## 3 Results
### Ecosystem CO\({}_{2}\) Balances  
The dynamics of ecosystem CO\({}_{2}\) exchange were closely linked to climate conditions and vegetation, displaying significant seasonal and interannual variations. The ecosystem acted as a carbon sink during the growing season (May-October) and as a carbon source during the non-growing season (December-April) (Figure 10).  
Figure 10: Seasonal dynamics of monthly mean net ecosystem carbon exchange (NEE) in the Momoge salt marsh. Different lowercase letters indicate significant difference (\(p<0.05\)) among different years in the same month, ns indicates no significant difference.  
The four distinct seasons of the climatic conditions and vegetation in the Momoge salt marsh led to noticeable variations in the CO2 flux of the wetland ecosystem. This could be observed in the average daily data for each month. By calculating the daily average CO2 flux for each month from 2015 to 2017 and in 2021, a monthly average CO2 flux graph was generated. As shown in Figure 8, the monthly average CO2 flux was positive from January to April and from October to December. This indicates that the ecosystem emitted CO2 to the atmosphere, acting as a carbon source. In May, as needs started to sprout, photosynthesis intensified and the amount of CO2 absorbed by needs gradually increased. From June to September, the wetland entered its growing season, and the monthly average carbon flux values were negative. July marked the peak, where the ecosystem absorbed CO2 from the atmosphere. During this period, the reed wetlands exhibited significant carbon sink activity during the day. Subsequently, as the reeds entered the senescence phase, the amount of absorbed CO2 decreased, and the system shifted back to emitting carbon. Overall, within the study period, the wetland ecosystem exhibited its strongest carbon sequestration capacity in July, with a minimum monthly cumulative carbon flux of up to \(-\)359.98 g CO2\(\cdot\)m\({}^{-2}\)(July 2021). On the other hand, the month of January had the highest carbon emissions to the atmosphere, with a maximum monthly cumulative carbon flux of 185.89 g CO2\(\cdot\)m\({}^{-2}\)(October 2015). The CO2 flux differed significantly among the different months in each year, with the CO2 flux values from June to September notably lower than those in the other months (F = 29.79, \(p<0.001\)).  
The NEE monitoring over the four years in the Momoge salt marsh revealed that it functions as a carbon sink overall. The carbon sequestration intensities for each year were as follows: 206.94 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 500.28 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 436.88 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), and 358.61 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\) in 2015, 2016, 2017, and 2021, respectively. The cumulative GPP values were \(-\)1152.62 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), \(-\)1928.62 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), \(-\)1516.79 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), and \(-\)1409.74 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\). The cumulative Reco values were 945.68 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 1428.34 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), 1079.91 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), and 1051.13 g CO2\(\cdot\)m\({}^{-2}\cdot\)yr\({}^{-1}\), respectively.