NITROPRIME: Quantifying the impact of plant-soil interactions on plant nutrition and carbon sequestration in a warming Arctic

The Arctic is warming at rates twice the global average, increasing CO2 production by degradation of thawed soil organic matter, but also plant CO2 uptake. The balance between these processes is a key control of the future Arctic and global greenhouse gas balance. Plants additionally stimulate degradation near roots – the rhizosphere priming effect.

Priming can induce globally-relevant CO2 production from Arctic soils, but might also stimulate plant CO2 uptake by accelerating recycling of plant-available N from soil organic matter.

The importance of this effect is unknown and “a large source of uncertainty in projecting land-climate interactions” (IPCC).

NITROPRIME aims to quantify the effect of accelerated degradation near roots on plant N supply and CO2 uptake in a changing Arctic.WP-STABILIZATION will test to what extent, and by what mechanisms, different Arctic plants alter N availability near their roots, using a root exclusion field experiment.WP-TRADE will test to what extent plant C investment in roots and associated fungi accelerates soil N recycling and improves plant N nutrition, using a dual isotope labeling field experiment.

These data will be combined with an ecosystem C and N flux model to quantify the effect of projected vegetation shifts on N availability and plant C uptake.Combining field experiments and modeling, NITROPRIME will break new ground and allow to quantify the impact of priming on N cycling and plant CO2 uptake in a changing Arctic.