Rich soil carbon and nitrogen but low atmospheric greenhouse gas fluxes from North Sulawesi mangrove swamps in Indonesia

Abstract The soil to atmosphere fluxes of greenhouse gases N 2 O, CH 4 and CO 2 and their relationships with soil characteristics were investigated in three tropical oceanic mangrove swamps (Teremaal, Likupang and Kema) in North Sulawesi, Indonesia. Mangrove soils in North Sulawesi were rich in organic carbon and nitrogen, but the greenhouse gas fluxes were low in these mangroves. The fluxes ranged − 6.05–13.14 μmol m − 2  h − 1 , − 0.35–0.61 μmol m  − 2  h − 1 and − 1.34–3.88 mmol m − 2  h − 1 for N 2 O, CH 4 and CO 2 , respectively. The differences in both N 2 O and CH 4 fluxes among different mangrove swamps and among tidal positions in each mangrove swamp were insignificant. CO 2 flux was influenced only by mangrove swamps and the value was higher in Kema mangrove. None of the measured soil parameters could explain the variation of CH 4 fluxes among the sampling plots. N 2 O flux was negatively related to porewater salinity, while CO 2 flux was negatively correlated with water content and organic carbon. This study suggested that the low gas emissions due to slow metabolisms would lead to the accumulations of organic matters in North Sulawesi mangrove swamps.