Collaborative Research: Atmospheric time series of O2/N2, Ar/N2, CO2, and CO2 isotopic composition at Arctic background sites

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

This project continues a multi-generational atmospheric observing system that is tracking large-scale changes in Arctic marine and terrestrial biogeochemistry. The investigators will measure key carbon and oxygen cycle tracers that have large-scale significance because the atmosphere tends to mix rapidly, integrating flux signals over large areas. The regular collection and analysis of flask samples at three Arctic sites (Cold Bay, Alaska; Utqiaġvik, Alaska; and Alert, Nunavut, Canada) will continue time series of 1) atmospheric CO2 concentration, which resolves large changes in seasonal CO2 cycling related to changes in terrestrial photosynthesis, respiration, and carbon storage; 2) the isotopic composition of CO2, which provides insights into large-scale linkages between water and carbon, such as shifts in leaf-level water-use efficiency; and 3) the ratios of O2/N2 and Ar/N2, which help quantify the magnitude of the seasonal air-sea exchanges of O2 and heat as key indicators of ocean biogeochemical change. Collectively, these data serve as key indicators of large-scale ecological changes, land and ocean carbon sinks, and carbon-climate feedbacks. The data generated by this project will be freely available to the scientific community and the public. This project will train undergraduate and graduate students and leverage international collaborations for improved observing of Arctic Ocean biogeochemical change. Flask samples from each of the three stations will be analyzed for O2/N2 ratio and CO2 concentration. Additional flask samples at Alert and Utqiaġvik will be analyzed for the 13C/12C ratio and 18O/16O ratio of CO2. The project also supports in situ measurements of atmospheric O2/N2 at Utqiaġvik, which began in 2021, and a new in situ O2/N2 measurement system at Alert. The in situ measurements at Utqiaġvik and Alert address the need for better monitoring of the Arctic Ocean by resolving synoptic-scale fluctuations in O2/N2, driven by air-sea O2 fluxes from the Arctic Ocean, which are not well captured in more sparsely sampled flask data. These two installations, combined with a third installation at Svalbard run by the National Institute of Polar Research, Japan, can potentially yield the data necessary for high fidelity monitoring of O2 fluxes over a large portion of the Arctic Ocean. 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.