Greenhouse gases (GHGs) trapped in ice wedges may provide useful information on biogeochemical environments in ground ice. Previous studies have reported highly elevated CO 2 and CH 4 mixing ratios in ice wedges. However, N 2 O mixing ratios in ice wedges remain unknown. Here, we present CO 2 , CH 4 and N 2 O mixing ratios in bubbles and plausible mechanisms of GHG formation for two lakeside ice wedges at Cyuie village near Yakutsk. The CO 2 gas age corresponds to the Last Glacial Maximum (18–19 ka). The δ(N 2 /Ar) values and bubble shapes indicate that the ice wedges formed by dry snow compaction rather than snowmelt water refreezing, while the δ 18 O and δD values of the ice indicate changes in the source area location and/or the climate during the Last Glacial Maximum. Using a dry extraction method, we obtained gas mixing ratios of 7–13% CO 2 , 5–130 ppm CH 4 and 100–5000 ppb N 2 O. The δ(O 2 /Ar) values imply that most of the O 2 was consumed by biological respiration. The CH 4 is negatively correlated with N 2 O and CO 2 . The N 2 O might have inhibited CH 4 production.
Bibliographical noteFunding Information:
Sampling and transporting work was supported by members of the Melnikov Permafrost Institute, Russian Academy of Science. CO2 measurements at Seoul National University were assisted by Heejung Kwak. Financial support was provided by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (NRF‐2018R1A5A1024958).
© 2019 John Wiley & Sons, Ltd.
All Science Journal Classification (ASJC) codes
- Earth-Surface Processes