Summer fluxes of atmospheric greenhouse gases N2O, CH4 and CO2 from mangrove soil in South China

The atmospheric fluxes of N2O, CH4 and CO2 from the soil in four mangrove swamps in Shenzhen and Hong Kong, South China were investigated in the summer of 2008. The fluxes ranged from 0.14 to 23.83 μmol m−2 h−1, 11.9 to 5168.6 μmol m−2 h−1 and 0.69 to 20.56 mmol m−2 h−1 for N2O, CH4 and CO2, respectively. Futian mangrove swamp in Shenzhen had the highest greenhouse gas fluxes, followed by Mai Po mangrove in Hong Kong. Sha Kong Tsuen and Yung Shue O mangroves in Hong Kong had similar, low fluxes. The differences in both N2O and CH4 fluxes among different tidal positions, the landward, seaward and bare mudflat, in each swamp were insignificant. The N2O and CO2 fluxes were positively correlated with the soil organic carbon, total nitrogen, total phosphate, total iron and NH4+-N contents, as well as the soil porosity. However, only soil NH4+-N concentration had significant effects on CH4 fluxes.