Paper No. 11
Presentation Time: 11:30 AM


SCHIFFRIES, Craig M., HAZEN, Robert M., HEMLEY, Russell J. and MANGUM, Andrea J., Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015,

Carbon forms the chemical backbone for all essential biomolecules and is the element of life. Carbon-based fuels supply most of society’s energy. Carbon-bearing molecules in the atmosphere play a vital role in climate change. Despite carbon’s importance, remarkably little is known about the physical, chemical, and biological behavior of carbon-bearing systems in the vast majority of Earth’s interior. A transformational understanding of Earth’s deep carbon cycle will greatly advance our understanding of the planet

Past consideration of the global carbon cycle has focused primarily on the oceans, atmosphere, and shallow crust, with the implicit understanding that these reservoirs exchange carbon relatively rapidly as an essentially closed system. Our knowledge of carbon in Earth’s deep interior, which may contain more than 90% of planet’s carbon, is highly limited. Little is known about deep carbon reservoirs and fluxes, including exchanges between deep and near-surface reservoirs. We are largely ignorant of the nature and extent of deep microbial ecosystems, which by some estimates rival the total surface biomass. It is unclear if deep-Earth processes generate significant quantities of hydrocarbons or other organic species.

The Deep Carbon Observatory is an international, interdisciplinary, decade-long initiative dedicated to improving our knowledge of the deep carbon cycle and achieving a fundamental understanding of Earth through carbon. It was launched in 2009 with major support from the A.P. Sloan Foundation following an exploratory study involving 300 researchers. The Deep Carbon Observatory’s Decadal Goals are: (1) To improve our understanding of the physical and chemical behavior of carbon at extreme conditions found in the deep interiors of Earth and other planets; (2) To identify the principal deep carbon reservoirs and fluxes and to asses the total carbon budget of Earth; (3) To document the nature, sources, and evolution of subsurface organic molecules, including hydrocarbons and biomolecules; and (4) To assess the nature and extent of the deep microbial biosphere.