为研究辽河三角洲湿地的固碳能力,2010年5月在辽河三角洲双台子河口东侧的两个翅碱蓬湿地区域采取7个柱状样,通过对样品的化学分析测试,并利用210Pb测年法确定的沉积速率研究了土壤对碳的扣留速率,其结果表明:有机碳浓度分别与各营养元素浓度间有显著的正相关关系(p<0.01),指示沉积物中的有机物质对营养元素有很强的富集能力,同时营养元素促进植物的生长,从而影响土壤碳的加积速率.研究区总碳浓度范围为10.5~14.6 g/kg,其中约83%为有机碳,其相应的土壤对总碳和有机碳扣留速率分别为98.02~260.37 g/m2/a(均值171.84 g/m2/a)和81.17~229.98 g/m2/a(均值141.29 g/m2/a).本研究区,土壤对碳的扣留速率主要受土壤的沉积速率控制,并与高程有显著的相关关系(p<0.01).土壤对碳扣留机制的研究有助于加深对全球碳循的理解.
Carbon storage or sequestration is important in studying the global carbon cycle and budget.To evaluate carbon accumulation rate of S.salsa marsh along the vegetation coverage gradient,the authors collected 7 core samples from Liaohe Delta in May,2010.The sediment accretion rate was calculated by 210Pb dating method.The laboratory analyses focused on water content,bulk density,nutrient contents,Mehiich Ⅲ] extractable nutrients and carbon concentration.Remarkably,carbon concentration is significantly related to nutrient contents (p<0.01),implying that organic matters can effectively accumulate nutrient elements and support the growth of wetland vegetation,which favors carbon sequestration in the wetland soils.The results showed that total carbon concentration,about 83% of which is organic carbon,varies within 10.5-14.6 g/kg and carbon accumulation rates are in the ranges of 98.02-260.37 g/m2/a(for total carbon)and 81.17-229.98 g/m2/a (for organic carbon)respectively with the average accumulation rate of 171.84 g/m2/a for TC and 141.29 g/m2/a for Corg.Carbon accumulation rates are likely affected by sediment accretion rate which is significantly related to the elevation of each wetland (p<0.01).The implication is that not every wetland in different geological conditions and vegetation coverages is equally effective in sequestering carbon; it is important to address differences in wetland elevation,geological conditions and vegetation coverages when assessing the role of wetlands as carbon sinks in global carbon budgets.