biosphere Archives

Geographic location and origin of samples. Maps of samples used for metabarcoding of 16S rRNA gene amplicon taxonomic marker genes (A) and shotgun metagenomic analyses of unassembled and de novo assembled taxonomic marker genes (B). Each symbol represents one project, which comprises multiple individual samples. Both terrestrial as well as marine samples may contain rock, sediment, or water samples. Further maps showing sample material, pH and temperature are included in the Supplementary Material (Fig. S1). (C) Overview of sample origins derived from marine and terrestrial biomes, depth realms, and environments. -- biorxiv.org

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Gaia - Planetary Perspectives, Genomics, Proteomics, Bioinformatics, Habitable Zones, Microbiology & Virology, ROVs/Submersibles/Diving, Sample Return, Status Report, Water/Hycean Worlds & Oceanography

A Global Atlas Of Subsurface Microbiomes Reveals Phylogenetic Novelty, Large Scale Biodiversity Gradients, And A Marine-terrestrial Divide

by Keith CowingMay 3, 2024May 3, 2024

Subsurface environments constitute one of Earth’s largest habitats for microbial life, yet differences between surface and subsurface microbiomes and between marine and terrestrial microbiomes remain unclear.

Simulated oxygen (left; a,d,g), sulfate (middle; b,e,h), and methane (right; c,f,i) concentrations in a Proterozoic-like ocean with 10-3 PAL O2. Maps show each species in surface seawater (top; a-c) and benthic seawater (middle; d-f). Also shown are zonal average vertical profiles (bottom; g-i). Oxygen is limited to oxygen oases in surface seawater, leading to extensive SO4 2- reduction and local SO4 2- scarcity at depth, especially underlying productive regions of the surface ocean and in the oldest bottom waters. Where SO4 2- concentrations are low, methanogenesis leads to CH4 accumulation, but CH4 must evade oxidation by both SO4 2- in the ocean interior and O2 in surface waters before it may enter the atmosphere. This figure is reproduced from Reinhard et al. (2020) under Creative Commons Attribution License CCBY. Nitrous oxide (N2O -- astro-ph.EP

Analog Studies, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Fossils & Paleontology, Gaia - Planetary Perspectives, Habitable Zones, Origin & Evolution of Life, Status Report, Terraforming & Geoengineering

The Early Earth As An Analogue For Exoplanetary Biogeochemistry

by Keith CowingApril 25, 2024April 25, 2024

Planet Earth has evolved from an entirely anoxic planet with possibly a different tectonic regime to the oxygenated world with horizontal plate tectonics that we know today.

Reflectance spectra of purple and blue-green cyanobacteria (top), PNSB (N = 10) (middle), and, PSB (N = 12) (bottom) where N denotes the number of samples. Labels of main pigments identified: (a) Chl-a Soret band, (b) Carotenoids, (c) Chl-a Qx band, (d) Phycobilins, (e) Chl-a Qy band, (f) BChl-a Soret band, (g) BChl-a, b Qx band, (h) BChl-a Qy band, and (i) BChl-b Qy band. Dry samples (right) show a stronger reflectance than fresh samples (left), water absorption features at 1490 and 1900 nm are stronger in the fresh samples. The reflectance of the culture medium alone is shown as a dotted line for control.

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Microbiology & Virology, Status Report, Water/Hycean Worlds & Oceanography

Purple Is The New Green: Biopigments And Spectra Of Earth-like Purple Worlds

by Keith CowingApril 18, 2024April 18, 2024

With more than 5,500 detected exoplanets, the search for life is entering a new era. Using life on Earth as our guide, we look beyond green landscapes to expand our […]

Shows the CH4 production rate from ecosystem 1 for the 3.8 Ga Earth (dashed) and TRAPPIST-1e (solid) case. The CH4 production rate is split between anoxic H2 (purple) and CO (grey) consumers. the total of these is also shown (green) This plot used simulations with the reduced network. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

Biosignatures From Pre-oxygen Photosynthesising Life On TRAPPIST-1e

by Keith CowingApril 18, 2024April 18, 2024

In order to assess observational evidence for potential atmospheric biosignatures on exoplanets, it will be essential to test whether spectral fingerprints from multiple gases can be explained by abiotic or […]

Atmospheres, Climate, Weather, Gaia - Planetary Perspectives, Habitable Zones, Microbiology & Virology, Status Report

Detecting Microbiology In The Upper Atmosphere: Relative-velocity Filtered Sampling

by Keith CowingOctober 15, 2023October 15, 2023

The purpose of this paper is to re-open from a practical perspective the question of the extent in altitude of the Earth’s biosphere.

Information transmission rate associated with communication (in bits/s) as a function of the calendar year. The dashed line is the rate estimated for the biosphere (assuming it is roughly constant on short timescales) and the solid line signifies the rate for the technosphere given by (3).

Gaia - Planetary Perspectives, Societal Issues, Status Report

Opinion: Planetary Scale Information Transmission in the Biosphere and Technosphere: Limits and Evolution

by Keith CowingSeptember 30, 2023September 30, 2023

Information transmission via communication between agents is ubiquitous on Earth, and is a vital facet of living systems.

