Arid Zone Research ›› 2022, Vol. 39 ›› Issue (3): 754-766.doi: 10.13866/j.azr.2022.03.09

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Precipitation gradient influence on daily greenhouse gas emission fluxes from a Qinghai Lake wetland

YANG Ziwei1,2,3(),CHE Zihan2,3,LIU Fumei1,2,3,CHEN Kelong2,3()   

  1. 1. School of Geographical Sciences, Qinghai Normal University, Xining 810008, Qinghai, China
    2. Key Laboratory of Natural Geography and Environmental Processes of Qinghai Province, Xining 810008, Qinghai, China
    3. Key Laboratory of Qinghai-Tibet Plateau Surface Process and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, Qinghai, China
  • Received:2021-09-09 Revised:2021-11-22 Online:2022-05-15 Published:2022-05-30
  • Contact: Kelong CHEN E-mail:1041730364@qq.com;ckl7813@163.com

Abstract:

Moisture is the main limiting factor affecting the growth and development of alpine ecosystems. To explore effects of different water conditions on characteristics of greenhouse gas emissions from wetlands, wetlands at the source of the Wayan Mountain in Qinghai Lake Basin were selected. Box-gas chromatography monitored 24-hour greenhouse gas emission characteristics of wetlands and explored effects of control treatment (CK), +25% (precipitation increase 25% treatment), -25% (reduction in the daily change trend of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) under conditions of 25% rain treatment), +75% (precipitation increaseo of 75% treatment), and -75% (precipitation reduction of 75% treatment). The results showed that: (1) CO2 emission ranged from 47.52 to 123.71 mg·m-2·h-1, CH4 flux ranged from -8.50 to 6.74 µg·m-2·h-1, and N2O flux ranged from -15.82 to 6.90 µg·m-2·h-1. (2) The diurnal variation of CO2, CH4 and N2O in CK, +25% and +75% treatments showed emission status, and the diurnal variation of CO2 in -25% treatment showed emission status, while CH4 and N2O showed absorption status; The diurnal changes of CO2 and N2O under -75% treatment were emission state, while CH4 was absorption state, and there were significant differences among different precipitation treatments (P<0.05). (3) CO2 had a significant positive correlation with soil temperature (P<0.05) and a significant negative correlation with soil moisture (P<0.05); There was a significant negative correlation between CH4 and soil temperature (P<0.05) and between CH4 and soil moisture (P<0.05); There was a positive correlation between N2O and soil temperature (P<0.05), while there was a negative correlation between N2O and soil moisture in CK treatment and a positive correlation in rain reduction treatment (P<0.05), and there was no obvious regularity. (4) Small succession of plant communities occurred under different water treatments. The balance of soil moisture and temperature has a significant impact on the greenhouse gas emission flux in this area, and the imbalance should be avoided to lead to the increase of greenhouse gas emissions.

Key words: greenhouse gas, static chamber-gas chromatography, source-sink effect, soil moisture, precipitation simulation, Qinghai Lake