Matthieu Galvez shows how the OC cycle connects Earth’s biosphere and geosphere

Branco Weiss Fellow Matthieu Galvez is the lead author of a new paper published recently in Nature Geoscience discussing how the organic carbon (OC) cycle – the long-term coevolution between biosphere and geosphere – on Earth has changed over Millions of years. The paper focusses on the diversity of the materials and processes that form the architecture of the OC cycle, and their evolution through time. It discusses the mechanisms of OC accumulation in both surface and deep Earth reservoirs over long timescales, and the atmospheric consequences of this accumulation.

The photosynthesis, transport, decay and accumulation of organic matter in the lithosphere distinguishes Earth from other planets in our Solar System. Over geological time, chemical exchanges between surface and deep Earth reservoirs have produced a diversity of reduced carbon materials that differ in their molecular structures and reactivity.

Among the by-products of the OC cycle are the accumulation of a massive lithospheric reservoir of organic carbon, the accumulation of dioxygen in the atmosphere and the rise of a terrestrial biosphere. Besides driving surface weathering reactions, free dioxygen has allowed the evolution of new metabolic pathways to produce and respire organic carbon. From the evolution of photosynthesis until the expansion of biomineralization in the Phanerozoic, inorganic controls on the organic carbon cycle have diversified, tightening the connection between the biosphere and geosphere.

Read the paper on Nature Geoscience