AUTHOR=Smith Geoffrey Battle , Tabocchini Maria Antonella , Garay Carlos Peña TITLE=Editorial: The Biogeochemistry, Biophysics, Radiobiology, and Technical Challenges of Deep Subsurface Research JOURNAL=Frontiers in Earth Science VOLUME=9 YEAR=2021 URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.678034 DOI=10.3389/feart.2021.678034 ISSN=2296-6463