Department Logo for Earth, Planetary, and Space Sciences

Perturbations on the organic carbon cycle from human activities and earthquakes


March 9, 2018, noon - 1 p.m.
Slichter 3853

Presented By:
Gen Li
UCLA

See Event on Google. Subscribe to Calendar

Over geological timescales, continental erosional processes exert a primary control on the global carbon cycle. Specifically, river systems transport particulate organic carbon (POC) from continental carbon reservoirs to oceans. The burial of this riverine-exported POC in marine sediments represents a major geological sink of atmospheric CO2, whose magnitude is comparable to silicate weathering. Previous studies gauged short-term (annual to decadal) riverine POC fluxes, but lacked constraints on the fluctuations caused by abrupt, catastrophic events. In this presentation, I will first show how human activities,specifically dam building and the combustion of coals, affect the cycling of organic carbon in the Yangtze river basin, China. Taking the 2008 great Sichuan earthquake as another case study, I will then discuss how a high-magnitude seismic event enhances mountain denudation and promotes erosion of organic carbon from biomass, soils, and bedrocks in the Yangtze headwater regions. Overall, these projects provide key insights into carbon dynamics in areas undergoing significant changes driven by human activities and natural catastrophic events.