Phanerozoic biodiversity curves. (a) Total Phanerozoic diversity based on raw data82 divided into its three main Evolutionary Faunas (EF), i.e. the Cambrian trilobites, the Paleozoic brachiopods, and the modern gastropods. Tese are three distinct types of fauna whose diversity pattern expanded and contracted in a similar fashion throughout the diferent phases of the Phanerozoic. Each EF includes specifc taxonomic classes that were most abundant during (but not limited to) a certain period in Earth’s history. Furthermore, the EFs successively replaced one another as the principal group throughout the Phanerozoic. Te red arrows represent the Big Five mass extinction events, including the Ordovician–Silurian extinction (~445 Ma ago), Devonian extinction (~375 Ma ago), Permian–Triassic extinction (~250 Ma ago), Triassic-Jurassic extinction (~200 Ma ago) and the Cretaceous-tertiary extinction (~66 Ma ago)81. (b) Corrected biodiversity curve using the shareholder quorum subsampling (SQS) sample standardization method34. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Status Report

Variations In Climate Habitability Parameters And Their Effect On Earth’s Biosphere During The Phanerozoic Eon

by Keith CowingAugust 16, 2023August 16, 2023

Essential insights on the characterization and quality of a detectable biosphere are gained by analyzing the effects of its environmental parameters. We compiled environmental and biological properties of the Phanerozoic […]

Chemical pathways during spark discharge in N2−O2 (left) and N2−CO2 (right) gas mixtures. Once NO is produced, further oxidation follows the same reactions in both cases: NO is oxidised to NO2 , some being converted to N2O3 and N2O4 . In N2−CO2 experiments, O2 is produced by the recombination of atomic oxygen. All gaseous nitrogen oxides equilibrate with water and convert to HNO2 and HNO3 . HNO2 is thermodynamically unstable and will oxidise to HNO3 . Both acids may dissociate to nitrite (NO – 2 ) and nitrate (NO – 3 ), respectively, depending on solution pH. In a low-pH environment, HNO2 is more abundant than NO – 2 , allowing further oxidation to HNO3 and nitrate. The dominant pathways are indicated with bold arrows and coloured molecule labels. -- physics.geo-ph

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Habitable Zones, Origin & Evolution of Life, Status Report

Isotopic Constraints On Lightning As A Source Of Fixed Nitrogen In Earth’s Early Biosphere

by Keith CowingMay 24, 2023May 24, 2023

Bioavailable nitrogen is thought to be a requirement for the origin and sustenance of life. Before the onset of biological nitrogen fixation, abiotic pathways to fix atmospheric N2 must have […]

An exploded star can pose more risks to nearby planets

Astronomy & Telescopes, Exoplanets, -moons, -comets, Extinction events, Habitable Zones, Space Weather & Heliophysics

New Stellar Danger to Exoplanets Identified by Chandra X-ray Observatory

by Keith CowingApril 21, 2023April 27, 2023

An exploded star can pose more risks to nearby planets than previously thought, according to a new study from NASA’s Chandra X-ray Observatory and other X-ray telescopes. This newly identified […]

Structure and genetics of the nitrogenase G-subunit. A) Left, crystallographic structure of the extant A. vinelandii Vnf nitrogenase complex (VnfH, PDB 6Q9336; VnfDGK, PDB 5N6Y22 ) containing the G-subunit (dark blue). The Anf nitrogenase is inferred to be comparable in its multimeric structure, binding FeFe-co instead of FeV-co. Right, crystallographic structure of the extant Nif nitrogenase complex (NifH, PDB 1M3437; NifDK, PDB 3U7Q38) lacking the G subunit. B) Secondary structure of the Vnf G-subunit. C) Arrangement of the Nif, Vnf, and Anf structural genes in A. vinelandii. Vnf/AnfG (dark blue) is located between Vnf/AnfD and Vnf/AnfK genes. -- biorxiv.org

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Microbiology & Virology, Plant Biology, Status Report

An Orphan Protein Drove The Ecological Expansion Of Nitrogen Fixation

by Keith CowingApril 10, 2023April 10, 2023

Nitrogenases have catalyzed biological nitrogen fixation for billions of years and revolutionized planet Earth by supplying essential nitrogen to the biosphere.

biosphere

A Global Atlas Of Subsurface Microbiomes Reveals Phylogenetic Novelty, Large Scale Biodiversity Gradients, And A Marine-terrestrial Divide

The Early Earth As An Analogue For Exoplanetary Biogeochemistry

Purple Is The New Green: Biopigments And Spectra Of Earth-like Purple Worlds

Biosignatures From Pre-oxygen Photosynthesising Life On TRAPPIST-1e

Detecting Microbiology In The Upper Atmosphere: Relative-velocity Filtered Sampling

Opinion: Planetary Scale Information Transmission in the Biosphere and Technosphere: Limits and Evolution

Variations In Climate Habitability Parameters And Their Effect On Earth’s Biosphere During The Phanerozoic Eon

Isotopic Constraints On Lightning As A Source Of Fixed Nitrogen In Earth’s Early Biosphere

New Stellar Danger to Exoplanets Identified by Chandra X-ray Observatory

An Orphan Protein Drove The Ecological Expansion Of Nitrogen Fixation

Early-career Graduate Students Host An Exclusive, NASA-funded Astrobiology Conference

Intimate Link Between Prebiotic Chemistry And Meteorites: Mechanisms Of Organic Molecule Formation

Microbial Mats Influence The Isotopic Composition And Provenance of Soil Organic Matter In The McMurdo Dry Valleys, Antarctica

Beyond The Prebiotic Soup: Solid Organic Films And Protocell-Like Formation in Prebiotic Discharge Experiments

From Searching For Extraterrestrial Biosignatures To Exploring The Origins Of Life: A Prebiotic Chemistry Perspective