Acta Geographica Sinica ›› 2020, Vol. 75 ›› Issue (11): 2319-2331.doi: 10.11821/dlxb202011004

• Climate and Environment Change • Previous Articles     Next Articles

Greenhouse gas fluxes from forest soil in permafrost regions of Greater Hinggan Mountains, Northeast China

WU Xiangwen(), ZANG Shuying(), MA Dalong, REN Jianhua, LI Hao, ZHAO Guangying   

  1. Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, China
  • Received:2019-01-16 Revised:2020-09-04 Online:2020-11-25 Published:2021-01-25
  • Contact: ZANG Shuying E-mail:hsdwxw@163.com;zsy6311@163.com
  • Supported by:
    National Natural Science Foundation of China(41971151);National Natural Science Foundation of China(41501065);National Natural Science Foundation of China(41601382);Natural Science Foundation of Heilongjiang Province(TD2019D002);Doctoral Innovation Foundation of Harbin Normal University(HSDBSCX2019-02)

Abstract:

Greenhouse gases from permafrost have a significant impact on global climate change. The in situ static dark chamber and gas chromatography techniques were used to monitor the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous dioxide (N2O) from the typical forest soils of Larix gmelini, Pinus sylvestris, and Betula platyphylla in the permafrost regions of the Greater Hinggan Mountains. The experiment was conducted during the growing season (May to September) of 2016 and 2017. The dynamic characteristics of greenhouse gas fluxes and the controlling factors were comparatively analyzed. The results showed that soil CO2, CH4, and N2O fluxes of the three forest types were 65.88-883.59 mg·m-2·h-1, -93.29--2.82 μg·m-2·h-1, and -5.31-45.22 μg·m-2·h-1, respectively. The soils from the three typical forests were all sources for CO2 and N2O, and sink for CH4 during the entire observation period. Soil CO2 and CH4 fluxes changed significantly among different forest types and between the two observation periods. The soil CO2 fluxes of the three forest types were mainly controlled by soil temperature and were found to have a significantly positive correlation with the soil temperature at 5, 10, and 15 cm (P < 0.01). The soil CH4 fluxes were affected by soil water content and soil temperature. The correlations were significant in the soils at 10 and 15 cm (P < 0.05). Moreover, the air temperature controlled and regulated soil N2O fluxes. The soil N2O fluxes in the Betula platyphylla forest showed a significantly negative correlation with the soil temperature at 15 cm (P < 0.05). The emission rate of soil CO2 and N2O accelerated with increasing temperature, while the absorption rate of CH4 decreased, enhancing the atmospheric greenhouse effect. The global warming potential of greenhouse gases was calculated based on the 100-year time scale, where the soil greenhouse gases of the three forest types exhibited a positive feedback on climate warming.

Key words: greenhouse gas, permafrost, forest soils, global warming potential, Greater Hinggan Mountains