oxygen Archives - Astrobiology

South Africa’s exceptionally preserved ancient rocks hold key evidence for the rise ofatmospheric oxygen. Within them, researchers see the disappearance of sulfur mass-independent fractionation, evidence for a GOE. Credit Photo by Daniel Hentz, ©Woods Hole Oceanographic Institution

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Habitable Zones, Press Release

A New Study Reveals How Oxygen First Reached Earth’s Oceans

by Keith CowingDecember 10, 2025December 10, 2025

For roughly two billion years of Earth’s early history, the atmosphere contained no oxygen, the essential ingredient required for complex life. Oxygen began building up during the period known as […]

Conceptual model for the evolution of exoenzymes and the recycling of organic matter across the Great Oxidation Event (GOE). (A) In the Archean Ocean, prior to the GOE, the recycling of organic matter depended entirely on the activity of fermenters. This resulted in low recycling efficiency, elevated carbon burial, and limited regeneration of essential nutrients back into seawater. This scarcity of particulate organic matter (POM) also reduced the availability of niches for microbial colonization, thus limiting the selective pressure for the evolution of exoenzyme systems. (b) Following the GOE, rising oxygen levels increased the availability of high-energy electron acceptors (e.g. O2, nitrate and ferric iron), supporting the expansion of metabolic groups with high exoenzyme capacity, such as aerobic heterotrophs, dissimilatory nitrate reducers and dissimilatory ferric iron reducers. Concurrently, increases in POM abundance and microbial cell densities would have amplified the selective pressure to produce exoenzymes. Collectively, these changes in the Paleoproterozoic promoted more efficient recycling of organic matter and regeneration of nutrients back into the water column, ultimately fueling greater primary productivity and oxygen release. This feedback between exoenzyme evolution, nutrient cycling, and oxygen production would have amplified Earth’s progressive oxygenation. -- biorxiv.org

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

Microbial Exoenzymes Catalyzed The Transition To An Oxygenated Earth

by Keith CowingOctober 11, 2025October 11, 2025

Microbial exoenzymes—extracellular enzymes secreted to degrade complex organic polymers— are essential for recycling carbon and nutrients, thus sustaining primary productivity in today’s oceans.

The solid curve represents the average dissolved oceanic Ni concentration (nmol L−1). Light blue indicates pO2 (Present Atmospheric Level, PAL). Changes in urea concentration are indicated by a red gradient (darker red represents higher concentrations). The average dissolved oceanic Ni concentration is plotted on data from ref. 26, and the Oxygen evolution curve is from ref. 1. Solar Lyman α flux is from ref. 83. -- Nature

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Habitable Zones, Origin & Evolution of Life, Press Release, Water/Hycean Worlds & Oceanography

Earth’s Oxygen Boom: A Fresh Perspective For A Billion-year-old Problem

by Keith CowingOctober 10, 2025October 10, 2025

The appearance of oxygen in Earth’s atmosphere was a turning point in the history of our planet, forever transforming the environment and setting the stage for complex life. This event, […]

Efficiency factors of crystalline ice grains with carbon inclusions for grain radii of 1 (red), 2 (blue), 5 (green), and 10 µm (brown). The inclusion fraction is set as 0.1. (a) The solid lines indicate the extinction efficiency factors in the 3 µm region. The scattering and absorption efficiency factors for a 2 µm grain are also shown with the dotted and dashed lines. (b) Absorption efficiency factors in the FIR. The colors are the same as in (a). -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

Searching For Missing Interstellar Oxygen In The Far-infrared

by Keith CowingSeptember 3, 2025

Study of interstellar elemental depletion poses an important problem in the interstellar matter that at least a quarter of the total oxygen (∼160 ppm relative to hydrogen) is not accounted […]

a, NIRCam false-colour image, where each colour channel was constructed by stacking NIRCam filters as annotated. The placement of the NIRSpec micro-shutters is shown in white (nearly identical across the all visits). Dashed coloured circles indicate the 0.3 "-diameter apertures used to extract the CIRC2 photometry. The [O iii] 88 µm emission and the MIRI/F560W image are overlaid with red and green contours respectively, both drawn at 3σ-4σ-5σ. A red (green) hatched ellipse shows the ALMA restoring beam (F560W point spread function). A horizontal bar indicates a physical scale of 1 kpc at z = 11.122. b, SEDs of the main component (A) of JADES-GS-z11- 0, as observed by NIRCam, MIRI, and NIRSpec/PRISM (Section 2.1), as well as the faint neighbouring source (B) whose photometry (filter curves drawn at the bottom) is consistent with having the same redshift. The best-fit bagpipes models are shown as solid (component A) and dashed (B) coloured lines, with squares indicating the model photometry. c, Best-fit model SFHs of the two components, with shading representing 1σ uncertainty. The dotted black line and grey shading illustrates the rising SFH prior based on dark matter halo accretion (see text for details), scaled to the stellar mass of component A. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

