Distribution Characteristics Of Soil Organic Carbon In Mangrove Wetlands In Hainan Island

90%of carbon in the existence of the orgnic carbon in soil. The net storage volume ofthe orgnic carbon make possible that the soil play an important role of carbon cycle in thegloble. Wetland is the important carbon stock which the SOC storage decomposes slowly;Then, wetland mineralizational decompose to produce greenhouse gases to form a hugecarbon source; What role can wetlands play in the global carbon cycle? It extently depend onthe net storage volume of SOC.To study the distribution regular of mangrove soil organic carbon and soil organic carboninfluencing factors, the mangrove lived in Hainan island was choosen. Include five areas:Haikou, Sanya, Danzhou, Dongfang and Wenchang; six type mangrove: Rhizophora stylosa,Sonneratia apetala, Avicennia marina, Ceriops tagal, Aegiceras corniculatum and Bruguieramarina. To collect the soil and date the soil pH、salinaty、temperature、moisture content、SOC content、soil total N content、total P content、total K content. To compute the SOCdensity and C/N. Data-processing by SPSS. The soil organic carbon content and its verticaldistribution of different areas and different types were analyzed. The results were contrastedand analyzed the mangrove soil organic carbon profiled distribution regulation and theenvironmental factors、climate、community structure and so on, that lead to the differentdistribution of SOC in mangrove of Hainan. The results showed that:1、Soil organic carbon content in1merers depth was in the range of63.53~838.01g/kg, andthe average was192.20g/kg. soil organic carbon density was19.12~149.04kg/m~2, and theaverage was43.12kg/m~2kg/m~2. Compared with other wetlands, Mangroves in Hainan islandhave higher content of SOC, mangrove was strong function of carbon sequestration.2、The vertical distribution feature is that the highest value of SOC content and density wereboth in20-40cm soil layer, and the lowest value were both in80-100cm. Under40cm, theincrease of soil depth the soil organic carbon was decrease. The SOC distribution regular wasdifferent in different areas and communitys because of the mangrove types and soil materials.The maximum SOC content of Avicennia marina in Dongfang at40-60cm,80-100cm was theminimum level; The Rhizophora stylosa in Danzhou’s SOC content at0-20cm、20-40cm、80-100cm、40-60cm、60-80cm from high to low. 3、The regular pattern of region distribution was: Sibi Bay and Wenchang was the area whichmangrove soil fixed highest soil organic carbon content. Danzhou and Haikou was next. Thelowest was Sanya River area. The average value was91.996g/kg、91.272g/kg、20.589g/kg、18.351g/kg、3.883g/kg. Result showed that, community composition, temperature,sedimentary environment, and other natural factors to influence the SOC.4、The SOC content in Dongzhai Harbour was significant different. Average value of SOCcontent is91.76g/kg. The highest value was the Bruguiera marina which content was104.47g/kg. Next is Rhizophora stylosa, Aegiceras corniculatum, Avicennia marina, Ceriopstagal, The lowest value was the Sonneratia apetala which content was74.43g/kg. In the20-40cm layer difference was not significant among communities, and showed a significantdifference in the other four layers. Result showed that, vegetation type, coverage, diameter,density influence the SOC.5、 C/N was the mineralization of soil factor. The average value of C/N order isWenchang>Sanya>Haikou>Dongfang>Danzhou; Ceriops tagal> Sonneratia apetala>Avicennia marina> Aegiceras corniculatum> Rhizophora stylosa> Bruguiera marina;0-20cm and80-100cm soil layer of Ceriops tagal was higher than other mangroves. C/Nfluctuant was not obvious in other mangroves. Sonneratia apetala’s soil maxmimum SOCcontent was20-40cm and40-60cm layer, the values are126.033and99.249. The combinedeffect of climatic conditions, geographical location, soil physical and chemical indicators ofhuman disturbance to influence the C/N.6、The soil relevant indicator showed that, there was significant correlation between soilorganic carbon content and SOC density&soil total N content&total P content (p<0.01);There was significant negative index correlation between soil organic carbon and soilmoisture content&soil total K content&soil salinity&pH (p<0.01); Soil organic carbonwas negative correlated with soil bulk density, and correlated with C/N, but the correlativitywas not significant.7、Mangrove litters and SOC content change dynamically over time. Results showed that, Themaximum value of the litter content at July, August and September, the minimum value atJanuary, February, March. The litter content in August have significant difference withFebruary and March. There was no significant different among other months. The mangrove litter content is mainly significantly affected by the temperature and meteorological factors inHainan island.8、To contrast different wetland soil organic carbon content and found that the mangrovehave higher soil organic carbon. The satellite images showed that Hainan island mangroveareas was3393.3ha, combined the soil organic carbon content. At a rough estimate, the soilorganic carbon reserves was2.39×106t (1m).