biosphere Archives

Global Carbon Fixation In Earth’s Subsurface Biosphere

by Keith CowingSeptember 2, 2026September 2, 2026

[biorxiv.org] The subsurface of our planet hosts 15% of Earth’s biomass and plays a key role in mediating the exchange of volatiles and elements between deep, long-residence-time geological reservoirs and […]

A NASA satellite monitors the edge of Earth to study how the planet’s atmosphere is changing. -- NASA larger image

Atmospheres, Climate, Weather

Atmospheres As Habitats

by Keith CowingAugust 10, 2026August 10, 2026

[Astrobiology (Journal)]. The potential of planetary atmospheres as habitats is understudied and likely underestimated. Although planetary atmospheres can provide the fundamental physical, chemical, and energetic requirements for life, they also […]

In a new study, researchers provide measures of elevation and climate around 47 sites in the U.S. National Ecological Observatory Network, from Florida’s Everglades to the Alaskan tundra hundreds of miles above the Arctic Circle. Credit Courtesy of Kelly Kapsar, Michigan State University

Biosignatures & Paleobiology

Orbital Biosphere Assays: Lowering Barriers To Big Data

by Keith CowingAugust 10, 2026August 10, 2026

Editor’s note: When we begin to conduct Away Team visits to other worlds that host life we will need to do an assay of how everything on these worlds works […]

Inhabited world with city lights - Grok via Astrobiology.com

Biosignatures & Paleobiology

Substrate-Agnostic 3x: Biosignatures, Technosignatures, Ecologies

by Keith CowingJuly 22, 2026July 22, 2026

[physics.gen-ph] Substrate-agnostic perspectives are currently attracting increased attention. For example, it has become customary to refer to agnostic biosignatures to reflect the range of alternative extraterrestrial biospheres and to account […]

Planetary Protection & Biosafety

NAS Committee On Planetary Protection Seeks Membership Suggestions

by Keith CowingJuly 15, 2026July 15, 2026

The National Academies are seeking suggestions for experts to be considered for membership or other engagement with the Committee on Planetary Protection (CoPP). Learn more and submit suggestions here by […]

A schematic showing the key abitoic (black dashed boxes) and biotic (white dashed box) processes occurring in the model (reproduced from Nicholson et al. 2022). -- [astro-ph.EP]

Biosignatures & Paleobiology

A Generalised Microbial Cell Model For Methane Biosignature Predictions

by Keith CowingJuly 13, 2026July 13, 2026

[astro-ph.EP] The majority of potentially habitable planets detected to date are likely quite different to Earth, for example, being larger in radius and mass, differing rotation rates and with host […]

Closed ecosystem. Two microbial populations are present: a resident community of natural organisms (N) and a mirror-life population (M). -- bioRxiv.org

Nanotechnology & SynBio

Ecological Constraints To Mirror Life

by Keith CowingJune 30, 2026June 30, 2026

[bioRxiv] Our biosphere exhibits remarkable diversity yet is constrained by universal organizational principles, including molecular homochirality.

Life emerges on a new world -- Grok via Astrobiology.com

Origin & Evolution of Life

The Biological Cosmological Constant ΛB: Exploratory Propensity, Dynamical Habitability And The Geometric Origin Of Life

by Keith CowingJune 29, 2026June 29, 2026

[BioSystems via PubMed] The emergence of life represents a fundamental geometric phase transition in the state space of complex systems, rather than a mere sequence of chemical syntheses. Building upon […]

ExoCAM simulations of Earth from the present up to 2.0 Gyr in the future, assuming CO2 remains fixed at 400 ppm. The top row shows surface temperature, the middle row shows precipitation minus evaporation, and the bottom row shows the habitability metric developed by Woodward et al. (2025) (Eqs. (D1) and (D2)). All quantities are 20-year averages after the model has reached a steady-state. Increases in temperature due to a brightening sun cause an increase in habitability up to 1.5 Gyr due to the greening of the poles, but habitability decreases significantly by 2.0 Gyr as Earth becomes too hot for complex vegetative life. This corresponds to a weak temperature dependence of weathering, in which Earth’s CO2 levels do not change even as the climate warms (c.f., Graham et al., 2024). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Desert Worlds, Gaia - Planetary Perspectives, Imaging & Spectroscopy, Space Agriculture, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Maximum Lifetime Of The Vegetative Biosphere

by Keith CowingMay 23, 2026May 23, 2026

We use a three-dimensional model to calculate steady-state climates at various intervals in Earth’s future, across a parameter space of increasing insolation and decreasing CO2 mixing ratio.

A schematic illustration of the geological and geochemical characteristics of the pre-biotic Earth. The important characteristics include: the nearly-completely ocean-covered Earth; the continental crust mostly submerged in the oceans; the degassing of gases/fluids to the oceans mostly by reducing submarine hydrothermal fluids; the H2–CH4–NH3-rich atmosphere; the Fe–S–H+-poor oceans; the origin and evolution of life on ocean islands; and an organic haze layer for the protection of life from UV radiation from the sun. -- Scientific Reports

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

The Hydrogen, Methane And Ammonia Biosphere On Early Earth

by Keith CowingMay 4, 2026May 4, 2026

Current paradigms for the origin and evolutions of life and the environment on early Earth have been based on the premises that carbon dioxide (CO2) and nitrogen gas (N2) were […]