On The Origins Of Oxygen: ALMA And JWST Characterise The Multi-phase, Metal-enriched, Star-bursting Medium Within A ‘Normal’ z>11 Galaxy

by Keith CowingAugust 2, 2025August 2, 2025

The unexpectedly high abundance of galaxies at z>11 revealed by JWST has sparked a debate on the nature of early galaxies and the physical mechanisms regulating their formation.

The solar wind flows around Earth's magnetic field. A new NASA study suggests that the amount of oxygen in the atmosphere and strength of the magnetic field have been correlated for more than half a billion years. NASA's Goddard Space Flight Center/Conceptual Image Laboratory

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Imaging & Spectroscopy, Magnetic Fields, Electromagnetism, bioelectricity,, Space Weather & Heliophysics, Status Report

Connections Have Been Discovered Between Earth’s Oxygen And Its Magnetic Field

by Keith CowingJune 20, 2025June 20, 2025

For 540 million years, the ebb and flow in the strength of Earth’s magnetic field has correlated with fluctuations in atmospheric oxygen, according to a newly released analysis by NASA […]

Earth as seen by the Apollo 11 crew -- NASA

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Gaia - Planetary Perspectives, Mars, Moon, Status Report

Earth’s Composition: Origin, Evolution and Energy Budget

by Keith CowingMay 7, 2025May 7, 2025

One in every two atoms in the Earth, Mars, and the Moon is oxygen; it is the third most abundant element in the solar system.

This image shows the precise location in the night sky of the galaxy JADES-GS-z14-0, an extremely tiny dot in the Fornax constellation. As of today, this is the most distant confirmed galaxy we know of. Its light took 13.4 billion years to reach us and shows the conditions of the Universe when it was only 300 million years old. The inset of the image shows a close-up of this primordial galaxy as seen with the Atacama Large Millimeter/submillimeter Array (ALMA). The inset is overlaid on an image taken with the NASA/ESA/CSA James Webb Space Telescope. Credit: ALMA (ESO/NAOJ/NRAO)/S. Carniani et al./S. Schouws et al/JWST: NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA) Larger image

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Press Release

Oxygen Has Been Discovered In The Most Distant Known Galaxy JADES-GS-z14-0

by Keith CowingMarch 20, 2025March 20, 2025

Two different teams of astronomers have detected oxygen in the most distant known galaxy, JADES-GS-z14-0. The discovery, reported in two separate studies, was made possible thanks to the Atacama Large […]

A complex web of interactions between geological features including volcanoes, subsurface mantle, oceans and the atmosphere created the chemical mixture necessary for early life to oxygenate our atmosphere. -- Credit ©2025 Watanabe et al. CC-BY-ND

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Gaia - Planetary Perspectives, Habitable Zones, Lava / magma ocean / Volcanic Worlds, Microbiology & Virology, Press Release, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Are Volcanoes Behind The Oxygen We Breathe?

by Keith CowingMarch 12, 2025March 12, 2025

It is widely believed that Earth’s atmosphere has been rich in oxygen for about 2.5 billion years due to a relatively rapid increase in microorganisms capable of performing photosynthesis. Researchers, […]

Statistical power of the habitable zone oxygen hypothesis test on the ELT for different values of η⊕ and different fractions of exo-Earth candidates (EECs, left) and fractions of exo-super Earth candidates (ESECs, right) with Earth-like levels of O2. Statistical power contours for 50% and 95% are shown in black. More planets with oxygen and/or higher values for η⊕ result in a greater ability to test this hypothesis, however, the inclusion of all super-Earths does not necessarily improve this ability. We note that these figures are super-sampled to highlight differences. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Proxima Centauri, Status Report

Bioverse: GMT and ELT Direct Imaging and High-Resolution Spectroscopy Assessment – Surveying Exo-Earth O2 and Testing the Habitable Zone Oxygen Hypothesis

by Keith CowingFebruary 1, 2025February 1, 2025

Biosignature detection in the atmospheres of Earth-like exoplanets is one of the most significant and ambitious goals for astronomy, astrobiology, and humanity. Molecular oxygen is among the strongest indicators of […]