2017/07/03 by Daniel R. Colman, Saroj Poudel, Blake W. Stamps +2 · 1 citation
Environmental Science · Earth and Planetary Sciences · #Methane Hydrates and Related Phenomena #Microbial Community Ecology and Physiology #Geology and Paleoclimatology Research #Biosphere #Earth science #Earth (classical element) #Earth system science #Lead (geology) #Astrobiology #Environmental science #Ecology #Geology #Biology #Paleontology
paper · doi:10.1073/pnas.1701266114
openalex publication_date 2017/07/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/02
Twenty-five years ago this month, Thomas Gold published a seminal manuscript suggesting the presence of a “deep, hot biosphere” in the Earth’s crust. Since this publication, a considerable amount of attention has been given to the study of deep biospheres, their role in geochemical cycles, and their potential to inform on the origin of life and its potential outside of Earth. Overwhelming evidence now supports the presence of a deep biosphere ubiquitously distributed on Earth in both terrestrial and marine settings. Furthermore, it has become apparent that much of this life is dependent on lithogenically sourced high-energy compounds to sustain productivity. A vast diversity of uncultivated microorganisms has been detected in subsurface environments, and we show that H 2 , CH 4 , and CO feature prominently in many of their predicted metabolisms. Despite 25 years of intense study, key questions remain on life in the deep subsurface, including whether it is endemic and the extent of its involvement in the anaerobic formation and degradation of hydrocarbons. Emergent data from cultivation and next-generation sequencing approaches continue to provide promising new hints to answer these questions. As Gold suggested, and as has become increasingly evident, to better understand the subsurface is critical to further understanding the Earth, life, the evolution of life, and the potential for life elsewhere. To this end, we suggest the need to develop a robust network of interdisciplinary scientists and accessible field sites for long-term monitoring of the Earth’s subsurface in the form of a deep subsurface microbiome initiative.