The researchers have conducted a meta-analysis on gross N transformations in free air CO2 enrichment (FACE) experiments. Emerging from ecosystem specific analysis, a new conceptual model is proposed: Gross N mineralization is only stimulated in N-limited ecosystems, but unaffected in phosphorus (P) limited ecosystems. The implication of this is that N-limited ecosystems will be less prone to a progressive N limitation (PNL) at future elevated CO2 than earlier suggested, as increased gross N mineralization acts to sustain N availability for plants.
On a global scale if fewer ecosystems develop a PNL, sustained enhanced ecosystem productivity is possible at elevated CO2, as has been found in several long-term FACE studies. Global climate models recently incorporated the biogeochemical N cycle and ecosystem N limitation. However, if fewer N-limited ecosystems are prone to PNL these models potentially underestimate ecosystem carbon sequestration and overestimate the magnitude of climate warming.
You can find the article here: Rütting T & Andresen LC (2015) Nitrogen cycle responses to elevated CO2 depend on ecosystem nutrient status.
Contact
Tobias Rütting, University of Gothenburg