Investigation On Community Structure And Carbon Storage Of Mangrove Ecosystem In Sanya River

Mangrove wetland ecosystem has the characteristics of strong carbon sink capacity and high carbon sequestration.In order to accurately grasp the carbon storage of mangrove wetland,this paper studied the carbon storage of mangrove wetland in Sanya River of Hainan Province.According to the field survey and the data of Sanya Forestry Research Institute,the distribution range and area of mangrove in Sanya River were obtained.The species,tree height,diameter at breast height,the number of respiratory roots and seedlings,plant height and diameter at breast height were measured by setting quadrats.The aboveground biomass and underground biomass of mangrove vegetation in Sanya River were calculated by allometric growth method.The biomasses of respiratory roots,seedlings and halopteris in Sanyahe mangrove wetland were measured by harvest method.The mangrove soil was sampled by setting quadrats and stratified sampling method,and the physical and chemical properties of the soil were measured.The content and density of organic carbon in different soil layers were by elemental analyzer.Finally,the carbon storage of aboveground part,underground part,seedling,respiratory root,fern and soil of mangrove wetland in Sanya River was obtained.The results are as follows:1.The mangrove wetland in Sanya River has a forest area of 67.14 hm2,the main mangrove species are mangrove,Rhizophora apiculata、Sonneratia apetala、Sonneratia caseolaris、Kandelia candel、Aegiceras corniculatum.2.The aboveground biomass of mangrove community in Sanya River was 298.01t/hm2,the underground biomass was 127.72t/hm2,the seedling biomass was 0.15t/hm2,the respiratory root biomass was 0.07t/hm2,and the halophyte biomass was 0.04t/hm2.The carbon storage of mangrove wetland vegetation in Sanya River is 28600.86t.The largest carbon storage is 9169953.47kg in aboveground part,accounting for 69.96%,followed by 3929808.63kg in underground part,accounting for 29.98%,4123.85kg in seedling part,accounting for 0.03%,1887.35kg in respiratory root part,accounting for 0.02%,and the lowest is 1026.62kg in Halopteridophyte part,accounting for 0.01%.3.Soil physical and chemical properties are different in different soil and soil depth.The average salinity is in the order of middle tide point>low tide point=high tide point.In the vertical distribution of soil,the water content of three sampling points decreases with the increase of soil depth.The average bulk density was in the order of middle tide point>high tide point>low tide point.In the vertical distribution of soil,the bulk density of low tide point and middle tide point decreased first and then increased,and the bulk density of high tide point decreased first and then increased and then decreased.The average pH value was in the order of low tide site>high tide site>middle tide site.In the vertical distribution of soil,the pH value of low tide site increased with the increase of soil depth,and the pH value of middle tide site and high tide site decreased first and then increased.The average salinity was in the order of low tide point>high tide point>middle tide point.In the vertical distribution,the salinity of the three sampling points decreased with the increase of soil depth.The main components of the three sampling points are sand,and the change of sand content in different soil depths is not obvious.4.Pearson correlation analysis was conducted between soil organic carbon content(TOC)and soil physical and chemical indicators,including water content,bulk density,pH,salinity and particle size.Through Pearson correlation analysis,soil organic carbon content was significantly positively correlated with water content,and soil organic carbon content was significantly negatively correlated with bulk density and pH values.Organic carbon content was not correlated with salinity,sand and silt.5.The soil organic carbon storage of mangrove wetland in Sanya River is 12.88kg/m2,and the vertical distribution of soil organic carbon content at each sampling point is generally consistent.The soil organic carbon content is the highest at 0-25cm depth,and with the increase of soil depth,the soil organic carbon content shows a significant decreasing trend.The total carbon storage of mangrove wetlands in Sanya River is 28653.26t.