Greenhouse gas formation in ice wedges at Cyuie, central Yakutia

Abstract

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.

Past climate and continentality inferred from ice wedges at Batagay megaslump in the Northern Hemisphere's most continental region, Yana Highlands, interior Yakutia

“…Unfortunately, no comprehensive modern precipitation stable-isotope data are available for the Yana Highlands. The nearest sites with available data are Zhigansk, about 500 km to the west (Kurita, 2011); Tiksi, about 500 km to the northwest (Kloss, 2008); and Yakutsk, about 650 km to the south (Kloss, 2008;Papina et al, 2017). These sites show similar isotopic characteristics for the cold season (October to March).…”

Brief Communication: The reliability of gas extraction techniques for analysing CH<sub>4</sub> and N<sub>2</sub>O compositions in gas trapped in permafrost ice wedges

“…Katayama et al, 2007), it is likely that culturable microbes exist in the ice-wedge samples used in this study. However, considering that at least 14 d and up to 3 months of culturing was required to identify microbe colonies extracted from ground ice (Katayama et al, 2007;Lacelle et al, 2011), our melt-refreeze time of an hour was insufficient for microbial activity to resume production of CH 4 and N 2 O.…”

“…The gases trapped in ground ice allow unique insights into the origin of ground ice and evidence for in situ microbial aerobic and anaerobic respiration (Boereboom et al, 2013;Kim et al, 2019;Lacelle et al, 2011). Among others, the GHGs in ground ice may provide detailed information on in situ biogeochemical processes responsible for GHG production (i.e.…”

Winter air temperature during the Holocene optimum in the north‐eastern part of the east European plain based on ice wedge stable isotope records

“…Fractionation during evaporation, sublimation, hoar development and melting–freezing is known to alter the primary isotope composition of material that fills the frost cracks. As a result, modern ice wedges are isotopically enriched relative to local winter precipitation, and a co‐isotope δ 2 H–δ 18 O diagram for the ice will deviate from the global meteoric water line (GMWL) and local meteoric water line (LMWL), which represent unaltered meteoric moisture …”

“…The most reliable reconstruction of the environmental conditions prevailing during ice wedge growth is provided by a multiparametric approach including ice crystallography, bubble content, gas composition and stable water isotopes …”