N2O Budgets in Peatlands - from Process to Ecosystem

ongoing

Nitrous oxide (N2O) is a powerful greenhouse gas and dangerous stratospheric O3 depleting agent. Agriculture and forestry in peatlands are the main sources of N2O emissions. Climate extreme events may boost the emissions but knowledge on their effect is scarce. N2O is a product of a variety of soil processes, including denitrification, nitrification and less studied mechanisms. Partitioning of N2O fluxes between all these different mechanisms is still a major challenge. Microbial processes are of particular importance for N2O budgets. The role of canopy and tree stems in N2O budgets is currently unknown. Novel flux measurement techniques implemented at different levels in combination with remote sensing methods can provide a solid basis for adequate estimation of long-term N2O fluxes in peatlands from local to the global scale. The ground-breaking nature of the proposal lies in integrated use of a combination of innovative methods yielding a pioneering synthesis and modelling of nitrous oxide fluxes at various spatial scales, linked to microbial processes. PeatlandN2O project will: (1) determine the role of rapidly changing environmental factors (soil moisture, freeze–thaw, canopy effects) on N2O emission, particularly in hot spots and hot moments; (2) distinguish between and quantify key N2O production and consumption processes using labelled nitrogen, isotopologues, and microbiome structure; (3) integrate results of experiments and novel measurement techniques (automated chambers, stationary and mobile eddy covariance towers, canopy profile analysis) into the PEATN2O model of N2O fluxes and related environmental factors to enable prediction of hot spots and hot moments of N2O emissions; (4) upgrade IPCC emission factors and suitable land-use strategies to mitigate N2O emissions in peatlands, also considering other greenhouse gases; (5) predict global distribution of N2O emissions according to the land-use and 5 climate change scenarios for 100-year time horizon.