Spatial and seasonal variations of atmospheric N2O and CO2 fluxes from a subtropical mangrove swamp and their relationships with soil characteristics
作者单位：Department of Biology and ChemistryCity University of Hong Kong
会议名称：《中国第五届红树林学术会议》
会议日期：2011年
关 键 词：Global warming Greenhouse gases Mai Po mangrove Nitrification-denitrification
摘 要：Marine ecosystems are known to constitute a net source of greenhouse gases emission but the atmospheric gas fluxes, particularly from the mangrove swamps occupying inter-tidal zones are poorly characterized. Spatial and seasonal fluxes of N2O and CO2 from soil in Mai Po mangrove swamp in Hong Kong, South China and their relationships with soil characteristics were investigated. The N2O fluxes averaged from 0.73 to 12.13 μmol m-2 h-1 and the CO2 fluxes were between 0.38 and 31.23 mmol m-2 h-1. Both N2O and CO2 fluxes showed large spatial and seasonal variations in this swamp. The fluxes were higher at the landward site than the fore shore bare flat and higher fluxes were recorded in warm than cold seasons. The landward site had the highest content of soil organic carbon （OC）, total Kjeldahl nitrogen （TKN）, nitrate （NO3--N） and total phosphorus （TP） while the bare flat had the highest ammonium nitrogen （NH4+-N） concentration and soil denitrification potential activity. The N2O flux was positively related to CO2 flux, and both gases fluxes were positively related to redox potential, OC, and TP, negatively related to NH4+-N but the correlations with either potential nitrification or denitrification activities in soil were not significant. Stepwise analysis results indicated that the N2O emission was probably due to soil denitrifcation processes.