长白山垂直带森林叶片-凋落物-土壤连续体有机碳动态——基于稳定性碳同位素分析

发布时间：2018-10-25 20:59

【摘要】：稳定性碳同位素自然丰度(δ~(13)C)记录着生态系统碳循环过程的关键信息,常被用于评价全球变化情景下陆地生态系统碳的动态。以长白山北坡垂直带4种典型森林生态系统为研究对象,测定乔木建群种叶片、凋落物以及不同深度土壤有机碳(SOC)含量和δ~(13)C值,探讨植物叶片-凋落物-土壤连续体碳含量、δ~(13)C丰度的分布格局及其生态学暗示。研究结果表明:植物叶片碳含量随海拔高度的增加呈现抛物线型变化,且阔叶树叶片碳含量显著低于针叶树,体现气候要素和植被功能型的支配作用,并且暗示针叶树种潜在的碳蓄积能力更强。此外,植物叶片δ~(13)C随海拔高度升高而降低,表明高海拔植物叶片水分利用效率较低,即固碳耗水成本更高。凋落物碳含量随海拔增加逐渐下降,而矿质表层土壤则表现为阔叶红松林、岳桦林显著高于暗针叶林,体现了植被类型和土壤质地的共同支配作用。总体上,岳桦林SOC周转最快,其次是暗针叶林,位于基带的阔叶红松林最慢。可见,小尺度上气候因子并不是温带森林地下碳循环的主导因素,植被功能型和土壤属性对SOC周转与稳定的影响更大。在探讨环境因子对陆地生态系统碳循环和碳平衡的影响时需要考虑研究尺度,不同的研究尺度影响SOC周转的驱动因子并不相同。研究方法方面,基于log SOC和δ~(13)C的SOM周转模型能够很好地概括不同生态系统类型下SOM周转的相对快慢,可用来评价SOC动态对全球变化的响应。
[Abstract]:The natural abundance of stable carbon isotopes (未 ~ (13) C), which records the key information of carbon cycle in ecosystems, is often used to evaluate the dynamics of terrestrial carbon in global change scenarios. Taking four typical forest ecosystems on the north slope of Changbai Mountain as the research object, the contents of (SOC) and 未 ~ (13) C in leaves, litter and soil of different depths of Arbor species were measured. The distribution pattern of 未 ~ (13) C abundance in plant leaves, litter and soil continuum and its ecological implications were studied. The results showed that the carbon content of plant leaves varied parabola with the increase of altitude, and the carbon content of broad-leaved leaves was significantly lower than that of coniferous trees, which reflected the dominance of climatic factors and vegetation functional types. It also suggests that the potential carbon accumulation of coniferous trees is stronger. In addition, 未 ~ (13) C of plant leaves decreased with the increase of altitude, which indicated that the water use efficiency of leaves at high altitude was lower, that is, the cost of carbon sequestration water consumption was higher. The carbon content of litter decreased gradually with the increase of altitude, while the mineral surface soil was shown as broad-leaved Korean pine forest, and the Yuebirch forest was significantly higher than the dark coniferous forest, which reflected the joint dominance of vegetation type and soil texture. In general, the SOC turnover of the birch forest was the fastest, followed by the dark coniferous forest, and the broad-leaved Korean pine forest located in the basal zone was the slowest. It can be seen that climate factor is not the dominant factor of underground carbon cycle in temperate forest on a small scale, and vegetation function type and soil attribute have more influence on SOC turnover and stability. In order to study the impact of environmental factors on the carbon cycle and carbon balance in terrestrial ecosystems, we should consider the scale of study. The driving factors of SOC turnover are not the same in different research scales. In terms of research methods, the SOM turnover model based on log SOC and 未 ~ (13) C can well summarize the relative speed of SOM turnover under different ecosystem types, and can be used to evaluate the dynamic response of SOC to global change.
【作者单位】：中国科学院大学资源与环境学院;中国科学院地理科学与资源研究所/生态系统观测与模拟重点实验室;
【基金】：国家自然科学基金资助项目(41471212,31470558,31290222,31290221) 国家重点研发计划资助项目(2016YFC0500603,2016YFC0503603) 青年创新研究团队资助项目(LENOM2016Q0004)
【分类号】：S714

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