清澜港红树林湿地典型群落类型沉积物活性有机碳组分分布特征

滩涂海岸红树林生态系统通常具有较高的土壤养分，尤其是沉积物有机碳含量。海南岛红树林种类丰富且生长较好，通过对红树林沉积物有机碳组分的基础研究有利于提高对红树林湿地固碳能力的评估精度，加深对海洋蓝碳的认识。以清澜港红树林5种典型群落类型为对象，比较分析表层土壤(0—10 cm)总有机碳(TOC)、微生物生物量碳(MBC)、易氧化有机碳(EOC)、可溶性有机碳(DOC)含量差异及其与土壤因子之间的相关性。结果表明：(1)不同群落类型间，土壤TOC、MBC、DOC和EOC含量均值分别为66.76 g/kg、177.08 mg/kg、25.49 mg/kg和2.34 g/kg。对比发现，土壤TOC在角果木群落中含量最高，但各群落间无显著差异；土壤MBC在不同群落间存在显著差异，其中角果木群落和杯萼海桑群落显著高于榄李群落；土壤DOC在不同群落间存在显著差异，其中海莲群落和角果木群落显著高于其余群落；土壤EOC在不同群落间存在显著差异，其中角果木群落显著高于海莲群落和正红树群落。(2)活性有机碳各个组分占总有机碳的比例均值大小依次为EOC>MBC>DOC。土壤EOC、MBC、DOC的...

Distribution characteristics of active organic carbon components in sediments of typical community types of mangrove wetland in Qinglan Port

Mangrove ecosystems in tidal flats usually contain a large proportion of soil nutrients, especially organic carbon content in sediments. The basic research on organic carbon components of the sediments in the large variety of luxuriant mangrove forests in Hainan Island can help more accurately evaluate the carbon sequestration capacity of mangrove wetlands and improve the knowledge about marine blue carbon. This paper comparatively analyzes the different contents of total organic carbon (TOC), microbial biomass carbon (MBC), easily oxidized organic carbon (EOC), and dissolved organic carbon (DOC) in the topsoil (0-10 cm) in five typical populations of mangrove in Qinglan Port and their correlation with soil factors. The result shows that (1) the average contents of TOC, MBC, DOC and EOC in the surface soils in different populations of mangrove are 66.76 g/kg, 177.08 mg/kg, 25.49 mg/kg, and 2.34 g/kg, respectively. According to the comparative analysis, the content of TOC is the highest in the soil in the Ceriops tagal community, but it is not significantly different among all the communities;The content of MBC in the soil is significantly different among all flora communities, where the content of MBC in the soil in Ceriops tagal community and Sonneratia alba community is much higher than that in Lumnitzera racemosa community. The content of DOC in the soil in all communities is significantly different, where the content of DOC in the soil in Bruguiera sexangula community and Ceriops tagal community is much higher than that in other communities. The content of EOC in the soil in all communities is significantly different, where the content of EOC in the soil in Ceriops tagal community is much higher than that in Bruguiera sexangula community and Rhizophora Apiculata community. (2) The average ratio of active organic carbon components to total organic carbon in MBC is higher than in DOC, and that in EOC is the highest. The distribution ratios of EOC, MBC and DOC in soil are between 3.23% and 4.02%, 0.22% and 0.36%, and 0.02% and 0.08% respectively. (3) Redundancy analysis shows that total nitrogen (TN) in soil is more justified to exclusively prove organic carbon components in the soil. Soil pH is less justified to exclusively prove the organic carbon component in the soil. (4) TOC, MBC, DOC and EOC in soil are positively correlated with soil TN and soil water content (SWC). In conclusion, tidal level soil physical and chemical properties caused by different biotic communities jointly affect the concentration of soil active organic carbon components.