187 / 2024-09-11 02:21:50

Continuous atmospheric nitrous oxide measurements quantify marine emissions variability in association with El Niño

nitrogen,Nitrous Oxide,oxygen minimum zones

Session 3 - The nitrogen cycle towards a sustainable ocean: from microbes to global biogeochemistry

Nitrous oxide is a biogenic gas critical in controlling stratospheric ozone chemistry and Earth’s greenhouse budget. Yet, classically, marine emissions have been overlooked due to the difficulty of sampling and the severe heterogeneity of production. Here, we present a new station in the Galapagos Islands continuously measuring nitrous oxide concentrations in the lower troposphere to infer its emissions from the surrounding surface ocean and land. By strategically locating our station in the eastern tropical Pacific, we quantify the spatial and temporal variability of emissions from waters around the Pacific’s oxygen minimum zones. From the station's first year of data, we have derived over 150,000 flux estimates across the region. Further, continuous measurement permits internannual and seasonal variability to be quantified, and we report a three-fold reduction of nitrous oxide emissions from the eastern tropical south Pacific oxygen minimum zone in association with the strong 2023 El Niño compared to a climatological best estimate.