Swansong biospheres II: The final signs of life on terrestrial planets near the end of their habitable lifetimes

TY - JOUR

T1 - Swansong biospheres II

T2 - The final signs of life on terrestrial planets near the end of their habitable lifetimes

AU - O'Malley-James, Jack T.

AU - Cockell, Charles S.

AU - Greaves, Jane S.

AU - Raven, John A.

PY - 2014/7

Y1 - 2014/7

N2 - The biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due to the increased hostility of environmental conditions caused by the Sun as it enters the late stage of its main sequence evolution. Building on previous work, the productivity of the biosphere is evaluated during different stages of biosphere decline between 1 and 2.8Gyr from present. A simple atmosphere-biosphere interaction model is used to estimate the atmospheric biomarker gas abundances at each stage and to assess the likelihood of remotely detecting the presence of life in low-productivity, microbial biospheres, putting an upper limit on the lifetime of Earth's remotely detectable biosignatures. Other potential biosignatures such as leaf reflectance and cloud cover are discussed.

AB - The biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due to the increased hostility of environmental conditions caused by the Sun as it enters the late stage of its main sequence evolution. Building on previous work, the productivity of the biosphere is evaluated during different stages of biosphere decline between 1 and 2.8Gyr from present. A simple atmosphere-biosphere interaction model is used to estimate the atmospheric biomarker gas abundances at each stage and to assess the likelihood of remotely detecting the presence of life in low-productivity, microbial biospheres, putting an upper limit on the lifetime of Earth's remotely detectable biosignatures. Other potential biosignatures such as leaf reflectance and cloud cover are discussed.

UR - https://www.scopus.com/pages/publications/84903137645

U2 - 10.1017/S1473550413000426

DO - 10.1017/S1473550413000426

M3 - Article

AN - SCOPUS:84903137645

SN - 1473-5504

VL - 13

SP - 229

EP - 243

JO - International Journal of Astrobiology

JF - International Journal of Astrobiology

IS - 3

ER -