Future nutrient limitations across ecosystems - a dual look at nitrogen and phosphorus
We develop a fast protocol with isotope techniques to determine if nitrogen (N) or phosphorus (P) limitation is present and possibly shifting in a natural terrestrial ecosystem. This is carried out across sites with widely different geological parent material and long-term weathering history (Sweden, Germany, Rwanda and Australia), e.g. different N or P limitation. Treatment with elevated atmospheric CO2 (EucFACE and GiFACE) will elucidate the response in nutrient limitations to climate change. The experimental work with soils consists of combined laboratory assays for determining gross N and P mineralization rates and N depolymerization rate. At ecosystem level, our method presents an instant assessment of the soil nutrient dynamics and availability.