摘要
融雪期是北方地区可溶性有机碳(DOC)通过融雪径流从陆地生态系统向河流输出的关键时期,因此观测融雪径流DOC动态对分析流域碳流失至关重要。在帽儿山生态站选取东北东部典型天然次生林建立25 m×25 m的水量平衡场,测定分析2014年融雪期不同土层(5、35、65和95 cm)融雪径流DOC含量和通量的时间动态和垂直分布规律。结果表明:1)该融雪期土壤水量输入和输出分别为74.2和15.6 mm,径流率高达21%;融雪期DOC输出量与冬季大气输入量基本持平,分别为0.25和0.22 g/m2。2)高峰期DOC含量与其瞬时流量的相关性随土层而变。5和35 cm土层DOC含量与瞬时流量之间均无显著关系(P>0.05);65 cm土层则表现出弱负对数关系(R2=0.29,P<0.05),而95 cm土层呈现显著线性正相关(R2=0.43,P<0.05)。不同土层DOC瞬时通量与瞬时流量之间均极显著正相关(R2>0.9,P<0.001),且产流量越大的土层,其正相关回归方程的斜率也越大,表明水文驱动土壤DOC流失。3)融雪径流产流量和输出DOC通量大小均表现出35 cm>5 cm>95 cm>65 cm土层趋势,其中5和35 cm土层是DOC的主要输出层,占总输出量的70%,而在融雪高峰期可高达90%。由于土壤的滞留作用,DOC含量波动范围随土层加深而向低浓度收敛。
The dissolved organic carbon （DOC） during snowmeh period is crucial to analyzing carbon outputs from terrestrial ecosystems to rivers by streamflow in northern regions. The aim of this work was to quantify temporal dynamics and vertical distribution of DOC concentration and flux in snowmelt runoffs. A water balance plot with an area of 625 m2 was established in a typical temperate deciduous forest in Maoershan Forest Ecosystem Research Station, northeastern China, and the snowmeh runoffs and DOC concentrations at four different soil depths （5, 35, 65, and 95 cm） were measured in 2014. The results showed that ： 1 ） the inputs of water and DOC into the soil during the snowmeh period were 74.2 mm and 0.25 g/m2 , respectively, while the outputs were 15.6 mm and 0.22 g/m2 , respectively. The runoff rate reached approximately 21%, but the input and output of DOC were roughly balanced. 2） The relationships between DOC concentration and instantaneous water flow rate varied with soil depths during the peak period of snowmelt. DOC concentration and instantaneous water flow rate were not correlated significantly （P 〉 0.05） at 5 and 35 cm soil depths, but significantly, negatively correlated at 65 cm soil depth （R2 =0.29, P 〈0.05） and positively at 95 cm soil depth （R2 =0.43, P 〈0.05）. The instantaneous DOC flux and water flow rate were significantly, linearly correlated for all the soil depths （R2 〉 0.9, P 〈 0. 001 ）, and the greater the instantaneous water flow rates were, the steeper the slopes of the linear equations for the soil layers were, suggesting a hydrologically driven DOC loss. 3） Both DOC and water exported at different soil depths during the snowmeh period followed the order of 35 cm 〉 5 cm 〉 65 cm 〉 95 cm. The amount of water and DOC exported at 5 and 35 cm soil depths accounted for 70% of the total in the soil profile. The variability in DOC concentrations tended to converge to low concentration with the soil depth increasing due to the effect of soil retention
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2016年第11期1-8,共8页
Journal of Beijing Forestry University
基金
"十二五"国家科技支撑计划项目(2011BAD37B01)
教育部长江学者和创新团队发展计划项目(IRT_15R09)
关键词
碳流失
融雪径流
时间动态
垂直分布
温带森林
carbon loss
snowmelt runoff
temporal dynamics
vertical distribution
temperate forest
