土壤的肥力限制了森林生态系统在二氧化碳丰富的大气中对碳的捕获
R Oren1, D S Ellsworth, K H Johnsen
1Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA. ramoren@duke.edu
Nature
|May 25, 2001
概括
森林吸收大气中的二氧化碳的能力受到土壤营养素的限制. 添加营养素显著增加了树木的碳捕获,特别是在较贫穷的土壤中,挑战了乐观的气候变化缓解估计.
科学领域:
- 森林生态 森林生态
- 生物地质化学生物地质化学
- 气候变化科学 气候变化科学
背景情况:
- 北部中度森林是重要的陆地碳汇.
- 大气中二氧化碳 (CO2) 的增加预计将增强森林的碳捕获.
- 森林的肥力,特别是的可用性,往往限制了树木的生长和碳吸收.
研究的目的:
- 调查营养限制对森林中二氧化碳诱导的碳封存的影响.
- 评估二氧化碳增加和营养添加对森林碳储存的协同效应.
- 重新评估围绕以森林为基础的气候变化缓解战略的乐观情绪.
主要方法:
- 进行了两次森林实验,使用成熟的松树暴露在高大气CO2的环境中.
- 通过将营养添加到实验场地来操纵营养的可用性.
- 测量 CO2 诱导的生物质碳增量随着时间的推移在不同土壤肥沃度的地点.
主要成果:
- 在没有添加营养的营养缺乏地点,二氧化碳诱导的碳封存是无法检测的.
- 营养添加显示出显著的协同效应,在较差的位置获得更大的收益.
- 升高的二氧化碳对碳封存的积极影响在没有添加营养物质的中等肥沃地点是暂时的和边际的.
结论:
- 土壤的肥力,特别是的可用性,大大限制了森林捕获碳的能力,以应对大气中二氧化碳的增加.
- 如果不考虑营养限制,目前对森林碳捕获潜力的估计可能过于乐观.
- 未来对碳封存的评估必须考虑到土壤肥力限制和与沉积的相互作用.
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