A 60-year atmospheric nitrate isotope record from a Southeast Greenland ice core with minimal post-depositional alteration

• Main Authors: Wei, Zhao, Hattori, Shohei, Tsuruta, Asuka, Jiang, Zhuang, Ishino, Sakiko, Fujita, Koji, Matoba, Sumito, Geng, Lei, Lamothe, Alexis, Uemura, Ryu, Yoshida, Naohiro, Savarino, Joel, Iizuka, Yoshinori
• Format: Text
• Language: English
• Published: 2024
• Subjects: Greenland; Greenland ice core; ice core
• Online Access: https://doi.org/10.5194/egusphere-2024-3937; https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3937/

Stable isotopes of atmospheric nitrate (NO 3 − ) are valuable tools for tracing nitrogen sources and processes; however, their signals in ice core records are often disrupted by post-depositional processes. The ice core from the southeastern Dome (SE-Dome) in Greenland is a potential record of variations in atmospheric chemistry that has experienced less post-depositional effects owing to a high accumulation rate (~1 m w e a −1 ). Herein, we report 60-year (1959–2014) δ 15 N(NO 3 − ) and Δ 17 O(NO 3 − ) records from the SE-Dome ice core. δ 15 N(NO 3 − ) decreased from 1960 to 1974 and exhibited clear seasonal changes (high in summer and low in winter). Δ 17 O(NO 3 − ) did not exhibit any significant long-term trends, but did contain seasonal patterns. The mass-weighted annual average of δ 15 N(NO 3 − ) values in the SE-Dome core were 4.2 ± 2.8 ‰ lower than those in the Greenland Summit ice core between 1959–2006. The Transfer of Atmospheric Nitrate Stable Isotopes To the Snow (TRANSITS) model under the SE-Dome condition estimated changes of only 0.9 ‰ in δ 15 N(NO 3 − ) and −0.2 ‰ in Δ 17 O(NO 3 − ) from the initial deposition. Although differences in the source of NO 3 − cannot be discounted, the lower δ 15 N(NO 3 − ) values observed at the SE-Dome compared to the Summit were likely due to reduced post-depositional alteration. Therefore, the SE-Dome ice core NO 3 − record offers a precise reconstruction of NO x emissions and atmospheric oxidation chemistry during transport, preserving records from both North America and Western Europe, thereby providing reliable insight into atmospheric nitrogen cycling.