The Regular Pattern And Influence Factors Of GHG (Greenhouse Gas) Emissions From Mangrove Soil In Hainan Dongzhaigang

With concerns about global warming growing, The Greenhouse gases, especially methane(CH4) and carbon dioxide(CO2) emissions more and more be taken seriously,The study of greenhouse gas emissions also started in different fields.The mangrove of Dongzhai Harbor in Hainan is the most abundant species, the most complete preservation of the mangrove ecosystem in our country. This article selects four kinds of common mangrove community in the Dongzhai Harbor in Hainan, namely bruguiera sexangula community, Ceriops tagal community, Kandelia candel community, Sonneratia apetala community, and Tidal flats, seeting some sample areas to collect The Greenhouse Gases. continuous monitoring the rate of methane and Carbon Dioxide Emissions each soil sample from November 2013 to October 2014 through the year, comparison and analysis the rate to explore the regular pattern and influence factors of GHG(Greenhouse Gas) Emissions from Mangrove soil in Hainan Dongzhaigang Harbor. We sampling the soil CH4 fluxes in sample plot in situ using static box- gas chromatography in the experiments, and Using GC7890 A gas chromatograph to determine in the laboratory; Using LI-8100 A soil carbon flux automatic measuring instrument for in situ determination of soil CO2 flux in mangrove community and Calculating the rate emissions. Each type of samples to set up three groups of repeated samples, and each sample within the party set up four different treatment, including A processing( remove the root and litter at the same time)、B treatment(remove the root)、 C treatment(remove the litter)、D treatment(contrast). Simultaneous determination of soil temperature, air temperature, soil physical and chemical properties, including TN, TP, SOC, and litter and the decomposition rate of the litter and other factors, Analysis of the above factors and the correlation of between soil CH4、CO2 emission rate and those factors.The results showed that:(A) CO2 Emissions(1) The average of CO2 emission flux is 1.489 μmol · m-2 · s-1, which from the soil in the mangrove wetland throughout the year. The annual maximum peak of carbon dioxide emissions flux is 12.70μmol · m-2 · s-1 in the Sonneratia apetala community in June.(2) annual average of soil CO2 flux of Different communities size order: Sonneratia apetala community > Kandelia candel community > bruguiera sexangula community > Ceriops tagal community > Tidal flats, Its values were 3.9687μmol·m-2·s-1, 1.6879μmol·m-2·s-1, 1.3381μmol·m-2·s-1, 0.6709 μmol·m-2·s-1,-0.1842μmol·m-2·s-1, Tidal flats performance for absorb CO2 overall average. Significance of difference analysis shows that in addition to the CO2 emission flux show no significant differences(P > 0.05) between the Kandelia candel community and the bruguiera sexangula community, having significant difference(P < 0.05)between the Kandelia candel community and Ceriops tagal community,the CO2 emission flux showing significant differences(P < 0.01) between communities and tidal flats and between other communities and other communities.(3) Mangrove soil CO2 emissions throughout the year have larger emission flux in March to August, low emission and smooth flux in September to February; and the temperature(P < 0.01, R2 = 0.748), Mangrove soil CO2 emissions and soil temperature(P < 0.01, R2 = 0.204)were very significant positive correlation.(4) Each sample of mangrove soils in the A and B, C, D four processing between CO2 emission flux extremely significant difference(P < 0.01), the flux size order for A(remove the root and litter) > B(remove root) > C(remove litter) >D(contrast), the corresponding average 3.5828μmol·m-2·s-1,2.946μmol·m-2·s-1,2.1595μmol·m-2·s-1, 1.91μmol·m-2·s-1.In mangrove vegetation’s soil, destroy the roots,can lead to the soil by green plants before decomposition of fixed carbon from the atmosphere to be released into the atmosphere, resulting in the loss of soil carbon, the roots of the plant in the mangrove play an important role on soil carbon fixation and reduce the loss of soil carbon.(5) By comparing the differences of the artificial community(Sonneratia apetala community), natural community(bruguiera sexangula community, Kandelia candel community and Ceriops tagal community), the Tidal flats soil CO2 emissions, found that plantation > natural community > Tidal flats, the corresponding value is 3.9637μmol·m-2·s-1, 1.2323μmol·m-2·s-1,-0.1842μmol·m-2·s-1.as foreign introduced Sonneratia apetala community have its maximum soil CO2 emissions, significantly greater than the CO2 emissions of natural communities and Tidal flats(P < 0.01).The soil CO2 flux from Natural community significantly greater than the tidal flats(P < 0.01).(B) Methane Emissions(1) 、In terms of emissions of methane, mangrove soil methane emissions average of 0.56 μmol · m-2 · s-1 throughout the year.The methane emission value of 2.34 μmol · m-2 · s-1 peak appears in the September throughout the year in the Sonneratia apetala community.(2) 、The annual average of soil CH4 flux of Different communities size order: Ceriops tagal community >Sonneratia apetala community >Kandelia candel community>bruguiera sexangula community > Tidal flats, Its values were 0.6553μmol·m-2·s-1、0.5849μmol·m-2·s-1、0.5605μmol·m-2·s-1、0.4995μmol·m-2·s-1、0.4703μmol·m-2·s-1. Ceriops tagal community soil CH4 emission flux significantly larger than bruguiera sexangula community and Tidal flats,(P < 0.01).The difference soil CH4 emission flux between Kandelia candel community and Tidal flats was significant(P < 0.01). The soil CH4 emissions of Sonneratia apetala community significantly greater than the tidal flats soil CH4 emission fluxes(P < 0.05).The difference of soil CH4 emission fluxbetween Bruguiera sexangula community and Kandelia candel community was not significant(P > 0.05);The difference of soil CH4 emission fluxbetween Bruguiera sexangula community and Sonneratia apetala community was not significant(P > 0.05); The difference of soil CH4 emission flux between Kandelia candel community and Kandelia candel community was not significant(P > 0.05).(3)、The CH4 emissions present trends to increase volatility throughout the year.The CH4 emission is mainly decided by soil temperature in May. The CH4 emission is mainly by typhoons bring a lot of litter in July and the influence of litter decomposition rate for the whole year, September methane emissions is caused by long time flooded caused by anaerobic respiration increase; Soil temperature and methane emissions was significantly correlated(P < 0.05, R2 = 0.183).(4)、Four mangrove community soil sample in four different treatment of soil CH4 emission flux size order for A(go root litter) > D(unprocessed) > B(to) > C(to litter), and its corresponding value is 0.5868μmol·m-2·s-1, 0.5926 μmol·m-2·s-1, 0.545μmol·m-2·s-1, 0.4618μmol·m-2·s-1. The soil CH4 emission difference of treatment A and D respectively and between B and C processing were significantly(P < 0.01), the soil CH4 emission difference between B and C processing were significantly(P < 0.01).(5)、By comparing the differences of the artificial community(Sonneratia apetala community), natural community(bruguiera sexangula community, Kandelia candel community and Ceriops tagal community), the Tidal flats soil CH4 emissions, found that soil CH4 emission size order for natural community > artificial community > tidal flats, the corresponding value is 0.5863μmol·m-2·s-1, 0.5711μmol·m-2·s-1, 0.4687 μmol·m-2·s-1. N significant difference between natural community and artificial communities(P > 0.05), The soil CH4 emission flux difference between natural community and tidal flats was significantly(P < 0.01).The soil CH4 emission flux difference between Plantation and tidal flats was significant(P < 0.05).