Rapid warming is currently accelerating Arctic carbon cycling. This includes increasing CO2 release by degradation of thawing soil organic matter and increasing CO2 uptake by better-growing plants. Projections of future Arctic greenhouse gas fluxes do not consider plant-soil interactions that can substantially affect CO2 release – the rhizosphere priming effect.
PRIMETIME aims to provide the first observation-based estimate of total plant effects on circum-Arctic soil and ecosystem carbon stocks in a changing climate. Central questions include:
(1) How do different vegetation types affect soil carbon dynamics and CO2 fluxes?
(2) How do changes in rooting depth interact with depth gradients of soil properties to affect carbon stocks and CO2 fluxes?
(3) What is the combined effect of expected changes in vegetation productivity, distribution and rooting on CO2 fluxes across the circum-Arctic?
These questions will be addressed by integrating field and laboratory experiments using a range of isotopic tools and large-scale modelling.