Physicochemical properties and carbon cycle of soil on the intertidal mud flat to the north of the Yangtze Estuary

Soil samplings and field monitoring were conducted to investigate CO₂ fluxes properties on the interface of soil-atmosphere on intertidal zones to the north of the Yangtze Estuary. The net CO₂ flux values indicated that the mud flat performed generally as a carbon sink. The low tidal flat (point III) was observed having the greatest CO₂ flux where the higher Chl-a content brought stronger CO₂ sequestration, and the lower TOC content led to less CO₂ release in the processes of soil respiration and mineralization. In addition, groundwater level was studied as another critical factor of carbon cycle which had negatively correlated with CO₂ net fluxes. The results provide a better understanding on restoring and protecting coastal wetlands and present an important opportunity for mitigating greenhouse gas emissions.