Forms and fluxes of carbon: Surface to deep

Carbon is an essential element for the coevolution of Earth and life, and its largest fraction is stored in the deep Earth. The availability of carbon at the Earth's surface or shallow subsurface over the past 3.8 billion years has been modulated by this reservoir of deep carbon, which has played a fundamental role in the emergence and diversification of life. In turn, major geobiological changes at the Earth's surface have profoundly affected the chemical fingerprints and morphological forms of carbon entering the deep Earth through subduction. This chapter presents an overview of the geology of deep carbon, from its origins and forms throughout the Earth's history, to its movements and fluxes between shallow and deep reservoirs.