This grant to the Deep Carbon Observatory (DCO) supports seven field studies, including the extraction and analysis of deep Earth drilling cores, at seven sites around the globe. Sample types and locations include: Hydrocarbons and microbes from fluids, Canadian Shield (Ontario, Canada); Surface-collected, carbon-bearing sediments and carbonate reefs, North Pole Dome (Western Australia); Hydrocarbons and deep microbes recovered from drilling, Songliao Basin (Northeastern China); High-pressure metamorphic rocks, graphite, and carbonates, Alpine Corsica (France); Possibly abiotic hydrocarbons recovered from drilling, Romashkino oil field (Tatarstan, Russia); (Sub)seafloor methane hydrates (clathrates), water-column methane, Eastern Siberian Arctic Ocean Seafloor; Altered ocean crust and mantle, Samail ophiolite (Oman). Sites were selected through a year-long collaborative process involving the entire DCO community.  Together with cores already in repositories, new samples from these sites will complement the two dozen other locations where researchers are already working (such as volcanoes) in a way that DCO leaders believe will allow the program to achieve its decadal goals.