EAGER: Testing the Galápagos as a long-term monitoring site for nitrous oxide emissions from the Pacific oxygen deficient zones

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Nitrous oxide is a potent greenhouse gas and agent of ozone destruction. Atmospheric concentrations are rising, but the role of natural marine sources is poorly understood due to a lack of data. High rates of oceanic production are localized to remote areas, impeding direct data acquisition from oxygen minimum zones especially. Correct attribution of sources is key to interpreting observations, establishing mitigation policies, and predicting future climate feedbacks. The investigators aim to quantify marine nitrous oxide fluxes through a continuous monitoring site in the eastern Pacific that can identify hotspots and mechanisms of production. Such a station will permit the ocean’s role in this greenhouse gas budget to be refined and its variability across space and time to be assessed. The data will be publicly accessible and maintained at a bilingual web portal in English and Spanish. The work will further educate and train a graduate student in oceanic and climate sciences and help establish an early career investigator.The project will establish an atmospheric chemistry monitoring station at the Galapagos Science Center in Ecuador to continuously measure nitrous oxide and carbon monoxide. The measurements will be linked specifically to ocean outgassing via atmospheric inversion modeling. This new methodology complements sea-going research, permitting the assessment of emissions across the entire eastern tropical Pacific Ocean region from a single well-sited monitoring station. The investigators will specifically deploy a cavity ring-down laser spectrometer onsite, maintain the instrument, and analyze the continuous data. By the end of this initial 2-year study, a multi-year record of primary atmospheric concentrations of nitrous oxide will be established and tied to emissions from specific ocean sources. The researchers will map the data via inversion modeling, paying particular attention to cross-shelf variability and any roles of sub-mesoscale eddies in modifying the rate of nitrous oxide loss from the ocean. Carbon monoxide will be utilized as a diagnostic molecule for terrestrial influence on nitrous oxide. Overall, this project will elucidate the emissions from a critical yet under-sampled production region and reduce the level of uncertainty in data products and modeled syntheses. These measurements will aid in interpreting global observations, ground-truth current and future sampling campaigns, and improve forecasting of climate scenarios into the future.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.