## 5 Conclusions  
This study analyzed the CO\({}_{2}\) flux variation characteristics and the factors affecting them in the Momoge salt marsh ecosystem. During the growing season, we observed an initial decline and a subsequent increase in the daily variations in CO\({}_{2}\) fluxes in the Momoge salt marsh, with uptake occurring during the day (negative values) and release taking place at night (positive values). Two patterns emerged (one peak and two peaks), with reduced carbon absorption during midday due to light saturation resulting in a midday depression phenomenon for the latter pattern. Within each annual variation, the carbon fluxes in the study area roughly exhibited a \"V\" shape. The carbon fluxes during the non-growing season predominantly showed positive values, indicating the release of CO\({}_{2}\) into the atmosphere. The carbon sequestration intensities of the Momoge salt marsh ecosystem were 206.94 g CO\({}_{2}\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 500.28 g CO\({}_{2}\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 436.00 g CO\({}_{2}\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), and 358.61 g CO\({}_{2}\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\) for the years 2015-2017 and 2021, respectively. This indicates that the system behaves as a carbon sink.  
At both the hourly and daily scales, PAR was the primary factor affecting daytime variations in NEE during the growing season, while temperature was the main factor influencing nighttime NEE dynamics. At the daily scale, Tair, Tsoil, PAR, PPT, and WL all showed significant effects on net CO\({}_{2}\) exchange. At the monthly scale, larger values of Tsoil, Tair, PAR, and AGB corresponded to a stronger carbon absorption capacity of the ecosystem. As the WL rose, the proportion of plants exposed to the surface decreased, leading to a reduction in the wetland's carbon absorption capacity. Although the WL conditions significantly influenced the uptake and release of CO\({}_{2}\) in the ecosystem, temperature remained the primary factor for carbon fluxes in the Momoge salt marsh.  
Conceptualization, Q.M. and H.Y.; methodology, C.Z. and W.L.; software, M.Y.; data curation, L.C. and F.Y.; formal analysis, W.L.; writing--original draft preparation, Q.M.; writing--review and editing, L.C. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the Natural Science Foundation of Jilin Province of China (YDZJ202301 ZYTS235), a development project of the Jilin Province Forestry Department (2022-001), and research projects of the Jilin Province Public Welfare Research Institute (GY-2022-13 and GY-2023-10).  
**Data Availability Statement:** All data included in this study are available upon request by contacting the corresponding author.  
**Acknowledgments:** We express our gratitude to Jilin Province Jidian Electricity Distribution and Trading Co., Ltd. and Hainan Salan Low-Carbon Investment Co., Ltd. for their support of the development project of the Jilin Province Forestry Department (2022-001). We thank [PERSON], [PERSON], and [PERSON] for preparing the conditions to perform this study.  
**Conflicts of Interest:** The authors declare no conflict of interest.