长白山区泥炭地近200年来碳累积过程模拟

Modelling carbon accumulation process in peatlands for nearly 200 years,Changbai mountain

基于长白山区2个近200年210Pb定年的泥炭剖面数据,利用不同分解模型(单指数分解模型、双指数分解模型、线性分解模型)拟合估算了活跃层泥炭好氧分解过程中碳的输入率(p)、分解率(k)。通过敏感性分析,探讨p、k变化对泥炭地碳累积的影响。结果表明,近200年来,老里克泥炭剖面有机碳含量变化范围为34.4%~44.8%,碳累积速率(Rate of carbon accumulation,RCA)均值为79.9 g(/m^2·年);白江河泥炭剖面的有机碳含量变化范围为24.4%~42.5%,RCA均值为62.4 g(/m^2·年)。2个剖面的碳累积质量-年龄曲线都呈凹形,表明近200年来泥炭持续分解。3种模型中,单指数模型拟合效果最佳。根据模拟结果,老里克泥炭地的碳输入率为109.9407 g(/m^2·年),分解率为0.0055;比较而言,白江河泥炭地的输入率稍低,为87.4788 g(/m^2·年),而分解率更快,为0.0103。敏感性分析表明,在输入率恒定的情况下,增加分解率会使曲线向上移动(泥炭累积减少);而在分解率恒定的情况下,降低输入率会使曲线向上移动(泥炭累积减少)。与分解率相比,输入率对泥炭累积变化影响更大。

Based on the peat profile data of 210Pb fixed years in Changbai mountain area in recent 200 years,the carbon input rate(p)and decomposition rate(k)in the aerobic decomposition process of active layer peat were estimated by using different decomposition models(single exponential decomposition model,double exponential decomposition model and linear decomposition model)fitting.The effect of p and k on carbon accumulation in peatland was studied by sensitivity analysis.The results showed that the Laolike peat profile in the past 200 years;The organic carbon content varied from 34.4%to 44.8%,and the rate of carbon accumulation(Rate of carbon accumulation,RCA)averaged 79.9 g(/m^2·year).The variation range of organic carbon content in the peat profile of Baijianghe was from 24.4%to 42.5%,and the mean RCA was 62.4 g(/m^2·year).The carbon accumulation massage curves of both profiles were concave,indicating that peat continued to decompose in the past 200 years.Among the three models,the single exponential model had the best fitting effect.According to the simulation results,the carbon input rate of Laolike peatland was 109.9407 g(/m^2·year),and the decay rate was 0.0055;Comparatively speaking,the input rate of Baijiang peatland was slightly lower,which was 87.4788 g(/m^2·year),while the decay rate was faster,which was 0.0103.Sensitivity analysis showed that under the condition of constant input rate,increas⁃ing decay rate will cause the curve to move upward(peat accumulation decreases);At a constant decomposition rate,a reduction in the input rate would cause the curve to move upwards(a reduction in peat accumulation).Compared with the decomposition rate,the input rate had more influence on the accumulation of peat.