A new study from southwest China reveals that earthquakes create two separate carbon cycles in mountain rivers. Landslides triggered by a quake send plant and soil carbon downstream quickly, but that biological pulse fades within a decade. Meanwhile, rock-derived carbon from broken bedrock continues washing into rivers for years, releasing ancient carbon that can affect climate models. Researchers used a heating method to distinguish between young organic carbon and old petrogenic carbon in river sediment. The technique is faster and cheaper than radiocarbon dating. The findings matter for carbon accounting in tectonically active regions, where post-earthquake sediment can skew estimates of carbon burial versus release.
