5. CONCLUSIONS
Our results indicated that the alpine wetland in this study was a weak carbon source. Our findings indicate that aggregated growing season degree day and soil temperature were the most important controlling factors for the seasonal variations of CO2 fluxes. The hydrothermal conditions especially during the non-growing season played an important role in determining inter-annual variations of CO2 fluxes. The results of our study highlighted the importance of the non-growing season CO2 emissions for the variation of CO2 dynamics, which was few focused by previous studies. According to our study results, we speculate that under the context of global warming, especially in the non-growing seasons, which will exacerbate carbon loss in the alpine wetlands of the QTP.
Our alpine wetland was a carbon source, which agrees well with the earlier reports. However, the swamps in Northern Tibetan Plateau (NTP) and Qinghai Lake (QL) are strong carbon sink (Cao et al., 2017; Niu et al., 2017). The stronger GPP in NTP and lower RES in QL accounted for the discrepancy, respectively. Our results showed that the estimation of carbon sequestration capacity of alpine wetland should be more cautious.