Source and sink carbon dynamics and carbon allocation in the Amazon basin
Source and sink carbon dynamics and carbon allocation in the Amazon basin
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DOI：
10.1002/2014gb005028
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发表时间：
2015-05-01
影响因子：
5.2
通讯作者：
Malhi, Y.
中科院分区：
文献类型：
--
作者：
Doughty, Christopher E.;Metcalfe, D. B.;Malhi, Y.
热带森林碳循环的变化可能会影响全球气候，但此前由于缺乏实地数据，预测这种变化一直受到限制。这里我们展示了14个1公顷密集碳循环小区的完整碳循环的季节循环，我们将其分为三个区域：潮湿的低地、高地和干燥的低地。我们的数据突出了三个趋势：(1)总净第一性生产力(NPP)具有不同的季节性，高地和干旱低地在旱季达到峰值，潮湿低地在湿季达到峰值；(2)木材净第一性生产力(NPP)的季节性下降不是由总NPP的减少驱动的，而是由于在旱季期间碳优先分配给根部或冠层NPP，以及(3)总光合作用和总碳使用量(植物碳支出)之间存在时间脱钩。这种脱钩表明了非结构性碳水化合物的存在，这种碳水化合物可能允许增长和碳在最有利于生态的时候而不是最有利于环境的时候进行分配。
Changes to the carbon cycle in tropical forests could affect global climate, but predicting such changes has been previously limited by lack of field-based data. Here we show seasonal cycles of the complete carbon cycle for 14, 1ha intensive carbon cycling plots which we separate into three regions: humid lowland, highlands, and dry lowlands. Our data highlight three trends: (1) there is differing seasonality of total net primary productivity (NPP) with the highlands and dry lowlands peaking in the dry season and the humid lowland sites peaking in the wet season, (2) seasonal reductions in wood NPP are not driven by reductions in total NPP but by carbon during the dry season being preferentially allocated toward either roots or canopy NPP, and (3) there is a temporal decoupling between total photosynthesis and total carbon usage (plant carbon expenditure). This decoupling indicates the presence of nonstructural carbohydrates which may allow growth and carbon to be allocated when it is most ecologically beneficial rather than when it is most environmentally available.