Attending the Goldschmidt 2018 meeting in Boston, August 12-17? Please consider submitting your abstracts, due March 30, 2018, to Session 10a: Geomicrobiology and Microbial Persistence in the Deep Biosphere (conveners Jiasong Fang, Lars Wörmer, Kasper Kjeldsen, Beth Orcutt, Yohey Suzuki): The continental and marine subsurface hosts microbial life that is involved in globally-significant geochemical transformations while existing under energy limitation and other extreme conditions. Recent advances in developing new and improved detection techniques, lowering detection limits, and increasing single cell and molecular-level resolution have uncovered new information about the size and forms of microbial life in this biosphere, physiologies of microbial groups, and possible evolutionary and adaptation mechanisms at play. However, much is still to be learned about the limits, diversity, extent and function of deep biosphere life. This session invites multidisciplinary contributions that present new findings from continental and/or marine subsurface environments, including “windows” into these systems such as deep-sea hydrothermal vents and cold seeps as well as hot springs and mud volcanoes on land and in the ocean. In particular, we welcome contributions that highlight strategies of microbial persistence in the deep biosphere, such as the formation and dispersal of endospores and other persistence forms. See more deep biosphere-related sessions under Theme 10: Geobiology, Organic Tracers, and Biogeochemistry.