干旱对亚马逊森林碳动态和碳流的影响
Christopher E Doughty1, D B Metcalfe2, C A J Girardin1
1Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, UK.
Nature
|March 6, 2015
概括
亚马逊干旱影响森林碳循环. 树木减少呼吸以维持生长,转移碳分配,并可能增加死亡率,尽管抑制光合作用.
科学领域:
- 生态生态学 生态生态学
- 气候科学 气候科学
- 林业林业 林业 林业 林业
背景情况:
- 亚马逊盆地在2005年和2010年经历了严重的干旱,与气候变化有关.
- 之前的研究表明,干旱后树木死亡率增加,二氧化碳吸收减少.
- 热带森林碳循环对干旱的准确反应仍然不完全理解.
研究的目的:
- 为了机械地理解2010年亚马逊干旱对森林碳循环的影响.
- 研究干旱如何影响净初级生产 (NPP),自营呼吸和异营呼吸.
- 量化干旱对光合作用产生盆地范围的影响.
主要方法:
- 利用了几年的数据,来自南美洲的13个1公森林地块.
- 单独测量NPP,自营呼吸和异营呼吸组成部分.
- 采用了叶子层面和地块层面的测量,并将降雨数据缩放为盆地范围的估计.
主要成果:
- 在2010年干旱期间,NPP总量保持不变.
- 自营呼吸,特别是根和茎的自营呼吸,在干旱结束时显著下降.
- 干旱抑制了整个亚马逊的光合作用,估计约有0.38百克的碳.
- 在干旱后的一年,碳分配从细根转移到树冠核电站.
结论:
- 亚马逊树木在干旱期间优先增长,通过减少与生长无关的自营养呼吸.
- 减少对组织维护和防御的投资可能解释了干旱后树木死亡率的增加.
- 干旱显著影响热带森林的碳动态,对生态系统的弹性产生影响.
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