Nitrogen and oxygen isotopic constraints on the origin of atmospheric nitrate in coastal Antarctica

• Main Authors: Savarino, J., Kaiser, J., Morin, S., Sigman, D. M., Thiemens, M. H.
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Geosciences Princeton, Princeton University, University of California San Diego (UC San Diego), University of California (UC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarc*; Antarctic; Antarctica
• Online Access: https://hal.science/hal-00328011; https://hal.science/hal-00328011/document; https://hal.science/hal-00328011/file/acpd-6-8817-2006.pdf

International audience Throughout the year 2001, size-segregated aerosol samples were collected continuously for 10 to 15 days at the French Antarctic Station Dumont d'Urville (DDU) (66°40' S, l40°01' E, 40 m above mean sea level). The nitrogen and oxygen isotopic ratios of particulate nitrate at DDU exhibit seasonal variations that are among the most extreme observed for nitrate on Earth. Associated with a late winter increase in the concentration of particulate nitrate, d 18 O and ? 17 O reach as high as 111.5 versus VSMOW and 41.1, respectively. These are best explained as a signal of stratospheric input, with halogen radicals extracting 17O- and 18O-rich terminal oxygen from ozone and incorporating it into the nitrogen oxides, even if we are unable to reproduce this high ? 17 O value with the current knowledge of isotopic anomaly transfers during chemical reactions. This failure calls for the evaluation of polar ozone isotopic composition. During the late springtime peak in particulate nitrate, its d 15 N falls to -46.9 versus atmospheric N 2 , suggesting that this peak results from snow re-emission, which has been shown previously to enrich in d 15 N the retained nitrate fraction in continental Antarctic sites.