随着大气二氧化碳度的上升,森林用水效率的提高
Trevor F Keenan1, David Y Hollinger, Gil Bohrer
1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA. tkeenan@oeb.harvard.edu
Nature
|July 12, 2013
概括
由于大气中二氧化碳 (CO2) 水平的上升,森林的用水效率越来越高. 这种增强的效率,由二氧化碳施肥驱动,影响全球碳和水循环.
科学领域:
- 生态生态学 生态生态学
- 环境科学 环境科学
- 植物生理学 植物生理学
背景情况:
- 陆地植物通过光合作用来调节大气中的二氧化碳,这是一个与透气流失水的过程.
- 水利用效率 (WUE),即碳增加与水损失的比率,对生态系统功能和全球生物地球化学循环至关重要.
研究的目的:
- 通过直接生态系统测量,分析森林用水效率的长期趋势.
- 确定过去二十年来森林WUE观测变化背后的主要驱动因素.
主要方法:
- 对北半球温带和北极森林中整个生态系统碳和水交换的直接,长期测量的分析.
- 对竞争假设进行系统评估,以解释观察到的WUE趋势.
主要成果:
- 在过去的二十年中,森林用水效率大幅增加.
- WUE的增加最符合强烈的二氧化碳 (CO2) 施肥效应,导致部分口腔关闭.
- 观察到的WUE增加超过了现有理论和陆地生物圈模型的预测,与增加的光合作用,碳吸收和减少的蒸发转化相关.
结论:
- 森林用水效率显著提高,这表明陆地植被的碳和水动态发生了变化.
- 这些发现表明,在森林对气候变化的反应中,口腔调节的作用可能被低估了.
- 重新评估植被气候模型和口腔控制对气候变化相互作用的影响是有必要的.
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