滇东南典型岩溶湿地底泥钙形态分布

Distribution Characteristics of Different Calcium Speciation in the Sediment of Typical Karst Wetland in Southeast Yunnan

探讨岩溶地区稻田湿地—草甸湿地—湖滨湿地过程中底泥钙(Ca)形态的分布特征,为岩溶生态系统中钙循环及小流域的生境保护提供理论依据。在滇东南—普者黑岩溶湿地设置典型样地,采用典型样带布点方式并采用BCR连续提取方法,探索了稻田湿地、草甸湿地和湖滨湿地区域中底泥总Ca和各形态Ca(酸可提取态、可还原态、可氧化态、残渣态)含量的分布特征,并分析了各形态Ca间的相关性。结果表明:(1)稻田湿地—草甸湿地—湖滨湿地过程中表层底泥总钙与各形态钙分布特征一致,平均含量排序为:稻田湿地(14 423mg/kg)>湖滨湿地(10 863mg/kg)>草甸湿地(4 846mg/kg)。(2)各形态Ca组分中,以酸可提取态为主,占总量的50%以上,其次是可还原态,占30%以上,可氧化态及残渣态相差不明显,约占总量的20%。除残渣态外,湖滨湿地其余形态Ca含量均随底泥深度的增加而减小。(3)底泥总Ca与酸可提取态、可还原态、可氧化态Ca分别呈现极显著正相关(p<0.01),而与残渣态钙相关性不显著,酸可提取态Ca对总Ca的影响较大。普者黑底泥Ca含量因湿地类型的不同表现出显著的差异性。

This study explored the distribution of calcium(Ca)in paddy wetland-meadow wetland-lakeside wetland in the karst area,and provided the theoretical basis for the ecological cycling in the karst ecosystems and the ecological environment protection of the small watershed.Setting up the typical plots in the karst wetland of Puzhehei located in southeast of Yunnan Province,using the typical transect pattern of striping and using the BCR continuous extraction method,we explored the distribution characteristics of total calcium,the acid-soluble fraction,reducible fraction,oxidizable fraction,residual fraction in the paddy wetland,meadow wetland,lakeside wetland,and analyzed the correlation among the different calcium speciation.The results showed that:(1)the distribution characteristics of total calcium content of surface sediment was consistent with the form of calcium content in paddy wetland-meadow wetland-lakeside wetland;the average content decreased in the order:paddy wetland(14 423 mg/kg)>lakeside wetland(10 863 mg/kg)>meadow wetland(4 846 mg/kg);(2)the calcium among the different speciation was dominated by acid-soluble fraction,which accounted for above 50%of total Ca,followed by reducible fraction accounting for more than 30%,the oxidizable and residual fractions together accounted for 20%.In addition to the residual fraction of calcium,the remaining fraction of Ca in the lakeside wetland decreased with the depth of the sediment;(3)there was the significant positive correlation between the total Ca and the acid-soluble fraction,reducible fraction,oxidizable fraction of Ca(p<0.01),respectively,but not with the residual fraction of Ca.The acid-soluble fraction of Ca had the great impact on the total Ca.The calcium contents of sediments in Puzhehei showed the significant difference due to the different types of wetlands.