Soil N2O emissions from the Canadian boreal to Neotropical forests

This proposal is for a nitrous oxide (N2O) trace gas analyzer survey system for remote field research, that will be used to understand soil N2O emissions in two key biomes: Canadian boreal forests, an unresolved and potentially significant N2O source, and Neotropical forests, the largest N2O source globally. N2O is a potent greenhouse gas with a global warming potential 265 times that of carbon dioxide (CO2). Because of the challenges associated with their measurement, soil N2O emissions in natural ecosystems have been identified as a critical uncertainty in global greenhouse gas budgets with implications for understanding their contribution to climate change. Trace gas analyser survey systems (TGASS) offer significant advantages for measuring soil N2O fluxes over the conventional method - the static flux chamber method, which is imprecise, time-consuming, and inflexible. The TGASS provides instantaneous measurements of soil N2O fluxes, enabling sampling frequencies that generate comprehensive and robust estimates of soil N2O fluxes. The TGASS eliminates methodological biases introduced by the long sampling period of the static flux chamber method. The TGASS does not involve gas sample collection and processing which enables adaptive sampling strategies and remote field research. Furthermore, the N2O trace gas analyser will be paired to a CO2 and CH4 trace gas analyser to capture a complete greenhouse gas budget. The TGASS is essential for the research programmes of both applicants because of its state-of-the-art ability to take instantaneous and highly precise measurements of soil N2O fluxes (as well as CO2 and CH4 fluxes) and its suitability for remote field research. This will be the first setup of its kind at a Canadian academic institution and will pioneer Canadian university infrastructure to further research on soil N2O fluxes. The equipment will be used 100% of the time. Dr. Kou-Giesbrecht's research group will use the equipment from May through August, which is the active season for Canadian boreal forests. Dr. Soper will use the equipment from September through April, which spans the wet and dry seasons for Neotropical forests. By deploying the TGASS in two ecosystems with non-overlapping annual sampling seasons, the applicants will be able to maximize the effective value of the equipment. The feasibility of using the equipment is supported by the applicants’ extensive experience in measuring soil N2O fluxes and their excellence in research in this area. The TGASS is essential for advancing research on soil N2O fluxes in these two key ecosystems - Canadian boreal forests and Neotropical forests. It is critical to constraining uncertainty in the estimate of the N2O source from soils in natural ecosystems and its influence on climate change. This project will benefit both the Canadian scientific community as well as international efforts to mitigate climate change.