Reports, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Fossils & Paleontology, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Microbiology & Virology, Origin & Evolution of Life, Press Release, Water/Hycean Worlds & Oceanography

Impact Of Volcanic Activity On Early Marine Life

by Keith CowingMarch 3, 2025

Analysis of fossilised rocks known as stromatolites from more than two-and-a-half billion years ago has provided new insights into the conditions on Earth before the evolution of oxygen.

Distribution of Asgardarchaeota based on the recovery of MAGs from a wide variety of habitats. The ecological distribution of the Asgardarchaeota genomes across 12 environments, including genomes added by this study (purple star) and the total number of MAGs (yellow circle). The bar chart shows the number of MAGs from each lineage by environment, indicating lineages found only in a single environment (Atabeyarchaeia; teal triangle), circular complete genomes (black circle), and MAGs with known associated viruses or proviruses (blue phage). We note the novel class, Ranarchaeia, and recently described Asgardarchaeia in the legend with asterisks. Guaymas Basin is shown separately from the other bathypelagic-associated MAGs to showcase the increased genomic diversity from this site. -- biorxiv.org

Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Status Report

Oxygen Metabolism In Descendants Of The Archaeal-Eukaryotic Ancestor

by Keith CowingJuly 8, 2024July 7, 2024

Asgard archaea were pivotal in the origin of complex cellular life. Hodarchaeales (Asgardarchaeota class Heimdallarchaeia) were recently shown to be the closest relatives of eukaryotes. However, limited sampling of these […]

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Press Release, Water/Hycean Worlds & Oceanography

Geologic Record Demonstrates How Earth’s Oceans Were Oxygenated 2.3 billion Years Ago

by Keith CowingJune 13, 2024September 18, 2025

About 2.5 billion years ago, free oxygen, or O2, first started to accumulate to meaningful levels in Earth’s atmosphere, setting the stage for the rise of complex life on our […]

Images of microfossil specimens of Navifusa majensis. (Demoulin et al., Nature, 2024) [L] one of the microfossils with stacks of thylakoids highlighted using yellow bars [R] magnification of the end of the cell.

Biosignatures & Paleobiology, Fossils & Paleontology, Imaging & Spectroscopy, Microbiology & Virology, Origin & Evolution of Life, Plant Biology, Status Report

Fossil Cells Provide Evidence Of Early Oxygenic Photosynthesis On Earth

by Keith CowingJanuary 4, 2024January 4, 2024

Today oxygenic photosynthesis is unique to cyanobacteria and their plastid relatives within eukaryotes. Although its origin before the Great Oxidation Event is still debated 1,2,3,4, the accumulation of O2 profoundly […]

Microfossils are contained within black chert like the ones seen here. CREDIT Provided by Erica Barlow

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extinction events, Fossils & Paleontology, Microbiology & Virology, Origin & Evolution of Life, Press Release

New Microfossils Suggest An Earlier Rise In Complex Life On Earth

by Keith CowingNovember 7, 2023November 7, 2023

Microfossils from Western Australia may capture a jump in the complexity of life that coincided with the rise of oxygen in Earth’s atmosphere and oceans, according to an international team […]

Bacterial evolution through geological time. (a) The early evolution of bacterial genetic diversity in the Archaean (David and Alm 2010) is reflected by rapid increase in gene content disparity (see Supplementary Material). (b) A persistent higher diversification rate of aerobes since the GOE. The line charts the relative diversification rate (the ratio of the inverse of the waiting time to the next speciation event) for aerobic and anaerobic lineages, revealing a persistent higher diversification rate of aerobes for most of the Earth’s history since the GOE. Rates equilibrated prior to the NOE, before a return to higher diversification rates for aerobes since the GOE. The dotted line denotes a ratio of 1, where the diversification rate of aerobic and anaerobic lineages is equal. Terminal branches were omitted and ratios since 100 Mya were not calculated do to a low number of nodes. (c) Spread of aerobic metabolism by HGT. Transitions from anaerobic to aerobic lifestyles have outnumbered transitions in the reverse direction/back transitions/returns to anaerobicity for most of Earth history since the GOE. The plots show the ratio of aerobic to anaerobic transition rates on the dated species tree during each time period. The dotted line denotes a ratio of 1, where transitions occur in both directions at the same rate. The small number of nodes since ~200 Ma greatly increases uncertainty for both analyses, as reflected in the wide confidence intervals of posterior node age estimates. Ratios since 100 Mya were not calculated due to a low number of nodes. (d) shows the number of aerobic lineages according to Figure 2, e) qualitative sketch of atmospheric oxygen levels through time based on (Lyons, Reinhard, and Planavsky 2014; Poulton et al. 2021; Krause et al. 2022). The grey line shows the Moon-forming impact at ~4.52 Ga; the green line at ~3.23 Ga reflects the presence of fossil and isotopic evidence for oxygenic photosynthesis; the red line at ~2.33 Ga reflects the end of the GOE (see calibrations in Supplementary Material). --- biorxiv.org

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Microbiology & Virology, Origin & Evolution of Life, Status Report

An Evolutionary Timescale For Bacteria Calibrated Using The Great Oxidation Event

by Keith CowingAugust 16, 2023August 16, 2023

Most of life’s diversity and history is microbial but it has left a meagre fossil record, greatly hindering understanding of evolution in deep time.

Living stromatolites at Shark Bay, Western Australia. Oxygen produced by ancient stromatolites may have left its mark on Earth's environment as early as 2.5 billion years ago. Photo courtesy Ariel Anbar

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Origin & Evolution of Life, Press Release

ASU-led Team Defends Molecular Oxygen Findings

by Keith CowingApril 12, 2023April 12, 2023

When did molecular oxygen, the gas that all large and complex forms of life on Earth today require to function, first appear on Earth?

Two proposed mechanisms for H2O2 generation at quartz–water interfaces. (A) Stress-induced cleavage of Si–O bonds. Applied force is represented by a linear falling potential (dashed line), which is added to the Morse potential of the unstretched Si–O bond (dotted line), thus resulting in a force-deformed Morse potential (solid line). The new dissociation energy D′ is smaller than D in the case of a stretching force. Modified after Kauzmann et al. (42). The probability of generation of surface-bound radicals in quartz therefore increases during mechanical processes. (B) Contact of water on freshly fractured surface of abraded quartz. Modified after Schoonen et al. (32). (C) Generation of H2O2 and O2 in the reaction between H2O and oxygen radical (≡SiO•). (D) Generation of rocky H2O2 and O2 in the reaction between H2O and peroxy radical (≡SiOO•). Surface-bound radicals are formed through homolysis of Si–O bonds, including ≡SiO•, ≡SiOO•, and E′ center (≡Si•), while surface charges (≡Si+ and ≡SiO–) for heterolysis. Silanol groups (≡SiOH) are end products on quartz surface after hydroxylation. -- Guangzhou Institute

Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Origin & Evolution of Life, Press Release

A Novel Origin Of Abiotic Oxidants On Early Earth: Minerals

by Keith CowingMarch 23, 2023March 23, 2023

Molecular oxygen (O2) is essential for respiration on today’s Earth, but the early atmosphere was almost devoid of oxygen until the Great Oxidation Event. How then did Earth’s atmosphere become […]

Biogeochemical Cycles & Geobiology, Habitable Zones, Origin & Evolution of Life, Press Release

How Fluctuating Oxygen Levels May Have Accelerated Animal Evolution On Earth

by Keith CowingOctober 17, 2022October 17, 2022

Oxygen levels in the Earth’s atmosphere are likely to have “fluctuated wildly” one billion years ago, creating conditions that could have accelerated the development of early animal life, according to new […]