Vapor pressure deficit plays a pivotal role in the carbon dioxide sink of the Jingxin Wetland

Abstract. Large uncertainties exist in the carbon sink and energy balance of wetland ecosystems under climate change conditions. This can be attributed, in part, to the limited understanding of the simultaneous impact of climate and carbon dynamics as well as that of energy equilibria. In addition, the temporal patterns and interconnections of carbon dynamics and energy equilibria, as inferred from ground observations, remain ambiguous. In this study, carbon dioxide flux data of the Jingxin Wetland from August 2021 to August 2023 were analyzed to evaluate the relative influence of climate change on the net ecosystem exchange (NEE) and energy equilibrium. The findings demonstrate that the Jingxin Wetland has a formidable capacity for carbon sequestration. Furthermore, the vapor pressure deficit (VPD) emerged as a key determinant of ecosystem carbon flux, whereas latent heat flux (LE) serves as the primary consumer of net radiation. Throughout the research period, net radiation (Rn) accounted for 73.5 % of the total radiation. During both vegetation growth and dormancy seasons, Rn emerged as a principal factor influencing LE, which in turn affected the state of carbon cycling in the wetland ecosystems by impacting variations in the VPD during the growing season. Overall, our research outcomes shed light on the interplay between climate, carbon cycles, and energy budgets in wetland ecosystems, offering valuable insights for future investigations and conservation endeavors.