## 1 Introduction  
Mangroves are now widely valued and increasingly recognized for their contributions to human society. On the one hand, they can provide ecological services and economic value, such as coastal protection, water purification, and fish biomass production [1, 2]. Furthermore, mangroves have the capability to sequester carbon at very large rates per unit area [3, 4]. The mean global burial rate of mangroves is 174 g C m\({}^{-2}\) y\({}^{-1}\), which is triple to tenfold that of other ecosystems [5]. However, their anoxic environment generates CH\({}_{4}\) emissions from mangroves, which partially offset \"blue carbon\" burial in mangroves [6].  
The CO\({}_{2}\) and CH\({}_{4}\) fluxes between the atmosphere and biosphere from mangroves depend on photosynthesis, autotrophic and heterotrophic respiration, and the microbial methanogenic processes [7; 8]. Similar to other tropical forests, these processes are greatly influenced by climate factors such as temperature, precipitation, radiation, etc. For example, the temperature regulates stomatal conductance and microbial activity that strongly affect photosynthesis [9], mineralization, and methanogenesis [10]. Precipitation changes the inundation period and indirectly influences the organic matter decomposition [11]. The radiation determines the amount of light available for photosynthesis [12]. Additionally, since mangroves are distributed in coastal tropical and subtropical regions, their carbon fluxes also respond to tidal amplitude [13], salinity [14], and nutrient availability [15].  
Mangroves not only support numerous ecosystem services, including fisheries production and nutrient cycling, but also sequester carbon that is disproportionate to their area. As one of the effective natural climate solutions to achieve carbon neutrality [16], mangrove conservation and mangrove restoration have long been recognized by national governments through international agreements. The Chinese mangrove area has increased from 18,602 ha to 28,010 ha from 2000 to 2020, becoming one of the few countries in the world with a net increase in mangrove areas [17; 18]. The Mangrove Protection and Restoration Action Plan (2020-25) (MPRAP) issued by China's Ministry of Natural Resources and the National Forestry and Grassland Administration states that China will restore 9050 ha of mangrove forests, a quarter of which will be carried out in Guangdong Province.  
Guangdong Province has the largest mangrove area in China [17]. Many mangrove wetland parks have been established in Guangdong Province since it is a direct and effective way to expand mangrove areas. Mangroves were restored or replanted along open water in these parks. The carbon budgets of mangrove parks are not only influenced by the above climate and environmental factors, but are also related to the recovery period and method, biophysical conditions [19; 20], and the proportion of vegetation and open water area [21]. The carbon fluxes from artificially restored mangrove parks have been far less studied than those from natural mature mangroves in China [13; 14; 22; 23; 24; 25]. It is urgent to estimate the carbon budget due to mangrove restoration to better understand their potential contribution to carbon neutrality on regional or national scales [26].  
In this study, we used EC measurements to observe CO\({}_{2}\) and CH\({}_{4}\) exchanges from a mangrove park having a 12-year restoration period located in Guangzhou, Guangdong Province, China. We analyzed the long-term measurements of CO\({}_{2}\) sequestration by plants, CO\({}_{2}\) release from plants, open water, and soil respiration, as well as CH\({}_{4}\) emissions. The primary objectives were (1) to characterize the temporal variations in CO\({}_{2}\) and CH\({}_{4}\) fluxes and (2) to reveal the response of carbon fluxes to biophysical drivers.