Department Seminar: Sue Trumbore

Title: Radiocarbon constraints for the terrestrial carbon cycle

Abstract: Radiocarbon (14C) is our major tool for understanding the dynamics of C exchanged between terrestrial ecosystems and the atmosphere on timescales of years to millennia.  For the last 6 decades, excess or ‘bomb’ 14C, the global isotopic label made available by atmospheric nuclear weapons testing, can be tracked through ecosystem compartments to determine how long  the C fixed each year by photosynthesis persists in plants, litter and soil organic matter and how fast it is returned to the atmosphere by respiration.  This talk will summarize major lessons learned in the ERC-funded 14Constraint project that focussed on using  radiocarbon to improve observational constraints on the dynamics of C cycling in ecosystem.   The talk will focus on the need to get away from comparing measures of mean values and suggest ways to characterize the distributions of ages and transit times in ecosystems.