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, but a large source of uncertainty to model projections. NITROPRIME aims to quantify the effect of accelerated degradation near roots on plant N supply and CO2 uptake in a changing Arctic.
Central research questions:
- To what extent, and by what mechanisms, do different Arctic plants alter nitrogen availability near their roots?
- To what extent does carbon investment in roots and associated fungi by different plants accelerate nitrogen recycling from soil organic matter and improve plant nitrogen nutrition?
- To what extent will projected vegetation shifts change nitrogen availability and plant carbon uptake?
NITROPRIME addresses these questions by combining experimental and modeling tools.