Funds from this grant provide two years of operational and research support to the Extreme Physics and Chemistry Community of the Deep Carbon Observatory (DCO). The Extreme Physics and Chemistry community is a global network of researchers working together to better our understanding of the physical and chemical properties of carbon in the high temperature, high pressure environments characteristic of the deep Earth. Led by geophysicist Wendy Mao of Stanford and geologist Craig Manning of UCLA, the community is concerned with the 90% of Earth’s carbon that resides in the interior as solids, magmas and melts, and low density fluids. It addresses the transformations that occur both as carbon rises from the core to the mantle to the crust and also as surface carbon is subducted beneath the crust and subjected to extraordinary temperatures and pressures. Grant funds will support research and administrative costs of the Extreme Chemistry community as it moves towards the planned conclusion of the DCO in 2019, with the majority of funds supporting a network of postdoctoral research associates at 20 participating institutions. Other funds support workshops, “hackathons,” and computational simulation and modeling work associated with integrating insights from the community with discoveries by the larger DCO community.