在增加大气二氧化碳的条件下,实验性森林地块的土壤和垃圾中的有限碳储存
1Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA.
Nature
|May 25, 2001
概括
森林土壤可能不是长期的碳汇. 大气中二氧化碳的增加导致了垃圾碳的积累,但快速分解限制了其在这些生态系统中的储存潜力.
科学领域:
- 森林生态森林生态学
- 土壤科学 土壤科学
- 气候变化研究研究 气候变化研究
背景情况:
- 森林生态系统通过碳捕获起到缓解大气二氧化碳上升的作用.
- 土壤的碳储存取决于永久性有机物质的形成,如土.
- 了解森林土壤碳循环对于气候变化模型至关重要.
研究的目的:
- 调查二氧化碳度升高对林土壤中碳封存的影响.
- 评估森林土壤在增加大气CO2下作为长期碳沉积物的潜力.
主要方法:
- 实验性森林地块的松 (Pinus taeda) 被暴露在高度的二氧化碳中 (565μL L-1).
- 分析了不同植物组织 (树叶,木材) 和土壤层 (垃圾,矿物土壤) 的碳分配.
- 确定了垃圾层中的有机碳循环时间.
主要成果:
- 在三年暴露于高CO2水平后,在垃圾层中观察到大量的碳积累.
- 几乎一半的碳吸收被分配给短命的组织,主要是叶子.
- 快速的交换时间 (大约. 在垃圾层中发现有机碳 (3年).
- 在更深层的矿物土壤层中没有检测到任何显著的碳积累.
结论:
- 高度的二氧化碳增加了森林垃圾层中的碳,但快速分解限制了其长期储存潜力.
- 森林土壤,特别是垃圾层,在当前的气候变化情景下,可能不会作为重要的长期碳汇.
- 需要进一步的研究才能充分理解森林土壤中复杂的碳循环动态.
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