Interannual characteristics and driving mechanism of CO2 fluxes during the growing season in an alpine wetland ecosystem at the southern foot of the Qilian Mountains

作者：Jingbin Zhu, Hongqin Li, Huidan He, Fawei Zhang, Yongsheng Yang, Yingnian Li · 发表于：Frontiers in Plant Science · 年份：2022 · DOI：10.3389/fpls.2022.1013812 · 被引用次数：13 · 研究领域：Plant Water Relations and Carbon Dynamics、Peatlands and Wetlands Ecology、Atmospheric and Environmental Gas Dynamics

The carbon process of the alpine ecosystem is complex and sensitive in the face of continuous global warming. However, the long-term dynamics of carbon budget and its driving mechanism of alpine ecosystem remain unclear. Using the eddy covariance (EC) technique—a fast and direct method of measuring carbon dioxide (CO 2 ) fluxes, we analyzed the dynamics of CO 2 fluxes and their driving mechanism in an alpine wetland in the northeastern Qinghai–Tibet Plateau (QTP) during the growing season (May–September) from 2004–2016. The results show that the monthly gross primary productivity (GPP) and ecosystem respiration (Re) showed a unimodal pattern, and the monthly net ecosystem CO 2 exchange (NEE) showed a V-shaped trend. With the alpine wetland ecosystem being a carbon sink during the growing season, that is, a reservoir that absorbs more atmospheric carbon than it releases, the annual NEE, GPP, and Re reached −67.5 ± 10.2, 473.4 ± 19.1, and 405.9 ± 8.9 gCm -2 , respectively. At the monthly scale, the classification and regression tree (CART) analysis revealed air temperature (Ta) to be the main determinant of variations in the monthly NEE and GPP. Soil temperature (Ts) largely determined the changes in the monthly Re. The linear regression analysis confirmed that thermal conditions (Ta, Ts) were crucial determinants of the dynamics of monthly CO 2 fluxes during the growing season. At the interannual scale, the variations of CO 2 fluxes were affected mainly by precipitation and th...