非线性草原对过去和未来大气CO2的反应
Richard A Gill1, H Wayne Polley, Hyrum B Johnson
1Department of Biology, Duke University, Durham, NC 27708-0340, USA. rgill@wsu.edu
Nature
|May 17, 2002
概括
土壤有机物可以储存碳,但它的容量有限. 大气中二氧化碳 (CO2) 的增加历来促进了植物生长和土壤碳,但未来的增加可能会受到的可用性限制.
科学领域:
- 生态生态学 生态生态学
- 生物地质化学生物地质化学
- 气候科学 气候科学
背景情况:
- 大气中二氧化碳 (CO2) 度的上升可以通过土壤碳封存来缓解.
- 土壤的碳储存受植物对二氧化碳的反应和营养素的可用性影响.
研究的目的:
- 研究土壤碳储存和循环对过去和未来大气二氧化碳增加的反应能力.
- 了解二氧化碳增加对草原植物生理学和土壤碳动态的影响.
主要方法:
- 利用了草原生态系统,其中大气二氧化碳度的持续梯度为 (200至550微摩尔mol(-1)).
- 测量了光合作用速率,植物组织化学,土壤碳池 (旧和新) 和的可用性.
主要成果:
- 升高的二氧化碳增加了光合作用速度,改变了植物组织的化学成分.
- 土壤碳在低二氧化碳下消失,但在高二氧化碳下保持稳定,这是由于抵消了旧和新碳动态.
- 在二氧化碳梯度上观察到气可用性的非线性,三倍下降.
结论:
- 土壤的碳储存和循环对历史的二氧化碳增加更敏感,而不是对预计的未来水平.
- 在未来二氧化碳升高的情况下,营养限制的增加可能会限制土壤作为碳汇的能力.
- 过去在土壤中的碳封存可能是显著的,但未来的潜力受到营养素的可用性限制.
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