Study On The Soil CH₄and CO₂Fluxes Of Mangrove Communities In Yingluo Bay, Guangxi

The natural conservation area of Yingluo Bay of Guangxi is one of the important natural mangrove wetland reserves in China. Here are suitable for the growth of mangroves just as Kandelia candel, Bruguiera gymnorrhiza, RhizopHora stylosa and Aegiceras corniculatum.In recent years, emissions of methane and carbon dioxide and other greenhouse gases in the wetlands has also been widespread concern of the academia. In this paper, we studied the characteristics of soil CO2and CH4emission fluxes of the main mangrove communities in Yingluo Bay, and the relationship between the soil CO2and CH4emission fluxes and their environmental factors were also anlyzed by using the WEST-1011portable soil measuring instrument in Spring (March), Summer(July) and Autumn (September). The results were as follows:(1) In Spring, the daily mean soil CH4fluxes of Kandelia candel community, Bruguiera gymnorrhiza community, RhizopHora stylosa community and Aegiceras corniculatum community were0.459μmol·m-2·s-1,1.707μmol·m-2·s-1,0.722μmol·m-2·s-1and0.870μmol·m-2·s-1. Their daily mean soil CO2fluxes were2.436μmol·m-2·s-1,2.359μmol·m-2·s-1,1.071μmol·m-2·s-1and6.536μmol·m-2·s-1。(2) In Summer, the daily mean soil CH4fluxes of Kandelia candel community, Bruguiera gymnorrhiza community, RhizopHora stylosa community and Aegiceras corniculatum community were0.301μmol·m-2·s-1,-0.003μmol·m-2·s-1,0.012μmol·m-2·s-1and0.081μmol·m-2·s-1.Their daily mean soil CO2fluxes were65.414μmol·m-2·s-1,3.684μmol·m-2·s-1,15.803μmol·m-2·s-1and2.529μmol·m-2·s-1。(3)In Autumn, the daily mean soil CH4fluxes of Kandelia candel community, Bruguiera gymnorrhiza community and Aegiceras corniculatum community were0.710μmol·m-2·s-1,0.706μmol·m-2·s-1,3.235μmol·m-2·s-1.Their daily mean soil CO2fluxes were3.633μmol·m-2·s-1,320.707μmol·m-2·s-1and3.305μmol·m-2·s-1。(4) In the seasonal dynamics, CH4fluxes of various communities in Summer was minimum compared to other seasons. In Spring, CH4fluxes of each community changed little. There was difference of CH4fluxes among Kandelia candel, Bruguiera gymnorrhiza and Aegiceras corniculatum community. In Autumn, there were significant changes in CO2fluxes of each community. CO2fluxes of Bruguiera gymnorrhiza and Aegiceras corniculatum communities changed little in Spring and in Summer. CO2fluxes of Kandelia candel and RhizopHora stylosa communities in Summer had been greatly improved compared to in Spring.(5) Results showed that air temperature has remarkable correlation with soil CH4and CO2fluxes of Aegiceras corniculatum community, and soil pH has great influence on the CH4fluxes of RhizopHora stylosa and Aegiceras corniculatum communities.