Song Liquan, Zang Shuying, Lin Lin, Lu Boquan, Sun Chaofeng, Jiao Yaqing, Wang Hanxi
Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin, 150025, China.
Heilongjiang Province Collaborative Innovation Center of Cold Region Ecological Safety, Harbin, 150025, China.
Environ Sci Pollut Res Int. 2022 May;29(21):31700-31712. doi: 10.1007/s11356-022-18545-z. Epub 2022 Jan 11.
Climate warming has intensified changes of permafrost freeze-thaw process and postponed the starting period of soil freezing, which significantly affected the processes of NO production and emission from the soils. However, responses of soil NO fluxes to freeze-thaw cycles (FTC) during autumn freezing period in permafrost peatlands in field remain unclear. Therefore, the static chamber-GC techniques were used to explore the effects of autumn FTC on NO fluxes in the three permafrost peatlands [Calamagrostis angustifolia peatland (CA), Larix gmelini-Sphagnum swamp (LS), and Eriophorum vaginatum peatland (EV)] in Da Xing'an Mountains, Northeast China, from September to November 2019. The response peaks of NO fluxes to autumn FTC in CA (29.22 ± 14.90 μg m h) and EV (19.70 ± 7.26 μg m h) occurred in the autumn FTC prophase, whereas LS (11.33 ± 0.90 μg m h) appeared in the autumn FTC metaphase. CA (394.90 μg m) and EV (497.82 μg m) acted as a NO source, and LS (- 1321.43 μg m) was a NO sink. The effects of autumn FTC on NO fluxes were significantly different (p < 0.001) in the three permafrost peatlands. NO emissions during autumn FTC were mainly driven by soil NH-N, DOC content and soil NO-N content. The results implied that autumn FTC could stimulate soil NO emissions in permafrost peatlands and confirmed the important contribution of NO emissions during autumn FTC to annual nitrogen budget. This study could improve the accuracy of regional estimates of annual nitrogen budget.
气候变暖加剧了多年冻土冻融过程的变化，推迟了土壤冻结的起始期，这显著影响了土壤中一氧化氮（NO）的产生和排放过程。然而，多年冻土泥炭地秋季冻结期土壤NO通量对冻融循环（FTC）的响应在野外仍不清楚。因此，于2019年9月至11月，采用静态箱-气相色谱技术，探究了秋季FTC对中国东北大兴安岭地区3个多年冻土泥炭地[小叶章泥炭地（CA）、落叶松-泥炭藓沼泽（LS）和毛苔草泥炭地（EV）]中NO通量的影响。CA（29.22±14.90μg m h）和EV（19.70±7.26μg m h）中NO通量对秋季FTC的响应峰值出现在秋季FTC前期，而LS（11.33±0.90μg m h）出现在秋季FTC中期。CA（394.90μg m）和EV（497.82μg m）是NO源，LS（-1321.43μg m）是NO汇。秋季FTC对3个多年冻土泥炭地NO通量的影响存在显著差异（p＜0.001）。秋季FTC期间的NO排放主要受土壤铵态氮（NH-N）、溶解性有机碳（DOC）含量和土壤硝态氮（NO-N）含量驱动。研究结果表明，秋季FTC可刺激多年冻土泥炭地土壤NO排放，并证实了秋季FTC期间NO排放对年度氮收支的重要贡献。该研究可提高区域年度氮收支估算的准确性。
